Sample records for abortive phage infection

  1. Effectiveness of the lactococcal abortive infection systems AbiA, AbiE, AbiF and AbiG against P335 type phages.

    PubMed

    Tangney, Mark; Fitzgerald, Gerald F

    2002-04-23

    Four lactococcal abortive infection mechanisms were introduced into strains which were sensitive hosts for P335 type phages and plaque assay experiments performed to assess their effect on five lactococcal bacteriophages from this family. Results indicate that AbiA inhibits all five P335 phages tested, while AbiG affects phiP335 itself and phiQ30 but not the other P335 species phages. AbiA was shown to retard phage Q30 DNA replication as previously reported for other phages. It was also demonstrated that AbiG, previously shown to act at a point after DNA replication in the cases of c2 type and 936 type phages, acts at the level of, or prior to phage Q30 DNA replication. AbiE and AbiF had no effect on the P335 type phages examined.

  2. AbiA, a lactococcal abortive infection mechanism functioning in Streptococcus thermophilus.

    PubMed

    Tangney, Mark; Fitzgerald, Gerald F

    2002-12-01

    The lactococcal abortive infection mechanisms AbiA and AbiG were introduced into Streptococcus thermophilus 4035, and a range of phages capable of infecting this host were examined for sensitivity to these mechanisms. AbiA proved effective against six phages when examined at a growth temperature of 30 degrees C but had no effect on any of the phages when tested at 37 or 42 degrees C. AbiG failed to affect any of the S. thermophilus phages at 30, 37, or 42 degrees C.

  3. Involvement of the Major Capsid Protein and Two Early-Expressed Phage Genes in the Activity of the Lactococcal Abortive Infection Mechanism AbiT

    PubMed Central

    Labrie, Simon J.; Tremblay, Denise M.; Moisan, Maxim; Villion, Manuela; Magadán, Alfonso H.; Campanacci, Valérie; Cambillau, Christian

    2012-01-01

    The dairy industry uses the mesophilic, Gram-positive, lactic acid bacterium (LAB) Lactococcus lactis to produce an array of fermented milk products. Milk fermentation processes are susceptible to contamination by virulent phages, but a plethora of phage control strategies are available. One of the most efficient is to use LAB strains carrying phage resistance systems such as abortive infection (Abi) mechanisms. Yet, the mode of action of most Abi systems remains poorly documented. Here, we shed further light on the antiviral activity of the lactococcal AbiT system. Twenty-eight AbiT-resistant phage mutants derived from the wild-type AbiT-sensitive lactococcal phages p2, bIL170, and P008 were isolated and characterized. Comparative genomic analyses identified three different genes that were mutated in these virulent AbiT-insensitive phage derivatives: e14 (bIL170 [e14bIL170]), orf41 (P008 [orf41P008]), and orf6 (p2 [orf6p2] and P008 [orf6P008]). The genes e14bIL170 and orf41P008 are part of the early-expressed genomic region, but bioinformatic analyses did not identify their putative function. orf6 is found in the phage morphogenesis module. Antibodies were raised against purified recombinant ORF6, and immunoelectron microscopy revealed that it is the major capsid protein (MCP). Coexpression in L. lactis of ORF6p2 and ORF5p2, a protease, led to the formation of procapsids. To our knowledge, AbiT is the first Abi system involving distinct phage genes. PMID:22820334

  4. Bypassing bacterial infection in phage display by sequencing DNA released from phage particles.

    PubMed

    Villequey, Camille; Kong, Xu-Dong; Heinis, Christian

    2017-11-01

    Phage display relies on a bacterial infection step in which the phage particles are replicated to perform multiple affinity selection rounds and to enable the identification of isolated clones by DNA sequencing. While this process is efficient for wild-type phage, the bacterial infection rate of phage with mutant or chemically modified coat proteins can be low. For example, a phage mutant with a disulfide-free p3 coat protein, used for the selection of bicyclic peptides, has a more than 100-fold reduced infection rate compared to the wild-type. A potential strategy for bypassing the bacterial infection step is to directly sequence DNA extracted from phage particles after a single round of phage panning using high-throughput sequencing. In this work, we have quantified the fraction of phage clones that can be identified by directly sequencing DNA from phage particles. The results show that the DNA of essentially all of the phage particles can be 'decoded', and that the sequence coverage for mutants equals that of amplified DNA extracted from cells infected with wild-type phage. This procedure is particularly attractive for selections with phage that have a compromised infection capacity, and it may allow phage display to be performed with particles that are not infective at all. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  5. Large-scale maps of variable infection efficiencies in aquatic Bacteroidetes phage-host model systems: Variable phage-host infection interactions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Holmfeldt, Karin; Solonenko, Natalie; Howard-Varona, Cristina

    Microbes drive ecosystem functioning and their viruses modulate these impacts through mortality, gene transfer and metabolic reprogramming. Despite the importance of virus-host interactions and likely variable infection efficiencies of individual phages across hosts, such variability is seldom quantified. In this paper, we quantify infection efficiencies of 38 phages against 19 host strains in aquatic Cellulophaga (Bacteroidetes) phage-host model systems. Binary data revealed that some phages infected only one strain while others infected 17, whereas quantitative data revealed that efficiency of infection could vary 10 orders of magnitude, even among phages within one population. This provides a baseline for understanding andmore » modeling intrapopulation host range variation. Genera specific host ranges were also informative. For example, the Cellulophaga Microviridae, showed a markedly broader intra-species host range than previously observed in Escherichia coli systems. Further, one phage genus, Cba41, was examined to investigate nonheritable changes in plating efficiency and burst size that depended on which host strain it most recently infected. While consistent with host modification of phage DNA, no differences in nucleotide sequence or DNA modifications were detected, leaving the observation repeatable, but the mechanism unresolved. Overall, this study highlights the importance of quantitatively considering replication variations in studies of phage-host interactions.« less

  6. Large-scale maps of variable infection efficiencies in aquatic Bacteroidetes phage-host model systems: Variable phage-host infection interactions

    DOE PAGES

    Holmfeldt, Karin; Solonenko, Natalie; Howard-Varona, Cristina; ...

    2016-06-28

    Microbes drive ecosystem functioning and their viruses modulate these impacts through mortality, gene transfer and metabolic reprogramming. Despite the importance of virus-host interactions and likely variable infection efficiencies of individual phages across hosts, such variability is seldom quantified. In this paper, we quantify infection efficiencies of 38 phages against 19 host strains in aquatic Cellulophaga (Bacteroidetes) phage-host model systems. Binary data revealed that some phages infected only one strain while others infected 17, whereas quantitative data revealed that efficiency of infection could vary 10 orders of magnitude, even among phages within one population. This provides a baseline for understanding andmore » modeling intrapopulation host range variation. Genera specific host ranges were also informative. For example, the Cellulophaga Microviridae, showed a markedly broader intra-species host range than previously observed in Escherichia coli systems. Further, one phage genus, Cba41, was examined to investigate nonheritable changes in plating efficiency and burst size that depended on which host strain it most recently infected. While consistent with host modification of phage DNA, no differences in nucleotide sequence or DNA modifications were detected, leaving the observation repeatable, but the mechanism unresolved. Overall, this study highlights the importance of quantitatively considering replication variations in studies of phage-host interactions.« less

  7. Phage-bacteria infection networks: From nestedness to modularity

    NASA Astrophysics Data System (ADS)

    Flores, Cesar O.; Valverde, Sergi; Weitz, Joshua S.

    2013-03-01

    Bacteriophages (viruses that infect bacteria) are the most abundant biological life-forms on Earth. However, very little is known regarding the structure of phage-bacteria infections. In a recent study we re-evaluated 38 prior studies and demonstrated that phage-bacteria infection networks tend to be statistically nested in small scale communities (Flores et al 2011). Nestedness is consistent with a hierarchy of infection and resistance within phages and bacteria, respectively. However, we predicted that at large scales, phage-bacteria infection networks should be typified by a modular structure. We evaluate and confirm this hypothesis using the most extensive study of phage-bacteria infections (Moebus and Nattkemper 1981). In this study, cross-infections were evaluated between 215 marine phages and 286 marine bacteria. We develop a novel multi-scale network analysis and find that the Moebus and Nattkemper (1981) study, is highly modular (at the whole network scale), yet also exhibits nestedness and modularity at the within-module scale. We examine the role of geography in driving these modular patterns and find evidence that phage-bacteria interactions can exhibit strong similarity despite large distances between sites. CFG acknowledges the support of CONACyT Foundation. JSW holds a Career Award at the Scientific Interface from the Burroughs Wellcome Fund and acknowledges the support of the James S. McDonnell Foundation

  8. Diversity and geographical distribution of Flavobacterium psychrophilum isolates and their phages: patterns of susceptibility to phage infection and phage host range.

    PubMed

    Castillo, Daniel; Christiansen, Rói Hammershaimb; Espejo, Romilio; Middelboe, Mathias

    2014-05-01

    Flavobacterium psychrophilum is an important fish pathogen worldwide that causes cold water disease (CWD) or rainbow trout fry syndrome (RTFS). Phage therapy has been suggested as an alternative method for the control of this pathogen in aquaculture. However, effective use of bacteriophages in disease control requires detailed knowledge about the diversity and dynamics of host susceptibility to phage infection. For this reason, we examined the genetic diversity of 49 F. psychrophilum strains isolated in three different areas (Chile, Denmark, and USA) through direct genome restriction enzyme analysis (DGREA) and their susceptibility to 33 bacteriophages isolated in Chile and Denmark, thus covering large geographical (>12,000 km) and temporal (>60 years) scales of isolation. An additional 40 phage-resistant isolates obtained from culture experiments after exposure to specific phages were examined for changes in phage susceptibility against the 33 phages. The F. psychrophilum and phage populations isolated from Chile and Denmark clustered into geographically distinct groups with respect to DGREA profile and host range, respectively. However, cross infection between Chilean phage isolates and Danish host isolates and vice versa was observed. Development of resistance to certain bacteriophages led to susceptibility to other phages suggesting that "enhanced infection" is potentially an important cost of resistance in F. psychrophilum, possibly contributing to the observed co-existence of phage-sensitive F. psychrophilum strains and lytic phages across local and global scales. Overall, our results showed that despite the identification of local communities of phages and hosts, some key properties determining phage infection patterns seem to be globally distributed.

  9. Toward Understanding Phage:Host Interactions in the Rumen; Complete Genome Sequences of Lytic Phages Infecting Rumen Bacteria

    PubMed Central

    Gilbert, Rosalind A.; Kelly, William J.; Altermann, Eric; Leahy, Sinead C.; Minchin, Catherine; Ouwerkerk, Diane; Klieve, Athol V.

    2017-01-01

    The rumen is known to harbor dense populations of bacteriophages (phages) predicted to be capable of infecting a diverse range of rumen bacteria. While bacterial genome sequencing projects are revealing the presence of phages which can integrate their DNA into the genome of their host to form stable, lysogenic associations, little is known of the genetics of phages which utilize lytic replication. These phages infect and replicate within the host, culminating in host lysis, and the release of progeny phage particles. While lytic phages for rumen bacteria have been previously isolated, their genomes have remained largely uncharacterized. Here we report the first complete genome sequences of lytic phage isolates specifically infecting three genera of rumen bacteria: Bacteroides, Ruminococcus, and Streptococcus. All phages were classified within the viral order Caudovirales and include two phage morphotypes, representative of the Siphoviridae and Podoviridae families. The phage genomes displayed modular organization and conserved viral genes were identified which enabled further classification and determination of closest phage relatives. Co-examination of bacterial host genomes led to the identification of several genes responsible for modulating phage:host interactions, including CRISPR/Cas elements and restriction-modification phage defense systems. These findings provide new genetic information and insights into how lytic phages may interact with bacteria of the rumen microbiome. PMID:29259581

  10. Characterization of Five Podoviridae Phages Infecting Citrobacter freundii

    PubMed Central

    Hamdi, Sana; Rousseau, Geneviève M.; Labrie, Simon J.; Kourda, Rim S.; Tremblay, Denise M.; Moineau, Sylvain; Slama, Karim B.

    2016-01-01

    Citrobacter freundii causes opportunistic infections in humans and animals, which are becoming difficult to treat due to increased antibiotic resistance. The aim of this study was to explore phages as potential antimicrobial agents against this opportunistic pathogen. We isolated and characterized five new virulent phages, SH1, SH2, SH3, SH4, and SH5 from sewage samples in Tunisia. Morphological and genomic analyses revealed that the five C. freundii phages belong to the Caudovirales order, Podoviridae family, and Autographivirinae subfamily. Their linear double-stranded DNA genomes range from 39,158 to 39,832 bp and are terminally redundant with direct repeats between 183 and 242 bp. The five genomes share the same organization as coliphage T7. Based on genomic comparisons and on the phylogeny of the DNA polymerases, we assigned the five phages to the T7virus genus but separated them into two different groups. Phages SH1 and SH2 are very similar to previously characterized phages phiYeO3-12 and phiSG-JL2, infecting, respectively, Yersinia enterocolitica and Salmonella enterica, as well as sharing more than 80% identity with most genes of coliphage T7. Phages SH3, SH4, and SH5 are very similar to phages K1F and Dev2, infecting, respectively, Escherichia coli and Cronobacter turicensis. Several structural proteins of phages SH1, SH3, and SH4 were detected by mass spectrometry. The five phages were also stable from pH 5 to 10. No genes coding for known virulence factors or integrases were found, suggesting that the five isolated phages could be good candidates for therapeutic applications to prevent or treat C. freundii infections. In addition, this study increases our knowledge about the evolutionary relationships within the T7virus genus. PMID:27446058

  11. Preventing pelvic infection after abortion.

    PubMed

    Stevenson, M M; Radcliffe, K W

    1995-01-01

    Pelvic infection is the commonest complication of legal abortion. The presence of lower genital tract infections increases the risk of complications, and women requesting abortion are at significant risk of harbouring sexually transmitted diseases (STD). Prophylactic antibiotic treatment can decrease the rate of post-abortal sepsis, but the optimum regime is unclear. In particular, patients with Chlamydia trachomatis infection, and bacterial vaginosis would appear to be at increased risk, and detection and treatment of these conditions can lower this risk. The opportunity to screen and treat for STD presents itself in this setting, allowing patients and their sexual contacts to benefit, with a decrease in the infected pool in the community.

  12. [Isolation and characterization of siphovirus phages infecting bovine Streptococcus agalactiae].

    PubMed

    Bai, Qinqin; Yang, Yongchun; Lu, Chengping

    2016-02-04

    To isolate and identify Streptococcus agalactiae phages and screen candidate phages to control infection caused by bovine S. agalactiae. We used two methods for isolation of S. agalactiae phages, namely (1) isolation of phages from milk and environmental samples, and (2) isolation of phages via induction of lysogens with Mitomycin C. Double-layer agar culture method was used to purify phages. Then the newly obtained phages, with S. agalactiae phage JX01 isolated from mastitis milk, were comparatively analyzed in the following aspects: morphology of phages by transmission electron microscopy, host range of phages to 55 S. agalactiae strains and other Streptococcus strains, phages DNA using EcoR I, Xba I, Pst I and Sal I, the optical multiplicity of infection, absorption curve and one step growth curve, and the stability of phages at different storage conditions. The comparative analysis of the 3 novel phages LYGO9, HZ04 and pA11 (induced from S. agalctiae bovine clinical isolate HAJL2011070601) with JX01 showed that the 4 phages were classified as the member of Siphovirdae family. EcoR I, Sal I, Xba I and Pst I separately digested the 4 phages DNA provided 4, 3, 3 and 2 profiles, respectively. This suggested that they were different strains. All the 4 phages specifically infected bovine S. agalactiae isolates. LYGO9, pA11, JX01 and HZ04 could lyse 12, 13, 20 and 23 of 42 tested bovine S. agalctiae isolates, respectively. This clearly indicated that these 4 phages are closely related. The 3 new phages which specifically lyse bovine S. agalactiae isolates are siphovirus phages. Phage LYGO9 was shown having a short latent period and a larger burst size.

  13. SP10 Infectivity Is Aborted after Bacteriophage SP10 Infection Induces nonA Transcription on the Prophage SPβ Region of the Bacillus subtilis Genome

    PubMed Central

    Yamamoto, Tatsuya; Obana, Nozomu; Yee, Lii Mien; Asai, Kei; Nomura, Nobuhiko

    2014-01-01

    Bacteria have developed various strategies for phage resistance. Infection with phage induces the transcription of part of the phage resistance gene, but the regulatory mechanisms of such transcription remain largely unknown. The phage resistance gene nonA is located on the SPβ prophage region of the Bacillus subtilis Marburg strain genome. The nonA transcript was detected at the late stage of SP10 infection but is undetectable in noninfected cells. The nonA transcript was detected after the induction of the sigma factor Orf199-Orf200 (σOrf199-200), when sigma factors encoded in the SP10 genome were expressed from a xylose-inducible plasmid. Thus, the SP10 sigma factor is an activator of a set of SP10 genes and nonA. The nonA gene encodes a 72-amino-acid protein with a transmembrane motif and has no significant homology with any protein in any database. NonA overexpression halted cell growth and reduced the efficiency of B. subtilis colony formation and respiration activity. In addition, SP10 virion protein synthesis was inhibited in the nonA+ strain, and SP10 virion particles were scarce in it. These results indicate that NonA is a novel protein that can abort SP10 infection, and its transcription was regulated by SP10 sigma factor. PMID:24272782

  14. Engineered phage-based therapeutic materials inhibit Chlamydia trachomatis intracellular infection

    PubMed Central

    Bhattarai, Shanta Raj; Yoo, So Young; Lee, Seung-Wuk; Dean, Deborah

    2012-01-01

    Developing materials that are effective against sexually transmitted pathogens such as Chlamydia trachomatis (Ct) and HIV-1 is challenging both in terms of material selection and improving bio-membrane and cellular permeability at desired mucosal sites. Here, we engineered the prokaryotic bacterial virus (M13 phage) carrying two functional peptides, integrin binding peptide (RGD) and a segment of the polymorphic membrane protein D (PmpD) from Ct, as a phage-based material that can ameliorate Ct infection. Ct is a globally prevalent human pathogen for which there are no effective vaccines or microbicides. We show that engineered phage stably express both RGD motifs and Ct peptides and traffic intracellularly and into the lumen of the inclusion in which the organism resides within the host cell. Engineered phage were able to significantly reduce Ct infection in both HeLa and primary endocervical cells compared with Ct infection alone. Polyclonal antibodies raised against PmpD and co-incubated with constructs prior to infection did not alter the course of infection, indicating that PmpD is responsible for the observed decrease in Ct infection. Our results suggest that phage-based design approaches to vector delivery that overcome mucosal cellular barriers may be effective in preventing Ct and other sexually transmitted pathogens. PMID:22494890

  15. Dynamics of success and failure in phage and antibiotic therapy in experimental infections.

    PubMed

    Bull, J J; Levin, Bruce R; DeRouin, Terry; Walker, Nina; Bloch, Craig A

    2002-11-26

    In 1982 Smith and Huggins showed that bacteriophages could be at least as effective as antibiotics in preventing mortality from experimental infections with a capsulated E. coli (K1) in mice. Phages that required the K1 capsule for infection were more effective than phages that did not require this capsule, but the efficacies of phages and antibiotics in preventing mortality both declined with time between infection and treatment, becoming virtually ineffective within 16 hours. We develop quantitative microbiological procedures that (1) explore the in vivo processes responsible for the efficacy of phage and antibiotic treatment protocols in experimental infections (the Resistance Competition Assay, or RCA), and (2) survey the therapeutic potential of phages in vitro (the Phage Replication Assay or PRA). We illustrate the application and utility of these methods in a repetition of Smith and Huggins' experiments, using the E. coli K1 mouse thigh infection model, and applying treatments of phages or streptomycin. 1) The Smith and Huggins phage and antibiotic therapy results are quantitatively and qualitatively robust. (2) Our RCA values reflect the microbiological efficacies of the different phages and of streptomycin in preventing mortality, and reflect the decline in their efficacy with a delay in treatment. These results show specifically that bacteria become refractory to treatment over the term of infection. (3) The K1-specific and non-specific phages had similar replication rates on bacteria grown in broth (based on the PRA), but the K1-specific phage had markedly greater replication rates in mouse serum.

  16. Treatment of in vitro enterohemorrhagic Escherichia coli infection using phage and probiotics.

    PubMed

    Dini, C; Bolla, P A; de Urraza, P J

    2016-07-01

    To assay the combination of phage and probiotics against EHEC in vitro on infected Hep-2 cells. Phage and probiotics treatments on EHEC O157:H7-infected Hep-2 cells were assayed individually or combined. The effect of freeze-drying on phage and probiotic antimicrobial activity was also studied. While treatment with phage alone increased cell detachment caused by EHEC infection, the treatments with MM alone or in combination with phage proved to effectively diminish cell damage caused by EHEC infection. Combined treatment showed a decrease in apoptotic cell count of 57·3% and a reduction in EHEC adhesion to cell monolayer of 1·2 log CFU. The simultaneous use of phage and probiotics showed no antagonistic effect, and freeze-drying did not affect their antipathogenic activity. The combination of phage and probiotics has great potential for reducing the number of pathogens adhered to epithelial cells during EHEC O157:H7 infection and attenuating the cytotoxic effect derived from it. Further in vivo assays are needed for assessing the actual effectiveness of the treatment. This study presents a freeze-dried formulation of phage and probiotics capable of controlling EHEC infections and reducing epithelial cell damage in vitro. © 2016 The Society for Applied Microbiology.

  17. Preventing infective complications relating to induced abortion.

    PubMed

    Mary, Nirmala; Mahmood, Tahir A

    2010-08-01

    Infective complications following induced abortions are still a common cause of morbidity and mortality. This review focusses on defining the strategies to improve care of women seeking an induced abortion and to reduce infective complications. We have considered the evidence for screening and cost-effectiveness for antibiotic prophylaxis. Current evidence suggests that treating all women with prophylactic antibiotics in preference to screening and treating is the most cost-effective way of reducing infective complications following induced abortions. The final strategy to prevent infective complications should be individualized for each region/area depending on the prevalence of organisms causing pelvic infections and the resources available. 2010 Elsevier Ltd. All rights reserved.

  18. Stochasticity in the Expression of LamB and its Affect on λ phage Infection

    NASA Astrophysics Data System (ADS)

    Chapman, Emily; Wu, Xiao-Lun

    2006-03-01

    λ phage binds to E. Coli's lamB protein and injects its DNA into the cell. The phage quickly replicates and after a latent period the bacteria bursts, emitting mature phages. We developed a mathematical model based on the known physical events that occur when a λ phage infects an E.Coli cell. The results of these models predict that the bacteria and phage populations become extinct unless the parameters of the model are very finely tuned, which is untrue in the nature. The lamB protein is part of the maltose regulon and can be repressed to minimal levels when grown in the absence of inducer. Therefore, a cell that is not expressing any lamB protein at that moment is resistant against phage infection. We studied the dynamic relationship between λ phage and E. Coli when the concentration of phage greatly outnumbers the concentration of bacteria. We study how the stochasticity of the expression of lamB affects the percentage of cells that the λ phage infects. We show that even in the case when the maltose regulon is fully induced a percentage of cells continue to persist against phage infection.

  19. Isolation and Characterization of Phages Infecting Bacillus subtilis

    PubMed Central

    Biegalska, Anna; Łoś, Marcin; Richert, Malwina

    2015-01-01

    Bacteriophages have been suggested as an alternative approach to reduce the amount of pathogens in various applications. Bacteriophages of various specificity and virulence were isolated as a means of controlling food-borne pathogens. We studied the interaction of bacteriophages with Bacillus species, which are very often persistent in industrial applications such as food production due to their antibiotic resistance and spore formation. A comparative study using electron microscopy, PFGE, and SDS-PAGE as well as determination of host range, pH and temperature resistance, adsorption rate, latent time, and phage burst size was performed on three phages of the Myoviridae family and one phage of the Siphoviridae family which infected Bacillus subtilis strains. The phages are morphologically different and characterized by icosahedral heads and contractile (SIOΦ, SUBω, and SPOσ phages) or noncontractile (ARπ phage) tails. The genomes of SIOΦ and SUBω are composed of 154 kb. The capsid of SIOΦ is composed of four proteins. Bacteriophages SPOσ and ARπ have genome sizes of 25 kbp and 40 kbp, respectively. Both phages as well as SUBω phage have 14 proteins in their capsids. Phages SIOΦ and SPOσ are resistant to high temperatures and to the acid (4.0) and alkaline (9.0 and 10.0) pH. PMID:26273592

  20. Phage therapy dosing: The problem(s) with multiplicity of infection (MOI).

    PubMed

    Abedon, Stephen T

    2016-01-01

    The concept of bacteriophage multiplicity of infection (MOI) - ratios of phages to bacteria - historically has been less easily applied than many phage workers would prefer or, perhaps, may be aware. Here, toward clarification of the concept, I discuss multiplicity of infection in terms of semantics, history, mathematics, pharmacology, and actual practice. For phage therapy and other biocontrol purposes it is desirable, especially, not to solely employ MOI to describe what phage quantities have been applied during dosing. Why? Bacterial densities can change between bacterial challenge and phage application, may not be easily determined immediately prior to phage dosing, and/or target bacterial populations may not be homogeneous with regard to phage access and thereby inconsistent in terms of what MOI individual bacteria experience. Toward experiment reproducibility and as practiced generally for antibacterial application, phage dosing instead should be described in terms of concentrations of formulations (phage titers) as well as volumes applied and, in many cases, absolute numbers of phages delivered. Such an approach typically will be far more desirable from a pharmacological perspective than solely indicating ratios of agents to bacteria. This essay was adapted, with permission, from an appendix of the 2011 monograph, Bacteriophages and Biofilms , Nova Science Publishers.

  1. In vivo growth rates are poorly correlated with phage therapy success in a mouse infection model.

    PubMed

    Bull, J J; Otto, G; Molineux, I J

    2012-02-01

    Two classes of phages yield profoundly different levels of recovery in mice experimentally infected with an Escherichia coli O18:K1:H7 strain. Phages requiring the K1 capsule for infection (K1-dep) rescue virtually all infected mice, whereas phages not requiring the capsule (K1-ind) rescue modest numbers (∼30%). To rescue infected mice, K1-ind phages require at least a 10(6)-fold-higher inoculum than K1-dep phages. Yet their in vivo growth dynamics are only modestly inferior to those of K1-dep phages, and competition between the two phage types in the same mouse reveals only a slight growth advantage for the K1-dep phage. The in vivo growth rate seems unlikely to be the primary determinant of phage therapy success. An alternative explanation is that the success of K1-dep phages is due substantially to their proteomic composition. They encode an enzyme that degrades the K1 capsule, which has been shown in other work to be sufficient to cure infection in the complete absence of phages.

  2. Initiation of Phage Infection by Partial Unfolding and Prolyl Isomerization*♦

    PubMed Central

    Hoffmann-Thoms, Stephanie; Weininger, Ulrich; Eckert, Barbara; Jakob, Roman P.; Koch, Johanna R.; Balbach, Jochen; Schmid, Franz X.

    2013-01-01

    Infection of Escherichia coli by the filamentous phage fd starts with the binding of the N2 domain of the phage gene-3-protein to an F pilus. This interaction triggers partial unfolding of the gene-3-protein, cis → trans isomerization at Pro-213, and domain disassembly, thereby exposing its binding site for the ultimate receptor TolA. The trans-proline sets a molecular timer to maintain the binding-active state long enough for the phage to interact with TolA. We elucidated the changes in structure and local stability that lead to partial unfolding and thus to the activation of the gene-3-protein for phage infection. Protein folding and TolA binding experiments were combined with real-time NMR spectroscopy, amide hydrogen exchange measurements, and phage infectivity assays. In combination, the results provide a molecular picture of how a local unfolding reaction couples with prolyl isomerization not only to generate the activated state of a protein but also to maintain it for an extended time. PMID:23486474

  3. Diversity of phage infection types and associated terminology: the problem with 'Lytic or lysogenic'.

    PubMed

    Hobbs, Zack; Abedon, Stephen T

    2016-04-01

    Bacteriophages, or phages, are viruses of members of domain Bacteria. These viruses play numerous roles in shaping the diversity of microbial communities, with impact differing depending on what infection strategies specific phages employ. From an applied perspective, these especially are communities containing undesired or pathogenic bacteria that can be modified through phage-mediated bacterial biocontrol, that is, through phage therapy. Here we seek to categorize phages in terms of their infection strategies as well as review or suggest more descriptive, accurate or distinguishing terminology. Categories can be differentiated in terms of (1) whether or not virion release occurs (productive infections versus lysogeny, pseudolysogeny and/or the phage carrier state), (2) the means of virion release (lytic versus chronic release) and (3) the degree to which phages are genetically equipped to display lysogenic cycles (temperate versus non-temperate phages). We address in particular the use or overuse of what can be a somewhat equivocal phrase, 'Lytic or lysogenic', especially when employed as a means of distinguishing among phages types. We suggest that the implied dichotomy is inconsistent with both modern as well as historical understanding of phage biology. We consider, therefore, less ambiguous terminology for distinguishing between 'Lytic' versus 'Lysogenic' phage types. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Phage-Encoded Colanic Acid-Degrading Enzyme Permits Lytic Phage Infection of a Capsule-Forming Resistant Mutant Escherichia coli Strain

    PubMed Central

    Kim, Min Soo; Kim, Young Deuk; Hong, Sung Sik; Park, Kwangseo; Ko, Kwan Soo

    2014-01-01

    In this study, we isolated a bacteriophage T7-resistant mutant strain of Escherichia coli (named S3) and then proceeded to characterize it. The mutant bacterial colonies appeared to be mucoid. Microarray analysis revealed that genes related to colanic acid production were upregulated in the mutant. Increases in colanic acid production by the mutant bacteria were observed when l-fucose was measured biochemically, and protective capsule formation was observed under an electron microscope. We found a point mutation in the lon gene promoter in S3, the mutant bacterium. Overproduction of colanic acid was observed in some phage-resistant mutant bacteria after infection with other bacteriophages, T4 and lambda. Colanic acid overproduction was also observed in clinical isolates of E. coli upon phage infection. The overproduction of colanic acid resulted in the inhibition of bacteriophage adsorption to the host. Biofilm formation initially decreased shortly after infection but eventually increased after 48 h of incubation due to the emergence of the mutant bacteria. Bacteriophage PBECO4 was shown to infect the colanic acid-overproducing mutant strains of E. coli. We confirmed that the gene product of open reading frame 547 (ORF547) of PBECO4 harbored colanic acid-degrading enzymatic (CAE) activity. Treatment of the T7-resistant bacteria with both T7 and PBECO4 or its purified enzyme (CAE) led to successful T7 infection. Biofilm formation decreased with the mixed infection, too. This procedure, using a phage cocktail different from those exploiting solely receptor differences, represents a novel strategy for overcoming phage resistance in mutant bacteria. PMID:25416767

  5. Bacteriophage T4 Infection of Stationary Phase E. coli: Life after Log from a Phage Perspective

    PubMed Central

    Bryan, Daniel; El-Shibiny, Ayman; Hobbs, Zack; Porter, Jillian; Kutter, Elizabeth M.

    2016-01-01

    Virtually all studies of phage infections investigate bacteria growing exponentially in rich media. In nature, however, phages largely encounter non-growing cells. Bacteria entering stationary phase often activate well-studied stress defense mechanisms that drastically alter the cell, facilitating its long-term survival. An understanding of phage-host interactions in such conditions is of major importance from both an ecological and therapeutic standpoint. Here, we show that bacteriophage T4 can efficiently bind to, infect and kill E. coli in stationary phase, both in the presence and absence of a functional stationary-phase sigma factor, and explore the response of T4-infected stationary phase cells to the addition of fresh nutrients 5 or 24 h after that infection. An unexpected new mode of response has been identified. “Hibernation” mode is a persistent but reversible dormant state in which the infected cells make at least some phage enzymes, but halt phage development until appropriate nutrients become available before producing phage particles. Our evidence indicates that the block in hibernation mode occurs after the middle-mode stage of phage development; host DNA breakdown and the incorporation of the released nucleotides into phage DNA indicate that the enzymes of the nucleotide synthesizing complex, under middle-mode control, have been made and assembled into a functional state. Once fresh glucose and amino acids become available, the standard lytic infection process rapidly resumes and concentrations of up to 1011 progeny phage (an average of about 40 phage per initially present cell) are produced. All evidence is consistent with the hibernation-mode control point lying between middle mode and late mode T4 gene expression. We have also observed a “scavenger” response, where the infecting phage takes advantage of whatever few nutrients are available to produce small quantities of progeny within 2 to 5 h after infection. The scavenger response seems

  6. Perspectives of Phage-Eukaryotic Cell Interactions to Control Epstein-Barr Virus Infections.

    PubMed

    Górski, Andrzej; Międzybrodzki, Ryszard; Jończyk-Matysiak, Ewa; Weber-Dąbrowska, Beata; Bagińska, Natalia; Borysowski, Jan

    2018-01-01

    Recently, leading medical journals emphasized the importance of further studies on the potential application of bacterial viruses (phages) for the treatment of antibiotics-resistant infections outlining the present status of the therapy and perspectives for the future. Furthermore, a leading scientific journal pointed to the recent progress in research on phage interactions with eukaryotic cells (especially cells of the immune system) and potential implications of their results for our broader understanding of the role of phages - not only as "bacteria eaters" - but also as an important part of our body defense protecting against external and internal pathogenic invaders (as suggested previously). This illustrates how our understanding of the actual role and potential of phages is expanding and how worldwide interest in their use in medicine is growing. In this article we envision how this advancement of our knowledge about phages could be translated into the progress in combating herpesvirus infections especially those caused by Epstein-Barr virus (EBV).

  7. Association between Ureaplasma urealyticum endocervical infection and spontaneous abortion.

    PubMed

    Ahmadi, Amjad; Khodabandehloo, Mazaher; Ramazanzadeh, Rashid; Farhadifar, Fariba; Nikkhoo, Bahram; Soofizade, Nasrin; Rezaii, Masoome

    2014-12-01

    Ureaplasma urealyticum can colonize women genital tract and be isolated from the amniotic fluid of women with adverse pregnancy outcomes. The association of U. urealyticum with spontaneous abortion remains controversial. The aim of this study was to evaluate the frequency of U. urealyticum infection among pregnant women and its association with spontaneous abortion. In this case-control study we included 109 women with spontaneous abortion with gestation age between 10-20 weeks (Cases), and 109 women with normal pregnancy with gestation age between 20-30 weeks (Controls) in Sanandaj, Iran. Using specific primers and extracted DNA from endocervical swabs, a PCR test was conducted for detection of U. urealyticum in both women groups. Total prevalence of U. urealyticum infection in women was 26 out of 218 cases (11.92%). The prevalence of U. urealyticum infection was 18 out of 109 (16.5%) and 8 out of 109 (7.3%) in case (spontaneous abortion) and control groups, respectively. Using chi-square test, association between U. urealyticum infection and spontaneous abortion was statistically significant (P<0.05). Colonization of U. urealyticum in genital tract of women, and its asymptomatic feature in combination with other factors such as other microorganisms or cervical incompetence may induce spontaneous abortion. Further studies are needed to confirm this possibility.

  8. Protist predation can select for bacteria with lowered susceptibility to infection by lytic phages.

    PubMed

    Örmälä-Odegrip, Anni-Maria; Ojala, Ville; Hiltunen, Teppo; Zhang, Ji; Bamford, Jaana K H; Laakso, Jouni

    2015-05-07

    Consumer-resource interactions constitute one of the most common types of interspecific antagonistic interaction. In natural communities, complex species interactions are likely to affect the outcomes of reciprocal co-evolution between consumers and their resource species. Individuals face multiple enemies simultaneously, and consequently they need to adapt to several different types of enemy pressures. In this study, we assessed how protist predation affects the susceptibility of bacterial populations to infection by viral parasites, and whether there is an associated cost of defence on the competitive ability of the bacteria. As a study system we used Serratia marcescens and its lytic bacteriophage, along with two bacteriovorous protists with distinct feeding modes: Tetrahymena thermophila (particle feeder) and Acanthamoeba castellanii (surface feeder). The results were further confirmed with another study system with Pseudomonas and Tetrahymena thermophila. We found that selection by protist predators lowered the susceptibility to infections by lytic phages in Serratia and Pseudomonas. In Serratia, concurrent selection by phages and protists led to lowered susceptibility to phage infections and this effect was independent from whether the bacteria shared a co-evolutionary history with the phage population or not. Bacteria that had evolved with phages were overall more susceptible to phage infection (compared to bacteria with history with multiple enemies) but they were less vulnerable to the phages they had co-evolved with than ancestral phages. Selection by bacterial enemies was costly in general and was seen as a lowered fitness in absence of phages, measured as a biomass yield. Our results show the significance of multiple species interactions on pairwise consumer-resource interaction, and suggest potential overlap in defending against predatory and parasitic enemies in microbial consumer-resource communities. Ultimately, our results could have larger scale

  9. Genomic Characterization of a Novel Phage Found in Black Abalone (Haliotis cracherodii) Infected with Withering Syndrome

    NASA Astrophysics Data System (ADS)

    Closek, C. J.; Langevin, S.; Burge, C. A.; Crosson, L.; White, S.; Friedman, C. S.

    2016-02-01

    Withering syndrome (WS), caused by the bacterium Candidatus Xenohaliotis californiensis, a Rickettsia-like organism (RLO), infects many species of abalone. Black abalone (Haliotis cracherodii), one of two endangered species of abalone, has experienced high population losses along the California coast due to WS. Recently, we observed reduced pathogenicity and mortality events in RLO-infected abalone when a novel bacteriophage (phage) was also present. To better understand phage-bacterium dynamics and develop more informative diagnostic tools, we sequenced the genome of the novel phage associated with the RLO responsible for WS. Metagenomic sequencing libraries were prepared with extracted genomic DNA from two experimentally infected H. cracherodii and phage sequences were enriched using hydroxyapatite chromatography normalization. Normalized libraries were individually barcoded and sequenced with Illumina MiSeq. Raw sequence reads were processed using VIrominer and de novo assembly produced one single phage-like contig (35.7Kb) from the experimentally infected abalone. This highly divergent genome had closest homology with a virus associated with abalone shriveling syndrome (SS). Of the 34 predicted ORFs, overlapping homology with the SS virus ranged from 20-72%, demonstrating the phage sequenced is genetically distinct from any known phage. The phage-like sequences represented a significant portion of the total reads sequenced ( 2 million of the 12 million paired-end reads; 17%) and we obtained 94,000X coverage across the novel phage genome. Beyond characterization of this novel phage, which appears to reduce pathogenicity of the RLO, the genome enabled us to develop quantitative PCR and in situ hybridization assays as diagnostic tools. These tools allow us to detect and quantify this phage in the endangered H. cracherodii.

  10. Inhaled phage therapy: a promising and challenging approach to treat bacterial respiratory infections.

    PubMed

    Bodier-Montagutelli, Elsa; Morello, Eric; L'Hostis, Guillaume; Guillon, Antoine; Dalloneau, Emilie; Respaud, Renaud; Pallaoro, Nikita; Blois, Hélène; Vecellio, Laurent; Gabard, Jérôme; Heuzé-Vourc'h, Nathalie

    2017-08-01

    Bacterial respiratory tract infections (RTIs) are increasingly difficult to treat due to evolving antibiotic resistance. In this context, bacteriophages (or phages) are part of the foreseen alternatives or combination therapies. Delivering phages through the airways seems more relevant to accumulate these natural antibacterial viruses in proximity to their bacterial host, within the infectious site. Areas covered: This review addresses the potential of phage therapy to treat RTIs and discusses preclinical and clinical results of phages administration in this context. Recent phage formulation and aerosolization attempts are also reviewed, raising technical challenges to achieve efficient pulmonary deposition via inhalation. Expert opinion: Overall, the inhalation of phages as antibacterial treatment seems both clinically relevant and technically feasible. Several crucial points still need to be investigated, such as phage product pharmacokinetics and immunogenicity. Furthermore, given phage-specific features, appropriate regulatory and manufacturing guidelines will need to be defined. Finally, randomized controlled clinical trials should be carried out to establish phage therapy's clinical positioning in the antimicrobial arsenal against RTIs.

  11. Strain Specific Phage Treatment for Staphylococcus aureus Infection Is Influenced by Host Immunity and Site of Infection.

    PubMed

    Pincus, Nathan B; Reckhow, Jensen D; Saleem, Danial; Jammeh, Momodou L; Datta, Sandip K; Myles, Ian A

    2015-01-01

    The response to multi-drug resistant bacterial infections must be a global priority. While mounting resistance threatens to create what the World Health Organization has termed a "post-antibiotic era", the recent discovery that antibiotic use may adversely impact the microbiome adds further urgency to the need for new developmental approaches for anti-pathogen treatments. Methicillin-resistant Staphylococcus aureus (MRSA), in particular, has declared itself a serious threat within the United States and abroad. A potential solution to the problem of antibiotic resistance may not entail looking to the future for completely novel treatments, but instead looking into our history of bacteriophage therapy. This study aimed to test the efficacy, safety, and commercial viability of the use of phages to treat Staphylococcus aureus infections using the commercially available phage SATA-8505. We found that SATA-8505 effectively controls S. aureus growth and reduces bacterial viability both in vitro and in a skin infection mouse model. However, this killing effect was not observed when phage was cultured in the presence of human whole blood. SATA-8505 did not induce inflammatory responses in peripheral blood mononuclear cultures. However, phage did induce IFN gamma production in primary human keratinocyte cultures and induced inflammatory responses in our mouse models, particularly in a mouse model of chronic granulomatous disease. Our findings support the potential efficacy of phage therapy, although regulatory and market factors may limit its wider investigation and use.

  12. Impact of reducing and oxidizing agents on the infectivity of Qβ phage and the overall structure of its capsid.

    PubMed

    Loison, Pauline; Majou, Didier; Gelhaye, Eric; Boudaud, Nicolas; Gantzer, Christophe

    2016-11-01

    phages infect Escherichia coli in the human gut by recognizing F-pili as receptors. Infection therefore occurs under reducing conditions induced by physiological agents (e.g. glutathione) or the intestinal bacterial flora. After excretion in the environment, phage particles are exposed to oxidizing conditions and sometimes disinfection. If inactivation does not occur, the phage may infect new hosts in the human gut through the oral route. During such a life cycle, we demonstrated that, outside the human gut, cysteines of the major protein capsid of Qβ phage form disulfide bonds. Disinfection with NaClO does not allow overoxidation to occur. Such oxidation induces inactivation rather by irreversible damage to the minor proteins. In the presence of glutathione, most disulfide bonds are reduced, which slightly increases the capacity of the phage to infect E. coli in vitro Such reduction is reversible and barely alters infectivity of the phage. Reduction of all disulfide bonds by dithiothreitol leads to complete capsid destabilization. These data provide new insights into how the phages are impacted by oxidizing-reducing conditions outside their host cell and raises the possibility of the intervention of the redox during life cycle of the phage. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. The Relationship between Chlamydia trachomatis Genital Infection and Spontaneous Abortion.

    PubMed

    Ahmadi, Amjad; Khodabandehloo, Mazaher; Ramazanzadeh, Rashid; Farhadifar, Fariba; Roshani, Daem; Ghaderi, Ebrahim; Farhangi, Niloofar

    2016-01-01

    Chlamydia trachomatis is the etiology of most of sexually transmitted diseases. Colonization of C. trachomatis in the genital tract during early gestation has been associated with preterm birth, and preterm premature rupture of the membranes. The role of C. trachomatis on spontaneous abortion has not yet been proved completely. The aim of this study was to evaluate the frequency of C. trachomatis infection among pregnant women and its association with spontaneous abortion. This case-control study was conducted from August 2012 until January 2013. Totally, 218 women were included; 109 women with spontaneous abortion with gestation age between 10-20 weeks (cases), and 109 women with normal pregnancy with gestation age between 20-30 weeks (controls) in Sanandaj, Iran. DNA was extracted from endocervical swabs and a PCR test was conducted for detection of C. trachomatis infection in women using specific primers. Independent T-test and Chi-square were used for comparison of quantitative and qualitative variables, respectively, and p<0.05 was considered significant. The total prevalence of C. trachomatis infection was 38(17.43%) in endocervical swabs of women. However, the number of cases with C. trachomatis infections was 25 out of 109(22.9%) in the case group and 13 out of 109(11.9%) in control group, respectively. Association between chlamydia infection and spontaneous abortion was statistically significant (OR=2.198, CI 95%: 1.058-4.56). Our study showed that C. trachomatis infection was associated with spontaneous abortion. Thus, screening and treatment of pregnant women may prevent this adverse pregnancy outcome.

  14. A field survey for Wolbchia and phage WO infections of Aedes albopictus in Guangzhou City, China.

    PubMed

    Zhang, Dongjing; Zhan, Ximei; Wu, Xiansheng; Yang, Xiao; Liang, Gehao; Zheng, Zhantu; Li, Zhuoya; Wu, Yu; Zheng, Xiaoying

    2014-01-01

    Wolbachia are maternal endosymbiotic bacterium, which infect a diverse range of arthropods, ranging from 20 to 76% in nature. They are capable of inducing a wide range of reproductive abnormalities to their hosts, such as cytoplasmic incompatibility (CI), which has been proposed to be used as a tool to modify mosquitoes that are resistant to the development of pathogen, as an alternative vector control strategy. Here, we evaluated the prevalence of Wolbachia and phage WO infections in the field population of Aedes albopictus in Guangzhou City via polymerase chain reaction (PCR) assay using the Wolbachia specific Wolbachia surface protein (wsp) and phage WO orf7 gene primers. Based on the results of PCR and phylogeny analysis, we found that A. albopictus in Guangzhou City were infected with two Wolbachia strains, wAlbA and wAlbB. Phage WO, the virus-infected Wolbachia, was also detected in A. albopictus. One hundred and ten female individuals were screened via PCR, with 109 super-infected with Wolbachia and one sample single-infected with wAlbB strain. And 104 of 113 male individuals were both infected with wAlbA and wAlbB, and nine male samples were found to be infected with wAlbA strain only. The infection rates of phage WO in female and male individuals were 82.73 and 46.02%, respectively. These results showed that the natural Wolbachia and phage WO infections in A. albopictus population in Guangzhou were at a higher frequency at present, indicating that Wolbachia appear to be a better candidate nature resource for biological control insect vectors to reduce vector-borne diseases.

  15. Competition between conjugation and M13 phage infection in Escherichia coli in the absence of selection pressure: a kinetic study.

    PubMed

    Wan, Zhenmao; Goddard, Noel L

    2012-10-01

    Inter- and intraspecies horizontal gene transfer enabled by bacterial secretion systems is a powerful mechanism for bacterial genome plasticity. The type IV secretion system of Escherichia coli, encoded by the F plasmid, enables cell-to-cell contact and subsequent DNA transfer known as conjugation. Conjugation is compromised by phage infection that specifically targets the secretion machinery. Hence, the use of phages to regulate the spread of genes, such as acquired antibiotic resistance or as general biosanitation agents, has gained interest. To predict the potential efficacy, the competition kinetics must first be understood. Using quantitative PCR to enumerate genomic loci in a resource-limited batch culture, we quantify the infection kinetics of the nonlytic phage M13 and its impact on conjugation in the absence of selection pressure (isogenic set). Modeling the resulting experimental data reveals the cellular growth rate to be reduced to 60% upon phage infection. We also find a maximum phage infection rate of 3×10(-11) mL phage(-1) min(-1) which is only 1 order of magnitude slower than the maximum conjugation rate (3×10(-10) mL cell(-1) min(-1)), suggesting phages must be in significant abundance to be effective antagonists to horizontal gene transfer. In the regime where the number of susceptible cells (F(+)) and phages are equal upon initial infection, we observe the spread of the conjugative plasmid throughout the cell population despite phage infection, but only at 10% of the uninfected rate. This has interesting evolutionary implications, as even in the absence of selection pressure, cells maintain the ability to conjugate despite phage vulnerability and the associated growth consequences.

  16. Novel Phage Group Infecting Lactobacillus delbrueckii subsp. lactis, as Revealed by Genomic and Proteomic Analysis of Bacteriophage Ldl1

    PubMed Central

    Casey, Eoghan; Mahony, Jennifer; Neve, Horst; Noben, Jean-Paul; Dal Bello, Fabio

    2014-01-01

    Ldl1 is a virulent phage infecting the dairy starter Lactobacillus delbrueckii subsp. lactis LdlS. Electron microscopy analysis revealed that this phage exhibits a large head and a long tail and bears little resemblance to other characterized phages infecting Lactobacillus delbrueckii. In vitro propagation of this phage revealed a latent period of 30 to 40 min and a burst size of 59.9 ± 1.9 phage particles. Comparative genomic and proteomic analyses showed remarkable similarity between the genome of Ldl1 and that of Lactobacillus plantarum phage ATCC 8014-B2. The genomic and proteomic characteristics of Ldl1 demonstrate that this phage does not belong to any of the four previously recognized L. delbrueckii phage groups, necessitating the creation of a new group, called group e, thus adding to the knowledge on the diversity of phages targeting strains of this industrially important lactic acid bacterial species. PMID:25501478

  17. Novel phage group infecting Lactobacillus delbrueckii subsp. lactis, as revealed by genomic and proteomic analysis of bacteriophage Ldl1.

    PubMed

    Casey, Eoghan; Mahony, Jennifer; Neve, Horst; Noben, Jean-Paul; Dal Bello, Fabio; van Sinderen, Douwe

    2015-02-01

    Ldl1 is a virulent phage infecting the dairy starter Lactobacillus delbrueckii subsp. lactis LdlS. Electron microscopy analysis revealed that this phage exhibits a large head and a long tail and bears little resemblance to other characterized phages infecting Lactobacillus delbrueckii. In vitro propagation of this phage revealed a latent period of 30 to 40 min and a burst size of 59.9 +/- 1.9 phage particles. Comparative genomic and proteomic analyses showed remarkable similarity between the genome of Ldl1 and that of Lactobacillus plantarum phage ATCC 8014-B2. The genomic and proteomic characteristics of Ldl1 demonstrate that this phage does not belong to any of the four previously recognized L. delbrueckii phage groups, necessitating the creation of a new group, called group e, thus adding to the knowledge on the diversity of phages targeting strains of this industrially important lactic acid bacterial species.

  18. Transcription Profiling of Bacillus subtilis Cells Infected with AR9, a Giant Phage Encoding Two Multisubunit RNA Polymerases.

    PubMed

    Lavysh, Daria; Sokolova, Maria; Slashcheva, Marina; Förstner, Konrad U; Severinov, Konstantin

    2017-02-14

    Bacteriophage AR9 is a recently sequenced jumbo phage that encodes two multisubunit RNA polymerases. Here we investigated the AR9 transcription strategy and the effect of AR9 infection on the transcription of its host, Bacillus subtilis Analysis of whole-genome transcription revealed early, late, and continuously expressed AR9 genes. Alignment of sequences upstream of the 5' ends of AR9 transcripts revealed consensus sequences that define early and late phage promoters. Continuously expressed AR9 genes have both early and late promoters in front of them. Early AR9 transcription is independent of protein synthesis and must be determined by virion RNA polymerase injected together with viral DNA. During infection, the overall amount of host mRNAs is significantly decreased. Analysis of relative amounts of host transcripts revealed notable differences in the levels of some mRNAs. The physiological significance of up- or downregulation of host genes for AR9 phage infection remains to be established. AR9 infection is significantly affected by rifampin, an inhibitor of host RNA polymerase transcription. The effect is likely caused by the antibiotic-induced killing of host cells, while phage genome transcription is solely performed by viral RNA polymerases. IMPORTANCE Phages regulate the timing of the expression of their own genes to coordinate processes in the infected cell and maximize the release of viral progeny. Phages also alter the levels of host transcripts. Here we present the results of a temporal analysis of the host and viral transcriptomes of Bacillus subtilis infected with a giant phage, AR9. We identify viral promoters recognized by two virus-encoded RNA polymerases that are a unique feature of the phiKZ-related group of phages to which AR9 belongs. Our results set the stage for future analyses of highly unusual RNA polymerases encoded by AR9 and other phiKZ-related phages. Copyright © 2017 Lavysh et al.

  19. Phage applications for improving food safety and infection control in Egypt.

    PubMed

    El-Shibiny, A; El-Sahhar, S; Adel, M

    2017-08-01

    The study investigated the use of bacteriophages to control bacterial contamination of chicken skin, eggs, tomatoes and meat. Experiments were performed to test the host ranges and killing potential of two isolated phages, ZCSE1 and ZCEC1, with hosts Salmonella and Escherichia coli respectively. The efficacy of both phages was determined by comparing the viable counts of recovered bacteria from treatment and phage-free control samples. In vitro experiments showed that phage ZCSE1 was able to reduce the numbers of Salmonella enterica ATCC 25566 to below 4·0 log 10 CFU per ml (3·4 log 10 CFU per ml reduction) in 240 min postinfection and phage ZCEC1 reduced the number of E. coli ATCC 8739 to undetectable levels (6·45 log 10 CFU per ml reduction) during the first hour of infection at 37°C. When applied to chicken skin and the surface of eggs, phage ZCSE1 treatment reduced the number of S. enterica ATCC 25566 by 2 log 10 and to undetectable levels (<2·0 log 10 CFU per ml), for skin and eggs respectively (P < 0·005). The administration of ZCEC1 phage to meat and tomatoes reduced the number of E. coli to below 2·0 log 10 CFU per ml 1 day after treatment. The administration of these phages to meat and tomatoes reduced the numbers of E. coli and Salmonella significantly in tested foods. The results suggest that phages could be effective treatments for pathogenic bacteria in food relevant contexts in Egypt. © 2017 The Society for Applied Microbiology.

  20. Development of Anti-Infectives Using Phage Display: Biological Agents against Bacteria, Viruses, and Parasites

    PubMed Central

    Huang, Johnny X.; Bishop-Hurley, Sharon L.

    2012-01-01

    The vast majority of anti-infective therapeutics on the market or in development are small molecules; however, there is now a nascent pipeline of biological agents in development. Until recently, phage display technologies were used mainly to produce monoclonal antibodies (MAbs) targeted against cancer or inflammatory disease targets. Patent disputes impeded broad use of these methods and contributed to the dearth of candidates in the clinic during the 1990s. Today, however, phage display is recognized as a powerful tool for selecting novel peptides and antibodies that can bind to a wide range of antigens, ranging from whole cells to proteins and lipid targets. In this review, we highlight research that exploits phage display technology as a means of discovering novel therapeutics against infectious diseases, with a focus on antimicrobial peptides and antibodies in clinical or preclinical development. We discuss the different strategies and methods used to derive, select, and develop anti-infectives from phage display libraries and then highlight case studies of drug candidates in the process of development and commercialization. Advances in screening, manufacturing, and humanization technologies now mean that phage display can make a significant contribution in the fight against clinically important pathogens. PMID:22664969

  1. Development of anti-infectives using phage display: biological agents against bacteria, viruses, and parasites.

    PubMed

    Huang, Johnny X; Bishop-Hurley, Sharon L; Cooper, Matthew A

    2012-09-01

    The vast majority of anti-infective therapeutics on the market or in development are small molecules; however, there is now a nascent pipeline of biological agents in development. Until recently, phage display technologies were used mainly to produce monoclonal antibodies (MAbs) targeted against cancer or inflammatory disease targets. Patent disputes impeded broad use of these methods and contributed to the dearth of candidates in the clinic during the 1990s. Today, however, phage display is recognized as a powerful tool for selecting novel peptides and antibodies that can bind to a wide range of antigens, ranging from whole cells to proteins and lipid targets. In this review, we highlight research that exploits phage display technology as a means of discovering novel therapeutics against infectious diseases, with a focus on antimicrobial peptides and antibodies in clinical or preclinical development. We discuss the different strategies and methods used to derive, select, and develop anti-infectives from phage display libraries and then highlight case studies of drug candidates in the process of development and commercialization. Advances in screening, manufacturing, and humanization technologies now mean that phage display can make a significant contribution in the fight against clinically important pathogens.

  2. A Genetic Approach to the Development of New Therapeutic Phages to Fight Pseudomonas Aeruginosa in Wound Infections

    PubMed Central

    Krylov, Victor; Shaburova, Olga; Krylov, Sergey; Pleteneva, Elena

    2012-01-01

    Pseudomonas aeruginosa is a frequent participant in wound infections. Emergence of multiple antibiotic resistant strains has created significant problems in the treatment of infected wounds. Phage therapy (PT) has been proposed as a possible alternative approach. Infected wounds are the perfect place for PT applications, since the basic condition for PT is ensured; namely, the direct contact of bacteria and their viruses. Plenty of virulent (“lytic”) and temperate (“lysogenic”) bacteriophages are known in P. aeruginosa. However, the number of virulent phage species acceptable for PT and their mutability are limited. Besides, there are different deviations in the behavior of virulent (and temperate) phages from their expected canonical models of development. We consider some examples of non-canonical phage-bacterium interactions and the possibility of their use in PT. In addition, some optimal approaches to the development of phage therapy will be discussed from the point of view of a biologist, considering the danger of phage-assisted horizontal gene transfer (HGT), and from the point of view of a surgeon who has accepted the Hippocrates Oath to cure patients by all possible means. It is also time now to discuss the possible approaches in international cooperation for the development of PT. We think it would be advantageous to make phage therapy a kind of personalized medicine. PMID:23344559

  3. Characterization of Natronobacterium magadii phage phi Ch1, a unique archaeal phage containing DNA and RNA.

    PubMed

    Witte, A; Baranyi, U; Klein, R; Sulzner, M; Luo, C; Wanner, G; Krüger, D H; Lubitz, W

    1997-02-01

    A novel archaeal bacteriophage, phi Ch1, was isolated from a haloalkalophilic archaeon Natronobacterium magadii upon spontaneous lysis. The phage-cured strain N. magadii(L13) was used to demonstrate infectivity of phage phi Ch1. The turbid-plaque morphology and the fact that N. magadii cells isolated from plaques were able to produce phage indicated that phi Ch1 is a temperate phage. The phage morphology resembles other members of Myoviridae-infecting Halobacterium species. In solution below 2M NaCl, the phage lost its morphological stability and infectivity. One- and two-dimensional SDS-PAGE of phage particles revealed at least four major and five minor proteins with molecular masses ranging from 15 to 80 kDa and acidic isoelectric points. Southern blot analysis of chromosomal DNA of a lysogenic N. magadii strain showed that phi Ch1 exists as a chromosomally integrated prophage. The phage particles contain both double-stranded, linear DNA (approx. 55 kbp) as well as several RNA species (80-700 nucleotides). Hybridization of labelled RNA fragments to total DNA from N. magadii and phi Ch1 showed that the virion-associated RNA is host encoded. Part of the phage DNA population is modified and restriction analysis revealed evidence for adenine methylation. Phage phi Ch1 is the first virus described for the genus natronobacterium, and the first phage containing DNA and RNA in mature phage particles.

  4. Acute Rubella Virus Infection among Women with Spontaneous Abortion in Mwanza City, Tanzania.

    PubMed

    Lulandala, Lukombodzo; Mirambo, Mariam M; Matovelo, Dismas; Gumodoka, Balthazar; Mshana, Stephen E

    2017-03-01

    Acute rubella virus infection in early pregnancy has been associated with poor pregnancy outcome ranging from spontaneous abortion, stillbirth and multiple birth defects known as Congenital Rubella Syndrome (CRS). Despite its importance the prevalence of acute rubella virus infections is not known among women with spontaneous abortion in most centres in developing countries. The present study was aimed to determine the seroprevalence of acute rubella infection among women with spontaneous abortion in Mwanza city. A total of 268 women with spontaneous abortion were enrolled from four different hospitals in Mwanza city between November 2015 and April 2016. Blood samples were collected; sera were extracted and stored at -80°C until processing. Acute rubella virus infection was diagnosed by the detection of rubella specific IgM antibodies using indirect Enzyme Linked Immunosorbent Assay (ELISA) as per manufacturer's instructions. Data were analysed by using STATA version 11. The mean age of enrolled women was 26.3±5.6 years. The prevalence of acute rubella virus infection was found to be 9/268 (3.7%, 95% CI: 1-5). Only women residing in urban areas (AOR: 5.65, 95% CI: 1.15-27.77, p=0.035) were found to predict acute rubella virus infection among cases with spontaneous abortion in Mwanza city. About four out of hundred women residing in urban areas with spontaneous abortion in Mwanza are acutely infected with rubella virus highlighting the potential of this virus in contributing to poor pregnancy outcome in this setting.

  5. Acute Rubella Virus Infection among Women with Spontaneous Abortion in Mwanza City, Tanzania

    PubMed Central

    Lulandala, Lukombodzo; Matovelo, Dismas; Gumodoka, Balthazar; Mshana, Stephen E

    2017-01-01

    Introduction Acute rubella virus infection in early pregnancy has been associated with poor pregnancy outcome ranging from spontaneous abortion, stillbirth and multiple birth defects known as Congenital Rubella Syndrome (CRS). Despite its importance the prevalence of acute rubella virus infections is not known among women with spontaneous abortion in most centres in developing countries. Aim The present study was aimed to determine the seroprevalence of acute rubella infection among women with spontaneous abortion in Mwanza city. Materials and Methods A total of 268 women with spontaneous abortion were enrolled from four different hospitals in Mwanza city between November 2015 and April 2016. Blood samples were collected; sera were extracted and stored at -80°C until processing. Acute rubella virus infection was diagnosed by the detection of rubella specific IgM antibodies using indirect Enzyme Linked Immunosorbent Assay (ELISA) as per manufacturer’s instructions. Data were analysed by using STATA version 11. Results The mean age of enrolled women was 26.3±5.6 years. The prevalence of acute rubella virus infection was found to be 9/268 (3.7%, 95% CI: 1-5). Only women residing in urban areas (AOR: 5.65, 95% CI: 1.15-27.77, p=0.035) were found to predict acute rubella virus infection among cases with spontaneous abortion in Mwanza city. Conclusion About four out of hundred women residing in urban areas with spontaneous abortion in Mwanza are acutely infected with rubella virus highlighting the potential of this virus in contributing to poor pregnancy outcome in this setting. PMID:28511456

  6. The extracellular phage-host interactions involved in the bacteriophage LL-H infection of Lactobacillus delbrueckii ssp. lactis ATCC 15808

    PubMed Central

    Munsch-Alatossava, Patricia; Alatossava, Tapani

    2013-01-01

    The complete genome sequence of Lactobacillus bacteriophage LL-H was determined in 1996. Accordingly, LL-H has been used as a model phage for the infection of dairy Lactobacillus, specifically for thermophilic Lactobacillus delbrueckii ssp. lactis host strains, such as ATCC 15808. One of the major goals of phage LL-H research consisted of the characterization of the first phage-host interactions at the level of phage adsorption and phage DNA injection steps to determine effective and practical methods to minimize the risks associated with the appearance and attack of phages in the manufacture of yogurt, and Swiss or Italian hard type cheeses, which typically use thermophilic lactic acid bacteria starter cultures containing L. delbrueckii strains among others. This mini review article summarizes the present data concerning (i) the special features, particle structure, and components of phage LL-H and (ii) the structure and properties of lipoteichoic acids (LTAs), which are the phage LL-H receptor components of L. delbrueckii ssp. lactis host strains. Moreover, a model of the first, extracellular, phage-host interactions for the infection of L. delbrueckii ssp. lactis ATCC 15808 by phage LL-H is presented and further discussed. PMID:24400001

  7. The extracellular phage-host interactions involved in the bacteriophage LL-H infection of Lactobacillus delbrueckii ssp. lactis ATCC 15808.

    PubMed

    Munsch-Alatossava, Patricia; Alatossava, Tapani

    2013-12-24

    The complete genome sequence of Lactobacillus bacteriophage LL-H was determined in 1996. Accordingly, LL-H has been used as a model phage for the infection of dairy Lactobacillus, specifically for thermophilic Lactobacillus delbrueckii ssp. lactis host strains, such as ATCC 15808. One of the major goals of phage LL-H research consisted of the characterization of the first phage-host interactions at the level of phage adsorption and phage DNA injection steps to determine effective and practical methods to minimize the risks associated with the appearance and attack of phages in the manufacture of yogurt, and Swiss or Italian hard type cheeses, which typically use thermophilic lactic acid bacteria starter cultures containing L. delbrueckii strains among others. This mini review article summarizes the present data concerning (i) the special features, particle structure, and components of phage LL-H and (ii) the structure and properties of lipoteichoic acids (LTAs), which are the phage LL-H receptor components of L. delbrueckii ssp. lactis host strains. Moreover, a model of the first, extracellular, phage-host interactions for the infection of L. delbrueckii ssp. lactis ATCC 15808 by phage LL-H is presented and further discussed.

  8. Expert Opinion on Three Phage Therapy Related Topics: Bacterial Phage Resistance, Phage Training and Prophages in Bacterial Production Strains.

    PubMed

    Rohde, Christine; Resch, Grégory; Pirnay, Jean-Paul; Blasdel, Bob G; Debarbieux, Laurent; Gelman, Daniel; Górski, Andrzej; Hazan, Ronen; Huys, Isabelle; Kakabadze, Elene; Łobocka, Małgorzata; Maestri, Alice; Almeida, Gabriel Magno de Freitas; Makalatia, Khatuna; Malik, Danish J; Mašlaňová, Ivana; Merabishvili, Maia; Pantucek, Roman; Rose, Thomas; Štveráková, Dana; Van Raemdonck, Hilde; Verbeken, Gilbert; Chanishvili, Nina

    2018-04-05

    Phage therapy is increasingly put forward as a "new" potential tool in the fight against antibiotic resistant infections. During the "Centennial Celebration of Bacteriophage Research" conference in Tbilisi, Georgia on 26-29 June 2017, an international group of phage researchers committed to elaborate an expert opinion on three contentious phage therapy related issues that are hampering clinical progress in the field of phage therapy. This paper explores and discusses bacterial phage resistance, phage training and the presence of prophages in bacterial production strains while reviewing relevant research findings and experiences. Our purpose is to inform phage therapy stakeholders such as policy makers, officials of the competent authorities for medicines, phage researchers and phage producers, and members of the pharmaceutical industry. This brief also points out potential avenues for future phage therapy research and development as it specifically addresses those overarching questions that currently call for attention whenever phages go into purification processes for application.

  9. Expert Opinion on Three Phage Therapy Related Topics: Bacterial Phage Resistance, Phage Training and Prophages in Bacterial Production Strains

    PubMed Central

    Rohde, Christine; Resch, Grégory; Blasdel, Bob G.; Gelman, Daniel; Górski, Andrzej; Hazan, Ronen; Huys, Isabelle; Kakabadze, Elene; Łobocka, Małgorzata; Maestri, Alice; Makalatia, Khatuna; Malik, Danish J.; Mašlaňová, Ivana; Merabishvili, Maia; Rose, Thomas; Štveráková, Dana; Van Raemdonck, Hilde; Verbeken, Gilbert; Chanishvili, Nina

    2018-01-01

    Phage therapy is increasingly put forward as a “new” potential tool in the fight against antibiotic resistant infections. During the “Centennial Celebration of Bacteriophage Research” conference in Tbilisi, Georgia on 26–29 June 2017, an international group of phage researchers committed to elaborate an expert opinion on three contentious phage therapy related issues that are hampering clinical progress in the field of phage therapy. This paper explores and discusses bacterial phage resistance, phage training and the presence of prophages in bacterial production strains while reviewing relevant research findings and experiences. Our purpose is to inform phage therapy stakeholders such as policy makers, officials of the competent authorities for medicines, phage researchers and phage producers, and members of the pharmaceutical industry. This brief also points out potential avenues for future phage therapy research and development as it specifically addresses those overarching questions that currently call for attention whenever phages go into purification processes for application. PMID:29621199

  10. Phage Therapy: Eco-Physiological Pharmacology

    PubMed Central

    Abedon, Stephen T.

    2014-01-01

    Bacterial virus use as antibacterial agents, in the guise of what is commonly known as phage therapy, is an inherently physiological, ecological, and also pharmacological process. Physiologically we can consider metabolic properties of phage infections of bacteria and variation in those properties as a function of preexisting bacterial states. In addition, there are patient responses to pathogenesis, patient responses to phage infections of pathogens, and also patient responses to phage virions alone. Ecologically, we can consider phage propagation, densities, distribution (within bodies), impact on body-associated microbiota (as ecological communities), and modification of the functioning of body “ecosystems” more generally. These ecological and physiological components in many ways represent different perspectives on otherwise equivalent phenomena. Comparable to drugs, one also can view phages during phage therapy in pharmacological terms. The relatively unique status of phages within the context of phage therapy as essentially replicating antimicrobials can therefore result in a confluence of perspectives, many of which can be useful towards gaining a better mechanistic appreciation of phage therapy, as I consider here. Pharmacology more generally may be viewed as a discipline that lies at an interface between organism-associated phenomena, as considered by physiology, and environmental interactions as considered by ecology. PMID:25031881

  11. Acinetobacter phage genome is similar to Sphinx 2.36, the circular DNA copurified with TSE infected particles.

    PubMed

    Longkumer, Toshisangba; Kamireddy, Swetha; Muthyala, Venkateswar Reddy; Akbarpasha, Shaikh; Pitchika, Gopi Krishna; Kodetham, Gopinath; Ayaluru, Murali; Siddavattam, Dayananda

    2013-01-01

    While analyzing plasmids of Acinetobacter sp. DS002 we have detected a circular DNA molecule pTS236, which upon further investigation is identified as the genome of a phage. The phage genome has shown sequence similarity to the recently discovered Sphinx 2.36 DNA sequence co-purified with the Transmissible Spongiform Encephalopathy (TSE) particles isolated from infected brain samples collected from diverse geographical regions. As in Sphinx 2.36, the phage genome also codes for three proteins. One of them codes for RepA and is shown to be involved in replication of pTS236 through rolling circle (RC) mode. The other two translationally coupled ORFs, orf106 and orf96, code for coat proteins of the phage. Although an orf96 homologue was not previously reported in Sphinx 2.36, a closer examination of DNA sequence of Sphinx 2.36 revealed its presence downstream of orf106 homologue. TEM images and infection assays revealed existence of phage AbDs1 in Acinetobacter sp. DS002.

  12. Acinetobacter phage genome is similar to Sphinx 2.36, the circular DNA copurified with TSE infected particles

    PubMed Central

    Longkumer, Toshisangba; Kamireddy, Swetha; Muthyala, Venkateswar Reddy; Akbarpasha, Shaikh; Pitchika, Gopi Krishna; Kodetham, Gopinath; Ayaluru, Murali; Siddavattam, Dayananda

    2013-01-01

    While analyzing plasmids of Acinetobacter sp. DS002 we have detected a circular DNA molecule pTS236, which upon further investigation is identified as the genome of a phage. The phage genome has shown sequence similarity to the recently discovered Sphinx 2.36 DNA sequence co-purified with the Transmissible Spongiform Encephalopathy (TSE) particles isolated from infected brain samples collected from diverse geographical regions. As in Sphinx 2.36, the phage genome also codes for three proteins. One of them codes for RepA and is shown to be involved in replication of pTS236 through rolling circle (RC) mode. The other two translationally coupled ORFs, orf106 and orf96, code for coat proteins of the phage. Although an orf96 homologue was not previously reported in Sphinx 2.36, a closer examination of DNA sequence of Sphinx 2.36 revealed its presence downstream of orf106 homologue. TEM images and infection assays revealed existence of phage AbDs1 in Acinetobacter sp. DS002. PMID:23867905

  13. A proposed integrated approach for the preclinical evaluation of phage therapy in Pseudomonas infections

    NASA Astrophysics Data System (ADS)

    Danis-Wlodarczyk, Katarzyna; Vandenheuvel, Dieter; Jang, Ho Bin; Briers, Yves; Olszak, Tomasz; Arabski, Michal; Wasik, Slawomir; Drabik, Marcin; Higgins, Gerard; Tyrrell, Jean; Harvey, Brian J.; Noben, Jean-Paul; Lavigne, Rob; Drulis-Kawa, Zuzanna

    2016-06-01

    Bacteriophage therapy is currently resurging as a potential complement/alternative to antibiotic treatment. However, preclinical evaluation lacks streamlined approaches. We here focus on preclinical approaches which have been implemented to assess bacteriophage efficacy against Pseudomonas biofilms and infections. Laser interferometry and profilometry were applied to measure biofilm matrix permeability and surface geometry changes, respectively. These biophysical approaches were combined with an advanced Airway Surface Liquid infection model, which mimics in vitro the normal and CF lung environments, and an in vivo Galleria larvae model. These assays have been implemented to analyze KTN4 (279,593 bp dsDNA genome), a type-IV pili dependent, giant phage resembling phiKZ. Upon contact, KTN4 immediately disrupts the P. aeruginosa PAO1 biofilm and reduces pyocyanin and siderophore production. The gentamicin exclusion assay on NuLi-1 and CuFi-1 cell lines revealed the decrease of extracellular bacterial load between 4 and 7 logs and successfully prevents wild-type Pseudomonas internalization into CF epithelial cells. These properties and the significant rescue of Galleria larvae indicate that giant KTN4 phage is a suitable candidate for in vivo phage therapy evaluation for lung infection applications.

  14. Development of a Phage Cocktail to Control Proteus mirabilis Catheter-associated Urinary Tract Infections

    PubMed Central

    Melo, Luís D. R.; Veiga, Patrícia; Cerca, Nuno; Kropinski, Andrew M.; Almeida, Carina; Azeredo, Joana; Sillankorva, Sanna

    2016-01-01

    Proteus mirabilis is an enterobacterium that causes catheter-associated urinary tract infections (CAUTIs) due to its ability to colonize and form crystalline biofilms on the catheters surface. CAUTIs are very difficult to treat, since biofilm structures are highly tolerant to antibiotics. Phages have been used widely to control a diversity of bacterial species, however, a limited number of phages for P. mirabilis have been isolated and studied. Here we report the isolation of two novel virulent phages, the podovirus vB_PmiP_5460 and the myovirus vB_PmiM_5461, which are able to target, respectively, 16 of the 26 and all the Proteus strains tested in this study. Both phages have been characterized thoroughly and sequencing data revealed no traces of genes associated with lysogeny. To further evaluate the phages’ ability to prevent catheter’s colonization by Proteus, the phages adherence to silicone surfaces was assessed. Further tests in phage-coated catheters using a dynamic biofilm model simulating CAUTIs, have shown a significant reduction of P. mirabilis biofilm formation up to 168 h of catheterization. These results highlight the potential usefulness of the two isolated phages for the prevention of surface colonization by this bacterium. PMID:27446059

  15. Phages in nature

    PubMed Central

    Millard, Andrew D; Letarov, Andrey V; Heaphy, Shaun

    2011-01-01

    Bacteriophages or phages are the most abundant organisms in the biosphere and they are a ubiquitous feature of prokaryotic existence. A bacteriophage is a virus which infects a bacterium. Archaea are also infected by viruses, whether these should be referred to as ‘phages’ is debatable, but they are included as such in the scope this article. Phages have been of interest to scientists as tools to understand fundamental molecular biology, as vectors of horizontal gene transfer and drivers of bacterial evolution, as sources of diagnostic and genetic tools and as novel therapeutic agents. Unraveling the biology of phages and their relationship with their hosts is key to understanding microbial systems and their exploitation. In this article we describe the roles of phages in different host systems and show how modeling, microscopy, isolation, genomic and metagenomic based approaches have come together to provide unparalleled insights into these small but vital constituents of the microbial world. PMID:21687533

  16. Human papillomavirus infection and spontaneous abortion: a case-control study performed in Mexico.

    PubMed

    Conde-Ferráez, Laura; Chan May, Alberto de A; Carrillo-Martínez, Jorge R; Ayora-Talavera, Guadalupe; González-Losa, María del Refugio

    2013-10-01

    To investigate if HPV cervical infection is associated with spontaneous abortion in a Mexican population. Case control study including 281 women from two Social Security Hospitals in Merida, Mexico. Cases were women with spontaneous abortion attending for curettage, and controls were pregnant women at term who attended for delivery. HPV molecular detection and typing of HPV 16, 18, 58 and 6/11 was performed on cervical samples, and TORCH serology IgM tests (against T. gondii, CMV, HSV) were performed on cases. Data were analyzed using Chi square, odds ratio and linear regression tests. HPV global prevalence was 19.8% (24.4% in cases and 15.2% in controls). HPV types 16 and 58 were the most frequently detected in both groups. Multiple HPV types concurrent infection were found in 31.4% of typified samples. Amongst cases 27.3% of HPV positive women reported at least one previous pregnancy loss; compared to 17.43% amongst HPV negative women. Nevertheless, HPV was not significantly associated with spontaneous or to repetitive abortion. Cases were 60.2% positive to any TORCH agent, although it was not significantly associated to referred miscarriage history. Spontaneous abortion was associated to a previous pregnancy loss and to women's age older than 35 years old. HPV infection was significantly associated to alcohol intake before pregnancy and to multiple sexual partners. HPV cervical infection was not associated with spontaneous abortion. HPV in spontaneous abortion and other adverse pregnancy outcomes merits further study. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Case-control study of infections with Salmonella enteritidis phage type 4 in England.

    PubMed Central

    Cowden, J. M.; Lynch, D.; Joseph, C. A.; O'Mahony, M.; Mawer, S. L.; Rowe, B.; Bartlett, C. L.

    1989-01-01

    OBJECTIVE--To determine the source of indigenous sporadic infection with Salmonella enteritidis phage type 4. DESIGN--Case-control study of primary sporadic cases identified by the Public Health Laboratory Service between 1 August and 30 September 1988. SETTING--PHLS Communicable Disease Surveillance Centre, Division of Enteric Pathogens, 11 PHLS laboratories, and 42 local authority environmental health departments in England. SUBJECTS--232 Patients (cases) with confirmed primary sporadic infection, for 160 of whom (88 female) (median age 30 years, age range 4 months to 85 years) data were obtained by questionnaire about consumption of fresh eggs, egg products, precooked chicken, and minced meat in the three days and one week before onset of the symptoms. Up to three controls, matched for neighbourhood, age, and sex (if aged greater than 11 years), were asked the same questions for the same calendar period. MAIN OUTCOME MEASURE--Association of primary sporadic infection with consumption of suspected food items. RESULTS--Illness due to S enteritidis phage type 4 was significantly associated with consumption of raw shell egg products (homemade mayonnaise, ice cream, and milk drinks containing eggs) (matched p = 0.02) and shop bought sandwiches containing mayonnaise (matched p = 0.00004) or eggs (matched p = 0.02). Illness was also significantly associated with eating lightly cooked eggs (unmatched p = 0.02), but not soft boiled eggs, and precooked hot chicken (matched p = 0.006). Reported consumption of eggs was not appreciably different between cases and controls before or after the median date of interview. CONCLUSIONS--Fresh shell eggs, egg products, and precooked hot chicken are vehicles of S enteritidis phage type 4 infection in indigenous sporadic cases. Public health education and reduction in contamination of eggs and infection of poultry with S enteritidis are needed to reduce the incidence of human infection. PMID:2508916

  18. Characterization of Two Virulent Phages of Lactobacillus plantarum

    PubMed Central

    Briggiler Marcó, Mariángeles; Garneau, Josiane E.; Tremblay, Denise; Quiberoni, Andrea

    2012-01-01

    We characterized two Lactobacillus plantarum virulent siphophages, ATCC 8014-B1 (B1) and ATCC 8014-B2 (B2), previously isolated from corn silage and anaerobic sewage sludge, respectively. Phage B2 infected two of the eight L. plantarum strains tested, while phage B1 infected three. Phage adsorption was highly variable depending on the strain used. Phage defense systems were found in at least two L. plantarum strains, LMG9211 and WCSF1. The linear double-stranded DNA genome of the pac-type phage B1 had 38,002 bp, a G+C content of 47.6%, and 60 open reading frames (ORFs). Surprisingly, the phage B1 genome has 97% identity with that of Pediococcus damnosus phage clP1 and 77% identity with that of L. plantarum phage JL-1; these phages were isolated from sewage and cucumber fermentation, respectively. The double-stranded DNA (dsDNA) genome of the cos-type phage B2 had 80,618 bp, a G+C content of 36.9%, and 127 ORFs with similarities to those of Bacillus and Lactobacillus strains as well as phages. Some phage B2 genes were similar to ORFs from L. plantarum phage LP65 of the Myoviridae family. Additionally, 6 tRNAs were found in the phage B2 genome. Protein analysis revealed 13 (phage B1) and 9 (phage B2) structural proteins. To our knowledge, this is the first report describing such high identity between phage genomes infecting different genera of lactic acid bacteria. PMID:23042172

  19. Reduction in Infection-Related Mortality since Modifications in the Regimen of Medical Abortion

    PubMed Central

    Trussell, James; Nucatola, Deborah; Fjerstad, Mary; Lichtenberg, E Steve

    2014-01-01

    Background From 2001 to March 2006 Planned Parenthood health centers throughout the United States provided medical abortion by a regimen of oral mifepristone followed 24 to 48 hours later by vaginal misoprostol. In response to concerns about serious infections, in early 2006 Planned Parenthood changed the route of misoprostol administration to buccal and required either routine antibiotic coverage or universal screening and treatment for chlamydia; in July 2007, Planned Parenthood began requiring routine antibiotic coverage for all medical abortions. Methods We performed a retrospective analysis of Planned Parenthood cases assessing the rates of mortality caused by infection following medical abortion during a time period when misoprostol was administered vaginally (2001 through March 2006), as compared with the rate from April 2006 to the end of 2012 after a change to buccal administration of misoprostol and after initiation of new infection-reduction strategies. Results The mortality rate dropped significantly in the 81-month period after the joint change to 1) buccal misoprostol replacing vaginal misoprostol and 2) either sexually transmitted infection (STI) screening or routine preventative antibiotic coverage (15 month period) or universal routine preventative antibiotic coverage as part of the medical abortion (66 month period), from 1.37/100,000 to 0.00/100,000, p=0.013 (difference=1.37/100,000, 95% CI 0.47-4.03 per 100,000). Conclusion The infection-caused mortality rate following medical abortion declined by 100% following a change from vaginal to buccal administration of misoprostol combined with screen-and-treat or, far more commonly, routine antibiotic coverage. PMID:24405798

  20. A novel helper phage enabling construction of genome-scale ORF-enriched phage display libraries.

    PubMed

    Gupta, Amita; Shrivastava, Nimisha; Grover, Payal; Singh, Ajay; Mathur, Kapil; Verma, Vaishali; Kaur, Charanpreet; Chaudhary, Vijay K

    2013-01-01

    Phagemid-based expression of cloned genes fused to the gIIIP coding sequence and rescue using helper phages, such as VCSM13, has been used extensively for constructing large antibody phage display libraries. However, for randomly primed cDNA and gene fragment libraries, this system encounters reading frame problems wherein only one of 18 phages display the translated foreign peptide/protein fused to phagemid-encoded gIIIP. The elimination of phages carrying out-of-frame inserts is vital in order to improve the quality of phage display libraries. In this study, we designed a novel helper phage, AGM13, which carries trypsin-sensitive sites within the linker regions of gIIIP. This renders the phage highly sensitive to trypsin digestion, which abolishes its infectivity. For open reading frame (ORF) selection, the phagemid-borne phages are rescued using AGM13, so that clones with in-frame inserts express fusion proteins with phagemid-encoded trypsin-resistant gIIIP, which becomes incorporated into the phages along with a few copies of AGM13-encoded trypsin-sensitive gIIIP. In contrast, clones with out-of-frame inserts produce phages carrying only AGM13-encoded trypsin-sensitive gIIIP. Trypsin treatment of the phage population renders the phages with out-of-frame inserts non-infectious, whereas phages carrying in-frame inserts remain fully infectious and can hence be enriched by infection. This strategy was applied efficiently at a genome scale to generate an ORF-enriched whole genome fragment library from Mycobacterium tuberculosis, in which nearly 100% of the clones carried in-frame inserts after selection. The ORF-enriched libraries were successfully used for identification of linear and conformational epitopes for monoclonal antibodies specific to mycobacterial proteins.

  1. Survey on association between Mycoplasma hominis endocervical infection and spontaneous abortion using Polymerase Chain Reaction.

    PubMed

    Farhadifar, Fariba; Khodabandehloo, Mazaher; Ramazanzadeh, Rashid; Rouhi, Samaneh; Ahmadi, Amjad; Ghaderi, Ebrahim; Roshani, Daem; Soofizadeh, Nasrin; Rezzaii, Masoomeh

    2016-03-01

    Mycoplasma infections are suggested as etiology of adverse pregnancy outcomes. The aim of this study was to evaluate the association of Mycoplasma hominis (M. hominis) infection and spontaneous abortion among pregnant women. In this case-control study that was conducted from August 2012 to January 2013, totally, 109 women were included with spontaneous abortion with gestational ages of 10-20 weeks (Cases), and 109 women with normal pregnancy with gestational ages between 20-37 weeks (Controls) in Sanandaj, Iran. Using specific primers and extracted DNA from endocervical swabs, a PCR test was conducted for detection of M. hominis infection in women. For comparison of qualitative and quantitative variables, independent Fisher tests were used and p<0.05 was considered significant. The total frequency of M. hominis infection was 6 (2.75%) in women. The frequency of M. hominis infection was 2 (1.83%) in the case group (spontaneous abortion) and 4 (3.66%) in the control group, respectively. In both case and control groups, no association was seen between M.hominis infection and spontaneous abortion (OR=0. 49, CI 95%: 0.08-2.73, p=0. 683). M. hominis was positive in the genital tract of some pregnant women, but it was not associated with spontaneous abortion. However, to prevent adverse pregnancy outcomes in women, foetus and neonate, routine screening and treatment for the genital Mycoplasma is recommended.

  2. Dispersal and survival of Flavobacterium psychrophilum phages in vivo in rainbow trout and in vitro under laboratory conditions: implications for their use in phage therapy.

    PubMed

    Madsen, Lone; Bertelsen, Sif K; Dalsgaard, Inger; Middelboe, Mathias

    2013-08-01

    Attention has been drawn to phage therapy as an alternative approach for controlling pathogenic bacteria such as Flavobacterium psychrophilum in salmonid aquaculture, which can give rise to high mortalities, especially in rainbow trout fry. Recently, phages have been isolated with a broad host range and a strong lytic potential against pathogenic F. psychrophilum under experimental conditions. However, little is known about the fate of phages at environmental conditions. Here, we quantified the dispersal and fate of F. psychrophilum phages and hosts in rainbow trout fry after intraperitoneal injection. Both phages and bacteria were isolated from the fish organs for up to 10 days after injection, and coinjection with both bacteria and phages resulted in a longer persistence of the phage in the fish organs, than when the fish had been injected with the phages only. The occurrence of both phage and bacterium was most prevalent in the kidney and spleen, with only minor occurrence in the brain. The experiment showed that injected phages were rapidly spread in the internal organs of the fish, also in the absence of bacteria. Parallel examination of the regulation of bacteriophage infectivity in controlled laboratory experiments at various environmental conditions showed that pH had only minor effects on long-term (3 months) phage infectivity within a pH range of 4.5 to 7.5, whereas phage infectivity was immediately lost at pH 3. In the absence of host cells, phage infectivity decreased by a factor of 10,000 over 55 days in untreated pond water, while the sterilization and removal of particles caused a 100-fold increase in phage survival relative to the control. In addition, F. psychrophilum-specific phages maintained their infectivity for ∼2 months in glycerol at -80°C, whereas infectivity decreased by a factor 10 when kept in a buffer at 20°C. Only a very small degradation in infectivity was seen when bacteriophages were added and dried on fish feed pellets

  3. Infective and inactivated filamentous phage as carriers for immunogenic peptides.

    PubMed

    Samoylova, Tatiana I; Norris, Mandy D; Samoylov, Alexandre M; Cochran, Anna M; Wolfe, Karen G; Petrenko, Valery A; Cox, Nancy R

    2012-07-01

    The focus of this study is on development of vaccines using filamentous phage as a delivery vector for immunogenic peptides. The use of phage as a carrier for immunogenic peptides provides significant benefits such as high immunogenicity, low production costs, and high stability of phage preparations. However, introduction of live recombinant phage into the environment might represent a potential ecological problem. This, for example, may occur when vaccines are used in oral or nasal formulations in field conditions for wild and feral animals. To address this issue, comparative studies of antigenic properties of live and inactivated (non-viable) phage were accomplished. Inactivated phage, if released, will not propagate and will degrade as any other protein. In these experiments, a model phage clone that was previously selected from a phage display library and shown to stimulate production of anti-sperm antibodies with contraceptive properties was used. Multiple methods of phage inactivation were tested, including drying, freezing, autoclaving, heating, and UV irradiation. Under studied conditions, heating at 76°C for 3h, UV irradiation, and autoclaving resulted in complete phage inactivation. Phage samples treated by heat and UV were characterized by spectrophotometry and electron microscopy. To test antigenicity, live and inactivated phage preparations were injected into mice and antibody responses assayed by ELISA. It was found that phage killed by heat causes little to no immune responses, probably due to destruction of phage particles. In contrast, UV-inactivated phage stimulated production of IgG serum antibodies at the levels comparable to live phage. Thus, vaccines formulated to include UV-inactivated filamentous phage might represent environmentally safe alternatives to live phage vaccines. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Filamentous Phage: Structure and Biology.

    PubMed

    Rakonjac, Jasna; Russel, Marjorie; Khanum, Sofia; Brooke, Sam J; Rajič, Marina

    2017-01-01

    Ff filamentous phage (fd, M13 and f1) of Escherichia coli have been the workhorse of phage display technology for the past 30 years. Dominance of Ff over other bacteriophage in display technology stems from the titres that are about 100-fold higher than any other known phage, efficacious transformation ensuring large library size and superior stability of the virion at high temperatures, detergents and pH extremes, allowing broad range of biopanning conditions in screening phage display libraries. Due to the excellent understanding of infection and assembly requirements, Ff phage have also been at the core of phage-assisted continual protein evolution strategies (PACE). This chapter will give an overview of the Ff filamentous phage structure and biology, emphasizing those properties of the Ff phage life cycle and virion that are pertinent to phage display applications.

  5. Phages Infecting Vibrio vulnificus Are Abundant and Diverse in Oysters (Crassostrea virginica) Collected from the Gulf of Mexico

    PubMed Central

    DePaola, Angelo; Motes, Miles L.; Chan, Amy M.; Suttle, Curtis A.

    1998-01-01

    Phages infecting Vibrio vulnificus were abundant (>104 phages g of oyster tissue−1) throughout the year in oysters (Crassostrea virginica) collected from estuaries adjacent to the Gulf of Mexico (Apalachicola Bay, Fla.; Mobile Bay, Ala.; and Black Bay, La.). Estimates of abundance ranged from 101 to 105 phages g of oyster tissue−1 and were dependent on the bacterial strain used to assay the sample. V. vulnificus was near or below detection limits (<0.3 cell g−1) from January through March and was most abundant (103 to 104 cells g−1) during the summer and fall, when phage abundances also tended to be greatest. The phages isolated were specific to strains of V. vulnificus, except for one isolate that caused lysis in a few strains of V. parahaemolyticus. Based on morphological evidence obtained by transmission electron microscopy, the isolates belonged to the Podoviridae, Styloviridae, and Myoviridae, three families of double-stranded DNA phages. One newly described morphotype belonging to the Podoviridae appears to be ubiquitous in Gulf Coast oysters. Isolates of this morphotype have an elongated capsid (mean, 258 nm; standard deviation, 4 nm; n = 35), with some isolates having a relatively broad host range among strains of V. vulnificus. Results from this study indicate that a morphologically diverse group of phages which infect V. vulnificus is abundant and widely distributed in oysters from estuaries bordering the northeastern Gulf of Mexico. PMID:9435088

  6. Phage-displayed specific polypeptide antigens induce significant protective immunity against Trichinella spiralis infection in BALB/c mice.

    PubMed

    Cui, Jing; Ren, Hui Jun; Liu, Ruo Dan; Wang, Li; Zhang, Zi Fang; Wang, Zhong Quan

    2013-02-06

    Trichinellosis is a public health problem and is considered an emerging/re-emerging disease in various countries. The etiological agent of trichinellosis is the nematode Trichinella, which infects humans, domestic animals and wildlife. A veterinary vaccine could be an option to control the disease in domestic animals. Although several vaccine candidates have shown promising results, a vaccine against trichinellosis remains unavailable to date. Phage particles are especially ideal vaccine delivery vehicles because they do not interfere with the immune response against the displayed peptide antigens, and, if anything, are more likely to efficiently direct antigen expression to professional antigen-presenting cells. In this study, Tsp10 polypeptide, which was encoded by a cDNA fragment of Trichinella spiralis intestinal infective larvae and was found to bind to normal mouse intestinal cells, was displayed on the surface of T7 phage. Anti-Tsp10 antibodies were able to recognize the native Tsp10 protein mainly localized to the stichosome of T. spiralis. Mice immunized with the recombinant phage T7-Tsp10 showed a 62.8% reduction in adult worms and a 78.6% reduction in muscle larvae following challenge with T. spiralis muscle larvae. Our results demonstrate that the vaccination with Tsp10 polypeptide displayed by T7 phage elicits the Th2-predominant immune responses and produces a significant protection against T. spiralis infection in mice. These findings suggest that phage display is a simple, efficient, and promising tool to express candidate vaccine antigens for immunization against T. spiralis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Genomic Diversity of Phages Infecting Probiotic Strains of Lactobacillus paracasei

    PubMed Central

    Rousseau, Geneviève M.; Capra, María L.; Quiberoni, Andrea; Tremblay, Denise M.; Labrie, Simon J.

    2015-01-01

    Strains of the Lactobacillus casei group have been extensively studied because some are used as probiotics in foods. Conversely, their phages have received much less attention. We analyzed the complete genome sequences of five L. paracasei temperate phages: CL1, CL2, iLp84, iLp1308, and iA2. Only phage iA2 could not replicate in an indicator strain. The genome lengths ranged from 34,155 bp (iA2) to 39,474 bp (CL1). Phages iA2 and iLp1308 (34,176 bp) possess the smallest genomes reported, thus far, for phages of the L. casei group. The GC contents of the five phage genomes ranged from 44.8 to 45.6%. As observed with many other phages, their genomes were organized as follows: genes coding for DNA packaging, morphogenesis, lysis, lysogeny, and replication. Phages CL1, CL2, and iLp1308 are highly related to each other. Phage iLp84 was also related to these three phages, but the similarities were limited to gene products involved in DNA packaging and structural proteins. Genomic fragments of phages CL1, CL2, iLp1308, and iLp84 were found in several genomes of L. casei strains. Prophage iA2 is unrelated to these four phages, but almost all of its genome was found in at least four L. casei strains. Overall, these phages are distinct from previously characterized Lactobacillus phages. Our results highlight the diversity of L. casei phages and indicate frequent DNA exchanges between phages and their hosts. PMID:26475105

  8. Protein Expression Modifications in Phage-Resistant Mutants of Aeromonas salmonicida after AS-A Phage Treatment

    PubMed Central

    Osório, Nádia; Pereira, Carla; Simões, Sara; Delgadillo, Ivonne

    2018-01-01

    The occurrence of infections by pathogenic bacteria is one of the main sources of financial loss for the aquaculture industry. This problem often cannot be solved with antibiotic treatment or vaccination. Phage therapy seems to be an alternative environmentally-friendly strategy to control infections. Recognizing the cellular modifications that bacteriophage therapy may cause to the host is essential in order to confirm microbial inactivation, while understanding the mechanisms that drive the development of phage-resistant strains. The aim of this work was to detect cellular modifications that occur after phage AS-A treatment in A. salmonicida, an important fish pathogen. Phage-resistant and susceptible cells were subjected to five successive streak-plating steps and analysed with infrared spectroscopy, a fast and powerful tool for cell study. The spectral differences of both populations were investigated and compared with a phage sensitivity profile, obtained through the spot test and efficiency of plating. Changes in protein associated peaks were found, and these results were corroborated by 1-D electrophoresis of intracellular proteins analysis and by phage sensitivity profiles. Phage AS-A treatment before the first streaking-plate step clearly affected the intracellular proteins expression levels of phage-resistant clones, altering the expression of distinct proteins during the subsequent five successive streak-plating steps, making these clones recover and be phenotypically more similar to the sensitive cells. PMID:29518018

  9. Envisaging bacteria as phage targets

    PubMed Central

    Abedon, Stephen T.

    2011-01-01

    It can be difficult to appreciate just how small bacteria and phages are or how large, in comparison, the volumes that they occupy. A single milliliter, for example, can represent to a phage what would be, with proper scaling, an “ocean” to you and me. Here I illustrate, using more easily visualized macroscopic examples, the difficulties that a phage, as a randomly diffusing particle, can have in locating bacteria to infect. I conclude by restating the truism that the rate of phage adsorption to a given target bacterium is a function of phage density, that is, titer, in combination with the degree of bacterial susceptibility to adsorption by an encountering phage. PMID:23616932

  10. Three novel Pseudomonas phages isolated from composting provide insights into the evolution and diversity of tailed phages.

    PubMed

    Amgarten, Deyvid; Martins, Layla Farage; Lombardi, Karen Cristina; Antunes, Luciana Principal; de Souza, Ana Paula Silva; Nicastro, Gianlucca Gonçalves; Kitajima, Elliott Watanabe; Quaggio, Ronaldo Bento; Upton, Chris; Setubal, João Carlos; da Silva, Aline Maria

    2017-05-04

    Among viruses, bacteriophages are a group of special interest due to their capacity of infecting bacteria that are important for biotechnology and human health. Composting is a microbial-driven process in which complex organic matter is converted into humus-like substances. In thermophilic composting, the degradation activity is carried out primarily by bacteria and little is known about the presence and role of bacteriophages in this process. Using Pseudomonas aeruginosa as host, we isolated three new phages from a composting operation at the Sao Paulo Zoo Park (Brazil). One of the isolated phages is similar to Pseudomonas phage Ab18 and belongs to the Siphoviridae YuA-like viral genus. The other two isolated phages are similar to each other and present genomes sharing low similarity with phage genomes in public databases; we therefore hypothesize that they belong to a new genus in the Podoviridae family. Detailed genomic descriptions and comparisons of the three phages are presented, as well as two new clusters of phage genomes in the Viral Orthologous Clusters database of large DNA viruses. We found sequences encoding homing endonucleases that disrupt a putative ribonucleotide reductase gene and an RNA polymerase subunit 2 gene in two of the phages. These findings provide insights about the evolution of two-subunits RNA polymerases and the possible role of homing endonucleases in this process. Infection tests on 30 different strains of bacteria reveal a narrow host range for the three phages, restricted to P. aeruginosa PA14 and three other P. aeruginosa clinical isolates. Biofilm dissolution assays suggest that these phages could be promising antimicrobial agents against P. aeruginosa PA14 infections. Analyses on composting metagenomic and metatranscriptomic data indicate association between abundance variations in both phage and host populations in the environment. The results about the newly discovered and described phages contribute to the understanding of

  11. Stumbling across the Same Phage: Comparative Genomics of Widespread Temperate Phages Infecting the Fish Pathogen Vibrio anguillarum

    PubMed Central

    Kalatzis, Panos G.; Rørbo, Nanna; Castillo, Daniel; Mauritzen, Jesper Juel; Jørgensen, Jóhanna; Kokkari, Constantina; Zhang, Faxing; Katharios, Pantelis; Middelboe, Mathias

    2017-01-01

    Nineteen Vibrio anguillarum-specific temperate bacteriophages isolated across Europe and Chile from aquaculture and environmental sites were genome sequenced and analyzed for host range, morphology and life cycle characteristics. The phages were classified as Siphoviridae with genome sizes between 46,006 and 54,201 bp. All 19 phages showed high genetic similarity, and 13 phages were genetically identical. Apart from sporadically distributed single nucleotide polymorphisms (SNPs), genetic diversifications were located in three variable regions (VR1, VR2 and VR3) in six of the phage genomes. Identification of specific genes, such as N6-adenine methyltransferase and lambda like repressor, as well as the presence of a tRNAArg, suggested a both mutualistic and parasitic interaction between phages and hosts. During short term phage exposure experiments, 28% of a V. anguillarum host population was lysogenized by the temperate phages and a genomic analysis of a collection of 31 virulent V. anguillarum showed that the isolated phages were present as prophages in >50% of the strains covering large geographical distances. Further, phage sequences were widely distributed among CRISPR-Cas arrays of publicly available sequenced Vibrios. The observed distribution of these specific temperate Vibriophages across large geographical scales may be explained by efficient dispersal of phages and bacteria in the marine environment combined with a mutualistic interaction between temperate phages and their hosts which selects for co-existence rather than arms race dynamics. PMID:28531104

  12. A leucine repeat motif in AbiA is required for resistance of Lactococcus lactis to phages representing three species.

    PubMed

    Dinsmore, P K; O'Sullivan, D J; Klaenhammer, T R

    1998-05-28

    The abiA gene encodes an abortive bacteriophage infection mechanism that can protect Lactococcus species from infection by a variety of bacteriophages including three unrelated phage species. Five heptad leucine repeats suggestive of a leucine zipper motif were identified between residues 232 and 266 in the predicted amino acid sequence of the AbiA protein. The biological role of residues in the repeats was investigated by incorporating amino acid substitutions via site-directed mutagenesis. Each mutant was tested for phage resistance against three phages, phi 31, sk1, and c2, belonging to species P335, 936, and c2, respectively. The five residues that comprise the heptad repeats were designated L234, L242, A249, L256, and L263. Three single conservative mutations of leucine to valine in positions L235, L242, and L263 and a double mutation of two leucines (L235 and L242) to valines did not affect AbiA activity on any phages tested. Non-conservative single substitutions of charged amino acids for three of the leucines (L235, L242, and L256) virtually eliminated AbiA activity on all phages tested. Substitution of the alanine residue in the third repeat (A249) with a charged residue did not affect AbiA activity. Replacement of L242 with an alanine elimination phage resistance against phi 31, but partial resistance to sk1 and c2 remained. Two single proline substitutions for leucines L242 and L263 virtually eliminated AbiA activity against all phages, indicating that the predicted alpha-helical structure of this region is important. Mutations in an adjacent region of basic amino acids had various effects on phage resistance, suggesting that these basic residues are also important for AbiA activity. This directed mutagenesis analysis of AbiA indicated that the leucine repeat structure is essential for conferring phage resistance against three species of lactococcal bacteriophages.

  13. Injected phage-displayed-VP28 vaccine reduces shrimp Litopenaeus vannamei mortality by white spot syndrome virus infection.

    PubMed

    Solís-Lucero, G; Manoutcharian, K; Hernández-López, J; Ascencio, F

    2016-08-01

    White spot syndrome virus (WSSV) is the most important viral pathogen for the global shrimp industry causing mass mortalities with huge economic losses. Recombinant phages are capable of expressing foreign peptides on viral coat surface and act as antigenic peptide carriers bearing a phage-displayed vaccine. In this study, the full-length VP28 protein of WSSV, widely known as potential vaccine against infection in shrimp, was successfully cloned and expressed on M13 filamentous phage. The functionality and efficacy of this vaccine immunogen was demonstrated through immunoassay and in vivo challenge studies. In ELISA assay phage-displayed VP28 was bind to Litopenaeus vannamei immobilized hemocyte in contrast to wild-type M13 phage. Shrimps were injected with 2 × 10(10) cfu animal(-1) single dose of VP28-M13 and M13 once and 48 h later intramuscularly challenged with WSSV to test the efficacy of the vaccine against the infection. All dead challenged shrimps were PCR WSSV-positive. The accumulative mortality of the vaccinated and challenged shrimp groups was significantly lower (36.67%) than the unvaccinated group (66.67%). Individual phenoloxidase and superoxide dismutase activity was assayed on 8 and 48 h post-vaccination. No significant difference was found in those immunological parameters among groups at any sampled time evaluated. For the first time, phage display technology was used to express a recombinant vaccine for shrimp. The highest percentage of relative survival in vaccinated shrimp (RPS = 44.99%) suggest that the recombinant phage can be used successfully to display and deliver VP28 for farmed marine crustaceans. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Clostridium difficile phages: still difficult?

    PubMed Central

    Hargreaves, Katherine R.; Clokie, Martha R. J.

    2014-01-01

    Phages that infect Clostridium difficile were first isolated for typing purposes in the 1980s, but their use was short lived. However, the rise of C. difficile epidemics over the last decade has triggered a resurgence of interest in using phages to combat this pathogen. Phage therapy is an attractive treatment option for C. difficile infection, however, developing suitable phages is challenging. In this review we summarize the difficulties faced by researchers in this field, and we discuss the solutions and strategies used for the development of C. difficile phages for use as novel therapeutics. Epidemiological data has highlighted the diversity and distribution of C. difficile, and shown that novel strains continue to emerge in clinical settings. In parallel with epidemiological studies, advances in molecular biology have bolstered our understanding of C. difficile biology, and our knowledge of phage–host interactions in other bacterial species. These three fields of biology have therefore paved the way for future work on C. difficile phages to progress and develop. Benefits of using C. difficile phages as therapeutic agents include the fact that they have highly specific interactions with their bacterial hosts. Studies also show that they can reduce bacterial numbers in both in vitro and in vivo systems. Genetic analysis has revealed the genomic diversity among these phages and provided an insight into their taxonomy and evolution. No strictly virulent C. difficile phages have been reported and this contributes to the difficulties with their therapeutic exploitation. Although treatment approaches using the phage-encoded endolysin protein have been explored, the benefits of using “whole-phages” are such that they remain a major research focus. Whilst we don’t envisage working with C. difficile phages will be problem-free, sufficient study should inform future strategies to facilitate their development to combat this problematic pathogen. PMID:24808893

  15. Bacteriophages and Phage-Derived Proteins – Application Approaches

    PubMed Central

    Drulis-Kawa, Zuzanna; Majkowska-Skrobek, Grazyna; Maciejewska, Barbara

    2015-01-01

    Currently, the bacterial resistance, especially to most commonly used antibiotics has proved to be a severe therapeutic problem. Nosocomial and community-acquired infections are usually caused by multidrug resistant strains. Therefore, we are forced to develop an alternative or supportive treatment for successful cure of life-threatening infections. The idea of using natural bacterial pathogens such as bacteriophages is already well known. Many papers have been published proving the high antibacterial efficacy of lytic phages tested in animal models as well as in the clinic. Researchers have also investigated the application of non-lytic phages and temperate phages, with promising results. Moreover, the development of molecular biology and novel generation methods of sequencing has opened up new possibilities in the design of engineered phages and recombinant phage-derived proteins. Encouraging performances were noted especially for phage enzymes involved in the first step of viral infection responsible for bacterial envelope degradation, named depolymerases. There are at least five major groups of such enzymes – peptidoglycan hydrolases, endosialidases, endorhamnosidases, alginate lyases and hyaluronate lyases – that have application potential. There is also much interest in proteins encoded by lysis cassette genes (holins, endolysins, spanins) responsible for progeny release during the phage lytic cycle. In this review, we discuss several issues of phage and phage-derived protein application approaches in therapy, diagnostics and biotechnology in general. PMID:25666799

  16. Use of phages to control Vibrio splendidus infection in the juvenile sea cucumber Apostichopus japonicus.

    PubMed

    Li, Zhen; Li, Xiaoyu; Zhang, Jiancheng; Wang, Xitao; Wang, Lili; Cao, Zhenhui; Xu, Yongping

    2016-07-01

    , ingestion rate or feed conversion among sea cucumber fed the 4 phage treatments compared with those fed the unsupplemented diet (P > 0.05). The levels of nitric oxide synthase and acid phosphatase of sea cucumbers fed phage-containing diets were significantly (P < 0.05) increased compared with those fed the control diet. However, no significant differences (P > 0.05) were detected among the 4 phage-fed treatments. An additional study was conducted in which 60 healthy sea cucumbers (23 ± 2 g) were randomly assigned to a control, an untreated group and a test group to investigate the effects of injecting phages by coelomic injection on the survival rate and enzyme activities in the coelomic fluid of the sea cucumbers. The control was injected with 1 ml of sterilized seawater while the untreated group and the test group were injected with the same volume of V. splendidus-ABTNL culture (3 × 10(5) CFU/mL). Then, the test group was injected with 1 ml of the 3 phage cocktail (MOI = 10). After 48 h, the activities of lysozyme, acid phosphatase and superoxide dismutase were elevated in the untreated group while the levels of these enzymes in the test group were similar to the blank control. After 10-day observation, the survival rate of the sea cucumber was 100% for the blank control, 80% for the test group and 20% for the negative control. The overall results of this experiment indicate that phage therapy increased the survival of sea cucumber infected with V. splendidus VS-ABTNL. The above results demonstrate that using phages, especially a combination of different phages, may be a feasible way to control Vibrio infection in the sea cucumber industry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Use of phages to control Campylobacter spp.

    PubMed

    Janež, Nika; Loc-Carrillo, Catherine

    2013-10-01

    The use of phages to control pathogenic bacteria has been investigated since they were first discovered in the beginning of the 1900s. Over the last century we have slowly gained an in-depth understanding of phage biology including which phage properties are desirable when considering phage as biocontrol agents and which phage characteristics to potentially avoid. Campylobacter infections are amongst the most frequently encountered foodborne bacterial infections around the world. Handling and consumption of raw or undercooked poultry products have been determined to be the main route of transmission. The ability to use phages to target these bacteria has been studied for more than a decade and although we have made progress towards deciphering how best to use phages to control Campylobacter associated with poultry production, there is still much work to be done. This review outlines methods to improve the isolation of these elusive phages, as well as methods to identify desirable characteristics needed for a successful outcome. It also highlights the body of research undertaken so far and what criteria to consider when doing in-vivo studies, especially because some in-vitro studies have not been found to translate into to phage efficacy in-vivo. © 2013. Published by Elsevier B.V. All rights reserved.

  18. Targeting Enterococcus faecalis Biofilms with Phage Therapy

    PubMed Central

    Khalifa, Leron; Brosh, Yair; Gelman, Daniel; Coppenhagen-Glazer, Shunit; Beyth, Shaul; Poradosu-Cohen, Ronit; Que, Yok-Ai; Beyth, Nurit

    2015-01-01

    Phage therapy has been proven to be more effective, in some cases, than conventional antibiotics, especially regarding multidrug-resistant biofilm infections. The objective here was to isolate an anti-Enterococcus faecalis bacteriophage and to evaluate its efficacy against planktonic and biofilm cultures. E. faecalis is an important pathogen found in many infections, including endocarditis and persistent infections associated with root canal treatment failure. The difficulty in E. faecalis treatment has been attributed to the lack of anti-infective strategies to eradicate its biofilm and to the frequent emergence of multidrug-resistant strains. To this end, an anti-E. faecalis and E. faecium phage, termed EFDG1, was isolated from sewage effluents. The phage was visualized by electron microscopy. EFDG1 coding sequences and phylogeny were determined by whole genome sequencing (GenBank accession number KP339049), revealing it belongs to the Spounavirinae subfamily of the Myoviridae phages, which includes promising candidates for therapy against Gram-positive pathogens. This analysis also showed that the EFDG1 genome does not contain apparent harmful genes. EFDG1 antibacterial efficacy was evaluated in vitro against planktonic and biofilm cultures, showing effective lytic activity against various E. faecalis and E. faecium isolates, regardless of their antibiotic resistance profile. In addition, EFDG1 efficiently prevented ex vivo E. faecalis root canal infection. These findings suggest that phage therapy using EFDG1 might be efficacious to prevent E. faecalis infection after root canal treatment. PMID:25662974

  19. Rapid, Multiplexed Microfluidic Phage Display

    DTIC Science & Technology

    2012-01-01

    affinity phage- displayed peptides for multiple targets in just a single round and without the need for bacterial infection. The chip is shown to be able...by bacterial titer and amplification, and at least two additional rounds of selection. After the final round of biopan- ning, eluted phage are grown on...agar plates, and individual plaques are selected for DNA characterization to determine the amino acid sequence of the phage-displayed peptides. While

  20. Characterization and adsorption of Lactobacillus virulent phage P1.

    PubMed

    Chen, X; Xi, Y; Zhang, H; Wang, Z; Fan, M; Liu, Y; Wu, W

    2016-09-01

    Bacteriophage infection of lactic acid bacteria is considered an important problem worldwide in the food fermentation industry, as it may produce low quality or unsafe foods, cause fermentation failure, and result in economic losses. To increase current knowledge on the properties of Lactobacillus virulent phages, we evaluated the effect of divalent cations, temperature, pH, and chloramphenicol on the adsorption ability of Lactobacillus virulent phage P1. Phage P1 was isolated from the abnormal fermentation liquid of Lactobacillus plantarum IMAU10120. The results showed that this phage belonged to the Siphoviridae family. The latent period of this phage was 45min, and the burst time was 90min. Burst size was 132.88±2.37 phage counts expressed per milliliter per infective center. This phage showed good tolerance at different temperatures, but incubation at 50°C only affected its adsorption. Adsorption rate reached a maximum value between 30 and 42°C. A high adsorption value of phage infectivity was obtained from pH 6 to 8. Moreover, calcium ions promoted and increased the adsorption capacity of phage P1, but magnesium ions had negative effects. Chloramphenicol had no effect on phage adsorption. This study increased current knowledge on the characterization and biological aspects of Lactobacillus virulent phages, and may provide some basic information that can be used to design successful antiphage strategies in the food industry. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  1. Genes Required for Free Phage Production are Essential for Pseudomonas aeruginosa Chronic Lung Infections.

    PubMed

    Lemieux, Andrée-Ann; Jeukens, Julie; Kukavica-Ibrulj, Irena; Fothergill, Joanne L; Boyle, Brian; Laroche, Jérôme; Tucker, Nicholas P; Winstanley, Craig; Levesque, Roger C

    2016-02-01

    The opportunistic pathogen Pseudomonas aeruginosa causes chronic lung infection in patients with cystic fibrosis. The Liverpool Epidemic Strain LESB58 is highly resistant to antibiotics, transmissible, and associated with increased morbidity and mortality. Its genome contains 6 prophages and 5 genomic islands. We constructed a polymerase chain reaction (PCR)-based signature-tagged mutagenesis library of 9216 LESB58 mutants and screened the mutants in a rat model of chronic lung infection. A total of 162 mutants were identified as defective for in vivo maintenance, with 11 signature-tagged mutagenesis mutants having insertions in prophage and genomic island genes. Many of these mutants showed both diminished virulence and reduced phage production. Transcription profiling by quantitative PCR and RNA-Seq suggested that disruption of these prophages had a widespread trans-acting effect on the transcriptome. This study demonstrates that temperate phages play a pivotal role in the establishment of infection through modulation of bacterial host gene expression. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  2. Sinorhizobium meliloti Phage ΦM9 Defines a New Group of T4 Superfamily Phages with Unusual Genomic Features but a Common T=16 Capsid

    PubMed Central

    Johnson, Matthew C.; Tatum, Kelsey B.; Lynn, Jason S.; Brewer, Tess E.; Lu, Stephen; Washburn, Brian K.

    2015-01-01

    ABSTRACT Relatively little is known about the phages that infect agriculturally important nitrogen-fixing rhizobial bacteria. Here we report the genome and cryo-electron microscopy structure of the Sinorhizobium meliloti-infecting T4 superfamily phage ΦM9. This phage and its close relative Rhizobium phage vB_RleM_P10VF define a new group of T4 superfamily phages. These phages are distinctly different from the recently characterized cyanophage-like S. meliloti phages of the ΦM12 group. Structurally, ΦM9 has a T=16 capsid formed from repeating units of an extended gp23-like subunit that assemble through interactions between one subunit and the adjacent E-loop insertion domain. Though genetically very distant from the cyanophages, the ΦM9 capsid closely resembles that of the T4 superfamily cyanophage Syn9. ΦM9 also has the same T=16 capsid architecture as the very distant phage SPO1 and the herpesviruses. Despite their overall lack of similarity at the genomic and structural levels, ΦM9 and S. meliloti phage ΦM12 have a small number of open reading frames in common that appear to encode structural proteins involved in interaction with the host and which may have been acquired by horizontal transfer. These proteins are predicted to encode tail baseplate proteins, tail fibers, tail fiber assembly proteins, and glycanases that cleave host exopolysaccharide. IMPORTANCE Despite recent advances in the phylogenetic and structural characterization of bacteriophages, only a small number of phages of plant-symbiotic nitrogen-fixing soil bacteria have been studied at the molecular level. The effects of phage predation upon beneficial bacteria that promote plant growth remain poorly characterized. First steps in understanding these soil bacterium-phage dynamics are genetic, molecular, and structural characterizations of these groups of phages. The T4 superfamily phages are among the most complex phages; they have large genomes packaged within an icosahedral head and a long

  3. Complete genomic sequences of Propionibacterium freudenreichii phages from Swiss cheese reveal greater diversity than Cutibacterium (formerly Propionibacterium) acnes phages.

    PubMed

    Cheng, Lucy; Marinelli, Laura J; Grosset, Noël; Fitz-Gibbon, Sorel T; Bowman, Charles A; Dang, Brian Q; Russell, Daniel A; Jacobs-Sera, Deborah; Shi, Baochen; Pellegrini, Matteo; Miller, Jeff F; Gautier, Michel; Hatfull, Graham F; Modlin, Robert L

    2018-03-01

    A remarkable exception to the large genetic diversity often observed for bacteriophages infecting a specific bacterial host was found for the Cutibacterium acnes (formerly Propionibacterium acnes) phages, which are highly homogeneous. Phages infecting the related species, which is also a member of the Propionibacteriaceae family, Propionibacterium freudenreichii, a bacterium used in production of Swiss-type cheeses, have also been described and are common contaminants of the cheese manufacturing process. However, little is known about their genetic composition and diversity. We obtained seven independently isolated bacteriophages that infect P. freudenreichii from Swiss-type cheese samples, and determined their complete genome sequences. These data revealed that all seven phage isolates are of similar genomic length and GC% content, but their genomes are highly diverse, including genes encoding the capsid, tape measure, and tail proteins. In contrast to C. acnes phages, all P. freudenreichii phage genomes encode a putative integrase protein, suggesting they are capable of lysogenic growth. This is supported by the finding of related prophages in some P. freudenreichii strains. The seven phages could further be distinguished as belonging to two distinct genomic types, or 'clusters', based on nucleotide sequences, and host range analyses conducted on a collection of P. freudenreichii strains show a higher degree of host specificity than is observed for the C. acnes phages. Overall, our data demonstrate P. freudenreichii bacteriophages are distinct from C. acnes phages, as evidenced by their higher genetic diversity, potential for lysogenic growth, and more restricted host ranges. This suggests substantial differences in the evolution of these related species from the Propionibacteriaceae family and their phages, which is potentially related to their distinct environmental niches.

  4. Phage therapy is effective against infection by Mycobacterium ulcerans in a murine footpad model.

    PubMed

    Trigo, Gabriela; Martins, Teresa G; Fraga, Alexandra G; Longatto-Filho, Adhemar; Castro, António G; Azeredo, Joana; Pedrosa, Jorge

    2013-01-01

    Buruli Ulcer (BU) is a neglected, necrotizing skin disease caused by Mycobacterium ulcerans. Currently, there is no vaccine against M. ulcerans infection. Although the World Health Organization recommends a combination of rifampicin and streptomycin for the treatment of BU, clinical management of advanced stages is still based on the surgical resection of infected skin. The use of bacteriophages for the control of bacterial infections has been considered as an alternative or to be used in association with antibiotherapy. Additionally, the mycobacteriophage D29 has previously been shown to display lytic activity against M. ulcerans isolates. We used the mouse footpad model of M. ulcerans infection to evaluate the therapeutic efficacy of treatment with mycobacteriophage D29. Analyses of macroscopic lesions, bacterial burdens, histology and cytokine production were performed in both M. ulcerans-infected footpads and draining lymph nodes (DLN). We have demonstrated that a single subcutaneous injection of the mycobacteriophage D29, administered 33 days after bacterial challenge, was sufficient to decrease pathology and to prevent ulceration. This protection resulted in a significant reduction of M. ulcerans numbers accompanied by an increase of cytokine levels (including IFN-γ), both in footpads and DLN. Additionally, mycobacteriophage D29 treatment induced a cellular infiltrate of a lymphocytic/macrophagic profile. Our observations demonstrate the potential of phage therapy against M. ulcerans infection, paving the way for future studies aiming at the development of novel phage-related therapeutic approaches against BU.

  5. Genomes and Characterization of Phages Bcep22 and BcepIL02, Founders of a Novel Phage Type in Burkholderia cenocepacia▿†

    PubMed Central

    Gill, Jason J.; Summer, Elizabeth J.; Russell, William K.; Cologna, Stephanie M.; Carlile, Thomas M.; Fuller, Alicia C.; Kitsopoulos, Kate; Mebane, Leslie M.; Parkinson, Brandi N.; Sullivan, David; Carmody, Lisa A.; Gonzalez, Carlos F.; LiPuma, John J.; Young, Ry

    2011-01-01

    Within the Burkholderia cepacia complex, B. cenocepacia is the most common species associated with aggressive infections in the lungs of cystic fibrosis patients, causing disease that is often refractive to treatment by antibiotics. Phage therapy may be a potential alternative form of treatment for these infections. Here we describe the genome of the previously described therapeutic B. cenocepacia podophage BcepIL02 and its close relative, Bcep22. Phage Bcep22 was found to contain a circularly permuted genome of 63,882 bp containing 77 genes; BcepIL02 was found to be 62,714 bp and contains 76 predicted genes. Major virion-associated proteins were identified by proteomic analysis. We propose that these phages comprise the founding members of a novel podophage lineage, the Bcep22-like phages. Among the interesting features of these phages are a series of tandemly repeated putative tail fiber genes that are similar to each other and also to one or more such genes in the other phages. Both phages also contain an extremely large (ca. 4,600-amino-acid), virion-associated, multidomain protein that accounts for over 20% of the phages' coding capacity, is widely distributed among other bacterial and phage genomes, and may be involved in facilitating DNA entry in both phage and other mobile DNA elements. The phages, which were previously presumed to be virulent, show evidence of a temperate lifestyle but are apparently unable to form stable lysogens in their hosts. This ambiguity complicates determination of a phage lifestyle, a key consideration in the selection of therapeutic phages. PMID:21804006

  6. Spontaneous Abortion Associated with Zika Virus Infection and Persistent Viremia.

    PubMed

    Goncé, Anna; Martínez, Miguel J; Marbán-Castro, Elena; Saco, Adela; Soler, Anna; Alvarez-Mora, Maria Isabel; Peiro, Aida; Gonzalo, Verónica; Hale, Gillian; Bhatnagar, Julu; López, Marta; Zaki, Sherif; Ordi, Jaume; Bardají, Azucena

    2018-05-01

    We report a case of spontaneous abortion associated with Zika virus infection in a pregnant woman who traveled from Spain to the Dominican Republic and developed a rash. Maternal Zika viremia persisted at least 31 days after onset of symptoms and 21 days after uterine evacuation.

  7. Multiple Abortions and Sexually Transmitted Infections Among Young Migrant Women Working in Entertainment Venues in China.

    PubMed

    Dong, Yanyan; Zhang, Hongbo; Wang, Yongyang; Tao, Haidong; Xu, Song; Xia, Junrui; Huang, Wen; He, Huan; Zaller, Nickolas; Operario, Don

    2015-01-01

    We conducted a survey of 358 young migrant women working in entertainment venues in China to explore the prevalence of and factors associated with two indicators of sexual and reproductive health: (1) multiple abortions and (2) the dual risk of sexually transmitted infections (STI) and abortion history. One quarter (25.4 percent) of the women in this sample had multiple abortions during their lifetime and, of those with any abortion history, 18.3 percent had had an abortion outside of a regulated health clinic. One-third (33.0 percent) of the sample had had an STI during the past year, and approximately one-fourth (23.7 percent) of those women did not receive STI treatment in a public hospital. Approximately one-fourth (23.5 percent) of the sample reported both a history of abortion and an STI during the past year. Women with a history of multiple abortions had significantly lower income levels, were more likely to have sex with clients and with husbands, and tended more to use alcohol before sex. Women who experienced both abortion and STI risks were more likely to report having had unprotected sex, genitourinary tract infections symptoms, anxiety, illicit drug use, and suicidal ideation. Enhanced efforts are needed to improve reproductive and sexual health for female migrants in urban China, particularly those working in entertainment venues.

  8. Strategies for Editing Virulent Staphylococcal Phages Using CRISPR-Cas10.

    PubMed

    Bari, S M Nayeemul; Walker, Forrest C; Cater, Katie; Aslan, Barbaros; Hatoum-Aslan, Asma

    2017-12-15

    Staphylococci are prevalent skin-dwelling bacteria that are also leading causes of antibiotic-resistant infections. Viruses that infect and lyse these organisms (virulent staphylococcal phages) can be used as alternatives to conventional antibiotics and represent promising tools to eliminate or manipulate specific species in the microbiome. However, since over half their genes have unknown functions, virulent staphylococcal phages carry inherent risk to cause unknown downstream side effects. Further, their swift and destructive reproductive cycle make them intractable by current genetic engineering techniques. CRISPR-Cas10 is an elaborate prokaryotic immune system that employs small RNAs and a multisubunit protein complex to detect and destroy phages and other foreign nucleic acids. Some staphylococci naturally possess CRISPR-Cas10 systems, thus providing an attractive tool already installed in the host chromosome to harness for phage genome engineering. However, the efficiency of CRISPR-Cas10 immunity against virulent staphylococcal phages and corresponding utility as a tool to facilitate their genome editing has not been explored. Here, we show that the CRISPR-Cas10 system native to Staphylococcus epidermidis exhibits robust immunity against diverse virulent staphylococcal phages. On the basis of this activity, a general two-step approach was developed to edit these phages that relies upon homologous recombination machinery encoded in the host. Variations of this approach to edit toxic phage genes and access phages that infect CRISPR-less staphylococci are also presented. This versatile set of genetic tools enables the systematic study of phage genes of unknown functions and the design of genetically defined phage-based antimicrobials that can eliminate or manipulate specific Staphylococcus species.

  9. A highly specific phage defense system is a conserved feature of the Vibrio cholerae mobilome

    PubMed Central

    O’Hara, Brendan J.

    2017-01-01

    Vibrio cholerae-specific bacteriophages are common features of the microbial community during cholera infection in humans. Phages impose strong selective pressure that favors the expansion of phage-resistant strains over their vulnerable counterparts. The mechanisms allowing virulent V. cholerae strains to defend against the ubiquitous threat of predatory phages have not been established. Here, we show that V. cholerae PLEs (phage-inducible chromosomal island-like elements) are widespread genomic islands dedicated to phage defense. Analysis of V. cholerae isolates spanning a 60-year collection period identified five unique PLEs. Remarkably, we found that all PLEs (regardless of geographic or temporal origin) respond to infection by a myovirus called ICP1, the most prominent V. cholerae phage found in cholera patient stool samples from Bangladesh. We found that PLE activity reduces phage genome replication and accelerates cell lysis following ICP1 infection, killing infected host cells and preventing the production of progeny phage. PLEs are mobilized by ICP1 infection and can spread to neighboring cells such that protection from phage predation can be horizontally acquired. Our results reveal that PLEs are a persistent feature of the V. cholerae mobilome that are adapted to providing protection from a single predatory phage and advance our understanding of how phages influence pathogen evolution. PMID:28594826

  10. A highly specific phage defense system is a conserved feature of the Vibrio cholerae mobilome.

    PubMed

    O'Hara, Brendan J; Barth, Zachary K; McKitterick, Amelia C; Seed, Kimberley D

    2017-06-01

    Vibrio cholerae-specific bacteriophages are common features of the microbial community during cholera infection in humans. Phages impose strong selective pressure that favors the expansion of phage-resistant strains over their vulnerable counterparts. The mechanisms allowing virulent V. cholerae strains to defend against the ubiquitous threat of predatory phages have not been established. Here, we show that V. cholerae PLEs (phage-inducible chromosomal island-like elements) are widespread genomic islands dedicated to phage defense. Analysis of V. cholerae isolates spanning a 60-year collection period identified five unique PLEs. Remarkably, we found that all PLEs (regardless of geographic or temporal origin) respond to infection by a myovirus called ICP1, the most prominent V. cholerae phage found in cholera patient stool samples from Bangladesh. We found that PLE activity reduces phage genome replication and accelerates cell lysis following ICP1 infection, killing infected host cells and preventing the production of progeny phage. PLEs are mobilized by ICP1 infection and can spread to neighboring cells such that protection from phage predation can be horizontally acquired. Our results reveal that PLEs are a persistent feature of the V. cholerae mobilome that are adapted to providing protection from a single predatory phage and advance our understanding of how phages influence pathogen evolution.

  11. Production of inhalation phage powders using spray freeze drying and spray drying techniques for treatment of respiratory infections

    PubMed Central

    Leung, Sharon S.Y.; Parumasivam, Thaigarajan; Gao, Fiona G.; Carrigy, Nicholas B.; Vehring, Reinhard; Finlay, Warren H.; Morales, Sandra; Britton, Warwick J; Kutter, Elizabeth; Chan, Hak-Kim

    2016-01-01

    Purpose The potential of aerosol phage therapy for treating lung infections has been demonstrated in animal models and clinical studies. This work compared the performance of two dry powder formation techniques, spray freeze drying (SFD) and spray drying (SD), in producing inhalable phage powders. Method A Pseudomonas podoviridae phage, PEV2, was incorporated into multi-component formulation systems consisting of trehalose, mannitol and L-leucine (F1 = 60:20:20 and F2 = 40:40:20). The phage titer loss after the SFD and SD processes and in vitro aerosol performance of the produced powders were assessed. Results A significant titer loss (~ 2 log) was noted for droplet generation using an ultrasonic nozzle employed in the SFD method, but the conventional two-fluid nozzle used in the SD method was less destructive for the phage (~0.75 log loss). The phage were more vulnerable during the evaporative drying process (~0.75 log further loss) compared with the freeze drying step, which caused negligible phage loss. In vitro aerosol performance showed that the SFD powders (~80% phage recovery) provided better phage protection than the SD powders (~20% phage recovery) during the aerosolization process. Despite this, higher total lung doses were obtained for the SD formulations (SD-F1 = 13.1 ± 1.7 × 104 pfu and SD-F2 = 11.0 ± 1.4 × 104 pfu) than from their counterpart SFD formulations (SFD-F1 = 8.3 ± 1.8 × 104 pfu and SFD-F2 = 2.1 ± 0.3 × 104 pfu). Conclusion Overall, the SD method caused less phage reduction during the powder formation process and the resulted powders achieved better aerosol performance for PEV2. PMID:26928668

  12. Filamentous phages of Ralstonia solanacearum: double-edged swords for pathogenic bacteria.

    PubMed

    Yamada, Takashi

    2013-01-01

    Some phages from genus Inovirus use host or bacteriophage-encoded site-specific integrases or recombinases establish a prophage state. During integration or excision, a superinfective form can be produced. The three states (free, prophage, and superinfective) of such phages exert different effects on host bacterial phenotypes. In Ralstonia solanacearum, the causative agent of bacterial wilt disease of crops, the bacterial virulence can be positively or negatively affected by filamentous phages, depending on their state. The presence or absence of a repressor gene in the phage genome may be responsible for the host phenotypic differences (virulent or avirulent) caused by phage infection. This strategy of virulence control may be widespread among filamentous phages that infect pathogenic bacteria of plants.

  13. Metagenomic recovery of phage genomes of uncultured freshwater actinobacteria.

    PubMed

    Ghai, Rohit; Mehrshad, Maliheh; Mizuno, Carolina Megumi; Rodriguez-Valera, Francisco

    2017-01-01

    Low-GC Actinobacteria are among the most abundant and widespread microbes in freshwaters and have largely resisted all cultivation efforts. Consequently, their phages have remained totally unknown. In this work, we have used deep metagenomic sequencing to assemble eight complete genomes of the first tailed phages that infect freshwater Actinobacteria. Their genomes encode the actinobacterial-specific transcription factor whiB, frequently found in mycobacteriophages and also in phages infecting marine pelagic Actinobacteria. Its presence suggests a common and widespread strategy of modulation of host transcriptional machinery upon infection via this transcriptional switch. We present evidence that some whiB-carrying phages infect the acI lineage of Actinobacteria. At least one of them encodes the ADP-ribosylating component of the widespread bacterial AB toxins family (for example, clostridial toxin). We posit that the presence of this toxin reflects a 'trojan horse' strategy, providing protection at the population level to the abundant host microbes against eukaryotic predators.

  14. High stability of Stx2 phage in food and under food-processing conditions.

    PubMed

    Rode, Tone Mari; Axelsson, Lars; Granum, Per Einar; Heir, Even; Holck, Askild; L'abée-Lund, Trine M

    2011-08-01

    Bacteriophages (phages) carrying Shiga toxin genes constitute a major virulence attribute in enterohemorrhagic Escherichia coli (EHEC). Several EHEC outbreaks have been linked to food. The survival of such strains in different foods has received much attention, while the fate of the mobile Shiga toxin-converting phages (Stx phages) has been less studied. We have investigated the stability of an Stx phage in several food products and examined how storage, food processing, and disinfection influence the infectivity of phage particles. The study involved a recombinant Stx phage (Δstx::cat) of an E. coli O103:H25 strain from a Norwegian outbreak in 2006. Temperature, matrix, and time were factors of major importance for the stability of phage particles. Phages stored at cooling temperatures (4°C) showed a dramatic reduction in stability compared to those stored at room temperature. The importance of the matrix was evident at higher temperatures (60°C). Phages in ground beef were below the detection level when heated to 60°C for more than 10 min, while phages in broth exposed to the same heating conditions showed a 5-log-higher stability. The phages tolerated desiccation poorly but were infective for a substantial period of time in solutions. Under moist conditions, they also had a high ability to tolerate exposure to several disinfectants. In a dry-fermented sausage model, phages were shown to infect E. coli in situ. The results show that Stx phage particles can maintain their infectivity in foods and under food-processing conditions.

  15. On The Influence Of Vector Design On Antibody Phage Display

    PubMed Central

    Soltes, Glenn; Hust, Michael; Ng, Kitty K.Y.; Bansal, Aasthaa; Field, Johnathan; Stewart, Donald I.H.; Dübel, Stefan; Cha, Sanghoon; Wiersma, Erik J

    2007-01-01

    Phage display technology is an established technology particularly useful for the generation of monoclonal antibodies (mAbs). The isolation of phagemid-encoded mAb fragments depends on several features of a phage preparation. The aims of this study were to optimize phage display vectors, and to ascertain if different virion features can be optimized independently of each other. Comparisons were made between phagemid virions assembled by g3p-deficient helper phage, Hyperphage, Ex-phage or Phaberge, or corresponding g3p-sufficient helper phage, M13K07. All g3p-deficient helper phage provided a similar level of antibody display, significantly higher than that of M13K07. Hyperphage packaged virions at least 100-fold more efficiently than did Ex-phage or Phaberge. Phaberge's packaging efficiency improved by using a SupE strain. Different phagemids were also compared. Removal of a 56 base pair fragment from the promoter region resulted in increased display level and increased virion production. This critical fragment encodes a lacZ'-like peptide and is also present in other commonly used phagemids. Increasing display level did not show statistical correlation with phage production, phage infectivity or bacterial growth rate. However, phage production was positively correlated to phage infectivity. In summary, this study demonstrates simultaneously optimization of multiple and independent features of importance for phage selection. PMID:16996161

  16. On the influence of vector design on antibody phage display.

    PubMed

    Soltes, Glenn; Hust, Michael; Ng, Kitty K Y; Bansal, Aasthaa; Field, Johnathan; Stewart, Donald I H; Dübel, Stefan; Cha, Sanghoon; Wiersma, Erik J

    2007-01-20

    Phage display technology is an established technology particularly useful for the generation of monoclonal antibodies (mAbs). The isolation of phagemid-encoded mAb fragments depends on several features of a phage preparation. The aims of this study were to optimize phage display vectors, and to ascertain if different virion features can be optimized independently of each other. Comparisons were made between phagemid virions assembled by g3p-deficient helper phage, Hyperphage, Ex-phage or Phaberge, or corresponding g3p-sufficient helper phage, M13K07. All g3p-deficient helper phage provided a similar level of antibody display, significantly higher than that of M13K07. Hyperphage packaged virions at least 100-fold more efficiently than did Ex-phage or Phaberge. Phaberge's packaging efficiency improved by using a SupE strain. Different phagemids were also compared. Removal of a 56 base pair fragment from the promoter region resulted in increased display level and increased virion production. This critical fragment encodes a lacZ'-like peptide and is also present in other commonly used phagemids. Increasing display level did not show statistical correlation with phage production, phage infectivity or bacterial growth rate. However, phage production was positively correlated to phage infectivity. In summary, this study demonstrates simultaneously optimization of multiple and independent features of importance for phage selection.

  17. Comparison of Abortion and Infection after Experimental Challenge of Pregnant Bison and Cattle with Brucella abortus Strain 2308▿

    PubMed Central

    Olsen, S. C.; Johnson, C.

    2011-01-01

    A comparative study was conducted using data from naive bison (n = 45) and cattle (n = 46) from 8 and 6 studies, respectively, in which a standardized Brucella abortus strain 2308 experimental challenge was administered during midgestation. The incidence of abortion, fetal infection, uterine or mammary infection, or infection in maternal tissues after experimental challenge was greater (P < 0.05) in bison than in cattle. In animals that did abort, the time between experimental challenge and abortion was shorter (P < 0.05) for bison than for cattle. Brucella colonization of four target tissues and serologic responses on the standard tube agglutination test at the time of abortion did not differ (P > 0.05) between cattle and bison. The results of our study suggest that naive bison and cattle have similarities and differences after experimental exposure to a virulent B. abortus strain. Although our data suggest that bison may be more susceptible to infection with Brucella, some pathogenic characteristics of brucellosis were similar between bison and cattle. PMID:21976222

  18. Full shut-off of Escherichia coli RNA-polymerase by T7 phage requires a small phage-encoded DNA-binding protein

    PubMed Central

    Tabib-Salazar, Aline; Liu, Bing; Shadrin, Andrey; Burchell, Lynn; Wang, Zhexin; Wang, Zhihao; Goren, Moran G.; Yosef, Ido; Qimron, Udi; Severinov, Konstantin

    2017-01-01

    Abstract Infection of Escherichia coli by the T7 phage leads to rapid and selective inhibition of the bacterial RNA polymerase (RNAP) by the 7 kDa T7 protein Gp2. We describe the identification and functional and structural characterisation of a novel 7 kDa T7 protein, Gp5.7, which adopts a winged helix-turn-helix-like structure and specifically represses transcription initiation from host RNAP-dependent promoters on the phage genome via a mechanism that involves interaction with DNA and the bacterial RNAP. Whereas Gp2 is indispensable for T7 growth in E. coli, we show that Gp5.7 is required for optimal infection outcome. Our findings provide novel insights into how phages fine-tune the activity of the host transcription machinery to ensure both successful and efficient phage progeny development. PMID:28486695

  19. Isolation of Phages for Phage Therapy: A Comparison of Spot Tests and Efficiency of Plating Analyses for Determination of Host Range and Efficacy

    PubMed Central

    Khan Mirzaei, Mohammadali; Nilsson, Anders S.

    2015-01-01

    Phage therapy, treating bacterial infections with bacteriophages, could be a future alternative to antibiotic treatment of bacterial infections. There are, however, several problems to be solved, mainly associated to the biology of phages, the interaction between phages and their bacterial hosts, but also to the vast variation of pathogenic bacteria which implies that large numbers of different phages are going to be needed. All of these phages must under present regulation of medical products undergo extensive clinical testing before they can be applied. It will consequently be of great economic importance that effective and versatile phages are selected and collected into phage libraries, i.e., the selection must be carried out in a way that it results in highly virulent phages with broad host ranges. We have isolated phages using the Escherichia coli reference (ECOR) collection and compared two methods, spot testing and efficiency of plating (EOP), which are frequently used to identify phages suitable for phage therapy. The analyses of the differences between the two methods show that spot tests often overestimate both the overall virulence and the host range and that the results are not correlated to the results of EOP assays. The conclusion is that single dilution spot tests cannot be used for identification and selection of phages to a phage library and should be replaced by EOP assays. The difference between the two methods can be caused by many factors. We have analysed if the differences and lack of correlation could be caused by lysis from without, bacteriocins in the phage lysate, or by the presence of prophages harbouring genes coding for phage resistance systems in the genomes of the bacteria in the ECOR collection. PMID:25761060

  20. Medical Abortion

    MedlinePlus

    ... Headache You may be given medications to manage pain during and after the medical abortion. You may also be given antibiotics, although infection after medical abortion is rare. Your health care provider will explain how much pain and bleeding to expect, depending on the number ...

  1. Romulus and Remus, two phage isolates representing a distinct clade within the Twortlikevirus genus, display suitable properties for phage therapy applications.

    PubMed

    Vandersteegen, Katrien; Kropinski, Andrew M; Nash, John H E; Noben, Jean-Paul; Hermans, Katleen; Lavigne, Rob

    2013-03-01

    The renewed interest in controlling Staphylococcus aureus infections using their natural enemies, bacteriophages, has led to the isolation of a limited number of virulent phages so far. These phages are all members of the Twortlikevirus, displaying little variance. We present two novel closely related (95.9% DNA homology) lytic myoviruses, Romulus and Remus, with double-stranded DNA (dsDNA) genomes of 131,333 bp and 134,643 bp, respectively. Despite their relatedness to Staphylococcus phages K, G1, ISP, and Twort and Listeria phages A511 and P100, Romulus and Remus can be proposed as isolates of a new species within the Twortlikevirus genus. A distinguishing feature for these phage genomes is the unique distribution of group I introns compared to that in other staphylococcal myoviruses. In addition, a hedgehog/intein domain was found within their DNA polymerase genes, and an insertion sequence-encoded transposase exhibits splicing behavior and produces a functional portal protein. From a phage therapy application perspective, Romulus and Remus infected approximately 70% of the tested S. aureus isolates and displayed promising lytic activity against these isolates. Furthermore, both phages showed a rapid initial adsorption and demonstrated biofilm-degrading capacity in a proof-of-concept experiment.

  2. Characterizing Phage Genomes for Therapeutic Applications

    PubMed Central

    Philipson, Casandra W.; Voegtly, Logan J.; Lueder, Matthew R.; Long, Kyle A.; Rice, Gregory K.; Frey, Kenneth G.; Biswas, Biswajit; Cer, Regina Z.; Hamilton, Theron; Bishop-Lilly, Kimberly A.

    2018-01-01

    Multi-drug resistance is increasing at alarming rates. The efficacy of phage therapy, treating bacterial infections with bacteriophages alone or in combination with traditional antibiotics, has been demonstrated in emergency cases in the United States and in other countries, however remains to be approved for wide-spread use in the US. One limiting factor is a lack of guidelines for assessing the genomic safety of phage candidates. We present the phage characterization workflow used by our team to generate data for submitting phages to the Federal Drug Administration (FDA) for authorized use. Essential analysis checkpoints and warnings are detailed for obtaining high-quality genomes, excluding undesirable candidates, rigorously assessing a phage genome for safety and evaluating sequencing contamination. This workflow has been developed in accordance with community standards for high-throughput sequencing of viral genomes as well as principles for ideal phages used for therapy. The feasibility and utility of the pipeline is demonstrated on two new phage genomes that meet all safety criteria. We propose these guidelines as a minimum standard for phages being submitted to the FDA for review as investigational new drug candidates. PMID:29642590

  3. High Stability of Stx2 Phage in Food and under Food-Processing Conditions ▿

    PubMed Central

    Rode, Tone Mari; Axelsson, Lars; Granum, Per Einar; Heir, Even; Holck, Askild; L'Abée-Lund, Trine M.

    2011-01-01

    Bacteriophages (phages) carrying Shiga toxin genes constitute a major virulence attribute in enterohemorrhagic Escherichia coli (EHEC). Several EHEC outbreaks have been linked to food. The survival of such strains in different foods has received much attention, while the fate of the mobile Shiga toxin-converting phages (Stx phages) has been less studied. We have investigated the stability of an Stx phage in several food products and examined how storage, food processing, and disinfection influence the infectivity of phage particles. The study involved a recombinant Stx phage (Δstx::cat) of an E. coli O103:H25 strain from a Norwegian outbreak in 2006. Temperature, matrix, and time were factors of major importance for the stability of phage particles. Phages stored at cooling temperatures (4°C) showed a dramatic reduction in stability compared to those stored at room temperature. The importance of the matrix was evident at higher temperatures (60°C). Phages in ground beef were below the detection level when heated to 60°C for more than 10 min, while phages in broth exposed to the same heating conditions showed a 5-log-higher stability. The phages tolerated desiccation poorly but were infective for a substantial period of time in solutions. Under moist conditions, they also had a high ability to tolerate exposure to several disinfectants. In a dry-fermented sausage model, phages were shown to infect E. coli in situ. The results show that Stx phage particles can maintain their infectivity in foods and under food-processing conditions. PMID:21685156

  4. Production of Inhalation Phage Powders Using Spray Freeze Drying and Spray Drying Techniques for Treatment of Respiratory Infections.

    PubMed

    Leung, Sharon S Y; Parumasivam, Thaigarajan; Gao, Fiona G; Carrigy, Nicholas B; Vehring, Reinhard; Finlay, Warren H; Morales, Sandra; Britton, Warwick J; Kutter, Elizabeth; Chan, Hak-Kim

    2016-06-01

    The potential of aerosol phage therapy for treating lung infections has been demonstrated in animal models and clinical studies. This work compared the performance of two dry powder formation techniques, spray freeze drying (SFD) and spray drying (SD), in producing inhalable phage powders. A Pseudomonas podoviridae phage, PEV2, was incorporated into multi-component formulation systems consisting of trehalose, mannitol and L-leucine (F1 = 60:20:20 and F2 = 40:40:20). The phage titer loss after the SFD and SD processes and in vitro aerosol performance of the produced powders were assessed. A significant titer loss (~2 log) was noted for droplet generation using an ultrasonic nozzle employed in the SFD method, but the conventional two-fluid nozzle used in the SD method was less destructive for the phage (~0.75 log loss). The phage were more vulnerable during the evaporative drying process (~0.75 log further loss) compared with the freeze drying step, which caused negligible phage loss. In vitro aerosol performance showed that the SFD powders (~80% phage recovery) provided better phage protection than the SD powders (~20% phage recovery) during the aerosolization process. Despite this, higher total lung doses were obtained for the SD formulations (SD-F1 = 13.1 ± 1.7 × 10(4) pfu and SD-F2 = 11.0 ± 1.4 × 10(4) pfu) than from their counterpart SFD formulations (SFD-F1 = 8.3 ± 1.8 × 10(4) pfu and SFD-F2 = 2.1 ± 0.3 × 10(4) pfu). Overall, the SD method caused less phage reduction during the powder formation process and the resulted powders achieved better aerosol performance for PEV2.

  5. Twelve previously unknown phage genera are ubiquitous in global oceans

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Holmfeldt, Karin; Solonenko, Natalie; Shah, Manesh B

    Viruses are fundamental to ecosystems ranging from oceans to humans, yet our ability to study them is bottlenecked by the lack of ecologically relevant isolates, resulting in unknowns dominating culture-independent surveys. Here we present genomes from 31 phages infecting multiple strains of the aquatic bacterium Cellulophaga baltica (Bacteroidetes) to provide data for an underrepresented and environmentally abundant bacterial lineage. Comparative genomics delineated 12 phage groups that (i) each represent a new genus, and (ii) represent one novel and four wellknown viral families. This diversity contrasts the few well-studied marine phage systems, but parallels the diversity of phages infecting human-associated bacteria.more » Although all 12 Cellulophaga phages represent new genera, the podoviruses and icosahedral, nontailed ssDNA phages were exceptional, with genomes up to twice as large as those previously observed for each phage type. Structural novelty was also substantial, requiring experimental phage proteomics to identify 83% of the structural proteins. The presence of uncommon nucleotide metabolism genes in four genera likely underscores the importance of scavenging nutrient-rich molecules as previously seen for phages in marine environments. Metagenomic recruitment analyses suggest that these particular Cellulophaga phages are rare and may represent a first glimpse into the phage side of the rare biosphere. However, these analyses also revealed that these phage genera are widespread, occurring in 94% of 137 investigated metagenomes. Together, this diverse and novel collection of phages identifies a small but ubiquitous fraction of unknown marine viral diversity and provides numerous environmentally relevant phage host systems for experimental hypothesis testing.« less

  6. Twelve previously unknown phage genera are ubiquitous in global oceans.

    PubMed

    Holmfeldt, Karin; Solonenko, Natalie; Shah, Manesh; Corrier, Kristen; Riemann, Lasse; Verberkmoes, Nathan C; Sullivan, Matthew B

    2013-07-30

    Viruses are fundamental to ecosystems ranging from oceans to humans, yet our ability to study them is bottlenecked by the lack of ecologically relevant isolates, resulting in "unknowns" dominating culture-independent surveys. Here we present genomes from 31 phages infecting multiple strains of the aquatic bacterium Cellulophaga baltica (Bacteroidetes) to provide data for an underrepresented and environmentally abundant bacterial lineage. Comparative genomics delineated 12 phage groups that (i) each represent a new genus, and (ii) represent one novel and four well-known viral families. This diversity contrasts the few well-studied marine phage systems, but parallels the diversity of phages infecting human-associated bacteria. Although all 12 Cellulophaga phages represent new genera, the podoviruses and icosahedral, nontailed ssDNA phages were exceptional, with genomes up to twice as large as those previously observed for each phage type. Structural novelty was also substantial, requiring experimental phage proteomics to identify 83% of the structural proteins. The presence of uncommon nucleotide metabolism genes in four genera likely underscores the importance of scavenging nutrient-rich molecules as previously seen for phages in marine environments. Metagenomic recruitment analyses suggest that these particular Cellulophaga phages are rare and may represent a first glimpse into the phage side of the rare biosphere. However, these analyses also revealed that these phage genera are widespread, occurring in 94% of 137 investigated metagenomes. Together, this diverse and novel collection of phages identifies a small but ubiquitous fraction of unknown marine viral diversity and provides numerous environmentally relevant phage-host systems for experimental hypothesis testing.

  7. In Vivo Assessment of Phage and Linezolid Based Implant Coatings for Treatment of Methicillin Resistant S. aureus (MRSA) Mediated Orthopaedic Device Related Infections

    PubMed Central

    Kaur, Sandeep; Harjai, Kusum; Chhibber, Sanjay

    2016-01-01

    Staphylococcus comprises up to two-thirds of all pathogens in orthopaedic implant infections with two species respectively Staphylococcus aureus and Staphylococcus epidermidis, being the predominate etiological agents isolated. Further, with the emergence of methicillin-resistant S. aureus (MRSA), treatment of S. aureus implant infections has become more difficult, thus representing a devastating complication. Use of local delivery system consisting of S.aureus specific phage along with linezolid (incorporated in biopolymer) allowing gradual release of the two agents at the implant site represents a new, still unexplored treatment option (against orthopaedic implant infections) that has been studied in an animal model of prosthetic joint infection. Naked wire, hydroxypropyl methylcellulose (HPMC) coated wire and phage and /or linezolid coated K-wire were surgically implanted into the intra-medullary canal of mouse femur bone of respective groups followed by inoculation of S.aureus ATCC 43300(MRSA). Mice implanted with K-wire coated with both the agents i.e phage as well as linezolid (dual coated wires) showed maximum reduction in bacterial adherence, associated inflammation of the joint as well as faster resumption of locomotion and motor function of the limb. Also, all the coating treatments showed no emergence of resistant mutants. Use of dual coated implants incorporating lytic phage (capable of self-multiplication) as well as linezolid presents an attractive and aggressive early approach in preventing as well as treating implant associated infections caused by methicillin resistant S. aureus strains as assessed in a murine model of experimental joint infection. PMID:27333300

  8. A study on some reproductive disorders in dromedary camel herds in Saudi Arabia with special references to uterine infections and abortion.

    PubMed

    Khalafalla, Abdelmalik I; Al Eknah, Marzook M; Abdelaziz, Mahmoud; Ghoneim, Ibrahim M

    2017-06-01

    Dromedary camels complaining from conception failure or abortion were investigated and their herders interviewed in Al Ahsa province, Kingdom of Saudi Arabia (KSA) during 2013 and 2015. The most important reproductive disorder according to the responders is uterine infection (60.2%) followed by obesity (22.3%) then physiological conditions (hormonal disturbances; 7.8%), adhesions (3.9%) and repeat breeders (2.9%). Of the camel herders, 78.6% reported previous occurrence of abortion in their herds and 46% reported abortion cases in the last season (2015/2016), while 21.4% reported no history of abortion. Most of the responders (97.1%) do not call a veterinarian for cases of abortion in their herds and 53.4% do not discard aborted materials. The majority of the herders (76.7%) deny that handling aborted materials or touching vaginal fluids can result in human infection, or replied they do not know. Uterine swab samples were collected and tested by PCR for seven potential pathogens and sera tested for antibodies against bovine viral diarrhea virus (BVDV) and Brucella. Five pathogens were identified in infected uterine samples, namely Coxiella burnetii (36%), Campylobacter spp. (27%), Brucella spp. (17%), Salmonella spp. (13%), and Chlamydia spp. (7%). Sero-prevalence of Brucella and BVDV was 8.2 and 29.1% in overall sera, respectively, and varies with regard to the region. The findings of the present study demonstrate that reproductive disorders dominated by uterine infections and abortions are widespread in dromedary camels in KSA.

  9. Complete genome sequences of three Campylobacter jejuni phage-propagating strains

    USDA-ARS?s Scientific Manuscript database

    Bacteriophage therapy has the potential to reduce Campylobacter jejuni numbers in livestock, but requires a detailed understanding of phage-host interactions. Some C. jejuni strains are readily infected by certain phages, and are thus designated as phage-propagating strains. Here we report the compl...

  10. Differential expression of circulating Th1/ Th2/ Th17 cytokines in serum of Chlamydia trachomatis-infected women undergoing incomplete spontaneous abortion.

    PubMed

    Prasad, Priya; Singh, Namita; Das, Banashree; Raisuddin, Sheikh; Dudeja, Mridu; Rastogi, Sangita

    2017-09-01

    The study aimed to elucidate role of Th1/Th2/Th17 cytokines in the immunopathogenesis of spontaneous abortion in Chlamydia trachomatis (Ct)-positive first-trimester aborters. Endometrial curettage tissue and serum were collected from 145 aborters (spontaneous abortion (SA) group, n = 85; recurrent miscarriage (RM) group, n = 60) and 120 controls attending Department of Obstetrics & Gynecology at Safdarjung hospital, New Delhi (India). Polymerase chain reaction was used to detect Ct plasmid/MOMP, while commercial cytometric bead array kit was utilized to estimate circulating serum cytokines. 13.7% aborters were Ct-positive, however, none was found to be infected among controls. IFN-γ, TNF-α, IL-2, IL-6 and IL-17A cytokines were significantly increased in SA group/RM group (Ct-infected) versus controls. IL-4 showed no difference between groups, while IL-10 was significantly elevated in controls versus Ct-infected subjects in SA group/RM group. Furthermore, IFN-γ, TNF-α, IL-6, IL-17A cytokines were significantly elevated in Ct-positive RM group versus Chlamydia-infected SA group. However, IL-2, IL-4 and IL-10 cytokines showed no significant difference between Ct-positive SA group versus infected RM group. Positive correlation was found between few cytokines (TNF-α and IFN-γ/IL-17A; IL-17A and IFN-γ/IL-6) in Ct-positive aborters. Our study clearly established the role of Th1/Th2/Th17 cytokines in the pathogenesis of spontaneous abortion in Ct-infected subjects and found that Chlamydia-positive recurrent aborters had a predominant Th1/Th17 bias. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Development of a High Throughput Assay for Indirectly Measuring Phage Growth Using the OmniLog (trademark) System

    DTIC Science & Technology

    2012-09-01

    and phage Giraffe exhibits a similar morphology (Fig. 1A). Phage BA39 (Fig. 1E) appears to belong to the Myoviridae family (icosahedral head and...see later) but this assignment is tentative. Monitoring the kinetics of bacterial growth using OmniLogTM system upon infection with Giraffe phage...spores with and without infection by Giraffe phage are shown in Figure 2A and B respectively. The growth of 7702 without phage infection followed a

  12. The Global Reciprocal Reprogramming between Mycobacteriophage SWU1 and Mycobacterium Reveals the Molecular Strategy of Subversion and Promotion of Phage Infection

    PubMed Central

    Fan, Xiangyu; Duan, Xiangke; Tong, Yan; Huang, Qinqin; Zhou, Mingliang; Wang, Huan; Zeng, Lanying; Young, Ry F.; Xie, Jianping

    2016-01-01

    Bacteriophages are the viruses of bacteria, which have contributed extensively to our understanding of life and modern biology. The phage-mediated bacterial growth inhibition represents immense untapped source for novel antimicrobials. Insights into the interaction between mycobacteriophage and Mycobacterium host will inform better utilizing of mycobacteriophage. In this study, RNA sequencing technology (RNA-seq) was used to explore the global response of Mycobacterium smegmatis mc2155 at an early phase of infection with mycobacteriophage SWU1, key host metabolic processes of M. smegmatis mc2155 shut off by SWU1, and the responsible phage proteins. The results of RNA-seq were confirmed by Real-time PCR and functional assay. 1174 genes of M. smegmatis mc2155 (16.9% of the entire encoding capacity) were differentially regulated by phage infection. These genes belong to six functional categories: (i) signal transduction, (ii) cell energetics, (iii) cell wall biosynthesis, (iv) DNA, RNA, and protein biosynthesis, (v) iron uptake, (vi) central metabolism. The transcription patterns of phage SWU1 were also characterized. This study provided the first global glimpse of the reciprocal reprogramming between the mycobacteriophage and Mycobacterium host. PMID:26858712

  13. Characterization, Genome Sequence, and Analysis of Escherichia Phage CICC 80001, a Bacteriophage Infecting an Efficient L-Aspartic Acid Producing Escherichia coli.

    PubMed

    Xu, Youqiang; Ma, Yuyue; Yao, Su; Jiang, Zengyan; Pei, Jiangsen; Cheng, Chi

    2016-03-01

    Escherichia phage CICC 80001 was isolated from the bacteriophage contaminated medium of an Escherichia coli strain HY-05C (CICC 11022S) which could produce L-aspartic acid. The phage had a head diameter of 45-50 nm and a tail of about 10 nm. The one-step growth curve showed a latent period of 10 min and a rise period of about 20 min. The average burst size was about 198 phage particles per infected cell. Tests were conducted on the plaques, multiplicity of infection, and host range. The genome of CICC 80001 was sequenced with a length of 38,810 bp, and annotated. The key proteins leading to host-cell lysis were phylogenetically analyzed. One protein belonged to class II holin, and the other two belonged to the endopeptidase family and N-acetylmuramoyl-L-alanine amidase family, respectively. The genome showed the sequence identity of 82.7% with that of Enterobacteria phage T7, and carried ten unique open reading frames. The bacteriophage resistant E. coli strain designated CICC 11021S was breeding and its L-aspartase activity was 84.4% of that of CICC 11022S.

  14. Phage adsorption to Lactobacillus plantarum: influence of physiological and environmental factors.

    PubMed

    Marcó, M Briggiler; Reinheimer, J A; Quiberoni, A

    2010-04-15

    Bacteriophage infection of lactic acid bacteria (LAB) constitutes one of the major problems in the dairy industry, causing economic losses and a constant risk of low quality and/or unsafe foods. The first step in the phage biology is the adsorption on the host cell surface. In a previous study, a remarkable thermal, chemical and photocatalytic resistance was demonstrated by four phages of Lactobacillus plantarum (ATCC 8014-B1, ATCC 8014-B2, FAGK1 and FAGK2). In the present work, these phages were used to characterize the adsorption process on L. plantarum ATCC 8014. Clearly, the characterization of this process could increase the possibilities of design useful strategies in order to prevent phage infections. The influence of Ca(2+), temperature, pH and physiological cell state on phage adsorption was investigated. Burst sizes of phages ATCC 8014-B1 and ATCC 8014-B2 were 60 and 83 PFU/infective centre, respectively. The four phages exhibited a high infectivity even at pH 4 and pH 11. Calcium or magnesium ions were not indispensable for cell lysis and plaque formation, and more than 99% of phage particles were adsorbed either in the presence or absence of Ca(2+), after 15 min at 37 degrees C. Phage adsorption was only partially affected at 50 degrees C, while reached its maximum between 30 and 42 degrees C. The highest adsorption values (99.9%) were observed from pH 5 to 7, after 30 min at 37 degrees C. Adsorption rates decreased after the thermal inactivation of cells, though, when 20 microg/ml of chloramphenicol was used, adsorption values were similar on treated and untreated cells. All these results showed that the adsorption process was only partially affected by a few conditions: thermally killed host cells, an incubation temperature of 50 degrees C and pH values of 9 and 10. Nevertheless, and unfortunately, those conditions are not commonly applied during fermented food manufacturing, thus restricting highly the application of strategies currently available to

  15. Full shut-off of Escherichia coli RNA-polymerase by T7 phage requires a small phage-encoded DNA-binding protein.

    PubMed

    Tabib-Salazar, Aline; Liu, Bing; Shadrin, Andrey; Burchell, Lynn; Wang, Zhexin; Wang, Zhihao; Goren, Moran G; Yosef, Ido; Qimron, Udi; Severinov, Konstantin; Matthews, Steve J; Wigneshweraraj, Sivaramesh

    2017-07-27

    Infection of Escherichia coli by the T7 phage leads to rapid and selective inhibition of the bacterial RNA polymerase (RNAP) by the 7 kDa T7 protein Gp2. We describe the identification and functional and structural characterisation of a novel 7 kDa T7 protein, Gp5.7, which adopts a winged helix-turn-helix-like structure and specifically represses transcription initiation from host RNAP-dependent promoters on the phage genome via a mechanism that involves interaction with DNA and the bacterial RNAP. Whereas Gp2 is indispensable for T7 growth in E. coli, we show that Gp5.7 is required for optimal infection outcome. Our findings provide novel insights into how phages fine-tune the activity of the host transcription machinery to ensure both successful and efficient phage progeny development. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. Toxoplasma gondii abortion storm in sheep on a Texas farm and isolation of mouse virulent atypical genotype T. gondii from an aborted lamb from a chronically infected ewe

    USDA-ARS?s Scientific Manuscript database

    Sheep are commonly infected with the protozoan parasite, Toxoplasma gondii. Infection may cause early embryonic death and resorption, fetal death and mummification, abortion, stillbirth, and neonatal death. Most sheep acquire T. gondii infection after birth. Recent studies reported that repeat ovine...

  17. The proportional lack of archaeal pathogens: Do viruses/phages hold the key?

    PubMed Central

    Gill, Erin E; Brinkman, Fiona S L

    2011-01-01

    Although Archaea inhabit the human body and possess some characteristics of pathogens, there is a notable lack of pathogenic archaeal species identified to date. We hypothesize that the scarcity of disease-causing Archaea is due, in part, to mutually-exclusive phage and virus populations infecting Bacteria and Archaea, coupled with an association of bacterial virulence factors with phages or mobile elements. The ability of bacterial phages to infect Bacteria and then use them as a vehicle to infect eukaryotes may be difficult for archaeal viruses to evolve independently. Differences in extracellular structures between Bacteria and Archaea would make adsorption of bacterial phage particles onto Archaea (i.e. horizontal transfer of virulence) exceedingly hard. If phage and virus populations are indeed exclusive to their respective host Domains, this has important implications for both the evolution of pathogens and approaches to infectious disease control. PMID:21328413

  18. The Caulobacter crescentus phage phiCbK: genomics of a canonical phage

    PubMed Central

    2012-01-01

    group is proposed as the founding cohort of a new phage type, the phiCbK-like phages. This work will serve as a foundation for future studies on morphogenesis, infection and phage-host interactions in C. crescentus. PMID:23050599

  19. Foot-and-Mouth Disease Virus-Associated Abortion and Vertical Transmission following Acute Infection in Cattle under Natural Conditions

    DOE PAGES

    Ranjan, Rajeev; Biswal, Jitendra K.; Subramaniam, Saravanan; ...

    2016-12-15

    Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease of cloven-hoofed animals, including domestic and wild host species. During recent FMD outbreaks in India, spontaneous abortions were reported amongst FMD-affected and asymptomatic cows. The current study was an opportunistic investigation of these naturally occurring bovine abortions to assess causality of abortion and vertical transmission of FMDV from infected cows to fetuses. For this purpose, fetal tissue samples of eight abortuses (heart, liver, kidney, spleen, palatine tonsil, umbilical cord, soft palate, tongue, lungs, and submandibular lymph node) were collected and screened by various detection methods, including viral genomemore » detection, virus isolation, and immunomicroscopy. Amongst these cases, gross pathological changes were observed in 3 abortuses. Gross pathological findings included blood-tinged peritoneal and pleural effusions and myocarditis. Hearts of infected calves had mild to moderate degeneration and necrosis of the myocardium with moderate infiltration by mixed inflammatory cells. Localization of FMDV antigen was demonstrated in lungs and soft palate by immunomicroscopy. FMDV serotype O viral genome was recovered from 7 of 8 cases. Infectious FMDV serotype O was rescued by chemical transfection of the total RNA extracted from three soft palate samples and was sequenced to confirm 100% identity of the VP1 (capsid) coding region with isolates collected from infected cattle during the acute phase of infection. Based upon these findings, it may be concluded that FMDV-associated abortion occurred among the infected pregnant cows included within this study and FMDV was subsequently transmitted vertically to fetuses. This is the first documentation of FMDV-associated abortions in cattle.« less

  20. Foot-and-Mouth Disease Virus-Associated Abortion and Vertical Transmission following Acute Infection in Cattle under Natural Conditions

    PubMed Central

    Ranjan, Rajeev; Biswal, Jitendra K.; Subramaniam, Saravanan; Singh, Karam Pal; Stenfeldt, Carolina; Rodriguez, Luis L.; Pattnaik, Bramhadev; Arzt, Jonathan

    2016-01-01

    Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease of cloven-hoofed animals, including domestic and wild host species. During recent FMD outbreaks in India, spontaneous abortions were reported amongst FMD-affected and asymptomatic cows. The current study was an opportunistic investigation of these naturally occurring bovine abortions to assess causality of abortion and vertical transmission of FMDV from infected cows to fetuses. For this purpose, fetal tissue samples of eight abortuses (heart, liver, kidney, spleen, palatine tonsil, umbilical cord, soft palate, tongue, lungs, and submandibular lymph node) were collected and screened by various detection methods, including viral genome detection, virus isolation, and immunomicroscopy. Amongst these cases, gross pathological changes were observed in 3 abortuses. Gross pathological findings included blood-tinged peritoneal and pleural effusions and myocarditis. Hearts of infected calves had mild to moderate degeneration and necrosis of the myocardium with moderate infiltration by mixed inflammatory cells. Localization of FMDV antigen was demonstrated in lungs and soft palate by immunomicroscopy. FMDV serotype O viral genome was recovered from 7 of 8 cases. Infectious FMDV serotype O was rescued by chemical transfection of the total RNA extracted from three soft palate samples and was sequenced to confirm 100% identity of the VP1 (capsid) coding region with isolates collected from infected cattle during the acute phase of infection. Based upon these findings, it may be concluded that FMDV-associated abortion occurred among the infected pregnant cows included within this study and FMDV was subsequently transmitted vertically to fetuses. This is the first documentation of FMDV-associated abortions in cattle. PMID:27977708

  1. Foot-and-Mouth Disease Virus-Associated Abortion and Vertical Transmission following Acute Infection in Cattle under Natural Conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ranjan, Rajeev; Biswal, Jitendra K.; Subramaniam, Saravanan

    Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease of cloven-hoofed animals, including domestic and wild host species. During recent FMD outbreaks in India, spontaneous abortions were reported amongst FMD-affected and asymptomatic cows. The current study was an opportunistic investigation of these naturally occurring bovine abortions to assess causality of abortion and vertical transmission of FMDV from infected cows to fetuses. For this purpose, fetal tissue samples of eight abortuses (heart, liver, kidney, spleen, palatine tonsil, umbilical cord, soft palate, tongue, lungs, and submandibular lymph node) were collected and screened by various detection methods, including viral genomemore » detection, virus isolation, and immunomicroscopy. Amongst these cases, gross pathological changes were observed in 3 abortuses. Gross pathological findings included blood-tinged peritoneal and pleural effusions and myocarditis. Hearts of infected calves had mild to moderate degeneration and necrosis of the myocardium with moderate infiltration by mixed inflammatory cells. Localization of FMDV antigen was demonstrated in lungs and soft palate by immunomicroscopy. FMDV serotype O viral genome was recovered from 7 of 8 cases. Infectious FMDV serotype O was rescued by chemical transfection of the total RNA extracted from three soft palate samples and was sequenced to confirm 100% identity of the VP1 (capsid) coding region with isolates collected from infected cattle during the acute phase of infection. Based upon these findings, it may be concluded that FMDV-associated abortion occurred among the infected pregnant cows included within this study and FMDV was subsequently transmitted vertically to fetuses. This is the first documentation of FMDV-associated abortions in cattle.« less

  2. Phage Therapy Approaches to Reducing Pathogen Persistence and Transmission in Animal Production Environments: Opportunities and Challenges.

    PubMed

    Colavecchio, Anna; Goodridge, Lawrence D

    2017-06-01

    The era of genomics has allowed for characterization of phages for use as antimicrobials to treat animal infections with a level of precision never before realized. As more research in phage therapy has been conducted, several advantages of phage therapy have been realized, including the ubiquitous nature, specificity, prevalence in the biosphere, and low inherent toxicity of phages, which makes them a safe and sustainable technology for control of animal diseases. These unique qualities of phages have led to several opportunities with respect to emerging trends in infectious disease treatment. However, the opportunities are tempered by several challenges to the successful implementation of phage therapy, such as the fact that an individual phage can only infect one or a few bacterial strains, meaning that large numbers of different phages will likely be needed to treat infections caused by multiple species of bacteria. In addition, phages are only effective if enough of them can reach the site of bacterial colonization, but clearance by the immune system upon introduction to the animal is a reality that must be overcome. Finally, bacterial resistance to the phages may develop, resulting in treatment failure. Even a successful phage infection and lysis of its host has consequences, because large amounts of endotoxin are released upon lysis of Gram-negative bacteria, which can lead to local and systemic complications. Overcoming these challenges will require careful design and development of phage cocktails, including comprehensive characterization of phage host range and assessment of immunological risks associated with phage treatment.

  3. Phages in the Human Body.

    PubMed

    Navarro, Ferran; Muniesa, Maite

    2017-01-01

    Bacteriophages, viruses that infect bacteria, have re-emerged as powerful regulators of bacterial populations in natural ecosystems. Phages invade the human body, just as they do other natural environments, to such an extent that they are the most numerous group in the human virome. This was only revealed in recent metagenomic studies, despite the fact that the presence of phages in the human body was reported decades ago. The influence of the presence of phages in humans has yet to be evaluated; but as in marine environments, a clear role in the regulation of bacterial populations could be envisaged, that might have an impact on human health. Moreover, phages are excellent vehicles of genetic transfer, and they contribute to the evolution of bacterial cells in the human body by spreading and acquiring DNA horizontally. The abundance of phages in the human body does not pass unnoticed and the immune system reacts to them, although it is not clear to what extent. Finally, the presence of phages in human samples, which most of the time is not considered, can influence and bias microbiological and molecular results; and, in view of the evidences, some studies suggest that more attention needs to be paid to their interference.

  4. Phage lytic enzymes: a history.

    PubMed

    Trudil, David

    2015-02-01

    There are many recent studies regarding the efficacy of bacteriophage-related lytic enzymes: the enzymes of 'bacteria-eaters' or viruses that infect bacteria. By degrading the cell wall of the targeted bacteria, these lytic enzymes have been shown to efficiently lyse Gram-positive bacteria without affecting normal flora and non-related bacteria. Recent studies have suggested approaches for lysing Gram-negative bacteria as well (Briersa Y, et al., 2014). These enzymes include: phage-lysozyme, endolysin, lysozyme, lysin, phage lysin, phage lytic enzymes, phageassociated enzymes, enzybiotics, muralysin, muramidase, virolysin and designations such as Ply, PAE and others. Bacteriophages are viruses that kill bacteria, do not contribute to antimicrobial resistance, are easy to develop, inexpensive to manufacture and safe for humans, animals and the environment. The current focus on lytic enzymes has been on their use as anti-infectives in humans and more recently in agricultural research models. The initial translational application of lytic enzymes, however, was not associated with treating or preventing a specific disease but rather as an extraction method to be incorporated in a rapid bacterial detection assay (Bernstein D, 1997).The current review traces the translational history of phage lytic enzymes-from their initial discovery in 1986 for the rapid detection of group A streptococcus in clinical specimens to evolving applications in the detection and prevention of disease in humans and in agriculture.

  5. Tales of diversity: Genomic and morphological characteristics of forty-six Arthrobacter phages

    PubMed Central

    Adair, Tamarah L.; Afram, Patricia; Allen, Katherine G.; Archambault, Megan L.; Aziz, Rahat M.; Bagnasco, Filippa G.; Ball, Sarah L.; Barrett, Natalie A.; Benjamin, Robert C.; Blasi, Christopher J.; Borst, Katherine; Braun, Mary A.; Broomell, Haley; Brown, Conner B.; Brynell, Zachary S.; Bue, Ashley B.; Burke, Sydney O.; Casazza, William; Cautela, Julia A.; Chen, Kevin; Chimalakonda, Nitish S.; Chudoff, Dylan; Connor, Jade A.; Cross, Trevor S.; Curtis, Kyra N.; Dahlke, Jessica A.; Deaton, Bethany M.; Degroote, Sarah J.; DeNigris, Danielle M.; DeRuff, Katherine C.; Dolan, Milan; Dunbar, David; Egan, Marisa S.; Evans, Daniel R.; Fahnestock, Abby K.; Farooq, Amal; Finn, Garrett; Fratus, Christopher R.; Gaffney, Bobby L.; Garlena, Rebecca A.; Garrigan, Kelly E.; Gibbon, Bryan C.; Goedde, Michael A.; Guerrero Bustamante, Carlos A.; Harrison, Melinda; Hartwell, Megan C.; Heckman, Emily L.; Huang, Jennifer; Hughes, Lee E.; Hyduchak, Kathryn M.; Jacob, Aswathi E.; Kaku, Machika; Karstens, Allen W.; Kenna, Margaret A.; Khetarpal, Susheel; King, Rodney A.; Kobokovich, Amanda L.; Kolev, Hannah; Konde, Sai A.; Kriese, Elizabeth; Lamey, Morgan E.; Lantz, Carter N.; Lapin, Jonathan S.; Lawson, Temiloluwa O.; Lee, In Young; Lee, Scott M.; Lee-Soety, Julia Y.; Lehmann, Emily M.; London, Shawn C.; Lopez, A. Javier; Lynch, Kelly C.; Mageeney, Catherine M.; Martynyuk, Tetyana; Mathew, Kevin J.; Mavrich, Travis N.; McDaniel, Christopher M.; McDonald, Hannah; McManus, C. Joel; Medrano, Jessica E.; Mele, Francis E.; Menninger, Jennifer E.; Miller, Sierra N.; Minick, Josephine E.; Nabua, Courtney T.; Napoli, Caroline K.; Nkangabwa, Martha; Oates, Elizabeth A.; Ott, Cassandra T.; Pellerino, Sarah K.; Pinamont, William J.; Pirnie, Ross T.; Pizzorno, Marie C.; Plautz, Emilee J.; Pope, Welkin H.; Pruett, Katelyn M.; Rickstrew, Gabbi; Rimple, Patrick A.; Rinehart, Claire A.; Robinson, Kayla M.; Rose, Victoria A.; Russell, Daniel A.; Schick, Amelia M.; Schlossman, Julia; Schneider, Victoria M.; Sells, Chloe A.; Sieker, Jeremy W.; Silva, Morgan P.; Silvi, Marissa M.; Simon, Stephanie E.; Staples, Amanda K.; Steed, Isabelle L.; Stowe, Emily L.; Stueven, Noah A.; Swartz, Porter T.; Sweet, Emma A.; Sweetman, Abigail T.; Tender, Corrina; Terry, Katrina; Thomas, Chrystal; Thomas, Daniel S.; Thompson, Allison R.; Vanderveen, Lorianna; Varma, Rohan; Vaught, Hannah L.; Vo, Quynh D.; Vonberg, Zachary T.; Ware, Vassie C.; Warrad, Yasmene M.; Wathen, Kaitlyn E.; Weinstein, Jonathan L.; Wyper, Jacqueline F.; Yankauskas, Jakob R.; Zhang, Christine

    2017-01-01

    The vast bacteriophage population harbors an immense reservoir of genetic information. Almost 2000 phage genomes have been sequenced from phages infecting hosts in the phylum Actinobacteria, and analysis of these genomes reveals substantial diversity, pervasive mosaicism, and novel mechanisms for phage replication and lysogeny. Here, we describe the isolation and genomic characterization of 46 phages from environmental samples at various geographic locations in the U.S. infecting a single Arthrobacter sp. strain. These phages include representatives of all three virion morphologies, and Jasmine is the first sequenced podovirus of an actinobacterial host. The phages also span considerable sequence diversity, and can be grouped into 10 clusters according to their nucleotide diversity, and two singletons each with no close relatives. However, the clusters/singletons appear to be genomically well separated from each other, and relatively few genes are shared between clusters. Genome size varies from among the smallest of siphoviral phages (15,319 bp) to over 70 kbp, and G+C contents range from 45–68%, compared to 63.4% for the host genome. Although temperate phages are common among other actinobacterial hosts, these Arthrobacter phages are primarily lytic, and only the singleton Galaxy is likely temperate. PMID:28715480

  6. Relation between parvovirus B19 infection and fetal mortality and spontaneous abortion.

    PubMed

    Shabani, Zahra; Esghaei, Maryam; Keyvani, Hossein; Shabani, Fateme; Sarmadi, Fateme; Mollaie, Hamidreza; Monavari, Seyed Hamidreza

    2015-01-01

    Infection with parvovirus B19 may cause fetal losses including spontaneous abortion, intrauterine fetal death and non-immune hydrops fetalis. The aim of this study is to determine the frequency of parvovirus B19 in formalin fixed placental tissues in lost fetuses using real-time PCR method. In this cross-sectional study, 100 formalin fixed placental tissues with unknown cause of fetal death were determined using real-time PCR method after DNA extraction. Six out of 100 cases (6%) were positive for parvovirus B19 using real-time PCR. Gestational age of all positive cases was less than 20 weeks with a mean of 12.3 weeks. Three cases have a history of abortion and all of positive cases were collected in spring. Mean age of positive cases were 28 years. Parvovirus B19 during pregnancy can infect red precursor cells and induces apoptosis or lyses these cells that resulting in anemia and congestive heart failure leading to fetal death. Management of parvovirus B19 infection in pregnant women is important because immediate diagnosis and transfusion in hydropsic fetuses can decrease the risk of fetal death.

  7. The Risk of Human Papillomavirus Infection for Spontaneous Abortion, Spontaneous Preterm Birth, and Pregnancy Rate of Assisted Reproductive Technologies: A Systematic Review and Meta-Analysis.

    PubMed

    Xiong, Yi-Quan; Mo, Yun; Luo, Qiao-Ming; Huo, Shu-Ting; He, Wen-Qiao; Chen, Qing

    2018-04-12

    To estimate the impact of human papillomavirus (HPV) infection on spontaneous abortion, spontaneous preterm birth (sPTB), pregnancy rate of females undergoing assisted reproductive technologies (ART), and spontaneous abortion of ART pregnancy. PubMed, Medline, Embase, and the Cochrane Library were searched until December 16, 2016. The OR or relative risk (RR) with its corresponding 95% CI were selected as effect size. Subgroup analysis of HPV genotype infection (high-risk HPV [HR-HPV] or indiscriminate genotype) was performed. Statistical analysis was conducted using STATA 12.0. Eighteen studies were included. Eight studies revealed no significant association between HPV infection and spontaneous abortion (OR 1.40, 95% CI 0.56-3.50). However, subgroup analysis showed indiscriminate genotype HPV infection increased the ratio of spontaneous abortion with OR of 2.24 (95% CI 1.37-3.65), while HR-HPV infection had no significant effect (OR 0.65, 95% CI 0.21-1.98). The results indicated that HR-HPV infection was a risk for sPTB with a pooled OR of 2.84 (95% CI 1.95-4.14). HPV infection was found to be independent of the ART-based clinical pregnancy rate (RR 1.04, 95% CI 0.64-1.70) and spontaneous abortion of ART pregnancy (RR 1.47, 95% CI 0.86-2.50). Indiscriminate HPV genotype infection can increase the risk of spontaneous abortion and HR-HPV infection was a risk factor for sPTB. However, there was not enough evidence to indicate the association between HPV infection and pregnancy rate of ART, and spontaneous abortion of ART pregnancy. Different genotypes of HPV infection may play a discrepant role in adverse pregnancy outcomes. © 2018 S. Karger AG, Basel.

  8. Phage & phosphatase: a novel phage-based probe for rapid, multi-platform detection of bacteria.

    PubMed

    Alcaine, S D; Pacitto, D; Sela, D A; Nugen, S R

    2015-11-21

    Genetic engineering of bacteriophages allows for the development of rapid, highly specific, and easily manufactured probes for the detection of bacterial pathogens. A challenge for novel probes is the ease of their adoption in real world laboratories. We have engineered the bacteriophage T7, which targets Escherichia coli, to carry the alkaline phosphatase gene, phoA. This inclusion results in phoA overexpression following phage infection of E. coli. Alkaline phosphatase is commonly used in a wide range of diagnostics, and thus a signal produced by our phage-based probe could be detected using common laboratory equipment. Our work demonstrates the successful: (i) modification of T7 phage to carry phoA; (ii) overexpression of alkaline phosphatase in E. coli; and (iii) detection of this T7-induced alkaline phosphatase activity using commercially available colorimetric and chemilumiscent methods. Furthermore, we demonstrate the application of our phage-based probe to rapidly detect low levels of bacteria and discern the antibiotic resistance of E. coli isolates. Using our bioengineered phage-based probe we were able to detect 10(3) CFU per mL of E. coli in 6 hours using a chemiluminescent substrate and 10(4) CFU per mL within 7.5 hours using a colorimetric substrate. We also show the application of this phage-based probe for antibiotic resistance testing. We were able to determine whether an E. coli isolate was resistant to ampicillin within 4.5 hours using chemiluminescent substrate and within 6 hours using a colorimetric substrate. This phage-based scheme could be readily adopted in labs without significant capital investments and can be translated to other phage-bacteria pairs for further detection.

  9. A Case-control Study on the Relationship between Mycoplasma genitalium Infection in Women with Normal Pregnancy and Spontaneous Abortion using Polymerase Chain Reaction.

    PubMed

    Ramazanzadeh, Rashid; Khodabandehloo, Mazaher; Farhadifar, Fariba; Rouhi, Samaneh; Ahmadi, Amjad; Menbari, Shaho; Fallahi, Fariba; Mirnejad, Reza

    2016-10-01

    Mycoplasma genitalium infections are suggested as causes of a number of pathological outcomes in pregnant women. The aim of this study was to evaluate the frequency of M. genitalium infections among pregnant women and its association with spontaneous abortion. In this case-control study we included 109 women with spontaneous abortion with a gestational age of 10-20 weeks (patients), and 109 women with normal pregnancy with a gestational age of 20-37 weeks (controls) in Sanandaj, Iran. Using specific primers and extracted DNA from endocervical swabs, a polymerase chain reaction was conducted for the detection of M. genitalium infection in both groups. The frequency of M. genitalium infection in patient and control groups was one (0.91%) and three (2.75%), respectively. In both control and patient groups using Fisher test, no association between mycoplasma infection and spontaneous abortion was seen. M. genitalium may be positive in the genital tract of some pregnant women but was not associated with spontaneous abortion. Further powerful studies with larger sample sizes are needed for the determination of a possible role of M. genitalium in pregnancy outcomes and spontaneous abortion.

  10. The common zoonotic protozoal diseases causing abortion.

    PubMed

    Shaapan, Raafat Mohamed

    2016-12-01

    Toxoplasmosis, neosporosis, sarcosporidiosis (sarcocystosis) and trypanosomiasis are the common zoonotic protozoal diseases causing abortion which caused by single-celled protozoan parasites; Toxoplasma gondii, Neospora caninum , Sarcocystis spp and Trypanosoma evansi, respectively. Toxoplasmosis is generally considered the most important disease that causing abortion of both pregnant women and different female animals throughout the world, about third of human being population had antibodies against T. gondii . The infection can pass via placenta, causing encephalitis, chorio-retinitis, mental retardation and loss of vision in congenitally-infected children and stillbirth or mummification of the aborted fetuses of livestock. Neosporosis is recognized as a major cause of serious abortion in varieties of wild and domestic animals around the world particularly cattle, the disease cause serious economic losses among dairy and beef cattle due to decrease in milk and meat production. While unlike toxoplasmosis, neosporosis is not recognized as a human pathogen and evidence to date shows that neosporosis is only detected by serology in the human population. Sarcosporidiosis also can cause abortion in animals particularly cattle, buffaloes and sheep with acute infection through high dose of infection with sarcocysts. On the other hand, humans have been reported as final and intermediate host for sarcosporidiosis but not represent a serious health problem. Trypanosomiasis by T. evansi cause dangerous infection among domestic animals in tropical and subtropical areas. Several cases of abortion had been recorded in cattle and buffaloes infected with T. evansi while, a single case of human infection was reported in India. Trichomoniasis and babesiosis abortion occurs with non-zoonotic Trichomonas and Babesia species while the zoonotic species had not been incriminated in induction of abortion in both animals and man. The current review article concluded that there is still

  11. Complete Genome Sequences of 44 Arthrobacter Phages

    PubMed Central

    Klyczek, Karen K.; Adair, Tamarah L.; Adams, Sandra D.; Ball, Sarah L.; Benjamin, Robert C.; Bonilla, J. Alfred; Breitenberger, Caroline A.; Daniels, Charles J.; Gaffney, Bobby L.; Harrison, Melinda; Hughes, Lee E.; King, Rodney A.; Krukonis, Gregory P.; Lopez, A. Javier; Monsen-Collar, Kirsten; Pizzorno, Marie C.; Staples, Amanda K.; Stowe, Emily L.; Garlena, Rebecca A.; Russell, Daniel A.

    2018-01-01

    ABSTRACT We report here the complete genome sequences of 44 phages infecting Arthrobacter sp. strain ATCC 21022. These phages have double-stranded DNA genomes with sizes ranging from 15,680 to 70,707 bp and G+C contents from 45.1% to 68.5%. All three tail types (belonging to the families Siphoviridae, Myoviridae, and Podoviridae) are represented. PMID:29437090

  12. Hyperthermostable binding molecules on phage: Assay components for point-of-care diagnostics for active tuberculosis infection.

    PubMed

    Zhao, Ning; Spencer, John; Schmitt, Margaret A; Fisk, John D

    2017-03-15

    Tuberculosis is the leading cause of death from infectious disease worldwide. The low sensitivity, extended processing time, and high expense of current diagnostics are major challenges to the detection and treatment of tuberculosis. Mycobacterium tuberculosis ornithine transcarbamylase (Mtb OTC, Rv1656) has been identified in the urine of patients with active TB infection and is a promising target for point-of-care diagnostics. Specific binding proteins with low nanomolar affinities for Mtb OTC were selected from a phage display library built upon a hyperthermostable Sso7d scaffold. Phage particles displaying Sso7d variants were utilized to generate a sandwich ELISA-based assay for Mtb OTC. The assay response is linear between 2 ng/mL and 125 ng/mL recombinant Mtb OTC and has a limit of detection of 400 pg/mL recombinant Mtb OTC. The assay employing a phage-based detection reagent is comparable to commercially-available antibody-based biosensors. Importantly, the assay maintains functionality at both neutral and basic pH in presence of salt and urea over the range of concentrations typical for human urine. Phage-based diagnostic systems may feature improved physical stability and cost of production relative to traditional antibody-based reagents, without sacrificing specificity and sensitivity. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Shigella Phages Isolated during a Dysentery Outbreak Reveal Uncommon Structures and Broad Species Diversity.

    PubMed

    Doore, Sarah M; Schrad, Jason R; Dean, William F; Dover, John A; Parent, Kristin N

    2018-04-15

    In 2016, Michigan experienced the largest outbreak of shigellosis, a type of bacillary dysentery caused by Shigella spp., since 1988. Following this outbreak, we isolated 16 novel Shigella -infecting bacteriophages (viruses that infect bacteria) from environmental water sources. Most well-known bacteriophages infect the common laboratory species Escherichia coli and Salmonella enterica , and these phages have built the foundation of molecular and bacteriophage biology. Until now, comparatively few bacteriophages were known to infect Shigella spp., which are close relatives of E. coli We present a comprehensive analysis of these phages' host ranges, genomes, and structures, revealing genome sizes and capsid properties that are shared by very few previously described phages. After sequencing, a majority of the Shigella phages were found to have genomes of an uncommon size, shared by only 2% of all reported phage genomes. To investigate the structural implications of this unusual genome size, we used cryo-electron microscopy to resolve their capsid structures. We determined that these bacteriophage capsids have similarly uncommon geometry. Only two other viruses with this capsid structure have been described. Since most well-known bacteriophages infect Escherichia or Salmonella , our understanding of bacteriophages has been limited to a subset of well-described systems. Continuing to isolate phages using nontraditional strains of bacteria can fill gaps that currently exist in bacteriophage biology. In addition, the prevalence of Shigella phages during a shigellosis outbreak may suggest a potential impact of human health epidemics on local microbial communities. IMPORTANCE Shigella spp. bacteria are causative agents of dysentery and affect more than 164 million people worldwide every year. Despite the need to combat antibiotic-resistant Shigella strains, relatively few Shigella -infecting bacteriophages have been described. By specifically looking for Shigella

  14. Learning from Bacteriophages - Advantages and Limitations of Phage and Phage-Encoded Protein Applications

    PubMed Central

    Drulis-Kawa, Zuzanna; Majkowska-Skrobek, Grażyna; Maciejewska, Barbara; Delattre, Anne-Sophie; Lavigne, Rob

    2012-01-01

    The emergence of bacteria resistance to most of the currently available antibiotics has become a critical therapeutic problem. The bacteria causing both hospital and community-acquired infections are most often multidrug resistant. In view of the alarming level of antibiotic resistance between bacterial species and difficulties with treatment, alternative or supportive antibacterial cure has to be developed. The presented review focuses on the major characteristics of bacteriophages and phage-encoded proteins affecting their usefulness as antimicrobial agents. We discuss several issues such as mode of action, pharmacodynamics, pharmacokinetics, resistance and manufacturing aspects of bacteriophages and phage-encoded proteins application. PMID:23305359

  15. Molecular Characterization of Three Lactobacillus delbrueckii subsp. bulgaricus Phages

    PubMed Central

    Casey, Eoghan; Mahony, Jennifer; O'Connell-Motherway, Mary; Bottacini, Francesca; Cornelissen, Anneleen; Neve, Horst; Heller, Knut J.; Noben, Jean-Paul; Dal Bello, Fabio

    2014-01-01

    In this study, three phages infecting Lactobacillus delbrueckii subsp. bulgaricus, named Ld3, Ld17, and Ld25A, were isolated from whey samples obtained from various industrial fermentations. These phages were further characterized in a multifaceted approach: (i) biological and physical characterization through host range analysis and electron microscopy; (ii) genetic assessment through genome analysis; (iii) mass spectrometry analysis of the structural components of the phages; and (iv), for one phage, transcriptional analysis by Northern hybridization, reverse transcription-PCR, and primer extension. The three obtained phage genomes display high levels of sequence identity to each other and to genomes of the so-called group b L. delbrueckii phages c5, LL-Ku, and phiLdb, where some of the observed differences are believed to be responsible for host range variations. PMID:25002431

  16. The genome of the Erwinia amylovora phage PhiEaH1 reveals greater diversity and broadens the applicability of phages for the treatment of fire blight.

    PubMed

    Meczker, Katalin; Dömötör, Dóra; Vass, János; Rákhely, Gábor; Schneider, György; Kovács, Tamás

    2014-01-01

    The enterobacterium Erwinia amylovora is the causal agent of fire blight. This study presents the analysis of the complete genome of phage PhiEaH1, isolated from the soil surrounding an E. amylovora-infected apple tree in Hungary. Its genome is 218 kb in size, containing 244 ORFs. PhiEaH1 is the second E. amylovora infecting phage from the Siphoviridae family whose complete genome sequence was determined. Beside PhiEaH2, PhiEaH1 is the other active component of Erwiphage, the first bacteriophage-based pesticide on the market against E. amylovora. Comparative genome analysis in this study has revealed that PhiEaH1 not only differs from the 10 formerly sequenced E. amylovora bacteriophages belonging to other phage families, but also from PhiEaH2. Sequencing of more Siphoviridae phage genomes might reveal further diversity, providing opportunities for the development of even more effective biological control agents, phage cocktails against Erwinia fire blight disease of commercial fruit crops.

  17. A cocktail of in vitro efficient phages is not a guarantee for in vivo therapeutic results against avian colibacillosis.

    PubMed

    Tsonos, Jessica; Oosterik, Leon H; Tuntufye, Huruma N; Klumpp, Jochen; Butaye, Patrick; De Greve, Henri; Hernalsteens, Jean-Pierre; Lavigne, Rob; Goddeeris, Bruno M

    2014-07-16

    Avian pathogenic Escherichia coli (APEC) causes colibacillosis in poultry, leading to important economic losses worldwide. To cure APEC-infected chickens, a cocktail of four different APEC-specific bacteriophages (phages) was composed and tested. Specific phages were selected from a collection of phages isolated in Belgium. The selection was based on their obligate lytic infection cycle, a broad host range, low cross-resistance and low frequency of development of resistant APEC mutants. Genome analysis of the phages indicated they were close relatives of T4 and N4, considered to be safe in vivo. Chickens were intratracheally infected with APEC strain CH2 (serogroup O78), causing a mortality of about 50% during the seven days following the infection. The phage cocktail was administered 2h after the infection, via three different ways: intratracheally, intra-esophageally or via the drinking water. Treated groups did not show a significant decrease in mortality, lesion scores or weight loss compared to untreated groups, although the APEC-specific phages could be re-isolated from the lung and heart of chickens that were euthanized. Moreover, the re-isolated bacteria from infected chickens had remained sensitive to the phage cocktail. Our results indicate that the efficiency of the phage cocktail used in treating CH2-infected chickens in vivo is negligible, even though in vitro, the phages in the cocktail were able to efficiently lyse the APEC strain CH2. Our results emphasize that the 'traditional' pathway of isolation, followed by phenotypical and genotypical characterization of phages composing the cocktail, does not lead to success in phage therapy in all cases. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. PhiSiGns: an online tool to identify signature genes in phages and design PCR primers for examining phage diversity.

    PubMed

    Dwivedi, Bhakti; Schmieder, Robert; Goldsmith, Dawn B; Edwards, Robert A; Breitbart, Mya

    2012-03-04

    Phages (viruses that infect bacteria) have gained significant attention because of their abundance, diversity and important ecological roles. However, the lack of a universal gene shared by all phages presents a challenge for phage identification and characterization, especially in environmental samples where it is difficult to culture phage-host systems. Homologous conserved genes (or "signature genes") present in groups of closely-related phages can be used to explore phage diversity and define evolutionary relationships amongst these phages. Bioinformatic approaches are needed to identify candidate signature genes and design PCR primers to amplify those genes from environmental samples; however, there is currently no existing computational tool that biologists can use for this purpose. Here we present PhiSiGns, a web-based and standalone application that performs a pairwise comparison of each gene present in user-selected phage genomes, identifies signature genes, generates alignments of these genes, and designs potential PCR primer pairs. PhiSiGns is available at (http://www.phantome.org/phisigns/; http://phisigns.sourceforge.net/) with a link to the source code. Here we describe the specifications of PhiSiGns and demonstrate its application with a case study. PhiSiGns provides phage biologists with a user-friendly tool to identify signature genes and design PCR primers to amplify related genes from uncultured phages in environmental samples. This bioinformatics tool will facilitate the development of novel signature genes for use as molecular markers in studies of phage diversity, phylogeny, and evolution.

  19. Landscape Phage: Evolution from Phage Display to Nanobiotechnology.

    PubMed

    Petrenko, Valery A

    2018-06-07

    The development of phage engineering technology has led to the construction of a novel type of phage display library-a collection of nanofiber materials with diverse molecular landscapes accommodated on the surface of phage particles. These new nanomaterials, called the "landscape phage", serve as a huge resource of diagnostic/detection probes and versatile construction materials for the preparation of phage-functionalized biosensors and phage-targeted nanomedicines. Landscape-phage-derived probes interact with biological threat agents and generate detectable signals as a part of robust and inexpensive molecular recognition interfaces introduced in mobile detection devices. The use of landscape-phage-based interfaces may greatly improve the sensitivity, selectivity, robustness, and longevity of these devices. In another area of bioengineering, landscape-phage technology has facilitated the development and testing of targeted nanomedicines. The development of high-throughput phage selection methods resulted in the discovery of a variety of cancer cell-associated phages and phage proteins demonstrating natural proficiency to self-assemble into various drug- and gene-targeting nanovehicles. The application of this new "phage-programmed-nanomedicines" concept led to the development of a number of cancer cell-targeting nanomedicine platforms, which demonstrated anticancer efficacy in both in vitro and in vivo experiments. This review was prepared to attract the attention of chemical scientists and bioengineers seeking to develop functionalized nanomaterials and use them in different areas of bioscience, medicine, and engineering.

  20. Complete Genome Sequences of 44 Arthrobacter Phages.

    PubMed

    Klyczek, Karen K; Jacobs-Sera, Deborah; Adair, Tamarah L; Adams, Sandra D; Ball, Sarah L; Benjamin, Robert C; Bonilla, J Alfred; Breitenberger, Caroline A; Daniels, Charles J; Gaffney, Bobby L; Harrison, Melinda; Hughes, Lee E; King, Rodney A; Krukonis, Gregory P; Lopez, A Javier; Monsen-Collar, Kirsten; Pizzorno, Marie C; Rinehart, Claire A; Staples, Amanda K; Stowe, Emily L; Garlena, Rebecca A; Russell, Daniel A; Cresawn, Steven G; Pope, Welkin H; Hatfull, Graham F

    2018-02-01

    We report here the complete genome sequences of 44 phages infecting Arthrobacter sp. strain ATCC 21022. These phages have double-stranded DNA genomes with sizes ranging from 15,680 to 70,707 bp and G+C contents from 45.1% to 68.5%. All three tail types (belonging to the families Siphoviridae , Myoviridae , and Podoviridae ) are represented. Copyright © 2018 Klyczek et al.

  1. Ciprofloxacin and Trimethoprim Cause Phage Induction and Virulence Modulation in Staphylococcus aureus

    PubMed Central

    Goerke, Christiane; Köller, Johanna; Wolz, Christiane

    2006-01-01

    In Staphylococcus aureus strains of human origin, phages which integrate into the chromosomal gene coding for β-hemolysin (hlb) are widely distributed. Most of them encode accessory virulence determinants such as staphylokinase (sak) or enterotoxins. Here, we analyzed the effects of ciprofloxacin and trimethoprim on phage induction and expression of phage-encoded virulence factors by using isolates from patients with cystic fibrosis for which the induction of hlb-converting phages was demonstrated in vivo (C. Goerke, S. Matias y Papenberg, S. Dasbach, K. Dietz, R. Ziebach, B. C. Kahl, and C. Wolz, J. Infect. Dis. 189:724-734, 2004) as well as a φ13 lysogen of phage-cured strain 8325-4. Treatment of lysogens with subinhibitory concentrations of either antibiotic resulted in (i) delysogenization of strains resembling the isolates picked up after chronic lung infection and (ii) replication of phages in the bacterial host in a dose-dependent manner. Ciprofloxacin treatment resulted in enhanced recA transcription, indicating involvement of the SOS response in phage mobilization. Induction of φ13 was linked to elevated expression of the phage-encoded virulence gene sak, chiefly due to the activation of latent phage promoters. In summary, we could show the induction of hlb-converting phages and a subsequent virulence modulation of the host bacterium by ciprofloxacin and trimethoprim. PMID:16377683

  2. Characterization of novel Staphylococcus aureus lytic phage and defining their combinatorial virulence using the OmniLog® system

    PubMed Central

    Estrella, Luis A.; Quinones, Javier; Henry, Matthew; Hannah, Ryan M.; Pope, Robert K.; Hamilton, Theron; Teneza-mora, Nimfa; Hall, Eric; Biswajit, Biswas

    2016-01-01

    ABSTRACT Skin and soft tissue infections (SSTI) caused by methicillin resistant Staphylococcus aureus (MRSA) are difficult to treat. Bacteriophage (phage) represent a potential alternate treatment for antibiotic resistant bacterial infections. In this study, 7 novel phage with broad lytic activity for S. aureus were isolated and identified. Screening of a diverse collection of 170 clinical isolates by efficiency of plating (EOP) assays shows that the novel phage are virulent and effectively prevent growth of 70–91% of MRSA and methicillin sensitive S. aureus (MSSA) isolates. Phage K, which was previously identified as having lytic activity on S. aureus was tested on the S. aureus collection and shown to prevent growth of 82% of the isolates. These novel phage group were examined by electron microscopy, the results of which indicate that the phage belong to the Myoviridae family of viruses. The novel phage group requires β-N-acetyl glucosamine (GlcNac) moieties on cell wall teichoic acids for infection. The phage were distinct from, but closely related to, phage K as characterized by restriction endonuclease analysis. Furthermore, growth rate analysis via OmniLog® microplate assay indicates that a combination of phage K, with phage SA0420ᶲ1, SA0456ᶲ1 or SA0482ᶲ1 have a synergistic phage-mediated lytic effect on MRSA and suppress formation of phage resistance. These results indicate that a broad spectrum lytic phage mixture can suppress the emergence of resistant bacterial populations and hence have great potential for combating S. aureus wound infections. PMID:27738555

  3. A new helper phage for improved monovalent display of Fab molecules.

    PubMed

    Beaber, John W; Tam, Eric M; Lao, Llewelyn S; Rondon, Isaac J

    2012-02-28

    Phage display technology is a powerful tool for the identification of novel antibodies for drug discovery. Phage display libraries have been constructed with massive diversity, but their use may be hindered by limited antibody display levels when rescued with the M13KO7 helper phage. Variants of M13KO7 have been constructed previously that increase the levels of display of rescued phage, but all produce phage that display multiple copies of the antibody fragment on their surface and have reduced titer and infectivity. In this study, we describe a new helper phage, XP5, which increased the display level of Fab molecules more than two-fold compared to phage rescued with M13KO7. XP5 uses a combination of ribosome binding site spacing alterations and rare codon clusters to reduce the expression of pIII from the helper phage. This reduction in pIII expression leads to an increase in the incorporation of pIII-Fab fusions during phage rescue. The rescued phage displayed a single copy of the Fab molecule, preventing any avidity effects during the selection process. This also suggests that the percentage of the population of phage displaying a Fab molecule is increased when rescued with XP5. Additionally, the phage titers and infectivity are comparable to libraries rescued with M13KO7. After two rounds of panning we observed a nearly 5-fold increase in the number of antigen binding Fab molecules compared to panning conducted with the same library rescued with M13KO7. The nature of the mutations in XP5 makes it a universal substitute for M13KO7 in pIII-based phage display, compatible with most phagemids and bacterial strains. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Phage Therapy: Various Perspectives on How to Improve the Art.

    PubMed

    Abedon, Stephen T

    2018-01-01

    Use of phages as antibacterial agents has a long and, even, storied history. During that time much has been learned but, to a degree, also forgotten. As a consequence, today we experience a largely preclinical development of a field which already has been subject to substantial clinical practice. This development, as well, is now occurring within a much more rigorously regulated environment than previously had been the case. The consequence is not only a need to reinvent standards of practice but to do so within a more explicitly pharmacological context. Of particular concern is that the application of phages to bacterial infections does not always result in control of the latter, necessitating ongoing thought on how to refine treatment protocols. Here I consider a number of issues relevant to such refinement, focusing on areas which, in my opinion, phage therapy researchers-perhaps especially those new to the field-might struggle with. In order of presentation, I consider how best to describe phage therapy within publications toward achieving a more coherent literature, the importance of Poisson distributions along with killing titers toward understanding phage dosing, the associated importance of establishing sufficient phage numbers in situ to achieve adequate bacteria killing, various problems with the use of multiplicity of infection (MOI) as a description of phage dosing, how to anticipate the basic kinetics of phage-bacteria absorptive interactions, how to distinguish passive from active treatments, and basic approaches toward addressing disappointing efficacy outcomes.

  5. Citrulline-modified phage display: a novel high-throughput discovery approach for the identification of citrulline-containing ligands.

    PubMed

    Somers, Klaartje; Stinissen, Piet; Somers, Veerle

    2011-06-01

    Phage display is a high-throughput technology used to identify ligands for a given target. A drawback of the approach is the absence of PTMs in phage-displayed peptides. The applicability of phage display could be broadened considerably by the implementation of PTMs in this system. The aim of this study was to investigate the possible application of citrullination, a PTM of an arginine into a citrulline amino acid, in filamentous (M13) and lytic (T7) phage display. After in vitro citrullination of T7 and M13 phages, citrullination was confirmed and the infectivity of both citrullinated and non-citrullinated phage was compared by titer determination. We demonstrated the successful in vitro citrullination of T7 and M13 phage-displayed peptides. This in vitro modification did not affect the viability or infectivity of the T7 virions, a necessary prerequisite for the implementation of this approach in T7 phage display. For M13 phage, however, the infecting phage titer decreased five-fold upon citrullination, limiting the use of this modification in M13 phage display. In conclusion, in vitro citrullination can be applied in T7 phage display giving rise to a high-throughput and sensitive approach to identify citrulline-containing ligands by the use of the strengths of phage display technology. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Molecular characterization of three Lactobacillus delbrueckii subsp. bulgaricus phages.

    PubMed

    Casey, Eoghan; Mahony, Jennifer; O'Connell-Motherway, Mary; Bottacini, Francesca; Cornelissen, Anneleen; Neve, Horst; Heller, Knut J; Noben, Jean-Paul; Dal Bello, Fabio; van Sinderen, Douwe

    2014-09-01

    In this study, three phages infecting Lactobacillus delbrueckii subsp. bulgaricus, named Ld3, Ld17, and Ld25A, were isolated from whey samples obtained from various industrial fermentations. These phages were further characterized in a multifaceted approach: (i) biological and physical characterization through host range analysis and electron microscopy; (ii) genetic assessment through genome analysis; (iii) mass spectrometry analysis of the structural components of the phages; and (iv), for one phage, transcriptional analysis by Northern hybridization, reverse transcription-PCR, and primer extension. The three obtained phage genomes display high levels of sequence identity to each other and to genomes of the so-called group b L. delbrueckii phages c5, LL-Ku, and phiLdb, where some of the observed differences are believed to be responsible for host range variations. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  7. Coevolution of CRISPR bacteria and phage in 2 dimensions

    NASA Astrophysics Data System (ADS)

    Han, Pu; Deem, Michael

    2014-03-01

    CRISPR (cluster regularly interspaced short palindromic repeats) is a newly discovered adaptive, heritable immune system of prokaryotes. It can prevent infection of prokaryotes by phage. Most bacteria and almost all archae have CRISPR. The CRISPR system incorporates short nucleotide sequences from viruses. These incorporated sequences provide a historical record of the host and predator coevolution. We simulate the coevolution of bacteria and phage in 2 dimensions. Each phage has multiple proto-spacers that the bacteria can incorporate. Each bacterium can store multiple spacers in its CRISPR. Phages can escape recognition by the CRISPR system via point mutation or recombination. We will discuss the different evolutionary consequences of point mutation or recombination on the coevolution of bacteria and phage. We will also discuss an intriguing ``dynamic phase transition'' in the number of phage as a function of time and mutation rate. We will show that due to the arm race between phages and bacteria, the frequency of spacers and proto-spacers in a population can oscillate quite rapidly.

  8. Hybrid phage displaying SLAQVKYTSASSI induces protection against Candida albicans challenge in BALB/c mice.

    PubMed

    Wang, Yicun; Su, Quanping; Dong, Shuai; Shi, Hongxi; Gao, Xiang; Wang, Li

    2014-01-01

    The polymorphic fungus Candida albicans (C. albicans) can live as an aggressive pathogen and cause many diseases in hosts, for which no effective vaccine exists. The secreted aspartyl proteinase 2 (Sap2) plays a protective role in systemically infected BALB/c mice. Protective cellular immune responses can be preferentially induced when antigens are displayed on small particles. Therefore, the emphasis is placed on developing new phage vaccine to inhibit C. albicans infection. In this study, the ability of the hybrid phage displaying the epitope SLAQVKYTSASSI and recombinant protein of Sap2 (rSap2) for inducing immune protective responses against C. albicans infection was evaluated by lymphoproliferative assay, to gather cytokine and antibody measurements in BALB/c mice. Our results showed that, strong cellular and humoral immune responses were induced in a mouse model immunized with hybrid phage or rSap2. Furthermore, the protection against lethal challenge with C. albicans was observed in mice vaccinated hybrid phage without adjuvant. These findings demonstrate that the hybrid phage displaying the epitope SLAQVKYTSASSI might be a potential vaccine against C. albicans infections.

  9. Phage display of functional αβ single-chain T-cell receptor molecules specific for CD1b:Ac₂SGL complexes from Mycobacterium tuberculosis-infected cells.

    PubMed

    Camacho, Frank; Huggett, Jim; Kim, Louise; Infante, Juan F; Lepore, Marco; Perez, Viviana; Sarmiento, María E; Rook, Graham; Acosta, Armando

    2013-01-01

    The development of molecules specific for M. tuberculosis-infected cells has important implications, as these tools may facilitate understanding of the mechanisms regulating host pathogen interactions in vivo. In addition, development of new tools capable to targeting M. tuberculosis-infected cells may have potential applications to diagnosis, treatment, and prevention of tuberculosis (TB). Due to the lack of CD1b polymorphism, M. tuberculosis lipid-CD1b complexes could be considered as universal tuberculosis infection markers. The aim of the present study was to display on the PIII surface protein of m13 phage, a human αβ single-chain T-cell receptor molecule specific for CD1b:2-stearoyl-3-hydroxyphthioceranoyl-2´-sulfate-α-α´-D-trehalose (Ac₂SGL) which is a complex presented by human cells infected with M. tuberculosis. The results showed the pIII fusion particle was successfully displayed on the phage surface. The study of the recognition of the recombinant phage in ELISA and immunohistochemistry showed the recognition of CD1b:Ac₂SGL complexes and cells in human lung tissue from a tuberculosis patient respectively, suggesting the specific recognition of the lipid-CD1b complex.

  10. Absorption Kinetics of Phage Lambda on Its Host Under Shear Flow

    NASA Astrophysics Data System (ADS)

    Yip, C. W.; Wu, X. L.

    2000-03-01

    Classical blender experiment by Hershey and Chase played a seminal role in illustrating the infectious process of bacteriophage to its host, and showed unequivocally that DNA is responsible for the transmission of heredity. Subsequent works by others have established that interaction between phage particles and bacterial cells is a diffusion-limited process in that, statistically speaking, each collision results in an irreversible infection. However, such a result is hard to reconcile with the fact that the infection appears to be independent of the density of phage receptors on the bacterial cell membrane. Thus, quantitative experiments showing how a phage finds its receptor and how long does it take would be valuable to this paradoxical view. Simple calculations based on Brownian motion of the phage particles show that the interaction time between the receptor and the phage is given by tau=b^2/(5D), where b is the length of the phage and D is its diffusion coefficient. Using a shear flow apparatus we study absorption kinetics of lambda phage on E. Coli (strain YMEL) under different flow conditions, and the results are compared with a simple diffusion model taking into account the hydrodynamic convection and the interaction time tau.

  11. Phage ΦPan70, a Putative Temperate Phage, Controls Pseudomonas aeruginosa in Planktonic, Biofilm and Burn Mouse Model Assays

    PubMed Central

    Holguín, Angela V.; Rangel, Guillermo; Clavijo, Viviana; Prada, Catalina; Mantilla, Marcela; Gomez, María Catalina; Kutter, Elizabeth; Taylor, Corinda; Fineran, Peter C.; Barrios, Andrés Fernando González; Vives, Martha J.

    2015-01-01

    Pseudomonas aeruginosa is one of the Multi-Drug-Resistant organisms most frequently isolated worldwide and, because of a shortage of new antibiotics, bacteriophages are considered an alternative for its treatment. Previously, P. aeruginosa phages were isolated and best candidates were chosen based on their ability to form clear plaques and their host range. This work aimed to characterize one of those phages, ΦPan70, preliminarily identified as a good candidate for phage-therapy. We performed infection curves, biofilm removal assays, transmission-electron-microscopy, pulsed-field-gel-electrophoresis, and studied the in vivo ΦPan70 biological activity in the burned mouse model. ΦPan70 was classified as a member of the Myoviridae family and, in both planktonic cells and biofilms, was responsible for a significant reduction in the bacterial population. The burned mouse model showed an animal survival between 80% and 100%, significantly different from the control animals (0%). However, analysis of the ΦPan70 genome revealed that it was 64% identical to F10, a temperate P. aeruginosa phage. Gene annotation indicated ΦPan70 as a new, but possible temperate phage, therefore not ideal for phage-therapy. Based on this, we recommend genome sequence analysis as an early step to select candidate phages for potential application in phage-therapy, before entering into a more intensive characterization. PMID:26274971

  12. PhiSiGns: an online tool to identify signature genes in phages and design PCR primers for examining phage diversity

    PubMed Central

    2012-01-01

    Background Phages (viruses that infect bacteria) have gained significant attention because of their abundance, diversity and important ecological roles. However, the lack of a universal gene shared by all phages presents a challenge for phage identification and characterization, especially in environmental samples where it is difficult to culture phage-host systems. Homologous conserved genes (or "signature genes") present in groups of closely-related phages can be used to explore phage diversity and define evolutionary relationships amongst these phages. Bioinformatic approaches are needed to identify candidate signature genes and design PCR primers to amplify those genes from environmental samples; however, there is currently no existing computational tool that biologists can use for this purpose. Results Here we present PhiSiGns, a web-based and standalone application that performs a pairwise comparison of each gene present in user-selected phage genomes, identifies signature genes, generates alignments of these genes, and designs potential PCR primer pairs. PhiSiGns is available at (http://www.phantome.org/phisigns/; http://phisigns.sourceforge.net/) with a link to the source code. Here we describe the specifications of PhiSiGns and demonstrate its application with a case study. Conclusions PhiSiGns provides phage biologists with a user-friendly tool to identify signature genes and design PCR primers to amplify related genes from uncultured phages in environmental samples. This bioinformatics tool will facilitate the development of novel signature genes for use as molecular markers in studies of phage diversity, phylogeny, and evolution. PMID:22385976

  13. Analyses of Short-Term Antagonistic Evolution of Pseudomonas aeruginosa Strain PAO1 and Phage KPP22 (Myoviridae Family, PB1-Like Virus Genus).

    PubMed

    Uchiyama, Jumpei; Suzuki, Masato; Nishifuji, Koji; Kato, Shin-Ichiro; Miyata, Reina; Nasukawa, Tadahiro; Yamaguchi, Kotoe; Takemura-Uchiyama, Iyo; Ujihara, Takako; Shimakura, Hidekatsu; Murakami, Hironobu; Okamoto, Noriaki; Sakaguchi, Yoshihiko; Shibayama, Keigo; Sakaguchi, Masahiro; Matsuzaki, Shigenobu

    2016-08-01

    Pseudomonas aeruginosa causes serious intractable infections in humans and animals. Bacteriophage (phage) therapy has been applied to treat P. aeruginosa infections, and phages belonging to the PB1-like virus genus in the Myoviridae family have been used as therapeutic phages. To achieve safer and more effective phage therapy, the use of preadapted phages is proposed. To understand in detail such phage preadaptation, the short-term antagonistic evolution of bacteria and phages should be studied. In this study, the short-term antagonistic evolution of bacteria and PB1-like phage was examined by studying phage-resistant clones of P. aeruginosa strain PAO1 and mutant PB1-like phages that had recovered their infectivity. First, phage KPP22 was isolated and characterized; it was classified as belonging to the PB1-like virus genus in the Myoviridae family. Subsequently, three KPP22-resistant PAO1 clones and three KPP22 mutant phages capable of infecting these clones were isolated in three sets of in vitro experiments. It was shown that the bacterial resistance to phage KPP22 was caused by significant decreases in phage adsorption and that the improved infectivity of KPP22 mutant phages was caused by significant increases in phage adsorption. The KPP22-resistant PAO1 clones and the KPP22 mutant phages were then analyzed genetically. All three KPP22-resistant PAO1 clones, which were deficient for the O5 antigen, had a common nonsense mutation in the wzy gene. All the KPP22 mutant phage genomes showed the same four missense mutations in the open reading frames orf060, orf065, and orf086 The information obtained in this study should be useful for further development of safe and efficient phage therapy. Pseudomonas aeruginosa causes serious intractable infections in humans and animals; bacteriophage (phage) therapy has been utilized to treat P. aeruginosa infections, and phages that belong to the PB1-like virus genus in the family Myoviridae have been used as therapeutic

  14. A novel roseobacter phage possesses features of podoviruses, siphoviruses, prophages and gene transfer agents

    PubMed Central

    Zhan, Yuanchao; Huang, Sijun; Voget, Sonja; Simon, Meinhard; Chen, Feng

    2016-01-01

    Bacteria in the Roseobacter lineage have been studied extensively due to their significant biogeochemical roles in the marine ecosystem. However, our knowledge on bacteriophage which infects the Roseobacter clade is still very limited. Here, we report a new bacteriophage, phage DSS3Φ8, which infects marine roseobacter Ruegeria pomeroyi DSS-3. DSS3Φ8 is a lytic siphovirus. Genomic analysis showed that DSS3Φ8 is most closely related to a group of siphoviruses, CbK-like phages, which infect freshwater bacterium Caulobacter crescentus. DSS3Φ8 contains a smaller capsid and has a reduced genome size (146 kb) compared to the CbK-like phages (205–279 kb). DSS3Φ8 contains the DNA polymerase gene which is closely related to T7-like podoviruses. DSS3Φ8 also contains the integrase and repressor genes, indicating its potential to involve in lysogenic cycle. In addition, four GTA (gene transfer agent) genes were identified in the DSS3Φ8 genome. Genomic analysis suggests that DSS3Φ8 is a highly mosaic phage that inherits the genetic features from siphoviruses, podoviruses, prophages and GTAs. This is the first report of CbK-like phages infecting marine bacteria. We believe phage isolation is still a powerful tool that can lead to discovery of new phages and help interpret the overwhelming unknown sequences in the viral metagenomics. PMID:27460944

  15. A novel roseobacter phage possesses features of podoviruses, siphoviruses, prophages and gene transfer agents

    NASA Astrophysics Data System (ADS)

    Zhan, Yuanchao; Huang, Sijun; Voget, Sonja; Simon, Meinhard; Chen, Feng

    2016-07-01

    Bacteria in the Roseobacter lineage have been studied extensively due to their significant biogeochemical roles in the marine ecosystem. However, our knowledge on bacteriophage which infects the Roseobacter clade is still very limited. Here, we report a new bacteriophage, phage DSS3Φ8, which infects marine roseobacter Ruegeria pomeroyi DSS-3. DSS3Φ8 is a lytic siphovirus. Genomic analysis showed that DSS3Φ8 is most closely related to a group of siphoviruses, CbK-like phages, which infect freshwater bacterium Caulobacter crescentus. DSS3Φ8 contains a smaller capsid and has a reduced genome size (146 kb) compared to the CbK-like phages (205-279 kb). DSS3Φ8 contains the DNA polymerase gene which is closely related to T7-like podoviruses. DSS3Φ8 also contains the integrase and repressor genes, indicating its potential to involve in lysogenic cycle. In addition, four GTA (gene transfer agent) genes were identified in the DSS3Φ8 genome. Genomic analysis suggests that DSS3Φ8 is a highly mosaic phage that inherits the genetic features from siphoviruses, podoviruses, prophages and GTAs. This is the first report of CbK-like phages infecting marine bacteria. We believe phage isolation is still a powerful tool that can lead to discovery of new phages and help interpret the overwhelming unknown sequences in the viral metagenomics.

  16. Spatial-temporal epidemiology of human Salmonella Enteritidis infections with major phage types (PTs 1, 4, 5b, 8, 13, and 13a) in Ontario, Canada, 2008-2009.

    PubMed

    Varga, Csaba; Pearl, David L; McEwen, Scott A; Sargeant, Jan M; Pollari, Frank; Guerin, Michele T

    2015-12-17

    In Ontario and Canada, the incidence of human Salmonella enterica serotype Enteritidis (S. Enteritidis) infections have increased steadily during the last decade. Our study evaluated the spatial and temporal epidemiology of the major phage types (PTs) of S. Enteritidis infections to aid public health practitioners design effective prevention and control programs. Data on S. Enteritidis infections between January 1, 2008 and December 31, 2009 were obtained from Ontario's disease surveillance system. Salmonella Enteritidis infections with major phage types were classified by their annual health region-level incidence rates (IRs), monthly IRs, clinical symptoms, and exposure settings. A scan statistic was employed to detect retrospective phage type-specific spatial, temporal, and space-time clusters of S. Enteritidis infections. Space-time cluster cases' exposure settings were evaluated to identify common exposures. 1,336 cases were available for analysis. The six most frequently reported S. Enteritidis PTs were 8 (n = 398), 13a (n = 218), 13 (n = 198), 1 (n = 132), 5b (n = 83), and 4 (n = 76). Reported rates of S. Enteritidis infections with major phage types varied by health region and month. International travel and unknown exposure settings were the most frequently reported settings for PT 5b, 4, and 1 cases, whereas unknown exposure setting, private home, food premise, and international travel were the most frequently reported settings for PT 8, 13, and 13a cases. Diarrhea, abdominal pain, and fever were the most commonly reported clinical symptoms. A number of phage type-specific spatial, temporal, and space-time clusters were identified. Space-time clusters of PTs 1, 4, and 5b occurred mainly during the winter and spring months in the North West, North East, Eastern, Central East, and Central West regions. Space-time clusters of PTs 13 and 13a occurred at different times of the year in the Toronto region. Space-time clusters of PT 8

  17. Yersinia enterocolitica-Specific Infection by Bacteriophages TG1 and ϕR1-RT Is Dependent on Temperature-Regulated Expression of the Phage Host Receptor OmpF.

    PubMed

    Leon-Velarde, Carlos G; Happonen, Lotta; Pajunen, Maria; Leskinen, Katarzyna; Kropinski, Andrew M; Mattinen, Laura; Rajtor, Monika; Zur, Joanna; Smith, Darren; Chen, Shu; Nawaz, Ayesha; Johnson, Roger P; Odumeru, Joseph A; Griffiths, Mansel W; Skurnik, Mikael

    2016-09-01

    Bacteriophages present huge potential both as a resource for developing novel tools for bacterial diagnostics and for use in phage therapy. This potential is also valid for bacteriophages specific for Yersinia enterocolitica To increase our knowledge of Y. enterocolitica-specific phages, we characterized two novel yersiniophages. The genomes of the bacteriophages vB_YenM_TG1 (TG1) and vB_YenM_ϕR1-RT (ϕR1-RT), isolated from pig manure in Canada and from sewage in Finland, consist of linear double-stranded DNA of 162,101 and 168,809 bp, respectively. Their genomes comprise 262 putative coding sequences and 4 tRNA genes and share 91% overall nucleotide identity. Based on phylogenetic analyses of their whole-genome sequences and large terminase subunit protein sequences, a genus named Tg1virus within the family Myoviridae is proposed, with TG1 and ϕR1-RT (R1RT in the ICTV database) as member species. These bacteriophages exhibit a host range restricted to Y. enterocolitica and display lytic activity against the epidemiologically significant serotypes O:3, O:5,27, and O:9 at and below 25°C. Adsorption analyses of lipopolysaccharide (LPS) and OmpF mutants demonstrate that these phages use both the LPS inner core heptosyl residues and the outer membrane protein OmpF as phage receptors. Based on RNA sequencing and quantitative proteomics, we also demonstrate that temperature-dependent infection is due to strong repression of OmpF at 37°C. In addition, ϕR1-RT was shown to be able to enter into a pseudolysogenic state. Together, this work provides further insight into phage-host cell interactions by highlighting the importance of understanding underlying factors which may affect the abundance of phage host receptors on the cell surface. Only a small number of bacteriophages infecting Y. enterocolitica, the predominant causative agent of yersiniosis, have been previously described. Here, two newly isolated Y. enterocolitica phages were studied in detail, with the aim of

  18. Yersinia enterocolitica-Specific Infection by Bacteriophages TG1 and ϕR1-RT Is Dependent on Temperature-Regulated Expression of the Phage Host Receptor OmpF

    PubMed Central

    Happonen, Lotta; Pajunen, Maria; Leskinen, Katarzyna; Kropinski, Andrew M.; Mattinen, Laura; Rajtor, Monika; Zur, Joanna; Smith, Darren; Chen, Shu; Nawaz, Ayesha; Johnson, Roger P.; Odumeru, Joseph A.; Griffiths, Mansel W.

    2016-01-01

    ABSTRACT Bacteriophages present huge potential both as a resource for developing novel tools for bacterial diagnostics and for use in phage therapy. This potential is also valid for bacteriophages specific for Yersinia enterocolitica. To increase our knowledge of Y. enterocolitica-specific phages, we characterized two novel yersiniophages. The genomes of the bacteriophages vB_YenM_TG1 (TG1) and vB_YenM_ϕR1-RT (ϕR1-RT), isolated from pig manure in Canada and from sewage in Finland, consist of linear double-stranded DNA of 162,101 and 168,809 bp, respectively. Their genomes comprise 262 putative coding sequences and 4 tRNA genes and share 91% overall nucleotide identity. Based on phylogenetic analyses of their whole-genome sequences and large terminase subunit protein sequences, a genus named Tg1virus within the family Myoviridae is proposed, with TG1 and ϕR1-RT (R1RT in the ICTV database) as member species. These bacteriophages exhibit a host range restricted to Y. enterocolitica and display lytic activity against the epidemiologically significant serotypes O:3, O:5,27, and O:9 at and below 25°C. Adsorption analyses of lipopolysaccharide (LPS) and OmpF mutants demonstrate that these phages use both the LPS inner core heptosyl residues and the outer membrane protein OmpF as phage receptors. Based on RNA sequencing and quantitative proteomics, we also demonstrate that temperature-dependent infection is due to strong repression of OmpF at 37°C. In addition, ϕR1-RT was shown to be able to enter into a pseudolysogenic state. Together, this work provides further insight into phage-host cell interactions by highlighting the importance of understanding underlying factors which may affect the abundance of phage host receptors on the cell surface. IMPORTANCE Only a small number of bacteriophages infecting Y. enterocolitica, the predominant causative agent of yersiniosis, have been previously described. Here, two newly isolated Y. enterocolitica phages were studied in

  19. Epifluorescence and atomic force microscopy: Two innovative applications for studying phage-host interactions in Lactobacillus helveticus.

    PubMed

    Zago, Miriam; Scaltriti, Erika; Fornasari, Maria Emanuela; Rivetti, Claudio; Grolli, Stefano; Giraffa, Giorgio; Ramoni, Roberto; Carminati, Domenico

    2012-01-01

    Bacteriophages attacking lactic acid bacteria (LAB) still represent a crucial problem in industrial dairy fermentations. The consequences of a phage infection against LAB can lead to fermentation delay, alteration of the product quality and, in most severe cases, the product loss. Phage particles enumeration and phage-host interactions are normally evaluated by conventional plaque count assays, but, in many cases, these methods can be unsuccessful. Bacteriophages of Lactobacillus helveticus, a LAB species widely used as dairy starter or probiotic cultures, are often unable to form lysis plaques, thus impairing their enumeration by plate assay. In this study, we used epifluorescence microscopy to enumerate L. helveticus phage particles from phage-infected cultures and Atomic Force Microscopy (AFM) to visualize both phages and bacteria during the different stages of the lytic cycle. Preliminary, we tested the sensitivity of phage counting by epifluorescence microscopy. To this end, phage particles of ΦAQ113, a lytic phage of L. helveticus isolated from a whey starter culture, were stained by SYBR Green I and enumerated by epifluorescence microscopy. Values obtained by the microscopic method were 10 times higher than plate counts, with a lowest sensitivity limit of ≥6log phage/ml. The interaction of phage ΦAQ113 with its host cell L. helveticus Lh1405 was imaged by AFM after 0, 2 and 5h from phage-host adsorption. The lytic cycle was followed by epifluorescence microscopy counting and the concomitant cell wall changes were visualized by AFM imaging. Our results showed that these two methods can be combined for a reliable phage enumeration and for studying phage and host morphology during infection processes, thus giving a complete overview of phage-host interactions in L. helveticus strains involved in dairy productions. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Phage display creates innovative applications to combat hepatitis B virus

    PubMed Central

    Tan, Wen Siang; Ho, Kok Lian

    2014-01-01

    Hepatitis B virus (HBV) has killed countless lives in human history. The invention of HBV vaccines in the 20th century has reduced significantly the rate of the viral infection. However, currently there is no effective treatment for chronic HBV carriers. Newly emerging vaccine escape mutants and drug resistant strains have complicated the viral eradication program. The entire world is now facing a new threat of HBV and human immunodeficiency virus co-infection. Could phage display provide solutions to these life-threatening problems? This article reviews critically and comprehensively the innovative and potential applications of phage display in the development of vaccines, therapeutic agents, diagnostic reagents, as well as gene and drug delivery systems to combat HBV. The application of phage display in epitope mapping of HBV antigens is also discussed in detail. Although this review mainly focuses on HBV, the innovative applications of phage display could also be extended to other infectious diseases. PMID:25206271

  1. Key Role of Capsular Polysaccharide in the Induction of Systemic Infection and Abortion by Hypervirulent Campylobacter jejuni

    PubMed Central

    Sahin, Orhan; Terhorst, Samantha A.; Burrough, Eric R.; Shen, Zhangqi; Wu, Zuowei; Dai, Lei; Tang, Yizhi; Plummer, Paul J.; Ji, Ju; Yaeger, Michael J.

    2017-01-01

    ABSTRACT Campylobacter jejuni is a zoonotic pathogen, and a hypervirulent clone, named clone SA, has recently emerged as the predominant cause of ovine abortion in the United States. To induce abortion, orally ingested Campylobacter must translocate across the intestinal epithelium, spread systemically in the circulation, and reach the fetoplacental tissue. Bacterial factors involved in these steps are not well understood. C. jejuni is known to produce capsular polysaccharide (CPS), but the specific role that CPS plays in systemic infection and particularly abortion in animals remains to be determined. In this study, we evaluated the role of CPS in bacteremia using a mouse model and in abortion using a pregnant guinea pig model following oral challenge. Compared with C. jejuni NCTC 11168 and 81-176, a clone SA isolate (IA3902) resulted in significantly higher bacterial counts and a significantly longer duration of bacteremia in mice. The loss of capsule production via gene-specific mutagenesis in IA3902 led to the complete abolishment of bacteremia in mice and abortion in pregnant guinea pigs, while complementation of capsule expression almost fully restored these phenotypes. The capsule mutant strain was also impaired for survival in guinea pig sera and sheep blood. Sequence-based analyses revealed that clone SA possesses a unique CPS locus with a mosaic structure, which has been stably maintained in all clone SA isolates derived from various hosts and times. These findings establish CPS as a key virulence factor for the induction of systemic infection and abortion in pregnant animals and provide a viable candidate for the development of vaccines against hypervirulent C. jejuni. PMID:28373351

  2. Basic Phage Mathematics.

    PubMed

    Abedon, Stephen T; Katsaounis, Tena I

    2018-01-01

    Basic mathematical descriptions are useful in phage ecology, applied phage ecology such as in the course of phage therapy, and also toward keeping track of expected phage-bacterial interactions as seen during laboratory manipulation of phages. The most basic mathematical descriptor of phages is their titer, that is, their concentration within stocks, experimental vessels, or other environments. Various phenomena can serve to modify phage titers, and indeed phage titers can vary as a function of how they are measured. An important aspect of how changes in titers can occur results from phage interactions with bacteria. These changes tend to vary in degree as a function of bacterial densities within environments, and particularly densities of those bacteria that are susceptible to or at least adsorbable by a given phage type. Using simple mathematical models one can describe phage-bacterial interactions that give rise particularly to phage adsorption events. With elaboration one can consider changes in both phage and bacterial densities as a function of both time and these interactions. In addition, phages along with their impact on bacteria can be considered as spatially constrained processes. In this chapter we consider the simpler of these concepts, providing in particular detailed verbal explanations toward facile mathematical insight. The primary goal is to stimulate a more informed use and manipulation of phages and phage populations within the laboratory as well as toward more effective phage application outside of the laboratory, such as during phage therapy. More generally, numerous issues and approaches to the quantification of phages are considered along with the quantification of individual, ecological, and applied properties of phages.

  3. Phage display peptide libraries: deviations from randomness and correctives

    PubMed Central

    Ryvkin, Arie; Ashkenazy, Haim; Weiss-Ottolenghi, Yael; Piller, Chen; Pupko, Tal; Gershoni, Jonathan M

    2018-01-01

    Abstract Peptide-expressing phage display libraries are widely used for the interrogation of antibodies. Affinity selected peptides are then analyzed to discover epitope mimetics, or are subjected to computational algorithms for epitope prediction. A critical assumption for these applications is the random representation of amino acids in the initial naïve peptide library. In a previous study, we implemented next generation sequencing to evaluate a naïve library and discovered severe deviations from randomness in UAG codon over-representation as well as in high G phosphoramidite abundance causing amino acid distribution biases. In this study, we demonstrate that the UAG over-representation can be attributed to the burden imposed on the phage upon the assembly of the recombinant Protein 8 subunits. This was corrected by constructing the libraries using supE44-containing bacteria which suppress the UAG driven abortive termination. We also demonstrate that the overabundance of G stems from variant synthesis-efficiency and can be corrected using compensating oligonucleotide-mixtures calibrated by mass spectroscopy. Construction of libraries implementing these correctives results in markedly improved libraries that display random distribution of amino acids, thus ensuring that enriched peptides obtained in biopanning represent a genuine selection event, a fundamental assumption for phage display applications. PMID:29420788

  4. First genome sequences of Achromobacter phages reveal new members of the N4 family.

    PubMed

    Wittmann, Johannes; Dreiseikelmann, Brigitte; Rohde, Manfred; Meier-Kolthoff, Jan P; Bunk, Boyke; Rohde, Christine

    2014-01-27

    Multi-resistant Achromobacter xylosoxidans has been recognized as an emerging pathogen causing nosocomially acquired infections during the last years. Phages as natural opponents could be an alternative to fight such infections. Bacteriophages against this opportunistic pathogen were isolated in a recent study. This study shows a molecular analysis of two podoviruses and reveals first insights into the genomic structure of Achromobacter phages so far. Growth curve experiments and adsorption kinetics were performed for both phages. Adsorption and propagation in cells were visualized by electron microscopy. Both phage genomes were sequenced with the PacBio RS II system based on single molecule, real-time (SMRT) technology and annotated with several bioinformatic tools. To further elucidate the evolutionary relationships between the phage genomes, a phylogenomic analysis was conducted using the genome Blast Distance Phylogeny approach (GBDP). In this study, we present the first detailed analysis of genome sequences of two Achromobacter phages so far. Phages JWAlpha and JWDelta were isolated from two different waste water treatment plants in Germany. Both phages belong to the Podoviridae and contain linear, double-stranded DNA with a length of 72329 bp and 73659 bp, respectively. 92 and 89 putative open reading frames were identified for JWAlpha and JWDelta, respectively, by bioinformatic analysis with several tools. The genomes have nearly the same organization and could be divided into different clusters for transcription, replication, host interaction, head and tail structure and lysis. Detailed annotation via protein comparisons with BLASTP revealed strong similarities to N4-like phages. Analysis of the genomes of Achromobacter phages JWAlpha and JWDelta and comparisons of different gene clusters with other phages revealed that they might be strongly related to other N4-like phages, especially of the Escherichia group. Although all these phages show a highly

  5. Understanding the enormous diversity of bacteriophages: the tailed phages that infect the bacterial family Enterobacteriaceae.

    PubMed

    Grose, Julianne H; Casjens, Sherwood R

    2014-11-01

    Bacteriophages are the predominant biological entity on the planet. The recent explosion of sequence information has made estimates of their diversity possible. We describe the genomic comparison of 337 fully sequenced tailed phages isolated on 18 genera and 31 species of bacteria in the Enterobacteriaceae. These phages were largely unambiguously grouped into 56 diverse clusters (32 lytic and 24 temperate) that have syntenic similarity over >50% of the genomes within each cluster, but substantially less sequence similarity between clusters. Most clusters naturally break into sets of more closely related subclusters, 78% of which are correlated with their host genera. The largest groups of related phages are superclusters united by genome synteny to lambda (81 phages) and T7 (51 phages). This study forms a robust framework for understanding diversity and evolutionary relationships of existing tailed phages, for relating newly discovered phages and for determining host/phage relationships.

  6. Understanding the enormous diversity of bacteriophages: the tailed phages that infect the bacterial family Enterobacteriaceae

    PubMed Central

    Grose, Julianne H.; Casjens, Sherwood R.

    2014-01-01

    Bacteriophages are the predominant biological entity on the planet. The recent explosion of sequence information has made estimates of their diversity possible. We describe the genomic comparison of 337 fully sequenced tailed phages isolated on 18 genera and 31 species of bacteria in the Enterobacteriaceae. These phages were largely unambiguously grouped into 56 diverse clusters (32 lytic and 24 temperate) that have syntenic similarity over >50% of the genomes within each cluster, but substantially less sequence similarity between clusters. Most clusters naturally break into sets of more closely related subclusters, 78% of which are correlated with their host genera. The largest groups of related phages are superclusters united by genome synteny to lambda (81 phages) and T7 (51 phages). This study forms a robust framework for understanding diversity and evolutionary relationships of existing tailed phages, for relating newly discovered phages and for determining host/phage relationships. PMID:25240328

  7. CRISPR-Cas-Mediated Phage Resistance Enhances Horizontal Gene Transfer by Transduction.

    PubMed

    Watson, Bridget N J; Staals, Raymond H J; Fineran, Peter C

    2018-02-13

    A powerful contributor to prokaryotic evolution is horizontal gene transfer (HGT) through transformation, conjugation, and transduction, which can be advantageous, neutral, or detrimental to fitness. Bacteria and archaea control HGT and phage infection through CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) adaptive immunity. Although the benefits of resisting phage infection are evident, this can come at a cost of inhibiting the acquisition of other beneficial genes through HGT. Despite the ability of CRISPR-Cas to limit HGT through conjugation and transformation, its role in transduction is largely overlooked. Transduction is the phage-mediated transfer of bacterial DNA between cells and arguably has the greatest impact on HGT. We demonstrate that in Pectobacterium atrosepticum , CRISPR-Cas can inhibit the transduction of plasmids and chromosomal loci. In addition, we detected phage-mediated transfer of a large plant pathogenicity genomic island and show that CRISPR-Cas can inhibit its transduction. Despite these inhibitory effects of CRISPR-Cas on transduction, its more common role in phage resistance promotes rather than diminishes HGT via transduction by protecting bacteria from phage infection. This protective effect can also increase transduction of phage-sensitive members of mixed populations. CRISPR-Cas systems themselves display evidence of HGT, but little is known about their lateral dissemination between bacteria and whether transduction can contribute. We show that, through transduction, bacteria can acquire an entire chromosomal CRISPR-Cas system, including cas genes and phage-targeting spacers. We propose that the positive effect of CRISPR-Cas phage immunity on enhancing transduction surpasses the rarer cases where gene flow by transduction is restricted. IMPORTANCE The generation of genetic diversity through acquisition of DNA is a powerful contributor to microbial evolution and occurs through

  8. Bioinformatic analysis of phage AB3, a phiKMV-like virus infecting Acinetobacter baumannii.

    PubMed

    Zhang, J; Liu, X; Li, X-J

    2015-01-16

    The phages of Acinetobacter baumannii has drawn increasing attention because of the multi-drug resistance of A. baumanni. The aim of this study was to sequence Acinetobacter baumannii phage AB3 and conduct bioinformatic analysis to lay a foundation for genome remodeling and phage therapy. We isolated and sequenced A. baumannii phage AB3 and attempted to annotate and analyze its genome. The results showed that the genome is a double-stranded DNA with a total length of 31,185 base pairs (bp) and 97 open reading frames greater than 100 bp. The genome includes 28 predicted genes, of which 24 are homologous to phage AB1. The entire coding sequence is located on the negative strand, representing 90.8% of the total length. The G+C mol% was 39.18%, without areas of high G+C content over 200 bp in length. No GC island, tRNA gene, or repeated sequence was identified. Gene lengths were 120-3099 bp, with an average of 1011 bp. Six genes were found to be greater than 2000 bp in length. Genomic alignment and phylogenetic analysis of the RNA polymerase gene showed that similar to phage AB1, phage AB3 is a phiKMV-like virus in the T7 phage family.

  9. H-NS Mutation-Mediated CRISPR-Cas Activation Inhibits Phage Release and Toxin Production of Escherichia coli Stx2 Phage Lysogen.

    PubMed

    Fu, Qiang; Li, Shiyu; Wang, Zhaofei; Shan, Wenya; Ma, Jingjiao; Cheng, Yuqiang; Wang, Hengan; Yan, Yaxian; Sun, Jianhe

    2017-01-01

    Shiga toxin-converting bacteriophages (Stx phages) carry the stx gene and convert nonpathogenic bacterial strains into Shiga toxin-producing bacteria. There is limited understanding of the effect that an Escherichia coli ( E. coli ) clustered regularly interspaced short palindromic repeats (CRISPR)-Cas adaptive immune system has on Stx phage lysogen. We investigated heat-stable nucleoid-structuring (H-NS) mutation-mediated CRISPR-Cas activation and its effect on E. coli Stx2 phage lysogen. The Δ hns mutant (MG1655Δ hns ) of the E. coli K-12 strain MG1655 was obtained. The Δ hns mutant lysogen that was generated after Stx phage lysogenic infection had a repressed growth status and showed subdued group behavior, including biofilm formation and swarming motility, in comparison to the wild-type strain. The de-repression effect of the H-NS mutation on CRISPR-Cas activity was then verified. The results showed that cas gene expression was upregulated and the transformation efficiency of the wild-type CRISPR plasmids was decreased, which may indicate activation of the CRISPR-Cas system. Furthermore, the function of CRISPR-Cas on Stx2 phage lysogen was investigated by activating the CRISPR-Cas system, which contains an insertion of the protospacer regions of the Stx2 phage Min27. The phage release and toxin production of four lysogens harboring the engineered CRISPRs were investigated. Notably, in the supernatant of the Δ hns mutant lysogen harboring the Min27 spacer, both the progeny phage release and the toxin production were inhibited after mitomycin C induction. These observations demonstrate that the H-NS mutation-activated CRISPR-Cas system plays a role in modifying the effects of the Stx2 phage lysogen. Our findings indicated that H-NS mutation-mediated CRISPR-Cas activation in E. coli protects bacteria against Stx2 phage lysogeny by inhibiting the phage release and toxin production of the lysogen.

  10. Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mahony, Jennifer, E-mail: j.mahony@ucc.ie; Ainsworth, Stuart; Stockdale, Stephen

    Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes,more » and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.« less

  11. Youth often risk unsafe abortions.

    PubMed

    Barnett, B

    1993-10-01

    The topic of this article is the use of unsafe abortion for unwanted pregnancies among adolescents. The significance of unsafe abortion is identified as a high risk of serious health problems, such as infection, hemorrhage, infertility, and mortality, and as a strain on emergency room services. The World Health Organization estimates that at least 33% of all women seeking hospital care for abortion complications are aged under 20 years. 50 million abortions are estimated to be induced annually, of which 33% are illegal and almost 50% are performed outside the health care system. Complications are identified as occurring due to the procedure itself (perforation of the uterus, cervical lacerations, or hemorrhage) and due to incomplete abortion or introduction of bacteria into the uterus. Long-term complications include an increased risk of ectopic pregnancy, chronic pelvic infection, and infertility. Mortality from unsafe abortion is estimated at 1000/100,000 procedures. Safe abortion mortality is estimated at 0.6/100,000. When infertility results, some cultures ascribe an outcast status or marriages are prevented or prostitution is assured. The risk of complications is considered higher for adolescents. Adolescents tend to delay seeking an abortion, lack knowledge on where to go for a safe procedure, and delay seeking help for complications. Peer advice may be limited or inadequate knowledge. Five studies are cited that illustrate the impact of unsafe abortion on individuals and health care systems. Abortions may be desired due to fear of parental disapproval of the pregnancy, abandonment by the father, financial and emotional responsibilities of child rearing, expulsion from school, or inability to marry if the child is out of wedlock. Medical, legal, and social barriers may prevent women and girls from obtaining safe abortion. Parental permission is sometimes a requirement for safe abortion. Fears of judgmental or callous health personnel may be barriers to

  12. Phage T4 SegB protein is a homing endonuclease required for the preferred inheritance of T4 tRNA gene region occurring in co-infection with a related phage.

    PubMed

    Brok-Volchanskaya, Vera S; Kadyrov, Farid A; Sivogrivov, Dmitry E; Kolosov, Peter M; Sokolov, Andrey S; Shlyapnikov, Michael G; Kryukov, Valentine M; Granovsky, Igor E

    2008-04-01

    Homing endonucleases initiate nonreciprocal transfer of DNA segments containing their own genes and the flanking sequences by cleaving the recipient DNA. Bacteriophage T4 segB gene, which is located in a cluster of tRNA genes, encodes a protein of unknown function, homologous to homing endonucleases of the GIY-YIG family. We demonstrate that SegB protein is a site-specific endonuclease, which produces mostly 3' 2-nt protruding ends at its DNA cleavage site. Analysis of SegB cleavage sites suggests that SegB recognizes a 27-bp sequence. It contains 11-bp conserved sequence, which corresponds to a conserved motif of tRNA TpsiC stem-loop, whereas the remainder of the recognition site is rather degenerate. T4-related phages T2L, RB1 and RB3 contain tRNA gene regions that are homologous to that of phage T4 but lack segB gene and several tRNA genes. In co-infections of phages T4 and T2L, segB gene is inherited with nearly 100% of efficiency. The preferred inheritance depends absolutely on the segB gene integrity and is accompanied by the loss of the T2L tRNA gene region markers. We suggest that SegB is a homing endonuclease that functions to ensure spreading of its own gene and the surrounding tRNA genes among T4-related phages.

  13. Phage T4 SegB protein is a homing endonuclease required for the preferred inheritance of T4 tRNA gene region occurring in co-infection with a related phage

    PubMed Central

    Brok-Volchanskaya, Vera S.; Kadyrov, Farid A.; Sivogrivov, Dmitry E.; Kolosov, Peter M.; Sokolov, Andrey S.; Shlyapnikov, Michael G.; Kryukov, Valentine M.; Granovsky, Igor E.

    2008-01-01

    Homing endonucleases initiate nonreciprocal transfer of DNA segments containing their own genes and the flanking sequences by cleaving the recipient DNA. Bacteriophage T4 segB gene, which is located in a cluster of tRNA genes, encodes a protein of unknown function, homologous to homing endonucleases of the GIY-YIG family. We demonstrate that SegB protein is a site-specific endonuclease, which produces mostly 3′ 2-nt protruding ends at its DNA cleavage site. Analysis of SegB cleavage sites suggests that SegB recognizes a 27-bp sequence. It contains 11-bp conserved sequence, which corresponds to a conserved motif of tRNA TψC stem-loop, whereas the remainder of the recognition site is rather degenerate. T4-related phages T2L, RB1 and RB3 contain tRNA gene regions that are homologous to that of phage T4 but lack segB gene and several tRNA genes. In co-infections of phages T4 and T2L, segB gene is inherited with nearly 100% of efficiency. The preferred inheritance depends absolutely on the segB gene integrity and is accompanied by the loss of the T2L tRNA gene region markers. We suggest that SegB is a homing endonuclease that functions to ensure spreading of its own gene and the surrounding tRNA genes among T4-related phages. PMID:18281701

  14. Effect of Antiviral Agents in Equine Abortion Virus-Infected Hamsters1

    PubMed Central

    Lieberman, Melvin; Pascale, Andrea; Schafer, Thomas W.; Came, Paul E.

    1972-01-01

    Equine abortion virus, a member of the herpesvirus group, produces a lethal infection in hamsters. With this system, the protective effect of certain inhibitors of deoxyribonucleic acid viruses, inducers of interferon and exogenous interferon, was evaluated. Of the various agents studied, 9-β-d-arabinofuranosyladenine markedly suppressed mortality, and 5-iodo-2′-deoxyuridine, distamycin A, and N-ethylisatin β-thiosemicarbazone were inactive. Of the inducers tested, statolon, ultraviolet-irradiated Newcastle disease virus, and polyriboinosinic:polyribocytidylic acid (poly I:C) were protective, and endotoxin, polyacrylic acid, and polymethacrylic acid did not protect. Administration of exogenous interferon did not afford protection. Statolon and ultraviolet-irradiated Newcastle disease virus induced circulating interferon in hamsters, whereas poly I:C, endotoxin, and polyacrylic acid did not produce interferon. Because of the severity of the disease produced in hamsters by equine abortion virus, lack of protective activity by an agent in this system should not preclude possible efficacy against other members of the herpesvirus group. PMID:4376907

  15. In silico analysis of AHJD-like viruses, Staphylococcus aureus phages S24-1 and S13′, and study of phage S24-1 adsorption

    PubMed Central

    Uchiyama, Jumpei; Takemura-Uchiyama, Iyo; Kato, Shin-ichiro; Sato, Miho; Ujihara, Takako; Matsui, Hidehito; Hanaki, Hideaki; Daibata, Masanori; Matsuzaki, Shigenobu

    2014-01-01

    Staphylococcus aureus is a clinically important bacterium that is commensal in both humans and animals. Bacteriophage (phage) attachment to the host bacterial surface is an important process during phage infection, which involves interactions between phage receptor-binding proteins and host receptor molecules. However, little information is available on the receptor-binding protein of S. aureus phages. S. aureus virulent phages S24-1 and S13′ (family Podoviridae, genus AHJD-like viruses) were isolated from sewage. In the present study, we investigated the receptor-binding protein of AHJD-like viruses using phage S24-1. First, based on a comparative genomic analysis of phages S24-1 and S13′, open reading frame 16 (ORF16) of phage S24-1 was speculated to be the receptor-binding protein, which possibly determines the host range. Second, we demonstrated that this was the receptor-binding protein of phage S24-1. Third, our study suggested that wall teichoic acids in the cell walls of S. aureus are the main receptor molecules for ORF16 and phage S24-1. Finally, the C-terminal region of ORF16 may be essential for binding to S. aureus. These results strongly suggest that ORF16 of phage S24-1 and its homologs may be the receptor-binding proteins of AHJD-like viruses. PMID:24591378

  16. Hybrid Nanomaterial Complexes for Advanced Phage-guided Gene Delivery

    PubMed Central

    Yata, Teerapong; Lee, Koon-Yang; Dharakul, Tararaj; Songsivilai, Sirirurg; Bismarck, Alexander; Mintz, Paul J; Hajitou, Amin

    2014-01-01

    Developing nanomaterials that are effective, safe, and selective for gene transfer applications is challenging. Bacteriophages (phage), viruses that infect bacteria only, have shown promise for targeted gene transfer applications. Unfortunately, limited progress has been achieved in improving their potential to overcome mammalian cellular barriers. We hypothesized that chemical modification of the bacteriophage capsid could be applied to improve targeted gene delivery by phage vectors into mammalian cells. Here, we introduce a novel hybrid system consisting of two classes of nanomaterial systems, cationic polymers and M13 bacteriophage virus particles genetically engineered to display a tumor-targeting ligand and carry a transgene cassette. We demonstrate that the phage complex with cationic polymers generates positively charged phage and large aggregates that show enhanced cell surface attachment, buffering capacity, and improved transgene expression while retaining cell type specificity. Moreover, phage/polymer complexes carrying a therapeutic gene achieve greater cancer cell killing than phage alone. This new class of hybrid nanomaterial platform can advance targeted gene delivery applications by bacteriophage. PMID:25118171

  17. Anti-CRISPR proteins: Counterattack of phages on bacterial defense (CRISPR/Cas) system.

    PubMed

    Chaudhary, Kulbhushan; Chattopadhyay, Anirudha; Pratap, Dharmendra

    2018-01-01

    Since the dawn of life there is a never ending strife between bacteria and phages. Both are perpetually changing their strategies to take over each other. CRISPR/Cas is the most widespread defense system used by bacteria against mobile genetic elements (MGEs) such as phages, cojugative palsmids, transoposons, and pathogenicity islands. This system utilizes small guide RNA molecules to protect against phages infection and invasion by MGEs. Phages circumvent to these antiviral barriers by point mutation in PAM (protospacer-adjacent motif) sequence, genome rearrangements and by using anti-CRISPR proteins. © 2017 Wiley Periodicals, Inc.

  18. Comparison of abortion and infection after experimental challenge of pregnant bison and cattle with Brucella abortus strain 2308

    USDA-ARS?s Scientific Manuscript database

    A comparative study was conducted using data from naive bison (n=45) and cattle (n=46) from 8 and 6 studies, respectively, in which a standardized Brucella abortus strain 2308 experimental challenge was administered. The incidence of abortion, fetal infection, uterine or mammary infection, or infec...

  19. Genome of a SAR116 bacteriophage shows the prevalence of this phage type in the oceans.

    PubMed

    Kang, Ilnam; Oh, Hyun-Myung; Kang, Dongmin; Cho, Jang-Cheon

    2013-07-23

    The abundance, genetic diversity, and crucial ecological and evolutionary roles of marine phages have prompted a large number of metagenomic studies. However, obtaining a thorough understanding of marine phages has been hampered by the low number of phage isolates infecting major bacterial groups other than cyanophages and pelagiphages. Therefore, there is an urgent requirement for the isolation of phages that infect abundant marine bacterial groups. In this study, we isolated and characterized HMO-2011, a phage infecting a bacterium of the SAR116 clade, one of the most abundant marine bacterial lineages. HMO-2011, which infects "Candidatus Puniceispirillum marinum" strain IMCC1322, has an ~55-kb dsDNA genome that harbors many genes with novel features rarely found in cultured organisms, including genes encoding a DNA polymerase with a partial DnaJ central domain and an atypical methanesulfonate monooxygenase. Furthermore, homologs of nearly all HMO-2011 genes were predominantly found in marine metagenomes rather than cultured organisms, suggesting the novelty of HMO-2011 and the prevalence of this phage type in the oceans. A significant number of the viral metagenome sequences obtained from the ocean surface were best assigned to the HMO-2011 genome. The number of reads assigned to HMO-2011 accounted for 10.3%-25.3% of the total reads assigned to viruses in seven viromes from the Pacific and Indian Oceans, making the HMO-2011 genome the most or second-most frequently assigned viral genome. Given its ability to infect the abundant SAR116 clade and its widespread distribution, Puniceispirillum phage HMO-2011 could be an important resource for marine virus research.

  20. Abortion - medical

    MedlinePlus

    ... several hours. Your provider may prescribe medicine for pain and nausea if needed to ease your discomfort during this process. ... Risks of medical abortion include: Continued bleeding Diarrhea ... body, making surgery necessary Infection Nausea Pain Vomiting

  1. Phages Preying on Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis: Past, Present and Future

    PubMed Central

    Gillis, Annika; Mahillon, Jacques

    2014-01-01

    Many bacteriophages (phages) have been widely studied due to their major role in virulence evolution of bacterial pathogens. However, less attention has been paid to phages preying on bacteria from the Bacillus cereus group and their contribution to the bacterial genetic pool has been disregarded. Therefore, this review brings together the main information for the B. cereus group phages, from their discovery to their modern biotechnological applications. A special focus is given to phages infecting Bacillus anthracis, B. cereus and Bacillus thuringiensis. These phages belong to the Myoviridae, Siphoviridae, Podoviridae and Tectiviridae families. For the sake of clarity, several phage categories have been made according to significant characteristics such as lifestyles and lysogenic states. The main categories comprise the transducing phages, phages with a chromosomal or plasmidial prophage state, γ-like phages and jumbo-phages. The current genomic characterization of some of these phages is also addressed throughout this work and some promising applications are discussed here. PMID:25010767

  2. A tale of tails: Sialidase is key to success in a model of phage therapy against K1-capsulated Escherichia coli.

    PubMed

    Bull, J J; Vimr, E R; Molineux, I J

    2010-03-01

    Prior studies treating mice infected with Escherichia coli O18:K1:H7 observed that phages requiring the K1 capsule for infection (K1-dep) were superior to capsule-independent (K1-ind) phages. We show that three K1-ind phages all have low fitness when grown on cells in serum whereas fitnesses of four K1-dep phages were high. The difference is serum-specific, as fitnesses in broth overlapped. Sialidase activity was associated with all K1-dep virions tested but no K1-ind virions, a phenotype supported by sequence analyses. Adding endosialidase to cells infected with K1-ind phage increased fitness in serum by enhancing productive infection after adsorption. We propose that virion sialidase activity is the primary determinant of high fitness on cells grown in serum, and thus in a mammalian host. Although the benefit of sialidase is specific to K1-capsulated bacteria, this study may provide a scientific rationale for selecting phages for therapeutic use in many systemic infections. Copyright 2009 Elsevier Inc. All rights reserved.

  3. Phage display as a promising approach for vaccine development.

    PubMed

    Aghebati-Maleki, Leili; Bakhshinejad, Babak; Baradaran, Behzad; Motallebnezhad, Morteza; Aghebati-Maleki, Ali; Nickho, Hamid; Yousefi, Mehdi; Majidi, Jafar

    2016-09-29

    Bacteriophages are specific antagonists to bacterial hosts. These viral entities have attracted growing interest as optimal vaccine delivery vehicles. Phages are well-matched for vaccine design due to being highly stable under harsh environmental conditions, simple and inexpensive large scale production, and potent adjuvant capacities. Phage vaccines have efficient immunostimulatory effects and present a high safety profile because these viruses have made a constant relationship with the mammalian body during a long-standing evolutionary period. The birth of phage display technology has been a turning point in the development of phage-based vaccines. Phage display vaccines are made by expressing multiple copies of an antigen on the surface of immunogenic phage particles, thereby eliciting a powerful and effective immune response. Also, the ability to produce combinatorial peptide libraries with a highly diverse pool of randomized ligands has transformed phage display into a straightforward, versatile and high throughput screening methodology for the identification of potential vaccine candidates against different diseases in particular microbial infections. These libraries can be conveniently screened through an affinity selection-based strategy called biopanning against a wide variety of targets for the selection of mimotopes with high antigenicity and immunogenicity. Also, they can be panned against the antiserum of convalescent individuals to recognize novel peptidomimetics of pathogen-related epitopes. Phage display has represented enormous promise for finding new strategies of vaccine discovery and production and current breakthroughs promise a brilliant future for the development of different phage-based vaccine platforms.

  4. Episodic acyclovir therapy to abort recurrent attacks of genital herpes simplex infection.

    PubMed

    Whatley, J D; Thin, R N

    1991-05-01

    Frequent recurrence of genital herpes simplex infection can be a distressing condition. Continuous suppressive oral acyclovir is effective but expensive. Hitherto episodic therapy has given disappointing results. An open comparative study of patient initiated therapy is reported here. Acyclovir 200 mg five times daily for five days aborted 44% of recurrences and shortened 38% by greater than or equal to 50%, giving useful response in 82% of 34 recurrences. Acyclovir 400 mg twice daily for five days aborted 60% and shortened 17% giving useful benefit in 77% of 20 recurrences. Acyclovir 200 mg twice a day for five days gave unsatisfactory results. Patients were selected for frequent recurrences and a recognized prodrome, and care was taken to help to identify early prodromal symptoms. In these patients acyclovir in dosages of 200 mg five times daily for five days and 400 mg bd for five days proved convenient and cost effective.

  5. Application of Bacteroides fragilis phage as an alternative indicator of sewage pollution in Tampa Bay, Florida

    USGS Publications Warehouse

    McLaughlin, M.R.; Rose, J.B.

    2006-01-01

    Traditional fecal coliform bacterial indicators have been found to be severely limited in determining the significance and sources of fecal contamination in ambient waters of tropical and subtropical regions. The bacteriophages that infect Bacteroides fragilis have been suggested as better fecal indicators and at least one type may be human specific. In this study, the phages that infect B. fragilis host RYC2056 (RYC), including phage B56-3, and host ATCC 51477-HSP40 (HSP), including the human specific phage B40-8, were evaluated in the drainage basins of Tampa Bay, 7 samples (n = 62), or 11%, tested positive for the presence of phages infecting the host HSP, whereas 28 samples, or 45%, tested positive using the host RYC. A survival study was also done to compare the persistence of phages B56-3 and B40-8 to MS2 coliphage in seawater at various temperatures. The decay rates for MS2 were 0.239 log 10 d-1 at 10??C, but increased to 0.896 at 20??C and 2.62 log10 d-1 at 30??C. The two B. fragilis phages persisted much longer in the seawater compared to the coliphage and showed little variation between the temperatures. All sewage influents sampled from area wastewater treatment plants contained phages that infected the two B. fragilis hosts at levels from 1.2 ?? 104 to 1.11 ?? 10 5 pfu 100 ml-1 for host RYC and 67 to 350 pfu 100 ml -1 for host HSP. Of the 7 chlorinated effluent samples tested, 3 were positive for the presence of the phage using the host RYC and the phage enrichment method, with levels estimated to be <10 pfu 100 ml-1. No phages were detected using the host HSP in the treated sewage effluent. Coliphages were found in 3 of the 7 effluent samples at a range of 30 to 1.2 ?? 103 pfu 100 ml-1. ?? 2006 Estuarine Research Federation.

  6. The action of Escherichia coli CRISPR–Cas system on lytic bacteriophages with different lifestyles and development strategies

    PubMed Central

    Strotskaya, Alexandra; Savitskaya, Ekaterina; Metlitskaya, Anastasia; Morozova, Natalia; Datsenko, Kirill A.; Semenova, Ekaterina

    2017-01-01

    Abstract CRISPR–Cas systems provide prokaryotes with adaptive defense against bacteriophage infections. Given an enormous variety of strategies used by phages to overcome their hosts, one can expect that the efficiency of protective action of CRISPR–Cas systems against different viruses should vary. Here, we created a collection of Escherichia coli strains with type I-E CRISPR–Cas system targeting various positions in the genomes of bacteriophages λ, T5, T7, T4 and R1-37 and investigated the ability of these strains to resist the infection and acquire additional CRISPR spacers from the infecting phage. We find that the efficiency of CRISPR–Cas targeting by the host is determined by phage life style, the positions of the targeted protospacer within the genome, and the state of phage DNA. The results also suggest that during infection by lytic phages that are susceptible to CRISPR interference, CRISPR–Cas does not act as a true immunity system that saves the infected cell but rather enforces an abortive infection pathway leading to infected cell death with no phage progeny release. PMID:28130424

  7. Antisense RNA protects mRNA from RNase E degradation by RNA–RNA duplex formation during phage infection

    PubMed Central

    Stazic, Damir; Lindell, Debbie; Steglich, Claudia

    2011-01-01

    The ecologically important cyanobacterium Prochlorococcus possesses the smallest genome among oxyphototrophs, with a reduced suite of protein regulators and a disproportionately high number of regulatory RNAs. Many of these are asRNAs, raising the question whether they modulate gene expression through the protection of mRNA from RNase E degradation. To address this question, we produced recombinant RNase E from Prochlorococcus sp. MED4, which functions optimally at 12 mM Mg2+, pH 9 and 35°C. RNase E cleavage assays were performed with this recombinant protein to assess enzyme activity in the presence of single- or double-stranded RNA substrates. We found that extraordinarily long asRNAs of 3.5 and 7 kb protect a set of mRNAs from RNase E degradation that accumulate during phage infection. These asRNA–mRNA duplex formations mask single-stranded recognition sites of RNase E, leading to increased stability of the mRNAs. Such interactions directly modulate RNA stability and provide an explanation for enhanced transcript abundance of certain mRNAs during phage infection. Protection from RNase E-triggered RNA decay may constitute a hitherto unknown regulatory function of bacterial cis-asRNAs, impacting gene expression. PMID:21325266

  8. Antisense RNA protects mRNA from RNase E degradation by RNA-RNA duplex formation during phage infection.

    PubMed

    Stazic, Damir; Lindell, Debbie; Steglich, Claudia

    2011-06-01

    The ecologically important cyanobacterium Prochlorococcus possesses the smallest genome among oxyphototrophs, with a reduced suite of protein regulators and a disproportionately high number of regulatory RNAs. Many of these are asRNAs, raising the question whether they modulate gene expression through the protection of mRNA from RNase E degradation. To address this question, we produced recombinant RNase E from Prochlorococcus sp. MED4, which functions optimally at 12 mM Mg(2+), pH 9 and 35°C. RNase E cleavage assays were performed with this recombinant protein to assess enzyme activity in the presence of single- or double-stranded RNA substrates. We found that extraordinarily long asRNAs of 3.5 and 7 kb protect a set of mRNAs from RNase E degradation that accumulate during phage infection. These asRNA-mRNA duplex formations mask single-stranded recognition sites of RNase E, leading to increased stability of the mRNAs. Such interactions directly modulate RNA stability and provide an explanation for enhanced transcript abundance of certain mRNAs during phage infection. Protection from RNase E-triggered RNA decay may constitute a hitherto unknown regulatory function of bacterial cis-asRNAs, impacting gene expression.

  9. Genomic analysis of WCP30 Phage of Weissella cibaria for Dairy Fermented Foods.

    PubMed

    Lee, Young-Duck; Park, Jong-Hyun

    2017-01-01

    In this study, we report the morphogenetic analysis and genome sequence of a new WCP30 phage of Weissella cibaria , isolated from a fermented food. Based on its morphology, as observed by transmission electron microscopy, WCP30 phage belongs to the family Siphoviridae . Genomic analysis of WCP30 phage showed that it had a 33,697-bp double-stranded DNA genome with 41.2% G+C content. Bioinformatics analysis of the genome revealed 35 open reading frames. A BLASTN search showed that WCP30 phage had low sequence similarity compared to other phages infecting lactic acid bacteria. This is the first report of the morphological features and complete genome sequence of WCP30 phage, which may be useful for controlling the fermentation of dairy foods.

  10. Phage-Enabled Nanomedicine: From Probes to Therapeutics in Precision Medicine.

    PubMed

    Sunderland, Kegan S; Yang, Mingying; Mao, Chuanbin

    2017-02-13

    Both lytic and temperate bacteriophages (phages) can be applied in nanomedicine, in particular, as nanoprobes for precise disease diagnosis and nanotherapeutics for targeted disease treatment. Since phages are bacteria-specific viruses, they do not naturally infect eukaryotic cells and are not toxic to them. They can be genetically engineered to target nanoparticles, cells, tissues, and organs, and can also be modified with functional abiotic nanomaterials for disease diagnosis and treatment. This Review will summarize the current use of phage structures in many aspects of precision nanomedicine, including ultrasensitive biomarker detection, enhanced bioimaging for disease diagnosis, targeted drug and gene delivery, directed stem cell differentiation, accelerated tissue formation, effective vaccination, and nanotherapeutics for targeted disease treatment. We will also propose future directions in the area of phage-based nanomedicines, and discuss the state of phage-based clinical trials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Chromato-panning: an efficient new mode of identifying suitable ligands from phage display libraries

    PubMed Central

    Noppe, Wim; Plieva, Fatima; Galaev, Igor Yu; Pottel, Hans; Deckmyn, Hans; Mattiasson, Bo

    2009-01-01

    Background Phage Display technology is a well established technique for high throughput screening of affinity ligands. Here we describe a new compact chromato-panning procedure for selection of suitable binders from a phage peptide display library. Results Both phages and E. coli cells pass non-hindered through the interconnected pores of macroporous gel, so called cryogel. After coupling a ligand to a monolithic cryogel column, the phage library was applied on the column and non-bound phages were washed out. The selection of strong phage-binders was achieved already after the first panning cycle due to the efficient separation of phage-binders from phage-non-binders in chromatographic mode rather than in batch mode as in traditional biopanning procedures. E. coli cells were applied on the column for infection with the specifically bound phages. Conclusion Chromato-panning allows combining several steps of the panning procedure resulting in 4–8 fold decrease of total time needed for phage selection. PMID:19292898

  12. Progress toward a reduced phage genetic code.

    PubMed

    Yao, Anzhi; Reed, Sean A; Koh, Minseob; Yu, Chenguang; Luo, Xiaozhou; Mehta, Angad P; Schultz, Peter G

    2018-03-26

    All known living organisms use at least 20 amino acids as the basic building blocks of life. Efforts to reduce the number of building blocks in a replicating system to below the 20 canonical amino acids have not been successful to date. In this work, we use filamentous phage as a model system to investigate the feasibility of removing methionine (Met) from the proteome. We show that all 24 elongation Met sites in the M13 phage genome can be replaced by other canonical amino acids. Most of these changes involve substitution of methionine by leucine (Leu), but in some cases additional compensatory mutations are required. Combining Met substituted sites in the proteome generally led to lower viability/infectivity of the mutant phages, which remains the major challenge in eliminating all methionines from the phage proteome. To date a total of 15 (out of all 24) elongation Mets have been simultaneously deleted from the M13 proteome, providing a useful foundation for future efforts to minimize the genetic code. Copyright © 2018. Published by Elsevier Ltd.

  13. Flagellin inhibits Myoviridae phage phiCTX infection of Pseudomonas aeruginosa strain GuA18: purification and mapping of binding site.

    PubMed

    Geiben-Lynn, R; Sauber, K; Lutz, F

    2001-11-01

    PhiCTX is a double-stranded DNA phage of the Myoviridae family that converts Pseudomonas aeruginosa into a cytotoxin producer. A 42-kDa phiCTX-inhibiting protein was purified from the outer membrane fraction of P. aeruginosa strain GuA18 by octyl-beta-glucoside extraction, DEAE-chromatography, and mono-Q HPLC. This protein had an isoelectric point of 5.4 and bound specifically [125I]-labeled phiCTX. The N-terminal amino acid sequence of six out of seven Lys-C fragments was highly similar (87%) to that of the entire of type-a flagellin of P. aeruginosa strain PAK. At a concentration of 14 nM, purified flagellin protein caused a 50% decrease in the phage titer after a 20-min incubation at 37 degrees C (PhI50). The presence of ethanol was necessary to reconstitute the inhibitory activity. In contrast, no ethanol treatment was necessary for the inhibitory activity of the sheared flagellin filaments from P. aeruginosa strain GuA18, which consists of the 42-kDa flagellin subunits and the synthesized 17-mer phage-binding-peptide NGSNSDSERTALNGEAK, representing flagellin residues 100-116 of P. aeruginosa strain PAK. The PhI50 was 10 nM and 200 nM, respectively. Antisera against the flagellin filament protein as well as against the 17-mer peptide neutralized phage infection. These results indicated that the amino acid region 100-116 of the flagellin subunit of strain GuA18 is involved in phiCTX binding. This region might play a role in phage attachment.

  14. Virucidal Influence of Ionic Liquids on Phages P100 and MS2

    PubMed Central

    Fister, Susanne; Mester, Patrick; Sommer, Julia; Witte, Anna K.; Kalb, Roland; Wagner, Martin; Rossmanith, Peter

    2017-01-01

    An increasing number of publications describe the potential of ionic liquids (ILs) as novel antimicrobials, antibacterial coatings and even as active pharmaceutical ingredients. Nevertheless, a major research area, notably their impact on viruses, has so far been neglected. Consequently the aim of this study was to examine the effects of ILs on the infectivity of viruses. A systematic analysis to investigate the effects of defined structural elements of ILs on virus activity was performed using 55 ILs. All structure activity relationships (SARs) were tested on the human norovirus surrogate phage MS2 and phage P100 representing non-enveloped DNA viruses. Results demonstrate that IL SAR conclusions, established for prokaryotes and eukaryotes, are not readily applicable to the examined phages. A virus-type-dependent IL influence was also apparent. Overall, four ILs, covering different structural elements, were found to reduce phage P100 infectivity by ≥4 log10 units, indicating a virucidal effect, whereas the highest reduction for phage MS2 was about 3 log10 units. Results indicate that future applications of ILs as virucidal agents will require development of novel SARs and the obtained results serve as a good starting point for future studies. PMID:28883814

  15. The genome of the Lactobacillus sanfranciscensis temperate phage EV3

    PubMed Central

    2013-01-01

    Background Bacteriophages infection modulates microbial consortia and transduction is one of the most important mechanism involved in the bacterial evolution. However, phage contamination brings food fermentations to a halt causing economic setbacks. The number of phage genome sequences of lactic acid bacteria especially of lactobacilli is still limited. We analysed the genome of a temperate phage active on Lactobacillus sanfranciscensis, the predominant strain in type I sourdough fermentations. Results Sequencing of the DNA of EV3 phage revealed a genome of 34,834 bp and a G + C content of 36.45%. Of the 43 open reading frames (ORFs) identified, all but eight shared homology with other phages of lactobacilli. A similar genomic organization and mosaic pattern of identities align EV3 with the closely related Lactobacillus vaginalis ATCC 49540 prophage. Four unknown ORFs that had no homologies in the databases or predicted functions were identified. Notably, EV3 encodes a putative dextranase. Conclusions EV3 is the first L. sanfranciscensis phage that has been completely sequenced so far. PMID:24308641

  16. Cerebral Candidal Abscess and Bovine Viral Diarrhoea Virus Infection in an Aborted Bovine Fetus.

    PubMed

    Vilander, A C; Niles, G A; Frank, C B

    2016-01-01

    Candida species are opportunistic fungi associated with immunosuppression and are the most commonly isolated fungal pathogens from the human central nervous system. Invasive candidiasis is reported uncommonly in animals and there have only been two reports of candidal infection of the brain. This report presents a case of a cerebral candidal abscess in an aborted late-term calf co-infected with bovine viral diarrhoea virus. Candida etchellsii, a species not previously identified as pathogenic, was identified as the causative agent by polymerase chain reaction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Sheep polyclonal antibody to map Haemonchus contortus mimotopes using phage display library.

    PubMed

    Buzatti, Andréia; Fernandez, Arnielis Diaz; Arenal, Amilcar; Pereira, Erlán; Monteiro, Alda Lucia Gomes; Molento, Marcelo Beltrão

    2018-05-24

    The aim of this study was to evaluate phage display technology for mapping Haemonchus contortus mimotopes. We screened the PhD-7 Phage Display Peptide Library Kit with a sheep polyclonal antibody against H. contortus. After four rounds of selection, 50 phage peptide clones were selected by biopanning and sequenced. Two clones displaying peptide mimotopes of H. contortus proteins were chosen for sheep immunization: clone 6 - mimotope of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and clone 17 - mimotope of a disorganized muscle family member (Dim 1). Twelve sheep were allocated into 3 groups of 4 animals as follow: G1: control group; G2/GAPDH: immunized with clone 6; and G3/Dim1: immunized with clone 17. Four immunizations were performed at intervals of seven days (0, 7, 14, and 21 days). On day 28 post initial vaccination, all groups were orally challenged with 2500 H. contortus infective larvae. The mimotope peptides selected by phage display were recognized by IgG from sheep naturaly infected with H. contortus. The immunization protocol showed an increasein IgG anti-M13 phage titers, but no effect was observed in IgG-specific for the anti-mimotope peptides. This is the first report of successful use of a phage display library for the identification of mimotopes of H. contortus proteins.

  18. Isolation and characterization of a T7-like lytic phage for Pseudomonas fluorescens.

    PubMed

    Sillankorva, Sanna; Neubauer, Peter; Azeredo, Joana

    2008-10-27

    Despite the proven relevance of Pseudomonas fluorescens as a spoilage microorganism in milk, fresh meats and refrigerated food products and the recognized potential of bacteriophages as sanitation agents, so far no phages specific for P. fluorescens isolates from dairy industry have been closely characterized in view of their lytic efficiency. Here we describe the isolation and characterization of a lytic phage capable to infect a variety of P. fluorescens strains isolated from Portuguese and United States dairy industries. Several phages were isolated which showed a different host spectrum and efficiency of lysis. One of the phages, phage phiIBB-PF7A, was studied in detail due to its efficient lysis of a wide spectrum of P. fluorescens strains and ribotypes. Phage phiIBB-PF7A with a head diameter of about 63 nm and a tail size of about 13 x 8 nm belongs morphologically to the Podoviridae family and resembles a typical T7-like phage, as analyzed by transmission electron microscopy (TEM). The phage growth cycle with a detected latent period of 15 min, an eclipse period of 10 min, a burst size of 153 plaque forming units per infected cell, its genome size of approximately 42 kbp, and the size and N-terminal sequence of one of the protein bands, which gave similarity to the major capsid protein 10A, are consistent with this classification. The isolated T7-like phage, phage phiIBB-PF7A, is fast and efficient in lysing different P. fluorescens strains and may be a good candidate to be used as a sanitation agent to control the prevalence of spoilage causing P. fluorescens strains in dairy and food related environments.

  19. The Impact of Prophage on the Equilibria and Stability of Phage and Host

    NASA Astrophysics Data System (ADS)

    Yu, Pei; Nadeem, Alina; Wahl, Lindi M.

    2017-06-01

    In this paper, we present a bacteriophage model that includes prophage, that is, phage genomes that are incorporated into the host cell genome. The general model is described by an 18-dimensional system of ordinary differential equations. This study focuses on asymptotic behaviour of the model, and thus the system is reduced to a simple six-dimensional model, involving uninfected host cells, infected host cells and phage. We use dynamical system theory to explore the dynamic behaviour of the model, studying in particular the impact of prophage on the equilibria and stability of phage and host. We employ bifurcation and stability theory, centre manifold and normal form theory to show that the system has multiple equilibrium solutions which undergo a series of bifurcations, finally leading to oscillating motions. Numerical simulations are presented to illustrate and confirm the analytical predictions. The results of this study indicate that in some parameter regimes, the host cell population may drive the phage to extinction through diversification, that is, if multiple types of host emerge; this prediction holds even if the phage population is likewise diverse. This parameter regime is restricted, however, if infecting phage are able to recombine with prophage sequences in the host cell genome.

  20. A comparative study of induced abortions before and after legalization of abortions.

    PubMed

    Malhotra, S; Devi, P K

    1979-06-01

    Abortion was legalized in many states in India in April 1972. This study deals with 2 groups of patients admitted to P.G.I., Chadigarh, with problems of induced septic abortion. Group 1 consisted of 88 patients admitted during the 2 1/2 year period from 1 July 1969 to 31 December 1971, before the legalization of abortion. Group 2 consists of 133 patients admitted during the 2 1/2 year period from 1 July 1973 to 31 December 1975. 1 year after the new abortion law had been in force. Not only has there been an increase in the total number of patients, there has been an increase in the severity of infection. Evidently, the liberalization of the law has encouraged more patients to seek abortions and has encouraged more doctors, lacking proper qualifications, to perform them. The morbidity and mortality with induced septic abortion can only be reduced if enough public propaganda makes the people especially in rural areas conscious of the hazards of induced abortion by "dais" and unqualified personnel, simultaneously making them aware of the provision of law and facilities available at different centers. Meanwhile, the law against unskilled and untrained personnel should be rigorously enforced.

  1. Engineered phages for electronics.

    PubMed

    Cui, Yue

    2016-11-15

    Phages are traditionally widely studied in biology and chemistry. In recent years, engineered phages have attracted significant attentions for functionalization or construction of electronic devices, due to their specific binding, catalytic, nucleating or electronic properties. To apply the engineered phages in electronics, these are a number of interesting questions: how to engineer phages for electronics? How are the engineered phages characterized? How to assemble materials with engineered phages? How are the engineered phages micro or nanopatterned? What are the strategies to construct electronics devices with engineered phages? This review will highlight the early attempts to address these questions and explore the fundamental and practical aspects of engineered phages in electronics, including the approaches for selection or expression of specific peptides on phage coat proteins, characterization of engineered phages in electronics, assembly of electronic materials, patterning of engineered phages, and construction of electronic devices. It provides the methodologies and opens up ex-cit-ing op-por-tu-ni-ties for the development of a variety of new electronic materials and devices based on engineered phages for future applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Phage-Phagocyte Interactions and Their Implications for Phage Application as Therapeutics.

    PubMed

    Jończyk-Matysiak, Ewa; Weber-Dąbrowska, Beata; Owczarek, Barbara; Międzybrodzki, Ryszard; Łusiak-Szelachowska, Marzanna; Łodej, Norbert; Górski, Andrzej

    2017-06-14

    Phagocytes are the main component of innate immunity. They remove pathogens and particles from organisms using their bactericidal tools in the form of both reactive oxygen species and degrading enzymes-contained in granules-that are potentially toxic proteins. Therefore, it is important to investigate the possible interactions between phages and immune cells and avoid any phage side effects on them. Recent progress in knowledge concerning the influence of phages on phagocytes is also important as such interactions may shape the immune response. In this review we have summarized the current knowledge on phage interactions with phagocytes described so far and their potential implications for phage therapy . The data suggesting that phage do not downregulate important phagocyte functions are especially relevant for the concept of phage therapy.

  3. The Human Gut Phage Community and Its Implications for Health and Disease.

    PubMed

    Manrique, Pilar; Dills, Michael; Young, Mark J

    2017-06-08

    In this review, we assess our current understanding of the role of bacteriophages infecting the human gut bacterial community in health and disease. In general, bacteriophages contribute to the structure of their microbial communities by driving host and viral diversification, bacterial evolution, and by expanding the functional diversity of ecosystems. Gut bacteriophages are an ensemble of unique and shared phages in individuals, which encompass temperate phages found predominately as prophage in gut bacteria (prophage reservoir) and lytic phages. In healthy individuals, only a small fraction of the prophage reservoir is activated and found as extracellular phages. Phage community dysbiosis is characterized by a shift in the activated prophage community or an increase of lytic phages, and has been correlated with disease, suggesting that a proper balance between lysis and lysogeny is needed to maintain health. Consequently, the concept of microbial dysbiosis might be extended to the phage component of the microbiome as well. Understanding the dynamics and mechanisms to restore balance after dysbiosis is an active area of research. The use of phage transplants to re-establish health suggests that phages can be used as disease treatment. Such advances represent milestones in our understanding of gut phages in human health and should fuel research on their role in health and disease.

  4. Targeting mammalian organelles with internalizing phage (iPhage) libraries

    PubMed Central

    Rangel, Roberto; Dobroff, Andrey S.; Guzman-Rojas, Liliana; Salmeron, Carolina C.; Gelovani, Juri G.; Sidman, Richard L.; Pasqualini, Renata; Arap, Wadih

    2015-01-01

    Techniques largely used for protein interaction studies and discovery of intracellular receptors, such as affinity capture complex purification and yeast two-hybrid, may produce inaccurate datasets due to protein insolubility, transient or weak protein interactions, or irrelevant intracellular context. A versatile tool to overcome these limitations as well as to potentially create vaccines and engineer peptides and antibodies as targeted diagnostic and therapeutic agents, is the phage display technique. We have recently developed a new technology for screening internalizing phage (iPhage) vectors and libraries utilizing a ligand/receptor-independent mechanism to penetrate eukaryotic cells. iPhage particles provide a unique discovery platform for combinatorial intracellular targeting of organelle ligands along with their corresponding receptors and to fingerprint functional protein domains in living cells. Here we explain the design, cloning, construction, and production of iPhage-based vectors and libraries, along with basic ligand-receptor identification and validation methodologies for organelle receptors. An iPhage library screening can be performed in ~8 weeks. PMID:24030441

  5. Is curettage needed for uncomplicated incomplete spontaneous abortion?

    PubMed

    Ballagh, S A; Harris, H A; Demasio, K

    1998-11-01

    Spontaneous abortion occurs in 15% to 20% of all human pregnancies. Since the late 1800s, the management of incomplete spontaneous abortion has focused on using curettage to empty the uterus as quickly as possible. This practice began to reduce blood loss and infection and has been unquestioned for 4 decades. In today's medical climate, few spontaneous abortions are the resuslt of illegal manipulation, given the availability of legal pregnancy termination. Antibiotics and transfusions are available, should complications arise in conservatively managed cases. Two prospective randomized trials suggest that conservative management may be advantageous for women who have stable vital signs without evidence of infection. They will have fewer perforations and, possibly, fewer infections and uterine synechiae with expectant or medical management. Larger trials should be undertaken to critically assess surgical evacuation compared to medical management, factoring in the psychologic impact of treatment. We believe that medical management will prove to be the most appropriate treatment for uncomplicated spontaneous incomplete abortion in the 21st century.

  6. Genetic evidence for the involvement of the S-layer protein gene sap and the sporulation genes spo0A, spo0B, and spo0F in Phage AP50c infection of Bacillus anthracis.

    PubMed

    Plaut, Roger D; Beaber, John W; Zemansky, Jason; Kaur, Ajinder P; George, Matroner; Biswas, Biswajit; Henry, Matthew; Bishop-Lilly, Kimberly A; Mokashi, Vishwesh; Hannah, Ryan M; Pope, Robert K; Read, Timothy D; Stibitz, Scott; Calendar, Richard; Sozhamannan, Shanmuga

    2014-03-01

    In order to better characterize the Bacillus anthracis typing phage AP50c, we designed a genetic screen to identify its bacterial receptor. Insertions of the transposon mariner or targeted deletions of the structural gene for the S-layer protein Sap and the sporulation genes spo0A, spo0B, and spo0F in B. anthracis Sterne resulted in phage resistance with concomitant defects in phage adsorption and infectivity. Electron microscopy of bacteria incubated with AP50c revealed phage particles associated with the surface of bacilli of the Sterne strain but not with the surfaces of Δsap, Δspo0A, Δspo0B, or Δspo0F mutants. The amount of Sap in the S layer of each of the spo0 mutant strains was substantially reduced compared to that of the parent strain, and incubation of AP50c with purified recombinant Sap led to a substantial reduction in phage activity. Phylogenetic analysis based on whole-genome sequences of B. cereus sensu lato strains revealed several closely related B. cereus and B. thuringiensis strains that carry sap genes with very high similarities to the sap gene of B. anthracis. Complementation of the Δsap mutant in trans with the wild-type B. anthracis sap or the sap gene from either of two different B. cereus strains that are sensitive to AP50c infection restored phage sensitivity, and electron microscopy confirmed attachment of phage particles to the surface of each of the complemented strains. Based on these data, we postulate that Sap is involved in AP50c infectivity, most likely acting as the phage receptor, and that the spo0 genes may regulate synthesis of Sap and/or formation of the S layer.

  7. Genetic Evidence for the Involvement of the S-Layer Protein Gene sap and the Sporulation Genes spo0A, spo0B, and spo0F in Phage AP50c Infection of Bacillus anthracis

    PubMed Central

    Beaber, John W.; Zemansky, Jason; Kaur, Ajinder P.; George, Matroner; Biswas, Biswajit; Henry, Matthew; Bishop-Lilly, Kimberly A.; Mokashi, Vishwesh; Hannah, Ryan M.; Pope, Robert K.; Read, Timothy D.; Stibitz, Scott; Calendar, Richard; Sozhamannan, Shanmuga

    2014-01-01

    In order to better characterize the Bacillus anthracis typing phage AP50c, we designed a genetic screen to identify its bacterial receptor. Insertions of the transposon mariner or targeted deletions of the structural gene for the S-layer protein Sap and the sporulation genes spo0A, spo0B, and spo0F in B. anthracis Sterne resulted in phage resistance with concomitant defects in phage adsorption and infectivity. Electron microscopy of bacteria incubated with AP50c revealed phage particles associated with the surface of bacilli of the Sterne strain but not with the surfaces of Δsap, Δspo0A, Δspo0B, or Δspo0F mutants. The amount of Sap in the S layer of each of the spo0 mutant strains was substantially reduced compared to that of the parent strain, and incubation of AP50c with purified recombinant Sap led to a substantial reduction in phage activity. Phylogenetic analysis based on whole-genome sequences of B. cereus sensu lato strains revealed several closely related B. cereus and B. thuringiensis strains that carry sap genes with very high similarities to the sap gene of B. anthracis. Complementation of the Δsap mutant in trans with the wild-type B. anthracis sap or the sap gene from either of two different B. cereus strains that are sensitive to AP50c infection restored phage sensitivity, and electron microscopy confirmed attachment of phage particles to the surface of each of the complemented strains. Based on these data, we postulate that Sap is involved in AP50c infectivity, most likely acting as the phage receptor, and that the spo0 genes may regulate synthesis of Sap and/or formation of the S layer. PMID:24363347

  8. Phage-Phagocyte Interactions and Their Implications for Phage Application as Therapeutics

    PubMed Central

    Jończyk-Matysiak, Ewa; Weber-Dąbrowska, Beata; Owczarek, Barbara; Międzybrodzki, Ryszard; Łusiak-Szelachowska, Marzanna; Łodej, Norbert; Górski, Andrzej

    2017-01-01

    Phagocytes are the main component of innate immunity. They remove pathogens and particles from organisms using their bactericidal tools in the form of both reactive oxygen species and degrading enzymes—contained in granules—that are potentially toxic proteins. Therefore, it is important to investigate the possible interactions between phages and immune cells and avoid any phage side effects on them. Recent progress in knowledge concerning the influence of phages on phagocytes is also important as such interactions may shape the immune response. In this review we have summarized the current knowledge on phage interactions with phagocytes described so far and their potential implications for phage therapy. The data suggesting that phage do not downregulate important phagocyte functions are especially relevant for the concept of phage therapy. PMID:28613272

  9. Characterization and Complete Genome Sequences of Three N4-Like Roseobacter Phages Isolated from the South China Sea.

    PubMed

    Li, Baolian; Zhang, Si; Long, Lijuan; Huang, Sijun

    2016-09-01

    Three bacteriophages (RD-1410W1-01, RD-1410Ws-07, and DS-1410Ws-06) were isolated from the surface water of Sanya Bay, northern South China Sea, on two marine bacteria type strains of the Roseobacter lineage. These phages have an isometric head and a short tail, morphologically belonging to the Podoviridae family. Two of these phages can infect four of seven marine roseobacter strains tested and the other one can infect three of them, showing relatively broader host ranges compared to known N4-like roseophages. One-step growth curves showed that these phages have similar short latent periods (1-2 h) but highly variable burst sizes (27-341 pfu cell(-1)). Their complete genomes show high level of similarities to known N4-like roseophages in terms of genome size, G + C content, gene content, and arrangement. The morphological and genomic features of these phages indicate that they belong to the N4likevirus genus. Moreover, comparative genomic analysis based on 43 N4-like phages (10 roseobacter phages and 33 phages infecting other lineages of bacteria) revealed a core genome of 18 genes shared by all the 43 phages and 38 genes shared by all the ten roseophages. The 38 core genes of N4-like roseophages nearly make up 70 % of each genome in length. Phylogenetic analysis based on the concatenated core gene products showed that our phage isolates represent two new phyletic branches, suggesting the broad genetic diversity of marine N4-like roseophages remains.

  10. Evolution of parasitism and mutualism between filamentous phage M13 and Escherichia coli.

    PubMed

    Shapiro, Jason W; Williams, Elizabeth S C P; Turner, Paul E

    2016-01-01

    Background. How host-symbiont interactions coevolve between mutualism and parasitism depends on the ecology of the system and on the genetic and physiological constraints of the organisms involved. Theory often predicts that greater reliance on horizontal transmission favors increased costs of infection and may result in more virulent parasites or less beneficial mutualists. We set out to understand transitions between parasitism and mutualism by evolving the filamentous bacteriophage M13 and its host Escherichia coli. Results. The effect of phage M13 on bacterial fitness depends on the growth environment, and initial assays revealed that infected bacteria reproduce faster and to higher density than uninfected bacteria in 96-well microplates. These data suggested that M13 is, in fact, a facultative mutualist of E. coli. We then allowed E. coli and M13 to evolve in replicated environments, which varied in the relative opportunity for horizontal and vertical transmission of phage in order to assess the evolutionary stability of this mutualism. After 20 experimental passages, infected bacteria from treatments with both vertical and horizontal transmission of phage had evolved the fastest growth rates. At the same time, phage from these treatments no longer benefited the ancestral bacteria. Conclusions. These data suggest a positive correlation between the positive effects of M13 on E. coli hosts from the same culture and the negative effects of the same phage toward the ancestral bacterial genotype. The results also expose flaws in applying concepts from the virulence-transmission tradeoff hypothesis to mutualism evolution. We discuss the data in the context of more recent theory on how horizontal transmission affects mutualisms and explore how these effects influence phages encoding virulence factors in pathogenic bacteria.

  11. Genetically Engineered Phages: a Review of Advances over the Last Decade

    PubMed Central

    Pires, Diana P.; Sillankorva, Sanna; Azeredo, Joana

    2016-01-01

    SUMMARY Soon after their discovery in the early 20th century, bacteriophages were recognized to have great potential as antimicrobial agents, a potential that has yet to be fully realized. The nascent field of phage therapy was adversely affected by inadequately controlled trials and the discovery of antibiotics. Although the study of phages as anti-infective agents slowed, phages played an important role in the development of molecular biology. In recent years, the increase in multidrug-resistant bacteria has renewed interest in the use of phages as antimicrobial agents. With the wide array of possibilities offered by genetic engineering, these bacterial viruses are being modified to precisely control and detect bacteria and to serve as new sources of antibacterials. In applications that go beyond their antimicrobial activity, phages are also being developed as vehicles for drug delivery and vaccines, as well as for the assembly of new materials. This review highlights advances in techniques used to engineer phages for all of these purposes and discusses existing challenges and opportunities for future work. PMID:27250768

  12. Immunohistochemical Identification and Pathologic Findings in Natural Cases of Equine Abortion Caused by Leptospiral Infection

    PubMed Central

    Szeredi, L.; Haake, D. A.

    2009-01-01

    The aim of this study was to examine the utility of immunohistochemistry (IHC) in the diagnosis of leptospiral equine abortion and to compare IHC to silver staining and serology of the aborted mares. Ninety-six fetuses from 57 farms were examined using all 3 diagnostic techniques, revealing evidence of leptospiral infection in 3 fetuses (3.1%) from 3 (5.3%) different farms. A new finding in 1 of these confirmed cases of leptospiral abortion was the presence of macroscopic pinpoint grayish-white nodules that had a histologic correlate of hepatic necrosis; other histologic findings were consistent with those previously reported. IHC performed using 2 different leptospiral antisera (multivalent whole-cell rabbit antiserum and rabbit antiserum against the major outer membrane protein LipL32) yielded similar results. IHC was more sensitive (19/21 [90.5%] tissue samples) than silver staining (8/21 [38.1%] tissue samples), and more specific than serology performed using the microscopic agglutination test. The primary advantage of IHC over silver staining was the ability of IHC to identify leptospiral antigen not only as morphologically intact spiral forms. PMID:16966455

  13. Preparation of RNA from bacteria infected with bacteriophages: a case study from the marine unicellular Synechococcus sp. WH7803 infected by phage S-PM2.

    PubMed

    Shan, Jinyu; Clokie, Martha

    2009-01-01

    Bacteriophages manipulate bacterial gene expression in order to express their own genes or influence bacterial metabolism. Gene expression can be studied using real-time PCR or microarrays. Either technique requires the prior isolation of high quality RNA uncontaminated by the presence of genomic DNA. We outline the considerations necessary when working with bacteriophage infected bacterial cells. We also give an example of a protocol for extraction and quantification of high quality RNA from infected bacterial cells, using the marine cyanobacterium WH7803 and the phage S-PM2 as a case study. This protocol can be modified to extract RNA from the host/bacteriophage of interest.

  14. The action of Escherichia coli CRISPR-Cas system on lytic bacteriophages with different lifestyles and development strategies.

    PubMed

    Strotskaya, Alexandra; Savitskaya, Ekaterina; Metlitskaya, Anastasia; Morozova, Natalia; Datsenko, Kirill A; Semenova, Ekaterina; Severinov, Konstantin

    2017-02-28

    CRISPR-Cas systems provide prokaryotes with adaptive defense against bacteriophage infections. Given an enormous variety of strategies used by phages to overcome their hosts, one can expect that the efficiency of protective action of CRISPR-Cas systems against different viruses should vary. Here, we created a collection of Escherichia coli strains with type I-E CRISPR-Cas system targeting various positions in the genomes of bacteriophages λ, T5, T7, T4 and R1-37 and investigated the ability of these strains to resist the infection and acquire additional CRISPR spacers from the infecting phage. We find that the efficiency of CRISPR-Cas targeting by the host is determined by phage life style, the positions of the targeted protospacer within the genome, and the state of phage DNA. The results also suggest that during infection by lytic phages that are susceptible to CRISPR interference, CRISPR-Cas does not act as a true immunity system that saves the infected cell but rather enforces an abortive infection pathway leading to infected cell death with no phage progeny release. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Genomic, proteomic and bioinformatic analysis of two temperate phages in Roseobacter clade bacteria isolated from the deep-sea water.

    PubMed

    Tang, Kai; Lin, Dan; Zheng, Qiang; Liu, Keshao; Yang, Yujie; Han, Yu; Jiao, Nianzhi

    2017-06-27

    Marine phages are spectacularly diverse in nature. Dozens of roseophages infecting members of Roseobacter clade bacteria were isolated and characterized, exhibiting a very high degree of genetic diversity. In the present study, the induction of two temperate bacteriophages, namely, vB_ThpS-P1 and vB_PeaS-P1, was performed in Roseobacter clade bacteria isolated from the deep-sea water, Thiobacimonas profunda JLT2016 and Pelagibaca abyssi JLT2014, respectively. Two novel phages in morphological, genomic and proteomic features were presented, and their phylogeny and evolutionary relationships were explored by bioinformatic analysis. Electron microscopy showed that the morphology of the two phages were similar to that of siphoviruses. Genome sequencing indicated that the two phages were similar in size, organization, and content, thereby suggesting that these shared a common ancestor. Despite the presence of Mu-like phage head genes, the phages are more closely related to Rhodobacter phage RC1 than Mu phages in terms of gene content and sequence similarity. Based on comparative genomic and phylogenetic analysis, we propose a Mu-like head phage group to allow for the inclusion of Mu-like phages and two newly phages. The sequences of the Mu-like head phage group were widespread, occurring in each investigated metagenomes. Furthermore, the horizontal exchange of genetic material within the Mu-like head phage group might have involved a gene that was associated with phage phenotypic characteristics. This study is the first report on the complete genome sequences of temperate phages that infect deep-sea roseobacters, belonging to the Mu-like head phage group. The Mu-like head phage group might represent a small but ubiquitous fraction of marine viral diversity.

  16. A case of Candida guilliermondii abortion in an Arab mare

    PubMed Central

    Stefanetti, Valentina; Marenzoni, Maria Luisa; Lepri, Elvio; Coletti, Mauro; Casagrande Proietti, Patrizia; Agnetti, Francesco; Crotti, Silvia; Pitzurra, Lucia; Del Sero, Andrea; Passamonti, Fabrizio

    2014-01-01

    Ascending infections of equine uterus frequently result in placentitis and abortions; most of these infections are bacterial and are less commonly due to fungi. This report describes an abortion case in an Arab mare due to Candida guilliermondii that was diagnosed via cytological, histological, cultural and biomolecular assays. The histological lesions found were severe necrotizing placentitis associated with fetal pneumonia. To our knowledge this is the first case of C. guilliermondii abortion reported in equine species. PMID:24707460

  17. Phage survival: the biodegradability of M13 phage display library in vitro.

    PubMed

    Tóthová, L'ubomíra; Bábíčková, Janka; Celec, Peter

    2012-01-01

    Administration of bacteriophages is used for phage therapy modulation of gut microbiome or for in vivo phage display. The aim of the study was to analyze the survival of M13 phage in different body fluids and tissues in vitro. The survival of M13 phage was measured in vitro in human blood, saliva, urine, artificial gastric juice (AGJ), and mouse homogenates of stomach, jejunum, and colon after defined time points (5, 15, or 45 Min). The plates were inspected after overnight incubation and the plaques were counted. No phage was recovered after 5 Min of incubation with AGJ. In urine, the phage survival was decreased by 44% after 5 Min of incubation (P = 0.004). In saliva, the recovered titer was decreased by 33% and 88% (P < 0.05) after 15 and 45 Min, respectively. Phage coincubation with jejunum homogenate led to significant decrease of phage titer by 72% (P < 0.01) after 15 Min and by 99% (P < 0.001) after 45 Min. Decreased survival of M13 phage depending on time of incubation was proved under several in vitro conditions, with low pH in the AGJ having the most detrimental effect on phage survival. Phage pharmacokinetics described in vitro might have applications for the use of bacteriophages in vivo. © 2012 International Union of Biochemistry and Molecular Biology, Inc.

  18. Polar flagella rotation in Vibrio parahaemolyticus confers resistance to bacteriophage infection

    PubMed Central

    Zhang, Hui; Li, Lu; Zhao, Zhe; Peng, Daxin; Zhou, Xiaohui

    2016-01-01

    Bacteriophage has been recognized as a novel approach to treat bacterial infectious diseases. However, phage resistance may reduce the efficacy of phage therapy. Here, we described a mechanism of bacterial resistance to phage infections. In Gram-negative enteric pathogen Vibrio parahaemolyticus, we found that polar flagella can reduce the phage infectivity. Deletion of polar flagella, but not the lateral flagella, can dramatically promote the adsorption of phage to the bacteria and enhances the phage infectivity to V. parahaemolyticus, indicating that polar flagella play an inhibitory role in the phage infection. Notably, it is the rotation, not the physical presence, of polar flagella that inhibits the phage infection of V. parahaemolyticus. Strikingly, phage dramatically reduces the virulence of V. parahaemolyticus only when polar flagella were absent both in vitro and in vivo. These results indicated that polar flagella rotation is a previously unidentified mechanism that confers bacteriophage resistance. PMID:27189325

  19. Liposome-Encapsulated Bacteriophages for Enhanced Oral Phage Therapy against Salmonella spp.

    PubMed Central

    Colom, Joan; Cano-Sarabia, Mary; Otero, Jennifer; Cortés, Pilar

    2015-01-01

    Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units. The liposome coating also improved the retention of bacteriophages in the chicken intestinal tract. When cocktails of the encapsulated and nonencapsulated phages were administered to broilers, after 72 h the encapsulated phages were detected in 38.1% of the animals, whereas the nonencapsulated phages were present in only 9.5%. The difference was significant. In addition, in an in vitro experiment, the cecal contents of broilers promoted the release of the phages from the liposomes. In broilers experimentally infected with Salmonella, the daily administration of the two cocktails for 6 days postinfection conferred similar levels of protection against Salmonella colonization. However, once treatment was stopped, protection by the nonencapsulated phages disappeared, whereas that provided by the encapsulated phages persisted for at least 1 week, showing the enhanced efficacy of the encapsulated phages in protecting poultry against Salmonella over time. The methodology described here allows the liposome encapsulation of phages of different morphologies. The preparations can be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals. PMID:25956778

  20. The Novel Phages phiCD5763 and phiCD2955 Represent Two Groups of Big Plasmidial Siphoviridae Phages of Clostridium difficile.

    PubMed

    Ramírez-Vargas, Gabriel; Goh, Shan; Rodríguez, César

    2018-01-01

    Until recently, Clostridium difficile phages were limited to Myoviruses and Siphoviruses of medium genome length (32-57 kb). Here we report the finding of phiCD5763, a Siphovirus with a large extrachromosomal circular genome (132.5 kb, 172 ORFs) and a large capsid (205.6 ± 25.6 nm in diameter) infecting MLST Clade 1 strains of C. difficile . Two subgroups of big phage genomes similar to phiCD5763 were identified in 32 NAP CR1 /RT012/ST-54 C. difficile isolates from Costa Rica and in whole genome sequences (WGS) of 41 C. difficile isolates of Clades 1, 2, 3, and 4 from Canada, USA, UK, Belgium, Iraq, and China. Through comparative genomics we discovered another putative big phage genome in a non-NAP CR1 isolate from Costa Rica, phiCD2955, which represents other big phage genomes found in 130 WGS of MLST Clade 1 and 2 isolates from Canada, USA, Hungary, France, Austria, and UK. phiCD2955 (131.6 kb, 172 ORFs) is related to a previously reported C. difficile phage genome, phiCD211/phiCDIF1296T. Detailed genome analyses of phiCD5763, phiCD2955, phiCD211/phiCDIF1296T, and seven other putative C. difficile big phage genome sequences of 131-136 kb reconstructed from publicly available WGS revealed a modular gene organization and high levels of sequence heterogeneity at several hotspots, suggesting that these genomes correspond to biological entities undergoing recombination. Compared to other C. difficile phages, these big phages have unique predicted terminase, capsid, portal, neck and tail proteins, receptor binding proteins (RBPs), recombinases, resolvases, primases, helicases, ligases, and hypothetical proteins. Moreover, their predicted gene load suggests a complex regulation of both phage and host functions. Overall, our results indicate that the prevalence of C. difficile big bacteriophages is more widespread than realized and open new avenues of research aiming to decipher how these viral elements influence the biology of this emerging pathogen.

  1. International developments in abortion laws: 1977-88.

    PubMed Central

    Cook, R J; Dickens, B M

    1988-01-01

    During the period between 1977 and the first quarter of 1988, 35 countries liberalized their abortion laws and four countries limited grounds for the procedure. Most legislation has extended abortion eligibility through traditional indications such as danger to maternal health or fetal handicap, but a number of other indications have been created such as adolescence, advanced maternal age, family circumstances, and AIDS or HIV infection. A number of countries have redesigned their abortion laws as part of a comprehensive package to facilitate access to and delivery of contraception, voluntary sterilization, and abortion services. Abortion litigation has increased and stimulated the liberalization of abortion provisions and the support of women's autonomous choice within the law. In Canada, the entire criminal prohibition of abortion was held unconstitutional for violating women's integrity and security. In contrast, Latin American and other constitutional developments may limit legal abortion to instances of danger to women's lives. PMID:3048126

  2. Characterization and Genomic Study of Phage vB_EcoS-B2 Infecting Multidrug-Resistant Escherichia coli

    PubMed Central

    Xu, Yue; Yu, Xinyan; Gu, Yu; Huang, Xu; Liu, Genyan; Liu, Xiaoqiu

    2018-01-01

    The potential of bacteriophage as an alternative antibacterial agent has been reconsidered for control of pathogenic bacteria due to the widespread occurrence of multi-drug resistance bacteria. More and more lytic phages have been isolated recently. In the present study, we isolated a lytic phage named vB_EcoS-B2 from waste water. VB_EcoS-B2 has an icosahedral symmetry head and a long tail without a contractile sheath, indicating that it belongs to the family Siphoviridae. The complete genome of vB_EcoS-B2 is composed of a circular double stranded DNA of 44,283 bp in length, with 54.77% GC content. vB_EcoS-B2 is homologous to 14 relative phages (such as Escherichia phage SSL-2009a, Escherichia phage JL1, and Shigella phage EP23), but most of these phages exhibit different gene arrangement. Our results serve to extend our understanding toward phage evolution of family Siphoviridae of coliphages. Sixty-five putative open reading frames were predicted in the complete genome of vB_EcoS-B2. Twenty-one of proteins encoded by vB_EcoS-B2 were determined in phage particles by Mass Spectrometry. Bacteriophage genome and proteome analysis confirmed the lytic nature of vB_EcoS-B2, namely, the absence of toxin-coding genes, islands of pathogenicity, or genes through lysogeny or transduction. Furthermore, vB_EcoS-B2 significantly reduced the growth of E. coli MG1655 and also inhibited the growth of several multi-drug resistant clinical stains of E. coli. Phage vB_EcoS-B2 can kill some of the MRD E. coli entirely, strongly indicating us that it could be one of the components of phage cocktails to treat multi-drug resistant E. coli. This phage could be used to interrupt or reduce the spread of multi-drug resistant E. coli. PMID:29780362

  3. Evolution of parasitism and mutualism between filamentous phage M13 and Escherichia coli

    PubMed Central

    Williams, Elizabeth S.C.P.; Turner, Paul E.

    2016-01-01

    Background. How host-symbiont interactions coevolve between mutualism and parasitism depends on the ecology of the system and on the genetic and physiological constraints of the organisms involved. Theory often predicts that greater reliance on horizontal transmission favors increased costs of infection and may result in more virulent parasites or less beneficial mutualists. We set out to understand transitions between parasitism and mutualism by evolving the filamentous bacteriophage M13 and its host Escherichia coli. Results. The effect of phage M13 on bacterial fitness depends on the growth environment, and initial assays revealed that infected bacteria reproduce faster and to higher density than uninfected bacteria in 96-well microplates. These data suggested that M13 is, in fact, a facultative mutualist of E. coli. We then allowed E. coli and M13 to evolve in replicated environments, which varied in the relative opportunity for horizontal and vertical transmission of phage in order to assess the evolutionary stability of this mutualism. After 20 experimental passages, infected bacteria from treatments with both vertical and horizontal transmission of phage had evolved the fastest growth rates. At the same time, phage from these treatments no longer benefited the ancestral bacteria. Conclusions. These data suggest a positive correlation between the positive effects of M13 on E. coli hosts from the same culture and the negative effects of the same phage toward the ancestral bacterial genotype. The results also expose flaws in applying concepts from the virulence-transmission tradeoff hypothesis to mutualism evolution. We discuss the data in the context of more recent theory on how horizontal transmission affects mutualisms and explore how these effects influence phages encoding virulence factors in pathogenic bacteria. PMID:27257543

  4. A simple and rapid method to isolate purer M13 phage by isoelectric precipitation.

    PubMed

    Dong, Dexian; Sutaria, Sanjana; Hwangbo, Je Yeol; Chen, P

    2013-09-01

    M13 virus (phage) has been extensively used in phage display technology and nanomaterial templating. Our research aimed to use M13 phage to template sulfur nanoparticles for making lithium ion batteries. Traditional methods for harvesting M13 phage from Escherichia coli employ polyethylene glycol (PEG)-based precipitation, and the yield is usually measured by plaque counting. With this method, PEG residue is present in the M13 phage pellet and is difficult to eliminate. To resolve this issue, a method based on isoelectric precipitation was introduced and tested. The isoelectric method resulted in the production of purer phage with a higher yield, compared to the traditional PEG-based method. There is no significant variation in infectivity of the phage prepared using isoelectric precipitation, and the dynamic light scattering data indirectly prove that the phage structure is not damaged by pH adjustment. To maximize phage production, a dry-weight yield curve of M13 phage for various culture times was produced. The yield curve is proportional to the growth curve of E. coli. On a 200-mL culture scale, 0.2 g L(-1) M13 phage (dry-weight) was produced by the isoelectric precipitation method.

  5. Is phage therapy acceptable in the immunocompromised host?

    PubMed

    Borysowski, Jan; Górski, Andrzej

    2008-09-01

    Over the last decade, bacteriophages (bacterial viruses) have emerged as the major alternative to antibiotics in the treatment of antibiotic-resistant infections. While a considerable body of evidence has accumulated for the efficacy and safety of phage therapy in immunocompetent patients, data remain relatively scarce regarding its use in the immunocompromised host. To our knowledge, the present article is the first to summarize all findings, of both experimental and clinical studies, that may be relevant to the employment of phage therapy in immunocompromised patients. The available data suggest that bacteriophages could also be an efficacious and safe therapeutic modality in such patients.

  6. The temperate Burkholderia phage AP3 of the Peduovirinae shows efficient antimicrobial activity against B. cenocepacia of the IIIA lineage.

    PubMed

    Roszniowski, Bartosz; Latka, Agnieszka; Maciejewska, Barbara; Vandenheuvel, Dieter; Olszak, Tomasz; Briers, Yves; Holt, Giles S; Valvano, Miguel A; Lavigne, Rob; Smith, Darren L; Drulis-Kawa, Zuzanna

    2017-02-01

    Burkholderia phage AP3 (vB_BceM_AP3) is a temperate virus of the Myoviridae and the Peduovirinae subfamily (P2likevirus genus). This phage specifically infects multidrug-resistant clinical Burkholderia cenocepacia lineage IIIA strains commonly isolated from cystic fibrosis patients. AP3 exhibits high pairwise nucleotide identity (61.7 %) to Burkholderia phage KS5, specific to the same B. cenocepacia host, and has 46.7-49.5 % identity to phages infecting other species of Burkholderia. The lysis cassette of these related phages has a similar organization (putative antiholin, putative holin, endolysin, and spanins) and shows 29-98 % homology between specific lysis genes, in contrast to Enterobacteria phage P2, the hallmark phage of this genus. The AP3 and KS5 lysis genes have conserved locations and high amino acid sequence similarity. The AP3 bacteriophage particles remain infective up to 5 h at pH 4-10 and are stable at 60 °C for 30 min, but are sensitive to chloroform, with no remaining infective particles after 24 h of treatment. AP3 lysogeny can occur by stable genomic integration and by pseudo-lysogeny. The lysogenic bacterial mutants did not exhibit any significant changes in virulence compared to wild-type host strain when tested in the Galleria mellonella moth wax model. Moreover, AP3 treatment of larvae infected with B. cenocepacia revealed a significant increase (P < 0.0001) in larvae survival in comparison to AP3-untreated infected larvae. AP3 showed robust lytic activity, as evidenced by its broad host range, the absence of increased virulence in lysogenic isolates, the lack of bacterial gene disruption conditioned by bacterial tRNA downstream integration site, and the absence of detected toxin sequences. These data suggest that the AP3 phage is a promising potent agent against bacteria belonging to the most common B. cenocepacia IIIA lineage strains.

  7. Intra-domain phage display (ID-PhD) of peptides and protein mini-domains censored from canonical pIII phage display.

    PubMed

    Tjhung, Katrina F; Deiss, Frédérique; Tran, Jessica; Chou, Ying; Derda, Ratmir

    2015-01-01

    In this paper, we describe multivalent display of peptide and protein sequences typically censored from traditional N-terminal display on protein pIII of filamentous bacteriophage M13. Using site-directed mutagenesis of commercially available M13KE phage cloning vector, we introduced sites that permit efficient cloning using restriction enzymes between domains N1 and N2 of the pIII protein. As infectivity of phage is directly linked to the integrity of the connection between N1 and N2 domains, intra-domain phage display (ID-PhD) allows for simple quality control of the display and the natural variations in the displayed sequences. Additionally, direct linkage to phage propagation allows efficient monitoring of sequence cleavage, providing a convenient system for selection and evolution of protease-susceptible or protease-resistant sequences. As an example of the benefits of such an ID-PhD system, we displayed a negatively charged FLAG sequence, which is known to be post-translationally excised from pIII when displayed on the N-terminus, as well as positively charged sequences which suppress production of phage when displayed on the N-terminus. ID-PhD of FLAG exhibited sub-nanomolar apparent Kd suggesting multivalent nature of the display. A TEV-protease recognition sequence (TEVrs) co-expressed in tandem with FLAG, allowed us to demonstrate that 99.9997% of the phage displayed the FLAG-TEVrs tandem and can be recognized and cleaved by TEV-protease. The residual 0.0003% consisted of phage clones that have excised the insert from their genome. ID-PhD is also amenable to display of protein mini-domains, such as the 33-residue minimized Z-domain of protein A. We show that it is thus possible to use ID-PhD for multivalent display and selection of mini-domain proteins (Affibodies, scFv, etc.).

  8. Prospects of Phage Application in the Treatment of Acne Caused by Propionibacterium acnes

    PubMed Central

    Jończyk-Matysiak, Ewa; Weber-Dąbrowska, Beata; Żaczek, Maciej; Międzybrodzki, Ryszard; Letkiewicz, Sławomir; Łusiak-Szelchowska, Marzanna; Górski, Andrzej

    2017-01-01

    Propionibacterium acnes is associated with purulent skin infections, and it poses a global problem for both patients and doctors. Acne vulgaris (acne) remains a problem due to its chronic character and difficulty of treatment, as well as its large impact on patients' quality of life. Due to the chronic course of the disease, treatment is long lasting, and often ineffective. Currently there are data regarding isolation of P. acnes phages, and there have been numerous studies on phage killing of P. acnes, but no data are available on phage application specifically in acne treatment. In this review, we have summarized the current knowledge on the phages active against P. acnes described so far and their potential application in the treatment of acne associated with P. acnes. The treatment of acne with phages may be important in order to reduce the overuse of antibiotics, which are currently the main acne treatment. However, more detailed studies are first needed to understand phage functioning in the skin microbiome and the possibility to use phages to combat P. acnes. PMID:28228751

  9. Reversing Bacterial Resistance to Antibiotics by Phage-Mediated Delivery of Dominant Sensitive Genes

    PubMed Central

    Edgar, Rotem; Friedman, Nir; Molshanski-Mor, Shahar

    2012-01-01

    Pathogen resistance to antibiotics is a rapidly growing problem, leading to an urgent need for novel antimicrobial agents. Unfortunately, development of new antibiotics faces numerous obstacles, and a method that resensitizes pathogens to approved antibiotics therefore holds key advantages. We present a proof of principle for a system that restores antibiotic efficiency by reversing pathogen resistance. This system uses temperate phages to introduce, by lysogenization, the genes rpsL and gyrA conferring sensitivity in a dominant fashion to two antibiotics, streptomycin and nalidixic acid, respectively. Unique selective pressure is generated to enrich for bacteria that harbor the phages carrying the sensitizing constructs. This selection pressure is based on a toxic compound, tellurite, and therefore does not forfeit any antibiotic for the sensitization procedure. We further demonstrate a possible way of reducing undesirable recombination events by synthesizing dominant sensitive genes with major barriers to homologous recombination. Such synthesis does not significantly reduce the gene's sensitization ability. Unlike conventional bacteriophage therapy, the system does not rely on the phage's ability to kill pathogens in the infected host, but instead, on its ability to deliver genetic constructs into the bacteria and thus render them sensitive to antibiotics prior to host infection. We believe that transfer of the sensitizing cassette by the constructed phage will significantly enrich for antibiotic-treatable pathogens on hospital surfaces. Broad usage of the proposed system, in contrast to antibiotics and phage therapy, will potentially change the nature of nosocomial infections toward being more susceptible to antibiotics rather than more resistant. PMID:22113912

  10. Reversing bacterial resistance to antibiotics by phage-mediated delivery of dominant sensitive genes.

    PubMed

    Edgar, Rotem; Friedman, Nir; Molshanski-Mor, Shahar; Qimron, Udi

    2012-02-01

    Pathogen resistance to antibiotics is a rapidly growing problem, leading to an urgent need for novel antimicrobial agents. Unfortunately, development of new antibiotics faces numerous obstacles, and a method that resensitizes pathogens to approved antibiotics therefore holds key advantages. We present a proof of principle for a system that restores antibiotic efficiency by reversing pathogen resistance. This system uses temperate phages to introduce, by lysogenization, the genes rpsL and gyrA conferring sensitivity in a dominant fashion to two antibiotics, streptomycin and nalidixic acid, respectively. Unique selective pressure is generated to enrich for bacteria that harbor the phages carrying the sensitizing constructs. This selection pressure is based on a toxic compound, tellurite, and therefore does not forfeit any antibiotic for the sensitization procedure. We further demonstrate a possible way of reducing undesirable recombination events by synthesizing dominant sensitive genes with major barriers to homologous recombination. Such synthesis does not significantly reduce the gene's sensitization ability. Unlike conventional bacteriophage therapy, the system does not rely on the phage's ability to kill pathogens in the infected host, but instead, on its ability to deliver genetic constructs into the bacteria and thus render them sensitive to antibiotics prior to host infection. We believe that transfer of the sensitizing cassette by the constructed phage will significantly enrich for antibiotic-treatable pathogens on hospital surfaces. Broad usage of the proposed system, in contrast to antibiotics and phage therapy, will potentially change the nature of nosocomial infections toward being more susceptible to antibiotics rather than more resistant.

  11. From Bits and Pieces to Whole Phage to Nanomachines: Pathogen Detection Using Bacteriophages.

    PubMed

    Anany, H; Chou, Y; Cucic, S; Derda, R; Evoy, S; Griffiths, M W

    2017-02-28

    The innate specificity of bacteriophages toward their hosts makes them excellent candidates for the development of detection assays. They can be used in many ways to detect pathogens, and each has its own advantages and disadvantages. Whole bacteriophages can carry reporter genes to alter the phenotype of the target. Bacteriophages can act as staining agents or the progeny of the infection process can be detected, which further increases the sensitivity of the detection assay. Compared with whole-phage particles, use of phage components as probes offers other advantages: for example, smaller probe size to enhance binding activity, phage structures that can be engineered for better affinity, as well as specificity, binding properties, and robustness. When no natural binding with the target exists, phages can be used as vehicles to identify new protein-ligand interactions necessary for diagnostics. This review comprehensively summarizes many uses of phages as detection tools and points the way toward how phage-based technologies may be improved.

  12. The T7-related Pseudomonas putida phage φ15 displays virion-associated biofilm degradation properties.

    PubMed

    Cornelissen, Anneleen; Ceyssens, Pieter-Jan; T'Syen, Jeroen; Van Praet, Helena; Noben, Jean-Paul; Shaburova, Olga V; Krylov, Victor N; Volckaert, Guido; Lavigne, Rob

    2011-04-19

    Formation of a protected biofilm environment is recognized as one of the major causes of the increasing antibiotic resistance development and emphasizes the need to develop alternative antibacterial strategies, like phage therapy. This study investigates the in vitro degradation of single-species Pseudomonas putida biofilms, PpG1 and RD5PR2, by the novel phage ϕ15, a 'T7-like virus' with a virion-associated exopolysaccharide (EPS) depolymerase. Phage ϕ15 forms plaques surrounded by growing opaque halo zones, indicative for EPS degradation, on seven out of 53 P. putida strains. The absence of haloes on infection resistant strains suggests that the EPS probably act as a primary bacterial receptor for phage infection. Independent of bacterial strain or biofilm age, a time and dose dependent response of ϕ15-mediated biofilm degradation was observed with generally a maximum biofilm degradation 8 h after addition of the higher phage doses (10(4) and 10(6) pfu) and resistance development after 24 h. Biofilm age, an in vivo very variable parameter, reduced markedly phage-mediated degradation of PpG1 biofilms, while degradation of RD5PR2 biofilms and ϕ15 amplification were unaffected. Killing of the planktonic culture occurred in parallel with but was always more pronounced than biofilm degradation, accentuating the need for evaluating phages for therapeutic purposes in biofilm conditions. EPS degrading activity of recombinantly expressed viral tail spike was confirmed by capsule staining. These data suggests that the addition of high initial titers of specifically selected phages with a proper EPS depolymerase are crucial criteria in the development of phage therapy.

  13. Sequencing, genome analysis and host range of a novel Ralstonia phage RsoP1EGY isolated from Egypt

    USDA-ARS?s Scientific Manuscript database

    A novel Ralstonia phage was isolated from soil in Egypt and designated RsPod1SoilEGY using our new four-part phage identifier naming system. When tested, this phage selectively infected only race 3 biovar 2 phylotype IIB sequevar 1, and not non-race 3 biovar 2 strains of Ralstonia solanacearum. The ...

  14. Isolation of a Novel Phage with Activity against Streptococcus mutans Biofilms

    PubMed Central

    Dalmasso, Marion; de Haas, Eric; Neve, Horst; Strain, Ronan; Cousin, Fabien J.; Stockdale, Stephen R.; Ross, R. Paul; Hill, Colin

    2015-01-01

    Streptococcus mutans is one of the principal agents of caries formation mainly, because of its ability to form biofilms at the tooth surface. Bacteriophages (phages) are promising antimicrobial agents that could be used to prevent or treat caries formation by S. mutans. The aim of this study was to isolate new S. mutans phages and to characterize their antimicrobial properties. A new phage, ɸAPCM01, was isolated from a human saliva sample. Its genome was closely related to the only two other available S. mutans phage genomes, M102 and M102AD. ɸAPCM01 inhibited the growth of S. mutans strain DPC6143 within hours in broth and in artificial saliva at multiplicity of infections as low as 2.5x10-5. In the presence of phage ɸAPCM01 the metabolic activity of a S. mutans biofilm was reduced after 24 h of contact and did not increased again after 48 h, and the live cells in the biofilm decreased by at least 5 log cfu/ml. Despite its narrow host range, this newly isolated S. mutans phage exhibits promising antimicrobial properties. PMID:26398909

  15. Immunodiagnosis of Canine Visceral Leishmaniasis Using Mimotope Peptides Selected from Phage Displayed Combinatorial Libraries

    PubMed Central

    Toledo-Machado, Christina Monerat; Machado de Avila, Ricardo Andrez; NGuyen, Christophe; Granier, Claude; Bueno, Lilian Lacerda; Carneiro, Claudia Martins; Menezes-Souza, Daniel; Carneiro, Rubens Antonio; Chávez-Olórtegui, Carlos; Fujiwara, Ricardo Toshio

    2015-01-01

    ELISA and RIFI are currently used for serodiagnosis of canine visceral leishmaniasis (CVL). The accuracy of these tests is controversial in endemic areas where canine infections by Trypanosoma cruzi may occur. We evaluated the usefulness of synthetic peptides that were selected through phage display technique in the serodiagnosis of CVL. Peptides were chosen based on their ability to bind to IgGs purified from infected dogs pooled sera. We selected three phage clones that reacted only with those IgGs. Peptides were synthesized, polymerized with glutaraldehyde, and used as antigens in ELISA assays. Each individual peptide or a mix of them was reactive with infected dogs serum. The assay was highly sensitive and specific when compared to soluble Leishmania antigen that showed cross-reactivity with anti-T. cruzi IgGs. Our results demonstrate that phage display technique is useful for selection of peptides that may represent valuable synthetic antigens for an improved serodiagnosis of CVL. PMID:25710003

  16. The Magistral Phage

    PubMed Central

    Pirnay, Jean-Paul; Verbeken, Gilbert; Ceyssens, Pieter-Jan; Huys, Isabelle; De Vos, Daniel; Ameloot, Charlotte; Fauconnier, Alan

    2018-01-01

    Since time immemorial, phages—the viral parasites of bacteria—have been protecting Earth’s biosphere against bacterial overgrowth. Today, phages could help address the antibiotic resistance crisis that affects all of society. The greatest hurdle to the introduction of phage therapy in Western medicine is the lack of an appropriate legal and regulatory framework. Belgium is now implementing a pragmatic phage therapy framework that centers on the magistral preparation (compounding pharmacy in the US) of tailor-made phage medicines. PMID:29415431

  17. Phage therapy.

    PubMed

    Housby, John N; Mann, Nicholas H

    2009-06-01

    There is a renaissance of interest in the antimicrobial potential of phages as more pathogens become multiply antibiotic resistant. Phage therapy is not a new concept, and it is important to ask why it is not part of the current repertoire of western medicine despite the fact that it has been continuously and extensively used in Eastern Europe for almost a century. Answering this question successfully will, largely, determine whether phage therapy can gain the credibility needed to overcome the scientific, financial and regulatory hurdles facing its adoption in mainstream clinical practice. Despite a paucity of such information from human studies, pharmacokinetic data and clinical outcomes from animal studies are currently providing convincing evidence for the safety and efficacy of phage therapy.

  18. Immune response in bovine neosporosis: Protection or contribution to the pathogenesis of abortion.

    PubMed

    Almería, Sonia; Serrano-Pérez, Beatriz; López-Gatius, Fernando

    2017-08-01

    Neospora caninum is a protozoan parasite with a preference for cattle and dogs as hosts. When N. caninum infection occurs in cattle it induces abortion, bovine neosporosis being a main cause of abortion worldwide. In dairy cattle, the economic burden of neosporosis-associated abortion is so great that it might results in closure of a farm. However, not all infected cows abort and it is not yet understood why this occurs. At present there is no effective treatment or vaccine. This review provides insights on how immune response against the parasite determines protection or contribution to abortion. Aspects on markers of risk of abortion are also discussed. Humoral immune responses are not protective against N. caninum but seropositivity and antibody level can be good markers for a diagnosis of bovine neosporosis and its associated abortion risk. In addition, humoral mechanisms against N. caninum infection and abortion differ in pure-breed and cross-breed pregnant dairy and beef cattle. Concentrations of Pregnancy Associated glycoprotein -2 (PAG-2) can also be used to predict abortion. A partially protective immune response encompasses increased IFN-γ expression, which has to be counterbalanced by other cytokines such as IL-12 and IL-10, especially towards the end of pregnancy. Although IFN-γ is required to limit parasite proliferation a critical threshold of the IFN-γ response is also required to limit adverse effects on pregnancy. In clinical terms, it may be stated that IFN-γ production and cross-breed pregnancy can protect Neospora-infected dairy cows against abortion. Published by Elsevier Ltd.

  19. ORFeome Phage Display.

    PubMed

    Zantow, Jonas; Moreira, Gustavo Marçal Schmidt Garcia; Dübel, Stefan; Hust, Michael

    2018-01-01

    ORFeome phage display allows the efficient functional screening of entire proteomes or even metaproteomes to identify immunogenic proteins. For this purpose, randomly fragmented, whole genomes or metagenomes are cloned into a phage-display vector allowing positive selection for open reading frames (ORF) to improve the library quality. These libraries display all possible proteins encoded by a pathogen or a microbiome on the phage surface. Consequently, immunogenic proteins can be selected from these libraries using disease-related immunoglobulins from patient serum. ORFeome phage display in particular allows the identification of immunogenic proteins that are only expressed in the host-pathogen interaction but not in cultivation, as well as the detection of very low expressed and very small immunogens and immunogenic proteins of non-cultivable organisms. The identified immunogenic proteins are potential biomarkers for the development of diagnostic assays or vaccines. These articles will give an introduction to ORFeome phage-display technology and give detailed protocols to identify immunogenic proteins by phage display.

  20. Safety analysis of a Russian phage cocktail: from metagenomic analysis to oral application in healthy human subjects.

    PubMed

    McCallin, Shawna; Alam Sarker, Shafiqul; Barretto, Caroline; Sultana, Shamima; Berger, Bernard; Huq, Sayeda; Krause, Lutz; Bibiloni, Rodrigo; Schmitt, Bertrand; Reuteler, Gloria; Brüssow, Harald

    2013-09-01

    Phage therapy has a long tradition in Eastern Europe, where preparations are comprised of complex phage cocktails whose compositions have not been described. We investigated the composition of a phage cocktail from the Russian pharmaceutical company Microgen targeting Escherichia coli/Proteus infections. Electron microscopy identified six phage types, with numerically T7-like phages dominating over T4-like phages. A metagenomic approach using taxonomical classification, reference mapping and de novo assembly identified 18 distinct phage types, including 7 genera of Podoviridae, 2 established and 2 proposed genera of Myoviridae, and 2 genera of Siphoviridae. De novo assembly yielded 7 contigs greater than 30 kb, including a 147-kb Myovirus genome and a 42-kb genome of a potentially new phage. Bioinformatic analysis did not reveal undesired genes and a small human volunteer trial did not associate adverse effects with oral phage exposure. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Effects of abortion legalization in Nepal, 2001-2010.

    PubMed

    Henderson, Jillian T; Puri, Mahesh; Blum, Maya; Harper, Cynthia C; Rana, Ashma; Gurung, Geeta; Pradhan, Neelam; Regmi, Kiran; Malla, Kasturi; Sharma, Sudha; Grossman, Daniel; Bajracharya, Lata; Satyal, Indira; Acharya, Shridhar; Lamichhane, Prabhat; Darney, Philip D

    2013-01-01

    Abortion was legalized in Nepal in 2002, following advocacy efforts highlighting high maternal mortality from unsafe abortion. We sought to assess whether legalization led to reductions in the most serious maternal health consequences of unsafe abortion. We conducted retrospective medical chart review of all gynecological cases presenting at four large public referral hospitals in Nepal. For the years 2001-2010, all cases of spontaneous and induced abortion complications were identified, abstracted, and coded to classify cases of serious infection, injury, and systemic complications. We used segmented Poisson and ordinary logistic regression to test for trend and risks of serious complications for three time periods: before implementation (2001-2003), early implementation (2004-2006), and later implementation (2007-2010). 23,493 cases of abortion complications were identified. A significant downward trend in the proportion of serious infection, injury, and systemic complications was observed for the later implementation period, along with a decline in the risk of serious complications (OR 0.7, 95% CI 0.64, 0.85). Reductions in sepsis occurred sooner, during early implementation (OR 0.6, 95% CI 0.47, 0.75). Over the study period, health care use and the population of reproductive aged women increased. Total fertility also declined by nearly half, despite relatively low contraceptive prevalence. Greater numbers of women likely obtained abortions and sought hospital care for complications following legalization, yet we observed a significant decline in the rate of serious abortion morbidity. The liberalization of abortion policy in Nepal has benefited women's health, and likely contributes to falling maternal mortality in the country. The steepest decline was observed after expansion of the safe abortion program to include midlevel providers, second trimester training, and medication abortion, highlighting the importance of concerted efforts to improve access. Other

  2. Liposome-Encapsulated Bacteriophages for Enhanced Oral Phage Therapy against Salmonella spp.

    PubMed

    Colom, Joan; Cano-Sarabia, Mary; Otero, Jennifer; Cortés, Pilar; Maspoch, Daniel; Llagostera, Montserrat

    2015-07-01

    Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units. The liposome coating also improved the retention of bacteriophages in the chicken intestinal tract. When cocktails of the encapsulated and nonencapsulated phages were administered to broilers, after 72 h the encapsulated phages were detected in 38.1% of the animals, whereas the nonencapsulated phages were present in only 9.5%. The difference was significant. In addition, in an in vitro experiment, the cecal contents of broilers promoted the release of the phages from the liposomes. In broilers experimentally infected with Salmonella, the daily administration of the two cocktails for 6 days postinfection conferred similar levels of protection against Salmonella colonization. However, once treatment was stopped, protection by the nonencapsulated phages disappeared, whereas that provided by the encapsulated phages persisted for at least 1 week, showing the enhanced efficacy of the encapsulated phages in protecting poultry against Salmonella over time. The methodology described here allows the liposome encapsulation of phages of different morphologies. The preparations can be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  3. Induced abortion: an overview for internists.

    PubMed

    Grimes, David A; Creinin, Mitchell D

    2004-04-20

    Internists care for many women who have had abortions and many who will seek abortions in the future. Each year, about 2% of all women of reproductive age have an abortion. Women having abortions tend to be young, white, unmarried, and early in pregnancy. Most abortions are done by suction curettage under local anesthesia in a freestanding clinic. However, medical abortion is growing in popularity as a nonsurgical alternative. The regimen approved by the U.S. Food and Drug Administration specifies mifepristone, 600 mg orally, followed 2 days later by misoprostol, 400 microg orally (within 49 days from last menses). Recent studies have recommended alternative approaches, such as mifepristone, 200 mg orally, followed in 1 to 3 days by misoprostol, 800 microg vaginally (up to 63 days). Medical abortion can be provided by a broader variety of physicians than can surgical abortion. The overall case-fatality rate for abortion is less than 1 death per 100,000 procedures. Infection, hemorrhage, acute hematometra, and retained tissue are among the more common complications. Referral back to the original abortion provider for management is advisable. Overall, induced abortion does not lead to late sequelae, either medical or psychiatric. Of importance, no link exists between induced abortion and later breast cancer. For physicians who are asked to help with a referral, the National Abortion Federation and Planned Parenthood Federation of America have helpful Web sites and networks of high-quality clinics. The cost of abortion (currently about 372 dollars at 10 weeks) has decreased in recent decades. Provision of ongoing contraception and encouragement of emergency contraception can reduce unintended pregnancies and the need for abortion.

  4. Phage Biodiversity in Artisanal Cheese Wheys Reflects the Complexity of the Fermentation Process

    PubMed Central

    Mahony, Jennifer; Moscarelli, Angelo; Kelleher, Philip; Lugli, Gabriele A.; Ventura, Marco; Settanni, Luca; van Sinderen, Douwe

    2017-01-01

    Dairy fermentations constitute a perfect “breeding ground” for bacteriophages infecting starter cultures, particularly strains of Lactococcus lactis. In modern fermentations, these phages typically belong to one of three groups, i.e., the 936, P335, and c2 phage groups. Traditional production methods present fewer chemical and physical barriers to phage proliferation compared to modern production systems, while the starter cultures used are typically complex, variable, and undefined. In the current study, a variety of cheese whey, animal-derived rennet, and vat swab samples from artisanal cheeses produced in Sicily were analysed for the presence of lactococcal phages to assess phage diversity in such environments. The complete genomes of 18 representative phage isolates were sequenced, allowing the identification of 10 lactococcal 949 group phages, six P087 group phages, and two members of the 936 group phages. The genetic diversity of these isolates was examined using phylogenetic analysis as well as a focused analysis of the receptor binding proteins, which dictate specific interactions with the host-encoded receptor. Thermal treatments at 63 °C and 83 °C indicate that the 949 phages are particularly sensitive to thermal treatments, followed by the P087 and 936 isolates, which were shown to be much less sensitive to such treatments. This difference may explain the relatively low frequency of isolation of the so-called “rare” 949 and P087 group phages in modern fermentations. PMID:28300778

  5. Standardizing the classification of abortion incidents: the Procedural Abortion Incident Reporting and Surveillance (PAIRS) Framework.

    PubMed

    Taylor, Diana; Upadhyay, Ushma D; Fjerstad, Mary; Battistelli, Molly F; Weitz, Tracy A; Paul, Maureen E

    2017-07-01

    To develop and validate standardized criteria for assessing abortion-related incidents (adverse events, morbidities, near misses) for first-trimester aspiration abortion procedures and to demonstrate the utility of a standardized framework [the Procedural Abortion Incident Reporting & Surveillance (PAIRS) Framework] for estimating serious abortion-related adverse events. As part of a California-based study of early aspiration abortion provision conducted between 2007 and 2013, we developed and validated a standardized framework for defining and monitoring first-trimester (≤14weeks) aspiration abortion morbidity and adverse events using multiple methods: a literature review, framework criteria testing with empirical data, repeated expert reviews and data-based revisions to the framework. The final framework distinguishes incidents resulting from procedural abortion care (adverse events) from morbidity related to pregnancy, the abortion process and other nonabortion related conditions. It further classifies incidents by diagnosis (confirmatory data, etiology, risk factors), management (treatment type and location), timing (immediate or delayed), seriousness (minor or major) and outcome. Empirical validation of the framework using data from 19,673 women receiving aspiration abortions revealed almost an equal proportion of total adverse events (n=205, 1.04%) and total abortion- or pregnancy-related morbidity (n=194, 0.99%). The majority of adverse events were due to retained products of conception (0.37%), failed attempted abortion (0.15%) and postabortion infection (0.17%). Serious or major adverse events were rare (n=11, 0.06%). Distinguishing morbidity diagnoses from adverse events using a standardized, empirically tested framework confirms the very low frequency of serious adverse events related to clinic-based abortion care. The PAIRS Framework provides a useful set of tools to systematically classify and monitor abortion-related incidents for first

  6. Phage transposon mutagenesis.

    PubMed

    Siegrist, M Sloan; Rubin, Eric J

    2009-01-01

    Phage transduction is an attractive method of genetic manipulation in mycobacteria. PhiMycoMarT7 is well suited for transposon mutagenesis as it is temperature sensitive for replication and contains T7 promoters that promote transcription, a highly active transposase gene, and an Escherichia coli oriR6 K origin of replication. Mycobacterial transposon mutant libraries produced by PhiMycoMarT7 transduction are amenable to both forward and reverse genetic studies. In this protocol, we detail the preparation of PhiMycoMarT7, including a description of the phage, reconstitution of the phage, purification of plaques, preparation of phage stock, and titering of phage stock. We then describe the transduction procedure and finally outline the isolation of individual transposon mutants.

  7. Efficacy of bacteriophage therapy in a model of Burkholderia cenocepacia pulmonary infection

    PubMed Central

    Carmody, Lisa A.; Gill, Jason J.; Summer, Elizabeth J.; Sajjan, Uma S.; Gonzalez, Carlos F.; Young, Ryland F.; LiPuma, John J.

    2009-01-01

    The therapeutic potential of bacteriophage (phage) in a mouse model of acute B. cenocepacia pulmonary infection was assessed. Phage were administered by either intranasal (i.n.) inhalation or intraperitoneal (i.p.) injection. Bacterial density, macrophage inflammatory protein-2 (MIP-2), and tumor necrosis factor-α (TNFα) levels were significantly reduced in lungs of mice treated with i.p. phage. No significant differences in lung bacterial density or MIP-2 levels were found between untreated mice and mice treated with i.n. phage, i.p. UV-inactivated phage, or i.p. λ phage controls. Mock-infected mice treated with phage showed no significant increase in lung MIP-2 or TNFα levels compared to mock-infected / mock-treated mice. We have demonstrated the efficacy of phage therapy in an acute B. cenocepacia lung infection model. Systemic administration of phage was more effective than inhalational administration, suggesting that circulating phage have better access to bacteria in lung compared to topical phage. PMID:20001604

  8. Structure of a group A streptococcal phage-encoded virulence factor reveals a catalytically active triple-stranded beta-helix.

    PubMed

    Smith, Nicola L; Taylor, Edward J; Lindsay, Anna-Marie; Charnock, Simon J; Turkenburg, Johan P; Dodson, Eleanor J; Davies, Gideon J; Black, Gary W

    2005-12-06

    Streptococcus pyogenes (group A Streptococcus) causes severe invasive infections including scarlet fever, pharyngitis (streptococcal sore throat), skin infections, necrotizing fasciitis (flesh-eating disease), septicemia, erysipelas, cellulitis, acute rheumatic fever, and toxic shock. The conversion from nonpathogenic to toxigenic strains of S. pyogenes is frequently mediated by bacteriophage infection. One of the key bacteriophage-encoded virulence factors is a putative "hyaluronidase," HylP1, a phage tail-fiber protein responsible for the digestion of the S. pyogenes hyaluronan capsule during phage infection. Here we demonstrate that HylP1 is a hyaluronate lyase. The 3D structure, at 1.8-angstroms resolution, reveals an unusual triple-stranded beta-helical structure and provides insight into the structural basis for phage tail assembly and the role of phage tail proteins in virulence. Unlike the triple-stranded beta-helix assemblies of the bacteriophage T4 injection machinery and the tailspike endosialidase of the Escherichia coli K1 bacteriophage K1F, HylP1 possesses three copies of the active center on the triple-helical fiber itself without the need for an accessory catalytic domain. The triple-stranded beta-helix is not simply a structural scaffold, as previously envisaged; it is harnessed to provide a 200-angstroms-long substrate-binding groove for the optimal reduction in hyaluronan viscosity to aid phage penetration of the capsule.

  9. PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

    PubMed Central

    Price, Winston H.

    1948-01-01

    1. The release of S. muscae phage in veal infusion medium is correlated with lysis of the host. 2. The release of the bacterial virus in Fildes' synthetic medium occurs in a step-wise manner before observable lysis of the cells occurs. This result has been confirmed by both turbidimetric readings and direct microscopic examination of the infected cells. PMID:18891146

  10. Salmonella typhimurium phage type 141 infections in Sheffield during 1984 and 1985: association with hens' eggs.

    PubMed Central

    Chapman, P. A.; Rhodes, P.; Rylands, W.

    1988-01-01

    Food poisoning due to Salmonella typhimurium phage type 141 was unusual in the Sheffield area before 1984. The sudden increase in incidence of this phage type during 1984 and 1985, and its causative role in several small outbreaks in this period have been investigated. Epidemiological and laboratory investigations suggested that hens' eggs were the most likely source of S. typhimurium phage type 141. PMID:3042440

  11. Overexpression of Escherichia coli udk mimics the absence of T7 Gp2 function and thereby abrogates successful infection by T7 phage.

    PubMed

    Shadrin, Andrey; Sheppard, Carol; Savalia, Dhruti; Severinov, Konstantin; Wigneshweraraj, Sivaramesh

    2013-02-01

    Successful infection of Escherichia coli by bacteriophage T7 relies upon the transcription of the T7 genome by two different RNA polymerases (RNAps). The bacterial RNAp transcribes early T7 promoters, whereas middle and late T7 genes are transcribed by the T7 RNAp. Gp2, a T7-encoded transcription factor, is a 7 kDa product of an essential middle T7 gene 2, and is a potent inhibitor of the host RNAp. The essential biological role of Gp2 is to inhibit transcription of early T7 genes that fail to terminate efficiently in order to facilitate the coordinated usage of the T7 genome by both host and phage RNAps. Overexpression of the E. coli udk gene, which encodes a uridine/cytidine kinase, interferes with T7 infection. We demonstrate that overexpression of udk antagonizes Gp2 function in E. coli in the absence of T7 infection and thus independently of T7-encoded factors. It seems that overexpression of udk reduces Gp2 stability and functionality during T7 infection, which consequently results in inadequate inhibition of host RNAp and in the accumulation of early T7 transcripts. In other words, overexpression of udk mimics the absence of Gp2 during T7 infection. Our study suggests that the transcriptional regulation of the T7 genome is surprisingly complex and might potentially be affected at many levels by phage- and host-encoded factors.

  12. Characterization of Five Novel Brevibacillus Bacteriophages and Genomic Comparison of Brevibacillus Phages

    PubMed Central

    Berg, Jordan A.; Merrill, Bryan D.; Crockett, Justin T.; Esplin, Kyle P.; Evans, Marlee R.; Heaton, Karli E.; Hilton, Jared A.; Hyde, Jonathan R.; McBride, Morgan S.; Schouten, Jordan T.; Simister, Austin R.; Thurgood, Trever L.; Ward, Andrew T.; Breakwell, Donald P.; Hope, Sandra; Grose, Julianne H.

    2016-01-01

    Brevibacillus laterosporus is a spore-forming bacterium that causes a secondary infection in beehives following European Foulbrood disease. To better understand the contributions of Brevibacillus bacteriophages to the evolution of their hosts, five novel phages (Jenst, Osiris, Powder, SecTim467, and Sundance) were isolated and characterized. When compared with the five Brevibacillus phages currently in NCBI, these phages were assigned to clusters based on whole genome and proteome synteny. Powder and Osiris, both myoviruses, were assigned to the previously described Jimmer-like cluster. SecTim467 and Jenst, both siphoviruses, formed a novel phage cluster. Sundance, a siphovirus, was assigned as a singleton phage along with the previously isolated singleton, Emery. In addition to characterizing the basic relationships between these phages, several genomic features were observed. A motif repeated throughout phages Jenst and SecTim467 was frequently upstream of genes predicted to function in DNA replication, nucleotide metabolism, and transcription, suggesting transcriptional co-regulation. In addition, paralogous gene pairs that encode a putative transcriptional regulator were identified in four Brevibacillus phages. These paralogs likely evolved to bind different DNA sequences due to variation at amino acid residues predicted to bind specific nucleotides. Finally, a putative transposable element was identified in SecTim467 and Sundance that carries genes homologous to those found in Brevibacillus chromosomes. Remnants of this transposable element were also identified in phage Jenst. These discoveries provide a greater understanding of the diversity of phages, their behavior, and their evolutionary relationships to one another and to their host. In addition, they provide a foundation with which further Brevibacillus phages can be compared. PMID:27304881

  13. Characterization and complete genome sequence analysis of a novel virulent Siphoviridae phage against Staphylococcus aureus isolated from bovine mastitis in Xinjiang, China.

    PubMed

    Zhang, Qian; Xing, Shaozhen; Sun, Qiang; Pei, Guangqian; Cheng, Shi; Liu, Yannan; An, Xiaoping; Zhang, Xianglilan; Qu, Yonggang; Tong, Yigang

    2017-06-01

    Bovine mastitis is one of the most costly diseases in dairy cows worldwide. It can be caused by over 150 different microorganisms, where Staphylococcus aureus is the most frequently isolated and a major pathogen responsible for heavy economic losses in dairy industry. Although antibiotic therapy is most widely used, alternative treatments are necessary due to the increasing antibiotic resistance. Using phage for pathogen control is a promising tool in the fight against antibiotic resistance. Mainly using high-throughput sequencing, bioinformatics and our proposed phage termini identification method, we have isolated and characterized a novel virulent phage, designated as vB_SauS_IMEP5, from manure collected from dairy farms in Shihezi, Xinjiang, China, for use as a biocontrol agent against Staphylococcus aureus infections. Its latent period was about 30 min and its burst size was approximately 272PFU/cell. Phage vB_SauS_IMEP5 survives in a wide pH range between 3 and 12. A treatment at 70 °C for 20 min can inactive the phage. Morphological analysis of vB_SauS_IMEP5 revealed that phage vB_SauS_IMEP5 morphologically resembles phages in the family Siphoviridae. Among our tested multiplicity of infections (MOIs), the optimal multiplicity of infection (MOI) of this phage was determined to be 0.001, suggesting that phage vB_SauS_IMEP5 has high bacteriolytic potential and good efficiency for reducing bacterial growth. The complete genome of IME-P5 is a 44,677-bp, linear, double-stranded DNA, with a G+C content of 34.26%, containing 69 putative ORFs. The termini of genome were determined with next-generation sequencing data using our previously proposed termini identification method, which suggests that this phage has non-redundant termini with 9nt 3' protruding cohesive ends. The genomic and proteomic characteristics of IMEP5 demonstrate that this phage does not belong to any of the previously recognized Siphoviridae Staphylococcus phage groups, suggesting the

  14. Synergy and Order Effects of Antibiotics and Phages in Killing Pseudomonas aeruginosa Biofilms

    PubMed Central

    Chaudhry, Waqas Nasir; Concepción-Acevedo, Jeniffer; Park, Taehyun; Andleeb, Saadia; Bull, James J.

    2017-01-01

    In contrast to planktonic cells, bacteria imbedded biofilms are notoriously refractory to treatment by antibiotics or bacteriophage (phage) used alone. Given that the mechanisms of killing differ profoundly between drugs and phages, an obvious question is whether killing is improved by combining antibiotic and phage therapy. However, this question has only recently begun to be explored. Here, in vitro biofilm populations of Pseudomonas aeruginosa PA14 were treated singly and with combinations of two phages and bactericidal antibiotics of five classes. By themselves, phages and drugs commonly had only modest effects in killing the bacteria. However some phage-drug combinations reduced bacterial densities to well below that of the best single treatment; in some cases, bacterial densities were reduced even below the level expected if both agents killed independently of each other (synergy). Furthermore, there was a profound order effect in some cases: treatment with phages before drugs achieved maximum killing. Combined treatment was particularly effective in killing in Pseudomonas biofilms grown on layers of cultured epithelial cells. Phages were also capable of limiting the extent to which minority populations of bacteria resistant to the treating antibiotic ascend. The potential of combined antibiotic and phage treatment of biofilm infections is discussed as a realistic way to evaluate and establish the use of bacteriophage for the treatment of humans. PMID:28076361

  15. Evidence of Geobacter-associated phage in a uranium-contaminated aquifer

    PubMed Central

    Holmes, Dawn E; Giloteaux, Ludovic; Chaurasia, Akhilesh K; Williams, Kenneth H; Luef, Birgit; Wilkins, Michael J; Wrighton, Kelly C; Thompson, Courtney A; Comolli, Luis R; Lovley, Derek R

    2015-01-01

    Geobacter species may be important agents in the bioremediation of organic and metal contaminants in the subsurface, but as yet unknown factors limit the in situ growth of subsurface Geobacter well below rates predicted by analysis of gene expression or in silico metabolic modeling. Analysis of the genomes of five different Geobacter species recovered from contaminated subsurface sites indicated that each of the isolates had been infected with phage. Geobacter-associated phage sequences were also detected by metagenomic and proteomic analysis of samples from a uranium-contaminated aquifer undergoing in situ bioremediation, and phage particles were detected by microscopic analysis in groundwater collected from sediment enrichment cultures. Transcript abundance for genes from the Geobacter-associated phage structural proteins, tail tube Gp19 and baseplate J, increased in the groundwater in response to the growth of Geobacter species when acetate was added, and then declined as the number of Geobacter decreased. Western blot analysis of a Geobacter-associated tail tube protein Gp19 in the groundwater demonstrated that its abundance tracked with the abundance of Geobacter species. These results suggest that the enhanced growth of Geobacter species in the subsurface associated with in situ uranium bioremediation increased the abundance and activity of Geobacter-associated phage and show that future studies should focus on how these phages might be influencing the ecology of this site. PMID:25083935

  16. Four linked outbreaks of Salmonella enteritidis phage type 4 infection--the continuing egg threat.

    PubMed

    Ejidokun, O O; Killalea, D; Cooper, M; Holmyard, S; Cross, A; Kemp, C

    2000-06-01

    Four outbreaks of Salmonella enteritidis phage type (PT) 4 occurred among guests at functions for which a single commercial caterer supplied food. Retrospective cohort studies were used to describe the epidemiology of three of these outbreaks and identify the vehicle(s) responsible. Of 172 guests at these three events, 47 fitted the clinical case definition for illness and 24 cases were confirmed to have S. enteritidis PT4 infection. Food containing raw egg was identified epidemiologically as the likely vehicle of infection in two of the three outbreaks (odds ratios (OR) and 95% confidence intervals 9.1 (2.2-39.9) and 6.9 (1.2-46.4)). Logistic regression analysis yielded OR = 10.7 (p = 0.0022) and OR = 9.3 (p = 0.015) for egg consumption in two of the outbreaks. These outbreaks highlighted the continuing need to remind the public and commercial caterers of the potential high risks of contracting salmonella from shell eggs. Education of caterers includes advice to obtain eggs and other products from reputable and identifiable suppliers.

  17. Phage-Mediated Gene Therapy.

    PubMed

    Hosseinidoust, Zeinab

    2017-01-01

    Bacteriophages (bacterial viruses) have long been under investigation as vectors for gene therapy. Similar to other viral vectors, the phage coat proteins have evolved over millions of years to protect the viral genome from degradation post injection, offering protection for the valuable therapeutic sequence. However, what sets phage apart from other viral gene delivery vectors is their safety for human use and the relative ease by which foreign molecules can be expressed on the phage outer surface, enabling highly targeted gene delivery. The latter property also makes phage a popular choice for gene therapy target discovery through directed evolution. Although promising, phage-mediated gene therapy faces several outstanding challenges, the most notable being lower gene delivery efficiency compared to animal viruses, vector stability, and nondesirable immune stimulation. This review presents a critical review of promises and challenges of employing phage as gene delivery vehicles as well as an introduction to the concept of phage-based microbiome therapy as the new frontier and perhaps the most promising application of phage-based gene therapy. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. Heterogeneity in Induction Level, Infection Ability, and Morphology of Shiga Toxin-Encoding Phages (Stx Phages) from Dairy and Human Shiga Toxin-Producing Escherichia coli O26:H11 Isolates

    PubMed Central

    Bonanno, Ludivine; Petit, Marie-Agnès; Loukiadis, Estelle; Michel, Valérie

    2016-01-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) bacteria are foodborne pathogens responsible for diarrhea and hemolytic-uremic syndrome (HUS). Shiga toxin, the main STEC virulence factor, is encoded by the stx gene located in the genome of a bacteriophage inserted into the bacterial chromosome. The O26:H11 serotype is considered to be the second-most-significant HUS-causing serotype worldwide after O157:H7. STEC O26:H11 bacteria and their stx-negative counterparts have been detected in dairy products. They may convert from the one form to the other by loss or acquisition of Stx phages, potentially confounding food microbiological diagnostic methods based on stx gene detection. Here we investigated the diversity and mobility of Stx phages from human and dairy STEC O26:H11 strains. Evaluation of their rate of in vitro induction, occurring either spontaneously or in the presence of mitomycin C, showed that the Stx2 phages were more inducible overall than Stx1 phages. However, no correlation was found between the Stx phage levels produced and the origin of the strains tested or the phage insertion sites. Morphological analysis by electron microscopy showed that Stx phages from STEC O26:H11 displayed various shapes that were unrelated to Stx1 or Stx2 types. Finally, the levels of sensitivity of stx-negative E. coli O26:H11 to six Stx phages differed among the 17 strains tested and our attempts to convert them into STEC were unsuccessful, indicating that their lysogenization was a rare event. PMID:26826235

  19. Complete Genome Sequence of EtG, the First Phage Sequenced from Erwinia tracheiphila.

    PubMed

    Andrade-Domínguez, Andrés; Kolter, Roberto; Shapiro, Lori R

    2018-02-22

    Erwinia tracheiphila is the causal agent of bacterial wilt of cucurbits. Here, we report the genome sequence of the temperate phage EtG, which was isolated from an E. tracheiphila -infected cucumber plant. Phage EtG has a linear 30,413-bp double-stranded DNA genome with cohesive ends and 45 predicted open reading frames. Copyright © 2018 Andrade-Domínguez et al.

  20. Studies with infections fragments of phage DNA. Final report, January 1, 1970--June 30, 1976

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schachtele, C. F.

    The minute, virulent and structurally intricate Bacillus subtilis bacteriophage phi 29 was utilized to study in vivo viral development. Purified strands of phi 29 DNA were used to analyze transcription of the viral genome. Early mRNA hybridizes to the light DNA strand which controls DNA replication and other early functions. Late mRNA hybridizes to the heavy DNA strand which codes for phage structural proteins. The temporal sequence of specific viral protein synthesis was analyzed by gel electrophoresis and was shown to directly correlate with the RNA transcription pattern. The genes carried by phi 29 have been marked with ts andmore » sus mutations and mapped by appropriate crosses yielding a linear map of 17 cistrons. Fragments of the phi 29 DNA were shown to retain their biological activity and marker rescue studies indicated that gene transfer could be performed with pieces having a molecular weight of less than 1 million daltons. Mutant infection under nonpermissive conditions and the analysis of precursor structures has allowed the formation of a tentative morphogenetic pathway leading to the formation of infectious particles. Work with phi 29 has established this virus as an advantageous model system for studying a variety of problems in molecular biology and approximately a dozen laboratories in the country and abroad are working with this phage.« less

  1. Regulation of infection efficiency in a globally abundant marine Bacteriodetes virus

    DOE PAGES

    Howard-Varona, Cristina; Roux, Simon; Dore, Hugo; ...

    2016-05-17

    Microbes impact human health and disease, industrial processes and natural ecosystems, but do so under the influence of viruses. Problematically, knowledge of viral infection efficiencies and outcomes (e.g. lysis, lysogeny) derives from few model systems that over-represent efficient, lytic infections and under-represent virus-host natural diversity. Here we sought to understand how infection efficiency is regulated in an environmental Bacteroidetes virus that represents a globally abundant viral group and has drastically different infection efficiencies when infecting two nearly identical bacterial strains. To this end, we quantified bacterial virus (phage) and host DNA, transcripts and phage particles throughout the infection of bothmore » bacterial hosts. While the phage transcriptome was similar during both infections, host transcriptional differences appeared to have altered infection efficiency. Specifically, host transcriptomes suggested that the phage failed to repress early host expression in the inefficient nfection, thereby allowing the host to respond against infection by delaying phage DNA replication and protein translation. Further measurements showed that phage DNA and particle production were delayed (by >30 minutes) and reduced (by >50%) in the inefficient versus efficient infection as the host over-expressed DNA degradation genes and under-expressed translation genes, respectively. Together these results suggest that multiple levels of regulation can impact infection efficiencies as failure to repress host transcription allowed the host to defend against both phage DNA and protein production. Given that this phage type is ubiquitous and abundant in the global oceans and that variably efficient viral infections are likely common in any ecosystem with varying phage-host abundances and physiological states, these data provide a critically needed foundation for understanding and modeling viral infection efficiency in nature.« less

  2. Regulation of infection efficiency in a globally abundant marine Bacteriodetes virus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Howard-Varona, Cristina; Roux, Simon; Dore, Hugo

    Microbes impact human health and disease, industrial processes and natural ecosystems, but do so under the influence of viruses. Problematically, knowledge of viral infection efficiencies and outcomes (e.g. lysis, lysogeny) derives from few model systems that over-represent efficient, lytic infections and under-represent virus-host natural diversity. Here we sought to understand how infection efficiency is regulated in an environmental Bacteroidetes virus that represents a globally abundant viral group and has drastically different infection efficiencies when infecting two nearly identical bacterial strains. To this end, we quantified bacterial virus (phage) and host DNA, transcripts and phage particles throughout the infection of bothmore » bacterial hosts. While the phage transcriptome was similar during both infections, host transcriptional differences appeared to have altered infection efficiency. Specifically, host transcriptomes suggested that the phage failed to repress early host expression in the inefficient nfection, thereby allowing the host to respond against infection by delaying phage DNA replication and protein translation. Further measurements showed that phage DNA and particle production were delayed (by >30 minutes) and reduced (by >50%) in the inefficient versus efficient infection as the host over-expressed DNA degradation genes and under-expressed translation genes, respectively. Together these results suggest that multiple levels of regulation can impact infection efficiencies as failure to repress host transcription allowed the host to defend against both phage DNA and protein production. Given that this phage type is ubiquitous and abundant in the global oceans and that variably efficient viral infections are likely common in any ecosystem with varying phage-host abundances and physiological states, these data provide a critically needed foundation for understanding and modeling viral infection efficiency in nature.« less

  3. Inhibition of bacterial conjugation by phage M13 and its protein g3p: quantitative analysis and model.

    PubMed

    Lin, Abraham; Jimenez, Jose; Derr, Julien; Vera, Pedro; Manapat, Michael L; Esvelt, Kevin M; Villanueva, Laura; Liu, David R; Chen, Irene A

    2011-01-01

    Conjugation is the main mode of horizontal gene transfer that spreads antibiotic resistance among bacteria. Strategies for inhibiting conjugation may be useful for preserving the effectiveness of antibiotics and preventing the emergence of bacterial strains with multiple resistances. Filamentous bacteriophages were first observed to inhibit conjugation several decades ago. Here we investigate the mechanism of inhibition and find that the primary effect on conjugation is occlusion of the conjugative pilus by phage particles. This interaction is mediated primarily by phage coat protein g3p, and exogenous addition of the soluble fragment of g3p inhibited conjugation at low nanomolar concentrations. Our data are quantitatively consistent with a simple model in which association between the pili and phage particles or g3p prevents transmission of an F plasmid encoding tetracycline resistance. We also observe a decrease in the donor ability of infected cells, which is quantitatively consistent with a reduction in pili elaboration. Since many antibiotic-resistance factors confer susceptibility to phage infection through expression of conjugative pili (the receptor for filamentous phage), these results suggest that phage may be a source of soluble proteins that slow the spread of antibiotic resistance genes.

  4. Inhibition of Bacterial Conjugation by Phage M13 and Its Protein g3p: Quantitative Analysis and Model

    PubMed Central

    Lin, Abraham; Jimenez, Jose; Derr, Julien; Vera, Pedro; Manapat, Michael L.; Esvelt, Kevin M.; Villanueva, Laura; Liu, David R.; Chen, Irene A.

    2011-01-01

    Conjugation is the main mode of horizontal gene transfer that spreads antibiotic resistance among bacteria. Strategies for inhibiting conjugation may be useful for preserving the effectiveness of antibiotics and preventing the emergence of bacterial strains with multiple resistances. Filamentous bacteriophages were first observed to inhibit conjugation several decades ago. Here we investigate the mechanism of inhibition and find that the primary effect on conjugation is occlusion of the conjugative pilus by phage particles. This interaction is mediated primarily by phage coat protein g3p, and exogenous addition of the soluble fragment of g3p inhibited conjugation at low nanomolar concentrations. Our data are quantitatively consistent with a simple model in which association between the pili and phage particles or g3p prevents transmission of an F plasmid encoding tetracycline resistance. We also observe a decrease in the donor ability of infected cells, which is quantitatively consistent with a reduction in pili elaboration. Since many antibiotic-resistance factors confer susceptibility to phage infection through expression of conjugative pili (the receptor for filamentous phage), these results suggest that phage may be a source of soluble proteins that slow the spread of antibiotic resistance genes. PMID:21637841

  5. Isolation and Characterization of Lytic Phage vB_EcoM_JS09 against Clinically Isolated Antibiotic-Resistant Avian Pathogenic Escherichia coli and Enterotoxigenic Escherichia coli.

    PubMed

    Zhou, Yan; Bao, Hongduo; Zhang, Hui; Wang, Ran

    2015-01-01

    To characterize the lytic coliphage vB_EcoM_JS09 (phage JS09) isolated from sewage samples of a swine farm in Jiangsu Province, China, which infects antibiotic-resistant avian pathogenic Escherichia coli (APEC) and enterotoxigenic E. coli (ETEC). Transmission electron microscopy revealed that phage JS09 has an isometric icosahedral head (76 nm in diameter) and a long contractile tail (140 nm in length) and features a T-even morphology. Its latent period was 30 min and the average burst size was 79 phage particles per infected cell. It attached to the host cells within 9 min. JS09 could infect 16 clinically isolated APEC and ETEC strains and the laboratory-engineered E. coli K and B strains. Ten of the clinical isolates of E. coli were resistant to antibiotics. At a multiplicity of infection of 10, 3, 1, or 0.3, the phage caused rapid cell lysis within 2 h, resulting in 5- to 10-fold reductions in cell concentration. Sequencing of the JS09 genome revealed a 169.148-kb linear but circularly permuted and terminally redundant dsDNA with 37.98% G+C content. Two hundred seventy-three open reading frames were predicted to be coding sequences, 135 of which were functionally defined and organized in a modular format which includes modules for DNA replication, DNA packaging, structural proteins, and host cell lysis proteins. Phage JS09 is assigned to the Caudovirales order (Myoviridae phage family), and it is considered a T4-like phage based on its morphological, genomic, and growth characteristics. JS09 gp37, a receptor-binding protein (RBP) important for host cell infection, shares little homology with other RBP in the NCBI database, which suggests that the variable regions in gp37 determine the unique host range of phage JS09. Protein sequence comparisons cluster the putative 'RBP' of JS09 much more closely with those of Yersinia phage phiD1, phage TuIa, and phage TuIb. A novel lytic coliphage named JS09 was isolated from sewage samples of a swine farm in Jiangsu Province

  6. Well-temperate phage: Optimal bet-hedging against local environmental collapses

    DOE PAGES

    Maslov, Sergei; Sneppen, Kim

    2015-06-02

    Upon infection of their bacterial hosts temperate phages must chose between lysogenic and lytic developmental strategies. Here we apply the game-theoretic bet-hedging strategy introduced by Kelly to derive the optimal lysogenic fraction of the total population of phages as a function of frequency and intensity of environmental downturns affecting the lytic subpopulation. “Well-temperate” phage from our title is characterized by the best long-term population growth rate. We show that it is realized when the lysogenization frequency is approximately equal to the probability of lytic population collapse. We further predict the existence of sharp boundaries in system’s environmental, ecological, and biophysicalmore » parameters separating the regions where this temperate strategy is optimal from those dominated by purely virulent or dormant (purely lysogenic) strategies. We show that the virulent strategy works best for phages with large diversity of hosts, and access to multiple independent environments reachable by diffusion. Conversely, progressively more temperate or even dormant strategies are favored in the environments, that are subject to frequent and severe temporal downturns.« less

  7. Well-temperate phage: Optimal bet-hedging against local environmental collapses

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maslov, Sergei; Sneppen, Kim

    Upon infection of their bacterial hosts temperate phages must chose between lysogenic and lytic developmental strategies. Here we apply the game-theoretic bet-hedging strategy introduced by Kelly to derive the optimal lysogenic fraction of the total population of phages as a function of frequency and intensity of environmental downturns affecting the lytic subpopulation. “Well-temperate” phage from our title is characterized by the best long-term population growth rate. We show that it is realized when the lysogenization frequency is approximately equal to the probability of lytic population collapse. We further predict the existence of sharp boundaries in system’s environmental, ecological, and biophysicalmore » parameters separating the regions where this temperate strategy is optimal from those dominated by purely virulent or dormant (purely lysogenic) strategies. We show that the virulent strategy works best for phages with large diversity of hosts, and access to multiple independent environments reachable by diffusion. Conversely, progressively more temperate or even dormant strategies are favored in the environments, that are subject to frequent and severe temporal downturns.« less

  8. Specialized Transducing Phages Derived from Salmonella Phage P22

    PubMed Central

    Hoppe, Ingrid; Roth, John

    1974-01-01

    Salmonella phage P22 has been used in the construction of three sorts of specialized transducing phage: P22 proAB, P22 proABlac and P22 argF. The bacterial genes carried are derived from E. coli K12. Since E. coli and Salmonella chromosomes recombine very poorly, E. coli genes cannot be transduced into Salmonella recipients by P22's generalized transduction mechanism. Therefore, stable inheritance of E. coli material provides a means of detecting specialized transduction. Formation of these phages was possible because the P22 prophage recognizes an attachment site in the E. coli F' prolac episome. Salmonella strains carrying the F' prolac episome can be lysogenized by P22 so as to leave the prophage inserted into the E. coli material of the F' factor. Improper prophage excision can then lead to formation of P22 specialized phages carrying E. coli genetic material. PMID:4599252

  9. A bioinformatic analysis of ribonucleotide reductase genes in phage genomes and metagenomes

    PubMed Central

    2013-01-01

    Background Ribonucleotide reductase (RNR), the enzyme responsible for the formation of deoxyribonucleotides from ribonucleotides, is found in all domains of life and many viral genomes. RNRs are also amongst the most abundant genes identified in environmental metagenomes. This study focused on understanding the distribution, diversity, and evolution of RNRs in phages (viruses that infect bacteria). Hidden Markov Model profiles were used to analyze the proteins encoded by 685 completely sequenced double-stranded DNA phages and 22 environmental viral metagenomes to identify RNR homologs in cultured phages and uncultured viral communities, respectively. Results RNRs were identified in 128 phage genomes, nearly tripling the number of phages known to encode RNRs. Class I RNR was the most common RNR class observed in phages (70%), followed by class II (29%) and class III (28%). Twenty-eight percent of the phages contained genes belonging to multiple RNR classes. RNR class distribution varied according to phage type, isolation environment, and the host’s ability to utilize oxygen. The majority of the phages containing RNRs are Myoviridae (65%), followed by Siphoviridae (30%) and Podoviridae (3%). The phylogeny and genomic organization of phage and host RNRs reveal several distinct evolutionary scenarios involving horizontal gene transfer, co-evolution, and differential selection pressure. Several putative split RNR genes interrupted by self-splicing introns or inteins were identified, providing further evidence for the role of frequent genetic exchange. Finally, viral metagenomic data indicate that RNRs are prevalent and highly dynamic in uncultured viral communities, necessitating future research to determine the environmental conditions under which RNRs provide a selective advantage. Conclusions This comprehensive study describes the distribution, diversity, and evolution of RNRs in phage genomes and environmental viral metagenomes. The distinct distributions of

  10. Isolation and Characterization of Five Erwinia amylovora Bacteriophages and Assessment of Phage Resistance in Strains of Erwinia amylovora

    PubMed Central

    Schnabel, Elise L.; Jones, Alan L.

    2001-01-01

    Phages able to infect the fire blight pathogen Erwinia amylovora were isolated from apple, pear, and raspberry tissues and from soil samples collected at sites displaying fire blight symptoms. Among a collection of 50 phage isolates, 5 distinct phages, including relatives of the previously described phages φEa1 and φEa7 and 3 novel phages named φEa100, φEa125, and φEa116C, were identified based on differences in genome size and restriction fragment pattern. φEa1, the phage distributed most widely, had an approximately 46-kb genome which exhibited some restriction site variability between isolates. Phages φEa100, φEa7, and φEa125 each had genomes of approximately 35 kb and could be distinguished by their EcoRI restriction fragment patterns. φEa116C contained an approximately 75-kb genome. φEa1, φEa7, φEa100, φEa125, and φEa116C were able to infect 39, 36, 16, 20, and 40, respectively, of 40 E. amylovora strains isolated from apple orchards in Michigan and 8, 12, 10, 10, and 12, respectively, of 12 E. amylovora strains isolated from raspberry fields (Rubus spp.) in Michigan. Only 22 of 52 strains were sensitive to all five phages, and 23 strains exhibited resistance to more than one phage. φEa116C was more effective than the other phages at lysing E. amylovora strain Ea110 in liquid culture, reducing the final titer of Ea110 by >95% when added at a ratio of 1 PFU per 10 CFU and by 58 to 90% at 1 PFU per 105 CFU. PMID:11133428

  11. Characterization of novel virulent broad-host-range phages of Xylella fastidiosa and Xanthomonas.

    PubMed

    Ahern, Stephen J; Das, Mayukh; Bhowmick, Tushar Suvra; Young, Ry; Gonzalez, Carlos F

    2014-01-01

    The xylem-limited bacterium Xylella fastidiosa is the causal agent of several plant diseases, most notably Pierce's disease of grape and citrus variegated chlorosis. We report the isolation and characterization of the first virulent phages for X. fastidiosa, siphophages Sano and Salvo and podophages Prado and Paz, with a host range that includes Xanthomonas spp. Phages propagated on homologous hosts had observed adsorption rate constants of ~4 × 10(-12) ml cell(-1) min(-1) for X. fastidiosa strain Temecula 1 and ~5 × 10(-10) to 7 × 10(-10) ml cell(-1) min(-1) for Xanthomonas strain EC-12. Sano and Salvo exhibit >80% nucleotide identity to each other in aligned regions and are syntenic to phage BcepNazgul. We propose that phage BcepNazgul is the founding member of a novel phage type, to which Sano and Salvo belong. The lysis genes of the Nazgul-like phage type include a gene that encodes an outer membrane lipoprotein endolysin and also spanin gene families that provide insight into the evolution of the lysis pathway for phages of Gram-negative hosts. Prado and Paz, although exhibiting no significant DNA homology to each other, are new members of the phiKMV-like phage type, based on the position of the single-subunit RNA polymerase gene. The four phages are type IV pilus dependent for infection of both X. fastidiosa and Xanthomonas. The phages may be useful as agents for an effective and environmentally responsible strategy for the control of diseases caused by X. fastidiosa.

  12. Characterization of Novel Virulent Broad-Host-Range Phages of Xylella fastidiosa and Xanthomonas

    PubMed Central

    Ahern, Stephen J.; Das, Mayukh; Bhowmick, Tushar Suvra; Young, Ry

    2014-01-01

    The xylem-limited bacterium Xylella fastidiosa is the causal agent of several plant diseases, most notably Pierce's disease of grape and citrus variegated chlorosis. We report the isolation and characterization of the first virulent phages for X. fastidiosa, siphophages Sano and Salvo and podophages Prado and Paz, with a host range that includes Xanthomonas spp. Phages propagated on homologous hosts had observed adsorption rate constants of ∼4 × 10−12 ml cell−1 min−1 for X. fastidiosa strain Temecula 1 and ∼5 × 10−10 to 7 × 10−10 ml cell−1 min−1 for Xanthomonas strain EC-12. Sano and Salvo exhibit >80% nucleotide identity to each other in aligned regions and are syntenic to phage BcepNazgul. We propose that phage BcepNazgul is the founding member of a novel phage type, to which Sano and Salvo belong. The lysis genes of the Nazgul-like phage type include a gene that encodes an outer membrane lipoprotein endolysin and also spanin gene families that provide insight into the evolution of the lysis pathway for phages of Gram-negative hosts. Prado and Paz, although exhibiting no significant DNA homology to each other, are new members of the phiKMV-like phage type, based on the position of the single-subunit RNA polymerase gene. The four phages are type IV pilus dependent for infection of both X. fastidiosa and Xanthomonas. The phages may be useful as agents for an effective and environmentally responsible strategy for the control of diseases caused by X. fastidiosa. PMID:24214944

  13. Genetically Engineered Virulent Phage Banks in the Detection and Control of Emergent Pathogenic Bacteria

    PubMed Central

    Blois, Hélène; Iris, François

    2010-01-01

    Natural outbreaks of multidrug-resistant microorganisms can cause widespread devastation, and several can be used or engineered as agents of bioterrorism. From a biosecurity standpoint, the capacity to detect and then efficiently control, within hours, the spread and the potential pathological effects of an emergent outbreak, for which there may be no effective antibiotics or vaccines, become key challenges that must be met. We turned to phage engineering as a potentially highly flexible and effective means to both detect and eradicate threats originating from emergent (uncharacterized) bacterial strains. To this end, we developed technologies allowing us to (1) concurrently modify multiple regions within the coding sequence of a gene while conserving intact the remainder of the gene, (2) reversibly interrupt the lytic cycle of an obligate virulent phage (T4) within its host, (3) carry out efficient insertion, by homologous recombination, of any number of engineered genes into the deactivated genomes of a T4 wild-type phage population, and (4) reactivate the lytic cycle, leading to the production of engineered infective virulent recombinant progeny. This allows the production of very large, genetically engineered lytic phage banks containing, in an E. coli host, a very wide spectrum of variants for any chosen phage-associated function, including phage host-range. Screening of such a bank should allow the rapid isolation of recombinant T4 particles capable of detecting (ie, diagnosing), infecting, and destroying hosts belonging to gram-negative bacterial species far removed from the original E. coli host. PMID:20569057

  14. Analysis of whole genome sequencing for the Escherichia coli O157:H7 typing phages.

    PubMed

    Cowley, Lauren A; Beckett, Stephen J; Chase-Topping, Margo; Perry, Neil; Dallman, Tim J; Gally, David L; Jenkins, Claire

    2015-04-08

    Shiga toxin producing Escherichia coli O157 can cause severe bloody diarrhea and haemolytic uraemic syndrome. Phage typing of E. coli O157 facilitates public health surveillance and outbreak investigations, certain phage types are more likely to occupy specific niches and are associated with specific age groups and disease severity. The aim of this study was to analyse the genome sequences of 16 (fourteen T4 and two T7) E. coli O157 typing phages and to determine the genes responsible for the subtle differences in phage type profiles. The typing phages were sequenced using paired-end Illumina sequencing at The Genome Analysis Centre and the Animal Health and Veterinary Laboratories Agency and bioinformatics programs including Velvet, Brig and Easyfig were used to analyse them. A two-way Euclidian cluster analysis highlighted the associations between groups of phage types and typing phages. The analysis showed that the T7 typing phages (9 and 10) differed by only three genes and that the T4 typing phages formed three distinct groups of similar genomic sequences: Group 1 (1, 8, 11, 12 and 15, 16), Group 2 (3, 6, 7 and 13) and Group 3 (2, 4, 5 and 14). The E. coli O157 phage typing scheme exhibited a significantly modular network linked to the genetic similarity of each group showing that these groups are specialised to infect a subset of phage types. Sequencing the typing phage has enabled us to identify the variable genes within each group and to determine how this corresponds to changes in phage type.

  15. Phage wrapping with cationic polymers eliminates nonspecific binding between M13 phage and high pI target proteins.

    PubMed

    Lamboy, Jorge A; Arter, Jessica A; Knopp, Kristeene A; Der, Denise; Overstreet, Cathie M; Palermo, Edmund F; Urakami, Hiromitsu; Yu, Ting-Bin; Tezgel, Ozgul; Tew, Gregory N; Guan, Zhibin; Kuroda, Kenichi; Weiss, Gregory A

    2009-11-18

    M13 phage have provided scaffolds for nanostructure synthesis based upon self-assembled inorganic and hard materials interacting with phage-displayed peptides. Additionally, phage display has been used to identify binders to plastic, TiO(2), and other surfaces. However, synthesis of phage-based materials through the hybridization of soft materials with the phage surface remains unexplored. Here, we present an efficient "phage wrapping" strategy for the facile synthesis of phage coated with soluble, cationic polymers. Polymers bearing high positive charge densities demonstrated the most effective phage wrapping, as shown by assays for blocking nonspecific binding of the anionic phage coat to a high pI target protein. The results establish the functional group requirements for hybridizing phage with soft materials and solve a major problem in phage display-nonspecific binding by the phage to high pI target proteins.

  16. Archaeal Viruses, Not Archaeal Phages: An Archaeological Dig

    PubMed Central

    Abedon, Stephen T.; Murray, Kelly L.

    2013-01-01

    Viruses infect members of domains Bacteria, Eukarya, and Archaea. While those infecting domain Eukarya are nearly universally described as “Viruses”, those of domain Bacteria, to a substantial extent, instead are called “Bacteriophages,” or “Phages.” Should the viruses of domain Archaea therefore be dubbed “Archaeal phages,” “Archaeal viruses,” or some other construct? Here we provide documentation of published, general descriptors of the viruses of domain Archaea. Though at first the term “Phage” or equivalent was used almost exclusively in the archaeal virus literature, there has been a nearly 30-year trend away from this usage, with some persistence of “Phage” to describe “Head-and-tail” archaeal viruses, “Halophage” to describe viruses of halophilic Archaea, use of “Prophage” rather than “Provirus,” and so forth. We speculate on the root of the early 1980's transition from “Phage” to “Virus” to describe these infectious agents, consider the timing of introduction of “Archaeal virus” (which can be viewed as analogous to “Bacterial virus”), identify numerous proposed alternatives to “Archaeal virus,” and also provide discussion of the general merits of the term, “Phage.” Altogether we identify in excess of one dozen variations on how the viruses of domain Archaea are described, and document the timing of both their introduction and use. PMID:23653528

  17. Genomic characterization of Ralstonia solanacearum phage phiRSB1, a T7-like wide-host-range phage.

    PubMed

    Kawasaki, Takeru; Shimizu, Mio; Satsuma, Hideki; Fujiwara, Akiko; Fujie, Makoto; Usami, Shoji; Yamada, Takashi

    2009-01-01

    PhiRSB1 is a wide-host-range, T7-like bacteriophage that infects and efficiently lyses the phytopathogenic bacterium Ralstonia solanacearum. The phiRSB1 genome comprises 43,079 bp of double-stranded DNA (61.7% G+C) with 325-bp terminal repeats and contains 47 open reading frames. Strong activity of tandem early promoters and wide specificity of phage promoters of phiRSB1 were demonstrated.

  18. Phage Therapy: Beyond Antibacterial Action.

    PubMed

    Górski, Andrzej; Jończyk-Matysiak, Ewa; Międzybrodzki, Ryszard; Weber-Dąbrowska, Beata; Łusiak-Szelachowska, Marzanna; Bagińska, Natalia; Borysowski, Jan; Łobocka, Małgorzata B; Węgrzyn, Alicja; Węgrzyn, Grzegorz

    2018-01-01

    Until recently, phages were considered as mere "bacteria eaters" with potential for use in combating antimicrobial resistance. The real value of phage therapy assessed according to the standards of evidence-based medicine awaits confirmation by clinical trials. However, the progress in research on phage biology has shed more light on the significance of phages. Accumulating data indicate that phages may also interact with eukaryotic cells. How such interactions could be translated into advances in medicine (especially novel means of therapy) is discussed herein.

  19. Safety analysis of a Russian phage cocktail: From MetaGenomic analysis to oral application in healthy human subjects

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McCallin, Shawna, E-mail: semccallin@yahoo.com; Alam Sarker, Shafiqul, E-mail: sasarker@icddrb.org; Barretto, Caroline, E-mail: Caroline.Barretto@rdls.nestle.com

    Phage therapy has a long tradition in Eastern Europe, where preparations are comprised of complex phage cocktails whose compositions have not been described. We investigated the composition of a phage cocktail from the Russian pharmaceutical company Microgen targeting Escherichia coli/Proteus infections. Electron microscopy identified six phage types, with numerically T7-like phages dominating over T4-like phages. A metagenomic approach using taxonomical classification, reference mapping and de novo assembly identified 18 distinct phage types, including 7 genera of Podoviridae, 2 established and 2 proposed genera of Myoviridae, and 2 genera of Siphoviridae. De novo assembly yielded 7 contigs greater than 30 kb,more » including a 147-kb Myovirus genome and a 42-kb genome of a potentially new phage. Bioinformatic analysis did not reveal undesired genes and a small human volunteer trial did not associate adverse effects with oral phage exposure. - Highlights: • We analyzed the composition of a commercial Russian phage cocktail. • The cocktail consists of at least 10 different phage genera. • No undesired genes were detected. • No adverse effects were seen upon oral application in a small human clinical trial.« less

  20. Biocontrol of Listeria monocytogenes and Escherichia coli O157:H7 in Meat by Using Phages Immobilized on Modified Cellulose Membranes ▿

    PubMed Central

    Anany, H.; Chen, W.; Pelton, R.; Griffiths, M. W.

    2011-01-01

    The ability of phages to specifically interact with and lyse their host bacteria makes them ideal antibacterial agents. The range of applications of bacteriophage can be extended by their immobilization on inert surfaces. A novel method for the oriented immobilization of bacteriophage has been developed. The method was based on charge differences between the bacteriophage head, which exhibits an overall net negative charge, and the tail fibers, which possess an overall net positive charge. Hence, the head would be more likely to attach to positively charged surfaces, leaving the tails free to capture and lyse bacteria. Cellulose membranes modified so that they had a positive surface charge were used as the support for phage immobilization. It was established that the number of infective phages immobilized on the positively charged cellulose membranes was significantly higher than that on unmodified membranes. Cocktails of phages active against Listeria or Escherichia coli immobilized on these membranes were shown to effectively control the growth of L. monocytogenes and E. coli O157:H7 in ready-to-eat and raw meat, respectively, under different storage temperatures and packaging conditions. The phage storage stability was investigated to further extend their industrial applications. It was shown that lyophilization can be used as a phage-drying method to maintain their infectivity on the newly developed bioactive materials. In conclusion, utilizing the charge difference between phage heads and tails provided a simple technique for oriented immobilization applicable to a wide range of phages and allowed the retention of infectivity. PMID:21803890

  1. Bacteriophage Infecting the Myxobacterium Chondrococcus columnaris

    PubMed Central

    Kingsbury, David T.; Ordal, Erling J.

    1966-01-01

    Kingsbury, David T. (University of Washington, Seattle), and Erling J. Ordal. Bacteriophage infecting the myxobacterium Chondrococcus columnaris. J. Bacteriol. 91:1327–1332. 1966.—During a series of screening experiments, seven bacteriophages which infect the pathogenic myxobacterium Chondrococcus columnaris were isolated. Of these, one was chosen for detailed study. This phage has a wide host range among strains of C. columnaris, but does not infect other myxobacterial species tested. Morphologically, this phage resembles coliphage T2, though it is smaller. It has a head diameter of 600 A, a tail length of 1,000 A, and a tail width of 200 A. The head is attached to the tail by a well-defined neck. The turbid plaques produced by this phage are similar in appearance to those produced by coliphage λ, and average 1 mm in diameter. The phage has a latent period of 100 min, a rise period of an additional 90 min, and a burst size of 23. Calcium ions at a concentration of 0.004 m are required for adsorption. This requirement cannot be met by substitution of magnesium ions. A purified preparation of 2 × 1012 phage particles was extracted with phenol, and the nucleic acid was identified as deoxyribonucleic acid (DNA). Base ratios of the phage DNA and the DNA of two propagating strains were similar. Streptomycin at a concentration of 70 μg/ml inhibits phage infection at an early stage, probably by inhibiting injection of the phage DNA. Images PMID:5929758

  2. Efficacy of potential phage cocktails against Vibrio harveyi and closely related Vibrio species isolated from shrimp aquaculture environment in the south east coast of India.

    PubMed

    Stalin, Nattan; Srinivasan, Pappu

    2017-08-01

    A diverse set of novel phages infecting the marine pathogenic Vibrio harveyi was isolated from shrimp aquaculture environments in the south east coast of India. Based on initial screening, three phages with a broad host range revealed that the growth inhibition of phage is relatively specific to V. harveyi. They were also able to infect V. alginolyticus and V. parahemolyticus that belonged to the Harveyi clade species from shrimp pond and sea coast environment samples. However, the impact of these phages on their host bacterium are well understood; a one-step growth curve experiment and transmission electron microscope (TEM) revealed three phages grouped under the Myoviridae (VHM1 and VHM2); Siphoviridae (VHS1) family. These phages were further molecular characterized with respect to phage genomic DNA isolates. The randomly amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) digestion with HindIII, and major structural proteins were distinguished by sodium-dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) clearly indicated that all the phage isolates were different, even when they came from the same source, giving an insight into the diversity of phages. Evaluation of microcosm studies of Penaeus monodon larvae infected with V. harveyi (105 CFU mL-1) showed that larvae survival after 96 h in the presence of phage treatment at 109 PFU mL-1 was enhanced when compared with the control. The resolution in over survival highly recommended that this study provides the phage-based therapy which could be an innovative and eco-friendly solution against Vibrio disease in shrimp aquaculture and in the natural environment. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Host-pathogen interactions and bacterial survival under phage fluctuations

    NASA Astrophysics Data System (ADS)

    Skanata, Antun; Kussell, Edo

    Environmental changes can have profound effects on ecosystems, leading to drastic outcomes such as extinction and desertification. Quantifying, predicting, and ultimately preventing those transitions is a key problem in the field. Our previous work in microbial systems has shown that fluctuations in environments drive transitions to alternate evolutionary optima, which can be either smooth or abrupt. The long term growth rate, an analog of free energy for population dynamics, has been used to distinguish under what conditions those transitions will occur. Our framework, which uses the mean field approximation to compute the long term growth rate in fluctuating environments, is uniquely positioned to treat more complex dependencies that allow coexistence among species sharing resources or infected by common pathogens. Here we present a simple model of a bacterial community subjected to fluctuating phage infections that outlines the regimes where species diversity results in long-term stability. We identify prevalent, but often counter-intuitive, strategies that bacteria use to protect against infection, and find a new general principle in the evolution of phage resistance. Our results, which predict the transition regimes, have implications for a broad range of ecological models.

  4. Vibrio Phage KVP40 Encodes a Functional NAD+ Salvage Pathway.

    PubMed

    Lee, Jae Yun; Li, Zhiqun; Miller, Eric S

    2017-05-01

    + for ADP-ribosylation of proteins involved in transcribing and translating the phage genome. We show here that phage KVP40 encodes a functional pyridine nucleotide scavenging pathway that is expressed during the metabolic period of the infection cycle. The pathway is conserved in other large, dsDNA phages in which the two genes, nadV and natV , share an evolutionary history in their respective phage-host group. Copyright © 2017 American Society for Microbiology.

  5. Abortion at Gondar College Hospital, Ethiopia.

    PubMed

    Yusuf, L; Zein, Z A

    2001-05-01

    To review the pattern and magnitude of abortion in order to establish baseline facts and data for future studies. A descriptive cross-sectional study. Gondar College of Medical Sciences Hospital, Gondar, Ethiopia. Most of the subjects originated from the Gondar city and were married housewives, parous and relatively young. The abortion rate and ratio per 100 pregnancies and deliveries were 11.5 and 16.4, respectively. Only 13.4% of the patients admitted history of interference with the pregnancy. Previous history of abortion was obtained in 10.6% of the patients. The mean gestational ages for septic and non-septic cases were 14.6 and 15.2 weeks, respectively even though pregnancies less than 12 weeks from the last normal menstrual period accounted for 50.5%. The commonly diagnosed clinical type was incomplete, followed by inevitable and threatened abortion. The vast majority of the clinical conditions were non-septic (85.1 %) and spontaneous(85.6 %). The most common complications registered were anaemia, genital tract infection, shock of various causes and soft tissue injury. Four mothers died of abortion-related complications. The mean hospital stays for non-septic and septic abortion were three and five days, respectively. The study has attempted to address the issue of abortion in its general clinical pattern in relation to the various parameters. Being comprehensive, it also provides awareness and sensitivity on the magnitude of abortion and is assumed quite helpful for policy and decision makers.

  6. Emerging methods to study bacteriophage infection at the single-cell level.

    PubMed

    Dang, Vinh T; Sullivan, Matthew B

    2014-01-01

    Bacteria and their viruses (phages) are abundant across diverse ecosystems and their interactions influence global biogeochemical cycles and incidence of disease. Problematically, both classical and metagenomic methods insufficiently assess the host specificity of phages and phage-host infection dynamics in nature. Here we review emerging methods to study phage-host interaction and infection dynamics with a focus on those that offer resolution at the single-cell level. These methods leverage ever-increasing sequence data to identify virus signals from single-cell amplified genome datasets or to produce primers/probes to target particular phage-bacteria pairs (digital PCR and phageFISH), even in complex communities. All three methods enable study of phage infection of uncultured bacteria from environmental samples, while the latter also discriminates between phage-host interaction outcomes (e.g., lytic, chronic, lysogenic) in model systems. Together these techniques enable quantitative, spatiotemporal studies of phage-bacteria interactions from environmental samples of any ecosystem, which will help elucidate and predict the ecological and evolutionary impacts of specific phage-host pairings in nature.

  7. Whole genome comparison of a large collection of mycobacteriophages reveals a continuum of phage genetic diversity

    PubMed Central

    Pope, Welkin H; Bowman, Charles A; Russell, Daniel A; Jacobs-Sera, Deborah; Asai, David J; Cresawn, Steven G; Jacobs, William R; Hendrix, Roger W; Lawrence, Jeffrey G; Hatfull, Graham F; Abbazia, Patrick; Ababio, Amma; Adam, Naazneen

    2015-01-01

    The bacteriophage population is large, dynamic, ancient, and genetically diverse. Limited genomic information shows that phage genomes are mosaic, and the genetic architecture of phage populations remains ill-defined. To understand the population structure of phages infecting a single host strain, we isolated, sequenced, and compared 627 phages of Mycobacterium smegmatis. Their genetic diversity is considerable, and there are 28 distinct genomic types (clusters) with related nucleotide sequences. However, amino acid sequence comparisons show pervasive genomic mosaicism, and quantification of inter-cluster and intra-cluster relatedness reveals a continuum of genetic diversity, albeit with uneven representation of different phages. Furthermore, rarefaction analysis shows that the mycobacteriophage population is not closed, and there is a constant influx of genes from other sources. Phage isolation and analysis was performed by a large consortium of academic institutions, illustrating the substantial benefits of a disseminated, structured program involving large numbers of freshman undergraduates in scientific discovery. DOI: http://dx.doi.org/10.7554/eLife.06416.001 PMID:25919952

  8. Whole genome comparison of a large collection of mycobacteriophages reveals a continuum of phage genetic diversity.

    PubMed

    Pope, Welkin H; Bowman, Charles A; Russell, Daniel A; Jacobs-Sera, Deborah; Asai, David J; Cresawn, Steven G; Jacobs, William R; Hendrix, Roger W; Lawrence, Jeffrey G; Hatfull, Graham F

    2015-04-28

    The bacteriophage population is large, dynamic, ancient, and genetically diverse. Limited genomic information shows that phage genomes are mosaic, and the genetic architecture of phage populations remains ill-defined. To understand the population structure of phages infecting a single host strain, we isolated, sequenced, and compared 627 phages of Mycobacterium smegmatis. Their genetic diversity is considerable, and there are 28 distinct genomic types (clusters) with related nucleotide sequences. However, amino acid sequence comparisons show pervasive genomic mosaicism, and quantification of inter-cluster and intra-cluster relatedness reveals a continuum of genetic diversity, albeit with uneven representation of different phages. Furthermore, rarefaction analysis shows that the mycobacteriophage population is not closed, and there is a constant influx of genes from other sources. Phage isolation and analysis was performed by a large consortium of academic institutions, illustrating the substantial benefits of a disseminated, structured program involving large numbers of freshman undergraduates in scientific discovery.

  9. A review of evidence for safe abortion care.

    PubMed

    Kapp, Nathalie; Whyte, Patti; Tang, Jennifer; Jackson, Emily; Brahmi, Dalia

    2013-09-01

    The provision of safe abortion services to women who need them has the potential to drastically reduce or eliminate maternal deaths due to unsafe abortion. The World Health Organization recently updated its evidence-based guidance for safe and effective clinical practices using data from systematic reviews of the literature. Systematic reviews pertaining to the evidence for safe abortion services, from pre-abortion care, medical and surgical methods of abortion and post-abortion care were evaluated for relevant outcomes, primarily those relating to safety, effectiveness and women's preference. Sixteen systematic reviews were identified and evaluated. The available evidence does not support the use of pre-abortion ultrasound to increase safety. Routine use of cervical preparation with osmotic dilators, mifepristone or misoprostol after 14 weeks gestation reduces complications; at early gestational ages, surgical abortions have very few complications. Prophylactic antibiotics result in lower rates of post-surgical abortion infection. Pain medication such as non-steroidal anti-inflammatories should be offered to women undergoing abortion procedures; acetaminophen, however, is not effective in reducing pain. Women who are eligible should be offered a choice between surgical (vacuum aspiration or dilation and evacuation) and medical methods (mifepristone and misoprostol) of abortion when possible. Modern methods of contraception can be safely initiated immediately following abortion procedures. Evidence-based guidelines assist health care providers and policymakers to utilize the best data available to provide safe abortion care and prevent the millions of deaths and disabilities that result from unsafe abortion. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Effects of Abortion Legalization in Nepal, 2001–2010

    PubMed Central

    Henderson, Jillian T.; Puri, Mahesh; Blum, Maya; Harper, Cynthia C.; Rana, Ashma; Gurung, Geeta; Pradhan, Neelam; Regmi, Kiran; Malla, Kasturi; Sharma, Sudha; Grossman, Daniel; Bajracharya, Lata; Satyal, Indira; Acharya, Shridhar; Lamichhane, Prabhat; Darney, Philip D.

    2013-01-01

    Background Abortion was legalized in Nepal in 2002, following advocacy efforts highlighting high maternal mortality from unsafe abortion. We sought to assess whether legalization led to reductions in the most serious maternal health consequences of unsafe abortion. Methods We conducted retrospective medical chart review of all gynecological cases presenting at four large public referral hospitals in Nepal. For the years 2001–2010, all cases of spontaneous and induced abortion complications were identified, abstracted, and coded to classify cases of serious infection, injury, and systemic complications. We used segmented Poisson and ordinary logistic regression to test for trend and risks of serious complications for three time periods: before implementation (2001–2003), early implementation (2004–2006), and later implementation (2007–2010). Results 23,493 cases of abortion complications were identified. A significant downward trend in the proportion of serious infection, injury, and systemic complications was observed for the later implementation period, along with a decline in the risk of serious complications (OR 0.7, 95% CI 0.64, 0.85). Reductions in sepsis occurred sooner, during early implementation (OR 0.6, 95% CI 0.47, 0.75). Conclusion Over the study period, health care use and the population of reproductive aged women increased. Total fertility also declined by nearly half, despite relatively low contraceptive prevalence. Greater numbers of women likely obtained abortions and sought hospital care for complications following legalization, yet we observed a significant decline in the rate of serious abortion morbidity. The liberalization of abortion policy in Nepal has benefited women’s health, and likely contributes to falling maternal mortality in the country. The steepest decline was observed after expansion of the safe abortion program to include midlevel providers, second trimester training, and medication abortion, highlighting the importance

  11. Antibody Production in Response to Staphylococcal MS-1 Phage Cocktail in Patients Undergoing Phage Therapy.

    PubMed

    Żaczek, Maciej; Łusiak-Szelachowska, Marzanna; Jończyk-Matysiak, Ewa; Weber-Dąbrowska, Beata; Międzybrodzki, Ryszard; Owczarek, Barbara; Kopciuch, Agnieszka; Fortuna, Wojciech; Rogóż, Paweł; Górski, Andrzej

    2016-01-01

    In this study, we investigated the humoral immune response (through the release of IgG, IgA, and IgM antiphage antibodies) to a staphylococcal phage cocktail in patients undergoing experimental phage therapy at the Phage Therapy Unit, Medical Center of the Ludwik Hirszfeld Institute of Immunology and Experimental Therapy in Wrocław, Poland. We also evaluated whether occurring antiphage antibodies had neutralizing properties toward applied phages (K rate). Among 20 examined patients receiving the MS-1 phage cocktail orally and/or locally, the majority did not show a noticeably higher level of antiphage antibodies in their sera during phage administration. Even in those individual cases with an increased immune response, mostly by induction of IgG and IgM, the presence of antiphage antibodies did not translate into unsatisfactory clinical results of phage therapy. On the other hand, a negative outcome of the treatment occurred in some patients who showed relatively weak production of antiphage antibodies before and during treatment. This may imply that possible induction of antiphage antibodies is not an obstacle to the implementation of phage therapy and support our assumption that the outcome of the phage treatment does not primarily depend on the appearance of antiphage antibodies in sera of patients during therapy. These conclusions are in line with our previous findings. The confirmation of this thesis is of great interest as regards the efficacy of phage therapy in humans.

  12. The role of the T7 Gp2 inhibitor of host RNA polymerase in phage development.

    PubMed

    Savalia, Dhruti; Robins, William; Nechaev, Sergei; Molineux, Ian; Severinov, Konstantin

    2010-09-10

    Bacteriophage T7 relies on its own RNA polymerase (RNAp) to transcribe its middle and late genes. Early genes, which include the viral RNAp gene, are transcribed by the host RNAp from three closely spaced strong promoters-A1, A2, and A3. One middle T7 gene product, gp2, is a strong inhibitor of the host RNAp. Gp2 is essential and is required late in infection, during phage DNA packaging. Here, we explore the role of gp2 in controlling host RNAp transcription during T7 infection. We demonstrate that in the absence of gp2, early viral transcripts continue to accumulate throughout the infection. Decreasing transcription from early promoter A3 is sufficient to make gp2 dispensable for phage infection. Gp2 also becomes dispensable when an antiterminating element boxA, located downstream of early promoters, is deleted. The results thus suggest that antiterminated transcription by host RNAp from the A3 promoter is interfering with phage development and that the only essential role for gp2 is to prevent this transcription. Copyright 2010 Elsevier Ltd. All rights reserved.

  13. Receptor Diversity and Host Interaction of Bacteriophages Infecting Salmonella enterica Serovar Typhimurium

    PubMed Central

    Kim, Hyeryen; Choi, Younho; Heu, Sunggi; Ryu, Sangryeol

    2012-01-01

    Background Salmonella enterica subspecies enterica serovar Typhimurium is a Gram-negative pathogen causing salmonellosis. Salmonella Typhimurium-targeting bacteriophages have been proposed as an alternative biocontrol agent to antibiotics. To further understand infection and interaction mechanisms between the host strains and the bacteriophages, the receptor diversity of these phages needs to be elucidated. Methodology/Principal Findings Twenty-five Salmonella phages were isolated and their receptors were identified by screening a Tn5 random mutant library of S. Typhimurium SL1344. Among them, three types of receptors were identified flagella (11 phages), vitamin B12 uptake outer membrane protein, BtuB (7 phages) and lipopolysaccharide-related O-antigen (7 phages). TEM observation revealed that the phages using flagella (group F) or BtuB (group B) as a receptor belong to Siphoviridae family, and the phages using O-antigen of LPS as a receptor (group L) belong to Podoviridae family. Interestingly, while some of group F phages (F-I) target FliC host receptor, others (F-II) target both FliC and FljB receptors, suggesting that two subgroups are present in group F phages. Cross-resistance assay of group B and L revealed that group L phages could not infect group B phage-resistant strains and reversely group B phages could not infect group L SPN9TCW-resistant strain. Conclusions/Significance In this report, three receptor groups of 25 newly isolated S. Typhimurium-targeting phages were determined. Among them, two subgroups of group F phages interact with their host receptors in different manner. In addition, the host receptors of group B or group L SPN9TCW phages hinder other group phage infection, probably due to interaction between receptors of their groups. This study provides novel insights into phage-host receptor interaction for Salmonella phages and will inform development of optimal phage therapy for protection against Salmonella. PMID:22927964

  14. Free Shiga toxin 1-encoding bacteriophages are less prevalent than Shiga toxin 2 phages in extraintestinal environments.

    PubMed

    Grau-Leal, Ferran; Quirós, Pablo; Martínez-Castillo, Alexandre; Muniesa, Maite

    2015-11-01

    Stx bacteriophages are involved in the pathogenicity of Stx-producing Escherichia coli. Induction of the Stx phage lytic cycle increases Stx expression and releases Stx phages that reach extracellular environments. Stx phage family comprises different phages that harbour any stx subtype. Stx2 is closely related with severe disease and therefore previous studies focused on free Stx2 phages in extraintestinal environments. To provide similar information regarding Stx1 phages, we evaluate free Stx1 phages in 357 samples of human and animal wastewater, faeces, river water, soil, sludge and food. Our method, based on quantification of stx1 in the DNA from the viral fraction, was validated using electron microscopy counting of phages and infectivity. The overall prevalence of Stx1 phages was very low: 7.6% of positive samples and values below 3 × 10(3) GC (gene copies) ml(-1) . These results contrast starkly with the abundance of Stx2 phages in the samples (68.4%). This environmental scarcity of free Stx1 phages is attributed to their lower rates of induction and the fact that Stx1 does not require phage induction to be expressed because it possesses an independent promoter. The implications of the low prevalence of free Stx1 phages for the emergence of new pathogenic strains in the environment are discussed. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Phage Wrapping with Cationic Polymers Eliminates Non-specific Binding between M13 Phage and High pI Target Proteins

    PubMed Central

    Lamboy, Jorge A.; Arter, Jessica A.; Knopp, Kristeene A.; Der, Denise; Overstreet, Cathie M.; Palermo, Edmund; Urakami, Hiromitsu; Yu, Ting-Bin; Tezgel, Ozgul; Tew, Gregory; Guan, Zhibin; Kuroda, Kenichi; Weiss, Gregory A.

    2011-01-01

    M13 phage have provided scaffolds for nanostructure synthesis based upon self-assembled inorganic and hard materials interacting with phage-displayed peptides. Additionally, phage display has been used to identify binders to plastic, TiO2, and other surfaces. However, synthesis of phage-based materials through the hybridization of soft materials with the phage surface remains unexplored. Here, we present an efficient “phage wrapping” strategy for the facile synthesis of phage coated with soluble, cationic polymers. Polymers bearing high positive charge densities demonstrated the most effective phage wrapping, as shown by assays for blocking non-specific binding of the anionic phage coat to a high pI target protein. The results establish the functional group requirements for hybridizing phage with soft materials, and solve a major problem in phage display – non-specific binding by the phage to high pI target proteins. PMID:19856910

  16. Novel Variants of Streptococcus thermophilus Bacteriophages Are Indicative of Genetic Recombination among Phages from Different Bacterial Species

    PubMed Central

    Szymczak, Paula; Neves, Ana Rute; Kot, Witold; Hansen, Lars H.; Lametsch, René; Neve, Horst; Franz, Charles M. A. P.

    2016-01-01

    ABSTRACT Bacteriophages are the main cause of fermentation failures in dairy plants. The majority of Streptococcus thermophilus phages can be divided into either cos- or pac-type phages and are additionally characterized by examining the V2 region of their antireceptors. We screened a large number of S. thermophilus phages from the Chr. Hansen A/S collection, using PCR specific for the cos- or pac-type phages, as well as for the V2 antireceptor region. Three phages did not produce positive results with the assays. Analysis of phage morphologies indicated that two of these phages, CHPC577 and CHPC926, had shorter tails than the traditional S. thermophilus phages. The third phage, CHPC1151, had a tail size similar to those of the cos- or pac-type phages, but it displayed a different baseplate structure. Sequencing analysis revealed the genetic similarity of CHPC577 and CHPC926 with a subgroup of Lactococcus lactis P335 phages. Phage CHPC1151 was closely related to the atypical S. thermophilus phage 5093, homologous with a nondairy streptococcal prophage. By testing adsorption of the related streptococcal and lactococcal phages to the surface of S. thermophilus and L. lactis strains, we revealed the possibility of cross-interactions. Our data indicated that the use of S. thermophilus together with L. lactis, extensively applied for dairy fermentations, triggered the recombination between phages infecting different bacterial species. A notable diversity among S. thermophilus phage populations requires that a new classification of the group be proposed. IMPORTANCE Streptococcus thermophilus is a component of thermophilic starter cultures commonly used for cheese and yogurt production. Characterizing streptococcal phages, understanding their genetic relationships, and studying their interactions with various hosts are the necessary steps for preventing and controlling phage attacks that occur during dairy fermentations. PMID:28039135

  17. Novel Variants of Streptococcus thermophilus Bacteriophages Are Indicative of Genetic Recombination among Phages from Different Bacterial Species.

    PubMed

    Szymczak, Paula; Janzen, Thomas; Neves, Ana Rute; Kot, Witold; Hansen, Lars H; Lametsch, René; Neve, Horst; Franz, Charles M A P; Vogensen, Finn K

    2017-03-01

    Bacteriophages are the main cause of fermentation failures in dairy plants. The majority of Streptococcus thermophilus phages can be divided into either cos - or pac -type phages and are additionally characterized by examining the V2 region of their antireceptors. We screened a large number of S. thermophilus phages from the Chr. Hansen A/S collection, using PCR specific for the cos - or pac -type phages, as well as for the V2 antireceptor region. Three phages did not produce positive results with the assays. Analysis of phage morphologies indicated that two of these phages, CHPC577 and CHPC926, had shorter tails than the traditional S. thermophilus phages. The third phage, CHPC1151, had a tail size similar to those of the cos - or pac -type phages, but it displayed a different baseplate structure. Sequencing analysis revealed the genetic similarity of CHPC577 and CHPC926 with a subgroup of Lactococcus lactis P335 phages. Phage CHPC1151 was closely related to the atypical S. thermophilus phage 5093, homologous with a nondairy streptococcal prophage. By testing adsorption of the related streptococcal and lactococcal phages to the surface of S. thermophilus and L. lactis strains, we revealed the possibility of cross-interactions. Our data indicated that the use of S. thermophilus together with L. lactis , extensively applied for dairy fermentations, triggered the recombination between phages infecting different bacterial species. A notable diversity among S. thermophilus phage populations requires that a new classification of the group be proposed. IMPORTANCE Streptococcus thermophilus is a component of thermophilic starter cultures commonly used for cheese and yogurt production. Characterizing streptococcal phages, understanding their genetic relationships, and studying their interactions with various hosts are the necessary steps for preventing and controlling phage attacks that occur during dairy fermentations. Copyright © 2017 Szymczak et al.

  18. Shiga toxin-converting phages and the emergence of new pathogenic Escherichia coli: a world in motion

    PubMed Central

    Tozzoli, Rosangela; Grande, Laura; Michelacci, Valeria; Ranieri, Paola; Maugliani, Antonella; Caprioli, Alfredo; Morabito, Stefano

    2014-01-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) are pathogenic E. coli causing diarrhea, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). STEC are characterized by a constellation of virulence factors additional to Stx and have long been regarded as capable to cause HC and HUS when possessing the ability of inducing the attaching and effacing (A/E) lesion to the enterocyte, although strains isolated from such severe infections sometimes lack this virulence feature. Interestingly, the capability to cause the A/E lesion is shared with another E. coli pathogroup, the Enteropathogenic E. coli (EPEC). In the very recent times, a different type of STEC broke the scene causing a shift in the paradigm for HUS-associated STEC. In 2011, a STEC O104:H4 caused a large outbreak with more than 800 HUS and 50 deaths. Such a strain presented the adhesion determinants of Enteroaggregative E. coli (EAggEC). We investigated the possibility that, besides STEC and EAggEC, other pathogenic E. coli could be susceptible to infection with stx-phages. A panel of stx2-phages obtained from STEC isolated from human disease was used to infect experimentally E. coli strains representing all the known pathogenic types, including both diarrheagenic E. coli (DEC) and extra-intestinal pathogenic E. coli (ExPEC). We observed that all the E. coli pathogroups used in the infection experiments were susceptible to the infection. Our results suggest that the stx2-phages used may not have specificity for E. coli adapted to the intestinal environment, at least in the conditions used. Additionally, we could only observe transient lysogens suggesting that the event of stable stx2-phage acquisition occurs rarely. PMID:24999453

  19. Cost of abortions in Zambia: A comparison of safe abortion and post abortion care.

    PubMed

    Parmar, Divya; Leone, Tiziana; Coast, Ernestina; Murray, Susan Fairley; Hukin, Eleanor; Vwalika, Bellington

    2017-02-01

    Unsafe abortion is a significant but preventable cause of maternal mortality. Although induced abortion has been legal in Zambia since 1972, many women still face logistical, financial, social, and legal obstacles to access safe abortion services, and undergo unsafe abortion instead. This study provides the first estimates of costs of post abortion care (PAC) after an unsafe abortion and the cost of safe abortion in Zambia. In the absence of routinely collected data on abortions, we used multiple data sources: key informant interviews, medical records and hospital logbooks. We estimated the costs of providing safe abortion and PAC services at the University Teaching Hospital, Lusaka and then projected these costs to generate indicative cost estimates for Zambia. Due to unavailability of data on the actual number of safe abortions and PAC cases in Zambia, we used estimates from previous studies and from other similar countries, and checked the robustness of our estimates with sensitivity analyses. We found that PAC following an unsafe abortion can cost 2.5 times more than safe abortion care. The Zambian health system could save as much as US$0.4 million annually if those women currently treated for an unsafe abortion instead had a safe abortion.

  20. Advance in phage display technology for bioanalysis.

    PubMed

    Tan, Yuyu; Tian, Tian; Liu, Wenli; Zhu, Zhi; J Yang, Chaoyong

    2016-06-01

    Phage display technology has emerged as a powerful tool for target gene expression and target-specific ligand selection. It is widely used to screen peptides, proteins and antibodies with the advantages of simplicity, high efficiency and low cost. A variety of targets, including ions, small molecules, inorganic materials, natural and biological polymers, nanostructures, cells, bacteria, and even tissues, have been demonstrated to generate specific binding ligands by phage display. Phages and target-specific ligands screened by phage display have been widely used as affinity reagents in therapeutics, diagnostics and biosensors. In this review, comparisons of different types of phage display systems are first presented. Particularly, microfluidic-based phage display, which enables screening with high throughput, high efficiency and integration, is highlighted. More importantly, we emphasize the advances in biosensors based on phages or phage-derived probes, including nonlytic phages, lytic phages, peptides or proteins screened by phage display, phage assemblies and phage-nanomaterial complexes. However, more efficient and higher throughput phage display methods are still needed to meet an explosion in demand for bioanalysis. Furthermore, screening of cyclic peptides and functional peptides will be the hotspot in bioanalysis. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Abortion patients' perceptions of abortion regulation.

    PubMed

    Cockrill, Kate; Weitz, Tracy A

    2010-01-01

    Most states regulate abortion differently than other health care services. Examples of these regulations include mandating waiting periods and the provision of state-authored information, and prohibiting private and public insurance coverage for abortion. The primary purpose of this paper is to explore abortion patients' perspectives on these regulations. We recruited 20 participants from three abortion providing facilities located in two states in the U.S. South and Midwest. Using a survey and semistructured interview, we collected information about women's knowledge of abortion regulation and policy preferences. During the interviews, women weighed the pros and cons of abortion regulations. We used grounded theory analytical techniques and matrix analysis to organize and interpret the data. We discovered five themes in these women's considerations of regulation: responsibility, empathy, safe and accessible health care, privacy, and equity. Women in the study generally supported policies that they felt protected women or informed decisions. However, most women also opposed laws mandating two-day abortion appointments for women who were traveling long distances. Women tended to favor financial coverage of abortion, arguing that it could help poor women afford abortion or reduce state expenditures. Overall the study participants' opinions on abortion policy reflect key values for advocates and policy makers to consider: responsibility, empathy, safe and accessible health care, privacy, and equity. Future work should examine abortion regulations in light of these shared values. Laws that promote misinformation or prohibit accommodations of unique circumstances are not consistent the positions articulated by the subjects in our study. Copyright 2010 Jacobs Institute of Women

  2. Characterization of Vibrio parahaemolyticus and its specific phage from shrimp pond in Palk Strait, South East coast of India.

    PubMed

    Stalin, Nattan; Srinivasan, Pappu

    2016-11-01

    Phage therapy is an alternative and eco-friendly biocontrol agent to prevent and control multidrug resistant bacteria in the aquatic system. The aim of this study is to isolate and characterize the Vibrio parahaemolyticus and its potential lytic phage from Penaeus monodon growing-out by rearing in shrimp ponds in Palk Strait, South East coast of India. The conventional phenotypic characteristics and molecular identification was confirmed using 16S rRNA sequence and to determine the antibiotic resistant profiles. The V. parahaemolyticus phage was effective against V. parahaemolyticus through one-step growth experiments, phage survival was determined by long-term storage at various temperatures and pH. Further, transmission electron microscope (TEM) revealed that the lytic phage belongs to the Myoviridae family. The isolated lytic phage (VVP1) was more specific against N1A V. parahaemolyticus and was able to infect N7A V. parahaemolyticus, N3B and N13B Vibrio alginolyticus strains. Evaluation of microcosm studies with P. monodon larvae infected with V. parahaemolyticus showed the survival of larvae in the presence of phage treatment at 2.3 × 10 10  PFU/mL -1 was enhanced when compared with the control. This study provides the application of phage as a useful strategy to prevent and eliminate or reduce shrimp pathogenic V. parahaemolyticus in the aquaculture system. Copyright © 2016 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

  3. Engineering M13 for phage display.

    PubMed

    Sidhu, S S

    2001-09-01

    Phage display is achieved by fusing polypeptide libraries to phage coat proteins. The resulting phage particles display the polypeptides on their surfaces and they also contain the encoding DNA. Library members with particular functions can be isolated with simple selections and polypeptide sequences can be decoded from the encapsulated DNA. The technology's success depends on the efficiency with which polypeptides can be displayed on the phage surface, and significant progress has been made in engineering M13 bacteriophage coat proteins as improved phage display platforms. Functional display has been achieved with all five M13 coat proteins, with both N- and C-terminal fusions. Also, coat protein mutants have been designed and selected to improve the efficiency of heterologous protein display, and in the extreme case, completely artificial coat proteins have been evolved specifically as display platforms. These studies demonstrate that the M13 phage coat is extremely malleable, and this property can be used to engineer the phage particle specifically for phage display. These improvements expand the utility of phage display as a powerful tool in modern biotechnology.

  4. Abortion-Related Mortality in the United States 1998–2010

    PubMed Central

    Zane, Suzanne; Creanga, Andreea A.; Berg, Cynthia J.; Pazol, Karen; Suchdev, Danielle B.; Jamieson, Denise J.; Callaghan, William M.

    2015-01-01

    OBJECTIVE To examine characteristics and causes of legal induced abortion–related deaths in the United States between 1998 and 2010. METHODS Abortion-related deaths were identified through the national Pregnancy Mortality Surveillance System with enhanced case-finding. We calculated the abortion mortality rate by race, maternal age, and gestational age and the distribution of causes of death by gestational age and procedure. RESULTS During the period from 1998–2010, of approximately 16.1 million abortion procedures, 108 women died, for a mortality rate of 0.7 deaths per 100,000 procedures overall, 0.4 deaths for non-Hispanic white women, 0.5 deaths for Hispanic women, and 1.1 deaths for black women. The mortality rate increased with gestational age, from 0.3 to 6.7 deaths for procedures performed at 8 weeks or less and at 18 weeks or greater, respectively. A majority of abortion-related deaths at 13 weeks of gestation or less were associated with anesthesia complications and infection, whereas a majority of abortion-related deaths at more than 13 weeks of gestation were associated with infection and hemorrhage. In 20 of the 108 cases, the abortion was performed as a result of a severe medical condition where continuation of the pregnancy threatened the woman’s life. CONCLUSION Deaths associated with legal induced abortion continue to be rare events—less than 1 per 100,000 procedures. Primary prevention of unintended pregnancy, including those in women with serious pre-existing medical conditions, and increased access to abortion services at early gestational ages may help to further decrease abortion-related mortality in the United States. PMID:26241413

  5. Complete genome sequence of a phage hyperparasite of Candidatus Xenohaliotis californiensis (Rickettsiales) - a pathogen of Haliotis spp (Gasteropoda).

    PubMed

    Cruz-Flores, Roberto; Cáceres-Martínez, Jorge; Del Río-Portilla, Miguel Ángel; Licea-Navarro, Alexei F; Gonzales-Sánchez, Ricardo; Guerrero, Abraham

    2018-04-01

    Bacteriophages are recognized as major mortality agents of microbes, among them intracellular marine rickettsiales-like bacteria. Recently, a phage hyperparasite of Candidatus Xenohaliotis californiensis (CXc) has been described. This bacterium is considered the causal agent of Withering Syndrome (WS) which is a chronic and potentially lethal disease of abalone species from California, USA and the peninsula of Baja California, Mexico. This hyperparasite which infects CXc could be used as a biocontrol agent for WS. Therefore, it is necessary to obtain genomic information to characterize this phage. In this study, the first complete genome sequence of a novel phage, Xenohaliotis phage (pCXc) was determined. The complete genome of pCXc from red abalone (Haliotis rufescens) is 35,728 bp, while the complete genome of pCXc from yellow abalone (Haliotis corrugata) is 35,736 bp. Both phage genomes consist of double-stranded DNA with a G + C content of 38.9%. In both genomes 33 open reading frames (ORFs) were predicted. Only 10 ORFs encode proteins that have identifiable functional homologues. These 10 ORFs were classified by function, including structural, DNA replication, DNA packaging, nucleotide transport and metabolism, life cycle regulation, recombination and repair, and additional functions. A PCR method for the specific detection of pCXc was developed. This information will help to understand a new group of phages that infect intracellular marine rickettsiales-like bacteria in mollusks.

  6. Immune TB Antibody Phage Display Library as a Tool To Study B Cell Immunity in TB Infections.

    PubMed

    Hamidon, Nurul Hamizah; Suraiya, Siti; Sarmiento, Maria E; Acosta, Armando; Norazmi, Mohd Nor; Lim, Theam Soon

    2018-03-01

    B cells and in particular antibodies has always played second fiddle to cellular immunity in regard to tuberculosis (TB). However, recent studies has helped position humoral immunity especially antibodies back into the foray in relation to TB immunity. Therefore, the ability to correlate the natural antibody responses of infected individuals toward TB antigens would help strengthen this concept. Phage display is an intriguing approach that can be utilized to study antibody-mediated responses against a particular infection via harvesting the B cell repertoire from infected individuals. The development of disease-specific antibody libraries or immune libraries is useful to better understand antibody-mediated immune responses against specific disease antigens. This study describes the generation of an immune single-chain variable fragment (scFv) library derived from TB-infected individuals. The immune library with an estimated diversity of 10 9 independent clones was then applied for the identification of monoclonal antibodies against Mycobacterium tuberculosis α-crystalline as a model antigen. Biopanning of the library isolated three monoclonal antibodies with unique gene usage. This strengthens the role of antibodies in TB immunity in addition to the role played by cellular immunity. The developed library can be applied against other TB antigens and aid antibody-derived TB immunity studies in the future.

  7. Recombinant phage probes for Listeria monocytogenes

    NASA Astrophysics Data System (ADS)

    Carnazza, S.; Gioffrè, G.; Felici, F.; Guglielmino, S.

    2007-10-01

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 104 cells ml-1. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

  8. Medical abortion and manual vacuum aspiration for legal abortion protect women's health and reduce costs to the health system: findings from Colombia.

    PubMed

    Rodriguez, Maria Isabel; Mendoza, Willis Simancas; Guerra-Palacio, Camilo; Guzman, Nelson Alvis; Tolosa, Jorge E

    2015-02-01

    The majority of abortions in Colombia continue to take place outside the formal health system under a range of conditions, with the majority of women obtaining misoprostol from a thriving black market for the drug and self-administering the medication. We conducted a cost analysis to compare the costs to the health system of three approaches to the provision of abortion care in Colombia: post-abortion care for complications of unsafe abortions, and for legal abortions in a health facility, misoprostol-only medical abortion and vacuum aspiration abortion. Hospital billing records from three institutions, two large maternity hospitals and one specialist reproductive health clinic, were analysed for procedure and complication rates, and costs by diagnosis. The majority of visits (94%) were to the two hospitals for post-abortion care; the other 6% were for legal abortions. Only one minor complication was found among the women having legal abortions, a complication rate of less than 1%. Among the women presenting for post-abortion care, 5% had complications during their treatment, mainly from infection or haemorrhage. Legal abortions were associated not only with far fewer complications for women, but also lower costs for the health system than for post-abortion care. We calculated based on our findings that for every 1,000 women receiving post-abortion care instead of a legal abortion within the health system, 16 women experienced avoidable complications, and the health system spent US $48,000 managing them. Increasing women's access to safe abortion care would not only reduce complications for women, but would also be a cost-saving strategy for the health system. Copyright © 2015 Reproductive Health Matters. Published by Elsevier Ltd. All rights reserved.

  9. Phage-displayed peptides selected for binding to Campylobacter jejuni are antimicrobial.

    PubMed

    Bishop-Hurley, Sharon L; Rea, Philippa J; McSweeney, Christopher S

    2010-10-01

    In developed countries, Campylobacter jejuni is a leading cause of zoonotic bacterial gastroenteritis in humans with chicken meat implicated as a source of infection. Campylobacter jejuni colonises the lower gastrointestinal tract of poultry and during processing is spread from the gastrointestinal tract onto the surface of dressed carcasses. Controlling or eliminating C.jejuni on-farm is considered to be one of the best strategies for reducing human infection. Molecules on the cell surface of C.jejuni interact with the host to facilitate its colonisation and persistence in the gastrointestinal tract of poultry. We used a subtractive phage-display protocol to affinity select for peptides binding to the cell surface of a poultry isolate of C.jejuni with the aim of finding peptides that could be used to control this microorganism in chickens. In total, 27 phage peptides, representing 11 unique clones, were found to inhibit the growth of C.jejuni by up to 99.9% in vitro. One clone was bactericidal, reducing the viability of C.jejuni by 87% in vitro. The phage peptides were highly specific. They completely inhibited the growth of two of the four poultry isolates of C.jejuni tested with no activity detected towards other Gram-negative and Gram-positive bacteria.

  10. Spatial Vulnerability: Bacterial Arrangements, Microcolonies, and Biofilms as Responses to Low Rather than High Phage Densities

    PubMed Central

    Abedon, Stephen T.

    2012-01-01

    The ability of bacteria to survive and propagate can be dramatically reduced upon exposure to lytic bacteriophages. Study of this impact, from a bacterium’s perspective, tends to focus on phage-bacterial interactions that are governed by mass action, such as can be observed within continuous flow or similarly planktonic ecosystems. Alternatively, bacterial molecular properties can be examined, such as specific phage‑resistance adaptations. In this study I address instead how limitations on bacterial movement, resulting in the formation of cellular arrangements, microcolonies, or biofilms, could increase the vulnerability of bacteria to phages. Principally: (1) Physically associated clonal groupings of bacteria can represent larger targets for phage adsorption than individual bacteria; and (2), due to a combination of proximity and similar phage susceptibility, individual bacteria should be especially vulnerable to phages infecting within the same clonal, bacterial grouping. Consistent with particle transport theory—the physics of movement within fluids—these considerations are suggestive that formation into arrangements, microcolonies, or biofilms could be either less profitable to bacteria when phage predation pressure is high or require more effective phage-resistance mechanisms than seen among bacteria not living within clonal clusters. I consider these ideas of bacterial ‘spatial vulnerability’ in part within a phage therapy context. PMID:22754643

  11. Phage display for generating peptide reagents.

    PubMed

    Brigati, Jennifer R; Samoylova, Tatiana I; Jayanna, Prashanth K; Petrenko, Valery A

    2008-02-01

    This unit presents detailed protocols for selection and propagation of landscape phages, which are fusions of filamentous phage fd (or its close relatives M13 and f1) and foreign DNA that result in chimeric phage virions with foreign peptides (8 to 9 amino acids long) covering the entire surface of the phage particles. These landscape phages bind specifically to mammalian and bacterial cells, spores, or discrete molecular targets. (c) 2008 by John Wiley & Sons, Inc.

  12. Current insights into phage biodiversity and biogeography.

    PubMed

    Thurber, Rebecca Vega

    2009-10-01

    Phages exert tremendous ecological and evolutionary forces directly on their bacterial hosts. Phage induced cell lysis also indirectly contributes to organic and inorganic nutrient recycling. Phage abundance, diversity, and distribution are therefore important parameters in ecosystem function. The assumption that phage consortia are ubiquitous and homogenous across habitats (everything is everywhere) is currently being re-evaluated. New studies on phage biogeography have found that some phages are globally distributed while others are unique and perhaps endemic to specific environments. Furthermore, advances in technology have allowed scientists to conduct experiments aimed at analyzing phage consortia over temporal scales, and surprisingly have found reoccurring patterns. This review discusses currents in the field of phage ecology with particular focus on efforts to characterize phage diversity and biogeography across various spatial and temporal scales.

  13. Abortion.

    PubMed

    1993-05-01

    The Alan Guttmacher Institute's State Reproductive Health Monitor "Legislative Proposals and Actions" provides US legislative information on abortion. The listing contains information on pending bills: the state, the identifying legislative number, the sponsor, the committee, the date the bill was introduced, a description of the bill, and when available the bill's status. The bills cover: 1) clinic licensing, e.g., requiring outpatient health care facilities in which abortions are performed, to have malpractice liability insurance; 2) comprehensive statues, which require parental notification before minor may obtain abortions, mandate abortion counseling to all women 24 hours before the abortion can be performed and prohibit disciplining or discharging a state employee for refusing to provide abortion counseling; 3) fetal personhood and rights, e.g. providing that life is vested in each person at fertilization; 4) fetal research and remains; 5) gender of fetus, which regulate abortions relative to sex selection in pregnancies; 6) harassment regulation; 7) informed consent and waiting periods detailing the risks and alternatives to abortion, and the 24-hour waiting period; 8) insurance coverage, e.g., eliminating language banning the coverage of abortions for state workers, and prohibiting disclosure by a health insurance carrier to the employer of a claimant that the claimant had a surgical abortion; 9) legality of abortion, urging Congress to reject he Freedom of Choice Act; 10) parental consent and notification; 11) postviability requirements; 12) public funding; 13) reporting requirements; 14) reproductive rights, and 15) spousal and paternal consent and notification.

  14. PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

    PubMed Central

    Price, Winston H.

    1950-01-01

    1. Four strains of Staphylococcus muscae have been isolated which differ in their growth rates and phage syntheses in Fildes' synthetic medium. 2. Two of the strains when singly infected cannot release phage in Fildes' synthetic medium unless a substance present in certain acid-hydrolyzed proteins is added to the medium. One of these strains also requires other substance(s) present in acid-hydrolyzed proteins in order to grow in Fildes' medium. 3. The two strains which do not require the addition of the phage-stimulating factor have been found either to synthesize this substance, or one similar to it. One of these strains will not grow in Fildes' medium unless substance(s) present in acid-hydrolyzed proteins is added to the medium. 4. The purified acid-hydrolyzed protein factor necessary for virus liberation does not affect the multiplication rate of uninfected S. muscae cells in Fildes' synthetic medium. 5. The substance is not needed for the adsorption or the invasion of the host cell by the virus. In the absence of the factor, the virus is adsorbed to the cell and "kills" it. 6. An analysis carried out by means of the one-step growth curve technique has indicated that the substance is not concerned simply with the mechanism of virus release, but is necessary for some initial stage in virus synthesis. 7. With one bacterial strain not requiring the AHPF, aspartic acid had to be present at least during the minimum latent period for the cell to form virus. 8. In the absence of aspartic acid, the virus was adsorbed to the cell and killed it, but no virus was released from singly infected bacteria. 9. If the cells were grown in a medium containing aspartic acid and then resuspended in the medium minus aspartic acid, no virus was released, although such cells contained at least two times the amount of aspartic acid necessary for the burst size in the complete medium. 10. Aspartic acid, a constituent of the virus particle, appears from an analysis of one-step growth

  15. [Abortion and rights. Legal thinking about abortion].

    PubMed

    Perez Duarte, A E

    1991-01-01

    Analysis of abortion in Mexico from a juridical perspective requires recognition that Mexico as a national community participates in a double system of values. Politically it is defined as a liberal, democratic, and secular state, but culturally the Judeo-Christian ideology is dominant in all social strata. This duality complicates all juridical-penal decisions regarding abortion. Public opinion on abortion is influenced on the 1 hand by extremely conservative groups who condemn abortion as homicide, and on the other hand by groups who demand legislative reform in congruence with characteristics that define the state: an attitude of tolerance toward the different ideological-moral positions that coexist in the country. The discussion concerns the rights of women to voluntary maternity, protection of health, and to making their own decisions regarding their bodies vs. the rights of the fetus to life. The type of analysis is not objective, and conclusions depend on the ideology of the analyst. Other elements must be examined for an objective consideration of the social problem of abortion. For example, aspects related to maternal morbidity and mortality and the demographic, economic, and physical and mental health of the population would all seem to support the democratic juridical doctrine that sees the clandestine nature of abortion as the principal problem. It is also observed that the illegality of abortion does not guarantee its elimination. Desperate women will seek abortion under any circumstances. The illegality of abortion also impedes health and educational policies that would lower abortion mortality. There are various problems from a strictly juridical perspective. A correct definition of the term abortion is needed that would coincide with the medical definition. The discussion must be clearly centered on the protected juridical right and the definition of reproductive and health rights and rights to their own bodies of women. The experiences of other

  16. Corruption of phage-display libraries by target-unrelated clones: Diagnosis and countermeasures

    PubMed Central

    Thomas, William D.; Golomb, Miriam; Smith, George P.

    2010-01-01

    Phage display is used to discover peptides or proteins with a desired target property—most often, affinity for a target selector molecule. Libraries of phage clones displaying diverse surface peptides are subject to a selection process designed to enrich for the target behavior, and subsequently propagated to restore phage numbers. A recurrent problem is enrichment of clones, called target-unrelated phage (TUPs), that lack the target behavior. Many TUPs are propagation-related; they have mutations conferring a growth advantage, and are enriched during the propagations accompanying selection. Unlike other filamentous phage libraries, fd-tet-based libraries are relatively resistant to propagation-related TUP corruption. Their minus strand origin is disrupted by a large cassette that simultaneously confers resistance to tetracycline and imposes a rate-limiting growth defect that cannot be bypassed with simple mutations. Nonetheless, a new type of propagation-related TUP emerged in the output of in vivo selections from an fd-tet library. The founding clone had a complex rearrangement that restored the minus strand origin while retaining tetracycline resistance. The rearrangement involved two recombination events, one with a contaminant having a wild-type minus strand origin. The founder’s infectivity advantage spread by simple recombination to clones displaying different peptides. We propose measures for minimizing TUP corruption. PMID:20692225

  17. Induced abortion among Brazilian female sex workers: a qualitative study.

    PubMed

    Madeiro, Alberto Pereira; Diniz, Debora

    2015-02-01

    Prostitutes are vulnerable to unplanned pregnancies and abortions. In Brazil, abortion is a crime and there is no data about unsafe abortions for this population. The study describes how prostitutes perform illegal abortions and the health consequences thereof. Semi-structured interviews with 39 prostitutes from three cities in Brazil with previous induced abortion experience were conducted. Sixty-six abortions, with between one and eight occurrences per woman, were recorded. The majority of the cases resulted from sexual activity with clients. The inconsistent use of condoms with regular clients and the consumption of alcohol during work were indicated as the main causes of unplanned pregnancies. The main method to perform abortion was the intravaginal and oral use of misoprostol, acquired in pharmacies or on the black market. Invasive measures were less frequently reported, however with more serious health complications. The fear of complaint to the police meant that most women do not inform the health team regarding induced abortion. The majority of prostitutes aborted with the use of illegally-acquired misoprostol, ending abortion in a public hospital with infection and hemorrhagic complications. The data indicate the need for a public policy focusing on the reproductive health of prostitutes.

  18. Humoral immune responses against gonadotropin releasing hormone elicited by immunization with phage-peptide constructs obtained via phage display.

    PubMed

    Samoylov, Alexandre; Cochran, Anna; Schemera, Bettina; Kutzler, Michelle; Donovan, Caitlin; Petrenko, Valery; Bartol, Frank; Samoylova, Tatiana

    2015-12-20

    Phage display is based on genetic engineering of phage coat proteins resulting in fusion peptides displayed on the surface of phage particles. The technology is widely used for generation of phages with novel characteristics for numerous applications in biomedicine and far beyond. The focus of this study was on development of phage-peptide constructs that stimulate production of antibodies against gonadotropin releasing hormone (GnRH). Phage-peptide constructs that elicit production of neutralizing GnRH antibodies can be used for anti-fertility and anti-cancer applications. Phage-GnRH constructs were generated via selection from a phage display library using several types of GnRH antibodies as selection targets. Such phage constructs were characterized for sequence similarities to GnRH peptide and frequency of their occurrence in the selection rounds. Five of the constructs with suitable characteristics were tested in mice as a single dose 5×10(11) virions (vir) vaccine and were found to be able to stimulate production of GnRH-specific antibodies, but not to suppress testosterone (indirect indicator of GnRH antibody neutralizing properties). Next, one of the constructs was tested at a higher dose of 2×10(12) vir per mouse in combination with a poly(lactide-co-glycolide) (PLGA)-based adjuvant. This resulted in multifold increase in GnRH antibody production and significant reduction of serum testosterone, indicating that antibodies produced in response to the phage-GnRH immunization possess neutralizing properties. To achieve optimal immune responses for desired applications, phage-GnRH constructs can be modified with respect to flanking sequences of GnRH-like peptides displayed on phage. Anticipated therapeutic effects also might be attained using optimized phage doses, a combination of several constructs in a single treatment, or application of adjuvants and advanced phage delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Antibiotics for treating septic abortion.

    PubMed

    Udoh, Atim; Effa, Emmanuel E; Oduwole, Olabisi; Okusanya, Babasola O; Okafo, Obiamaka

    2016-07-01

    A septic abortion refers to any abortion (spontaneous or induced) complicated by upper genital tract infection including endometritis or parametritis. The mainstay of treatment of septic abortion is antibiotic therapy alone or in combination with evacuation of retained products of conception. Regimens including broad-spectrum antibiotics are routinely recommended for treatment. However, there is no consensus on the most effective antibiotics alone or in combination to treat septic abortion. This review aimed to bridge this gap in knowledge to inform policy and practice. To review the effectiveness of various individual antibiotics or antibiotic regimens in the treatment of septic abortion. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, and POPLINE using the following keywords: 'Abortion', 'septic abortion', 'Antibiotics', 'Infected abortion', 'postabortion infection'. We also searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov for ongoing trials on 19 April, 2016. We considered for inclusion randomised controlled trials (RCTs) and non-RCTs that compared antibiotic(s) to another antibiotic(s), irrespective of route of administration, dosage, and duration as well as studies comparing antibiotics alone with antibiotics in combination with other interventions such as dilation and curettage (D&C). Two review authors independently extracted data from included trials. We resolved disagreements through consultation with a third author. One review author entered extracted data into Review Manager 5.3, and a second review author cross-checked the entry for accuracy. We included 3 small RCTs involving 233 women that were conducted over 3 decades ago.Clindamycin did not differ significantly from penicillin plus chloramphenicol in reducing fever in all women (mean difference (MD) -12.30, 95% confidence interval (CI) -25.12 to 0.52; women = 77; studies = 1

  20. International developments in abortion laws: 1977-88.

    PubMed

    Cook, R J; Dickens, B M

    1989-08-01

    International developments in abortion laws have been diverse, but the general thrust of legislation and court decisions has been towards decriminalization and liberalization of laws and the reduction of legal barriers to access to therapuetic abortion services presented by spousal and parental authorization requirements. Most legislation has extended abortion eligibility through traditional indications such as danger to maternal health or fetal handicap, but other indications have also been created, such as adolescence, advanced maternal age, family circumstances and Acquired Immunodeficiency Syndrome or Human Immunodeficiency Virus infection. Several jurisdictions established stages of early gestation within which abortion could be undertaken with minimal legal scrutiny. In Canada, the entire prohibition of abortion was held unconstitutional for violating women's integrity and security. Under medical and public health guidance, several countries have amended their constitutions to recognize and protect human life from contraception. Cyprus, Italy, and Taiwan have created an indication for abortion of welfare of the women's family, while France and the Netherlands recognize the women's distress and Hungary cites cases where the women is single or separated for 6 months, where appropriate housing is lacking or where she is 35 years or older and has had 3 deliveries. National health services and insurance schemes vary in their coverage of abortion costs, but generally tend to fund the major park of lawful services. In Britain, France, Israel, the US and Yugoslavia husband's claims to veto abortions have been rejected. Courts have also established that mature adolescents, although legally minors, may give autonomous consent to abortion and are entitled to confidentiality. Few countries' laws define when criminal abortion liability commences or when conception occurs, but the law has moved to restrict abortion in Israel, Honduras, Romania and Finland.

  1. Metagenomic Analysis of Therapeutic PYO Phage Cocktails from 1997 to 2014

    PubMed Central

    Larsen, Mette Voldby

    2017-01-01

    Phage therapy has regained interest in recent years due to the alarming spread of antibiotic resistance. Whilst phage cocktails are commonly sold in pharmacies in countries such as Georgia and Russia, this is not the case in western countries due to western regulatory agencies requiring a thorough characterization of the drug. Here, DNA sequencing of constituent biological entities constitutes a first step. The pyophage (PYO) cocktail is one of the main commercial products of the Georgian Eliava Institute of Bacteriophage, Microbiology and Virology and is used to cure skin infections. Since its first production in the 1930s, the composition of the cocktail has been periodically modified to add phages effective against emerging pathogenic strains. In this paper, we compared the composition of three PYO cocktails from 1997 (PYO97), 2000 (PYO2000) and 2014 (PYO2014). Based on next generation sequencing, de novo assembly and binning of contigs into draft genomes based on tetranucleotide distance, thirty and twenty-nine phage draft genomes were predicted in PYO97 and PYO2014, respectively. Of these, thirteen and fifteen shared high similarity to known phages. Eleven draft genomes were found to be common in the two cocktails. One of these showed no similarity to publicly available phage genomes. Representatives of phages targeting E. faecalis, E. faecium, E. coli, Proteus, P. aeruginosa and S. aureus were found in both cocktails. Finally, we estimated larger overlap of the PYO2000 cocktail to PYO97 compared to PYO2014. Using next generation sequencing and metagenomics analysis, we were able to characterize and compare the content of PYO cocktails separated by 17 years in time. Even though the cocktail composition is upgraded every six months, we found it to remain relatively stable over the years. PMID:29099783

  2. Abundant and diverse clustered regularly interspaced short palindromic repeat spacers in Clostridium difficile strains and prophages target multiple phage types within this pathogen.

    PubMed

    Hargreaves, Katherine R; Flores, Cesar O; Lawley, Trevor D; Clokie, Martha R J

    2014-08-26

    Clostridium difficile is an important human-pathogenic bacterium causing antibiotic-associated nosocomial infections worldwide. Mobile genetic elements and bacteriophages have helped shape C. difficile genome evolution. In many bacteria, phage infection may be controlled by a form of bacterial immunity called the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system. This uses acquired short nucleotide sequences (spacers) to target homologous sequences (protospacers) in phage genomes. C. difficile carries multiple CRISPR arrays, and in this paper we examine the relationships between the host- and phage-carried elements of the system. We detected multiple matches between spacers and regions in 31 C. difficile phage and prophage genomes. A subset of the spacers was located in prophage-carried CRISPR arrays. The CRISPR spacer profiles generated suggest that related phages would have similar host ranges. Furthermore, we show that C. difficile strains of the same ribotype could either have similar or divergent CRISPR contents. Both synonymous and nonsynonymous mutations in the protospacer sequences were identified, as well as differences in the protospacer adjacent motif (PAM), which could explain how phages escape this system. This paper illustrates how the distribution and diversity of CRISPR spacers in C. difficile, and its prophages, could modulate phage predation for this pathogen and impact upon its evolution and pathogenicity. Clostridium difficile is a significant bacterial human pathogen which undergoes continual genome evolution, resulting in the emergence of new virulent strains. Phages are major facilitators of genome evolution in other bacterial species, and we use sequence analysis-based approaches in order to examine whether the CRISPR/Cas system could control these interactions across divergent C. difficile strains. The presence of spacer sequences in prophages that are homologous to phage genomes raises an

  3. Are Phage Lytic Proteins the Secret Weapon To Kill Staphylococcus aureus?

    PubMed

    Gutiérrez, Diana; Fernández, Lucía; Rodríguez, Ana; García, Pilar

    2018-01-23

    Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most threatening microorganisms for global human health. The current strategies to reduce the impact of S. aureus include a restrictive control of worldwide antibiotic use, prophylactic measures to hinder contamination, and the search for novel antimicrobials to treat human and animal infections caused by this bacterium. The last strategy is currently the focus of considerable research. In this regard, phage lytic proteins (endolysins and virion-associated peptidoglycan hydrolases [VAPGHs]) have been proposed as suitable candidates. Indeed, these proteins display narrow-spectrum antimicrobial activity and a virtual lack of bacterial-resistance development. Additionally, the therapeutic use of phage lytic proteins in S. aureus animal infection models is yielding promising results, showing good efficacy without apparent side effects. Nonetheless, human clinical trials are still in progress, and data are not available yet. This minireview also analyzes the main obstacles for introducing phage lytic proteins as human therapeutics against S. aureus infections. Besides the common technological problems derived from large-scale production of therapeutic proteins, a major setback is the lack of a proper legal framework regulating their use. In that sense, the relevant health authorities should urgently have a timely discussion about these new antimicrobials. On the other hand, the research community should provide data to dispel any doubts regarding their efficacy and safety. Overall, the appropriate scientific data and regulatory framework will encourage pharmaceutical companies to invest in these promising antimicrobials. Copyright © 2018 Gutiérrez et al.

  4. Phage particles harboring antibiotic resistance genes in fresh-cut vegetables and agricultural soil.

    PubMed

    Larrañaga, Olatz; Brown-Jaque, Maryury; Quirós, Pablo; Gómez-Gómez, Clara; Blanch, Anicet R; Rodríguez-Rubio, Lorena; Muniesa, Maite

    2018-06-01

    Bacteriophages are ubiquitously distributed prokaryotic viruses that are more abundant than bacteria. As a consequence of their life cycle, phages can kidnap part of their host's genetic material, including antibiotic resistance genes (ARGs), which released phage particles transfer in a process called transduction. The spread of ARGs among pathogenic bacteria currently constitutes a serious global health problem. In this study, fresh vegetables (lettuce, spinach and cucumber), and cropland soil were screened by qPCR for ten ARGs (bla TEM , bla CTX-M-1 group, bla CTX-M-9 group, bla OXA-48 , bla VIM , mecA, sul1, qnrA, qnrS and armA) in their viral DNA fraction. The presence of ARGs in the phage DNA was analyzed before and after propagation experiments in an Escherichia coli host strain to evaluate the ability of the phage particles to infect a host. ARGs were found in the phage DNA fraction of all matrices, although with heterogeneous values. ARG prevalence was significantly higher in lettuce and soil, and the most common overall were β-lactamases. After propagation experiments, an increase in ARG densities in phage particles was observed in samples of all four matrices, confirming that part of the isolated phage particles were infectious. This study reveals the abundance of free, replicative ARG-containing phage particles in vegetable matrices and cropland soil. The particles are proposed as vehicles for resistance transfer in these environments, where they can persist for a long time, with the possibility of generating new resistant bacterial strains. Ingestion of these mobile genetic elements may also favor the emergence of new resistances, a risk not previously considered. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Phage-host interactions analysis of newly characterized Oenococcus oeni bacteriophages: Implications for malolactic fermentation in wine.

    PubMed

    Costantini, Antonella; Doria, Francesca; Saiz, Juan-Carlos; Garcia-Moruno, Emilia

    2017-04-04

    Nowadays, only few phages infecting Oenococcus oeni, the principal lactic acid bacteria (LAB) species responsible for malolactic fermentation (MLF) in wine, have been characterized. In the present study, to better understanding the factors affecting the lytic activity of Oenococcus phages, fifteen O. oeni bacteriophages have been studied in detail, both with molecular and microbiological methods. No correlations were found between genome sizes, type of integrase genes, or morphology and the lytic activity of the 15 tested phages. Interestingly, though phage attack in a wine at the end of alcoholic fermentation seems not to be a problem, it can indeed represent a risk factor for MLF when the alcohol content is low, feature that may be a key point for choosing the appropriate time for malolactic starter inoculation. Additionally, it was observed that some phages genomes bear 2 or 3 types of integrase genes, which point to horizontal gene transfer between O. oeni bacteriophages. Copyright © 2017. Published by Elsevier B.V.

  6. Decoupling of Host–Symbiont–Phage Coadaptations Following Transfer Between Insect Species

    PubMed Central

    Chafee, Meghan E.; Zecher, Courtney N.; Gourley, Michelle L.; Schmidt, Victor T.; Chen, John H.; Bordenstein, Sarah R.; Clark, Michael E.; Bordenstein, Seth R.

    2011-01-01

    Transferring endosymbiotic bacteria between different host species can perturb the coordinated regulation of the host and bacterial genomes. Here we use the most common maternally transmitted bacteria, Wolbachia pipientis, to test the consequences of host genetic background on infection densities and the processes underlying those changes in the parasitoid wasp genus Nasonia. Introgressing the genome of Nasonia giraulti into the infected cytoplasm of N. vitripennis causes a two-order-of-magnitude increase in bacterial loads in adults and a proliferation of the infection to somatic tissues. The host effect on W. pipientis distribution and densities is associated with a twofold decrease in densities of the temperate phage WO-B. Returning the bacteria from the new host species back to the resident host species restores the bacteria and phage to their native densities. To our knowledge, this is the first study to report a host–microbe genetic interaction that affects the densities of both W. pipientis and bacteriophage WO-B. The consequences of the increased bacterial density include a reduction in fecundity, an increase in levels of cytoplasmic incompatibility (CI), and unexpectedly, male-to-female transfer of the bacteria to uninfected females and an increased acceptance of densely infected females to interspecific mates. While paternal inheritance of the W. pipientis was not observed, the high incidence of male-to-female transfer in the introgressed background raises the possibility that paternal transmission could be more likely in hybrids where paternal leakage of other cytoplasmic elements is also known to occur. Taken together, these results establish a major change in W. pipientis densities and tissue tropism between closely related species and support a model in which phage WO, Wolbachia, and arthropods form a tripartite symbiotic association in which all three are integral to understanding the biology of this widespread endosymbiosis. PMID:20944019

  7. Therapeutic Antibodies by Phage Display.

    PubMed

    Shim, Hyunbo

    2016-01-01

    Antibody phage display is a major technological platform for the generation of fully human antibodies for therapeutic purposes. The in vitro binder selection by phage display allows researchers to have more extensive control over binding parameters and facilitates the isolation of clinical candidate antibodies with desired binding and/or functional profiles. Since the invention of antibody phage display in late 1980s, significant technological advancements in the design, construction, and selection of the antibody libraries have been made, and several fully human antibodies generated by phage display are currently approved or in various clinical development stages. In this review, the background and details of antibody phage display technology, and representative antibody libraries with natural or synthetic sequence diversity and different construction strategies are described. The generation, optimization, functional and biophysical properties, and preclinical and clinical developments of some of the phage display-derived therapeutic antibodies approved for use in patients or in late-stage clinical trials are also discussed. With evolving novel disease targets and therapeutic strategies, antibody phage display is expected to continue to play a central role in the development of the next generation of therapeutic antibodies. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. Investigating the biocontrol and anti-biofilm potential of a three phage cocktail against Cronobacter sakazakii in different brands of infant formula.

    PubMed

    Endersen, Lorraine; Buttimer, Colin; Nevin, Eoghan; Coffey, Aidan; Neve, Horst; Oliveira, Hugo; Lavigne, Rob; O'Mahony, Jim

    2017-07-17

    In recent years, the microbiological safety of powdered infant formula has gained increasing attention due to the identification of contaminating C. sakazakii and its epidemiological link with life-threatening neonatal infections. Current intervention strategies have fallen short of ensuring the production of infant formula that is free from C. sakazakii. In this study, we describe the isolation and characterisation of three bacteriophages (phages) and their application as a phage cocktail to inhibit the growth of C. sakazakii in different brands of infant formula, while also assessing the phages ability to prevent biofilm formation. All three phages, isolated from slurry, possess a relatively broad host range, verified by their ability to infect across genera and species. When all three phages were combined and used as part of a phage cocktail, 73% coverage was obtained across all Cronobacter strains tested. Optimum thermo-tolerance and pH stability were determined between 4°C-37°C, and pH6-8, respectively, well within the normal range of application of infant formula. Genome sequencing and analysis revealed all the phages to be free from lysogenic properties, a trait which renders each favourable for phage therapy applications. As such, the combined-phage preparation (3×10 8 pfu/mL) was found to possess a strong bactericidal effect on C. sakazakii/C. sakazakii LUX cells (≤10 4 cfu/mL), resulting in a significant reduction in cell numbers, to below the limit of detection (<10cfu/mL). This was observed following a 20h challenge in different brands of infant formula, where samples in the absence of the phage cocktail reached concentrations of ~10 9 cfu/mL. The phage cocktail also demonstrated promise in preventing the establishment of biofilm, as biofilm formation could not be detected for up to 48h post treatment. These results highlight the potential application of this phage preparation for biocontrol of C. sakazakii contamination in reconstituted infant

  9. Chlamydia pecorum: fetal and placental lesions in sporadic caprine abortion.

    PubMed

    Giannitti, Federico; Anderson, Mark; Miller, Myrna; Rowe, Joan; Sverlow, Karen; Vasquez, Marce; Cantón, Germán

    2016-03-01

    Chlamydial abortion in small ruminants is usually associated with Chlamydia abortus infection. Although Chlamydia pecorum has been detected in aborted ruminants and epidemiological data suggests that C. pecorum is abortigenic in these species, published descriptions of lesions in fetuses are lacking. This work describes fetoplacental lesions in a caprine abortion with C. pecorum infection, and further supports the abortigenic role of C. pecorum in ruminants. A 16-month-old Boer goat aborted twin fetuses at ~130 days of gestation. Both fetuses (A and B) and the placenta of fetus A were submitted for postmortem examination and diagnostic workup. At autopsy, the fetuses had moderate anasarca, intermuscular edema in the hindquarters (A), and brachygnathia and palatoschisis (B). In the placenta, the cotyledons were covered by yellow fibrinosuppurative exudate that extended into the adjacent intercotyledonary areas. Histologically, there was severe suppurative and necrotizing placentitis with vasculitis (arteriolitis) and thrombosis, multifocal lymphohistiocytic and neutrophilic hepatitis (A), and fibrinosuppurative enteritis in both fetuses. Chlamydia antigen was detected in the placenta by the direct fluorescent antibody test and in fetal intestines by immunohistochemistry. Nested polymerase chain reaction of DNA extracted from formalin-fixed, paraffin-embedded sections of placenta and intestine amplified 400 bp of the Chlamydia 16S rRNA gene that was sequenced and found to be 99% identical to C. pecorum by BLAST analysis. Other known abortigenic infectious agents were ruled out by specific testing. It is concluded that C. pecorum infection is associated with fetoplacental lesions and sporadic abortion in goats. © 2015 The Author(s).

  10. Efficacy and Safety of a Bovine-Associated Staphylococcus aureus Phage Cocktail in a Murine Model of Mastitis.

    PubMed

    Breyne, Koen; Honaker, Ryan W; Hobbs, Zachary; Richter, Manuela; Żaczek, Maciej; Spangler, Taylor; Steenbrugge, Jonas; Lu, Rebecca; Kinkhabwala, Anika; Marchon, Bruno; Meyer, Evelyne; Mokres, Lucia

    2017-01-01

    Overuse of antibiotics is a major problem in the treatment of bovine mastitis, and antibiotic treatment is frequently non-curative, thus alternative treatments are necessary. The primary aim of this study was to evaluate the efficacy of a purified phage cocktail for treatment of bovine Staphylococcus aureus mastitis in a well-defined mouse model. Candidate phages were selected based on their in vitro performance and subsequently processed into an optimally composed phage cocktail. The highest scoring phages were further tested for efficacy and resistance suppression in broth and raw milk, with and without supplemental IgG. As these in vitro results displayed significant decreases in CFU, the cocktail was purified for testing in vivo . Lactating mice were intramammarily inoculated with S. aureus N305 (ATCC 29740), a clinical bovine mastitis isolate commonly used for experimental infection of dairy cows. The phage cocktail was applied via the same route 4 h post-inoculation. Treated mammary glands were graded for gross pathological appearance and excised for bacterial and phage load quantification as well as histopathology. Observation of gross macroscopic and histopathological changes and CFU quantification demonstrated that the phage cocktail treatment significantly improved mastitis pathology and decreased bacterial counts. Phage PFU quantification indicated that the tested phage cocktail treatment was able to maintain high intramammary phage titers without spreading systemically. The in vivo results complement the in vitro data and support our concept of phage therapy as an innovative alternative or supplementation therapy to antibiotics for the treatment of bovine mastitis.

  11. DeltaPhage--a novel helper phage for high-valence pIX phagemid display.

    PubMed

    Nilssen, Nicolay R; Frigstad, Terje; Pollmann, Sylvie; Roos, Norbert; Bogen, Bjarne; Sandlie, Inger; Løset, Geir Å

    2012-09-01

    Phage display has been instrumental in discovery of novel binding peptides and folded domains for the past two decades. We recently reported a novel pIX phagemid display system that is characterized by a strong preference for phagemid packaging combined with low display levels, two key features that support highly efficient affinity selection. However, high diversity in selected repertoires are intimately coupled to high display levels during initial selection rounds. To incorporate this additional feature into the pIX display system, we have developed a novel helper phage termed DeltaPhage that allows for high-valence display on pIX. This was obtained by inserting two amber mutations close to the pIX start codon, but after the pVII translational stop, conditionally inactivating the helper phage encoded pIX. Until now, the general notion has been that display on pIX is dependent on wild-type complementation, making high-valence display unachievable. However, we found that DeltaPhage does facilitate high-valence pIX display when used with a non-suppressor host. Here, we report a side-by-side comparison with pIII display, and we find that this novel helper phage complements existing pIX phagemid display systems to allow both low and high-valence display, making pIX display a complete and efficient alternative to existing pIII phagemid display systems.

  12. Pyocin-sensitivity testing as a method of typing Pseudomonas aeruginosa: use of "phage-free" preparations of pyocin.

    PubMed

    Rampling, A; Whitby, J L; Wildy, P

    1975-11-01

    A method for pyocin-sensitivity typing by means of "phage-free" preparations of pyocin is described. The method was tested on 227 isolates of P. aeruginosa, collected from 34 different foci of infection in hospitals in the British Isles and the results were compared with those for combined serological and phage typing of all strains and pyocin production of 105 of the isolates. It is concluded that pyocin-sensitivity typing is a simple and reliable method giving a high degree of discrimination, comparable to that of combined serological and phage typing, and it is suitable for use in routine hospital laboratories.

  13. Evaluating risk factors for endemic human Salmonella Enteritidis infections with different phage types in Ontario, Canada using multinomial logistic regression and a case-case study approach

    PubMed Central

    2012-01-01

    Background Identifying risk factors for Salmonella Enteritidis (SE) infections in Ontario will assist public health authorities to design effective control and prevention programs to reduce the burden of SE infections. Our research objective was to identify risk factors for acquiring SE infections with various phage types (PT) in Ontario, Canada. We hypothesized that certain PTs (e.g., PT8 and PT13a) have specific risk factors for infection. Methods Our study included endemic SE cases with various PTs whose isolates were submitted to the Public Health Laboratory-Toronto from January 20th to August 12th, 2011. Cases were interviewed using a standardized questionnaire that included questions pertaining to demographics, travel history, clinical symptoms, contact with animals, and food exposures. A multinomial logistic regression method using the Generalized Linear Latent and Mixed Model procedure and a case-case study design were used to identify risk factors for acquiring SE infections with various PTs in Ontario, Canada. In the multinomial logistic regression model, the outcome variable had three categories representing human infections caused by SE PT8, PT13a, and all other SE PTs (i.e., non-PT8/non-PT13a) as a referent category to which the other two categories were compared. Results In the multivariable model, SE PT8 was positively associated with contact with dogs (OR=2.17, 95% CI 1.01-4.68) and negatively associated with pepper consumption (OR=0.35, 95% CI 0.13-0.94), after adjusting for age categories and gender, and using exposure periods and health regions as random effects to account for clustering. Conclusions Our study findings offer interesting hypotheses about the role of phage type-specific risk factors. Multinomial logistic regression analysis and the case-case study approach are novel methodologies to evaluate associations among SE infections with different PTs and various risk factors. PMID:23057531

  14. Basics of Antibody Phage Display Technology.

    PubMed

    Ledsgaard, Line; Kilstrup, Mogens; Karatt-Vellatt, Aneesh; McCafferty, John; Laustsen, Andreas H

    2018-06-09

    Antibody discovery has become increasingly important in almost all areas of modern medicine. Different antibody discovery approaches exist, but one that has gained increasing interest in the field of toxinology and antivenom research is phage display technology. In this review, the lifecycle of the M13 phage and the basics of phage display technology are presented together with important factors influencing the success rates of phage display experiments. Moreover, the pros and cons of different antigen display methods and the use of naïve versus immunized phage display antibody libraries is discussed, and selected examples from the field of antivenom research are highlighted. This review thus provides in-depth knowledge on the principles and use of phage display technology with a special focus on discovery of antibodies that target animal toxins.

  15. Demand for abortion and post abortion care in Ibadan, Nigeria

    PubMed Central

    2014-01-01

    Background While induced abortion is considered to be illegal and socially unacceptable in Nigeria, it is still practiced by many women in the country. Poor family planning and unsafe abortion practices have daunting effects on maternal health. For instance, Nigeria is on the verge of not meeting the Millennium development goals on maternal health due to high maternal mortality ratio, estimated to be about 630 maternal deaths per 100,000 live births. Recent evidences have shown that a major factor in this trend is the high incidence of abortion in the country. The objective of this paper is, therefore, to investigate the factors determining the demand for abortion and post-abortion care in Ibadan city of Nigeria. Methods The study employed data from a hospital-based/exploratory survey carried out between March to September 2010. Closed ended questionnaires were administered to a sample of 384 women of reproductive age from three hospitals within the Ibadan metropolis in South West Nigeria. However, only 308 valid responses were received and analysed. A probit model was fitted to determine the socioeconomic factors that influence demand for abortion and post-abortion care. Results The results showed that 62% of respondents demanded for abortion while 52.3% of those that demanded for abortion received post-abortion care. The findings again showed that income was a significant determinant of abortion and post-abortion care demand. Women with higher income were more likely to demand abortion and post-abortion care. Married women were found to be less likely to demand for abortion and post-abortion care. Older women were significantly less likely to demand for abortion and post-abortion care. Mothers’ education was only statistically significant in determining abortion demand but not post-abortion care demand. Conclusion The findings suggest that while abortion is illegal in Nigeria, some women in the Ibadan city do abort unwanted pregnancies. The consequence of this

  16. Demand for abortion and post abortion care in Ibadan, Nigeria.

    PubMed

    Awoyemi, Bosede O; Novignon, Jacob

    2014-01-01

    While induced abortion is considered to be illegal and socially unacceptable in Nigeria, it is still practiced by many women in the country. Poor family planning and unsafe abortion practices have daunting effects on maternal health. For instance, Nigeria is on the verge of not meeting the Millennium development goals on maternal health due to high maternal mortality ratio, estimated to be about 630 maternal deaths per 100,000 live births. Recent evidences have shown that a major factor in this trend is the high incidence of abortion in the country. The objective of this paper is, therefore, to investigate the factors determining the demand for abortion and post-abortion care in Ibadan city of Nigeria. The study employed data from a hospital-based/exploratory survey carried out between March to September 2010. Closed ended questionnaires were administered to a sample of 384 women of reproductive age from three hospitals within the Ibadan metropolis in South West Nigeria. However, only 308 valid responses were received and analysed. A probit model was fitted to determine the socioeconomic factors that influence demand for abortion and post-abortion care. The results showed that 62% of respondents demanded for abortion while 52.3% of those that demanded for abortion received post-abortion care. The findings again showed that income was a significant determinant of abortion and post-abortion care demand. Women with higher income were more likely to demand abortion and post-abortion care. Married women were found to be less likely to demand for abortion and post-abortion care. Older women were significantly less likely to demand for abortion and post-abortion care. Mothers' education was only statistically significant in determining abortion demand but not post-abortion care demand. The findings suggest that while abortion is illegal in Nigeria, some women in the Ibadan city do abort unwanted pregnancies. The consequence of this in the absence of proper post-abortion

  17. [Peptide phage display in biotechnology and biomedicine].

    PubMed

    Kuzmicheva, G A; Belyavskaya, V A

    2016-07-01

    To date peptide phage display is one of the most common combinatorial methods used for identifying specific peptide ligands. Phage display peptide libraries containing billions different clones successfully used for selection of ligands with high affinity and selectivity toward wide range of targets including individual proteins, bacteria, viruses, spores, different kind of cancer cells and variety of nonorganic targets (metals, alloys, semiconductors etc.) Success of using filamentous phage in phage display technologies relays on the robustness of phage particles and a possibility to genetically modify its DNA to construct new phage variants with novel properties. In this review we are discussing characteristics of the most known non-commercial peptide phage display libraries of different formats (landscape libraries in particular) and their successful applications in several fields of biotechnology and biomedicine: discovery of peptides with diagnostic values against different pathogens, discovery and using of peptides recognizing cancer cells, trends in using of phage display technologies in human interactome studies, application of phage display technologies in construction of novel nano materials.

  18. Dual genetically encoded phage-displayed ligands.

    PubMed

    Mohan, Kritika; Weiss, Gregory A

    2014-05-15

    M13 bacteriophage display presents polypeptides as fusions to phage coat proteins. Such phage-displayed ligands offer useful reagents for biosensors. Here, we report a modified phage propagation protocol for the consistent and robust display of two different genetically encoded ligands on the major coat protein, P8. The results demonstrate that the phage surface reaches a saturation point for maximum peptide display. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Membrane insertion and assembly of epitope-tagged gp9 at the tip of the M13 phage.

    PubMed

    Ploss, Martin; Kuhn, Andreas

    2011-09-26

    Filamentous M13 phage extrude from infected Escherichia coli with a tip structure composed of gp7 and gp9. This tip structure is extended by the assembly of the filament composed of the major coat protein gp8. Finally, gp3 and gp6 terminate the phage structure at the proximal end. Up to now, gp3 has been the primary tool for phage display technology. However, gp7, gp8 and gp9 could also be used for phage display and these phage particles should bind to two different or more surfaces when the modified coat proteins are combined. Therefore, we tested here if the amino-terminal end of gp9 can be modified and whether the modified portion is exposed and detectable on the M13 phage particles. The amino-terminal region of gp9 was modified by inserting short sequences that encode antigenic epitopes. We show here that the modified gp9 proteins correctly integrate into the membrane using the membrane insertase YidC exposing the modified epitope into the periplasm. The proteins are then efficiently assembled onto the phage particles. Also extensions up to 36 amino acid residues at the amino-terminal end of gp9 did not interfere with membrane integration and phage assembly. The exposure of the antigenic tags on the phage was visualised with immunogold labelling by electron microscopy and verified by dot blotting with antibodies to the tags. Our results suggest that gp9 at the phage tip is suitable for the phage display technology. The modified gp9 can be supplied in trans from a plasmid and fully complements M13 phage with an amber mutation in gene 9. The modified phage tip is very well accessible to antibodies.

  20. Membrane insertion and assembly of epitope-tagged gp9 at the tip of the M13 phage

    PubMed Central

    2011-01-01

    Background Filamentous M13 phage extrude from infected Escherichia coli with a tip structure composed of gp7 and gp9. This tip structure is extended by the assembly of the filament composed of the major coat protein gp8. Finally, gp3 and gp6 terminate the phage structure at the proximal end. Up to now, gp3 has been the primary tool for phage display technology. However, gp7, gp8 and gp9 could also be used for phage display and these phage particles should bind to two different or more surfaces when the modified coat proteins are combined. Therefore, we tested here if the amino-terminal end of gp9 can be modified and whether the modified portion is exposed and detectable on the M13 phage particles. Results The amino-terminal region of gp9 was modified by inserting short sequences that encode antigenic epitopes. We show here that the modified gp9 proteins correctly integrate into the membrane using the membrane insertase YidC exposing the modified epitope into the periplasm. The proteins are then efficiently assembled onto the phage particles. Also extensions up to 36 amino acid residues at the amino-terminal end of gp9 did not interfere with membrane integration and phage assembly. The exposure of the antigenic tags on the phage was visualised with immunogold labelling by electron microscopy and verified by dot blotting with antibodies to the tags. Conclusions Our results suggest that gp9 at the phage tip is suitable for the phage display technology. The modified gp9 can be supplied in trans from a plasmid and fully complements M13 phage with an amber mutation in gene 9. The modified phage tip is very well accessible to antibodies. PMID:21943062

  1. Abortion - surgical

    MedlinePlus

    Suction curettage; Surgical abortion; Elective abortion - surgical; Therapeutic abortion - surgical ... Surgical abortion involves dilating the opening to the uterus (cervix) and placing a small suction tube into the uterus. ...

  2. Expression of a novel P22 ORFan gene reveals the phage carrier state in Salmonella typhimurium.

    PubMed

    Cenens, William; Mebrhatu, Mehari T; Makumi, Angella; Ceyssens, Pieter-Jan; Lavigne, Rob; Van Houdt, Rob; Taddei, François; Aertsen, Abram

    2013-01-01

    We discovered a novel interaction between phage P22 and its host Salmonella Typhimurium LT2 that is characterized by a phage mediated and targeted derepression of the host dgo operon. Upon further investigation, this interaction was found to be instigated by an ORFan gene (designated pid for phage P22 encoded instigator of dgo expression) located on a previously unannotated moron locus in the late region of the P22 genome, and encoding an 86 amino acid protein of 9.3 kDa. Surprisingly, the Pid/dgo interaction was not observed during strict lytic or lysogenic proliferation of P22, and expression of pid was instead found to arise in cells that upon infection stably maintained an unintegrated phage chromosome that segregated asymmetrically upon subsequent cell divisions. Interestingly, among the emerging siblings, the feature of pid expression remained tightly linked to the cell inheriting this phage carrier state and became quenched in the other. As such, this study is the first to reveal molecular and genetic markers authenticating pseudolysogenic development, thereby exposing a novel mechanism, timing, and populational distribution in the realm of phage-host interactions.

  3. Bacteria between protists and phages: from antipredation strategies to the evolution of pathogenicity.

    PubMed

    Brüssow, Harald

    2007-08-01

    Bacteriophages and protists are major causes of bacterial mortality. Genomics suggests that phages evolved well before eukaryotic protists. Bacteria were thus initially only confronted with phage predators. When protists evolved, bacteria were caught between two types of predators. One successful antigrazing strategy of bacteria was the elaboration of toxins that would kill the grazer. The released cell content would feed bystander bacteria. I suggest here that, to fight grazing protists, bacteria teamed up with those phage predators that concluded at least a temporary truce with them in the form of lysogeny. Lysogeny was perhaps initially a resource management strategy of phages that could not maintain infection chains. Subsequently, lysogeny might have evolved into a bacterium-prophage coalition attacking protists, which became a food source for them. When protists evolved into multicellular animals, the lysogenic bacteria tracked their evolving food source. This hypothesis could explain why a frequent scheme of bacterial pathogenicity is the survival in phagocytes, why a significant fraction of bacterial pathogens have prophage-encoded virulence genes, and why some virulence factors of animal pathogens are active against unicellular eukaryotes. Bacterial pathogenicity might thus be one playing option of the stone-scissor-paper game played between phages-bacteria-protists, with humans getting into the crossfire.

  4. Isolation and characterization of a novel, T7-like phage against Aeromonas veronii.

    PubMed

    Anand, Taruna; Bera, Bidhan Ch; Virmani, Nitin; Vaid, Rajesh Kumar; Vashisth, Medhavi; Tripathi, Bhupendra Nath

    2018-02-01

    A virulent Aeromonas veronii biovar sobria and the corresponding novel, lytic bacteriophage (VTCCBPA5) were isolated from village pond water. The phage was found to belong to family Podoviridae. PCR analysis of major capsid protein gene confirmed its classification to T7-like genus. The protein profiling by SDS-PAGE indicated the major structural protein to be ~ 45 kDa. The phage (VTCCBPA5) is host specific and is stable over a range of pH (6-10) and temperatures (4-45 °C). On the basis of restriction endonuclease analysis combined with prediction mapping, it was observed to vary significantly from previously reported podophages of Aeromonas sp., viz. phiAS7 and Ahp1. The phylogenetic analysis on the basis of PCR-amplified segment of DNA polymerase gene of phage revealed it being an outgroup from podophages of Klebsiella sp. and Pseudomonas sp. though a small internal fragment (359 bp) showed the highest identity (77%) with Vibrio sp. phages. Thus, this is the first report of a novel Podoviridae phage against A. veronii. It expands the assemblage of podophages against Aeromonas sp. and BPA5 could be potentially useful in biocontrol of environmentally acquired Aeromonas veronii infections.

  5. Corruption of phage display libraries by target-unrelated clones: diagnosis and countermeasures.

    PubMed

    Thomas, William D; Golomb, Miriam; Smith, George P

    2010-12-15

    Phage display is used to discover peptides or proteins with a desired target property-most often, affinity for a target selector molecule. Libraries of phage clones displaying diverse surface peptides are subject to a selection process designed to enrich for the target behavior and subsequently propagated to restore phage numbers. A recurrent problem is enrichment of clones, called target-unrelated phages or peptides (TUPs), that lack the target behavior. Many TUPs are propagation related; they have mutations conferring a growth advantage and are enriched during the propagations accompanying selection. Unlike other filamentous phage libraries, fd-tet-based libraries are relatively resistant to propagation-related TUP corruption. Their minus-strand origin is disrupted by a large cassette that simultaneously confers resistance to tetracycline and imposes a rate-limiting growth defect that cannot be bypassed with simple mutations. Nonetheless, a new type of propagation-related TUP emerged in the output of in vivo selections from an fd-tet library. The founding clone had a complex rearrangement that restored the minus-strand origin while retaining tetracycline resistance. The rearrangement involved two recombination events, one with a contaminant having a wild-type minus-strand origin. The founder's infectivity advantage spread by simple recombination to clones displaying different peptides. We propose measures for minimizing TUP corruption. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. Prevalence of parvovirus B19 specific antibody in pregnant women with spontaneous abortion.

    PubMed

    Rahbar, Nahid; Vali Zadeh, Saeid; Ghorbani, Raheb; Kheradmand, Pegah

    2015-01-01

    Human parvovirus B19 is a very common viral infection especially in school-aged children. The infection during pregnancy can affect the fetus due to lack of mother's immunity. Although, there is still no evidence of fetal teratogenic effects with parvovirus B19, but non-immune fetal hydrops and abortion may be caused by vertical transmission of the virus during pregnancy. This study was aimed to assess the prevalence of parvovirus B19-specific antibody (IgM) in pregnant women who had a spontaneous abortion. This cross-sectional study was carried out in all pregnant women who referred due to a spontaneous abortion. All demographic information such as age, occupation, and gestational age, last history of abortion, gravity, and presence of children below the age of six was recorded and a blood sample was provided for all the women. Then, the blood samples were tested to assay parvovirus B19-specific antibody (IgM) by EuroImmune ELISA kit. Among 94 pregnant women with the mean age of 28.4 years who had a spontaneous abortion, parvovirus B19 specific antibody (IgM) was detected in 17 participants (18.1%). Meanwhile, 14 women (14.9%) were suspected for presence of the antibody in their blood sample. There was no significant difference between the presence of antibody and age of pregnant women, occupation, gestational age, number of previous abortion, presence of children below the age of six and number of pregnancy. These findings revealed that a high percentage of pregnant women are probably non-immune against parvovirus B19, and also there might be a number of spontaneous abortions in which parvovirus infection caused fetal death.  However, more studies are needed to prove the absolute role of parvovirus B19 in these abortions.

  7. Genetic modifications to temperate Enterococcus faecalis phage ϕEf11 that abolish the establishment of lysogeny and sensitivity to repressor, and increase host range and productivity of lytic infection

    PubMed Central

    Zhang, H.; Fouts, D. E.; DePew, J.

    2013-01-01

    ϕEf11 is a temperate bacteriophage originally isolated by induction from a lysogenic Enterococcus faecalis strain recovered from an infected root canal, and the ϕEf11 prophage is widely disseminated among strains of E. faecalis. Because E. faecalis has emerged as a significant opportunistic human pathogen, we were interested in examining the genes and regulatory sequences predicted to be critical in the establishment/maintenance of lysogeny by ϕEf11 as a first step in the construction of the genome of a virulent, highly lytic phage that could be used in treating serious E. faecalis infections. Passage of ϕEf11 in E. faecalis JH2-2 yielded a variant that produced large, extensively spreading plaques in lawns of indicator cells, and elevated phage titres in broth cultures. Genetic analysis of the cloned virus producing the large plaques revealed that the variant was a recombinant between ϕEf11 and a defective ϕFL1C-like prophage located in the E. faecalis JH2-2 chromosome. The recombinant possessed five ORFs of the defective ϕFL1C-like prophage in place of six ORFs of the ϕEf11 genome. Deletion of the putative lysogeny gene module (ORFs 31–36) and replacement of the putative cro promoter from the recombinant phage genome with a nisin-inducible promoter resulted in no loss of virus infectivity. The genetic construct incorporating all the aforementioned ϕEf11 genomic modifications resulted in the generation of a variant that was incapable of lysogeny and insensitive to repressor, rendering it virulent and highly lytic, with a notably extended host range. PMID:23579685

  8. Induced abortion.

    PubMed

    2017-06-01

    Abortion is common. Data on abortion rates are inexact but can be used to explore trends. Globally, the estimated rate in the period 2010-2014 was 35 abortions per 1000 women (aged 15-44 years), five points less than the rate of 40 for the period 1990-1994. Abortion laws vary around the world but are generally more restrictive in developing countries. Restrictive laws do not necessarily deter women from seeking abortion but often lead to unsafe practice with significant mortality and morbidity. While a legal framework for abortion is a prerequisite for availability, many laws, which are not evidence based, restrict availability and delay access. Abortion should be available in the interests of public health and any legal framework should be as permissive as possible in order to promote access. In the absence of legal access, harm reduction strategies are needed to reduce abortion-related mortality and morbidity. Abortion can be performed surgically (in the first trimester, by manual or electric vacuum aspiration) or with medication: both are safe and effective. Cervical priming facilitates surgery and reduces the risk of incomplete abortion. Diagnosis of incomplete abortion should be made on clinical grounds, not by ultrasound. Septic abortion is a common cause of maternal death almost always following unsafe abortion and thus largely preventable. While routine follow-up after abortion is unnecessary, all women should be offered a contraceptive method immediately after the abortion. This, together with improved education and other interventions, may succeed in reducing unintended pregnancy. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Phage-Induced Expression of CRISPR-Associated Proteins is Revealed by Shotgun Proteomics in Streptococcus thermophilus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Young, Jacque C; Dill, Brian; Pan, Chongle

    The CRISPR/Cas system, comprised of clustered regularly interspaced short palindromic repeats along with their associated (Cas) proteins, protects bacteria and archaea from viral predation and invading nucleic acids. While the mechanism of action for this acquired immunity is currently under investigation, the response of Cas protein expression to phage infection has yet to be elucidated. In this study, we employed shotgun proteomics to measure the global proteome expression in a model system for studying the CRISPR/Cas response: infection of S. thermophilus DGCC7710 with phage 2972. Host and viral proteins were simultaneously measured following inoculation at two different multiplicities of infectionmore » and across various time points using two-dimensional liquid chromatography tandem mass spectroscopy. Thirty-seven out of forty predicted viral proteins were detected, including all proteins of the structural virome and viral effector proteins. In total, 1,013 of 2,079 predicted S. thermophilus proteins were detected, facilitating the monitoring of host protein synthesis changes in response to virus infection. Importantly, Cas proteins from all four CRISPR loci in the S. thermophilus DGCC7710 genome were detected, including loci previously thought to be inactive. Many Cas proteins were found to be constitutively expressed, but several demonstrated increased abundance during peak infection, including the Cas9 proteins from the CRISPR1 and CRISPR3 loci, which are key players in the interference phase of the CRISPR/Cas response. Altogether, these results provide novel insights into the proteomic response of S. thermophilus, specifically CRISPR-associated proteins, upon phage 2972 infection.« less

  10. Profiles of women presenting for abortions in Singapore: focus on teenage abortions and late abortions.

    PubMed

    Lim, Limin; Wong, Hungchew; Yong, Euleong; Singh, Kuldip

    2012-02-01

    Teenage abortions predispose women to adverse pregnancy outcomes in subsequent pregnancies such as anemia, stillbirths, preterm deliveries and low birth weight babies. We aim to profile the women presenting for abortions in our institution and determine risk factors for late presentation for abortions. In this retrospective cohort study, all women who underwent an abortion at the National University Hospital, Singapore, from 2005 to 2009 were recruited. Data was obtained from a prepared questionnaire during the mandatory pre-abortion counseling sessions. Profiles of women aged <20 years were compared with those ≥ 20 years old using Chi-square test if the assumptions for Chi-square test were met; otherwise, Fisher's exact test was carried out. Logistic regression was used to investigate the risk factors for second trimester termination of pregnancy. 2109 women presented for induced abortions, of which 1998 had single abortion throughout the course of the study. The mean age of women with single abortion was 29.1 years (sd 7). In the group of women with single abortion, 182 (9.1%) were teenage abortions. In contrast to women ≥ 20 years of age, pregnant teenagers were more likely not to have used any contraception (51.1% vs. 25.2%) and more likely to present late for abortions (39.6% vs. 15.9%). Other risk factors for late presentation for abortions include Malay ethnicity, singlehood, nulliparity and lack of prior usage of contraception. Teenagers are more likely to have no prior contraceptive usage and to present late for abortions. Lack of proper sexual education and awareness of contraceptive measures may have a major contributory factor to such a trend in teenage abortions. Recommendations have been made in order to curb this societal problem. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  11. Characterization of the temperate phage vB_RleM_PPF1 and its site-specific integration into the Rhizobium leguminosarum F1 genome.

    PubMed

    Halmillawewa, Anupama P; Restrepo-Córdoba, Marcela; Perry, Benjamin J; Yost, Christopher K; Hynes, Michael F

    2016-02-01

    Bacteriophages may play an important role in regulating population size and diversity of the root nodule symbiont Rhizobium leguminosarum, as well as participating in horizontal gene transfer. Although phages that infect this species have been isolated in the past, our knowledge of their molecular biology, and especially of genome composition, is extremely limited, and this lack of information impacts on the ability to assess phage population dynamics and limits potential agricultural applications of rhizobiophages. To help address this deficit in available sequence and biological information, the complete genome sequence of the Myoviridae temperate phage PPF1 that infects R. leguminosarum biovar viciae strain F1 was determined. The genome is 54,506 bp in length with an average G+C content of 61.9 %. The genome contains 94 putative open reading frames (ORFs) and 74.5 % of these predicted ORFs share homology at the protein level with previously reported sequences in the database. However, putative functions could only be assigned to 25.5 % (24 ORFs) of the predicted genes. PPF1 was capable of efficiently lysogenizing its rhizobial host R. leguminosarum F1. The site-specific recombination system of the phage targets an integration site that lies within a putative tRNA-Pro (CGG) gene in R. leguminosarum F1. Upon integration, the phage is capable of restoring the disrupted tRNA gene, owing to the 50 bp homologous sequence (att core region) it shares with its rhizobial host genome. Phage PPF1 is the first temperate phage infecting members of the genus Rhizobium for which a complete genome sequence, as well as other biological data such as the integration site, is available.

  12. FURTHER OBSERVATIONS ON THE MECHANISM OF PHAGE ACTION

    PubMed Central

    Krueger, A. P.; Scribner, E. J.; Brown, B. B.

    1946-01-01

    1. The reaction between an antistaphlycoccal phage and the homologous bacterium has been studied, applying the following experimental technics not used in earlier work reported from this laboratory: (a) Both the activity assay and the plaque count were utilized for determining [phage]. (b) Sampling was done at short intervals; i.e., every 0.1 hour. (c) Extracellular phage was separated from the cell-bound fraction by a filtration procedure permitting passage of < 95 per cent of free phage. 2. Using these technics, the reaction was followed: (a) with pH maintained at 6.10 and temperature at 28°C. to slow the process; (b) with pH maintained at 7.2 and temperature at 36°C. 3. In addition separate experiments were performed on the sorption of phage by bacteria at 30°, 23°, and 0°C. 4. At pH 6.10 and 28°C. the phage-bacterium reaction proceeds in the following sequence: (a) There is an initial phase of rapid logarithmic sorption of phage to susceptible cells, during which the total phage activity and the plaque numbers in the mixtures remain constant. (b) When 90 per cent of the phage has been bound, there is a sudden very rapid increase in phage activity not paralleled by an increase in plaques; i.e., phage is formed intracellularly, but is retained within cellular confines. (c) After a further drop in the extracellular phage fraction there occurs a pronounced increase in the total phage plaque count not accompanied by any increase in total activity. This indicates a redistribution of phage formed intracellularly. At the same time there is a rise in the extracellular phage curves (both activity and plaque). (d) With the concentrations of phage and bacteria used in the experiment carried out at pH 6.1 and 28°C. there are two further increments in [phage]act. before massive lysis begins. (e) During terminal lysis there are sharp rises in the curves for [total phage]plaq., [extracellular phage]act., and [extracellular phage]plaq.. (f) Immediately after the

  13. Phage display—A powerful technique for immunotherapy

    PubMed Central

    Bazan, Justyna; Całkosiński, Ireneusz; Gamian, Andrzej

    2012-01-01

    One of the most effective molecular diversity techniques is phage display. This technology is based on a direct linkage between phage phenotype and its encapsulated genotype, which leads to presentation of molecule libraries on the phage surface. Phage display is utilized in studying protein-ligand interactions, receptor binding sites and in improving or modifying the affinity of proteins for their binding partners. Generating monoclonal antibodies and improving their affinity, cloning antibodies from unstable hybridoma cells and identifying epitopes, mimotopes and functional or accessible sites from antigens are also important advantages of this technology. Techniques originating from phage display have been applied to transfusion medicine, neurological disorders, mapping vascular addresses and tissue homing of peptides. Phages have been applicable to immunization therapies, which may lead to development of new tools used for treating autoimmune and cancer diseases. This review describes the phage display technology and presents the recent advancements in therapeutic applications of phage display. PMID:22906939

  14. Wide host range and strong lytic activity of Staphylococcus aureus lytic phage Stau2.

    PubMed

    Hsieh, Sue-Er; Lo, Hsueh-Hsia; Chen, Shui-Tu; Lee, Mong-Chuan; Tseng, Yi-Hsiung

    2011-02-01

    In searching for an alternative antibacterial agent against multidrug-resistant Staphylococcus aureus, we have isolated and characterized a lytic staphylophage, Stau2. It possesses a double-stranded DNA genome estimated to be about 134.5 kb and a morphology resembling that of members of the family Myoviridae. With an estimated latency period of 25 min and a burst size of 100 PFU/infected cell, propagation of Stau2 in liquid culture gave a lysate of ca. 6 × 10(10) PFU/ml. It was stable at pH 5 to 13 in normal saline at room temperature for at least 4 weeks and at -85°C for more than 2 years, while 1 × 10(9) out of 2 × 10(12) PFU/ml retained infectivity after 36 months at 4°C. Stau2 could lyse 80% of the S. aureus isolates (164/205) obtained from hospitals in Taiwan, with complete lysis of most of the isolates tested within 3 h; however, it was an S. aureus-specific phage because no lytic infection could be found in the coagulase-negative staphylococci tested. Its host range among S. aureus isolates was wider than that of polyvalent phage K (47%), which can also lyse many other staphylococcal species. Experiments with mice demonstrated that Stau2 could provide 100% protection from lethal infection when a multiplicity of infection of 10 was administered immediately after a challenge with S. aureus S23. Considering these results, Stau2 could be considered at least as a candidate for topical phage therapy or an additive in the food industry.

  15. Portrait of a viral infection: The infection cycle of Vibrio vulnificus phage VvAW1 visualized through plaque assay, electron microscopy, and proteomics

    NASA Astrophysics Data System (ADS)

    Clah, K. E. Y.; Nigro, O. D.; Miranda, J.; Schvarcz, C.; Culley, A.; Saito, M. A.; Steward, G.

    2016-02-01

    The bacterium Vibrio vulnificus is an opportunistic human pathogen that thrives in warm brackish waters. Viral infection is one of several mechanisms influencing the population dynamics of this bacterium in the natural environment. V. vulnificus-specific viruses have been isolated; however, the details of their infection cycle have not been reported. As a result, our current understanding of the interaction between the bacterium and its viruses in the environment is limited. To better understand the infection process, a strain of V. vulnificus (V93D1V) and its bacteriophage, Vibrio phage VvAW1, were isolated from the estuarine waters of the Ala Wai Canal, HI. A time-series infection experiment was conducted with the virus-host pair in which samples were collected every ten minutes for eighty minutes post-infection for analysis by plaque assay, electron microscopy, and proteomics. Using electron microscopy, visibly infected bacteria were observed forty minutes after the introduction of the virus, signaling the end of the eclipse period. The peak of infection occurred at seventy minutes with an average viral load of 78 viruses per bacterium. The percentage of visibly infected bacteria reached a maximum just prior to a rise in free viruses in the culture, indicating the end of the latent period. The percentage of infected cells that lysed was low and there was little effect on the bacterial population growth rate. Analysis of the proteome revealed that protein expression patterns, in particular capsid and other structural proteins, closely follow the timing of the observed infection cycle. Together, these analyses provided the first detailed view of a viral infection in a highly lethal aquatic bacterium. The apparent temperate nature of this virus suggests that it can be a source of mortality to V. vulnificus, but has evolved to avoid total destruction of its host by complete lysis, a characteristic that helps ensure its replication in subsequent generations.

  16. Lytic and inhibition responses to bacteriophages among marine bacteria, with special reference to the origin of phage-host systems

    NASA Astrophysics Data System (ADS)

    Moebus, K.

    1983-12-01

    The results of phage-host cross-reaction tests reported by Moebus & Nattkemper (1981) were re-examined using serially diluted bacteriophage suspensions to elicit the actual type of reaction between the bacteria and phage lysates tested. More than 1450 phage-host systems were studied at 25 °C incubation temperature. Among the nearly 300 phage strains used, 29 were identified as temperate ones. In about 65 % of the phage-host systems bacteriophage propagation was indicated by plaque formation. The remaining systems were characterized by the “inhibition” reaction of bacteria to phage lysates indicated by homogenously reduced bacterial growth within the test area without production of progeny phages. Since crude phage lysates had to be used, it remains obscure whether agents other than infective phage particles (defective ones or bacteriocins) caused this reaction. Among 269 systems of the inhibition type which were also tested at 5° and 15 °C, 54 were observed to propagate phages at one of or both the lower temperatures. Plaques produced at 15 °C with several phage-host systems were found to yield only few progeny phages which generally could not be propagated to produce high-titer phage stocks. With one system temperature-sensitive phage mutants were isolated. The probability of inhibition reactions occurring was found to be higher with phage-host systems isolated east of the Azores than with systems derived from the western Atlantic. With systems from the last mentioned area the proportion of inhibition versus lytic responses of bacteria to phages was observed to increase with the distance between the stations where both parts of the systems were derived. The latter findings are discussed in view of the assumption that bacterial and bacteriophage populations undergo genetic changes while being transported from west to east.

  17. Thioredoxin is required for filamentous phage assembly.

    PubMed Central

    Russel, M; Model, P

    1985-01-01

    Sequence comparisons show that the fip gene product of Escherichia coli, which is required for filamentous phage assembly, is thioredoxin. Thioredoxin serves as a cofactor for reductive processes in many cell types and is a constituent of phage T7 DNA polymerase. The fip-1 mutation makes filamentous phage and T7 growth temperature sensitive in cells that carry it. The lesion lies within a highly conserved thioredoxin active site. Thioredoxin reductase (NADPH), as well as thioredoxin, is required for efficient filamentous phage production. Mutant phages defective in phage gene I are particularly sensitive to perturbations in the fip-thioredoxin system. A speculative model is presented in which thioredoxin reductase, thioredoxin, and the gene I protein interact to drive an engine for filamentous phage assembly. Images PMID:3881756

  18. Phage-protease-peptide: a novel trifecta enabling multiplex detection of viable bacterial pathogens.

    PubMed

    Alcaine, S D; Tilton, L; Serrano, M A C; Wang, M; Vachet, R W; Nugen, S R

    2015-10-01

    Bacteriophages represent rapid, readily targeted, and easily produced molecular probes for the detection of bacterial pathogens. Molecular biology techniques have allowed researchers to make significant advances in the bioengineering of bacteriophage to further improve speed and sensitivity of detection. Despite their host specificity, bacteriophages have not been meaningfully leveraged in multiplex detection of bacterial pathogens. We propose a proof-of-principal phage-based scheme to enable multiplex detection. Our scheme involves bioengineering bacteriophage to carry a gene for a specific protease, which is expressed during infection of the target cell. Upon lysis, the protease is released to cleave a reporter peptide, and the signal detected. Here we demonstrate the successful (i) modification of T7 bacteriophage to carry tobacco etch virus (TEV) protease; (ii) expression of TEV protease by Escherichia coli following infection by our modified T7, an average of 2000 units of protease per phage are produced during infection; and (iii) proof-of-principle detection of E. coli in 3 h after a primary enrichment via TEV protease activity using a fluorescent peptide and using a designed target peptide for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF MS) analysis. This proof-of-principle can be translated to other phage-protease-peptide combinations to enable multiplex bacterial detection and readily adopted on multiple platforms, like MALDI-TOF MS or fluorescent readers, commonly found in labs.

  19. Abortion and subsequent excretion of chlamydiae from the reproductive tract of sheep during estrus.

    PubMed Central

    Papp, J R; Shewen, P E; Gartley, C J

    1994-01-01

    Chlamydia psittaci serovar 1 infection in pregnant sheep typically causes abortion or the birth of weak lambs. Eight sheep that experienced chlamydia-induced abortion during their first pregnancy were successfully rebred yearly for the past 2 years. Chlamydia-specific lipopolysaccharide was detectable for approximately 3 weeks in vaginal swabs taken from the experimentally infected sheep following abortion. There was no evidence of chlamydiae in vaginal, placental, or neonatal samples obtained immediately after each subsequent successful pregnancy. Sera collected from the experimentally infected sheep had persistent, high antibody levels to C. psittaci, suggesting continued exposure of the immune system to the organism. Examination of vaginal specimens obtained during various stages of the estrus cycle revealed detectable levels of chlamydiae only when the animal was near ovulation. Chlamydiae were not detected in swabs from sheep that did not experience abortion. Enhanced chlamydial excretion during the periovulation period of sheep may provide sufficient stimulation of the immune system to account for the persistent antibody response. Furthermore, the association between estrus and chlamydial shedding has important implications for transmission of infection to other ewes during breeding. PMID:8063395

  20. The genome and structural proteome of YuA, a new Pseudomonas aeruginosa phage resembling M6.

    PubMed

    Ceyssens, Pieter-Jan; Mesyanzhinov, Vadim; Sykilinda, Nina; Briers, Yves; Roucourt, Bart; Lavigne, Rob; Robben, Johan; Domashin, Artem; Miroshnikov, Konstantin; Volckaert, Guido; Hertveldt, Kirsten

    2008-02-01

    Pseudomonas aeruginosa phage YuA (Siphoviridae) was isolated from a pond near Moscow, Russia. It has an elongated head, encapsulating a circularly permuted genome of 58,663 bp, and a flexible, noncontractile tail, which is terminally and subterminally decorated with short fibers. The YuA genome is neither Mu- nor lambda-like and encodes 78 gene products that cluster in three major regions involved in (i) DNA metabolism and replication, (ii) host interaction, and (iii) phage particle formation and host lysis. At the protein level, YuA displays significant homology with phages M6, phiJL001, 73, B3, DMS3, and D3112. Eighteen YuA proteins were identified as part of the phage particle by mass spectrometry analysis. Five different bacterial promoters were experimentally identified using a promoter trap assay, three of which have a sigma54-specific binding site and regulate transcription in the genome region involved in phage particle formation and host lysis. The dependency of these promoters on the host sigma54 factor was confirmed by analysis of an rpoN mutant strain of P. aeruginosa PAO1. At the DNA level, YuA is 91% identical to the recently (July 2007) annotated phage M6 of the Lindberg typing set. Despite this level of DNA homology throughout the genome, both phages combined have 15 unique genes that do not occur in the other phage. The genome organization of both phages differs substantially from those of the other known Pseudomonas-infecting Siphoviridae, delineating them as a distinct genus within this family.

  1. Marine Phages As Tracers: Effects of Size, Morphology, and Physico-Chemical Surface Properties on Transport in a Porous Medium.

    PubMed

    Ghanem, Nawras; Kiesel, Bärbel; Kallies, René; Harms, Hauke; Chatzinotas, Antonis; Wick, Lukas Y

    2016-12-06

    Although several studies examined the transport of viruses in terrestrial systems only few studies exist on the use of marine phages (i.e., nonterrestrial viruses infecting marine host bacteria) as sensitively detectable microbial tracers for subsurface colloid transport and water flow. Here, we systematically quantified and compared for the first time the effects of size, morphology and physicochemical surface properties of six marine phages and two coliphages (MS2, T4) on transport in sand-filled percolated columns. Phage-sand interactions were described by colloidal filtration theory and the extended Derjaguin-Landau-Verwey-Overbeek approach (XDLVO), respectively. The phages belonged to different families and comprised four phages never used in transport studies (i.e., PSA-HM1, PSA-HP1, PSA-HS2, and H3/49). Phage transport was influenced by size, morphology and hydrophobicity in an approximate order of size > hydrophobicity ≥ morphology. Two phages PSA-HP1, PSA-HS2 (Podoviridae and Siphoviridae) exhibited similar mass recovery as commonly used coliphage MS2 and were 7-fold better transported than known marine phage vB_PSPS-H40/1. Differing properties of the marine phages may be used to trace transport of indigenous viruses, natural colloids or anthropogenic nanomaterials and, hence, contribute to better risk analysis. Our results underpin the potential role of marine phages as microbial tracer for transport of colloidal particles and water flow.

  2. EFFECT OF SODIUM CHLORIDE ON STAPHYLOCOCCUS-PHAGE RELATIONSHIPS

    PubMed Central

    West, B.; Kelly, Florene C.; Shields, Doris A.

    1963-01-01

    West, B. (University of Oklahoma Medical Center, Oklahoma City), Florene C. Kelly, and Doris A. Shields. Effect of sodium chloride on staphylococcus-phage relationships. J. Bacteriol. 86:773–780. 1963.—Phage patterns of 21 phage-propagating strains of staphylococci on medium with high NaCl content appeared to be an expression of the staphylococcal cells, as well as of the salt tolerance of the phages. Serological group A phages, previously found to be NaCl-tolerant in the free state, were capable of lysing susceptible staphylococci on 3, 7.5, and 10% NaCl Trypticase Soy Agar. None of the other phages tested was active when the medium contained 7.5 and 10% NaCl. Increasing the NaCl content of the medium rarely resulted in nonspecific reactions; rather the effect was, generally, a narrowing of the phage spectrum of the cells, with persistence in the phage pattern of the phage, or phages, which were propagated on the cells being tested. Although NaCl tolerance of the phages was the chief limiting factor of phage activity in the presence of 7.5 and 10% NaCl, reactions on salt medium also depended on the degree of susceptibility of cells to phage on routine typing medium and to certain other unexplained factors. In some instances, under the influence of increased NaCl, significant lysis at 1000 RTD was replaced by thinning of growth (inhibition), with or without the presence of plaques. Conversely, certain phage-cell combinations, which gave inhibition at 1000 RTD on standard medium produced some degree of lysis when the NaCl concentration was increased. Studies of phage 81 and its propagating strain showed that replication of phage occurred in 10% NaCl medium, although adsorption diminished as salt concentration was increased, and the time required to reach maximal lytic activity was delayed. PMID:14066474

  3. Control of Pierce's Disease by Phage

    PubMed Central

    Das, Mayukh; Bhowmick, Tushar Suvra; Ahern, Stephen J.; Young, Ry; Gonzalez, Carlos F.

    2015-01-01

    Pierce’s Disease (PD) of grapevines, caused by Xylella fastidiosa subsp. fastidiosa (Xf), is a limiting factor in the cultivation of grapevines in the US. There are presently no effective control methods to prevent or treat PD. The therapeutic and prophylactic efficacy of a phage cocktail composed of four virulent (lytic) phages was evaluated for control of PD. Xf levels in grapevines were significantly reduced in therapeutically or prophylactically treated grapevines. PD symptoms ceased to progress one week post-therapeutic treatment and symptoms were not observed in prophylactically treated grapevines. Cocktail phage levels increased in grapevines in the presence of the host. No in planta phage-resistant Xf isolates were obtained. Moreover, Xf mutants selected for phage resistance in vitro did not cause PD symptoms. Our results indicate that phages have great potential for biocontrol of PD and other economically important diseases caused by Xylella. PMID:26107261

  4. Reduced disease in black abalone following mass mortality: phage therapy and natural selection

    PubMed Central

    Friedman, Carolyn S.; Wight, Nathan; Crosson, Lisa M.; VanBlaricom, Glenn R.; Lafferty, Kevin D.

    2014-01-01

    Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS). Natural recovery on San Nicolas Island (SNI) of Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO) had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv) reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus) coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host–parasite relationships will better enable us to manage declining populations. PMID:24672512

  5. Reduced disease in black abalone following mass mortality: phage therapy and natural selection.

    PubMed

    Friedman, Carolyn S; Wight, Nathan; Crosson, Lisa M; Vanblaricom, Glenn R; Lafferty, Kevin D

    2014-01-01

    Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS). Natural recovery on San Nicolas Island (SNI) of Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO) had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv) reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus) coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host-parasite relationships will better enable us to manage declining populations.

  6. Reduced disease in black abalone following mass mortality: Phage therapy and natural selection

    USGS Publications Warehouse

    VanBlaricom, Glenn R.

    2014-01-01

    Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS). Natural recovery on San Nicolas Island (SNI) of Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO) had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv) reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus) coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host–parasite relationships will better enable us to manage declining populations.

  7. Abundant and Diverse Clustered Regularly Interspaced Short Palindromic Repeat Spacers in Clostridium difficile Strains and Prophages Target Multiple Phage Types within This Pathogen

    PubMed Central

    Hargreaves, Katherine R.; Flores, Cesar O.; Lawley, Trevor D.

    2014-01-01

    ABSTRACT Clostridium difficile is an important human-pathogenic bacterium causing antibiotic-associated nosocomial infections worldwide. Mobile genetic elements and bacteriophages have helped shape C. difficile genome evolution. In many bacteria, phage infection may be controlled by a form of bacterial immunity called the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system. This uses acquired short nucleotide sequences (spacers) to target homologous sequences (protospacers) in phage genomes. C. difficile carries multiple CRISPR arrays, and in this paper we examine the relationships between the host- and phage-carried elements of the system. We detected multiple matches between spacers and regions in 31 C. difficile phage and prophage genomes. A subset of the spacers was located in prophage-carried CRISPR arrays. The CRISPR spacer profiles generated suggest that related phages would have similar host ranges. Furthermore, we show that C. difficile strains of the same ribotype could either have similar or divergent CRISPR contents. Both synonymous and nonsynonymous mutations in the protospacer sequences were identified, as well as differences in the protospacer adjacent motif (PAM), which could explain how phages escape this system. This paper illustrates how the distribution and diversity of CRISPR spacers in C. difficile, and its prophages, could modulate phage predation for this pathogen and impact upon its evolution and pathogenicity. PMID:25161187

  8. Evaluation of DNA extraction protocols for Brucella abortus pcr detection in aborted fetuses or calves born from cows experimentally infected with strain 2308

    PubMed Central

    Matrone, M.; Keid, L.B.; Rocha, V.C.M.; Vejarano, M.P.; Ikuta, C.Y.; Rodriguez, C.A.R.; Ferreira, F.; Dias, R.A.; Ferreira Neto, J.S

    2009-01-01

    The objective of the present study was to improve the detection of B. abortus by PCR in organs of aborted fetuses from infected cows, an important mechanism to find infected herds on the eradication phase of the program. So, different DNA extraction protocols were compared, focusing the PCR detection of B. abortus in clinical samples collected from aborted fetuses or calves born from cows challenged with the 2308 B. abortus strain. Therefore, two gold standard groups were built based on classical bacteriology, formed from: 32 lungs (17 positives), 26 spleens (11 positives), 23 livers (8 positives) and 22 bronchial lymph nodes (7 positives). All samples were submitted to three DNA extraction protocols, followed by the same amplification process with the primers B4 and B5. From the accumulated results for organ, the proportion of positives for the lungs was higher than the livers (p=0.04) or bronchial lymph nodes (p=0.004) and equal to the spleens (p=0.18). From the accumulated results for DNA extraction protocol, the proportion of positives for the Boom protocol was bigger than the PK (p< 0.0001) and GT (p=0.0004). There was no difference between the PK and GT protocols (p=0.5). Some positive samples from the classical bacteriology were negative to the PCR and vice-versa. Therefore, the best strategy for B. abortus detection in the organs of aborted fetuses or calves born from infected cows is the use, in parallel, of isolation by classical bacteriology and the PCR, with the DNA extraction performed by the Boom protocol. PMID:24031391

  9. Phage displayed peptide recognizing porcine aminopeptidase N is a potent small molecule inhibitor of PEDV entry

    USDA-ARS?s Scientific Manuscript database

    Three phage-displayed peptides designated H, S and F that recognize porcine aminopeptidase N (pAPN), the cellular receptor of porcine transmissible gastroenteritis virus (TGEV) were able to inhibit cell infection by TGEV. These same peptides had no inhibitory effects on infection of Vero cells by po...

  10. Pros and cons of phage therapy

    PubMed Central

    Loc-Carrillo, Catherine

    2011-01-01

    Many publications list advantages and disadvantages associated with phage therapy, which is the use of bacterial viruses to combat populations of nuisance or pathogenic bacteria. The goal of this commentary is to discuss many of those issues in a single location. In terms of “Pros,” for example, phages can be bactericidal, can increase in number over the course of treatment, tend to only minimally disrupt normal flora, are equally effective against antibiotic-sensitive and antibiotic-resistant bacteria, often are easily discovered, seem to be capable of disrupting bacterial biofilms, and can have low inherent toxicities. In addition to these assets, we consider aspects of phage therapy that can contribute to its safety, economics, or convenience, but in ways that are perhaps less essential to the phage potential to combat bacteria. For example, autonomous phage transfer between animals during veterinary application could provide convenience or economic advantages by decreasing the need for repeated phage application, but is not necessarily crucial to therapeutic success. We also consider possible disadvantages to phage use as antibacterial agents. These “Cons,” however, tend to be relatively minor. PMID:22334867

  11. Leptospirosa pomona Abortion Storm in a Cattle Herd in Saskatchewan

    PubMed Central

    Kingscote, Barbara F.; Wilson, D.

    1986-01-01

    Abortions occurred in 18% of 131 beef cows and heifers during two months, on a farm in southern Saskatchewan. The losses began two weeks after acute febrile illness and agalactia in a dairy cow to which the beef herd had been exposed. A diagnosis of Leptospira interrogans serovar pomona infection was made on the basis of serology in cows and the finding of leptospires in fetal tissues by fluorescent antibody test. Tentative diagnosis of infectious bovine rhinotracheitis delayed treatment and prophylaxis until infection attained high intensity in the herd and severe losses to the farmer occurred. Abortions ceased after vaccination against pomona and oxytetracycline treatment of pregnant cows, although chronic debility followed the acute phase of the disease in some cows. Recrudescence of infection was suspected four months later, when acute agalactia occurred in one cow and debility in calves and cows was recurring. Pomona infection was not proven, but dihydrostreptomycin treatment and revaccination were applied to the whole herd. Seroconversion and IgM antibody continued to indicate a persistent source of infection and susceptibility in a minority of the population one year after onset. The source of the original infection is believed to have been a carrier beef cow, or a dairy cow which was leptospiruric at the time of contact with the beef herd. With the exception of one aborted calf, no evidence of pomona infection was found outside the farm, in cattle or wild mammals tested serologically within a radius of 30 km, during one year following the outbreak. PMID:17422717

  12. Misperceptions about the risks of abortion in women presenting for abortion.

    PubMed

    Wiebe, Ellen R; Littman, Lisa; Kaczorowski, Janusz; Moshier, Erin L

    2014-03-01

    Misinformation about the risks and sequelae of abortion is widespread. The purpose of this study was to examine whether women having an abortion who believe that there should be restrictions to abortion (i.e., that some other women should not be allowed to have an abortion) also believe this misinformation about the health risks associated with abortion. We carried out a cross-sectional survey of women presenting consecutively for an abortion at an urban abortion clinic in Vancouver, British Columbia, between February and September 2012. Of 1008 women presenting for abortion, 978 completed questionnaires (97% response rate), and 333 of these (34%) favoured abortion restrictions. More women who favoured restrictions believed that the health risk of an abortion was the same as or greater than the health risk of childbirth (84.2% vs. 65.6%, P < 0.001), that abortion caused mental health problems (39.1% vs. 28.3%, P < 0.001), and that abortion caused infertility (41.7% vs. 21.9%, P < 0.001). Using multivariate logistic regression analyses, believing that abortion should not be restricted was found to be a significantly correlated with correct answers about health risks, mental health problems, and infertility. Misinformed beliefs about the risks of abortion are common among women having an abortion. Women presenting for abortion who favoured restrictions to abortion have more misperceptions about abortion risks than women who favour no restrictions.

  13. Phages of Lactobacillus casei/paracasei: response to environmental factors and interaction with collection and commercial strains.

    PubMed

    Capra, M L; Quiberoni, A; Reinheimer, J

    2006-02-01

    To investigate the influence of several environmental factors on the viability and cell-adsorption for two Lactobacillus casei/paracasei bacteriophages (PL-1 and J-1). Both phages showed a remarkably high specificity of species, sharing similar host spectra. Two phages and four sensitive strains were used to conform five phage/strain systems. Each showed a particular behaviour (burst size: ranging from 32 to 160 PFU/infective centre; burst time: 120-240 min and latent time: 5-90 min). For both phages, the viability was not significantly affected from pH 4 to 11 (room temperature) and from pH 5 to 10 (37 degrees C). Adsorption rates were not influenced by calcium ions, but decreased after the thermal inactivation of cells. Adsorption rates were high between 0 and 50 degrees C with maximum values at 30 degrees C and pH 6. System PL-1/Lact. paracasei A showed noticeable differences in comparison with the others, being times required to reach 90% of adsorption of 4 h and lower than 45 min, respectively. The data obtained in this work demonstrated that environmental parameters can influence the viability and cell adsorption rates of Lact. casei/paracasei phages. The extent of this influence was phage dependent. This work contributes to the enlargement of the currently scarce knowledge of phages of probiotic bacteria.

  14. Genomic and molecular analysis of phage CMP1 from Clavibacter michiganensis subspecies michiganensis

    PubMed Central

    Wittmann, Johannes; Gartemann, Karl-Heinz; Eichenlaub, Rudolf

    2011-01-01

    Bacteriophage CMP1 is a member of the Siphoviridae family that infects specifically the plant-pathogen Clavibacter michiganensis subsp. michiganensis. The linear double- stranded DNA is terminally redundant and not circularly permuted. The complete nucleotide sequence of the bacteriophage CMP1 genome consists of 58,652 bp including the terminal redundant ends of 791 bp. The G+C content of the phage (57%) is significantly lower than that of its host (72.66%). 74 potential open reading frames were identified and annotated by different bioinformatic tools. Two large clusters which encode the early and the late functions could be identified which are divergently transcribed. There are only a few hypothetical gene products with conserved domains and significant similarity to sequences from the databases. Functional analyses confirmed the activity of four gene products, an endonuclease, an exonuclease, a single-stranded DNA binding protein and a thymidylate synthase. Partial genomic sequences of CN77, a phage of Clavibacter michiganensis subsp. nebraskensis, revealed a similar genome structure and significant similarities on the level of deduced amino acid sequences. An endolysin with peptidase activity has been identified for both phages, which may be good tools for disease control of tomato plants against Clavibacter infections. PMID:21687530

  15. Genomic and molecular analysis of phage CMP1 from Clavibacter michiganensis subspecies michiganensis.

    PubMed

    Wittmann, Johannes; Gartemann, Karl-Heinz; Eichenlaub, Rudolf; Dreiseikelmann, Brigitte

    2011-01-01

    Bacteriophage CMP1 is a member of the Siphoviridae family that infects specifically the plant-pathogen Clavibacter michiganensis subsp. michiganensis. The linear double- stranded DNA is terminally redundant and not circularly permuted. The complete nucleotide sequence of the bacteriophage CMP1 genome consists of 58,652 bp including the terminal redundant ends of 791 bp. The G+C content of the phage (57%) is significantly lower than that of its host (72.66%). 74 potential open reading frames were identified and annotated by different bioinformatic tools. Two large clusters which encode the early and the late functions could be identified which are divergently transcribed. There are only a few hypothetical gene products with conserved domains and significant similarity to sequences from the databases. Functional analyses confirmed the activity of four gene products, an endonuclease, an exonuclease, a single-stranded DNA binding protein and a thymidylate synthase. Partial genomic sequences of CN77, a phage of Clavibacter michiganensis subsp. nebraskensis, revealed a similar genome structure and significant similarities on the level of deduced amino acid sequences. An endolysin with peptidase activity has been identified for both phages, which may be good tools for disease control of tomato plants against Clavibacter infections.

  16. INACTIVATION AND REACTIVATION OF B. MEGATHERIUM PHAGE

    PubMed Central

    Northrop, John H.

    1955-01-01

    Preparation of Reversibly Inactivated (R.I.) Phage.— If B. megatherium phage (of any type, or in any stage of purification) is suspended in dilute salt solutions at pH 5–6, it is completely inactivated; i.e., it does not form plaques, or give rise to more phage when mixed with a sensitive organism (Northrop, 1954). The inactivation occurs when the phage is added to the dilute salt solution. If a suspension of the inactive phage in pH 7 peptone is titrated to pH 5 and allowed to stand, the activity gradually returns. The inactivation is therefore reversible. Properties of R.I. Phage.— The R.I. phage is adsorbed by sensitive cells at about the same rate as the active phage. It kills the cells, but no active phage is produced. The R.I. phage therefore has the properties of phage "ghosts" (Herriott, 1951) or of colicines (Gratia, 1925), or phage inactivated by ultraviolet light (Luria, 1947). The R.I. phage is sedimented in the centrifuge at the same rate as active phage. It is therefore about the same size as the active phage. The R.I. phage is most stable in pH 7, 5 per cent peptone, and may be kept in this solution for weeks at 0°C. The rate of digestion of R.I. phage by trypsin, chymotrypsin, or desoxyribonuclease is about the same as that of active phage (Northrop, 1955 a). Effect of Various Substances on the Formation of R.I. Phage.— There is an equilibrium between R.I. phage and active phage. The R.I. form is the stable one in dilute salt solution, pH 5 to 6.5 and at low temperature (<20°C.). At pH >6.5, in dilute salt solution, the R.I. phage changes to the active form. The cycle, active ⇌ inactive phage, may be repeated many times at 0°C. by changing the pH of the solution back and forth between pH 7 and pH 6. Irreversible inactivation is caused by distilled water, some heavy metals, concentrated urea or quanidine solutions, and by l-arginine. Reversible inactivation is prevented by all salts tested (except those causing irreversible inactivation

  17. Satellite phage TLCφ enables toxigenic conversion by CTX phage through dif site alteration.

    PubMed

    Hassan, Faizule; Kamruzzaman, M; Mekalanos, John J; Faruque, Shah M

    2010-10-21

    Bacterial chromosomes often carry integrated genetic elements (for example plasmids, transposons, prophages and islands) whose precise function and contribution to the evolutionary fitness of the host bacterium are unknown. The CTXφ prophage, which encodes cholera toxin in Vibrio cholerae, is known to be adjacent to a chromosomally integrated element of unknown function termed the toxin-linked cryptic (TLC). Here we report the characterization of a TLC-related element that corresponds to the genome of a satellite filamentous phage (TLC-Knφ1), which uses the morphogenesis genes of another filamentous phage (fs2φ) to form infectious TLC-Knφ1 phage particles. The TLC-Knφ1 phage genome carries a sequence similar to the dif recombination sequence, which functions in chromosome dimer resolution using XerC and XerD recombinases. The dif sequence is also exploited by lysogenic filamentous phages (for example CTXφ) for chromosomal integration of their genomes. Bacterial cells defective in the dimer resolution often show an aberrant filamentous cell morphology. We found that acquisition and chromosomal integration of the TLC-Knφ1 genome restored a perfect dif site and normal morphology to V. cholerae wild-type and mutant strains with dif(-) filamentation phenotypes. Furthermore, lysogeny of a dif(-) non-toxigenic V. cholerae with TLC-Knφ1 promoted its subsequent toxigenic conversion through integration of CTXφ into the restored dif site. These results reveal a remarkable level of cooperative interactions between multiple filamentous phages in the emergence of the bacterial pathogen that causes cholera.

  18. Access to abortion: what women want from abortion services.

    PubMed

    Wiebe, Ellen R; Sandhu, Supna

    2008-04-01

    Whether Canadian physicians can refuse to refer women for abortion and whether private clinics can charge for abortions are matters of controversy. We sought to identify barriers to access for women seeking therapeutic abortion and to have them identify what they considered to be most important about access to abortion services. Women presenting for abortion over a two-month period at two free-standing abortion clinics, one publicly funded and the other private, were invited to participate in the study. Phase I of the study involved administration of a questionnaire seeking information about demographics, perceived barriers to access to abortion, and what the women wanted from abortion services. Phase II involved semi-structured interviews of a convenience sample of women to record their responses to questions about access. Responses from Phase I questionnaires were compared between the two clinics, and qualitative analysis was performed on the interview responses. Of 423 eligible women, 402 completed questionnaires, and of 45 women approached, 39 completed interviews satisfactorily. Women received information about abortion services from their physicians (60.0%), the Internet (14.8%), a telephone directory (7.8%), friends or family (5.3%), or other sources (12.3%). Many had negative experiences in gaining access. The most important issue regarding access was the long wait time; the second most important issue was difficulty in making appointments. In the private clinic, 85% of the women said they were willing to pay for shorter wait times, compared with 43.5% in the public clinic. Physicians who failed to refer patients for abortion or provide information about obtaining an abortion caused distress and impeded access for a significant minority of women requesting an abortion. Management of abortion services should be prioritized to reflect what women want: particularly decreased wait times for abortion and greater ease and convenience in booking appointments

  19. The effect of inhibition of host MreB on the infection of thermophilic phage GVE2 in high temperature environment.

    PubMed

    Jin, Min; Chen, Yanjiang; Xu, Chenxi; Zhang, Xiaobo

    2014-04-28

    In eukaryotes, the manipulation of the host actin cytoskeleton is a necessary strategy for viral pathogens to invade host cells. Increasing evidence indicates that the actin homolog MreB of bacteria plays key roles in cell shape formation, cell polarity, cell wall biosynthesis, and chromosome segregation. However, the role of bacterial MreB in the bacteriophage infection is not extensively investigated. To address this issue, in this study, the MreB of thermophilic Geobacillus sp. E263 from a deep-sea hydrothermal field was characterized by inhibiting the MreB polymerization and subsequently evaluating the bacteriophage GVE2 infection. The results showed that the host MreB played important roles in the bacteriophage infection at high temperature. After the host cells were treated with small molecule drug A22 or MP265, the specific inhibitors of MreB polymerization, the adsorption of GVE2 and the replication of GVE2 genome were significantly repressed. The confocal microscopy data revealed that MreB facilitated the GVE2 infection by inducing the polar distribution of virions during the phage infection. Our study contributed novel information to understand the molecular events of the host in response to bacteriophage challenge and extended our knowledge about the host-virus interaction in deep-sea vent ecosystems.

  20. The effect of inhibition of host MreB on the infection of thermophilic phage GVE2 in high temperature environment

    PubMed Central

    Jin, Min; Chen, Yanjiang; Xu, Chenxi; Zhang, Xiaobo

    2014-01-01

    In eukaryotes, the manipulation of the host actin cytoskeleton is a necessary strategy for viral pathogens to invade host cells. Increasing evidence indicates that the actin homolog MreB of bacteria plays key roles in cell shape formation, cell polarity, cell wall biosynthesis, and chromosome segregation. However, the role of bacterial MreB in the bacteriophage infection is not extensively investigated. To address this issue, in this study, the MreB of thermophilic Geobacillus sp. E263 from a deep-sea hydrothermal field was characterized by inhibiting the MreB polymerization and subsequently evaluating the bacteriophage GVE2 infection. The results showed that the host MreB played important roles in the bacteriophage infection at high temperature. After the host cells were treated with small molecule drug A22 or MP265, the specific inhibitors of MreB polymerization, the adsorption of GVE2 and the replication of GVE2 genome were significantly repressed. The confocal microscopy data revealed that MreB facilitated the GVE2 infection by inducing the polar distribution of virions during the phage infection. Our study contributed novel information to understand the molecular events of the host in response to bacteriophage challenge and extended our knowledge about the host-virus interaction in deep-sea vent ecosystems. PMID:24769758

  1. Incidence of Induced Abortion and Post-Abortion Care in Tanzania

    PubMed Central

    Keogh, Sarah C.; Kimaro, Godfather; Muganyizi, Projestine; Philbin, Jesse; Kahwa, Amos; Ngadaya, Esther; Bankole, Akinrinola

    2015-01-01

    Background Tanzania has one of the highest maternal mortality ratios in the world, and unsafe abortion is one of its leading causes. Yet little is known about its incidence. Objectives To provide the first ever estimates of the incidence of unsafe abortion in Tanzania, at the national level and for each of the 8 geopolitical zones (7 in Mainland plus Zanzibar). Methods A nationally representative survey of health facilities was conducted to determine the number of induced abortion complications treated in facilities. A survey of experts on abortion was conducted to estimate the likelihood of women experiencing complications and obtaining treatment. These surveys were complemented with population and fertility data to obtain abortion numbers, rates and ratios, using the Abortion Incidence Complications Methodology. Results In Tanzania, women obtained just over 405,000 induced abortions in 2013, for a national rate of 36 abortions per 1,000 women age 15–49 and a ratio of 21 abortions per 100 live births. For each woman treated in a facility for induced abortion complications, 6 times as many women had an abortion but did not receive care. Abortion rates vary widely by zone, from 10.7 in Zanzibar to 50.7 in the Lake zone. Conclusions The abortion rate is similar to that of other countries in the region. Variations by zone are explained mainly by differences in fertility and contraceptive prevalence. Measures to reduce the incidence of unsafe abortion and associated maternal mortality include expanding access to post-abortion care and contraceptive services to prevent unintended pregnancies. PMID:26361246

  2. Incidence of Induced Abortion and Post-Abortion Care in Tanzania.

    PubMed

    Keogh, Sarah C; Kimaro, Godfather; Muganyizi, Projestine; Philbin, Jesse; Kahwa, Amos; Ngadaya, Esther; Bankole, Akinrinola

    2015-01-01

    Tanzania has one of the highest maternal mortality ratios in the world, and unsafe abortion is one of its leading causes. Yet little is known about its incidence. To provide the first ever estimates of the incidence of unsafe abortion in Tanzania, at the national level and for each of the 8 geopolitical zones (7 in Mainland plus Zanzibar). A nationally representative survey of health facilities was conducted to determine the number of induced abortion complications treated in facilities. A survey of experts on abortion was conducted to estimate the likelihood of women experiencing complications and obtaining treatment. These surveys were complemented with population and fertility data to obtain abortion numbers, rates and ratios, using the Abortion Incidence Complications Methodology. In Tanzania, women obtained just over 405,000 induced abortions in 2013, for a national rate of 36 abortions per 1,000 women age 15-49 and a ratio of 21 abortions per 100 live births. For each woman treated in a facility for induced abortion complications, 6 times as many women had an abortion but did not receive care. Abortion rates vary widely by zone, from 10.7 in Zanzibar to 50.7 in the Lake zone. The abortion rate is similar to that of other countries in the region. Variations by zone are explained mainly by differences in fertility and contraceptive prevalence. Measures to reduce the incidence of unsafe abortion and associated maternal mortality include expanding access to post-abortion care and contraceptive services to prevent unintended pregnancies.

  3. Bacteriophages and their derivatives for the treatment and control of food-producing animal infections.

    PubMed

    Carvalho, Carla; Costa, Ana Rita; Silva, Filipe; Oliveira, Ana

    2017-09-01

    Nowadays, the world is facing an increasing emergence of antibiotic resistant bacteria. Simultaneously, the banning of some existing antibiotics and the lack of development of new antimicrobials have created an urgent need to find new alternatives against animal infections. Bacteriophages (phages) are naturally occurring predators of bacteria, ubiquitous in the environment, with high host specificity and harmless to animals. For these reasons, phages and their derivatives are being considered valuable antimicrobial alternatives and an opportunity to reduce the current use of antibiotics in agri-food production, increasing animal productivity and providing environmental protection. Furthermore, the possibility of combining phage genetic material with foreign genes encoding peptides of interest has enabled their use as vaccine delivery tools. In this case, besides bacterial infections, they might be used to prevent viral infections. This review explores current data regarding advances on the use of phages and phage-encoded proteins, such as endolysins, exolysins and depolymerases, either for therapeutic or prophylactic applications, in animal husbandry. The use of recombinant phage-derived particles or genetically modified phages, including phage vaccines, will also be reviewed.

  4. Phage or foe: an insight into the impact of viral predation on microbial communities.

    PubMed

    Fernández, Lucía; Rodríguez, Ana; García, Pilar

    2018-05-01

    Since their discovery, bacteriophages have been traditionally regarded as the natural enemies of bacteria. However, recent advances in molecular biology techniques, especially data from "omics" analyses, have revealed that the interplay between bacterial viruses and their hosts is far more intricate than initially thought. On the one hand, we have become more aware of the impact of viral predation on the composition and genetic makeup of microbial communities thanks to genomic and metagenomic approaches. Moreover, data obtained from transcriptomic, proteomic, and metabolomic studies have shown that responses to phage predation are complex and diverse, varying greatly depending on the bacterial host, phage, and multiplicity of infection. Interestingly, phage exposure may alter different phenotypes, including virulence and biofilm formation. The complexity of the interactions between microbes and their viral predators is also evidenced by the link between quorum-sensing signaling pathways and bacteriophage resistance. Overall, new data increasingly suggests that both temperate and virulent phages have a positive effect on the evolution and adaptation of microbial populations. From this perspective, further research is still necessary to fully understand the interactions between phage and host under conditions that allow co-existence of both populations, reflecting more accurately the dynamics in natural microbial communities.

  5. The diagnosis of salmonella abortion in cattle with particular reference to Salmonella dublin. A review.

    PubMed Central

    Hinton, M.

    1977-01-01

    The diagnosis of abortion in cattle caused by Salmonella dublin depends upon the isolation of the organism from either the products of conception, uterine discharges, vaginal mucus or milk together with serological evidence of active infection. S. dublin may be isolated when an active or a latent carrier cow abourts but in these cases an active infection will not be demonstrable. The retrospective identification of a case of S. dublin abortion may prove difficult as excretion of the organism is usually transient and the serum agglutinating antibodies frequently fall to low titres soon after the abortion. PMID:328768

  6. Targeting Leishmania major parasite with peptides derived from a combinatorial phage display library.

    PubMed

    Rhaiem, Rafik Ben; Houimel, Mehdi

    2016-07-01

    Cutaneous leishmaniasis (CL) is a global problem caused by intracellular protozoan pathogens of the genus Leishmania for which there are no suitable vaccine or chemotherapy options. Thus, de novo identification of small molecules binding to the Leishmania parasites by direct screening is a promising and appropriate alternative strategy for the development of new drugs. In this study, we used a random linear hexapeptide library fused to the gene III protein of M13 filamentous bacteriophage to select binding peptides to metacyclic promastigotes from a highly virulent strain of Leishmania major (Zymodeme MON-25; MHOM/TN/94/GLC94). After four rounds of stringent selection and amplification, polyclonal and monoclonal phage-peptides directed against L. major metacyclic promastigotes were assessed by ELISA, and the optimal phage-peptides were grown individually and characterized for binding to L. major by monoclonal phage ELISA. The DNA of 42 phage-peptides clones was amplified by PCR, sequenced, and their amino acid sequences deduced. Six different peptide sequences were obtained with frequencies of occurrence ranging from 2.3% to 85.7%. The biological effect of the peptides was assessed in vitro on human monocytes infected with L. major metacyclic promastigotes, and in vivo on susceptible parasite-infected BALB/c mice. The development of cutaneous lesions in the right hind footpads of infected mice after 13 weeks post-infection showed a protection rate of 81.94% with the injected peptide P2. Moreover, Western blots revealed that the P2 peptide interacted with the major surface protease gp63, a protein of 63kDa molecular weight. Moreover, bioinformatics were used to predict the interaction between peptides and the major surface molecule of the L. major. The molecular docking showed that the P2 peptide has the minimum interaction energy and maximum shape complimentarity with the L. major gp63 active site. Our study demonstrated that the P2 peptide occurs at high frequency

  7. Dual host specificity of phage SP6 is facilitated by tailspike rotation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tu, Jiagang

    Bacteriophage SP6 exhibits dual-host adsorption specificity. The SP6 tailspikes are recognized as important in host range determination but the mechanisms underlying dual host specificity are unknown. Cryo-electron tomography and sub-tomogram classification were used to analyze the SP6 virion with a particular focus on the interaction of tailspikes with host membranes. The SP6 tail is surrounded by six V-shaped structures that interconnect in forming a hand-over-hand hexameric garland. Each V-shaped structure consists of two trimeric tailspike proteins: gp46 and gp47, connected through the adaptor protein gp37. SP6 infection of Salmonella enterica serovars Typhimurium and Newport results in distinguishable changes in tailspikemore » orientation, providing the first direct demonstration how tailspikes can confer dual host adsorption specificity. SP6 also infects S. Typhimurium strains lacking O antigen; in these infections tailspikes have no apparent specific role and the phage tail must therefore interact with a distinct host receptor to allow infection. - Highlights: •Cryo-electron tomography reveals the structural basis for dual host specificity. •Sub-tomogram classification reveals distinct orientations of the tailspikes during infection of different hosts. •Tailspike-adaptor modules rotate as they bind different O antigens. •In the absence of any O antigen, tailspikes bind weakly and without specificity to LPS. •Interaction of the phage tail with LPS is essential for infection.« less

  8. Protein and Antibody Engineering by Phage Display.

    PubMed

    Frei, J C; Lai, J R

    2016-01-01

    Phage display is an in vitro selection technique that allows for the rapid isolation of proteins with desired properties including increased affinity, specificity, stability, and new enzymatic activity. The power of phage display relies on the phenotype-to-genotype linkage of the protein of interest displayed on the phage surface with the encoding DNA packaged within the phage particle, which allows for selective enrichment of library pools and high-throughput screening of resulting clones. As an in vitro method, the conditions of the binding selection can be tightly controlled. Due to the high-throughput nature, rapidity, and ease of use, phage display is an excellent technological platform for engineering antibody or proteins with enhanced properties. Here, we describe methods for synthesis, selection, and screening of phage libraries with particular emphasis on designing humanizing antibody libraries and combinatorial scanning mutagenesis libraries. We conclude with a brief section on troubleshooting for all stages of the phage display process. © 2016 Elsevier Inc. All rights reserved.

  9. Protein and Antibody Engineering by Phage Display

    PubMed Central

    Frei, J.C.; Lai, J.R.

    2017-01-01

    Phage display is an in vitro selection technique that allows for the rapid isolation of proteins with desired properties including increased affinity, specificity, stability, and new enzymatic activity. The power of phage display relies on the phenotype-to-genotype linkage of the protein of interest displayed on the phage surface with the encoding DNA packaged within the phage particle, which allows for selective enrichment of library pools and high-throughput screening of resulting clones. As an in vitro method, the conditions of the binding selection can be tightly controlled. Due to the high-throughput nature, rapidity, and ease of use, phage display is an excellent technological platform for engineering antibody or proteins with enhanced properties. Here, we describe methods for synthesis, selection, and screening of phage libraries with particular emphasis on designing humanizing antibody libraries and combinatorial scanning mutagenesis libraries. We conclude with a brief section on troubleshooting for all stages of the phage display process. PMID:27586328

  10. Phages of life - the path to pharma.

    PubMed

    Forde, Amanda; Hill, Colin

    2018-02-01

    Bacteriophage (phage) therapy has encountered both enthusiasm and scepticism in the past century. New antimicrobial strategies against lethal pathogens are now a top priority for the World Health Organization, and although compassionate use of phages recently met with significant success, regulated clinical interventions seem unlikely in the near future. The hundredth anniversary of their discovery seems an appropriate time for a revival of phage therapy, particularly as the dilemma of antibiotic resistance grows. Phages are ubiquitous in the environment, on our food and in and on our bodies. Their influence on human health is currently being evaluated, and in this mini-review, we examine data from recent metagenomic studies that propose a role for phages in the structure of the microbiome and in health and disease. We assess evidence for phages as vehicles for gene transfer in the context of antibiotic resistance and discuss challenges and opportunities along the critical path from phage discovery to a patient-focused pharmaceutical intervention. © 2017 The British Pharmacological Society.

  11. Wide Host Range and Strong Lytic Activity of Staphylococcus aureus Lytic Phage Stau2▿

    PubMed Central

    Hsieh, Sue-Er; Lo, Hsueh-Hsia; Chen, Shui-Tu; Lee, Mong-Chuan; Tseng, Yi-Hsiung

    2011-01-01

    In searching for an alternative antibacterial agent against multidrug-resistant Staphylococcus aureus, we have isolated and characterized a lytic staphylophage, Stau2. It possesses a double-stranded DNA genome estimated to be about 134.5 kb and a morphology resembling that of members of the family Myoviridae. With an estimated latency period of 25 min and a burst size of 100 PFU/infected cell, propagation of Stau2 in liquid culture gave a lysate of ca. 6 × 1010 PFU/ml. It was stable at pH 5 to 13 in normal saline at room temperature for at least 4 weeks and at −85°C for more than 2 years, while 1 × 109 out of 2 × 1012 PFU/ml retained infectivity after 36 months at 4°C. Stau2 could lyse 80% of the S. aureus isolates (164/205) obtained from hospitals in Taiwan, with complete lysis of most of the isolates tested within 3 h; however, it was an S. aureus-specific phage because no lytic infection could be found in the coagulase-negative staphylococci tested. Its host range among S. aureus isolates was wider than that of polyvalent phage K (47%), which can also lyse many other staphylococcal species. Experiments with mice demonstrated that Stau2 could provide 100% protection from lethal infection when a multiplicity of infection of 10 was administered immediately after a challenge with S. aureus S23. Considering these results, Stau2 could be considered at least as a candidate for topical phage therapy or an additive in the food industry. PMID:21148689

  12. The ltp gene of temperate Streptococcus thermophilus phage TP-J34 confers superinfection exclusion to Streptococcus thermophilus and Lactococcus lactis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sun Xingmin; Goehler, Andre; Heller, Knut J.

    2006-06-20

    The ltp gene, located within the lysogeny module of temperate Streptococcus thermophilus phage TP-J34, has been shown to be expressed in lysogenic strain S. thermophilus J34. It codes for a lipoprotein, as demonstrated by inhibition of cleavage of the signal sequence by globomycin. Exposure of Ltp on the surface of Lactococcus lactis protoplasts bearing a plasmid-encoded copy of ltp has been demonstrated by immunogold labeling and electron microscopy. Expression of ltp in prophage- and plasmid-cured S. thermophilus J34-6f interfered with TP-J34 infection. While plating efficiency was reduced by a factor of about 40 and lysis of strain J34-6f in liquidmore » medium was delayed considerably, phage adsorption was not affected at all. Intracellular accumulation of phage DNA was shown to be inhibited by Ltp. This indicates interference of Ltp with infection at the stage of triggering DNA release and injection into the cell, indicating a role of Ltp in superinfection exclusion. Expression of ltp in L. lactis Bu2-60 showed that the same superinfection exclusion mechanism was strongly effective against phage P008, a member of the lactococcal 936 phage species: no plaque-formation was detectable with even 10{sup 9} phage per ml applied, and lysis in liquid medium did not occur. In Lactococcus also, Ltp apparently inhibited phage DNA release and/or injection. Ltp appears to be a member of a family of small, secreted proteins with a 42 amino acids repeat structure encoded by genes of Gram-positive bacteria. Some of these homologous genes are part of the genomes of prophages.« less

  13. Characterization of Bacillus phage-K2 isolated from chungkookjang, a fermented soybean foodstuff.

    PubMed

    Kim, Eun Ju; Hong, Jeong Won; Yun, Na-Rae; Lee, Young Nam

    2011-01-01

    An investigation of a virulent Bacillus phage-K2 (named Bp-K2) isolated from chungkookjang (a fermented soybean foodstuff) was made. Bp-K2 differed in infectivity against a number of Bacillus subtilis strains including starter strains of chungkookjang and natto, being more infectious to Bacillus strains isolated from the chungkookjang, but much less active against a natto strain. Bp-K2 is a small DNA phage whose genome size is about 21 kb. Bp-K2 is a tailed bacteriophage with an isometric icosahedral head (50 nm long on the lateral side, 80 nm wide), a long contractile sheath (85-90 nm × 28 nm), a thin tail fiber (80-85 nm long, 10 nm wide), and a basal plate (29 nm long, 47 nm wide) with a number of spikes, but no collar. The details of the structures of Bp-K2 differ from natto phage ϕBN100 as well as other known Bacillus phages such as SPO1-like or ϕ 29-like viruses. These data suggest that Bp-K2 would be a new member of the Myoviridae family of Bacillus bacteriophages.

  14. The scope of phage display for membrane proteins.

    PubMed

    Vithayathil, Rosemarie; Hooy, Richard M; Cocco, Melanie J; Weiss, Gregory A

    2011-12-09

    Numerous examples of phage display applied to soluble proteins demonstrate the power of the technique for protein engineering, affinity reagent discovery and structure-function studies. Recent reports have expanded phage display to include membrane proteins (MPs). The scope and limitations of MP display remain undefined. Therefore, we report data from the phage display of representative types of membrane-associated proteins including plasma, nuclear, peripheral, single and multipass. The peripheral MP neuromodulin displays robustly with packaging by conventional M13-KO7 helper phage. The monotopic MP Nogo-66 can also display on the phage surface, if packaged by the modified M13-KO7(+) helper phage. The modified phage coat of KO7(+) can better mimic the zwitterionic character of the plasma membrane. Four examples of putatively α-helical, integral MPs failed to express as fusions to an anchoring phage coat protein and therefore did not display on the phage surface. However, the β-barrel MPs ShuA (Shigella heme uptake A) and MOMP (major outer membrane protein), which pass through the membrane 22 and 16 times, respectively, can display surprisingly well on the surfaces of both conventional and KO7(+) phages. The results provide a guide for protein engineering and large-scale mutagenesis enabled by the phage display of MPs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Identification of chondrocyte-binding peptides by phage display.

    PubMed

    Cheung, Crystal S F; Lui, Julian C; Baron, Jeffrey

    2013-07-01

    As an initial step toward targeting cartilage tissue for potential therapeutic applications, we sought cartilage-binding peptides using phage display, a powerful technology for selection of peptides that bind to molecules of interest. A library of phage displaying random 12-amino acid peptides was iteratively incubated with cultured chondrocytes to select phage that bind cartilage. The resulting phage clones demonstrated increased affinity to chondrocytes by ELISA, when compared to a wild-type, insertless phage. Furthermore, the selected phage showed little preferential binding to other cell types, including primary skin fibroblast, myocyte and hepatocyte cultures, suggesting a tissue-specific interaction. Immunohistochemical staining revealed that the selected phage bound chondrocytes themselves and the surrounding extracellular matrix. FITC-tagged peptides were synthesized based on the sequence of cartilage-binding phage clones. These peptides, but not a random peptide, bound cultured chondrocytes, and extracelluar matrix. In conclusion, using phage display, we identified peptide sequences that specifically target chondrocytes. We anticipate that such peptides may be coupled to therapeutic molecules to provide targeted treatment for cartilage disorders. Copyright © 2013 Orthopaedic Research Society.

  16. The triviality of abortion in Greece.

    PubMed

    Naziri, D

    1991-09-01

    In Greece modern contraceptive methods are used only in a very limited manner and abortion is the primary form of birth control. There are several social and psychological issues that are considered to be responsible. A 1985 study done for the Family Planning Center of Thessaloniki found that the ratio of live births is 1.3 and the ratio of abortion is 1.8/woman. 88% of women in the study had had an abortion while practicing coitus interruptus. 90% of the women never bought condoms. In a 1989 study only 6% of women had a positive attitude about condoms. Abortion is used as the primary method of birth control regardless of a woman's socioeconomic status. Further it was found that abortion did not correlate with other modern attitudes or the emancipation of women. The decision to abort was related to difficulties and constraints inherent in bring up a child. However positive attitudes toward contraception were related to educational and occupational levels. To complicate matters the information concerning contraceptives was problematic and related to the women's own lack of initiative to find out, and a lack of correct information offered from gynecologists. A 1990 study on knowledge, attitudes, beliefs and practices in relation to HIV infection indicated that the most favored method of contraception was condoms, but 60.8% of the men reported use versus 33.7% of the women. However these figures are not very representative because the survey was given in the context of HIV prevention and no attempt was made to distinguish between regular and irregular use patterns. Abortions is not a moral issue in Greece. It was legalized in 1986 only because it came to the attention of the government that the previous prohibition was being completely ignored. Abortion is strongly affected by social and psychological factors that are complex and result from cultural view points about fertility, maternal value, and life itself that are unique to the Greek culture.

  17. Mental health consequences of abortion and refused abortion.

    PubMed

    Watter, W W

    1980-02-01

    There is no scientific evidence to support the hypothesis put forth by Dr. Philip Ney in a recent article published in the Canadian Journal of Psychiatry that induced abortion is associated with an increase in child abuse. There are, however, numerous studies which support the contention that mandatory motherhood adversely affects the mental health of both the mother and the offspring. Studies conducted in Sweden, Scotland, and Czechoslovakia revealed that women who were refused abortions frequently experienced serious psychosocial difficulties for long periods of time following abortion refusal. Case controlled follow-up studies, conducted in Sweden and Czechoslovakia, of offspring born to women who were refused abortions demonstrated that a higher proportion of the unwanted children required psychiatric services, engaged in criminal behavior, and did less well in school than the controlled children. These studies have implications for the current Canadian law which permits a woman to obtain an abortion if pregnancy continuation will endanger her health. In view of the above statistical evidence, and the fact that mortality and morbidity are known to be lower for abortion than for childbirth, any person who denies a woman the right to have an abortion is increasing the risk that the health of the woman will be endangered. By law, therefore, all abortion requests should be honored.

  18. Detection of hepatitis B virus core antigen by phage display mediated TaqMan real-time immuno-PCR.

    PubMed

    Monjezi, Razieh; Tan, Sheau Wei; Tey, Beng Ti; Sieo, Chin Chin; Tan, Wen Siang

    2013-01-01

    The core antigen (HBcAg) of hepatitis B virus (HBV) is one of the markers for the identification of the viral infection. The main purpose of this study was to develop a TaqMan real-time detection assay based on the concept of phage display mediated immuno-PCR (PD-IPCR) for the detection of HBcAg. PD-IPCR combines the advantages of immuno-PCR (IPCR) and phage display technology. IPCR integrates the versatility of enzyme-linked immunosorbent assay (ELISA) with the sensitivity and signal generation power of PCR. Whereas, phage display technology exploits the physical association between the displayed peptide and the encoding DNA within the same phage particle. In this study, a constrained peptide displayed on the surface of an M13 recombinant bacteriophage that interacts tightly with HBcAg was applied as a diagnostic reagent in IPCR. The phage displayed peptide and its encoding DNA can be used to replace monoclonal antibody (mAb) and chemically bound DNA, respectively. This method is able to detect as low as 10ng of HBcAg with 10(8)pfu/ml of the recombinant phage which is about 10,000 times more sensitive than the phage-ELISA. The PD-IPCR provides an alternative means for the detection of HBcAg in human serum samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Genome Sequences of 12 Cluster AN Arthrobacter Phages

    PubMed Central

    Lee-Soety, Julia Y.; Bhatt, Shantanu; Adair, Tamarah L.; Bonilla, J. Alfred; Klyczek, Karen K.; Harrison, Melinda; Garlena, Rebecca A.; Bowman, Charles A.; Russell, Daniel A.; Jacobs-Sera, Deborah

    2017-01-01

    ABSTRACT Twelve siphoviral phages isolated using Arthrobacter sp. strain ATCC 21022 were sequenced. The phages all have relatively small genomes, ranging from 15,319 to 15,556 bp. All 12 phages are closely related to previously described cluster AN Arthrobacter phages. PMID:29122859

  20. [Screening serum response special antibodies of U251 cell line from surface display phage antibody library].

    PubMed

    Yu, Min; Tan, De-Yong; Qian, Wei; Lai, Jian-Hua; Sun, Gui-Lin

    2004-05-01

    U251 cell is a sensitive cell line to serum, which stops at G0 phase of cell cycle in no-serum medium, and recovers growth when the serum is added into no-serum medium. The cell can express corresponding proteins in different phase of cell cycle. Therefore it is very signification for the study of cell cycle regulation mechanism that explores these proteins. In this paper, the mouse antibody phage display library was added into the bottle in which the serum starvation U251 cells had been cultured, and the special antibody phages were absorbed. Then the absorbed antibody phages were amplified by adding E. coli TG1 and helper phage M13K07. Amplified antibody phages were added into bottle in which the serum cultured cell after serum starvation (follow named as serum recovered cells) were incubated, so that the cell absorbed the no-special antibody phages for the serum starvation cell and the special antibody phages were in supernatant. The remaining no-special antibody phages in the supernatant were discarded by repeating above program 3-4 times. The pure special antibody phages were gotten, and amplified by adding the host cell E. coli TG1 and helper phage M13K07. Then the host bacterium infected special antibody phage was spread on the plate medium with ampicillin, and the monoclonal antibody phages were gotten. Using same as above program, the monoclonal antibody phages absorbed specially for serum recovered U251 cells were obtained when the serum recovered cells instead of serum starvation cells and serum starvation cells instead of serum recovered cells. In this study, ninety-six positive monoclonal antibody phages that absorbed specially the serum starvation cells and eighty-two positive monoclonal antibody phages that absorbed specially the serum recovered cells were obtained. By using cell immunochemistry assay, two special signification antibodies were obtained. one (No.11) was the strong response in serum starvation cells, the other (No.2) was the strong

  1. Phage display: concept, innovations, applications and future.

    PubMed

    Pande, Jyoti; Szewczyk, Magdalena M; Grover, Ashok K

    2010-01-01

    Phage display is the technology that allows expression of exogenous (poly)peptides on the surface of phage particles. The concept is simple in principle: a library of phage particles expressing a wide diversity of peptides is used to select those that bind the desired target. The filamentous phage M13 is the most commonly used vector to create random peptide display libraries. Several methods including recombinant techniques have been developed to increase the diversity of the library. On the other extreme, libraries with various biases can be created for specific purposes. For instance, when the sequence of the peptide that binds the target is known, its affinity and selectivity can be increased by screening libraries created with limited mutagenesis of the peptide. Phage libraries are screened for binding to synthetic or native targets. The initial screening of library by basic biopanning has been extended to column chromatography including negative screening and competition between selected phage clones to identify high affinity ligands with greater target specificity. The rapid isolation of specific ligands by phage display is advantageous in many applications including selection of inhibitors for the active and allosteric sites of the enzymes, receptor agonists and antagonists, and G-protein binding modulatory peptides. Phage display has been used in epitope mapping and analysis of protein-protein interactions. The specific ligands isolated from phage libraries can be used in therapeutic target validation, drug design and vaccine development. Phage display can also be used in conjunction with other methods. The past innovations and those to come promise a bright future for this field. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. Expression of a Novel P22 ORFan Gene Reveals the Phage Carrier State in Salmonella Typhimurium

    PubMed Central

    Makumi, Angella; Ceyssens, Pieter-Jan; Lavigne, Rob; Van Houdt, Rob; Taddei, François

    2013-01-01

    We discovered a novel interaction between phage P22 and its host Salmonella Typhimurium LT2 that is characterized by a phage mediated and targeted derepression of the host dgo operon. Upon further investigation, this interaction was found to be instigated by an ORFan gene (designated pid for phage P22 encoded instigator of dgo expression) located on a previously unannotated moron locus in the late region of the P22 genome, and encoding an 86 amino acid protein of 9.3 kDa. Surprisingly, the Pid/dgo interaction was not observed during strict lytic or lysogenic proliferation of P22, and expression of pid was instead found to arise in cells that upon infection stably maintained an unintegrated phage chromosome that segregated asymmetrically upon subsequent cell divisions. Interestingly, among the emerging siblings, the feature of pid expression remained tightly linked to the cell inheriting this phage carrier state and became quenched in the other. As such, this study is the first to reveal molecular and genetic markers authenticating pseudolysogenic development, thereby exposing a novel mechanism, timing, and populational distribution in the realm of phage–host interactions. PMID:23483857

  3. Husbands' attitudes towards abortion and Canadian abortion law.

    PubMed

    Osborn, R W; Silkey, B

    1980-01-01

    In a 1975 study of attitudes toward abortion among a stratified sample of 601 men residing in Toronto and married to women of reproductive age, non-Catholic men and men who had weak religious beliefs had significantly more permissive attitudes toward abortion than Catholic men and men who had strong religious beliefs. Each respondent received a scale score based on his acceptance of abortion under 7 different conditions. The 7 conditions were: 1) threat to maternal life; 2) pregnancy due to rape; 3) predicted birth of a mentally or physically handicapped child; 4) threat to maternal mental health; 5) unmarried mother; 6) marriage breakdown; and 7) inability to financially support the child. A high score indicated a permissive attitude toward abortion. High scores were associated with high income and educational levels, non-Catholic affiliation, weak religious beliefs, and being Canadian by birth. When religious factors were controlled, the effect of the other factors was markedly reduced. No association was observed between scale scores and the variables of age and expected family size. A majority of the men approved of abortion for 5 or more of the above listed situations. Men with high scores were more likely to use effective methods of contraception, to be married to women who had abortions, and to favor less restrictive abortion laws. Non-Catholic men and men with weaker religious beliefs were more likely to favor easing the abortion law than Catholic men and men who had strong religious beliefs. Those with higher income and educational levels within each religious group were also more likely to favor easing the law. Tables show: 1) the % distribution of respondents approving abortion by reason for the abortion; and 2) the results of the analyses using various measures of association.

  4. A Study of Incomplete Abortion Following Medical Method of Abortion (MMA).

    PubMed

    Pawde, Anuya A; Ambadkar, Arun; Chauhan, Anahita R

    2016-08-01

    Medical method of abortion (MMA) is a safe, efficient, and affordable method of abortion. However, incomplete abortion is a known side effect. To study incomplete abortion due to medication abortion and compare to spontaneous incomplete abortion and to study referral practices and prescriptions in cases of incomplete abortion following MMA. Prospective observational study of 100 women with first trimester incomplete abortion, divided into two groups (spontaneous or following MMA), was administered a questionnaire which included information regarding onset of bleeding, treatment received, use of medications for abortion, its prescription, and administration. Comparison of two groups was done using Fisher exact test (SPSS 21.0 software). Thirty percent of incomplete abortions were seen following MMA; possible reasons being self-administration or prescription by unregistered practitioners, lack of examination, incorrect dosage and drugs, and lack of follow-up. Complications such as collapse, blood requirement, and fever were significantly higher in these patients compared to spontaneous abortion group. The side effects of incomplete abortions following MMA can be avoided by the following standard guidelines. Self medication, over- the-counter use, and prescription by unregistered doctors should be discouraged and reported, and need of follow-up should be emphasized.

  5. Genome Sequences of Ilzat and Eleri, Two Phages Isolated Using Microbacterium foliorum NRRL B-24224

    PubMed Central

    Ali, Ilzat; Jones, Acacia Eleri; Mohamed, Aleem

    2018-01-01

    ABSTRACT Bacteriophages Ilzat and Eleri are newly isolated Siphoviridae infecting Microbacterium foliorum NRRL B-24224. The phage genomes are similar in length, G+C content, and architecture and share 62.9% nucleotide sequence identity. PMID:29650566

  6. Ionic switch controls the DNA state in phage λ

    PubMed Central

    Li, Dong; Liu, Ting; Zuo, Xiaobing; Li, Tao; Qiu, Xiangyun; Evilevitch, Alex

    2015-01-01

    We have recently found that DNA packaged in phage λ undergoes a disordering transition triggered by temperature, which results in increased genome mobility. This solid-to-fluid like DNA transition markedly increases the number of infectious λ particles facilitating infection. However, the structural transition strongly depends on temperature and ionic conditions in the surrounding medium. Using titration microcalorimetry combined with solution X-ray scattering, we mapped both energetic and structural changes associated with transition of the encapsidated λ-DNA. Packaged DNA needs to reach a critical stress level in order for transition to occur. We varied the stress on DNA in the capsid by changing the temperature, packaged DNA length and ionic conditions. We found striking evidence that the intracapsid DNA transition is ‘switched on’ at the ionic conditions mimicking those in vivo and also at the physiologic temperature of infection at 37°C. This ion regulated on-off switch of packaged DNA mobility in turn affects viral replication. These results suggest a remarkable adaptation of phage λ to the environment of its host bacteria in the human gut. The metastable DNA state in the capsid provides a new paradigm for the physical evolution of viruses. PMID:26092697

  7. Ionic switch controls the DNA state in phage λ

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Dong; Liu, Ting; Zuo, Xiaobing

    We have recently found that DNA packaged in phage λ undergoes a disordering transition triggered by temperature, which results in increased genome mobility. This solid-to-fluid like DNA transition markedly increases the number of infectious λ particles facilitating infection. However, the structural transition strongly depends on temperature and ionic conditions in the surrounding medium. Using titration microcalorimetry combined with solution X-ray scattering, we mapped both energetic and structural changes associated with transition of the encapsidated λ-DNA. Packaged DNA needs to reach a critical stress level in order for transition to occur. We varied the stress on DNA in the capsid bymore » changing the temperature, packaged DNA length and ionic conditions. We found striking evidence that the intracapsid DNA transition is ‘switched on’ at the ionic conditions mimicking those in vivo and also at the physiologic temperature of infection at 37°C. This ion regulated on-off switch of packaged DNA mobility in turn affects viral replication. The results suggest a remarkable adaptation of phage λ to the environment of its host bacteria in the human gut. The metastable DNA state in the capsid provides a new paradigm for the physical evolution of viruses.« less

  8. Ionic switch controls the DNA state in phage λ

    DOE PAGES

    Li, Dong; Liu, Ting; Zuo, Xiaobing; ...

    2015-06-19

    We have recently found that DNA packaged in phage λ undergoes a disordering transition triggered by temperature, which results in increased genome mobility. This solid-to-fluid like DNA transition markedly increases the number of infectious λ particles facilitating infection. However, the structural transition strongly depends on temperature and ionic conditions in the surrounding medium. Using titration microcalorimetry combined with solution X-ray scattering, we mapped both energetic and structural changes associated with transition of the encapsidated λ-DNA. Packaged DNA needs to reach a critical stress level in order for transition to occur. We varied the stress on DNA in the capsid bymore » changing the temperature, packaged DNA length and ionic conditions. We found striking evidence that the intracapsid DNA transition is ‘switched on’ at the ionic conditions mimicking those in vivo and also at the physiologic temperature of infection at 37°C. This ion regulated on-off switch of packaged DNA mobility in turn affects viral replication. The results suggest a remarkable adaptation of phage λ to the environment of its host bacteria in the human gut. The metastable DNA state in the capsid provides a new paradigm for the physical evolution of viruses.« less

  9. Phage Life Cycles Behind Bacterial Biodiversity.

    PubMed

    Olszak, Tomasz; Latka, Agnieszka; Roszniowski, Bartosz; Valvano, Miguel A; Drulis-Kawa, Zuzanna

    2017-11-24

    Bacteriophages (phages or bacterial viruses) are the most abundant biological entities in our planet; their influence reaches far beyond the microorganisms they parasitize. Phages are present in every environment and shape up every bacterial population in both active and passive ways. They participate in the circulation of organic matter and drive the evolution of microorganisms by horizontal gene transfer at unprecedented scales. The mass flow of genetic information in the microbial world influences the biosphere and poses challenges for science and medicine. The genetic flow, however, depends on the fate of the viral DNA injected into the bacterial cell. The archetypal notion of phages only engaging in predatorprey relationships is slowly fading. Because of their varied development cycles, environmental conditions, and the diversity of microorganisms they parasitize, phages form a dense and highly complex web of dependencies, which has important consequences for life on Earth. The sophisticated phage-bacteria interplay includes both aggressive action (bacterial lysis) and "diplomatic negotiations" (prophage domestication). Here, we review the most important mechanisms of interactions between phages and bacteria and their evolutionary consequences influencing their biodiversity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. Membrane fusion during phage lysis.

    PubMed

    Rajaure, Manoj; Berry, Joel; Kongari, Rohit; Cahill, Jesse; Young, Ry

    2015-04-28

    In general, phages cause lysis of the bacterial host to effect release of the progeny virions. Until recently, it was thought that degradation of the peptidoglycan (PG) was necessary and sufficient for osmotic bursting of the cell. Recently, we have shown that in Gram-negative hosts, phage lysis also requires the disruption of the outer membrane (OM). This is accomplished by spanins, which are phage-encoded proteins that connect the cytoplasmic membrane (inner membrane, IM) and the OM. The mechanism by which the spanins destroy the OM is unknown. Here we show that the spanins of the paradigm coliphage lambda mediate efficient membrane fusion. This supports the notion that the last step of lysis is the fusion of the IM and OM. Moreover, data are provided indicating that spanin-mediated fusion is regulated by the meshwork of the PG, thus coupling fusion to murein degradation by the phage endolysin. Because endolysin function requires the formation of μm-scale holes by the phage holin, the lysis pathway is seen to require dramatic dynamics on the part of the OM and IM, as well as destruction of the PG.

  11. Gene Expression Patterns during Light and Dark Infection of Prochlorococcus by Cyanophage

    PubMed Central

    Chisholm, Sallie W.

    2016-01-01

    Cyanophage infecting the marine cyanobacteria Prochlorococcus and Synechococcus require light and host photosystem activity for optimal reproduction. Many cyanophages encode multiple photosynthetic electron transport (PET) proteins, which are presumed to maintain electron flow and produce ATP and NADPH for nucleotide biosynthesis and phage genome replication. However, evidence suggests phage augment NADPH production via the pentose phosphate pathway (PPP), thus calling into question the need for NADPH production by PET. Genes implicated in cyclic PET have since been identified in cyanophage genomes. It remains an open question which mode of PET, cyclic or linear, predominates in infected cyanobacteria, and thus whether the balance is towards producing ATP or NADPH. We sequenced transcriptomes of a cyanophage (P-HM2) and its host (Prochlorococcus MED4) throughout infection in the light or in the dark, and analyzed these data in the context of phage replication and metabolite measurements. Infection was robust in the light, but phage were not produced in the dark. Host gene transcripts encoding high-light inducible proteins and two terminal oxidases (plastoquinol terminal oxidase and cytochrome c oxidase)—implicated in protecting the photosynthetic membrane from light stress—were the most enriched in light but not dark infection. Among the most diminished transcripts in both light and dark infection was ferredoxin–NADP+ reductase (FNR), which uses the electron acceptor NADP+ to generate NADPH in linear photosynthesis. The phage gene for CP12, which putatively inhibits the Calvin cycle enzyme that receives NADPH from FNR, was highly expressed in light infection. Therefore, both PET production of NADPH and its consumption by carbon fixation are putatively repressed during phage infection in light. Transcriptomic evidence is thus consistent with cyclic photophosphorylation using oxygen as the terminal electron acceptor as the dominant mode of PET under infection

  12. An update in recurrent spontaneous abortion.

    PubMed

    Pandey, Manoj Kumar; Rani, Reena; Agrawal, Suraksha

    2005-07-01

    Recurrent spontaneous abortion (RSA) is defined as three or more consecutive pregnancy losses prior to the 20th week of gestation. The etiology of recurrent spontaneous abortion is often unclear and may be multifactorial, with much controversy regarding diagnosis and treatment. Reasonably accepted etiologic causes include, genetics, anatomical, endocrine, placental anomalies, hormonal problems, infection, smoking and alcohol consumption, exposure to environmental factors, psychological trauma and stressful life event, certain coagulation and immunoregulatory protein defects. Detection of an abnormality in any of these areas may result into specific therapeutic measures, with varying degrees of success. However, the majority of cases of RSA remains unexplained and is found to be associated with certain autoimmune (APA, ANA, ACA, ATA, AECA) and alloimmune (APCA, Ab2, MLR-Bf) antibodies that may play major role in the immunologic failure of pregnancy and may lead to abortion. Alteration in the expression of HLA-G molecules, T-helper-1 (Th-1) pattern of cytokines and natural killer (NK) cells activity may also induce abortion. Various forms of treatment like antithrombotic therapies such as aspirin and heparin, intravenous immunoglobulin (IVIg) therapy, immunotherapy with paternal lymphocytes and vitamin D3 therapy are effective mode of treatment for unexplained cause of fetal loss in women with RSA.

  13. Phage-Bacterial Dynamics with Spatial Structure: Self Organization around Phage Sinks Can Promote Increased Cell Densities

    PubMed Central

    Bull, James J.; Christensen, Kelly A.; Scott, Carly; Crandall, Cameron J.; Krone, Stephen M.

    2018-01-01

    Bacteria growing on surfaces appear to be profoundly more resistant to control by lytic bacteriophages than do the same cells grown in liquid. Here, we use simulation models to investigate whether spatial structure per se can account for this increased cell density in the presence of phages. A measure is derived for comparing cell densities between growth in spatially structured environments versus well mixed environments (known as mass action). Maintenance of sensitive cells requires some form of phage death; we invoke death mechanisms that are spatially fixed, as if produced by cells. Spatially structured phage death provides cells with a means of protection that can boost cell densities an order of magnitude above that attained under mass action, although the effect is sometimes in the opposite direction. Phage and bacteria self organize into separate refuges, and spatial structure operates so that the phage progeny from a single burst do not have independent fates (as they do with mass action). Phage incur a high loss when invading protected areas that have high cell densities, resulting in greater protection for the cells. By the same metric, mass action dynamics either show no sustained bacterial elevation or oscillate between states of low and high cell densities and an elevated average. The elevated cell densities observed in models with spatial structure do not approach the empirically observed increased density of cells in structured environments with phages (which can be many orders of magnitude), so the empirical phenomenon likely requires additional mechanisms than those analyzed here. PMID:29382134

  14. Physiological Properties and Genome Structure of the Hyperthermophilic Filamentous Phage φOH3 Which Infects Thermus thermophilus HB8.

    PubMed

    Nagayoshi, Yuko; Kumagae, Kenta; Mori, Kazuki; Tashiro, Kosuke; Nakamura, Ayano; Fujino, Yasuhiro; Hiromasa, Yasuaki; Iwamoto, Takeo; Kuhara, Satoru; Ohshima, Toshihisa; Doi, Katsumi

    2016-01-01

    A filamentous bacteriophage, φOH3, was isolated from hot spring sediment in Obama hot spring in Japan with the hyperthermophilic bacterium Thermus thermophilus HB8 as its host. Phage φOH3, which was classified into the Inoviridae family, consists of a flexible filamentous particle 830 nm long and 8 nm wide. φOH3 was stable at temperatures ranging from 70 to 90°C and at pHs ranging from 6 to 9. A one-step growth curve of the phage showed a 60-min latent period beginning immediately postinfection, followed by intracellular virus particle production during the subsequent 40 min. The released virion number of φOH3 was 109. During the latent period, both single stranded DNA (ssDNA) and the replicative form (RF) of phage DNA were multiplied from min 40 onward. During the release period, the copy numbers of both ssDNA and RF DNA increased sharply. The size of the φOH3 genome is 5688 bp, and eight putative open reading frames (ORFs) were annotated. These ORFs were encoded on the plus strand of RF DNA and showed no significant homology with any known phage genes, except ORF 5, which showed 60% identity with the gene VIII product of the Thermus filamentous phage PH75. All the ORFs were similar to predicted genes annotated in the Thermus aquaticus Y51MC23 and Meiothermus timidus DSM 17022 genomes at the amino acid sequence level. This is the first report of the whole genome structure and DNA multiplication of a filamentous T. thermophilus phage within its host cell.

  15. Abortion in Indonesia.

    PubMed

    Sedgh, Gilda; Ball, Haley

    2008-09-01

    Each year in Indonesia, millions of women become pregnant unintentionally, and many choose to end their pregnancies, despite the fact that abortion is generally illegal. Like their counterparts in many developing countries where abortion is stigmatized and highly restricted, Indonesian women often seek clandestine procedures performed by untrained providers, and resort to methods that include ingesting unsafe substances and undergoing harmful abortive massage. Though reliable evidence does not exist, researchers estimate that about two million induced abortions occur each year in the country and that deaths from unsafe abortion represent 14-16% of all maternal deaths in Southeast Asia. Preventing unsafe abortion is imperative if Indonesia is to achieve the fifth Millennium Development Goal of improving maternal health and reducing maternal mortality. Current Indonesian abortion law is based on a national health bill passed in 1992. Though the language on abortion was vague, it is generally accepted that the law allows abortion only if the woman provides confirmation from a doctor that her pregnancy is life-threatening, a letter of consent from her husband or a family member, a positive pregnancy test result and a statement guaranteeing that she will practice contraception afterwards. This report presents what is currently known about abortion in Indonesia. The findings are derived primarily from small-scale, urban, clinic-based studies of women's experiences with abortion. Some studies included women in rural areas and those who sought abortions outside of clinics, but none were nationally representative. Although these studies do not give a full picture of who is obtaining abortions in Indonesia or what their experiences are, the evidence suggests that abortion is a common occurrence in the country and that the conditions under which abortion takes place are often unsafe.

  16. Isolation and characterization of polyvalent bacteriophages infecting multi drug resistant Salmonella serovars isolated from broilers in Egypt.

    PubMed

    Mahmoud, Mayada; Askora, Ahmed; Barakat, Ahmed Barakat; Rabie, Omar El-Farouk; Hassan, Sayed Emam

    2018-02-02

    In this study, we isolated and characterized three phages named as Salmacey1, Salmacey2 and Salmacey3, infecting multi drug resistant Salmonella serovars isolated from broilers in Egypt. The most prevalent Salmonella serovars were S. typhimurium, S. enteritidis, and S. kentucky. All these Salmonella serovars were found to be resistant to more than two of the ten antimicrobial agents tested. Only S. kentucky was found to be resistant to seven antimicrobial agents. Examination of these phage particles by transmission electron microscopy (TEM), demonstrated that two phages (Salmacey1, Salmacey2) were found to belong to family Siphoviridae, and Salmacey3 was assigned to the family Myoviridae. The results of host range assay revealed that these bacteriophages were polyvalent and thus capable of infecting four strains of Salmonella serovars and Citrobacter freundii. Moreover, the two phages (Salmacey1, Salmacey2) had a lytic effect on Enterobacter cloacae and Salmacey3 was able to infect E. coli. All phages could not infect S. para Typhi, Staphylococus aureus and Bacillus cereus. One-step growth curves of bacteriophages revealed that siphovirus phages (Salmacey1, Salmacey2) have burst size (80 and 90pfu per infected cell with latent period 35min and 40min respectively), and for the myovirus Salmacey3 had a burst size 110pfu per infected cell with latent period 60min. Molecular analyses indicated that these phages contained double-stranded DNA genomes. The lytic activity of the phages against the most multidrug resistant serovars S. kentucky as host strain was evaluated. The result showed that these bacteriophages were able to completely stop the growth of S. kentucky in vitro. These results suggest that phages have a high potential for phage application to control Salmonella serovars isolated from broilers in Egypt. Copyright © 2017. Published by Elsevier B.V.

  17. A Novel Application of Synthetic Biology and Directed Evolution to Engineer Phage-based Antibiotics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wu, Meiye

    The emergence of multiple drug resistant bacteria poses threats to human health, agriculture and food safety. Annually over 100,000 deaths and up to $20 billion loss to the U.S. economy are attributed to multiple drug resistant bacteria. With only four new chemical antibiotics in the drug development pipeline, we are in dire need of new solutions to address the emerging threat of multiple drug resistance. We propose a paradigm-changing approach to address the multi-drug resistant bacteria problem by utilizing Synthetic Biology (SynBio) methodologies to create and evolve “designer” bacteriophages or phages – viruses that specifically infect bacteria – to infectmore » and kill newly emerging pathogenic bacterial strains WITHOUT the need for chemical antibiotics. A major advantage of using phage to combat pathogenic bacteria is that phages can co-evolve with their bacterial host, and Sandia can be the first in the world to establish an industrial scale Synthetic Biology pipeline for phage directed evolution for safe, targeted, customizable solution to bacterial drug resistance. Since there is no existing phage directed evolution effort within or outside of Sandia, this proposal is suitable as a high-risk LDRD effort to create the first pipeline for such an endeavor. The high potential reward nature of this proposal will be the immediate impact in decontamination and restoration of surfaces and infrastructure, with longer term impact in human or animal therapeutics. The synthetic biology and screening approaches will lead to fundamental knowledge of phage/bacteria co-evolution, making Sandia a world leader in directed evolution of bacteriophages.« less

  18. [Antibiotic prophylaxis with prulifloxacin in women undergoing induced abortion: a randomized controlled trial].

    PubMed

    Caruso, S; Di Mari, L; Cacciatore, A; Mammana, G; Agnello, C; Cianci, A

    2008-02-01

    To verify the efficacy of prulifloxacin in prevention of infective morbidity in women undergoing first trimester induced abortion. The aim of the study was to observe the incidence of infection during four weeks following abortion by monitoring the symptoms which require general practitioner prescription or hospitalization. Randomized controlled trial carried on by the Research Group for Sexology, Familiar Planning Service of the Department of Microbiological and Gynecological Science, University of Catania from September 2005 to March 2007. The study included 466 women, ranging in age from 14 to 44 years (mean age 26.7), who were randomized in three groups: group A (153 subjects) treated with 600 mg daily of prulifloxacin for 5 days after abortion; group B (155 subjects) treated with 600 mg daily of prulifloxacin for 3 days after abortion; group C (158 subjects) treated with 600 mg daily of prulifloxacin one day before and 2 days after abortion. Two hundred sixteen were nulliparous (47%), 96 were pluriparous (38.5%). Thirty-two nulliparous (15%) were under eighteen. Among pluriparous, 96 (38.5%) have had previous surgery delivery and 154 (61.5%) spontaneous delivery; moreover, 56 women have had previous surgical interruption during the first-trimester of pregnancy. Surgical abortion was practiced in a range of gestational age between 6th and 11th week of amenorrhea (average week 8.2). The percentage of pelvic inflammatory disease symptoms (pain, fever, leucoxantorrhea ) were about 10.5 in group A, 7.1 in group B and 2.5 in group C. Group C protocol was statistically more effective than group A protocol (P<0.05), but not than group B, even if prevalence of adverse events were less. Antibiotic prophylaxis before surgical abortion and shortening supplies after abortion is more effective than post abortion treatment alone.

  19. Target-specific copper hybrid T7 phage particles.

    PubMed

    Dasa, Siva Sai Krishna; Jin, Qiaoling; Chen, Chin-Tu; Chen, Liaohai

    2012-12-18

    Target-specific nanoparticles have attracted significant attention recently, and have greatly impacted life and physical sciences as new agents for imaging, diagnosis, and therapy, as well as building blocks for the assembly of novel complex materials. While most of these particles are synthesized by chemical conjugation of an affinity reagent to polymer or inorganic nanoparticles, we are promoting the use of phage particles as a carrier to host organic or inorganic functional components, as well as to display the affinity reagent on the phage surface, taking advantage of the fact that some phages host well-established vectors for protein expression. An affinity reagent can be structured in a desired geometry on the surface of phage particles, and more importantly, the number of the affinity reagent molecules per phage particle can be precisely controlled. We previously have reported the use of the T7 phage capsid as a template for synthesizing target-specific metal nanoparticles. In this study herein, we reported the synthesis of nanoparticles using an intact T7 phage as a scaffold from which to extend 415 copies of a peptide that contains a hexahistidine (6His) motif for capture of copper ions and staging the conversion of copper ions to copper metal, and a cyclic Arginine-Glycine-Aspartic Acid (RGD4C) motif for targeting integrin and cancer cells. We demonstrated that the recombinant phage could load copper ions under low bulk copper concentrations without interfering with its target specificity. Further reduction of copper ions to copper metal rendered a very stable copper hybrid T7 phage, which prevents the detachment of copper from phage particles and maintains the phage structural integrity even under harsh conditions. Cancer cells (MCF-7) can selectively uptake copper hybrid T7 phage particles through ligand-mediated transmembrane transportation, whereas normal control cells (MCF-12F) uptake 1000-fold less. We further demonstrated that copper hybrid T7

  20. Abortive Intestinal Infection With an Escherichia coli-Shigella flexneri Hybrid Strain

    PubMed Central

    Formal, Samuel B.; LaBrec, E. H.; Kent, T. H.; Falkow, S.

    1965-01-01

    Formal, Samuel B., (Walter Reed Army Institute of Research, Washington, D.C.), E. H. LaBrec, T. H. Kent, and S. Falkow. Abortive intestinal infection with an Escherichia coli-Shigella flexneri hybrid strain. J. Bacteriol. 89:1374–1382. 1965.—The mechanism of the apparent loss of virulence of an Escherichia coli-Shigella flexneri hybrid strain was studied. The parent Shigella strain caused a fatal enteric infection when fed to starved guinea pigs, and signs of dysentery followed its oral administration to monkeys. The hybrid strain failed to produce any apparent symptoms when fed to either of these species. The parent strain was shown to invade the intestinal mucosa of starved guinea pigs. This caused a severe inflammatory reaction in the lamina propria, which progressed to ulceration of the intestinal epithelium and resulted in death of the animal. The hybrid strain also invaded the intestinal mucosa and produced an inflammatory reaction. In this case, the inflammatory reaction subsided, the intestine returned to normal within 4 days after challenge, and the animal survived. Both fluorescent-antibody techniques and in vivo growth studies have shown that the hybrid strain can not maintain itself in the intestinal mucosa. Preliminary studies have indicated that a similar situation also exists in the monkey. It is concluded that the virulence of dysentery bacilli rests not only in the capacity to reach the lamina propria, but also in the ability to multiply in this region. Images PMID:14293011

  1. Abortion rights down under.

    PubMed

    Kirkby, M

    1994-08-01

    State and federal governments in Australia fear actively trying to ensure access to abortion. No federal abortion law in Australia exists. Abortion is a state matter. The federal government's health care system does reimburse women for abortion services, however. State laws prohibit unlawful abortions but they do not define what they mean by unlawful abortion. Victoria, New South Wales, and Queensland have had common law interpretations of their Crimes Acts, which allow greater access to abortion. Tasmania and Western Australia have not had common law interpretations. Thus, even though abortion is available, women and providers are not secure. Abortion reform in South Australia and the Northern Territory has made access to abortion more difficult. A woman must be a resident in South Australia for 2 months before she can obtain an abortion. Abortions are allowed only in a clinic or a hospital. Women in metropolitan Melbourne and Sydney have good access to abortion services, while those in the country or in an isolated part of NSW or Victoria may have an antiabortion physician serving their area. Women in Queensland, Tasmania, and Western Australia pay a lot for an abortion because they also have to pay for airfare to a large city. Only a gynecologist can perform abortions in the Northern Territory. Social workers often coerce Aboriginal women into an abortion. The few antiabortion physicians have a big impact on whether women receive abortion information or not. Research at Adelaide and Flinders Universities show that abortion-related trauma is linked to obtaining information and access to abortion services. Physicians are nervous about performing abortions because abortion is still in the Crimes Acts and Criminal Codes, making it difficult to recruit high quality and empathetic practitioners. Antiabortion groups are small and tend not to adopt extreme tactics. The Abortion Rights Network of Australia has recently been formed.

  2. Gene 1.7 of bacteriophage T7 confers sensitivity of phage growth to dideoxythymidine.

    PubMed

    Tran, Ngoc Q; Rezende, Lisa F; Qimron, Udi; Richardson, Charles C; Tabor, Stanley

    2008-07-08

    Bacteriophage T7 DNA polymerase efficiently incorporates dideoxynucleotides into DNA, resulting in chain termination. Dideoxythymidine (ddT) present in the medium at levels not toxic to Escherichia coli inhibits phage T7. We isolated 95 T7 phage mutants that were resistant to ddT. All contained a mutation in T7 gene 1.7, a nonessential gene of unknown function. When gene 1.7 was expressed from a plasmid, T7 phage resistant to ddT still arose; analysis of 36 of these mutants revealed that all had a single mutation in gene 5, which encodes T7 DNA polymerase. This mutation changes tyrosine-526 to phenylalanine, which is known to increase dramatically the ability of T7 DNA polymerase to discriminate against dideoxynucleotides. DNA synthesis in cells infected with wild-type T7 phage was inhibited by ddT, suggesting that it resulted in chain termination of DNA synthesis in the presence of gene 1.7 protein. Overexpression of gene 1.7 from a plasmid rendered E. coli cells sensitive to ddT, indicating that no other T7 proteins are required to confer sensitivity to ddT.

  3. Wide screening of phage-displayed libraries identifies immune targets in planta.

    PubMed

    Rioja, Cristina; Van Wees, Saskia C; Charlton, Keith A; Pieterse, Corné M J; Lorenzo, Oscar; García-Sánchez, Susana

    2013-01-01

    Microbe-Associated Molecular Patterns and virulence effectors are recognized by plants as a first step to mount a defence response against potential pathogens. This recognition involves a large family of extracellular membrane receptors and other immune proteins located in different sub-cellular compartments. We have used phage-display technology to express and select for Arabidopsis proteins able to bind bacterial pathogens. To rapidly identify microbe-bound phage, we developed a monitoring method based on microarrays. This combined strategy allowed for a genome-wide screening of plant proteins involved in pathogen perception. Two phage libraries for high-throughput selection were constructed from cDNA of plants infected with Pseudomonas aeruginosa PA14, or from combined samples of the virulent isolate DC3000 of Pseudomonas syringae pv. tomato and its avirulent variant avrRpt2. These three pathosystems represent different degrees in the specificity of plant-microbe interactions. Libraries cover up to 2 × 10(7) different plant transcripts that can be displayed as functional proteins on the surface of T7 bacteriophage. A number of these were selected in a bio-panning assay for binding to Pseudomonas cells. Among the selected clones we isolated the ethylene response factor ATERF-1, which was able to bind the three bacterial strains in competition assays. ATERF-1 was rapidly exported from the nucleus upon infiltration of either alive or heat-killed Pseudomonas. Moreover, aterf-1 mutants exhibited enhanced susceptibility to infection. These findings suggest that ATERF-1 contains a microbe-recognition domain with a role in plant defence. To identify other putative pathogen-binding proteins on a genome-wide scale, the copy number of selected-vs.-total clones was compared by hybridizing phage cDNAs with Arabidopsis microarrays. Microarray analysis revealed a set of 472 candidates with significant fold change. Within this set defence-related genes, including well

  4. In vitro high throughput phage display selection of ovarian cancer avid phage clones for near-infrared optical imaging.

    PubMed

    Soendergaard, Mette; Newton-Northup, Jessica R; Deutscher, Susan L

    2014-01-01

    Ovarian cancer is among the leading causes of cancer deaths in women, and is the most fatal gynecological malignancy. Poor outcomes of the disease are a direct result of inadequate detection and diagnostic methods, which may be overcome by the development of novel efficacious screening modalities. However, the advancement of such technologies is often time-consuming and costly. To overcome this hurdle, our laboratory has established a time and cost effective method of selecting and identifying ovarian carcinoma avid bacteriophage (phage) clones using high throughput phage display technology. These phage clones were selected from a filamentous phage fusion vector (fUSE5) 15-amino acid peptide library against human ovarian carcinoma (SKOV-3) cells, and identified by DNA sequencing. Two phage clones, pM6 and pM9, were shown to exhibit high binding affinity and specificity for SKOV-3 cells using micropanning, cell binding and fluorescent microscopy studies. To validate that the binding was mediated by the phage-displayed peptides, biotinylated peptides (M6 and M9) were synthesized and the specificity for ovarian carcinoma cells was analyzed. These results showed that M6 and M9 bound to SKOV-3 cells in a dose-response manner and exhibited EC50 values of 22.9 ± 2.0 μM and 12.2 ± 2.1μM (mean ± STD), respectively. Based on this, phage clones pM6 and pM9 were labeled with the near-infrared fluorophore AF680, and examined for their pharmacokinetic properties and tumor imaging abilities in vivo. Both phage successfully targeted and imaged SKOV-3 tumors in xenografted nude mice, demonstrating the ability of this method to quickly and cost effectively develop novel ovarian carcinoma avid phage.

  5. 1st German Phage Symposium—Conference Report

    PubMed Central

    Huber, Irene; Potapova, Katerina; Kuhn, Andreas; Schmidt, Herbert; Hinrichs, Jörg; Rohde, Christine; Beyer, Wolfgang

    2018-01-01

    In Germany, phage research and application can be traced back to the beginning of the 20th century. However, with the triumphal march of antibiotics around the world, the significance of bacteriophages faded in most countries, and respective research mainly focused on fundamental questions and niche applications. After a century, we pay tribute to the overuse of antibiotics that led to multidrug resistance and calls for new strategies to combat pathogenic microbes. Against this background, bacteriophages came into the spotlight of researchers and practitioners again resulting in a fast growing “phage community”. In October 2017, part of this community met at the 1st German Phage Symposium to share their knowledge and experiences. The participants discussed open questions and challenges related to phage therapy and the application of phages in general. This report summarizes the presentations given, highlights the main points of the round table discussion and concludes with an outlook for the different aspects of phage application. PMID:29596346

  6. Construction of a filamentous phage display peptide library.

    PubMed

    Fagerlund, Annette; Myrset, Astrid Hilde; Kulseth, Mari Ann

    2014-01-01

    The concept of phage display is based on insertion of random oligonucleotides at an appropriate location within a structural gene of a bacteriophage. The resulting phage will constitute a library of random peptides displayed on the surface of the bacteriophages, with the encoding genotype packaged within each phage particle. Using a phagemid/helper phage system, the random peptides are interspersed between wild-type coat proteins. Libraries of phage-expressed peptides may be used to search for novel peptide ligands to target proteins. The success of finding a peptide with a desired property in a given library is highly dependent on the diversity and quality of the library. The protocols in this chapter describe the construction of a high-diversity library of phagemid vector encoding fusions of the phage coat protein pVIII with random peptides, from which a phage library displaying random peptides can be prepared.

  7. Excision of thymine dimers in vitro by extracts of bacteriophage-infected Escherichia coli

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Friedberg, E.C.; Minton, K.; Pawl, G.

    1974-05-01

    Extracts of DNA polymerase I defective Escherichia coli infected with phage T4 contain an exonuclease activity that removes thymine dimers from uv- irradiated DNA previously nicked with T4 uv endonuclease. This activity is not expressed if cells are infected in the presence of chloramphenicol. The enzyme has a requirement for divalent cation and is not affected by caffeine, but excision is inhibited in the presence of proflavine. The enzyme is present in all phage T4 mutants thus far examined, including 25 uv-sensitive mutants isolated during the course of the experiments, all of which are defective in the v gene. Amore » similar activity can be detected in cells infected with phages T2, T3, and T6, but not in cells infected with phage T7. (auth)« less

  8. Isolation and characterization of T7-like lytic bacteriophages infecting multidrug resistant Pseudomonas aeruginosa isolated from Egypt.

    PubMed

    El Didamony, Gamal; Askora, Ahmed; Shehata, Aya A

    2015-06-01

    In this study, two lytic phages designated as ϕPSZ1 and ϕPSZ2 infecting multidrug resistant Pseudomonas aeruginosa were isolated from sewage samples collected in Zagazig, Egypt. Morphological analysis by transmission electron microscopy revealed that both phages belong to the podoviridae family and resembles typical T7-like phages. ϕPSZ1 has a head of about 60 ± 5 nm in diameter with a short tail of 19 ± 2 nm in length, while ϕPSZ2 has a head of about 57 ± 5 nm in diameter with a short tail of 14 ± 2 nm in length. Both phages were shown to be able to infect 13 different P. aeruginosa strains and has no effect on other tested bacteria. In spite of morphological similarity, these phages showed diverged genomic sequences revealed by restriction enzyme digestion analysis. One-step growth curves of bacteriophages revealed eclipse and latent periods of 12 min for ϕPSZ1 and 15 min for ϕPSZ2, respectively, with burst sizes of about 100 per infected cell. Phage treatment prevented the growth of P. aeruginosa for up to 18 h with multiplicity of infection ratios of 1. These results suggest that both phages have a high potential for phage application to control P. aeruginosa.

  9. Phage-induced lysis enhances biofilm formation in Shewanella oneidensis MR-1

    PubMed Central

    Gödeke, Julia; Paul, Kristina; Lassak, Jürgen; Thormann, Kai M

    2011-01-01

    Shewanella oneidensis MR-1 is capable of forming highly structured surface-attached communities. By DNase I treatment, we demonstrated that extracellular DNA (eDNA) serves as a structural component in all stages of biofilm formation under static and hydrodynamic conditions. We determined whether eDNA is released through cell lysis mediated by the three prophages LambdaSo, MuSo1 and MuSo2 that are harbored in the genome of S. oneidensis MR-1. Mutant analyses and infection studies revealed that all three prophages may individually lead to cell lysis. However, only LambdaSo and MuSo2 form infectious phage particles. Phage release and cell lysis already occur during early stages of static incubation. A mutant devoid of the prophages was significantly less prone to lysis in pure culture. In addition, the phage-less mutant was severely impaired in biofilm formation through all stages of development, and three-dimensional growth occurred independently of eDNA as a structural component. Thus, we suggest that in S. oneidensis MR-1 prophage-mediated lysis results in the release of crucial biofilm-promoting factors, in particular eDNA. PMID:20962878

  10. Provision of intrauterine contraception in association with first trimester induced abortion reduces the need of repeat abortion: first-year results of a randomized controlled trial.

    PubMed

    Pohjoranta, Elina; Mentula, Maarit; Gissler, Mika; Suhonen, Satu; Heikinheimo, Oskari

    2015-11-01

    Can the need of subsequent abortion be reduced by providing intrauterine contraception as a part of the abortion service? Provision of intrauterine devices (IUDs) in association with first trimester abortion more than halved the incidence of repeat abortion during the first year of follow-up. Following abortion, the incidence of subsequent abortion is high, up to 30-40%. In cohort studies, intrauterine contraception has reduced the need of repeat abortion by 60-70%. A randomized controlled trial. The main outcome measure was the incidence of subsequent induced abortions during the follow-up. Altogether 751 women seeking first trimester induced abortion were recruited and randomized into two groups. Randomization was accomplished by computer-assisted permuted-block randomization with random block sizes of four to six. The investigators did not participate in randomization, which was done before commencing the study. The participants were recruited between 18 October 2010 and 21 January 2013. The inclusion criteria were age ≥18 years, duration of pregnancy ≤12 weeks, accepting intrauterine contraception, residence in Helsinki and signing the informed consent form. Women with contraindications to intrauterine contraception, such as uterine anomaly, acute genital infection or pap-smear change requiring surgical treatment were ineligible to participate.This study was conducted in collaboration between the Department of Obstetrics and Gynaecology, University of Helsinki and Helsinki University Hospital, and Centralized family planning of the City of Helsinki.The intervention group (n = 375) was provided with intrauterine contraception (either the levonorgestrel-releasing intrauterine system or copper-releasing intrauterine device) immediately following surgical abortion (18.1%) or at a follow-up 2-4 weeks after medical abortion (81.9%). Women in the control group were prescribed oral contraceptives and advised to contact their primary healthcare unit for a follow

  11. Genomic Characterization of Sixteen Yersinia enterocolitica-Infecting Podoviruses of Pig Origin

    PubMed Central

    Salem, Mabruka

    2018-01-01

    Yersinia enterocolitica causes enteric infections in humans and animals. Human infections are often caused by contaminated pork meat. Y. enterocolitica colonizes pig tonsils and pigs secrete both the human pathogen and its specific bacteriophages into the stools. In this work, sixteen Y. enterocolitica—infecting lytic bacteriophages isolated from pig stools originating from several pig farms were characterized. All phages belong to the Podoviridae family and their genomes range between 38,391–40,451 bp in size. The overall genome organization of all the phages resembled that of T7-like phages, having 3–6 host RNA polymerase (RNAP)-specific promoters at the beginning of the genomes and 11–13 phage RNAP-specific promoters as well as 3–5 rho-independent terminators, scattered throughout the genomes. Using a ligation-based approach, the physical termini of the genomes containing direct terminal repeats of 190–224 bp were established. No genes associated with lysogeny nor any toxin, virulence factor or antibiotic resistance genes were present in the genomes. Even though the phages had been isolated from different pig farms the nucleotide sequences of their genomes were 90–97% identical suggesting that the phages were undergoing microevolution within and between the farms. Lipopolysaccharide was found to be the surface receptor of all but one of the phages. The phages are classified as new species within the T7virus genus of Autographivirinae subfamily. PMID:29614052

  12. Cytotoxic Tumor-Targeting Peptides From In Vivo Phage Display.

    PubMed

    Northup, Jessica R Newton; Deutscher, Susan L

    2016-01-01

    We previously utilized an in vivo peptide phage display selection technique, which included the use of detergent elution of phage from excised tumor, to obtain tumor-targeting phage with the ability to extravasate the vasculature and bind directly to prostate tumor tissue. It is hypothesized that this same in vivo phage selection technique can be used to functionally select for molecules that not only bind to cancer cells but also kill them. Here we analyzed two different in vivo phage display selected phage clones, G1 and H5, retrieved from PC-3 human prostate carcinoma xenografted tumors. First, cell de-attachment as an endpoint criterion for apoptosis and cell cycle was examined. After 2.5 hours incubation with G1 phage, PC-3 cell attachment was reduced by 23.8% and the percent of cell population in M phase reduced by 32.1%. In comparison, PC-3 cells incubated with H5 phage had a reduction of 25.0% cell attachment and 33.6% of cell population in M phase. These changes in combination with elevated caspase activation within cells in M phase, and no significant changes to G1/G0 or S phase cell populations suggest that the cytotoxic phages are targeting actively dividing PC-3 cells. Microscopic studies were also performed to further analyze the nature of cytotoxicity of these two phage clones. It was found that G1 phage induced and co- localized with tubulin based projections within apoptotic cells, while H5 phage did not. These phage may form the foundation for a new class of targeted prostate cancer therapeutic agents.

  13. Abortion legalized: challenges ahead.

    PubMed

    Singh, M; Jha, R

    2007-01-01

    To see whether advocacy for abortion law and comprehensive abortion care (CAC) sites after legalization of abortion in Nepal is adequate among educated people (above school leaving certificate). 150 participants were assigned randomly who agreed to be in the survey and were given structured questionnaires to find out their perception of abortion and CAC sites. Majority know abortion is legalized and majority have positive attitude about legalization of abortion, however majority are not aware of abortion service in CAC sites and none knew the cost of abortion service. Proper and adequate advocacy of the new abortion law and CAC service is essential.

  14. Peptides Derived from a Phage Display Library Inhibit Adhesion and Protect the Host against Infection by Paracoccidioides brasiliensis and Paracoccidioides lutzii

    PubMed Central

    de Oliveira, Haroldo C.; Michaloski, Jussara S.; da Silva, Julhiany F.; Scorzoni, Liliana; de Paula e Silva, Ana C. A.; Marcos, Caroline M.; Assato, Patrícia A.; Yamazaki, Daniella S.; Fusco-Almeida, Ana M.; Giordano, Ricardo J.; Mendes-Giannini, Maria J. S.

    2016-01-01

    Paracoccidioides brasiliensis and Paracoccidioides lutzii are dimorphic fungi and are the etiological agents of paracoccidioidomycosis (PCM). Adhesion is one of the most important steps in infections with Paracoccidioides and is responsible for the differences in the virulence of isolates of these fungi. Because of the importance of adhesion to the establishment of an infection, this study focused on the preliminary development of a new therapeutic strategy to inhibit adhesion by Paracoccidioides, thus inhibiting infection and preventing the disease. We used two phage display libraries to select peptides that strongly bind to the Paracoccidioides cell wall to inhibit adhesion to host cells and extracellular matrix (ECM) components (laminin, fibronectin, and type I and type IV collagen). This approach allowed us to identify four peptides that inhibited up to 64% of the adhesion of Paracoccidioides to pneumocytes in vitro and inhibited the adhesion to the ECM components by up to 57%. Encouraged by these results, we evaluated the ability of these peptides to protect Galleria mellonella from Paracoccidioides infection by treating G. mellonella larvae with the different peptides prior to infection with Paracoccidioides and observing larval survival. The results show that all of the peptides tested increased the survival of the larvae infected with P. brasiliensis by up to 64% and by up to 60% in those infected with P. lutzii. These data may open new horizons for therapeutic strategies to prevent PCM, and anti-adhesion therapy could be an important strategy. PMID:28066254

  15. Phage display screening without repetitious selection rounds.

    PubMed

    't Hoen, Peter A C; Jirka, Silvana M G; Ten Broeke, Bradley R; Schultes, Erik A; Aguilera, Begoña; Pang, Kar Him; Heemskerk, Hans; Aartsma-Rus, Annemieke; van Ommen, Gertjan J; den Dunnen, Johan T

    2012-02-15

    Phage display screenings are frequently employed to identify high-affinity peptides or antibodies. Although successful, phage display is a laborious technology and is notorious for identification of false positive hits. To accelerate and improve the selection process, we have employed Illumina next generation sequencing to deeply characterize the Ph.D.-7 M13 peptide phage display library before and after several rounds of biopanning on KS483 osteoblast cells. Sequencing of the naive library after one round of amplification in bacteria identifies propagation advantage as an important source of false positive hits. Most important, our data show that deep sequencing of the phage pool after a first round of biopanning is already sufficient to identify positive phages. Whereas traditional sequencing of a limited number of clones after one or two rounds of selection is uninformative, the required additional rounds of biopanning are associated with the risk of losing promising clones propagating slower than nonbinding phages. Confocal and live cell imaging confirms that our screen successfully selected a peptide with very high binding and uptake in osteoblasts. We conclude that next generation sequencing can significantly empower phage display screenings by accelerating the finding of specific binders and restraining the number of false positive hits. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. The politicization of abortion and the evolution of abortion counseling.

    PubMed

    Joffe, Carole

    2013-01-01

    The field of abortion counseling originated in the abortion rights movement of the 1970s. During its evolution to the present day, it has faced significant challenges, primarily arising from the increasing politicization and stigmatization of abortion since legalization. Abortion counseling has been affected not only by the imposition of antiabortion statutes, but also by the changing needs of patients who have come of age in a very different era than when this occupation was first developed. One major innovation--head and heart counseling--departs in significant ways from previous conventions of the field and illustrates the complex and changing political meanings of abortion and therefore the challenges to abortion providers in the years following Roe v Wade.

  17. Valyl-tRNA synthetase modification-dependent restriction of bacteriophage T4.

    PubMed Central

    Olson, N J; Marchin, G L

    1984-01-01

    A strain of Escherichia coli, CP 790302, severely restricts the growth of wild-type bacteriophage T4. In broth culture, most infections of single cells are abortive, although a few infected cells exhibit reduced burst sizes. In contrast, bacteriophage T4 mutants impaired in the ability to modify valyl-tRNA synthetase develop normally on this strain. Biochemical evidence indicates that the phage-modified valyl-tRNA synthetase in CP 790302 is different from that previously described. Although the enzyme is able to support normal protein synthesis, a disproportionate amount of phage structural protein (serum blocking power) fails to mature into particles of the appropriate density. The results with host strain CP 790302 are consistent with either a gratuitous inhibition of phage assembly by faulty modification or abrogation of an unknown role that valyl-tRNA synthetase might normally play in viral assembly. PMID:6374167

  18. Anti-legal attitude toward abortion among abortion patients in the United States.

    PubMed

    Thomas, Rachel G; Norris, Alison H; Gallo, Maria F

    2017-11-01

    To measure the prevalence of believing that abortion should be illegal in all or most cases among women obtaining an abortion in the United States and to identify correlates of holding this belief. Study population was drawn from the nationally-representative 2008 Abortion Patient Survey. The primary outcome was having an anti-legal abortion attitude, defined as agreeing that abortion should be illegal in all or most cases. We assessed potential correlates in bivariable and multivariable analyses using weights to account for the complex sampling. A total of 4769 abortion patients completed the survey module containing the question on abortion legality, of which 4492 (94.2%) had non-missing data for the outcome. Overall, 4.1% of patients (N=183) reported an anti-legal abortion attitude. Correlates of having anti-legal attitude included being married, at <200% federal poverty level, fundamentalist, contraception non-use, no abortion history, perceiving the pregnancy with ambivalence or as unintended, and using misoprostol or another product on their own to bring back their period or end the pregnancy. Abortion patients who do not believe abortion should be legal appear to differ substantially from women who are more supportive of legality. Findings raise important questions about this subset of patients, including whether possible discordance between patient beliefs and behavior could influence their use of medical abortion or other products. Some abortion patients do not agree with abortion legality, and this subset could experience a degree of cognitive dissonance, which could influence the method by which they seek to abort. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Phage inactivation of Staphylococcus aureus in fresh and hard-type cheeses.

    PubMed

    Bueno, Edita; García, Pilar; Martínez, Beatriz; Rodríguez, Ana

    2012-08-01

    Bacteriophages are regarded as natural antibacterial agents in food since they are able to specifically infect and lyse food-borne pathogenic bacteria without disturbing the indigenous microbiota. Two Staphylococcus aureus obligately lytic bacteriophages (vB_SauS-phi-IPLA35 and vB_SauS-phi-SauS-IPLA88), previously isolated from the dairy environment, were evaluated for their potential as biocontrol agents against this pathogenic microorganism in both fresh and hard-type cheeses. Pasteurized milk was contaminated with S. aureus Sa9 (about 10(6) CFU/mL) and a cocktail of the two lytic phages (about 10(6) PFU/mL) was also added. For control purposes, cheeses were manufactured without addition of phages. In both types of cheeses, the presence of phages resulted in a notorious decrease of S. aureus viable counts during curdling. In test fresh cheeses, a reduction of 3.83 log CFU/g of S. aureus occurred in 3h compared with control cheese, and viable counts were under the detection limits after 6h. The staphylococcal strain was undetected in both test and control cheeses at the end of the curdling process (24 h) and, of note, no re-growth occurred during cold storage. In hard cheeses, the presence of phages resulted in a continuous reduction of staphylococcal counts. In curd, viable counts of S. aureus were reduced by 4.64 log CFU/g compared with the control cheeses. At the end of ripening, 1.24 log CFU/g of the staphylococcal strain was still detected in test cheeses whereas 6.73log CFU/g was present in control cheeses. Starter strains were not affected by the presence of phages in the cheese making processes and cheeses maintained their expected physico-chemical properties. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Why Abortion is Illegal? Comparison of Legal and Illegal Abortion: A Critical Review.

    PubMed

    Huq, M E; Raihan, M J; Shirin, H; Chowdhury, S; Jahan, Y; Chowdhury, A S; Rahman, M M

    2017-10-01

    Abortion is the termination of pregnancy that occurs spontaneously or purposely. In the most developed world, abortion is legally allowed for women seeking safe termination of pregnancies. Particularly, when access to legal abortion is restricted, abortion is the resort to unsafe methods. The aim of this review is to necessitate safe abortion and to accentuate the consequences of illegal abortion in case of legal prohibition. We used Pubmed, MedLine and Scopus databases to review previous literatures of safe, unsafe, legal and illegal abortions. Research work and reports from organizations such as World Health Organization (WHO), World Bank (WB) and United Nations (UN) were included. Snowball sampling was used to obtain relevant journals. Abortion is conventional whether it is safe, unsafe, legal or illegal. The intention of the antiabortion policy was to reduce the number of abortions globally. However, instead of decreasing rates, evidences show significant increase in abortions. When abortion is legal, the preconditions to be ensured are availability, accessibility, affordability and acceptability for the safe abortion facilities. When abortion is illegal, risk reduction strategies are needed to decrease maternal morbidity and mortality. We can reduce abortion related morbidity and mortality, whether it is legal or illegal if we can ensure the appropriate access to health care, including abortion services, education on sexuality, access to contraceptives, post abortion care, and suitable interventions and liberalization of laws. The paper reviewed the Mexico City Policy and the US foreign aid strategies and highlighted the evidence based analysis for policy reform. The liberalized abortion law can save pregnant women from abortion related complications and death.

  1. A century of phage research: bacteriophages and the shaping of modern biology.

    PubMed

    Keen, Eric C

    2015-01-01

    2015 marks the centennial of the discovery of bacteriophages, viruses that infect bacteria. Phages have been central to some of biology's most meaningful advances over the past hundred years (shown here); they greatly influence the workings of the biosphere, and are poised to play expanded roles in biomedicine, biotechnology, and ecology. © 2015 WILEY Periodicals, Inc.

  2. Abortion

    MedlinePlus

    An abortion is a procedure to end a pregnancy. It uses medicine or surgery to remove the embryo or ... personal. If you are thinking of having an abortion, most health care providers advise counseling.

  3. Phages Make for Jolly Good Stories

    PubMed Central

    2018-01-01

    Phage therapy has an intriguing history. It was widely used from the 1920s until the 1940s. After this period, it was nearly completely forgotten in the Western world, while it continued to be used in the Soviet part of the globe. The study of the history of phage therapy provides valuable input into the present development of the field. Science journalists uncovered much of this history and played an important role in the communication of phage therapy after the fall of the Soviet Union, when it came to the attention of Western researchers and doctors. This interest was fueled by the antibiotic resistance crisis. At this time, communication about phage therapy had a wide potential audience, that encompassed medical experts and researchers, as well as the public, because knowledge about this forgotten therapy was very limited. In such a situation, good communication had and still has the potential to catalyze important discussions among different groups; whereas, bad communication could have considerably hindered and still can hinder the possible renaissance of phage therapy. PMID:29677137

  4. Isolation, characterization and comparative genomics of bacteriophage SfIV: a novel serotype converting phage from Shigella flexneri

    PubMed Central

    2013-01-01

    evolution of these phages, and will also facilitate studies on development of new phage vectors and therapeutic agents to control infections caused by S. flexneri. PMID:24090466

  5. Abortion denied--outcome of mothers and babies.

    PubMed

    Del Campo, C

    1984-02-15

    A consistent argument favoring therapeutic abortions has been that mothers who are denied abortions will seek "illegal" help elsewhere, often in less than optimal conditions. Yet, a review of published reports on women who had been denied abortion and were followed up shows that 70.67% of the 6298 women completed their pregnancies and only 13.2% had an abortion elsewhere. Several studies have shown that the incidence of Complications of pregnancy is no greater in mothers denied abortion than in paired controls. The results of a prospective study by Laukaran and Van Den Berg showed a higher incidence of maternal accidental injury, a borderline increase of maternal accidental injury, a borderline increase in the prevalence of congenital anomalies, and a higher incidence of infection and hemorrhage during the puerperium in women who had been denied abortion. They concluded that maternal attitude and psychosocial stress had little effect on the progress of the pregnancy and labor. Published reports on the psychological effects on the children of women who had been denied abortion are few, mainly because longterm follow-up is required. In 1966 Forssman and Thuwe described the results of their study of 120 children whose mothers had been denied abortion. The children had been followed up until their 21st birthdays. The controls had been carefully paired. The proportion of children who had been placed in foster and children's homes was significantly higher among the "unwanted" children than among the controls (50% versus 18%). There was no statistically significant difference in the rates of drunken misconduct, crime, or "educational mental subnormality" between the 2 groups, but the incidence rates of delinquency and psychiatric consultation were 10% and 13% higher respectively among the unwanted children than among the controls. There have been virtually no objective studies on the psychologic and social well-being of women who have been denied abortion. The literature

  6. Abortion: a history.

    PubMed

    Hovey, G

    1985-01-01

    This review of abortion history considers sacred and secular practice and traces abortion in the US, the legacy of the 19th century, and the change that occurred in the 20th century. Abortion has been practiced since ancient times, but its legality and availability have been threatened continuously by forces that would denigrate women's fundamental rights. Currently, while efforts to decrease the need for abortion through contraception and education continue, access to abortion remains crucial for the well-being of millions of women. That access will never be secure until profound changes occur in the whole society. Laws that prohibit absolutely the practice of abortion are a relatively recent development. In the early Roman Catholic church, abortion was permitted for male fetuses in the first 40 days of pregnancy and for female fetuses in the first 80-90 days. Not until 1588 did Pope Sixtus V declare all abortion murder, with excommunication as the punishment. Only 3 years later a new pope found the absolute sanction unworkable and again allowed early abortions. 300 years would pass before the Catholic church under Pius IX again declared all abortion murder. This standard, declared in 1869, remains the official position of the church, reaffirmed by the current pope. In 1920 the Soviet Union became the 1st modern state formally to legalize abortion. In the early period after the 1917 revolution, abortion was readily available in state operated facilities. These facilities were closed and abortion made illegal when it became clear that the Soviet Union would have to defend itself against Nazi Germany. After World War II women were encouraged to enter the labor force, and abortion once again became legal. The cases of the Catholic church and the Soviet Union illustrate the same point. Abortion legislation has never been in the hands of women. In the 20th century, state policy has been determined by the rhythms of economic and military expansion, the desire for cheap

  7. Religion and attitudes toward abortion and abortion policy in Brazil.

    PubMed

    Ogland, Curtis P; Verona, Ana Paula

    2011-01-01

    This study examines the association between religion and attitudes toward the practice of abortion and abortion policy in Brazil. Drawing upon data from the 2002 Brazilian Social Research Survey (BSRS), we test a number of hypotheses with regard to the role of religion on opposition to the practice of abortion and its legalization. Findings indicate that frequently attending Pentecostals demonstrate the strongest opposition to the practice of abortion and both frequently attending Pentecostals and Catholics demonstrate the strongest opposition to its legalization. Additional religious factors, such as a commitment to biblical literalism, were also found to be significantly associated with opposition to both abortion issues. Ultimately, the findings have implications for the future of public policy on abortion and other contentious social issues in Brazil.

  8. Use of phages against antibiotic-resistant Staphylococcus aureus isolated from bovine mastitis.

    PubMed

    Dias, R S; Eller, M R; Duarte, V S; Pereira, Â L; Silva, C C; Mantovani, H C; Oliveira, L L; Silva, E de A M; De Paula, S O

    2013-08-01

    Bovine mastitis is the primary disease of dairy cattle worldwide and it causes large economic losses. Among several microorganisms that are the causative agents of this disease, Staphylococcus aureus is the most prevalent. Although antibiotic therapy is still the most widely used procedure for the treatment of bovine mastitis, alternative means of treatment are necessary due to the presence of antibiotic residues in milk, which is a growing concern because of its interference with the production of milk derivatives and the selection of resistant bacterial strains. The use of bacteriophages as a tool for the control of pathogens is an alternative treatment to antibiotic therapy. In this work, to obtain phages with the potential for use in phage therapy as a treatment for mastitis, we isolated and identified the bacteria from the milk of mastitis-positive cows. A total of 19% of the animals from small and medium farms of the Zona da Mata Mineira, Brazil, was positive for bovine mastitis, and bacteria of the genus Staphylococcus were the most prevalent pathogens. The majority of the S. aureus isolates tested was resistant to penicillin and ampicillin. In parallel, we isolated 10 bacteriophages able to infect some of these S. aureus isolates. We determined that these phages contained DNA genomes of approximately 175 kb in length, and the protein profiles indicated the presence of 4 major proteins. Electron microscopy revealed that the phages are caudate and belong to the Myoviridae family. The isolates exhibited interesting features for their use in phage therapy such as a high lytic potential, a wide range of hosts, and thermostability, all of which favor their use in the field.

  9. New Small Polypeptides Associated with DNA-Dependent RNA Polymerase of Escherichia coli after Infection with Bacteriophage T4

    PubMed Central

    Stevens, Audrey

    1972-01-01

    Four new small polypeptides are associated with DNA-dependent RNA polymerase from E. coli after infection with T4 phage. The new polypeptides are easily detected in RNA polymerase from E. coli cells labeled with amino acids after phage infection. Their molecular weights range from 10,000 to 22,000, as detected by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. All four polypeptides are found after infection with either wild-type T4 phage or T4 early amber mutants in genes 44, 42, 47, and 46. None of the polypeptides is labeled significantly before 5 min after infection at 30°. When two maturation-defective amber mutants in gene 55 of T4 phage are used for infection, a polypeptide with a molecular weight of 22,000 is absent. When a maturation-defective amber mutant in gene 33 of T4 phage is used, another small protein is absent. PMID:4551978

  10. Abortion trends from 1996 to 2011 in Estonia: special emphasis on repeat abortion

    PubMed Central

    2014-01-01

    Background The study aimed to describe the overall and age-specific trends of induced abortions from 1996 to 2011 with an emphasis on socio-demographic characteristics and contraceptive use of women having had repeat abortions in Estonia. Methods Data were retrieved from the Estonian Medical Birth and Abortion Registry and Statistics Estonia. Total induced abortion numbers, rates, ratios and age-specific rates are presented for 1996–2011. The percentage change in the number of repeat abortions within selected socio-demographic subgroups, contraception use and distribution of induced abortions among Estonians and non-Estonians for the first, second, third, fourth and subsequent abortions were calculated for the periods 1996–2003 and 2004–2011. Results Observed trends over the 16-year study period indicated a considerable decline in induced abortions with a reduction in abortion rate of 57.1%, which was mainly attributed to younger cohorts. The percentage of women undergoing repeat abortions fell steadily from 63.8% during 1996–2003 to 58.0% during 2004–2011. The percentage of women undergoing repeat abortions significantly decreased over the 16 years within all selected socio-demographic subgroups except among women with low educational attainment and students. Within each time period, a greater percentage of non-Estonians than Estonians underwent repeat abortions and obtained third and subsequent abortions. Most women did not use any contraceptive method prior to their first or subsequent abortion. Conclusion A high percentage of women obtaining repeat abortions reflects a high historical abortion rate. If current trends continue, a rapid decline in repeat abortions may be predicted. To decrease the burden of sexual ill health, routine contraceptive counselling, as standard care in the abortion process, should be seriously addressed with an emphasis on those groups - non-Estonians, women with lower educational attainment, students and women with children

  11. Effect of abortion protesters on women's emotional response to abortion.

    PubMed

    Foster, Diana Greene; Kimport, Katrina; Gould, Heather; Roberts, Sarah C M; Weitz, Tracy A

    2013-01-01

    Little is known about women's experiences with and reactions to protesters and how protesters affect women's emotional responses to abortion. We interviewed 956 women seeking abortion between 2008 and 2010 at 30 U.S. abortion care facilities and informants from 27 of these facilities. Most facilities reported a regular protester presence; one third identified protesters as aggressive towards patients. Nearly half (46%) of women interviewed saw protesters; of those, 25% reported being "a little" upset, and 16% reported being "quite a lot" or "extremely" upset. Women who had difficulty deciding to abort had higher odds of reporting being upset by protesters. In multivariable models, exposure to protesters was not associated with differences in emotions 1 week after the abortion. Protesters do upset some women seeking abortion services. However, exposure to protesters does not seem to have an effect on women's emotions about the abortion 1 week later. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Misinformation on abortion.

    PubMed

    Rowlands, Sam

    2011-08-01

    To find the latest and most accurate information on aspects of induced abortion. A literature survey was carried out in which five aspects of abortion were scrutinised: risk to life, risk of breast cancer, risk to mental health, risk to future fertility, and fetal pain. Abortion is clearly safer than childbirth. There is no evidence of an association between abortion and breast cancer. Women who have abortions are not at increased risk of mental health problems over and above women who deliver an unwanted pregnancy. There is no negative effect of abortion on a woman's subsequent fertility. It is not possible for a fetus to perceive pain before 24 weeks' gestation. Misinformation on abortion is widespread. Literature and websites are cited to demonstrate how data have been manipulated and misquoted or just ignored. Citation of non-peer reviewed articles is also common. Mandates insisting on provision of inaccurate information in some US State laws are presented. Attention is drawn to how women can be misled by Crisis Pregnancy Centres. There is extensive promulgation of misinformation on abortion by those who oppose abortion. Much of this misinformation is based on distorted interpretation of the scientific literature.

  13. Oligopeptide M13 Phage Display in Pathogen Research

    PubMed Central

    Kügler, Jonas; Zantow, Jonas; Meyer, Torsten; Hust, Michael

    2013-01-01

    Phage display has become an established, widely used method for selection of peptides, antibodies or alternative scaffolds. The use of phage display for the selection of antigens from genomic or cDNA libraries of pathogens which is an alternative to the classical way of identifying immunogenic proteins is not well-known. In recent years several new applications for oligopeptide phage display in disease related fields have been developed which has led to the identification of various new antigens. These novel identified immunogenic proteins provide new insights into host pathogen interactions and can be used for the development of new diagnostic tests and vaccines. In this review we focus on the M13 oligopeptide phage display system for pathogen research but will also give examples for lambda phage display and for applications in other disease related fields. In addition, a detailed technical work flow for the identification of immunogenic oligopeptides using the pHORF system is given. The described identification of immunogenic proteins of pathogens using oligopeptide phage display can be linked to antibody phage display resulting in a vaccine pipeline. PMID:24136040

  14. Oligopeptide m13 phage display in pathogen research.

    PubMed

    Kügler, Jonas; Zantow, Jonas; Meyer, Torsten; Hust, Michael

    2013-10-16

    Phage display has become an established, widely used method for selection of peptides, antibodies or alternative scaffolds. The use of phage display for the selection of antigens from genomic or cDNA libraries of pathogens which is an alternative to the classical way of identifying immunogenic proteins is not well-known. In recent years several new applications for oligopeptide phage display in disease related fields have been developed which has led to the identification of various new antigens. These novel identified immunogenic proteins provide new insights into host pathogen interactions and can be used for the development of new diagnostic tests and vaccines. In this review we focus on the M13 oligopeptide phage display system for pathogen research but will also give examples for lambda phage display and for applications in other disease related fields. In addition, a detailed technical work flow for the identification of immunogenic oligopeptides using the pHORF system is given. The described identification of immunogenic proteins of pathogens using oligopeptide phage display can be linked to antibody phage display resulting in a vaccine pipeline.

  15. Abortion.

    PubMed

    Cattanach, J F

    1979-03-10

    As abortion is the destruction of individual human life, if an abortion is to be performed at all there must be grave reasons for it which should necessitate complete documentation. Surely human life should be given that respect at least. Legislation should oblige any doctor intending to perform an induced abortion to list the indications which in his or her opinion make that abortion lawful. A signed copy of that opinion should be sent to an official authority of notification. This authority could be developed along the lines of the Neonatal Deaths Committees with authority to check any such notification through consultant tribunals, similar to those existing in New Zealand, which would have access to the patient. The simplest way to ensure that an induced abortion of a viable pregnancy has not occurred at any curettage is to pass legislation which would make it mandatory that all tissue obtained at all uterine curettages or evacuations be sent for histopathological examination. Should the pathologist find evidence of an induced abortion or hysterotomy a copy of the pathology report would then be sent to the official committee. The usual copies would be sent to the doctor and hospital concerned. All such procedures would have to be carried out at registered hospitals. All medical staff members and nurses would have access to such reports. It would be a grave offence for the doctor, pathologist or hospital not to comply with the above procedure. The official committee would have the power to demand samples of tissue for examination by its own consultant pathologist, and to investigate irregularities in the above procedure. Pathologists concur that induced abortion can be accurately differentiated from other types of abortion, as there is an infiltration of polymorphs into the decidua within about three hours of fetal death in incomplete abortion, and there are other features such as hyalinization of placental villi. Apparently, these differences are so basic that a

  16. Dark recovery of uv-irradiated phage TI. I. A minor recovery effect whose exclusion permits the study of survival kinetics under presumably repairless conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Harm, W.

    1973-12-01

    The survival of uv-irradiated phage Tl is much lower in excision repair- deficient than in excision repair-proficient E.coli cells, due to lack of host ceH reactivation (HCR). sn additional decrease in phage survival occurs when repair-deficient (HCR-) host cells have been exposed to uv doses from 3000 to 10,000 erg mm/-sup 2/ of 254 nm uv radiation prior to infection. The observed effect is attributed to loss of a minor phage recovery process, which requires neither the bacterial excision repair nor the bacterial REC repair system. This type of recovery is little affected by caffeine or acriflavine at concentrations thatmore » preclude HCR completely. Its full inhibition by uv-irradiation of the cells requires on approximately 8 times larger dose than complete inhibition of HCR. In heavily preirradiated cells, the TI burst size is extremely small and multiplicity reactivation is considerably less extensive than in unirradiated cells. Presumably the survival of singly infecting Tl in these cells reflects absence of any type of repair. The observed phage sensitivity and shape of the curve are compatible with the expectation for completely repairless conditions. The mechanism underlying the minor recovery is not known; theoretical considerations make a phage REC repair mechanism seem likely. (auth)« less

  17. Population Group Abortion Rates and Lifetime Incidence of Abortion: United States, 2008-2014.

    PubMed

    Jones, Rachel K; Jerman, Jenna

    2017-12-01

    To assess the prevalence of abortion among population groups and changes in rates between 2008 and 2014. We used secondary data from the Abortion Patient Survey, the American Community Survey, and the National Survey of Family Growth to estimate abortion rates. We used information from the Abortion Patient Survey to estimate the lifetime incidence of abortion. Between 2008 and 2014, the abortion rate declined 25%, from 19.4 to 14.6 per 1000 women aged 15 to 44 years. The abortion rate for adolescents aged 15 to 19 years declined 46%, the largest of any group. Abortion rates declined for all racial and ethnic groups but were larger for non-White women than for non-Hispanic White women. Although the abortion rate decreased 26% for women with incomes less than 100% of the federal poverty level, this population had the highest abortion rate of all the groups examined: 36.6. If the 2014 age-specific abortion rates prevail, 24% of women aged 15 to 44 years in that year will have an abortion by age 45 years. The decline in abortion was not uniform across all population groups.

  18. Large outbreak of salmonella phage type 1 infection with high infection rate and severe illness associated with fast food premises.

    PubMed

    Giraudon, I; Cathcart, S; Blomqvist, S; Littleton, A; Surman-Lee, S; Mifsud, A; Anaraki, S; Fraser, G

    2009-06-01

    To describe the epidemiology of an outbreak of Salmonella enteritidis phage type 1 (PT1) infection associated with a fast food premises, and to identify the causative factors leading to an acute outbreak with high attack rate and severe illness including hospital admission. Integrated descriptive study of epidemiology, food and environmental microbiology, and professional environmental health assessment, supplemented by a case-case analytical study. Cases were identified through multiple sources and were interviewed to identify food items consumed. Descriptive epidemiology of all cases and a case-case analytical study of risk factors for severe illness were undertaken. Microbiological investigation included analysis and typing of pathogens from stools, blood and environmental surfaces. Professional environmental heath assessment of the premises was undertaken. S. enteritidis PT1 was recovered from two-thirds of faecal samples. Three cases had dual infection with enterotoxin-producing Clostridium perfringens. S. enteritidis PT1 was isolated from 14 of 40 food samples examined and C. perfringens was isolated from eight food samples. Environmental health inspection of the premises revealed multiple deficiencies, including deficits in food preparation and hygiene consistent with multiple cross-contamination, and time-temperature abuse of sauces widely used across menu items. Severe cases were associated with consumption of chips and salad. Outbreaks from fast food premises have been infrequently described. This outbreak demonstrates the potential for fast food premises, with multiple deficiencies in food preparation and hygiene, to produce large, intense community outbreaks with high attack rates and severe illness, highly confined in space and time.

  19. [Demand for abortion. Pre-abortion discussion].

    PubMed

    Guiol, L

    1994-03-01

    The preabortion interview required by French law takes place between the medical consultation and the aspiration or administration of RU-486. The three marriage counselors at the Center for Social Gynecology in Marseilles have each undertaken a course of personal therapy to enable them to understand their own reactions and motivations as a way of improving their effectiveness with clients. The preabortion interview is an opportunity to listen to and support women who may be experiencing anguish, sadness, ambivalence, or aggressivity. Each client determines the content of the interview. Often the reason for the abortion is given, frequently in terms of economic problems, unemployment, or other justification. The women almost always state that they "cannot", not that they "do not want", to continue the pregnancy, as if external circumstances had made their decision. The decision is usually made with little discussion. Young adolescents are often astounded to find themselves pregnant. Among young girls, the pregnancy may represent an appeal to the parents for attention or understanding. Sometimes the abortion represents a repetition or a reminder of some difficult event in the past, such as a previous abortion or the death of a child. Often the abortion exacerbates problems in the couple's relationship. The mother often experiences rejection of the pregnancy by the father as rejection of herself. Repeat abortions raise questions about whether some aspect of counseling was neglected. The abortion request always occasions a great feeling of guilt, both for being pregnant and for refusing the pregnancy. The interview permits the client to express her feelings and may help her make sense of the experience.

  20. Update on abortion policy.

    PubMed

    Conti, Jennifer A; Brant, Ashley R; Shumaker, Heather D; Reeves, Matthew F

    2016-12-01

    To review the status of antiabortion restrictions enacted over the last 5 years in the United States and their impact on abortion services. In recent years, there has been an alarming rise in the number of antiabortion laws enacted across the United States. In total, various states in the union enacted 334 abortion restrictions from 2011 to July 2016, accounting for 30% of all abortion restrictions since the legalization of abortion in 1973. Data confirm, however, that more liberal abortion laws do not increase the number of abortions, but instead greatly decrease the number of abortion-related deaths. Several countries including Romania, South Africa and Nepal have seen dramatic decreases in maternal mortality after liberalization of abortion laws, without an increase in the total number of abortions. In the United States, abortions are incredibly safe with very low rates of complications and a mortality rate of 0.7 per 100 000 women. With increasing abortion restrictions, maternal mortality in the United States can be expected to rise over the coming years, as has been observed in Texas recently. Liberalization of abortion laws saves women's lives. The rising number of antiabortion restrictions will ultimately harm women and their families.

  1. A novel helper phage for HaloTag-mediated co-display of enzyme and substrate on phage.

    PubMed

    Delespaul, Wouter; Peeters, Yves; Herdewijn, Piet; Robben, Johan

    2015-05-01

    Phage display is an established technique for the molecular evolution of peptides and proteins. For the selection of enzymes based on catalytic activity however, simultaneous coupling of an enzyme and its substrate to the phage surface is required. To facilitate this process of co-display, we developed a new helper phage displaying HaloTag, a modified haloalkane dehalogenase that binds specifically and covalently to functionalized haloalkane ligands. The display of functional HaloTag was demonstrated by capture on streptavidin-coated magnetic beads, after coupling a biotinylated haloalkane ligand, or after on-phage extension of a DNA oligonucleotide primer with a biotinylated nucleotide by phi29 DNA polymerase. We also achieved co-display of HaloTag and phi29 DNA polymerase, thereby opening perspectives for the molecular evolution of this enzyme (and others) towards new substrate specificities. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. A kinetic analysis of DNA ejection from tailed phages revealing the prerequisite activation energy.

    PubMed

    Raspaud, Eric; Forth, Thomas; São-José, Carlos; Tavares, Paulo; de Frutos, Marta

    2007-12-01

    All tailed bacteriophages follow the same general scheme of infection: they bind to their specific host receptor and then transfer their genome into the bacterium. DNA translocation is thought to be initiated by the strong pressure due to DNA packing inside the capsid. However, the exact mechanism by which each phage controls its DNA ejection remains unknown. Using light scattering, we analyzed the kinetics of in vitro DNA release from phages SPP1 and lambda (Siphoviridae family) and found a simple exponential decay. The ejection characteristic time was studied as a function of the temperature and found to follow an Arrhenius law, allowing us to determine the activation energy that governs DNA ejection. A value of 25-30 kcal/mol is obtained for SPP1 and lambda, comparable to the one measured in vitro for T5 (Siphoviridae) and in vivo for T7 (Podoviridae). This suggests similar mechanisms of DNA ejection control. In all tailed phages, the opening of the connector-tail channel is needed for DNA release and could constitute the limiting step. The common value of the activation energy likely reflects the existence for all phages of an optimum value, ensuring a compromise between efficient DNA delivery and high stability of the virus.

  3. Serologic and reproductive findings after a herpesvirus-1 abortion storm in goats.

    PubMed

    McCoy, Morgan H; Montgomery, Donald L; Bratanich, Ana C; Cavender, Jacque; Scharko, Patricia B; Vickers, Mary Lynne

    2007-10-15

    An abortion storm occurred in a goat herd, resulting in 75 aborted kids and 1 neonatal death from December 2004 to February 2005. Aborted fetuses ranged from being premature to past term. Laboratory findings in 4 of 5 aborted fetuses were consistent with herpesvirus abortion. A virus that yielded positive results with a fluorescent antibody test for bovine herpesvirus-1 was isolated and identified as caprine herpesvirus-1 (CpHV-1) via DNA sequence analysis. Many does that aborted were rebred for kidding in late summer. Most of the young wethers born in 2005 were sold; however, all of the young does were kept for breeding in fall. In November 2005, all 241 goats in the herd were tested for antibodies against CpHV-1 to identify goats that had seroconverted during the outbreak. No complications attributable to CpHV-1 were identified during kidding in 2006. On the basis of serologic findings, infection with CpHV-1 was not associated with reduced reproductive success in the subsequent breeding.

  4. Somatostatin displayed on filamentous phage as a receptor-specific agonist

    PubMed Central

    Rousch, Mat; Lutgerink, Jan T; Coote, James; de Bruïne, Adriaan; Arends, Jan-Willem; Hoogenboom, Hennie R

    1998-01-01

    In search of methods to identify bio-active ligands specific for G protein-coupled receptors with seven transmembrane spanning regions, we have developed a filamentous phage-based selection and functional screening method. First, methods for panning peptide phage on cells were established, using the hormone somatostatin as a model. Somatostatin was displayed on the surface of filamentous phage by cloning into phage(mid) vectors and fusion to either pIII or pVIII viral coat proteins. Peptide displaying phage bound to a polyclonal anti-somatostatin serum, and, more importantly, to several somatostatin receptor subtypes (Sst) expressed on transfected CHO-K1 cells, in a pattern which was dependent on the used display method. Binding was competed with somatostatin, with an IC50 in the nanomolar range. The phage were specifically enriched by panning on cells, establishing conditions for cell selections of phage libraries. Binding of somatostatin displaying phage to sst2 on a reporter cell line, in which binding of natural ligand reduces secretion of alkaline phosphatase (via a cyclic AMP responsive element sensitive promoter), proved that the phage particles act as receptor-specific agonists. Less than 100 phage particles per cell were required for this activity, which is approximately 1000 fold less than soluble somatostatin, suggesting that phage binding interferes with normal receptor desensitization and/or recycling. The combination of biopanning of phage libraries on cells with functional screening of phage particles for receptor triggering activity, may be used to select novel, bio-active ligands from phage libraries of random peptides, antibody fragments, or libraries based on the natural receptor ligand. PMID:9776337

  5. Differentiation of Salmonella enteritidis phage type 8 strains: evaluation of three additional phage typing systems, plasmid profiles, antibiotic susceptibility patterns, and biotyping.

    PubMed Central

    Stubbs, A D; Hickman-Brenner, F W; Cameron, D N; Farmer, J J

    1994-01-01

    Three additional phage typing systems for Salmonella enteritidis, plasmid analysis, biochemical tests, and antimicrobial susceptibility tests, were used in an attempt to subdivide 30 phage type 8 (phage typing system used by the WHO International Center for Enteric Phage Typing, London, England) isolates. These isolates represented 18 different egg-related outbreaks (21 strains) and 9 reference strains or strains that were not egg-associated. Only 7 of the 30 strains (28%) were subdivided by one or more of the methods used; this included 3 of the 21 strains from egg-related outbreaks. Twenty-seven strains contained a 55-kb plasmid that is associated with S. enteritidis. Of 65 additional phages tested, 2 from the phage typing system obtained from the Pasteur Institute, Paris, France, were useful in differentiating the three strains that lacked the 55-kb plasmid. Although the results obtained for the 21 strains from egg-related outbreaks showed that the strains had minor phenotypic differences, the overall results suggested that the strains may represent a single clone. Studies are planned to test additional phages and other typing methods to see whether strains of phage type 8 can be further differentiated. PMID:8126179

  6. Phage protein-targeted cancer nanomedicines

    PubMed Central

    Petrenko, V.A.; Jayanna, P.K.

    2015-01-01

    Nanoencapsulation of anticancer drugs improves their therapeutic indices by virtue of the enhanced permeation and retention effect which achieves passive targeting of nanoparticles in tumors. This effect can be significantly enhanced by active targeting of nanovehicles to tumors. Numerous ligands have been proposed and used in various studies with peptides being considered attractive alternatives to antibodies. This is further reinforced by the availability of peptide phage display libraries which offer an unlimited reservoir of target-specific probes. In particular landscape phages with multivalent display of target-specific peptides which enable the phage particle itself to become a nanoplatform creates a paradigm for high throughput selection of nanoprobes setting the stage for personalized cancer management. Despite its promise, this conjugate of combinatorial chemistry and nanotechnology has not made a significant clinical impact in cancer management due to a lack of using robust processes that facilitate scale-up and manufacturing. To this end we proposed the use of phage fusion protein as the navigating modules of novel targeted nanomedicine platforms which are described in this review. PMID:24269681

  7. Public funding of abortions and abortion counseling for poor women.

    PubMed

    Edwards, R B

    1997-01-01

    This essay seeks to reveal the weakness in arguments against public funding of abortions and abortion counseling in the US based on economic, ethico-religious, anti-racist, and logical-consistency objections and to show that public funding of abortion is strongly supported by appeals to basic human rights, to freedom of speech, to informed consent, to protection from great harm, to justice, and to equal protection under the law. The first part of the article presents the case against public funding with detailed considerations of the economic argument, the ethico/religious argument, the argument that such funding supports racist genocide or eugenic quality control, and arguments that a logical inconsistency exists between the principles used to justify the legalization of abortions and arguments for public funding. The second part of the article presents the case for public funding by discussing the spending of public funds on morally offensive programs, arguments for public funding of abortion counseling for the poor, and arguments for public funding of abortions for the poor. It is concluded that it is morally unacceptable and rationally unjustifiable to refuse to expend public funds for abortions for low income women, because after all most money for legal abortions for the poor comes from welfare payments made to women. If conservative forces want to insure that no public funds pay for abortions, they must stop all welfare payments to pregnant women.

  8. Accounting for abortion: Accomplishing transnational reproductive governance through post-abortion care in Senegal.

    PubMed

    Suh, Siri

    2018-06-01

    Reproductive governance operates through calculating demographic statistics that offer selective truths about reproductive practices, bodies, and subjectivities. Post-abortion care, a global reproductive health intervention, represents a transnational reproductive regime that establishes motherhood as women's primary legitimate reproductive status. Drawing on ethnographic fieldwork conducted in Senegal between 2010 and 2011, I illustrate how post-abortion care accomplishes reproductive governance in a context where abortion is prohibited altogether and the US is the primary bilateral donor of population aid. Reproductive governance unfolds in hospital gynecological wards and the national health information system through the mobilization and interpretation of post-abortion care data. Although health workers search women's bodies and behavior for signs of illegal abortion, they minimize police intervention in the hospital by classifying most post-abortion care cases as miscarriage. Health authorities deploy this account of post-abortion care to align the intervention with national and global maternal health policies that valorize motherhood. Although post-abortion care offers life-saving care to women with complications of illegal abortion, it institutionalizes abortion stigma by scrutinizing women's bodies and masking induced abortion within and beyond the hospital. Post-abortion care reinforces reproductive inequities by withholding safe, affordable obstetric care from women until after they have resorted to unsafe abortion.

  9. Phage as a template to grow bone mineral nanocrystals.

    PubMed

    Cao, Binrui; Xu, Hong; Mao, Chuanbin

    2014-01-01

    Phage display is a biotechnique that fuses functional peptides on the outer surface of filamentous phage by inserting DNA encoding the peptides into the genes of its coat proteins. The resultant peptide-displayed phage particles have been widely used as biotemplates for the synthesis of functional hybrid nanomaterials. Here, we describe the bioengineering of M13 filamentous phage to surface-display bone mineral (hydroxyapatite (HAP))-nucleating peptides derived from dentin matrix protein-1 and using the engineered phage as a biotemplate to grow HAP nanocrystals.

  10. Significant Adverse Events and Outcomes After Medical Abortion

    PubMed Central

    Cleland, Kelly; Creinin, Mitchell D.; Nucatola, Deborah; Nshom, Montsine; Trussell, James

    2013-01-01

    Objective To analyze rates of significant adverse events and outcomes in women having a medical abortion at Planned Parenthood health centers in 2009 and 2010, and to identify changes in the rates of adverse events and outcomes between the 2 years. Methods In this database review we analyzed data from Planned Parenthood affiliates that provided medical abortion in 2009 and 2010, almost exclusively using an evidence-based buccal misoprostol regimen. We evaluated the incidence of six clinically significant adverse events (hospital admission, blood transfusion, emergency room treatment, intravenous antibiotics administration, infection, and death) and two significant outcomes (ongoing pregnancy and ectopic pregnancy diagnosed after medical abortion treatment was initiated). We calculated an overall rate as well as rates for each event and identified changes between the 2 years. Results Amongst 233,805 medical abortions provided in 2009 and 2010, significant adverse events or outcomes were reported in 1,530 cases (0.65%). There was no statistically significant difference in overall rates between years. The most common significant outcome was ongoing intrauterine pregnancy (0.50%); significant adverse events occurred in 0.16% of cases. One patient death occurred due to an undiagnosed ectopic pregnancy. Only rates for emergency room treatment and blood transfusion differed by year, and were slightly higher in 2010. Conclusion Review of this large dataset reinforces the safety of the evidence-based medical abortion regimen. PMID:23262942

  11. The genomes and comparative genomics of Lactobacillus delbrueckii phages.

    PubMed

    Riipinen, Katja-Anneli; Forsman, Päivi; Alatossava, Tapani

    2011-07-01

    Lactobacillus delbrueckii phages are a great source of genetic diversity. Here, the genome sequences of Lb. delbrueckii phages LL-Ku, c5 and JCL1032 were analyzed in detail, and the genetic diversity of Lb. delbrueckii phages belonging to different taxonomic groups was explored. The lytic isometric group b phages LL-Ku (31,080 bp) and c5 (31,841 bp) showed a minimum nucleotide sequence identity of 90% over about three-fourths of their genomes. The genomic locations of their lysis modules were unique, and the genomes featured several putative overlapping transcription units of genes. LL-Ku and c5 virions displayed peptidoglycan hydrolytic activity associated with a ~36-kDa protein similar in size to the endolysin. Unexpectedly, the 49,433-bp genome of the prolate phage JCL1032 (temperate, group c) revealed a conserved gene order within its structural genes. Lb. delbrueckii phages representing groups a (a phage LL-H), b and c possessed only limited protein sequence homology. Genomic comparison of LL-Ku and c5 suggested that diversification of Lb. delbrueckii phages is mainly due to insertions, deletions and recombination. For the first time, the complete genome sequences of group b and c Lb. delbrueckii phages are reported.

  12. Advances in the T7 phage display system (Review).

    PubMed

    Deng, Xiangying; Wang, Li; You, Xiaolong; Dai, Pei; Zeng, Yanhua

    2018-01-01

    The present review describes the advantages and updated applications of the T7 phage display system in bioscience and medical science. Current phage display systems are based on various bacteriophage vectors, including M13, T7, T4 and f1. Of these, the M13 phage display is the most frequently used, however, the present review highlights the advantages of the T7 system. As a phage display platform, M13 contains single‑stranded DNA, while the T7 phage consists of double‑stranded DNA, which exhibits increased stability and is less prone to mutation during replication. Additional characteristics of the T7 phage include the following: The T7 phage does not depend on a protein secretion pathway in the lytic cycle; expressed peptides and proteins are usually located on the C‑terminal region of capsid protein gp10B, which avoids problems associated with steric hindrance; and T7 phage particles exhibit high stability under various extreme conditions, including high temperature and low pH, which facilitates effective high‑throughput affinity elutriation. Recent applications of the T7 phage display system have been instrumental in uncovering mechanisms of molecular interaction, particularly in the fields of antigen discovery, vaccine development, protein interaction, and cancer diagnosis and treatment.

  13. Consumer attitudes and behaviours--key risk factors in an outbreak of Salmonella typhimurium phage type 12 infection sourced to chicken nuggets.

    PubMed

    Kenny, B; Hall, R; Cameron, S

    1999-04-01

    To identify the source and intervention methods for an outbreak of Salmonella Typhimurium phage type 12 in South Australia. Ten cases of S. Typhimurium phage type (PT) 12 infection were notified in South Australia in a four-week period from 7 May 1998. Nine cases and 27 controls were included in a case control study to test the hypothesis that illness was associated with the consumption of chicken nuggets. A significant association between illness and the consumption of one brand of chicken nuggets was determined, odds ratio undefined (95% CI undefined; p = undefined). Nine of nine cases and one of 27 controls reported eating these chicken nuggets. S. Typhimurium PT 12 was isolated from an opened sample of this particular brand of nuggets which had been retrieved from the home of one case. The implicated nuggets were essentially a raw product which had been 'flash fried' in contrast with other brands which were fully cooked. The investigation highlighted issues of inadequate labelling and consumer responses to labelling information which affect food safety. A media release to highlight to the consumer the need to cook frozen food properly and a voluntary recall of the 'flash fried' product was instigated as a result of these conclusions. Further action is needed to eliminate the potential hazard that consumers will perceive and handle 'flash fried' nuggets as if they are a cooked chicken product.

  14. Comparative analysis of multiple inducible phages from Mannheimia haemolytica.

    PubMed

    Niu, Yan D; Cook, Shaun R; Wang, Jiaying; Klima, Cassidy L; Hsu, Yu-hung; Kropinski, Andrew M; Turner, Dann; McAllister, Tim A

    2015-08-30

    Mannheimia haemolytica is a commensal bacterium that resides in the upper respiratory tract of cattle that can play a role in bovine respiratory disease. Prophages are common in the M. haemolytica genome and contribute significantly to host diversity. The objective of this research was to undertake comparative genomic analysis of phages induced from strains of M. haemolytica serotype A1 (535A and 2256A), A2 (587A and 1127A) and A6 (1152A and 3927A). Overall, four P2-like (535AP1, 587AP1, 1127AP1 and 2256AP1; genomes: 34.9-35.7 kb; G+C content: 41.5-42.1 %; genes: 51-53 coding sequences, CDSs), four λ-like (535AP2, 587AP2, 1152AP2 and 3927AP1; genomes: 48.6-52.1 kb; 41.1-41.4 % mol G+C; genes: 77-83 CDSs and 2 tRNAs) and one Mu-like (3927AP2; genome: 33.8 kb; 43.1 % mol G+C; encoding 50 CDSs) phages were identified. All P2-like phages are collinear with the temperate phage φMhaA1-PHL101 with 535AP1, 2256AP1 and 1152AP1 being most closely related, followed by 587AP1 and 1127AP1. Lambdoid phages are not collinear with any other known λ-type phages, with 587AP2 being distinct from 535AP2, 3927AP1 and 1152AP2. All λ-like phages contain genes encoding a toxin-antitoxin (TA) system and cell-associated haemolysin XhlA. The Mu-like phage induced from 3927A is closely related to the phage remnant φMhaMu2 from M. haemolytica PHL21, with similar Mu-like phages existing in the genomes of M. haemolytica 535A and 587A. This is among the first reports of both λ- and Mu-type phages being induced from M. haemolytica. Compared to phages induced from commensal strains of M. haemolytica serotype A2, those induced from the more virulent A1 and A6 serotypes are more closely related. Moreover, when P2-, λ- and Mu-like phages co-existed in the M. haemolytica genome, only P2- and λ-like phages were detected upon induction, suggesting that Mu-type phages may be more resistant to induction. Toxin-antitoxin gene cassettes in λ-like phages may contribute to their genomic

  15. Trying to prevent abortion.

    PubMed

    Bromham, D R; Oloto, E J

    1997-06-01

    It is known that, since antiquity, women confronted with an unwanted pregnancy have used abortion as a means of resolving their dilemma. Although undoubtedly widely used in all historical ages, abortion has come to be regarded as an event preferably avoided because of the impact on the women concerned as well as considerations for fetal life. Policies to reduce numbers and rates of abortion must acknowledge certain observations. Criminalization does not prevent abortion but increases maternal risks. A society's 'openness' in discussing sexual matters inversely correlates with abortion rates. Correlation between contraceptive use and abortion is also inverse but relates most closely to the efficacy of contraceptive methods used. 'Revolution' in the range of contraceptive methods used will have an equivalent impact on abortion rates. Secondary or emergency contraceptive methods have a considerable role to play in the reduction of abortion numbers. Good sex (and 'relationships') education programs may delay sexual debut, increase contraceptive usage and be associated with reduced abortion. Finally, interaction between socioeconomic factors and the choice between abortion and ongoing pregnancy are complex. Abortion is not necessarily chosen by those least able to support a child financially.

  16. [Abortion in Japan].

    PubMed

    Yamamoto, K; Yamamoto, Y; Hayase, T

    1993-01-01

    In Japan, the artificial abortion is a penal offence; only in the presence of certain conditions it is authorized under the provision of the Eugenic Protection Law which was promulgated in 1948. According to the law, the artificial abortion is restricted to the period, in which the fetus is not viable outside of the uterus. This period is prescribed by notification from the Ministry of Public Welfare; up to now it has been shortened twice (1976, 1991). Due to the introduction of economic reasons in the list of conditions and the simplification of the procedure the artificial abortion in Japan was virtually liberalized. Prosecution for illegal abortion is very rare in recent years. The number of reported artificial abortions decreases; in the about last 30 years it reduced by half. However, the increase in the number of abortions in women younger than 20 years of age is a problem. The abortion in teenagers is late compared with that in other age groups. Although the number of neonaticides does not seem to increase, the increase in the number of abortions in teenagers remains a serious problem in Japan.

  17. Morphological evidence for phages in Xylella fastidiosa

    PubMed Central

    Chen, Jianchi; Civerolo, Edwin L

    2008-01-01

    Presumptive phage particles associated with Xylella fastidiosa strain Temecula-1 grown in PW broth were observed by transmission electron microscopy (TEM) in ultrathin sections of bacterial cell-containing low speed centrifugation pellets and in partially purified preparations from CsCl equilibrium centrifugation density gradients. Ultrathin-sectioned cell pellets contained icosahedral particles of about 45 nm in diameter. Samples collected from CsCl density gradients revealed mostly non-tailed icosahedral but also tailed particles. The icosahedral particles could be divided into two types: a large type (about 45 nm) and a small type (about 30 nm). Filamentous phage-like particles (17 × 120 to 6,300 nm) were also observed. The presence of different types of phage-like particles resembling to those in several bacteriophage families provides new physical evidence, in addition to X. fastidiosa genomic information, that X. fastidiosa possesses active phages. This is the first report of phage particles released in X. fastidiosa cultures. PMID:18538030

  18. Abortion surveillance - United States, 2007.

    PubMed

    Pazol, Karen; Zane, Suzanne; Parker, Wilda Y; Hall, Laura R; Gamble, Sonya B; Hamdan, Saeed; Berg, Cynthia; Cook, Douglas A

    2011-02-25

    Since 1969, CDC has conducted abortion surveillance to document the number and characteristics of women obtaining legal induced abortions in the United States. 2007. Each year, CDC requests abortion data from the central health agencies of 52 reporting areas (the 50 states, the District of Columbia, and New York City). This information is provided voluntarily. For 2007, data were received from 49 reporting areas. For the purpose of trend analysis, data were evaluated from the 45 areas that reported data every year during the preceding decade (1998-2007). Abortion rates (number of abortions per 1,000 women) and ratios (number of abortions per 1,000 live births) were calculated using census and natality data, respectively. A total of 827,609 abortions were reported to CDC for 2007. Among the 45 reporting areas that provided data every year during 1998-2007, a total of 810,582 abortions (97.9% of the total) were reported for 2007; the abortion rate was 16.0 abortions per 1,000 women aged 15-44 years, and the abortion ratio was 231 abortions per 1,000 live births. Compared with 2006, the total number and rate of reported abortions decreased 2%, and the abortion ratio decreased 3%. Reported abortion numbers, rates, and ratios were 6%, 7%, and 14% lower, respectively, in 2007 than in 1998. Women aged 20-29 years accounted for 56.9% of all abortions in 2007 and for the majority of abortions during the entire period of analysis (1998-2007). In 2007, women aged 20-29 years also had the highest abortion rates (29.4 abortions per 1,000 women aged 20-24 years and 21.4 abortions per 1,000 women aged 25-29 years). Adolescents aged 15-19 years accounted for 16.5% of all abortions in 2007 and had an abortion rate of 14.5 abortions per 1,000 adolescents aged 15-19 years; women aged ≥35 years accounted for a smaller percentage (12.0%) of abortions and had lower abortion rates (7.7 abortions per 1,000 women aged 35-39 years and 2.6 abortions per 1,000 women aged ≥40 years

  19. Abortion clinic patients' opinions about obtaining abortions from general women's health care providers.

    PubMed

    Weitz, Tracy Ann; Cockrill, Kate

    2010-12-01

    Most U.S. women obtain abortions at specialty clinics. This qualitative study explores abortion clinic patients' opinions about receiving abortions from general women's health care providers. We conducted 20 h-long, semi-structured interviews with diverse women who had abortions in the U.S. Heartland. Each described her usual health care provider and how she accessed abortion care. We used qualitative analytic methods to organize and interpret the data. Despite having a general provider, most women sought clinic abortions. Some women offered reasons for preferring specialty care and others for preferring abortion from their general provider. Most women assumed their general provider did not "do abortion" and many believed those providers were opposed to abortion. Women who had delivered a baby were concerned with their image in their general provider's eyes. Two women were denied care by their general providers. Women's preferences for abortion care centered on privacy, cost, empathy, ability to control their image, and desire for safe quality care. Two women who sought abortions through their general providers experienced negative repercussions. General providers should proactively make patients aware of their positions on abortion and if supportive indicate that they can provide that care and/or a referral. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  20. Cellular responses in Bacillus thuringiensis CS33 during bacteriophage BtCS33 infection.

    PubMed

    Wu, Dandan; Yuan, Yihui; Liu, Pengming; Wu, Yan; Gao, Meiying

    2014-04-14

    Bacillus thuringiensis (Bt) has been widely used for 50years as a biopesticide for controlling insect pests. However, bacteriophage infection can cause failures in 50%-80% of the batches during Bt fermentation, resulting in severe losses. In the present work, the physiological and biochemical impacts of Bt strain CS33 have been studied during bacteriophage infection. This study adopted a gel-based proteomics approach to probe the sequential changed proteins in phage-infected Bt cells. To phage, it depressed the host energy metabolism by suppressing the respiration chain, the TCA cycle, and the utilization of PHB on one hand; on the other hand, it hijacked the host translational machine for its own macromolecular synthesis. To host, superinfection exclusion might be triggered by the changes of S-layer protein and flagella related proteins, which were located on the cell surface and might play as the candidates for the phage recognition. More importantly, the growth rate, cell mass, and ICPs yield were significantly decreased. The low yield of ICPs was mainly due to the suppressed utilization of PHB granules. Further functional study on these altered proteins may lead to a better understanding of the pathogenic mechanisms and the identification of new targets for phage control. B. thuringiensis (Bt) has been widely used for 50years as a safe biopesticide for controlling agricultural and sanitary insect pests. However, bacteriophage infection can cause severe losses during B. thuringiensis fermentation. The processes and consequences of interactions between bacteriophage and Bt were still poorly understood, and the molecular mechanisms involved were more unknown. This study adopted a gel-based proteomics approach to probe the physiological and biochemical impacts of Bt strain CS33 after phage-infection. The interactions between phage BtCS33 and its host Bt strain CS33 occurred mainly on four aspects. First, phage synthesized its nucleic acids through metabolic

  1. [Abortion].

    PubMed

    Nunes, J P

    1998-01-01

    Abortion is the interruption of a dynamic process in a final and irreversible form. The legalization of abortion is applied to human ontogenesis, that is, the development of the human being. However, the embryo that is growing in the uterus is not a human being because a human being is a complex organism with differentiated systems, its own identity and intrinsic autonomy in its process of development. There are basically four levels of the analysis of the problem of abortion: 1) fundamental emotional arguments; 2) profound ignorance of technical and scientific facts; 3) rational positions obfuscated by the dramatic intensity of everyday situations; and 4) the conjunction of deliberated position where culpability is avoided with solidarity for all subjects of the process with a socially oriented view. The phenomenon of abortion from an epidemiological point of view summons the facts with which it is associated: poverty, illiteracy, shortage or lack of community health resources, absence of centers for adolescents, degradation of the environment, and precariousness of employment.

  2. [Use of contraception and reasons for choosing abortion among abortion applicants].

    PubMed

    Hansen, S K; Birkebaek, J S; Husfeldt, C; Munck, C B; Nøddebo, S M; Petersson, B H

    1996-10-07

    The object of this study was to describe a group of women applying for legal abortion in relation to their use of contraception and reasons for choosing an abortion. During a period of 13 months (1991-92) a questionnaire was distributed to women applying for legal abortion at Hillerød Hospital in Denmark. Three hundred and thirty-nine women participated. Fifty-nine percent of the women had become pregnant although they had used contraception. As seen in other studies, women still state demographic factors as their most important reasons for choosing an abortion. Women with two or more children do not want to have more children. Single women do not want children without being in a stable relationship. Furthermore occupation and education were frequently stated as important reasons for having an abortion. Economy and housing were not main reasons but contributory factors. Thirty percent of the women expressed ambivalence about the choice of abortion at the time when the abort was due.

  3. Post-abortion and induced abortion services in two public hospitals in Colombia.

    PubMed

    Darney, Blair G; Simancas-Mendoza, Willis; Edelman, Alison B; Guerra-Palacio, Camilo; Tolosa, Jorge E; Rodriguez, Maria I

    2014-07-01

    Until 2006, legal induced abortion was completely banned in Colombia. Few facilities are equipped or willing to offer abortion services; often adolescents experience even greater barriers of access in this context. We examined post abortion care (PAC) and legal induced abortion in two large public hospitals. We tested the association of hospital site, procedure type (manual vacuum aspiration vs. sharp curettage), and age (adolescents vs. women 20 years and over) with service type (PAC or legal induced abortion). Retrospective cohort study using 2010 billing data routinely collected for reimbursement (N=1353 procedures). We utilized descriptive statistics, multivariable logistic regression and predicted probabilities. Adolescents made up 22% of the overall sample (300/1353). Manual vacuum aspiration was used in one-third of cases (vs. sharp curettage). Adolescents had lower odds of documented PAC (vs. induced abortion) compared with women over age 20 (OR=0.42; 95% CI=0.21-0.86). The absolute difference of service type by age, however, is very small, controlling for hospital site and procedure type (.97 probability of PAC for adolescents compared with .99 for women 20 and over). Regardless of age, PAC via sharp curettage is the current standard in these two public hospitals. Both adolescents and women over 20 are in need of access to legal abortion services utilizing modern technologies in the public sector in Colombia. Documentation of abortion care is an essential first step to determining barriers to access and opportunities for quality improvement and better health outcomes for women. Following partial decriminalization of abortion in Colombia, in public hospitals nearly all abortion services are post-abortion care, not induced abortion. Sharp curettage is the dominant treatment for both adolescents and women over 20. Women seek care in the public sector for abortion, and must have access to safe, quality services. Copyright © 2014. Published by Elsevier Inc.

  4. Novel virulent and broad-host-range Erwinia amylovora bacteriophages reveal a high degree of mosaicism and a relationship to Enterobacteriaceae phages.

    PubMed

    Born, Yannick; Fieseler, Lars; Marazzi, Janine; Lurz, Rudi; Duffy, Brion; Loessner, Martin J

    2011-09-01

    A diverse set of 24 novel phages infecting the fire blight pathogen Erwinia amylovora was isolated from fruit production environments in Switzerland. Based on initial screening, four phages (L1, M7, S6, and Y2) with broad host ranges were selected for detailed characterization and genome sequencing. Phage L1 is a member of the Podoviridae, with a 39.3-kbp genome featuring invariable genome ends with direct terminal repeats. Phage S6, another podovirus, was also found to possess direct terminal repeats but has a larger genome (74.7 kbp), and the virus particle exhibits a complex tail fiber structure. Phages M7 and Y2 both belong to the Myoviridae family and feature long, contractile tails and genomes of 84.7 kbp (M7) and 56.6 kbp (Y2), respectively, with direct terminal repeats. The architecture of all four phage genomes is typical for tailed phages, i.e., organized into function-specific gene clusters. All four phages completely lack genes or functions associated with lysogeny control, which correlates well with their broad host ranges and indicates strictly lytic (virulent) lifestyles without the possibility for host lysogenization. Comparative genomics revealed that M7 is similar to E. amylovora virus ΦEa21-4, whereas L1, S6, and Y2 are unrelated to any other E. amylovora phage. Instead, they feature similarities to enterobacterial viruses T7, N4, and ΦEcoM-GJ1. In a series of laboratory experiments, we provide proof of concept that specific two-phage cocktails offer the potential for biocontrol of the pathogen.

  5. γ-PGA Hydrolases of Phage Origin in Bacillus subtilis and Other Microbial Genomes.

    PubMed

    Mamberti, Stefania; Prati, Paola; Cremaschi, Paolo; Seppi, Claudio; Morelli, Carlo F; Galizzi, Alessandro; Fabbi, Massimo; Calvio, Cinzia

    2015-01-01

    Poly-γ-glutamate (γ-PGA) is an industrially interesting polymer secreted mainly by members of the class Bacilli which forms a shield able to protect bacteria from phagocytosis and phages. Few enzymes are known to degrade γ-PGA; among them is a phage-encoded γ-PGA hydrolase, PghP. The supposed role of PghP in phages is to ensure access to the surface of bacterial cells by dismantling the γ-PGA barrier. We identified four unannotated B. subtilis genes through similarity of their encoded products to PghP; in fact these genes reside in prophage elements of B. subtilis genome. The recombinant products of two of them demonstrate efficient polymer degradation, confirming that sequence similarity reflects functional homology. Genes encoding similar γ-PGA hydrolases were identified in phages specific for the order Bacillales and in numerous microbial genomes, not only belonging to that order. The distribution of the γ-PGA biosynthesis operon was also investigated with a bioinformatics approach; it was found that the list of organisms endowed with γ-PGA biosynthetic functions is larger than expected and includes several pathogenic species. Moreover in non-Bacillales bacteria the predicted γ-PGA hydrolase genes are preferentially found in species that do not have the genetic asset for polymer production. Our findings suggest that γ-PGA hydrolase genes might have spread across microbial genomes via horizontal exchanges rather than via phage infection. We hypothesize that, in natural habitats rich in γ-PGA supplied by producer organisms, the availability of hydrolases that release glutamate oligomers from γ-PGA might be a beneficial trait under positive selection.

  6. [Bioethics and abortion. Debate].

    PubMed

    Diniz, D; Gonzalez Velez, A C

    1998-06-01

    Although abortion has been the most debated of all issues analyzed in bioethics, no moral consensus has been achieved. The problem of abortion exemplifies the difficulty of establishing social dialogue in the face of distinct moral positions, and of creating an independent academic discussion based on writings that are passionately argumentative. The greatest difficulty posed by the abortion literature is to identify consistent philosophical and scientific arguments amid the rhetorical manipulation. A few illustrative texts were selected to characterize the contemporary debate. The terms used to describe abortion are full of moral meaning and must be analyzed for their underlying assumptions. Of the four main types of abortion, only 'eugenic abortion', as exemplified by the Nazis, does not consider the wishes of the woman or couple--a fundamental difference for most bioethicists. The terms 'selective abortion' and 'therapeutic abortion' are often confused, and selective abortion is often called eugenic abortion by opponents. The terms used to describe abortion practitioners, abortion opponents, and the 'product' are also of interest in determining the style of the article. The video entitled "The Silent Scream" was a classic example of violent and seductive rhetoric. Its type of discourse, freely mixing scientific arguments and moral beliefs, hinders analysis. Within writings about abortion three extreme positions may be identified: heteronomy (the belief that life is a gift that does not belong to one) versus reproductive autonomy; sanctity of life versus tangibility of life; and abortion as a crime versus abortion as morally neutral. Most individuals show an inconsistent array of beliefs, and few groups or individuals identify with the extreme positions. The principal argument of proponents of legalization is respect for the reproductive autonomy of the woman or couple based on the principle of individual liberty, while heteronomy is the main principle of

  7. Abortion Surveillance - United States, 2014.

    PubMed

    Jatlaoui, Tara C; Shah, Jill; Mandel, Michele G; Krashin, Jamie W; Suchdev, Danielle B; Jamieson, Denise J; Pazol, Karen

    2017-11-24

    Since 1969, CDC has conducted abortion surveillance to document the number and characteristics of women obtaining legal induced abortions in the United States. 2014. Each year, CDC requests abortion data from the central health agencies of 52 reporting areas (the 50 states, the District of Columbia, and New York City). The reporting areas provide this information voluntarily. For 2014, data were received from 49 reporting areas. For trend analysis, abortion data were evaluated from 48 areas that reported data every year during 2005-2014. Census and natality data, respectively, were used to calculate abortion rates (number of abortions per 1,000 women aged 15-44 years) and ratios (number of abortions per 1,000 live births). A total of 652,639 abortions were reported to CDC for 2014. Of these abortions, 98.4% were from the 48 reporting areas that provided data every year during 2005-2014. Among these 48 reporting areas, the abortion rate for 2014 was 12.1 abortions per 1,000 women aged 15-44 years, and the abortion ratio was 186 abortions per 1,000 live births. From 2013 to 2014, the total number and rate of reported abortions decreased 2%, and the ratio decreased 7%. From 2005 to 2014, the total number, rate, and ratio of reported abortions decreased 21%, 22%, and 21%, respectively. In 2014, all three measures reached their lowest level for the entire period of analysis (2005-2014). In 2014 and throughout the period of analysis, women in their 20s accounted for the majority of abortions and had the highest abortion rates; women in their 30s and older accounted for a much smaller percentage of abortions and had lower abortion rates. In 2014, women aged 20-24 and 25-29 years accounted for 32.2% and 26.7% of all reported abortions, respectively, and had abortion rates of 21.3 and 18.4 abortions per 1,000 women aged 20-24 and 25-29 years, respectively. In contrast, women aged 30-34, 35-39, and ≥40 years accounted for 17.1%, 9.7%, and 3.6% of all reported abortions

  8. A novel lineage of myoviruses infecting cyanobacteria is widespread in the oceans.

    PubMed

    Sabehi, Gazalah; Shaulov, Lihi; Silver, David H; Yanai, Itai; Harel, Amnon; Lindell, Debbie

    2012-02-07

    Viruses infecting bacteria (phages) are thought to greatly impact microbial population dynamics as well as the genome diversity and evolution of their hosts. Here we report on the discovery of a novel lineage of tailed dsDNA phages belonging to the family Myoviridae and describe its first representative, S-TIM5, that infects the ubiquitous marine cyanobacterium, Synechococcus. The genome of this phage encodes an entirely unique set of structural proteins not found in any currently known phage, indicating that it uses lineage-specific genes for virion morphogenesis and represents a previously unknown lineage of myoviruses. Furthermore, among its distinctive collection of replication and DNA metabolism genes, it carries a mitochondrial-like DNA polymerase gene, providing strong evidence for the bacteriophage origin of the mitochondrial DNA polymerase. S-TIM5 also encodes an array of bacterial-like metabolism genes commonly found in phages infecting cyanobacteria including photosynthesis, carbon metabolism and phosphorus acquisition genes. This suggests a common gene pool and gene swapping of cyanophage-specific genes among different phage lineages despite distinct sets of structural and replication genes. All cytosines following purine nucleotides are methylated in the S-TIM5 genome, constituting a unique methylation pattern that likely protects the genome from nuclease degradation. This phage is abundant in the Red Sea and S-TIM5 gene homologs are widespread in the oceans. This unusual phage type is thus likely to be an important player in the oceans, impacting the population dynamics and evolution of their primary producing cyanobacterial hosts.

  9. Application of a phage in decontaminating Vibrio parahaemolyticus in oysters.

    PubMed

    Zhang, Hui; Yang, Zhenquan; Zhou, Yan; Bao, Hongduo; Wang, Ran; Li, Tingwu; Pang, Maoda; Sun, Lichang; Zhou, Xiaohui

    2018-06-20

    Vibrio parahaemolyticus is a major pathogen that is mainly associated with seafood and is a global concern of food safety. With high prevalence of contamination in food, efficient strategy is needed to decontaminate those contaminated foods and control the emergence of vibriosis. In the present study, a V. parahaemolyticus-specific phage vB_VpaS_OMN (designated as phage OMN) was isolated from oyster. Phage OMN had good pH (5-9) and temperature tolerance (<50 °C). Phage OMN exhibited broad host range against isolates of V. parahaemolyticus (20/31). After treatment with phage OMN in the liquid condition for 7 h, the number of V. parahaemolyticus was reduced significantly compared to control treatment. When phage OMN was applied to oyster samples for 48 and 72 h, 90% and 99%, respectively, of V. parahaemolyticus was inactivated on Oyster meat surface. Sequence analysis showed that phage OMN had a 42.202 bp genome and revealed about 59.04% homology with Cronobacter phage vB_CsaP_Ss1. Only 10 CDSs can be predicted based on the GenBank database, while 42% of the CDSs were unique to OMN and had no known function, indicating that phage OMN is a new lytic phage. Fully understanding of the function for the phage genes and the properties of the phage is important for the development of strategies to control V. parahaemolyticus contamination in oysters and disease in aquaculture. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. The C lostridium difficile cell wall protein CwpV confers phase‐variable phage resistance

    PubMed Central

    Sekulovic, Ognjen; Ospina Bedoya, Maicol; Fivian‐Hughes, Amanda S.; Fairweather, Neil F.

    2015-01-01

    Summary Bacteriophages are present in virtually all ecosystems, and bacteria have developed multiple antiphage strategies to counter their attacks. C lostridium difficile is an important pathogen causing severe intestinal infections in humans and animals. Here we show that the conserved cell‐surface protein CwpV provides antiphage protection in C . difficile. This protein, for which the expression is phase‐variable, is classified into five types, each differing in their repeat‐containing C‐terminal domain. When expressed constitutively from a plasmid or the chromosome of locked ‘ON’ cells of C . difficile  R20291, CwpV conferred antiphage protection. Differences in the level of phage protection were observed depending on the phage morphological group, siphophages being the most sensitive with efficiency of plaquing (EOP) values of < 5 × 10−7 for phages ϕCD38‐2, ϕCD111 and ϕCD146. Protection against the myophages ϕMMP01 and ϕCD52 was weaker, with EOP values between 9.0 × 10−3 and 1.1 × 10−1. The C‐terminal domain of CwpV carries the antiphage activity and its deletion, or part of it, significantly reduced the antiphage protection. CwpV does not affect phage adsorption, but phage DNA replication is prevented, suggesting a mechanism reminiscent of superinfection exclusion systems normally encoded on prophages. CwpV thus represents a novel ubiquitous host‐encoded and phase‐variable antiphage system in C . difficile. PMID:26179020

  11. Abortion Before & After Roe

    PubMed Central

    Joyce, Ted; Tan, Ruoding; Zhang, Yuxiu

    2013-01-01

    We use unique data on abortions performed in New York State from 1971–1975 to demonstrate that women travelled hundreds of miles for a legal abortion before Roe. A100- mile increase in distance for women who live approximately 183 miles from New York was associated with a decline in abortion rates of 12.2 percent whereas the same change for women who lived 830 miles from New York lowered abortion rates by 3.3 percent. The abortion rates of nonwhites were more sensitive to distance than those of whites. We found a positive and robust association between distance to the nearest abortion provider and teen birth rates but less consistent estimates for other ages. Our results suggest that even if some states lost all abortion providers due to legislative policies, the impact on population measures of birth and abortion rates would be small as most women would travel to states with abortion services. PMID:23811233

  12. Identification of the cell binding domain in Nipah virus G glycoprotein using a phage display system.

    PubMed

    Lam, Chui-Wan; AbuBakar, Sazaly; Chang, Li-Yen

    2017-05-01

    Nipah virus (NiV) is a highly pathogenic zoonotic paramyxovirus with unusual broad host tropism and is designated as a Category C pathogen by the U.S. National Institute of Allergy and Infectious Diseases. NiV infection is initiated after binding of the viral G glycoprotein to the host cell receptor. The aim of this study was to map the NiV G glycoprotein cell binding domain using a phage display system. The NiV G extracellular domain was truncated and displayed as attachment proteins on M13 phage g3p minor coat protein. The binding efficiency of recombinant phages displaying different regions of NiV G to mammalian cells was evaluated. Results showed that regions of NiV G consisting of amino acids 396-602 (recombinant phage G4) and 498-602 (recombinant phage G5) demonstrated the highest binding to both Vero (5.5×10 3 cfu/ml and 5.6×10 3 cfu/ml) and THP-1 cells (3.5×10 3 cfu/ml and 2.9×10 3 cfu/ml). However, the binding of both of these recombinant phages to THP-1 cells was significantly lower than to Vero cells, and this could be due to the lack of primary host cell receptor expression on THP-1 cells. Furthermore, the binding between these two recombinant phages was competitive suggesting that there was a common host cell attachment site. This study employed an approach that is suitable for use in a biosafety level 2 containment laboratory without the need to use live virus to show that NiV G amino acids 498-602 play an important role for attachment to host cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. [Repeat induced abortion: A multicenter study on medical abortions in France in 2014].

    PubMed

    Opatowski, M; Bardy, F; David, P; Dunbavand, A; Saurel-Cubizolles, M-J

    2017-01-01

    To describe the social characteristics of women seeking a medical abortion, and the conditions of that abortion, according to whether they had one or more previous induced abortions. An observational study was carried out in 11 French units in 2013-2014, among women 18 years or older. A self-administered questionnaire on the abortion context and social situation was given to them, as well as a diary to record the pain level for each of five days following the mifepristone intake. The sample included 453 women. Among the respondents, 22% had had one previous abortion and 8% had had two or more. Women having had a previous voluntary abortion were more often isolated and in a poorer social situation than women having their first abortion. Better support for contraception after abortion could reduce the number of repeated abortions. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Evolving phage vectors for cell targeted gene delivery.

    PubMed

    Larocca, David; Burg, Michael A; Jensen-Pergakes, Kristen; Ravey, Edward Prenn; Gonzalez, Ana Maria; Baird, Andrew

    2002-03-01

    We adapted filamentous phage vectors for targeted gene delivery to mammalian cells by inserting a mammalian reporter gene expression cassette (GFP) into the vector backbone and fusing the pIII coat protein to a cell targeting ligand (i.e. FGF2, EGF). Like transfection with animal viral vectors, targeted phage gene delivery is concentration, time, and ligand dependent. Importantly, targeted phage particles are specific for the appropriate target cell surface receptor. Phage have distinct advantages over existing gene therapy vectors because they are simple, economical to produce at high titer, have no intrinsic tropism for mammalian cells, and are relatively simple to genetically modify and evolve. Initially transduction by targeted phage particles was low resulting in foreign gene expression in 1-2% of transfected cells. We increased transduction efficiency by modifying both the transfection protocol and vector design. For example, we stabilized the display of the targeting ligand to create multivalent phagemid-based vectors with transduction efficiencies of up to 45% in certain cell lines when combined with genotoxic treatment. Taken together, these studies establish that the efficiency of phage-mediated gene transfer can be significantly improved through genetic modification. We are currently evolving phage vectors with enhanced cell targeting, increased stability, reduced immunogenicity and other properties suitable for gene therapy.

  15. Post-abortion care: a women's health initiative to combat unsafe abortion.

    PubMed

    Greenslade, F C; Mckay, H; Wolf, M; Mclaurin, K

    1994-01-01

    Improving postabortion care can reduce the negative impact of unsafe abortion. Of the 53 million estimated induced abortions occurring annually about two out of five involve unsafe procedures. About one abortion occurs for every three births annually. 96% of abortions in Africa and 85% of abortions in Latin America are unsafe. About 100,000 to 200,000 women die every year from unsafe abortion, or 1 out of 400 women. Family planning is unavailable to over 120 million women in developing countries who desire contraception. Past moral and political controversies divert attention away from death and injury. The international community can take the opportunity to change affairs by adopting a women's health initiative globally. Improvements are needed in quality of care and accessibility of emergency treatment services. Emergency treatment services are usually only available at the tertiary level of care in urban areas. Poor transportation systems limit access. Access is also impaired by women's attitudes toward treatment centers. Availability of services needs to increased through decentralized centers. Clear protocols and comprehensive, systematic training must be accomplished in tandem with improvements in quality. Provision of technology such as manual vacuum aspiration is cost effective and an easy way to improve quality in primary care or outpatient settings. Unsafe abortion is a byproduct of the failure to provide adequate family planning for prevention of unwanted pregnancy. The obstacles, that interfere with provision of family planning to abortion users, should be removed. These obstacles include providers' lack of understanding of women's needs and motivations, separation between abortion and family planning services, misinformation about contraception following abortion, lack of acknowledgement about unsafe abortion, and women's low status. National and international policies also interfere with provision of contraception. Complete reproductive health care is

  16. Abortion surveillance - United States, 2006.

    PubMed

    Pazol, Karen; Gamble, Sonya B; Parker, Wilda Y; Cook, Douglas A; Zane, Suzanne B; Hamdan, Saeed

    2009-11-27

    Since 1969, CDC has conducted abortion surveillance to document the number and characteristics of women obtaining legal induced abortions in the United States. 2006. Each year, CDC requests abortion data from the central health agencies of 52 reporting areas (the 50 states, New York City, and the District of Columbia); these data are provided to CDC voluntarily. In 2006, data were received from 49 reporting areas. For the purpose of trend analysis, data were evaluated from the 46 areas that reported data every year during 1996-2006. For 2006, a total of 846,181 abortions were reported to CDC. Among the 46 areas that provided data consistently during 1996-2006, a total of 835,134 abortions (98.7% of the total) were reported; the abortion rate was 16.1 abortions per 1,000 women aged 15-44 years, and the abortion ratio was 236 abortions per 1,000 live births. During the previous decade (1997-2006), reported abortion numbers, rates, and ratios decreased 5.7%, 8.8%, and 14.8%, respectively; most of these declines occurred before 2001. During the previous year (2005-2006), the total number of abortions increased 3.1%, and the abortion rate increased 3.2%; the abortion ratio was stable. In 2006, as during the previous decade (1997-2006), women aged 20-29 years accounted for the majority (56.8%) of abortions and had the highest abortion rates (29.9 abortions per 1,000 women aged 20-24 years and 22.2 abortions per 1,000 women aged 25-29 years); by contrast, abortion ratios were highest at the extremes of reproductive age. Adolescents aged 15-19 years accounted for 16.5% of all abortions in 2006 and had an abortion rate of 14.8 abortions per 1,000 adolescents aged 15-19 years; women aged >or=35 years accounted for a smaller percentage (12.1%) of abortions and had lower abortion rates (7.8 abortions per 1,000 women aged 35-39 years and 2.6 abortions per 1,000 women aged >or=40 years). During 1997-2006, the percentage of abortions and the abortion rate increased among women

  17. Trends of abortion complications in a transition of abortion law revisions in Ethiopia.

    PubMed

    Gebrehiwot, Yirgu; Liabsuetrakul, Tippawan

    2009-03-01

    Evidence from developed countries has shown that abortion-related mortality and morbidity has decreased with the liberalization of the abortion law. This study aimed to assess the trend of hospital-based abortion complications during the transition of legalization in Ethiopia in May 2005. Medical records of women with abortion complications from 2003 to 2007 were reviewed (n = 773). Abortion and its complications with regard to legalization were described by rates and ratios, and predictors of fatal outcomes were analyzed by logistic regression. The overall and abortion-related maternal mortality ratios (AMMRs) showed a non-statistically significant downward trend over the 5-year period. However, the case fatality rate of abortion increased from 1.1% in 2003 to 3.6% in 2007. Late gestational age, history of interference and presenting after new abortion legislation passed have been found to be significant predictors of mortality. Decreased trends of abortion ratio and the AMMR were identified, but the severity of abortion complications and the case fatality rate increased during the transition of legal revision.

  18. APPEARANCE OF NEW PHAGE TYPES AND NEW LYSOGENIC STRAINS AFTER ADAPTATION OF LYSOGENIC B. MEGATHERIUM TO AMMONIUM SULFATE CULTURE MEDIUM

    PubMed Central

    Northrop, John H.; Murphy, James S.

    1956-01-01

    1. Lysogenic B. megatherium 899a was adapted to growth in a minimal ammonium sulfate medium (ASCM). 2. Adaptation took place slowly and the following changes in the culture occurred: (a) The growth rate increased from 0.5 to 1.5–2.0/hr. (b) The culture changed from diffuse to mucoid. (c) The total phage titer, and the gelatinase concentration decreased to 1/100 or less. (d) The types of phage produced changed from >99 per cent T (wild type) to 30 to 60 per cent miscellaneous clear types. The original T phage was replaced by a different smaller t, never observed in the original 899a culture. (e) Several new colony types also appeared, but the colony morphology was not correlated with the phage types produced. None of the colony types was stable on repeated transfer either in peptone or ASCM, but continued to disassociate into different colony types (cf. Ivánovics, 1955). 3. Control experiments showed that these changes in phage production and colony types could not be brought about by growing sensitive B. megatherium in the presence of the various new phages, in ASCM. It is therefore unlikely that the changes observed in adapted culture were due to infection of a sensitive cell with phage. 4. Continued growth of the ASCM-adapted strain in peptone resulted in increasing the total phage titer, and also the gelatinase concentration. The growth rate returned to its original value and the ability to grow rapidly in ASCM was soon lost. The phage types, however, remained the same as in the ASCM. 5. An improved cell for steady state growth is described. PMID:13295557

  19. Abortion surveillance--United States, 2009.

    PubMed

    Pazol, Karen; Creanga, Andreea A; Zane, Suzanne B; Burley, Kim D; Jamieson, Denise J

    2012-11-23

    Since 1969, CDC has conducted abortion surveillance to document the number and characteristics of women obtaining legal induced abortions in the United States. 2009. Each year, CDC requests abortion data from the central health agencies of 52 reporting areas (the 50 states, the District of Columbia, and New York City). The reporting areas provide this information voluntarily. For 2009, data were received from 48 reporting areas. For the purpose of trend analysis, abortion data were evaluated from the 45 areas that reported data every year during 2000-2009. Census and natality data, respectively, were used to calculated abortion rates (number of abortions per 1,000 women) and ratios (number of abortions per 1,000 live births). A total of 784,507 abortions were reported to CDC for 2009. Of these abortions, 772,630 (98.5%) were from the 45 reporting areas that provided data every year during 2000-2009. Among these same 45 reporting areas, the abortion rate for 2009 was 15.1 abortions per 1,000 women aged 15-44 years, and the abortion ratio was 227 abortions per 1,000 live births. Compared with 2008, the total number and rate of reported abortions for 2009 decreased 5%, representing the largest single year decrease for the entire period of analysis. The abortion ratio decreased 2%. From 2000 to 2009, the total number, rate, and ratio of reported abortions decreased 6%, 7%, and 8%, respectively, to the lowest levels for 2000-2009. In 2009 and throughout the period of analysis, women in their 20s accounted for the majority of abortions and had the highest abortion rates, whereas women aged ≥30 years accounted for a much smaller percentage of abortions and had lower abortion rates. In 2009, women aged 20-24 and 25-29 years accounted for 32.7% and 24.4% of all abortions, respectively, and had an abortion rate of 27.4 abortions per 1,000 women aged 20-24 years and 20.4 abortions per 1,000 women aged 25-29 years. In contrast, women aged 30-34, 35-39, and ≥40 years

  20. Abortion Surveillance - United States, 2013.

    PubMed

    Jatlaoui, Tara C; Ewing, Alexander; Mandel, Michele G; Simmons, Katharine B; Suchdev, Danielle B; Jamieson, Denise J; Pazol, Karen

    2016-11-25

    Since 1969, CDC has conducted abortion surveillance to document the number and characteristics of women obtaining legal induced abortions in the United States. 2013. Each year, CDC requests abortion data from the central health agencies of 52 reporting areas (the 50 states, the District of Columbia, and New York City). The reporting areas provide this information voluntarily. For 2013, data were received from 49 reporting areas. For trend analysis, abortion data were evaluated from 47 areas that reported data every year during 2004-2013. Census and natality data, respectively, were used to calculate abortion rates (number of abortions per 1,000 women) and ratios (number of abortions per 1,000 live births). A total of 664,435 abortions were reported to CDC for 2013. Of these abortions, 98.2% were from the 47 reporting areas that provided data every year during 2004-2013. Among these 47 reporting areas, the abortion rate for 2013 was 12.5 abortions per 1,000 women aged 15-44 years, and the abortion ratio was 200 abortions per 1,000 live births. From 2012 to 2013, the total number, rate, and ratio of reported abortions decreased 5%. From 2004 to 2013, the total number, rate, and ratio of reported abortions decreased 20%, 21%, and 17%, respectively. In 2013, all three measures reached their lowest level for the entire period of analysis (2004-2013). In 2013 and throughout the period of analysis, women in their 20s accounted for the majority of abortions and had the highest abortion rates; women in their 30s and older accounted for a much smaller percentage of abortions and had lower abortion rates. In 2013, women aged 20-24 and 25-29 years accounted for 32.7% and 25.9% of all abortions, respectively, and had abortion rates of 21.8 and 18.2 abortions per 1,000 women aged 20-24 and 25-29 years, respectively. In contrast, women aged 30-34, 35-39, and ≥40 years accounted for 16.8%, 9.2%, and 3.6% of all abortions, respectively, and had abortion rates of 11.8, 7.0, and 2