We describe a simple colony overlay procedure for peptidases (COPP) for the rapid fluorogenic detection and quantification of Vibrionaceae from seawater, shellfish, sewage, and clinical samples. The assay detects phosphoglucose isomerase with a lysyl aminopeptidase activity that is produced by Vibrionaceae family members. Overnight cultures are overlaid for 10 min with membranes containing a synthetic substrate, and the membranes are examined for fluorescent foci under UV illumination. Fluorescent foci were produced by all the Vibrionaceae tested, including Vibrio spp., Aeromonas spp., and Plesiomonas spp. Fluorescence was not produced by non-Vibrionaceae pathogens. Vibrio cholerae strains O1, O139, O22, and O155 were strongly positive. Seawater and oysters were assayed, and 87 of 93 (93.5%) of the positive isolates were identified biochemically as Vibrionaceae, principally Vibrio vulnificus, Vibrio parahaemolyticus, Aeromonas hydrophila, Photobacterium damselae, and Shewanella putrefaciens. None of 50 nonfluorescent isolates were Vibrionaceae. No Vibrionaceae were detected in soil, and only A. hydrophila was detected in sewage. The COPP technique may be particularly valuable in environmental and food-testing laboratories and for monitoring water quality in the aquaculture industry.
Richards, Gary P.; Watson, Michael A.; Parveen, Salina
We describe a simple colony overlay procedure for peptidases (COPP) for the rapid fluorogenic detection and quantification of Vibrionaceae from seawater, shellfish, sewage, and clinical samples. The assay detects phosphoglucose isomerase with a lysyl aminopeptidase activity that is produced by Vibrionaceae family members. Overnight cultures are overlaid for 10 min with membranes containing a synthetic substrate, and the membranes are examined for fluorescent foci under UV illumination. Fluorescent foci were produced by all the Vibrionaceae tested, including Vibrio spp., Aeromonas spp., and Plesiomonas spp. Fluorescence was not produced by non-Vibrionaceae pathogens. Vibrio cholerae strains O1, O139, O22, and O155 were strongly positive. Seawater and oysters were assayed, and 87 of 93 (93.5%) of the positive isolates were identified biochemically as Vibrionaceae, principally Vibrio vulnificus, Vibrio parahaemolyticus, Aeromonas hydrophila, Photobacterium damselae, and Shewanella putrefaciens. None of 50 nonfluorescent isolates were Vibrionaceae. No Vibrionaceae were detected in soil, and only A. hydrophila was detected in sewage. The COPP technique may be particularly valuable in environmental and food-testing laboratories and for monitoring water quality in the aquaculture industry. PMID:16000757
Richards, Gary P; Watson, Michael A; Parveen, Salina
Use of inadequate methods for classification of bacteria in the so-called Harveyi clade (family Vibrionaceae, Gammaproteobacteria) has led to incorrect assignment of strains and proliferation of synonymous species. In order to resolve taxonomic ambiguities within the Harveyi clade and to test usefulness of whole genome sequence data for classification of Vibrionaceae, draft genome sequences of 12 strains were determined and analysed. The sequencing included type strains of seven species: Vibrio sagamiensis NBRC 104589(T), Vibrio azureus NBRC 104587(T), Vibrio harveyi NBRC 15634(T), Vibrio rotiferianus LMG 21460(T), Vibrio campbellii NBRC 15631(T), Vibrio jasicida LMG 25398(T), and Vibrio owensii LMG 25443(T). Draft genome sequences of strain LMG 25430, previously designated the type strain of [Vibrio communis], and two strains (MWB 21 and 090810c) from the 'beijerinckii' lineage were also determined. Whole genomes of two additional strains (ATCC 25919 and 200612B) that previously could not be assigned to any Harveyi clade species were also sequenced. Analysis of the genome sequence data revealed a clear case of synonymy between V. owensii and [V. communis], confirming an earlier proposal to synonymize both species. Both strains from the 'beijerinckii' lineage were classified as V. jasicida, while the strains ATCC 25919 and 200612B were classified as V. owensii and V. campbellii, respectively. We also found that two strains, AND4 and Ex25, are closely related to Harveyi clade bacteria, but could not be assigned to any species of the family Vibrionaceae. The use of whole genome sequence data for the taxonomic classification of the Harveyi clade bacteria and other members of the family Vibrionaceae is also discussed. PMID:23710045
Urbanczyk, Henryk; Ogura, Yoshitoshi; Hayashi, Tetsuya
It is shown that strains of Vibrio cholerae of serovar O1, biovar eltor, subtype Ogawa, museum strains V. cholerae of serovar O1 and NAG-vibrios (isolated from various sources: sea, river and sewage water, canal water and people) possess identical composition of cell fatty acids with prevailing hexadecenoic, hexadecanoic and octadecenoic acids. Being identical, fatty acid profiles of V. parahaemolyticus and V. alginolyticus, are close to that of V. cholerae differing from the latter mainly by the higher content of dodecanoic acid. Similarity of Aeromonas sp. and Vibrio strains in the fatty acid composition proves phylogenetic relation-ship of these bacteria. Fatty acid composition of Plesiomonas shigelloides cells characterized by the presence of methylenhexadecanoic acid as well as by similarity with Vibrio and Aeromonas by the content of most fatty acids confirms a supposition of R. R. Colwell on the intermediate status of genus Plesiomonas between the families Enterobacteriaceae and Vibrionaceae. Independent of the growth medium, the strains Vibrio. Aeromonas and Plesiomonas preserved a fatty-acid profile, inherent in them, with variations mainly in the content of fatty acids with the odd number of carbon atoms. Allowing for relative stability of fatty acid composition and its peculiarity in certain taxonomic groups of the studied bacteria, the above test may be used as additional objective criterion to identify the representatives of Vibrionaceae family. PMID:9044701
Vasiurenko, Z P; Padchenko, A G; Ruban, N M; Alekseenko, V V; Dobroshtan, E V; Gurleva, G G; Opanasenko, I S
Three assays were developed to enumerate total and fecal Escherichia coli and total Vibrionaceae in shellfish, seawater, and other foods and environmental samples. Assays involve membrane overlays of overnight colonies on nonselective agar plates to detect ?-glucuronidase and lysyl aminopeptidase activities for E. coli and Vibrionaceae, respectively. Cellulose membranes containing the substrates 4-methylumbeferyl-?-D-glucuronide (MUG) produced a bright blue fluorescence when overlaid onto E. coli, while L-lysyl-7-amino-4-trifluoromethylcoumarin produced green fluorescent foci when overlaid onto Vibrionaceae family members. A multiplex assay was also developed for simultaneously enumerating total E. coli and total Vibrionaceae in oysters and seawater. Overall, 65% of overlaid E. coli (non-O157:H7) were MUG-positive, compared with 62% as determined by the most-probable-number-MUG assay. The overlays are rapid, simple, and cost effective for quantification purposes. This research provides practical alternatives for monitoring bacterial indicators and potential pathogens in complex samples, including molluscan shellfish.
Richards, Gary P.; Watson, Michael A.
Six commercially available bacterial identification products were tested with Vibrio alginolyticus (12 strains), V. cholerae (30 strains), Photobacterium (Vibrio) damselae (10 strains), V. fluvialis (10 strains), V. furnissii (4 strains), V. hollisae (10 strains), V. metschnikovii (9 strains), V. mimicus (10 strains), V. parahaemolyticus (30 strains), and V. vulnificus (10 strains) to determine the accuracy of each system for identification. The products included API 20E, Crystal E/NF, MicroScan Neg ID2 and Rapid Neg ID3, and Vitek GNI+ and ID-GNB. Each product was tested only with those species that were listed in its database. Overall, the systems correctly identified 63.9, 80.9, 63.1, 73.6, 73.5, and 77.7% of the isolates to species level, respectively. Error rates ranged from 0.8% for the API 20E to 10.4% for the Rapid Neg ID3. The API 20E gave “no identification” for 13.1% of the isolates, while the Neg ID2, GNI+, ID-GNB, and Crystal were unable to identify 1.8, 2.9, 5.0, and 6.9%, respectively. For V. cholerae, specifically, accuracy ranged from 50.0 to 96.7%, with the API 20E having the worst performance and Crystal having the best. V. fluvialis presented the biggest challenge for the API 20E and the GNI+, with probabilities averaging 10%, while V. mimicus was a major problem with the Crystal E/NF, which identified none of the strains correctly. With the Neg ID2, correct answers were often obtained only after a modified inoculation of the panel with a bacterial suspension prepared with 0.85% NaCl. Additional tests required for identification often included growth in the absence of NaCl, which is not readily available in most clinical laboratories. The only product to correctly identify at least 90% of V. cholerae strains was the Crystal E/NF, and only three of the six products, the API 20E and both of the Vitek cards, correctly identified more than 90% of the V. parahaemolyticus strains. Thus, extreme care must be taken in the interpretation of answers from these six commercially available systems for the identification of Vibrio species.
O'Hara, Caroline M.; Sowers, Evangeline G.; Bopp, Cheryl A.; Duda, Sarah B.; Strockbine, Nancy A.
Six commercially available bacterial identification products were tested with Vibrio alginolyticus (12 strains), V. cholerae (30 strains), Photobacterium (Vibrio) damselae (10 strains), V. fluvialis (10 strains), V. furnissii (4 strains), V. hollisae (10 strains), V. metschnikovii (9 strains), V. mimicus (10 strains), V. parahaemolyticus (30 strains), and V. vulnificus (10 strains) to determine the accuracy of each system for identification. The products included API 20E, Crystal E/NF, MicroScan Neg ID2 and Rapid Neg ID3, and Vitek GNI+ and ID-GNB. Each product was tested only with those species that were listed in its database. Overall, the systems correctly identified 63.9, 80.9, 63.1, 73.6, 73.5, and 77.7% of the isolates to species level, respectively. Error rates ranged from 0.8% for the API 20E to 10.4% for the Rapid Neg ID3. The API 20E gave "no identification" for 13.1% of the isolates, while the Neg ID2, GNI+, ID-GNB, and Crystal were unable to identify 1.8, 2.9, 5.0, and 6.9%, respectively. For V. cholerae, specifically, accuracy ranged from 50.0 to 96.7%, with the API 20E having the worst performance and Crystal having the best. V. fluvialis presented the biggest challenge for the API 20E and the GNI+, with probabilities averaging 10%, while V. mimicus was a major problem with the Crystal E/NF, which identified none of the strains correctly. With the Neg ID2, correct answers were often obtained only after a modified inoculation of the panel with a bacterial suspension prepared with 0.85% NaCl. Additional tests required for identification often included growth in the absence of NaCl, which is not readily available in most clinical laboratories. The only product to correctly identify at least 90% of V. cholerae strains was the Crystal E/NF, and only three of the six products, the API 20E and both of the Vitek cards, correctly identified more than 90% of the V. parahaemolyticus strains. Thus, extreme care must be taken in the interpretation of answers from these six commercially available systems for the identification of Vibrio species. PMID:14662957
O'Hara, Caroline M; Sowers, Evangeline G; Bopp, Cheryl A; Duda, Sarah B; Strockbine, Nancy A
Three assays were developed to enumerate total and fecal Escherichia coli and total Vibrionaceae in shellfish, seawater, and other foods and environmental samples. Assays involve membrane overlays of overnight colonies on nonselective agar plates to detect beta-glucuronidase and lysyl aminopeptidase activities for E. coli and Vibrionaceae, respectively. Cellulose membranes containing the substrates 4-methylumbeferyl-beta-D-glucuronide (MUG) produced a bright blue fluorescence when overlaid onto E. coli, while L-lysyl-7-amino-4-trifluoromethylcoumarin produced green fluorescent foci when overlaid onto Vibrionaceae family members. A multiplex assay was also developed for simultaneously enumerating total E. coli and total Vibrionaceae in oysters and seawater. Overall, 65% of overlaid E. coli (non-O157:H7) were MUG-positive, compared with 62% as determined by the most-probable-number-MUG assay. The overlays are rapid, simple, and cost effective for quantification purposes. This research provides practical alternatives for monitoring bacterial indicators and potential pathogens in complex samples, including molluscan shellfish. PMID:20396663
Richards, Gary P; Watson, Michael A
Oyster gardening is a practice designed to restore habitat for marine life and to improve water quality. This study determined physical and chemical water-quality parameters at two oyster gardening sites in the Delaware Inland Bays and compared them with total aerobic bacteria and Vibrionaceae concentrations in Eastern oysters (Crassostrea virginica). One site was located at the end of a man-made canal, whereas the other was located in an open bay. Measured water parameters included temperature, dissolved oxygen (DO), salinity, pH, total nitrogen, nitrate, nitrite, total phosphorus, and total suspended solids. The highest Vibrionaceae levels, as determined by the colony overlay procedure for peptidases, were at the canal site in September (3.5 × 10(5) g(-1)) and at the bay site in August (1.9 × 10(5) g(-1)). Vibrionaceae levels were significantly greater during the duration of the study at the canal site (P = 0.01). This study provides the first baseline levels for total Vibrionaceae in the Delaware Inland Bays. Minimum DO readings at the bay and canal sites were 3.0 and 2.3 mg l(-1), respectively, far less than the state-targeted minimum threshold of 5.0 mg l(-1). Total phosphorus levels exceeded recommendations of ?0.1 mg l(-1) at the bay and canal sites for all monthly samplings, with mean monthly highs at both sites ?0.68 mg l(-1) in August. Nitrogen occasionally exceeded the recommended level of 1.0 mg l(-1) at both sites. Overall, waters were highly degraded from high phosphates, nitrogen, and total suspended solids as well as low DO. PMID:22183874
Fay, Johnna P; Richards, Gary P; Ozbay, Gulnihal
In bacteria, the discovery of noncoding small RNAs (sRNAs) as modulators of gene expression in response to environmental signals has brought new insights into bacterial gene regulation, including control of pathogenicity. The Vibrionaceae constitute a family of marine bacteria of which many are responsible for infections affecting not only humans, such as Vibrio cholerae but also fish and marine invertebrates, representing the major cause of mortality in farmed marine species. They are able to colonize many habitats, existing as planktonic forms, in biofilms or associated with various hosts. This high adaptability is linked to their capacity to generate genetic diversity, in part through lateral gene transfer, but also by varying gene expression control. In the recent years, several major studies have illustrated the importance of small regulatory sRNAs in the Vibrionaceae for the control of pathogenicity and adaptation to environment and nutrient sources such as chitin, especially in V. cholerae and Vibrio harveyi. The existence of a complex regulatory network controlled by quorum sensing has been demonstrated in which sRNAs play central roles. This review covers major advances made in the discovery and elucidation of functions of Vibrionaceae sRNAs within the last 10?years. PMID:24458378
Nguyen, An Ngoc; Jacq, Annick
Bacteria belonging to the Vibrionaceae family are widespread in the marine environment. Today, 128 species of vibrios are known. Several of them are infamous for their pathogenicity or symbiotic relationships. Despite their ability to interact with eukaryotes, the vibrios are greatly underexplored for their ability to produce bioactive secondary metabolites and studies have been limited to only a few species. Most of the compounds isolated from vibrios so far are non-ribosomal peptides or hybrids thereof, with examples of N-containing compounds produced independent of nonribosomal peptide synthetases (NRPS). Though covering a limited chemical space, vibrios produce compounds with attractive biological activities, including antibacterial, anticancer, and antivirulence activities. This review highlights some of the most interesting structures from this group of bacteria. Many compounds found in vibrios have also been isolated from other distantly related bacteria. This cosmopolitan occurrence of metabolites indicates a high incidence of horizontal gene transfer, which raises interesting questions concerning the ecological function of some of these molecules. This account underlines the pending potential for exploring new bacterial sources of bioactive compounds and the challenges related to their investigation.
Mansson, Maria; Gram, Lone; Larsen, Thomas O.
Phosphoglucose isomerase (PGI) with a novel lysyl aminopeptidase (LysAP) activity was recently purified and characterized from Vibrio vulnificus. We showed that it cleaves the amino-terminal lysyl residue from des-Arg(10)-kallidin to produce des-Arg(9)-bradykinin, suggesting that it plays a role in virulence. A survey was conducted to determine the presence of this potential virulence-enhancing enzyme among twenty-three halotolerant human and fish pathogens from eleven species within the Vibrionaceae family, including V. vulnificus, V. parahaemolyticus, V. cholerae, Aeromonas hydrophila, and Plesiomonas shigelloides. In addition, fourteen species of non-Vibrionaceae pathogens were screened for LysAP activity. Cell lysates were partially purified by anion exchange chromatography and fractions were screened for LysAP and isomerase activities. PGI-LysAP activity was detected in chromatographic fractions from all the Vibrio species tested, but was not detected in any of the non-Vibrionaceae pathogens. Levels of isomerase and LysAP activity correlated (R(2)=0.92) for nine strains of V. vulnificus. Since the Vibrionaceae represent an important family of human and fish pathogens, our identification of PGI-LysAP activity in a broad array of vibrios may lead to the development of improved analytical methods for their identification as well as interventions to reduce the high morbidity and mortality associated with some Vibrionaceae infections in clinical, veterinary, and aquaculture settings. PMID:15752701
Richards, Gary P; Parveen, Salina
Background Phylogenetic hypotheses based on complete genome data are presented for the Gammaproteobacteria family Vibrionaceae. Two taxon samplings are presented: one including all those taxa for which the genome sequences are complete in terms of arrangement (chromosomal location of fragments; 19 taxa) and one for which the genome sequences contain multiple contigs (44 taxa). Analyses are presented under the Maximum Parsimony and Maximum Likelihood optimality criteria for total evidence datasets, the two chromosomes separately, and individual analyses of locally collinear blocks. Three of the genomes included in the 44 taxon dataset, those of Vibrio gazogenes, Salinivibrio costicola, and Aliivibrio logei have been newly sequenced and their genome sequences are documented here. Results Phylogenetic results for the 19-taxon datasets show similar levels of collinear subset of dataset incongruence as a previous study of 22 taxa from the sister family Shewanellaceae, while also echoing the strong phylogenetic performance of random subsets of data also shown in this study. Phylogenetic results for both the 19-taxon and 44-taxon datasets corroborate previous hypotheses about the placement of Photobacterium and Aliivibrio within Vibrionaceae and also highlight problems with how Photobacterium is delimited and indicate that it likely should be dissolved into Vibrio to produce a phylogenetic taxonomy. The 19-taxon and 44-taxon trees based on the large chromosome are congruent for the majority of taxa that are present in both datasets. Analyses of the 44-taxon sampling based on the second, small chromosome are quite different from those based on the large chromosome, which is not surprising given the dramatically divergent nature of the small chromosome and the difficulty in postulating primary homologies. Conclusions The phylogenetic analyses presented here represent the most comprehensive genome-level phylogenetic analyses in terms of taxa and data. Based on the availability of genome data for many bacterial species on GenBank, many other bacterial groups would also be amenable to similar genome-scale phylogenetic analyses even when present in multiple contigs. The result that collinear subsets of data are incongruent with the concatenated dataset and with each other while random data subsets show very little incongruence echoes the result of previous work on Shewanellaceae. The 44-taxon phylogenetic analysis presented here thus represents the future of phylogenomic analyses in scope and complexity.
The Phoenix 100 ID/AST system (Becton Dickinson Co., Sparks, Md.) is an automated system for the identification and antimicrobial susceptibility testing of bacterial isolates. This system with its negative identification (NID) panel was evaluated for its accuracy in the identification of 507 isolates of the family Enterobacteriaceae, 57 other nonenteric gram-negative isolates that are commonly isolated in clinical microbiology laboratories, and 138 isolates of the family Vibrionaceae. All of the isolates had been characterized by using approximately 48 conventional tube biochemicals. Of the 507 isolates of the Enterobacteriaceae, 456 (89.9%) were correctly identified to the genus and species levels. The five isolates of Proteus penneri required an off-line indole test, as suggested by the system to differentiate them from Proteus vulgaris. The identifications of 20 (3.9%) isolates were correct to the genus level but incorrect at the species level. Two (0.4%) isolates were reported as “no identification.” Misidentifications to the genus and species levels occurred for 29 (5.7%) isolates of the Enterobacteriaceae. These incorrect identifications were spread over 14 different genera. The most common error was the misidentification of Salmonella species. The shortest time for a correct identification was 2 h 8 min. The longest time was 12 h 27 min, for the identification of a Serratia marcescens isolate. Of the 57 isolates of nonenteric gram-negative bacilli (Acinetobacter, Aeromonas, Burkholderia, Plesiomonas, Pseudomonas, and Stenotrophomonas spp.), 48 (84.2%) were correctly identified to the genus and species levels and 7 (12.3%) were correctly identified to the genus level but not to the species level. The average time for a correct identification was 5 h 11 min. Of the Vibrionaceae spp., 123 (89.1%) were correctly identified at the end of the initial incubation period, which averaged 4 h. Based on the findings of this study, the Phoenix 100 ID/AST system NID panel falls short of being an acceptable new method for the identification of the Enterobacteriaceae, Vibrionaceae, and gram-negative nonenteric isolates that are commonly encountered in many hospital microbiology laboratories.
O'Hara, Caroline M.
Holins are small "hole-forming" transmembrane proteins that mediate bacterial cell lysis during programmed cell death or following phage infection. We have identified fifty two families of established or putative holins and have included representative members of these proteins in the Transporter Classification Database (TCDB; www.tcdb.org). We have identified the organismal sources of members of these families, calculated their average protein sizes, estimated their topologies and determined their relative family sizes. Topological analyses suggest that these proteins can have 1, 2, 3 or 4 transmembrane ?-helical segments (TMSs), and members of a single family are frequently, but not always, of a single topology. In one case, proteins of a family proved to have either 2 or 4 TMSs, and the latter arose by intragenic duplication of a primordial 2 TMS protein-encoding gene resembling the former. Using established statistical approaches, some of these families have been shown to be related by common descent. Seven superfamilies, including 21 of the 52 recognized families were identified. Conserved motif and Pfam analyses confirmed most superfamily assignments. These results serve to expand upon the scope of channel-forming bacterial holins. PMID:23856191
Reddy, Bhaskara L; Saier, Milton H
Cytoskeletal proteins are important mediators of cellular organization in both eukaryotes and bacteria. In the past, cytoskeletal studies have largely focused on three major cytoskeletal families, namely the eukaryotic actin, tubulin, and intermediate filament (IF) proteins and their bacterial homologs MreB, FtsZ, and crescentin. However, mounting evidence suggests that these proteins represent only the tip of the iceberg, as the cellular cytoskeletal network is far more complex. In bacteria, each of MreB, FtsZ, and crescentin represents only one member of large families of diverse homologs. There are also newly identified bacterial cytoskeletal proteins with no eukaryotic homologs, such as WACA proteins and bactofilins. Furthermore, there are universally conserved proteins, such as the metabolic enzyme CtpS, that assemble into filamentous structures that can be repurposed for structural cytoskeletal functions. Recent studies have also identified an increasing number of eukaryotic cytoskeletal proteins that are unrelated to actin, tubulin, and IFs, such that expanding our understanding of cytoskeletal proteins is advancing the understanding of the cell biology of all organisms. Here, we summarize the recent explosion in the identification of new members of the bacterial cytoskeleton and describe a hypothesis for the evolution of the cytoskeleton from self-assembling enzymes.
Ingerson-Mahar, Michael; Gitai, Zemer
How reproducibly microbial populations assemble in the wild remains poorly understood. Here, we assess evidence for ecological specialization and predictability of fine-scale population structure and habitat association in coastal ocean Vibrionaceae across years. We compare Vibrionaceae lifestyles in the bacterioplankton (combinations of free-living, particle, or zooplankton associations) measured using the same sampling scheme in 2006 and 2009 to assess whether the same groups show the same environmental association year after year. This reveals complex dynamics with populations falling primarily into two categories: (i) nearly equally represented in each of the two samplings and (ii) highly skewed, often to an extent that they appear exclusive to one or the other sampling times. Importantly, populations recovered at the same abundance in both samplings occupied highly similar habitats suggesting predictable and robust environmental association while skewed abundances of some populations may be triggered by shifts in ecological conditions. The latter is supported by difference in the composition of large eukaryotic plankton between years, with samples in 2006 being dominated by copepods, and those in 2009 by diatoms. Overall, the comparison supports highly predictable population-habitat linkage but highlights the fact that complex, and often unmeasured, environmental dynamics in habitat occurrence may have strong effects on population dynamics.
Szabo, Gitta; Preheim, Sarah P; Kauffman, Kathryn M; David, Lawrence A; Shapiro, Jesse; Alm, Eric J; Polz, Martin F
Loliginid and sepiolid squid light organs are known to host a variety of bacterial species from the family Vibrionaceae, yet little is known about the species diversity and characteristics among different host squids. Here we present a broad-ranging molecular and physiological analysis of the bacteria colonizing light organs in loliginid and sepiolid squids from various field locations of the Indo-West Pacific (Australia and Thailand). Our PCR-RFLP analysis, physiological characterization, carbon utilization profiling, and electron microscopy data indicate that loliginid squid in the Indo-West Pacific carry a consortium of bacterial species from the families Vibrionaceae and Photobacteriaceae. This research also confirms our previous report of the presence of Vibrio harveyi as a member of the bacterial population colonizing light organs in loliginid squid. pyrH sequence data were used to confirm isolate identity, and indicates that Vibrio and Photobacterium comprise most of the light organ colonizers of squids from Australia, confirming previous reports for Australian loliginid and sepiolid squids. In addition, combined phylogenetic analysis of PCR-RFLP and 16S rDNA data from Australian and Thai isolates associated both Photobacterium and Vibrio clades with both loliginid and sepiolid strains, providing support that geographical origin does not correlate with their relatedness. These results indicate that both loliginid and sepiolid squids demonstrate symbiont specificity (Vibrionaceae), but their distribution is more likely due to environmental factors that are present during the infection process. This study adds significantly to the growing evidence for complex and dynamic associations in nature and highlights the importance of exploring symbiotic relationships in which non-virulent strains of pathogenic Vibrio species could establish associations with marine invertebrates.
Guerrero-Ferreira, Ricardo; Gorman, Clayton; Chavez, Alba A.; Willie, Shantell
The Vibrionaceae is comprised of numerous aquatic species and includes several human pathogens, such as Vibrio cholerae, the cause of cholera. All organisms in this family have two chromosomes, and replication of the smaller one depends on rctB, a gene that is restricted to the Vibrionaceae. Given the increasing prevalence of multi-drug resistance in pathogenic vibrios, there is a need for new targets and drugs to combat these pathogens. Here, we carried out a high throughput cell-based screen to find small molecule inhibitors of RctB. We identified a compound that blocked growth of an E. coli strain bearing an rctB-dependent plasmid but did not influence growth of E. coli lacking this plasmid. This compound, designated vibrepin, had potent cidal activity against V. cholerae and inhibited the growth of all vibrio species tested. Vibrepin blocked RctB oriCII unwinding, apparently by promoting formation of large non-functional RctB complexes. Although vibrepin also appears to have targets other than RctB, our findings suggest that RctB is an attractive target for generation of novel antibiotics that only block growth of vibrios. Vibrio-specific agents, unlike antibiotics currently used in clinical practice, will not engender resistance in the normal human flora or in non-vibrio environmental microorganisms.
Yamaichi, Yoshiharu; Duigou, Stephane; Shakhnovich, Elizabeth A.; Waldor, Matthew K.
Pathogenic bacteria utilize a variety of virulence factors that contribute to the clinical manifestation of their pathogenesis. Bacterial ADP-ribosylating exotoxins (bAREs) represent one family of virulence factors that exert their toxic effects by transferring the ADP-ribose moiety of NAD onto specific eucaryotic target proteins. The observations that some bAREs ADP-ribosylate eucaryotic proteins that regulate signal transduction, like the heterotrimeric GTP-binding proteins and the low-molecular-weight GTP-binding proteins, has extended interest in bAREs beyond the bacteriology laboratory. Molecular studies have shown that bAREs possess little primary amino acid homology and have diverse quaternary structure-function organization. Underlying this apparent diversity, biochemical and crystallographic studies have shown that several bAREs have conserved active-site structures and possess a conserved glutamic acid within their active sites.
Krueger, K M; Barbieri, J T
Horizontal gene transfer (HGT) is thought to occur frequently in bacteria in nature and to play an important role in bacterial evolution, contributing to the formation of new species. To gain insight into the frequency of HGT in Vibrionaceae and its possible impact on speciation, we assessed the incidence of interspecies transfer of the lux genes (luxCDABEG), which encode proteins involved in luminescence, a distinctive phenotype. Three hundred three luminous strains, most of which were recently isolated from nature and which represent 11 Aliivibrio, Photobacterium, and Vibrio species, were screened for incongruence of phylogenies based on a representative housekeeping gene (gyrB or pyrH) and a representative lux gene (luxA). Strains exhibiting incongruence were then subjected to detailed phylogenetic analysis of horizontal transfer by using multiple housekeeping genes (gyrB, recA, and pyrH) and multiple lux genes (luxCDABEG). In nearly all cases, housekeeping gene and lux gene phylogenies were congruent, and there was no instance in which the lux genes of one luminous species had replaced the lux genes of another luminous species. Therefore, the lux genes are predominantly vertically inherited in Vibrionaceae. The few exceptions to this pattern of congruence were as follows: (i) the lux genes of the only known luminous strain of Vibrio vulnificus, VVL1 (ATCC 43382), were evolutionarily closely related to the lux genes of Vibrio harveyi; (ii) the lux genes of two luminous strains of Vibrio chagasii, 21N-12 and SB-52, were closely related to those of V. harveyi and Vibrio splendidus, respectively; (iii) the lux genes of a luminous strain of Photobacterium damselae, BT-6, were closely related to the lux genes of the lux-rib(2) operon of Photobacterium leiognathi; and (iv) a strain of the luminous bacterium Photobacterium mandapamensis was found to be merodiploid for the lux genes, and the second set of lux genes was closely related to the lux genes of the lux-rib(2) operon of P. leiognathi. In none of these cases of apparent HGT, however, did acquisition of the lux genes correlate with phylogenetic divergence of the recipient strain from other members of its species. The results indicate that horizontal transfer of the lux genes in nature is rare and that horizontal acquisition of the lux genes apparently has not contributed to speciation in recipient taxa. PMID:18359809
Urbanczyk, Henryk; Ast, Jennifer C; Kaeding, Allison J; Oliver, James D; Dunlap, Paul V
Horizontal gene transfer (HGT) is thought to occur frequently in bacteria in nature and to play an important role in bacterial evolution, contributing to the formation of new species. To gain insight into the frequency of HGT in Vibrionaceae and its possible impact on speciation, we assessed the incidence of interspecies transfer of the lux genes (luxCDABEG), which encode proteins involved in luminescence, a distinctive phenotype. Three hundred three luminous strains, most of which were recently isolated from nature and which represent 11 Aliivibrio, Photobacterium, and Vibrio species, were screened for incongruence of phylogenies based on a representative housekeeping gene (gyrB or pyrH) and a representative lux gene (luxA). Strains exhibiting incongruence were then subjected to detailed phylogenetic analysis of horizontal transfer by using multiple housekeeping genes (gyrB, recA, and pyrH) and multiple lux genes (luxCDABEG). In nearly all cases, housekeeping gene and lux gene phylogenies were congruent, and there was no instance in which the lux genes of one luminous species had replaced the lux genes of another luminous species. Therefore, the lux genes are predominantly vertically inherited in Vibrionaceae. The few exceptions to this pattern of congruence were as follows: (i) the lux genes of the only known luminous strain of Vibrio vulnificus, VVL1 (ATCC 43382), were evolutionarily closely related to the lux genes of Vibrio harveyi; (ii) the lux genes of two luminous strains of Vibrio chagasii, 21N-12 and SB-52, were closely related to those of V. harveyi and Vibrio splendidus, respectively; (iii) the lux genes of a luminous strain of Photobacterium damselae, BT-6, were closely related to the lux genes of the lux-rib2 operon of Photobacterium leiognathi; and (iv) a strain of the luminous bacterium Photobacterium mandapamensis was found to be merodiploid for the lux genes, and the second set of lux genes was closely related to the lux genes of the lux-rib2 operon of P. leiognathi. In none of these cases of apparent HGT, however, did acquisition of the lux genes correlate with phylogenetic divergence of the recipient strain from other members of its species. The results indicate that horizontal transfer of the lux genes in nature is rare and that horizontal acquisition of the lux genes apparently has not contributed to speciation in recipient taxa.
Urbanczyk, Henryk; Ast, Jennifer C.; Kaeding, Allison J.; Oliver, James D.; Dunlap, Paul V.
A family II cellulose-binding domain (CBD) of an exoglucanase/xylanase (Cex) from the bacterium Cellulomonas fimi was replaced with the family I CBD of cellobiohydrolase I (CbhI) from the fungus Trichoderma reesei. Expression of the hybrid gene in Escherichia coli yielded up to 50 mg of the hybrid protein, CexCBDCbhI, per liter of culture supernatant. The hybrid was purified to homogeneity by affinity chromatography on cellulose. The relative association constants (Kr) for the binding of Cex, CexCBDCbhI, the catalytic domain of Cex (p33), and CbhI to bacterial microcrystalline cellulose (BMCC) were 14.9, 7.8, 0.8, and 10.6 liters g-1, respectively. Cex and CexCBDCbhI had similar substrate specificities and similar activities on crystalline and amorphous cellulose. Both released predominantly cellobiose and cellotriose from amorphous cellulose. CexCBDCbhI was two to three times less active than Cex on BMCC, but significantly more active than Cex on soluble cellulose and on xylan. Unlike Cex, the hybrid protein neither bound to alpha-chitin nor released small particles from dewaxed cotton fibers.
Tomme, P; Driver, D P; Amandoron, E A; Miller, R C; Antony, R; Warren, J; Kilburn, D G
A family II cellulose-binding domain (CBD) of an exoglucanase/xylanase (Cex) from the bacterium Cellulomonas fimi was replaced with the family I CBD of cellobiohydrolase I (CbhI) from the fungus Trichoderma reesei. Expression of the hybrid gene in Escherichia coli yielded up to 50 mg of the hybrid protein, CexCBDCbhI, per liter of culture supernatant. The hybrid was purified to homogeneity by affinity chromatography on cellulose. The relative association constants (Kr) for the binding of Cex, CexCBDCbhI, the catalytic domain of Cex (p33), and CbhI to bacterial microcrystalline cellulose (BMCC) were 14.9, 7.8, 0.8, and 10.6 liters g-1, respectively. Cex and CexCBDCbhI had similar substrate specificities and similar activities on crystalline and amorphous cellulose. Both released predominantly cellobiose and cellotriose from amorphous cellulose. CexCBDCbhI was two to three times less active than Cex on BMCC, but significantly more active than Cex on soluble cellulose and on xylan. Unlike Cex, the hybrid protein neither bound to alpha-chitin nor released small particles from dewaxed cotton fibers. PMID:7635821
Tomme, P; Driver, D P; Amandoron, E A; Miller, R C; Antony, R; Warren, J; Kilburn, D G
Jellyfish blooms have increased in coastal areas around the world and the outbreaks have become longer and more frequent over the past few decades. The Mediterranean Sea is among the heavily affected regions and the common bloom-forming taxa are scyphozoans Aurelia aurita s.l., Pelagia noctiluca, and Rhizostoma pulmo. Jellyfish have few natural predators, therefore their carcasses at the termination of a bloom represent an organic-rich substrate that supports rapid bacterial growth, and may have a large impact on the surrounding environment. The focus of this study was to explore whether jellyfish substrate have an impact on bacterial community phylotype selection. We conducted in situ jellyfish-enrichment experiment with three different jellyfish species. Bacterial dynamic together with nutrients were monitored to assess decaying jellyfish-bacteria dynamics. Our results show that jellyfish biomass is characterized by protein rich organic matter, which is highly bioavailable to 'jellyfish-associated' and 'free-living' bacteria, and triggers rapid shifts in bacterial population dynamics and composition. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis, we observed a rapid shift in community composition from unculturable Alphaproteobacteria to culturable species of Gammaproteobacteria and Flavobacteria. The results of sequence analyses of bacterial isolates and of total bacterial community determined by culture independent genetic analysis showed the dominance of the Pseudoalteromonadaceae and the Vibrionaceae families. Elevated levels of dissolved proteins, dissolved organic and inorganic nutrient release, bacterial abundance and carbon production as well as ammonium concentrations characterized the degradation process. The biochemical composition of jellyfish species may influence changes in the amount of accumulated dissolved organic and inorganic nutrients. Our results can contribute insights into possible changes in bacterial population dynamics and nutrient pathways following jellyfish blooms which have important implications for ecology of coastal waters. PMID:22745726
Tinta, Tinkara; Kogovšek, Tjaša; Malej, Alenka; Turk, Valentina
Background & Aims: To date, no studies concerning the presence of small intestinal bacterial overgrowth in patients with progressive familial intrahepatic cholestasis were published. Based upon characteristic of progressive familial intrahepatic cholestasis one can expect the coexistence of small intestinal bacterial overgrowth. The aim of the study was to assess the incidence of small intestinal bacterial overgrowth in patients with progressive familial intrahepatic cholestasis. Methods: 26 patients aged 8 to 25 years with progressive familial intrahepatic cholestasis were included in the study. Molecular analysis of ABCB11 gene was performed in the vast majority of patients. In all patients Z-score for body weight and height, biochemical tests (bilirubin, bile acid concentration, fecal fat excretion) were assessed. In all patients hydrogen-methane breath test was performed. Results: On the basis of first hydrogen-methane breath test, diagnosis of small intestinal bacterial overgrowth was confirmed in 9 patients (35%), 5 patients (19%) had borderline results. The second breath test was performed in 10 patients: in 3 patients results were still positive and 2 patients had a borderline result. The third breath test was conducted in 2 patients and positive results were still observed. Statistical analysis did not reveal any significant correlations between clinical, biochemical and therapeutic parameters in patients with progressive familial intrahepatic cholestasis and coexistence of small intestinal bacterial overgrowth. Conclusions: Our results suggest that small intestinal bacterial overgrowth is frequent in patients with progressive familial intrahepatic cholestasis. Moreover, it seems that this condition has the tendency to persist or recur, despite the treatment. PMID:24644547
Lisowska, Aleksandra; Kobelska-Dubiel, Natalia; Jankowska, Irena; Paw?owska, Joanna; Moczko, Jerzy; Walkowiak, Jaros?aw
Prokaryotic MazF family toxins cooccur with cognate antitoxins having divergent DNA-binding folds and can be of chromosomal or plasmid origin. Sequence similarity search was carried out to identify the Toxin–Antitoxin (TA) operons of MazF family followed by sequence analysis and phylogenetic studies. The genomic DNA upstream of the TA operons was searched for the presence of regulatory motifs. The MazF family toxins showed a conserved hydrophobic pocket in a multibinding site and are present in pathogenic bacteria. The toxins of the MazF family are associated with four main types of cognate antitoxin partners and cluster as a subfamily on the branches of the phylogenetic tree. This indicates that transmission of the entire operon is the dominant mode of inheritance. The plasmid borne TA modules were interspersed between the chromosomal TA modules of the same subfamily, compatible with a frequent interchange of TA genes between the chromosome and the plasmid akin to that observed for antibiotic resistance gens. The split network of the MazF family toxins showed the AbrB-linked toxins as a hub of horizontal gene transfer. Distinct motifs are present in the upstream region of each subfamily. The presence of MazF family TA modules in pathogenic bacteria and identification of a conserved binding pocket are significant for the development of novel antibacterials to disrupt the TA interaction. However, the role of TAs in stress resistance needs to be established. Phylogenetic studies provide insight into the evolution of MazF family TAs and effect on the bacterial genome.
Chopra, Nikita; Saumitra; Pathak, Abhinandan; Bhatnagar, Rakesh; Bhatnagar, Sonika
Teichoic acids and acidic capsular polysaccharides are major anionic cell wall polymers (APs) in many bacteria, with various critical cell functions, including maintenance of cell shape and structural integrity, charge and cation homeostasis, and multiple aspects of pathogenesis. We have identified the widespread LytR–Cps2A–Psr (LCP) protein family, of previously unknown function, as novel enzymes required for AP synthesis. Structural and biochemical analysis of several LCP proteins suggest that they carry out the final step of transferring APs from their lipid-linked precursor to cell wall peptidoglycan (PG). In Bacillus subtilis, LCP proteins are found in association with the MreB cytoskeleton, suggesting that MreB proteins coordinate the insertion of the major polymers, PG and AP, into the cell wall.
Kawai, Yoshikazu; Marles-Wright, Jon; Cleverley, Robert M; Emmins, Robyn; Ishikawa, Shu; Kuwano, Masayoshi; Heinz, Nadja; Bui, Nhat Khai; Hoyland, Christopher N; Ogasawara, Naotake; Lewis, Richard J; Vollmer, Waldemar; Daniel, Richard A; Errington, Jeff
We describe a conserved family of bacterial gene products that includes the VirB1 virulence factor encoded by tumor-inducing plasmids of Agrobacterium spp., proteins involved in conjugative DNA transfer of broad-host-range bacterial plasmids, and gene products that may be involved in invasion by Shigella spp. and Salmonella enterica. Sequence analysis and structural modeling show that the proteins in this group are related to chicken egg white lysozyme and are likely to adopt a lysozyme-like structural fold. Based on their similarity to lysozyme, we predict that these proteins have glycosidase activity. Iterative data base searches with three conserved sequence motifs from this protein family detect a more distant relationship to bacterial and bacteriophage lytic transglycosylases, and goose egg white lysozyme. Two acidic residues in the VirB1 protein of Agrobacterium tumefaciens form a putative catalytic dyad, Each of these residues was changed into the corresponding amide by site-directed mutagenesis. Strains of A. tumefaciens that express mutated VirB1 proteins have a significantly reduced virulence. We hypothesize that many bacterial proteins involved in export of macromolecules belong to a widespread class of hydrolases and cleave beta-1,4-glycosidic bonds as part of their function. Images Fig. 2 Fig. 4
Mushegian, A R; Fullner, K J; Koonin, E V; Nester, E W
Autotransporters are an extensive family of large secreted virulence-associated proteins of gram-negative bacteria. Secretion of such large proteins poses unique challenges to bacteria. We demonstrate that autotrans- porters from a wide variety of rod-shaped pathogens, including IcsA and SepA of Shigella flexneri, AIDA-I of diffusely adherent Escherichia coli, and BrkA of Bordetella pertussis, are localized to the bacterial pole. The
Sumita Jain; Peter van Ulsen; Inga Benz; M. Alexander Schmidt; Rachel Fernandez; Jan Tommassen; Marcia B. Goldberg
The SdpI family consists of putative bacterial toxin immunity and signal transduction proteins. One member of the family in Bacillus subtilis, SdpI, provides immunity to cells from cannibalism in times of nutrient limitation. SdpI family members are transmembrane proteins with 3, 4, 5, 6, 7, 8, or 12 putative transmembrane ?-helical segments (TMSs). These varied topologies appear to be genuine rather than artifacts due to sequencing or annotation errors. The basic and most frequently occurring element of the SdpI family has 6 TMSs. Homologues of all topological types were aligned to determine the homologous TMSs and loop regions, and the positive-inside rule was used to determine sidedness. The two most conserved motifs were identified between TMSs 1 and 2 and TMSs 4 and 5 of the 6 TMS proteins. These showed significant sequence similarity, leading us to suggest that the primordial precursor of these proteins was a 3 TMS–encoding genetic element that underwent intragenic duplication. Various deletional and fusional events, as well as intragenic duplications and inversions, may have yielded SdpI homologues with topologies of varying numbers and positions of TMSs. We propose a specific evolutionary pathway that could have given rise to these distantly related bacterial immunity proteins. We further show that genes encoding SdpI homologues often appear in operons with genes for homologues of SdpR, SdpI’s autorepressor. Our analyses allow us to propose structure–function relationships that may be applicable to most family members. Electronic supplementary material The online version of this article (doi:10.1007/s00232-010-9260-7) contains supplementary material, which is available to authorized users.
Povolotsky, Tatyana Leonidovna; Orlova, Ekaterina; Tamang, Dorjee G.
There are a variety of bacterial defense strategies to survive in a hostile environment. Generation of extracellular polysaccharides has proved to be a simple but effective strategy against the host's innate immune system. A comparative genomics approach led us to identify a new protein family termed Stealth, most likely involved in the synthesis of extracellular polysaccharides. This protein family is
Peter Sperisen; Christoph D. Schmid; Philipp Bucher; Olav Zilian
Background Microbial derived lipolytic hydrolysts are an important class of biocatalysts because of their huge abundance and ability to display bioactivities under extreme conditions. In spite of recent advances, our understanding of these enzymes remains rudimentary. The aim of our research is to advance our understanding by seeking for more unusual lipid hydrolysts and revealing their molecular structure and bioactivities. Methodology/Principal Findings Bacillus. pseudofirmus OF4 is an extreme alkaliphile with tolerance of pH up to 11. In this work we successfully undertook a heterologous expression of a gene estof4 from the alkaliphilic B. pseudofirmus sp OF4. The recombinant protein called EstOF4 was purified into a homologous product by Ni-NTA affinity and gel filtration. The purified EstOF4 was active as dimer with the molecular weight of 64 KDa. It hydrolyzed a wide range of substrates including p-nitrophenyl esters (C2–C12) and triglycerides (C2–C6). Its optimal performance occurred at pH 8.5 and 50°C towards p-nitrophenyl caproate and triacetin. Sequence alignment revealed that EstOF4 shared 71% identity to esterase Est30 from Geobacillus stearothermophilus with a typical lipase pentapeptide motif G91LS93LG95. A structural model developed from homology modeling revealed that EstOF4 possessed a typical esterase 6?/7? hydrolase fold and a cap domain. Site-directed mutagenesis and inhibition studies confirmed the putative catalytic triad Ser93, Asp190 and His220. Conclusion EstOF4 is a new bacterial esterase with a preference to short chain ester substrates. With a high sequence identity towards esterase Est30 and several others, EstOF4 was classified into the same bacterial lipolytic family, Family XIII. All the members in this family originate from the same bacterial genus, bacillus and display optimal activities from neutral pH to alkaline conditions with short and middle chain length substrates. However, with roughly 70% sequence identity, these enzymes showed hugely different thermal stabilities, indicating their diverse thermal adaptations via just changing a few amino acid residues.
Rao, Lang; Xue, Yanfen; Zheng, Yingying; Lu, Jian R.; Ma, Yanhe
There is current interest in biological sources of acetone, a volatile organic compound that impacts atmospheric chemistry. Here, we determined that leucine-dependent acetone formation is widespread in the Vibrionaceae. Sixteen Vibrio isolates, two Listonella species, and two Photobacterium angustum isolates produced acetone in the presence of l-leucine. Shewanella isolates produced much less acetone. Growth of Vibrio splendidus and P. angustum in a fermentor with controlled aeration revealed that acetone was produced after a lag in late logarithmic or stationary phase of growth, depending on the medium, and was not derived from acetoacetate by nonenzymatic decarboxylation in the medium. l-Leucine, but not d-leucine, was converted to acetone with a stoichiometry of approximately 0.61 mol of acetone per mol of l-leucine. Testing various potential leucine catabolites as precursors of acetone showed that only ?-ketoisocaproate was efficiently converted by whole cells to acetone. Acetone production was blocked by a nitrogen atmosphere but not by electron transport inhibitors, suggesting that an oxygen-dependent reaction is required for leucine catabolism. Metabolic labeling with deuterated (isopropyl-d7)-l-leucine revealed that the isopropyl carbons give rise to acetone with full retention of deuterium in each methyl group. These results suggest the operation of a new catabolic pathway for leucine in vibrios that is distinct from the 3-hydroxy-3-methylglutaryl-coenzyme A pathway seen in pseudomonads.
Nemecek-Marshall, Michele; Wojciechowski, Cheryl; Wagner, William P.; Fall, Ray
Plasmids are autonomously replicating extrachromosomal DNA molecules that often impart key phenotypes to their bacterial hosts. Plasmids are abundant in marine bacteria, but there is scant knowledge of the mechanisms that control their replication in these hosts. Here, we identified and characterized the factors governing replication of a new family of plasmids from marine bacteria, typified by the virulence-linked plasmid pB1067 of Vibrio nigripulchritudo. Members of this family are prevalent among, yet restricted to, the Vibrionaceae. Unlike almost all plasmid families characterized to date, the ori regions of these plasmids do not encode a Rep protein to initiate DNA replication; instead, the ori regions encode two partially complementary RNAs. The smaller, termed RNA I, is ?68-nt long and functions as a negative regulator and the key determinant of plasmid incompatibility. This Marine RNA-based (MRB) plasmid family is the first characterized family of replicons derived from marine bacteria. Only one other plasmid family (the ColE1 family) has previously been reported to rely on RNA-mediated replication initiation. However, since the sequences and structures of MRB RNA I transcripts are not related to those of ColE1 replicons, these two families of RNA-dependent replicons likely arose by convergent evolution.
Le Roux, Frederique; Davis, Brigid M.; Waldor, Matthew K.
Pasteurellaceae are bacteria with an important role as primary or opportunistic, mainly respiratory, pathogens in domestic and wild animals. Some species of Pasteurellaceae cause severe diseases with high economic losses in commercial animal husbandry and are of great diagnostic concern. Because of new data on the phylogeny of Pasteurellaceae, their taxonomy has recently been revised profoundly, thus requiring an improved phenotypic differentiation procedure to identify the individual species of this family. A new and simplified procedure to identify species of Actinobacillus, Avibacterium, Gallibacterium, Haemophilus, Mannheimia, Nicoletella, and Pasteurella, which are most commonly isolated from clinical samples of diseased animals in veterinary diagnostic laboratories, is presented in the current study. The identification procedure was evaluated with 40 type and reference strains and with 267 strains from routine diagnostic analysis of various animal species, including 28 different bacterial species. Type, reference, and field strains were analyzed by 16S ribosomal RNA (rrs) and rpoB gene sequencing for unambiguous species determination as a basis to evaluate the phenotypic differentiation schema. Primary phenotypic differentiation is based on beta-nicotinamide adenine dinucleotide (beta-NAD) dependence and hemolysis, which are readily determined on the isolation medium. The procedure divides the 28 species into 4 groups for which particular biochemical reactions were chosen to identify the bacterial species. The phenotypic identification procedure allowed researchers to determine the species of 240 out of 267 field strains. The procedure is an easy and cost-effective system for the rapid identification of species of the Pasteurellaceae family isolated from clinical specimens of animals. PMID:18987220
Dousse, Florence; Thomann, Andreas; Brodard, Isabelle; Korczak, Bozena M; Schlatter, Yvonne; Kuhnert, Peter; Miserez, Raymond; Frey, Joachim
UDP-glycosyltransferases (UGTs) catalyze the conjugation of a variety of small lipophilic molecules with uridine diphosphate (UDP) sugars, altering them into more water-soluble metabolites. Thereby, UGTs play an important role in the detoxification of xenobiotics and in the regulation of endobiotics. Recently, the genome sequence was reported for the two-spotted spider mite, Tetranychus urticae, a polyphagous herbivore damaging a number of agricultural crops. Although various gene families implicated in xenobiotic metabolism have been documented in T. urticae, UGTs so far have not. We identified 80 UGT genes in the T. urticae genome, the largest number of UGT genes in a metazoan species reported so far. Phylogenetic analysis revealed that lineage-specific gene expansions increased the diversity of the T. urticae UGT repertoire. Genomic distribution, intron-exon structure and structural motifs in the T. urticae UGTs were also described. In addition, expression profiling after host-plant shifts and in acaricide resistant lines supported an important role for UGT genes in xenobiotic metabolism. Expanded searches of UGTs in other arachnid species (Subphylum Chelicerata), including a spider, a scorpion, two ticks and two predatory mites, unexpectedly revealed the complete absence of UGT genes. However, a centipede (Subphylum Myriapoda) and a water flea and a crayfish (Subphylum Crustacea) contain UGT genes in their genomes similar to insect UGTs, suggesting that the UGT gene family might have been lost early in the Chelicerata lineage and subsequently re-gained in the tetranychid mites. Sequence similarity of T. urticae UGTs and bacterial UGTs and their phylogenetic reconstruction suggest that spider mites acquired UGT genes from bacteria by horizontal gene transfer. Our findings show a unique evolutionary history of the T. urticae UGT gene family among other arthropods and provide important clues to its functions in relation to detoxification and thereby host adaptation. PMID:24727020
Ahn, Seung-Joon; Dermauw, Wannes; Wybouw, Nicky; Heckel, David G; Van Leeuwen, Thomas
Background A novel Gram-negative, non-haemolytic, non-motile, rod-shaped bacterium was discovered in the lungs of a dead parakeet (Melopsittacus undulatus) that was kept in captivity in a petshop in Basel, Switzerland. The organism is described with a chemotaxonomic profile and the nearly complete genome sequence obtained through the assembly of short sequence reads. Results Genome sequence analysis and characterization of respiratory quinones, fatty acids, polar lipids, and biochemical phenotype is presented here. Comparison of gene sequences revealed that the most similar species is Pelistega europaea, with BLAST identities of only 93% to the 16S rDNA gene, 76% identity to the rpoB gene, and a similar GC content (~43%) as the organism isolated from the parakeet, DSM 24701 (40%). The closest full genome sequences are those of Bordetella spp. and Taylorella spp. High-throughput sequencing reads from the Illumina-Solexa platform were assembled with the Edena de novo assembler to form 195 contigs comprising the ~2 Mb genome. Genome annotation with RAST, construction of phylogenetic trees with the 16S rDNA (rrs) gene sequence and the rpoB gene, and phylogenetic placement using other highly conserved marker genes with ML Tree all suggest that the bacterial species belongs to the Alcaligenaceae family. Analysis of samples from cages with healthy parakeets suggested that the newly discovered bacterial species is not widespread in parakeet living quarters. Conclusions Classification of this organism in the current taxonomy system requires the formation of a new genus and species. We designate the new genus Basilea and the new species psittacipulmonis. The type strain of Basilea psittacipulmonis is DSM 24701 (= CIP 110308 T, 16S rDNA gene sequence Genbank accession number JX412111 and GI 406042063).
Interferons (IFNs) are secreted proteins of the cytokine family that regulate innate and adaptive immune responses to infection. Although the importance of IFNs in the antiviral response has long been appreciated, their role in bacterial infections is more complex and is currently a major focus of investigation. This review summarizes our current knowledge of the role of these cytokines in host defense against the bacterial pathogen Listeria monocytogenes and highlights recent discoveries on the molecular mechanisms evolved by this intracellular bacterium to subvert IFN responses.
Dussurget, Olivier; Bierne, Helene; Cossart, Pascale
Protein posttranslational modifications (PTMs), particularly phosphorylation, dramatically expand the complexity of cellular regulatory networks. Although cysteine (Cys) in various proteins can be subject to multiple PTMs, its phosphorylation was previously considered a rare PTM with almost no regulatory role assigned. We report here that phosphorylation occurs to a reactive cysteine residue conserved in the staphylococcal accessary regulator A (SarA)/MarR family global transcriptional regulator A (MgrA) family of proteins, and is mediated by the eukaryotic-like kinase-phosphatase pair Stk1-Stp1 in Staphylococcus aureus. Cys-phosphorylation is crucial in regulating virulence determinant production and bacterial resistance to vancomycin. Cell wall-targeting antibiotics, such as vancomycin and ceftriaxone, inhibit the kinase activity of Stk1 and lead to decreased Cys-phosphorylation of SarA and MgrA. An in vivo mouse model of infection established that the absence of stp1, which results in elevated protein Cys-phosphorylation, significantly reduces staphylococcal virulence. Our data indicate that Cys-phosphorylation is a unique PTM that can play crucial roles in bacterial signaling and regulation.
Sun, Fei; Ding, Yue; Ji, Quanjiang; Liang, Zhongjie; Deng, Xin; Wong, Catherine C. L.; Yi, Chengqi; Zhang, Liang; Xie, Sherrie; Alvarez, Sophie; Hicks, Leslie M.; Luo, Cheng; Jiang, Hualiang; Lan, Lefu; He, Chuan
The pyridine nucleotide cycle is a network of salvage and recycling routes maintaining homeostasis of NAD(P) cofactor pool in the cell. Nicotinamide mononucleotide (NMN) deamidase (EC 188.8.131.52), one of the key enzymes of the bacterial pyridine nucleotide cycle, was originally described in Enterobacteria, but the corresponding gene eluded identification for over 30 years. A genomics-based reconstruction of NAD metabolism across hundreds of bacterial species suggested that NMN deamidase reaction is the only possible way of nicotinamide salvage in the marine bacterium Shewanella oneidensis. This prediction was verified via purification of native NMN deamidase from S. oneidensis followed by the identification of the respective gene, termed pncC. Enzymatic characterization of the PncC protein, as well as phenotype analysis of deletion mutants, confirmed its proposed biochemical and physiological function in S. oneidensis. Of the three PncC homologs present in Escherichia coli, NMN deamidase activity was confirmed only for the recombinant purified product of the ygaD gene. A comparative analysis at the level of sequence and three-dimensional structure, which is available for one of the PncC family member, shows no homology with any previously described amidohydrolases. Multiple alignment analysis of functional and nonfunctional PncC homologs, together with NMN docking experiments, allowed us to tentatively identify the active site area and conserved residues therein. An observed broad phylogenomic distribution of predicted functional PncCs in the bacterial kingdom is consistent with a possible role in detoxification of NMN, resulting from NAD utilization by DNA ligase.
Galeazzi, Luca; Bocci, Paola; Amici, Adolfo; Brunetti, Lucia; Ruggieri, Silverio; Romine, Margaret; Reed, Samantha; Osterman, Andrei L.; Rodionov, Dmitry A.; Sorci, Leonardo; Raffaelli, Nadia
Background: Cellulases are glycosyl hydrolases — enzymes that hydrolyze glycosidic bonds. They have been widely studied using biochemical and microbiological techniques and have attracted industrial interest because of their potential in biomass conversion and in the paper and textile industries. Glycosyl hydrolases have lately been assigned to specific families on the basis of similarities in their amino acid sequences. The
Valérie Ducros; Mirjam Czjzek; Anne Belaich; Christian Gaudin; Henri-Pierre Fierobe; Jean-Pierre Belaich; Gideon J Davies; Richard Haser
The importance of accurate demographic information is reflected in the United States Constitution, Article 1, which provides for a decennial census of this country's human population. Bacteria also conduct a census of their population and do so more frequently, more efficiently, and as far we know, with little if any of the political contentiousness caused by human demographers. Many examples have been found of particular bacterial genes, operons, or regulons that are expressed preferentially at high cell densities. Many of these are regulated by proteins related to the LuxR and LuxI proteins of Vibrio fischeri, and by a diffusible pheromone called an autoinducer. LuxR and LuxI and their cognate autoinducer (3-oxohexanoyl homoserine lactone, designated VAI-1) provide an important model to describe the functions of this family of proteins. LuxR is a VAI-1 receptor and a VAI-1-dependent transcriptional activator, and LuxI directs the synthesis of VAI-1. VAI-1 diffuses across the bacterial envelope, and intracellular concentrations of it are therefore strongly increased by nearby VAI-1-producing bacteria. Similar systems regulate pathogenesis factors in Pseudomonas aeruginosa and Erwinia spp., as well as T1 plasmid conjugal transfer in Agrobacterium tumefaciens, and many other genes in numerous genera of gram-negative bacteria. Genetic analyses of these systems have revealed a high degree of functional conservation, while also uncovering features that are unique to each. PMID:8905097
Fuqua, C; Winans, S C; Greenberg, E P
The Sphingomonas paucimobilis beta-glucosidase Bgl1 is encoded by the bgl1 gene, associated with an 1308 bp open reading frame. The deduced protein has a potential signal peptide of 24 amino acids in the N-terminal region, and experimental evidence is consistent with the processing and export of the Bgl1 protein through the inner membrane to the periplasmic space. A His(6)-tagged 44.3 kDa protein was over-produced in the cytosol of Escherichia coli from a recombinant plasmid, which contained the S. paucimobilis bgl1 gene lacking the region encoding the putative signal peptide. Mature beta-glucosidase Bgl1 is specific for aryl-beta-glucosides and has no apparent activity with oligosaccharides derived from cellulose hydrolysis and other saccharides. A structure-based alignment established structural relations between S. paucimobilis Bgl1 and other members of the glycoside hydrolase (GH) family 1 enzymes. At subsite -1, the conserved residues required for catalysis by GH1 enzymes are present in Bgl1 with only minor differences. Major differences are found at subsite +1, the aglycone binding site. This alignment seeded a sequence-based phylogenetic analysis of GH1 enzymes, revealing an absence of horizontal transfer between phyla. Bootstrap analysis supported the definition of subfamilies and revealed that Bgl1, the first characterized beta-glucosidase from the genus Sphingomonas, represents a very divergent bacterial subfamily, closer to archaeal subfamilies than to others of bacterial origin.
Marques, Ana Rita; Coutinho, Pedro M; Videira, Paula; Fialho, Arsenio M; Sa-Correia, Isabel
Protein phosphorylation, catalyzed by the opposing actions of protein kinases and phosphatases, is a cornerstone of cellular signaling and regulation. Since their discovery, protein phosphatases have emerged as highly regulated enzymes with specificity that rivals their counteracting kinase partners. However, despite years of focused characterization in mammalian and yeast systems, many protein phosphatases in plants remain poorly or incompletely characterized. Here, we describe a bioinformatic, biochemical, and cellular examination of an ancient, Bacterial-like subclass of the phosphoprotein phosphatase (PPP) family designated the Shewanella-like protein phosphatases (SLP phosphatases). The SLP phosphatase subcluster is highly conserved in all plants, mosses, and green algae, with members also found in select fungi, protists, and bacteria. As in other plant species, the nucleus-encoded Arabidopsis (Arabidopsis thaliana) SLP phosphatases (AtSLP1 and AtSLP2) lack genetic redundancy and phylogenetically cluster into two distinct groups that maintain different subcellular localizations, with SLP1 being chloroplastic and SLP2 being cytosolic. Using heterologously expressed and purified protein, the enzymatic properties of both AtSLP1 and AtSLP2 were examined, revealing unique metal cation preferences in addition to a complete insensitivity to the classic serine/threonine PPP protein phosphatase inhibitors okadaic acid and microcystin. The unique properties and high conservation of the plant SLP phosphatases, coupled to their exclusion from animals, red algae, cyanobacteria, archaea, and most bacteria, render understanding the function(s) of this new subclass of PPP family protein phosphatases of particular interest. PMID:21976480
Uhrig, R Glen; Moorhead, Greg B
Bacteria transcriptional regulators are classified by their functional and sequence similarities. Member of the TetR/AcrR family is two-domain proteins including an N-terminal HTH DNA-binding motif and a C-terminal ligand recognition domain. The C-terminal ligand recognition domain can recognize the very same compounds as their target transporters transferred. TetRs act as chemical sensors to monitor both the cellular environmental dynamics and their regulated genes underlying many events, such as antibiotics production, osmotic stress, efflux pumps, multidrug resistance, metabolic modulation, and pathogenesis. Compounds targeting Mycobacterium tuberculosis ethR represent promising novel antibiotic potentiater. TetR-mediated multidrug efflux pumps regulation might be good target candidate for the discovery of better new antibiotics against drug resistance. PMID:23602932
Deng, Wanyan; Li, Chunmei; Xie, Jianping
The vital task of vectorial solute transport is often energised by a plasma membrane, proton-motive V-ATPase. However, its proposed partner, an apical alkali-metal/proton exchanger, has remained elusive. Here, both FlyAtlas microarray data and in situ analyses demonstrate that the bacterial kefB and kefC (members of the CPA2 family) homologues in Drosophila, CG10806 and CG31052, respectively, are both co-expressed with V-ATPase genes in transporting epithelia. Immunocytochemistry localises endogenous CG10806 and CG31052 to the apical plasma membrane of the Malpighian (renal) tubule. YFP-tagged CG10806 and CG31052 both localise to the plasma membrane of Drosophila S2 cells, and when driven in principal cells of the Malpighian tubule, they localise specifically to the apical plasma membrane. V-ATPase-energised fluid secretion is affected by overexpression of CG10806, but not CG31052; in the former case, overexpression causes higher basal rates, but lower stimulated rates, of fluid secretion compared with parental controls. Overexpression also impacts levels of secreted Na+ and K+. Both genes rescue exchanger-deficient (nha1 nhx1) yeast, but act differently; CG10806 is driven predominantly to the plasma membrane and confers protection against excess K+, whereas CG31052 is expressed predominantly on the vacuolar membrane and protects against excess Na+. Thus, both CG10806 and CG31052 are functionally members of the CPA2 gene family, colocalise to the same apical membrane as the plasma membrane V-ATPase and show distinct ion specificities, as expected for the Wieczorek exchanger. PMID:18628302
Day, Jonathan P; Wan, Susan; Allan, Adrian K; Kean, Laura; Davies, Shireen A; Gray, Joe V; Dow, Julian A T
Eukaryotic sugar transporters of the MFS and SWEET superfamilies consist of 12 and 7 ?-helical transmembrane domains (TMs), respectively. Structural analyses indicate that MFS transporters evolved from a series of tandem duplications of an ancestral 3-TM unit. SWEETs are heptahelical proteins carrying a tandem repeat of 3-TM separated by a single TM. Here, we show that prokaryotes have ancestral SWEET homologs with only 3-TM and that the Bradyrhizobium japonicum SemiSWEET1, like Arabidopsis SWEET11, mediates sucrose transport. Eukaryotic SWEETs most likely evolved by internal duplication of the 3-TM, suggesting that SemiSWEETs form oligomers to create a functional pore. However, it remains elusive whether the 7-TM SWEETs are the functional unit or require oligomerization to form a pore sufficiently large to allow for sucrose passage. Split ubiquitin yeast two-hybrid and split GFP assays indicate that Arabidopsis SWEETs homo- and heterooligomerize. We examined mutant SWEET variants for negative dominance to test if oligomerization is necessary for function. Mutation of the conserved Y57 or G58 in SWEET1 led to loss of activity. Coexpression of the defective mutants with functional A. thaliana SWEET1 inhibited glucose transport, indicating that homooligomerization is necessary for function. Collectively, these data imply that the basic unit of SWEETs, similar to MFS sugar transporters, is a 3-TM unit and that a functional transporter contains at least four such domains. We hypothesize that the functional unit of the SWEET family of transporters possesses a structure resembling the 12-TM MFS structure, however, with a parallel orientation of the 3-TM unit. PMID:24027245
Xuan, Yuan Hu; Hu, Yi Bing; Chen, Li-Qing; Sosso, Davide; Ducat, Daniel C; Hou, Bi-Huei; Frommer, Wolf B
The Phoenix 100 ID\\/AST system (Becton Dickinson Co., Sparks, Md.) is an automated system for the identification and antimicrobial susceptibility testing of bacterial isolates. This system with its negative identification (NID) panel was evaluated for its accuracy in the identification of 507 isolates of the family Enterobacteriaceae, 57 other nonenteric gram-negative isolates that are commonly isolated in clinical microbi- ology
Caroline M. O'Hara
Bacteria inhibitory to fish larval pathogenic bacteria were isolated from two turbot larva rearing farms over a 1-year period. Samples were taken from the rearing site, e.g., tank walls, water, and feed for larvae, and bacteria with antagonistic activity against Vibrio anguillarum were isolated using a replica plating assay. Approximately 19,000 colonies were replica plated from marine agar plates, and 341 strains were isolated from colonies causing clearing zones in a layer of V. anguillarum. When tested in a well diffusion agar assay, 173 strains retained the antibacterial activity against V. anguillarum and Vibrio splendidus. Biochemical tests identified 132 strains as Roseobacter spp. and 31 as Vibrionaceae strains. Partial sequencing of the 16S rRNA gene of three strains confirmed the identification as Roseobacter gallaeciensis. Roseobacter spp. were especially isolated in the spring and early summer months. Subtyping of the 132 Roseobacter spp. strains by randomly amplified polymorphic DNA with two primers revealed that the strains formed a very homogeneous group. Hence, it appears that the same subtype was present at both fish farms and persisted during the 1-year survey. This indicates either a common, regular source of the subtype or the possibility that a particular subtype has established itself in some areas of the fish farm. Thirty-one antagonists were identified as Vibrio spp., and 18 of these were V. anguillarum but not serotype O1 or O2. Roseobacter spp. strains were, in particular, isolated from the larval tank walls, and it may be possible to establish an antagonistic, beneficial microflora in the rearing environment of turbot larvae and thereby limit survival of pathogenic bacteria.
Hjelm, Mette; Riaza, Ana; Formoso, Fernanda; Melchiorsen, Jette; Gram, Lone
Detection of the human pathogen Vibrio parahaemolyticus often relies on molecular biological analysis of species-specific virulence factor genes. These genes have been employed in determinations of V. parahaemolyticus population numbers and the prevalence of pathogenic V. parahaemolyticus strains. Strains of the Vibrionaceae species Photobacterium damselae, Vibrio diabolicus, Vibrio harveyi, and Vibrio natriegens, as well as strains similar to Vibrio tubiashii, were isolated from a pristine salt marsh estuary. These strains were examined for the V. parahaemolyticus hemolysin genes tdh, trh, and tlh and for the V. parahaemolyticus type III secretion system 2? gene vscC2 using established PCR primers and protocols. Virulence-related genes occurred at high frequencies in non-V. parahaemolyticus Vibrionaceae species. V. diabolicus was of particular interest, as several strains were recovered, and the large majority (>83%) contained virulence-related genes. It is clear that detection of these genes does not ensure correct identification of virulent V. parahaemolyticus. Further, the occurrence of V. parahaemolyticus-like virulence factors in other vibrios potentially complicates tracking of outbreaks of V. parahaemolyticus infections.
Klein, Savannah L.; Gutierrez West, Casandra K.; Mejia, Diana M.
Crystal structure of Vibrionaceae Photobacterium sp. JT-ISH-224 alpha2,6-sialyltransferase in a ternary complex with donor product CMP and acceptor substrate lactose: catalytic mechanism and substrate recognition.
Sialyltransferases are a family of glycosyltransferases that catalyze the transfer of N-acetylneuraminic acid residues from cytidine monophosphate N-acetylneuraminic acid (CMP-NeuAc) as a donor substrate to the carbohydrate groups of glycoproteins and glycolipids as acceptor substrates. We determined the crystal structure of Delta16psp26ST, the N-terminal truncated form of alpha2,6-sialyltransferase from Vibrionaceae Photobacterium sp. JT-ISH-224, complexed with a donor product CMP and an acceptor substrate lactose. Delta16psp26ST has three structural domains. Domain 1 belongs to the immunoglobulin-like beta-sandwich fold, and domains 2 and 3 form the glycosyltransferase-B structure. The CMP and lactose were bound in the deep cleft between domains 2 and 3. In the structure, only Asp232 was within hydrogen-binding distance of the acceptor O6 carbon of the galactose residue in lactose, and His405 was within hydrogen-binding distance of the phosphate oxygen of CMP. Mutation of these residues greatly decreased the activity of the enzyme. These structural and mutational results indicated that Asp232 might act as a catalytic base for deprotonation of the acceptor substrate, and His405 might act as a catalytic acid for protonation of the donor substrate. These findings are consistent with an in-line-displacement reaction mechanism in which Delta16psp26ST catalyzes the inverting transfer reaction. Unlike the case with multifunctional sialyltransferase (Delta24PmST1) complexed with CMP and lactose, the crystal structure of which was recently reported, the alpha2,6 reaction specificity of Delta16psp26ST is likely to be determined by His123. PMID:17962295
Kakuta, Yoshimitsu; Okino, Nozomu; Kajiwara, Hitomi; Ichikawa, Masako; Takakura, Yoshimitsu; Ito, Makoto; Yamamoto, Takeshi
Background Bacterial penicillin-binding proteins and ?-lactamases (PBP-?Ls) constitute a large family of serine proteases that perform essential functions in the synthesis and maintenance of peptidoglycan. Intriguingly, genes encoding PBP-?L homologs occur in many metazoan genomes including humans. The emerging role of LACTB, a mammalian mitochondrial PBP-?L homolog, in metabolic signaling prompted us to investigate the evolutionary history of metazoan PBP-?L proteins. Results Metazoan PBP-?L homologs including LACTB share unique structural features with bacterial class B low molecular weight penicillin-binding proteins. The amino acid residues necessary for enzymatic activity in bacterial PBP-?L proteins, including the catalytic serine residue, are conserved in all metazoan homologs. Phylogenetic analysis indicated that metazoan PBP-?L homologs comprise four alloparalogus protein lineages that derive from ?-proteobacteria. Conclusion While most components of the peptidoglycan synthesis machinery were dumped by early eukaryotes, a few PBP-?L proteins were conserved and are found in metazoans including humans. Metazoan PBP-?L homologs are active-site-serine enzymes that probably have distinct functions in the metabolic circuitry. We hypothesize that PBP-?L proteins in the early eukaryotic cell enabled the degradation of peptidoglycan from ingested bacteria, thereby maximizing the yield of nutrients and streamlining the cell for effective phagocytotic feeding.
The nucleoside monophosphate kinases (NMPK) are important enzymes that control the ratio of mono- and di-phosphate nucleosides and participate in gene regulation and signal transduction in the cell. However, despite their importance only several 3D structures were experimentally determined in contrast to the wealth of sequences available for each of the NMPK families. To fill this gap we present a Web-based database containing structural models for all proteins of the five bacterial nucleoside monophosphate kinase (bNMPK) families. The models were computed by means of homology-based approach using a few experimentally determined bNMPK structures. The database also contains pK(a) values and their components calculated for the homology-based 3D models, which is a unique feature of the database. The BActerial Nucleoside MOnophosphate KInases (BANMOKI) database is freely accessible (http://www.ces.clemson.edu/compbio/banmoki) and offers an easy user-friendly interface for browsing, searching and downloading content of the database. The users can investigate, using the searching tools of the database, the properties of the bNMP kinases in respect to sequence composition, electrostatic interactions and structural differences. PMID:17320167
Kundrotas, Petras; Georgieva, Paulina; Shosheva, Alexandra; Christova, Petya; Alexov, Emil
There is growing appreciation that resident glial cells can initiate and/or regulate inflammation following trauma or infection in the central nervous system (CNS). We have previously demonstrated the ability of microglia and astrocytes to respond to bacterial pathogens or their products by rapid production of inflammatory mediators, followed by the production of the immunosuppressive cytokine interleukin (IL)?10. IL-19, another member of the IL-10 family of cytokines, has been studied in the context of a number of inflammatory conditions in the periphery and is known to modulate immune cell activity. In the present study, we demonstrate the constitutive and/or inducible expression of IL-19 and its cognate receptor subunits, IL-19R? and IL-19R? (also known as IL-20R1 and IL-20R2, and IL-20RA and IL-20RB), in mouse brain tissue, and by primary murine and human astrocytes. We also provide evidence for the presence of a novel truncated IL-19R? transcript variant in mouse brain tissue, but not glial cells, that shows reduced expression following bacterial infection. Importantly, IL-19R functionality in glia is indicated by the ability of IL-19 to regulate signaling component expression in these cells. Furthermore, while IL-19 itself had no effect on glial cytokine production, IL-19 treatment of bacterially infected or Toll-like receptor ligand stimulated astrocytes significantly attenuated pro-inflammatory cytokine production. The bacterially induced production of IL-19 by these resident CNS cells, the constitutive expression of its cognate receptor subunits, and the immunomodulatory effects of this cytokine, suggest a novel mechanism by which astrocytes can regulate CNS inflammation. PMID:24677051
Cooley, Ian D; Chauhan, Vinita S; Donneyz, Miguel A; Marriott, Ian
There is growing appreciation that resident glial cells can initiate and/or regulate inflammation following trauma or infection in the central nervous system (CNS). We have previously demonstrated the ability of microglia and astrocytes to respond to bacterial pathogens or their products by rapid production of inflammatory mediators, followed by the production of the immunosuppressive cytokine interleukin (IL)210. IL-19, another member of the IL-10 family of cytokines, has been studied in the context of a number of inflammatory conditions in the periphery and is known to modulate immune cell activity. In the present study, we demonstrate the constitutive and/or inducible expression of IL-19 and its cognate receptor subunits, IL-19R? and IL-19R? (also known as IL-20R1 and IL-20R2, and IL-20RA and IL-20RB), in mouse brain tissue, and by primary murine and human astrocytes. We also provide evidence for the presence of a novel truncated IL-19R? transcript variant in mouse brain tissue, but not glial cells, that shows reduced expression following bacterial infection. Importantly, IL-19R functionality in GLIA is indicated by the ability of IL-19 to regulate signaling component expression in these cells. Furthermore, while IL-19 itself had no effect on glial cytokine production, IL-19 treatment of bacterially infected or Toll-like receptor ligand stimulated astrocytes significantly attenuated pro-inflammatory cytokine production. The bacterially induced production of IL-19 by these resident CNS cells, the constitutive expression of its cognate receptor subunits, and the immunomodulatory effects of this cytokine, suggest a novel mechanism by which astrocytes can regulate CNS inflammation.
Cooley, Ian D.; Chauhan, Vinita S.; Donneyz, Miguel A.; Marriott, Ian
The objective of this study was to determine the differences in disease resistance against artificial infection with Aeromonas hydrophila between genetically different common carp families. Four strains differing in their origin and breeding history were selected from the live gene bank of common carp maintained at the Research Institute for Fisheries, Aquaculture and Irrigation (HAKI, Szarvas, Hungary) to establish families with wide genetic background: Szarvas 15 (15), an inbred mirror line; Tata (T) scaly noble carp; Duna (D), a Hungarian wild carp and Amur (A), an East Asian wild carp. A diallele mating structure was used to allow the assessment of genetic variation within and between the tested 96 families for a variety of traits. The existing technologies of fertilization and incubation of carp eggs, as well as larval and fingerling rearing had been modified because of the large number of baseline populations. Two challenge trials of the 96 families of carp with Aeromonas hydrophila were done. The 10 most resistant and 10 most susceptible families to A. hydrophila were identified from these two challenges. The crosses that produced the most resistant families were mainly those having parents from Tata and Szarvas 15 domesticated strains, while the most susceptible families were from the wild strains Duna and Amur. PMID:21118271
Jeney, G; Ardó, L; Rónyai, A; Bercsényi, M; Jeney, Z
The Lyme disease spirochete, Borrelia burgdorferi, encodes a novel type of DNA-binding protein named EbfC. Orthologs of EbfC are encoded by a wide range of bacterial species, so characterization of the borrelial protein has implications that span the eubacterial kingdom. The present work defines the DNA sequence required for high-affinity binding by EbfC to be the 4 bp broken palindrome GTnAC, where ‘n’ can be any nucleotide. Two high-affinity EbfC-binding sites are located immediately 5? of B. burgdorferi erp transcriptional promoters, and binding of EbfC was found to alter the conformation of erp promoter DNA. Consensus EbfC-binding sites are abundantly distributed throughout the B. burgdorferi genome, occurring approximately once every 1 kb. These and other features of EbfC suggest that this small protein and its orthologs may represent a distinctive type of bacterial nucleoid-associated protein. EbfC was shown to bind DNA as a homodimer, and site-directed mutagenesis studies indicated that EbfC and its orthologs appear to bind DNA via a novel ?-helical ‘tweezer’-like structure.
Riley, Sean P.; Bykowski, Tomasz; Cooley, Anne E.; Burns, Logan H.; Babb, Kelly; Brissette, Catherine A.; Bowman, Amy; Rotondi, Matthew; Miller, M. Clarke; DeMoll, Edward; Lim, Kap; Fried, Michael G.; Stevenson, Brian
Quinolone antibiotics are clinically important drugs that target bacterial DNA replication and chromosome segregation. Although the AcrAB-family efflux pumps generally protect bacteria from such drugs, the physiological role of these efflux systems and their interplay with other cellular events are poorly explored. Here, we report an intricate relationship between antibiotic resistance and cell polarity in the model bacterium Caulobacter crescentus. We show that a polarity landmark protein, TipN, identified by virtue of its ability to direct flagellum placement to the new cell pole, protects cells from toxic misregulation of an AcrAB efflux pump through a cis-encoded nalidixic acid-responsive transcriptional repressor. Alongside the importance of polarity in promoting the inheritance and activity of virulence functions including motility, we can now ascribe to it an additional role in drug resistance that is distinct from classical efflux mechanisms. PMID:24726830
Kirkpatrick, Clare L; Viollier, Patrick H
Eubacteria and archaea contain a variety of actin-like proteins (ALPs) that form filaments with surprisingly diverse architectures, assembly dynamics, and cellular functions. Although there is much data supporting differences between ALP families, there is little data regarding conservation of structure and function within these families. We asked whether the filament architecture and biochemical properties of the best-understood prokaryotic actin, ParM from plasmid R1, are conserved in a divergent member of the ParM family from plasmid pB171. Previous work demonstrated that R1 ParM assembles into filaments that are structurally distinct from actin and the other characterized ALPs. They also display three biophysical properties thought to be essential for DNA segregation: 1) rapid spontaneous nucleation, 2) symmetrical elongation, and 3) dynamic instability. We used microscopic and biophysical techniques to compare and contrast the architecture and assembly of these related proteins. Despite being only 41% identical, R1 and pB171 ParMs polymerize into nearly identical filaments with similar assembly dynamics. Conservation of the core assembly properties argues for their importance in ParM-mediated DNA segregation and suggests that divergent DNA-segregating ALPs with different assembly properties operate via different mechanisms.
Rivera, Christopher R.; Kollman, Justin M.; Polka, Jessica K.; Agard, David A.; Mullins, R. Dyche
Protein phosphorylation, catalyzed by the opposing actions of protein kinases and phosphatases, is a cornerstone of cellular signaling and regulation. Since their discovery, protein phosphatases have emerged as highly regulated enzymes with specificity that rivals their counteracting kinase partners. However, despite years of focused characterization in mammalian and yeast systems, many protein phosphatases in plants remain poorly or incompletely characterized. Here, we describe a bioinformatic, biochemical, and cellular examination of an ancient, Bacterial-like subclass of the phosphoprotein phosphatase (PPP) family designated the Shewanella-like protein phosphatases (SLP phosphatases). The SLP phosphatase subcluster is highly conserved in all plants, mosses, and green algae, with members also found in select fungi, protists, and bacteria. As in other plant species, the nucleus-encoded Arabidopsis (Arabidopsis thaliana) SLP phosphatases (AtSLP1 and AtSLP2) lack genetic redundancy and phylogenetically cluster into two distinct groups that maintain different subcellular localizations, with SLP1 being chloroplastic and SLP2 being cytosolic. Using heterologously expressed and purified protein, the enzymatic properties of both AtSLP1 and AtSLP2 were examined, revealing unique metal cation preferences in addition to a complete insensitivity to the classic serine/threonine PPP protein phosphatase inhibitors okadaic acid and microcystin. The unique properties and high conservation of the plant SLP phosphatases, coupled to their exclusion from animals, red algae, cyanobacteria, archaea, and most bacteria, render understanding the function(s) of this new subclass of PPP family protein phosphatases of particular interest.
Uhrig, R. Glen; Moorhead, Greg B.
Myxococcus xanthus has a large number of histidine kinase (HK) signal transduction proteins and many of these HKs are important for fruiting body development. Nla6S is an uncharacterized HK that lacks many of the conserved sequence motifs of typical HK proteins. In this study, we report that expression of the nla6S gene increases about sixfold during fruiting body development, that the Nla6S protein has the in vitro properties of HKs and that Nla6S is the prototype for a new family of HKs. To date, these Nla6-like HKs are found only in fruiting members of the Cystobacterineae suborder of the myxobacteria. PMID:22812452
Sarwar, Zaara; Garza, Anthony G
The crystal structure of a family-III cellulose-binding domain (CBD) from the cellulosomal scaffoldin subunit of Clostridium thermocellum has been determined at 1.75 A resolution. The protein forms a nine-stranded beta sandwich with a jelly roll topology and binds a calcium ion. conserved, surface-exposed residues map into two defined surfaces located on opposite sides of the molecule. One of these faces is dominated by a planar linear strip of aromatic and polar residues which are proposed to interact with crystalline cellulose. The other conserved residues are contained in a shallow groove, the function of which is currently unknown, and which has not been observed previously in other families of CBDs. On the basis of modeling studies combined with comparisons of recently determined NMR structures for other CBDs, a general model for the binding of CBDs to cellulose is presented. Although the proposed binding of the CBD to cellulose is essentially a surface interaction, specific types and combinations of amino acids appear to interact selectively with glucose moieties positioned on three adjacent chains of the cellulose surface. The major interaction is characterized by the planar strip of aromatic residues, which align along one of the chains. In addition, polar amino acid residues are proposed to anchor the CBD molecule to two other adjacent chains of crystalline cellulose. Images
Tormo, J; Lamed, R; Chirino, A J; Morag, E; Bayer, E A; Shoham, Y; Steitz, T A
The presence of the (Gly-Xaa-Yaa)n open reading frames in different bacteria predicts the existence of an expanded family of collagen-like proteins. To further explore the triple-helix motif and stabilization mechanisms in the absence of hydroxyproline (Hyp), predicted novel collagen-like proteins from Gram-positive and -negative bacteria were expressed in Escherichia coli and characterized. Soluble proteins capable of successful folding and in vitro refolding were observed for collagen proteins from Methylobacterium sp 4-46, Rhodopseudomonas palustris and Solibacter usitatus. In contrast, all protein constructs from Clostridium perfringens were found predominantly in inclusion bodies. However, attachment of a heterologous N-terminal or C-terminal non-collagenous folding domain induced the Clostridium perfringens collagen domain to fold and become soluble. The soluble constructs from different bacteria had typical collagen triple-helical features and showed surprisingly similar thermal stabilities despite diverse amino acid compositions. These collagen-like proteins provide a resource for the development of biomaterials with new properties.
Xu, Chunying; Yu, Zhuoxin; Inouye, Masayori; Brodsky, Barbara; Mirochnitchenko, Oleg
The cycle inhibiting factor (Cif) produced by enteropathogenic and enterohemorrhagic Escherichia coli was the first cyclomodulin to be identified that is injected into host cells via the type III secretion machinery. Cif provokes cytopathic effects characterized by G1 and G2 cell cycle arrests, accumulation of the cyclin-dependent kinase inhibitors (CKIs) p21waf1/cip1 and p27kip1 and formation of actin stress fibres. The X-ray crystal structure of Cif revealed it to be a divergent member of a superfamily of enzymes including cysteine proteases and acetyltransferases that share a conserved catalytic triad. Here we report the discovery and characterization of four Cif homologs encoded by different pathogenic or symbiotic bacteria isolated from vertebrates or invertebrates. Cif homologs from the enterobacteria Yersinia pseudotuberculosis, Photorhabdus luminescens, Photorhabdus asymbiotica and the ?-proteobacterium Burkholderia pseudomallei all induce cytopathic effects identical to those observed with Cif from pathogenic E. coli. Although these Cif homologs are remarkably divergent in primary sequence, the catalytic triad is strictly conserved and was shown to be crucial for cell cycle arrest, cytoskeleton reorganization and CKIs accumulation. These results reveal that Cif proteins form a growing family of cyclomodulins in bacteria that interact with very distinct hosts including insects, nematodes and humans.
Jubelin, Gregory; Chavez, Carolina Varela; Taieb, Frederic; Banfield, Mark J.; Samba-Louaka, Ascel; Nobe, Rika; Nougayrede, Jean-Philippe; Zumbihl, Robert; Givaudan, Alain; Escoubas, Jean-Michel; Oswald, Eric
Data shows that elevated sialidase in bacterial vaginosis patients correlates to premature births in women. Bacterial sialidase also plays a significant role in the unusual colonization of Pseudomonas aeruginosa in cystic fibrosis patients. Crystals of Salmonella sialidase have been reproduced and are used for studying the inhibitor-enzyme complexes. These inhibitors may also be used to inhibit a trans-sialidase of Trypanosome cruzi, a very similar enzyme to bacterial sialidase, therefore preventing T. cruzi infection, the causitive agent of Chagas' disease. The Center for Macromolecular Crystallography suggests that inhibitors of bacterial sialidases can be used as prophylactic drugs to prevent bacterial infections in these critical cases.
Individual Neisseria gonorrhoeae colony opacity-associated (Opa) protein variants can bind up to four dif- ferent carcinoembryonic antigen-related cellular adhesion molecule (CEACAM) receptors. Most human cells encountered by gonococci express a combination of CEACAM receptors, thereby complicating the elucidation of intracellular signaling pathways triggered by individual receptors. Here, we compare the process of bacterial engulfment by a panel of stably transfected
Shannon E. McCaw; Edward H. Liao; Scott D. Gray-Owen
\\u000a The human gastrointestinal tract typically contains 300–500 bacterial species. Most bacterial species are acquired during\\u000a the birth process and although some changes to the flora may occur during later stages of life, the composition of the intestinal\\u000a microflora remains relatively constant. Small bowel bacterial overgrowth (SBBO) is defined as an excessive increase in the\\u000a number of bacteria in the upper
Rosemary J. Young; Jon A. Vanderhoof
The global dissemination, potential activity in diverse species and broad resistance spectrum conferred by the aminoglycoside-resistance ribosomal RNA methyltransferases make them a significant potential new threat to the efficacy of aminoglycoside antibiotics in the treatment of serious bacterial infections. The N1 methylation of adenosine 1408 (m(1)A1408) confers resistance to structurally diverse aminoglycosides, including kanamycin, neomycin and apramycin. The limited analyses to date of the enzymes responsible have identified common features but also potential differences in their molecular details of action. Therefore, with the goal of expanding the known 16S rRNA (m(1)A1408) methyltransferase family as a platform for developing a more complete mechanistic understanding, we report here the cloning, expression and functional analyses of four hypothetical aminoglycoside-resistance rRNA methyltransferases from recent genome sequences of diverse bacterial species. Each of the genes produced a soluble, folded protein with a secondary structure, as determined from circular dichroism (CD) spectra, consistent with enzymes for which high-resolution structures are available. For each enzyme, antibiotic minimum inhibitory concentration (MIC) assays revealed a resistance spectrum characteristic of the known 16S rRNA (m(1)A1408) methyltransferases and the modified nucleotide was confirmed by reverse transcription as A1408. In common with other family members, higher binding affinity for the methylation reaction by-product S-adenosylhomocysteine (SAH) than the cosubstrate S-adenosyl-L-methionine (SAM) was observed for three methyltransferases, while one unexpectedly showed no measurable affinity for SAH. Collectively, these results confirm that each hypothetical enzyme is a functional 16S rRNA (m(1)A1408) methyltransferase but also point to further potential mechanistic variation within this enzyme family. PMID:24963996
Witek, Marta A; Conn, Graeme L
The scleractinian coral Porites lutea, an important reef-building coral on western Indian Ocean reefs (WIO), is affected by a newly-reported white syndrome (WS) the Porites white patch syndrome (PWPS). Histopathology and culture-independent molecular techniques were used to characterise the microbial communities associated with this emerging disease. Microscopy showed extensive tissue fragmentation generally associated with ovoid basophilic bodies resembling bacterial aggregates. Results of 16S rRNA sequence analysis revealed a high variability between bacterial communities associated with PWPS-infected and healthy tissues in P. lutea, a pattern previously reported in other coral diseases such as black band disease (BBD), white band disease (WBD) and white plague diseases (WPD). Furthermore, substantial variations in bacterial communities were observed at the different sampling locations, suggesting that there is no strong bacterial association in Porites lutea on WIO reefs. Several sequences affiliated with potential pathogens belonging to the Vibrionaceae and Rhodobacteraceae were identified, mainly in PWPS-infected coral tissues. Among them, only two ribotypes affiliated to Shimia marina (NR043300.1) and Vibrio hepatarius (NR025575.1) were consistently found in diseased tissues from the three geographically distant sampling localities. The role of these bacterial species in PWPS needs to be tested experimentally. PMID:24391819
Séré, Mathieu G; Tortosa, Pablo; Chabanet, Pascale; Turquet, Jean; Quod, Jean-Pascal; Schleyer, Michael H
Summary Luminescent bacteria (?-Proteobacteria: Vibrionaceae) are found in complex bilobed light organs of both sepiolid and loliginid squids (Mollusca: Cephalopoda). Despite the existence of multiple strain colonization between Vibrio bacteria and loliginid squids, specificity at the genus level still exists and may influence interactions between symbiotic and free-living stages of the symbiont. The environmentally transmitted behaviour of Vibrio symbionts bestows a certain degree of recognition that exists prior and subsequent to the colonization process. Therefore, we identified bacterial genes required for successful colonization of loliginid light organs by examining transcripts solely expressed in either the light organ or free-living stages. Selective capture of transcribed sequences (SCOTS) was used to differentiate genes expressed by the same bacterium when thriving in two different environments (i.e. loliginid light organs and seawater). Genes specific for squid light organs included vulnibactin synthetase, outer membrane protein W and dihydroxy dehydratase, which have been associated with the maintenance of bacterial host associations in other systems. In contrast, genes that were solely expressed in the free-living condition consisted of transcripts recognized as important factors for bacterial survival in the environment. These transcripts included genes for methyl accepting chemotaxis proteins, arginine decarboxylase and chitinase. These results provide valuable information regarding mechanisms determining specificity, establishment, and maintenance of bacteria–squid associations.
Guerrero-Ferreira, Ricardo C.; Nishiguchi, Michele K.
Bacterial infections are frequent complications among patients treated for cancer. The type, severity, and treatment of bacterial infections vary and depend upon the specific malignancy, associated chemotherapies, and transplantation. This chapter discusses commonly encountered bacterial pathogens as well as Nocardia and mycobacteria in patients with cancer and addresses the clinical syndromes and management. Drug-resistant bacteria are becoming an increasingly recognized problem in patients with cancer. Antimicrobial resistance in select gram-positive and gram-negative bacteria are discussed along with the mechanisms of resistance and recommended therapies. PMID:24706222
Wilson, John W
The Arabidopsis genome contains a large number of putative transcription factors, containing a DNA binding domain similar to APETALA2/ethylene response element binding protein (AP2/EREBP), for most of which a function is not known. Phylogenetic analysis divides the Apetala 2 (AP2) super-family into 5 major groups: AP2, RAV, ethylene response factor (ERF), dehydration response element binding protein (DREB) and At4g13040. Similar to ERF and DREB, the At4g13040 protein contains only one AP2 domain; however, its structural uniqueness places it into a distinct group. In this article, we report that At4g13040 (referred herein as Apetala 2 family protein involved in SA mediated disease defense 1 - APD1) is an important regulator for SA mediated plant defense. The APD1 gene is upregulated upon pathogen inoculation, exogenous SA application and in the mutant that constitutively activates SA signaling. The T-DNA insertion lines (inserted in the APD1 promoter), which fail to induce expression upon pathogen inoculation, are compromised for resistance against virulent bacterial pathogens and show reduced induction of pathogenesis related 1 gene. Our results suggest that APD1 functions downstream of PAD4 in Arabidopsis and promotes pathogen-induced SA accumulation. Exogenous SA application completely restores the loss-of-resistance phenotype of the apd1 mutant. Thus, APD1 is a positive regulator of disease defense that functions upstream of SA accumulation. PMID:24612849
Giri, Mrunmay Kumar; Swain, Swadhin; Gautam, Janesh Kumar; Singh, Subaran; Singh, Nidhi; Bhattacharjee, Lipika; Nandi, Ashis Kumar
The motility of organisms is often directed in response to environmental stimuli. Rheotaxis is the directed movement resulting from fluid velocity gradients, long studied in fish, aquatic invertebrates, and spermatozoa. Using carefully controlled microfluidic flows, we show that rheotaxis also occurs in bacteria. Excellent quantitative agreement between experiments with Bacillus subtilis and a mathematical model reveals that bacterial rheotaxis is a purely physical phenomenon, in contrast to fish rheotaxis but in the same way as sperm rheotaxis. This previously unrecognized bacterial taxis results from a subtle interplay between velocity gradients and the helical shape of flagella, which together generate a torque that alters a bacterium's swimming direction. Because this torque is independent of the presence of a nearby surface, bacterial rheotaxis is not limited to the immediate neighborhood of liquid–solid interfaces, but also takes place in the bulk fluid. We predict that rheotaxis occurs in a wide range of bacterial habitats, from the natural environment to the human body, and can interfere with chemotaxis, suggesting that the fitness benefit conferred by bacterial motility may be sharply reduced in some hydrodynamic conditions.
Marcos; Fu, Henry C.; Powers, Thomas R.; Stocker, Roman
ABSTRACT The Escherichia coli membrane protein DsbD functions as an electron hub that dispatches electrons received from the cytoplasmic thioredoxin system to periplasmic oxidoreductases involved in protein disulfide isomerization, cytochrome c biogenesis, and sulfenic acid reduction. Here, we describe a new class of DsbD proteins, named ScsB, whose members are found in proteobacteria and Chlamydia. ScsB has a domain organization similar to that of DsbD, but its amino-terminal domain differs significantly. In DsbD, this domain directly interacts with substrates to reduce them, which suggests that ScsB acts on a different array of substrates. Using Caulobacter crescentus as a model organism, we searched for the substrates of ScsB. We discovered that ScsB provides electrons to the first peroxide reduction pathway identified in the bacterial cell envelope. The reduction pathway comprises a thioredoxin-like protein, TlpA, and a peroxiredoxin, PprX. We show that PprX is a thiol-dependent peroxidase that efficiently reduces both hydrogen peroxide and organic peroxides. Moreover, we identified two additional proteins that depend on ScsB for reduction, a peroxiredoxin-like protein, PrxL, and a novel protein disulfide isomerase, ScsC. Altogether, our results reveal that the array of proteins involved in reductive pathways in the oxidative cell envelope is significantly broader than was previously thought. Moreover, the identification of a new periplasmic peroxiredoxin indicates that in some bacteria, it is important to directly scavenge peroxides in the cell envelope even before they reach the cytoplasm.
Cho, Seung-Hyun; Parsonage, Derek; Thurston, Casey; Dutton, Rachel J.; Poole, Leslie B.; Collet, Jean-Francois; Beckwith, Jon
Acropora white syndrome (AWS) is characterized by rapid tissue loss revealing the white underlying skeleton and affects corals worldwide; however, reports of causal agents are conflicting. Samples were collected from healthy and diseased corals and seawater around American Samoa and bacteria associated with AWS characterized using both culture-dependent and culture-independent methods, from coral mucus and tissue slurries, respectively. Bacterial 16S rRNA gene clone libraries derived from coral tissue were dominated by the Gammaproteobacteria, and Jaccard's distances calculated between the clone libraries showed that those from diseased corals were more similar to each other than to those from healthy corals. 16S rRNA genes from 78 culturable coral mucus isolates also revealed a distinct partitioning of bacterial genera into healthy and diseased corals. Isolates identified as Vibrionaceae were further characterized by multilocus sequence typing, revealing that whilst several Vibrio spp. were found to be associated with AWS lesions, a recently described species, Vibrio owensii, was prevalent amongst cultured Vibrio isolates. Unaffected tissues from corals with AWS had a different microbiota than normal Acropora as found by others. Determining whether a microbial shift occurs prior to disease outbreaks will be a useful avenue of pursuit and could be helpful in detecting prodromal signs of coral disease prior to manifestation of lesions. PMID:22283330
Wilson, Bryan; Aeby, Greta S; Work, Thierry M; Bourne, David G
Many bacteria and fungi can enhance plant growth. The present review is limited to plant growth promoting rhizobacteria (PGPR). However, it includes endophytic bacteria that show plant growth enhancing activity as well. Also the best studied bacterial mechanisms of plant growth promotion are discussed, with a special emphasis on biological nitrogen fixation and synthesis of phytohormones, including less understood mechanisms
LUIS E. FUENTES-RAMIREZ; Jesus Caballero-Mellado
Bacterial vaginosis is the commonest cause of abnormal vaginal discharge in women of childbearing age, with a prevalence as high as 50% in some communities. The symptoms of discharge and offensive smell can cause considerable distress, although 50% of women are asymptomatic when diagnosed. Microbiologically the usually dominant lactobacillus flora is overwhelmed by an overgrowth of predominantly anaerobic organisms, accompanied
Crystal structure of methylenetetrahydromethanopterin reductase (Mer) in complex with coenzyme F420: Architecture of the F420/FMN binding site of enzymes within the nonprolyl cis-peptide containing bacterial luciferase family
Methylenetetratetrahydromethanopterin reductase (Mer) is involved in CO2 reduction to methane in methanogenic archaea and catalyses the reversible reduction of methylenetetrahydromethanopterin (methylene-H4MPT) to methyl-H4MPT with coenzyme F420H2, which is a reduced 5?-deazaflavin. Mer was recently established as a TIM barrel structure containing a nonprolyl cis-peptide bond but the binding site of the substrates remained elusive. We report here on the crystal structure of Mer in complex with F420 at 2.6 Ĺ resolution. The isoalloxazine ring is present in a pronounced butterfly conformation, being induced from the Re-face of F420 by a bulge that contains the non-prolyl cis-peptide bond. The bindingmode of F420 is very similar to that in F420-dependent alcohol dehydrogenase Adf despite the low sequence identity of 21%. Moreover, binding of F420 to the apoenzyme was only associated with minor conformational changes of the polypeptide chain. These findings allowed us to build an improved model of FMN into its binding site in bacterial luciferase, which belongs to the same structural family as Mer and Adf and also contains a nonprolyl cis-peptide bond in an equivalent position.
Aufhammer, Stephan W.; Warkentin, Eberhard; Ermler, Ulrich; Hagemeier, Christoph H.; Thauer, Rudolf K.; Shima, Seigo
Bacterial microcompartments (BMCs) are organelles composed entirely of protein. They promote specific metabolic processes by encapsulating and colocalizing enzymes with their substrates and cofactors, by protecting vulnerable enzymes in a defined microenvironment, and by sequestering toxic or volatile intermediates. Prototypes of the BMCs are the carboxysomes of autotrophic bacteria. However, structures of similar polyhedral shape are being discovered in an ever-increasing number of heterotrophic bacteria, where they participate in the utilization of specialty carbon and energy sources. Comparative genomics reveals that the potential for this type of compartmentalization is widespread across bacterial phyla and suggests that genetic modules encoding BMCs are frequently laterally transferred among bacteria. The diverse functions of these BMCs suggest that they contribute to metabolic innovation in bacteria in a broad range of environments. PMID:20825353
Kerfeld, Cheryl A; Heinhorst, Sabine; Cannon, Gordon C
Cell shape is not the product of a particular gene or protein, but the result of the collective actions of many of them. These\\u000a are involved in several processes, including peptidoglycan precursor synthesis, peptidoglycan synthesis and recycling, cell\\u000a elongation, cell septation and division site selection. The analysis of the “morphogene” content of several bacterial genomes\\u000a suggests that there are three
Jesús Mingorance; Anabel Rico; Paulino GÓmez-Puertas
Sensing their environment is a crucial ability of all life forms. In higher eukaryotes the sensing of airborne volatile compounds, or olfaction, is well developed. In plants, slime moulds and yeast there is also compelling evidence that these organisms can smell their environment and respond accordingly. Here we show that bacteria are also capable of olfaction. Bacillus licheniformis was able to sense airborne volatile metabolites produced by neighbouring bacterial cultures and cells could respond to this chemical information in a coordinated way. When Bacillus licheniformis was grown in a microtitre plate adjacent to a bacterial culture of the same or a different species, growing in complex medium, biofilm formation and pigment production were elicited by volatile molecules. A weaker response occurred in increasingly distant wells. The emitted volatile molecule was identified as ammonia. These data demonstrate that B. licheniformis has evolved the ability collect information about its environment from the surrounding air and physiologically respond to it in a manner similar to olfaction. This is the first time that a behavioural response triggered by odorant molecules received through the gas phase is described in bacteria. PMID:20721987
Nijland, Reindert; Burgess, J Grant
Knock-out of SO1377 gene, which encodes the member of a conserved hypothetical bacterial protein family COG2268, results in alteration of iron metabolism, increased spontaneous mutation and hydrogen peroxide sensitivity in Shewanella oneidensis MR-1
Background Shewanella oneidensis MR-1 is a facultative, gram-negative bacterium capable of coupling the oxidation of organic carbon to a wide range of electron acceptors such as oxygen, nitrate and metals, and has potential for bioremediation of heavy metal contaminated sites. The complete 5-Mb genome of S. oneidensis MR-1 was sequenced and standard sequence-comparison methods revealed approximately 42% of the MR-1 genome encodes proteins of unknown function. Defining the functions of hypothetical proteins is a great challenge and may need a systems approach. In this study, by using integrated approaches including whole genomic microarray and proteomics, we examined knockout effects of the gene encoding SO1377 (gi24372955), a member of the conserved, hypothetical, bacterial protein family COG2268 (Clusters of Orthologous Group) in bacterium Shewanella oneidensis MR-1, under various physiological conditions. Results Compared with the wild-type strain, growth assays showed that the deletion mutant had a decreased growth rate when cultured aerobically, but not affected under anaerobic conditions. Whole-genome expression (RNA and protein) profiles revealed numerous gene and protein expression changes relative to the wild-type control, including some involved in iron metabolism, oxidative damage protection and respiratory electron transfer, e. g. complex IV of the respiration chain. Although total intracellular iron levels remained unchanged, whole-cell electron paramagnetic resonance (EPR) demonstrated that the level of free iron in mutant cells was 3 times less than that of the wild-type strain. Siderophore excretion in the mutant also decreased in iron-depleted medium. The mutant was more sensitive to hydrogen peroxide and gave rise to 100 times more colonies resistant to gentamicin or kanamycin. Conclusion Our results showed that the knock-out of SO1377 gene had pleiotropic effects and suggested that SO1377 may play a role in iron homeostasis and oxidative damage protection in S. oneidensis MR-1.
Gao, Weimin; Liu, Yongqing; Giometti, Carol S; Tollaksen, Sandra L; Khare, Tripti; Wu, Liyou; Klingeman, Dawn M; Fields, Matthew W; Zhou, Jizhong
The study of bacterial symbionts of eukaryotic hosts has become a powerful discovery engine for chemistry. This highlight looks at four case studies that exemplify the range of chemistry and biology involved in these symbioses: a bacterial symbiont of a fungus and a marine invertebrate that produce compounds with significant anticancer activity, and bacterial symbionts of insects and nematodes that produce compounds that regulate multilateral symbioses. In the last ten years, a series of shocking revelations – the molecular equivalents of a reality TV show’s uncovering the true parents of a well known individual or a deeply hidden family secret – altered the study of genetically encoded small molecules, natural products for short. These revelations all involved natural products produced by bacterial symbionts, and while details differed, two main plot lines emerged: parentage, in which the real producers of well known natural products with medical potential were not the organisms from which they were originally discovered, and hidden relationships, in which bacterially produced small molecules turned out to be the unsuspected regulators of complex interactions. For chemists, these studies led to new molecules, new biosynthetic pathways, and an understanding of the biological functions these molecules fulfill.
Crawford, Jason M.; Clardy, Jon
Small molecular weight GTPases are master regulators of eukaryotic signalling, making them prime targets for bacterial virulence factors. Here, we review the recent advances made in understanding how bacterial type III secreted effector proteins directly activate GTPase signalling cascades. Specifically we focus on the SopE/WxxxE family of effectors that functionally mimic guanine nucleotide exchange factors (GEFs): the endogenous activators of Rho-family GTPases. Recent structural and biochemical studies have provided keen insight into both the signalling potency and substrate specificity of bacterial GEFs. Additionally, these bacterial GEFs display fascinating cell biological properties that provide insight into both host cell physiology and infectious disease strategies. PMID:21951829
Orchard, Robert C; Alto, Neal M
Bacterial vaginosis (BV) is the most common of the vaginitides affecting women of reproductive age. It appears to be due to an alteration in the vaginal ecology by which Lactobacillus spp., the predominant organisms in the healthy vagina, are replaced by a mixed flora including Prevotella bivia, Prevotella disiens, Porphyromonas spp., Mobiluncus spp., and Peptostreptococcus spp. All of these organisms except Mobiluncus spp. are also members of the endogenous vaginal flora. While evidence from treatment trials does not support the notion that BV is sexually transmitted, recent studies have shown an increased risk associated with multiple sexual partners. It has also been suggested that the pathogenesis of BV may be similar to that of urinary tract infections, with the rectum serving as a reservoir for some BV-associated flora. The organisms associated with BV have also been recognized as agents of female upper genital tract infection, including pelvic inflammatory disease, and the syndrome BV has been associated with adverse outcome of pregnancy, including premature rupture of membranes, chorioamnionitis, and fetal loss; postpartum endometritis; cuff cellulitis; and urinary tract infections. The mechanisms by which the BV-associated flora causes the signs of BV are not well understood, but a role for H2O2-producing Lactobacillus spp. in protecting against colonization by catalase-negative anaerobic bacteria has been recognized. These and other aspects of BV are reviewed.
Spiegel, C A
Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. So there was a need to develop an inherent biomaterial, a self-repairing material which can remediate the cracks and fissures in concrete. Bacterial concrete is a material, which can successfully remediate cracks in concrete. This technique is highly desirable because the mineral precipitation induced as a result of microbial activities is pollution free and natural. As the cell wall of bacteria is anionic, metal accumulation (calcite) on the surface of the wall is substantial, thus the entire cell becomes crystalline and they eventually plug the pores and cracks in concrete. This paper discusses the plugging of artificially cracked cement mortar using Bacillus Pasteurii and Sporosarcina bacteria combined with sand as a filling material in artificially made cuts in cement mortar which was cured in urea and CaCl2 medium. The effect on the compressive strength and stiffness of the cement mortar cubes due to the mixing of bacteria is also discussed in this paper. It was found that use of bacteria improves the stiffness and compressive strength of concrete. Scanning electron microscope (SEM) is used to document the role of bacteria in microbiologically induced mineral precipitation. Rod like impressions were found on the face of calcite crystals indicating the presence of bacteria in those places. Energy- dispersive X-ray (EDX) spectra of the microbial precipitation on the surface of the crack indicated the abundance of calcium and the precipitation was inferred to be calcite (CaCO3).
Ramakrishnan, Venkataswamy; Ramesh, K. P.; Bang, S. S.
With the growing number of completely sequenced bacterial genes, accurate gene prediction in bacterial genomes remains an important problem. Although the existing tools predict genes in bacterial genomes with high overall accuracy, their ability to pinpoint the translation start site remains unsatisfactory. In this paper, we present a novel approach to bacterial start site prediction that takes into account multiple
Sridhar S. Hannenhalli; William S. Hayes; Artemis G. Hatzigeorgiou; James W. Fickett
Asparaginases and glutaminases are enzymes that catalyze the hydrolysis of asparagine or glutamine to the cor- respondent acid and ammonia. Based on their biochemical properties and sequence homology, this group of proteins, common to various organisms, can be divided into three families: bacterial asparaginases, plant asparaginases and en- zymes similar to Rhizobium etli asparaginase. Bacterial L-asparaginases can be further subdivided
Mario Sanches; Sandra Krauchenco; Igor Polikarpov
newsletter | contact Share | Nail Infection, Bacterial (Paronychia) Information for adults A A A Nail-fold swelling and large pus-filled lesions are typical ... bacterial paronychia. Overview Paronychia, commonly known as bacterial nail infection, is inflammation of the region of the ...
Members of Florence Kaslow's family of procreation share their insights into the myriad ways in which her professional contributions in family psychology and international psychology have had an impact on their family life. Particular attention is paid to the family life of psychotherapists, healthy family functioning, healthy long-term marriages, sex therapy, military psychology, family business consulting and the use of
Nadine J. Kaslow; Solis Kaslow; Howard I. Kaslow
Implicit in the central dogma is the hypothesis that each protein gene product has but one function. However, over the past decade, it has become clear that many proteins have one or more unique functions, over-and-above the principal biological action of the specific protein. This phenomenon is now known as protein moonlighting and many well-known proteins such as metabolic enzymes and molecular chaperones are now recognised as moonlighting proteins. A growing number of bacterial species are being found to have moonlighting proteins and the moonlighting activities of such proteins can contribute to bacterial virulence behaviour. The glycolytic enzymes, glyceraldehyde-3-phosphate dehydrogenase (GAPD) and enolase, and the cell stress proteins: chaperonin 60, Hsp70 and peptidyl prolyl isomerase, are among the most common of the bacterial moonlighting proteins which play a role in bacterial virulence. Moonlighting activities include adhesion and modulation of cell signalling processes. It is likely that only the tip of the bacterial moonlighting iceberg has been sighted and the next decade will bring with it many new discoveries of bacterial moonlighting proteins with a role in bacterial virulence. PMID:22143554
Henderson, Brian; Martin, Andrew
A member of the cathelicidin family of antimicrobial peptides is produced in the upper airway of the chinchilla and its mRNA expression is altered by common viral and bacterial co-pathogens of otitis media
Cationic antimicrobial peptides (AMPs), a component of the innate immune system, play a major role in defense of mucosal surfaces against a wide spectrum of microorganisms such as viral and bacterial co-pathogens of the polymicrobial disease otitis media (OM). To further understand the role of AMPs in OM, we cloned a cDNA encoding a cathelicidin homolog (cCRAMP) from upper respiratory tract (URT) mucosae of the chinchilla, the predominant host used to model experimental OM. Recombinant cCRAMP exhibited alpha-helical secondary structure and killed the three main bacterial pathogens of OM. In situ hybridization showed cCRAMP mRNA production in epithelium of the chinchilla Eustachian tube and RT-PCR was used to amplify cCRAMP mRNA from several other tissues of the chinchilla URT. Quantitative RT-PCR analysis of chinchilla middle ear epithelial cells (CMEEs) incubated with either viral (influenza A virus, adenovirus, or RSV) or bacterial (nontypeable H. influenzae, M. catarrhalis, or S. pneumoniae) pathogens associated with OM demonstrated distinct microbe-specific patterns of altered expression. Collectively, these data showed that viruses and bacteria modulate AMP messages in the URT, which likely contributes to the disease course of OM.
McGillivary, Glen; Ray, William C.; Bevins, Charles L.; Munson, Robert S.; Bakaletz, Lauren O.
The taxonomic composition and distribution of microorganisms differing in the degree of association with the intestinal mucosa\\u000a of the pike (Esox lucius) has been studied. Microorgansism of the families Enterobacteriaceae, Aeromonadaceae, and Vibrionaceae dominate in the gut\\u000a microflora. Numerically prevailing bacterial species are characterized by high proteolytic and amylolytic enzyme activities\\u000a as well as by high persistence accounted for by
G. I. Izvekova; N. V. Nemtseva; A. O. Plotnikov
Viruses are hypothesized to maintain diversity in microbial assemblages by regulating the abundance of dominant competitors and thereby allowing less-dominant competitors to persist in assemblages; however, there have been few empirical data sets to support this idea. In this study, we examined the relationship between the ratio of viral abundance to bacterial abundance, viral production, and the relative richness and diversity of bacterial assemblage fingerprints, in samples taken from geographically widespread locations (North Pacific gyre, the Amazon River plume and adjacent North Atlantic gyre, Gulf of Mexico, Southern California Bight and Arafura—Coral Seas) which are oligo- to mesotrophic. Bacterial assemblage richness and diversity as measured by automated rRNA intergenic spacer (ARISA) fingerprinting were significantly and positively correlated with the ratio of virus abundance to bacteria abundance (VBR) and to the rate of virus production only in the oligotrophic North Pacific gyre. ARISA fingerprint richness/diversity were not significantly correlated to viral parameters when assessed across all samples in surface waters, suggesting there is not a singular global quantitative relationship between viral pressure and host diversity within well evolved host/virus systems in different geographic locations in plankton. In sediments off Southern California, viral parameters significantly and negatively correlated with ARISA diversity, suggesting strong viral interactions in this habitat. To examine covariation of viral parameters and the relative abundance and diversity of rarer bacterial taxa (i.e., less-dominant competitor), the richness and diversity of diazotroph communities was measured using terminal restriction fragment length polymorphism (TRFLP) of a portion ( nifH) of the nitrogenase gene. The richness and diversity of diazotrophic communities were significantly and negatively correlated with viral parameters across all locations. Since diazotrophs include many opportunistic taxa (e.g. Vibrionaceae), and because these bacteria may be more susceptible to viral attack due to enhanced resource uptake abilities and potentially rapid localized growth, it is possible that this negative effect was due to enhanced viral lysis. Consequently, virus infection may have positive effects upon bacterioplankton diversity in the oligotrophic ocean, by regulating the abundance of dominant competitors, and allowing rarer taxa to coexist; however, some rarer taxa (such as diazotrophs) may be more susceptible to viral attack due to opportunistic lifestyles.
Hewson, Ian; Fuhrman, Jed A.
Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyze recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice.
Olivares, Jorge; Bernardini, Alejandra; Garcia-Leon, Guillermo; Corona, Fernando; B. Sanchez, Maria; Martinez, Jose L.
This work aimed at evaluating the biodegradability of different bacterial surfactants in liquid medium and in soil microcosms.\\u000a The biodegradability of biosurfactants by pure and mixed bacterial cultures was evaluated through CO2 evolution. Three bacterial strains, Acinetobacter baumanni LBBMA ES11, Acinetobacter haemolyticus LBBMA 53 and Pseudomonas sp. LBBMA 101B, used the biosurfactants produced by Bacillus sp. LBBMA 111A (mixed lipopeptide),
Tânia M. S. Lima; Lorena C. Procópio; Felipe D. Brandăo; André M. X. Carvalho; Marcos R. Tótola; Arnaldo C. Borges
... Families & Friendships Military Sexual Trauma Depression mild Traumatic Brain Injury Life Stress Health & Wellness Anger Stigma Suicide Prevention ... Post-Traumatic Stress Sleep Alcohol & Drugs mild Traumatic Brain Injury Resilience Families with Kids Depression Families & Friendships Tobacco ...
We used a polyphasic approach for precise identification of bacterial flora (Vibrionaceae) isolated from crown-of-thorns starfish (COTS) from Lizard Island (Great Barrier Reef, Australia) and Guam (U.S.A., Western Pacific Ocean). Previous 16S rRNA gene phylogenetic analysis was useful to allocate and identify isolates within the Photobacterium, Splendidus and Harveyi clades but failed in the identification of Vibrio harveyi-like isolates. Species of the V harveyi group have almost indistinguishable phenotypes and genotypes, and thus, identification by standard biochemical tests and 16S rRNA gene analysis is commonly inaccurate. Biochemical profiling and sequence analysis of additional topA and mreB housekeeping genes were carried out for definitive identification of 19 bacterial isolates recovered from sick and wild COTS. For 8 isolates, biochemical profiles and topA and mreB gene sequence alignments with the closest relatives (GenBank) confirmed previous 16S rRNA-based identification: V. fortis and Photobacterium eurosenbergii species (from wild COTS), and V natriegens (from diseased COTS). Further phylogenetic analysis based on topA and mreB concatenated sequences served to identify the remaining 11 V harveyi-like isolates: V. owensii and V. rotiferianus (from wild COTS), and V. owensii, V. rotiferianus, and V. harveyi (from diseased COTS). This study further confirms the reliability of topA-mreB gene sequence analysis for identification of these close species, and it reveals a wider distribution range of the potentially pathogenic V. harveyi group. PMID:22013751
Rivera-Posada, J A; Pratchett, M; Cano-Gomez, A; Arango-Gomez, J D; Owens, L
Comparison of family functioning in 103 neglectful and 102 nonneglectful low-income families found that neglectful mothers reported their families as having more family conflict and less expression of feelings, but not less cohesiveness. Observational measures indicated neglectful families were less organized, more chaotic, and less verbally…
Gaudin, James M., Jr.; And Others
Describes an effective laboratory method for demonstrating bacterial flagella that utilizes the Proteus mirabilis organism and a special harvesting technique. Includes safety considerations for the laboratory exercise. (MDH)
Porter, John R.; And Others
Small intestinal bacterial overgrowth (SIBO) syndrome is characterized in its florid form by diarrhoea and weight loss. The most common underlying factors are dysmotility, small intestinal obstruction, blind or afferent loops. Small intestinal bacterial overgrowth can be diagnosed by: 1) culture of jejunum aspirate for bacterial counts, 2) 14C-D-xylose breath testing, 3) non-invasive hydrogen breath testing using glucose or lactulose or 4) 14C-glycocholic acid breath testing. The treatment usually consists of the eradication of bacterial overgrowth with repeated course of antimicrobials, correction of associated nutritional deficiencies and, when possible, correction of the underlying predisposing conditions. PMID:18609165
Rana, S V; Bhardwaj, S B
Seven completed suicides in a family of lower socioeconomic status and suburban domicile in Pondicherry are reported. The presence of bipolar affective disorder in the family members and the absence of exogenous factors are illustrated by utilising both family history method and family study method. The details collected formed the basis for the terminology ‘familial suicide’. The management of the index case, one of the only three surviving male members of the family, who presented with suicidal ruminations and depressive features, is described.
Unni, K.E. Sadanaandan
Over the years it has been important for humans to control the populations of harmful insects and insecticides have been used for this purpose in agricultural and horticultural sectors. Synthetic insecticides, owing to their various side effects, have been widely replaced by biological insecticides. In this review we attempt to describe three bacterial species that are known to produce insecticidal toxins of tremendous biotechnological, agricultural, and economic importance. Bacillus thuringiensis (BT) accounts for 90% of the bioinsecticide market and it produces insecticidal toxins referred to as delta endotoxins. The other two bacteria belong to the genera Photorhabdus and Xenorhabdus, which are symbiotically associated with entomopathogenic nematodes of the families Heterorhabditidae and Steinernematidae respectively. Whereas, Xenorhabdus and Photorhabdus exist in a mutualistic association with the entomopathogenic nematodes, BT act alone. BT formulations are widely used in the field against insects; however, over the years there has been a gradual development of insect resistance against BT toxins. No resistance against Xenorhabdus or Photorhabdus has been reported to date. More recently BT transgenic crops have been prepared; however, there are growing concerns about the safety of these genetically modified crops. Nematodal formulations are also used in the field to curb harmful insect populations. Resistance development to entomopathogenic nematodes is unlikely due to the physical macroscopic nature of infection. Xenorhabdus and Photorhabdus transgenes have not yet been prepared; but are predicted to be available in the near future. In this review we start with an overview of the synthetic insecticides and then discuss Bacillus thuringiensis, Xenorhabdus nematophilus, and Photorhabdus luminescens in greater detail. PMID:15116762
Chattopadhyay, Abanti; Bhatnagar, N B; Bhatnagar, Rakesh
Bacterial infections occur when the natural host defenses are overwhelmed by invading bacteria. The main component of the host defense is impaired when neutrophil count or function is too low, putting the host at great risk of developing an acute infection. In people with intact immune systems, neutrophil count increases during bacterial infection. However, there are two important clinical cases
Roy Malka; Eliezer Shochat; Vered Rom-Kedar; Robert Planque
The introduction of Candida albicans into cefoperazone-treated mice results in changes in bacterial community reassembly. Our objective was to use high-throughput sequencing to characterize at much greater depth the specific changes in the bacterial microbiome. The colonization of C. albicans significantly altered bacterial community reassembly that was evident at multiple taxonomic levels of resolution. There were marked changes in the levels of Bacteriodetes and Lactobacillaceae. Lachnospiraceae and Ruminococcaceae, the two most abundant bacterial families, did not change in relative proportions after antibiotics, but there were marked genera-level shifts within these two bacterial families. The microbiome shifts occurred in the absence of overt intestinal inflammation. Overall, these experiments demonstrate that the introduction of a single new microbe in numerically inferior numbers into the bacterial microbiome during a broad community disturbance has the potential to significantly alter the subsequent reassembly of the bacterial community as it recovers from that disturbance.
Erb Downward, John R.; Falkowski, Nicole R.; Mason, Katie L.; Muraglia, Ryan; Huffnagle, Gary B.
From the third generation onwards, family firms could get into business threatening situations. This might depend on the growing number of owners, the increasing distance of family members from the firm, and the heterogeneity of their interests. Thus, agency prob- lems and negative conflicts might occur. This calls for the appropriate choice of family gov- ernance mechanisms. Family councils might
Klaus Brockhoff; Alexander Koeberle-Schmid
This review classifies and analyzes the literature data on bacterial autoinducers (AI), the signal molecules produced and\\u000a secreted by bacterial cells and responsible for intercellular communication (quorum sensing, QS). The most important families\\u000a of nonpeptide AI are discussed, including N-acyl homoserine lactones, derivatives of 2-methyl-2,3,4,5-tetrahydroxy tetrahydrofuran, indole and quinoline derivatives,\\u000a and adrenalinerelated compounds. The data is provided on the intracellular
A. O. Shpakov
The acronym IDEALS summarizes family physicians' obligations when violence is suspected: to identify family violence; document injuries; educate families and ensure safety for victims; access resources and coordinate care; co-operate in the legal process; and provide support for families. Failure to respond reflects personal and professional experience and attitudes, fear of legal involvement, and lack of knowledge. Risks of intervention include physician burnout, physician overfunctioning, escalation of violence, and family disruption.
Herbert, Carol P.
On hard agar gel, there is insufficient surface hydration for bacteria to swim or swarm. Instead, growth occurs in colonies of close-packed cells, which expand purely due to repulsive interactions: individual bacteria push each other out of the way through the force of their growth. In this way, bacterial colonies represent a new type of ``active'' granular matter. In this study, we investigate the physical, biochemical, and genetic elements that determine the static and dynamic aspects of this mode of bacterial growth for E. coli. We characterize the process of colony expansion empirically, and use discrete and continuum models to examine the extent to which our observations can be explained by the growth characteristics of non-communicating cells, coupled together by physical forces, nutrients, and waste products. Our results challenge the commonly accepted modes of bacterial colony growth and provide insight into sources of growth limitation in crowded bacterial communities.
Warren, Mya; Hwa, Terence
... Resources for Help and Information The One-Page Merck Manual of Health Medical Terms Conversion Tables Manuals ... Lymphangitis Necrotizing Skin Infections Staphylococcal Scalded Skin Syndrome Merck Manual > Patients & Caregivers > Skin Disorders > Bacterial Skin Infections ...
Bacterial glycoproteins represent an attractive target for new antibacterial treatments, as they are frequently linked to pathogenesis and contain distinctive glycans that are absent in humans. Despite their potential therapeutic importance, many bacterial glycoproteins remain uncharacterized. This review focuses on recent advances in deciphering the bacterial glycocode, including metabolic glycan labeling to discover and characterize bacterial glycoproteins, lectin-based microarrays to monitor bacterial glycoprotein dynamics, crosslinking sugars to assess the roles of bacterial glycoproteins, and harnessing bacterial glycosylation systems for the efficient production of industrially important glycoproteins.
Longwell, Scott A.; Dube, Danielle H.
Full Circle Programs is an organization providing family preservation and reunification services. Full Circle responds to families uniquely, rather than according to predetermined models. Medical testing, counseling, and practical assistance are provided. (BC)
Brown, Carolyn L.; Little, Susan
The Directive supersedes Secretary of Defense Memorandum, 'Department of Defense Family Policy,' establishes policies, assigns responsibilities, and prescribes procedures on family policy for Department of Defense (DoD) military personnel in Active, Natio...
The role, functions, and potential of family medicine are examined in a discussion drawing on observations of the University of Rochester Family Medicine Program at Highland Hospital, Rochester, New York. The discussion opens with a review of the factors ...
P. S. Warren
Bacterial infections occur when the natural host defenses are overwhelmed by invading bacteria. The main component of the host defense is impaired when neutrophil count or function is too low, putting the host at great risk of developing an acute infection. In people with intact immune systems, neutrophil count increases during bacterial infection. However, there are two important clinical cases in which they remain constant: a) in patients with neutropenic-associated conditions, such as those undergoing chemotherapy at the nadir (the minimum clinically observable neutrophil level); b) in ex vivo examination of the patient's neutrophil bactericidal activity. Here we study bacterial population dynamics under fixed neutrophil levels by mathematical modelling. We show that under reasonable biological assumptions, there are only two possible scenarios: 1) Bacterial behavior is monostable: it always converges to a stable equilibrium of bacterial concentration which only depends, in a gradual manner, on the neutrophil level (and not on the initial bacterial level). We call such a behavior type I dynamics. 2) The bacterial dynamics is bistable for some range of neutrophil levels. We call such a behavior type II dynamics. In the bistable case (type II), one equilibrium corresponds to a healthy state whereas the other corresponds to a fulminant bacterial infection. We demonstrate that published data of in vitro Staphylococcus epidermidis bactericidal experiments are inconsistent with both the type I dynamics and the commonly used linear model and are consistent with type II dynamics. We argue that type II dynamics is a plausible mechanism for the development of a fulminant infection.
Malka, Roy; Shochat, Eliezer; Rom-Kedar, Vered
This "Feature Issue" of the quarterly journal "Impact" presents 19 brief articles on family support systems in the United States for persons with developmental disabilities and their families. Emphasis is on provisions of Public Law 99-457. Articles include: "Family Support in the United States: Setting a Course for the 1990s" (James Knoll);…
Wieck, Colleen, Ed.; McBride, Marijo, Ed.
Another major force not letting us succeed in the treatment of diabetes remains right inside the patients home, their family members. Hence, it is important to know the perception of the close family members about this simple and strong tool in diabetes, 'insulin'. The drug is nearing its century, it has not fully being accepted gracefully even in todays electronic savvy society. So, we need to strongly discover the reason for its non-acceptance, while trials are out inventing new drugs. One vital thing that can change this attitude is increasing the understanding of this drug, insulin in depth to close people around the patient, the 'family'. Underestimating family's perception about disease and treatment for diabetes is detrimental to both diseased and the doctor. This consists of a biopsychosocial model; biological, psychological and social factors. Family forms the most important part of it. The strategies in family therapy include psychodynamic, structural, strategic, and cognitive-behavioral component. Diabetes has and will continue to rise, so will be the treatment options. From the clinicians side its to fix fasting first but from patients its fix family first. Family therapy demonstrates the importance of insulin initiation and maintenance in insulin naive patients, and continuation for others. The specific needs of such patients and their impact on family life are met with family therapy. Who needs family therapy? Benefits of family therapy and a case based approach is covered. PMID:24251191
The newsletter offers perspectives on the provision of family support services for families with disabled members. An introductory article by Madeleine Will, Assistant Secretary for Special Education and Rehabilitative Services, stresses the impressive coping skills exhibited by many such families and their relationship to service professionals.…
Focal Point, 1988
Another major force not letting us succeed in the treatment of diabetes remains right inside the patients home, their family members. Hence, it is important to know the perception of the close family members about this simple and strong tool in diabetes, ‘insulin’. The drug is nearing its century, it has not fully being accepted gracefully even in todays electronic savvy society. So, we need to strongly discover the reason for its non-acceptance, while trials are out inventing new drugs. One vital thing that can change this attitude is increasing the understanding of this drug, insulin in depth to close people around the patient, the ‘family’. Underestimating family's perception about disease and treatment for diabetes is detrimental to both diseased and the doctor. This consists of a biopsychosocial model; biological, psychological and social factors. Family forms the most important part of it. The strategies in family therapy include psychodynamic, structural, strategic, and cognitive-behavioral component. Diabetes has and will continue to rise, so will be the treatment options. From the clinicians side its to fix fasting first but from patients its fix family first. Family therapy demonstrates the importance of insulin initiation and maintenance in insulin naive patients, and continuation for others. The specific needs of such patients and their impact on family life are met with family therapy. Who needs family therapy? Benefits of family therapy and a case based approach is covered.
The association between urticaria and infectious diseases has been discussed for >100 years. However, a causal relationship with underlying or precipitating infection is difficult to establish. The purpose of this work was to perform a systematic analysis of the published cases of urticaria associated with bacterial infections. We give an umbrella breakdown of up-to-date systematic reviews and other important publications on the complex association of urticaria and bacterial infections. We did a Medline search, for English language articles published until January 2014, using the key words "urticaria" and "bacteria/bacterial disease"; a second analysis was performed in groups of bacteria and using each germ name as a key word. Many bacterial infections have been associated with urticaria manifestation, such as Helicobacter pylori, Streptococcus, Staphylococcus, Mycoplasma pneumonia, Salmonella, Brucella, Mycobacterium leprae, Borrelia, Chlamydia pneumonia, and Yersinia enterocolitica. In some cases the skin manifestations, described as urticaria, could be caused by the presence of the microorganism in the skin, or for the action of their toxins, or to the complement activation mediated by circulating immune complexes. Although only a weak association with urticaria of unclear pathogenesis exists, clinicians should consider these bacterial agents in the workup of the patients with urticaria. The eradication of the infection could, in fact, lead to the resolution of urticaria. Prospective studies and well-structured research are obviously needed to better clarify the real role of bacteria in the pathogenesis of urticaria and their relative prevalence. PMID:24857191
Minciullo, Paola L; Cascio, Antonio; Barberi, Giuseppina; Gangemi, Sebastiano
This work aimed at evaluating the biodegradability of different bacterial surfactants in liquid medium and in soil microcosms. The biodegradability of biosurfactants by pure and mixed bacterial cultures was evaluated through CO(2) evolution. Three bacterial strains, Acinetobacter baumanni LBBMA ES11, Acinetobacter haemolyticus LBBMA 53 and Pseudomonas sp. LBBMA 101B, used the biosurfactants produced by Bacillus sp. LBBMA 111A (mixed lipopeptide), Bacillus subtilis LBBMA 155 (lipopeptide), Flavobacterium sp. LBBMA 168 (mixture of flavolipids), Dietzia Maris LBBMA 191(glycolipid) and Arthrobacter oxydans LBBMA 201(lipopeptide) as carbon sources in minimal medium. The synthetic surfactant sodium dodecyl sulfate (SDS) was also mineralized by these microorganisms, but at a lower rate. CO(2) emitted by a mixed bacterial culture in soil microcosms with biosurfactants was higher than in the microcosm containing SDS. Biosurfactant mineralization in soil was confirmed by the increase in surface tension of the soil aqueous extracts after incubation with the mixed bacterial culture. It can be concluded that, in terms of biodegradability and environmental security, these compounds are more suitable for applications in remediation technologies in comparison to synthetic surfactants. However, more information is needed on structure of biosurfactants, their interaction with soil and contaminants and scale up and cost for biosurfactant production. PMID:21053055
Lima, Tânia M S; Procópio, Lorena C; Brandăo, Felipe D; Carvalho, André M X; Tótola, Marcos R; Borges, Arnaldo C
Background There is a large amount of inconsistency in gene structure annotations of bacterial strains. This inconsistency is a frustrating impedance to effective comparative genomic analysis of bacterial strains in promising applications such as gaining insights into bacterial drug resistance. Results Here, we propose CAMBer as an approach to support comparative analysis of multiple bacterial strains. CAMBer produces what we called multigene families. Each multigene family reveals genes that are in one-to-one correspondence in the bacterial strains, thereby permitting their annotations to be integrated. We present results of our method applied to three human pathogens: Escherichia coli, Mycobacterium tuberculosis and Staphylococcus aureus. Conclusions As a result, more accurate and more comprehensive annotations of the bacterial strains can be produced.
The regulation of 2-hydroxybiphenyl and 2,2?-dihydroxybiphenyl degradation in Pseudomonas azelaica is mediated by the regulatory gene, hbpR. The hbpR gene encodes a 63-kDa protein belonging to the NtrC family of prokaryotic transcriptional activators and having the highest homology to members of the XylR/DmpR subclass. Disruption of the hbpR gene in P. azelaica and complementation in trans showed that the HbpR protein was the key regulator for 2-hydroxybiphenyl metabolism. Induction experiments with P. azelaica and Escherichia coli containing luxAB-based transcriptional fusions revealed that HbpR activates transcription from a promoter (PhbpC) in front of the first gene for 2-hydroxybiphenyl degradation, hbpC, and that 2-hydroxybiphenyl itself is the direct effector for HbpR-mediated activation. Of several compounds tested, only the pathway substrates 2-hydroxybiphenyl and 2,2?-dihydroxybiphenyl and structural analogs like 2-aminobiphenyl and 2-hydroxybiphenylmethane were effectors for HbpR activation. HbpR is therefore, to our knowledge, the first regulator of the XylR/DmpR class that recognizes biaromatic but not monoaromatic structures. Analysis of a spontaneously occurring mutant, P. azelaica HBP1 Prp, which can grow with the non-wild-type effector 2-propylphenol, revealed a single mutation in the hbpR gene (T613C) leading to a Trp?Arg substitution at amino acid residue 205. P. azelaica HBP1 derivative strains without a functional hbpR gene constitutively expressed the genes for 2-hydroxybiphenyl degradation when complemented in trans with the hbpR-T613C gene. This suggests the importance of this residue, which is conserved among all members of the XylR/DmpR subclass, for interdomain repression.
Jaspers, Marco C. M.; Suske, Winfried A.; Schmid, Andreas; Goslings, David A. M.; Kohler, Hans-Peter E.; van der Meer, Jan Roelof
Bacterial vaginosis is a common, complex clinical syndrome characterized by alterations in the normal vaginal flora. When symptomatic, it is associated with a malodorous vaginal discharge and on occasion vaginal burning or itching. Under normal conditions, lactobacilli constitute 95% of the bacteria in the vagina. Bacterial vaginosis is associated with severe reduction or absence of the normal H2O2-producing lactobacilli and overgrowth of anaerobic bacteria and Gardnerella vaginalis, Atopobium vaginae, Mycoplasma hominis and Mobiluncus species. Most types of infectious disease are diagnosed by culture, by isolating an antigen or RNA/DNA from the microbe, or by serodiagnosis to determine the presence of antibodies to the microbe. Therefore, demonstration of the presence of an infectious agent is often a necessary criterion for the diagnosis of the disease. This is not the case for bacterial vaginosis, since the ultimate cause of the disease is not yet known. There are a variety of methods for the diagnosis of bacterial vaginosis but no method can at present be regarded as the best. Diagnosing bacterial vaginosis has long been based on the clinical criteria of Amsel, whereby three of four defined criteria must be satisfied. Nugent's scoring system has been further developed and includes validation of the categories of observable bacteria structures. Up-to-date molecular tests are introduced, and better understanding of vaginal microbiome, a clear definition for bacterial vaginosis, and short-term and long-term fluctuations in vaginal microflora will help to better define molecular tests within the broader clinical context. PMID:24073569
Familial homozygous hypercholesterolemia is a rare autosomal disorder characterized by high levels of cholesterol, extensive tendon xanthomatosis and premature development of atherosclerotic disease. Early coronary artery disease with myocardial infarctions and sudden deaths are common. We reported a family of familial hypercholesterolemia from the Kashmir valley of the Indian subcontinent. The appearance and the severity of the cutaneous xanthomas was found to be age related suggesting a role for the duration of hypercholesterolemia in the development of xanthomatosis. PMID:17457492
Koul, Parvaiz A; Jan, Rafi A; Wahid, Abdul B; Bhat, Tariq A; Mudassir, Syed M
Type III secretion systems of Gram-negative bacteria are specific export machineries for virulence factors which allow their translocation to eukaryotic cells. Since they correlate with bacterial pathogenicity, their presence is used as a general indicator of bacterial virulence. By comparing the genetic relationship of the major type III secretion systems we found the family of genes encoding the inner-membrane channel
Katja Stuber; Joachim Frey; André P Burnens; Peter Kuhnert
Background In eukaryotes, PPP (protein phosphatase P) family is one of the two known protein phosphatase families specific for Ser and Thr. The role of PPP phosphatases in multiple signaling pathways in eukaryotic cell has been extensively studied. Unlike eukaryotic PPP phosphatases, bacterial members of the family have broad substrate specificity or may even be Tyr-specific. Moreover, one group of bacterial PPPs are diadenosine tetraphosphatases, indicating that bacterial PPP phosphatases may not necessarily function as protein phosphatases. Results We describe the presence in eukaryotes of three groups of expressed genes encoding "non-conventional" phosphatases of the PPP family. These enzymes are more closely related to bacterial PPP phosphatases than to the known eukaryotic members of the family. One group, found exclusively in land plants, is most closely related to PPP phosphatases from some ?-Proteobacteria, including Rhizobiales, Rhodobacterales and Rhodospirillaceae. This group is therefore termed Rhizobiales / Rhodobacterales / Rhodospirillaceae-like phosphatases, or Rhilphs. Phosphatases of the other group are found in Viridiplantae, Rhodophyta, Trypanosomatidae, Plasmodium and some fungi. They are structurally related to phosphatases from psychrophilic bacteria Shewanella and Colwellia, and are termed Shewanella-like phosphatases, or Shelphs. Phosphatases of the third group are distantly related to ApaH, bacterial diadenosine tetraphosphatases, and are termed ApaH-like phosphatases, or Alphs. Patchy distribution of Alphs in animals, plants, fungi, diatoms and kinetoplasts suggests that these phosphatases were present in the common ancestor of eukaryotes but were independently lost in many lineages. Rhilphs, Shelphs and Alphs form PPP clades, as divergent from "conventional" eukaryotic PPP phosphatases as they are from each other and from major bacterial clades. In addition, comparison of primary structures revealed a previously unrecognised (I/L/V)D(S/T)G motif, conserved in all bacterial and "bacterial-like" eukaryotic PPPs, but not in "conventional" eukaryotic and archaeal PPPs. Conclusions Our findings demonstrate that many eukaryotes possess diverse "bacterial-like" PPP phosphatases, the enzymatic characteristics, physiological roles and precise evolutionary history of which have yet to be determined.
Andreeva, Alexandra V; Kutuzov, Mikhail A
Background The SOS response is a well-known regulatory network present in most bacteria and aimed at addressing DNA damage. It has also been linked extensively to stress-induced mutagenesis, virulence and the emergence and dissemination of antibiotic resistance determinants. Recently, the SOS response has been shown to regulate the activity of integrases in the chromosomal superintegrons of the Vibrionaceae, which encompasses a wide range of pathogenic species harboring multiple chromosomes. Here we combine in silico and in vitro techniques to perform a comparative genomics analysis of the SOS regulon in the Vibrionaceae, and we extend the methodology to map this transcriptional network in other bacterial species harboring multiple chromosomes. Results Our analysis provides the first comprehensive description of the SOS response in a family (Vibrionaceae) that includes major human pathogens. It also identifies several previously unreported members of the SOS transcriptional network, including two proteins of unknown function. The analysis of the SOS response in other bacterial species with multiple chromosomes uncovers additional regulon members and reveals that there is a conserved core of SOS genes, and that specialized additions to this basic network take place in different phylogenetic groups. Our results also indicate that across all groups the main elements of the SOS response are always found in the large chromosome, whereas specialized additions are found in the smaller chromosomes and plasmids. Conclusions Our findings confirm that the SOS response of the Vibrionaceae is strongly linked with pathogenicity and dissemination of antibiotic resistance, and suggest that the characterization of the newly identified members of this regulon could provide key insights into the pathogenesis of Vibrio. The persistent location of key SOS genes in the large chromosome across several bacterial groups confirms that the SOS response plays an essential role in these organisms and sheds light into the mechanisms of evolution of global transcriptional networks involved in adaptability and rapid response to environmental changes, suggesting that small chromosomes may act as evolutionary test beds for the rewiring of transcriptional networks.
Summary Studying metal ion resistances gives us important insights into environmental processes and provides an understanding of basic living processes. This review concentrates on bacterial efflux systems for inorganic metal cations and anions, which have generally been found as resistance systems from bacteria isolated from metal-polluted environments. The protein products of the genes involved are sometimes prototypes of new families
Dietrich H. Nies; Simon Silver
Bacterial pathogens are examples of classical etiological agents of waterborne disease. While these agents no longer serve as major threats to U.S. water supplies, they are still important pathogens in areas with substandard sanitation and poor water treatment facilities. In th...
A newly discovered lignin peroxidase enzyme is provided. The enzyme is obtained from a bacterial source and is capable of degrading the lignin portion of lignocellulose in the presence of hydrogen peroxide. The enzyme is extracellular, oxidative, inducible by lignin, larch wood xylan, or related substrates and capable of attacking certain lignin substructure chemical bonds that are not degradable by fungal lignin peroxidases.
Crawford, Donald L. (Moscow, ID); Ramachandra, Muralidhara (Moscow, ID)
In this math activity, learners sort patterns into similar "families" or groups that have the same pattern, but different symbols. Then learners create their own patterns that fit into each family using stamps, stickers, and buttons. This activity guide contains a material list, sample questions to ask, literary connections, extensions, and alignment to local and national standards.
Houston, Children'S M.
This study utilized pyrosequencing-based phylogenetic library results to assess bacterial communities on the hands of women in Tanzania and compared these communities with bacteria assemblages on the hands of US women. Bacterial population profiles and phylogenetically based ordinate analysis demonstrated that the bacterial communities on hands were more similar for selected populations within a country than between the two countries considered. Organisms that have commonly been identified in prior human skin microbiome studies, including members of the Propionibacteriaceae, Staphylococcaceae and Streptococceacea families, were highly abundant on US hands and drove the clustering of US hand microbial communities into a distinct group. The most abundant bacterial taxa on Tanzanian hands were the soil-associated Rhodobacteraceae and Nocardioidaceae. These results help to expand human microbiome results beyond US and European populations, and the identification and abundance of soil-associated bacteria on Tanzanian hands demonstrated the important role of the environment in shaping the microbial communities on human hands. PMID:24817404
Hospodsky, Denina; Pickering, Amy J; Julian, Timothy R; Miller, Dana; Gorthala, Sisira; Boehm, Alexandria B; Peccia, Jordan
Considering the importance of its potential implications for human health, agricultural productivity, and ecosystem stability, surprisingly little is known regarding the composition or dynamics of the atmosphere's microbial inhabitants. Using a custom high-density DNA microarray, we detected and monitored bacterial populations in two U.S. cities over 17 weeks. These urban aerosols contained at least 1,800 diverse bacterial types, a richness approaching that of some soil bacterial communities. We also reveal the consistent presence of bacterial families with pathogenic members including environmental relatives of select agents of bioterrorism significance. Finally, using multivariate regression techniques, we demonstrate that temporal and meteorological influences can be stronger factors than location in shaping the biological composition of the air we breathe.
Brodie, Eoin L.; DeSantis, Todd Z.; Parker, Jordan P. Moberg; Zubietta, Ingrid X.; Piceno, Yvette M.; Andersen, Gary L.
Family violence occurs in many forms; the most prominent are domestic violence, child abuse, and elder abuse. Family violence affects many persons at some point in their life and constitutes the majority of violent acts in our society. Although there has been considerable study of the patterns, risk factors, and interventions for each form of family violence, great controversy still exists within each area. There is growing recognition of an overlap in the patterns, causes, and effective interventions across types of family violence. There is also an increasing awareness of the value of greater integration of theory and research across areas into a family violence approach through an ecological perspective. This review focuses on current knowledge related to these problems and suggests integrative steps to advance knowledge. PMID:16318607
Tolan, Patrick; Gorman-Smith, Deborah; Henry, David
Diverse bacterial lineages form beneficial infections with eukaryotic hosts. The origins, evolution, and breakdown of these mutualisms represent important evolutionary transitions. To examine these key events, we synthesize data from diverse interactions between bacteria and eukaryote hosts. Five evolutionary transitions are investigated, including the origins of bacterial associations with eukaryotes, the origins and subsequent stable maintenance of bacterial mutualism with hosts, the capture of beneficial symbionts via the evolution of strict vertical transmission within host lineages, and the evolutionary breakdown of bacterial mutualism. Each of these transitions has occurred many times in the history of bacterial–eukaryote symbiosis. We investigate these evolutionary events across the bacterial domain and also among a focal set of well studied bacterial mutualist lineages. Subsequently, we generate a framework for examining evolutionary transitions in bacterial symbiosis and test hypotheses about the selective, ecological, and genomic forces that shape these events.
Sachs, Joel L.; Skophammer, Ryan G.; Regus, John U.
Bacterial infections are common in tropical parts of the world and can include those species also seen regularly in temperate climates. Many tropical bacterial infections, however, are rarely diagnosed in temperate parts of the world and include bartonellosis, tropical ulcer, tropical pyomyositis, granuloma inguinale, lymphogranuloma venereum, yaws, pinta, melioidosis, and glanders. Some tropical bacterial diseases, eg, plague and anthrax, are
Omar Lupi; Vandana Madkan; Stephen K. Tyring
Summary Regulated promoters are useful tools for many aspects related to recombinant gene expression in bacteria, including for high?level expression of heterologous proteins and for expression at physiological levels in metabolic engineering applications. In general, it is common to express the genes of interest from an inducible promoter controlled either by a positive regulator or by a repressor protein. In this review, we discuss established and potentially useful positively regulated bacterial promoter systems, with a particular emphasis on those that are controlled by the AraC?XylS family of transcriptional activators. The systems function in a wide range of microorganisms, including enterobacteria, soil bacteria, lactic bacteria and streptomycetes. The available systems that have been applied to express heterologous genes are regulated either by sugars (l?arabinose, l?rhamnose, xylose and sucrose), substituted benzenes, cyclohexanone?related compounds, ??caprolactam, propionate, thiostrepton, alkanes or peptides. It is of applied interest that some of the inducers require the presence of transport systems, some are more prone than others to become metabolized by the host and some have been applied mainly in one or a limited number of species. Based on bioinformatics analyses, the AraC?XylS family of regulators contains a large number of different members (currently over 300), but only a small fraction of these, the XylS/Pm, AraC/PBAD, RhaR?RhaS/rhaBAD, NitR/PnitA and ChnR/Pb regulator/promoter systems, have so far been explored for biotechnological applications.
Brautaset, Trygve; Lale, Rahmi; Valla, Svein
Regulated promoters are useful tools for many aspects related to recombinant gene expression in bacteria, including for high-level expression of heterologous proteins and for expression at physiological levels in metabolic engineering applications. In general, it is common to express the genes of interest from an inducible promoter controlled either by a positive regulator or by a repressor protein. In this review, we discuss established and potentially useful positively regulated bacterial promoter systems, with a particular emphasis on those that are controlled by the AraC-XylS family of transcriptional activators. The systems function in a wide range of microorganisms, including enterobacteria, soil bacteria, lactic bacteria and streptomycetes. The available systems that have been applied to express heterologous genes are regulated either by sugars (L-arabinose, L-rhamnose, xylose and sucrose), substituted benzenes, cyclohexanone-related compounds, ?-caprolactam, propionate, thiostrepton, alkanes or peptides. It is of applied interest that some of the inducers require the presence of transport systems, some are more prone than others to become metabolized by the host and some have been applied mainly in one or a limited number of species. Based on bioinformatics analyses, the AraC-XylS family of regulators contains a large number of different members (currently over 300), but only a small fraction of these, the XylS/Pm, AraC/P(BAD), RhaR-RhaS/rhaBAD, NitR/PnitA and ChnR/Pb regulator/promoter systems, have so far been explored for biotechnological applications. PMID:21261879
Brautaset, Trygve; Lale, Rahmi; Valla, Svein
This document is made up of a selection of some of the papers distributed to participants in courses on "Family Health and Family Planning" which have been organized each year since 1973 by the International Children's Center and the World Health Organization Regional Office for Europe. Six courses, held between 1973 and 1978, brought together a…
World Health Organization, Copenhagen (Denmark). Regional Office for Europe.
Beta-lactamases are a superfamily of enzymes which degrade the ?-lactam class of antibiotics. They are produced endogenously by the bacterial cells, which when exposed to the ?-lactam class of antibiotics inactivate them by cleaving the ?-lactam ring. Based on the presence or absence of metallic ligand, ?-lactamases have been divided into two broad functional classes. ?-Lactamases are a constitutively evolving and expanding superfamily of enzymes, which could be further subdivided on the basis of presence/absence of conserved motifs. In the present study we have used the MEME/MAST suit to identify the patterns/motifs which are specific to a particular family or subfamily of ?-lactamases. The family specific patterns/motifs can be also useful in recognizing and assigning newly discovered ?-lactamases to one or the other family or subfamily. Cross-validation showed that the proposed method is highly sensitive and specific. We have also designed a webserver, LactFP, for this purpose.
Srivastava, Abhishikha; Goel, Manisha; Virdi, Jugsharan Singh; Kumar, Manish
... Self Advocacy Transitions Treatment Options Biomedical Treatments Nonmedical Interventions Related Approaches Evaluating Options Family Issues Stress Siblings Community Inclusion Autism and Faith Future Planning Government Benefits and Special Needs Trusts Letter of ...
Infections caused by bacteria are a leading cause of death worldwide. Although antibiotics remain a key clinical therapy, their effectiveness has been severely compromised by the development of drug resistance in bacterial pathogens. Multidrug efflux transporters-a common and powerful resistance mechanism-are capable of extruding a number of structurally unrelated antimicrobials from the bacterial cell, including antibiotics and toxic heavy metal ions, facilitating their survival in noxious environments. Transporters of the resistance-nodulation-cell division (RND) superfamily typically assemble as tripartite efflux complexes spanning the inner and outer membranes of the cell envelope. In Escherichia coli, the CusCFBA complex, which mediates resistance to copper(I) and silver(I) ions, is the only known RND transporter specific to heavy metals. Here, we describe the current knowledge of individual pump components of the Cus system, a paradigm for efflux machinery, and speculate on how RND pumps assemble to fight diverse antimicrobials. PMID:24702006
Delmar, Jared A; Su, Chih-Chia; Yu, Edward W
Bacterial genomes are remarkably stable from one generation to the next but are plastic on an evolutionary time scale, substantially shaped by horizontal gene transfer, genome rearrangement, and the activities of mobile DNA elements. This implies the existence of a delicate balance between the maintenance of genome stability and the tolerance of genome instability. In this review, we describe the specialized genetic elements and the endogenous processes that contribute to genome instability. We then discuss the consequences of genome instability at the physiological level, where cells have harnessed instability to mediate phase and antigenic variation, and at the evolutionary level, where horizontal gene transfer has played an important role. Indeed, this ability to share DNA sequences has played a major part in the evolution of life on Earth. The evolutionary plasticity of bacterial genomes, coupled with the vast numbers of bacteria on the planet, substantially limits our ability to control disease. PMID:24600039
Darmon, Elise; Leach, David R F
Heritable hypermutation in bacteria is mainly due to alterations in the methyl-directed mismatch repair (MMR) system. MMR-deficient strains have been described from several bacterial species, and all of the strains exhibit increased mutation frequency and recombination, which are important mechanisms for acquired drug resistance in bacteria. Antibiotics select for drug-resistant strains and refine resistance determinants on plasmids, thus stimulating DNA recombination via the MMR system. Antibiotics can also act as indirect promoters of antibiotic resistance by inducing the SOS system and certain error-prone DNA polymerases. These alterations have clinical consequences in that efficacious treatment of bacterial infections requires high doses of antibiotics and/or a combination of different classes of antimicrobial agents. There are currently few new drugs with low endogenous resistance potential, and the development of such drugs merits further research. PMID:21349992
Jolivet-Gougeon, Anne; Kovacs, Bela; Le Gall-David, Sandrine; Le Bars, Hervé; Bousarghin, Latifa; Bonnaure-Mallet, Martine; Lobel, Bernard; Guillé, François; Soussy, Claude-James; Tenke, Peter
Existence of nanobacteria received increasing attention both in environmental microbiology/geomicro-biology and in medical microbiology. In order to study a production of nanoforms by typical bacterial cells. Effects of different physical factors were investigated. Treatment of bacterial cultures with microwave radiation, or culturing in field of electric current resulted in formation a few types of nanocells. The number and type of nanoforms were determined with type and dose of the treatment. The produced nanoforms were: i) globules, ii) clusters of the globules--probably produced by liaison, iii) nanocells coated with membrane. The viability of the globules is an object opened for doubts. The nanocells discovered multiplication and growth on solidified nutrient media. The authors suggest that formation of nanocells is a common response of bacteria to stress-actions produced by different agents.
Vainshtein, Mikhail; Kudryashova, Ekaterina; Suzina, Natalia; Ariskina, Elena; Voronkov, Vadim
Self-propelling bacteria are a nanotechnology dream. These unicellular organisms are not just capable of living and reproducing, but they can swim very efficiently, sense the environment, and look for food, all packaged in a body measuring a few microns. Before such perfect machines can be artificially assembled, researchers are beginning to explore new ways to harness bacteria as propelling units for microdevices. Proposed strategies require the careful task of aligning and binding bacterial cells on synthetic surfaces in order to have them work cooperatively. Here we show that asymmetric environments can produce a spontaneous and unidirectional rotation of nanofabricated objects immersed in an active bacterial bath. The propulsion mechanism is provided by the self-assembly of motile Escherichia coli cells along the rotor boundaries. Our results highlight the technological implications of active matter’s ability to overcome the restrictions imposed by the second law of thermodynamics on equilibrium passive fluids.
Di Leonardo, R.; Angelani, L.; Dell'Arciprete, D.; Ruocco, G.; Iebba, V.; Schippa, S.; Conte, M. P.; Mecarini, F.; De Angelis, F.; Di Fabrizio, E.
In most bacteria two vital processes of the cell cycle: DNA replication and chromosome segregation overlap temporally. The action of replication machinery in a fixed location in the cell leads to the duplication of oriC regions, their rapid separation to the opposite halves of the cell and the duplicated chromosomes gradually moving to the same locations prior to cell division. Numerous proteins are implicated in co-replicational DNA segregation and they will be characterized in this review. The proteins SeqA, SMC/MukB, MinCDE, MreB/Mbl, RacA, FtsK/SpoIIIE playing different roles in bacterial cells are also involved in chromosome segregation. The chromosomally encoded ParAB homologs of active partitioning proteins of low-copy number plasmids are also players, not always indispensable, in the segregation of bacterial chromosomes. PMID:15827603
Bartosik, Aneta A; Jagura-Burdzy, Grazyna
It is shown that bacterial activity, even of slowly growing species, can be detected by precise interferometric measurements of refractive index changes of the culture medium. The bacteria-containing sample is kept in an isothermal block together with a reference liquid without bacteria. The biological activity is obtained from the difference of the index changes of these samples. Experiments were performed with Bacilo Calmette-Guérin. The order of magnitude of the observed total refractive index change was compatible with theoretical estimates based on the amount of available oxygen. An unexpected positive index change during the lag phase was observed, which might permit fast diagnostics in medical applications. This technique may provide cheap and quick tests of bacterial susceptibility with respect to antibiotics. PMID:12679859
Jardim, D Faragó; Santiago Neto, R Batista; Machado, R R P; Aarestrup, F M; de Mendonça, J P R F; Lesche, B
Summary: Bacterial cells utilize three-dimensional (3D) protein assemblies to perform important cellular functions such as growth, division, chemoreception, and motility. These assemblies are composed of mechanoproteins that can mechanically deform and exert force. Sometimes, small-nucleotide hydrolysis is coupled to mechanical deformations. In this review, we describe the general principle for an understanding of the coupling of mechanics with chemistry in mechanochemical systems. We apply this principle to understand bacterial cell shape and morphogenesis and how mechanical forces can influence peptidoglycan cell wall growth. We review a model that can potentially reconcile the growth dynamics of the cell wall with the role of cytoskeletal proteins such as MreB and crescentin. We also review the application of mechanochemical principles to understand the assembly and constriction of the FtsZ ring. A number of potential mechanisms are proposed, and important questions are discussed.
Sun, Sean X.; Jiang, Hongyuan
In this lesson, the relationship of addition to subtraction is explored with books and with connecting cubes. Students search for related addition and subtraction facts for a given number using a virtual or actual calculator to find differences. They also investigate fact families when one addend is 0 as well as when the addends are the same. Students will: find missing addends, review the additive identity, generate fact families given two addends or given one addend and the sum.
Data on the bacterial transformation of terpenoids published in the literature in the past decade are analyzed. Possible pathways for chemo-, regio- and stereoselective modifications of terpenoids are discussed. Considerable attention is given to new technological approaches to the synthesis of terpenoid derivatives suitable for the use in the perfume and food industry and promising as drugs and chiral intermediates for fine organic synthesis. The bibliography includes 246 references.
Grishko, V. V.; Nogovitsina, Y. M.; Ivshina, I. B.
Antibiotics play a major role in acne therapy. Physicians base treatment choices on personal perceptions of efficacy, cost-effectiveness or risk-benefit ratios and rarely take bacterial resistance into account. It is well documented that resistant strains of coagulase-negative staphylococci within the resident skin flora increase in both prevalence and population density as duration of therapy increases. Acne patients represent a considerable
E. A. Eady
The cytoplasm of living cells provides a complex fluid environment in which intracellular bacteria live and move. By analyzing the easily visible curved actin ``comet-tail'' of polymerization-based-motility bacteria such as Listeria monocytogenes, we can learn about sub-micron structure and dynamics of the tail and of the bacterial surface enzyme that catalyzes tail formation. By characterizing the motility, we can transform such motile systems into probes of the cytoplasmic environment.
Rutenberg, Andrew; Grant, Martin
\\u000a This chapter outlines how important properties of the bacterial nucleoid have been discovered by direct visualization of the\\u000a nucleoid in situ by microscopy. Relatively new tools for these investigations include fluorescent protein fusions, in situ\\u000a hybridization, cryo-EM, and atomic force microscopy. The nucleoid is not only just a passive carrier of chromosomal DNA, but\\u000a also actively influences global organization of
Opinion statement Spontaneous bacterial peritonitis (SBP) is the prototypical ascitic fluid infection occurring in patients with advanced liver\\u000a disease and ascites. The key to successful treatment of SBP is a knowledge of appropriate antibiotic regimens and an understanding\\u000a of the setting in which infection develops, particularly those individuals at high risk for infection. A high index of suspicion\\u000a should lead to
Donald J. Hillebrand
Feeding of bovine milk to mice induced a high incidence of bacterial translocation from the intestines to the mesenteric lymph nodes, and the bacteria involved were mainly members of the family Enterobacteriaceae. Supplementation of the milk diet with bovine lactoferrin or a pepsin-generated hydrolysate of bovine lactoferrin resulted in significant suppression of bacterial translocation. Our findings suggest that this ability of lactoferrin to inhibit bacterial translocation may be due to its suppression of bacterial overgrowth in the guts of milk-fed mice.
Teraguchi, S; Shin, K; Ogata, T; Kingaku, M; Kaino, A; Miyauchi, H; Fukuwatari, Y; Shimamura, S
The bacterial flagellar motor is a reversible rotary nano-machine, about 45 nm in diameter, embedded in the bacterial cell envelope. It is powered by the flux of H+ or Na+ ions across the cytoplasmic membrane driven by an electrochemical gradient, the proton-motive force or the sodium-motive force. Each motor rotates a helical filament at several hundreds of revolutions per second (hertz). In many species, the motor switches direction stochastically, with the switching rates controlled by a network of sensory and signalling proteins. The bacterial flagellar motor was confirmed as a rotary motor in the early 1970s, the first direct observation of the function of a single molecular motor. However, because of the large size and complexity of the motor, much remains to be discovered, in particular, the structural details of the torque-generating mechanism. This review outlines what has been learned about the structure and function of the motor using a combination of genetics, single-molecule and biophysical techniques, with a focus on recent results and single-molecule techniques. PMID:18812014
Sowa, Yoshiyuki; Berry, Richard M
Recent years have witnessed a resurgence of interest in how the bacterial chromosome is organized and how newly replicated chromosomes are faithfully segregated into daughter cells on cell division. In the past, the problem with studying bacterial chromosomes was their lack of any obvious morphology, combined with the lack of ability to readily separate DNA replication and segregation functions into distinct stages like those observed in eukaryotic cells. This was due to the overlapping nature of these events in most bacterial systems used in the laboratory. The situation has now changed as new tools have become available that enable chromosomes and specific chromosomal sites to be labelled and monitored throughout the cell cycle, and this has led to rapid progress and the discovery of many unexpected results. Historically, chromosome segregation was thought to be achieved through passive processes where chromosomes were separated through some kind of membrane/cell wall attachment and were moved apart as the cell grew (Jacob et al., 1963). We now know that this is not the case and that there are specific mechanisms to actively partition chromosomes. This review will focus principally on the Gram-positive sporulating bacterium Bacillus subtilis, but will also cover work carried out on Escherichia coli, in which valuable information has been obtained, and will cover the events that occur on termination of chromosome replication, chromosome decatenation and chromosome separation. PMID:11238959
Lewis, P J
Members of a new molecular family of bacterial nonspecific acid phosphatases (NSAPs), indicated as class C, were found to share significant sequence similarities to bacterial class B NSAPs and to some plant acid phosphatases, representing the first example of a family of bacterial NSAPs that has a relatively close eukaryotic counterpart. Despite the lack of an overall similarity, conserved sequence motifs were also identified among the above enzyme families (class B and class C bacterial NSAPs, and related plant phosphatases) and several other families of phosphohydrolases, including bacterial phosphoglycolate phosphatases, histidinol-phosphatase domains of the bacterial bifunctional enzymes imidazole-glycerolphosphate dehydratases, and bacterial, eukaryotic, and archaeal phosphoserine phosphatases and threalose-6-phosphatases. These conserved motifs are clustered within two domains, separated by a variable spacer region, according to the pattern [FILMAVT]-D-[ILFRMVY]-D-[GSNDE]-[TV]-[ILVAM]-[AT S VILMC]-X-żYFWHKR)-X-żYFWHNQż-X( 102,191)-żKRHNQż-G-D-żFYWHILVMCż-żQNHż-żFWYGPż-D -żPSNQYWż. The dephosphorylating activity common to all these proteins supports the definition of this phosphatase motif and the inclusion of these enzymes into a superfamily of phosphohydrolases that we propose to indicate as "DDDD" after the presence of the four invariant aspartate residues. Database searches retrieved various hypothetical proteins of unknown function containing this or similar motifs, for which a phosphohydrolase activity could be hypothesized.
Thaller, M. C.; Schippa, S.; Rossolini, G. M.
This brief review of the human Na/H exchanger gene family introduces a new classification with three subgroups to the SLC9 gene family. Progress in the structure and function of this gene family is reviewed with structure based on homology to the bacterial Na/H exchanger NhaA. Human diseases which result from genetic abnormalities of the SLC9 family are discussed although the exact role of these transporters in causing any disease is not established, other than poorly functioning NHE3 in congenital Na diarrhea
Donowitz, Mark; Tse, C. Ming; Fuster, Daniel
Antimicrobial peptides comprise a key component of innate immunity for a wide range of multicellular organisms. It has been shown that natural antimicrobial peptides and their analogs can permeate bacterial membranes selectively. There are a number of proposed models for this action, but the detailed molecular mechanism of the induced membrane permeation remains unclear. We investigate interactions between model bacterial membranes and a prototypical family of phenylene ethynylene-based antimicrobials with controllable hydrophilic and hydrophobic volume fractions, controllable charge placement. Preliminary results from synchrotron small angle x-ray scattering (SAXS) results will be presented.
Yang, Lihua; Mishra, Abhijit; Som, Abhigyan; Tew, Gregory N.; Wong, Gerard C. L.
The host actin nucleation machinery is subverted by many bacterial pathogens to facilitate their entry, motility, replication, and survival. The majority of research conducted in the past primarily focused on exploitation of a host actin nucleator, the Arp2/3 complex, by bacterial pathogens. Recently, new studies have begun to explore the role of formins, another family of host actin nucleators, in bacterial pathogenesis. This review provides an overview of recent advances in the study of the exploitation of the Arp2/3 complex and formins by bacterial pathogens. Secreted bacterial effector proteins seem to manipulate the regulation of these actin nucleators or functionally mimic them to drive bacterial entry, motility and survival within host cells. An enhanced understanding of how formins are exploited will provide us with greater insight into how a fundamental eurkaryotic cellular process is utilized by bacteria and will also advance our knowledge of host-pathogen interactions. PMID:24849003
Truong, Dorothy; Copeland, John W; Brumell, John H
Early embryos of many organisms develop outside the mother and are immediately confronted with myriads of potential colonizers. How these naive developmental stages control and shape the bacterial colonization is largely unknown. Here we show that early embryonic stages of the basal metazoan Hydra are able to control bacterial colonization by using maternal antimicrobial peptides. Antimicrobial peptides of the periculin family selecting for a specific bacterial colonization during embryogenesis are produced in the oocyte and in early embryos. If overexpressed in hydra ectodermal epithelial cells, periculin1a drastically reduces the bacterial load, indicating potent antimicrobial activity. Unexpectedly, transgenic polyps also revealed that periculin, in addition to bactericidal activity, changes the structure of the bacterial community. These findings delineate a role for antimicrobial peptides both in selecting particular bacterial partners during development and as important components of a “be prepared” strategy providing transgenerational protection.
Fraune, Sebastian; Augustin, Rene; Anton-Erxleben, Friederike; Wittlieb, Jorg; Gelhaus, Christoph; Klimovich, Vladimir B.; Samoilovich, Marina P.; Bosch, Thomas C. G.
Small intestinal bacterial overgrowth (SIBO), defined as excessive bacteria in the small intestine, remains a poorly understood disease. Initially thought to occur in only a small number of patients, it is now apparent that this disorder is more prevalent than previously thought. Patients with SIBO vary in presentation, from being only mildly symptomatic to suffering from chronic diarrhea, weight loss, and malabsorption. A number of diagnostic tests are currently available, although the optimal treatment regimen remains elusive. Recently there has been renewed interest in SIBO and its putative association with irritable bowel syndrome. In this comprehensive review, we will discuss the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of SIBO.
Dukowicz, Andrew C.; Levine, Gary M.
Dividing cells have mechanisms to ensure that their genomes are faithfully segregated into daughter cells. In bacteria, the description of these mechanisms has been considerably improved in the recent years. This review focuses on the different aspects of bacterial chromosome segregation that can be understood thanks to the studies performed with model organisms: Escherichia coli, Bacillus subtilis, Caulobacter crescentus and Vibrio cholerae. We describe the global positionning of the nucleoid in the cell and the specific localization and dynamics of different chromosomal loci, kinetic and biophysic aspects of chromosome segregation are presented. Finally, a presentation of the key proteins involved in the chromosome segregation is made. PMID:22201788
Possoz, Christophe; Junier, Ivan; Espeli, Olivier
A therapeutic model to help families activate experiential and right hemispheric functioning through hypnosis is presented in detail, together with a clinical illustration. Different situations in which this model is effective are mentioned and one such set of circumstances is described. (Author)
Araoz, Daniel L.; Negley-Parker, Esther
Parent Services Project (PSP), the first comprehensive program of resources and mental health activities for parents offered at child care centers in the San Francisco Bay Area (California), has expanded to centers in six states, serving over 19,000 families. This report describes the program's history, aims, and achievements, along with specific…
Link, Geoffrey; Beggs, Marjorie; Seiderman, Ethel
This quarterly publication, issued by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), contains articles dealing with family violence and alcohol abuse, children of alcoholic parents, training programs for counselors, and confidentiality of client records. The three articles on alcohol abuse suggest that: (1) there is a clear…
Sorgen, Carol, Ed.
Since its initial description in 1964, research has transformed spontaneous bacterial peritonitis (SBP) from a feared disease (with reported mortality of 90%) to a treatable complication of decompensated cirrhosis, albeit with steady prevalence and a high recurrence rate. Bacterial translocation, the key mechanism in the pathogenesis of SBP, is only possible because of the concurrent failure of defensive mechanisms in cirrhosis. Variants of SBP should be treated. Leucocyte esterase reagent strips have managed to shorten the ‘tap-to-shot’ time, while future studies should look into their combined use with ascitic fluid pH. Third generation cephalosporins are the antibiotic of choice because they have a number of advantages. Renal dysfunction has been shown to be an independent predictor of mortality in patients with SBP. Albumin is felt to reduce the risk of renal impairment by improving effective intravascular volume, and by helping to bind pro-inflammatory molecules. Following a single episode of SBP, patients should have long-term antibiotic prophylaxis and be considered for liver transplantation.
Koulaouzidis, Anastasios; Bhat, Shivaram; Saeed, Athar A
Summary Ever since the introduction of the Salmonella typhimurium mammalian microsome mutagenicity assay (the ‘Ames test’) over three decades ago, there has been a constant development of additional genotoxicity assays based upon the use of genetically engineered microorganisms. Such assays rely either on reversion principles similar to those of the Ames test, or on promoter–reporter fusions that generate a quantifiable dose?dependent signal in the presence of potential DNA damaging compounds and the induction of repair mechanisms; the latter group is the subject of the present review. Some of these assays were only briefly described in the scientific literature, whereas others have been developed all the way to commercial products. Out of these, only one, the umu?test, has been fully validated and ISO? and OECD standardized. Here we review the main directions undertaken in the construction and testing of bacterial?based genotoxicity bioassays, including the attempts to incorporate at least a partial metabolic activation capacity into the molecular design. We list the genetic modifications introduced into the tester strains, compare the performance of the different assays, and briefly describe the first attempts to incorporate such bacterial reporters into actual genotoxicity testing devices.
Biran, Alva; Yagur-Kroll, Sharon; Pedahzur, Rami; Buchinger, Sebastian; Reifferscheid, Georg; Ben-Yoav, Hadar; Shacham-Diamand, Yosi; Belkin, Shimshon
N-Linked glycosylation is an essential post-translational protein modification in the eukaryotic cell. The initial transfer of an oligosaccharide from a lipid carrier onto asparagine residues within a consensus sequon is catalyzed by oligosaccharyltransferase (OST). The first X-ray structure of a complete bacterial OST enzyme, Campylobacter lari PglB, was recently determined. To understand the mechanism of PglB, we have quantified sequon binding and glycosylation turnover in vitro using purified enzyme and fluorescently labeled, synthetic peptide substrates. Using fluorescence anisotropy, we determined a dissociation constant of 1.0 ?m and a strict requirement for divalent metal ions for consensus (DQNAT) sequon binding. Using in-gel fluorescence detection, we quantified exceedingly low glycosylation rates that remained undetected using in vivo assays. We found that an alanine in the ?2 sequon position, converting the bacterial sequon to a eukaryotic one, resulted in strongly lowered sequon binding, with in vitro turnover reduced 50,000-fold. A threonine is preferred over serine in the +2 sequon position, reflected by a 4-fold higher affinity and a 1.2-fold higher glycosylation rate. The interaction of the +2 sequon position with PglB is modulated by isoleucine 572. Our study demonstrates an intricate interplay of peptide and metal binding as the first step of protein N-glycosylation.
Gerber, Sabina; Lizak, Christian; Michaud, Gaelle; Bucher, Monika; Darbre, Tamis; Aebi, Markus; Reymond, Jean-Louis; Locher, Kaspar P.
Despite increases in single-parent families among Mexican Americans (MA), few studies have examined the association of family structure and family adjustment. Utilizing a diverse sample of 738 Mexican American families (21.7% single parent), the current study examined differences across family structure on early adolescent outcomes, family functioning, and parent-child relationship variables. Results revealed that early adolescents in single parent families reported greater school misconduct, CD/ODD and MDD symptoms, and greater parent-child conflict than their counterparts in two parent families. Single parent mothers reported greater economic hardship, depression and family stress. Family stress and parent-child conflict emerged as significant mediators of the association between family structure and early adolescent outcomes, suggesting important processes linking MA single parent families and adolescent adjustment.
Zeiders, Katharine H.; Roosa, Mark W.; Tein, Jenn-Yun
Proteins containing membrane attack complex/perforin (MACPF) domains play important roles in vertebrate immunity, embryonic development, and neural-cell migration. In vertebrates, the ninth component of complement and perforin form oligomeric pores that lyse bacteria and kill virus-infected cells, respectively. However, the mechanism of MACPF function is unknown. We determined the crystal structure of a bacterial MACPF protein, Plu-MACPF from Photorhabdus luminescens, to 2.0 angstrom resolution. The MACPF domain reveals structural similarity with poreforming cholesterol-dependent cytolysins (CDCs) from Gram-positive bacteria. This suggests that lytic MACPF proteins may use a CDC-like mechanism to form pores and disrupt cell membranes. Sequence similarity between bacterial and vertebrate MACPF domains suggests that the fold of the CDCs, a family of proteins important for bacterial pathogenesis, is probably used by vertebrates for defense against infection.
Rosado, Carlos J.; Buckle, Ashley M.; Law, Ruby H.P.; Butcher, Rebecca E.; Kan, Wan-Ting; Bird, Catherina H.; Ung, Kheng; Browne, Kylie A.; Baran, Katherine; Bashtannyk-Puhalovich, Tanya A.; Faux, Noel G.; Wong, Wilson; Porter, Corrine J.; Pike, Robert N.; Ellisdon, Andrew M.; Pearce, Mary C.; Bottomley, Stephen P.; Emsley, Jonas; Smith, A. Ian; Rossjohn, Jamie; Hartland, Elizabeth L.; Voskoboinik, Ilia; Trapani, Joseph A.; Bird, Phillip I.; Dunstone, Michelle A.; Whisstock, James C. (PMCI-A); (Monash); (Nottingham)
A previous report identified and classified a small family of Gram-negative bacterial drug and heavy metal efflux permeases, now commonly referred to as the RND family (TC no. 2.6). We here show that this family is actually a ubiquitous superfamily with representation in all major kingdoms. We report phylogenetic analyses that define seven families within the RND superfamily as follows:
Tsai-Tien Tseng; Kevin S. Gratwick; Justin Kollman; Daniel Park; Dietrich H. Nies; André Goffeau; Milton H. Saier
Paragangliomas are rare tumours of the autonomic nervous system and occur in sporadic and hereditary forms. They are usually benign and have a low mortality. However, they cause significant morbidity related to their mass effect. Genetic predisposition can occur within the familial tumour syndromes multiple endocrine neoplasia type 2 (MEN 2), von Hippel-Lindau (VHL) and neurofibromatosis type 1 (NF-1), or be due to mutations in genes specific to the development of paraganglioma only. Compared to sporadic forms, familial paragangliomas tend to present at a younger age and at multiple sites. Tumours should be diagnosed and resected as early as possible, as it has been shown that morbidity is related to tumour size. This article gives an overview of the current literature on the origin of the different forms of paragangliomas, DNA diagnosis, as well as biochemical and radiological screening guidelines.
Bereavement care is a vital but under-funded part of palliative care services, and there is growing evidence that people who have lost a loved one are at increased risk of serious illness. The Hospice of St. Francis in Berkhamsted is providing innovative care for families of patients before and after death. 'Life-changing' initiatives include cookery classes and pony rides. PMID:22908761
While active, controlled cellular suicide (autolysis) in bacteria is commonly observed, it has been hard to argue that autolysis can be beneficial to an individual who commits it. We propose a theoretical model that predicts that bacterial autolysis is evolutionarily advantageous to an individual and would fixate in physically structured environments for stationary phase colonies. We perform spatially resolved agent-based simulations of the model, which predict that lower mixing in the environment results in fixation of a higher autolysis rate from a single mutated cell, regardless of the colony's genetic diversity. We argue that quorum sensing will fixate as well, even if initially rare, if it is coupled to controlling the autolysis rate. The model does not predict a strong additional competitive advantage for cells where autolysis is controlled by quorum sensing systems that distinguish self from nonself. These predictions are broadly supported by recent experimental results in B. subtilis and S. pneumoniae.
Tchernookov, Martin; Nemenman, Ilya
Microorganisms and specifically motile bacteria have been recently added to the list of micro-actuators typically considered for the implementation of microsystems and microrobots. Such trend has been motivated by the fact these microorganisms are self-powered actuators with overall sizes at the lower end of the micrometer range and which have proven to be extremely effective in low Reynolds number hydrodynamic regime of usually less than 10(-2). Furthermore, the various sensors or taxes in bacteria influencing their movements can also be exploited to perform tasks that were previously considered only for futuristic artificial microrobots. Bacterial implementations and related issues are not only reviewed, but this paper also proposes many techniques and approaches that can be considered as building blocks for the implementations of more sophisticated microsystems and microrobots. PMID:22960952
We assessed the bacterial contamination of the pagers of healthcare personnel and the efficacy of disinfection with 70% isopropyl alcohol. Microorganisms were isolated from all pagers; 21% yielded Staphylococcus aureus, of which 14% were methicillin resistant. Cleaning with alcohol reduced the total colony count by an average of 94%. Bacterial load varied by healthcare worker group and service assignment. PMID:12026153
Singh, Deepjot; Kaur, Hanspreet; Gardner, William G; Treen, Lisa B
Bacterial meningitis is relatively common, can progress rapidly, and can result in death or permanent debilitation. This infection justifiably elicits strong emotional reactions and, hopefully, immediate medical intervention. This review is a brief presentation of the pathogenesis of bacterial meningitis and a review of current knowledge, literature, and recommendations on the subject of laboratory diagnosis of bacterial meningitis. Those who work in clinical microbiology laboratories should be familiar with the tests used in detecting bacteria and bacterial antigens in cerebrospinal fluid (CSF) and should always have the utmost appreciation for the fact that results of such tests must always be reported immediately. Academic and practical aspects of the laboratory diagnosis of bacterial meningitis presented in this review include the following: anatomy of the meninges; pathogenesis; changes in the composition of CSF; etiological agents; processing CSF; microscopic examination of CSF; culturing CSF; methods of detecting bacterial antigens and bacterial components in CSF (counter-immunoelectrophoresis, coagglutination, latex agglutination, enzyme-linked immunosorbent assay, Limulus amebocyte lysate assay, and gas-liquid chromatography); use of the polymerase chain reaction; and practical considerations for testing CSF for bacterial antigens.
Gray, L D; Fedorko, D P
Bacterial lipopolysaccharides (LPS) are the major outer surface membrane components present in almost all Gram-negative bacteria and act as extremely strong stimulators of innate or natural immunity in diverse eukaryotic species ranging from insects to humans. LPS consist of a poly- or oligosaccharide region that is anchored in the outer bacterial membrane by a specific carbohydrate lipid moiety termed lipid
Christian Alexander; E. T. Rietschel
The N-formyl peptide receptors (FPRs) are a family of G-protein coupled receptors that re- spond to proinflammatory N-formylated bacterial pep- tides (e.g., formyl-Met-Leu-Phe, fMLF) and, thus, con- tribute to the host response to bacterial infection. Paradoxically, a growing body of evidence suggests that some members of this receptor family may also be targets for certain anti-inflammatory molecules, includ- ing annexin
C. D. John; V. Sahni; D. Mehet; J. F. Morris; H. C. Christian; M. Perretti; R. J. Flower; E. Solito; J. C. Buckingham
Familial hypercholesterolemia is one of the most common hereditary metabolic disorders, untreated with grave cardiovascular consequences. A general practitioner will see at least one affected individual each month, but will rarely be aware of the diagnosis, though it is easily suspected: an LDL-cholesterol ??190?mg/dl, a family history of premature cardiovascular disease, or clinical signs as arcus lipoides, tendinous xanthomata, or a thickened Achilles' tendon must draw the attention to familial hypercholesterolemia. Because of the burden of high cholesterol levels from childhood on therapy should be initiated early enough, which has become greatly ameliorated since the introduction of statins. In conjunction with additional risk factors, notably low HDL-cholesterol or elevated lipoprotein(a) the cardiovascular sequelae can be dramatic and may call for more intense therapies. However, often the routine of successful cholesterol lowering covers the diagnosis nowadays, so that a heritable metabolic disorder is not suspected, which, however, prevents an effective prevention in relatives, particularly the children of the patient. PMID:23132157
Windler, E; Beil, F-U; Altenburg, C; Rinninger, F
Over the past decade or so, dramatic developments in our ability to experimentally determine the content and function of genomes have taken place. In particular, next-generation sequencing technologies are now inspiring a new understanding of bacterial transcriptomes on a global scale. In bacterial cells, whole-transcriptome studies have not received attention, owing to the general view that bacterial genomes are simple. However, several recent RNA sequencing results are revealing unexpected levels of complexity in bacterial transcriptomes, indicating that the transcribed regions of genomes are much larger and complex than previously anticipated. In particular, these data show a wide array of small RNAs, antisense RNAs, and alternative transcripts. Here, we review how current transcriptomics are now revolutionizing our understanding of the complexity and regulation of bacterial transcriptomes.
Cho, Suhyung; Cho, Yoobok; Lee, Sooin; Kim, Jayoung; Yum, Hyeji; Kim, Sun Chang
Quorum sensing is widely recognized as an efficient mechanism to regulate expression of specific genes responsible for communal behavior in bacteria. Several bacterial phenotypes essential for the successful establishment of symbiotic, pathogenic, or commensal relationships with eukaryotic hosts, including motility, exopolysaccharide production, biofilm formation, and toxin production, are often regulated by quorum sensing. Interestingly, eukaryotes produce quorum-sensing-interfering (QSI) compounds that have a positive or negative influence on the bacterial signaling network. This eukaryotic interference could result in further fine-tuning of bacterial quorum sensing. Furthermore, recent work involving the synthesis of structural homologs to the various quorum-sensing signal molecules has resulted in the development of additional QSI compounds that could be used to control pathogenic bacteria. The creation of transgenic plants that express bacterial quorum-sensing genes is yet another strategy to interfere with bacterial behavior. Further investigation on the manipulation of quorum-sensing systems could provide us with powerful tools against harmful bacteria.
Gonzalez, Juan E.; Keshavan, Neela D.
Describes family literacy, examining how families are already read by teachers, researchers, policymakers, and the media and arguing that the rhetoric of family literacy has defined the family in somewhat pathological terms. The paper examines the continued pervasiveness of deficit discourses to describe families, noting why it prevails in the…
Whitehouse Marianne; Colvin, Carolyn
This literature review provides an overview of the impact of dual careers on family and family therapy. The dual career family currently represents the most common married unit. Because both work and family stress impact psychological well-being variables such as depression and self-esteem, family and work can not be understood as two separate and…
Hill, Nicole R.
Pseudopterogorgia elisabethae is a common inhabitant of Caribbean reefs and is a well-known source of diterpenes with diverse biological activities. Notably, this octocoral is the sole source of the pseudopterosin family of anti-inflammatory diterpenes and is harvested to supply commercial demand for these metabolites. We have characterized the composition of the bacterial community associated with P. elisabethae collected from Providencia Island, Colombia, using both culture-dependent and culture-independent approaches. Culture-independent analysis revealed that the bacterial communities were composed of eight phyla, of which Proteobacteria was the most abundant. At the class level, bacterial communities were dominated by Gammaproteobacteria (82-87 %). Additionally, operational taxonomic units related to Pseudomonas and Endozoicomonas species were the most abundant phylotypes consistently associated with P. elisabethae colonies. Culture-dependent analysis resulted in the identification of 40 distinct bacteria classified as Bacilli (15), Actinobacteria (12), Gammaproteobacteria (9), Alphaproteobacteria (3), and Betaproteobacteria (1). Only one of the 40 cultured bacteria was closely related to a dominant phylotype detected in the culture-independent study, suggesting that conventional culturing techniques failed to culture the majority of octocoral-associated bacterial diversity. To the best of our knowledge, this is the first characterization of the bacterial diversity associated with P. elisabethae. PMID:23913197
Correa, Hebelin; Haltli, Brad; Duque, Carmenza; Kerr, Russell
We report analyses of 202 fully sequenced genomes for homologues of known protein constituents of the bacterial phosphoenolpyruvate-dependent phosphotransferase system (PTS). These included 174 bacterial, 19 archaeal, and 9 eukaryotic genomes. Homologues of PTS proteins were not identified in archaea or eukaryotes, showing that the horizontal transfer of genes encoding PTS proteins has not occurred between the three domains of life. Of the 174 bacterial genomes (136 bacterial species) analyzed, 30 diverse species have no PTS homologues, and 29 species have cytoplasmic PTS phosphoryl transfer protein homologues but lack recognizable PTS permeases. These soluble homologues presumably function in regulation. The remaining 77 species possess all PTS proteins required for the transport and phosphorylation of at least one sugar via the PTS. Up to 3.2% of the genes in a bacterium encode PTS proteins. These homologues were analyzed for family association, range of protein types, domain organization, and organismal distribution. Different strains of a single bacterial species often possess strikingly different complements of PTS proteins. Types of PTS protein domain fusions were analyzed, showing that certain types of domain fusions are common, while others are rare or prohibited. Select PTS proteins were analyzed from different phylogenetic standpoints, showing that PTS protein phylogeny often differs from organismal phylogeny. The results document the frequent gain and loss of PTS protein-encoding genes and suggest that the lateral transfer of these genes within the bacterial domain has played an important role in bacterial evolution. Our studies provide insight into the development of complex multicomponent enzyme systems and lead to predictions regarding the types of protein-protein interactions that promote efficient PTS-mediated phosphoryl transfer.
Barabote, Ravi D.; Saier, Milton H.
The emergence of linear bacterial chromosomes has overthrown the dogma of universal circularity of the bacterial chromosomes, and posed mechanistic and evolutionary implications not previously anticipated.
Carton W. Chen
Dynamical and physical investigations of asteroid families are reviewed. Particular attention is given to recent work carried out mainly by means of a combination of numerical integration and filtering techniques and aimed at assessing the accuracy of proper elements with respect to the linear theory as well as evaluating some aspects of the second-order fourth-degree analytical theory of Yuasa (1973). It is noted that recent numerical results show that the issue of proper elements has to be reconsidered, particularly concerning the effect of the proximity to the mean motion resonances.
Froeschle, Cl.; Froeschle, Ch.; Gonczi, R.; Farinella, P.; Carpino, M.
Ancestral homologues of the major eukaryotic cytoskeletal families, tubulin and actin, play critical roles in cytokinesis of bacterial cells. FtsZ is the ancestral homologue of tubulin and assembles into the Z ring that determines the division plane. FtsA is an ancestral homologue of actin and is involved in coordinating cell wall synthesis during cytokinesis. FtsA assists in the formation of the Z ring and also has a critical role in recruiting downstream division proteins to the Z ring to generate the divisome that divides the cell. Spatial regulation of cytokinesis occurs at the stage of Z ring assembly and regulation of cell size occurs at this stage or during Z ring maturation.
Pichoff, Sebastien; Du, Shishen
To date 142 species have been described in the Vibrionaceae family of bacteria, classified into seven genera; Aliivibrio, Echinimonas, Enterovibrio, Grimontia, Photobacterium, Salinivibrio and Vibrio. As vibrios are widespread in marine environments and show versatile metabolisms and ecologies, these bacteria are recognized as one of the most diverse and important marine heterotrophic bacterial groups for elucidating the correlation between genome evolution and ecological adaptation. However, on the basis of 16S rRNA gene phylogeny, we could not find any robust monophyletic lineages in any of the known genera. We needed further attempts to reconstruct their evolutionary history based on multilocus sequence analysis (MLSA) and/or genome wide taxonomy of all the recognized species groups. In our previous report in 2007, we conducted the first broad multilocus sequence analysis (MLSA) to infer the evolutionary history of vibrios using nine housekeeping genes (the 16S rRNA gene, gapA, gyrB, ftsZ, mreB, pyrH, recA, rpoA, and topA), and we proposed 14 distinct clades in 58 species of Vibrionaceae. Due to the difficulty of designing universal primers that can amplify the genes for MLSA in every Vibrionaceae species, some clades had yet to be defined. In this study, we present a better picture of an updated molecular phylogeny for 86 described vibrio species and 10 genome sequenced Vibrionaceae strains, using 8 housekeeping gene sequences. This new study places special emphasis on (1) eight newly identified clades (Damselae, Mediterranei, Pectenicida, Phosphoreum, Profundum, Porteresiae, Rosenbergii, and Rumoiensis); (2) clades amended since the 2007 proposal with recently described new species; (3) orphan clades of genomospecies F6 and F10; (4) phylogenetic positions defined in 3 genome-sequenced strains (N418, EX25, and EJY3); and (5) description of V. tritonius sp. nov., which is a member of the "Porteresiae" clade. PMID:24409173
Sawabe, Tomoo; Ogura, Yoshitoshi; Matsumura, Yuta; Feng, Gao; Amin, Akm Rohul; Mino, Sayaka; Nakagawa, Satoshi; Sawabe, Toko; Kumar, Ramesh; Fukui, Yohei; Satomi, Masataka; Matsushima, Ryoji; Thompson, Fabiano L; Gomez-Gil, Bruno; Christen, Richard; Maruyama, Fumito; Kurokawa, Ken; Hayashi, Tetsuya
To date 142 species have been described in the Vibrionaceae family of bacteria, classified into seven genera; Aliivibrio, Echinimonas, Enterovibrio, Grimontia, Photobacterium, Salinivibrio and Vibrio. As vibrios are widespread in marine environments and show versatile metabolisms and ecologies, these bacteria are recognized as one of the most diverse and important marine heterotrophic bacterial groups for elucidating the correlation between genome evolution and ecological adaptation. However, on the basis of 16S rRNA gene phylogeny, we could not find any robust monophyletic lineages in any of the known genera. We needed further attempts to reconstruct their evolutionary history based on multilocus sequence analysis (MLSA) and/or genome wide taxonomy of all the recognized species groups. In our previous report in 2007, we conducted the first broad multilocus sequence analysis (MLSA) to infer the evolutionary history of vibrios using nine housekeeping genes (the 16S rRNA gene, gapA, gyrB, ftsZ, mreB, pyrH, recA, rpoA, and topA), and we proposed 14 distinct clades in 58 species of Vibrionaceae. Due to the difficulty of designing universal primers that can amplify the genes for MLSA in every Vibrionaceae species, some clades had yet to be defined. In this study, we present a better picture of an updated molecular phylogeny for 86 described vibrio species and 10 genome sequenced Vibrionaceae strains, using 8 housekeeping gene sequences. This new study places special emphasis on (1) eight newly identified clades (Damselae, Mediterranei, Pectenicida, Phosphoreum, Profundum, Porteresiae, Rosenbergii, and Rumoiensis); (2) clades amended since the 2007 proposal with recently described new species; (3) orphan clades of genomospecies F6 and F10; (4) phylogenetic positions defined in 3 genome-sequenced strains (N418, EX25, and EJY3); and (5) description of V. tritonius sp. nov., which is a member of the “Porteresiae” clade.
Sawabe, Tomoo; Ogura, Yoshitoshi; Matsumura, Yuta; Feng, Gao; Amin, AKM Rohul; Mino, Sayaka; Nakagawa, Satoshi; Sawabe, Toko; Kumar, Ramesh; Fukui, Yohei; Satomi, Masataka; Matsushima, Ryoji; Thompson, Fabiano L.; Gomez-Gil, Bruno; Christen, Richard; Maruyama, Fumito; Kurokawa, Ken; Hayashi, Tetsuya
The contents of fed-batch composting (FBC) reactors often aggregate after prolonged operation. This process leads to irreversible\\u000a breakdown of the decomposition reaction and possible alteration of the bacterial communities. We compared the structures of\\u000a bacterial communities in reactors under aggregate and optimal conditions. The results of 16S rRNA gene clone analysis showed\\u000a that populations of the family Bacillaceae (such as
Keiko Watanabe; Norio Nagao; Tatsuki Toda; Norio Kurosawa
Cirrhotic patients are immunocompromised with a high risk of infection. Proinflammatory cytokines and hemodynamic circulation derangement further facilitate the development of serious consequences of infections. Other than spontaneous bacterial peritonitis, bacteremia and bacterial infections of other organ systems are frequently observed. Gram-negative enteric bacteria are the most common causative organism. Other bacterial infections, such as enterococci, Vibrio spp., Aeromonas spp., Clostridium spp., Listeria monocytogenes, Plesiomonas shigelloides and Mycobacterium tuberculosis are more prevalent and more virulent. Generally, intravenous third generation cephalosporins are recommended as empirical antibiotic therapy. Increased incidences of gram-positive and drug-resistant organisms have been reported, particularly in hospital-acquired infections and in patients receiving quinolones prophylaxis. This review focuses upon epidemiology, microbiology, clinical features and treatment of infections in cirrhosis other than spontaneous bacterial peritonitis, including pathogen-specific and liver disease-specific issues. PMID:22662285
Bunchorntavakul, Chalermrat; Chavalitdhamrong, Disaya
Cirrhotic patients are immunocompromised with a high risk of infection. Proinflammatory cytokines and hemodynamic circulation derangement further facilitate the development of serious consequences of infections. Other than spontaneous bacterial peritonitis, bacteremia and bacterial infections of other organ systems are frequently observed. Gram-negative enteric bacteria are the most common causative organism. Other bacterial infections, such as enterococci, Vibrio spp., Aeromonas spp., Clostridium spp., Listeria monocytogenes, Plesiomonas shigelloides and Mycobacterium tuberculosis are more prevalent and more virulent. Generally, intravenous third generation cephalosporins are recommended as empirical antibiotic therapy. Increased incidences of gram-positive and drug-resistant organisms have been reported, particularly in hospital-acquired infections and in patients receiving quinolones prophylaxis. This review focuses upon epidemiology, microbiology, clinical features and treatment of infections in cirrhosis other than spontaneous bacterial peritonitis, including pathogen-specific and liver disease-specific issues.
Bunchorntavakul, Chalermrat; Chavalitdhamrong, Disaya
We demonstrate that collective turbulentlike motion in a bacterial bath can power and steer the directed transport of mesoscopic carriers through the suspension. In our experiments and simulations, a microwedgelike "bulldozer" draws energy from a bacterial bath of varied density. We obtain that an optimal transport speed is achieved in the turbulent state of the bacterial suspension. This apparent rectification of random motion of bacteria is caused by polar ordered bacteria inside the cusp region of the carrier, which is shielded from the outside turbulent fluctuations.
Kaiser, Andreas; Peshkov, Anton; Sokolov, Andrey; ten Hagen, Borge; Löwen, Hartmut; Aranson, Igor S.
We demonstrate that collective turbulentlike motion in a bacterial bath can power and steer the directed transport of mesoscopic carriers through the suspension. In our experiments and simulations, a microwedgelike "bulldozer" draws energy from a bacterial bath of varied density. We obtain that an optimal transport speed is achieved in the turbulent state of the bacterial suspension. This apparent rectification of random motion of bacteria is caused by polar ordered bacteria inside the cusp region of the carrier, which is shielded from the outside turbulent fluctuations. PMID:24785075
Kaiser, Andreas; Peshkov, Anton; Sokolov, Andrey; ten Hagen, Borge; Löwen, Hartmut; Aranson, Igor S
This review compares the results of different methods of investigating the morphology of nucleoids of bacteria grown under conditions favoring short generation times. We consider the evidence from fixed and stained specimens, from phase-contrast and fluorescence microscopy of growing bacteria, and from electron microscopy of whole as well as thinly sectioned ones. It is concluded that the nucleoid of growing cells is in a dynamic state: part of the chromatin is "pulled out" of the bulk of the nucleoid in order to be transcribed. This activity is performed by excrescences which extend far into the cytoplasm so as to reach the maximum of available ribosomes. Different means of fixation provide markedly different views of the texture of the DNA-containing plasm of the bulk of the nucleoid. Conventional chemical fixatives stabilize the cytoplasm of bacteria but not their protein-low chromatin. Uranyl acetate does cross-link the latter well but only if the cytoplasm has first been fixed conventionally. In the interval between the two fixations, the DNA arranges itself in liquid-crystalline form, supposedly because of loss of supercoiling. In stark contrast, cryofixation preserves bacterial chromatin in a finely granular form, believed to reflect its native strongly negatively supercoiled state. In dinoflagellates the DNA of their permanently visible chromosomes (also low in histone-like protein) is natively present as a liquid crystal. The arrangement of chromatin in Epulocystis fishelsoni, one of the largest known prokaryotes, is briefly described. Images
Robinow, C; Kellenberger, E
Sitafloxacin is a fluoroquinolone antibacterial with in vitro activity against a broad range of Gram-positive and -negative bacteria, including anaerobic bacteria, as well as against atypical pathogens. It is approved in Japan for use in a number of bacterial infections caused by sitafloxacin-susceptible strains of Staphylococcus spp., Streptococcus pneumoniae, other Streptococcus spp., Enterococcus spp., Moraxella catarrhalis, Escherichia coli, Citrobacter spp., Klebsiella spp., Enterobacter spp., Serratia spp., Proteus spp., Morganella morganii, Haemophilus influenzae, Pseudomonas aeruginosa, Legionella pneumophila, Peptostreptococcus spp., Prevotella spp., Porphyromonas spp., Fusobacterium spp., Chlamydia trachomatis, Chlamydophila pneumoniae and Mycoplasma pneumoniae. In terms of clinical efficacy, oral sitafloxacin was noninferior to oral levofloxacin in the treatment of community-acquired pneumonia or an infectious exacerbation of chronic respiratory tract disease, noninferior to oral tosufloxacin in the treatment of community-acquired pneumonia, and noninferior to oral levofloxacin in the treatment of complicated urinary tract infections, according to the results of randomized, double-blind, multicentre, noninferiority trials. Noncomparative studies demonstrated the efficacy of oral sitafloxacin in otorhinolaryngological infections, urethritis in men, C. trachomatis-associated cervicitis in women and odontogenic infections. Gastrointestinal disorders and laboratory abnormalities were the most commonly occurring adverse reactions in patients receiving oral sitafloxacin. Adverse reactions reported in sitafloxacin recipients in the active comparator trials were of mild to moderate severity. PMID:21504249
Keating, Gillian M
All communities are dominated by a few species that account for most of the biomass and carbon cycling. On the other hand, a large number of species are represented by only a few individuals. In the case of bacteria, these rare species were until recently invisible. Owing to their low numbers, conventional molecular techniques could not retrieve them. Isolation in pure culture was the only way to identify some of them, but current culturing techniques are unable to isolate most of the bacteria in nature. The recent development of fast and cheap high-throughput sequencing has begun to allow access to the rare species. In the case of bacteria, the exploration of this rare biosphere has several points of interest. First, it will eventually produce a reasonable estimate of the total number of bacterial taxa in the oceans; right now, we do not even know the right order of magnitude. Second, it will answer the question of whether "everything is everywhere." Third, it will require hypothesizing and testing the ecological mechanisms that allow subsistence of many species in low numbers. And fourth, it will open an avenue of research into the immense reserve of genes with potential applications hidden in the rare biosphere. PMID:22457983
Prokaryotes come in a wide variety of shapes, determined largely by natural selection, physical constraints, and patterns of cell growth and division. Because of their relative simplicity, bacterial cells are excellent models for how genes and proteins can directly determine morphology. Recent advances in cytological methods for bacteria have shown that distinct cytoskeletal filaments composed of actin and tubulin homologs are important for guiding growth patterns of the cell wall in bacteria, and that the glycan strands that constitute the wall are generally perpendicular to the direction of growth. This cytoskeleton-directed cell wall patterning is strikingly reminiscent of how plant cell wall growth is regulated by microtubules. In rod-shaped bacilli, helical cables of actin-like MreB protein stretch along the cell length and orchestrate elongation of the cell wall, whereas the tubulin-like FtsZ protein directs formation of the division septum and the resulting cell poles. The overlap and interplay between these two systems and the peptidoglycan-synthesizing enzymes they recruit are the major driving forces of cylindrical shapes. Round cocci, on the other hand, have lost their MreBcables and instead mustgrowmainly via their division septum, giving them their characteristic round or ovoid shapes. Other bacteria that lack MreB homologs or even cell walls usedistinct cytoskeletal systemsto maintain their distinct shapes. Here I review what is known about the mechanisms that determine the shape of prokaryotic cells.
A variety of pathogenic bacteria produce phospholipases C, and since the discovery in 1944 that a bacterial toxin (Clostridium perfringens alpha-toxin) possessed an enzymatic activity, there has been considerable interest in this class of proteins. Initial speculation that all phospholipases C would have lethal properties has not been substantiated. Most of the characterized enzymes fall into one of four groups of structurally related proteins: the zinc-metallophospholipases C, the sphingomyelinases, the phosphatidylinositol-hydrolyzing enzymes, and the pseudomonad phospholipases C. The zinc-metallophospholipases C have been most intensively studied, and lethal toxins within this group possess an additional domain. The toxic phospholipases C can interact with eukaryotic cell membranes and hydrolyze phosphatidylcholine and sphingomyelin, leading to cell lysis. However, measurement of the cytolytic potential or lethality of phospholipases C may not accurately indicate their roles in the pathogenesis of disease. Subcytolytic concentrations of phospholipase C can perturb host cells by activating the arachidonic acid cascade or protein kinase C. Nonlethal phospholipases C, such as the Listeria monocytogenes PLC-A, appear to enhance the release of the organism from the host cell phagosome. Since some phospholipases C play important roles in the pathogenesis of disease, they could form components of vaccines. A greater understanding of the modes of action and structure-function relationships of phospholipases C will facilitate the interpretation of studies in which these enzymes are used as membrane probes and will enhance the use of these proteins as models for eukaryotic phospholipases C.
Titball, R W
There has been increasing concern from the public about personal health due to the significant rise in the daily use of electrical devices such as cell phones, radios, computers, GPS, video games and television. All of these devices create electromagnetic (EM) fields, which are simply magnetic and electric fields surrounding the appliances that simultaneously affect the human bio-system. Although these can affect the human system, obstacles can easily shield or weaken the electrical fields; however, magnetic fields cannot be weakened and can pass through walls, human bodies and most other objects. The present study was conducted to examine the possible effects of bacteria when exposed to magnetic fields. The results indicate that a strong causal relationship is not clear, since different magnetic fields affect the bacteria differently, with some causing an increase in bacterial cells, and others causing a decrease in the same cells. This phenomenon has yet to be explained, but the current study attempts to offer a mathematical explanation for this occurrence. The researchers added cultures to the magnetic fields to examine any effects to ion transportation. Researchers discovered ions such as potassium and sodium are affected by the magnetic field. A formula is presented in the analysis section to explain this effect.
The taxonomic composition and distribution of microorganisms differing in the degree of association with the intestinal mucosa of the pike (Lucius lucius) has been studied. Microorgansism of the families Enterobacteriaceae, Aeromonadaceae, and Vibrionaceae dominate in the gut microflora. Numerically prevailing bacterial species are characterized by high proteolytic and amylolytic enzyme activities as well as by high persistence accounted for by antilysozyme and antihistone activities. The results of this study show that Hafnia alvei, Yersinia ruckeri, Vibrio vulnificus, V. furnissii, Aeromonas salmonicida, and Shewanella putrefaciens may be regarded as normal components of the pike gut microflora. PMID:19198074
Izveskova, G I; Nemtseva, N V; Plotnikov, A O
This article describes how families are functioning in the Netherlands, and how family therapy is used in mental healthcare. In the open Dutch society, new ideas are easily incorporated, as exemplified by the rapid introduction and growth of family therapy in the 1980s. In recent decades, however, family therapy has lost ground to other treatment models that are more individually orientated, and adhere to stricter protocols. This decline of family therapy has been exacerbated by recent budget cuts in mental healthcare. In regular healthcare institutes family therapy now has a marginal position at best, although family treatment models are used in specific areas such as forensic treatments. In addition, the higher trained family therapists have found their own niches to work with couples and families. We argue that a stronger position of family therapy would be beneficial for patients and for families, in order to counteract the strong individualization of Dutch society. PMID:22515464
Wagenaar, Karin; Baars, Jan
\\u000a Microbe bioremediation is the application of biological treatment to the cleanup of hazardous contaminants in soil and surface\\u000a or subsurface waters. Normally microbe bioremediation treats organic contaminants. Most microbe bioremediation processes take\\u000a advantage of indigenous microorganisms, although some rely on the introduction of bacterial or fungal strains. Bacterial digestion\\u000a is the process of bacteria-consuming organic matter. The bacteria feed on
Martina Mackova; Ondrej Uhlik; Petra Lovecka; Jitka Viktorova; Martina Novakova; Katerina Demnerova; Michel Sylvestre; Tomas Macek
Native cellulose from the bacterium Acetobacter xylinum as well as acid-treated bacterial cellulose prepared from partial hydrolysis of the native bacterial cellulose with 2.5 N HCl were subjected to enzymatic hydrolysis by Trichoderma viride cellobiohydrolase I (CBH I) and endoglucanase II (EG II). The activities of the two enzymes were continuously monitored with an oxidation-reduction potential electrode based on the
Masahiro Samejima; Junji Sugiyama; Kiyohiko Igarashi; Karl-Erik L. Eriksson
OBJECTIVETo determine the natural history and pathogenesis of hearing loss in children with acute bacterial meningitis.DESIGNMulticentre prospective study.SETTING21 hospitals in the south and west of England and South Wales.SUBJECTS124 children between the ages of 4 weeks and 16 years with newly diagnosed bacterial meningitis.METHODSChildren underwent repeated audiological assessment with the first tests being performed within six hours of diagnosis. By
M P Richardson; A Reid; M J Tarlow; P T Rudd
The persistence of the nuclear family as the primary social unit in the United States and most all other societies, especially complex ones, is a fact. Values shape the definition of family, especially the "good family," and the "great debate" of this period on family failure, family corruption and the family's near demise originates in…
Sussman, Marvin B.
The pull for family is strong, almost primeval, most likely it is evolutionary, and for those lacking the benefit of family or Family Privilege, the loss of family is painful and profoundly sad. Young people who struggle to cope without stable family connections are profoundly aware of their lack of "Family Privilege." In this article, the author…
This evaluation report of the Family to Family Program assesses parental attitudes towards their Family to Family experience and the functioning of their emotionally impaired children. It reviews issues of goal achievement; the impact on the targeted problem; service population demographics; and sustainability. Related topics include…
Ramey, Luellen; Meyer, David P.
Uses data from 20 case studies of Black adult female children of alcoholic parents to discuss Family Hero role often assumed by oldest or only female child in Black alcoholism families. Explains how female-dominated survival role of Family Hero in Black families is significantly more related to racial and cultural factors than numbers alone may…
Brisbane, Francis L.
Homologues of the transcriptional regulator FNR fromEscherichia coli have been identified in a variety of taxonomically diverse bacterial species. Despite being structurally very similar, members of the FNR family have disparate regulatory roles. Those fromShewanella putrefaciens, Pseudomonas aeruginosa, Pseudomonas stutzeri andRhodopseudomonas palustris are functionally similar to FNR in that they regulate anaerobic respiration or carbon metabolism. Four rhizobial proteins (fromRhizobium
Stephen Spiro; Jivko V. Stoyanov; Stephen P. Kidd; Jon L. Hobman
The DedA protein family is a highly conserved and ancient family of membrane proteins with representatives in most sequenced genomes, including those of bacteria, archaea, and eukarya. The functions of the DedA family proteins remain obscure. However, recent genetic approaches have revealed important roles for certain bacterial DedA family members in membrane homeostasis. Bacterial DedA family mutants display such intriguing phenotypes as cell division defects, temperature sensitivity, altered membrane lipid composition, elevated envelope-related stress responses, and loss of proton motive force. The DedA family is also essential in at least two species of bacteria: Borrelia burgdorferi and Escherichia coli. Here, we describe the phylogenetic distribution of the family and summarize recent progress toward understanding the functions of the DedA membrane protein family.
Sikdar, Rakesh; Kumar, Sujeet; Boughner, Lisa A.
Ample evidence exists showing that eukaryotic signal molecules synthesized and released by the host can activate the virulence of opportunistic pathogens. The sensitivity of prokaryotes to host signal molecules requires the presence of bacterial sensors. These prokaryotic sensors, or receptors, have a double function: stereospecific recognition in a complex environment and transduction of the message in order to initiate bacterial physiological modifications. As messengers are generally unable to freely cross the bacterial membrane, they require either the presence of sensors anchored in the membrane or transporters allowing direct recognition inside the bacterial cytoplasm. Since the discovery of quorum sensing, it was established that the production of virulence factors by bacteria is tightly growth-phase regulated. It is now obvious that expression of bacterial virulence is also controlled by detection of the eukaryotic messengers released in the micro-environment as endocrine or neuro-endocrine modulators. In the presence of host physiological stress many eukaryotic factors are released and detected by Gram-negative bacteria which in return rapidly adapt their physiology. For instance, Pseudomonas aeruginosa can bind elements of the host immune system such as interferon-? and dynorphin and then through quorum sensing circuitry enhance its virulence. Escherichia coli sensitivity to the neurohormones of the catecholamines family appears relayed by a recently identified bacterial adrenergic receptor. In the present review, we will describe the mechanisms by which various eukaryotic signal molecules produced by host may activate Gram-negative bacteria virulence. Particular attention will be paid to Pseudomonas, a genus whose representative species, P. aeruginosa, is a common opportunistic pathogen. The discussion will be particularly focused on the pivotal role played by these new types of pathogen sensors from the sensing to the transduction mechanism involved in virulence factors regulation. Finally, we will discuss the consequence of the impact of host signal molecules on commensally or opportunistic pathogens associated with different human tissue.
Lesouhaitier, Olivier; Veron, Wilfried; Chapalain, Annelise; Madi, Amar; Blier, Anne-Sophie; Dagorn, Audrey; Connil, Nathalie; Chevalier, Sylvie; Orange, Nicole; Feuilloley, Marc
Codependency is a common and treatable family-system illness that develops in reaction to the stress of addiction or another "shameful secret" in a family member. This stressful environment induces emotional changes in each family member and creates a variety of pathologic family roles. For the family physician, brief therapy for the codependent family can be visibly effective when combined with follow-up and referral to resources such as Al-Anon family groups. PMID:3565221
Mulry, J T
The bacterial biota of the human vagina can have a profound impact on the health of women and their neonates. Changes in the vaginal microbiota have been associated with several adverse health outcomes including premature birth, pelvic inflammatory disease, and acquisition of HIV infection. Cultivation-independent molecular methods have provided new insights regarding bacterial diversity in this important niche, particularly in women with the common condition bacterial vaginosis (BV). PCR methods have shown that women with BV have complex communities of vaginal bacteria that include many fastidious species, particularly from the phyla Bacteroidetes and Actinobacteria. Healthy women are mostly colonized with lactobacilli such as Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus iners, though a variety of other bacteria may be present. The microbiology of BV is heterogeneous. The presence of Gardnerella vaginalis and Atopobium vaginae coating the vaginal epithelium in some subjects with BV suggests that biofilms may contribute to this condition.
Srinivasan, Sujatha; Fredricks, David N.
The bacterial biota of the human vagina can have a profound impact on the health of women and their neonates. Changes in the vaginal microbiota have been associated with several adverse health outcomes including premature birth, pelvic inflammatory disease, and acquisition of HIV infection. Cultivation-independent molecular methods have provided new insights regarding bacterial diversity in this important niche, particularly in women with the common condition bacterial vaginosis (BV). PCR methods have shown that women with BV have complex communities of vaginal bacteria that include many fastidious species, particularly from the phyla Bacteroidetes and Actinobacteria. Healthy women are mostly colonized with lactobacilli such as Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus iners, though a variety of other bacteria may be present. The microbiology of BV is heterogeneous. The presence of Gardnerella vaginalis and Atopobium vaginae coating the vaginal epithelium in some subjects with BV suggests that biofilms may contribute to this condition. PMID:19282975
Srinivasan, Sujatha; Fredricks, David N
The inflammasome is a multi-protein complex that induces maturation of inflammatory cytokines interleukin (IL)-1? and IL-18 through activation of caspase-1. Several nucleotide binding oligomerization domain-like receptor family members, including NLRP3, recognize unique microbial and danger components and play a central role in inflammasome activation. The NLRP3 inflammasome is critical for maintenance of homeostasis against pathogenic infections. However, inflammasome activation acts as a double-edged sword for various bacterial infections. When the IL-1 family of cytokines is secreted excessively, they cause tissue damage and extensive inflammatory responses that are potentially hazardous for the host. Emerging evidence has shown that diverse bacterial pathogens or their components negatively regulate inflammasome activation to escape the immune response. In this review, we discuss the current knowledge of the roles and regulation of the NLRP3 inflammasome during bacterial infections. Activation and regulation of the NLRP3 inflammasome should be tightly controlled to prevent virulence and pathology during infections. Understanding the roles and regulatory mechanisms of the NLRP3 inflammasome is essential for developing potential treatment approaches against pathogenic infections.
Marine bacteria and microalgae engage in dynamic symbioses mediated by small molecules. A recent study of Phaeobacter gallaeciensis, a member of the large roseobacter clade of ?-proteobacteria, and Emiliania huxleyi, a prominent member of the microphytoplankton found in large algal blooms, revealed that an algal senescence signal produced by E. huxleyi elicits the production of novel algaecides, the roseobacticides, from the bacterial symbiont. In this report, the generality of these findings are examined by expanding the number of potential elicitors. This expansion led to the identification of nine new members of the roseobacticide family, rare bacterial troponoids, which provide insights into both their biological roles and their biosynthesis. The qualitative and quantitative changes in the levels of roseobacticides induced by the additional elicitors and the elicitors’ varied efficiencies support the concept of host-targeted roseobacticide production. Structures of the new family members arise from variable substituents at the C3 and C7 positions of the roseobacticide core as the diversifying elements and suggest that the roseobacticides result from modifications and combinations of aromatic amino acids. Together these studies support a model in which algal senescence converts a mutualistic bacterial symbiont into an opportunistic parasite of its hosts.
Myxococcus xanthus, a common soil bacterium, plays an active role in the formation of spheroidal vaterite. Bacterial production of CO 2 and NH 3 and the transformation of the NH 3 to NH4+ and OH -, thus increasing solution pH and carbonate alkalinity, set the physicochemical conditions (high supersaturation) leading to vaterite precipitation in the microenvironment around cells, and directly onto the surface of bacterial cells. In the latter case, fossilization of bacteria occurs. Vaterite crystals formed by aggregation of oriented nanocrystals with c-axis normal to the bacterial cell-wall, or to the core of the spherulite when bacteria were not encapsulated. While preferred orientation of vaterite c-axis appears to be determined by electrostatic affinity (ionotropic effect) between vaterite crystal (0001) planes and the negatively charged functional groups of organic molecules on the bacterium cell-wall or on extracellular polymeric substances (EPS), analysis of the changes in the culture medium chemistry as well as high resolution transmission electron microscopy (HRTEM) observations point to polymorph selection by physicochemical (kinetic) factors (high supersaturation) and stabilization by organics, both connected with bacterial activity. The latter is in agreement with inorganic precipitation of vaterite induced by NH 3 and CO 2 addition in the protein-rich sterile culture medium. Our results as well as recent studies on vaterite precipitation in the presence of different types of bacteria suggest that bacterially mediated vaterite precipitation is not strain-specific, and could be more common than previously thought.
Rodriguez-Navarro, Carlos; Jimenez-Lopez, Concepcion; Rodriguez-Navarro, Alejandro; Gonzalez-Muńoz, Maria Teresa; Rodriguez-Gallego, Manuel
Bacterial taxonomy has progressed from reliance on highly artificial culture-dependent techniques involving the study of phenotype (including morphological, biochemical and physiological data) to the modern applications of molecular biology, most recently 16S rRNA gene sequencing, which gives an insight into evolutionary pathways (= phylogenetics). The latter is applicable to culture-independent approaches, and has led directly to the recognition of new uncultured bacterial groups, i.e. "Candidatus", which have been associated as the cause of some fish diseases, including rainbow trout summer enteritic syndrome. One immediate benefit is that 16S rRNA gene sequencing has led to increased confidence in the accuracy of names allocated to bacterial pathogens. This is in marked contrast to the previous dominance of phenotyping, and identifications, which have been subsequently challenged in the light of 16S rRNA gene sequencing. To date, there has been some fluidity over the names of bacterial fish pathogens, with some, for example Vibrio anguillarum, being divided into two separate entities (V. anguillarum and V. ordalii). Others have been combined, for example V. carchariae, V. harveyi and V. trachuri as V. harveyi. Confusion may result with some organisms recognized by more than one name; V. anguillarum was reclassified as Beneckea and Listonella, with Vibrio and Listonella persisting in the scientific literature. Notwithstanding, modern methods have permitted real progress in the understanding of the taxonomic relationships of many bacterial fish pathogens.
Purpose. To review the newer treatments for bacterial keratitis. Data Sources. PubMed literature search up to April 2012. Study Selection. Key words used for literature search: “infectious keratitis”, “microbial keratitis”, “infective keratitis”, “new treatments for infectious keratitis”, “fourth generation fluoroquinolones”, “moxifloxacin”, “gatifloxacin”, “collagen cross-linking”, and “photodynamic therapy”. Data Extraction. Over 2400 articles were retrieved. Large scale studies or publications at more recent dates were selected. Data Synthesis. Broad spectrum antibiotics have been the main stay of treatment for bacterial keratitis but with the emergence of bacterial resistance; there is a need for newer antimicrobial agents and treatment methods. Fourth-generation fluoroquinolones and corneal collagen cross-linking are amongst the new treatments. In vitro studies and prospective clinical trials have shown that fourth-generation fluoroquinolones are better than the older generation fluoroquinolones and are as potent as combined fortified antibiotics against common pathogens that cause bacterial keratitis. Collagen cross-linking was shown to improve healing of infectious corneal ulcer in treatment-resistant cases or as an adjunct to antibiotics treatment. Conclusion. Fourth-generation fluoroquinolones are good alternatives to standard treatment of bacterial keratitis using combined fortified topical antibiotics. Collagen cross-linking may be considered in treatment-resistant infectious keratitis or as an adjunct to antibiotics therapy.
Wong, Raymond L. M.; Gangwani, R. A.; Yu, Lester W. H.; Lai, Jimmy S. M.
The growing demand to fulfill the needs of present-day medicine in terms of novel effective molecules has lead to reexamining some of the old and known bacterial secondary metabolites. Bacterial prodigiosins (prodiginines) have a long history of being re markable multipurpose compounds, best examined for their anticancer and antimalarial activities. Production of prodigiosin in the most common producer strain Serratia marcescens has been described in great detail. However, few reports have discussed the ecophysiological roles of these molecules in the producing strains, as well as their antibiotic and UV-protective properties. This review describes recent advances in the production process, biosynthesis, properties, and applications of bacterial prodigiosins. Special emphasis is put on undecylprodigiosin which has generally been a less studied member of the prodigiosin family. In addition, it has been suggested that proteins involved in undecylprodigiosin synthesis, RedG and RedH, could be a useful addition to the biocatalytic toolbox being able to mediate regio- and stereoselective oxidative cyclization. Judging by the number of recent references (216 for the 2007-2013 period), it has become clear that undecylprodigiosin and other bacterial prodigiosins still hold surprises in terms of valuable properties and applicative potential to medical and other industrial fields and that they still deserve continuing research curiosity. PMID:24562326
Stankovic, Nada; Senerovic, Lidija; Ilic-Tomic, Tatjana; Vasiljevic, Branka; Nikodinovic-Runic, Jasmina
Many, if not most, bacterial species swim. The synthesis and operation of the flagellum, the most complex organelle of a bacterium, takes a significant percentage of cellular energy, particularly in the nutrient limited environments in which many motile species are found. It is obvious that motility accords cells a survival advantage over non-motile mutants under normal, poorly mixed conditions and is an important determinant in the development of many associations between bacteria and other organisms, whether as pathogens or symbionts and in colonization of niches and the development of biofilms. This survival advantage is the result of sensory control of swimming behaviour. Although too small to sense a gradient along the length of the cell, and unable to swim great distances because of buffetting by Brownian motion and the curvature resulting from a rotating flagellum, bacteria can bias their random swimming direction towards a more favourable environment. The favourable environment will vary from species to species and there is now evidence that in many species this can change depending on the current physiological growth state of the cell. In general, bacteria sense changes in a range of nutrients and toxins, compounds altering electron transport, acceptors or donors into the electron transport chain, pH, temperature and even the magnetic field of the Earth. The sensory signals are balanced, and may be balanced with other sensory pathways such as quorum sensing, to identify the optimum current environment. The central sensory pathway in this process is common to most bacteria and most effectors. The environmental change is sensed by a sensory protein. In most species examined this is a transmembrane protein, sensing the external environment, but there is increasing evidence for additional cytoplasmic receptors in many species. All receptors, whether sensing sugars, amino acids or oxygen, share a cytoplasmic signalling domain that controls the activity of a histidine protein kinase, CheA, via a linker protein, CheW. A reduction in an attractant generally leads to the increased autophosphorylation of CheA. CheA passes its phosphate to a small, single domain response regulator, CheY. CheY-P can interact with the flagellar motor to cause it to change rotational direction or stop. Signal termination either via a protein, CheZ, which increases the dephosphorylation rate of CheY-P or via a second CheY which acts as a phosphate sink, allows the cell to swim off again, usually in a new direction. In addition to signal termination the receptor must be reset, and this occurs via methylation of the receptor to return it to a non-signalling conformation. The way in which bacteria use these systems to move to optimum environments and the interaction of the different sensory pathways to produce species-specific behavioural response will be the subject of this review. PMID:10500847
Armitage, J P
This article represents the information about family and family therapy in the context of culture, traditions and contemporary changes of social situations in Russia. The legislation of family rights are mentioned within items about marriage and family in the Constitution, Civil Code and Family Code of the Russian Federation which has changed during recent years. The definition of family and description of family structure are given through the prism of the current demographic situation, dynamics of statistics of marriage and divorce rates, mental disorders, disabilities and such phenomena as social abandonment. The actual curriculum, teaching of family therapy and its disadvantages, system of continuous education, supervision and initiatives of the Institute of Integrative Family Therapy in improvement of preparing of specialists who can provide qualified psychosocial assistance for the family according to the actual needs of society are noted. The directions of state and private practice of family counselling and therapy both for psychiatric patients and medical patients, for adults and children in a family systemic approach are highlighted with an indication of the spectrum of techniques and methods used by Russian professionals. The main obstacles and perspectives of development of family therapy in Russia are summarized. PMID:22515460
Bebtschuk, Marina; Smirnova, Daria; Khayretdinov, Oleg
This book offers clear and practical guidelines to help engage families in student success. It shows families how to conduct a successful Family Reading Night at their school. Family Night themes include Scary Stories, Books We Love, Reading Olympics, Dr. Seuss, and other themes. Family reading nights invite parents to come to school with their…
Hutchins, Darcy; Greenfeld, Marsha; Epstein, Joyce
Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms. PMID:19440284
Seo, Jong-Su; Keum, Young-Soo; Li, Qing X
Although it has been clear for more than 2 decades that bacterial vaginosis increases the risk for preterm birth in some women, it is not yet fully understood why this association exists or how best to modify the risk. Incomplete understanding of this polymicrobial condition and difficulties in classification contribute to the challenge. The relationship between altered vaginal microflora and preterm birth is likely mediated by host immune responses. Because treatment of bacterial vaginosis during pregnancy does not improve preterm birth rates, and may in fact increase them, screening and treatment of asymptomatic pregnant women is discouraged. Symptomatic women should be treated for symptom relief. This article reviews the pathophysiology of bacterial vaginosis and controversy surrounding management during pregnancy. Agents currently recommended for treatment of this condition are reviewed. PMID:22060217
The purpose of this study was to determine if a single dose of radiation to the rat abdomen leads to bacterial translocation into the mesenteric lymph nodes (MLN). A second issue addressed was whether translocation correlates with anatomic damage to the mucosa. The radiated group (1100 cGy) which received anesthesia also was compared with a control group and a third group which received anesthesia alone but no abdominal radiation. Abdominal radiation lead to 100% positive cultures of MLN between 12 hr and 4 days postradiation. Bacterial translocation was almost nonexistent in the control and anesthesia group. Signs of inflammation and ulceration of the intestinal mucosa were not seen until Day 3 postradiation. Mucosal damage was maximal by Day 4. Bacterial translocation onto the MLN after a single dose of abdominal radiation was not apparently dependent on anatomical, histologic damage of the mucosa.
Guzman-Stein, G.; Bonsack, M.; Liberty, J.; Delaney, J.P.
Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.
Seo, Jong-Su; Keum, Young-Soo; Li, Qing X.
SUMMARY. Immediate family members of veterans diagnosed with Gulf War Illnesses often complain of fatiguing illnesses, and upon analysis they report similar signs and symptoms as their veteran family members. Since a relatively common finding in Gulf War Illness patients is a bacterial infection due to Mycoplasma species, we examined military families (149 patients: 42 veterans, 40 spouses, 32 other
Garth L. Nicolson; Marwan Y. Nasralla; Nancy L. Nicolson; Joerg Haier
A rational four-step strategy to identify novel bacterial glycosyl hydrolases (GH), in combination with various fungal enzymes,\\u000a was applied in order to develop tailored enzyme cocktails to efficiently hydrolyze pretreated lignocellulosic biomass. The\\u000a fungal cellulases include cellobiohydrolase I (CBH I; GH family 7A), cellobiohydrolase II (CBH II; GH family 6A), endoglucanase\\u000a I (EG I; GH family 7B), and ?-glucosidase (?G;
Dahai Gao; Shishir P. S. Chundawat; Tongjun Liu; Spencer Hermanson; Krishne Gowda; Phillip Brumm; Bruce E. Dale; Venkatesh Balan
Examines research on the construct of resiliency and examines factors that promote resiliency in individuals and families. Implications for family counselors, societal systems, and future research are discussed. (Author/MKA)
Buckley, Matthew R.; Thorngren, Jill M.; Kleist, David M.
The Family Focus Research project provided a comprehensive evaluation of home-based crisis intervention strategies for families with children at risk of placement into substitute care. It examined the relative costs and benefits of three types of brief, i...
J. R. Taplin C. Rowland
All bacteria form persisters, cells that are multidrug tolerant and therefore able to survive antibiotic treatment. Due to the low frequencies of persisters in growing bacterial cultures and the complex underlying molecular mechanisms, the phenomenon has been challenging to study. However, recent technological advances in microfluidics and reporter genes have improved this scenario. Here, we summarize recent progress in the field, revealing the ubiquitous bacterial stress alarmone ppGpp as an emerging central regulator of multidrug tolerance and persistence, both in stochastically and environmentally induced persistence. In several different organisms, toxin-antitoxin modules function as effectors of ppGpp-induced persistence. PMID:24766804
Maisonneuve, Etienne; Gerdes, Kenn
Autophagy is a housekeeping process that maintains cellular homeostasis through recycling of nutrients and degradation of damaged or aged cytoplasmic constituents. Over the past several years, accumulating evidence has suggested that autophagy can function as an intracellular innate defense pathway in response to infection with a variety of bacteria and viruses. Autophagy plays a role as a specialized immunologic effector and regulates innate immunity to exert antimicrobial defense mechanisms. Numerous bacterial pathogens have developed the ability to invade host cells or to subvert host autophagy to establish a persistent infection. In this review, we have summarized the recent advances in our understanding of the interaction between antibacterial autophagy (xenophagy) and different bacterial pathogens.
Yuk, Jae-Min; Yoshimori, Tamotsu
Background Inconsistencies are often observed in the genome annotations of bacterial strains. Moreover, these inconsistencies are often not reflected by sequence discrepancies, but are caused by wrongly annotated gene starts as well as mis-identified gene presence. Thus, tools are needed for improving annotation consistency and accuracy among sets of bacterial strain genomes. Results We have developed eCAMBer, a tool for efficiently supporting comparative analysis of multiple bacterial strains within the same species. eCAMBer is a highly optimized revision of our earlier tool, CAMBer, scaling it up for significantly larger datasets comprising hundreds of bacterial strains. eCAMBer works in two phases. First, it transfers gene annotations among all considered bacterial strains. In this phase, it also identifies homologous gene families and annotation inconsistencies. Second, eCAMBer, tries to improve the quality of annotations by resolving the gene start inconsistencies and filtering out gene families arising from annotation errors propagated in the previous phase. Conculsions eCAMBer efficiently identifies and resolves annotation inconsistencies among closely related bacterial genomes. It outperforms other competing tools both in terms of running time and accuracy of produced annotations. Software, user manual, and case study results are available at the project website: http://bioputer.mimuw.edu.pl/ecamber.
The GCN5-related N-acetyltransferase (GNAT) superfamily of proteins, widespread in eukaryotes and prokaryotes, can utilize acyl coenzyme A (acyl CoA) to acylate respective acceptor substrates and release both CoA and the acylated products. GNATs have been shown to be involved in multiple physiological events, including bacterial drug resistance, regulation of transcription, stress reaction, and metabolic flux, etc. In the last few years, the importance of GNATs has only emerged in eukaryotes, but bacterial GNATs, particularly those of pathogens, have only recently been explored. In this review, we summarize the main members, structures, inhibitors, and activators of proteins in the GNAT family. We focus on the roles of GNATs in bacteria, particularly Mycobacterium tuberculosis GNATs. PMID:24579671
Xie, Longxiang; Zeng, Jie; Luo, Hongping; Pan, Weihua; Xie, Jianping
Social capital has been extensively discussed in the literature as building blocks that individuals and communities utilize to leverage system resources. Similarly, some families also create capital, which can enable members of the family, such as children, to successfully negotiate the outside world. Families in poverty confront serious…
Belcher, John R.; Peckuonis, Edward V.; Deforge, Bruce R.
... Families & Friendships Military Sexual Trauma Depression mild Traumatic Brain Injury Life Stress Health & Wellness Anger Stigma Suicide Prevention ... Post-Traumatic Stress Sleep Alcohol & Drugs mild Traumatic Brain Injury Resilience Families with Kids Depression Families & Friendships Tobacco ...
This article discusses how families can increase family togetherness and improve physical fitness. The author provides easy ways to implement family friendly activities for improving and maintaining physical health. These activities include: walking, backyard games, and fitness challenges.
Grosse, Susan J.
... Family Life Health Management - Medical Home Family Dynamics Adoption & Foster Care Communication & Disciplines Types of Families Media ... About Breastfeeding Teen Parents Pacifier Safety Questions About Adoption Healthy Children Radio: Protecting Children From Sexual Abuse ( ...
BACKGROUND—The annual incidence of non-Hodgkin's lymphomas (NHL) is increasing by 3%-4% in different parts of the developed world. Excesses of NHL have been observed in populations exposed to immunosuppressants and to HIV, but these causes do not explain the increasing trends. It is suggested that delayed infection could explain NHL trends, through an impairment of the Th1/Th2 lymphocyte patterns.?METHODS—In a population-based study on 1388 patients with NHL, 354 with Hodgkin's disease (HD) and 1718 healthy controls, the age of first occurrence of bacterial and viral diseases was investigated. Clinical records were perused in one centre to check the anamnestic data.?FINDINGS—The age of occurrence of bacterial and viral diseases was significantly higher among NHL patients than in the controls. The association between later age at first bacterial or viral disease was limited to small families (OR= 1.95; 95% confidence intervals 1.26, 3.00, for age 4-8 at first infection; OR=1.91; 1.19, 3.06, for age 9+, compared with less than 4). The association was more obvious for bacterial diseases (possibly for the lower degree of misclassification). High grade lymphomas showed the strongest association. The later age of occurrence of bacterial or viral diseases in NHL patients is consistent with a higher incidence of lymphomas observed in higher social groups. No clear association was found between HD and age at first bacterial or viral diseases.?INTERPRETATION—It is proposed that delayed infection could explain the increasing NHL trends, through an impairment of the Th1/Th2 lymphocyte patterns. The model of delayed infection has been proposed also to explain increasing prevalence rates of asthma.??
Vineis, P; Miligi, L; Crosignani, P; Fontana, A; Masala, G; Nanni, O; Ramazzotti, V; Rodella, S; Stagnaro, E; Tumino, R; Vigano, C; Vindigni, C; Costantini, A
Five reports of familial mesothelioma in which mesotheliomas occurred in two or more family members have been recorded in the medical literature. In this report, we describe two examples of familial mesothelioma. In one family, three brothers who worked in the asbestos insulation industry developed mesothelioma. In the second family, the father, who was occupationally exposed to asbestos, died from a tubulopapillary peritoneal mesothelioma 11 years before his son died from an identical histologic type of peritoneal mesothelioma. Our report, as with those previously recorded, suggests that genetic factors may be important in the genesis of some mesotheliomas.
Hammar, S.P.; Bockus, D.; Remington, F.; Freidman, S.; LaZerte, G.
This study examines how family organization is associated with the quality of family life for parents in first marriages,\\u000a remarriages with biological children, and several types of stepfamilies. Data are drawn from the 1987–1988 National Survey\\u000a of Families and Households; only married couples in which both spouses participated in the survey and who had children under\\u000a age 19 in the
Patricia Voydanoff; Mark A. Fine; Brena W. Donnelly
Insertion sequences (ISs) are small transposable elements widespread in bacterial genomes, where they play an essential role in chromosome evolution by stimulating recombination and genetic flow. Despite their ubiquity, it is unclear how ISs interact with the host. Here, we report a survey of the orientation patterns of ISs in bacterial chromosomes with the objective of gaining insight into the interplay between ISs and host chromosomal functions. We find that a significant fraction of IS families present a consistent and family-specific orientation bias with respect to chromosomal DNA replication, especially in Firmicutes. Additionally, we find that the transposases of up to nine different IS families with different transposition pathways interact with the ? sliding clamp, an essential replication factor, suggesting that this is a widespread mechanism of interaction with the host. Although we find evidence that the interaction with the ? sliding clamp is common to all bacterial phyla, it also could explain the observed strong orientation bias found in Firmicutes, because in this group ? is asymmetrically distributed during synthesis of the leading or lagging strands. Besides the interaction with the ? sliding clamp, other asymmetries also play a role in the biased orientation of some IS families. The utilization of the highly conserved replication sliding clamps suggests a mechanism for host regulation of IS proliferation and also a universal platform for IS dispersal and transmission within bacterial populations and among phylogenetically distant species.
Gomez, Manuel J.; Diaz-Maldonado, Hector; Gonzalez-Tortuero, Enrique; Lopez de Saro, Francisco J.
Many drug candidates from marine and terrestrial invertebrates are suspected metabolites of uncultured bacterial symbionts. The antitumor polyketides of the pederin family, isolated from beetles and sponges, are an example. Drug development from such sources is commonly hampered by low yields and the difficulty of sustaining invertebrate cultures. To obtain insight into the true producer and find alternative supplies of
To understand bacterial phylogeny, it is essential that the following two critical issues be resolved: (i) development of well-defined (molecular) criteria for identifying the main groups within Bacteria, and (ii) to understand how the different main groups are related to each other and how they branched off from a common ancestor. These issues are not resolved at present. We have
Radhey S. Gupta; Emma Griffiths
Mass transfer experiments were conducted to determine the transport and interaction parameters of selected molecules in hydrated bacterial cellulose (BC) membranes. The objective was to determine physiochemical characteristics and elucidate the mechanisms governing transport in relation to the membrane structure. Pore and sorption models developed previously for the analysis of transport in hydrogel membranes were relevant to the cellulose membrane
Adam M. Sokolnicki; Robert J. Fisher; Timothy P. Harrah; David L. Kaplan
Integrons are assembly platforms — DNA elements that acquire open reading frames embedded in exogenous gene cassettes and convert them to functional genes by ensuring their correct expression. They were first identified by virtue of their important role in the spread of antibiotic-resistance genes. More recently, our understanding of their importance in bacterial genome evolution has broadened with the discovery
Protein phosphorylation on tyrosine has emerged as a key device in the control of numerous cellular functions in bacteria. In this article, we review the structure and function of bacterial tyrosine kinases and phosphatases. Phosphorylation is catalyzed by autophosphorylating adenosine triphosphate-dependent enzymes (bacterial tyrosine (BY) kinases) that are characterized by the presence of Walker motifs. The reverse reaction is catalyzed by three classes of enzymes: the eukaryotic-like phosphatases (PTPs) and dual-specific phosphatases; the low molecular weight protein-tyrosine phosphatases (LMW-PTPs); and the polymerase–histidinol phosphatases (PHP). Many BY kinases and tyrosine phosphatases can utilize host cell proteins as substrates, thereby contributing to bacterial pathogenicity. Bacterial tyrosine phosphorylation/dephosphorylation is also involved in biofilm formation and community development. The Porphyromonas gingivalis tyrosine phosphatase Ltp1 is involved in a restraint pathway that regulates heterotypic community development with Streptococcus gordonii. Ltp1 is upregulated by contact with S. gordonii and Ltp1 activity controls adhesin expression and levels of the interspecies signal AI-2.
Whitmore, Sarah E; Lamont, Richard J
Infectious complications are major causes of morbidity and mortality after liver transplantation, despite recent advances in the transplant field. Bacteria, fungi, viruses and parasites can cause infection before and after transplantation. Among them, bacterial infections are predominant during the first two months post-transplantation and affect patient and graft survival. They might cause surgical site infections, including deep intra-abdominal infections, bacteremia, pneumonia, catheter-related infections and urinary tract infections. The risk factors for bacterial infections differ between the periods after transplant, and between centers. Recently, the emergence of multi-drug resistant bacteria is great concern in liver transplant (LT) patients. The instructive data about effects of infections with extended-spectrum beta lactamase producing bacteria, carbapenem-resistant gram-negative bacteria, and glycopeptide-resistant gram-positive bacteria were reported on a center-by-center basis. To prevent post-transplant bacterial infections, proper strategies need to be established based upon center-specific data and evidence from well-controlled studies. This article reviewed the recent epidemiological data, risk factors for each type of infections and important clinical issues in bacterial infection after LT.
Kim, Sang Il
One hundred and ninety children with atopic eczema were studied prospectively for two and a half years. The mean period of observation was 13 months. Seventy six children (40%) had between them 164 episodes of exacerbation of eczema due to bacterial infection, and in 52 (32%) infection recurred within three months of a previous infection. Twenty five episodes (15%) led
T J David; G C Cambridge
Although it is well known that plants and animals harbor microbial symbionts that can influence host traits, the factors regulating the structure of these microbial communities often remain largely undetermined. This is particularly true for insect-associated microbial communities, as few cross-taxon comparisons have been conducted to date. To address this knowledge gap and determine how host phylogeny and ecology affect insect-associated microbial communities, we collected 137 insect specimens representing 39 species, 28 families, and 8 orders, and characterized the bacterial communities associated with each specimen via 16S rRNA gene sequencing. Bacterial taxa within the phylum Proteobacteria were dominant in nearly all insects sampled. On average, the insect-associated bacterial communities were not very diverse, with individuals typically harboring fewer than 8 bacterial phylotypes. Bacterial communities also tended to be dominated by a single phylotype; on average, the most abundant phylotype represented 54.7% of community membership. Bacterial communities were significantly more similar among closely related insects than among less-related insects, a pattern driven by within-species community similarity but detected at every level of insect taxonomy tested. Diet was a poor predictor of bacterial community composition. Individual insect species harbored remarkably unique communities: the distribution of 69.0% of bacterial phylotypes was limited to unique insect species, whereas only 5.7% of phylotypes were detected in more than five insect species. Together these results suggest that host characteristics strongly regulate the colonization and assembly of bacterial communities across insect lineages, patterns that are driven either by co-evolution between insects and their symbionts or by closely related insects sharing conserved traits that directly select for similar bacterial communities.
Jones, Ryan Thomas; Sanchez, Leticia Gonzales; Fierer, Noah
Family therapy views humans not as separate entities, but as embedded in a network of relationships, highlighting the reciprocal influences of one's behaviours on one another. This article gives an overview of family demographics and the implementation of family therapy in Hong Kong. We start with a review of the family demographics in Hong Kong and brief notes on families in mainland China. Demographics show that the landscape has changed markedly in the past decade, with more cross-border marriages, an increased divorce rate, and an ageing overall population - all of which could mean that there is increasing demand for professional family therapy interventions. However, only a limited number of professionals are practising the systems-based approach in Hong Kong. Some possible reasons as to why family therapy is not well disseminated and practised are discussed. These reasons include a lack of mental health policy to support family therapy, a lack of systematic family therapy training, and a shortage of skilled professionals. Furthermore, challenges in applying the western model in Chinese culture are also outlined. We conclude that more future research is warranted to investigate how family therapy can be adapted for Chinese families. PMID:22515459
Tse, Samson; Ng, Roger M K; Tonsing, Kareen N; Ran, Maosheng
Bacterial endosymbionts are common among arthropods, and maternally inherited forms can affect the reproductive and behavioural traits of their arthropod hosts. The prevalence of bacterial endosymbionts and their role in scorpion evolution have rarely been investigated. In this study, 61 samples from 40 species of scorpion in the family Vaejovidae were screened for the presence of the bacterial endosymbionts Cardinium, Rickettsia, Spiroplasma and Wolbachia. No samples were infected by these bacteria. However, one primer pair specifically designed to amplify Rickettsia amplified nontarget genes of other taxa. Similar off-target amplification using another endosymbiont-specific primer was also found during preliminary screenings. Results caution against the overreliance on previously published screening primers to detect bacterial endosymbionts in host taxa and suggest that primer specificity may be higher in primers targeting nuclear rather than mitochondrial genes. PMID:24373187
Bryson, Robert W
Neuronal and glial glutamate transporters remove the excitatory neurotransmitter glutamate from the synaptic cleft and thus prevent neurotoxicity. The proteins belong to a large and widespread family of secondary transporters, including bacterial glutamate, serine, and C4-dicarboxylate transporters; mammalian neutral-amino-acid transporters; and an increasing number of bacterial, archaeal, and eukaryotic proteins that have not yet been functionally characterized. Sixty members of the glutamate transporter family were found in the databases on the basis of sequence homology. The amino acid sequences of the carriers have diverged enormously. Homology between the members of the family is most apparent in a stretch of approximately 150 residues in the C-terminal part of the proteins. This region contains four reasonably well-conserved sequence motifs, all of which have been suggested to be part of the translocation pore or substrate binding site. Phylogenetic analysis of the C-terminal stretch revealed the presence of five subfamilies with characterized members: (i) the eukaryotic glutamate transporters, (ii) the bacterial glutamate transporters, (iii) the eukaryotic neutral-amino-acid transporters, (iv) the bacterial C4-dicarboxylate transporters, and (v) the bacterial serine transporters. A number of other subfamilies that do not contain characterized members have been defined. In contrast to their amino acid sequences, the hydropathy profiles of the members of the family are extremely well conserved. Analysis of the hydropathy profiles has suggested that the glutamate transporters have a global structure that is unique among secondary transporters. Experimentally, the unique structure of the transporters was recently confirmed by membrane topology studies. Although there is still controversy about part of the topology, the most likely model predicts the presence of eight membrane-spanning ?-helices and a loop-pore structure which is unique among secondary transporters but may resemble loop-pores found in ion channels. A second distinctive structural feature is the presence of a highly amphipathic membrane-spanning helix that provides a hydrophilic path through the membrane. Recent data from analysis of site-directed mutants and studies on the mechanism and pharmacology of the transporters are discussed in relation to the structural model.
Slotboom, Dirk Jan; Konings, Wil N.; Lolkema, Juke S.
Sigma factors provide promoter recognition specificity to RNA polymerase holoenzyme, contribute to DNA strand separation, and then dissociate from the core enzyme following transcription initiation. As the regulon of a single sigma factor can be composed of hundreds of genes, sigma factors can provide effective mechanisms for simultaneously regulating expression of large numbers of prokaryotic genes. One newly emerging field is identification of the specific roles of alternative sigma factors in regulating expression of virulence genes and virulence-associated genes in bacterial pathogens. Virulence genes encode proteins whose functions are essential for the bacterium to effectively establish an infection in a host organism. In contrast, virulence-associated genes can contribute to bacterial survival in the environment and therefore may enhance the capacity of the bacterium to spread to new individuals or to survive passage through a host organism. As alternative sigma factors have been shown to regulate expression of both virulence and virulence-associated genes, these proteins can contribute both directly and indirectly to bacterial virulence. Sigma factors are classified into two structurally unrelated families, the ?70 and the ?54 families. The ?70 family includes primary sigma factors (e.g., Bacillus subtilis ?A) as well as related alternative sigma factors; ?54 forms a distinct subfamily of sigma factors referred to as ?N in almost all species for which these proteins have been characterized to date. We present several examples of alternative sigma factors that have been shown to contribute to virulence in at least one organism. For each sigma factor, when applicable, examples are drawn from multiple species.
Kazmierczak, Mark J.; Wiedmann, Martin; Boor, Kathryn J.
Trimethoprim-Sulfamethoxazole has been used successfully in the treatment of a nocardial brain abscess and was recently found to be also effective in the treatment of bacterial brain abscess. During the past year five patients with bacterial meningitis we...
Z. Farid N. I. Girgis W. Yassin D. C. Edman W. F. Miner
We are applying a comprehensive yet focused structural genomics approach to determine the atomic resolution crystal structures of key bacterial virulence factors from high priority bacterial pathogens. Knowledge of protein structure and inhibitor complexe...
R. C. Liddington
Studies have been underway at the laboratories of the Southeastern Cooperative Fish Disease Project of the Agricultural Experiment Station at Auburn University to investigate suspected bacterial infection of catfish eggs. The bacterial organisms of the ge...
J. H. Schachte
Animals are colonized by coevolved bacterial communities, which contribute to the host’s health. This commensal microbiota is often highly specific to its host-species, inferring strong selective pressures on the associated microbes. Several factors, including diet, mucus composition, and the immune system have been proposed as putative determinants of host-associated bacterial communities. Here we report that species-specific antimicrobial peptides account for different bacterial communities associated with closely related species of the cnidarian Hydra. Gene family extensions for potent antimicrobial peptides, the arminins, were detected in four Hydra species, with each species possessing a unique composition and expression profile of arminins. For functional analysis, we inoculated arminin-deficient and control polyps with bacterial consortia characteristic for different Hydra species and compared their selective preferences by 454 pyrosequencing of the bacterial microbiota. In contrast to control polyps, arminin-deficient polyps displayed decreased potential to select for bacterial communities resembling their native microbiota. This finding indicates that species-specific antimicrobial peptides shape species-specific bacterial associations.
Franzenburg, Soren; Walter, Jonas; Kunzel, Sven; Wang, Jun; Baines, John F.; Bosch, Thomas C. G.; Fraune, Sebastian
Bacterial pathogens cause significant morbidity and mortality annually to both humans and animals. With the rampant spread of drug resistance and the diminishing effectiveness of current antibiotics, there is a pressing need for effective diagnostics for detection of bacterial pathogens and their drug resistances. Bacteriophages offer several unique opportunities for bacterial detection. This review highlights the means by which bacteriophages have been utilized to achieve and facilitate specific bacterial detection. PMID:24658771
van der Merwe, R G; van Helden, P D; Warren, R M; Sampson, S L; Gey van Pittius, N C
Small intestinal bacterial overgrowth (SIBO) is a clinical condition characterized by a malabsorption syndrome due to an increase in microorganisms within the small intestine. The main mechanisms restricting bacterial colonization in the upper gut are the gastric acid barrier, mucosal and systemic immunity and intestinal clearance. When these mechanisms fail, bacterial overgrowth develops. Diarrhea, steatorrhea, chronic abdominal pain, bloating and
Antonio Gasbarrini; Maurizio Gabrielli; Emidio Scarpellini; Andrea Lupascu; Veronica Ojetti; Giovanni Gasbarrini
Bacterial translocation is defined as the passage of viable indigenous bacteria from the gastrointestinal tract to extraintestinal sites, such as the mesenteric-lymph-node complex, liver, spleen and bloodstream. Three major mechanisms promote bacterial translocation: intestinal bacterial overgrowth, deficiencies in host immune defenses and increased permeability or damage to the intestinal mucosal barrier.
Rodney D. Berg
Insects can readily spread certain bacterial pathogens as well as make the wound through which infection occurs, but with few exceptions bacterial diseases are not entirely dependent on insects for their dissemination or for the inoculation of the pathogen into the plant tissues. In fireblight of pome fruits caused by Erwinia amylovora pollinating insects are known to carry bacterial ooze
A. C. Hayward
Bacterial oesophagitis is an uncommon and poorly described entity affecting particularly the immunosuppressed patient. The diagnosis rests on the demonstration of bacterial invasion of the oesophageal wall in the absence of other pathological processes. The causative organisms usually are Gram-positive cocci and there may be associated bacteraemia. The case report describes a leukaemic patient with bacteraemic bacterial oesophagitis. Images Figure 1
Radhi, J. M.; Schweiger, F.
The normal indigenous intestinal microflora consists of about 1015 bacteria that under physiological conditions reside mainly in the lower gastrointestinal tract. Bacterial overgrowth implies abnormal bacterial colonization of the upper gut, resulting from failure of specific defense mechanisms restricting colonization under physiological conditions. At present two types of bacterial overgrowth with defined pathogenesis can be distinguished: (1) gastric overgrowth with
This bulletin focuses on family participation in mental health policymaking and highlights state efforts to increase family involvement. Articles include: (1) "Promoting Family Member Involvement in Children's Mental Health Policy Making Bodies," which describes how different states are promoting family member involvement in various statutory and…
Caplan, Elizabeth, Ed.; Blankenship, Kelly, Ed.; McManus, Marilyn, Ed.
This issue of "Focus on Law Studies""contains a special emphasis on teaching about law and the family", in the form of the following three articles: "Teaching Family Law: Growing Pains and All" (Susan Frelich Appleton); "The Family Goes to Court: Including Law in a Sociological Perspective on the Family" (Mary Ann Lamanna); and Michael Grossberg's…
Ryan, John Paul, Ed.
The family is centre stage of many current policy agendas and this is an exciting time to expand the understanding of the wider benefits of learning as a family and in a family. This article aims to open up new discussions and debate on using the concept of "family capital". The author states that as the debate on the social value of learning and…
Explores the definition of family. Considers three facets of the contemporary family measured by U.S. Census statistics: (1) marriage and divorce trends; (2) declining fertility; and (3) the rise in single-headed families. Addresses the societal changes (economic, cultural, legal, and technological) that have influenced the changes in family…
Seibert, M. Therese; Willetts, Marion C.
Many bacterial plasmids replicate by a rolling-circle (RC) mechanism. Their replication properties have many similarities to as well as significant differences from those of single-stranded DNA (ssDNA) coliphages, which also replicate by an RC mechanism. Studies on a large number of RC plasmids have revealed that they fall into several families based on homology in their initiator proteins and leading-strand origins. The leading-strand origins contain distinct sequences that are required for binding and nicking by the Rep proteins. Leading-strand origins also contain domains that are required for the initiation and termination of replication. RC plasmids generate ssDNA intermediates during replication, since their lagging-strand synthesis does not usually initiate until the leading strand has been almost fully synthesized. The leading- and lagging-strand origins are distinct, and the displaced leading-strand DNA is converted to the double-stranded form by using solely the host proteins. The Rep proteins encoded by RC plasmids contain specific domains that are involved in their origin binding and nicking activities. The replication and copy number of RC plasmids, in general, are regulated at the level of synthesis of their Rep proteins, which are usually rate limiting for replication. Some RC Rep proteins are known to be inactivated after supporting one round of replication. A number of in vitro replication systems have been developed for RC plasmids and have provided insight into the mechanism of plasmid RC replication.
Khan, S A
\\u000a Family is a unique relationship context that influences the contents and processes of identity. The identity of individuals\\u000a emerges, at least in part, from being members of a family. Moreover, the family context influences not only the development\\u000a of one’s personal identity as a family member but also other aspects of personal identity. Family is not a neutral environment\\u000a for
Eugenia Scabini; Claudia Manzi
We determine and relate the characteristic velocity, length, and time scales for bacterial motion in swarming colonies of Paenibacillus dendritiformis growing on semi-solid agar substrates. The bacteria swim within a thin fluid layer, and they form long-lived jets and vortices. These coherent structures lead to anisotropy in velocity spatial correlations and to a two-step relaxation in velocity temporal correlations. The mean squared displacement of passive tracers exhibits a short-time regime with nearly ballistic transport and a diffusive long-time regime. We find that various definitions of the correlation length all lead to length scales that are, surprisingly, essentially independent of the mean bacterial speed, while the correlation time is linearly proportional to the ratio of the correlation length to the mean speed.
Zhang, H. P.; Be'er, Avraham; Smith, Rachel S.; Florin, E.-L.; Swinney, Harry L.
The phenomenon of diauxic growth is a classical problem of bacterial gene regulation. The most well studied example of this phenomenon is the glucose-lactose diauxie, which occurs because the expression of the lac operon is strongly repressed in the presence of glucose. This repression is often explained by appealing to molecular mechanisms such as cAMP activation and inducer exclusion. I will begin by analyzing data showing that these molecular mechanisms cannot explain the strong lac repression because they exert a relatively weak effect. I will then present a minimal model accounting only for enzyme induction and dilution, which yields strong repression despite the absence of catabolite repression and inducer exclusion. The model also explains the growth patterns observed in batch and continuous cultures of various bacterial strains and substrate mixtures. The talk will conclude with a discussion of the experimental evidence regarding positive feedback, the key component of the minimal model.
For the first time, bacterial spores have been evaluated as vaccine vehicles. Bacillus subtilis spores displaying the tetanus toxin fragment C (TTFC) antigen were used for oral and intranasal immunization and were shown to generate mucosal and systemic responses in a murine model. TTFC-specific immunoglobulin G titers in serum (determined by enzyme-linked immunosorbent assay) reached significant levels 33 days after oral dosing, while responses against the spore coat proteins were relatively low. Tetanus antitoxin levels were sufficient to protect against an otherwise lethal challenge of tetanus toxin (20 50% lethal doses). The robustness and long-term storage properties of bacterial spores, coupled with simplified genetic manipulation and cost-effective manufacturing, make them particularly attractive vehicles for oral and intranasal vaccination.
Duc, Le H.; Hong, Huynh A.; Fairweather, Neil; Ricca, Ezio; Cutting, Simon M.
Cold-water coral reefs are known to locally enhance the diversity of deep-sea fauna as well as of microbes. Sponges are among the most diverse faunal groups in these ecosystems, and many of them host large abundances of microbes in their tissues. In this study, twelve sponge species from three cold-water coral reefs off Norway were investigated for the relationship between sponge phylogenetic classification (species and family level), as well as sponge type (high versus low microbial abundance), and the diversity of sponge-associated bacterial communities, taking also geographic location and water depth into account. Community analysis by Automated Ribosomal Intergenic Spacer Analysis (ARISA) showed that as many as 345 (79%) of the 437 different bacterial operational taxonomic units (OTUs) detected in the dataset were shared between sponges and sediments, while only 70 (16%) appeared purely sponge-associated. Furthermore, changes in bacterial community structure were significantly related to sponge species (63% of explained community variation), sponge family (52%) or sponge type (30%), whereas mesoscale geographic distances and water depth showed comparatively small effects (<5% each). In addition, a highly significant, positive relationship between bacterial community dissimilarity and sponge phylogenetic distance was observed within the ancient family of the Geodiidae. Overall, the high diversity of sponges in cold-water coral reefs, combined with the observed sponge-related variation in bacterial community structure, support the idea that sponges represent heterogeneous, yet structured microbial habitats that contribute significantly to enhancing bacterial diversity in deep-sea ecosystems. PMID:23393586
Schöttner, Sandra; Hoffmann, Friederike; Cárdenas, Paco; Rapp, Hans Tore; Boetius, Antje; Ramette, Alban
Zirconium alloys are well-known for their resistance to harsh chemical environments. In the interest of assessing the potential of this class of materials for bio-implant applications, we need to determine if this environmental stability transfers to biological systems. We report on our use of viable counts and infrared spectroscopic techniques to monitor how well thermally processed Zircaloy-2 surfaces resist bacterial
B. W. Buczynski; M. M. Kory; R. P. Steiner; T. A. Kittinger; R. D. Ramsier
Bile salts are surface-active steroid compounds. Their main physiological function is aiding the digestion of lipophilic nutrients\\u000a in intestinal tracts of vertebrates. Many bacteria are capable of transforming and degrading bile salts in the digestive tract\\u000a and in the environment. Bacterial bile salt transformation and degradation is of high ecological relevance and also essential\\u000a for the biotechnological production of steroid
\\u000a Functional bacterial amyloids constitute a group of important proteinaceous surface structures. Most amyloids are highly insoluble\\u000a in water and resistant to most enzymes and thermal and chemical denaturants. Their functions in bacteria are still not well\\u000a described but seem to include fimbriae and other cell appendages for adhesion and biofilm formation, cell envelope components,\\u000a spore coating, formation of large extracellular
Per Halkjćr Nielsen; Morten Simonsen Dueholm; Trine Rolighed Thomsen; Jeppe Lund Nielsen; Daniel Otzen
Bacterial cellulose was partially acetylated by the fibrous acetylationmethod to modify its physical properties, while preserving the microfibrillarmorphology. The overall degree of substitution was varied from 0.04 to 2.77 bychanging the amount of acetic anhydride added. X-ray diffraction of thepartially acetylated samples showed the crystalline pattern of unmodified celluloseI up to moderate degrees of acetylation, and the change in peak
Dae-Young Kim; Yoshiharu Nishiyama; Shigenori Kuga
Operons are sets of adjacent genes that encode proteins with related metabolic functions. Operon prediction may be useful\\u000a for understanding the systems of regulation and for genome annotation. In this work, we present an extension of the PROCSIMO\\u000a tool to allow the operon prediction in bacterial genomes based on the similarity evaluation between pairs of genes. Computational\\u000a experiments were made
Matheus B. S. Barros; Simone de L. Martins; Alexandre Plastino
\\u000a Polyhydroxyalkanoates (PHAs) are energy- and intracellular carbon-storage compounds that can be mobilized and used when carbon\\u000a is a limiting resource. Intracellular accumulation of PHA enhances the survival of several bacterial species under environmental\\u000a stress conditions imposed in water and soil, such as UV irradiation, salinity, thermal and oxidative stress, desiccation,\\u000a and osmotic shock. The ability to endure these stresses is
Susana Castro-Sowinski; Saul Burdman; Ofra Matan; Yaacov Okon
Motile bacteria respond to attractants and repellents in their environment by changing their movement. Stock et al. describe the similarities of the bacterial chemotaxis signaling system to eukaryotic signaling cascades. Also included is a discussion of how the ordered signaling complex of the receptor, the kinase CheA, and the kinase regulator CheW can be thought of as a primitive "probrain" to allow the integration of signals to produce the optimal cellular response.
Jeffry B. Stock (Princeton University;Department of Molecular Biology REV); Mikhail N. Levit (Princeton University;Department of Molecular Biology REV); Peter M. Wolanin (Princeton University;Department of Molecular Biology REV)
Bacterial vaginosis (BV) is a syndrome characterized by the loss of indigenous vaginal lactobacilli and massive polymicrobial\\u000a anaerobic vaginal overgrowth of elusive etiology. Although progress has occurred in defining the composition of the vaginal\\u000a microbiome using DNA amplifications, rapidly accumulating data have not resulted in therapeutic advantage. Treatment options\\u000a remain limited and outcome often unsatisfactory, particularly regarding the frequent recurrence
Jack D. Sobel
Bacterial vaginosis (BV) is an imbalance of vaginal flora. There is a statistical association between BV in early pregnancy and the occurrence of obstetric complications including preterm delivery. If screening and treatment of asymptomatic BV in patients at low risk are not recommended, the management of patients at high risk of prematurity is controversial. Using molecular tool, a rational and objective approach to the imbalance of vaginal flora, would reassess the relationship between VB and obstetric complications. PMID:22192689
Menard, J-P; Bretelle, F
Tongue piercing has become an increasingly popular form of body art. However, this procedure can occasionally be complicated by serious bacterial infections. The present article reports a case of prosthetic valve endocarditis caused by a Gemella species in a patient with a pierced tongue, and reviews 18 additional cases of local and systemic bacterial infections associated with tongue piercing. Infections localized to the oral cavity and head and neck region included molar abscess, glossal abscess, glossitis, submandibular lymphadenitis, submandibular sialadenitis, Ludwig’s angina and cephalic tetanus. Infections distal to the piercing site included eight cases of infective endocarditis, one case of chorioamnionitis and one case of cerebellar abscess. Oropharyngeal flora were isolated from all cases. While bacterial infections following tongue piercing are rare, there are reports of potentially life-threatening infections associated with the procedure. Both piercers and their clients should be aware of these potential complications, and standardized infection prevention and control practices should be adopted by piercers to reduce the risk.
Yu, Catherine HY; Minnema, Brian J; Gold, Wayne L
Genes are transferred between bacteria in dental plaque by transduction, conjugation, and transformation. Membrane vesicles can also provide a mechanism for horizontal gene transfer. DNA transfer is considered bacterial sex, but the transfer is not parallel to processes that we associate with sex in higher organisms. Several examples of bacterial gene transfer in the oral cavity are given in this review. How frequently this occurs in dental plaque is not clear, but evidence suggests that it affects a number of the major genera present. It has been estimated that new sequences in genomes established through horizontal gene transfer can constitute up to 30% of bacterial genomes. Gene transfer can be both inter- and intrageneric, and it can also affect transient organisms. The transferred DNA can be integrated or recombined in the recipient's chromosome or remain as an extrachromosomal inheritable element. This can make dental plaque a reservoir for antimicrobial resistance genes. The ability to transfer DNA is important for bacteria, making them better adapted to the harsh environment of the human mouth, and promoting their survival, virulence, and pathogenicity. PMID:23741559
Olsen, Ingar; Tribble, Gena D; Fiehn, Nils-Erik; Wang, Bing-Yan
A 57-year-old female patient with a history of tophaceous gout based on chronic renal insufficiency caused by systemic lupus erythematosus nephritis developed bursitis of the right lateral malleolus. This was taken for gout and was treated with colchicine and an increased dose of her maintenance therapy of oral glucocorticoids. Since this had no effect, a local diagnostic puncture was performed. Aspiration yielded pus from which Staphylococcus aureus was cultured; upon polarisation microscopy many uric acid crystals were seen. The diagnosis was gout and coincident bacterial infection. Therapy consisted of incision of the bursa and antibiotic therapy. Local recovery was uneventful. In patients suspected of an acute gout attack who have an increased risk of bacterial infection, e.g. elderly and patients with severe comorbidity or immunodeficiency, a local diagnostic aspiration is the only adequate investigation. Only if (coincident) bacterial infection has been ruled out, patients with contraindications for non-steroidal anti-inflammatory drug therapy and colchicine may safely be treated for a gout attack with oral glucocorticoids. PMID:20977804
Jacobs, Johannes W G; van Reekum, Franka
Naturally occurring gradients often extend over relatively long distances such that their steepness is too small for bacteria to detect. We studied the bacterial behavior in such thermal gradients. We find that bacteria migrate along shallow thermal gradients due to a change in their swimming speed resulting from the effect of temperature on the intracellular pH, which also depends on the chemical environment. When nutrients are scarce in the environment the bacteria's intracellular pH decreases with temperature. As a result, the swimming speed of the bacteria decreases with temperature, which causes them to slowly drift toward the warm end of the thermal gradient. However, when serine is added to the medium at concentrations >300 ?M, the intracellular pH increases causing the swimming speed to increase continuously with temperature, and the bacteria to drift toward the cold end of the temperature gradient. This directional migration is not a result of bacterial thermotaxis in the classical sense, because the steepness of the gradients applied is below the sensing threshold of bacteria. Nevertheless, our results show that the directional switch requires the presence of the bacterial sensing receptors. This seems to be due to the involvement of the receptors in regulating the intracellular pH.
Demir, Mahmut; Salman, Hanna
Bacteria respond to chemical cues by performing a biased random walk that enables them to migrate towards attractants and away from repellents. Bias is achieved by regulating the duration of the bacterial runs as a function of the environment, inferred from the history of chemoattractant detections experienced by the bacterium. This time-signal is processed using a time convolution function that can be assayed measuring the response of the bacterium to short pulses of chemoattractant. The convolution constitutes an elementary form of memory, which is encoded at the molecular level by the processes of (de-)methylation and (de-)phosphorylation of the underlying biochemical network. While the latter is being characterized in detail, the functional reasons shaping the bacterial chemotactic response are largely unknown. We show that the chemotactic response observed experimentally is the strategy that ensures the highest minimum (MaxiMin) uptake of chemoattractant, in any field thereof. The consequence is that adaptation of the chemotactic bacterial system appears to be evolutionary driven by the need to cope with space-time environmental fluctuations rather than the extension of the dynamic range of response.
To examine new cytochemical aspects of the bacterial adhesion, a strain 41452/01 of the oral commensal Streptococcus sanguis and a wild strain of Staphylococcus aureus were grown with and without sucrose supplementation for 6 days. Osmiumtetraoxyde (OsO4), uranyl acetate (UA), ruthenium red (RR), cupromeronic blue (CB) staining with critical electrolytic concentrations (CECs), and the tannic acid-metal salt technique (TAMST) were applied for electron microscopy. Cytochemically, only RR-positive fimbriae in S. sanguis were visualized. By contrast, some types of fimbriae staining were observed in S. aureus glycocalyx: RR-positive, OsO4-positive, tannophilic and CB-positive with ceasing point at 0.3 M MgCl2. The CB staining with CEC, used for the first time for visualization of glycoproteins of bacterial glycocalyx, also reveals intacellular CB-positive substances-probably the monomeric molecules, that is, subunits forming the fimbriae via extracellular assembly. Thus, glycosylated components of the biofilm matrix can be reliably related to single cells. The visualization of intracellular components by CB with CEC enables clear distinction between S. aureus and other bacteria, which do not produce CB-positive substances. The small quantities of tannophilic substances found in S. aureus makes the use of TAMST for the same purpose difficult. The present work protocol enables, for the first time, a partial cytochemical differentiation of the bacterial glycocalyx.
Krautgartner, Wolf Dietrich; Vitkov, Ljubomir; Hannig, Matthias; Pelz, Klaus; Stoiber, Walter
In 1994, the International Year of the Family, the WHO's Global Program on AIDS (GPA) is marking World AIDS Day under the banner AIDS and the Family. Traditional and non-traditional families have a crucial role to play in addressing the HIV/AIDS pandemic. In the run-up to World AIDS Day--and on 1 December itself--GPA urges the world to focus on how families of all kinds are affected by AIDS, on how they can be more effective in prevention and care, and on how they can contribute to global efforts against the disease. For GPA, any group of people linked by feelings of trust, mutual support and a common destiny may be seen as a family. The concept need not be limited to ties of blood, marriage, sexual partnership or adoption. In this light, religious congregations, workers' associations, support groups of people with HIV/AIDS, gangs of street children, circles of drug injectors, collectives of sex workers and networks of governmental, nongovernmental and intergovernmental organizations may all be regarded as families within the over-arching family of humankind. Every kind of family should take care to protect its members from HIV. And all families should take care of those among them who fall ill with AIDS. Families take care. "Families whose bonds are based on love, trust, nurturing and openness are best placed to protect their members from infection and give compassionate care and support to those affected by HIV or AIDS," says Dr. Hiroshi Nakajima, Director-General of the WHO [World Health Organization]. PMID:12287963
The Lrp\\/AsnC family of transcriptional regulatory proteins is found in both archaea and bacteria. Members of the family influence cellular metabolism in both a global (Lrp) and specific (AsnC) manner, often in response to exogenous amino acid effectors. In the present study we have determined both the first bacterial and the highest resolution structures for members of the family. Escherichia
Paul Thaw; Svetlana E. Sedelnikova; Tatyana Muranova; Sebastian Wiese; Sylvia Ayora; Juan C. Alonso; Arie B. Brinkman; A. P. Akerboom; John van der Oost; John B. Rafferty
The crystal structure of the enzyme phosphoglucomutase from Salmonella typhimurium (StPGM) is reported at 1.7 Ĺ resolution. This is the first high-resolution structural characterization of a bacterial protein from this large enzyme family, which has a central role in metabolism and is also important to bacterial virulence and infectivity. A comparison of the active site of StPGM with that of other phosphoglucomutases reveals conserved residues that are likely involved in catalysis and ligand binding for the entire enzyme family. An alternate crystal form of StPGM and normal mode analysis give insights into conformational changes of the C-terminal domain that occur upon ligand binding. A novel observation from the StPGM structure is an apparent dimer in the asymmetric unit of the crystal, mediated largely through contacts in an N-terminal helix. Analytical ultracentrifugation and small-angle X-ray scattering confirm that StPGM forms a dimer in solution. Multiple sequence alignments and phylogenetic studies show that a distinct subset of bacterial PGMs share the signature dimerization helix, while other bacterial and eukaryotic PGMs are likely monomers. These structural, biochemical, and bioinformatic studies of StPGM provide insights into the large ?-d-phosphohexomutase enzyme superfamily to which it belongs, and are also relevant to the design of inhibitors specific to the bacterial PGMs.
Mehra-Chaudhary, Ritcha; Mick, Jacob; Tanner, John J.; Henzl, Michael T.; Beamer, Lesa J.
This study examined the effectiveness of a culturally adapted Strengthening Families Program (SFP) for Latinos to reduce risks for alcohol and drug use in children. Latino families, predominantly Puerto Rican, with a 9- to 12-year-old child and a parent(s) with a substance abuse problem participated in the study. Pre- and post-tests were conducted…
Chartier, Karen G.; Negroni, Lirio K.; Hesselbrock, Michie N.
A consideration of interactional style is useful to both researchers and clinicians interested in family assessment. This paper offers data and process evaluation scales designed to determine family interactional style, conceptualized as a continuum ranging from centripetal (CP) to centrifugal (CF), and containing at the midpoint a mixed area in which facets of both the CP and the CF styles
Martha Kelsey-smith; W. Robert Beavers M. D
Background Outer membrane vesicles (OMVs) are constitutively produced by Gram-negative bacteria throughout growth and have proposed roles in virulence, inflammation, and the response to envelope stress. Here we investigate outer membrane vesiculation as a bacterial mechanism for immediate short-term protection against outer membrane acting stressors. Antimicrobial peptides as well as bacteriophage were used to examine the effectiveness of OMV protection. Results We found that a hyper-vesiculating mutant of Escherichia coli survived treatment by antimicrobial peptides (AMPs) polymyxin B and colistin better than the wild-type. Supplementation of E. coli cultures with purified outer membrane vesicles provided substantial protection against AMPs, and AMPs significantly induced vesiculation. Vesicle-mediated protection and induction of vesiculation were also observed for a human pathogen, enterotoxigenic E. coli (ETEC), challenged with polymyxin B. When ETEC with was incubated with low concentrations of vesicles concomitant with polymyxin B treatment, bacterial survival increased immediately, and the culture gained resistance to polymyxin B. By contrast, high levels of vesicles also provided immediate protection but prevented acquisition of resistance. Co-incubation of T4 bacteriophage and OMVs showed fast, irreversible binding. The efficiency of T4 infection was significantly reduced by the formation of complexes with the OMVs. Conclusions These data reveal a role for OMVs in contributing to innate bacterial defense by adsorption of antimicrobial peptides and bacteriophage. Given the increase in vesiculation in response to the antimicrobial peptides, and loss in efficiency of infection with the T4-OMV complex, we conclude that OMV production may be an important factor in neutralizing environmental agents that target the outer membrane of Gram-negative bacteria.
Magnesium is an essential divalent metal that serves many cellular functions. While most divalent cations are maintained at relatively low intracellular concentrations, magnesium is maintained at a higher level (?0.5–2.0 mM). Three families of transport proteins were previously identified for magnesium import: CorA, MgtE, and MgtA/MgtB P-type ATPases. In the current study, we find that expression of a bacterial protein unrelated to these transporters can fully restore growth to a bacterial mutant that lacks known magnesium transporters, suggesting it is a new importer for magnesium. We demonstrate that this transport activity is likely to be specific rather than resulting from substrate promiscuity because the proteins are incapable of manganese import. This magnesium transport protein is distantly related to the Nramp family of proteins, which have been shown to transport divalent cations but have never been shown to recognize magnesium. We also find gene expression of the new magnesium transporter to be controlled by a magnesium-sensing riboswitch. Importantly, we find additional examples of riboswitch-regulated homologues, suggesting that they are a frequent occurrence in bacteria. Therefore, our aggregate data discover a new and perhaps broadly important path for magnesium import and highlight how identification of riboswitch RNAs can help shed light on new, and sometimes unexpected, functions of their downstream genes.
Rodionov, Dmitry A.; Freedman, Benjamin G.; Senger, Ryan S.; Winkler, Wade C.
Reversible phosphorylation is a widespread modification affecting the great majority of eukaryotic cellular proteins, and whose effects influence nearly every cellular function. Protein phosphatases are increasingly recognized as exquisitely regulated contributors to these changes. The PPP (phosphoprotein phosphatase) family comprises enzymes, which catalyze dephosphorylation at serine and threonine residues. Nearly a decade ago, "bacterial-like" enzymes were recognized with similarity to proteins from various bacterial sources: SLPs (Shewanella-like phosphatases), RLPHs (Rhizobiales-like phosphatases), and ALPHs (ApaH-like phosphatases). A recent article from our laboratory appearing in Plant Physiology characterizes their extensive organismal distribution, abundance in plant species, predicted subcellular localization, motif organization, and sequence evolution. One salient observation is the distinct evolutionary trajectory followed by SLP genes and proteins in photosynthetic eukaryotes vs. animal and plant pathogens derived from photosynthetic ancestors. We present here a closer look at sequence data that emphasizes the distinctiveness of pathogen SLP proteins and that suggests that they might represent novel drug targets. A second observation in our original report was the high degree of similarity between the bacterial-like PPPs of eukaryotes and closely related proteins of the "eukaryotic-like" phyla Myxococcales and Planctomycetes. We here reflect on the possible implications of these observations and their importance for future research. PMID:24675170
Kerk, David; Uhrig, R Glen; Moorhead, Greg B
Recent studies have unravelled the diversity of sponge-associated bacteria that may play essential roles in sponge health and metabolism. Nevertheless, our understanding of this microbiota remains limited to a few host species found in restricted geographical localities, and the extent to which the sponge host determines the composition of its own microbiome remains a matter of debate. We address bacterial abundance and diversity of two temperate marine sponges belonging to the Irciniidae family - Sarcotragus spinosulus and Ircinia variabilis – in the Northeast Atlantic. Epifluorescence microscopy revealed that S. spinosulus hosted significantly more prokaryotic cells than I. variabilis and that prokaryotic abundance in both species was about 4 orders of magnitude higher than in seawater. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) profiles of S. spinosulus and I. variabilis differed markedly from each other – with higher number of ribotypes observed in S. spinosulus – and from those of seawater. Four PCR-DGGE bands, two specific to S. spinosulus, one specific to I. variabilis, and one present in both sponge species, affiliated with an uncultured sponge-specific phylogenetic cluster in the order Acidimicrobiales (Actinobacteria). Two PCR-DGGE bands present exclusively in S. spinosulus fingerprints affiliated with one sponge-specific phylogenetic cluster in the phylum Chloroflexi and with sponge-derived sequences in the order Chromatiales (Gammaproteobacteria), respectively. One Alphaproteobacteria band specific to S. spinosulus was placed in an uncultured sponge-specific phylogenetic cluster with a close relationship to the genus Rhodovulum. Our results confirm the hypothesized host-specific composition of bacterial communities between phylogenetically and spatially close sponge species in the Irciniidae family, with S. spinosulus displaying higher bacterial community diversity and distinctiveness than I. variabilis. These findings suggest a pivotal host-driven effect on the shape of the marine sponge microbiome, bearing implications to our current understanding of the distribution of microbial genetic resources in the marine realm.
Hardoim, Cristiane C. P.; Esteves, Ana I. S.; Pires, Francisco R.; Goncalves, Jorge M. S.; Cox, Cymon J.; Xavier, Joana R.; Costa, Rodrigo
Symbiotic relationships between microbes and plants are common and well studied in terrestrial ecosystems, but little is known about such relationships in aquatic environments. We compared the phylogenetic diversities of leaf- and root-attached bacteria from four species of aquatic angiosperms using denaturing gradient gel electrophoresis (DGGE) and DNA sequencing of PCR-amplified 16S rRNA genes. Plants were collected from three beds in Chesapeake Bay at sites characterized as freshwater (Vallisneria americana), brackish (Potomogeton perfoliatus and Stuckenia pectinata), and marine (Zostera marina). DGGE analyses showed that bacterial communities were very similar for replicate samples of leaves from canopy-forming plants S. pectinata and P. perfoliatus and less similar for replicate samples of leaves from meadow-forming plants Z. marina and V. americana and of roots of all species. In contrast, bacterial communities differed greatly among plant species and between leaves and roots. DNA sequencing identified 154 bacterial phylotypes, most of which were restricted to single plant species. However, 12 phylotypes were found on more than one plant species, and several of these phylotypes were abundant in clone libraries and represented the darkest bands in DGGE banding patterns. Root-attached phylotypes included relatives of sulfur-oxidizing Gammaproteobacteria and sulfate-reducing Deltaproteobacteria. Leaf-attached phylotypes included relatives of polymer-degrading Bacteroidetes and phototrophic Alphaproteobacteria. Also, leaves and roots of three plant species hosted relatives of methylotrophic Betaproteobacteria belonging to the family Methylophilaceae. These results suggest that aquatic angiosperms host specialized communities of bacteria on their surfaces, including several broadly distributed and potentially mutualistic bacterial populations.
Crump, Byron C.; Koch, Evamaria W.
Recent studies have revealed a distinct class of bacterial effectors defined by the presence of EPIYA or EPIYA-related motif. These bacterial EPIYA effectors are delivered into host cells via type III or IV secretion, where they undergo tyrosine phosphorylation at the EPIYA motif and thereby manipulate host signalling by promiscuously interacting with multiple SH2 domain-containing proteins. Up to now, nine EPIYA effectors have been identified from various bacteria. These effectors do not share sequence homology outside the EPIYA motif, arguing against the idea that they have common ancestors. A search of mammalian proteomes revealed the presence of a mammalian EPIYA-containing protein, Pragmin, which potentiates Src family kinase (SFK) activity by binding and sequestrating the SFK inhibitor Csk upon EPIYA phosphorylation. As several bacterial EPIYA effectors also target Csk, they may have evolved through generation of sequences that mimic the Pragmin EPIYA motif. EPIYA motifs are often diverged through multiple duplications in each bacterial effector. Such a structural plasticity appears to be due to intrinsic disorder of the EPIYA-containing region, which enables the bacterial effectors to undergo efficient phosphorylation and mediate promiscuous interaction with multiple host proteins. Given the functional versatility of the EPIYA motif, many more bacterial EPIYA effectors will soon be emerging. PMID:23051602
Hayashi, Takeru; Morohashi, Hiroko; Hatakeyama, Masanori
Microbial infection is a critical source of mortality for early life stages of oviparous vertebrates, but parental defenses against infection are less well known. Avian incubation has been hypothesized to reduce the risk of trans-shell infection by limiting microbial growth of pathogenic bacteria on eggshells, while enhancing growth of commensal or beneficial bacteria that inhibit or competitively exclude pathogens. We tested this hypothesis by comparing bacterial assemblages on naturally incubated and experimentally unincubated eggs at laying and late incubation using a universal 16S rRNA microarray containing probes for over 8000 bacterial taxa. Before treatment, bacterial assemblages on individual eggs from both treatment groups were dissimilar to one another, as measured by clustering in non-metric dimensional scaling (NMDS) ordination space. After treatment, assemblages of unincubated eggs were similar to one another, but those of incubated eggs were not. Furthermore, assemblages of unincubated eggs were characterized by high abundance of six indicator species while incubated eggs had no indicator species. Bacterial taxon richness remained static on incubated eggs, but increased significantly on unincubated eggs, especially in several families of Gram-negative bacteria. The relative abundance of individual bacterial taxa did not change on incubated eggs, but that of 82 bacterial taxa, including some known to infect the interior of eggs, increased on unincubated eggs. Thus, incubation inhibits all of the relatively few bacteria that grow on eggshells, and does not appear to promote growth of any bacteria.
Shawkey, Matthew D.; Firestone, Mary K.; Brodie, Eoin L.; Beissinger, Steven R.
... PolicyDigest Newsletter Caregiver Connect SF Bay Area Services Family Care Navigator Research Registry Support Groups Caregiver Stories ... Asked Questions Professional Inquiry Form Publication Order Form Family Caregiver Alliance supports and sustains the important work ...
Explored Rokeach's theory that dogmatism develops within the family. Subjects were college students and their parents who took the 40-item Dogmatism Scale. Results indicated that family experiences are one source of children's dogmatism but not the only source. (SDH)
Lesser, Harvey; Steininger, Marion
A major concern with the Space Station Freedom (SSF) water supply system is the control of longterm microbial contamination and biofilm development in the water storage and distribution systems. These biofilms have the potential for harboring pathogens as well as microbial strains containing resistance factors that could negatively influence crew health. The proposed means for disinfecting the water system on SSF (iodine) may encourage the selection of resistant strains. In fact, biofilm bacteria were observed in water lines from the Space Shuttle Columbia (OV-102); therefore, an alternative remediation method is required to disinfect spacecraft water lines. A thorough understanding of colonization events and the physiological parameters that will influence bacteria adhesion is required. The limiting factor for development of this technology is the ability to continuously monitor adhesion events and the effects of biocides on sessile bacteria. Methods were developed to allow bacterial adhesion and subsequent biocidal treatment to be monitored continuously. This technique couples automated image analysis with a continuous flow of a bacterial suspension through an optical flow cell. A strain of Pseudomonas cepacia isolated from the water supply of the Space Shuttle Discovery (OV-103) during STS-39 was grown in a nitrogen-limited continuous culture. This culture was challenged continuously with iodine during growth, and the adhesion characteristics of this strain was measure with regard to flow rate. Various biocides (ozone, hypochlorite, and iodine) were added to the flow stream to evaluate how well each chemical removed the bacteria. After biocide treatment, a fresh bacterial suspension was introduced into the flow cell, and the attachment rate was evaluated on the previously treated surface. This secondary fouling was again treated with biocide to determine the efficacy of multiple batch chemical treatments in removing biofilm.
Koeing, D. W.; Mishra, S. K.; Pierson, D. L.
The membranes of eukaryotic cells harbor microdomains known as lipid rafts that contain a variety of signaling and transport proteins. Here we show that bacterial membranes contain microdomains functionally similar to those of eukaryotic cells. These membrane microdomains from diverse bacteria harbor homologs of Flotillin-1, a eukaryotic protein found exclusively in lipid rafts, along with proteins involved in signaling and transport. Inhibition of lipid raft formation through the action of zaragozic acid--a known inhibitor of squalene synthases--impaired biofilm formation and protein secretion but not cell viability. The orchestration of physiological processes in microdomains may be a more widespread feature of membranes than previously appreciated. PMID:20713508
López, Daniel; Kolter, Roberto
The membranes of eukaryotic cells harbor microdomains known as lipid rafts that contain a variety of signaling and transport proteins. Here we show that bacterial membranes contain microdomains functionally similar to those of eukaryotic cells. These membrane microdomains from diverse bacteria harbor homologs of Flotillin-1, a eukaryotic protein found exclusively in lipid rafts, along with proteins involved in signaling and transport. Inhibition of lipid raft formation through the action of zaragozic acid—a known inhibitor of squalene synthases—impaired biofilm formation and protein secretion but not cell viability. The orchestration of physiological processes in microdomains may be a more widespread feature of membranes than previously appreciated.
Lopez, Daniel; Kolter, Roberto
Periodontitis is a widespread disease that appears to be due to a specific bacterial infection. Several species of bacteria have been investigated as potential pathogens, and particularly strong evidence links the presence of Porphyromonas gingivalis with indicators of periodontitis. Information concerning the transmission of P. gingivalis between human contacts may be important in determining risk factors for disease and developing preventive strategies. A few small studies have provided some evidence of transmission between related individuals, but no large-scale study of families that would reflect the typical transmission of this pathogen in the population has been reported. The purpose of this study was to investigate the transmission of P. gingivalis within randomly selected, extended families. The colonization status of 564 members of multigeneration families was determined, and the degree of concordance observed among members of these families was then compared to that expected to occur based on the prevalence of colonization in the population studied. A PCR assay was used for detection of P. gingivalis. Concordance in colonization was more frequently observed within entire families (P = 0.0000) and for spouses (P < 0.001), children and their mothers (P < 0.001), children and their fathers (P < 0.01), adults and their mothers (P < 0.005), and siblings (P < 0.05) than would be expected if P. gingivalis were randomly distributed in the population studied. Results showed that contact with an infected family member substantially increased the relative risk of colonization in these intrafamilial pairs. This indicates that P. gingivalis is commonly transmitted by contact with an infected family member.
Tuite-McDonnell, M; Griffen, A L; Moeschberger, M L; Dalton, R E; Fuerst, P A; Leys, E J
Fabry disease (FD) is a rare disorder resulting from mutations of the alpha-Galactosidase A lysosomal enzyme gene. Accumulation of enzyme substrates leads to multisystemic clinical manifestations and multiorgan progressive damage with high morbidity and mortality. Recombinant enzyme replacement therapy (RERT) now available aims to delay or even avoid the complications of FD. The index case was a 50-year-old man with bone pain since childhood, coarse facies, angiokeratomas, anemia, renal failure, proteinuria, sinus node disease, valvular disease and massive left ventricular hypertrophy and brain ischemic alterations. FD diagnosis was confirmed during hospital admission for bacterial endocarditis leading to death. Family screening revealed an affected brother with acroparesthesia, chronic cough, sinus bradycardia, long QT interval and near-nephrotic proteinuria, now under RERT. Their mother was not screened due to stroke sequelae. This report illustrates the need for early diagnosis, family screening and treatment, aiming to change the natural history of FD. PMID:20654270
Capelo, Joana; Soares, Carlos; Carragoso, Adelino; Ribeiro, Pedro; Girăo, Fernando; Henriques, Pedro
Colonies of bacteria grown on thin agar plate exhibit fractal patterns as a result of adaptation to their environments. The bacterial colony pattern formation is regulated crucially by chemotaxis, the movement of cells along a chemical concentration gradient. Here, the dynamics of pattern formation in a bacterial colony is investigated theoretically through a continuum model that considers chemotaxis. In the case of the gradient sensed by the bacterium is nearly uniform, the bacterial colony patterns are self-similar, which means they look the same at every scale. The scaling law of the bacterial colony growth has been revealed explicitly. Chemotaxis biases the movement of the bacterial population in colony to trend toward the chemical attractant. Moreover, the bacterial colonies evolve for a long time as the traveling wave with a sharp front.
Ngamsaad, Waipot; Khompurngson, Kannika
Background The work presented here provides the first intensive insight into the bacterial populations in the digestive tract of the North American moose (Alces alces). Eight free-range moose on natural pasture were sampled, producing eight rumen samples and six colon samples. Second generation (G2) PhyloChips were used to determine the presence of hundreds of operational taxonomic units (OTUs), representing multiple closely related species/strains (>97% identity), found in the rumen and colon of the moose. Results A total of 789 unique OTUs were used for analysis, which passed the fluorescence and the positive fraction thresholds. There were 73 OTUs, representing 21 bacterial families, which were found exclusively in the rumen samples: Lachnospiraceae, Prevotellaceae and several unclassified families, whereas there were 71 OTUs, representing 22 bacterial families, which were found exclusively in the colon samples: Clostridiaceae, Enterobacteriaceae and several unclassified families. Overall, there were 164 OTUs that were found in 100% of the samples. The Firmicutes were the most dominant bacteria phylum in both the rumen and the colon. Microarray data available at ArrayExpress, accession number E-MEXP-3721. Conclusions Using PhyloTrac and UniFrac computer software, samples clustered into two distinct groups: rumen and colon, confirming that the rumen and colon are distinct environments. There was an apparent correlation of age to cluster, which will be validated by a larger sample size in future studies, but there were no detectable trends based upon gender.
Major changes are taking place in American and Cana- dian families exerting dramatic influences on family life and the pro- fessional of nursing. This was a recently completed project involving a multidisciplinary team of scholars from across North America that brought together the latest information available on a wide variety of single parent families. The purpose of this chapter is
Shirley M. H. Hanson; Marsha L. Heims; Doris J. Julian; Marvin B. Sussman
Purpose: Despite growing research on assisted living (AL) as a residential care option for older adults, the social ramifications of residents' transitions to AL are relatively unexplored. This article examines family involvement in AL, including family structures of residents, types of involvement from family members living outside the AL…
Gaugler, Joseph E.; Kane, Robert L.
All OECD governments want to give parents more choice in their work and family decisions. This book looks at the different ways in which governments support families. It seeks to provide answers to questions like: Is spending on family benefits going up, and how does it vary by the age of the child? Has the crisis affected public support for…
OECD Publishing (NJ3), 2011
This paper explores how single mothers both incorporate others into family life (e.g., when they ask others to care for their children) and simultaneously "do families" in a manner that holds out a vision of a "traditional" family structure. Drawing on research with White, rural single mothers, the author explores the manner in which these women…
Nelson, Margaret K.
This special issue focuses on problems and challenges confronting the California family and on research and extension efforts to provide at least partial answers. Research briefs by staff include "Challenges Confront the California Family" (state trends in poverty, divorce, single-parent families, child abuse, delinquency, teen births, limited…
California Agriculture, 1994
This document is designed to help literacy practitioners and others promote and establish family literacy programs to prepare adult learners in South Carolina for their roles as parents, workers, health consumers, and citizens. The rationale for promoting family literacy is explained. The following topics are discussed: a design for family…
Campbell, Dottie C.; Wilson, Kathleen
Improving parenting practices and the family environment is the most effective, enduring strategy for combating juvenile delinquency. Describes the Office of Juvenile Justice and Delinquency Prevention's Strengthening America's Families Initiative. Highlights several family-focused prevention programs identified as exemplary, explaining how they…
Alvarado, Rose; Kumpfer, Karol
The past decade has brought changes in our understanding of family businesses. This article identifies 10 “megatrends,” which are evolving changes fundamental to understanding and working with family businesses. Identified trends include focusing on generational transitions rather than business succession; team management and ownership as a developing norm; the increasing importance of strategic planning in family business; increasing financial sophistication;
Craig E. Aronoff
This lesson introduces Family Message Journals, a tool for encouraging family involvement and supporting writing to reflect and learn. First and second graders are led into composing through demonstration, guided writing, and finally independent writing of messages that they will bring home for family to read and write a reply. During the three…
Recognizing the importance of maintaining open communication with immediate and extended family members, this book provides a compilation of ideas for family traditions and customs that are grounded in compassion and human kindness. The traditions were gathered from families in the United States and Canada who responded to advertisements in…
Examines religion's place in the social sciences, reciprocal influences of family and religion, cohesion/polarization in American Catholic families, religion in Middletown, USA, gender and religion in Canadian and American students, domestic/religious individualism and suicide, and the New Christian Right's view of the family. (BH)
Thomas, Darwin L., Ed.
Provides an overview of marriage and family counseling, including the growth of interest in this specialty within the American Counseling Association (ACA). Discusses the evolution of marriage and family counseling within ACA, standards for training, credentialing, and unique ethical considerations when counseling couples and families. (Author)
Smith, Robert L.; And Others
An association of families of children with leukemia, the Family Leukemia Association (FLA), was recently established in Toronto. This paper discusses (a) philosophy of the FLA; (b) formative years of this organization; (c) problems encountered by leukemic children and their families; and (d) the FLA's past and future educational and social…
Kenyon College's Family Farm Project, "a three-year study exploring family farming and community life in Knox County, Ohio," presents an intimate multimedia view of the daily life of the family farm, which some consider a vanishing institution in America.
The Family Resource Coalition of America (FRCA) and the National Resource Center for Family Centered Practice convened a meeting of evaluators, policymakers, and program practitioners to discuss the issue of evaluation in the field of family support. The goal was to bring together those who were implementing programs, evaluating programs, and…
Lalley, Jacqueline, Ed.; Ahsan, Nilofer, Ed.
Covering contemporary Third World as well as Western families, this teaching text addresses topics essential for developing a multicultural perspective on the family. It is an ideal text for comparative family courses and includes exercises (as well as exercise guidelines for instructors) developed to challenge students' existing viewpoints and…
Ingoldsby, Bron B., Ed.; Smith, Suzanna, Ed.
This issue of "Emphasis" deals with families in transition, providing some model programs for the new family and some historical perspectives on how families have developed over time. Articles include: (1) "Nostalgia on the Right" (Nancy Theriot); (2) "Heart to Heart" (Nancy Harrington-MacLennan); (3) "The Media Get the Message" (Janet Alyn); (4)…
Britton, Patti O., Ed.; McGee, Michael, Ed.
This presentation reviews the characteristics of the Canadian family at present. Discussion focuses on divorce, family structure, reproductive technology, fertility, family size, family mobility, family support, government role, women's participation in the labor force, daily family routines, television viewing, work and the family, the need for…
A pharmaceutical composition in a preferred embodiment comprises an isolated bacterial protein that induces fibrin-dependent plasminogen activation, and methods for dissolving blood clots in a subject use such a composition. Embodiments also include a nucleic acid encoding such a bacterial protein, a nucleic acid encoding such a bacterial protein as a fusion to another protein, an expression vector with the nucleic acid, and a host cell transformed with the expression vector.
AIMSTo report the clinical findings and visual outcome of patients with extended wear contact lens (EWCL) related bacterial keratitis.METHODS11 cases with EWCL related bacterial keratitis were included. Corneal scrapings were obtained for cytology and cultures.RESULTSNine patients had unilateral bacterial keratitis and two patients showed bilateral involvement. Corneal scrapings revealedPseudomonas aeruginosa in seven patients, Staphylococcus aureus coagulase positive in one patient,
Khalid F Tabbara; Hisham F El-Sheikh; Bassam Aabed
AIMS—To report the clinical findings and visual outcome of patients with extended wear contact lens (EWCL) related bacterial keratitis.?METHODS—11 cases with EWCL related bacterial keratitis were included. Corneal scrapings were obtained for cytology and cultures.?RESULTS—Nine patients had unilateral bacterial keratitis and two patients showed bilateral involvement. Corneal scrapings revealed Pseudomonas aeruginosa in seven patients, Staphylococcus aureus coagulase positive in one patient, and Staphylococcus epidermidis in three patients.?CONCLUSION—EWCLs may be associated with bacterial keratitis and may result in visual loss. Dispensing contact lenses by optometrists should be performed in consultation with ophthalmologists.??
Tabbara, K.; El-Sheikh, H.; Aabed, B.
Swarming is a widespread phenomenon observed in both biological and non-biological systems. Large mammal herds, fish schools, and bird flocks are among the most spectacular examples. Many theoretical and numerical efforts have been made to unveil the general principles of the phenomenon, but systematic experimental studies have been very limited. We determine the characteristic velocity, length, and time scales for bacterial motion in swarming colonies of Paenibacillus dendritiformis growing on semi-solid agar substrates. The bacteria swim within a thin fluid layer, and they form long-lived jets and vortices. These coherent structures lead to anisotropy in velocity spatial correlations and to a two-step relaxation in velocity temporal correlations. The mean squared displacement of passive tracers exhibits a short-time regime with nearly ballistic transport and a diffusive long-time regime. We find that various definitions of the correlation length all lead to length scales that are, surprisingly, essentially independent of the mean bacterial speed, while the correlation time is linearly proportional to the ratio of the correlation length to the mean speed.
Zhang, Hepeng; Be'Er, Avraham; Smith, Rachel; Florin, E.-L.; Swinney, Harry L.
The use of chromophore dyes to enhance the bactericidal effect of laser energy was studied as a means to optimize laser treatment for the decontamination of wound. Using an in vitro study, various concentrations of indocyanine green (ICG), carbon black, and fluorescein were mixed with a suspension of bacteria and plated on tryptic soy agar. Plates were exposed to a laser beam of 10-15 watts for times ranging from 0 to 180 seconds, incubated overnight, and colony counts were performed. Bacteria not mixed with chromophore were used as controls. Six bacterial strains encompassing a range of bacterial types were used: Staphylococcus aureau, Streptococcus pyogenes, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus spore suspensions, and Clostridium perfringens. Laser treatment alone had no effect on any of the bacteria. Significant killing of gram-positive bacteria, including spores of Bacillus cereus, was observed only with the use of ICG and diode laser energy. No effect was observed using any of the chromophores on the gram-negative bacteria. The results of this study indicate that successful killing of gram-positive bacteria can be achieved using ICG combined with appropriate laser energy and wavelength. Efforts to enhance the susceptibility of gram-negative bacteria to photothermolysis by laser energy were unsuccessful.
Huckleby, Jana K.; Morton, Rebecca J.; Bartels, Kenneth E.
Recent progress in studies on the bacterial chromosome is summarized. Although the greatest amount of information comes from studies on Escherichia coli, reports on studies of many other bacteria are also included. A compilation of the sizes of chromosomal DNAs as determined by pulsed-field electrophoresis is given, as well as a discussion of factors that affect gene dosage, including redundancy of chromosomes on the one hand and inactivation of chromosomes on the other hand. The distinction between a large plasmid and a second chromosome is discussed. Recent information on repeated sequences and chromosomal rearrangements is presented. The growing understanding of limitations on the rearrangements that can be tolerated by bacteria and those that cannot is summarized, and the sensitive region flanking the terminator loci is described. Sources and types of genetic variation in bacteria are listed, from simple single nucleotide mutations to intragenic and intergenic recombinations. A model depicting the dynamics of the evolution and genetic activity of the bacterial chromosome is described which entails acquisition by recombination of clonal segments within the chromosome. The model is consistent with the existence of only a few genetic types of E. coli worldwide. Finally, there is a summary of recent reports on lateral genetic exchange across great taxonomic distances, yet another source of genetic variation and innovation.
Krawiec, S; Riley, M
An in vitro system was developed to study the migration of uropathogenic Escherichia coli strains. In this system an aqueous agar gel is placed against a solid surface, allowing the bacteria to migrate along the gel/solid surface interface. Bacterial strains as well as solid surfaces were characterized by means of water contact angle and zeta potential measurements. When glass was used as the solid surface, significantly different migration times for the strains investigated were observed. Relationships among the observed migration times of six strains, their contact angles, and their zeta potentials were found. Relatively hydrophobic strains exhibited migration times shorter than those of hydrophilic strains. For highly negatively charged strains shorter migration times were found than were found for less negatively charged strains. When the fastest-migrating strain with respect to glass was allowed to migrate along solid surfaces differing in hydrophobicity and charge, no differences in migration times were found. Our findings indicate that strategies to prevent catheter-associated bacteriuria should be based on inhibition of bacterial growth rather than on modifying the physicochemical character of the catheter surface.
Harkes, G; Dankert, J; Feijen, J
The populations of six bacterial genera fell rapidly after their addition to sterile lake water but not after their addition to buffer. The decline in numbers of two species that were studied further, Klebsiella pneumoniae and Micrococcus flavus, occurred even when the buffer was added to sterile lake water. The inhibition of K. pneumoniae by substances in lake water varied with the season of the year, and the rate and extent of decline of both species were different in sterile samples of different lakes. The extent of reduction in the density of K. pneumoniae was independent of initial population size and was diminished by the addition of 10 ?g of glucose per ml of lake water. The toxin was removed from lake water by dialysis and by a cation-exchange resin but not by an anion-exchange resin, and it was destroyed by heating. The inhibition of K. pneumoniae was not evident in lake water buffered at a pH value above 8.0. We suggest that toxins may be important in determining the composition of the bacterial community of lakes.
Klein, Theodore M.; Alexander, Martin
Natural and anthropogenic salinization continuously impacts inland aquatic ecosystems. Associated bacterial biofilms respond rapidly to environmental conditions and are potential bioindicators for changes in water quality. This study evaluates the effects of different salinity concentrations (0.3‰-10‰) on bacterial biofilms communities grown in fresh water from Lake Bosten. Bacterial communities associated with biofilms were analyzed using terminal restriction fragment length polymorphism and clone library analyses of 16S rRNA genes. Results indicated that the attached bacterial community composition (ABCC) changed over several weeks of biofilm growth, but all followed similar bacterial successional trends in the different salinity groups. Detailed analysis showed the following. (i) ABCC did not differ (P > 0.05) in the low-salinity groups (0.3‰-3.5‰), which may be related to the lower osmotic pressure and the shorter time scale (weeks) of their present habitats. (ii) There were significant differences between the oligosaline (3.5‰) and saline (10‰) groups (P < 0.05). In particular, genus Flavobacterium became dominant in attached bacterial communities in the saline groups. The higher abundance of genus Flavobacterium was possibly due to the biological and metabolic characteristics of the bacteria. (iii) Some bacterial taxa can maintain the higher abundance within attached bacteria in the entire process of biofilms growth, such as the genera Hydrogenophaga and Methyloversatilis in Betaproteobacteria and the family Sphingomonadaceae in Alphaproteobacteria. These data suggested that the bacterial successional trends within biofilms seem almost unaffected by salinity (0.3‰-10‰), but ABCC in saline groups (10‰) are notably changed. PMID:24802939
Zhang, Lei; Gao, Guang; Tang, Xiangming; Shao, Keqiang
The transposase of IS911, a member of the IS3 family of bacterial insertion sequences, is com- posed of a catalytic domain located at its C-terminal end and a DNA binding domain located at its N-terminal end. Analysis of the transposases of over 60 members of the IS3 family revealed the pres- ence of a helix-turn-helix (HTH) motif within the N-terminal
Philippe Rousseau; Erwan Gueguen; Guy Duval-Valentin; Mick Chandler
The national project 'Transformation in Health' was started in 2005 to provide expert primary care by family physicians, and decrease expenses in Turkey. The number of family physicians was far below the need, so public physicians were promoted to family physician status after a 10-day intensive course. The government declared some satisfactory results, but privately paid family physicians were not accepted into the system. Furthermore, the government stopped paying for their services from private settings. Some family physicians became unemployed as the major payer for all forms of medical care in Turkey denied their services. The process showed it's value in time. Nevertheless, family physicians should be the core of this transformation as family medicine is an academic and a scientific discipline and a primary care-oriented specialty with its own specific educational content, research and base of evidence, which cannot be achieved through standard medical education. PMID:24682837
Ozsahin, Akatli Kursad
In this study, we conduct potentiometric titrations and metal adsorption experiments (Cd, Ca, Cu, Pb, Sr, and Zn) using bacterial consortia grown from three representative locations and sampled over the course of a year in order to determine whether bacterial diversity affects proton and metal uptake behaviors. We observe significant changes in bacterial diversity from one site to another, and
Kelly J. Johnson; Jennifer E. S. Szymanowski; David Borrok; Terri Q. Huynh; Jeremy B. Fein
Proteins in the cupin superfamily have a wide range of biological functions in archaea, bacteria and eukaryotes. Although proteins in the cupin superfamily show very low overall sequence similarity, they all contain two short but partially conserved cupin sequence motifs separated by a less conserved intermotif region that varies both in length and amino acid sequence. Furthermore, these proteins all share a common architecture described as a six-stranded ?-barrel core, and this canonical cupin or "jelly roll" ?-barrel is formed with cupin motif 1, the intermotif region, and cupin motif 2 each forming two of the core six ?-strands in the folded protein structure. The recently obtained crystal structures of cysteine dioxygenase (CDO), with contains conserved cupin motifs, show that it has the predicted canonical cupin ?-barrel fold. Although there had been no reports of CDO activity in prokaryotes, we identified a number of bacterial cupin proteins of unknown function that share low similarity with mammalian CDO and that conserve many residues in the active-site pocket of CDO. Putative bacterial CDOs predicted to have CDO activity were shown to have similar substrate specificity and kinetic parameters as eukaryotic CDOs. Information gleaned from crystal structures of mammalian CDO along with sequence information for homologs shown to have CDO activity facilitated the identification of a CDO family fingerprint motif. One key feature of the CDO fingerprint motif is that the canonical metal-binding glutamate residue in cupin motif 1 is replaced by a cysteine (in mammalian CDOs) or by a glycine (bacterial CDOs). The recent report that some putative bacterial CDO homologs are actually 3-mercaptopropionate dioxygenases suggests that the CDO family may include proteins with specificities for other thiol substrates. A paralog of CDO in mammals was also identified and shown to be the other mammalian thiol dioxygenase, cysteamine dioxygenase (ADO). A tentative fingerprint motif for ADOs, or DUF1637 family members, is proposed. In ADOs, the conserved glutamate residue in cupin motif 1 is replaced by either glycine or valine. Both ADOs and CDOs appear to represent unique clades within the cupin superfamily. PMID:20195658
Stipanuk, Martha H; Simmons, Chad R; Karplus, P Andrew; Dominy, John E
Adsorption of metals onto bacteria and soil takes place as stormwater runoff infiltrates into the subsurface. Changes in both bacterial surfaces and soil elemental content have been observed, and may alter the attachment of bacteria to soil surfaces. In this study, scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) analyses were performed on soil samples equilibrated with synthetic stormwater amended with copper, lead and zinc. The results demonstrate the presence of copper and zinc on soil surfaces. To investigate bacterial attachment behavior, sets of batch sorption experiments were conducted on Escherichia Coli (E. coli) under different chemical conditions by varying solution compositions (nutrient solution vs synthetic stormwater). The adsorption data is best described using theoretical linear isotherms. The equilibrium coefficient (Kd) of E. coli is higher in synthetic stormwater than in nutrient solution without heavy metals. The adsorption of heavy metals onto bacterial surfaces significantly decreases their negative surface charge as determined via zeta potential measurements (-17.0±5.96mv for E. coli equilibrated with synthetic stormwater vs -21.6±5.45mv for E. coli equilibrated with nutrient solution), indicating that bacterial attachment may increase due to the attachment of metals onto bacterial surfaces and their subsequent change in surface charge. The attachment efficiency (?) of bacteria was also calculated and compared for both solution chemistries. Bacterial attachment efficiency (?) in synthetic stormwater is 0.997, which is twice as high as that in nutrient solution(? 0.465). The ratio of bacterial diameter : collector diameter suggests minimal soil straining during bacterial transport. Results suggest that the presence of metals in synthetic stormwater leads to an increase in bacterial attachment to soil surfaces. In terms of designing stormwater infiltration basins, the presence of heavy metals seems to reduce the soil depth required to achieve certain levels of bacterial removal. This study demonstrates the effect of chemical constituents in stormwater runoff on bacterial transport in the subsurface.
Zhang, H.; Olson, M. S.
Multilocus sequence analysis (MLSA) protocols have been developed for species circumscription for many taxa. However, at present, no studies based on MLSA have been performed within any moderately halophilic bacterial group. To test the usefulness of MLSA with these kinds of micro-organisms, the family Halomonadaceae, which includes mainly halophilic bacteria, was chosen as a model. This family comprises ten genera with validly published names and 85 species of environmental, biotechnological and clinical interest. In some cases, the phylogenetic relationships between members of this family, based on 16S rRNA gene sequence comparisons, are not clear and a deep phylogenetic analysis using several housekeeping genes seemed appropriate. Here, MLSA was applied using the 16S rRNA, 23S rRNA, atpA, gyrB, rpoD and secA genes for species of the family Halomonadaceae. Phylogenetic trees based on the individual and concatenated gene sequences revealed that the family Halomonadaceae formed a monophyletic group of micro-organisms within the order Oceanospirillales. With the exception of the genera Halomonas and Modicisalibacter, all other genera within this family were phylogenetically coherent. Five of the six studied genes (16S rRNA, 23S rRNA, gyrB, rpoD and secA) showed a consistent evolutionary history. However, the results obtained with the atpA gene were different; thus, this gene may not be considered useful as an individual gene phylogenetic marker within this family. The phylogenetic methods produced variable results, with those generated from the maximum-likelihood and neighbour-joining algorithms being more similar than those obtained by maximum-parsimony methods. Horizontal gene transfer (HGT) plays an important evolutionary role in the family Halomonadaceae; however, the impact of recombination events in the phylogenetic analysis was minimized by concatenating the six loci, which agreed with the current taxonomic scheme for this family. Finally, the findings of this study also indicated that the 16S rRNA, gyrB and rpoD genes were the most suitable genes for future taxonomic studies using MLSA within the family Halomonadaceae. PMID:21478390
de la Haba, Rafael R; Márquez, M Carmen; Papke, R Thane; Ventosa, Antonio
This evaluation report of the Family to Family Program assesses parental attitudes towards their Family to Family experience and the functioning of their emotionally impaired children. Topics include administration and administrative support; recruitment of consumer families; identification of host families; consumer support services; and consumer…
Ramey, Luellen; Meyer, David P.
The human colon plays host to a diverse and metabolically complex community of microorganisms. While the colonic microbiome has been suggested to contribute to the development of colorectal cancer (CRC), a definitive link has not been made. The role in which the colon microflora could contribute to the initiation and/or progression of CRC is explored in this review. Potential mechanisms of bacterial oncogenesis are presented, along with lines of evidence derived from animal models of microbially induced CRC. Particular focus is given to the oncogenic capabilities of enterotoxigenic Bacteroides fragilis. Recent progress in defining the microbiome of CRC in the human population is evaluated, and the future challenges of linking specific etiologic agents to CRC are emphasized. PMID:23534358
Dejea, Christine; Wick, Elizabeth; Sears, Cynthia L
Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. Rather than direct binding, it is probable that these protein classes create an ice surface prior to ice crystal surface adsorption. Function is differentiated by molecular size of the protein. This paper reviews the similar and different aspects of bacterial antifreeze and ice nucleation proteins, the role of these proteins in freezing tolerance, prevalence of these proteins in psychrophiles, and current mechanisms of protein-ice interactions. PMID:24579057
Lorv, Janet S H; Rose, David R; Glick, Bernard R
The human colon plays host to a diverse and metabolically complex community of microorganisms. While the colonic microbiome has been suggested to contribute to the development of colorectal cancer (CRC), a definitive link has not been made. The role in which the colon microflora could contribute to the initiation and/or progression of CRC is explored in this review. Potential mechanisms of bacterial oncogenesis are presented, along with lines of evidence derived from animal models of microbially induced CRC. Particular focus is given to the oncogenic capabilities of enterotoxigenic Bacteroides fragilis. Recent progress in defining the microbiome of CRC in the human population is evaluated, and the future challenges of linking specific etiologic agents to CRC are emphasized.
Dejea, Christine; Wick, Elizabeth; Sears, Cynthia L
Regrowth of coliform bacteria in distribution systems has been a problem for a number of water utilities. Efforts to solve the regrowth problem have not been totally successful. The current project, which was conducted at the New Jersey American Water Co.-Swimming River Treatment Plant, showed that the occurrence of coliform bacteria in the distribution system could be associated with rainfall, water temperatures greater than 15 degrees C, total organic carbon levels greater than 2.4 mg/liter, and assimilable organic carbon levels greater than 50 micrograms of acetate carbon equivalents per liter. A multiple linear regression model based on free chlorine residuals present in dead-end sections of the distribution system and temperature predicted 83.8% of the heterotrophic plate count bacterial variation. To limit the growth of coliform bacteria in drinking water, the study concludes that assimilable organic carbon levels should be reduced to less than 50 micrograms/liter.
LeChevallier, M W; Schulz, W; Lee, R G
Membrane vesicle (MV) release remains undefined, despite its conservation among replicating Gram-negative bacteria both in vitro and in vivo. Proteins identified in Salmonella MVs, derived from the envelope, control MV production via specific defined domains that promote outer membrane protein-peptidoglycan (OM-PG) and OM protein-inner membrane protein (OM-PG-IM) interactions within the envelope structure. Modulation of OM-PG and OM-PG-IM interactions along the cell body and at division septa, respectively, maintains membrane integrity while coordinating localized release of MVs with distinct size distribution and protein content. These data support a model of MV biogenesis, wherein bacterial growth and division invoke temporary, localized reductions in the density of OM-PG and OM-PG-IM associations within the envelope structure, thus releasing outer membrane as MVs.
Deatherage, Brooke L.; Lara, J. Cano; Bergsbaken, Tessa; Barrett, Sara L. Rassoulian; Lara, Stephanie; Cookson, Brad T.
Diverse structural, functional and valuable polysaccharides are synthesized by bacteria of all taxa and secreted into the external environment. These polysaccharides are referred to as exopolysaccharides and they may either be homopolymeric or heteropolymeric in composition and of diverse high molecular weights (10 to 1000 kDa). The material properties of exopolysaccharides have revolutionized the industrial and medical sectors due to their retinue of functional applications and prospects. These applications have been extensive in areas such as pharmacological, nutraceutical, functional food, cosmeceutical, herbicides and insecticides among others, while prospects includes uses as anticoagulant, antithrombotic, immunomodulation, anticancer and as bioflocculants. Due to the extensive applications of bacterial exopolysaccharides, this overview provides basic information on their physiologic and morphologic functions as well as their applications and prospects in the medical and industrial sectors.
Nwodo, Uchechukwu U.; Green, Ezekiel; Okoh, Anthony I.
Many heterotrophic bacteria are known to release extracellular vesicles, facilitating interactions between cells and their environment from a distance. Vesicle production has not been described in photoautotrophs, however, and the prevalence and characteristics of vesicles in natural ecosystems is unknown. Here, we report that cultures of Prochlorococcus, a numerically dominant marine cyanobacterium, continuously release lipid vesicles containing proteins, DNA, and RNA. We also show that vesicles carrying DNA from diverse bacteria are abundant in coastal and open-ocean seawater samples. Prochlorococcus vesicles can support the growth of heterotrophic bacterial cultures, which implicates these structures in marine carbon flux. The ability of vesicles to deliver diverse compounds in discrete packages adds another layer of complexity to the flow of information, energy, and biomolecules in marine microbial communities. PMID:24408433
Biller, Steven J; Schubotz, Florence; Roggensack, Sara E; Thompson, Anne W; Summons, Roger E; Chisholm, Sallie W
Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. Rather than direct binding, it is probable that these protein classes create an ice surface prior to ice crystal surface adsorption. Function is differentiated by molecular size of the protein. This paper reviews the similar and different aspects of bacterial antifreeze and ice nucleation proteins, the role of these proteins in freezing tolerance, prevalence of these proteins in psychrophiles, and current mechanisms of protein-ice interactions.
Lorv, Janet S. H.; Rose, David R.; Glick, Bernard R.
Self-sustained turbulent structures have been observed in a wide range of living fluids, yet no quantitative theory exists to explain their properties. We report experiments on active turbulence in highly concentrated 3D suspensions of Bacillus subtilis and compare them with a minimal fourth-order vector-field theory for incompressible bacterial dynamics. Velocimetry of bacteria and surrounding fluid, determined by imaging cells and tracking colloidal tracers, yields consistent results for velocity statistics and correlations over 2 orders of magnitude in kinetic energy, revealing a decrease of fluid memory with increasing swimming activity and linear scaling between kinetic energy and enstrophy. The best-fit model allows for quantitative agreement with experimental data.
Dunkel, Jörn; Heidenreich, Sebastian; Drescher, Knut; Wensink, Henricus H.; Bär, Markus; Goldstein, Raymond E.
Various bacterial species accumulate intracellular polyhydroxyalkanoates (PHAs) granules as energy and carbon reserves inside their cells. PHAs are biodegradable, environmentally friendly and biocompatible thermoplastics. Varying in toughness and flexibility, depending on their formulation, they can be used in various ways similar to many nonbiodegradable petrochemical plastics currently in use. They can be used either in pure form or as additives to oil-derived plastics such as polyethylene. However, these bioplastics are currently far more expensive than petrochemically based plastics and are therefore used mostly in applications that conventional plastics cannot perform, such as medical applications. PHAs are immunologically inert and are only slowly degraded in human tissue, which means they can be used as devices inside the body. Recent research has focused on the use of alternative substrates, novel extraction methods, genetically enhanced species and mixed cultures with a view to make PHAs more commercially attractive. PMID:17578408
Verlinden, R A J; Hill, D J; Kenward, M A; Williams, C D; Radecka, I
The stress situations, including medical intervention (e.g. operations, antitumor drugs, irradiation, etc.) decrease the nonspecific resistance of the body. In these situations patients people have greater chance to get an opportunistic infection than healthy ones. The restoration or elevation of the activity of immune system in injured patients is a very important task of medicine. Minute amounts of bacterial endotoxin (LPS)--given parenterally--can elevate the nonspecific resistance. Unfortunately this beneficial influence is associated with noxious properties. Irradiation (60 Co-gamma; 150 kGy) is a good technique for the detoxification of LPS. The radiodetoxified endotoxin (RD-LPS) preparation (so-called TOLERIN) is less toxic but its beneficial properties is preserved. On the basis of animal experiments and clinical trials TOLERIN could be a suitable preparation for regeneration of the lymphoreticular-immune system and elevation of nonspecific resistance. PMID:9554170
A variety of associated lesions may require the neurosurgeon's assistance in the management of bacterial meningitis. As treatment of this infection of the central nervous system proceeds, the surgeon will have to decide about the concurrent or subsequent operative treatment of congenital dysraphic states, paraneural infections, compound fractures or penetrating wounds of thecranium or spine, or infected bypass shunts for cerebrospinal fluid (CSF). In patients with intractable meningitic infections the surgeon may have to insert a ventricular drainage-irrigation system to permit adequate perfusion of the CSF pathways with antibiotic. Hydrocephalus or subdural effusions complicating meningitis may bring the patient to the surgeon long after the infection has been cured. This paper examines these problems and outlines the current principles of management. Images FIG. 1 FIG. 2
Humphreys, R. P.
Bacterial survival was determined in linens (i) inoculated with Staphylococcus auerus (ii), taken from hospital isolation patients' beds, and (iii) used by students in their homes. Two different washers using temperatures of 38, 49, 54 and 60 C, respectively, for different times were empolyed along with a commercial tumbler dryer. Findings, after macerating the linens in Waring blender and enumerating on nonselective media, indicate that acceptable levels of survivors can be acheived in motel and hotel linens by an 8- to 10-min wash cycle at 54 C followed by adequate drying. However, it is recommended that a wash cycle with 60 C for 10 to 13 min be employed for linens in health care factilities. The microbial significance of various laundering practices is discussed. PMID:1090256
Walter, W G; Schillinger, J E
The preparation and characterization of new nanocomposite films based on two acrylic emulsions, composed of random copolymers of butyl acrylate and methyl methacrylate, and bacterial cellulose is reported. The new composite materials were obtained through a simple and green approach by casting water-based suspensions of the acrylic emulsions and bacterial cellulose nanofibrils. The excellent compatibility between these matrices and the
Eliane Trovatti; Lúcia Oliveira; Carmen S. R. Freire; Armando J. D. Silvestre; Carlos Pascoal Neto; José J. C. Cruz Pinto; Alessandro Gandini
Recent genetic and molecular analyses have revealed how several strategies enable bacteria to persist and overcome insect immune defences. Genetic and genomic tools that can be used with Drosophila melanogaster have enabled the characterization of the pathways that are used by insects to detect bacterial invaders and combat infection. Conservation of bacterial virulence factors and insect immune repertoires indicates that
Isabelle Vallet-Gely; Bruno Lemaitre; Frédéric Boccard
Bacterial coinfections occur in respiratory viral infections, but the attack rates and the clinical profile are not clear. The aim of this study was to determine bacterial coinfections in children hospitalized for acute expiratory wheezing with defined viral etiology. A total of 220 children aged 3 months to 16 years were investigated. The viral etiology of wheezing was confirmed by viral culture,
P. Lehtinen; T. Jartti; R. Virkki; T. Vuorinen; M. Leinonen; V. Peltola; A. Ruohola; O. Ruuskanen
Bacterial infections traditionally have not been considered major causes of cancer. Recently, however, bacteria have been linked to cancer by two mechanisms: induction of chronic inflammation and production of carcinogenic bacterial metabolites. The most specific example of the inflammatory mechanism of carcinogenesis is Helicobacter pylori infection. H. pylori has been epidemiologically linked to adenocarcinoma of the distal stomach by its propensity to cause lifelong inflammation. This inflammation is in turn thought to cause cancer by inducing cell proliferation and production of mutagenic free radicals and N-nitroso compounds. H. pylori is the first bacterium to be termed a definite cause of cancer in humans by the International Agency for Research on Cancer. Mutagenic bacterial metabolites are also suspected to increase risk for cancer. This model is best exemplified in colon cancer. Bile salt metabolites increase colonic cell proliferation. Exogenous compounds such as rutin may be metabolized into mutagens by resident colonic flora. Moreover, Bacteroides species can produce fecapentaenes, potent in vitro mutagens, in relatively high concentrations. In vivo data on human carcinogenesis by bacterial metabolites, however, are inconsistent. Local bacterial infections may also predispose to nonnodal lymphomas, although the mechanisms for this are unknown. Gastric lymphomas and immunoproliferative small intestinal disease have been most strongly linked to underlying bacterial infection. Because bacterial infections can be cured with antibiotics, identification of bacterial causes of malignancy could have important implications for cancer prevention.
The study presents evidence in support of the bacterial theory associated with the toxicity of Pyrodinium bahamense var. compressum. Bacterial endosymbionts from Philippine P. bahamense var. compressum strain Pbc MZRVA 042595 were isolated and identified via 16S rDNA sequence analysis. Taxonomic diversity of the identified culturable intracellular microbiota associated with Philippine P. bahamense var. compressum was established to be limited
Ma. Patricia V. Azanza; Rhodora V. Azanza; Vanessa Mercee D. Vargas; Cynthia T. Hedreyda
This overview has been supported by a review of the literature referring to the management of community-acquired pneumonia (in preparation). Difficulties diagnosing bacterial pneumonia include identifying the pathogens and the validation of radiographic signs suggesting bacterial or mycoplasmal infection. The World Health Organisation (WHO) has published guidelines for diagnosis which seem to be as relevant for developed as developing countries.
N. Coote; S. McKenzie
The bacterial ghost system is a novel vaccine delivery system unusual in that it combines excellent natural intrinsic adjuvant properties with versatile carrier functions for foreign antigens. The efficient tropism of bacterial ghosts (BG) for antigen presenting cells promotes the generation of both cellular and humoral responses to heterologous antigens and carrier envelope structures. The simplicity of both BG production
Ulrike Beate Mayr; Petra Walcher; Chakameh Azimpour; Eva Riedmann; Christoph Haller; Werner Lubitz
This article summarizes a bioaugmentation research project undertaken by a DOE-sponsored, multidisciplinary research team at a field site near Oyster, Virginia. The overall purpose of the ongoing project is to evaluate the relative importance of hydrogeological and geochemical heterogeneities in controlling bacterial transpor, and to develop an approach for quantitative prediction of bacterial transport needed to design optimal bioremediation strategies.
Balkwill, D (.); Chen, J (.); Deflaun, Mary (VISITORS); Dobbs, F (.); Dong, H (.); Fredrickson, Jim K. (BATTELLE (PACIFIC NW LAB)); Fuller, M (.); Green, M (BATTELLE (PACIFIC NW LAB)); Ginn, T (.); Griffin, T (.); Holben, W (.); Hubbard, S (.); Johnson, W (.); Long, Philip E. (BATTELLE (PACIFIC NW LAB)); Mailloux, B (.); Majer, E (.); Mcinerney, M (.); Murray, Christopher J. (BATTELLE (PACIFIC NW LAB)); Onstott, T (.); Phelps, T (.); Scheibe, Timothy D. (BATTELLE (PACIFIC NW LAB)); Swift, D (.); White, D (.); Wobber, F (.)
Marine particles in the ocean are exposed to diverse bacterial communities, and colonization and growth of attached bacteria are important processes in the degradation and transformation of the particles. In an earlier study, we showed that the initial colonization of model particles by individual bacterial strains isolated from marine aggregates was a function of attachment and detachment. In the present
Hans-Peter Grossart; T. Kiorboe; Kam Tang; Helle Ploug
This article investigates the relationships of child- and family-related variables with family function in families with children who have Duchenne muscular dystrophy. Child-related variables included level of disability (indicator: Barthel Index) and age at diagnosis. Family-related variables included caregiver health status (indicator: Duke Health Profile), family income and employment, family support (indicator: Family APGAR), family hardiness (indicator: Family Hardiness Index), and family functioning (indicator: Family Assessment Device). Family function displayed a significant correlation with age at diagnosis, but not with disability level. It was also significantly correlated with family hardiness, caregiver health status, and levels of family support, but not with income or employment variables. These findings highlight the need to assist families to cope with the presence of serious illness in their children. PMID:17873636
Chen, Jih-Yuan; Clark, Mary-Jo
The Bacterial Ghost (BG) platform technology is an innovative system for vaccine, drug or active substance delivery and for technical applications in white biotechnology. BGs are cell envelopes derived from Gram-negative bacteria. BGs are devoid of all cytoplasmic content but have a preserved cellular morphology including all cell surface structures. Using BGs as delivery vehicles for subunit or DNA-vaccines the particle structure and surface properties of BGs are targeting the carrier itself to primary antigen-presenting cells. Furthermore, BGs exhibit intrinsic adjuvant properties and trigger an enhanced humoral and cellular immune response to the target antigen. Multiple antigens of the native BG envelope and recombinant protein or DNA antigens can be combined in a single type of BG. Antigens can be presented on the inner or outer membrane of the BG as well as in the periplasm that is sealed during BG formation. Drugs or supplements can also be loaded to the internal lumen or periplasmic space of the carrier. BGs are produced by batch fermentation with subsequent product recovery and purification via tangential flow filtration. For safety reasons all residual bacterial DNA is inactivated during the BG production process by the use of staphylococcal nuclease A and/or the treatment with ?-propiolactone. After purification BGs can be stored long-term at ambient room temperature as lyophilized product. The production cycle from the inoculation of the pre-culture to the purified BG concentrate ready for lyophilization does not take longer than a day and thus meets modern criteria of rapid vaccine production rather than keeping large stocks of vaccines. The broad spectrum of possible applications in combination with the comparably low production costs make the BG platform technology a safe and sophisticated product for the targeted delivery of vaccines and active agents as well as carrier of immobilized enzymes for applications in white biotechnology.
Langemann, Timo; Koller, Verena Juliana; Muhammad, Abbas; Kudela, Pavol; Mayr, Ulrike Beate
Summary The culturability of several actinobacteria is con- trolled by resuscitation-promoting factors (Rpfs). These are proteins containing a c . 70-residue domain that adopts a lysozyme-like fold. The invariant cata- lytic glutamate residue found in lysozyme and various bacterial lytic transglycosylases is also conserved in the Rpf proteins. Rpf from Micrococcus luteus , the founder member of this protein family,
Galina V. Mukamolova; Alexey G. Murzin; Elena G. Salina; Galina R. Demina; Douglas B. Kell; Arseny S. Kaprelyants; Michael Young
The ubiquitous nature of bacteria enables them to survive in a wide variety of environments. Hence, the rise of various pathogenic species that are harmful to human health raises the need for the development of accurate sensing systems. Sensing systems are necessary for diagnosis and epidemiological control of pathogenic organism, especially in the food-borne pathogen and sanitary water treatment facility' bacterial populations. Bacterial sensing for the purpose of diagnosis can function in three ways: bacterial morphological visualization, specific detection of bacterial component and whole cell detection. This paper provides an overview of the currently available bacterial detection systems that ranges from microscopic observation to state-of-the-art smartphone-based detection. PMID:24836016
Gopinath, Subash C B; Tang, Thean-Hock; Chen, Yeng; Citartan, Marimuthu; Lakshmipriya, Thangavel
The bacterial biota of a methanol-fed denitrification reactor used to treat seawater at the Montreal Biodome were investigated using culture-dependent and molecular biology methods. The microbiota extracted from the reactor carriers were cultivated on three media. Three isolate types were recovered and their 16S ribosomal DNA (rDNA) genes were determined. The analysis showed that the isolate types were related to alpha-Proteobacteria. They are members of the Hyphomicrobium and Paracoccus genera and the Phyllobacteriaceae family. Uncultured bacteria were identified through a 16S rDNA library generated from total DNA extracted from the microbiota. Clones were screened for different restriction profiles and for different DGGE (denaturing gradient gel electrophoresis) migration profiles. More than 70% of clones have the same restriction profile, and the sequence of representative clones showed a relation with the Methylophaga members of the Piscirickettsia family (gamma-Proteobacteria). Sequences from other profiles were related to bacterial species involved in denitrification. The number of species in the denitrification reactor was estimated at 15. Bacterial colonization on newly added carriers in the denitrification reactor was monitored by PCR-DGGE. The DGGE migration profiles evolved during the first 5 weeks and then remained essentially unchanged. PCR-DGGE was also used to monitor the microbial profiles in various aquarium locations. As expected, bacterial populations differed from one location to another, except for the sand and trickling filters which presented similar DGGE migration profiles. PMID:12739074
Labbé, N; Juteau, P; Parent, S; Villemur, R
Pathogenic bacteria interact not only with the host organism but most probably also with the resident microbial flora. In the knot disease of the olive tree (Olea europaea), the causative agent is the bacterium Pseudomonas savastanoi pv. savastanoi (Psv). Two bacterial species, namely Pantoea agglomerans and Erwinia toletana, which are not pathogenic and are olive plant epiphytes and endophytes, have been found very often to be associated with the olive knot. We identified the chemical signals that are produced by strains of the three species isolated from olive knot and found that they belong to the N-acyl-homoserine lactone family of QS signals. The luxI/R family genes responsible for the production and response to these signals in all three bacterial species have been identified and characterized. Genomic knockout mutagenesis and in planta experiments showed that virulence of Psv critically depends on QS; however, the lack of signal production can be complemented by wild-type E. toletana or P. agglomerans. It is also apparent that the disease caused by Psv is aggravated by the presence of the two other bacterial species. In this paper we discuss the potential role of QS in establishing a stable consortia leading to a poly-bacterial disease. PMID:21677694
Hosni, Taha; Moretti, Chiaraluce; Devescovi, Giulia; Suarez-Moreno, Zulma Rocio; Fatmi, M' Barek; Guarnaccia, Corrado; Pongor, Sandor; Onofri, Andrea; Buonaurio, Roberto; Venturi, Vittorio
Pathogenic bacteria interact not only with the host organism but most probably also with the resident microbial flora. In the knot disease of the olive tree (Olea europaea), the causative agent is the bacterium Pseudomonas savastanoi pv. savastanoi (Psv). Two bacterial species, namely Pantoea agglomerans and Erwinia toletana, which are not pathogenic and are olive plant epiphytes and endophytes, have been found very often to be associated with the olive knot. We identified the chemical signals that are produced by strains of the three species isolated from olive knot and found that they belong to the N-acyl-homoserine lactone family of QS signals. The luxI/R family genes responsible for the production and response to these signals in all three bacterial species have been identified and characterized. Genomic knockout mutagenesis and in planta experiments showed that virulence of Psv critically depends on QS; however, the lack of signal production can be complemented by wild-type E. toletana or P. agglomerans. It is also apparent that the disease caused by Psv is aggravated by the presence of the two other bacterial species. In this paper we discuss the potential role of QS in establishing a stable consortia leading to a poly-bacterial disease.
Hosni, Taha; Moretti, Chiaraluce; Devescovi, Giulia; Suarez-Moreno, Zulma Rocio; Fatmi, M' Barek; Guarnaccia, Corrado; Pongor, Sandor; Onofri, Andrea; Buonaurio, Roberto; Venturi, Vittorio
Green Ulvacean marine macroalgae are distributed worldwide in coastal tidal and subtidal ecosystems. As for many living surfaces in the marine environment, little is known concerning the epiphytic bacterial biofilm communities that inhabit algal surfaces. This study reports on the largest published libraries of near full-length 16S rRNA genes from a marine algal surface (5293 sequences from six samples) allowing for an in-depth assessment of the diversity and phylogenetic profile of the bacterial community on a green Ulvacean alga. Large 16S rRNA gene libraries of surrounding seawater were also used to determine the uniqueness of this bacterial community. The surface of Ulva australis is dominated by sequences of Alphaproteobacteria and the Bacteroidetes, especially within the Rhodobacteriaceae, Sphingomonadaceae, Flavobacteriaceae and Sapropiraceae families. Seawater libraries were also dominated by Alphaproteobacteria and Bacteroidetes sequences, but were shown to be clearly distinct from U. australis libraries through the clustering of sequences into operational taxonomic units and Bray–Curtis similarity analysis. Almost no similarity was observed between these two environments at the species level, and only minor similarity was observed at levels of sequence clustering representing clades of bacteria within family and genus taxonomic groups. Variability between libraries of U. australis was relatively high, and a consistent sub-population of bacterial species was not detected. The competitive lottery model, originally derived to explain diversity in coral reef fishes, may explain the pattern of colonization of this algal surface.
Burke, Catherine; Thomas, Torsten; Lewis, Matt; Steinberg, Peter; Kjelleberg, Staffan
In this bilingual (English/Spanish) activity, learners create family trees by tracing the hands of their family members. Learners list inherited traits like eye color, freckles, and chin shape on the fingers of the left hands and list learned traits like favorite foods, games, and pets on the fingers of the right hands. Learners assemble the hands to form trees. Use this family activity to help learners distinguish between inherited and learned traits.
Utah, University O.
Students use the text The Relatives Came by Cynthia Rylant as a springboard for discussion about family traditions. After identifying the traditions observed by the relatives, students meet in small groups to brainstorm new traditions that could arise from the families gathering together during the winter. The lesson is concluded by having each student write about their own favorite family tradition and share it with a small group.
...2009-04-01 false Breathing circuit bacterial filter. 868.5260 Section 868... Â§ 868.5260 Breathing circuit bacterial filter. (a) Identification. A breathing circuit bacterial filter is a device that is...
...2010-04-01 false Breathing circuit bacterial filter. 868.5260 Section 868... Â§ 868.5260 Breathing circuit bacterial filter. (a) Identification. A breathing circuit bacterial filter is a device that is...
A method for the deposition of metals in bacterial cellulose and for the employment of the metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The method for impregnating bacterial cellulose with a m...
B. R. Evans H. M. O'Neill J. Woodward V. M. Jansen
Following an episode of typical transient global amnesia (TGA), a female patient reported similar clinical attacks in 2 maternal aunts. Prior reports of familial TGA are few, and no previous account of affected relatives more distant than siblings or parents was discovered in a literature survey. The aetiology of familial TGA is unknown. A pathophysiological mechanism akin to that in migraine attacks, comorbidity reported in a number of the examples of familial TGA, is one possibility. The study of familial TGA cases might facilitate the understanding of TGA aetiology.
Davies, R. Rhys; Larner, A.J.
The changes of taxa within the particle-attached bacterial assemblage during the decomposition of Microcystis blooms were investigated under darkness and anoxic condition in mesocosm experiments. During 14days of darkness incubation, chlorophyll-a (Ch-a) concentration decreased from 2000?g/L to 5?g/L. Samples were collected on days 0, 2 and 14 for bacterial 16S rRNA analysis, based on rapid decreases in the Chl-a concentration of water column. The total bacterial community DNA was extracted and 16S rRNA genes were amplified by polymerase chain reaction, cloned and sequenced of selected samples. The results showed that the abundance of attached bacteria increased significantly, and the composition of the particle-attached bacterial communities varied temporally during the decomposition of Microcystis blooms. The bacterial assemblage appeared to be dominated by members of Bacteroidetes, Alphaproteobacteria and Betaproteobacteria. Shift of some genera of Alphaproteobacteria and Alphaproteobacteria was also observed. Additionally, we found that the family Sphingomonas, affiliated with Alphaproteobacteria, identified as a microcystin-degrading bacterium, dominated the particle-attached bacterial communities. The results from the present study, together with previously published data highlighted the need for more studies concerning the bacterial degradation process in order to trace the environmental fate of microcystins in field conditions. PMID:24836132
Shao, Keqiang; Zhang, Lei; Wang, Yongping; Yao, Xin; Tang, Xiangming; Qin, Boqiang; Gao, Guang
A large number of collagen-like proteins have been identified in bacteria during the past 10years, principally from analysis of genome databases. These bacterial collagens share the distinctive Gly-Xaa-Yaa repeating amino acid sequence of animal collagens which underlies their unique triple-helical structure. A number of the bacterial collagens have been expressed in Escherichia coli, and they all adopt a triple-helix conformation. Unlike animal collagens, these bacterial proteins do not contain the post-translationally modified amino acid, hydroxyproline, which is known to stabilize the triple-helix structure and may promote self-assembly. Despite the absence of collagen hydroxylation, the triple-helix structures of the bacterial collagens studied exhibit a high thermal stability of 35-39°C, close to that seen for mammalian collagens. These bacterial collagens are readily produced in large quantities by recombinant methods, either in the original amino acid sequence or in genetically manipulated sequences. This new family of recombinant, easy to modify collagens could provide a novel system for investigating structural and functional motifs in animal collagens and could also form the basis of new biomedical materials with designed structural properties and functions. PMID:24434612
Yu, Zhuoxin; An, Bo; Ramshaw, John A M; Brodsky, Barbara
Many studies have shown that species sorting, that is, the selection by local environmental conditions is important for the composition and assembly of bacterial communities. On the other hand, there are other studies that could show that bacterial communities are neutrally assembled. In this study, we implemented a microcosm experiment with the aim to determine, at the same time, the importance of species sorting and neutral processes for bacterial community assembly during the colonisation of new, that is, sterile, habitats, by atmospheric bacteria. For this we used outdoor microcosms, which contained sterile medium from three different rock pools representing different environmental conditions, which were seeded by rainwater bacteria. We found some evidence for neutral assembly processes, as almost every 4th taxon growing in the microcosms was also detectable in the rainwater sample irrespective of the medium. Most of these taxa belonged to widespread families with opportunistic growth strategies, such as the Pseudomonadaceae and Comamonadaceae, indicating that neutrally assembled taxa may primarily be generalists. On the other hand, we also found evidence for species sorting, as one out of three media selected a differently composed bacterial community. Species sorting effects were relatively weak and established themselves via differences in relative abundance of generalists among the different media, as well as media-specific occurrences of a few specific taxa. In summary, our results suggest that neutral and species sorting processes interact during the assembly of bacterial communities and that their importance may differ depending on how many generalists and specialists are present in a community.
Langenheder, Silke; Szekely, Anna J
The number of species of Bacteria and Archaea (ca 5000) is surprisingly small considering their early evolution, genetic diversity and residence in all ecosystems. The bacterial species definition accounts in part for the small number of named species. The primary procedures required to identify new species of Bacteria and Archaea are DNA–DNA hybridization and phenotypic characterization. Recently, 16S rRNA gene sequencing and phylogenetic analysis have been applied to bacterial taxonomy. Although 16S phylogeny is arguably excellent for classification of Bacteria and Archaea from the Domain level down to the family or genus, it lacks resolution below that level. Newer approaches, including multilocus sequence analysis, and genome sequence and microarray analyses, promise to provide necessary information to better understand bacterial speciation. Indeed, recent data using these approaches, while meagre, support the view that speciation processes may occur at the subspecies level within ecological niches (ecovars) and owing to biogeography (geovars). A major dilemma for bacterial taxonomists is how to incorporate this new information into the present hierarchical system for classification of Bacteria and Archaea without causing undesirable confusion and contention. This author proposes the genomic–phylogenetic species concept (GPSC) for the taxonomy of prokaryotes. The aim is twofold. First, the GPSC would provide a conceptual and testable framework for bacterial taxonomy. Second, the GPSC would replace the burdensome requirement for DNA hybridization presently needed to describe new species. Furthermore, the GPSC is consistent with the present treatment at higher taxonomic levels.
Staley, James T
This paper explores the relationship between family governance practices and financial performance of the business and family\\u000a assets of business-owning families. A business-owning family that shares a focus on preserving and growing wealth as a family\\u000a is defined as the enterprising family. Results of the study are consistent with predictions about the functioning of the enterprising family derived from research
Marta M. Berent-BraunLorraine; Lorraine M. Uhlaner
We have experimentally and computationally defined a set of genes that form a conserved metabolic module in the ?-proteobacterium Caulobacter crescentus and used this module to illustrate a schema for the propagation of pathway-level annotation across bacterial genera. Applying comprehensive forward and reverse genetic methods and genome-wide transcriptional analysis, we (1) confirmed the presence of genes involved in catabolism of the abundant environmental sugar myo-inositol, (2) defined an operon encoding an ABC-family myo-inositol transmembrane transporter, and (3) identified a novel myo-inositol regulator protein and cis-acting regulatory motif that control expression of genes in this metabolic module. Despite being encoded from non-contiguous loci on the C. crescentus chromosome, these myo-inositol catabolic enzymes and transporter proteins form a tightly linked functional group in a computationally inferred network of protein associations. Primary sequence comparison was not sufficient to confidently extend annotation of all components of this novel metabolic module to related bacterial genera. Consequently, we implemented the Graemlin multiple-network alignment algorithm to generate cross-species predictions of genes involved in myo-inositol transport and catabolism in other ?-proteobacteria. Although the chromosomal organization of genes in this functional module varied between species, the upstream regions of genes in this aligned network were enriched for the same palindromic cis-regulatory motif identified experimentally in C. crescentus. Transposon disruption of the operon encoding the computationally predicted ABC myo-inositol transporter of Sinorhizobium meliloti abolished growth on myo-inositol as the sole carbon source, confirming our cross-genera functional prediction. Thus, we have defined regulatory, transport, and catabolic genes and a cis-acting regulatory sequence that form a conserved module required for myo-inositol metabolism in select ?-proteobacteria. Moreover, this study describes a forward validation of gene-network alignment, and illustrates a strategy for reliably transferring pathway-level annotation across bacterial species.
Boutte, Cara C.; Srinivasan, Balaji S.; Flannick, Jason A.; Novak, Antal F.; Martens, Andrew T.; Batzoglou, Serafim; Viollier, Patrick H.; Crosson, Sean
Monoacylglycerol lipases (MGLs) play an important role in lipid catabolism across all kingdoms of life by catalyzing the release of free fatty acids from monoacylglycerols. The three-dimensional structures of human and a bacterial MGL were determined only recently as the first members of this lipase family. In addition to the ?/?-hydrolase core, they showed unexpected structural similarities even in the cap region. Nevertheless, the structural basis for substrate binding and conformational changes of MGLs is poorly understood. Here, we present a comprehensive study of five crystal structures of MGL from Bacillus sp. H257 in its free form and in complex with different substrate analogs and the natural substrate 1-lauroylglycerol. The occurrence of different conformations reveals a high degree of conformational plasticity of the cap region. We identify a specific residue, Ile-145, that might act as a gatekeeper restricting access to the binding site. Site-directed mutagenesis of Ile-145 leads to significantly reduced hydrolase activity. Bacterial MGLs in complex with 1-lauroylglycerol, myristoyl, palmitoyl, and stearoyl substrate analogs enable identification of the binding sites for the alkyl chain and the glycerol moiety of the natural ligand. They also provide snapshots of the hydrolytic reaction of a bacterial MGL at different stages. The alkyl chains are buried in a hydrophobic tunnel in an extended conformation. Binding of the glycerol moiety is mediated via Glu-156 and water molecules. Analysis of the structural features responsible for cap plasticity and the binding modes of the ligands suggests conservation of these features also in human MGL.
Rengachari, Srinivasan; Aschauer, Philipp; Schittmayer, Matthias; Mayer, Nicole; Gruber, Karl; Breinbauer, Rolf; Birner-Gruenberger, Ruth; Dreveny, Ingrid; Oberer, Monika
Current detection and identification of micro-organisms is based on either rather unspecific rapid microscopy or on more accurate but complex and time-consuming procedures. In a medical context, the determination of the bacteria Gram type is of significant interest. The diagnostic of microbial infection often requires the identification of the microbiological agent responsible for the infection, or at least the identification of its family (Gram type), in a matter of minutes. In this work, we propose to use terahertz frequency range antennas for the enhanced selective detection of bacteria types. Several microorganisms are investigated by terahertz time-domain spectroscopy: a fast, contactless and damage-free investigation method to gain information on the presence and the nature of the microorganisms. We demonstrate that plasmonic antennas enhance the detection sensitivity for bacterial layers and allow the selective recognition of the Gram type of the bacteria.
Berrier, Audrey; Schaafsma, Martijn C.; Nonglaton, Guillaume; Bergquist, Jonas; Rivas, Jaime Gomez
Summary Glycosyltransferases (GTs) are a large family of enzymes that specifically transfer sugar moieties to a diverse range of substrates. The process of bacterial glycosylation (such as biosynthesis of glycolipids, glycoproteins, and polysaccharides) has been studied extensively, yet the majority of GTs involved remains poorly characterized. Besides predicting enzymatic parameters of GTs, the resolution of three-dimensional structures of GTs can help to determine activity, donor sugar binding, and acceptor substrate binding sites. It also facilitates amino acid sequence-based structural modeling and biochemical characterization of their homologues. Here we describe a general procedure to accomplish expression and purification of soluble and active recombinant GTs. Enzymatic characterization, and crystallization of GTs, and data refinement for structural analysis are also covered in this protocol.
Zhu, Fan; Wu, Ren; Zhang, Hua; Wu, Hui
The enzymatic transfer of ribose and deoxyribose residues in pyrimidine nucleosides to purines was catalyzed by cell-free extracts of various bacteria. Almost all the strains belonging to Enterobacteriaceae were capable of catalyzing the transfer reactions. The transfer activities were also detected among some bacterial strains of other families: Pseudomonadaceae, Corynebacteriaceae, Micrococcaceae, Bacteriaceae, and Bacillaceae. The rates of the transfer reactions were greatly enhanced in the presence of phosphate ion, and the participation of nucleoside phosphorylases in the reactions was suggested. Uridine phosphorylase, thymidine phosphorylase, and purine nucleoside phosphorylase were purified from cell-free extract of Aerobacter aerogenes IFO 3321. The ribosyl transfer from uridine to hypoxanthine was found to be catalyzed by the coupled reactions of uridine and purine nucleoside phosphorylases and the deoxyribosyl transfer from thymidine to hypoxanthine by the coupled reactions of thymidine and purine nucleoside phosphorylases.
Imada, Akira; Igarasi, Seizi
Carbonic anhydrases (CAs, EC 184.108.40.206) are metalloenzymes which catalyze the hydration of carbon dioxide to bicarbonate and protons. Many pathogenic bacteria encode such enzymes belonging to the ?-, ?-, and/or ?-CA families. In the last decade, the ?-CAs from Neisseria spp. and Helicobacter pylori as well as the ?-class enzymes from Escherichia coli, H. pylori, Mycobacterium tuberculosis, Brucella spp., Streptococcus pneumoniae, Salmonella enterica, and Haemophilus influenzae have been cloned and characterized in detail. For some of these enzymes the X-ray crystal structures were determined, and in vitro and in vivo inhibition studies with various classes of inhibitors, such as anions, sulfonamides and sulfamates reported. Although efficient inhibitors have been reported for many such enzymes, only for Neisseria spp., H. pylori, B. suis, and S. pneumoniae enzymes it has been possible to evidence inhibition of bacterial growth in vivo. Thus, bacterial CAs represent promising targets for obtaining antibacterials devoid of the resistance problems of the clinically used such agents but further studies are needed to validate these and other less investigated enzymes as novel drug targets.
Supuran, Claudiu T.
The push for the English-only literacy approach sends the wrong message to language-minority families. The Arlington (Virginia) Public Schools have established first-language pilot programs to accelerate Latino students' academic achievement and have welcomed community-based educational initiatives. A family-literacy program motivates parents to…
Osterling, Jorge P.; Violand-Sanchez, Emma; von Vacano, Marcela
The "Goldfinch" is a magazine that introduces children to different aspects of Iowa History. Each issue contains articles to provide in-depth knowledge of a topic about Iowa. The focus of this issue is homes and family life in Iowa history. Selections address what has been important to Iowa's families over time and what homes were like before…
Frese, Millie K., Ed.
Tests the utility of four standardized instruments used in assessing 105 families that sought services in a juvenile corrections setting for their teenage children. Results demonstrate that parents and adolescents can complete standardized assessment instruments and that the information provided can help in understanding distressed families. (RJM)
Combs-Orme, Terri; Thomas, Katherine H.
Editor's Note: The fact that Japan has the longest life expectancy in the world does not suggest that they need to revamp their whole sys¬ tem and develop a new system of educating family physicians. How¬ ever, maybe the family physicians can make the statistics even better. I find the volume ofvisits fascinating. When I visited Korea in 1993, there
Blake W. H. Smith; Ray Demers; Linda Garcia-Shelton
Amniotic bands can cause a wide variety of deformities and mutilations. They are generally considered sporadic. Two families are presented with apparent familial amniotic band anomalies. Additional cases in the literature are reviewed. These aggregations may be coincidental, and recurrence risk is apparently low. However, amniotic band malformations may be an indication for caution in the use of amniocentesis in future pregnancies. PMID:6829612
Lubinsky, M; Sujansky, E; Sanger, W; Salyards, P; Severn, C
This student research project explores the properties of a family of matrices of zeros and ones that arises from the study of the diagonal lengths in a regular polygon. There is one family for each n greater than 2. A series of exercises guides the student to discover the eigenvalues and eigenvectors of the matrices, which leads in turn to…
Fontaine, Anne; Hurley, Susan
When ontogeny takes place in a family, and parents provide essential resources for development, the parents become an environmental component to the development of a wide range of offspring traits. Because differences among parents may partly reflect genetic variation, this environmental component contains genes and may itself evolve. Also, when offspring play an active role in family interactions, offspring become
Familial molar pregnancies and gestational trophoblastic disease are exceedingly rare. In this case report, a family including four sisters and their cousin had molar pregnancies. Eldest sister had repeated molar pregnancies. Second sister had early abortion at her first pregnancy and partial molar pregnancy following blighted ovum by intrauterine insemination at her second pregnancy. Third sister had two molar pregnancies
This issue of the "Journal of the Wisconsin Communication Association" focuses on family communication and contains the following articles: "Marital Typologies: An Alternative Approach to the Study of Communication in Enduring Relations" by Mary Anne Fitzpatrick, "Intimate Communication and the Family" by Marilyn D. LaCourt, and "A Study in…
Barnes, Richard E., Ed.
Given the historical emergence of the AIDS epidemic first among gay men in the developed world, HIV interventions have primarily focused on individuals rather than families. Typically not part of traditional family structures, HIV-positive gay men in Europe and the US lived primarily in societies providing essential infrastructure for survival needs that highly value individual justice and freedom. Interventions were
M. J. Rotheram-Borus; D. Flannery; E. Rice; P. Lester
The 12 articles in this issue focus on the theme of family history resources: (1) "Introduction: Family History Resources" (Joseph F. Shubert); (2) "Work, Credentials, and Expectations of a Professional Genealogist" (Coreen P. Hallenbeck and Lewis W. Hallenbeck); (3) "Computers and Genealogy" (Theresa C. Strasser); (4) "Finding Historical Records…
Describes the New York Aquarium's program specifically designed for family learning and teaching. The program's goal is to create an environment where child-parent roles are dropped and where the philosophy that no one of us is as smart as all of us prevails. Strategies for family involvement are outlined. (MH)
Hensel, Karen A.
The goal of this article is to draw attention to the challenging problems associated with supporting evolving product families. After a general problem description, we focus on a single detail of supporting evolving product families. We propose and evaluate using industrial experts a method to measure the similarity between products.
Piërre van de Laar
This book is the report of the Family Ties Commission, which was established by the Association of Teacher Educators to study the relationship between home and school. Following the preface and two introductory essays, "Education and My Family" (K.B. O'Rourke as told to E. Johnson) and "Preparing for Successful Children" (B. Clawson), the book is…
Kaplan, Leonard, Ed.
A detailed review of current research and state-of-the-art ideas concerning both communication processes and family functioning is presented in this collection of articles. The volume is organized around three sections. Part 1, "The Development of Family Communication Patterns," contains: (1) "Communication in Infancy" (Marguerite Stevenson…
Fitzpatrick, Mary Anne, Ed.; Vangelisti, Anita L., Ed.
In the late 1980s, the Denver Art Museum initiated efforts to make the museum a destination for families. From 1997 to 2001, with a generous grant from The Pew Charitable Trusts, these efforts came to fruition. From the moment they walk through the doors, families' needs are anticipated. For example, they can pick up a welcoming brochure, Free…
Williams, Patterson; Garcia, Maria
American families and workplaces have both changed dramatically over the past half-century. Paid work by women has increased sharply, as has family instability. Education-related inequality in work hours and income has grown. These changes, says Suzanne Bianchi, pose differing work-life issues for parents at different points along the income…
Bianchi, Suzanne M.
Examined the relationship between communication and delinquency by comparing adolescents' self-reported delinquent behavior with their perceptions of family communication. Results indicate that communication is related to the commission of delinquent behavior. Differences arising from age, sex, and family marital status were also noted. (RJM)
Clark, Richard D.; Shields, Glenn
The author's family pollutes directly or indirectly in five major ways: wastewater discharge; automobile exhaust; home heating oil furnace exhaust; trash disposal; and electricity usage (and the use of other consumer goods whose manufacture and transport caused some level of pollution). He decided to try to quantify how much his family contributed to pollution in one year, 1988. Four sources
The Family Constellation Scale (FC Scale) is an instrument that assesses perceived birth order in families. It can be used in counseling to help initiate conversations about various traits and assumptions that tend to characterize first-born, middle-born children, youngest-born, and only children. It provides both counselors and clients insights…
Bacterial pathogens that are multi-drug resistant compromise the effectiveness of treatment when they are the causative agents of infectious disease. These multi-drug resistance mechanisms allow bacteria to survive in the presence of clinically useful antimicrobial agents, thus reducing the efficacy of chemotherapy towards infectious disease. Importantly, active multi-drug efflux is a major mechanism for bacterial pathogen drug resistance. Therefore, because of their overwhelming presence in bacterial pathogens, these active multi-drug efflux mechanisms remain a major area of intense study, so that ultimately measures may be discovered to inhibit these active multi-drug efflux pumps.
Kumar, Sanath; Varela, Manuel F.
Singlet oxygen is one of several reactive oxygen species that can destroy biomolecules, microorganisms and other cells. Traditionally, the response to singlet oxygen has been termed photo-oxidative stress, as light-dependent processes in photosynthetic cells are major biological sources of singlet oxygen. Recent work identifying a core set of singlet oxygen stress response genes across various bacterial species highlights the importance of this response for survival by both photosynthetic and non-photosynthetic cells. Here, we review how bacterial cells mount a transcriptional response to photo-oxidative stress in the context of what is known about bacterial stress responses to other reactive oxygen species.
Ziegelhoffer, Eva C.; Donohue, Timothy J.
Terpenoid compounds are generally considered to be plant or fungal metabolites, although a small number of odorous terpenoid metabolites of bacterial origin have been known for many years. Recently, extensive bacterial genome sequencing and bioinformatic analysis of deduced bacterial proteins using a profile hidden Markov model have revealed more than a hundred distinct predicted terpene synthase genes. Although some of these synthase genes might be silent in the parent microorganisms under normal laboratory culture conditions, the controlled overexpression of these genes in a versatile heterologous host has made it possible to identify the biochemical function of cryptic genes and isolate new terpenoid metabolites. PMID:22999173
Yamada, Yuuki; Cane, David E; Ikeda, Haruo