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1

Transformation of gram positive bacteria by sonoporation  

SciTech Connect

The present invention provides a sonoporation-based method that can be universally applied for delivery of compounds into Gram positive bacteria. Gram positive bacteria which can be transformed by sonoporation include, for example, Bacillus, Streptococcus, Acetobacterium, and Clostridium. Compounds which can be delivered into Gram positive bacteria via sonoporation include nucleic acids (DNA or RNA), proteins, lipids, carbohydrates, viruses, small organic and inorganic molecules, and nano-particles.

Yang, Yunfeng; Li, Yongchao

2014-03-11

2

Antimicrobial Resistance in Gram-Positive Bacteria  

Microsoft Academic Search

Gram-positive bacteria are common causes of bloodstream and other infections in hospitalized patients in the United States, and the percentage of nosocomial bloodstream infections caused by antibiotic-resistant gram-positive bacteria is increasing. Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) are of particular concern. In the United States, approximately 60% of staphylococcal infections in the intensive care unit are now caused

Louis B. Rice

2006-01-01

3

Bacteriocins of gram-positive bacteria.  

PubMed Central

In recent years, a group of antibacterial proteins produced by gram-positive bacteria have attracted great interest in their potential use as food preservatives and as antibacterial agents to combat certain infections due to gram-positive pathogenic bacteria. They are ribosomally synthesized peptides of 30 to less than 60 amino acids, with a narrow to wide antibacterial spectrum against gram-positive bacteria; the antibacterial property is heat stable, and a producer strain displays a degree of specific self-protection against its own antibacterial peptide. In many respects, these proteins are quite different from the colicins and other bacteriocins produced by gram-negative bacteria, yet customarily they also are grouped as bacteriocins. Although a large number of these bacteriocins (or bacteriocin-like inhibitory substances) have been reported, only a few have been studied in detail for their mode of action, amino acid sequence, genetic characteristics, and biosynthesis mechanisms. Nevertheless, in general, they appear to be translated as inactive prepeptides containing an N-terminal leader sequence and a C-terminal propeptide component. During posttranslational modifications, the leader peptide is removed. In addition, depending on the particular type, some amino acids in the propeptide components may undergo either dehydration and thioether ring formation to produce lanthionine and beta-methyl lanthionine (as in lantibiotics) or thio ester ring formation to form cystine (as in thiolbiotics). Some of these steps, as well as the translocation of the molecules through the cytoplasmic membrane and producer self-protection against the homologous bacteriocin, are mediated through specific proteins (enzymes). Limited genetic studies have shown that the structural gene for such a bacteriocin and the genes encoding proteins associated with immunity, translocation, and processing are present in a cluster in either a plasmid, the chromosome, or a transposon. Following posttranslational modification and depending on the pH, the molecules may either be released into the environment or remain bound to the cell wall. The antibacterial action against a sensitive cell of a gram-positive strain is produced principally by destabilization of membrane functions. Under certain conditions, gram-negative bacterial cells can also be sensitive to some of these molecules. By application of site-specific mutagenesis, bacteriocin variants which may differ in their antimicrobial spectrum and physicochemical characteristics can be produced. Research activity in this field has grown remarkably but sometimes with an undisciplined regard for conformity in the definition, naming, and categorization of these molecules and their genetic effectors. Some suggestions for improved standardization of nomenclature are offered. PMID:7603408

Jack, R W; Tagg, J R; Ray, B

1995-01-01

4

Sortase enzymes in Gram-positive bacteria  

PubMed Central

Summary In Gram-positive bacteria proteins are displayed on the cell surface using sortase enzymes. These cysteine transpeptidases join proteins bearing an appropriate sorting signal to strategically positioned amino groups on the cell surface. Working alone, or in concert with other enzymes, sortases either attach proteins to the cross-bridge peptide of the cell wall or they link proteins together to form pili. Because surface proteins play a fundamental role in microbial physiology and are frequently virulence factors, sortase enzymes have been intensely studied since their discovery a little more than a decade ago. Based on their primary sequences and functions sortases can be partitioned into distinct families called class A to F enzymes. Most bacteria elaborate their surfaces using more than one type of sortase that function non-redundantly by recognizing unique sorting signals within their protein substrates. Here we review what is known about the functions of these enzymes and the molecular basis of catalysis. Particular emphasis is placed on ‘pilin’ specific class C sortases that construct structurally complex pili. Exciting new data have revealed that these enzymes are amazingly promiscuous in the substrates that they can employ and that there is a startling degree of diversity in their mechanism of action. We also review recent data that suggest that sortases are targeted to specific sites on the cell surface where they work with other sortases and accessory factors to properly function. PMID:22026821

Spirig, Thomas; Weiner, Ethan M.; Clubb, Robert T.

2013-01-01

5

Screening genomes of Gram-positive bacteria for  

E-print Network

Screening genomes of Gram-positive bacteria for double-glycine-motif- containing peptides Secreted-positive bacteria, the double-glycine (GG) motif plays a key role in many peptide secretion systems involved Microbiology Comment #12;peptides and class II bacteriocins, produced by streptococci and lactic acid bacteria

6

Methods for targetted mutagenesis in gram-positive bacteria  

SciTech Connect

The present invention provides a method of targeted mutagenesis in Gram-positive bacteria. In particular, the present invention provides a method that effectively integrates a suicide integrative vector into a target gene in the chromosome of a Gram-positive bacterium, resulting in inactivation of the target gene.

Yang, Yunfeng

2014-05-27

7

Antimicrobial Resistance Among Epidemiologically Important Gram-Positive Bacteria  

Microsoft Academic Search

\\u000a The emergence of antimicrobial resistance among clinically relevant bacteria has resulted in profound changes in the approach\\u000a to treatment of infections caused by these pathogens. This chapter will focus on three epidemiologically important gram-positive\\u000a bacteria: Streptococcus pneumoniae, Staphylococcus aureus, and Enterococcus species. Common infections due to these organisms, common resistance mechanisms, and available treatment options will be\\u000a reviewed.

Cassandra D. Salgado

8

Antimicrobial Peptide Resistance Mechanisms of Gram-Positive Bacteria  

PubMed Central

Antimicrobial peptides, or AMPs, play a significant role in many environments as a tool to remove competing organisms. In response, many bacteria have evolved mechanisms to resist these peptides and prevent AMP-mediated killing. The development of AMP resistance mechanisms is driven by direct competition between bacterial species, as well as host and pathogen interactions. Akin to the number of different AMPs found in nature, resistance mechanisms that have evolved are just as varied and may confer broad-range resistance or specific resistance to AMPs. Specific mechanisms of AMP resistance prevent AMP-mediated killing against a single type of AMP, while broad resistance mechanisms often lead to a global change in the bacterial cell surface and protect the bacterium from a large group of AMPs that have similar characteristics. AMP resistance mechanisms can be found in many species of bacteria and can provide a competitive edge against other bacterial species or a host immune response. Gram-positive bacteria are one of the largest AMP producing groups, but characterization of Gram-positive AMP resistance mechanisms lags behind that of Gram-negative species. In this review we present a summary of the AMP resistance mechanisms that have been identified and characterized in Gram-positive bacteria. Understanding the mechanisms of AMP resistance in Gram-positive species can provide guidelines in developing and applying AMPs as therapeutics, and offer insight into the role of resistance in bacterial pathogenesis. PMID:25419466

McBride, Shonna M.

2014-01-01

9

Conjugative type IV secretion systems in Gram-positive bacteria  

PubMed Central

Bacterial conjugation presents the most important means to spread antibiotic resistance and virulence factors among closely and distantly related bacteria. Conjugative plasmids are the mobile genetic elements mainly responsible for this task. All the genetic information required for the horizontal transmission is encoded on the conjugative plasmids themselves. Two distinct concepts for horizontal plasmid transfer in Gram-positive bacteria exist, the most prominent one transports single stranded plasmid DNA via a multi-protein complex, termed type IV secretion system, across the Gram-positive cell envelope. Type IV secretion systems have been found in virtually all unicellular Gram-positive bacteria, whereas multicellular Streptomycetes seem to have developed a specialized system more closely related to the machinery involved in bacterial cell division and sporulation, which transports double stranded DNA from donor to recipient cells. This review intends to summarize the state of the art of prototype systems belonging to the two distinct concepts; it focuses on protein key players identified so far and gives future directions for research in this emerging field of promiscuous interbacterial transport. PMID:24129002

Goessweiner-Mohr, Nikolaus; Arends, Karsten; Keller, Walter; Grohmann, Elisabeth

2013-01-01

10

Fibrinogen-binding proteins of Gram-positive bacteria.  

PubMed

Fibrinogen (Fg), the major clotting protein in blood plasma, plays key roles in blood coagulation and thrombosis. In addition, this 340 kD glycoprotein is a stress inducible protein; its synthesis is dramatically upregulated during inflammation or under exposure to stress such systemic infections. This regulation of Fg expression indicates that Fg also participates in the host defense system against infections. In fact, a number of reported studies have demonstrated the involvement of both the intrinsic and extrinsic pathways of coagulation; the thrombotic and the fibrinolytic systems in the pathophysiology of infectious diseases. It is, therefore, perhaps not surprising that many pathogenic bacteria can interact with Fg and manipulate its biology. This review focuses on the major Fg-binding proteins (Fgbps) from Gram-positive bacteria with an emphasis on those that are known to have an effect on coagulation and thrombosis. PMID:17849038

Rivera, Jose; Vannakambadi, Ganesh; Höök, Magnus; Speziale, Pietro

2007-09-01

11

Type IV Pili in Gram-Positive Bacteria  

PubMed Central

SUMMARY Type IV pili (T4P) are surface-exposed fibers that mediate many functions in bacteria, including locomotion, adherence to host cells, DNA uptake (competence), and protein secretion and that can act as nanowires carrying electric current. T4P are composed of a polymerized protein, pilin, and their assembly apparatuses share protein homologs with type II secretion systems in eubacteria and the flagella of archaea. T4P are found throughout Gram-negative bacterial families and have been studied most extensively in certain model Gram-negative species. Recently, it was discovered that T4P systems are also widespread among Gram-positive species, in particular the clostridia. Since Gram-positive and Gram-negative bacteria have many differences in cell wall architecture and other features, it is remarkable how similar the T4P core proteins are between these organisms, yet there are many key and interesting differences to be found as well. In this review, we compare the two T4P systems and identify and discuss the features they have in common and where they differ to provide a very broad-based view of T4P systems across all eubacterial species. PMID:24006467

Craig, Lisa

2013-01-01

12

Quorum sensing by peptide pheromones and two component signal transduction systems in Gram-positive bacteria  

Microsoft Academic Search

Cell-density-dependent gene expression appears to be widely spread in bacteria. This quorum-sensing phenomenon has been well established in Gram-negative bacteria, where N-acyl homoserine lactones are the diffusible communication molecules that modulate cell-density-dependent phenotypes. Similarly, a variety of processes are known to be regulated in a cell-density- or growth-phase-dependent manner in Gram-positive bacteria. Examples of such quorum-sensing modes in Gram-positive bacteria

Michiel Kleerebezem; Luis E. N. Quadri; Oscar P. Kuipers; Willem M. de Vos

1997-01-01

13

Phylogenetic diversity of Gram-positive bacteria cultured from Antarctic deep-sea sponges  

Microsoft Academic Search

Gram-positive bacteria, specifically actinobacteria and members of the order Bacillales, are well-known producers of important\\u000a secondary metabolites. Little is known about the diversity of Gram-positive bacteria associated with Antarctic deep-sea sponges.\\u000a In this study, cultivation-based approaches were applied to investigate the Gram-positive bacteria associated with the Antarctic\\u000a sponges Rossella nuda, Rossella racovitzae (Porifera: Hexactinellida), and Myxilla mollis, Homaxinella balfourensis, Radiella

Yanjuan Xin; Manmadhan Kanagasabhapathy; Dorte Janussen; Song Xue; Wei Zhang

14

Polyhydroxyalkanoates in Gram-positive bacteria: insights from the genera Bacillus and Streptomyces  

Microsoft Academic Search

Gram-positive bacteria, notably Bacillus and Streptomyces, have been used extensively in industry. However, these microorganisms have not yet been exploited for the production of the biodegradable polymers, polyhydroxyalkanoates (PHAs). Although PHAs have many potential applications, the cost of production means that medical applications are currently the main area of use. Gram-negative bacteria, currently the only commercial source of PHAs, have

Sabeel P. Valappil; Aldo R. Boccaccini; Christopher Bucke; Ipsita Roy

2007-01-01

15

Pili in Gram-positive bacteria: assembly, involvement in colonization and biofilm development  

PubMed Central

Various cell-surface multisubunit protein polymers, known as pili or fimbriae, have a pivotal role in the colonization of specific host tissues by many pathogenic bacteria. In contrast to Gram-negative bacteria, Gram-positive bacteria assemble pili by a distinct mechanism involving a transpeptidase called sortase. Sortase crosslinks individual pilin monomers and ultimately joins the resulting covalent polymer to the cell-wall peptidoglycan. Here we review current knowledge of this mechanism and the roles of Gram-positive pili in the colonization of specific host tissues, modulation of host immune responses and the development of bacterial biofilms. PMID:18083568

Mandlik, Anjali; Swierczynski, Arlene; Das, Asis; Ton-That, Hung

2010-01-01

16

Acquired inducible antimicrobial resistance in Gram-positive bacteria  

PubMed Central

A major contributor to the emergence of antibiotic resistance in Gram-positive bacterial pathogens is the expansion of acquired, inducible genetic elements. Although acquired, inducible antibiotic resistance is not new, the interest in its molecular basis has been accelerated by the widening distribution and often ‘silent’ spread of the elements responsible, the diagnostic challenges of such resistance and the mounting limitations of available agents to treat Gram-positive infections. Acquired, inducible antibiotic resistance elements belong to the accessory genome of a species and are horizontally acquired by transformation/recombination or through the transfer of mobile DNA elements. The two key, but mechanistically very different, induction mechanisms are: ribosome-sensed induction, characteristic of the macrolide–lincosamide–streptogramin B antibiotics and tetracycline resistance, leading to ribosomal modifications or efflux pump activation; and resistance by cell surface-associated sensing of ?-lactams (e.g., oxacillin), glycopeptides (e.g., vancomycin) and the polypeptide bacitracin, leading to drug inactivation or resistance due to cell wall alterations. PMID:22913355

Chancey, Scott T; Zähner, Dorothea; Stephens, David S

2012-01-01

17

The type I macrophage scavenger receptor binds to gram-positive bacteria and recognizes lipoteichoic acid.  

PubMed Central

Macrophage scavenger receptors exhibit unusually broad binding specificity for polyanionic ligands and have been implicated in atherosclerosis and various host defense functions. Using a radiolabeled, secreted form of the type I bovine macrophage scavenger receptor in an in vitro binding assay, we have found that this receptor binds to intact Gram-positive bacteria, including Streptococcus pyogenes, Streptococcus agalactiae, Staphylococcus aureus, Enterococcus hirae, and Listeria monocytogenes. Competition binding studies using purified lipoteichoic acid, an anionic polymer expressed on the surface of most Gram-positive bacteria, show that lipoteichoic acids are scavenger receptor ligands and probably mediate binding of the receptor to Gram-positive bacteria. Lipoteichoic acids, for which no host cell receptors have previously been identified, are implicated in the pathogenesis of septic shock due to Gram-positive bacteria. Scavenger receptors may participate in host defense by clearing lipoteichoic acid and/or intact bacteria from tissues and the circulation during Gram-positive sepsis. Since scavenger receptors have been previously shown to bind to and facilitate bloodstream clearance of Gram-negative bacterial endotoxin (lipopolysaccharide), these receptors may provide a general mechanism for macrophage recognition and internalization of pathogens and their cell surface components. Images PMID:8127896

Dunne, D W; Resnick, D; Greenberg, J; Krieger, M; Joiner, K A

1994-01-01

18

Rapid method for distinction of gram-negative from gram-positive bacteria  

Microsoft Academic Search

A rapid method for distinction between gram-negative and grampositive bacteria by means of a 3% solution of potassium hydroxide is tested on 71 gram-positive and 55 gram-negative bacterial strains. The method proved reliable with one exception only, a Bacillus macerans strain. That strain was definately gram-negative on staining. Other Bacillus strains were proved gram-positive by the test, even those being

T. Gregersen

1978-01-01

19

Vancomycin-resistant gram-positive bacteria isolated from human sources.  

PubMed Central

Recent reports of infections with vancomycin-resistant gram-positive bacteria prompted us to study vancomycin-resistant isolates from human sources to characterize the types of bacteria displaying this phenotype. Thirty-six vancomycin-resistant gram-positive isolates, 14 from clinical specimens and 22 from stool samples, were identified. These isolates were tentatively identified as Lactobacillus spp. (25 strains), Leuconostoc spp. (6 strains), and Pediococcus spp. (3 strains) on the basis of morphology and physiological tests. Two isolates of indeterminate morphology could not be unambiguously assigned to a genus. Four isolates of vancomycin-resistant lactobacilli from normally sterile body sites were considered to be clinically significant. Vancomycin-resistant gram-positive bacteria may represent an emerging class of nosocomial pathogens. Better methods for distinguishing the various genera in the clinical microbiology laboratory are needed. PMID:3182995

Ruoff, K L; Kuritzkes, D R; Wolfson, J S; Ferraro, M J

1988-01-01

20

Rose Bengal-decorated silica nanoparticles as photosensitizers for inactivation of gram-positive bacteria  

NASA Astrophysics Data System (ADS)

A new type of photosensitizer, made from Rose Bengal (RB)-decorated silica (SiO2-NH2-RB) nanoparticles, was developed to inactivate gram-positive bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA), with high efficiency through photodynamic action. The nanoparticles were characterized microscopically and spectroscopically to confirm their structures. The characterization of singlet oxygen generated by RB, both free and immobilized on a nanoparticle surface, was performed in the presence of anthracene-9,10-dipropionic acid. The capability of SiO2-NH2-RB nanoparticles to inactivate bacteria was tested in vitro on both gram-positive and gram-negative bacteria. The results showed that RB-decorated silica nanoparticles can inactivate MRSA and Staphylococcus epidermidis (both gram-positive) very effectively (up to eight-orders-of-magnitude reduction). Photosensitizers of such design should have good potential as antibacterial agents through a photodynamic mechanism.

Guo, Yanyan; Rogelj, Snezna; Zhang, Peng

2010-02-01

21

Ubiquitous detection of gram-positive bacteria with bioorthogonal magnetofluorescent nanoparticles.  

PubMed

The ability to rapidly diagnose gram-positive pathogenic bacteria would have far reaching biomedical and technological applications. Here we describe the bioorthogonal modification of small molecule antibiotics (vancomycin and daptomycin), which bind to the cell wall of gram-positive bacteria. The bound antibiotics conjugates can be reacted orthogonally with tetrazine-modified nanoparticles, via an almost instantaneous cycloaddition, which subsequently renders the bacteria detectable by optical or magnetic sensing. We show that this approach is specific, selective, fast and biocompatible. Furthermore, it can be adapted to the detection of intracellular pathogens. Importantly, this strategy enables detection of entire classes of bacteria, a feat that is difficult to achieve using current antibody approaches. Compared to covalent nanoparticle conjugates, our bioorthogonal method demonstrated 1-2 orders of magnitude greater sensitivity. This bioorthogonal labeling method could ultimately be applied to a variety of other small molecules with specificity for infectious pathogens, enabling their detection and diagnosis. PMID:21967150

Chung, Hyun Jung; Reiner, Thomas; Budin, Ghyslain; Min, Changwook; Liong, Monty; Issadore, David; Lee, Hakho; Weissleder, Ralph

2011-11-22

22

Chapter 7 Culture media for non-sporulating Gram-positive food spoilage bacteria  

Microsoft Academic Search

The spoilage association especially of protein-rich foods can be dominated by Gram-positive bacteria, notably lactic acid bacteria (LAB) which affect vacuum packaged refrigerated processed meats and some dairy products.New food ecosystems are being created by novel packaging and processing technologies, resulting in spoilage associations differing from those previously reported. In addition, improvement in identifica-tion methods, allow the detection and isolation

W. H. Holzapfel

1995-01-01

23

Drosophila Toll is activated by Gram-positive bacteria through a circulating peptidoglycan recognition protein  

Microsoft Academic Search

Microbial infection activates two distinct intracellular signalling cascades in the immune-responsive fat body of Drosophila. Gram-positive bacteria and fungi predominantly induce the Toll signalling pathway, whereas Gram-negative bacteria activate the Imd pathway. Loss-of-function mutants in either pathway reduce the resistance to corresponding infections. Genetic screens have identified a range of genes involved in these intracellular signalling cascades, but how they

Tatiana Michel; Jean-Marc Reichhart; Jules A. Hoffmann; Julien Royet

2001-01-01

24

In vitro conjugal transfer of tetracycline resistance from Lactobacillus isolates to other Gram-positive bacteria  

E-print Network

were able to transfer in vitro this resistance to Enterococcus faecalis at frequencies ranging from to transfer the tet(M) gene to other Gram-positive bacteria, including Enterococcus faecalis, Lactococcus strains were used: (i) E. faecalis JH2-2 [14] was grown in brain heart infusion 0378-1097 / 03 / $22.00 Ã?

Gent, Universiteit

25

BACTERIOCINS OF GRAM-POSITIVE BACTERIA AND THEIR APPLICATION IN BIOTECHNOLOGY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Many Gram-positive bacteria produce small peptides (bacteriocins) that have antimicrobial activity. Some bacteriocins have a broad spectrum, but many are highly selective and can only inhibit closely related species or strains. Bacteriocin specificity is not well understood, but specific receptors...

26

Novel Cassette-Based Shuttle Vector System for Gram-Positive Bacteria  

Microsoft Academic Search

Virulent bacterial strains have developed complex metabolic and regulatory pathways to enable them to thrive in the in vivo environment during infection. Understanding how the regula- tory networks operate requires manipulation of many genes and expressing them temporally and spatially at different levels or under separate regulatory controls. In the case of gram- positive bacteria including staphylococci, the introduction of

Emmanuelle Charpentier; Ana I. Anton; Peter Barry; Berenice Alfonso; Yuan Fang; Richard P. Novick

2004-01-01

27

Microarray-Based Detection of 90 Antibiotic Resistance Genes of Gram-Positive Bacteria  

Microsoft Academic Search

A disposable microarray was developed for detection of up to 90 antibiotic resistance genes in gram-positive bacteria by hybridization. Each antibiotic resistance gene is represented by two specific oligonucleotides chosen from consensus sequences of gene families, except for nine genes for which only one specific oligonucleotide could be developed. A total of 137 oligonucleotides (26 to 33 nucleotides in length

Vincent Perreten; Lorianne Vorlet-Fawer; Peter Slickers; Ralf Ehricht; Peter Kuhnert; Joachim Frey

2005-01-01

28

Construction and evaluation of multisite recombinatorial (Gateway) cloning vectors for Gram-positive bacteria  

PubMed Central

Background The Gateway recombinatorial cloning system allows easy and rapid joining of DNA fragments. Here we report the construction and evaluation of three different Gram-positive vectors that can be used with the Multisite Gateway cloning system to rapidly produce new gene arrangements in plasmid constructs for use in a variety of Gram-positive bacteria. Results Comparison of patterns of reporter gene expression with conventionally constructed clones show that the presence of residual recombination (att) sites does not have an effect on patterns of gene expression, although overall levels of gene expression may vary. Rapid construction of these new vectors allowed vector/gene combinations to be optimized following evaluation of plasmid constructs in different bacterial cells and demonstrates the benefits of plasmid construction using Gateway cloning. Conclusion The residual att sites present after Gateway cloning did not affect patterns of promoter induction in Gram-positive bacteria and there was no evidence of differences in mRNA stability of transcripts. However overall levels of gene expression may be reduced, possibly due to some post-transcriptional event. The new vectors described here allow faster, more efficient cloning in range of Gram-positive bacteria. PMID:17880697

Perehinec, Tania M; Qazi, Saara NA; Gaddipati, Sanyasi R; Salisbury, Vyvyan; Rees, Catherine ED; Hill, Philip J

2007-01-01

29

Multiple Responses of Gram-Positive and Gram-Negative Bacteria to Mixture of Hydrocarbons  

PubMed Central

Most of our knowledge about pollutants and the way they are biodegraded in the environment has previously been shaped by laboratory studies using hydrocarbon-degrading bacterial strains isolated from polluted sites. In present study Gram-positive (Mycobacterium sp. IBBPo1, Oerskovia sp. IBBPo2, Corynebacterium sp. IBBPo3) and Gram-negative (Chryseomonas sp. IBBPo7, Pseudomonas sp. IBBPo10, Burkholderia sp. IBBPo12) bacteria, isolated from oily sludge, were found to be able to tolerate pure and mixture of saturated hydrocarbons, as well as pure and mixture of monoaromatic and polyaromatic hydrocarbons. Isolated Gram-negative bacteria were more tolerant to mixture of saturated (n-hexane, n-hexadecane, cyclohexane), monoaromatic (benzene, toluene, ethylbenzene) and polyaromatic (naphthalene, 2-methylnaphthalene, fluorene) hydrocarbons than Gram-positive bacteria. There were observed cellular and molecular modifications induced by mixture of saturated, monoaromatic and polyaromatic hydrocarbons to Gram-positive and Gram-negative bacteria. These modifications differ from one strain to another and even for the same bacterial strain, according to the nature of hydrophobic substrate. PMID:24031541

Marilena L?z?roaie, Mihaela

2010-01-01

30

Lipoteichoic Acids, Phosphate-Containing Polymers in the Envelope of Gram-Positive Bacteria  

PubMed Central

Lipoteichoic acids (LTA) are polymers of alternating units of a polyhydroxy alkane, including glycerol and ribitol, and phosphoric acid, joined to form phosphodiester units that are found in the envelope of Gram-positive bacteria. Here we review four different types of LTA that can be distinguished on the basis of their chemical structure and describe recent advances in the biosynthesis pathway for type I LTA, d-alanylated polyglycerol-phosphate linked to di-glucosyl-diacylglycerol. The physiological functions of type I LTA are discussed in the context of inhibitors that block their synthesis and of mutants with discrete synthesis defects. Research on LTA structure and function represents a large frontier that has been investigated in only few Gram-positive bacteria. PMID:24415723

Schneewind, Olaf

2014-01-01

31

Synthetic Teichoic Acid Conjugate Vaccine against Nosocomial Gram-Positive Bacteria  

PubMed Central

Lipoteichoic acids (LTA) are amphiphilic polymers that are important constituents of the cell wall of many Gram-positive bacteria. The chemical structures of LTA vary among organisms, albeit in the majority of Gram-positive bacteria the LTAs feature a common poly-1,3-(glycerolphosphate) backbone. Previously, the specificity of opsonic antibodies for this backbone present in some Gram-positive bacteria has been demonstrated, suggesting that this minimal structure may be sufficient for vaccine development. In the present work, we studied a well-defined synthetic LTA-fragment, which is able to inhibit opsonic killing of polyclonal rabbit sera raised against native LTA from Enterococcus faecalis 12030. This promising compound was conjugated with BSA and used to raise rabbit polyclonal antibodies. Subsequently, the opsonic activity of this serum was tested in an opsonophagocytic assay and specificity was confirmed by an opsonophagocytic inhibition assay. The conjugated LTA-fragment was able to induce specific opsonic antibodies that mediate killing of the clinical strains E. faecalis 12030, Enterococcus faecium E1162, and community-acquired Staphylococcus aureus strain MW2 (USA400). Prophylactic immunization with the teichoic acid conjugate and with the rabbit serum raised against this compound was evaluated in active and passive immunization studies in mice, and in an enterococcal endocarditis rat model. In all animal models, a statistically significant reduction of colony counts was observed indicating that the novel synthetic LTA-fragment conjugate is a promising vaccine candidate for active or passive immunotherapy against E. faecalis and other Gram-positive bacteria. PMID:25333799

Laverde, Diana; Wobser, Dominique; Romero-Saavedra, Felipe; Hogendorf, Wouter; van der Marel, Gijsbert; Berthold, Martin; Kropec, Andrea; Codee, Jeroen; Huebner, Johannes

2014-01-01

32

Problems associated with the direct viable count procedure applied to gram-positive bacteria.  

PubMed

Despite the numerous advantages of fluorescent in situ hybridization (FISH) for identifying a single bacterial cell with 16S rRNA probes, problems are encountered with starving bacteria in natural samples. The original direct viable count procedure (DVC) includes a revivification step in the presence of an antibiotic inhibiting cell division. Cells elongate and accumulate ribosomes. This results in a natural amplification of 16S rRNA molecules (target of FISH). However, it is limited to gram-negative bacteria which are sensitive to nalidixic acid. The objective of this study was to develop a procedure for estimating the number of metabolically active gram-positive Staphylococcus aureus and Enterococcus faecalis cells by the use of a method which combines the number of substrate-responsive cells and their identification by FISH. It was observed that no single published DVC method could apply to taxonomically different gram-positive bacteria. Since cells were not counted, the revivification step in presence of nalidixic acid will be referred to as revivification without cell division. For each species, different low-nutrient media and complex media, different fluoroquinolones and beta-lactam antibiotics, concentrations of antibiotics, combinations of antibiotics, temperature and time were evaluated using bacteria in different physiological states and in natural samples. Enumeration of bacteria by plate counts and direct FISH were compared. The improved procedure should yield information about the physiological state, the taxonomic identity, and the enumeration of viable gram-positive bacteria. The application of DVC to an entire ecosystem is presently still a challenge. PMID:10791758

Regnault, B; Martin-Delautre, S; Grimont, P A

2000-04-10

33

Identification of gram-negative and gram-positive bacteria by fluorescence studies  

NASA Astrophysics Data System (ADS)

Several type strains of bacteria including Vibrio fischeri, Azotobacter vinelandii, Enterobacter cloacae, and Corynebacterium xerosis, were cultured in the laboratory following standard diagnostic protocol based on their individual metabolic strategies. The bacterial cultures were not further treated and they were studied in their pristine state (pure culture - axenic). The fluorescent studies were applied using a continuous wave and a pulsed excitation light sources. Emission and excitation spectra were recorded for the continuous wave excitation and they all show similar spectral features with the exception of the gram positive bacteria showing vibronic structures. The vibrational modes involved in these vibronic bands have energy typical for carbon-carbon vibrations. The fluorescence is quenched in addition of water, even a very thin layer, which confirms that the observed spectral features originate from the outer parts of the bacteria. These results allow to conclude that the fluorescence spectroscopy can be used as a method for studying the membranes of the bacteria and eventually to discriminate between gram positive and gram negative bacteria. The pulsed experiments show that the fluorescence lifetime is in the sub-microsecond range. The results indicate that the observed spectra are superposition of the emission with different lifetimes.

Demchak, Jonathan; Calabrese, Joseph; Tzolov, Marian

2011-03-01

34

Critical cell wall hole size for lysis in Gram-positive bacteria  

NASA Astrophysics Data System (ADS)

Gram-positive bacteria transport molecules necessary for their survival through holes in their cell wall. The holes in cell walls need to be large enough to let critical nutrients pass through. However, the cell wall must also function to prevent the bacteria's membrane from protruding through a large hole into the environment and lysing the cell. As such, we hypothesize that there exists a range of cell wall hole sizes that allow for molecule transport but prevent membrane protrusion. Here we develop and analyze a biophysical theory of the response of a Gram-positive cell's membrane to the formation of a hole in the cell wall. We predict a critical hole size in the range 15-24nm beyond which lysis occurs. To test our theory, we measured hole sizes in Streptococcus pyogenes cells undergoing enzymatic lysis via transmission electron microscopy. The measured hole sizes are in strong agreement with our theoretical prediction. Together, the theory and experiments provide a means to quantify the mechanisms of death of Gram-positive cells via enzymatically mediated lysis and provides insight into the range of cell wall hole sizes compatible with bacterial homeostasis.

Mitchell, Gabriel; Wiesenfeld, Kurt; Nelson, Daniel; Weitz, Joshua

2013-03-01

35

Comparative genomics of the methionine metabolism in Gram-positive bacteria: a variety of regulatory systems  

PubMed Central

Regulation of the methionine biosynthesis and transport genes in bacteria is rather diverse and involves two RNA-level regulatory systems and at least three DNA-level systems. In particular, the methionine metabolism in Gram-positive bacteria was known to be controlled by the S-box and T-box mechanisms, both acting on the level of premature termination of transcription. Using comparative analysis of genes, operons and regulatory elements, we described the methionine metabolic pathway and the methionine regulons in available genomes of Gram-positive bacteria. A large number of methionine-specific RNA elements were identified. S-boxes were shown to be widely distributed in Bacillales and Clostridia, whereas methionine-specific T-boxes occurred mostly in Lactobacillales. A candidate binding signal (MET-box) for a hypothetical methionine regulator, possibly MtaR, was identified in Streptococcaceae, the only family in the Bacillus/Clostridium group of Gram-positive bacteria having neither S-boxes, nor methionine-specific T-boxes. Positional analysis of methionine-specific regulatory sites complemented by genome context analysis lead to identification of new members of the methionine regulon, both enzymes and transporters, and reconstruction of the methionine metabolism in various bacterial genomes. In particular, we found candidate transporters for methionine (MetT) and methylthioribose (MtnABC), as well as new enzymes forming the S-adenosylmethionine recycling pathway. Methionine biosynthetic enzymes in various bacterial species are quite variable. In particular, Oceanobacillus iheyensis possibly uses a homolog of the betaine–homocysteine methyltransferase bhmT gene from vertebrates to substitute missing bacterial-type methionine synthases. PMID:15215334

Rodionov, Dmitry A.; Vitreschak, Alexey G.; Mironov, Andrey A.; Gelfand, Mikhail S.

2004-01-01

36

Sonodynamic Excitation of Rose Bengal for Eradication of Gram-Positive and Gram-Negative Bacteria  

PubMed Central

Photodynamic antimicrobial chemotherapy based on photosensitizers activated by illumination is limited by poor penetration of visible light through skin and tissues. In order to overcome this problem, Rose Bengal was excited in the dark by 28?kHz ultrasound and was applied for inactivation of bacteria. It is demonstrated, for the first time, that the sonodynamic technique is effective for eradication of Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The net sonodynamic effect was calculated as a 3-4 log10 reduction in bacteria concentration, depending on the cell and the Rose Bengal concentration and the treatment time. Sonodynamic treatment may become a novel and effective form of antimicrobial therapy and can be used for low-temperature sterilization of medical instruments and surgical accessories. PMID:23509759

Nakonechny, Faina; Nisnevitch, Michael; Nitzan, Yeshayahu; Nisnevitch, Marina

2013-01-01

37

Buffering Capacity and Membrane H+ Conductance of Neutrophilic and Alkalophilic Gram-Positive Bacteria  

PubMed Central

Buffering capacity and membrane H+ conductance were examined in three gram-positive bacteria, Staphylococcus aureus, Bacillus subtilis, and Bacillus alcalophilus. An acid pulse technique was used to measure both parameters. The buffering capacity and membrane H+ conductance of B. alcalophilus are influenced by the pH of the medium and the culture conditions. Suspensions of B. alcalophilus cells from both H. A. medium and l-malate medium cultures grown at pH 10.5 exhibited higher values for these parameters than cells grown at pH 8.5. B. alcalophilus grown aerobically had a lower buffering capacity and a lower membrane conductance for protons than the neutrophilic bacteria S. aureus and B. subtilis. Fermenting cells exhibited significantly higher values for both variables than respiring cells. PMID:9546171

Rius, Núria; Lorén, José G.

1998-01-01

38

Sonodynamic excitation of Rose Bengal for eradication of gram-positive and gram-negative bacteria.  

PubMed

Photodynamic antimicrobial chemotherapy based on photosensitizers activated by illumination is limited by poor penetration of visible light through skin and tissues. In order to overcome this problem, Rose Bengal was excited in the dark by 28?kHz ultrasound and was applied for inactivation of bacteria. It is demonstrated, for the first time, that the sonodynamic technique is effective for eradication of gram-positive Staphylococcus aureus and gram-negative Escherichia coli. The net sonodynamic effect was calculated as a 3-4 log10 reduction in bacteria concentration, depending on the cell and the Rose Bengal concentration and the treatment time. Sonodynamic treatment may become a novel and effective form of antimicrobial therapy and can be used for low-temperature sterilization of medical instruments and surgical accessories. PMID:23509759

Nakonechny, Faina; Nisnevitch, Michael; Nitzan, Yeshayahu; Nisnevitch, Marina

2013-01-01

39

Optimization of Fluorescent Tools for Cell Biology Studies in Gram-Positive Bacteria  

PubMed Central

The understanding of how Gram-positive bacteria divide and ensure the correct localization of different molecular machineries, such as those involved in the synthesis of the bacterial cell surface, is crucial to design strategies to fight bacterial infections. In order to determine the correct subcellular localization of fluorescent proteins in Streptococcus pneumoniae, we have previously described tools to express derivatives of four fluorescent proteins, mCherry, Citrine, CFP and GFP, to levels that allow visualization by fluorescence microscopy, by fusing the first ten amino acids of the S. pneumoniae protein Wze (the i-tag), upstream of the fluorescent protein. Here, we report that these tools can also be used in other Gram-positive bacteria, namely Lactococcus lactis, Staphylococcus aureus and Bacillus subtilis, possibly due to optimized translation rates. Additionally, we have optimized the i-tag by testing the effect of the first ten amino acids of other pneumococcal proteins in the increased expression of the fluorescent protein Citrine. We found that manipulating the structure and stability of the 5? end of the mRNA molecule, which may influence the accessibility of the ribosome, is determinant to ensure the expression of a strong fluorescent signal. PMID:25464377

Henriques, Mafalda X.; Gomes, João Paulo; Filipe, Sérgio R.

2014-01-01

40

[Mobilization transfer of the pUB110 plasmid between gram-positive bacteria].  

PubMed

The three factor crosses between the donor strain Bacillus subtilis 168 harbouring the plasmid pUB102-4, Bacillus thuringiensis strain carrying the mobilizing plasmid pAM beta 1 and recipient strain Lactobacillus fermenti were conducted in order to elaborate the optimal conditions of the plasmid pUB102-4 mobilization for transfer into gram-positive microorganisms and to elucidate the possible expression of endogluconase genes in a lactobacillus strain. The Lactobacillus fermenti transconjugants carrying the pUB102-4 plasmid were obtained in the three factor reciprocal crosses with the streptococcus recipient strain and Bacillus subtilis recipients. The presence of the plasmids in transconjugants was confirmed by colony hybridization with the [32P]-labelled plasmid DNA and KMC-ase activity in transconjugant cells. The proposed system of crosses using the high copy number plasmid derivatives of pUB110 mobilized with high frequency by the pAM beta 1 plasmid demonstrates the possibility to increase the circle of gram-positive host bacteria avoiding time and labour consuming operations. PMID:1745269

Kozlova, E V; Aminov, R I; Boronin, A M

1991-09-01

41

Biochemical characterization of Gram-positive and Gram-negative plant-associated bacteria with micro-Raman spectroscopy.  

PubMed

Raman spectra of Gram-positive and Gram-negative plant bacteria have been measured with micro-Raman spectrometers equipped with 785 and 514.5 nm lasers. The Gram-positive bacteria Microbacterium testaceum, Paenibacillus validus, and Clavibacter michiganensis subsp. michiganensis have strong carotenoid bands in the regions 1155-1157 cm(-1) and 1516-1522 cm(-1) that differentiate them from other tested Gram-negative bacteria. In the Raman spectrum of Gram-positive bacteria Bacillus megaterium excited with 785 nm laser, the Raman bands at 1157 and 1521 cm(-1) are weak in intensity compared to other Gram-positive bacteria, and these bands did not show significant resonance Raman enhancement in the spectrum recorded with 514.5 nm laser excitation. The Gram-positive bacteria could be separated from each other based on the bands associated with the in-phase C=C (v(1)) vibrations of the polyene chain of carotenoids. None of the Gram-negative bacteria tested had carotenoid bands. The bacteria in the genus Xanthomonas have a carotenoid-like pigment, xanthomonadin, identified in Xanthomonas axonopodis pv. dieffenbachiae, and it is a unique Raman marker for the bacteria. The representative bands for xanthomonadin were the C-C stretching (v(2)) vibrations of the polyene chain at 1135-1136 cm(-1) and the in-phase C=C (v(1)) vibrations of the polyene chain at 1529-1531 cm(-1), which were distinct from the carotenoid bands of other tested bacteria. The tyrosine peak in the region 1170-1175 cm(-1) was the only other marker present in Gram-negative bacteria that was absent in all tested Gram-positives. A strong-intensity exopolysaccharide-associated marker at 1551 cm(-1) is a distinguishable feature of Enterobacter cloacae. The Gram-negative Agrobacterium rhizogenes and Ralstonia solanacearum were differentiated from each other and other tested bacteria on the basis of presence or absence and relative intensities of peaks. The principal components analysis (PCA) of the spectra excited with 785 nm laser differentiated the various strains of bacteria based on the unique pigments these bacteria do or do not possess. Raman spectroscopy of diverse plant bacteria that are pathogenic and non-pathogenic to plants, and isolated from plants and soil, indicates the possibilities of using the method in understanding plant-bacterial interactions at the cellular level. PMID:20412629

Paret, Mathews L; Sharma, Shiv K; Green, Lisa M; Alvarez, Anne M

2010-04-01

42

[Retrospective analysis of the Gram-positive bacteria-infected cases in the Department of Hematology].  

PubMed

This study was purposed to evaluate the efficacy and safety of linezolid, vancomycin and teicoplanin for the treatment of patients infected by Gram-positive bacteria in the Department of Hematology by retrospective analysis. The patients with fever in our department from January to December in 2011 were selected for blood culture with Gram-positive bacteria and treated with linezolid, vancomycin or teicoplanin alone.Various parameters were recorded before and after treatment, such as fever time, respiratory symptoms, physical signs, radiographic changes, blood and biochemical routine, and adverse reactions. The efficacy and safety of linezolid, vancomycin and teicoplanin were compared according to the fever abating time, bacterial clearance rate, clinical efficiencies and adverse events. The patients were divided into linezolid group (15 patients), vancomycin group (17 patients) and teicoplanin group (20 patients). The results showed that the mean time of fever abating in linezolid group was (4.43 ± 3.15)d, bacterial clearance rate and clinical efficiency in linezolid group were 55.56% and 86.67%, respectively. The above three data in vancomycin group were (6.83 ± 4.67)d, 54.54% and 76.47% respectively, and were (5.57 ± 4.16)d, 41.67% and 80.00% in teicoplanin group respectively. There was no statistically significant difference between three groups (P > 0.05). There were one case of diarrhea and two cases of thrombocytopenia in the linezolid group, and one case of nausea and two cases of creatinine increase in the vancomycin group. There were three cases of thrombocytopenia in the teicoplanin group. The thrombocytopenia in five cases and the hemogram drop in patients with leukemia after treatment were overlapped, their drug treatment did not stop, but their thrombocytopoiesis recovered to normal-level, thus the drug treatment were considered as no relation with thrombocytopenia. It is concluded that the treatment efficacy between linezolid, vancomycin and teicoplanin for Gram-positive bacterial infections is not statistically different, but linezolid maybe have advantage over vancomycin and teicoplanin in fever abating time, bacterial clearance rate and clinical efficiency. PMID:24156452

Jing, Yu; Bo, Jian; Zhao, Yu; Li, Hong-Hua; Wang, Shu-Hong; Huang, Wen-Rong; Wang, Quan-Shun

2013-10-01

43

Sortases and the Art of Anchoring Proteins to the Envelopes of Gram-Positive Bacteria  

PubMed Central

The cell wall envelopes of gram-positive bacteria represent a surface organelle that not only functions as a cytoskeletal element but also promotes interactions between bacteria and their environment. Cell wall peptidoglycan is covalently and noncovalently decorated with teichoic acids, polysaccharides, and proteins. The sum of these molecular decorations provides bacterial envelopes with species- and strain-specific properties that are ultimately responsible for bacterial virulence, interactions with host immune systems, and the development of disease symptoms or successful outcomes of infections. Surface proteins typically carry two topogenic sequences, i.e., N-terminal signal peptides and C-terminal sorting signals. Sortases catalyze a transpeptidation reaction by first cleaving a surface protein substrate at the cell wall sorting signal. The resulting acyl enzyme intermediates between sortases and their substrates are then resolved by the nucleophilic attack of amino groups, typically provided by the cell wall cross bridges of peptidoglycan precursors. The surface protein linked to peptidoglycan is then incorporated into the envelope and displayed on the microbial surface. This review focuses on the mechanisms of surface protein anchoring to the cell wall envelope by sortases and the role that these enzymes play in bacterial physiology and pathogenesis. PMID:16524923

Marraffini, Luciano A.; DeDent, Andrea C.; Schneewind, Olaf

2006-01-01

44

?, a New Subunit of RNA Polymerase Found in Gram-Positive Bacteria  

PubMed Central

RNA polymerase in bacteria is a multisubunit protein complex that is essential for gene expression. We have identified a new subunit of RNA polymerase present in the high-A+T Firmicutes phylum of Gram-positive bacteria and have named it ?. Previously ? had been identified as a small protein (?1) that copurified with RNA polymerase. We have solved the structure of ? by X-ray crystallography and show that it is not an ? subunit. Rather, ? bears remarkable similarity to the Gp2 family of phage proteins involved in the inhibition of host cell transcription following infection. Deletion of ? shows no phenotype and has no effect on the transcriptional profile of the cell. Determination of the location of ? within the assembly of RNA polymerase core by single-particle analysis suggests that it binds toward the downstream side of the DNA binding cleft. Due to the structural similarity of ? with Gp2 and the fact they bind similar regions of RNA polymerase, we hypothesize that ? may serve a role in protection from phage infection. PMID:25092033

Keller, Andrew N.; Yang, Xiao; Wiedermannová, Jana; Delumeau, Olivier; Krásný, Libor

2014-01-01

45

Isolation of Highly Active Monoclonal Antibodies against Multiresistant Gram-Positive Bacteria.  

PubMed

Multiresistant nosocomial pathogens often cause life-threatening infections that are sometimes untreatable with currently available antibiotics. Staphylococci and enterococci are the predominant Gram-positive species associated with hospital-acquired infections. These infections often lead to extended hospital stay and excess mortality. In this study, a panel of fully human monoclonal antibodies was isolated from a healthy individual by selection of B-cells producing antibodies with high opsonic killing against E. faecalis 12030. Variable domains (VH and VL) of these immunoglobulin genes were amplified by PCR and cloned into an eukaryotic expression vector containing the constant domains of a human IgG1 molecule and the human lambda constant domain. These constructs were transfected into CHO cells and culture supernatants were collected and tested by opsonophagocytic assay against E. faecalis and S. aureus strains (including MRSA). At concentrations of 600 pg/ml, opsonic killing was between 40% and 70% against all strains tested. Monoclonal antibodies were also evaluated in a mouse sepsis model (using S. aureus LAC and E. faecium), a mouse peritonitis model (using S. aureus Newman and LAC) and a rat endocarditis model (using E. faecalis 12030) and were shown to provide protection in all models at a concentration of 4 ?g/kg per animal. Here we present a method to produce fully human IgG1 monoclonal antibodies that are opsonic in vitro and protective in vivo against several multiresistant Gram-positive bacteria. The monoclonal antibodies presented in this study are significantly more effective compared to another monoclonal antibody currently in clinical trials. PMID:25706415

Rossmann, Friederike S; Laverde, Diana; Kropec, Andrea; Romero-Saavedra, Felipe; Meyer-Buehn, Melanie; Huebner, Johannes

2015-01-01

46

Gram-Positive Bacteria Are Potent Inducers of Monocytic Interleukin-12 (IL-12) while Gram-Negative Bacteria Preferentially Stimulate IL-10 Production  

PubMed Central

Interleukin-10 (IL-10) and IL-12 are two cytokines secreted by monocytes/macrophages in response to bacterial products which have largely opposite effects on the immune system. IL-12 activates cytotoxicity and gamma interferon (IFN-?) secretion by T cells and NK cells, whereas IL-10 inhibits these functions. In the present study, the capacities of gram-positive and gram-negative bacteria to induce IL-10 and IL-12 were compared. Monocytes from blood donors were stimulated with UV-killed bacteria from each of seven gram-positive and seven gram-negative bacterial species representing both aerobic and anaerobic commensals and pathogens. Gram-positive bacteria induced much more IL-12 than did gram-negative bacteria (median, 3,500 versus 120 pg/ml at an optimal dose of 25 bacteria/cell; P < 0.001), whereas gram-negative bacteria preferentially stimulated secretion of IL-10 (650 versus 200 pg/ml; P < 0.001). Gram-positive species also induced stronger major histocompatibility complex class II-restricted IFN-? production in unfractionated blood mononuclear cells than did gram-negative species (12,000 versus 3,600 pg/ml; P < 0.001). The poor IL-12-inducing capacity of gram-negative bacteria was not remediated by addition of blocking anti-IL-10 antibodies to the cultures. No isolated bacterial component could be identified that mimicked the potent induction of IL-12 by whole gram-positive bacteria, whereas purified LPS induced IL-10. The results suggest that gram-positive bacteria induce a cytokine pattern that promotes Th1 effector functions. PMID:10816515

Hessle, Christina; Andersson, Bengt; Wold, Agnes E.

2000-01-01

47

In vitro activities of daptomycin (LY146032) and paldimycin (U-70,138F) against anaerobic gram-positive bacteria.  

PubMed

The in vitro activities of daptomycin (LY146032), paldimycin (U-70,138F), vancomycin, and penicillin G against 344 clinical isolates of anaerobic gram-positive bacteria were determined by an agar dilution method in calcium-supplemented (50 micrograms/ml) Wilkins-Chalgren medium, using an inoculum of 10(5) CFU. Daptomycin demonstrated excellent activity against a broad range of anaerobic gram-positive cocci and bacilli, including Peptostreptococcus, Eubacterium, Bifidobacterium, Actinomyces, Propionibacterium, and Lactobacillus species and Clostridium difficile. Highly resistant strains (MIC, greater than or equal to 64 micrograms/ml) were encountered sporadically from different genera, but these accounted for only 3% of all isolates tested. Vancomycin showed similar activity but was less active against Lactobacillus species and Peptostreptococcus prevotii. Paldimycin was inactive against most genera of anaerobic gram-positive bacteria. Overall, penicillin G remained the most broadly active agent against these isolates. PMID:2840019

Chow, A W; Cheng, N

1988-05-01

48

Testing of different antibiotics against Gram-positive and Gram-negative bacteria isolated from plant tissue culture  

Microsoft Academic Search

Different Gram-positive and Gram-negative bacteria (Staphylococcus xylosus, S. aureus, S. cohnii, Bacillus sp., Corynebacterium sp., Pseudomonas vesicularis) were isolated from homogenized shoot tips of Drosera rotundifolia, Spatiphyllum sp., Syngonium cv. White butterfly, Nephrolepis exaltata cv. Teddy Junior. Growth inhibition of selected bacterial strains was examined using 28 different single antibiotics and 7 antibiotic mixtures. It was found that with the

W. Kneifel; W. Leonhardt

1992-01-01

49

Dustborne and airborne gram-positive and gram-negative bacteria in high versus low ERMI homes  

EPA Science Inventory

The study aimed at investigating Gram-positive and Gram-negative bacteria in moldy and non-moldy homes, as defined by the home's Environmental Relative Moldiness Index (ERMI) value. The ERMI values were determined from floor dust samples in 2010 and 2011 and homes were classified...

50

Variation of RAPD-fingerprint patterns using different DNA-extraction methods with Gram-positive bacteria  

Microsoft Academic Search

The effect of the DNA-extraction method used on fingerprint patterns of RAPD was studied usingStaphylococcus epidermidis andStreptococcus faecalis. The three methods tested (Chelex, microwave and phenol\\/chloroform) led to significantly different RAPD patterns. The microwave technique generated reproducible patterns and seems the most suitable for RAPD analysis of Gram-positive bacteria.

Y. Abed; A. Davin; R. N. Charrel; C. Bollet; P. Micco

1995-01-01

51

Soluble bacterial constituents down-regulate secretion of IL-12 in response to intact Gram-positive bacteria.  

PubMed

Intact Gram-positive bacteria induce production of large amounts of IL-12 from freshly isolated human monocytes. Here the bacterial structures and signalling pathways involved were studied and compared with those leading to IL-6 production, and to IL-12 production in response to LPS after IFN-gamma pre-treatment. Intact bifidobacteria induced massive production of IL-12 (1 ng/ml) and IL-6 (>30 ng/ml) from human PBMC, whereas fragmented bifidobacteria induced IL-6, but no IL-12. IL-12 production induced by intact bifidobacteria was inhibited by pre-treatment with bifidobacterial sonicate, peptidoglycan, muramyl dipeptide, lipoteichoic acid, the soluble TLR2 agonist Pam(3)Cys-SK(4), or anti-TLR2 antibodies. Blocking of phagocytosis by cytochalasin, inhibition of the JNK or NF-kappaB pathways or treatment with Wortmannin also reduced the IL-12 response to intact Gram-positive bacteria. LPS induced moderate levels of IL-12 (0.31 ng/ml), but only from IFN-gamma pre-treated PBMC. This IL-12 production was enhanced by Wortmannin and unaffected by blocking the JNK pathway. Thus, intact Gram-positive bacteria trigger monocyte production of large amounts of IL-12 via a distinct pathway that is turned off by fragmented Gram-positive bacteria. This may be a physiological feedback, since such fragments may signal that further activation of the phagocyte via the IL-12/IFN-gamma loop is unnecessary. PMID:18832044

Barkman, Cecilia; Martner, Anna; Hessle, Christina; Wold, Agnes E

2008-01-01

52

The lifestyle of Streptomyces, a genus of Gram-positive bacteria that belongs to the phylum Actinobacteria,  

E-print Network

The lifestyle of Streptomyces, a genus of Gram-positive bacteria that belongs to the phylum Streptomyces spp. also successfully inhabit a wide range of other niches, both terrestrial and aquatic metabolism of Streptomyces has made these organisms valuable providers of anti- biotics and other bioactive

Buttner, Mark

53

Effect of betamethasone in combination with antibiotics on gram positive and gram negative bacteria.  

PubMed

Betamethasone is an anti-inflammatory steroid drug used in cases of anaphylactic and allergic reactions, of Alzheimer and Addison diseases and in soft tissue injuries. It modulates gene expression for anti-inflammatory activity suppressing the immune system response. This latter effect might decrease the effectiveness of immune system response against microbial infections. Corticosteroids, in fact, mask some symptoms of infection and during their use superimposed infections may occur. Thus, the use of glucocorticoids in patients with sepsis remains extremely controversial. In this study we analyzed the in vitro effect of a commercial formulation of betamethasone (Bentelan) on several Gram positive and Gram negative bacteria of clinical relevance. It was found to be an inhibitor of the growth of most of the strains examined. Also the effect of betamethasone in combination with some classes of antibiotics was evaluated. Antibiotic-steroid combination therapy is, in such cases, superior to antibiotic-alone treatment to impair bacterial growths. Such effect was essentially not at all observable on Staphylococcus aureus or Coagulase Negative Staphylococci (CoNS). PMID:25572750

Artini, M; Papa, R; Cellini, A; Tilotta, M; Barbato, G; Koverech, A; Selan, L

2014-01-01

54

Combination of Pantothenamides with Vanin Inhibitors as a Novel Antibiotic Strategy against Gram-Positive Bacteria  

PubMed Central

The emergence of resistance against current antibiotics calls for the development of new compounds to treat infectious diseases. Synthetic pantothenamides are pantothenate analogs that possess broad-spectrum antibacterial activity in vitro in minimal media. Pantothenamides were shown to be substrates of the bacterial coenzyme A (CoA) biosynthetic pathway, causing cellular CoA depletion and interference with fatty acid synthesis. In spite of their potential use and selectivity for bacterial metabolic routes, these compounds have never made it to the clinic. In the present study, we show that pantothenamides are not active as antibiotics in the presence of serum, and we found that they were hydrolyzed by ubiquitous pantetheinases of the vanin family. To address this further, we synthesized a series of pantetheinase inhibitors based on a pantothenate scaffold that inhibited serum pantetheinase activity in the nanomolar range. Mass spectrometric analysis showed that addition of these pantetheinase inhibitors prevented hydrolysis of pantothenamides by serum. We found that combinations of these novel pantetheinase inhibitors and prototypic pantothenamides like N5-Pan and N7-Pan exerted antimicrobial activity in vitro, particularly against Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Streptococcus pyogenes) even in the presence of serum. These results indicate that pantothenamides, when protected against degradation by host pantetheinases, are potentially useful antimicrobial agents. PMID:23877685

Jansen, Patrick A. M.; Hermkens, Pedro H. H.; Zeeuwen, Patrick L. J. M.; Botman, Peter N. M.; Blaauw, Richard H.; Burghout, Peter; van Galen, Peter M.; Mouton, Johan W.; Rutjes, Floris P. J. T.

2013-01-01

55

Combination of pantothenamides with vanin inhibitors as a novel antibiotic strategy against gram-positive bacteria.  

PubMed

The emergence of resistance against current antibiotics calls for the development of new compounds to treat infectious diseases. Synthetic pantothenamides are pantothenate analogs that possess broad-spectrum antibacterial activity in vitro in minimal media. Pantothenamides were shown to be substrates of the bacterial coenzyme A (CoA) biosynthetic pathway, causing cellular CoA depletion and interference with fatty acid synthesis. In spite of their potential use and selectivity for bacterial metabolic routes, these compounds have never made it to the clinic. In the present study, we show that pantothenamides are not active as antibiotics in the presence of serum, and we found that they were hydrolyzed by ubiquitous pantetheinases of the vanin family. To address this further, we synthesized a series of pantetheinase inhibitors based on a pantothenate scaffold that inhibited serum pantetheinase activity in the nanomolar range. Mass spectrometric analysis showed that addition of these pantetheinase inhibitors prevented hydrolysis of pantothenamides by serum. We found that combinations of these novel pantetheinase inhibitors and prototypic pantothenamides like N5-Pan and N7-Pan exerted antimicrobial activity in vitro, particularly against Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Streptococcus pyogenes) even in the presence of serum. These results indicate that pantothenamides, when protected against degradation by host pantetheinases, are potentially useful antimicrobial agents. PMID:23877685

Jansen, Patrick A M; Hermkens, Pedro H H; Zeeuwen, Patrick L J M; Botman, Peter N M; Blaauw, Richard H; Burghout, Peter; van Galen, Peter M; Mouton, Johan W; Rutjes, Floris P J T; Schalkwijk, Joost

2013-10-01

56

Susceptibility of Gram-positive and -negative bacteria to novel nitric oxide-releasing nanoparticle technology.  

PubMed

The rapidly evolving crisis of antibiotic resistance among microorganisms has contributed to the rise of patient morbidity and mortality from nosocomial and community-acquired infections. Therefore, innovative antimicrobial technology targeting mechanisms to which the bacteria are unlikely to evolve resistance is urgently needed. We have previously described a nitric oxide-releasing nanoparticle (NO-np) with efficacy against methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii in vitro and in murine wound and abscess models. Although the prior findings suggest that the NO-np can be a useful therapeutic for skin and soft tissue infections, the antimicrobial spectrum of NO-np has yet to be fully elucidated. In the current study, we investigated the efficacy of a NO-np against several Gram-positive and -negative clinical isolates. We found that the NO-np were uniformly active against all of the Streptococcus pyogenes, Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa clinical isolates examined, including strains that were both sensitive and resistant to commonly used antibiotics. We concluded that the NO-np have the potential to serve as a novel broad spectrum antimicrobial agent. PMID:21577055

Friedman, Adam; Blecher, Karin; Sanchez, David; Tuckman-Vernon, Chaim; Gialanella, Philip; Friedman, Joel M; Martinez, Luis R; Nosanchuk, Joshua D

2011-01-01

57

Antimicrobial ent-pimarane diterpenes from Viguiera arenaria against Gram-positive bacteria.  

PubMed

The dichloromethane crude extract from the roots of Viguiera arenaria (VaDRE) has been employed in an antimicrobial screening against several bacteria responsible for human pathologies. The main diterpenes isolated from this extract, as well as two semi-synthetic pimarane derivatives, were also investigated for the pathogens that were significantly inhibited by the extract (MIC values lower than 100 microg mL(-1)). The VaDRE extract was significantly active only against Gram-positive microorganisms. The compounds ent-pimara-8(14),15-dien-19-oic acid (PA); PA sodium salt; ent-8(14),15-pimaradien-3beta-ol; ent-15-pimarene-8 beta,19-diol; and ent-8(14),15-pimaradien-3beta-acetoxy displayed the highest antibacterial activities (MIC values lower than 10 microg mL(-1) for most pathogens). In conclusion, our results suggest that pimaranes are an important class of natural products for further investigations in the search of new antibacterial agents. PMID:19524643

Porto, Thiago Souza; Furtado, Niege A J C; Heleno, Vladimir C G; Martins, Carlos H G; Da Costa, Fernando B; Severiano, Marcela E; Silva, Aline N; Veneziani, Rodrigo C S; Ambrósio, Sérgio R

2009-10-01

58

Cultivation of aerobic chemoorganotrophic proteobacteria and gram-positive bacteria from a hot spring microbial mat.  

PubMed Central

The diversity of aerobic chemoorganotrophic bacteria inhabiting the Octopus Spring cyanobacterial mat community (Yellowstone National Park) was examined by using serial-dilution enrichment culture and a variety of enrichment conditions to cultivate the numerically significant microbial populations. The most abundant bacterial populations cultivated from dilutions to extinction were obtained from enrichment flasks which contained 9.0 x 10(2) primary producer (Synechococcus spp.) cells in the inoculum. Two isolates exhibited 16S rRNA nucleotide sequences typical of beta-proteobacteria. One of these isolates contained a 16S rRNA sequence identical to a sequence type previously observed in the mat by molecular retrieval techniques. Both are distantly related to a new sequence directly retrieved from the mat and contributed by a beta-proteobacterial community member. Phenotypically diverse gram-positive isolates genetically similar to Bacillus flavothermus were obtained from a variety of dilutions and enrichment types. These isolates exhibited identical 16S rRNA nucleotide sequences through a variable region of the molecule. Of the three unique sequences observed, only one had been previously retrieved from the mat, illustrating both the inability of the cultivation methods to describe the composition of a microbial community and the limitations of the ability of molecular retrieval techniques to describe populations which may be less abundant in microbial communities. PMID:8899976

Nold, S C; Kopczynski, E D; Ward, D M

1996-01-01

59

Recognition of Gram-positive Intestinal Bacteria by Hybridoma- and Colostrum-derived Secretory Immunoglobulin A Is Mediated by Carbohydrates*  

PubMed Central

Humans live in symbiosis with 1014 commensal bacteria among which >99% resides in their gastrointestinal tract. The molecular bases pertaining to the interaction between mucosal secretory IgA (SIgA) and bacteria residing in the intestine are not known. Previous studies have demonstrated that commensals are naturally coated by SIgA in the gut lumen. Thus, understanding how natural SIgA interacts with commensal bacteria can provide new clues on its multiple functions at mucosal surfaces. Using fluorescently labeled, nonspecific SIgA or secretory component (SC), we visualized by confocal microscopy the interaction with various commensal bacteria, including Lactobacillus, Bifidobacteria, Escherichia coli, and Bacteroides strains. These experiments revealed that the interaction between SIgA and commensal bacteria involves Fab- and Fc-independent structural motifs, featuring SC as a crucial partner. Removal of glycans present on free SC or bound in SIgA resulted in a drastic drop in the interaction with Gram-positive bacteria, indicating the essential role of carbohydrates in the process. In contrast, poor binding of Gram-positive bacteria by control IgG was observed. The interaction with Gram-negative bacteria was preserved whatever the molecular form of protein partner used, suggesting the involvement of different binding motifs. Purified SIgA and SC from either mouse hybridoma cells or human colostrum exhibited identical patterns of recognition for Gram-positive bacteria, emphasizing conserved plasticity between species. Thus, sugar-mediated binding of commensals by SIgA highlights the currently underappreciated role of glycans in mediating the interaction between a highly diverse microbiota and the mucosal immune system. PMID:21454510

Mathias, Amandine; Corthésy, Blaise

2011-01-01

60

Antimicrobial Activities of Leaf Extracts of Guava (Psidium guajava L.) on Two Gram-Negative and Gram-Positive Bacteria  

PubMed Central

Aim. To determine the antimicrobial potential of guava (Psidium guajava) leaf extracts against two gram-negative bacteria (Escherichia coli and Salmonella enteritidis) and two gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) which are some of foodborne and spoilage bacteria. The guava leaves were extracted in four different solvents of increasing polarities (hexane, methanol, ethanol, and water). The efficacy of these extracts was tested against those bacteria through a well-diffusion method employing 50??L leaf-extract solution per well. According to the findings of the antibacterial assay, the methanol and ethanol extracts of the guava leaves showed inhibitory activity against gram-positive bacteria, whereas the gram-negative bacteria were resistant to all the solvent extracts. The methanol extract had an antibacterial activity with mean zones of inhibition of 8.27 and 12.3?mm, and the ethanol extract had a mean zone of inhibition of 6.11 and 11.0?mm against B. cereus and S. aureus, respectively. On the basis of the present finding, guava leaf-extract might be a good candidate in the search for a natural antimicrobial agent. This study provides scientific understanding to further determine the antimicrobial values and investigate other pharmacological properties. PMID:24223039

Biswas, Bipul; Rogers, Kimberly; McLaughlin, Fredrick; Yadav, Anand

2013-01-01

61

Palmitoleic Acid Isomer (C16:1?6) in Human Skin Sebum Is Effective against Gram-Positive Bacteria  

Microsoft Academic Search

The percent lipid composition of pooled human sebum analyzed by thin-layer chromatography was: ceramides (13%), fatty acid (47%), cholesterol (7%), cholesterol esters (2%), squalene (11%), triglycerides (3%), and wax esters (17%). Total sebum lipids (2– 4 mg\\/ml), sonicated into bacterial culture medium, caused 4- to 5-fold log reduction in growth of gram-positive bacteria, Staphylococcus aureus, Streptococcus salivarius and the anaerobe

J. J. Wille; A. Kydonieus

2003-01-01

62

In Vitro Activity of Ozenoxacin against Quinolone-Susceptible and Quinolone-Resistant Gram-Positive Bacteria  

PubMed Central

In vitro activity of ozenoxacin, a novel nonfluorinated topical (L. D. Saravolatz and J. Leggett, Clin. Infect. Dis. 37:1210–1215, 2003) quinolone, was compared with the activities of other quinolones against well-characterized quinolone-susceptible and quinolone-resistant Gram-positive bacteria. Ozenoxacin was 3-fold to 321-fold more active than other quinolones. Ozenoxacin could represent a first-in-class nonfluorinated quinolone for the topical treatment of a broad range of dermatological infections. PMID:24080666

López, Y.; Tato, M.; Espinal, P.; Garcia-Alonso, F.; Gargallo-Viola, D.; Cantón, R.

2013-01-01

63

Soluble bacterial constituents down-regulate secretion of IL12 in response to intact Gram-positive bacteria  

Microsoft Academic Search

Intact Gram-positive bacteria induce production of large amounts of IL-12 from freshly isolated human monocytes. Here the bacterial structures and signalling pathways involved were studied and compared with those leading to IL-6 production, and to IL-12 production in response to LPS after IFN-? pre-treatment. Intact bifidobacteria induced massive production of IL-12 (1ng\\/ml) and IL-6 (>30ng\\/ml) from human PBMC, whereas fragmented

Cecilia Barkman; Anna Martner; Christina Hessle; Agnes E. Wold

2008-01-01

64

Detection of and Discrimination between Gram-Positive and Gram-Negative Bacteria in Intraocular Samples by Using Nested PCR  

Microsoft Academic Search

A nested PCR protocol has been developed for the detection of and discrimination between 14 species of gram-positive and -negative bacteria in samples of ocular fluids. First-round PCR with pan-bacterial oligo- nucleotide primers, based on conserved sequences of the 16S ribosomal gene, was followed by a gram-negative- organism-specific PCR, which resulted in a single 985-bp amplification product, and a multiplex

NORA M. CARROLL; EMMA E. M. JAEGER; SARAH CHOUDHURY; ANTHONY A. S. DUNLOP; MELVILLE M. MATHESON; PETER ADAMSON; NARCISS OKHRAVI; SUSAN LIGHTMAN

2000-01-01

65

Genetic determinants of antimicrobial resistance in Gram positive bacteria from organic foods.  

PubMed

Bacterial biocide resistance is becoming a matter of concern. In the present study, a collection of biocide-resistant, Gram-positive bacteria from organic foods (including 11 isolates from genus Bacillus, 25 from Enterococcus and 10 from Staphylococcus) were analyzed for genes associated to biocide resistance efflux pumps and antibiotic resistance. The only qac-genes detected were qacA/B (one Bacillus cereus isolate) and smr (one B. cereus and two Staphylococcus saprophyticus isolates). Efflux pump genes efrA and efrB genes were detected in Staphylococcus (60% of isolates), Bacillus (54.54%) and Enterococcus (24%); sugE was detected in Enterococcus (20%) and in one Bacillus licheniformis; mepA was detected in Staphylococcus (60%) and in one Enterococcus isolate (which also carried mdeA), and norE gene was detected only in one Enterococcus faecium and one S. saprophyticus isolate. An amplicon for acrB efflux pump was detected in all but one isolate. When minimal inhibitory concentrations (MICs) were determined, it was found that the addition of reserpine reduced the MICs by eight fold for most of the biocides and isolates, corroborating the role of efflux pumps in biocide resistance. Erythromycin resistance gene ermB was detected in 90% of Bacillus isolates, and in one Staphylococcus, while ereA was detected only in one Bacillus and one Staphyloccus, and ereB only in one Staphylococcus. The ATP-dependent msrA gene (which confers resistance to macrolides, lincosamides and type B streptogramins) was detected in 60% of Bacillus isolates and in all staphylococci, which in addition carried msrB. The lincosamide and streptogramin A resistance gene lsa was detected in Staphylococcus (40%), Bacillus (27.27%) and Enterococcus (8%) isolates. The aminoglycoside resistance determinant aph (3_)-IIIa was detected in Staphylococcus (40%) and Bacillus (one isolate), aph(2_)-1d in Bacillus (27.27%) and Enterococcus (8%), aph(2_)-Ib in Bacillus (one isolate), and the bifunctional aac(6_)1e-aph(2_)-Ia in Staphylococcus (20%), Enterococcus (8%) and Bacillus (one isolate). Chloramphenicol resistance cat gene was detected in Enterococcus (8%) and Staphylococcus (20%), and blaZ only in Staphylococcus (20%). All other antibiotic or biocide resistance genes investigated were not detected in any isolate. Isolates carrying multiple biocide and antibiotic determinants were frequent among Bacillus (36.36%) and Staphylococcus (50%), but not Enterococcus. These results suggest that biocide and antibiotic determinants may be co-selected. PMID:24361832

Fernández-Fuentes, Miguel Angel; Abriouel, Hikmate; Ortega Morente, Elena; Pérez Pulido, Rubén; Gálvez, Antonio

2014-02-17

66

Antimicrobial-resistant gram-positive bacteria in PD peritonitis and the newer antibiotics used to treat them.  

PubMed

The incidence of resistant gram-positive bacteria in nosocomial and, more recently, community-acquired infections is increasing. Staphylococci, because of their natural habitat on the skin, have always been the leading cause of peritonitis in patients receiving peritoneal dialysis (PD). These organisms have demonstrated a remarkable ability to develop resistance to antibiotics, first with penicillin, then antistaphylococcal penicillins (methicillin-resistant Staphylococcus aureus), and more recently, strains expressing resistance to vancomycin (vancomycin-intermediate and vancomycin-resistant S. aureus) have emerged. Enterococci are normal inhabitants of the gastrointestinal tract and occasionally cause PD peritonitis. In the past 15 years, vancomycin-resistant enterococci have emerged as significant pathogens in many areas. In the past 5 years, novel antibiotics that have activity on gram-positive bacteria, including vancomycin-resistant strains, have become available. The problem of resistant gram-positive bacteria in PD peritonitis, their therapy, and the role of these newer agents, quinupristin/dalfopristin, linezolid, and daptomycin, are reviewed. PMID:16022084

Salzer, William

2005-01-01

67

Competitive adsorption of metal cations onto two gram positive bacteria: testing the chemical equilibrium model  

Microsoft Academic Search

In order to test the ability of a surface complexation approach to account for metal-bacteria interactions in near surface fluid-rock systems, we have conducted experiments that measure the extent of adsorption in mixed metal, mixed bacteria systems. This study tests the surface complexation approach by comparing estimated extents of adsorption based on surface complexation modeling to those we observed in

David A. Fowle; Jeremy B. Fein

1999-01-01

68

Antimicrobial activity of metal oxide nanoparticles against Gram-positive and Gram-negative bacteria: a comparative study  

PubMed Central

Background Nanomaterials have unique properties compared to their bulk counterparts. For this reason, nanotechnology has attracted a great deal of attention from the scientific community. Metal oxide nanomaterials like ZnO and CuO have been used industrially for several purposes, including cosmetics, paints, plastics, and textiles. A common feature that these nanoparticles exhibit is their antimicrobial behavior against pathogenic bacteria. In this report, we demonstrate the antimicrobial activity of ZnO, CuO, and Fe2O3 nanoparticles against Gram-positive and Gram-negative bacteria. Methods and results Nanosized particles of three metal oxides (ZnO, CuO, and Fe2O3) were synthesized by a sol–gel combustion route and characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and transmission electron microscopy techniques. X-ray diffraction results confirmed the single-phase formation of all three nanomaterials. The particle sizes were observed to be 18, 22, and 28 nm for ZnO, CuO, and Fe2O3, respectively. We used these nanomaterials to evaluate their antibacterial activity against both Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria. Conclusion Among the three metal oxide nanomaterials, ZnO showed greatest antimicrobial activity against both Gram-positive and Gram-negative bacteria used in this study. It was observed that ZnO nanoparticles have excellent bactericidal potential, while Fe2O3 nanoparticles exhibited the least bactericidal activity. The order of antibacterial activity was demonstrated to be the following: ZnO > CuO > Fe2O3. PMID:23233805

Azam, Ameer; Ahmed, Arham S; Oves, Mohammad; Khan, Mohammad S; Habib, Sami S; Memic, Adnan

2012-01-01

69

Antimicrobial and Efflux Pump Inhibitory Activity of Caffeoylquinic Acids from Artemisia absinthium against Gram-Positive Pathogenic Bacteria  

PubMed Central

Background Traditional antibiotics are increasingly suffering from the emergence of multidrug resistance amongst pathogenic bacteria leading to a range of novel approaches to control microbial infections being investigated as potential alternative treatments. One plausible antimicrobial alternative could be the combination of conventional antimicrobial agents/antibiotics with small molecules which block multidrug efflux systems known as efflux pump inhibitors. Bioassay-driven purification and structural determination of compounds from plant sources have yielded a number of pump inhibitors which acted against gram positive bacteria. Methodology/Principal Findings In this study we report the identification and characterization of 4?,5?-O-dicaffeoylquinic acid (4?,5?-ODCQA) from Artemisia absinthium as a pump inhibitor with a potential of targeting efflux systems in a wide panel of Gram-positive human pathogenic bacteria. Separation and identification of phenolic compounds (chlorogenic acid, 3?,5?-ODCQA, 4?,5?-ODCQA) was based on hyphenated chromatographic techniques such as liquid chromatography with post column solid-phase extraction coupled with nuclear magnetic resonance spectroscopy and mass spectroscopy. Microbial susceptibility testing and potentiation of well know pump substrates revealed at least two active compounds; chlorogenic acid with weak antimicrobial activity and 4?,5?-ODCQA with pump inhibitory activity whereas 3?,5?-ODCQA was ineffective. These intitial findings were further validated with checkerboard, berberine accumulation efflux assays using efflux-related phenotypes and clinical isolates as well as molecular modeling methodology. Conclusions/Significance These techniques facilitated the direct analysis of the active components from plant extracts, as well as dramatically reduced the time needed to analyze the compounds, without the need for prior isolation. The calculated energetics of the docking poses supported the biological information for the inhibitory capabilities of 4?,5?-ODCQA and furthermore contributed evidence that CQAs show a preferential binding to Major Facilitator Super family efflux systems, a key multidrug resistance determinant in gram-positive bacteria. PMID:21483731

Fiamegos, Yiannis C.; Kastritis, Panagiotis L.; Exarchou, Vassiliki; Han, Haley; Bonvin, Alexandre M. J. J.; Vervoort, Jacques; Lewis, Kim; Hamblin, Michael R.; Tegos, George P.

2011-01-01

70

In vitro activity of the tribactam GV104326 against gram-positive, gram-negative, and anaerobic bacteria.  

PubMed Central

GV104326 is the first member of a new class of antibiotics (tribactams) selected for development. It combines a particularly broad spectrum (including gram-negative and gram-positive aerobes and anaerobes) with high potency, resistance to beta-lactamases, and complete stability to dehydropeptidases. Comparative MICs were determined for GV104326 against 415 recent clinical isolates (including beta-lactamase producers), using representative antibacterial agents (imipenem, amoxicillin-clavulanic acid, cefpirome, ciprofloxacin, gentamicin, and erythromycin). GV104326 was particularly active against gram-positive bacteria; in general, its in vitro activity was equivalent to that of imipenem, equivalent to or better than that of amoxicillin-clavulanic acid, and superior to that of cefpirome, ciprofloxacin, and erythromycin. Against gram-negative bacteria, GV104326 possessed activity similar to that of imipenem and cefpirome against enterobacteria and Haemophilus spp. but its activity was superior to that of amoxicillin-clavulanic acid. GV104326 showed excellent antianaerobe activity. GV104326 was stable to all clinically relevant beta-lactamases and was rapidly lethal to susceptible bacteria. In Escherichia coli, GV104326 bound predominantly to PBPs 1a and 2 and at low concentrations osmotically stable round forms were observed. GV104326 showed an affinity for PBPs 2 and 4 of Staphylococcus aureus. PMID:7840571

Di Modugno, E; Erbetti, I; Ferrari, L; Galassi, G; Hammond, S M; Xerri, L

1994-01-01

71

Production of a bacteriocin by a poultry derived Campylobacter jejuni isolate with antimicrobial activity against Clostridium perfringens and other Gram positive bacteria.  

Technology Transfer Automated Retrieval System (TEKTRAN)

We have purified a bacteriocin peptide (termed CUV-3), produced by a poultry cecal isolate of Campylobacter jejuni (strain CUV-3) with inhibitory activity against Gram positive bacteria including Clostridium perfringens (38 strains), Staphylococcus aureus, Staphylococcus epidermidis and Listeria mon...

72

Modeling of rare earth element sorption to the Gram positive Bacillus subtilis bacteria surface.  

PubMed

In this study, rare earth element (REE) binding constants and site concentration on the Gram+ bacteria surfaces were quantified using a multi-site Langmuir isotherm model, along with a linear programming regression method (LPM), applied to fit experimental REE sorption data. This approach found one discrete REE binding site on the Gram+ Bacillus subtilis surface for the pH range of 2.5-4.5. Average log10 REE binding constants for a site j on these bacteria ranged from 1.08±0.04 to 1.40±0.04 for the light REE (LREE: La to Eu), and from 1.36±0.03 to 2.18±0.14 for the heavy REE (HREE: Gd to Lu) at the highest biomass concentration of 1.3 g/L of B. subtilis bacteria. Similar values were obtained for bacteria concentrations of 0.39 and 0.67 g/L indicating the independence of REE sorption constants on biomass concentration. Within the experimental pH range in this study, B. subtilis was shown to have a lower affinity for LREE (e.g. La, Ce, Pr, Nd) and a higher affinity for HREE (e.g. Tm, Yb, Lu) suggesting an enrichment of HREE on the surface of Gram+ bacteria. Total surface binding site concentrations of 6.73±0.06 to 5.67±0.06 and 5.53±0.07 to 4.54±0.03 mol/g of bacteria were observed for LREE and HREE respectively, with the exception of Y, which showed a total site concentration of 9.53±0.03, and a log K(REE,j) of 1.46±0.02 for a biomass content of 1.3 g/L. The difference in these values (e.g. a lower affinity and increased binding site concentration for LREE, and the contrary for the HREE) suggests a distinction between the LREE and HREE binding modes to the Gram+ bacteria reactive surface at low pH. This further implies that HREE may bind more than one monoprotic reactive group on the cell surface. A multisite Langmuir isotherm approach along with the LPM regression method, not requiring prior knowledge of the number or concentration of cell surface REE complexation sites, were able to distinguish between the sorption constant and binding site concentration patterns of LREE and HREE on the Gram+ B. subtilis surface. This approach quantified the enrichment of Tm, Yb and Lu on the bacteria surface and it has therefore proven to be a useful tool for the study of natural reactive sorbent materials controlling REE partitioning in the natural environment. PMID:24183437

Martinez, Raul E; Pourret, Olivier; Takahashi, Yoshio

2014-01-01

73

Assessment of the in vitro Efficacy of the Novel Antimicrobial Peptide CECT7121 against Human Gram-Positive Bacteria from Serious Infections Refractory to Treatment  

Microsoft Academic Search

Background: Resistant Gram-positive bacteria are causing increasing concern in clinical practice. This work investigated theefficacy of AP-CECT7121 (an antimicrobial peptide isolated from an environmental strain of Enterococcus faecalis CECT7121) against various pathogenic Gram-positive bacteria. Methods: Strains were isolated from intensive care unit patients unresponsive to standard antibiotic treatments. Inhibitory activity of AP-CECT7121 was assessed using the agar-well diffusion method. The

M. D. Sparo; D. G. Jones; S. F. Sánchez Bruni

2009-01-01

74

Surface multiheme c-type cytochromes from Thermincola potens: Implications for dissimilatory metal reduction by Gram-positive bacteria  

NASA Astrophysics Data System (ADS)

Almost nothing is known about the mechanisms of dissimilatory metal reduction by Gram-positive bacteria, although they have been shown to be the dominant species in some environments. Thermincola potens strain JR was isolated from the anode of a microbial fuel cell inoculated with anaerobic digester sludge and operated at 55 °C. Preliminary characterization revealed that T. potens coupled acetate oxidation to the reduction of hydrous ferric oxides (HFO) or the humic substances analog, anthraquinone-2,6-disulfonate (AQDS). The genome of T. potens was recently sequenced, and the abundance of multiheme c-type cytochromes (MHCs) is unusual for a Gram-positive bacterium. We present evidence from trypsin shaving LC-MS/MS experiments and surface-enhanced Raman spectroscopy (SERS) that indicates the expression of a number of MHCs during T. potens growth on either HFO or AQDS and that several MHCs are localized to the cell wall or cell surface of T. potens. Furthermore, one of the MHCs can be extracted from cells with low pH or denaturants suggesting a loose association with the cell wall or cell surface. Electron microscopy does not reveal an S-layer, and the precipitation of silver metal on the cell surface is inhibited by cyanide, supporting the involvement of surface-localized redox-active heme proteins in dissimilatory metal reduction. These results are the first direct evidence for cell-wall associated cytochromes and MHC involvement in conducting electrons across the cell envelope of a Gram-positive bacterium.

Carlson, H. K.; Iavarone, A. T.; Gorur, A.; Yeo, B. S.; Tran, R.; Melnyk, R. A.; Mathies, R. A.; Auer, M.; Coates, J. D.

2011-12-01

75

Plants used in Guatemala for the treatment of respiratory diseases. 1. Screening of 68 plants against gram-positive bacteria.  

PubMed

Respiratory ailments are important causes of morbidity and mortality in developing countries. Ethnobotanical surveys and literature reviews conducted in Guatemala during 1986-88 showed that 234 plants from 75 families, most of them of American origin, have been used for the treatment of respiratory ailments. Three Gram-positive bacteria causing respiratory infections (Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus pyogenes) were used to screen 68 of the most commonly used plants for activity. Twenty-eight of these (41.2%) inhibited the growth of one or more of the bacteria tested. Staphylococcus aureus was inhibited by 18 of the plant extracts, while 7 extracts were effective against Streptococcus pyogenes. Plants of American origin which exhibited antibacterial activity were: Gnaphalium viscosum, Lippia alba, Lippia dulcis, Physalis philadelphica, Satureja brownei, Solanum nigrescens and Tagetes lucida. These preliminary in vitro results provide scientific basis for the use of these plants against bacterial respiratory infections. PMID:2023428

Caceres, A; Alvarez, A V; Ovando, A E; Samayoa, B E

1991-02-01

76

A super-family of transcriptional activators regulates bacteriophage packaging and lysis in Gram-positive bacteria  

PubMed Central

The propagation of bacteriophages and other mobile genetic elements requires exploitation of the phage mechanisms involved in virion assembly and DNA packaging. Here, we identified and characterized four different families of phage-encoded proteins that function as activators required for transcription of the late operons (morphogenetic and lysis genes) in a large group of phages infecting Gram-positive bacteria. These regulators constitute a super-family of proteins, here named late transcriptional regulators (Ltr), which share common structural, biochemical and functional characteristics and are unique to this group of phages. They are all small basic proteins, encoded by genes present at the end of the early gene cluster in their respective phage genomes and expressed under cI repressor control. To control expression of the late operon, the Ltr proteins bind to a DNA repeat region situated upstream of the terS gene, activating its transcription. This involves the C-terminal part of the Ltr proteins, which control specificity for the DNA repeat region. Finally, we show that the Ltr proteins are the only phage-encoded proteins required for the activation of the packaging and lysis modules. In summary, we provide evidence that phage packaging and lysis is a conserved mechanism in Siphoviridae infecting a wide variety of Gram-positive bacteria. PMID:23771138

Quiles-Puchalt, Nuria; Tormo-Más, María Ángeles; Campoy, Susana; Toledo-Arana, Alejandro; Monedero, Vicente; Lasa, Íñigo; Novick, Richard P.; Christie, Gail E.; Penadés, José R.

2013-01-01

77

Performances of VITEK 2 Colorimetric Cards for Identification of Gram-Positive and Gram-Negative Bacteria  

PubMed Central

Thepurpose of this study was to evaluate the new VITEK 2 identification cards that use colorimetric reading to identify gram-positive and gram-negative bacteria (GP and GN cards, respectively) in comparison to fluorimetric cards (ID-GPC and ID-GNB, respectively). A total of 580 clinical isolates and stock collection strains belonging to 116 taxa were included in the study. Of the 249 gram-positive strains tested with both the ID-GPC and GP cards, 218 (87.5%) and 235 (94.4%) strains were correctly identified (to the genus and species level), respectively. Of the 331 gram-negative strains tested with the ID-GNB and GN cards, 295 (89.1%) and 321 (97%) strains were correctly identified, respectively. Another focus of the study was to apply the percentages of correct identifications obtained in this study to the list of bacteria isolated in our laboratory (32,739 isolates) in the year 2004. We obtained 97.9% correct identifications with the colorimetric cards and 93.9% with fluorescent cards. PMID:16145083

Wallet, Frédéric; Loïez, Caroline; Renaux, Emilie; Lemaitre, Nadine; Courcol, René J.

2005-01-01

78

Surface Proteins of Gram-Positive Bacteria and Mechanisms of Their Targeting to the Cell Wall Envelope  

PubMed Central

The cell wall envelope of gram-positive bacteria is a macromolecular, exoskeletal organelle that is assembled and turned over at designated sites. The cell wall also functions as a surface organelle that allows gram-positive pathogens to interact with their environment, in particular the tissues of the infected host. All of these functions require that surface proteins and enzymes be properly targeted to the cell wall envelope. Two basic mechanisms, cell wall sorting and targeting, have been identified. Cell well sorting is the covalent attachment of surface proteins to the peptidoglycan via a C-terminal sorting signal that contains a consensus LPXTG sequence. More than 100 proteins that possess cell wall-sorting signals, including the M proteins of Streptococcus pyogenes, protein A of Staphylococcus aureus, and several internalins of Listeria monocytogenes, have been identified. Cell wall targeting involves the noncovalent attachment of proteins to the cell surface via specialized binding domains. Several of these wall-binding domains appear to interact with secondary wall polymers that are associated with the peptidoglycan, for example teichoic acids and polysaccharides. Proteins that are targeted to the cell surface include muralytic enzymes such as autolysins, lysostaphin, and phage lytic enzymes. Other examples for targeted proteins are the surface S-layer proteins of bacilli and clostridia, as well as virulence factors required for the pathogenesis of L. monocytogenes (internalin B) and Streptococcus pneumoniae (PspA) infections. In this review we describe the mechanisms for both sorting and targeting of proteins to the envelope of gram-positive bacteria and review the functions of known surface proteins. PMID:10066836

Navarre, William Wiley; Schneewind, Olaf

1999-01-01

79

Surface roughness mediated adhesion forces between borosilicate glass and gram-positive bacteria.  

PubMed

It is well-known that a number of surface characteristics affect the extent of adhesion between two adjacent materials. One of such parameters is the surface roughness as surface asperities at the nanoscale level govern the overall adhesive forces. For example, the extent of bacterial adhesion is determined by the surface topography; also, once a bacteria colonizes a surface, proliferation of that species will take place and a biofilm may form, increasing the resistance of bacterial cells to removal. In this study, borosilicate glass was employed with varying surface roughness and coated with bovine serum albumin (BSA) in order to replicate the protein layer that covers orthopedic devices on implantation. As roughness is a scale-dependent process, relevant scan areas were analyzed using atomic force microscope (AFM) to determine Ra; furthermore, appropriate bacterial species were attached to the tip to measure the adhesion forces between cells and substrates. The bacterial species chosen (Staphylococci and Streptococci) are common pathogens associated with a number of implant related infections that are detrimental to the biomedical devices and patients. Correlation between adhesion forces and surface roughness (Ra) was generally better when the surface roughness was measured through scanned areas with size (2 × 2 ?m) comparable to bacteria cells. Furthermore, the BSA coating altered the surface roughness without correlation with the initial values of such parameter; therefore, better correlations were found between adhesion forces and BSA-coated surfaces when actual surface roughness was used instead of the initial (nominal) values. It was also found that BSA induced a more hydrophilic and electron donor characteristic to the surfaces; in agreement with increasing adhesion forces of hydrophilic bacteria (as determined through microbial adhesion to solvents test) on BSA-coated substrates. PMID:25019516

Preedy, Emily; Perni, Stefano; Nipi?, Damijan; Bohinc, Klemen; Prokopovich, Polina

2014-08-12

80

Desulfotomaculum spp. and related gram-positive sulfate-reducing bacteria in deep subsurface environments  

PubMed Central

Gram-positive spore-forming sulfate reducers and particularly members of the genus Desulfotomaculum are commonly found in the subsurface biosphere by culture based and molecular approaches. Due to their metabolic versatility and their ability to persist as endospores. Desulfotomaculum spp. are well-adapted for colonizing environments through a slow sedimentation process. Because of their ability to grow autotrophically (H2/CO2) and produce sulfide or acetate, these microorganisms may play key roles in deep lithoautotrophic microbial communities. Available data about Desulfotomaculum spp. and related species from studies carried out from deep freshwater lakes, marine sediments, oligotrophic and organic rich deep geological settings are discussed in this review. PMID:24348471

Aüllo, Thomas; Ranchou-Peyruse, Anthony; Ollivier, Bernard; Magot, Michel

2013-01-01

81

A Newly Discovered Bacteroides Conjugative Transposon, CTnGERM1, Contains Genes Also Found in Gram-Positive Bacteria  

PubMed Central

Results of a recent study of antibiotic resistance genes in human colonic Bacteroides strains suggested that gene transfer events between members of this genus are fairly common. The identification of Bacteroides isolates that carried an erythromycin resistance gene, ermG, whose DNA sequence was 99% identical to that of an ermG gene found previously only in gram-positive bacteria raised the further possibility that conjugal elements were moving into Bacteroides species from other genera. Six of seven ermG-containing Bacteroides strains tested were able to transfer ermG by conjugation. One of these strains was chosen for further investigation. Results of pulsed-field gel electrophoresis experiments showed that the conjugal element carrying ermG in this strain is an integrated element about 75 kb in size. Thus, the element appears to be a conjugative transposon (CTn) and was designated CTnGERM1. CTnGERM1 proved to be unrelated to the predominant type of CTn found in Bacteroides isolates—CTns of the CTnERL/CTnDOT family—which sometimes carry another type of erm gene, ermF. A 19-kbp segment of DNA from CTnGERM1 was cloned and sequenced. A 10-kbp portion of this segment hybridized not only to DNA from all the ermG-containing strains but also to DNA from strains that did not carry ermG. Thus, CTnGERM1 seems to be part of a family of CTns, some of which have acquired ermG. The percentage of G+C content of the ermG region was significantly lower than that of the chromosome of Bacteroides species—an indication that CTnGERM1 may have entered Bacteroides strains from some other bacterial genus. A survey of strains isolated before 1970 and after 1990 suggests that the CTnGERM1 type of CTn entered Bacteroides species relatively recently. One of the genes located upstream of ermG encoded a protein that had 85% amino acid sequence identity with a macrolide efflux pump, MefA, from Streptococcus pyogenes. Our having found >90% sequence identity of two upstream genes, including mefA, and the remnants of two transposon-carried genes downstream of ermG with genes found previously only in gram-positive bacteria raises the possibility that gram-positive bacteria could have been the origin of CTnGERM1. PMID:12902247

Wang, Yanping; Wang, Gui-Rong; Shelby, Aikiesha; Shoemaker, Nadja B.; Salyers, Abigail A.

2003-01-01

82

Invariant NKT cells recognize glycolipids from pathogenic Gram-positive bacteria  

PubMed Central

Natural killer T (NKT) cells recognize glycolipid antigens presented by CD1d. These cells express an evolutionarily conserved, invariant T cell receptor (TCR), but the forces driving TCR conservation have remained uncertain. Here we show that NKT cells recognize diacylglycerol-containing glycolipids from Streptococcus pneumoniae, the leading cause of community-acquired pneumonia, and group B Streptococcus, which causes neonatal sepsis and meningitis. Furthermore, CD1d-dependent responses by NKT cells are required for activation and host protection. The glycolipid response was dependent on vaccenic acid, which is found at a low level in mammalian cells. Our results show how microbial lipids position the sugar for recognition by the invariant TCR, and most important, they extend the range of microbes recognized by this conserved TCR to several clinically important bacteria. PMID:21892173

Kinjo, Yuki; Illarionov, Petr; Vela, José Luis; Pei, Bo; Girardi, Enrico; Li, Xiangming; Li, Yali; Imamura, Masakazu; Kaneko, Yukihiro; Okawara, Akiko; Miyazaki, Yoshitsugu; Gómez-Velasco, Anaximandro; Rogers, Paul; Dahesh, Samira; Uchiyama, Satoshi; Khurana, Archana; Kawahara, Kazuyoshi; Yesilkaya, Hasan; Andrew, Peter W.; Wong, Chi-Huey; Kawakami, Kazuyoshi; Nizet, Victor; Besra, Gurdyal S.; Tsuji, Moriya; Zajonc, Dirk M.; Kronenberg, Mitchell

2011-01-01

83

?(ECF) factors of gram-positive bacteria: a focus on Bacillus subtilis and the CMNR group.  

PubMed

The survival of bacteria to different environmental conditions depends on the activation of adaptive mechanisms, which are intricately driven through gene regulation. Because transcriptional initiation is considered to be the major step in the control of bacterial genes, we discuss the characteristics and roles of the sigma factors, addressing (1) their structural, functional and phylogenetic classification; (2) how their activity is regulated; and (3) the promoters recognized by these factors. Finally, we focus on a specific group of alternative sigma factors, the so-called ?(ECF) factors, in Bacillus subtilis and some of the main species that comprise the CMNR group, providing information on the roles they play in the microorganisms' physiology and indicating some of the genes whose transcription they regulate. PMID:24921931

Souza, Bianca Mendes; Castro, Thiago Luiz de Paula; Carvalho, Rodrigo Dias de Oliveira; Seyffert, Nubia; Silva, Artur; Miyoshi, Anderson; Azevedo, Vasco

2014-07-01

84

Antibacterial activity of sphingoid bases and fatty acids against Gram-positive and Gram-negative bacteria.  

PubMed

There is growing evidence that the role of lipids in innate immunity is more important than previously realized. How lipids interact with bacteria to achieve a level of protection, however, is still poorly understood. To begin to address the mechanisms of antibacterial activity, we determined MICs and minimum bactericidal concentrations (MBCs) of lipids common to the skin and oral cavity--the sphingoid bases D-sphingosine, phytosphingosine, and dihydrosphingosine and the fatty acids sapienic acid and lauric acid--against four Gram-negative bacteria and seven Gram-positive bacteria. Exact Kruskal-Wallis tests of these values showed differences among lipid treatments (P < 0.0001) for each bacterial species except Serratia marcescens and Pseudomonas aeruginosa. D-sphingosine (MBC range, 0.3 to 19.6 ?g/ml), dihydrosphingosine (MBC range, 0.6 to 39.1 ?g/ml), and phytosphingosine (MBC range, 3.3 to 62.5 ?g/ml) were active against all bacteria except S. marcescens and P. aeruginosa (MBC > 500 ?g/ml). Sapienic acid (MBC range, 31.3 to 375.0 ?g/ml) was active against Streptococcus sanguinis, Streptococcus mitis, and Fusobacterium nucleatum but not active against Escherichia coli, Staphylococcus aureus, S. marcescens, P. aeruginosa, Corynebacterium bovis, Corynebacterium striatum, and Corynebacterium jeikeium (MBC > 500 ?g/ml). Lauric acid (MBC range, 6.8 to 375.0 ?g/ml) was active against all bacteria except E. coli, S. marcescens, and P. aeruginosa (MBC > 500 ?g/ml). Complete killing was achieved as early as 0.5 h for some lipids but took as long as 24 h for others. Hence, sphingoid bases and fatty acids have different antibacterial activities and may have potential for prophylactic or therapeutic intervention in infection. PMID:22155833

Fischer, Carol L; Drake, David R; Dawson, Deborah V; Blanchette, Derek R; Brogden, Kim A; Wertz, Philip W

2012-03-01

85

Antibacterial Activity of Sphingoid Bases and Fatty Acids against Gram-Positive and Gram-Negative Bacteria  

PubMed Central

There is growing evidence that the role of lipids in innate immunity is more important than previously realized. How lipids interact with bacteria to achieve a level of protection, however, is still poorly understood. To begin to address the mechanisms of antibacterial activity, we determined MICs and minimum bactericidal concentrations (MBCs) of lipids common to the skin and oral cavity—the sphingoid bases d-sphingosine, phytosphingosine, and dihydrosphingosine and the fatty acids sapienic acid and lauric acid—against four Gram-negative bacteria and seven Gram-positive bacteria. Exact Kruskal-Wallis tests of these values showed differences among lipid treatments (P < 0.0001) for each bacterial species except Serratia marcescens and Pseudomonas aeruginosa. d-Sphingosine (MBC range, 0.3 to 19.6 ?g/ml), dihydrosphingosine (MBC range, 0.6 to 39.1 ?g/ml), and phytosphingosine (MBC range, 3.3 to 62.5 ?g/ml) were active against all bacteria except S. marcescens and P. aeruginosa (MBC > 500 ?g/ml). Sapienic acid (MBC range, 31.3 to 375.0 ?g/ml) was active against Streptococcus sanguinis, Streptococcus mitis, and Fusobacterium nucleatum but not active against Escherichia coli, Staphylococcus aureus, S. marcescens, P. aeruginosa, Corynebacterium bovis, Corynebacterium striatum, and Corynebacterium jeikeium (MBC > 500 ?g/ml). Lauric acid (MBC range, 6.8 to 375.0 ?g/ml) was active against all bacteria except E. coli, S. marcescens, and P. aeruginosa (MBC > 500 ?g/ml). Complete killing was achieved as early as 0.5 h for some lipids but took as long as 24 h for others. Hence, sphingoid bases and fatty acids have different antibacterial activities and may have potential for prophylactic or therapeutic intervention in infection. PMID:22155833

Fischer, Carol L.; Drake, David R.; Dawson, Deborah V.; Blanchette, Derek R.; Brogden, Kim A.

2012-01-01

86

Pharmacodynamics of telavancin (TD-6424), a novel bactericidal agent, against gram-positive bacteria.  

PubMed

Telavancin (TD-6424) is a novel lipoglycopeptide that produces rapid and concentration-dependent killing of clinically relevant gram-positive organisms in vitro. The present studies evaluated the in vivo pharmacodynamics of telavancin in the mouse neutropenic thigh (MNT) and mouse subcutaneous infection (MSI) animal models. Pharmacokinetic-pharmacodynamic studies in the MNT model demonstrated that the 24-h area under the concentration-time curve (AUC)/MIC ratio was the best predictor of efficacy. Telavancin produced dose-dependent reduction of thigh titers of several organisms, including methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA), penicillin-susceptible and -resistant strains of Streptococcus pneumoniae, and vancomycin-resistant Enterococcus faecalis. The 50% effective dose (ED50) estimates for telavancin ranged from 0.5 to 6.6 mg/kg of body weight (administered intravenously), and titers were reduced by up to 3 log10 CFU/g from pretreatment values. Against MRSA ATCC 33591, telavancin was 4- and 30-fold more potent (on an ED50 basis) than vancomycin and linezolid, respectively. Against MSSA ATCC 13709, telavancin was 16- and 40-fold more potent than vancomycin and nafcillin, respectively. Telavancin, vancomycin, and linezolid were all efficacious and more potent against MRSA ATCC 33591 in the MSI model compared to the MNT model. This deviation in potency was, however, disproportionately greater for vancomycin and linezolid than for telavancin, suggesting that activity of telavancin is less affected by the immune status. The findings of these studies collectively suggest that once-daily dosing of telavancin may provide an effective approach for the treatment of clinically relevant infections with gram-positive organisms. PMID:15273119

Hegde, Sharath S; Reyes, Noe; Wiens, Tania; Vanasse, Nicole; Skinner, Robert; McCullough, Julia; Kaniga, Koné; Pace, John; Thomas, Roger; Shaw, Jeng-Pyng; Obedencio, Glen; Judice, J Kevin

2004-08-01

87

Antibacterial activity of oregano (Origanum vulgare Linn.) against gram positive bacteria.  

PubMed

The present investigation is focused on antibacterial potential of infusion, decoction and essential oil of oregano (Origanum vulgare) against 111 Gram-positive bacterial isolates belonging to 23 different species related to 3 genera. Infusion and essential oil exhibited antibacterial activity against Staphylococcus saprophyticus, S. aureus, Micrococcus roseus, M. kristinae, M. nishinomiyaensis, M. lylae, M. luteus, M. sedentarius, M. varians, Bacillus megaterium, B. thuringiensis, B. alvei, B. circulans, B. brevis, B. coagulans, B. pumilus, B. laterosporus, B. polymyxa, B. macerans, B. subtilis, B. firmus, B. cereus and B. lichiniformis. The infusion exhibited maximum activity against B. laterosporus (17.5 mm mean zone of inhibition+/-1.5 Standard deviation) followed by B. polymyxa (17.0 mm+/-2.0 SD) and essential oil of oregano exhibited maximum activity against S. saprophyticus (16.8 mm+/-1.8 SD) followed by B. circulans (14.5 mm+/-0.5 SD). While all these tested isolates were found resistant to decoction of oregano. PMID:19783523

Saeed, Sabahat; Tariq, Perween

2009-10-01

88

Glutathione-independent isomerization of maleylpyruvate by Bacillus megaterium and other gram-positive bacteria.  

PubMed Central

Maleylpyruvate, the ring fission product of gentisic acid, was found to be isomerized to fumarylpyruvate without a requirement for glutathione by an enzyme activity found in cell extracts of m-hydroxybenzoate-grown Bacillus megaterium 410. The isomerization reaction was detected as a shift in the absorbance maximum from 330 nm, the maximum for maleylpyruvate, to 345 nm, the maximum for fumarylpyruvate, when assayed at pH 8.0. Ammonium sulfate precipitation and dialysis of B. megaterium cell extracts resolved the isomerase activity from low-molecular-weight compounds such as glutathione but did not eliminate the isomerase activity. Iodoacetate and p-chloromercuribenzoate were potent inhibitors of the isomerase from B. megaterium. However, N-ethylmaleimide and iodoacetamide did not significantly inhibit this activity. In addition, fumaric acid was demonstrated as a product of gentisate oxidation by dialyzed cell extracts of B. megaterium. Glutathione-independent maleylpyruvate isomerases with properties similar to the isomerase found in B. megaterium were also found in other genera of gram-positive organisms. Eleven different organisms representing the genera Bacillus, Arthrobacter, Corynebacterium, Nocardia, and Rhodococcus were all found to possess this novel type of glutathione-independent maleylpyruvate isomerase. PMID:3926749

Hagedorn, S R; Bradley, G; Chapman, P J

1985-01-01

89

Enhanced antibacterial and anti-biofilm activities of silver nanoparticles against Gram-negative and Gram-positive bacteria  

PubMed Central

Silver nanoparticles (AgNPs) have been used as antibacterial, antifungal, antiviral, anti-inflammtory, and antiangiogenic due to its unique properties such as physical, chemical, and biological properties. The present study was aimed to investigate antibacterial and anti-biofilm activities of silver nanoparticles alone and in combination with conventional antibiotics against various human pathogenic bacteria. Here, we show that a simple, reliable, cost effective and green method for the synthesis of AgNPs by treating silver ions with leaf extract of Allophylus cobbe. The A. cobbe-mediated synthesis of AgNPs (AgNPs) was characterized by ultraviolet-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the antibacterial and anti-biofilm activity of antibiotics or AgNPs, or combinations of AgNPs with an antibiotic was evaluated using a series of assays: such as in vitro killing assay, disc diffusion assay, biofilm inhibition, and reactive oxygen species generation in Pseudomonas aeruginosa, Shigella flexneri, Staphylococcus aureus, and Streptococcus pneumonia. The results suggest that, in combination with antibiotics, there were significant antimicrobial and anti-biofilm effects at lowest concentration of AgNPs using a novel plant extract of A. cobbe, otherwise sublethal concentrations of the antibiotics. The significant enhancing effects were observed for ampicillin and vancomycin against Gram-negative and Gram-positive bacteria, respectively. These data suggest that combining antibiotics and biogenic AgNPs can be used therapeutically for the treatment of infectious diseases caused by bacteria. This study presented evidence of antibacterial and anti-biofilm effects of A. cobbe-mediated synthesis of AgNPs and their enhanced capacity against various human pathogenic bacteria. These results suggest that AgNPs could be used as an adjuvant for the treatment of infectious diseases. PMID:25136281

2014-01-01

90

Enhanced antibacterial and anti-biofilm activities of silver nanoparticles against Gram-negative and Gram-positive bacteria  

NASA Astrophysics Data System (ADS)

Silver nanoparticles (AgNPs) have been used as antibacterial, antifungal, antiviral, anti-inflammtory, and antiangiogenic due to its unique properties such as physical, chemical, and biological properties. The present study was aimed to investigate antibacterial and anti-biofilm activities of silver nanoparticles alone and in combination with conventional antibiotics against various human pathogenic bacteria. Here, we show that a simple, reliable, cost effective and green method for the synthesis of AgNPs by treating silver ions with leaf extract of Allophylus cobbe. The A. cobbe-mediated synthesis of AgNPs (AgNPs) was characterized by ultraviolet-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the antibacterial and anti-biofilm activity of antibiotics or AgNPs, or combinations of AgNPs with an antibiotic was evaluated using a series of assays: such as in vitro killing assay, disc diffusion assay, biofilm inhibition, and reactive oxygen species generation in Pseudomonas aeruginosa, Shigella flexneri, Staphylococcus aureus, and Streptococcus pneumonia. The results suggest that, in combination with antibiotics, there were significant antimicrobial and anti-biofilm effects at lowest concentration of AgNPs using a novel plant extract of A. cobbe, otherwise sublethal concentrations of the antibiotics. The significant enhancing effects were observed for ampicillin and vancomycin against Gram-negative and Gram-positive bacteria, respectively. These data suggest that combining antibiotics and biogenic AgNPs can be used therapeutically for the treatment of infectious diseases caused by bacteria. This study presented evidence of antibacterial and anti-biofilm effects of A. cobbe-mediated synthesis of AgNPs and their enhanced capacity against various human pathogenic bacteria. These results suggest that AgNPs could be used as an adjuvant for the treatment of infectious diseases.

Gurunathan, Sangiliyandi; Han, Jae Woong; Kwon, Deug-Nam; Kim, Jin-Hoi

2014-07-01

91

Cerium oxide and iron oxide nanoparticles abolish the antibacterial activity of ciprofloxacin against gram positive and gram negative biofilm bacteria.  

PubMed

Metal oxide nanoparticles have been suggested as good candidates for the development of antibacterial agents. Cerium oxide (CeO2) and iron oxide (Fe2O3) nanoparticles have been utilized in a number of biomedical applications. Here, the antibacterial activity of CeO2 and Fe2O3 nanoparticles were evaluated on a panel of gram positive and gram negative bacteria in both the planktonic and biofilm cultures. Additionally, the effect of combining CeO2 and Fe2O3 nanoparticles with the broad spectrum antibiotic ciprofloxacin on tested bacteria was investigated. Thus, minimum inhibitory concentrations (MICs) of CeO2 and Fe2O3 nanoparticles that are required to inhibit bacterial planktonic growth and bacterial biofilm, were evaluated, and were compared to the MICs of the broad spectrum antibiotic ciprofloxacin alone or in the presence of CeO2 and Fe2O3 nanoparticles. Results of this study show that both CeO2 and Fe2O3 nanoparticles fail to inhibit bacterial growth and biofilm biomass for all the bacterial strains tested. Moreover, adding CeO2 or Fe2O3 nanoparticles to the broad spectrum antibiotic ciprofloxacin almost abolished its antibacterial activity. Results of this study suggest that CeO2 and Fe2O3 nanoparticles are not good candidates as antibacterial agents, and they could interfere with the activity of important antibiotics. PMID:24643389

Masadeh, Majed M; Karasneh, Ghadah A; Al-Akhras, Mohammad A; Albiss, Borhan A; Aljarah, Khaled M; Al-Azzam, Sayer I; Alzoubi, Karem H

2015-05-01

92

Mobilizable Rolling-Circle Replicating Plasmids from Gram-Positive Bacteria: A Low-Cost Conjugative Transfer  

PubMed Central

Chapter summary Conjugation is a key mechanism for horizontal gene transfer in bacteria. Some plasmids are not self-transmissible but can be mobilized by functions encoded in trans provided by other auxiliary conjugative elements. Although the transfer efficiency of mobilizable plasmids is usually lower than that of conjugative elements, mobilizable plasmidsare more frequently found in nature. In this sense, replication and mobilization can be considered as important mechanisms influencing plasmid promiscuity. Here we review the present available information on two families of small mobilizable plasmids from Gram-positive bacteria that replicate via the rolling-circle mechanism. One of these families, represented by the streptococcal plasmid pMV158, is an interesting model since it contains a specific mobilization module (MOBV) that is widely distributed among mobilizable plasmids. We discuss a mechanism in which the promiscuity of the pMV158 replicon is based on the presence of two origins of lagging strand synthesis. The current strategies to assess plasmid transfer efficiency as well as to inhibit conjugative plasmid transfer are presented. Some applications of these plasmids as biotechnological tools are also reviewed. PMID:25606350

Fernández-López, Cris; Bravo, Alicia; Ruiz-Cruz, Sofía; Solano-Collado, Virtu; Garsin, Danielle A.; Lorenzo-Díaz, Fabián; Espinosa, Manuel

2014-01-01

93

Genome-wide gene order distances support clustering the gram-positive bacteria  

PubMed Central

Initially using 143 genomes, we developed a method for calculating the pair-wise distance between prokaryotic genomes using a Monte Carlo method to estimate the conservation of gene order. The method was based on repeatedly selecting five or six non-adjacent random orthologs from each of two genomes and determining if the chosen orthologs were in the same order. The raw distances were then corrected for gene order convergence using an adaptation of the Jukes-Cantor model, as well as using the common distance correction D? = ?ln(1-D). First, we compared the distances found via the order of six orthologs to distances found based on ortholog gene content and small subunit rRNA sequences. The Jukes-Cantor gene order distances are reasonably well correlated with the divergence of rRNA (R2 = 0.24), especially at rRNA Jukes-Cantor distances of less than 0.2 (R2 = 0.52). Gene content is only weakly correlated with rRNA divergence (R2 = 0.04) over all distances, however, it is especially strongly correlated at rRNA Jukes-Cantor distances of less than 0.1 (R2 = 0.67). This initial work suggests that gene order may be useful in conjunction with other methods to help understand the relatedness of genomes. Using the gene order distances in 143 genomes, the relations of prokaryotes were studied using neighbor joining and agreement subtrees. We then repeated our study of the relations of prokaryotes using gene order in 172 complete genomes better representing a wider-diversity of prokaryotes. Consistently, our trees show the Actinobacteria as a sister group to the bulk of the Firmicutes. In fact, the robustness of gene order support was found to be considerably greater for uniting these two phyla than for uniting any of the proteobacterial classes together. The results are supportive of the idea that Actinobacteria and Firmicutes are closely related, which in turn implies a single origin for the gram-positive cell. PMID:25653643

House, Christopher H.; Pellegrini, Matteo; Fitz-Gibbon, Sorel T.

2015-01-01

94

The effect of Indomethacin and Betamethasone on the cytokine response of human neonatal mononuclear cells to gram-positive bacteria.  

PubMed

Intrauterine infections with gram-positive bacteria pose a serious threat to neonates since they can result in neonatal sepsis, induce a fetal inflammatory response and also cause preterm birth. Despite intensive care, prematurity remains a leading cause of neonatal death, and is often accompanied by a number of morbidities. In order to prevent premature birth, tocolytic agents like Indomethacin are administered. Betamethasone is used to promote lung maturation and prevent respiratory distress syndrome. A combination of both drugs is assumed to prevent premature delivery while simultaneously facilitating lung maturation. This study investigates the effect of Betamethasone, Indomethacin and a combination of both on the cytokine production of neonatal cord blood mononuclear cells (CBMC) after stimulation with lysates of the gram-positive pathogens Streptococcus agalactiae and Enterococcus faecalis. The aim of the study is to determine the impact of these drugs on the function of the neonatal immune system which should aid clinicians in choosing the optimal therapy in case of preterm birth associated with intrauterine infection. Betamethasone reduced the production of the pro-inflammatory cytokines IL-6, IL-12p40, MIP-1? and TNF and increased the expression of the anti-inflammatory cytokine IL-10, depending on the pathogen used for stimulation. In contrast to Betamethasone, Indomethacin almost exclusively increased IL-10 production. The combination of both drugs decreased the expression of IL-6, IL-12p40, MIP-1? and TNF while increasing IL-10 production, depending on the concentration of Indomethacin and the pathogen used for stimulation. Based on our results, the combination therapy with Indomethacin and Betamethasone has a similar effect on cytokine production as Betamethasone alone, which is generally administered in case of impending preterm birth. However, the combination therapy has the advantage of promoting lung maturation while simultaneously blocking preterm labor effectively. PMID:25743243

Ernst, Wolfgang; Kusi, Evelyn; Fill Malfertheiner, Sara; Reuschel, Edith; Deml, Ludwig; Seelbach-Göbel, Birgit

2015-05-01

95

Specific Inhibitors of Bacterial Adhesion: Observations From the Study of Gram-Positive Bacteria that Initiate Biofilm Formation on the Tooth Surface  

Microsoft Academic Search

Oral surfaces are bathed in secretory antibodies and other salivary macromolecules that are potential inhibitors of specific microbial adhesion. Indigenous Gram-positive bacteria that colonize teeth, including viridans streptococci and actinomyces, may avoid inhibition of adhesion by host secretory molecules through various strategies that involve the structural design and binding properties of bacterial adhesins and receptors. Further studies to define the

J. O. Cisar; Y. Takahashi; S. Ruhl; J. A. Donkersloot; A. L. Sandberg

1997-01-01

96

Novel bacterial lipoprotein structures conserved in low-GC content gram-positive bacteria are recognized by Toll-like receptor 2.  

PubMed

Bacterial lipoproteins/lipopeptides inducing host innate immune responses are sensed by mammalian Toll-like receptor 2 (TLR2). These bacterial lipoproteins are structurally divided into two groups, diacylated or triacylated lipoproteins, by the absence or presence of an amide-linked fatty acid. The presence of diacylated lipoproteins has been predicted in low-GC content gram-positive bacteria and mycoplasmas based on the absence of one modification enzyme in their genomes; however, we recently determined triacylated structures in low-GC gram-positive Staphylococcus aureus, raising questions about the actual lipoprotein structure in other low-GC content gram-positive bacteria. Here, through intensive MS analyses, we identified a novel and unique bacterial lipoprotein structure containing an N-acyl-S-monoacyl-glyceryl-cysteine (named the lyso structure) from low-GC gram-positive Enterococcus faecalis, Bacillus cereus, Streptococcus sanguinis, and Lactobacillus bulgaricus. Two of the purified native lyso-form lipoproteins induced proinflammatory cytokine production from mice macrophages in a TLR2-dependent and TLR1-independent manner but with a different dependence on TLR6. Additionally, two other new lipoprotein structures were identified. One is the "N-acetyl" lipoprotein structure containing N-acetyl-S-diacyl-glyceryl-cysteine, which was found in five gram-positive bacteria, including Bacillus subtilis. The N-acetyl lipoproteins induced the proinflammatory cytokines through the TLR2/6 heterodimer. The other was identified in a mycoplasma strain and is an unusual diacyl lipoprotein structure containing two amino acids before the lipid-modified cysteine residue. Taken together, our results suggest the existence of novel TLR2-stimulating lyso and N-acetyl forms of lipoproteins that are conserved in low-GC content gram-positive bacteria and provide clear evidence for the presence of yet to be identified key enzymes involved in the bacterial lipoprotein biosynthesis. PMID:22303020

Kurokawa, Kenji; Ryu, Kyoung-Hwa; Ichikawa, Rie; Masuda, Akiko; Kim, Min-Su; Lee, Hanna; Chae, Jun-Ho; Shimizu, Takashi; Saitoh, Tatsuya; Kuwano, Koichi; Akira, Shizuo; Dohmae, Naoshi; Nakayama, Hiroshi; Lee, Bok Luel

2012-04-13

97

Gram-Positive Nickel Resistant Bacteria Isolated from Riparian Sediments Contaminated with Ni and U on the Savannah River Site  

NASA Astrophysics Data System (ADS)

The natural attenuation of pollutants in riparian and wetland systems is driven in large part by the services provided by the diverse microbial communities that thrive in these nutritionally and chemically complex environments. For co-contaminated systems, the presence of heavy metals at excessive levels may alter the structure and function of microbial communities that are essential for the immobilization of inorganics and degradation of organic contaminants. We examined riparian sediments heavily contaminated with U and Ni (1000's of mg/kg) from a small stream on the U.S. Department of Energy's Savannah River Site that received metallurgical process effluents wastewater over a thirty-year period associated with the production of nuclear materials. Four gram positive bacteria were isolated that displayed marked resistance (5000 mg/kg) to Ni relative to organisms from uncontaminated control locations: Arthrobacter oxydans, Streptomyces galbus, Streptomyces aureofaciens, and Kitasatospora cystarginea. The metal resistance of S. aureofaciens and K. cystarginea was further characterized in growth experiments for resistance to other metals. Ongoing geochemical characterization of U and Ni in terms of solid phase partitioning and aqueous phase speciation and solubility indicate that Ni is more chemically labile and, by extension, bioavailable than U in these aged-contaminated sediments. Accordingly, the isolation of Ni resistant organisms is consistent with greater selective pressure from Ni as a result of its greater bioavailability. These results are placed in context of environmental management and remediation of co-contaminated, biogeochemically complex environments.

Sowder, A. G.; Khijniak, T. V.; van Nostrand, J.; Bertsch, P. M.; Morris, P. J.

2002-12-01

98

Quantification of Gram-positive bacteria: adaptation and evaluation of a preparation strategy using high amounts of clinical tissue  

PubMed Central

Background A preparation method for quantification of bacteria in tissues is obligatory to reduce tissue mass, concentrate the target, purify, remove inhibitory substances and to achieve constant target recovery rates. No preparation method has been available until now for a high mass of tissue applicable for routine use and analytical veterinary diagnostics. Results This study describes an easy-to-use tissue preparation protocol to quantify Gram-positive bacteria from a large volume of tissue matrix. A previously published sample preparation method (Matrix-Lysis) from food science was successfully adapted for clinical use on tissues from pigs, including cerebrum, spinal cord, lung, liver, ileum, colon, caecum, kidney and muscle tissue. This tissue preparation method now permits quantification of pathogens from 5 g of organic matrix, which is a 20–200 fold increase by weight compared to other methods. It is based on solubilization of the sample matrix with either a chaotrope plus detergent or divalent salts as solubilization agents. The method was designed as a modular system, offering the possibility to change lysis buffers, according to tissue solubilization characteristics and the intended detection method (molecular or culture). Using Listeria monocytogenes as model organism, viable cell quantification or DNA extraction and quantitative real-time PCR were performed after Matrix-Lysis to determine recovery rates and detection limit (LOD). The adapted Matrix-Lysis protocol resulted in high recovery rates (mean value: 76%?±?39%) for all tested organs, except kidney, and recovery was constant over 5 log scales for all tested buffer systems. The LOD for Matrix-Lysis with subsequent plate count method (PCM) was as low as 1 CFU/5 g, while for qPCR based detection the LOD was 102 bacterial cell equivalents (BCE)/5 g for two buffer systems. Conclusions This tissue preparation is inexpensive and can be easily used for routine and analytical veterinary diagnostics. Inoculation studies or hazard assessments can profit from this tissue preparation method and it is anticipated that this study will be a valuable source for further research on tissue preparation strategies. PMID:24589061

2014-01-01

99

Expanding the Use of a Fluorogenic Method to Determine Activity and Mode of Action of Bacillus thuringiensis Bacteriocins Against Gram-Positive and Gram-Negative Bacteria  

PubMed Central

Previously we described a rapid fluorogenic method to measure the activity of five bacteriocins produced by Mexican strains of Bacillus thuringiensis against B. cereus 183. Here we standardize this method to efficiently determine the activity of bacteriocins against both Gram-positive and Gram-negative bacteria. It was determined that the crucial parameter required to obtain reproducible results was the number of cells used in the assay, that is, ~4?×?108?cell/mL and ~7?×?108?cell/mL, respectively, for target Gram-positive and Gram-negative bacteria. Comparative analyses of the fluorogenic and traditional well-diffusion assays showed correlation coefficients of 0.88 to 0.99 and 0.83 to 0.99, respectively, for Gram-positive and Gram-negative bacteria. The fluorogenic method demonstrated that the five bacteriocins of B. thuringiensis have bacteriolytic and bacteriostatic activities against all microorganisms tested, including clinically significant bacteria such as Listeria monocytogenes, Proteus vulgaris, and Shigella flexneri reported previously to be resistant to the antimicrobials as determined using the well-diffusion protocol. These results demonstrate that the fluorogenic assay is a more sensitive, reliable, and rapid method when compared with the well-diffusion method and can easily be adapted in screening protocols for bacteriocin production by other microorganisms. PMID:22919330

de la Fuente-Salcido, Norma M.; Barboza-Corona, J. Eleazar; Espino Monzón, A. N.; Pacheco Cano, R. D.; Balagurusamy, N.; Bideshi, Dennis K.; Salcedo-Hernández, Rubén

2012-01-01

100

Selective growth promotion and growth inhibition of Gram-negative and Gram-positive bacteria by synthetic siderophore-?-lactam conjugates  

Microsoft Academic Search

Conjugates of a carbacephalosporin with hydroxamate, spermexatol, N,N-bis(2,3-dihydroxybenzoyl)-L-lysine, mixed catecholate\\/hydroxamate and cyanuric acid-based siderophores were investigated for their potential to promote growth of siderophore indicator strains of Gram-negative and Gram-positive bacteria under iron depleted conditions, for their antibacterial activity and for their ability to use iron transport path-ways to penetrate the Gram-negative bacterial outer membrane. The selective growth promotion of

Ute Möllmann; Arun Ghosh; Eric K. Dolence; Julia A. Dolence; Manuka Ghosh; Marvin J. Miller; R. Reissbrodt

1998-01-01

101

Phylogenetic Placement of Dialister pneumosintes (formerly Bacteroides pneumosintes) within the Sporomusa Subbranch of the Clostridium Subphylum of the Gram-Positive Bacteria  

Microsoft Academic Search

The nucleotide sequence of the 16s rRNA gene of the type strain of Dialisfer pneumosinfes was determined. Phylogenetic analysis revealed that this species belongs to the Sporomusa branch of the Clostridum subphylum of the gram-positive bacteria and should therefore be excluded from the family Bacferoidaceae. Within this branch, which encompasses several other gram-negative taxa, such as Acidarninococcus, Pectinatus, Phascolar- cobacferium,

ANNE WILLEMS; MATTHEW D. COLLINS

1995-01-01

102

Lactobacillus plantarum gene clusters encoding putative cell-surface protein complexes for carbohydrate utilization are conserved in specific gram-positive bacteria  

Microsoft Academic Search

BACKGROUND: Genomes of gram-positive bacteria encode many putative cell-surface proteins, of which the majority has no known function. From the rapidly increasing number of available genome sequences it has become apparent that many cell-surface proteins are conserved, and frequently encoded in gene clusters or operons, suggesting common functions, and interactions of multiple components. RESULTS: A novel gene cluster encoding exclusively

Roland Siezen; Jos Boekhorst; Lidia Muscariello; Douwe Molenaar; Bernadet Renckens; Michiel Kleerebezem

2006-01-01

103

In situ probing of Gram-positive bacteria with high DNA G + C content using 23S rRNA-targeted oligonucleotides  

Microsoft Academic Search

235-rRNA-targeted oligonucleotide probes were designed for the phylogenetic group Gram-positive bacteria with high G + C content of DNA ' (GPBHGC). A sequence idiosyncrasy in two adjacent base pairs in the stem of helix 69 in domain IV of the 235 rRNA is present in all hitherto analysed strains of GPBHGC. An oligonucleotide probe targeted to this region hybridized only

Carsten Roller; Michael Wagner; Rudolf Amann; Wolfgang Ludwig; K.-H. Schleifer

1994-01-01

104

Multiplex Identification of Gram-Positive Bacteria and Resistance Determinants Directly from Positive Blood Culture Broths: Evaluation of an Automated Microarray-Based Nucleic Acid Test  

PubMed Central

Background A multicenter study was conducted to evaluate the diagnostic accuracy (sensitivity and specificity) of the Verigene Gram-Positive Blood Culture Test (BC-GP) test to identify 12 Gram-positive bacterial gene targets and three genetic resistance determinants directly from positive blood culture broths containing Gram-positive bacteria. Methods and Findings 1,252 blood cultures containing Gram-positive bacteria were prospectively collected and tested at five clinical centers between April, 2011 and January, 2012. An additional 387 contrived blood cultures containing uncommon targets (e.g., Listeria spp., S. lugdunensis, vanB-positive Enterococci) were included to fully evaluate the performance of the BC-GP test. Sensitivity and specificity for the 12 specific genus or species targets identified by the BC-GP test ranged from 92.6%–100% and 95.4%–100%, respectively. Identification of the mecA gene in 599 cultures containing S. aureus or S. epidermidis was 98.6% sensitive and 94.3% specific compared to cefoxitin disk method. Identification of the vanA gene in 81 cultures containing Enterococcus faecium or E. faecalis was 100% sensitive and specific. Approximately 7.5% (87/1,157) of single-organism cultures contained Gram-positive bacteria not present on the BC-GP test panel. In 95 cultures containing multiple organisms the BC-GP test was in 71.6% (68/95) agreement with culture results. Retrospective analysis of 107 separate blood cultures demonstrated that identification of methicillin resistant S. aureus and vancomycin resistant Enterococcus spp. was completed an average of 41.8 to 42.4 h earlier using the BC-GP test compared to routine culture methods. The BC-GP test was unable to assign mecA to a specific organism in cultures containing more than one Staphylococcus isolate and does not identify common blood culture contaminants such as Micrococcus, Corynebacterium, and Bacillus. Conclusions The BC-GP test is a multiplex test capable of detecting most leading causes of Gram-positive bacterial blood stream infections as well as genetic markers of methicillin and vancomycin resistance directly from positive blood cultures. Please see later in the article for the Editors' Summary PMID:23843749

Buchan, Blake W.; Ginocchio, Christine C.; Manii, Ryhana; Cavagnolo, Robert; Pancholi, Preeti; Swyers, Lettie; Thomson, Richard B.; Anderson, Christopher; Kaul, Karen; Ledeboer, Nathan A.

2013-01-01

105

Alternating electric fields combined with activated carbon for disinfection of Gram negative and Gram positive bacteria in fluidized bed electrode system.  

PubMed

Strong electric fields for disinfection of wastewaters have been employed already for several decades. An innovative approach combining low strength (7 V/cm) alternating electric fields with a granular activated carbon fluidized bed electrode (FBE) for disinfection was presented recently. For disinfection performance of FBE several pure microbial cultures were tested: Bacillus subtilis, Bacillus subtilis subsp. subtilis, Enterococcus faecalis as representatives from Gram positive bacteria and Erwinia carotovora, Pseudomonas luteola, Pseudomonas fluorescens and Escherichia coli YMc10 as representatives from Gram negative bacteria. The alternating electric field amplitude and shape were kept constant. Only the effect of alternating electric field frequency on disinfection performance was investigated. From the bacteria tested, the Gram negative strains were more susceptible and the Gram positive microorganisms were more resistant to FBE disinfection. The collected data indicate that the efficiency of disinfection is frequency and strain dependent. During 6 h of disinfection, the decrease above 2 Log units was achieved with P. luteola and E. coli at 10 kHz and at dual frequency shift keying (FSK) modulated signal with frequencies of 10 kHz and 140 kHz. FBE technology appears to offer a new way for selective bacterial disinfection, however further optimizations are needed on treatment duration, and energy input, to improve effectiveness. PMID:24012021

Racyte, Justina; Bernard, Séverine; Paulitsch-Fuchs, Astrid H; Yntema, Doekle R; Bruning, Harry; Rijnaarts, Huub H M

2013-10-15

106

Potentiation of photoinactivation of Gram-positive and Gram-negative bacteria mediated by six phenothiazinium dyes by addition of azide ion.  

PubMed

Antimicrobial photodynamic inactivation (APDI) using phenothiazinium dyes is mediated by reactive oxygen species consisting of a combination of singlet oxygen (quenched by azide), hydroxyl radicals and other reactive oxygen species. We recently showed that addition of sodium azide paradoxically potentiated APDI of Gram-positive and Gram-negative bacteria using methylene blue as the photosensitizer, and this was due to electron transfer to the dye triplet state from azide anion, producing azidyl radical. Here we compare this effect using six different homologous phenothiazinium dyes: methylene blue, toluidine blue O, new methylene blue, dimethylmethylene blue, azure A, and azure B. We found both significant potentiation (up to 2 logs) and also significant inhibition (>3 logs) of killing by adding 10 mM azide depending on Gram classification, washing the dye from the cells, and dye structure. Killing of E. coli was potentiated with all 6 dyes after a wash, while S. aureus killing was only potentiated by MB and TBO with a wash and DMMB with no wash. More lipophilic dyes (higher log P value, such as DMMB) were more likely to show potentiation. We conclude that the Type I photochemical mechanism (potentiation with azide) likely depends on the microenvironment, i.e. higher binding of dye to bacteria. Bacterial dye-binding is thought to be higher with Gram-negative compared to Gram-positive bacteria, when unbound dye has been washed away, and with more lipophilic dyes. PMID:25177833

Kasimova, Kamola R; Sadasivam, Magesh; Landi, Giacomo; Sarna, Tadeusz; Hamblin, Michael R

2014-11-01

107

Systematic Review of Membrane Components of Gram-Positive Bacteria Responsible as Pyrogens for Inducing Human Monocyte/Macrophage Cytokine Release  

PubMed Central

Fifty years after the elucidation of lipopolysaccharides (LPS, endotoxin) as the principal structure of Gram-negative bacteria activating the human immune system, its Gram-positive counterpart is still under debate. Pyrogen tests based on the human monocyte activation have been validated for LPS detection as an alternative to the rabbit test and, increasingly, the limulus amebocyte lysate test. For full replacement, international validations with non-endotoxin pyrogens are in preparation. Following evidence-based medicine approaches, a systematic review of existing evidence as to the structural nature of the Gram-positive pyrogen was undertaken. For the three major constituents suggested, i.e., peptidoglycan, lipoteichoic acids (LTA), and bacterial lipoproteins (LP), the questions to be answered and a search strategy for relevant literature was developed, starting in MedLine. The evaluation was based on the Koch–Dale criteria for a mediator of an effect. A total of 380 articles for peptidoglycan, 391 for LP, and 285 for LTA were retrieved of which 12, 8, and 24, respectively, fulfilled inclusion criteria. The compiled data suggest that for peptidoglycan two Koch–Dale criteria are fulfilled, four for LTA, and two for bacterial LP. In conclusion, based on the best currently available evidence, LTA is the only substance that fulfills all criteria. LTA has been isolated from a large number of bacteria, results in cytokine release patterns inducible also with synthetic LTA. Reduction in bacterial cytokine induction with an inhibitor for LTA was shown. However, this systematic review cannot exclude the possibility that other stimulatory compounds complement or substitute for LTA in being the counterpart to LPS in some Gram-positive bacteria. PMID:22529809

Rockel, Christoph; Hartung, Thomas

2012-01-01

108

Disinfection of gram-negative and gram-positive bacteria using D ynaJ ets® hydrodynamic cavitating jets  

Microsoft Academic Search

Cavitating jet technologies (DynaJets®) were investigated as a means of disinfection of gram-negative Escherichia coli, Klebsiellapneumoniae, Pseudomonas syringae, and Pseudomonas aeruginosa, and gram-positive Bacillus subtilis. The hydrodynamic cavitating jets were found to be very effective in reducing the concentrations of all of these species. In general, the observed rates of disinfection of gram-negative species were higher than for gram-positive species.

Gregory Loraine; Georges Chahine; Chao-Tsung Hsiao; Jin-Keun Choi; Patrick Aley

109

Physico-Chemical-Managed Killing of Penicillin-Resistant Static and Growing Gram-Positive and Gram-Negative Vegetative Bacteria  

NASA Technical Reports Server (NTRS)

Systems and methods for the use of compounds from the Hofmeister series coupled with specific pH and temperature to provide rapid physico-chemical-managed killing of penicillin-resistant static and growing Gram-positive and Gram-negative vegetative bacteria. The systems and methods represent the more general physico-chemical enhancement of susceptibility for a wide range of pathological macromolecular targets to clinical management by establishing the reactivity of those targets to topically applied drugs or anti-toxins.

Richmond, Robert Chaffee (Inventor); Schramm, Jr., Harry F. (Inventor); Defalco, Francis G. (Inventor); Farris, III, Alex F. (Inventor)

2012-01-01

110

Antimicrobial and Efflux Pump Inhibitory Activity of Caffeoylquinic Acids from Artemisia absinthium against Gram-Positive Pathogenic Bacteria  

Microsoft Academic Search

Background: Traditional antibiotics are increasingly suffering from the emergence of multidrug resistance amongst pathogenic bacteria leading to a range of novel approaches to control microbial infections being investigated as potential alternative treatments. One plausible antimicrobial alternative could be the combination of conventional antimicrobial agents\\/antibiotics with small molecules which block multidrug efflux systems known as efflux pump inhibitors. Bioassay- driven purification

Yiannis C. Fiamegos; Panagiotis L. Kastritis; Vassiliki Exarchou; Haley Han; Alexandre M. J. J. Bonvin; Jacques Vervoort; Kim Lewis; Michael R. Hamblin; George P. Tegos

2011-01-01

111

Homologous gene clusters of nicotine catabolism, including a new ?-amidase for ?-ketoglutaramate, in species of three genera of Gram-positive bacteria.  

PubMed

Gram-positive soil bacteria Arthrobacter nicotinovorans, Nocardioides sp. JS614 and Rhodococcus opacus were shown to contain similarly organized clusters of homologous genes for nicotine catabolism. An uncharacterized gene of a predicted nitrilase within these gene clusters was cloned from A. nicotinovorans and biochemical data unexpectedly showed that the protein exhibited ?-amidase activity toward ?-ketoglutaramate. Structural modelling of the protein suggested the presence of the catalytic triad Cys-Glu-Lys, characteristic of this class of enzymes, and supported ?-ketoglutaramate as substrate. A-ketoglutaramate could be generated by hydrolytic cleavage of the C-N bond of the trihydroxypyridine ring produced by nicotine catabolism in these bacteria. This ?-amidase, together with glutamate dehydrogenase, may form a physiologically relevant enzyme couple, leading to transformation of metabolically inert ?-ketoglutaramate derived from trihydroxypyridine into glutamate, a central compound of nitrogen metabolism. PMID:21288482

Cobzaru, Cristina; Ganas, Petra; Mihasan, Marius; Schleberger, Paula; Brandsch, Roderich

2011-04-01

112

Comparison of killing of gram-negative and gram-positive bacteria by pure singlet oxygen. [Salmonella typhimurium; Escherichia coli; Sarcina lutea; Staphylococcus aureus; Streptococcus lactis; Streptococcus faecalis  

SciTech Connect

Gram-negative and gram-positive bacteria were found to display different sensitivities to pure singlet oxygen generated outside of cells. Killing curves for Salmonella typhimurium and Escherichia coli strains were indicative of multihit killing, whereas curves for Sarcina lutea, Staphylococcus aureus, Streptococcus lactis, and Streptococcus faecalis exhibited single-hit kinetics. The S. typhimurium deep rough strain TA1975, which lacks nearly all of the cell wall lipopolysaccharide coat and manifests concomitant enhancement of penetration by some exogenous substances, responded to singlet oxygen with initially faster inactivation than did the S. typhimurium wild-type strain, although the maximum rates of killing appeared to be quite similar. The structure of the cell wall thus plays an important role in susceptibility to singlet oxygen. The outer membrane-lipopolysaccharide portion of the gram-negative cell wall initially protects the bacteria from extracellular singlet oxygen, although it may also serve as a source for secondary reaction products which accentuate the rates of cell killing. S. typhimurium and E. coli strains lacking the cellular antioxidant, glutathione, showed no difference from strains containing glutathione in response to the toxic effects of singlet oxygen. Strains of Sarcina lutea and Staphylococcus aureus that contained carotenoids, however, were far more resistant to singlet oxygen lethality than were both carotenoidless mutants of the same species and other gram-positive species lacking high levels of protective carotenoids.

Dahl, T.A.; Midden, W.R. (Bowling Green State Univ., OH (USA)); Hartman, P.E. (Johns Hopkins Univ., Baltimore, MD (USA))

1989-04-01

113

Studies on the O3-initiated disinfection from Gram-positive bacteria Bacillus subtilis in aquatic systems  

Microsoft Academic Search

The kinetics of inactivation of Gram-positive strain, Bacillus subtilis in aquatic systems was investigated as function ozone aeration duration under varied conditions. Oxygen flow was in situ enriched with ozone using ozoniser, with [O3] ranging from (0.3 – 9.8) × 10 moles per liter of oxygen. The inactivation kinetics of B. subtilis followed pseudo–first-order kinetics with respect to microbe, under

Favourite N. Zuma; S. B. Jonnalagadda

2010-01-01

114

Acylation of SC4 dodecapeptide increases bactericidal potency against Gram-positive bacteria, including drug-resistant strains  

Microsoft Academic Search

We have conjugated dodecyl and octadecyl fatty acids to the N-terminus of SC4, a potently bactericidal, helix-forming peptide 12-mer (KLFKRHLKWKII), and examined the bactericidal acti- vities of the resultant SC4 'peptide-amphiphile' molecules. SC4 peptide-amphiphiles showed up to a 30-fold increase in bacter- icidal activity against Gram-positive strains (Staphylococcus aureus, Streptococcus pyogenes and Bacillus anthracis), inclu- ding S. aureus strains resistant

2004-01-01

115

A Toll-Like Receptor 2Responsive Lipid Effector Pathway Protects Mammals against Skin Infections with Gram-Positive Bacteria  

Microsoft Academic Search

flake (flk), an N-ethyl-N-nitrosourea-induced recessive germ line mutation of C57BL\\/6 mice, impairs the clearance of skin infections by Streptococcus pyogenes and Staphylococcus aureus, gram-positive pathogens that elicit innate immune responses by activating Toll-like receptor 2 (TLR2) (K. Takeda and S. Akira, Cell. Microbiol. 5:143-153, 2003). Positional cloning and sequencing revealed that flk is a novel allele of the stearoyl coenzyme

Philippe Georgel; Karine Crozat; Xavier Lauth; Evgenia Makrantonaki; Holger Seltmann; Sosathya Sovath; Kasper Hoebe; Xin Du; Sophie Rutschmann; Zhengfan Jiang; Timothy Bigby; Victor Nizet; Christos C. Zouboulis; Bruce Beutler

2005-01-01

116

Lysis of gram-positive and gram-negative bacteria by antibacterial porous polymeric monolith formed in microfluidic biochips for sample preparation.  

PubMed

Bacterial cell lysis is demonstrated using polymeric microfluidic biochips operating via a hybrid mechanical shearing/contact killing mechanism. These biochips are fabricated from a cross-linked poly(methyl methacrylate) (X-PMMA) substrate by well-controlled, high-throughput laser micromachining. The unreacted double bonds at the surface of X-PMMA provide covalent bonding for the formation of a porous polymeric monolith (PPM), thus contributing to the mechanical stability of the biochip and eliminating the need for surface treatment. The lysis efficiency of these biochips was tested for gram-positive (Enterococcus saccharolyticus and Bacillus subtilis) and gram-negative bacteria (Escherichia coli and Pseudomonas fluorescens) and confirmed by off-chip PCR without further purification. The influence of the flow rate when pumping the bacterial suspension through the PPM, and of the hydrophobic-hydrophilic balance on the cell lysis efficiency was investigated at a cell concentration of 10(5) CFU/mL. It was shown that the contribution of contact killing to cell lysis was more important than that of mechanical shearing in the PPM. The biochip showed better lysis efficiency than the off-chip chemical, mechanical, and thermal lysis techniques used in this work. The biochip also acts as a filter that isolates cell debris and allows PCR-amplifiable DNA to pass through. The system performs more efficient lysis for gram-negative than for gram-positive bacteria. The biochip does not require chemical/enzymatic reagents, power consumption, or complicated design and fabrication processes, which makes it an attractive on-chip lysis device that can be used in sample preparation for genetics and point-of-care diagnostics. The biochips were reused for 20 lysis cycles without any evidence of physical damage to the PPM, significant performance degradation, or DNA carryover when they were back-flushed between cycles. The biochips efficiently lysed both gram-positive and gram-negative bacteria in about 35 min per lysis and PPM regeneration cycle. PMID:25059724

Aly, Mohamed Aly Saad; Gauthier, Mario; Yeow, John

2014-09-01

117

Antimicrobial Effect of the Triterpene 3?,6?,16?-Trihydroxylup-20(29)-ene on Planktonic Cells and Biofilms from Gram Positive and Gram Negative Bacteria  

PubMed Central

This study evaluated the antimicrobial effect of 3?,6?,16?-trihydroxylup-20(29)-ene (CLF1), a triterpene isolated from Combretum leprosum Mart., in inhibiting the planktonic growth and biofilms of Gram positive bacteria Streptococcus mutans and S. mitis. The antimicrobial activity was assessed by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The antibiofilm potential was determined by quantifying total biomass and enumerating biofilm-entrapped viable bacteria. In addition, the acute toxicity of CLF1 on Artemia sp. nauplii was also determined. The results showed that CLF1 was able in inhibiting the growth of S. mutans and S. mitis with MIC and MBC of 7.8??g/mL and 15.6??g/mL, respectively. CLF1 was highly effective on biofilms of both bacteria. Only 7.8??g/mL CLF1 was enough to inhibit by 97% and 90% biomass production of S. mutans and S. mitis, respectively. On the other hand, such effects were not evident on Gram negative Pseudomonas aeruginosa and Klebsiella oxytoca. The toxicity tests showed that the LC50 of CLF1 was 98.19??g/mL. Therefore, CLF1 isolated from C. leprosum may constitute an important natural agent for the development of new therapies for caries and other infectious diseases caused by S. mutans and S. mitis. PMID:25093179

Evaristo, Francisco Flávio Vasconcelos; Albuquerque, Maria Rose Jane R.; dos Santos, Hélcio Silva; Bandeira, Paulo Nogueira; Ávila, Fábio do Nascimento; da Silva, Bruno Rocha; Vasconcelos, Ariana Azevedo; Rabelo, Érica de Menezes; Nascimento-Neto, Luiz Gonzaga; Arruda, Francisco Vassiliepe Sousa; Vasconcelos, Mayron Alves; Carneiro, Victor Alves; Cavada, Benildo Sousa; Teixeira, Edson Holanda

2014-01-01

118

A novel universal DNA labeling and amplification system for rapid microarray-based detection of 117 antibiotic resistance genes in Gram-positive bacteria.  

PubMed

A rapid and simple DNA labeling system has been developed for disposable microarrays and has been validated for the detection of 117 antibiotic resistance genes abundant in Gram-positive bacteria. The DNA was fragmented and amplified using phi-29 polymerase and random primers with linkers. Labeling and further amplification were then performed by classic PCR amplification using biotinylated primers specific for the linkers. The microarray developed by Perreten et al. (Perreten, V., Vorlet-Fawer, L., Slickers, P., Ehricht, R., Kuhnert, P., Frey, J., 2005. Microarray-based detection of 90 antibiotic resistance genes of gram-positive bacteria. J.Clin.Microbiol. 43, 2291-2302.) was improved by additional oligonucleotides. A total of 244 oligonucleotides (26 to 37 nucleotide length and with similar melting temperatures) were spotted on the microarray, including genes conferring resistance to clinically important antibiotic classes like ?-lactams, macrolides, aminoglycosides, glycopeptides and tetracyclines. Each antibiotic resistance gene is represented by at least 2 oligonucleotides designed from consensus sequences of gene families. The specificity of the oligonucleotides and the quality of the amplification and labeling were verified by analysis of a collection of 65 strains belonging to 24 species. Association between genotype and phenotype was verified for 6 antibiotics using 77 Staphylococcus strains belonging to different species and revealed 95% test specificity and a 93% predictive value of a positive test. The DNA labeling and amplification is independent of the species and of the target genes and could be used for different types of microarrays. This system has also the advantage to detect several genes within one bacterium at once, like in Staphylococcus aureus strain BM3318, in which up to 15 genes were detected. This new microarray-based detection system offers a large potential for applications in clinical diagnostic, basic research, food safety and surveillance programs for antimicrobial resistance. PMID:25451460

Strauss, Christian; Endimiani, Andrea; Perreten, Vincent

2015-01-01

119

Transcriptional Attenuation Controls Macrolide Inducible Efflux and Resistance in Streptococcus pneumoniae and in Other Gram-Positive Bacteria Containing mef/mel(msr(D)) Elements  

PubMed Central

Macrolide resistance, emerging in Streptococcus pneumoniae and other Gram-positive bacteria, is increasingly due to efflux pumps encoded by mef/mel(msr) operons found on discrete mobile genetic elements. The regulation of mef/mel(msr) in these elements is not well understood. We identified the mef(E)/mel transcriptional start, localized the mef(E)/mel promoter, and demonstrated attenuation of transcription as a mechanism of regulation of macrolide-inducible mef-mediated macrolide resistance in S. pneumoniae. The mef(E)/mel transcriptional start site was a guanine 327 bp upstream of mef(E). Consensus pneumococcal promoter -10 (5?-TATACT-3?) and -35 (5?-TTGAAC-3?) boxes separated by 17 bp were identified 7 bp upstream of the start site. Analysis of the predicted secondary structure of the 327 5’ region identified four pairs of inverted repeats R1-R8 predicted to fold into stem-loops, a small leader peptide [MTASMRLR, (Mef(E)L)] required for macrolide induction and a Rho-independent transcription terminator. RNA-seq analyses provided confirmation of transcriptional attenuation. In addition, expression of mef(E)L was also influenced by mef(E)L-dependent mRNA stability. The regulatory region 5’ of mef(E) was highly conserved in other mef/mel(msr)-containing elements including Tn1207.1 and the 5612IQ complex in pneumococci and Tn1207.3 in Group A streptococci, indicating a regulatory mechanism common to a wide variety of Gram-positive bacteria containing mef/mel(msr) elements. PMID:25695510

Chancey, Scott T.; Bai, Xianhe; Kumar, Nikhil; Drabek, Elliott F.; Daugherty, Sean C.; Colon, Thomas; Ott, Sandra; Sengamalay, Naomi; Sadzewicz, Lisa; Tallon, Luke J.; Fraser, Claire M.; Tettelin, Hervé; Stephens, David S.

2015-01-01

120

Multicenter Evaluation of the Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Gram-Positive Aerobic Bacteria  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF) is gaining momentum as a tool for bacterial identification in the clinical microbiology laboratory. Compared with conventional methods, this technology can more readily and conveniently identify a wide range of organisms. Here, we report the findings from a multicenter study to evaluate the Vitek MS v2.0 system (bioMérieux, Inc.) for the identification of aerobic Gram-positive bacteria. A total of 1,146 unique isolates, representing 13 genera and 42 species, were analyzed, and results were compared to those obtained by nucleic acid sequence-based identification as the reference method. For 1,063 of 1,146 isolates (92.8%), the Vitek MS provided a single identification that was accurate to the species level. For an additional 31 isolates (2.7%), multiple possible identifications were provided, all correct at the genus level. Mixed-genus or single-choice incorrect identifications were provided for 18 isolates (1.6%). Although no identification was obtained for 33 isolates (2.9%), there was no specific bacterial species for which the Vitek MS consistently failed to provide identification. In a subset of 463 isolates representing commonly encountered important pathogens, 95% were accurately identified to the species level and there were no misidentifications. Also, in all but one instance, the Vitek MS correctly differentiated Streptococcus pneumoniae from other viridans group streptococci. The findings demonstrate that the Vitek MS system is highly accurate for the identification of Gram-positive aerobic bacteria in the clinical laboratory setting. PMID:23658261

Burnham, Carey-Ann D.; Bythrow, Maureen; Garner, Omai B.; Ginocchio, Christine C.; Jennemann, Rebecca; Lewinski, Michael A.; Manji, Ryhana; Mochon, A. Brian; Procop, Gary W.; Richter, Sandra S.; Sercia, Linda; Westblade, Lars F.; Ferraro, Mary Jane; Branda, John A.

2013-01-01

121

Pimarane-type diterpenes obtained by biotransformation: antimicrobial properties against clinically isolated Gram-positive multidrug-resistant bacteria.  

PubMed

The present study describes the antimicrobial activity of five pimarane-type diterpenes obtained by fungal biotransformation against several nosocomial multidrug-resistant bacteria. Among the investigated metabolites, ent-8(14),15-pimaradien-3?-ol was the most active compound, with very promising minimal inhibitory concentration values (between 8.0 and 25.0 µg mL(-1)). Time-kill assays using this metabolite against Staphylococcus aureus (HCRP180) revealed that this compound exerted its bactericidal effect within 24 h at all the evaluated concentrations (8.0, 16.0, and 24.0 µg mL(-1)). When this metabolite was associated with vancomycin at their minimal bactericidal concentration values, the resulting combination was able to drastically reduce the number of viable strains of S. aureus within the first 6 h, compared with these chemicals alone. The checkerboard assays conducted against this microorganism did not evidence any synergistic effects when this same combination was employed. In conclusion, our results point out that ent-8(14),15-pimaradien-3?-ol is an important metabolite in the search for new effective antimicrobial agents. PMID:23193079

Porto, Thiago S; Simão, Marília R; Carlos, Lucas Z; Martins, Carlos H G; Furtado, Niege A J C; Said, Suraia; Arakawa, Nilton S; dos Santos, Raquel A; Veneziani, Rodrigo C S; Ambrósio, Sérgio R

2013-10-01

122

Biocompatible Fe3O4 increases the efficacy of amoxicillin delivery against Gram-positive and Gram-negative bacteria.  

PubMed

This paper reports the synthesis and characterization of amoxicillin- functionalized magnetite nanostructures (Fe3O4@AMO), revealing and discussing several biomedical applications of these nanomaterials. Our results proved that 10 nm Fe3O4@AMO nanoparticles does not alter the normal cell cycle progression of cultured diploid cells, and an in vivo murine model confirms that the nanostructures disperse through the host body and tend to localize in particular sites and organs. The nanoparticles were found clustered especially in the lungs, kidneys and spleen, next to the blood vessels at this level, while being totally absent in the brain and liver, suggesting that they are circulated through the blood flow and have low toxicity. Fe3O4@AMO has the ability to be easily circulated through the body and optimizations may be done so these nanostructures cluster to a specific target region. Functionalized magnetite nanostructures proved a great antimicrobial effect, being active against both the Gram positive pathogen S. aureus and the Gram negative pathogen E. coli. The fabricated nanostructures significantly reduced the minimum inhibitory concentration (MIC) of the active drug. This result has a great practical relevance, since the functionalized nanostructures may be used for decreasing the therapeutic doses which usually manifest great severe side effects, when administrated in high doses. Fe3O4@AMO represents also a suitable approach for the development of new alternative strategies for improving the activity of therapeutic agents by targeted delivery and controlled release. PMID:24759068

Grumezescu, Alexandru Mihai; Gestal, Monica Cartelle; Holban, Alina Maria; Grumezescu, Valentina; Vasile, Bogdan Stefan; Mogoant?, Lauren?iu; Iordache, Florin; Bleotu, Coralia; Mogo?anu, George Dan

2014-01-01

123

Efficacy of 5-day parenteral versus intramammary benzylpenicillin for treatment of clinical mastitis caused by gram-positive bacteria susceptible to penicillin in vitro.  

PubMed

The efficacy of parenteral (intramuscular) or intramammary (IMM) benzylpenicillin treatment for clinical mastitis caused by gram-positive bacteria susceptible to penicillin in vitro was investigated. Cows with clinical mastitis in 1 udder quarter were randomly placed into 2 treatment groups. The preliminary bacteriological diagnosis of intramammary infection (IMI) was based on on-farm culturing, and the bacteriological diagnoses were later confirmed by a quantitative PCR assay. Clinical mastitis caused by gram-positive bacteria susceptible to benzylpenicillin was treated with penicillin via either the parenteral route (20mg/kg) or IMM route (600mg) once per day for 5d. The outcome of the treatment was evaluated 3 to 4wk after the onset of the treatment. The affected quarter was examined to assess the clinical cure, and milk samples were collected from the affected quarter to determine the bacteriological cure and milk N-acetyl-?-d-glucosaminidase activity. The survival and the composite milk somatic cell counts of the treated cows were followed up for 6 and 3mo after treatment, respectively. A total of 140 cows with clinical mastitis were included in the study, 61 being treated with benzylpenicillin parenterally and 79 via the IMM route. From all quarters treated, 108 of 140 (77.1%) were cured clinically and 77 of 140 (55.0%) were cured bacteriologically. The route of treatment did not significantly affect the outcome of the treatment; 80.3% of the quarters with parenteral treatment and 74.7% of the quarters with IMM treatment showed a clinical cure, and 54.1 and 55.7% a bacteriological cure, respectively. The milk N-acetyl-?-d-glucosaminidase activity was significantly lower in the quarters with a clinical or bacteriological cure than in the quarters with no cure. The 6-mo survival and the proportion of cows with composite milk somatic cell counts <200,000/mL among the treated cows during the 3-mo follow-up period did not significantly differ between the treatment groups. In conclusion, the outcome of either parenteral or IMM benzylpenicillin treatment of clinical mastitis caused by penicillin-susceptible bacteria was similar. PMID:24485692

Kalmus, P; Simojoki, H; Orro, T; Taponen, S; Mustonen, K; Holopainen, J; Pyörälä, S

2014-04-01

124

High-Throughput System for the Presentation of Secreted and Surface-Exposed Proteins from Gram-Positive Bacteria in Functional Metagenomics Studies  

PubMed Central

Complex microbial ecosystems are increasingly studied through the use of metagenomics approaches. Overwhelming amounts of DNA sequence data are generated to describe the ecosystems, and allow to search for correlations between gene occurrence and clinical (e.g. in studies of the gut microbiota), physico-chemical (e.g. in studies of soil or water environments), or other parameters. Observed correlations can then be used to formulate hypotheses concerning microbial gene functions in relation to the ecosystem studied. In this context, functional metagenomics studies aim to validate these hypotheses and to explore the mechanisms involved. One possible approach is to PCR amplify or chemically synthesize genes of interest and to express them in a suitable host in order to study their function. For bacterial genes, Escherichia coli is often used as the expression host but, depending on the origin and nature of the genes of interest and the test system used to evaluate their putative function, other expression systems may be preferable. In this study, we developed a system to evaluate the role of secreted and surface-exposed proteins from Gram-positive bacteria in the human gut microbiota in immune modulation. We chose to use a Gram-positive host bacterium, Bacillus subtilis, and modified it to provide an expression background that behaves neutral in a cell-based immune modulation assay, in vitro. We also adapted an E. coli – B. subtilis shuttle expression vector for use with the Gateway high-throughput cloning system. Finally, we demonstrate the functionality of this host-vector system through the cloning and expression of a flagellin-coding sequence, and show that the expression-clone elicits an inflammatory response in a human intestinal epithelial cell line. The expression host can easily be adapted to assure neutrality in other assay systems, allowing the use of the presented presentation system in functional metagenomics of the gut and other ecosystems. PMID:23799065

Dobrijevic, Dragana; Di Liberto, Gaetana; Tanaka, Kosei; de Wouters, Tomas; Dervyn, Rozenn; Boudebbouze, Samira; Binesse, Johan; Blottière, Hervé M.; Jamet, Alexandre; Maguin, Emmanuelle; van de Guchte, Maarten

2013-01-01

125

Detection of heavy metal ion resistance genes in gram-positive and gram-negative bacteria isolated from a lead-contaminated site.  

PubMed

Resistance to a range of heavy metal ions was determined for lead-resistant and other bacteria which had been isolated from a battery-manufacturing site contaminated with high concentration of lead. Several Gram-positive (belonging to the genera Arthrobacter and Corynebacterium) and Gram-negative (Alcaligenes species) isolates were resistant to lead, mercury, cadmium, cobalt, zinc and copper, although the levels of resistance to the different metal ions were specific for each isolate. Polymerase chain reaction, DNA-DNA hybridization and DNA sequencing were used to explore the nature of genetic systems responsible for the metal resistance in eight of the isolates. Specific DNA sequences could be amplified from the genomic DNA of all the isolates using primers for sections of the mer (mercury resistance determinant on the transposon Tn501) and pco (copper resistance determinant on the plasmid pRJ1004) genetic systems. Positive hybridizations with mer and pco probes indicated that the amplified segments were highly homologous to these genes. Some of the PCR products were cloned and partially sequenced, and the regions sequenced were highly homologous to the appropriate regions of the mer and pco determinants. These results demonstrate the wide distribution of mercury and copper resistance genes in both Gram-positive and Gram-negative isolates obtained from this lead-contaminated soil. In contrast, the czc (cobalt, zinc and cadmium resistance) and chr (chromate resistance) genes could not be amplified from DNAs of some isolates, indicating the limited contribution, if any, of these genetic systems to the metal ion resistance of these isolates. PMID:9342884

Trajanovska, S; Britz, M L; Bhave, M

1997-01-01

126

Structural basis for the De-N-acetylation of Poly-?-1,6-N-acetyl-D-glucosamine in Gram-positive bacteria.  

PubMed

Exopolysaccharides are required for the development and integrity of biofilms produced by a wide variety of bacteria. In staphylococci, partial de-N-acetylation of the exopolysaccharide poly-?-1,6-N-acetyl-d-glucosamine (PNAG) by the extracellular protein IcaB is required for biofilm formation. To understand the molecular basis for PNAG de-N-acetylation, the structure of IcaB from Ammonifex degensii (IcaBAd) has been determined to 1.7 Å resolution. The structure of IcaBAd reveals a (?/?)7 barrel common to the family four carbohydrate esterases (CE4s) with the canonical motifs circularly permuted. The metal dependence of IcaBAd is similar to most CE4s showing the maximum rates of de-N-acetylation with Ni(2+), Co(2+), and Zn(2+). From docking studies with ?-1,6-GlcNAc oligomers and structural comparison to PgaB from Escherichia coli, the Gram-negative homologue of IcaB, we identify Arg-45, Tyr-67, and Trp-180 as key residues for PNAG binding during catalysis. The absence of these residues in PgaB provides a rationale for the requirement of a C-terminal domain for efficient deacetylation of PNAG in Gram-negative species. Mutational analysis of conserved active site residues suggests that IcaB uses an altered catalytic mechanism in comparison to other characterized CE4 members. Furthermore, we identified a conserved surface-exposed hydrophobic loop found only in Gram-positive homologues of IcaB. Our data suggest that this loop is required for membrane association and likely anchors IcaB to the membrane during polysaccharide biosynthesis. The work presented herein will help guide the design of IcaB inhibitors to combat biofilm formation by staphylococci. PMID:25359777

Little, Dustin J; Bamford, Natalie C; Pokrovskaya, Varvara; Robinson, Howard; Nitz, Mark; Howell, P Lynne

2014-12-26

127

A Functional dlt Operon, Encoding Proteins Required for Incorporation of D-Alanine in Teichoic Acids in Gram-Positive Bacteria, Confers Resistance to Cationic Antimicrobial Peptides in Streptococcus pneumoniae  

Microsoft Academic Search

Streptococcus pneumoniae is one of the few species within the group of low-G C gram-positive bacteria reported to contain no D-alanine in teichoic acids, although the dltABCD operon encoding proteins responsible for D-alanylation is present in the genomes of two S. pneumoniae strains, the laboratory strain R6 and the clinical isolate TIGR4. The annotation of dltA in R6 predicts a

Marta Kovacs; Alexander Halfmann; Iris Fedtke; Manuel Heintz; Andreas Peschel; Waldemar Vollmer; Regine Hakenbeck; Reinhold Bruckner

2006-01-01

128

Phylogenetic Evidence that the Gram-Negative Nonsporulating Bacterium Tissierella (Bacteroides) praeacuta Is a Member of the Clostridium Subphylum of the Gram-Positive Bacteria and Description of Tissierella creatinini sp. nov  

Microsoft Academic Search

The 16s rRNA gene sequence of the type strain of Tissierella praeancta (formerly Bacteroides praeacutus) was determined by PCR direct sequencing. A comparative sequence analysis showed that T. praeacuta is a member of the Clostridium subphylum of the gram-positive bacteria and has a close phylogenetic affinity with the species that form Clostridiumduster XII (M. D. Collins, P. A. Lawson, k

J. A. E. FARROW; P. A. LAWSON; H. HIPPE; U. GAUGLITZ; M. D. COLLINS

129

Lagging strand replication of rolling-circle plasmids: Specific recognition of the ssoA-type origins in different gram-positive bacteria  

PubMed Central

Many bacterial plasmids replicate by a rolling-circle mechanism that involves the generation of single-stranded DNA (ssDNA) intermediates. Replication of the lagging strand of such plasmids initiates from their single strand origin (sso). Many different types of ssos have been identified. One group of ssos, termed ssoA, which have conserved sequence and structural features, function efficiently only in their natural hosts in vivo. To study the host specificity of sso sequences, we have analyzed the functions of two closely related ssoAs belonging to the staphylococcal plasmid pE194 and the streptococcal plasmid pLS1 in Staphylococcus aureus. The pLS1 ssoA functioned poorly in vivo in S. aureus as evidenced by accumulation of high levels of ssDNA but supported efficient replication in vitro in staphylococcal extracts. These results suggest that one or more host factors that are present in sufficient quantities in S. aureus cell-free extracts may be limiting in vivo. Mapping of the initiation points of lagging strand synthesis in vivo and in vitro showed that DNA synthesis initiates from specific sites within the pLS1 ssoA. These results demonstrate that specific initiation of replication can occur from the pLS1 ssoA in S. aureus although it plays a minimal role in lagging strand synthesis in vivo. Therefore, the poor functionality of the pLS1 in vivo in a nonnative host is caused by the low efficiency rather than a lack of specificity of the initiation process. We also have identified ssDNA promoters and mapped the primer RNAs synthesized by the S. aureus and Bacillus subtilis RNA polymerases from the pE194 and pLS1 ssoAs. The S. aureus RNA polymerase bound more efficiently to the native pE194 ssoA as compared with the pLS1 ssoA, suggesting that the strength of RNA polymerase–ssoA interaction may play a major role in the functionality of the ssoA sequences in Gram-positive bacteria. PMID:9724733

Kramer, M. Gabriela; Espinosa, Manuel; Misra, Tapan K.; Khan, Saleem A.

1998-01-01

130

Role of Intestinal Epithelial Cells in Immune Effects Mediated by Gram-Positive Probiotic Bacteria: Involvement of Toll-Like Receptors  

Microsoft Academic Search

The mechanisms by which probiotic bacteria exert their effects on the immune system are not completely understood, but the epithelium may be a crucial player in the orchestration of the effects induced. In a previous work, we observed that some orally administered strains of lactic acid bacteria (LAB) increased the number of immunoglobulin A (IgA)-producing cells in the small intestine

Gabriel Vinderola; Chantal Matar; Gabriela Perdigon

2005-01-01

131

In-Vitro, Anti-Bacterial Activities of Aqueous Extracts of Acacia catechu (L.F.)Willd, Castanea sativa, Ephedra sinica stapf and shilajita mumiyo Against Gram Positive and Gram Negative Bacteria  

PubMed Central

Objective: Evaluations of the in-vitro anti-bacterial activities of aqueous extracts of Acacia catechu (L.F.)Willd, Castanea sativa, Ephedra sinica stapf and Shilajita mumiyo against gram-positive bacteria (Staphylococcus aureus, Streptococcus pneumonia) and gram-negative bacteria (Escherichia coli, klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa) are reasonable since these ethnomedicinal plants have been used in Persian folk medicine for treating skin diseases, venereal diseases, respiratory problems and nervous disorders for ages. Methods: The well diffusion method (KB testing) with a concentration of 250 ?g/disc was used for evaluating the minimal inhibitory concentrations (MIC). Maximum synergistic effects of different combinations of components were also observed. Results: A particular combination of Acacia catechu (L.F.) Willd, Castanea sativa, Ephedra sinica stapf and shilajita mumiyo extracts possesses an outstanding anti-bacterial activity. It's inhibiting effect on microorganisms is significant when compared to the control group (P< 0.05). Staphylococcus aureus was the most sensitive microorganism. The highest antibacterial activity against gram-positive bacteria (Staphylococcus aureus, Streptococcus pneumonia) or gram-negative bacteria (Escherichia coli, Klebsiella pneumonia, Proteus mirabilis and Pseudomonas aeruginosa) was exerted by formula number 2 (Table1). Conclusion: The results reveal the presence of antibacterial activities of Acacia catechu, Castanea sativa husk, Ephedra sp. and Mumiyo against gram-positive and gram-negative bacteria. Synergistic effects in a combined formula, especially in formula number 2 (ASLAN?) can lead to potential sources of new antiseptic agents for treatment of acute or chronic skin ulcers. These results considering the significant antibacterial effect of the present formulation, support ethno-pharmacological uses against diarrheal and venereal diseases and demonstrate use of these plants to treat infectious diseases.

Dashtdar, Mehrab; Dashtdar, Mohammad Reza; Dashtdar, Babak; shirazi, Mohammad khabaz; Khan, Saeed Ahmad

2013-01-01

132

Evidence for the placement of the gram-negative Catonella morbi (Moore and Moore) and Johnsonella ignava (Moore and Moore) within the Clostridium subphylum of the gram-positive bacteria on the basis of 16S rRNA sequences.  

PubMed

Comparative 16S rRNA analysis was used to determine the phylogenetic positions of Catonella morbi and Johnsonella ignava, which are members of two monospecific genera of gram-negative anaerobic bacilli isolated from human gingival crevices. Both of these genera were found to belong to cluster XIVa (M. D. Collins, P. A. Lawson, A. Willems, J. J. Cordoba, J. Fernandez-Garayzabal, P. Garcia, J. Cai, H. Hippe, and J. A. E. Farrow, Int. J. Syst. Bacteriol. 44:812-826, 1994) of the Clostridium subphylum of gram-positive bacteria. Within this cluster, which contains several Clostridium, Coprococcus, Eubacterium, and Ruminococcus species, C. morbi and J. ignava formed two distinct lines that were separate from all other taxa. Our findings support the separate generic status of the genera Catonella and Johnsonella and show that these genera do not belong to the family Bacteroidaceae but instead belong to the gram-positive Clostridium subphylum. PMID:7547310

Willems, A; Collins, M D

1995-10-01

133

Effects of clinical mastitis caused by gram-positive and gram-negative bacteria and other organisms on the probability of conception in New York State Holstein dairy cows.  

PubMed

The objective of this study was to estimate the effects of different types of clinical mastitis (CM) on the probability of conception in New York State Holstein cows. Data were available on 55,372 artificial inseminations (AI) in 23,695 lactations from 14,148 cows in 7 herds. We used generalized linear mixed models to model whether or not a cow conceived after a particular AI. Independent variables included AI number (first, second, third, fourth), parity, season when AI occurred, farm, type of CM (due to gram-positive bacteria, gram-negative bacteria, or other organisms) in the 6 wk before and after an AI, and occurrence of other diseases. Older cows were less likely to conceive. Inseminations occurring in the summer were least likely to be successful. Retained placenta decreased the probability of conception. Conception was also less likely with each successive AI. The probability of conception associated with the first AI was 0.29. The probability of conception decreased to 0.26, 0.25, and 0.24 for the second, third, and fourth AI, respectively. Clinical mastitis occurring any time between 14 d before until 35 d after an AI was associated with a lower probability of conception; the greatest effect was an 80% reduction associated with gram-negative CM occurring in the week after AI. In general, CM due to gram-negative bacteria had a more detrimental effect on probability of conception than did CM caused by gram-positive bacteria or other organisms. Furthermore, CM had more effect on probability of conception immediately around the time of AI. Additional information about CM (i.e., its timing with respect to AI, and whether the causative agent is gram-positive or gram-negative bacteria, or other organisms) is valuable to dairy personnel in determining why some cows are unable to conceive in a timely manner. These findings are also beneficial for the management of mastitic cows (especially those with gram-negative CM) when mastitis occurs close to AI. PMID:20338432

Hertl, J A; Gröhn, Y T; Leach, J D G; Bar, D; Bennett, G J; González, R N; Rauch, B J; Welcome, F L; Tauer, L W; Schukken, Y H

2010-04-01

134

TNF-? hyper-responses to Gram-negative and Gram-positive bacteria in Propionibacterium acnes primed or Salmonella typhimurium infected mice  

Microsoft Academic Search

IFN-?-dependent hypersensitivity to LPS is inducible in mice by infection or pre-treatment with killed bacteria. Hypersensitive mice exhibit enhanced inflammatory responses to LPS, including the overproduction of TNF-?. Using Lpsn BALB\\/c and Lpsd BALB\\/c\\/l mice, primed with Propionibacterium acnes or infected with Salmonella typhimurium, we show that concurrently to hypersensitivity to LPS, a hypersensitivity to other constituents of killed Gram-negative

Thomas Merlin; Marina Gumenscheimer; Chris Galanos; Marina A. Freudenberg

2001-01-01

135

Differential modulation of the induction of inflammatory mediators by antibiotics in mouse macrophages in response to viable Gram-positive and Gram-negative bacteria  

Microsoft Academic Search

We have investigated effects of ?-lactam antibiotics on TNF-?, and iNOS production from mouse peritoneal macrophages following co-culture with Escherichia coli or Staphylococcus aureus bacteria. Ceftazidime and aztreonam enhanced TNF-? secretion from macrophages stimulated with E. coli; however, imipenem does not alter either the kinetics or magnitude of TNF-? in E. coli -treated macrophages. Similar treatments with S. aureus co-cultured

Wei Cui; Mei-Guey Lei; Richard Silverstein; David C. Morrison

2003-01-01

136

Isolation and characterization of four novel Gram-positive bacteria associated with the rhizosphere of two endemorelict plants capable of degrading a broad range of aromatic substrates  

Microsoft Academic Search

Four new Gram-positive, phenol-degrading strains were isolated from the rhizospheres of endemorelict plants Ramonda serbica and Ramonda nathaliae known to exude high amounts of phenolics in the soil. Isolates were designated Bacillus sp. PS1, Bacillus sp. PS11, Streptomyces sp. PS12, and Streptomyces sp. PN1 based on 16S rDNA sequence and biochemical analysis. In addition to their ability to tolerate and

Lidija Djokic; Tanja Narancic; Jasmina Nikodinovic-Runic; Miloje Savic; Branka Vasiljevic

2011-01-01

137

Heavy metal resistance and genotypic analysis of metal resistance genes in gram-positive and gram-negative bacteria present in Ni-rich serpentine soil and in the rhizosphere of Alyssum murale.  

PubMed

Forty-six bacterial cultures, including one culture collection strain, thirty from the rhizosphere of Alyssum murale and fifteen from Ni-rich soil, were tested for their ability to tolerate arsenate, cadmium, chromium, zinc, mercury, lead, cobalt, copper, and nickel in their growth medium. The resistance patterns, expressed as minimum inhibitory concentrations, for all cultures to the nine different metal ions were surveyed by using the agar dilution method. A large number of the cultures were resistant to Ni (100%), Pb (100%), Zn (100%), Cu (98%), and Co (93%). However, 82, 71, 58 and 47% were sensitive to As, Hg, Cd and Cr(VI), respectively. All cultures had multiple metal-resistant, with heptametal resistance as the major pattern (28.8%). Five of the cultures (about of 11.2% of the total), specifically Arthrobacter rhombi AY509239, Clavibacter xyli AY509235, Microbacterium arabinogalactanolyticum AY509226, Rhizobium mongolense AY509209 and Variovorax paradoxus AY512828 were tolerant to nine different metals. The polymerase chain reaction in combination with DNA sequence analysis was used to investigate the genetic mechanism responsible for the metal resistance in some of these gram-positive and gram-negative bacteria that were, highly resistant to Hg, Zn, Cr and Ni. The czc, chr, ncc and mer genes that are responsible for resistance to Zn, Cr, Ni and Hg, respectively, were shown to be present in these bacteria by using PCR. In the case of, M. arabinogalactanolyticum AY509226 these genes were shown to have high homology to the czcD, chrB, nccA, and mer genes of Ralstonia metallidurans CH34. Therefore, Hg, Zn, Cr and Ni resistance genes are widely distributed in both gram-positive and gram-negative isolates obtained from A. murale rhizosphere and Ni-rich soils. PMID:17276484

Abou-Shanab, R A I; van Berkum, P; Angle, J S

2007-06-01

138

Noncovalent association of protein and capsular polysaccharide on bacteria-sized latex beads as a model for polysaccharide-specific humoral immunity to intact gram-positive extracellular bacteria.  

PubMed

Intact Streptococcus pneumoniae expressing type 14 capsular polysaccharide (PPS14) and type III S. agalactiae containing a PPS14 core capsule identical to PPS14 exhibit noncovalent associations of PPS14 and bacterial protein, in contrast to soluble covalent conjugates of these respective Ags. Both bacteria and conjugates induce murine PPS14-specific IgG responses dependent on CD4? T cells. Further, secondary immunization with conjugate and S. agalactiae, although not S. pneumoniae, results in a boosted response. However, in contrast to conjugate, PPS14-specific IgG responses to bacteria lack affinity maturation use the 44.1-idiotype and are dependent on marginal zone B cells. To better understand the mechanism underlying this dichotomy, we developed a minimal model of intact bacteria in which PPS14 and pneumococcal surface protein A (PspA) were stably attached to 1 ?m (bacteria-sized) latex beads, but not directly linked to each other, in contrast to PPS14-PspA conjugate. Beads coated simultaneously with PPS14+[PspA], similar to conjugate, induced in mice boosted PPS14-specific IgG secondary responses, dependent on T cells and ICOS-dependent costimulation, and in which priming could be achieved with PspA alone. In contrast to conjugate, but similar to intact bacteria, the primary PPS14-specific IgG response to beads coated simultaneously with PPS14+[PspA] peaked rapidly, with the secondary response highly enriched for the 44.1-idiotype and lacking affinity maturation. These results demonstrate that noncovalent association in a particle, of polysaccharide and protein, recapitulates essential immunologic characteristics of intact bacteria that are distinct from soluble covalent conjugates of these respective Ags. PMID:23926322

Colino, Jesus; Duke, Leah; Snapper, Clifford M

2013-09-15

139

Non-covalent association of protein and capsular polysaccharide on bacteria-sized latex beads as a model for polysaccharide-specific humoral immunity to intact Gram-positive extracellular bacteria1  

PubMed Central

Intact Streptococcus pneumoniae, expressing type 14 capsular polysaccharide (PPS14) and type III Streptococcus agalactiae containing a PPS14 core capsule identical to PPS14, exhibit non-covalent associations of PPS14 and bacterial protein, in contrast to soluble covalent conjugates of these respective antigens. Both bacteria and conjugates induce murine PPS14-specific IgG responses dependent on CD4+ T cells. Further, secondary immunization with conjugate and S. agalactiae, although not S. pneumoniae, results in a boosted response. However, in contrast to conjugate, PPS14-specific IgG responses to bacteria lack affinity maturation, utilize the 44.1-idiotype and are dependent on marginal zone B cells. To better understand the mechanism underlying this dichotomy we developed a minimal model of intact bacteria in which PPS14 and pneumococcal surface protein A (PspA) were stably attached to 1 ?m (bacteria-sized) latex beads, but not directly linked to each other, in contrast to PPS14-PspA conjugate. PPS14+[PspA] beads, similar to conjugate, induced in mice boosted PPS14-specific IgG secondary responses, dependent on T cells and ICOS-dependent costimulation, and in which priming could be achieved with PspA alone. In contrast to conjugate, but similar to intact bacteria, the primary PPS14-specific IgG response to PPS14+[PspA] beads peaked rapidly, with the secondary response highly enriched for the 44.1-idiotype and lacking affinity maturation. These results demonstrate that non-covalent association in a particle, of polysaccharide and protein, recapitulates essential immunologic characteristics of intact bacteria that are distinct from soluble covalent conjugates of these respective antigens. PMID:23926322

Colino, Jesus; Duke, Leah; Snapper, Clifford M.

2013-01-01

140

The effect of recurrent episodes of clinical mastitis caused by gram-positive and gram-negative bacteria and other organisms on mortality and culling in Holstein dairy cows.  

PubMed

The objective of this study was to estimate the effects of recurrent episodes of different types of clinical mastitis (CM) caused by gram-positive (Streptococcus spp., Staphylococcus aureus, Staphylococcus spp.) and gram-negative (Escherichia coli, Klebsiella, Citrobacter, Enterobacter, Pseudomonas) bacteria, and other organisms (Arcanobacterium pyogenes, Mycoplasma, Corynebacterium bovis, yeast, miscellaneous) on the probability of mortality and culling in Holstein dairy cows. Data from 30,233 lactations in cows of 7 dairy farms in New York State were analyzed. Cows were followed for the first 10 mo in lactation, or until death or culling occurred, or until the end of our study period. Generalized linear mixed models with a Poisson error distribution were used to study the effects of recurrent cases of the different types of CM and several other factors (herd, parity, month of lactation, current year and season, profitability, net replacement cost, other diseases) on cows' probability of death (model 1) or being culled (model 2). Primiparous and multiparous cows were modeled separately because they had different risks of mortality and culling and potentially different CM effects on mortality and culling. Approximately 30% of multiparous cows had at least one case of CM in lactation compared with 16.6% of primiparous cows. Multipara also had higher lactational incidence risks of second (10.7%) and third (4.4%) cases than primipara (3.7% and 1.1%, respectively). For primipara, CM increased the probability of death, with each successive case occurring in a month being increasingly lethal. In multipara, gram-negative CM increased the probability of death, especially when the gram-negative case was the first or second CM case in lactation. Primiparous cows with CM were more likely to be culled after CM than if they did not have CM, particularly after a second or third case. In multipara, any type of CM increased the probability of being culled. Gram-negative CM cases were associated with the numerically highest risk of culling. PMID:21943738

Hertl, J A; Schukken, Y H; Bar, D; Bennett, G J; González, R N; Rauch, B J; Welcome, F L; Tauer, L W; Gröhn, Y T

2011-10-01

141

Genomics of Probiotic Bacteria  

NASA Astrophysics Data System (ADS)

Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.

O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.

142

BOGUS BACTERIA...  

NSDL National Science Digital Library

Here are some websites to get you started... Just click on the links and start searching! microbe world- bacteria Bacteria Rule Quiz! Bacteria.... Harmful Bacteria Bacteria Museum Bacteria! Microbes- all sorts of info... When you are finished looking at the sites or when you have enough information concerning bacteria, ask Mrs. Deaton for some books that can give you even more DETAIL!!! *Don\\'t forget to keep track of your information on your I-CHARTS... ...

Mrs. Deaton

2007-01-24

143

Transcriptional cross-regulation between Gram-negative and gram-positive bacteria, demonstrated using ArgP-argO of Escherichia coli and LysG-lysE of Corynebacterium glutamicum.  

PubMed

The protein-gene pairs ArgP-argO of Escherichia coli and LysG-lysE of Corynebacterium glutamicum are orthologous, with the first member of each pair being a LysR-type transcriptional regulator and the second its target gene encoding a basic amino acid exporter. Whereas LysE is an exporter of arginine (Arg) and lysine (Lys) whose expression is induced by Arg, Lys, or histidine (His), ArgO exports Arg alone, and its expression is activated by Arg but not Lys or His. We have now reconstituted in E. coli the activation of lysE by LysG in the presence of its coeffectors and have shown that neither ArgP nor LysG can regulate expression of the noncognate orthologous target. Of several ArgP-dominant (ArgP(d)) variants that confer elevated Arg-independent argO expression, some (ArgP(d)-P274S, -S94L, and, to a lesser extent, -P108S) activated lysE expression in E. coli. However, the individual activating effects of LysG and ArgP(d) on lysE were mutually extinguished when both proteins were coexpressed in Arg- or His-supplemented cultures. In comparison with native ArgP, the active ArgP(d) variants exhibited higher affinity of binding to the lysE regulatory region and less DNA bending at both argO and lysE. We conclude that the transcription factor LysG from a Gram-positive bacterium, C. glutamicum, is able to engage appropriately with the RNA polymerase from a Gram-negative bacterium, E. coli, for activation of its cognate target lysE in vivo and that single-amino-acid-substitution variants of ArgP can also activate the distantly orthologous target lysE, but by a subtly different mechanism that renders them noninterchangeable with LysG. PMID:22904281

Marbaniang, Carmelita N; Gowrishankar, J

2012-10-01

144

Ethanol production in Gram-positive microbes  

DOEpatents

The subject invention concerns the transformation of Gram-positive bacteria with heterologous genes which confer upon these microbes the ability to produce ethanol as a fermentation product. Specifically exemplified is the transformation of bacteria with genes, obtainable from Zymomonas mobilis, which encode pyruvate decarboxylase and alcohol dehydrogenase. 2 figs.

Ingram, L.O.; Barbosa-Alleyne, M.D.F.

1996-01-09

145

Ethanol production in Gram-positive microbes  

DOEpatents

The subject invention concerns the transformation of Gram-positive bacteria with heterologous genes which confer upon these microbes the ability to produce ethanol as a fermentation product. Specifically exemplified is the transformation of bacteria with genes, obtainable from Zymomonas mobilis, which encode pyruvate decarboxylase and alcohol dehydrogenase.

Ingram, Lonnie O'Neal (Gainesville, FL); Barbosa-Alleyne, Maria D. F. (Gainesville, FL)

1996-01-01

146

Ethanol production in gram-positive microbes  

DOEpatents

The subject invention concerns the transformation of Gram-positive bacteria with heterologous genes which confer upon these microbes the ability to produce ethanol as a fermentation product. Specifically exemplified is the transformation of bacteria with genes, obtainable from Zymomonas mobilis, which encode pyruvate decarboxylase and alcohol dehydrogenase.

Ingram, Lonnie O'Neal (Gainesville, FL); Barbosa-Alleyne, Maria D. F. (Gainesville, FL)

1999-01-01

147

Ethanol production in Gram-positive microbes  

DOEpatents

The subject invention concerns the transformation of Gram-positive bacteria with heterologous genes which confer upon these microbes the ability to produce ethanol as a fermentation product. Specifically exemplified is the transformation of bacteria with genes, obtainable from Zymomonas mobilis, which encode pyruvate decarboxylase and alcohol dehydrogenase. 2 figs.

Ingram, L.O.; Barbosa-Alleyne, M.D.F.

1999-06-29

148

QUORUM SENSING IN BACTERIA  

Microsoft Academic Search

? Abstract Quorum sensing is the regulation of gene expression in response to fluctuations in cell-population density. Quorum sensing bacteria produce and release chemical signal molecules called autoinducers that increase in concentration as a function of cell density. The detection of a minimal threshold stimulatory con- centration of an autoinducer leads to an alteration in gene expression. Gram-positive and Gram-negative

Melissa B. Miller; Bonnie L. Bassler

2001-01-01

149

Spirochaetes Hyperthermophilic bacteriaCyanobacteriaLow-GC Gram-positives  

E-print Network

Gnetophytes Ginkgo Cycads Ferns Horsetails Whiskferns Clubmossesandrelatives Hornworts Mosses Liverworts Parabasalids Diplomonads ForaminiferansCercozoansRadiolarians Amoebozoans Club Fungi Sac Fungi Arbuscular

Hillis, David

150

Bacteria Museum  

NSDL National Science Digital Library

Who knew that bacteria had their own virtual museum? Here, visitors will "learn that not all bacteria are harmful, how they are used in industry, that they belong to the oldest living creatures on Earth", and many more interesting facts to discover about the diverse world of bacteria. The "Bacterial Species Files" tab at the top of the page, allows visitors to look up information on 40 different specific bacteria, from Anthrax to Yersinia enterocolitica. The information provided for each bacterium includes photographs, consumer guides, fact sheets, and scientific links. Visitors will find that the "Main Exhibits" tab addresses the basics about bacteria, as well as "Pathogenic Bacteria", "Evolution", "How We Fight Bacteria", and "Food and Water Safety". Visitors will surely enjoy the "Good Bacteria in Food" link found in the Food and Water Safety section, as it explains how some foods benefit from good bacteria, such as Swiss cheese, sausage, sauerkraut, chocolate, and coffee.

151

Accentuate the (Gram) positive Victor Nizet  

E-print Network

research. Streptococcus pneumoniae (SPN) is a leading agent of pneumonia, meningitis and sepsis throughout January 2010 # Springer-Verlag 2010 Keywords Gram-positive bacteria . Streptococcus . Special issue [7]. The mechanisms of SPN invasion to produce lower respiratory tract, pneumonia, and meningitis

Nizet, Victor

152

Bacteria Transformation  

NSDL National Science Digital Library

Students construct paper recombinant plasmids to simulate the methods genetic engineers use to create modified bacteria. They learn what role enzymes, DNA and genes play in the modification of organisms. For the particular model they work on, they isolate a mammal insulin gene and combine it with a bacteria's gene sequence (plasmid DNA) for production of the protein insulin.

2014-09-18

153

Effect of Diet on Amino and Nucleic Acids of Rumen Bacteria and Protozoa1  

Microsoft Academic Search

Amino acid composition and nucleic acid content of pure cultures of rumen bacteria (17 species) were analyzed. Amino acid composition between gram- positive and -negative organisms was not different. The total nitrogen content of gram-negative bacteria (10.8%) was signif- icantly higher than gram-positive or- ganisms (9.9%). Deoxyribonucleic acid- nitrogen:total nitrogen (rag\\/g) differed between gram-positive (8.8) and gram- negative (18.9) bacteria,

M. J. Arambel; E. E. Bartley; G. S. Dufva; T. G. Nagaraja; A. D. Dayton

1982-01-01

154

[Sorption of humic acids by bacteria].  

PubMed

Capacity for sorption of humic acid (HA) from water solutions was shown for 38 bacterial strains. Isotherms of HA sorption were determined for the cells of 10 strains. The bonding strength between the cells and HA (k) and the terminal adsorption (Q(max)) determined from the Langmuir equation for gram-positive and gram-negative bacteria were reliably different. Gram-positive bacteria sorbed greater amounts of HA than gram-negative ones (Q(max) = 23 ± 10 and 5.6 ± 1.2 mg/m2, respectively). The bonding strength between HA and the cells was higher in gram-negative bacteria than in gram-positive: k = 9 ± 5 and 3.3 ± 1.1 mL/mg, respectively. PMID:25509407

Tikhonov, V V; Orlov, D S; Lisovitskaia, O V; Zavgorodniaia, Iu A; Byzov, B A; Demin, V V

2013-01-01

155

ISOLATION AND CHARACTERIZATION OF HALOTOLERANT AEROBIC BACTERIA FROM OIL RESERVOIR  

Microsoft Academic Search

Several halotolerant bacteria were isolated from brine samples from Semangkok oil reservoir. Biochemical and morphological characterization of the bacteria were carried out. These bacteria are gram positive spore formers and have been identified as belonging to the genus Bacillus. Most of the isolates could grow in medium containing kerosene as sole carbon source and energy and tolerate NaCl concentration up

ROSLI M. D. ILLIAS; OOI SEOK WEI; AHMAD KAMAL IDRIS; WAN AIZAN; WAN ABDUL

156

Clinical microbiology of coryneform bacteria.  

PubMed Central

Coryneform bacteria are aerobically growing, asporogenous, non-partially-acid-fast, gram-positive rods of irregular morphology. Within the last few years, there has been a massive increase in the number of publications related to all aspects of their clinical microbiology. Clinical microbiologists are often confronted with making identifications within this heterogeneous group as well as with considerations of the clinical significance of such isolates. This review provides comprehensive information on the identification of coryneform bacteria and outlines recent changes in taxonomy. The following genera are covered: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter. Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, "Corynebacterium aquaticum," Arcanobacterium, and Actinomyces. Case reports claiming disease associations of coryneform bacteria are critically reviewed. Minimal microbiological requirements for publications on disease associations of coryneform bacteria are proposed. PMID:8993861

Funke, G; von Graevenitz, A; Clarridge, J E; Bernard, K A

1997-01-01

157

Parasitic Bacteria  

E-print Network

species and 2 varieties of bacteria parasitic on plants in Ohio. Bacterial plant diseases in Ohio, such as alfalfa wilt, cucurbit wilt, corn leaf blight and wilt (Stewart's disease), fire blight of apple and pear, FIGURE 1. Bacterial wilt of carnation. crown gall, soft rot of many vegetables, and

Ellett C. Wayne; C. W. Ellett; C. W. Ellett; Plate I

158

Magnetotactic Bacteria  

Microsoft Academic Search

Bacteria with motility directed by the local geomagnetic field have been observed in marine sediments. These magnetotactic microorganisms possess flagella and contain novel structured particles, rich in iron, within intracytoplasmic membrane vesicles. Conceivably these particles impart to cells a magnetic moment. This could explain the observed migration of these organisms in fields as weak as 0.5 gauss.

Richard Blakemore

1975-01-01

159

Endophytic bacteria in Coffea arabica L.  

PubMed

Eighty-seven culturable endophytic bacterial isolates in 19 genera were obtained from coffee plants collected in Colombia (n = 67), Hawaii (n = 17), and Mexico (n = 3). Both Gram positive and Gram negative bacteria were isolated, with a greater percentage (68%) being Gram negative. Tissues yielding bacterial endophytes included adult plant leaves, various parts of the berry (e.g., crown, pulp, peduncle and seed), and leaves, stems, and roots of seedlings. Some of the bacteria also occurred as epiphytes. The highest number of bacteria among the berry tissues sampled was isolated from the seed, and includes Bacillus , Burkholderia , Clavibacter , Curtobacterium , Escherichia , Micrococcus , Pantoea , Pseudomonas , Serratia , and Stenotrophomonas . This is the first survey of the endophytic bacteria diversity in various coffee tissues, and the first study reporting endophytic bacteria in coffee seeds. The possible role for these bacteria in the biology of the coffee plant remains unknown. PMID:16187260

Vega, Fernando E; Pava-Ripoll, Monica; Posada, Francisco; Buyer, Jeffrey S

2005-01-01

160

Production of Value-added Products by Lactic Acid Bacteria  

Technology Transfer Automated Retrieval System (TEKTRAN)

Lactic acid bacteria (LAB) are a group of facultative anaerobic, catalase negative, nonmotile and nonsporeforming–Gram positive bacteria. Most LAB utilize high energy C sources including monomer sugars to produce energy to maintain cellular structure and function. This anaerobic fermentation proce...

161

Biological Characterization of Novel Inhibitors of the Gram-Positive DNA Polymerase IIIC Enzyme  

Microsoft Academic Search

Novel N-3-alkylated 6-anilinouracils have been identified as potent and selective inhibitors of bacterial DNA polymerase IIIC, the enzyme essential for the replication of chromosomal DNA in gram-positive bacteria. A nonradioactive assay measuring the enzymatic activity of the DNA polymerase IIIC in gram-positive bacteria has been assembled. The 6-anilinouracils described inhibited the polymerase IIIC enzyme at concentrations in the nanomolar range

Alexander Kuhl; Niels Svenstrup; Christoph Ladel; Michael Otteneder; Annegret Binas; Guido Schiffer; Michael Brands; Thomas Lampe; Karl Ziegelbauer; Helga Rubsamen-Waigmann; Dieter Haebich; Kerstin Ehlert

2005-01-01

162

Evaluation of a fluorescent lectin-based staining technique for some acidophilic mining bacteria  

SciTech Connect

A fluorescence-labeled wheat germ agglutinin staining technique was modified and found to be effective for staining gram-positive, acidophilic mining bacteria. Bacteria identified by others as being gram positive through 16S rRNA sequence analyses, yet clustering near the divergence of that group, stained weakly. Gram-negative bacteria did not stain. Background staining of environmental samples was negligible, and pyrite and soil particles in the samples did not interfere with the staining procedure.

Fife, D.J.; Bruhn, D.F.; Miller, K.S.; Stoner, D.L.

2000-05-01

163

Magnetic bacteria against MIC  

SciTech Connect

In this article, it is suggested to use the sensitivity of magnetotactic bacteria to changes of magnetic field direction and the natural ability of this bacteria in rapid growth during relatively short time intervals against corrosion-enhancing bacteria and especially sulfate-reducing bacteria. If colonies of sulfate-reducing bacteria could be packed among magnetotactic bacteria, then, by applying sufficiently powerful magnetic field (about 0.5 gauss), all of these bacteria (magnetic and non-magnetic) will be oriented towards an Anti-bacteria agent (oxygen or biocide). So, Microbiologically-Influenced Corrosion in the system would be controlled to a large extent.

Javaherdashti, R. [I.D.R.O.-IR, Tehran (Iran, Islamic Republic of)

1997-12-01

164

Back To Bacteria.  

ERIC Educational Resources Information Center

Explores new research about bacteria. Discusses bacterial genomes, archaea, unusual environments, evolution, pathogens, bacterial movement, biofilms, bacteria in the body, and a bacterial obsession. Contains 29 references. (JRH)

Flannery, Maura C.

1997-01-01

165

The Museum of Bacteria  

NSDL National Science Digital Library

The Museum of Bacteria serves as a clearinghouse of Web links on bacteria and bacteriology and also provides "crystal-clear information about many aspects of bacteria." The Museum of Bacteria is provided by the Foundation of Bacteria, a non-profit organization dedicated to promoting the field of bacteriology. Links are selected for a general audience, although one section is geared toward professionals in the field. Some of the latest features of the Museum are an "exhibit" on the good bacteria found in food and a Student Hall where students can present their own bacteria-related projects.

166

Peptides 25 (2004) 14251440 Peptide signal molecules and bacteriocins in Gram-negative bacteria: a  

E-print Network

-negative bacteria: a genome-wide in silico screening for peptides containing a double-glycine leader sequence Abstract Quorum sensing (QS) in Gram-negative bacteria is generally assumed to be mediated by N-acyl-homoserine lactone molecules while Gram-positive bacteria make use of signaling peptides. We analyzed the occurrence

167

Cadmium uptake and resistance among selected bacteria  

SciTech Connect

The purpose of this research was to determine the relationship between Cd resistance and Cd uptake by lake sediment bacteria. For the Gram positive and gram negative sediment bacteria that were tested, the relationship between resistance and Cd uptake varied and was dependent on the isolate under consideration. Results of this study indicated that bacterial communities in lake sediments may influence the concentration and availability of Cd in sediments and the water column. In addition, results of this study did not support the theory that the genes encoding for Cd resistance are usually carried on antibiotic resistance plasmids.

Burke, B.E.

1987-01-01

168

Virulence Plasmids of Nonsporulating Gram-Positive Pathogens  

PubMed Central

SUMMARY Gram-positive bacteria are leading causes of many types of human infection, including pneumonia, skin and nasopharyngeal infections, as well as urinary tract and surgical wound infections among hospitalized patients. These infections have become particularly problematic because many of the species causing them have become highly resistant to antibiotics. The role of mobile genetic elements, such as plasmids, in the dissemination of antibiotic resistance among Gram-positive bacteria has been well studied; less well understood is the role of mobile elements in the evolution and spread of virulence traits among these pathogens. While these organisms are leading agents of infection, they are also prominent members of the human commensal ecology. It appears that these bacteria are able to take advantage of the intimate association between host and commensal, via virulence traits that exacerbate infection and cause disease. However, evolution into an obligate pathogen has not occurred, presumably because it would lead to rejection of pathogenic organisms from the host ecology. Instead, in organisms that exist as both commensal and pathogen, selection has favored the development of mechanisms for variability. As a result, many virulence traits are localized on mobile genetic elements, such as virulence plasmids and pathogenicity islands. Virulence traits may occur within a minority of isolates of a given species, but these minority populations have nonetheless emerged as a leading problem in infectious disease. This chapter reviews virulence plasmids in nonsporulating Gram-positive bacteria, and examines their contribution to disease pathogenesis. PMID:25544937

Van Tyne, Daria; Gilmore, Michael S.

2014-01-01

169

Bacteria isolated from amoebae/bacteria consortium  

DOEpatents

New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

Tyndall, R.L.

1995-05-30

170

Bacteria isolated from amoebae/bacteria consortium  

DOEpatents

New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

Tyndall, Richard L. (Clinton, TN)

1995-01-01

171

Bioelectricity Aware of bacteria  

E-print Network

that are responsible. To verify this hypothesis, they genetically modified bacteria to replace in the pili, these amino acids with alanine, aliphatic*. Result: the genetically changed bacteria does drive more electricity

Lovley, Derek

172

Bleach vs. Bacteria  

MedlinePLUS

... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

173

Lactic Acid Bacteria  

NSDL National Science Digital Library

This on-line exercise is focused on lactic acid bacteria, a group of related bacteria that produce lactic acid as a result of carbohydrate fermentation. It includes a protocol for the enrichment of lactic acid bacteria from enriched samples (like yogurt, sauerkraut, decaying plant matter, and tooth plaque). Three parameters are measured: growth, culture diversity, and pH. The exercise also includes instructions for the isolation of some of these bacteria by using the streak-plate method.

174

Cell Size Regulation in Bacteria  

NASA Astrophysics Data System (ADS)

Various bacteria such as the canonical gram negative Escherichia coli or the well-studied gram positive Bacillus subtilis divide symmetrically after they approximately double their volume. Their size at division is not constant, but is typically distributed over a narrow range. Here, we propose an analytically tractable model for cell size control, and calculate the cell size and interdivision time distributions, as well as the correlations between these variables. We suggest ways of extracting the model parameters from experimental data, and show that existing data for E. coli supports partial size control, and a particular explanation: a cell attempts to add a constant volume from the time of initiation of DNA replication to the next initiation event. This hypothesis accounts for the experimentally observed correlations between mother and daughter cells as well as the exponential dependence of size on growth rate.

Amir, Ariel

2014-05-01

175

CHAPTER IV-2 BACTERIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Entomopathogenic bacteria provide an alternative to chemical pesticides used in insect control programs. Today, the principal microbial insecticides utilize spore forming bacteria or toxins produced by these bacteria as their active ingredients, either in formulations or by incorporation of toxin g...

176

Bacteria: More Than Pathogens  

NSDL National Science Digital Library

The issue-focused, peer-reviewed article reveals that there are more bacteria on Earth than there are humans. Bacteria: inhabit every environment on the planet, playing a key ecological role, can be good for our health -- for example, by helping us digest food, and can cause disease even though the human body is not the natural host for many bacteria.

Trudy Wassenaar (; )

2002-07-01

177

Bacteria: Friend or Foe?  

NSDL National Science Digital Library

This lesson explores "good" and "bad" bacteria. Students can draw "Wanted!" bacteria mug shots, create composting trials and designs, produce a skit involving a boastful virus and bacterium, experiment with soil and ordinary objects in the lab, write a news story about an outbreak, complete a multiple-choice bacteria quiz and more!

David Brock (Roland Park Public School; )

2003-01-10

178

Ultrasound-Mediated DNA Transformation in Thermophilic Gram-Positive Anaerobes  

Microsoft Academic Search

BackgroundThermophilic, Gram-positive, anaerobic bacteria (TGPAs) are generally recalcitrant to chemical and electrotransformation due to their special cell-wall structure and the low intrinsic permeability of plasma membranes.Methodology\\/Principal FindingsHere we established for any Gram-positive or thermophiles an ultrasound-based sonoporation as a simple, rapid, and minimally invasive method to genetically transform TGPAs. We showed that by applying a 40 kHz ultrasound frequency over

Lu Lin; Houhui Song; Yuetong Ji; Zhili He; Yunting Pu; Jizhong Zhou; Jian Xu

2010-01-01

179

Bacteria Are Everywhere!  

NSDL National Science Digital Library

Students are introduced to the concept of engineering biological organisms and studying their growth to be able to identify periods of fast and slow growth. They learn that bacteria are found everywhere, including on the surfaces of our hands. Student groups study three different conditions under which bacteria are found and compare the growth of the individual bacteria from each source. In addition to monitoring the quantity of bacteria from differ conditions, they record the growth of bacteria over time, which is an excellent tool to study binary fission and the reproduction of unicellular organisms.

AMPS GK-12 Program,

180

AEROBIC SALIVARY BACTERIA IN WILD AND CAPTIVE KOMODO DRAGONS  

Microsoft Academic Search

During the months of November 1996, August 1997, and March 1998, saliva and plasma samples were collected for isolation of aerobic bacteria from 26 wild and 13 captive Komodo dragons (Varanus komodoensis). Twenty-eight Gram-negative and 29 Gram-positive spe- cies of bacteria were isolated from the saliva of the 39 Komodo dragons. A greater number of wild than captive dragons were

Joel M. Montgomery; Don Gillespie; Putra Sastrawan; Terry M. Fredeking; George L. Stewart

2002-01-01

181

Desorption electrospray ionization mass spectrometry of intact bacteria  

Technology Transfer Automated Retrieval System (TEKTRAN)

Desorption electrospray ionization (DESI) mass spectrometry (MS) was used to differentiate 7 bacterial species based on their measured DESI-mass spectral profile. Both Gram positive and Gram negative bacteria were tested and included Escherichia coli, Staphyloccocus aureus, Enterococcus sp., Bordete...

182

Culturable Airborne Bacteria in Outdoor Poultry-Slaughtering Facility  

PubMed Central

Airborne bacteria are important biological components of the aerosols and have a close relationship with human health as they can have adverse effects through infection and toxicity; higher concentrations can result in various microbial diseases. Moreover, they have a great influence on air quality in Beijing. In this study, a systematic survey on culturable airborne bacteria was carried out for 1 year at a slaughtering plant in Beijing. Bacterial samples were collected with FA-1 sampler for 3 min, three times each day, for three consecutive days of each month from three sampling sites using BIOLOG identification technology. Results showed that Gram-positive bacteria contributed 80%–85% and were much more prevalent than Gram-negative bacteria. Amongst 47 genera of bacteria, including 31 Gram-positive bacteria and 16 Gram-negative bacteria, Micrococcus, Staphylococcus, Bacillus, Corynebacterium, and Pseudomonas were dominant, and Micrococcus, which contributed 20%–30%, was the most dominant genus. The concentration of airborne bacteria was significantly higher in shed used to stay chicken waiting for slaughtering (SSC) and entrances to personnel and transport vehicles with products (EPV) than in green belt (GB). During the year, bacterial concentrations in summer and autumn were much higher than in winter and spring in SSC and EPV, and there were no significant variations in bacterial concentrations in GB. In different periods, a lower concentration of airborne bacteria was found at 13:00. PMID:23474646

Liang, Ruiping; Xiao, Peng; She, Ruiping; Han, Shiguo; Chang, Lingling; Zheng, Lingxiao

2013-01-01

183

Bacteria: Fossil Record  

NSDL National Science Digital Library

This description of the fossil record of bacteria focuses on one particular group of bacteria, the cyanobacteria or blue-green algae, which have left a fossil record that extends far back into the Precambrian. The oldest cyanobacteria-like fossils known are nearly 3.5 billion years old and are among the oldest fossils currently known. Cyanobacteria are larger than most bacteria and may secrete a thick cell wall. More importantly, cyanobacteria may form large layered structures, called stromatolites (if more or less dome-shaped) or oncolites (if round). The site also refers to pseudomorphs of pyrite and siderite, and a group of bacteria known as endolithic. Two links are available for more information. One provides information on the discovery of possible remains of bacteria-like organisms on a meteorite from Mars and the other has a research report on fossilized filamentous bacteria and other microbes, found in Cretaceous amber.

184

Limitations of beta-lactam therapy for infections caused by susceptible Gram-positive bacteria.  

PubMed

Penicillin and related beta-lactam agents have been the most widely used and most important antimicrobials in medical history, and remain the recommended therapy for many infectious diseases 85 years after the discovery of penicillin by Alexander Fleming. Yet the efficacy of these agents has been undermined by two factors - the emergence of clinically significant resistance to the antimicrobial activity of these agents, and clinical situations in which these drugs may be suboptimal (even though the bacterial pathogens are not "resistant" to the drugs). Observations in experimental infection models in animals (group A streptococcal myositis, pneumococcal meningitis and pneumonia, group B streptococcal sepsis) and in some cases clinical studies suggest that monotherapy with beta-lactam antibiotics may be inferior to treatment with other types of antibiotics, alone or in combination with beta-lactams - even in situations where the bacterial pathogens remain fully "susceptible" to beta-lactams in vitro. PMID:25124369

English, B Keith

2014-11-01

185

Resistance of Gram-positive bacteria to nisin is not determined by lipid II levels.  

PubMed

Lipid II is essential for nisin-mediated pore formation at nano-molar concentrations. We tested whether nisin resistance could result from different Lipid II levels, by comparing the maximal Lipid II pool in Micrococcus flavus (sensitive) and Listeria monocytogenes (relatively insensitive) and their nisin-resistant variants, with a newly developed method. No correlation was observed between the maximal Lipid II pool and nisin sensitivity, as was further corroborated by using spheroplasts of nisin-resistant and wild-type strains of M. flavus, which were equally sensitive to nisin. PMID:15451114

Kramer, Naomi E; Smid, Eddy J; Kok, Jan; de Kruijff, Ben; Kuipers, Oscar P; Breukink, Eefjan

2004-10-01

186

Antibacterial Activity of Glutathione-Coated Silver Nanoparticles against Gram Positive and Gram Negative Bacteria  

E-print Network

systems (iii) causing damage in respiration, (iv) perturbation of cellular growth, and (v) interaction. Interference in bacterial cell replication is observed for both cellular strains when exposed to GSH stabilized and other cell constituents (ii) causing K+ loss from the membrane, with disruption of cellular transport

187

The phage-related chromosomal islands of Gram-positive bacteria  

PubMed Central

The phage-related chromosomal islands (PRCIs) were first identified in Staphylococcus aureus as highly mobile, superantigen-encoding genetic elements known as the S. aureus pathogenicity islands (SaPIs). These elements are characterized by a specific set of phage-related functions that enable them to use the phage reproduction cycle for their own transduction and inhibit phage reproduction in the process. SaPIs produce many phage-like infectious particles; their streptococcal counterparts have a role in gene regulation but may not be infectious. These elements therefore represent phage satellites or parasites, not defective phages. In this Review, we discuss the shared genetic content of PRCIs, their life cycle and their ability to be transferred across large phylogenetic distances. PMID:20634809

Novick, Richard P.; Christie, Gail E.; Penadés, Jose R.

2012-01-01

188

Bacteria TMDL Projects  

E-print Network

of the projects are listed below. ? Peach CreekWater Quality Improvement Project ? Monitoring and Educational Programs Focused on Bacteria and Nutrient Runoff on Dairy Operations in the LeonWatershed ? Development of the Plum CreekWPP ? Impact of Proper... Star Healthy Streams * ? Environmental Management of Grazing Lands * *TWRI-managed projects More information on the initiative is available at www.tsswcb.state.tx.us/managementprogram/ initiatives/bacteria. Bacteria Projects Across the State...

Wythe, Kathy

2007-01-01

189

Introduction to Bacteria  

NSDL National Science Digital Library

This science site has students research how bacteria move, where they live, and how they reproduce; learn how bacteria can be helpful or harmful; and create a design illustrating what they have learned about bacteria. Included in the lesson plan are the objectives, needed materials and Web sites, procedures, discussion questions, evaluation, extensions, suggested reading, and vocabulary. Teachers can link to Teaching Tools to create custom worksheets, puzzles, and quizzes. A printable version of the lesson plan can be downloaded. The video Bacteria, Viruses and Allergies can be purchased and comprehension questions and answers can be downloaded.

DiscoverySchool.com

2007-12-12

190

Protection from Lethal Gram-Positive Infection by Macrophage Scavenger Receptor–Dependent Phagocytosis  

PubMed Central

Infections with gram-positive bacteria are a major cause of morbidity and mortality in humans. Opsonin-dependent phagocytosis plays a major role in protection against and recovery from gram-positive infections. Inborn and acquired defects in opsonin generation and/or recognition by phagocytes are associated with an increased susceptibility to bacterial infections. In contrast, the physiological significance of opsonin-independent phagocytosis is unknown. Type I and II class A scavenger receptors (SR-AI/II) recognize a variety of polyanions including bacterial cell wall products such as lipopolysaccharide (LPS) and lipoteichoic acid (LTA), suggesting a role for SR-AI/II in innate immunity to bacterial infections. Here, we show that SR-AI/II–deficient mice (MSR-A?/?) are more susceptible to intraperitoneal infection with a prototypic gram-positive pathogen, Staphylococcus aureus, than MSR-A+/+ control mice. MSR-A?/? mice display an impaired ability to clear bacteria from the site of infection despite normal killing of S. aureus by neutrophils and die as a result of disseminated infection. Opsonin-independent phagocytosis of gram-positive bacteria by MSR-A?/? macrophages is significantly decreased although their phagocytic machinery is intact. Peritoneal macrophages from control mice phagocytose a variety of gram-positive bacteria in an SR-AI/II–dependent manner. Our findings demonstrate that SR-AI/II mediate opsonin-independent phagocytosis of gram-positive bacteria, and provide the first evidence that opsonin-independent phagocytosis plays a critical role in host defense against bacterial infections in vivo. PMID:10620613

Thomas, Christian A.; Li, Yongmei; Kodama, Tatsuhiko; Suzuki, Hiroshi; Silverstein, Samuel C.; El Khoury, Joseph

2000-01-01

191

The effect of nutrient media water purity on LIBS based identification of bacteria  

Technology Transfer Automated Retrieval System (TEKTRAN)

Single pulse laser induced breakdown spectroscopy (LIBS) is used as the basis for discrimination between 3 genera of Gram-negative bacteria and 2 genera of gram-positive bacteria representing pathogenic threats commonly found in poultry processing rinse waters. Because LIBS-based discrimination reli...

192

Some Bacteria Are Beneficial!  

USGS Publications Warehouse

Most people would agree that bacteria usually spell trouble where the quality of drinking water is con cerned. However, recent studies conducted by the U.S. Geological Survey (USGS) under the National Water-Quality Assessment (NAWQA) program have shown that some bacteria can improve the quality of water.

McMahon, Peter B.

1995-01-01

193

Bacteria turn tiny gears  

SciTech Connect

Swarms of bacteria turn two 380-micron long gears, opening the possibility of building hybrid biological machines at the microscopic scale. Read more at Wired: http://www.wired.com/wiredscience/2009/12/bacterial-micro-machine/#more-15684 or Scientific American: http://www.scientificamerican.com/article.cfm?id=brownian-motion-bacteria

None

2009-01-01

194

Structural and physiological characteristics of some sheathed bacteria.  

PubMed

The fine structure and growth of two gram-negative and two gram-positive strains of sheathed bacteria, isolated from activated sludge, have been studied. Their anatomy is quite different from Sphaerotilus natans. The cells are rectangular, tightly joined together, non-motile and enclosed by a sheath which is thin in the gram-negative strains and rather electron-dense in the two larger gram positive strains. The four strains grow slowly and form pink filamentous flocs in liquid media. PMID:68709

Deinema, M H; Henstra, S; von Elgg, E W

1977-01-01

195

Penetration of bacteria into meat.  

PubMed Central

Bacteria are confined to the surface of meat during the logarithmic phase of growth. When proteolytic bacteria approach their maximum cell density, extracellular proteases secreted by the bacteria apparently break down the connective tissue between muscle fibers, allowing the bacteria to penetrate the meat. Non-proteolytic bacteria do not penetrate meat, even when grown in association with proteolytic species. Images PMID:406846

Gill, C O; Penney, N

1977-01-01

196

Clinical implications of nosocomial gram-positive bacteremia and superimposed antimicrobial resistance.  

PubMed

The coexistence of a pathogen population with an ever-increasing resistance to many antibiotics and a patient population characterized by increasingly complex clinical problems has contributed to an increase in the bloodstream infections associated with gram-positive bacteria. This serious therapeutic challenge has already been associated with an increase in infection-related morbidity and mortality, a prolongation of hospital stays, and an escalation of healthcare costs. Vancomycin resistance, long prevalent among the enterococci, has emerged in strains of Staphylococcus aureus. Several cases of infection caused by S. aureus strains with intermediate-level resistance to vancomycin (MIC=8 microg/mL) have recently been reported. As glycopeptide resistance accelerates among the gram-positive bacteria, so does the potential for adverse clinical consequences associated with bloodstream infections caused by these pathogens. The patients least able to tolerate the effects of uncontrolled bloodstream infections are also those at the highest risk for the development of infections caused by glycopeptide-resistant pathogens. In this at-risk population, a poor outcome may be anticipated if effective antibiotic therapy is unavailable. Appropriate rationing of vancomycin and other antimicrobial agents that increase the selection of antibiotic-resistant strains of gram-positive bacteria and the rapid development of novel antimicrobial agents with reliable gram-positive activity must be immediate priorities if the threat posed by glycopeptide-resistant gram-positive pathogens is to be countered. PMID:9684655

Linden, P K

1998-05-29

197

Efficacy of telavancin, a lipoglycopeptide antibiotic, in experimental models of Gram-positive infection.  

PubMed

Telavancin is a parenteral lipoglycopeptide antibiotic with a dual mechanism of action contributing to bactericidal activity against multidrug-resistant Gram-positive pathogens. It has been approved for the treatment of complicated skin and skin structure infections due to susceptible Gram-positive bacteria and hospital-acquired/ventilator-associated bacterial pneumonia due to Staphylococcus aureus when other alternatives are unsuitable. Telavancin has been demonstrated to be efficacious in multiple animal models of soft tissue, cardiac, systemic, lung, bone, brain and device-associated infections involving clinically relevant Gram-positive pathogens, including methicillin-resistant S. aureus, glycopeptide-intermediate S. aureus, heterogeneous vancomycin-intermediate S. aureus and daptomycin non-susceptible methicillin-resistant S. aureus. The AUC0-24h/MIC ratio is the primary pharmacodynamically-linked pharmacokinetic parameter. The preclinical data for telavancin supports further investigative clinical evaluation of its efficacy in additional serious infections caused by susceptible Gram-positive pathogens. PMID:25382700

Hegde, Sharath S; Janc, James W

2014-12-01

198

Recombinational DNA Repair in Bacteria  

E-print Network

Recombinational DNA Repair in Bacteria: Postreplication Kevin P Rice,University of Wisconsin Recombinational DNA repair represents the primary function for homologous DNA recombination in bacteria. Most of genetic diversity, primarily during conjugation, homologous DNA recombination in bacteria is now

Cox, Michael M.

199

Inactivation of biofilm bacteria.  

PubMed Central

The current project was developed to examine inactivation of biofilm bacteria and to characterize the interaction of biocides with pipe surfaces. Unattached bacteria were quite susceptible to the variety of disinfectants tested. Viable bacterial counts were reduced 99% by exposure to 0.08 mg of hypochlorous acid (pH 7.0) per liter (1 to 2 degrees C) for 1 min. For monochloramine, 94 mg/liter was required to kill 99% of the bacteria within 1 min. These results were consistent with those found by other investigators. Biofilm bacteria grown on the surfaces of granular activated carbon particles, metal coupons, or glass microscope slides were 150 to more than 3,000 times more resistant to hypochlorous acid (free chlorine, pH 7.0) than were unattached cells. In contrast, resistance of biofilm bacteria to monochloramine disinfection ranged from 2- to 100-fold more than that of unattached cells. The results suggested that, relative to inactivation of unattached bacteria, monochloramine was better able to penetrate and kill biofilm bacteria than free chlorine. For free chlorine, the data indicated that transport of the disinfectant into the biofilm was a major rate-limiting factor. Because of this phenomenon, increasing the level of free chlorine did not increase disinfection efficiency. Experiments where equal weights of disinfectants were used suggested that the greater penetrating power of monochloramine compensated for its limited disinfection activity. These studies showed that monochloramine was as effective as free chlorine for inactivation of biofilm bacteria. The research provides important insights into strategies for control of biofilm bacteria. Images PMID:2849380

LeChevallier, M W; Cawthon, C D; Lee, R G

1988-01-01

200

Inactivation of Gram-positive biofilms by low-temperature plasma jet at atmospheric pressure  

Microsoft Academic Search

This work is devoted to the evaluation of the efficiency of a new low-temperature plasma jet driven in ambient air by a dc-corona discharge to inactivate adherent cells and biofilms of Gram-positive bacteria. The selected microorganisms were lactic acid bacteria, a Weissella confusa strain which has the particularity to excrete a polysaccharide polymer (dextran) when sucrose is present. Both adherent

F Marchal; H Robert; N Merbahi; C Fontagné-Faucher; M Yousfi; C E Romain; O Eichwald; C Rondel; B Gabriel

2012-01-01

201

Indicator For Pseudomonas Bacteria  

NASA Technical Reports Server (NTRS)

Characteristic protein extracted and detected. Natural protein marker found in Pseudomonas bacteria. Azurin, protein containing copper readily extracted, purified, and used to prepare antibodies. Possible to develop simple, fast, and accurate test for marker carried out in doctor's office.

Margalit, Ruth

1990-01-01

202

Cultivation Media for Bacteria  

NSDL National Science Digital Library

Common bacteriological culture media (tryptic soy agar, chocolate agar, Thayer-Martin agar, MacConkey agar, eosin-methylene blue agar, hektoen agar, mannitol salt agar, and sheep blood agar) are shown uninoculated and inoculated with bacteria.

American Society For Microbiology

2009-12-08

203

Bacteria in shear flow  

E-print Network

Bacteria are ubiquitous and play a critical role in many contexts. Their environment is nearly always dynamic due to the prevalence of fluid flow: creeping flow in soil, highly sheared flow in bodily conduits, and turbulent ...

Marcos, Ph.D. Massachusetts Institute of Technology

2011-01-01

204

Phosphatidic acid synthesis in bacteria.  

PubMed

Membrane phospholipid synthesis is a vital facet of bacterial physiology. Although the spectrum of phospholipid headgroup structures produced by bacteria is large, the key precursor to all of these molecules is phosphatidic acid (PtdOH). Glycerol-3-phosphate derived from the glycolysis via glycerol-phosphate synthase is the universal source for the glycerol backbone of PtdOH. There are two distinct families of enzymes responsible for the acylation of the 1-position of glycerol-3-phosphate. The PlsB acyltransferase was discovered in Escherichia coli, and homologs are present in many eukaryotes. This protein family primarily uses acyl-acyl carrier protein (ACP) endproducts of fatty acid synthesis as acyl donors, but may also use acyl-CoA derived from exogenous fatty acids. The second protein family, PlsY, is more widely distributed in bacteria and utilizes the unique acyl donor, acyl-phosphate, which is produced from acyl-ACP by the enzyme PlsX. The acylation of the 2-position is carried out by members of the PlsC protein family. All PlsCs use acyl-ACP as the acyl donor, although the PlsCs of the ?-proteobacteria also may use acyl-CoA. Phospholipid headgroups are precursors in the biosynthesis of other membrane-associated molecules and the diacylglycerol product of these reactions is converted to PtdOH by one of two distinct families of lipid kinases. The central importance of the de novo and recycling pathways to PtdOH in cell physiology suggest that these enzymes are suitable targets for the development of antibacterial therapeutics in Gram-positive pathogens. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism. PMID:22981714

Yao, Jiangwei; Rock, Charles O

2013-03-01

205

Aerobic Anoxygenic Phototrophic Bacteria  

PubMed Central

The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the ?-1, ?-3, and ?-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

Yurkov, Vladimir V.; Beatty, J. Thomas

1998-01-01

206

Evaluation of the antibacterial potential of Petroselinum crispum and Rosmarinus officinalis against bacteria that cause urinary tract infections  

PubMed Central

In this study we evaluated the antibacterial activity of the crude hydroalcoholic extracts, fractions, and compounds of two plant species, namely Rosmarinus officinalis and Petroselinum crispum, against the bacteria that cause urinary tract infection. The microdilution method was used for determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The crude hydroalcoholic extract of R. officinalis displayed in vitro activity against Gram-positive bacteria, with satisfactory MBC for the clinical isolate S. saprophyticus. The fractions and the pure compound rosmarinic acid did not furnish promising results for Gram-negative bacteria, whereas fractions 2, 3, and 4 gave encouraging results for Gram-positive bacteria and acted as bactericide against S. epidermidis as well as E. faecalis (ATCC 29212) and its clinical isolate. R. officinalis led to promising results in the case of Gram-positive bacteria, resulting in a considerable interest in the development of reliable alternatives for the treatment of urinary infections. PMID:24516424

Petrolini, Fernanda Villas Boas; Lucarini, Rodrigo; de Souza, Maria Gorete Mendes; Pires, Regina Helena; Cunha, Wilson Roberto; Martins, Carlos Henrique Gomes

2013-01-01

207

PVC biodeterioration and DEHP leaching by DEHP-degrading bacteria  

PubMed Central

Newly isolated, not previously reported, di-(2-ethylhexyl) phthalate (DEHP)-degraders were augmented to assess their role in polyvinyl chloride (PVC) shower curtain deterioration and DEHP leaching. The biofilms that developed on the surfaces of the bioaugmented shower curtains with Gram-positive strains LHM1 and LHM2 were thicker than those of the biostimulated and Gram-negative strain LHM3-augmented shower curtains. The first derivative thermogravimetric (DTG) peaks of the bioaugmented shower curtains with the Gram-positive bacteria were observed at ~287°C, whereas the control and Gram-negative strain LHM3-augmented shower curtains were detected at ~283°C. This slight delay in the first DTG peak temperature is indicative of lower plasticizer concentrations in the shower curtains that were bioaugmented with Gram positive bacteria. Despite bioaugmentation with DEHP-degraders, aqueous solutions of the bioaugmentation reactors were not DEHP-free due probably to the presence of co-solutes that must have supported microbial growth. Generally, the bioaugmented reactors with the Gram-positive strains LHM1 and LHM2 had greater aqueous DEHP concentrations in the first-half (<3 wk) of the biodeterioration experiment than the biostimulated and strain LHM3-augmented reactors. Therefore, strains LHM1 and LHM2 may play an important role in DEHP leaching to the environment and PVC biodeterioration. PMID:22736894

Latorre, Isomar; Hwang, Sangchul; Sevillano, Maria; Montalvo-Rodriguez, Rafael

2012-01-01

208

Structural biology of gram-positive bacterial adhesins  

PubMed Central

The structural biology of Gram-positive cell surface adhesins is an emerging field of research, whereas Gram-negative pilus assembly and anchoring have been extensively investigated and are well understood. Gram-positive surface proteins known as MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) and individual proteins that assemble into long, hair-like organelles known as pili have similar features at the primary sequence level as well as at the tertiary structural level. Some of these conserved features are essential for their transportation from the cytoplasm and for cell wall anchoring. More importantly, the MSCRAMMs and the individual pilins are assembled with building blocks that are variants of structural modules used for human immunoglobulins. MSCRAMMs target the host's extracellular matrix proteins, such as collagen, fibrinogen, and fibronectin, and they have received considerable attention from structural biologists in the last decade, who have primarily been interested in understanding their interactions with host tissue. The recent focus is on the newly discovered pili of Gram-positive bacteria, and in this review, we highlight the advances in understanding of the individual pilus constituents and their associations and stress the similarities between the individual pilins and surface proteins. PMID:21404359

Vengadesan, Krishnan; Narayana, Sthanam V L

2011-01-01

209

Ice-Nucleating Bacteria  

NASA Astrophysics Data System (ADS)

Since the discovery of ice-nucleating bacteria in 1974 by Maki et al., a large number of studies on the biological characteristics, ice-nucleating substance, ice nucleation gene and frost damage etc. of the bacteria have been carried out. Ice-nucleating bacteria can cause the freezing of water at relatively warm temperature (-2.3°C). Tween 20 was good substrates for ice-nucleating activity of Pseudomonas fluorescens KUIN-1. Major fatty acids of Isolate (Pseudomonas fluorescens) W-11 grown at 30°C were palmitic, cis-9-hexadecenoic and cis-11-octadecenoic which amounted to 90% of the total fatty acids. Sequence analysis shows that an ice nucleation gene from Pseudomonas fluorescens is related to the gene of Pseudomonas syringae.

Obata, Hitoshi

210

Dispersal of non-sporeforming anaerobic bacteria from the skin.  

PubMed

Dispersal of non-sporeforming anaerobic bacteria was studied. Skin samples were taken from the subjects, and dispersed from different parts of the body was examined. The number of anaerobic bacteria dispersed was not correlated to their density on the surface of skin area exposed. The highest density of anaerobic bacteria on the skin was found in the face and upper trunk, but the highest yield of anaerobic bacteria dispersed came from the lower trunk. The dominant anaerobic bacteria dispersed were Propionibacterium acnes, but Propionibacterium avidum, Propionibacterium granulosum and Gram-positive cocci were also isolated from the dispersal samples. Peptococcus magnus was the most common coccus isolated. For the less frequently isolated bacteria, the best correlation was found between the perineal flora and airborne bacteria. A comparison was also made of bacterial dispersal by naked and dressed subjects. The dispersal of both aerobic and anaerobic bacteria was higher when the subjects were dressed in conventional operating theatre cotton clothing than when they were naked. The increased dispersal of anaerobic bacteria when the subjects were dressed was mainly due to increased dispersal of Propionibacterium sp. PMID:6806353

Benediktsdóttir, E; Hambraeus, A

1982-06-01

211

Non-thermal plasma mills bacteria: Scanning electron microscopy observations  

NASA Astrophysics Data System (ADS)

Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin-stained rat skin sections from plasma-treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy.

Lunov, O.; Churpita, O.; Zablotskii, V.; Deyneka, I. G.; Meshkovskii, I. K.; Jäger, A.; Syková, E.; Kubinová, Š.; Dejneka, A.

2015-02-01

212

Glowing Bacteria: Transformation Efficiency  

E-print Network

1 Glowing Bacteria: Transformation Efficiency Purpose: To determine how well your E. coli cells took up and expressed GFP after transformation. Background: Transformation efficiency is a quantitative)______ (Fraction of DNA spread on plate) = ______ µg plasmid DNA spread on plate #12;2 5. Transformation efficiency

Rose, Michael R.

213

Beneficial plant bacteria  

Microsoft Academic Search

The recognition of plant growth?promoting rhizobacteria (PGPR), a group of beneficial plant bacteria, as potentially useful for stimulating plant growth and increasing crop yields has evolved over the past several years to where today researchers are able to repeatedly use them successfully in field experiments. Increased growth and yields of potato, sugar beet, and radish have been reported. The most

Thomas J. Burr; Anthony Caesar; M. N. Schrolh

1984-01-01

214

Sexual isolation in bacteria  

Microsoft Academic Search

Bacteria exchange genes rarely but are promiscuous in the choice of their genetic partners. Inter-specific recombination has the advantage of increasing genetic diversity and promoting dissemination of novel adaptations, but suffers from the negative effect of importing potentially harmful alleles from incompatible genomes. Bacterial species experience a degree of 'sexual isolation' from genetically divergent organisms ^ recombination occurs more frequently

Jacek Majewski

2001-01-01

215

Bacteria-surface interactions  

PubMed Central

The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field. PMID:23930134

Tuson, Hannah H.; Weibel, Douglas B.

2013-01-01

216

Thermophilic bacteria from wool  

Microsoft Academic Search

Twenty-one samples of wool removed from pelts either by the “pie” or “slipemaster” process were obtained from meat works throughout New Zealand. The number of mesophilic and thermophilic bacteria on the samples was determined by the plate count method. The numbers of thermophiles varied from less than 102 to 1.9 × 10\\/g. Six isolates were obtained for final study; these

A. P. Mulcock; Philippa E. Horn

1965-01-01

217

Photobiology of Bacteria  

Microsoft Academic Search

The field of photobiology is concerned with the interactions between light and living matter. For Bacteria this interaction serves three recognisable physiological functions: provision of energy, protection against excess radiation and signalling (for motility and gene expression). The chemical structure of the primary light-absorbing components in biology (the chromophores of photoactive proteins) is surprisingly simple: tetrapyrroles, polyenes and derivatised aromats

K. J. Hellingwerf; W. Crielaard; W. D. Hoff; H. C. P. Matthijs; L. R. Mur; B. J. Rotterdam

1994-01-01

218

Aquatic Bacteria Samples  

USGS Multimedia Gallery

On April 20, 2010, the BP Deepwater Horizon drilling platform collapsed and sank in the Gulf of Mexico, causing one of the largest oil spills in history. One of the big dilemmas in responding to the oil spil is how to clean up the oil itself. One way currently under research is to use bacteria that ...

219

Susceptibility and resistance of ruminal bacteria to antimicrobial feed additives.  

PubMed Central

Susceptibility and resistance of ruminal bacterial species to avoparcin, narasin, salinomycin, thiopeptin, tylosin, virginiamycin, and two new ionophore antibiotics, RO22-6924/004 and RO21-6447/009, were determined. Generally, antimicrobial compounds were inhibitory to gram-positive bacteria and those bacteria that have gram-positive-like cell wall structure. MICs ranged from 0.09 to 24.0 micrograms/ml. Gram-negative bacteria were resistant at the highest concentration tested (48.0 micrograms/ml). On the basis of their fermentation products, ruminal bacteria that produce lactic acid, butyric acid, formic acid, or hydrogen were susceptible and bacteria that produce succinic acid or ferment lactic acid were resistant to the antimicrobial compounds. Selenomonas ruminantium was the only major lactic acid-producing bacteria resistant to all the antimicrobial compounds tested. Avoparcin and tylosin appeared to be less inhibitory (MIC greater than 6.0 micrograms/ml) than the other compounds to the two major lactic acid-producing bacteria, Streptococcus bovis and Lactobacillus sp. Ionophore compounds seemed to be more inhibitory (MIC, 0.09 to 1.50 micrograms/ml) than nonionophore compounds (MIC, 0.75 to 12.0 micrograms/ml) to the major butyric acid-producing bacteria. Treponema bryantii, an anaerobic rumen spirochete, was less sensitive to virginiamycin than to the other antimicrobial compounds. Ionophore compounds were generally bacteriostatic, and nonionophore compounds were bactericidal. The specific growth rate of Bacteroides ruminicola was reduced by all the antimicrobial compounds except avoparcin. The antibacterial spectra of the feed additives were remarkably similar, and it appears that MICs may not be good indicators of the potency of the compounds in altering ruminal fermentation characteristics. PMID:3116929

Nagaraja, T G; Taylor, M B

1987-01-01

220

Characterization of viable bacteria from Siberian permafrost by 16S rDNA sequencing  

NASA Technical Reports Server (NTRS)

Viable bacteria were found in permafrost core samples from the Kolyma-Indigirka lowland of northeast Siberia. The samples were obtained at different depths; the deepest was about 3 million years old. The average temperature of the permafrost is -10 degrees C. Twenty-nine bacterial isolates were characterized by 16S rDNA sequencing and phylogenetic analysis, cell morphology, Gram staining, endospore formation, and growth at 30 degrees C. The majority of the bacterial isolates were rod shaped and grew well at 30 degrees C; but two of them did not grow at or above 28 degrees C, and had optimum growth temperatures around 20 degrees C. Thirty percent of the isolates could form endospores. Phylogenetic analysis revealed that the isolates fell into four categories: high-GC Gram-positive bacteria, beta-proteobacteria, gamma-proteobacteria, and low-GC Gram-positive bacteria. Most high-GC Gram-positive bacteria and beta-proteobacteria, and all gamma-proteobacteria, came from samples with an estimated age of 1.8-3.0 million years (Olyor suite). Most low-GC Gram-positive bacteria came from samples with an estimated age of 5,000-8,000 years (Alas suite).

Shi, T.; Reeves, R. H.; Gilichinsky, D. A.; Friedmann, E. I.

1997-01-01

221

Cell wall structure and function in lactic acid bacteria  

PubMed Central

The cell wall of Gram-positive bacteria is a complex assemblage of glycopolymers and proteins. It consists of a thick peptidoglycan sacculus that surrounds the cytoplasmic membrane and that is decorated with teichoic acids, polysaccharides, and proteins. It plays a major role in bacterial physiology since it maintains cell shape and integrity during growth and division; in addition, it acts as the interface between the bacterium and its environment. Lactic acid bacteria (LAB) are traditionally and widely used to ferment food, and they are also the subject of more and more research because of their potential health-related benefits. It is now recognized that understanding the composition, structure, and properties of LAB cell walls is a crucial part of developing technological and health applications using these bacteria. In this review, we examine the different components of the Gram-positive cell wall: peptidoglycan, teichoic acids, polysaccharides, and proteins. We present recent findings regarding the structure and function of these complex compounds, results that have emerged thanks to the tandem development of structural analysis and whole genome sequencing. Although general structures and biosynthesis pathways are conserved among Gram-positive bacteria, studies have revealed that LAB cell walls demonstrate unique properties; these studies have yielded some notable, fundamental, and novel findings. Given the potential of this research to contribute to future applied strategies, in our discussion of the role played by cell wall components in LAB physiology, we pay special attention to the mechanisms controlling bacterial autolysis, bacterial sensitivity to bacteriophages and the mechanisms underlying interactions between probiotic bacteria and their hosts. PMID:25186919

2014-01-01

222

Invasion of dentinal tubules by oral bacteria.  

PubMed

Bacterial invasion of dentinal tubules commonly occurs when dentin is exposed following a breach in the integrity of the overlying enamel or cementum. Bacterial products diffuse through the dentinal tubule toward the pulp and evoke inflammatory changes in the pulpo-dentin complex. These may eliminate the bacterial insult and block the route of infection. Unchecked, invasion results in pulpitis and pulp necrosis, infection of the root canal system, and periapical disease. While several hundred bacterial species are known to inhabit the oral cavity, a relatively small and select group of bacteria is involved in the invasion of dentinal tubules and subsequent infection of the root canal space. Gram-positive organisms dominate the tubule microflora in both carious and non-carious dentin. The relatively high numbers of obligate anaerobes present-such as Eubacterium spp., Propionibacterium spp., Bifidobacterium spp., Peptostreptococcus micros, and Veillonella spp.-suggest that the environment favors growth of these bacteria. Gram-negative obligate anaerobic rods, e.g., Porphyromonas spp., are less frequently recovered. Streptococci are among the most commonly identified bacteria that invade dentin. Recent evidence suggests that streptococci may recognize components present within dentinal tubules, such as collagen type I, which stimulate bacterial adhesion and intra-tubular growth. Specific interactions of other oral bacteria with invading streptococci may then facilitate the invasion of dentin by select bacterial groupings. An understanding the mechanisms involved in dentinal tubule invasion by bacteria should allow for the development of new control strategies, such as inhibitory compounds incorporated into oral health care products or dental materials, which would assist in the practice of endodontics. PMID:12097359

Love, R M; Jenkinson, H F

2002-01-01

223

Multitasking SecB chaperones in bacteria  

PubMed Central

Protein export in bacteria is facilitated by the canonical SecB chaperone, which binds to unfolded precursor proteins, maintains them in a translocation competent state and specifically cooperates with the translocase motor SecA to ensure their proper targeting to the Sec translocon at the cytoplasmic membrane. Besides its key contribution to the Sec pathway, SecB chaperone tasking is critical for the secretion of the Sec-independent heme-binding protein HasA and actively contributes to the cellular network of chaperones that control general proteostasis in Escherichia coli, as judged by the significant interplay found between SecB and the trigger factor, DnaK and GroEL chaperones. Although SecB is mainly a proteobacterial chaperone associated with the presence of an outer membrane and outer membrane proteins, secB-like genes are also found in Gram-positive bacteria as well as in certain phages and plasmids, thus suggesting alternative functions. In addition, a SecB-like protein is also present in the major human pathogen Mycobacterium tuberculosis where it specifically controls a stress-responsive toxin–antitoxin system. This review focuses on such very diverse chaperone functions of SecB, both in E. coli and in other unrelated bacteria. PMID:25538690

Sala, Ambre; Bordes, Patricia; Genevaux, Pierre

2014-01-01

224

Stabilizing isopeptide bonds revealed in gram-positive bacterial pilus structure.  

PubMed

Many bacterial pathogens have long, slender pili through which they adhere to host cells. The crystal structure of the major pilin subunit from the Gram-positive human pathogen Streptococcus pyogenes at 2.2 angstroms resolution reveals an extended structure comprising two all-beta domains. The molecules associate in columns through the crystal, with each carboxyl terminus adjacent to a conserved lysine of the next molecule. This lysine forms the isopeptide bonds that link the subunits in native pili, validating the relevance of the crystal assembly. Each subunit contains two lysine-asparagine isopeptide bonds generated by an intramolecular reaction, and we find evidence for similar isopeptide bonds in other cell surface proteins of Gram-positive bacteria. The present structure explains the strength and stability of such Gram-positive pili and could facilitate vaccine development. PMID:18063798

Kang, Hae Joo; Coulibaly, Fasséli; Clow, Fiona; Proft, Thomas; Baker, Edward N

2007-12-01

225

Three Activities: Bacteria Study, Micro Study, and Bacteria Killers  

NSDL National Science Digital Library

This resource provides a problem-based activity on risk assessment of environmental health issues. The lesson consists of three related activities: Bacteria Study, Micro Study and Bacteria Killers. "Bacteria Study" gives students hands-on experience with the concepts of epidemiology. "Micro Study" has students sketch, observe, and compare different types of bacteria that can grow in moist conditions. "Bacteria Killers" has students determine what kills bateria, especially in common household products. Detailed instructions are provided for each activity. This resource is free to download. Users must first create a login with ATEEC's website to access the file.

226

News and Research Good Bacteria  

E-print Network

News and Research Good Bacteria Part 2 Article 13 Click here for Probiotics Basics Cooperation Is A No-brainer For Symbiotic Bacteria 9-4-2003 Humans may learn cooperation in kindergarten, but what about bacteria, whose behavior is preprogrammed by their DNA? Some legume plants, which rely

West, Stuart

227

Antimicrobial Action of Some Citrus Fruit Oils on Selected Food-Borne Bacteria  

PubMed Central

The antimicrobial properties of essential oils, terpineol, and orange oil, in particular, varied according to the type of bacteria tested. Terpineol and other terpeneless fractions of citrus oils appeared to have greater inhibitory effect on food-borne bacteria than the other citrus oils or derivatives. Gram-positive bacteria were, in general, more sensitive to essential oils than gram-negative bacteria. Terpineol extended the shelf life of commercially pasteurized skim milk, low-fat milk, and whole milk for more than 56 days at 4 C. Orange oil extended the shelf life of skim milk and low-fat milk for the same period. PMID:4905947

Dabbah, Roger; Edwards, V. M.; Moats, W. A.

1970-01-01

228

Identification, classification, and clinical relevance of catalase-negative, gram-positive cocci, excluding the streptococci and enterococci.  

PubMed Central

Several new genera and species of gram-positive, catalase-negative cocci that can cause infections in humans have been described. Although these bacteria were isolated in the clinical laboratory, they were considered nonpathogenic culture contaminants and were not thought to be the cause of any diseases. Isolation of pure cultures of these bacteria from normally sterile sites has led to the conclusion that these bacteria can be an infrequent cause of infection. This review describes the new bacteria and the procedures useful for clinical laboratories to aid in their identification. The clinical relevance and our experience with the various genera and species are reviewed and discussed. PMID:8665466

Facklam, R; Elliott, J A

1995-01-01

229

Exopolysaccharides from marine bacteria  

NASA Astrophysics Data System (ADS)

Microbial polysaccharides represent a class of important products of growing interest for many sectors of industry. In recent years, there has been a growing interest in isolating new exopolysaccharides (EPSs)-producing bacteria from marine environments, particularly from various extreme marine environments. Many new marine microbial EPSs with novel chemical compositions, properties and structures have been found to have potential applications in fields such as adhesives, textiles, Pharmaceuticals and medicine for anti-cancer, food additives, oil recovery and metal removal in mining and industrial waste treatments, etc This paper gives a brief summary of the information about the EPSs produced by marine bacteria, including their chemical compositions, properties and structures, together with their potential applications in industry.

Chi, Zhenming; Fang, Yan

2005-01-01

230

Lipoprotein sorting in bacteria.  

PubMed

Bacterial lipoproteins are synthesized as precursors in the cytoplasm and processed into mature forms on the cytoplasmic membrane. A lipid moiety attached to the N terminus anchors these proteins to the membrane surface. Many bacteria are predicted to express more than 100 lipoproteins, which play diverse functions on the cell surface. The Lol system, composed of five proteins, catalyzes the localization of Escherichia coli lipoproteins to the outer membrane. Some lipoproteins play vital roles in the sorting of other lipoproteins, lipopolysaccharides, and ?-barrel proteins to the outer membrane. On the basis of results from biochemical, genetic, and structural studies, we discuss the biogenesis of lipoproteins in bacteria, their importance in cellular functions, and the molecular mechanisms underlying efficient sorting of hydrophobic lipoproteins to the outer membrane through the hydrophilic periplasm. PMID:21663440

Okuda, Suguru; Tokuda, Hajime

2011-01-01

231

Bacteria, food, and cancer  

PubMed Central

Gut microbes are essential components of the human organism—helping us metabolize food into energy, produce micronutrients, and shape our immune systems. Having a particular pattern of gut microbes is also increasingly being linked to medical conditions including obesity, inflammatory bowel disease, and diabetes. Recent studies now indicate that our resident intestinal bacteria may also play a critical role in determining one's risk of developing cancer, ranging from protection against cancer to promoting its initiation and progression. Gut bacteria are greatly influenced by diet and in this review we explore evidence that they may be the missing piece that explains how dietary intake influences cancer risk, and discuss possible prevention and treatment strategies. PMID:21876723

Rooks, Michelle G.

2011-01-01

232

Reanimation of Ancient Bacteria  

SciTech Connect

Recent highly publicized experiments conducted on salt crystals taken from the Permian Salado Formation in Southeastern New Mexico have shown that some ancient crystals contain viable microorganisms trapped within fluid inclusions. Stringent geological and microbiological selection criteria were used to select crystals and conduct all sampling. This talk will focus on how each of these lines of data support the conclusion that such isolated bacteria are as old as the rock in which they are trapped. In this case, the isolated microbes are salt tolerant bacilli that grow best in media containing 8% NaCl, and respond to concentrated brines by forming spores. One of the organisms is phylogenetically related to several bacilli, but does have several unique characteristics. This talk will trace the interdisciplinary data and procedures supporting these discoveries, and describe the various isolated bacteria.

Russell Vreeland

2009-01-09

233

Bacteria: More Than Pathogens  

NSDL National Science Digital Library

This ActionBioscience lesson plan has students explore the many roles of bacteria, harmful and beneficial. A detailed article written for ActionBioscience by a microbiologist provides background information, which is followed by discussion questions and educational activities designed for middle school to undergraduate biology courses. The Web site also provides carefully selected links for further exploring the topic, including useful sites for student research projects.

Wassenaar, Trudy M.

234

Glacial Lake Hides Bacteria  

NSDL National Science Digital Library

This article highlights the published work of a geomicrobiology research team led by Eric Gaidos from the University of Hawaii and Brian Lanoil, from the University of California, Riverside. This group reports the identification of bacteria from an Icelandic sub-glacial lake, and how the collection and description of these microorganisms immured within glacial ice and sub-surface water serve as a model in the search for extra-terrestrial life.

2010-03-01

235

Bacteria in Confined Spaces  

NASA Astrophysics Data System (ADS)

Bacterial cells can display differentiation between several developmental pathways, from planktonic to matrix-producing, depending upon the colony conditions. We study the confinement of bacteria in hydrogels as well as in liquid-liquid double emulsion droplets and observe the growth and morphology of these colonies as a function of time and environment. Our results can give insight into the behavior of bacterial colonies in confined spaces that can have applications in the areas of food science, cosmetics, and medicine.

Wilking, Connie; Weitz, David

2010-03-01

236

Glacial lake hides bacteria  

NSDL National Science Digital Library

This article highlights the published work of a geomicrobiology research team led by Eric Gaidos from the University of Hawaii and Brian Lanoil, from the University of California, Riverside. This group reports the identification of bacteria from an Icelandic sub-glacial lake, and how the collection and description of these microorganisms immured within glacial ice and sub-surface water serve as a model in the search for extra-terrestrial life.

Mark Peplow

237

Antibiotic Resistant Bacteria  

NSDL National Science Digital Library

This week's Topic In Depth is about antibiotic resistant bacteria.The first site is a recent news report from BBC news (1) that describes some recent research on resistant strains of two "of the world's most dangerous bacteria. Next is a Centers for Disease Control (CDC) page (2) with a brief background on antibiotic resistance and how to prevent it. A much more in-depth report is provided by the Select Committee on Science and Technology of the British House of Lords (3). There has been some public concern over the use of antibiotic resistant bacteria strains as markers in genetically modified food crops. The next two resources present information specific to this topic. The first is from the European Federation of Biotechnology (4), and the second is a shorter report from the Council for Biotechnology Information (5). The Alliance for the Prudent Use of Antibiotics (6) has a consumer and patient information section that explains what individuals can do to help prevent the problem from increasing. Readers who need a brief primer on antibiotics may appreciate this Web site from the University of Edinburgh (7). The last site is a "bugs in the news" feature from the University of Kansas (8), which is an easy-to-read explanation of "what the heck" antibiotic resistance is.

Lee, Amy.

2002-01-01

238

Effects of oral commensal and pathogenic bacteria on human dendritic cells  

PubMed Central

Background/aims The oral cavity harbors a diverse and complex microbial community. Bacteria accumulate on both the hard and soft oral tissues in sessile biofilms and engage the host in an intricate cellular dialog, which normally constrains the bacteria to a state of commensal harmony. Dendritic cells (DCs) are likely to balance tolerance and active immunity to commensal microorganisms as part of chronic inflammatory responses. While the role played by DCs in maintaining intestinal homeostasis has been investigated extensively, relatively little is known about DC responses to oral bacteria. Methods In this study, we pulsed human monocyte-derived immature DCs (iDCs) with cell wall extracts from pathogenic and commensal gram-positive or gram-negative oral bacteria. Results Although all bacterial extracts tested induced iDCs to mature and produce cytokines/chemokines including interleukin-12p40, tumor necrosis factor-?, and monocyte chemoattractant protein-1 (MCP-1), the most important factor for programming DCs by oral bacteria was whether they were gram-positive or gram-negative, not whether they were commensal or pathogenic. In general, gram-negative oral bacteria, except for periodontopathic Porphyromonas gingivalis, stimulated DC maturation and cytokine production at lower concentrations than gram-positive oral bacteria. The threshold of bacteria needed to stimulate chemokine production was 100-fold to 1000-fold lower than that needed to induce cytokines. In addition, very low doses of oral commensal bacteria triggered monocytes to migrate toward DC-derived MCP-1. Conclusion Oral commensal and pathogenic bacteria do not differ qualitatively in how they program DCs. DC-derived MCP-1 induced in response to oral commensal bacteria may play a role, at least in part, in the maintenance of oral tissue integrity by attracting monocytes. PMID:19239635

Chino, T.; Santer, D. M.; Giordano, D.; Chen, C.; Li, C.; Chen, C.-H.; Darveau, R. P.; Clark, E. A.

2009-01-01

239

Pepsin homologues in bacteria  

PubMed Central

Background Peptidase family A1, to which pepsin belongs, had been assumed to be restricted to eukaryotes. The tertiary structure of pepsin shows two lobes with similar folds and it has been suggested that the gene has arisen from an ancient duplication and fusion event. The only sequence similarity between the lobes is restricted to the motif around the active site aspartate and a hydrophobic-hydrophobic-Gly motif. Together, these contribute to an essential structural feature known as a psi-loop. There is one such psi-loop in each lobe, and so each lobe presents an active Asp. The human immunodeficiency virus peptidase, retropepsin, from peptidase family A2 also has a similar fold but consists of one lobe only and has to dimerize to be active. All known members of family A1 show the bilobed structure, but it is unclear if the ancestor of family A1 was similar to an A2 peptidase, or if the ancestral retropepsin was derived from a half-pepsin gene. The presence of a pepsin homologue in a prokaryote might give insights into the evolution of the pepsin family. Results Homologues of the aspartic peptidase pepsin have been found in the completed genomic sequences from seven species of bacteria. The bacterial homologues, unlike those from eukaryotes, do not possess signal peptides, and would therefore be intracellular acting at neutral pH. The bacterial homologues have Thr218 replaced by Asp, a change which in renin has been shown to confer activity at neutral pH. No pepsin homologues could be detected in any archaean genome. Conclusion The peptidase family A1 is found in some species of bacteria as well as eukaryotes. The bacterial homologues fall into two groups, one from oceanic bacteria and one from plant symbionts. The bacterial homologues are all predicted to be intracellular proteins, unlike the eukaryotic enzymes. The bacterial homologues are bilobed like pepsin, implying that if no horizontal gene transfer has occurred the duplication and fusion event might be very ancient indeed, preceding the divergence of bacteria and eukaryotes. It is unclear whether all the bacterial homologues are derived from horizontal gene transfer, but those from the plant symbionts probably are. The homologues from oceanic bacteria are most closely related to memapsins (or BACE-1 and BACE-2), but are so divergent that they are close to the root of the phylogenetic tree and to the division of the A1 family into two subfamilies. PMID:19758436

Rawlings, Neil D; Bateman, Alex

2009-01-01

240

The Drosophila immune response against Gram-negative bacteria is mediated by a peptidoglycan recognition protein  

Microsoft Academic Search

The antimicrobial defence of Drosophila relies largely on the challenge-induced synthesis of an array of potent antimicrobial peptides by the fat body. The defence against Gram-positive bacteria and natural fungal infections is mediated by the Toll signalling pathway, whereas defence against Gram-negative bacteria is dependent on the Immune deficiency (IMD) pathway. Loss-of-function mutations in either pathway reduce the resistance to

Marie Gottar; Vanessa Gobert; Tatiana Michel; Marcia Belvin; Geoffrey Duyk; Jules A. Hoffmann; Dominique Ferrandon; Julien Royet

2002-01-01

241

Comparative In Vitro Activities of Gemifloxacin, Other Quinolones, and Nonquinolone Antimicrobials against Obligately Anaerobic Bacteria  

Microsoft Academic Search

Gemifloxacin mesylate (SB 265805) is a fluoroquinolone with a novel oxime-derivatized pyrrolidine substituent at posi- tion C7 which is thought to confer the enhanced activity against gram-positive bacteria (11). A limited number of stud- ies have focused on its potential activity against anaerobic bacteria, demonstrating variable susceptibility patterns of the different anaerobic genera (3, 4, 7-10, 12). To further evaluate

NIELS KLEINKAUF; GRIT ACKERMANN; REINER SCHAUMANN; ARNE C. RODLOFF

2001-01-01

242

Isolation and Characterization of Endophytic Colonizing Bacteria from Agronomic Crops and Prairie Plants  

Microsoft Academic Search

Endophytic bacteria reside within plant hosts without causing disease symptoms. In this study, 853 endophytic strains were isolated from aerial tissues of four agronomic crop species and 27 prairie plant species. We determined several phenotypic properties and found approximately equal numbers of gram-negative and gram-positive isolates. In a greenhouse study, 28 of 86 prairie plant endophytes were found to colonize

Denise K. Zinniel; Patricia A. Lambrecht; N. Beth Harris; Zhengyu Feng; Daniel Kuczmarski; Phyllis Higley; Carol A. Ishimaru; Alahari Arunakumari; Raul G. Barletta; Anne M. Vidaver

2002-01-01

243

Rapid Test for Determining the Intracellullar Rhodanese Activity of Various Bacteria  

Microsoft Academic Search

A simple, reproducible technique with potential taxonomic application was developed for the rapid detection of rhodanese activity in gram-negative and gram-positive bacteria. The method requires suspension of the growth from three colonies in a solution of lysozyme and ethylenediaminetetraacetic acid for 60 min. After cell lysis, the presence of rhodanese activity is determined colorimetrically by measuring the amount of thiocyanate

PETER A. VANDENBERGH; ROGER E. BAWDON; RICHARD S. BERK

244

Simultaneous Fluorescent Gram Staining and Activity Assessment of Activated Sludge Bacteria  

Microsoft Academic Search

Wastewater treatment is one of the most important commercial biotechnological processes, and yet the component bacterial populations and their associated metabolic activities are poorly understood. The novel fluorescent dye hexidium iodide allows assessment of Gram status by differential absorption through bacterial cell walls. Differentiation between gram-positive and gram-negative wastewater bacteria was achieved after flow cytometric analysis. This study shows that

Scott Forster; Jason R. Snape; Hilary M. Lappin-Scott; Jonathan Porter

2002-01-01

245

RELATIONSHIP OF RUMEN GRAM-NEGATIVE BACTERIA AND FREE ENDOTOXIN TO LACTIC ACIDOSIS IN CATTLE x  

Microsoft Academic Search

SUMMARY Feeding grain to animals not adapted to grain resulted in a marked increase in the .\\/ . concentration of free endotoxln m the rumen. Endotoxin concentration increased 15 to 18 times within 12 hr after lactic acidosis was induced through grain engorgement. The increase was accompanied by a shift from predominantly gram-negative to gram-positive bacteria. Data from in vitro

T. G. Nagaraja; E. E. Bartley; L. R. Fina; H. D. Anthony

2010-01-01

246

Correlation between Major Constituents and Antibacterial Activities of Some Plant Essential Oils against Some Pathogenic Bacteria  

Microsoft Academic Search

Five different plant essential oils (Satureja hortensis, Thymus sipyleus ssp. rosulans, Thymus haussknechtii, Origanum rotundifolium (cultured form) and Origanum acutidens (wild and cultured form)) and their two major constituents carvacarol and thymol were evaluated for antibacterial activity against food-borne Gram negative (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella enteritidis) and Gram positive bacteria (Bacillus subtilis, Streptococcus pyogenes and Enterococcus

Neslihan Dikbas; Recep Kotan; Fatih Dadasoglu; Kenan Karagöz; Ramazan Çakmakci

247

Photocatalytic disinfection of spoilage bacteria Pseudomonas fluorescens and Macrococcus caseolyticus by nano-TiO2  

Technology Transfer Automated Retrieval System (TEKTRAN)

Photocatalytic disinfection of spoilage bacteria gram-negative (G-) P. fluorescens and gram-positive (G+) M. caseolyticus by nano-TiO2 under different experimental conditions and the disinfection mechanism were investigated. The experimental conditions included the initial bacterial populations, nan...

248

Methanobactin: a copper binding compound having antibiotic and antioxidant activity isolated from methanotrophic bacteria  

DOEpatents

A means and method for treating bacterial infection, providing antioxidant activity, and chelating copper using a copper binding compound produced by methanotrophic bacteria is described. The compound, known as methanobactin, is the first of a new class of antibiotics having gram-positive activity. Methanobactin has been sequenced, and its structural formula determined.

DiSpirito, Alan A. (Ames, IA); Zahn, James A. (Harbor Beach, MI); Graham, David W. (Lawrence, KS); Kim, Hyung J. (St. Paul, MN); Alterman, Michail (Lawrence, KS); Larive, Cynthia (Lawrence, KS)

2007-04-03

249

Effect of microwave irradiation on cellular disintegration of Gram positive and negative cells  

Microsoft Academic Search

This research investigated the effect of microwave irradiation (MWI) on cell disintegration in municipal secondary sludge\\u000a (MSS). A representative MSS Gram-positive bacterium (Bacillus subtilis) and Gram-negative bacteria (Acinetobacter calcoaceticus and Pseudomonas aeruginosa) were pure cultured separately and treated using MWI. Compared to untreated controls, MWI significantly increased the soluble\\u000a chemical oxygen demand (COD) (1.8–4.0-fold), soluble protein concentration (1.1–1.8-fold), and soluble

Bi Wen Zhou; Seung Gu Shin; KwangHyun Hwang; Johng-Hwa Ahn; Seokhwan Hwang

2010-01-01

250

The complete genome sequence of the Gram-positive bacterium Bacillus subtilis  

Microsoft Academic Search

Bacillus subtilis is the best-characterized member of the Gram-positive bacteria. Its genome of 4,214,810 base pairs comprises 4,100 protein-coding genes. Of these protein-coding genes, 53% are represented once, while a quarter of the genome corresponds to several gene families that have been greatly expanded by gene duplication, the largest family containing 77 putative ATP-binding transport proteins. In addition, a large

F. Kunst; N. Ogasawara; I. Moszer; A. M. Albertini; G. Alloni; V. Azevedo; M. G. Bertero; P. Bessières; A. Bolotin; S. Borchert; R. Borriss; L. Boursier; A. Brans; M. Braun; S. C. Brignell; S. Bron; S. Brouillet; C. V. Bruschi; B. Caldwell; V. Capuano; N. M. Carter; S.-K. Choi; J.-J. Codani; I. F. Connerton; N. J. Cummings; R. A. Daniel; F. Denizot; K. M. Devine; A. Düsterhöft; S. D. Ehrlich; P. T. Emmerson; K. D. Entian; J. Errington; C. Fabret; E. Ferrari; D. Foulger; C. Fritz; M. Fujita; Y. Fujita; S. Fuma; A. Galizzi; N. Galleron; S.-Y. Ghim; P. Glaser; A. Goffeau; E. J. Golightly; G. Grandi; G. Guiseppi; B. J. Guy; K. Haga; J. Haiech; C. R. Harwood; A. Hénaut; H. Hilbert; S. Holsappel; S. Hosono; M.-F. Hullo; M. Itaya; L. Jones; B. Joris; D. Karamata; Y. Kasahara; M. Klaerr-Blanchard; C. Klein; Y. Kobayashi; P. Koetter; G. Koningstein; S. Krogh; M. Kumano; K. Kurita; A. Lapidus; S. Lardinois; J. Lauber; V. Lazarevic; S.-M. Lee; A. Levine; H. Liu; S. Masuda; C. Mauël; C. Médigue; N. Medina; R. P. Mellado; M. Mizuno; D. Moestl; S. Nakai; M. Noback; D. Noone; M. O'Reilly; K. Ogawa; A. Ogiwara; B. Oudega; S.-H. Park; V. Parro; T. M. Pohl; D. Portetelle; S. Porwollik; A. M. Prescott; E. Presecan; P. Pujic; B. Purnelle; G. Rapoport; M. Rieger; S. Reynolds; C. Rivolta; E. Rocha; B. Roche; M. Rose; Y. Sadaie; T. Sato; E. Scanlan; S. Schleich; R. Schroeter; F. Scoffone; J. Sekiguchi; A. Sekowska; S. J. Seror; P. Serror; B.-S. Shin; B. Soldo; A. Sorokin; E. Tacconi; T. Takagi; H. Takahashi; K. Takemaru; M. Takeuchi; A. Tamakoshi; T. Tanaka; P. Terpstra; A. Tognoni; V. Tosato; S. Uchiyama; M. Vandenbol; F. Vannier; A. Vassarotti; A. Viari; R. Wambutt; E. Wedler; H. Wedler; T. Weitzenegger; P. Winters; A. Wipat; H. Yamamoto; K. Yamane; K. Yasumoto; K. Yata; K. Yoshida; H.-F. Yoshikawa; E. Zumstein; H. Yoshikawa; A. Danchin

1997-01-01

251

The complete genome sequence of the gram-positive bacterium Bacillus subtilis  

Microsoft Academic Search

Bacillus subtilis is the best-characterized member of the Gram-positive bacteria. Its genome of 4,214,810 base pairs comprises 4,100 protein-coding genes. Of these protein-coding genes, 53% are represented once, while a quarter of the genome corresponds to several gene families that have been greatly expanded by gene duplication, the largest family containing 77 putative ATP-binding transport proteins. In addition, a large

F. Kunst; N. Ogasawara; I. Moszer; A. M. Albertini; G. Alloni; V. Azevedo; M. G. Bertero; P. Bessières; A. Bolotin; S. Borchert; R. Borriss; L. Boursier; A. Brans; M. Braun; S. C. Brignell; S. Bron; S. Brouillet; C. V. Bruschi; B. Caldwell; V. Capuano; N. M. Carter; S.-K. Choi; J.-J. Codani; I. F. Connerton; A. Danchin

1997-01-01

252

Bacteria in the Cafeteria  

NSDL National Science Digital Library

This activity from the American Museum of Natural History's family magazine series challenges kids to go on a microbe quest to solve a riddle. The online activity begins with a page of directions for how to find the missing letters of the riddle. As kids click their way around a virtual lunchroom, they are given 11 Yes/No questions asking whether the featured bacteria helps people. Along with the answer to the riddle, kids get a round of applause when they correctly answer all 11 questions.

253

Bacteria in Solitary Confinement  

PubMed Central

Even in clonal bacterial cultures, individual bacteria can show substantial stochastic variation, leading to pitfalls in the interpretation of data derived from millions of cells in a culture. In this issue of the Journal of Bacteriology, as part of their study on osmoadaptation in a cyanobacterium, Nanatani et al. describe employing an ingenious microfluidic device that gently cages individual cells (J Bacteriol 197:676–687, 2015, http://dx.doi.org/10.1128/JB.02276-14). The device is a welcome addition to the toolkit available to probe the responses of individual cells to environmental cues. PMID:25488297

2014-01-01

254

Isolation and Characterization of Bacteria from Ancient Siberian Permafrost Sediment  

PubMed Central

In this study, we isolated and characterized bacterial strains from ancient (Neogene) permafrost sediment that was permanently frozen for 3.5 million years. The sampling site was located at Mammoth Mountain in the Aldan river valley in Central Yakutia in Eastern Siberia. Analysis of phospolipid fatty acids (PLFA) demonstrated the dominance of bacteria over fungi; the analysis of fatty acids specific for Gram-positive and Gram-negative bacteria revealed an approximately twofold higher amount of Gram-negative bacteria compared to Gram-positive bacteria. Direct microbial counts after natural permafrost enrichment showed the presence of (4.7 ± 1.5) × 108 cells g?1 sediment dry mass. Viable heterotrophic bacteria were found at 0 °C, 10 °C and 25 °C, but not at 37 °C. Spore-forming bacteria were not detected. Numbers of viable fungi were low and were only detected at 0 °C and 10 °C. Selected culturable bacterial isolates were identified as representatives of Arthrobacter phenanthrenivorans, Subtercola frigoramans and Glaciimonas immobilis. Representatives of each of these species were characterized with regard to their growth temperature range, their ability to grow on different media, to produce enzymes, to grow in the presence of NaCl, antibiotics, and heavy metals, and to degrade hydrocarbons. All strains could grow at ?5 °C; the upper temperature limit for growth in liquid culture was 25 °C or 30 °C. Sensitivity to rich media, antibiotics, heavy metals, and salt increased when temperature decreased (20 °C > 10 °C > 1 °C). In spite of the ligninolytic activity of some strains, no biodegradation activity was detected. PMID:24832653

Zhang, De-Chao; Brouchkov, Anatoli; Griva, Gennady; Schinner, Franz; Margesin, Rosa

2013-01-01

255

Isolation and characterization of bacteria from ancient siberian permafrost sediment.  

PubMed

In this study, we isolated and characterized bacterial strains from ancient (Neogene) permafrost sediment that was permanently frozen for 3.5 million years. The sampling site was located at Mammoth Mountain in the Aldan river valley in Central Yakutia in Eastern Siberia. Analysis of phospolipid fatty acids (PLFA) demonstrated the dominance of bacteria over fungi; the analysis of fatty acids specific for Gram-positive and Gram-negative bacteria revealed an approximately twofold higher amount of Gram-negative bacteria compared to Gram-positive bacteria. Direct microbial counts after natural permafrost enrichment showed the presence of (4.7 ± 1.5) × 108 cells g-1 sediment dry mass. Viable heterotrophic bacteria were found at 0 °C, 10 °C and 25 °C, but not at 37 °C. Spore-forming bacteria were not detected. Numbers of viable fungi were low and were only detected at 0 °C and 10 °C. Selected culturable bacterial isolates were identified as representatives of Arthrobacter phenanthrenivorans, Subtercola frigoramans and Glaciimonas immobilis. Representatives of each of these species were characterized with regard to their growth temperature range, their ability to grow on different media, to produce enzymes, to grow in the presence of NaCl, antibiotics, and heavy metals, and to degrade hydrocarbons. All strains could grow at -5 °C; the upper temperature limit for growth in liquid culture was 25 °C or 30 °C. Sensitivity to rich media, antibiotics, heavy metals, and salt increased when temperature decreased (20 °C > 10 °C > 1 °C). In spite of the ligninolytic activity of some strains, no biodegradation activity was detected. PMID:24832653

Zhang, De-Chao; Brouchkov, Anatoli; Griva, Gennady; Schinner, Franz; Margesin, Rosa

2013-01-01

256

Aerobic salivary bacteria in wild and captive Komodo dragons.  

PubMed

During the months of November 1996, August 1997, and March 1998, saliva and plasma samples were collected for isolation of aerobic bacteria from 26 wild and 13 captive Komodo dragons (Varanus komodoensis). Twenty-eight Gram-negative and 29 Gram-positive species of bacteria were isolated from the saliva of the 39 Komodo dragons. A greater number of wild than captive dragons were positive for both Gram-negative and Gram-positive bacteria. The average number of bacterial species within the saliva of wild dragons was 46% greater than for captive dragons. While Escherichia coli was the most common bacterium isolated from the saliva of wild dragons, this species was not present in captive dragons. The most common bacteria isolated from the saliva of captive dragons were Staphylococcus capitis and Staphylococcus capitis and Staphylococcus caseolyticus, neither of which were found in wild dragons. High mortality was seen among mice injected with saliva from wild dragons and the only bacterium isolated from the blood of dying mice was Pasteurella multocida. A competitive inhibition enzyme-linked immunosorbent assay revealed the presence of anti-Pasteurella antibody in the plasma of Komodo dragons. Four species of bacteria isolated from dragon saliva showed resistance to one or more of 16 antimicrobics tested. The wide variety of bacteria demonstrated in the saliva of the Komodo dragon in this study, at least one species of which was highly lethal in mice and 54 species of which are known pathogens, support the observation that wounds inflicted by this animal are often associated with sepsis and subsequent bacteremia in prey animals. PMID:12238371

Montgomery, Joel M; Gillespie, Don; Sastrawan, Putra; Fredeking, Terry M; Stewart, George L

2002-07-01

257

Designing surfaces that kill bacteria on contact  

NASA Astrophysics Data System (ADS)

Poly(4-vinyl-N-alkylpyridinium bromide) was covalently attached to glass slides to create a surface that kills airborne bacteria on contact. The antibacterial properties were assessed by spraying aqueous suspensions of bacterial cells on the surface, followed by air drying and counting the number of cells remaining viable (i.e., capable of growing colonies). Amino glass slides were acylated with acryloyl chloride, copolymerized with 4-vinylpyridine, and N-alkylated with different alkyl bromides (from propyl to hexadecyl). The resultant surfaces, depending on the alkyl group, were able to kill up to 94 ± 4% of Staphylococcus aureus cells sprayed on them. A surface alternatively created by attaching poly(4-vinylpyridine) to a glass slide and alkylating it with hexyl bromide killed 94 ± 3% of the deposited S. aureus cells. On surfaces modified with N-hexylated poly(4-vinylpyridine), the numbers of viable cells of another Gram-positive bacterium, Staphylococcus epidermidis, as well as of the Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli, dropped more than 100-fold compared with the original amino glass. In contrast, the number of viable bacterial cells did not decline significantly after spraying on such common materials as ceramics, plastics, metals, and wood.

Tiller, Joerg C.; Liao, Chun-Jen; Lewis, Kim; Klibanov, Alexander M.

2001-05-01

258

Nitrogen control in bacteria.  

PubMed Central

Nitrogen metabolism in prokaryotes involves the coordinated expression of a large number of enzymes concerned with both utilization of extracellular nitrogen sources and intracellular biosynthesis of nitrogen-containing compounds. The control of this expression is determined by the availability of fixed nitrogen to the cell and is effected by complex regulatory networks involving regulation at both the transcriptional and posttranslational levels. While the most detailed studies to date have been carried out with enteric bacteria, there is a considerable body of evidence to show that the nitrogen regulation (ntr) systems described in the enterics extend to many other genera. Furthermore, as the range of bacteria in which the phenomenon of nitrogen control is examined is being extended, new regulatory mechanisms are also being discovered. In this review, we have attempted to summarize recent research in prokaryotic nitrogen control; to show the ubiquity of the ntr system, at least in gram-negative organisms; and to identify those areas and groups of organisms about which there is much still to learn. PMID:8531888

Merrick, M J; Edwards, R A

1995-01-01

259

Can entropy save bacteria?  

E-print Network

This article presents a physical biology approach to understanding organization and segregation of bacterial chromosomes. The author uses a "piston" analogy for bacterial chromosomes in a cell, which leads to a phase diagram for the organization of two athermal chains confined in a closed geometry characterized by two length scales (length and width). When applied to rod-shaped bacteria such as Escherichia coli, this phase diagram predicts that, despite strong confinement, duplicated chromosomes will demix, i.e., there exists a primordial physical driving force for chromosome segregation. The author discusses segregation of duplicating chromosomes using the concentric-shell model, which predicts that newly synthesized DNA will be found in the periphery of the chromosome during replication. In contrast to chromosomes, these results suggest that most plasmids will be randomly distributed inside the cell because of their small sizes. An active partitioning system is therefore required for accurate segregation of low-copy number plasmids. Implications of these results are also sketched, e.g., on the role of proteins, segregation mechanisms for bacteria of diverse shapes, cell cycle of an artificial cell, and evolution.

Suckjoon Jun

2008-08-29

260

TSSWCB Bacteria-Related Projects  

E-print Network

of the projects are listed below. ? Peach CreekWater Quality Improvement Project ? Monitoring and Educational Programs Focused on Bacteria and Nutrient Runoff on Dairy Operations in the LeonWatershed ? Development of the Plum CreekWPP ? Impact of Proper... Star Healthy Streams * ? Environmental Management of Grazing Lands * *TWRI-managed projects More information on the initiative is available at www.tsswcb.state.tx.us/managementprogram/ initiatives/bacteria. Bacteria Projects Across the State...

Wythe, Kathy

2007-01-01

261

Activation of human endothelial cells by viable or heat-killed gram-negative bacteria requires soluble CD14.  

PubMed Central

In response to bacterial lipopolysaccharides (LPS; endotoxin), endothelial cells are converted to an activation phenotype expressing both proinflammatory and procoagulant properties that include the induction of leukocyte adhesion molecules and tissue factor expression. LPS-induced endothelial cell activation requires a soluble form of the monocyte LPS receptor, sCD14. We evaluated the capacity of multiple strains of gram-negative and gram-positive bacteria to induce endothelial E-selectin and tissue factor expression through sCD14-dependent pathways with cultured human umbilical vein endothelial cells (HUVE). Both viable and heat-killed gram-negative bacteria (Bacteroides fragilis, Enterobacter cloacae, Haemophilus influenzae, and Klebsiella pneumoniae) but not viable or heat-killed gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, and Streptococcus pneumoniae) induced prominent E-selectin surface expression detected by enzyme-linked immunosorbent assay. Tissue factor activity on HUVE, indicated by factor X activation, was induced in response to gram-negative bacteria but not in response to gram-positive bacteria. Gram-negative bacteria induced transcriptional activation in HUVE, indicated by the appearance of E-selectin-specific mRNA and by the demonstration of activation of NF-kappa B, a trans-activating factor necessary for E-selectin and tissue factor gene transcription. In contrast, neither E-selectin mRNA nor activation of NF-kappa B was detected in HUVE treated with gram-positive bacteria. Endothelial cell activation by gram-negative bacteria in each of these assays was inhibited with a monoclonal antibody (60bd) against CD14. Furthermore, CHO-K1 cells, transfected with human recombinant CD14, responded to all strains of gram-negative bacteria (viable or heat killed), indicated by CHO-K1 NF-kappa B activation. We conclude that gram-negative bacteria induce endothelial cell activation through a common sCD14-dependent pathway. PMID:7558318

Noel, R F; Sato, T T; Mendez, C; Johnson, M C; Pohlman, T H

1995-01-01

262

Microcins from Enterobacteria: On the Edge Between Gram-Positive Bacteriocins and Colicins  

NASA Astrophysics Data System (ADS)

Most bacteria and archaea produce gene-encoded antimicrobial peptides/proteins called bacteriocins, which are secreted by the producing bacteria to compete against other microorganisms in a given niche. They are considered important mediators of intra- and interspecies interactions and therefore a factor in ­maintaining the microbial diversity and stability. They are ribosomally synthesized, and most of them are produced as inactive precursor proteins, which in some cases are further enzymatically modified. Bacteriocins generally exert potent antibacterial activities directed against bacterial species closely related to the producing bacteria. Bacteriocins are abundant and diverse in Gram-negative and Gram-positive bacteria. This chapter focuses on colicins and microcins from enterobacteria (mainly Escherichia coli) and on bacteriocins from lactic acid bacteria (LAB). Microcins are the lower-molecular-mass bacteriocins produced by Gram-negative bacteria with a repertoire of only 14 representatives. They form a very restricted family of bacteriocins, compared to the huge family of LAB bacteriocins that is constituted of several hundreds of peptides, with which microcins share common characteristics. Nevertheless, microcins also show similarities, particularly in their uptake mechanisms, with the higher-molecular-mass colicins, also produced by E. coli strains. On the edge between LAB bacteriocins and colicins, microcins appear to combine highly efficient strategies developed by both Gram-positive and Gram-negative bacteria at different levels, including uptake, translocation, killing of target cells, and immunity of the producing bacteria, making them important actors of bacterial competitions and fascinating models for novel concepts toward antimicrobial strategies and against resistance mechanisms.

Rebuffat, Sylvie

263

Heteropolysaccharides from lactic acid bacteria  

Microsoft Academic Search

Microbial exopolysaccharides are biothickeners that can be added to a wide variety of food products, where they serve as viscosifying, stabilizing, emulsifying or gelling agents. Numerous exopolysaccharides with different composition, size and structure are synthesized by lactic acid bacteria. The heteropolysaccharides from both mesophilic and thermophilic lactic acid bacteria have received renewed interest recently. Structural analysis combined with rheological studies

Luc De Vuyst; Bart Degeest

1999-01-01

264

The Genus Corynebacterium and Other Medically Relevant Coryneform-Like Bacteria  

PubMed Central

Catalase-positive Gram-positive bacilli, commonly called “diphtheroids” or “coryneform” bacteria were historically nearly always dismissed as contaminants when recovered from patients, but increasingly have been implicated as the cause of significant infections. These taxa have been underreported, and the taxa were taxonomically confusing. The mechanisms of pathogenesis, especially for newly described taxa, were rarely studied. Antibiotic susceptibility data were relatively scant. In this minireview, clinical relevance, phenotypic and genetic identification methods, matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) evaluations, and antimicrobial susceptibility testing involving species in the genus Corynebacterium and other medically relevant Gram-positive rods, collectively called coryneforms, are described. PMID:22837327

2012-01-01

265

Synergistic antimicrobial activity of combinations of sanguinarine and EDTA with vancomycin against multidrug resistant bacteria.  

PubMed

A combination of antimicrobial drugs has a potential to overcome multidrug resistant pathogens. In our study we tested the combination of an antimicrobial DNA-intercalating alkaloid (sanguinarine), a chelator (EDTA) with a standard antibiotic (vancomycin), i.e. drugs, which differ in their mode of action. The antibacterial activities of individual substances and of two-drug and three-drug combinations were evaluated for 34 strains of Gram-positive and Gramnegative bacteria (among them 23 clinical isolates) which are not sensitive for vancomycin. MIC and MBC values were determined for each drug individually. Sanguinarine demonstrated a strong activity against all the strains; its activity was comparable to that of antibiotics (MIC = 0.5 - 128 µg/ml). Time kill pharmacokinetics were studied for different concentrations of sanguinarine. A sanguinarine concentration of 16 x MIC was bactericidal against both Gram-positive and Gram-negative strains within 4 to 6 h of incubation. EDTA has only bacteriostatic activity against both Gram-positive and Gram-negative bacteria. As expected, vancomycin is active against Gram-positive bacteria (MIC = 0.125 - 16 µg/ml) but much weaker against Gram-negative bacteria (MIC = 4 - 128 µg/ml). Using the checkerboard design, two- and threedrug combinations were evaluated. Additive and synergistic effects were recorded for all sanguinarine + EDTA and sanguinarine + EDTA + vancomycin combinations against Gram-negative bacteria. Time kill assays indicated that only the combination of 1 x MIC sanguinarine + 1 x MIC EDTA + 1 x MIC vancomycin resulted in a synergistic interaction against MRSA. In the combination assays Gram-negative bacteria became sensitive for vancomycin. More experiments are needed to demonstrate that such a combination strategy also works under in vivo conditions and is clinically relevant. PMID:25692301

Hamoud, Razan; Reichling, Jurgen; Wink, Michael

2014-01-01

266

Distribution of Heterotrophic Bacteria in Lake Shira  

Microsoft Academic Search

A study of the horizontal and vertical distribution of heterotrophic bacteria in brackish Lake Shira in summer periods showed that mesophilic bacteria dominated in all areas of the lake, whereas psychrotolerant bacteria dominated in the metalimnion and hypolimnion of its central part. Nonhalophilic bacteria were mostly mesophilic and dominated in coastal waters. Most psychrotolerant bacteria were able to grow in

T. I. Lobova; L. V. Listova; L. Yu. Popova

2004-01-01

267

High osmolarity improves the electro-transformation efficiency of the gram-positive bacteria Bacillus subtilis and Bacillus licheniformis  

Microsoft Academic Search

A high osmolarity electroporation method has been developed for the efficient transformation of Bacillus subtilis and B. licheniformis. The presence of high concentrations of the osmoticums, sorbitol and mannitol, in the electroporation, growth and recovery media resulted in an approximately 5000-fold increase in the transformation efficiency of B. subtilis, with a maximum value of 1.4×106 transformants per ?g DNA. The

Gang-Ping Xue; Jennifer S Johnson; Brian P Dalrymple

1999-01-01

268

Mechanism of action of recombinant Acc-royalisin from royal jelly of Chinese honeybee against gram-positive bacteria  

Technology Transfer Automated Retrieval System (TEKTRAN)

The antibacterial activity of royalisin, an antimicrobial peptide from the royal jelly produced by honeybees has been addressed extensively. However, its mechanism of action remains unclear. In this study, a recombinant royalisin, RAcc-royalisin from the royal jelly of Chinese honeybee Apis cerana...

269

Bacteria belonging to the genus Oceanobacillus are Gram-positive, aerobic, motile, rod-shaped, and spore-forming (Yumoto  

E-print Network

, 1.8 g calcium chloride, 0.55 g potassium chloride, 0.16 g sodium bicarbonate, 0.08 g potassium extract, 0.1 g ferric citrate, 19.45 g sodium chloride, 5.9 g magnesium chloride, 3.24 g magnesium sulfate bromide, 34 mg strontium chloride, 22 mg boric acid, 4 mg sodium silicate, 2.4 mg sodium fluoride, 1.6 mg

Bae, Jin-Woo

270

Antibacterial activity of silver-doped hydroxyapatite nanoparticles against gram-positive and gram-negative bacteria  

PubMed Central

Ag-doped nanocrystalline hydroxyapatite nanoparticles (Ag:HAp-NPs) (Ca10-xAgx(PO4)6(OH)2, xAg?=?0.05, 0.2, and 0.3) with antibacterial properties are of great interest in the development of new products. Coprecipitation method is a promising route for obtaining nanocrystalline Ag:HAp with antibacterial properties. X-ray diffraction identified HAp as an unique crystalline phase in each sample. The calculated lattice constants of a?=?b?=?9.435 Å, c?=?6.876 Å for xAg?=?0.05, a?=?b?=?9.443 Å, c?=?6.875 Å for xAg?=?0.2, and a?=?b?=?9.445 Å, c?=?6.877 Å for xAg?=?0.3 are in good agreement with the standard of a?=?b?=?9.418 Å, c?=?6.884 Å (space group P63/m). The Fourier transform infrared and Raman spectra of the sintered HAp show the absorption bands characteristic to hydroxyapatite. The Ag:HAp nanoparticles are evaluated for their antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae, Providencia stuartii, Citrobacter freundii and Serratia marcescens. The results showed that the antibacterial activity of these materials, regardless of the sample types, was greatest against S. aureus, K. pneumoniae, P. stuartii, and C. freundii. The results of qualitative antibacterial tests revealed that the tested Ag:HAp-NPs had an important inhibitory activity on P. stuartii and C. freundii. The absorbance values measured at 490 nm of the P. stuartii and C. freundii in the presence of Ag:HAp-NPs decreased compared with those of organic solvent used (DMSO) for all the samples (xAg?=?0.05, 0.2, and 0.3). Antibacterial activity increased with the increase of xAg in the samples. The Ag:HAp-NP concentration had little influence on the bacterial growth (P. stuartii). PMID:22721352

2012-01-01

271

Design and synthesis of novel antimicrobials with activity against Gram-positive bacteria and mycobacterial species, including M. tuberculosis  

PubMed Central

The alarming increase in bacterial resistance over the last decade along with a dramatic decrease in new treatments for infections has led to problems in the healthcare industry. Tuberculosis (TB) is caused mainly by Mycobacterium tuberculosis which is responsible for 1.4 million deaths per year. A world-wide threat with HIV co-infected with multi and extensively drug-resistant strains of TB has emerged. In this regard, herein, novel acrylic acid ethyl ester derivatives were synthesized in simple, efficient routes and evaluated as potential agents against several Mycobacterium species. These were synthesized via a stereospecific process for structure activity relationship (SAR) studies. Minimum inhibitory concentration (MIC) assays indicated that esters 12, 13, and 20 exhibited greater in vitro activity against Mycobacterium smegmatis than rifampin, one of the current, first-line anti-mycobacterial chemotherapeutic agents. Based on these studies the acrylic ester 20 has been developed as a potential lead compound which was found to have an MIC value of 0.4 ?g/mL against Mycobacterium tuberculosis. The SAR and biological activity of this series is presented; a Michael – acceptor mechanism appears to be important for potent activity of this series of analogs. PMID:24200931

Tiruveedhula, V.V.N. Phani Babu; Witzigmann, Christopher M.; Verma, Ranjit; Kabir, M. Shahjahan; Rott, Marc; Schwan, William R.; Medina-Bielski, Sara; Lane, Michelle; Close, William; Polanowski, Rebecca L.; Sherman, David; Monte, Aaron; Deschamps, Jeffrey R.; Cook, James M.

2013-01-01

272

Design and synthesis of novel antimicrobials with activity against Gram-positive bacteria and mycobacterial species, including M. tuberculosis.  

PubMed

The alarming increase in bacterial resistance over the last decade along with a dramatic decrease in new treatments for infections has led to problems in the healthcare industry. Tuberculosis (TB) is caused mainly by Mycobacterium tuberculosis which is responsible for 1.4 million deaths per year. A world-wide threat with HIV co-infected with multi and extensively drug-resistant strains of TB has emerged. In this regard, herein, novel acrylic acid ethyl ester derivatives were synthesized in simple, efficient routes and evaluated as potential agents against several Mycobacterium species. These were synthesized via a stereospecific process for structure activity relationship (SAR) studies. Minimum inhibitory concentration (MIC) assays indicated that esters 12, 13, and 20 exhibited greater in vitro activity against Mycobacterium smegmatis than rifampin, one of the current, first-line anti-mycobacterial chemotherapeutic agents. Based on these studies the acrylic ester 20 has been developed as a potential lead compound which was found to have an MIC value of 0.4 ?g/mL against Mycobacterium tuberculosis. The SAR and biological activity of this series is presented; a Michael-acceptor mechanism appears to be important for potent activity of this series of analogs. PMID:24200931

Tiruveedhula, V V N Phani Babu; Witzigmann, Christopher M; Verma, Ranjit; Kabir, M Shahjahan; Rott, Marc; Schwan, William R; Medina-Bielski, Sara; Lane, Michelle; Close, William; Polanowski, Rebecca L; Sherman, David; Monte, Aaron; Deschamps, Jeffrey R; Cook, James M

2013-12-15

273

Direct screening of recombinants in gram-positive bacteria using the secreted staphylococcal nuclease as a reporter.  

PubMed Central

A system for direct screening of recombinant clones in Lactococcus lactis, based on secretion of the staphylococcal nuclease (SNase) in the organism, was developed. The nuc gene (encoding SNase) was cloned on both rolling-circle and theta-replicating plasmids. L. lactis strains containing these nuc+ plasmids secrete SNase and are readily detectable by a simple plate test. A multicloning site (MCS) was introduced just after the cleavage site between leader peptide and the mature SNase, without affecting nuclease activity. Cloning foreign DNA fragments into any site of the MCS interrupts nuc and thus results in nuc mutant clones which are easily distinguished fron nuc+ clones on plates. The utility of this system for L. lactis was demonstrated by cloning an antibiotic resistance marker and Escherichia coli chromosomal DNA fragments into the MCS of the nucMCS cassette. Both cloning vectors containing the nucMCS cassette were also introduced into Streptococcus salivarius subsp. thermophilus, in which direct screening of nuc mutant recombinant clones was also achieved. The potential uses of nuc as a secretion reporter system are discussed. Images PMID:8051029

Le Loir, Y; Gruss, A; Ehrlich, S D; Langella, P

1994-01-01

274

Presence of erm gene classes in Gram-positive bacteria of animal and human origin in Denmark  

Microsoft Academic Search

A classification of the different erm gene classes based on published sequences was performed, and specific primers to detect some of these classes designed. The presence of ermA (Tn554), ermB (class IV) and ermC (class VI) was determined by PCR in a total of 113 enterococcal, 77 streptococcal and 68 staphylococcal erythromycin resistant isolates of animal and human origin. At

Lars Bogø Jensen; Niels Frimodt-Møller; Frank M Aarestrup

1999-01-01

275

Restart of DNA replication in Gram-positive bacteria: functional characterisation of the Bacillus subtilis PriA initiator  

Microsoft Academic Search

The PriA protein was identified in Escherichia coli as a factor involved in the replication of extrachromo- somal elements such as bacteriophage ?X174 and plasmid pBR322. Recent data show that PriA plays an important role in chromosomal replication, by promoting reassembly of the replication machinery during reinitiation of inactivated forks. A gene encoding a product 32% identical to the E.coli

Patrice Polard; Stéphanie Marsin; Stephen McGovern; Marion Velten; Dale B. Wigley; S. Dusko; Claude Bruand

276

Introduction Magnetotactic bacteria (MTB) biomineralize intracellular, membrane-  

E-print Network

Introduction Magnetotactic bacteria (MTB) biomineralize intracellular, membrane- bounded, magnetic in the environment. Abstract Magnetotactic bacteria is the categorical name for a group of prokaryotes of this study is on two magnetite-producing, magnetotactic sulfate-reducing bacteria (SRB), Desulfovibrio

Walker, Lawrence R.

277

Magnetic Microstructure of Magnetotactic Bacteria by  

E-print Network

Magnetic Microstructure of Magnetotactic Bacteria by Electron Holography Rafal E. Dunin microstructure of magnetite nanocrys- tals in magnetotactic bacteria. The magnetite crystals were all single). For example, magnetotactic bacteria contain magnetosomes, which are intracellular, ferri- magnetic crystals

Dunin-Borkowski, Rafal E.

278

Interactions between Diatoms and Bacteria  

PubMed Central

Summary: Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding higher trophic levels. Here we present an overview of how diatoms and bacteria interact and the implications of these interactions. We emphasize that heterotrophic bacteria in the oceans that are consistently associated with diatoms are confined to two phyla. These consistent bacterial associations result from encounter mechanisms that occur within a microscale environment surrounding a diatom cell. We review signaling mechanisms that occur in this microenvironment to pave the way for specific interactions. Finally, we discuss known interactions between diatoms and bacteria and exciting new directions and research opportunities in this field. Throughout the review, we emphasize new technological advances that will help in the discovery of new interactions. Deciphering the languages of diatoms and bacteria and how they interact will inform our understanding of the role these organisms have in shaping the ocean and how these interactions may change in future oceans. PMID:22933565

Amin, Shady A.; Parker, Micaela S.

2012-01-01

279

Bacteria Growth Inquiry: Bodily Bacteria and Healthy Hygiene Habits  

NSDL National Science Digital Library

In this inquiry activity, students generate investigable questions to explore the link between hygiene/cleanliness and bacteria growth/population. The students will present their conclusions, and video clips containing additional information will be discussed.

280

Antagonistic effect of oral bacteria towards Treponema denticola.  

PubMed Central

This study was designed to isolate oral bacteria exhibiting antagonism towards Treponema denticola and to characterize the inhibitory activity. Eleven bacterial isolates obtained from subgingival sites and identified as either Staphylococcus aureus or Streptococcus mutans were found to inhibit the growth of T. denticola. When the activity spectra of these isolates were analyzed, two additional periodontopathogens (Porphyromonas gingivalis and Prevotella intermedia) were found to be affected, whereas most gram-positive bacteria were not. Strains of S. aureus produce a bacteriocin-like inhibitory substance (heat stable and protease sensitive), whereas the inhibitory effect of S. mutans appears to be related to the production of lactic acid. The negative interactions reported in this paper may govern population shifts observed in subgingival sites. PMID:8727911

Grenier, D

1996-01-01

281

Bacteria that masquerade as fungi: actinomycosis/nocardia.  

PubMed

The order Actinomycetales includes phylogenetically diverse but morphologically similar aerobic and anaerobic bacteria that exhibit filamentous branching structures which fragment into bacillary or coccoid forms. The aerobic actinomyces are a large, diverse group of gram-positive bacteria including Nocardia, Gordona, Tsukamurella, Streptomyces, Rhodococcus, Streptomycetes, Mycobacteria, and Corynebacteria. The anaerobic genera of medical importance include Actinomyces, Arachnia, Rothia, and Bifidobacterium. Both Actinomyces and Nocardia cause similar clinical syndromes involving the lung, bone and joint, soft tissue, and the central nervous system. The medically important Actinomyces organisms cause infections characterized by chronic progression, abscess formation with fistulous tracts and draining sinuses. Called "great masqueraders," diagnosis of actinomycosis and nocardiosis is often delayed. Once recognized, treatment of these infections requires long courses of parenteral and oral therapy. This review will compare and contrast infections due to Actinomyces and Nocardia. PMID:20463251

Sullivan, Donna C; Chapman, Stanley W

2010-05-01

282

Role of commensal gut bacteria in inflammatory bowel diseases  

PubMed Central

Aberrant immune responses toward commensal gut bacteria can result in the onset and perpetuation of inflammatory bowel diseases (IBD). Reduced microbiota diversity in conjunction with lower proportion of Gram positive and higher proportion of Gram negative bacteria than in healthy subjects is frequently reported in IBD patients. In a subset of IBD patients, E. coli strains with specific features trigger disease. Important molecular mechanisms underlying this effect have been identified. However, in the majority of patients the exact nature of host-microbe interactions that contribute to IBD development has so far not been defined. The application of metagenomic techniques may help to identify bacterial functions that are involved in the aggravation or alleviation of IBD. Subsequently, the relevance for disease development of bacterial candidate genes may be tested taking advantage of reductionist animal models of chronic gut inflammation. This approach may help to identify bacterial functions that can be targeted in future concepts of IBD therapy. PMID:23060017

Loh, Gunnar; Blaut, Michael

2012-01-01

283

Sampling bacteria with a laser  

NASA Astrophysics Data System (ADS)

Water quality is a topic of high interest and it's getting more and more important due to climate change and the implementation of European Water Framework Directive (WFD). One point of interest here is the inflow of bacteria into a river caused by combined sewer overflows which lead untreated wastewater including bacteria directly into a river. These bacteria remain in the river for a certain time, they settle down and can be remobilised again. In our study we want to investigate these processes of sedimentation and resuspension and use the results for the development of a software module coupled with the software Flow3D. Thereby we should be able to simulate and therefore predict the water quality influenced by combined sewer overflows. Hence we need to get information about the bacteria transport and fate. We need to know about the size of the bacteria or of the bacteria clumps and the size of the particles the bacteria are attached to. The agglomerates lead to different characteristics and velocities of settlement. The timespan during this bacteria can be detected in the bulk phase depends on many factors like the intensity of UV light, turbidity of the water, the temperature of the water, if there are grazers and a lot more. The size, density and composition of the agglomerates is just a part of all these influencing factors, but it is extremely difficult to differ between the other effects if we have no information about the simple sedimentation in default of these basic information. However we have a big problem getting the data. The chaining between bacteria or bacteria and particles is not too strong, so filtering the water to get a sieving curve may destroy these connections. We did some experiments similar to PIV (particle image velocimetry) measurements and evaluated the pictures with a macro written for the software ImageJ. Doing so we were able to get the concentration of bacteria in the water and collect information about the size of the bacteria. We also compared these data to samples of usual collection and filtering. The results of these laser measurements are very promising.

Schwarzwälder, Kordula; Rutschmann, Peter

2014-05-01

284

Determination of the gram-positive bacterial content of soils and sediments by analysis of teichoic acid components  

NASA Technical Reports Server (NTRS)

Many gram-positive bacteria form substituted polymers of glycerol and ribitol phosphate esters known as teichoic acids. Utilizing the relative specificity of cold concentrated hydrofluoric acid in the hydrolysis of polyphosphate esters it proved possible to quantitatively assay the teichoic acid-derived glycerol and ribitol from gram-positive bacteria added to various soils and sediments. The lipids are first removed from the soils or sediments with a one phase chloroform-methanol extraction and the lipid extracted residue is hydrolyzed with cold concentrated hydrofluoric acid. To achieve maximum recovery of the teichoic acid ribitol, a second acid hydrolysis of the aqueous extract is required. The glycerol and ribitol are then acetylated after neutralization and analyzed by capillary gas-liquid chromatography. This technique together with measures of the total phospholipid, the phospholipid fatty acid, the muramic acid and the hydroxy fatty acids of the lipopolysaccharide lipid A of the gram-negative bacteria makes it possible to describe the community structure environmental samples. The proportion of gram-positive bacteria measured as the teichoic acid glycerol and ribitol is higher in soils than in sediments and increases with depth in both.

Gehron, M. J.; Davis, J. D.; Smith, G. A.; White, D. C.

1984-01-01

285

Gram-typing of mastitis bacteria in milk samples using flow cytometry.  

PubMed

Fast identification of pathogenic bacteria in milk samples from cows with clinical mastitis is central to proper treatment. In Denmark, time to bacterial diagnosis is typically 24 to 48 h when using traditional culturing methods. The PCR technique provides a faster and highly sensitive identification of bacterial pathogens, although shipment of samples to diagnostic laboratories delays treatment decisions. Due to the lack of fast on-site tests that can identify the causative pathogens, antibiotic treatments are often initiated before bacterial identification. The present study describes a flow cytometry-based method, which can detect and distinguish gram-negative and gram-positive bacteria in mastitis milk samples. The differentiation was based on bacterial fluorescence intensities upon labeling with biotin-conjugated wheat germ agglutinin and acridine orange. Initially 19 in-house bacterial cultures (4 gram-negative and 15 gram-positive strains) were analyzed, and biotin-conjugated wheat germ agglutinin and acridine orange florescence intensities were determined for gram-negative and gram-positive bacteria, respectively. Fluorescence cut-off values were established based on receiver operating characteristic curves for the 19 bacterial cultures. The method was then tested on 53 selected mastitis cases obtained from the department biobank (milk samples from 6 gram-negative and 47 gram-positive mastitis cases). Gram-negative bacteria in milk samples were detected with a sensitivity of 1 and a specificity of 0.74, when classification was based on the previously established cut-off values. However, when receiver operating characteristic curves were constructed for the 53 mastitis cases, results indicate that a sensitivity and specificity of 1 could be reached if cut-off values were reduced. This flow cytometry-based technique could potentially provide dairy farmers and attending veterinarians with on-site information on bacterial gram-type and prevent ineffective antimicrobial treatment in mastitis cases caused by gram-negative bacteria. PMID:23141826

Langerhuus, S N; Ingvartsen, K L; Bennedsgaard, T W; Røntved, C M

2013-01-01

286

Nitrogen Requirements and Uricolytic Activity of Cutaneous Bacteria  

PubMed Central

Uric acid, but not xanthine, was degraded by gram-positive catalase-producing cocci and diphtheroids which represented the two predominant human autochthonous skin bacteria. The proportions of uricolytic cocci and diphtheroids varied with the cutaneous site sampled. Uric acid and allantoin were not utilized by cocci or diphtheroids as sole sources of nitrogen. Uric acid appeared to act only as a secondary substrate for the gram-positive bacteria. Cutaneous cocci are known to be ureolytic but few diphtheroids had urease activity. Urea and ammonium nitrogen were not utilized as sole nitrogen sources by cocci, but some diphtheroids used these compounds for nitrogen. The majority of the cocci and diphtheroids were nutritionally fastidious and required amino-nitrogen for growth. In addition, some strains required vitamins and other unidentified metabolites found in yeast extract. These requirements were partially related to the cutaneous site from which the cocci or diphtheroids were isolated. Certain gram-negative bacilli degraded uric acid and utilized urate or its degradation products as nitrogen sources. Images PMID:4911442

Smith, Rodney F.

1970-01-01

287

Where Bacteria and Languages Concur  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Genetic data from human gastric bacteria provide independent support for a linguistic analysis of Pacific population dispersals.

Colin Renfrew (University of Cambridge; McDonald Institute for Archaeological Research)

2009-01-23

288

Geobiology of marine magnetotactic bacteria  

E-print Network

Magnetotactic bacteria (MTB) biomineralize intracellular membrane-bound crystals of magnetite (Fe3O4) or greigite (Fe3S4), and are abundant in the suboxic to anoxic zones of stratified marine environments worldwide. Their ...

Simmons, Sheri Lynn

2006-01-01

289

Diversity of Antibiotic-Active Bacteria Associated with the Brown Alga Laminaria saccharina from the Baltic Sea  

Microsoft Academic Search

Bacteria associated with the marine macroalga Laminaria saccharina, collected from the Kiel Fjord (Baltic Sea, Germany), were isolated and tested for antimicrobial activity. From a total of\\u000a 210 isolates, 103 strains inhibited the growth of at least one microorganism from the test panel including Gram-negative and\\u000a Gram-positive bacteria as well as a yeast. Most common profiles were the inhibition of

Jutta Wiese; Vera Thiel; Kerstin Nagel; Tim Staufenberger; Johannes F. Imhoff

2009-01-01

290

Magnetotactic bacteria for cancer therapy.  

PubMed

Cancer is characterized by anomalous cell growth. Conventional therapies face many challenges and hence alternative treatment methods are in great demand. In addition, nature offers the best inspiration and recently many therapies of natural origin have proved multi-targeted, multi-staged, and a multi-component mode of action against cancer. Magnetotactic bacteria and magnetosomes-based treatment methods are among them. Present paper reviews various routes by which magnetotactic bacteria and magnetosomes contribute to cancer therapy. PMID:25388453

Mathuriya, Abhilasha S

2015-03-01

291

MICROBIOLOGY: How Bacteria Respire Minerals  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required: Some bacteria respire minerals; that is, they harvest energy from minerals through using them as electron acceptors. Many details of this respiration process have remained obscure. In her Perspective, Newman highlights the study by Lower et al., who have used a customized atomic force microscope to observe bacteria during mineral respiration.

Dianne K. Newman (California Institute of Technology; Division of Geological and Planetary Sciences)

2001-05-18

292

In Vitro Activity of TD-1792, a Multivalent Glycopeptide-Cephalosporin Antibiotic, against 377 Strains of Anaerobic Bacteria and 34 Strains of Corynebacterium Species  

PubMed Central

TD-1792 is a multivalent glycopeptide-cephalosporin heterodimer antibiotic with potent activity against Gram-positive bacteria. We tested TD-1792 against 377 anaerobes and 34 strains of Corynebacterium species. Against nearly all Gram-positive strains, TD-1792 had an MIC90 of 0.25 ?g/ml and was typically 3 to 7 dilutions more active than vancomycin and daptomycin. PMID:22290981

Citron, Diane M.; Warren, Yumi A.; Goldstein, Ellie J. C.

2012-01-01

293

Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms.  

PubMed

Biofunctionalized gold nanoparticles (AuNPs) play an important role in design and development of nanomedicine. Synthesis of AuNPs from biogenic materials is environmentally benign and possesses high bacterial inhibition and bactericidal properties. In the present study, blue green alga Spirulina platensis protein mediated synthesis of AuNPs and its antibacterial activity against Gram positive bacteria is discussed. AuNPs were characterized using Ultraviolet-visible (UV-vis) spectroscopy, Fluorescence spectroscopy, Fourier Transform-Infrared (FTIR) spectroscopy, Raman spectroscopy, High Resolution-Transmission Electron Microscopy (HR-TEM) and Energy Dispersive X-ray analysis (EDAX). Stable, well defined AuNPs of smaller and uniform shape with an average size of ~ 5 nm were obtained. The antibacterial efficacy of protein functionalized AuNPs were tested against Gram positive organisms Bacillus subtilis and Staphylococcus aureus. PMID:25492207

Suganya, K S Uma; Govindaraju, K; Kumar, V Ganesh; Dhas, T Stalin; Karthick, V; Singaravelu, G; Elanchezhiyan, M

2015-02-01

294

SPECTROCHEMICAL ANALYSIS OF INORGANIC ELEMENTS IN BACTERIA.  

PubMed

Rouf, M. A. (Washington State University, Pullman). Spectrochemical analysis of inorganic elements in bacteria. J. Bacteriol. 88:1545-1549. 1964.-Quantitative spectrochemical analyses of inorganic elements in the vegetative cells of Escherichia coli, Sphaerotilus natans, Micrococcus roseus, Bacillus cereus, and the spores of B. cereus were made. The following elements were found to be present in the ash samples: B, Na, Mg, Al, Si, P, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, S, Ag, Sn, Ba, Pb, V, and Mo. These could be divided into major, minor, and trace elements, depending on the relative amounts in the cells. Mg, P, K, and S were considered as the major elements; Ca, Fe, Zn, and, perhaps, Cu and Mn as the minor elements, and the rest as trace elements. Mg concentrations were higher in the cells of the gram-positive M. roseus and B. cereus than in the gram-negative E. coli and S. natans. The latter organism contained 2.6% Fe(2)O(3) (dry weight basis). The vegetative cells of B. cereus were higher in Mg, P, K, Na, Ag, and lower in Si, Ca, Zn, Mn, and Cu than were its spores. PMID:14240935

ROUF, M A

1964-12-01

295

Recovery and Identification of Viable Bacteria Immured in Glacial Ice  

NASA Astrophysics Data System (ADS)

An extraction system has been constructed that melts ice from the interior of ice cores and collects the resulting water aseptically. Using this system, bacteria entrapped in ice cores from different geographic locations, that range in age from 5 to 20,000 years old, have been isolated and characterized. Ice cores from the Guliya ice cap on the Tibetan Plateau (China) contained the highest number of colony-forming units per milliliter (˜180 cfu ml -1) and representatives of many different bacterial species. Much lower numbers of bacteria (>20 cfu ml -1) were recovered from Sajama (Bolivia) ice cores, although in general such nonpolar ice cores contained more culturable bacteria than samples of polar ice, presumably due to the closer proximity of major biological ecosystems. More bacteria were recovered from Late Holocene ice from the Taylor Dome region than from ice of the same age from the Antarctic peninsula or from Greenland. Bacterial isolates were identified, in terms of their closest phylogenetic relatives, by determining small-subunit ribosomal RNA-encoding DNA sequences (16S rDNAs), and most were related to spore-forming Bacillus and Actinomycetes species, or to nonsporulating Gram positive bacteria. The numbers of recoverable bacteria did not correlate directly with the age of the ice, indicating that most bacteria were deposited episodically in snowflakes and/or attached to larger particles of inorganic and organic debris. By identifying the features that facilitate microbial survival within terrestrial ice, extrapolations to the likelihood of microorganisms surviving frozen in water ice on Mars, Europa, or within comets will be improved.

Christner, Brent C.; Mosley-Thompson, Ellen; Thompson, Lonnie G.; Zagorodnov, Victor; Sandman, Kathleen; Reeve, John N.

2000-04-01

296

Gram-Positive Anaerobic Cocci  

PubMed Central

Gram-positive anaerobic cocci (GPAC) are a heterogeneous group of organisms defined by their morphological appearance and their inability to grow in the presence of oxygen; most clinical isolates are identified to species in the genus Peptostreptococcus. GPAC are part of the normal flora of all mucocutaneous surfaces and are often isolated from infections such as deep organ abscesses, obstetric and gynecological sepsis, and intraoral infections. They have been little studied for several reasons, which include an inadequate classification, difficulties with laboratory identification, and the mixed nature of the infections from which they are usually isolated. Nucleic acid studies indicate that the classification is in need of radical revision at the genus level. Several species of Peptostreptococcus have recently been described, but others still await formal recognition. Identification has been based on carbohydrate fermentation tests, but most GPAC are asaccharolytic and use the products of protein degradation for their metabolism; the introduction of commercially available preformed enzyme kits affords a physiologically more appropriate method of identification, which is simple and relatively rapid and can be used in routine diagnostic laboratories. Recent reports have documented the isolation in pure culture of several species, notably Peptostreptococcus magnus, from serious infections. Studies of P. magnus have elucidated several virulence factors which correlate with the site of infection, and reveal some similarities to Staphylococcus aureus. P. micros is a strongly proteolytic species; it is increasingly recognized as an important pathogen in intraoral infections, particularly periodontitis, and mixed anaerobic deep-organ abscesses. Comparison of antibiotic susceptibility patterns reveals major differences between species. Penicillins are the antibiotics of choice, although some strains of P. anaerobius show broad-spectrum ?-lactam resistance. PMID:9457430

Murdoch, D. A.

1998-01-01

297

Bacteria Galore by Sunday at Four  

NSDL National Science Digital Library

This colorful picture book provides an introduction to the world of bacteria – where bacteria are found, what it is and how they spread. While the book is beautiful to look at, this children’s picture book is also full of accurate and interesting facts about bacteria. Author Dr. Mel Rosenberg emphasizes the colors, shapes, sizes, forms, and functions of bacteria.

Mel Rosenberg

298

A poultry-intestinal isolate of Campylobacter jejuni produces a bacteriocin (CUV-3) active against a range of Gram positive bacterial pathogens including Clostridium perfringens  

Technology Transfer Automated Retrieval System (TEKTRAN)

A newly isolated bacteriocin, CUV-3, produced by a poultry cecal isolate of Campylobacter jejuni strain CUV-3 had inhibitory activity against several Gram positive bacteria including Clostridium perfringens (38 strains), Staphylococcus aureus, Staph.epidermidis and Listeria monocytogenes. The pept...

299

Gene replacement of adenylate kinase in the gram-positive thermophile Geobacillus stearothermophilus disrupts adenine nucleotide homeostasis and reduces cell viability  

Microsoft Academic Search

Thermophilic bacteria are of great value for industry and research communities. Unfortunately, the cellular processes and mechanisms of these organisms remain largely understudied. In the present study, we investigate how the inactivation of adenylate kinase (AK) affects the adenine nucleotide homeostasis of a gram-positive moderate thermophile, Geobacillus stearothermophilus strain NUB3621-R. AK plays a major role in the adenine nucleotide homeostasis

Rafael Couñago; Yousif Shamoo

2005-01-01

300

Host-Bacteria Crosstalk at the Dentogingival Junction  

PubMed Central

The dentogingival junction is of crucial importance in periodontal host defense both structurally and functionally. Oral bacteria exert a constant challenge to the host cells and tissues at the dentogingival junction. The host response is set up to eliminate the pathogens by the innate and adaptive defense mechanisms. In health, the commensal bacteria and the host defense mechanisms are in a dynamic steady state. During periodontal disease progression, the dental bacterial plaque, junctional epithelium (JE), inflammatory cells, connective tissue, and bone all go through a series of changes. The tissue homeostasis is turned into tissue destruction and progression of periodontitis. The classical study of Slots showed that in the bacterial plaque, the most remarkable change is the shift from gram-positive aerobic and facultatively anaerobic flora to a predominantly gram-negative and anaerobic flora. This has been later confirmed by several other studies. Furthermore, not only the shift of the bacterial flora to a more pathogenic one, but also bacterial growth as a biofilm on the tooth surface, allows the bacteria to communicate with each other and exert their virulence aimed at favoring their growth. This paper focuses on host-bacteria crosstalk at the dentogingival junction and the models studying it in vitro. PMID:22899931

Pöllänen, M. T.; Laine, M. A.; Ihalin, R.; Uitto, V.-J.

2012-01-01

301

Characteristics of airborne bacteria in Mumbai urban environment.  

PubMed

Components of biological origin constitute small but a significant proportion of the ambient airborne particulate matter (PM). However, their diversity and role in proinflammatory responses of PM are not well understood. The present study characterizes airborne bacterial species diversity in Mumbai City and elucidates the role of bacterial endotoxin in PM induced proinflammatory response in ex vivo. Airborne bacteria and endotoxin samples were collected during April-May 2010 in Mumbai using six stage microbial impactor and biosampler. The culturable bacterial species concentration was measured and factors influencing the composition were identified by principal component analysis (PCA). The biosampler samples were used to stimulate immune cells in whole blood assay. A total of 28 species belonging to 17 genera were identified. Gram positive and spore forming groups of bacteria dominated the airborne culturable bacterial concentration. The study indicated the dominance of spore forming and human or animal flora derived pathogenic/opportunistic bacteria in the ambient air environment. Pathogenic and opportunistic species of bacteria were also present in the samples. TNF-? induction by PM was reduced (35%) by polymyxin B pretreatment and this result was corroborated with the results of blocking endotoxin receptor cluster differentiation (CD14). The study highlights the importance of airborne biological particles and suggests need of further studies on biological characterization of ambient PM. PMID:24815556

Gangamma, S

2014-08-01

302

Vancomycin-Resistant Gram-Positive Cocci Isolated from the Saliva of Wild Songbirds  

PubMed Central

We analyzed highly vancomycin-resistant Gram-positive bacteria isolated from the saliva of migratory songbirds captured, sampled, and released from a birdbanding station in western Kansas. Individual bacterial isolates were identified by partial 16S rRNA sequencing. Most of the bacteria in this study were shown to be Staphylococcus succinus with the majority being isolated from the American Robin. Some of these bacteria were shown to carry vanA, vanB, and vanC vancomycin-resistance genes and have the ability to form biofilms. One of the van gene-carrying isolates is also coagulase positive, which is normally considered a virulence factor. Other organisms isolated included Staphylococcus saprophyticus as well as Enterococcus gallinarum. Given the wide range of the American Robin and ease of horizontal gene transfer between Gram-positive cocci, we postulate that these organisms could serve as a reservoir of vancomycin-resistance genes capable of transferring to human pathogens. PMID:23224296

Ishihara, Shingo; Bitner, Jessica J.; Farley, Greg H.

2014-01-01

303

Inducible bacteriophages from ruminal bacteria.  

PubMed Central

The incidence of temperate bacteriophage in a wide range of ruminal bacteria was investigated by means of induction with mitomycin C. Supernatant liquid from treated cultures was examined for phagelike particles by using transmission electron microscopy. Of 38 ruminal bacteria studied, nine organisms (23.7%) representing five genera (Eubacteria, Bacteroides, Butyrivibrio, Ruminococcus, and Streptococcus) produced phagelike particles. Filamentous particles from Butyrivibrio fibrisolvens are the first of this morphological type reported from ruminal bacteria. All of the other particles obtained possessed polyhedral heads and long, noncontractile tails (group B-type phage). The limited range of morphological types produced by mitomycin C induction cannot yet account for the much wider range of types found in ruminal contents by direct examination. The presence of viral genetic material in a significant percentage of the bacteria tested, as well as in a range of different genera, indicates that viral genetic material may be a normal constituent of the genome of appreciable numbers of ruminal bacteria. Images PMID:2504111

Klieve, A V; Hudman, J F; Bauchop, T

1989-01-01

304

Inducible bacteriophages from ruminal bacteria.  

PubMed

The incidence of temperate bacteriophage in a wide range of ruminal bacteria was investigated by means of induction with mitomycin C. Supernatant liquid from treated cultures was examined for phagelike particles by using transmission electron microscopy. Of 38 ruminal bacteria studied, nine organisms (23.7%) representing five genera (Eubacteria, Bacteroides, Butyrivibrio, Ruminococcus, and Streptococcus) produced phagelike particles. Filamentous particles from Butyrivibrio fibrisolvens are the first of this morphological type reported from ruminal bacteria. All of the other particles obtained possessed polyhedral heads and long, noncontractile tails (group B-type phage). The limited range of morphological types produced by mitomycin C induction cannot yet account for the much wider range of types found in ruminal contents by direct examination. The presence of viral genetic material in a significant percentage of the bacteria tested, as well as in a range of different genera, indicates that viral genetic material may be a normal constituent of the genome of appreciable numbers of ruminal bacteria. PMID:2504111

Klieve, A V; Hudman, J F; Bauchop, T

1989-06-01

305

Isolation and characterization of endophytic bacteria from wild and traditionally cultivated rice varieties  

Microsoft Academic Search

Endophytic bacteria were isolated from surface-sterilized stems, seeds, and leaf sheaths of wild and traditionally cultivated rice varieties. Phylogenetic analyses based on 16S rDNA revealed a wide divergence among the isolates. However, the most frequently isolated groups were Methylobacterium sp. in the ?-subdivision of Proteobacteria, and Curtobacterium sp. in the high G+ C Gram-positive group. Various phenotypic traits that are

Adel Elbeltagy; Kiyo Nishioka; Hisa Suzuki; Tadashi Sato; Yo-Ichiro Sato; Hisao Morisaki; Hisayuki Mitsui; Kiwamu Minamisawa

2000-01-01

306

Selective depletion of bacteria alters but does not eliminate odors of individuality in Rattus norvegicus  

Microsoft Academic Search

To determine if odors of individuality are influenced by the removal of Gram-negative or Gram-positive gut bacteria, Long–Evans rats were trained in an operant olfactometer to discriminate between the odors of two individual conspecifics and their operant responses to three different odors in randomly presented probe trials were analyzed. Significantly more responses were made to the probe odors from two

Heather MacIntosh Schellinck; Richard E Brown

2000-01-01

307

Cadmium Ion Biosorption by the Thermophilic Bacteria Geobacillus stearothermophilus and G. thermocatenulatus  

Microsoft Academic Search

This study reports surface complexation models (SCMs) for quantifying metal ion adsorption by thermo- philic microorganisms. In initial cadmium ion toxicity tests, members of the genus Geobacillus displayed the highest tolerance to CdCl2 (as high as 400 to 3,200 M). The thermophilic, gram-positive bacteria Geobacillus stearothermophilus and G. thermocatenulatus were selected for further electrophoretic mobility, potentiometric titration, and Cd2 adsorption

Adrian Hetzer; Christopher J. Daughney; Hugh W. Morgan

2006-01-01

308

Metabolism of Linoleic Acid by Human Gut Bacteria: Different Routes for Biosynthesis of Conjugated Linoleic Acid?  

PubMed Central

A survey of 30 representative strains of human gram-positive intestinal bacteria indicated that Roseburia species were among the most active in metabolizing linoleic acid (cis-9,cis-12-18:2). Different Roseburia spp. formed either vaccenic acid (trans-11-18:1) or a 10-hydroxy-18:1; these compounds are precursors of the health-promoting conjugated linoleic acid cis-9,trans-11-18:2 in human tissues and the intestine, respectively. PMID:17209019

Devillard, Estelle; McIntosh, Freda M.; Duncan, Sylvia H.; Wallace, R. John

2007-01-01

309

Mechanisms of the resistance and tolerance to beta-lactam and glycopeptide antibiotics in pathogenic gram-positive cocci.  

PubMed

Beta-lactams are the most frequently used antimicrobials in combating infections. In the case of gram-positive bacteria resistant to beta-lactams, glycopeptides are the first choice. The occurrence, mechanisms and genetic background of the resistance of pathogenic staphylococci, streptococci and enterococci to beta-lactam and glycopeptide antibiotics were discussed. The resistances to well-established antimicrobials, as well as new agents (ceftobiprole, oritavancin, telavancin, dalbavancin) were taken into consideration in the text. PMID:20205634

Mlynarczyk, A; Mlynarczyk, B; Kmera-Muszynska, M; Majewski, S; Mlynarczyk, G

2009-11-01

310

Mechanical Consequences of Cell-Wall Turnover in the Elongation of a Gram-Positive Bacterium  

PubMed Central

A common feature of walled organisms is their exposure to osmotic forces that challenge the mechanical integrity of cells while driving elongation. Most bacteria rely on their cell wall to bear osmotic stress and determine cell shape. Wall thickness can vary greatly among species, with Gram-positive bacteria having a thicker wall than Gram-negative bacteria. How wall dimensions and mechanical properties are regulated and how they affect growth have not yet been elucidated. To investigate the regulation of wall thickness in the rod-shaped Gram-positive bacterium Bacillus subtilis, we analyzed exponentially growing cells in different media. Using transmission electron and epifluorescence microscopy, we found that wall thickness and strain were maintained even between media that yielded a threefold change in growth rate. To probe mechanisms of elongation, we developed a biophysical model of the Gram-positive wall that balances the mechanical effects of synthesis of new material and removal of old material through hydrolysis. Our results suggest that cells can vary their growth rate without changing wall thickness or strain by maintaining a constant ratio of synthesis and hydrolysis rates. Our model also indicates that steady growth requires wall turnover on the same timescale as elongation, which can be driven primarily by hydrolysis rather than insertion. This perspective of turnover-driven elongation provides mechanistic insight into previous experiments involving mutants whose growth rate was accelerated by the addition of lysozyme or autolysin. Our approach provides a general framework for deconstructing shape maintenance in cells with thick walls by integrating wall mechanics with the kinetics and regulation of synthesis and turnover. PMID:23746506

Misra, Gaurav; Rojas, Enrique R.; Gopinathan, Ajay; Huang, Kerwyn Casey

2013-01-01

311

Antimicrobial Photodynamic Therapy to Kill Gram-negative Bacteria  

PubMed Central

Antimicrobial photodynamic therapy (PDT) or photodynamic inactivation (PDI) is a new promising strategy to eradicate pathogenic microorganisms such as Gram-positive and Gram-negative bacteria, yeasts and fungi. The search for new approaches that can kill bacteria but do not induce the appearance of undesired drug-resistant strains suggests that PDT may have advantages over traditional antibiotic therapy. PDT is a non-thermal photochemical reaction that involves the simultaneous presence of visible light, oxygen and a dye or photosensitizer (PS). Several PS have been studied for their ability to bind to bacteria and efficiently generate reactive oxygen species (ROS) upon photostimulation. ROS are formed through type I or II mechanisms and may inactivate several classes of microbial cells including Gram-negative bacteria such as Pseudomonas aeruginosa, which are typically characterized by an impermeable outer cell membrane that contains endotoxins and blocks antibiotics, dyes, and detergents, protecting the sensitive inner membrane and cell wall. This review covers significant peer-reviewed articles together with US and World patents that were filed within the past few years and that relate to the eradication of Gram-negative bacteria via PDI or PDT. It is organized mainly according to the nature of the PS involved and includes natural or synthetic food dyes; cationic dyes such as methylene blue and toluidine blue; tetrapyrrole derivatives such as phthalocyanines, chlorins, porphyrins, chlorophyll and bacteriochlorophyll derivatives; functionalized fullerenes; nanoparticles combined with different PS; other formulations designed to target PS to bacteria; photoactive materials and surfaces; conjugates between PS and polycationic polymers or antibodies; and permeabilizing agents such as EDTA, PMNP and CaCl2. The present review also covers the different laboratory animal models normally used to treat Gram-negative bacterial infections with antimicrobial PDT. PMID:23550545

Sperandio, Felipe F; Huang, Ying-Ying; Hamblin, Michael R

2013-01-01

312

Commensal bacteria and cutaneous immunity.  

PubMed

The skin is the human body's largest organ and is home to a diverse and complex variety of innate and adaptive immune functions that protect against pathogenic invasion. Recent studies have demonstrated that cutaneous commensal bacteria modulated the host immune system. For example, Staphylococcus epidermidis, a skin commensal bacterium, has been demonstrated to induce cutaneous interferon (IFN)-?- and interleukin (IL)-17A-producing T cells. In addition, cutaneous microbiota changes occur in the chronic inflammatory skin disorders, such as atopic dermatitis, and may influence the activity of skin diseases. In this article, we will review the recent findings related to the interactions of the commensal bacteria with skin homeostasis and discuss the role of the dysbiosis of these bacteria in the pathogenesis of skin diseases. PMID:25326105

Nakamizo, Satoshi; Egawa, Gyohei; Honda, Tetsuya; Nakajima, Saeko; Belkaid, Yasmine; Kabashima, Kenji

2015-01-01

313

Genetic transfer in acidophilic bacteria  

SciTech Connect

There is increasing interest in the use of microorganisms to recover metals from ores, as well as to remove sulfur from coal. These so-called bioleaching processes are mediated by a number of bacteria. The best-studied of these organisms are acidophiles including Thiobacillus and Acidiphilium species. Our laboratory has focused on developing genetic strategies to allow the manipulation of acidophilic bacteria to improve and augment their utility in large scale operations. We have recently been successful in employing conjugation for interbacterial transfer of genetic information, as well as in directly transforming Acidiphilium by use of electroporation. We are now testing the properties of IncPl, IncW and IncQ plasmid vectors in Acidiphilium to determine their relative usefulness in routine manipulation of acidophiles and transfer between organisms. This study also allows us to determine the natural ability of these bacteria to transfer genetic material amongst themselves in their particular environment. 21 refs., 3 figs., 2 tabs.

Roberto, F.F.; Glenn, A.W.; Bulmer, D.; Ward, T.E.

1990-01-01

314

Antifungal activity of rhizospheric bacteria.  

PubMed

Fluorescent Pseudomonad spp. were isolated from the rhizosphere of potato plants (Algeria) by serial dilutions of rhizosphere soils on Kings B medium and were tested for their antifungal activity. The antifungal activity of the Pseudomonas isolated from Potatoes rhizosphere was tested against Pythium ultimum, Rhizoctonia solani and Fusarium oxysporum in dual culture with bacteria on PDA. The Petri dish was divided into tow, on one the bacteria was spread and on the opposite side fungal plugs were inoculated and incubated for one week. Fourteen bacteria were isolated; only one isolate inhibited the growth of Pythium ultimum, Rhizoctonia solani, Fusarium solani; Fusarium oxysporum f.sp. albedinis and Fusarium oxysporum f. sp. Lycopersici with inhibition zones of 39.9, 33.7, 30.8, 19.9 and 22.5 mm respectively. PMID:21534477

Mezaache, S; Guechi, A; Zerroug, M M; Strange, R N; Nicklin, J

2010-01-01

315

Envisaging bacteria as phage targets  

PubMed Central

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

Abedon, Stephen T.

2011-01-01

316

A novel, nested, multiplex, real-time PCR for detection of bacteria and fungi in blood  

PubMed Central

Background The study describes the application of the PCR method for the simultaneous detection of DNA of Gram-negative bacteria, Gram-positive bacteria, yeast fungi and filamentous fungi in blood and, thus, a whole range of microbial etiological agents that may cause sepsis. Material for the study was sterile blood inoculated with four species of microorganisms (Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillus fumigatus) and blood collected from patients with clinical symptoms of sepsis. The developed method is based on nested-multiplex real-time PCR . Results Analysis of the obtained data shows that sensitivity of nested-multiplex real-time PCR remained at the level of 101 CFU/ml for each of the four studied species of microorganisms and the percentage of positive results of the examined blood samples from the patients was 70% and 19% for the microbiological culture method. The designed primers correctly typed the studied species as belonging to the groups of Gram-positive bacteria, Gram-negative bacteria, yeast fungi, or filamentous fungi. Conclusions Results obtained by us indicated that the designed PCR methods: (1) allow to detect bacteria in whole blood samples, (2) are much more sensitive than culture method, (3) allow differentiation of the main groups of microorganisms within a few hours. PMID:24893651

2014-01-01

317

Chip-based in situ hybridization for identification of bacteria from the human microbiome.  

SciTech Connect

The emerging field of metagenomics seeks to assess the genetic diversity of complex mixed populations of bacteria, such as those found at different sites within the human body. A single person's mouth typically harbors up to 100 bacterial species, while surveys of many people have found more than 700 different species, of which {approx}50% have never been cultivated. In typical metagenomics studies, the cells themselves are destroyed in the process of gathering sequence information, and thus the connection between genotype and phenotype is lost. A great deal of sequence information may be generated, but it is impossible to assign any given sequence to a specific cell. We seek non-destructive, culture-independent means of gathering sequence information from selected individual cells from mixed populations. As a first step, we have developed a microfluidic device for concentrating and specifically labeling bacteria from a mixed population. Bacteria are electrophoretically concentrated against a photopolymerized membrane element, and then incubated with a specific fluorescent label, which can include antibodies as well as specific or non-specific nucleic acid stains. Unbound stain is washed away, and the labeled bacteria are released from the membrane. The stained cells can then be observed via epifluorescence microscopy, or counted via flow cytometry. We have tested our device with three representative bacteria from the human microbiome: E. coli (gut, Gram-negative), Lactobacillus acidophilus (mouth, Gram-positive), and Streptococcus mutans (mouth, Gram-positive), with results comparable to off-chip labeling techniques.

Light, Yooli Kim; Meagher, Robert J.; Singh, Anup K.; Liu, Peng

2010-11-01

318

New and Rare Carotenoids Isolated from Marine Bacteria and Their Antioxidant Activities  

PubMed Central

Marine bacteria have not been examined as extensively as land bacteria. We screened carotenoids from orange or red pigments-producing marine bacteria belonging to rare or novel species. The new acyclic carotenoids with a C30 aglycone, diapolycopenedioc acid xylosylesters A–C and methyl 5-glucosyl-5,6-dihydro-apo-4,4?-lycopenoate, were isolated from the novel Gram-negative bacterium Rubritalea squalenifaciens, which belongs to phylum Verrucomicrobia, as well as the low-GC Gram-positive bacterium Planococcus maritimus strain iso-3 belonging to the class Bacilli, phylum Firmicutes, respectively. The rare monocyclic C40 carotenoids, (3R)-saproxanthin and (3R,2?S)-myxol, were isolated from novel species of Gram-negative bacteria belonging to the family Flavobacteriaceae, phylum Bacteroidetes. In this review, we report the structures and antioxidant activities of these carotenoids, and consider relationships between bacterial phyla and carotenoid structures. PMID:24663119

Shindo, Kazutoshi; Misawa, Norihiko

2014-01-01

319

New and rare carotenoids isolated from marine bacteria and their antioxidant activities.  

PubMed

Marine bacteria have not been examined as extensively as land bacteria. We screened carotenoids from orange or red pigments-producing marine bacteria belonging to rare or novel species. The new acyclic carotenoids with a C?? aglycone, diapolycopenedioc acid xylosylesters A-C and methyl 5-glucosyl-5,6-dihydro-apo-4,4'-lycopenoate, were isolated from the novel Gram-negative bacterium Rubritalea squalenifaciens, which belongs to phylum Verrucomicrobia, as well as the low-GC Gram-positive bacterium Planococcus maritimus strain iso-3 belonging to the class Bacilli, phylum Firmicutes, respectively. The rare monocyclic C?? carotenoids, (3R)-saproxanthin and (3R,2'S)-myxol, were isolated from novel species of Gram-negative bacteria belonging to the family Flavobacteriaceae, phylum Bacteroidetes. In this review, we report the structures and antioxidant activities of these carotenoids, and consider relationships between bacterial phyla and carotenoid structures. PMID:24663119

Shindo, Kazutoshi; Misawa, Norihiko

2014-03-01

320

Emerging issues in antimicrobial resistance of bacteria from food-producing animals.  

PubMed

ABSTRACT? During the last decade, antimicrobial resistance in bacteria from food-producing animals has become a major research topic. In this review, different emerging resistance properties related to bacteria of food-producing animals are highlighted. These include: extended-spectrum ?-lactamase-producing Enterobacteriaceae; carbapenemase-producing bacteria; bovine respiratory tract pathogens, such as Pasteurella multocida and Mannheimia haemolytica, which harbor the multiresistance mediating integrative and conjugative element ICEPmu1; Gram-positive and Gram-negative bacteria that carry the multiresistance gene cfr; and the occurrence of numerous novel antimicrobial resistance genes in livestock-associated methicillin-resistant Staphylococcus aureus. The emergence of the aforementioned resistance properties is mainly based on the exchange of mobile genetic elements that carry the respective resistance genes. PMID:25812464

Michael, Geovana Brenner; Freitag, Christin; Wendlandt, Sarah; Eidam, Christopher; Feßler, Andrea T; Lopes, Graciela Volz; Kadlec, Kristina; Schwarz, Stefan

2015-03-01

321

Spatial relationships between bacteria and localized corrosion  

SciTech Connect

Spatial relationships between bacteria and polarization were examined using microbiological and surface analytical techniques. Corrosion products produced by well-established artificial crevices in 304 stainless steel in abiotic seawater were associated with large numbers of bacteria after brief exposures to natural seawater. The presence of bacteria did not alter the distribution or composition of the corrosion products. Cathodic polarization increased the number of viable marine bacteria and extracellular debris on 304 stainless steel. Bacterial colonization and metabolism can fix anodes and cathodes; however, abiotic polarization can influence the number and types of bacteria associated with the surface. Spatial relationships between bacteria and localized corrosion cannot independently be interpreted as causal.

Little, B.J.; Wagner, P.A.; Hart, K.R.; Ray, R.I. [Naval Research Lab., Stennis Space Center, MS (United States)

1996-12-01

322

Biopreservation by lactic acid bacteria  

Microsoft Academic Search

Biopreservation refers to extended storage life and enhanced safety of foods using the natural microflora and (or) their antibacterial products. Lactic acid bacteria have a major potential for use in biopreservation because they are safe to consume and during storage they naturally dominate the microflora of many foods. In milk, brined vegetables, many cereal products and meats with added carbohydrate,

Michael E. Stiles

1996-01-01

323

Role of Bacteria in Oncogenesis  

PubMed Central

Summary: Although scientific knowledge in viral oncology has exploded in the 20th century, the role of bacteria as mediators of oncogenesis has been less well elucidated. Understanding bacterial carcinogenesis has become increasingly important as a possible means of cancer prevention. This review summarizes clinical, epidemiological, and experimental evidence as well as possible mechanisms of bacterial induction of or protection from malignancy. PMID:20930075

Chang, Alicia H.; Parsonnet, Julie

2010-01-01

324

Recognition of Bacteria by Inflammasomes  

E-print Network

Recognition of Bacteria by Inflammasomes Jakob von Moltke, Janelle S. Ayres, Eric M. Kofoed, Joseph immunity, pyroptosis Abstract Inflammasomes are cytosolic multiprotein complexes that assem- ble in response to a variety of infectious and noxious insults. Inflammasomes play a critical role

Vance,. Russell

325

Hydrocarbon degradation by antarctic bacteria  

SciTech Connect

Bacterial cultures obtained from sediment samples collected during a trial oil spill experiment conducted at Airport beach, Eastern Antarctica were selectively enriched for n-alkane-degrading and phenanthrenedegrading bacteria. Samples were collected from a control site and sites treated with different hydrocarbon mixtures - Special Antarctic blend (SAB), BP-Visco and orange roughy oils. One set of replicate sites was also treated with water from Organic Lake which had previously been shown to contain hydrocarbon-degrading bacteria. No viable bacteria were obtained from samples collected from sites treated with orange roughy oil. Extensive degradation of n-alkanes by enrichment cultures obtained from sites treated with SAB and BP-Visco occurred at both 25{degrees}C and 10{degrees}C. Extensive degradation of phenanthrene also occurred in enrichment cultures from these sites grown at 25{degrees}C. Concurrent increases of polar lipid in these cultures were also observed. The presence of 1,4-naphthaquinone and 1-naphthol during the growth of the cultures on phenanthrene is unusual and warrants further investigation of the mechanism of phenanthrene-degradation by these Antarctic bacteria.

Cavanagh, J.A.E.; Nichols, P.D.; McMeekin, T.A.; Franzmann, P.D. [Univ. of Tasmania (Australia)] [and others

1996-12-31

326

Psychrophilic Bacteria—A Review  

Microsoft Academic Search

su iv( :M:ARY Psychrophilie bacteria grow at a relatively rapid rate at or below 45 ° F. (7.2 ° C.) and are capable of forming visible colonies on plates incubated for ten days at 7 ~+ 0.5 C. Since psychrophiles grow at refrigeration temperatures, they are primarily responsible for limiting the keeping' quality of milk and many dairy products in

Lloyd D. Witter

1961-01-01

327

The sulphate-reducing bacteria  

Microsoft Academic Search

This monograph surveys knowledge about an unusual and little-studied group of microbes, bringing together information that has hitherto been widely scattered throughout the scientific literature. The sulphate-reducing bacteria cannot grow in air; they respire sulphates instead of oxygen and are difficult to isolate and study. Nevertheless, much progress has been made in recent years and has revealed novelties of biochemistry

1984-01-01

328

Manipulating Genetic Material in Bacteria  

NASA Technical Reports Server (NTRS)

Lisa Crawford, a graduate research assistant from the University of Toledo, works with Laurel Karr of Marshall Space Flight Center (MSFC) in the molecular biology laboratory. They are donducting genetic manipulation of bacteria and yeast for the production of large amount of desired protein. Photo credit: NASA/Marshall Space Flight Center (MSFC)

1998-01-01

329

Glycopeptide resistance in gram-positive cocci: a review.  

PubMed

Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens in the past two decades all over the world and have seriously limited the choices available to clinicians for treating infections caused by these agents. Methicillin-resistant Staphylococcus aureus, perhaps the most notorious among the nosocomial pathogens, was till recently susceptible to vancomycin and the other glycopeptides. Emergence of vancomycin nonsusceptible strains of S. aureus has led to a worrisome scenario where the options available for treating serious infections due to these organisms are very limited and not well evaluated. Vancomycin resistance in clinically significant isolates of coagulase-negative staphylococci is also on the rise in many setups. This paper aims to highlight the genetic basis of vancomycin resistance in Enterococcus species and S. aureus. It also focuses on important considerations in detection of vancomycin resistance in these gram-positive bacteria. The problem of glycopeptide resistance in clinical isolates of coagulase-negative staphylococci and the phenomenon of vancomycin tolerance seen in some strains of Streptococcus pneumoniae has also been discussed. Finally, therapeutic options available and being developed against these pathogens have also found a mention. PMID:22778729

Sujatha, S; Praharaj, Ira

2012-01-01

330

Non-classical protein secretion in bacteria  

PubMed Central

Background We present an overview of bacterial non-classical secretion and a prediction method for identification of proteins following signal peptide independent secretion pathways. We have compiled a list of proteins found extracellularly despite the absence of a signal peptide. Some of these proteins also have known roles in the cytoplasm, which means they could be so-called "moon-lightning" proteins having more than one function. Results A thorough literature search was conducted to compile a list of currently known bacterial non-classically secreted proteins. Pattern finding methods were applied to the sequences in order to identify putative signal sequences or motifs responsible for their secretion. We have found no signal or motif characteristic to any majority of the proteins in the compiled list of non-classically secreted proteins, and conclude that these proteins, indeed, seem to be secreted in a novel fashion. However, we also show that the apparently non-classically secreted proteins are still distinguished from cellular proteins by properties such as amino acid composition, secondary structure and disordered regions. Specifically, prediction of disorder reveals that bacterial secretory proteins are more structurally disordered than their cytoplasmic counterparts. Finally, artificial neural networks were used to construct protein feature based methods for identification of non-classically secreted proteins in both Gram-positive and Gram-negative bacteria. Conclusion We present a publicly available prediction method capable of discriminating between this group of proteins and other proteins, thus allowing for the identification of novel non-classically secreted proteins. We suggest candidates for non-classically secreted proteins in Escherichia coli and Bacillus subtilis. The prediction method is available online. PMID:16212653

Bendtsen, Jannick D; Kiemer, Lars; Fausbøll, Anders; Brunak, Søren

2005-01-01

331

Zinc isotope fractionation during surface adsorption by bacteria  

NASA Astrophysics Data System (ADS)

The cycling and transport of zinc (Zn) in natural waters is partly controlled by its adsorption and uptake by bacterial communities. These reactions are reflected in changes in the ratios of stable Zn isotopes; however, the magnitudes and directions of these changes are largely unconstrained. In the current work, we attempt to define Zn isotope fractionation factors for bacteria-Zn interactions by performing adsorption experiments with representative Gram-positive (Bacillus subtilis) and Gram-negative (Pseudomonas mendocina) bacteria. Experiments included, (1) pH-dependent adsorption using differing bacteria:Zn ratios, (2) Zn loading at constant pH, and (3) kinetics and reversibility experiments. Results indicate that Zn adsorption is fully reversible for both bacterial species. Moreover, under the same experimental conditions both bacterial species adsorbed Zn to similar extents. Initial isotopic analysis (using a Nu Instruments MC-ICP-MS) demonstrates that, as the extent of adsorption increases, the heavier Zn isotopes are preferentially incorporated as bacterial-surface complexes. Under conditions of low bacteria:Zn ratio, the ?66Znbacteria-solution was about 0.3% for both bacterial species. This separation factor is similar to that found in other studies involving the complexation of Zn with biologic or organic components. For example, the complexation of Zn with Purified Humic Acid (PHA) resulted in a ?66ZnPHA-solution of +0.24% [1], and sorption of Zn onto two separate diatom species resulted in ?66Znsolid-solution of +0.43% and +0.27%, respectively [2]. These results suggest that Zn complexation with functional groups common to bacteria and natural organic matter may be a process that universally incorporates the heavier Zn isotopes. Our current work is focused on quantifying Zn isotope fractionation during metabolic incorporation by separating this effect from surface adsorption reactions. [1] Jouvin et al., (2009) Environ. Sci. Technol., 43(15) 5747-5754. [2] Gélabert et al., (2006) Geochim. Cosmochim. Acta 70(4) 839-857.

Kafantaris, F. A.; Borrok, D. M.

2011-12-01

332

Bacteriophage endolysins: A novel anti-infective to control Gram-positive pathogens  

PubMed Central

Endolysins (or lysins) are highly evolved enzymes produced by bacteriophage (phage for short) to digest the bacterial cell wall for phage progeny release. In Gram-positive bacteria, small quantities of purified recombinant lysin added externally results in immediate lysis causing log-fold death of the target bacterium. Lysins have been used successfully in a variety of animal models to control pathogenic antibiotic-resistant bacteria found on mucosal surfaces and infected tissues. Their specificity for the pathogen without disturbing the normal flora, the low chance of bacterial resistance, and their ability to kill colonizing pathogens on mucosal surfaces, a capacity previously unavailable, make them ideal anti-infectives in an age of mounting resistance. Here we review the current literature showing the effectiveness of these enzymes in controlling a variety of infections. PMID:20452280

Fischetti, Vincent A.

2010-01-01

333

Bacteria, Yeast and Chemicals on Human Skin  

MedlinePLUS Videos and Cool Tools

... the lower right-hand corner of the player. Bacteria, Yeast and Chemicals on Human Skin HealthDay April ... the distribution and quantity of metabolites, peptides, lipids, bacteria, yeast, proteins, chemicals and more. As expected, many ...

334

Killer Pigments in Bacteria: An Ecological Nightmare.  

ERIC Educational Resources Information Center

Describes an alternative to teaching ecology by using bacteria to test competitor survival. Students observe a time-dependent selective killing of other unrelated bacteria by Pseudomonas aeruginosa. (SAH)

Benathen, Isaiah A.; Saccardi, Marion

2000-01-01

335

New Antibiotic May Combat Resistant Bacteria  

MedlinePLUS

... please enable JavaScript. New Antibiotic May Combat Resistant Bacteria Teixobactin shows promise in early experiments, researchers say (* ... that could prove valuable in fighting disease-causing bacteria that no longer respond to older, more frequently ...

336

Barbecue Bliss: Keeping Bacteria at Bay  

MedlinePLUS

... Home For Consumers Consumer Updates Barbecue Bliss: Keeping Bacteria at Bay Search the Consumer Updates Section Get ... your list. Summer brings out barbecue grills—and bacteria, which multiply in food faster in warm weather ...

337

Antagonism of Lactic Acid Bacteria against Phytopathogenic Bacteria  

PubMed Central

A variety of lactic acid bacteria, isolated from plant surfaces and plant-associated products, were found to be antagonistic to test strains of the phytopathogens Xanthomonas campestris, Erwinia carotovora, and Pseudomonas syringae. Effective “in vitro” inhibition was found both on agar plates and in broth cultures. In pot trials, treatment of bean plants with a Lactobacillus plantarum strain before inoculation with P. syringae caused a significant reduction of the disease incidence. Images PMID:16347150

Visser, Ronèl; Holzapfel, Wilhelm H.; Bezuidenhout, Johannes J.; Kotzé, Johannes M.

1986-01-01

338

Distribution and Characterization of Kepone-Resistant Bacteria in the Aquatic Environment  

PubMed Central

Effects of the chlorinated insecticide Kepone on the ecology of Chesapeake Bay and James River bacteria were studied. Kepone-resistant bacteria present in a given environment were found to reflect the degree of fecal and/or high organic pollution of the sampling sites, based on total numbers and generic composition of the populations of Kepone-resistant bacteria. The presence of Kepone-resistant bacteria was found to be correlated (? = 0.01) with total coliforms, fecal coliforms, and total aerobic viable heterotrophic bacteria, but not with Kepone concentration, since Kepone-resistant bacteria were present in locations where Kepone could not be detected by the analytical methods used in this study. Only gram-negative bacteria, predominantly Pseudomonas, Vibrio, and Aeromonas spp., were found to be resistant to ?10 ?g of Kepone per ml. Gram-positive bacteria, i.e., Bacillus and Corynebacterium spp., were generally sensitive to ?0.1 ?g of Kepone per ml. From results of cluster analysis of taxonomic data, we determined that characteristics of Kepone-resistant bacteria included: resistance to pesticides and heavy metals; degradation of oil; positive oxidase and catalase reactions; and nitrate reduction. From results of the ecological and taxonomic analyses, we conclude that Kepone resistance in estuarine bacteria is due to the physicochemical composition of the gram-negative cell wall and not prior exposure to Kepone. Therefore, the presence of Kepone-resistant bacteria cannot serve as an indicator of Kepone contamination in the aquatic environment where gram-negative bacteria are predominant. PMID:6155825

Orndorff, S. A.; Colwell, R. R.

1980-01-01

339

Procalcitonin Levels in Gram-Positive, Gram-Negative, and Fungal Bloodstream Infections  

PubMed Central

Procalcitonin (PCT) can discriminate bacterial from viral systemic infections and true bacteremia from contaminated blood cultures. The aim of this study was to evaluate PCT diagnostic accuracy in discriminating Gram-positive, Gram-negative, and fungal bloodstream infections. A total of 1,949 samples from patients with suspected bloodstream infections were included in the study. Median PCT value in Gram-negative (13.8?ng/mL, interquartile range (IQR) 3.4–44.1) bacteremias was significantly higher than in Gram-positive (2.1?ng/mL, IQR 0.6–7.6) or fungal (0.5?ng/mL, IQR 0.4–1) infections (P < 0.0001). Receiver operating characteristic analysis showed an area under the curve (AUC) for PCT of 0.765 (95% CI 0.725–0.805, P < 0.0001) in discriminating Gram-negatives from Gram-positives at the best cut-off value of 10.8?ng/mL and an AUC of 0.944 (95% CI 0.919–0.969, P < 0.0001) in discriminating Gram-negatives from fungi at the best cut-off of 1.6?ng/mL. Additional results showed a significant difference in median PCT values between Enterobacteriaceae and nonfermentative Gram-negative bacteria (17.1?ng/mL, IQR 5.9–48.5 versus 3.5?ng/mL, IQR 0.8–21.5; P < 0.0001). This study suggests that PCT may be of value to distinguish Gram-negative from Gram-positive and fungal bloodstream infections. Nevertheless, its utility to predict different microorganisms needs to be assessed in further studies. PMID:25852221

Ferranti, Marta; Moretti, Amedeo; Al Dhahab, Zainab Salim; Cenci, Elio; Mencacci, Antonella

2015-01-01

340

Re-engineering bacteria for ethanol production  

DOEpatents

The invention provides recombinant bacteria, which comprise a full complement of heterologous ethanol production genes. Expression of the full complement of heterologous ethanol production genes causes the recombinant bacteria to produce ethanol as the primary fermentation product when grown in mineral salts medium, without the addition of complex nutrients. Methods for producing the recombinant bacteria and methods for producing ethanol using the recombinant bacteria are also disclosed.

Yomano, Lorraine P; York, Sean W; Zhou, Shengde; Shanmugam, Keelnatham; Ingram, Lonnie O

2014-05-06

341

Magnetotactic bacteria and their magnetofossils in sediments  

Microsoft Academic Search

Living magnetotactic bacteria from freshwater environments show, under natural and laboratory conditions, a great variety of morphological appearances. Their magnetosomes vary in number, shape, and size. One species of bacteria yields up to 1000 magnetosomes per cell. Individual particles reach a size of up to 200 nm. As a rule, they form elongated chains. In bacteria which are held under

H. Vali; O. Förster; G. Amarantidis; N. Petersen

1987-01-01

342

Original article Mycorrhization helper bacteria associated  

E-print Network

for soil disinfection before inoculating might be reduced. ectomycorrhizas / bacteria / rhizosphereOriginal article Mycorrhization helper bacteria associated with the Douglas fir-Laccaria laccata could be improved by such mycor- rhization helper bacteria (MHB). The results with T terrestris suggest

Paris-Sud XI, Université de

343

Urine Isn't Free of Bacteria  

MedlinePLUS

... please enable JavaScript. Urine Isn't Free of Bacteria New study links bacteria found in urine in bladder to urinary incontinence (* ... News) -- Though it's commonly believed that urine is bacteria-free, normal urine is not sterile, a new ...

344

Laser-Based Identification of Pathogenic Bacteria  

ERIC Educational Resources Information Center

Bacteria are ubiquitous in our world. From our homes, to our work environment, to our own bodies, bacteria are the omnipresent although often unobserved companions to human life. Physicists are typically untroubled professionally by the presence of these bacteria, as their study usually falls safely outside the realm of our typical domain. In the…

Rehse, Steven J.

2009-01-01

345

3, 765778, 2006 Culturable bacteria in  

E-print Network

BGD 3, 765­778, 2006 Culturable bacteria in Himalayan ice S. Zhang et al. Title Page Abstract Biogeosciences Discussions is the access reviewed discussion forum of Biogeosciences Culturable bacteria Correspondence to: S. Hou (shugui@lzb.ac.cn) 765 #12;BGD 3, 765­778, 2006 Culturable bacteria in Himalayan ice S

Boyer, Edmond

346

Drosophila lifespan enhancement by exogenous bacteria  

E-print Network

Drosophila lifespan enhancement by exogenous bacteria Ted Brummel*, Alisa Ching*, Laurent Seroude with customary procedure. The experiments revealed that the presence of bacteria during the first week of adult life can enhance lifespan, despite unchanged food intake. Later in life, the presence of bacteria can

Seroude, Laurent

347

Bacteria Fate and Movement Dr. Claire Baffaut  

E-print Network

Bacteria Fate and Movement Dr. Claire Baffaut Dr. Jeff Arnold And John Schumacher #12;Foliar Application Die-off/Re-growth Washoff Infiltration Leaching Runoff Surface Application Bacteria Fate Die-off/Re-growth Die-off/Re-growth #12;Movement in runoff and leaching On plants Bact_Plt = GC*Bact_App Bacteria

348

Genetics of Lactic Acid Bacteria  

NASA Astrophysics Data System (ADS)

Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

349

Dissipative shocks behind bacteria gliding.  

PubMed

Gliding is a means of locomotion on rigid substrates used by a number of bacteria, including myxobacteria and cyanobacteria. One of the hypotheses advanced to explain this motility mechanism hinges on the role played by the slime filaments continuously extruded from gliding bacteria. This paper solves, in full, a non-linear mechanical theory that treats as dissipative shocks both the point where the extruded slime filament comes into contact with the substrate, called the filament's foot, and the pore on the bacterium outer surface from where the filament is ejected. I prove that kinematic compatibility for shock propagation requires that the bacterium uniform gliding velocity (relative to the substrate) and the slime ejecting velocity (relative to the bacterium) must be equal, a coincidence that seems to have already been observed. PMID:25332385

Virga, Epifanio G

2014-11-28

350

Viability of bacteria in peatlands  

NASA Astrophysics Data System (ADS)

The viability of bacteria in oligotrofic bogs and fens was determined by the luminescent microscopy method with the help of a two-component fluorescent dye (L7012 LIVE/DEAD). Living bacterial cells were found in the entire peat profiles. Their portion was maximal (up to 60%) in the upper layers and did not exceed 25% in the lower layers. The portion of dead bacterial cells varied from 3 to 19%, and dormant cells constituted 25 to 95% of the total number of bacterial cells. The numbers of dormant cells increased down the profiles irrespectively of the peat type. The portion of nanoforms did not exceed 5% of the total. The cells of the nanoforms, unlike the bacteria of typical sizes, were characterized by their high viability (93-98%).

Bogdanova, O. Yu.; Golovchenko, A. V.; Lysak, L. V.; Glukhova, T. V.; Zvyagintsev, D. G.

2014-04-01

351

Extremophilic Bacteria and Microbial Diversity  

NSDL National Science Digital Library

This online enhancement chapter of Raven and Johnson's Biology, a textbook for undergraduate majors, examines the many prokaryotic organisms that inhabit "extreme environments"–habitats in which some chemical or physical variable(s) differ significantly from that found in habitats that support plant and animal life. Topics include using new molecular techniques to discover more about bacteria; life at high temperatures, low temperatures, extreme pH levels and in a brine; and extremophiles in the evolution of life.

Madigan, Michael T.

352

Bacteria Allocation Using Monte Carlo  

NSDL National Science Digital Library

This applet, created by David Hill and Lila Roberts, uses the Monte Carlo technique to simulate a count of bacteria that are present as a result of a certain sampling process. This simulation could be modified to perform other experiments. This experiment is geared towards high school calculus students or probability courses for mathematics majors in college. Students must possess a basic understanding of probability concepts before performing this experiment. Overall, it is a nice activity for a mathematics classroom.

Hill, David R.

353

Bacteria turn a tiny gear  

SciTech Connect

Thousands of tiny Bacillus subtillis bacteria turn a single gear, just 380 microns across. (A human hair is about 100 microns across.) The method could be used to create micro-machines. Argonne National Laboratory scientist Igor Aronson pioneered this technique. Read more at the New York Times: http://ow.ly/ODfI or at Argonne: http://ow.ly/ODfa Video courtesy Igor Aronson.

None

2009-01-01

354

Lima Bean Bacteria DNA Extraction  

NSDL National Science Digital Library

This laboratory exercise is designed to show learners how DNA can easily be extracted from lima bean bacteria. This experiment requires the use of a centrifuge (not included in cost of materials). Use this experiment to supplement any unit on genetics and to demonstrate how scientists study DNA. Adult supervision is recommended. This resource guide includes tips and suggestions for instructors as well as other DNA extraction experiments and a chart for learners to answer questions.

Lana Hays

2009-01-01

355

F-LE Bacteria Populations  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A hospital is conducting a study to see how different environmental conditions influence the growth of streptococcus pneumonia, one of the bacteria whi...

2012-05-01

356

Regulating DNA Replication in Bacteria  

PubMed Central

The replication origin and the initiator protein DnaA are the main targets for regulation of chromosome replication in bacteria. The origin bears multiple DnaA binding sites, while DnaA contains ATP/ADP-binding and DNA-binding domains. When enough ATP-DnaA has accumulated in the cell, an active initiation complex can be formed at the origin resulting in strand opening and recruitment of the replicative helicase. In Escherichia coli, oriC activity is directly regulated by DNA methylation and specific oriC-binding proteins. DnaA activity is regulated by proteins that stimulate ATP-DnaA hydrolysis, yielding inactive ADP-DnaA in a replication-coupled negative-feedback manner, and by DnaA-binding DNA elements that control the subcellular localization of DnaA or stimulate the ADP-to-ATP exchange of the DnaA-bound nucleotide. Regulation of dnaA gene expression is also important for initiation. The principle of replication-coupled negative regulation of DnaA found in E. coli is conserved in eukaryotes as well as in bacteria. Regulations by oriC-binding proteins and dnaA gene expression are also conserved in bacteria. PMID:23471435

Skarstad, Kirsten; Katayama, Tsutomu

2013-01-01

357

Chemical signature of magnetotactic bacteria.  

PubMed

There are longstanding and ongoing controversies about the abiotic or biological origin of nanocrystals of magnetite. On Earth, magnetotactic bacteria perform biomineralization of intracellular magnetite nanoparticles under a controlled pathway. These bacteria are ubiquitous in modern natural environments. However, their identification in ancient geological material remains challenging. Together with physical and mineralogical properties, the chemical composition of magnetite was proposed as a promising tracer for bacterial magnetofossil identification, but this had never been explored quantitatively and systematically for many trace elements. Here, we determine the incorporation of 34 trace elements in magnetite in both cases of abiotic aqueous precipitation and of production by the magnetotactic bacterium Magnetospirillum magneticum strain AMB-1. We show that, in biomagnetite, most elements are at least 100 times less concentrated than in abiotic magnetite and we provide a quantitative pattern of this depletion. Furthermore, we propose a previously unidentified method based on strontium and calcium incorporation to identify magnetite produced by magnetotactic bacteria in the geological record. PMID:25624469

Amor, Matthieu; Busigny, Vincent; Durand-Dubief, Mickaël; Tharaud, Mickaël; Ona-Nguema, Georges; Gélabert, Alexandre; Alphandéry, Edouard; Menguy, Nicolas; Benedetti, Marc F; Chebbi, Imène; Guyot, François

2015-02-10

358

Current status and emerging role of glutathione in food grade lactic acid bacteria  

PubMed Central

Lactic acid bacteria (LAB) have taken centre stage in perspectives of modern fermented food industry and probiotic based therapeutics. These bacteria encounter various stress conditions during industrial processing or in the gastrointestinal environment. Such conditions are overcome by complex molecular assemblies capable of synthesizing and/or metabolizing molecules that play a specific role in stress adaptation. Thiols are important class of molecules which contribute towards stress management in cell. Glutathione, a low molecular weight thiol antioxidant distributed widely in eukaryotes and Gram negative organisms, is present sporadically in Gram positive bacteria. However, new insights on its occurrence and role in the latter group are coming to light. Some LAB and closely related Gram positive organisms are proposed to possess glutathione synthesis and/or utilization machinery. Also, supplementation of glutathione in food grade LAB is gaining attention for its role in stress protection and as a nutrient and sulfur source. Owing to the immense benefits of glutathione, its release by probiotic bacteria could also find important applications in health improvement. This review presents our current understanding about the status of glutathione and its role as an exogenously added molecule in food grade LAB and closely related organisms. PMID:22920585

2012-01-01

359

Protein signaling via type III secretion pathways in phytopathogenic bacteria  

E-print Network

109 Protein signaling via type III secretion pathways in phytopathogenic bacteria Mary Beth Mudgett secretion pathway has revealed new mechanisms by which phytopathogenic bacteria infect plants are continually exposed to a number of potentially pathogenic bacteria. Phytopathogenic bacteria, in general

Mudgettt, Mary Beth

360

A multifunctional probe with aggregation-induced emission characteristics for selective fluorescence imaging and photodynamic killing of bacteria over Mammalian cells.  

PubMed

A multifunctional probe aggregation-induced emission-Zinc(II)-dipicolylamine (AIE-ZnDPA) is developed for selective targeting, fluorescence imaging, and photodynamic killing of both Gram-positive and Gram-negative bacteria over mammalian cells. The probe has significant advantages in simple probe design, enhanced fluorescence upon bacteria binding, excellent photostability, and broad-spectrum antibacterial activity with almost no harm to mammalian cells. PMID:25530179

Gao, Meng; Hu, Qinglian; Feng, Guangxue; Tomczak, Nikodem; Liu, Rongrong; Xing, Bengang; Tang, Ben Zhong; Liu, Bin

2015-04-01

361

Characterization and evaluation of stress and heavy metal tolerance of some predominant Gram negative halotolerant bacteria from mangrove soils of Bhitarkanika, Orissa, India  

Microsoft Academic Search

In the present study both Gram positive and Gram negative bacteria were isolated using enrichment media from five different stations from mangroves soils of Bhitarkanika, Orissa, India. Among the bacterial populations studied, the Gram negative bacterial population was found to be more in all the stations. Out of several Gram negative bacterial isolates, six predominant and morphologically distinct isolates were

Rath B

362

Inactivation of Gram-positive biofilms by low-temperature plasma jet at atmospheric pressure  

NASA Astrophysics Data System (ADS)

This work is devoted to the evaluation of the efficiency of a new low-temperature plasma jet driven in ambient air by a dc-corona discharge to inactivate adherent cells and biofilms of Gram-positive bacteria. The selected microorganisms were lactic acid bacteria, a Weissella confusa strain which has the particularity to excrete a polysaccharide polymer (dextran) when sucrose is present. Both adherent cells and biofilms were treated with the low-temperature plasma jet for different exposure times. The antimicrobial efficiency of the plasma was tested against adherent cells and 48 h-old biofilms grown with or without sucrose. Bacterial survival was estimated using both colony-forming unit counts and fluorescence-based assays for bacterial cell viability. The experiments show the ability of the low-temperature plasma jet at atmospheric pressure to inactivate the bacteria. An increased resistance of bacteria embedded within biofilms is clearly observed. The resistance is also significantly higher with biofilm in the presence of sucrose, which indicates that dextran could play a protective role.

Marchal, F.; Robert, H.; Merbahi, N.; Fontagné-Faucher, C.; Yousfi, M.; Romain, C. E.; Eichwald, O.; Rondel, C.; Gabriel, B.

2012-08-01

363

Distribution and Diversity of Symbiotic Thermophiles, Symbiobacterium thermophilum and Related Bacteria, in Natural Environments  

PubMed Central

Symbiobacterium thermophilum is a tryptophanase-positive thermophile which shows normal growth only in coculture with its supporting bacteria. Analysis of the 16S rRNA gene (rDNA) indicated that the bacterium belongs to a novel phylogenetic branch at the outermost position of the gram-positive bacterial group without clustering to any other known genus. Here we describe the distribution and diversity of S. thermophilum and related bacteria in the environment. Thermostable tryptophanase activity and amplification of the specific 16S rDNA fragment were effectively employed to detect the presence of Symbiobacterium. Enrichment with kanamycin raised detection sensitivity. Mixed cultures of thermophiles containing Symbiobacterium species were frequently obtained from compost, soil, animal feces, and contents in the intestinal tracts, as well as feeds. Phylogenetic analysis and denaturing gradient gel electrophoresis of the specific 16S rDNA amplicons revealed a diversity of this group of bacteria in the environment. PMID:11525967

Ueda, Kenji; Ohno, Michiyo; Yamamoto, Kaori; Nara, Hanae; Mori, Yujiro; Shimada, Masafumi; Hayashi, Masahiko; Oida, Hanako; Terashima, Yuko; Nagata, Mitsuyo; Beppu, Teruhiko

2001-01-01

364

Genetics of acidophilic, heterotrophic bacteria  

SciTech Connect

The genetic characteristics of members of the genus Acidiphilium are poorly understood. As part of our study of the genetics of these bacteria, a search was made for an inducible, lysogenic bacteriophage. Such a bacteriophage has been discovered. Several properties of the phage have been investigated. The phage has a lambdoid morphology and is somewhat larger than lambda. A variety of factors which affect phage stability have been investigated. The bacteriophage infects several of the strains that have been tested. Study of this bacteriophage should greatly increase our understanding of genetic mechanisms in Acidiphilium. 23 refs., 3 figs., 1 tab.

Ward, T.E.; Bruhn, D.F.; Watkins, C.S.; Rowland, M.L.; Bulmer, D.K.; Winston, V.

1988-01-01

365

Bacteria and vampirism in cinema.  

PubMed

A vampire is a non-dead and non-alive chimerical creature, which, according to various folklores and popular superstitions, feeds on blood of the living to draw vital force. Vampires do not reproduce by copulation, but by bite. Vampirism is thus similar to a contagious disease contracted by intravascular inoculation with a suspected microbial origin. In several vampire films, two real bacteria were staged, better integrated than others in popular imagination: Yersinia pestis and Treponema pallidum. Bacillus vampiris was created for science-fiction. These films are attempts to better define humans through one of their greatest fears: infectious disease. PMID:23916557

Castel, O; Bourry, A; Thévenot, S; Burucoa, C

2013-09-01

366

Bacteria detection instrument and method  

NASA Technical Reports Server (NTRS)

A method and apparatus for screening a sample fluid for bacterial presence are disclosed wherein the fluid sample is mixed with culture media of sufficient quantity to permit bacterial growth in order to obtain a test solution. The concentration of oxygen dissolved in the test solution is then monitored using the potential difference between a reference electrode and a noble metal electrode which are in contact with the test solution. The change in oxygen concentration which occurs during a period of time as indicated by the electrode potential difference is compared with a detection criterion which exceeds the change which would occur absent bacteria.

Renner, W.; Fealey, R. D. (inventors)

1972-01-01

367

Digestion of Herring by Indigenous Bacteria in the Minke Whale Forestomach  

PubMed Central

Northeastern Atlantic minke whales (Balaenoptera acutorostrata) have a multichambered stomach system which includes a nonglandular forestomach resembling that of ruminants. Bacteria from the forestomachs of herring-eating whales were enumerated and isolated in an anaerobic rumen-like culture medium (M8W medium). The total viable population of anaerobic bacteria ranged from 73 × 107 to 145 × 108/ml of forestomach fluid (n = 4). Lactobacillus spp. (19.7%), Streptococcus spp. (35.9%), and Ruminococcus spp. (12.8%) were the most common of the bacterial strains (n = 117) isolated by use of M8W medium from the forestomach fluid population of two minke whales. Most of the isolates stained gram positive (93.2%), 62.4% were cocci, and all strains were strictly anaerobic. The population of lipolytic bacteria in one animal, enumerated by use of a selective lipid medium, constituted 89.7% of the viable population. The total viable population of anaerobic bacteria in freshly caught and homogenized herring (Clupea harengus) ranged from 56.7 to 95.0 cells per gram of homogenized prey (n = 3) when M8W medium was used. Pediococcus spp. (30.6%) and Aerococcus spp. (25.0%) were most common of the bacterial strains (n = 72) isolated from the homogenized herring. Most of the bacterial strains were gram positive (80.6%), and 70.8% were cocci. Unlike the forestomach bacterial population, as many as 61.1% of the strains from the herring were facultatively anaerobic. All bacterial strains isolated from the prey had phenotypic patterns different from those of strains isolated from the dominant bacterial population in the forestomach, indicating that the forestomach microbiota is indigenous. Scanning electron microscopic examinations revealed large numbers of bacteria, surrounded by a glycocalyx, attached to partly digested food particles in the forestomach. These data support the hypothesis that symbiotic microbial digestion occurs in the forestomach and that the bacteria are indigenous to minke whales. Images PMID:16349460

Olsen, Monica A.; Aagnes, Tove H.; Mathiesen, Svein D.

1994-01-01

368

Innate immune responses of human neonatal cells to bacteria from the normal gastrointestinal flora.  

PubMed

The hygiene hypothesis postulates that the prevalence of allergy has increased due to decreased microbial stimulation early in life, leading to delayed maturation of the immune system. The aim of this study was to examine the cytokine pattern produced from cord blood mononuclear cells relative to adult cells after stimulation with bacterial strains from the normal flora. Mononuclear cells from cord and adult blood samples were stimulated with the following bacteria: Bifidobacterium adolescentis, Enterococcus faecalis, Lactobacillus plantarum, Streptococcus mitis, Corynebacterium minutissimum, Clostridium perfringens, Bacteroides vulgatus, Escherichia coli, Pseudomonas aeruginosa, Veillonella parvula, and Neisseria sicca. The levels of interleukin 12 (IL-12), tumor necrosis factor alpha (TNF-alpha), IL-10, and IL-6 were measured by enzyme-linked immunosorbent assay. The TNF-alpha production was also analyzed after blocking CD14, Toll-like receptor 2 (TLR-2), and TLR-4 prior to stimulation with bacteria. The levels of IL-12 and TNF-alpha were similar in cord and adult cells. Gram-positive bacteria induced considerably higher levels of IL-12 and TNF-alpha than gram-negative bacteria in both cord and adult cells. The levels of IL-6 were significantly higher in newborns than in adults, whereas the levels of IL-10 were similar in newborns and adults. Gram-negative and gram-positive bacteria induced similar levels of IL-6 and IL-10 in cord cells. L. plantarum bound or signaled through CD14, TLR-2, and TLR-4, whereas E. coli acted mainly through CD14 and TLR-4. These results indicate that the innate immune response in newborns to commensal bacteria is strong and also suggest that different bacterial strains may have differential effects on the maturation of the immune system of infants. PMID:12438343

Karlsson, Helen; Hessle, Christina; Rudin, Anna

2002-12-01

369

Quantitative and Qualitative Analysis of Bacteria in Er(III) Solution by Thin-Film Magnetopheresis  

PubMed Central

Magnetic deposition, quantitation, and identification of bacteria reacting with the paramagnetic trivalent lanthanide ion, Er3+, was evaluated. The magnetic deposition method was dubbed thin-film magnetopheresis. The optimization of the magnetic deposition protocol was accomplished with Escherichia coli as a model organism in 150 mM NaCl and 5 mM ErCl3 solution. Three gram-positive bacteria, Staphylococcus epidermidis, Staphylococcus saprophyticus, and Enterococcus faecalis, and four gram-negative bacteria, E. coli, Pseudomonas aeruginosa, Proteus mirabilis, and Klebsiella pneumoniae, were subsequently investigated. Quantitative analysis consisted of the microscopic cell count and a scattered-light scanning of the magnetically deposited material aided by the computer data acquisition system. Qualitative analysis consisted of Gram stain differentiation and fluorescein isothiocyanate staining in combination with selected antisera against specific types of bacteria on the solid substrate. The magnetic deposition protocol allowed quantitative detection of E. coli down to the concentration of 105 CFU ml-1, significant in clinical diagnosis applications such as urinary tract infections. Er3+ did not interfere with the typical appearance of the Gram-stained bacteria nor with the antigen recognition by the antibody in the immunohistological evaluations. Indirect antiserum-fluorescein isothiocyanate labelling correctly revealed the presence of E. faecalis and P. aeruginosa in the magnetically deposited material obtained from the mixture of these two bacterial species. On average, the reaction of gram-positive organisms was significantly stronger to the magnetic field in the presence of Er3+ than the reaction of gram-negative organisms. The thin-film magnetophoresis offers promise as a rapid method for quantitative and qualitative analysis of bacteria in solutions such as urine or environmental water. Images PMID:16348916

Zborowski, Maciej; Tada, Yoko; Malchesky, Paul S.; Hall, Geraldine S.

1993-01-01

370

Characterizing the Catalytic Potential of Deinococcus, Arthrobacter and other Robust Bacteria in Contaminated Subsurface Environments of the Hanford Site  

SciTech Connect

Ionizing Radiation (IR) Resistance in Bacteria. Until recently, there have been no clear physiologic predictors of a cell's ability to recover from ionizing radiation (IR) and other DOE-relevant oxidative stress conditions. In general, the most resistant bacteria have been Gram-positive (e.g., Deinococcus, Arthrobacter, Lactobacillus & Enterococcus spp.) and the most sensitive have been Gram-negative (e.g., Pseudomonas, Shewanella & Neisseria spp.). However, there are several reported exceptions to this paradigm, the Gram-negative cyanobacterium Chroococcidiopsis is extremely resistant to IR, whereas the Gram-positive Micrococcus luteus is sensitive. We have identified biomolecular signatures for radiation sensitivity and resistance which are independent of phylogeny, where very high and very low intracellular Mn/Fe concentration ratios correlated with very high and very low resistances, respectively; and restricting Mn(II) in the famously resistant Deinococcus radiodurans sensitized this eubacterium to IR.

Daly, Michael J.

2006-05-01

371

Novel antimicrobial peptides that inhibit gram positive bacterial exotoxin synthesis.  

PubMed

Gram-positive bacteria, such as Staphylococcus aureus, cause serious human illnesses through combinations of surface virulence factors and secretion of exotoxins. Our prior studies using the protein synthesis inhibitor clindamycin and signal transduction inhibitors glycerol monolaurate and ?-globin and ?-globin chains of hemoglobin indicate that their abilities to inhibit exotoxin production by S. aureus are separable from abilities to inhibit growth of the organism. Additionally, our previous studies suggest that inhibition of exotoxin production, in absence of ability to kill S. aureus and normal flora lactobacilli, will prevent colonization by pathogenic S. aureus, while not interfering with lactobacilli colonization. These disparate activities may be important in development of novel anti-infective agents that do not alter normal flora. We initiated studies to explore the exotoxin-synthesis-inhibition activity of hemoglobin peptides further to develop potential agents to prevent S. aureus infections. We tested synthesized ?-globin chain peptides, synthetic variants of ?-globin chain peptides, and two human defensins for ability to inhibit exotoxin production without significantly inhibiting S. aureus growth. All of these peptides were weakly or not inhibitory to bacterial growth. However, the peptides were inhibitory to exotoxin production with increasing activity dependent on increasing numbers of positively-charged amino acids. Additionally, the peptides could be immobilized on agarose beads or have amino acid sequences scrambled and still retain exotoxin-synthesis-inhibition. The peptides are not toxic to human vaginal epithelial cells and do not inhibit growth of normal flora L. crispatus. These peptides may interfere with plasma membrane signal transduction in S. aureus due to their positive charges. PMID:24748386

Merriman, Joseph A; Nemeth, Kimberly A; Schlievert, Patrick M

2014-01-01

372

Novel co-enrichment method for isolation of magnetotactic bacteria.  

PubMed

A novel co-enrichment technique was designed for enrichment of magnetotactic bacteria from soil, water, and sediments. Delayed addition of iron uptake inducer and the iron source proved amenable to induce magnetosome synthesis by MTB followed by their separation from consortium using magnetic flux. We successfully enriched and isolated both North seeking as well as South seeking magnetotactic bacteria from Lonar Lake (Buldhana), Moti Lake (Jalna), Ghanewadi Lake (Jalna), Ganesh Lake (Miraj), Rankala Lake (Kolhapur), and industrial metal-contaminated glaying soils (Jalna) and a soil (Karad), (MS, India) exposed to high-voltage electric current. The hanging drop preparations and growth under magnetic stress on low-agar media allowed conformation of magnetotactic behavior of the isolates. Both Gram positive and Gram negative MTB were isolated with diverse morphologies. South seeking population was more predominant. The soil inhabitants showed little dwelling property which was more prominent in case of aquatic inhabitants. The use of in situ pH and salt concentrations during enrichment and isolation found suited. The simultaneous growth of whole consortium in the system ensured the in situ simulation of microenvironment needful for proper growth of fastidious MTB. PMID:25546328

Sorty, Ajay M; Shaikh, Nasir R

2015-04-01

373

Novel methylotrophic bacteria isolated from the River Thames (London, UK).  

PubMed

Enrichment and elective culture for methylotrophs from sediment of the River Thames in central London yielded a diversity of pure cultures representing several genera of Gram-negative and Gram-positive bacteria, which were mainly of organisms not generally regarded as typically methylotrophic. Substrates leading to successful isolations included methanol, monomethylamine, dimethylamine, trimethylamine, methanesulfonate and dimethylsulfone. Several isolates were studied in detail and shown by their biochemical and morphological properties and 16S rRNA gene sequencing to be Sphingomonas melonis strain ET35, Mycobacterium fluoranthenivorans strain DSQ3, Rhodococcus erythropolis strain DSQ4, Brevibacterium casei strain MSQ5, Klebsiella oxytoca strains MMA/F and MMA/1, Pseudomonas mendocina strain TSQ4, and Flavobacterium sp. strains MSA/1 and MMA/2. The results show that facultative methylotrophy is present across a wide range of Bacteria, suggesting that turnover of diverse C(1)-compounds is of much greater microbiological and environmental significance than is generally thought. The origins of the genes encoding the enzymes of methylotrophy in diverse heterotrophs need further study, and could further our understanding of the phylogeny and antiquity of methylotrophic systems. PMID:18681896

Boden, Rich; Thomas, Elizabeth; Savani, Parita; Kelly, Donovan P; Wood, Ann P

2008-12-01

374

Dancing to Another Tune—Adhesive Moonlighting Proteins in Bacteria  

PubMed Central

Biological moonlighting refers to proteins which express more than one function. Moonlighting proteins occur in pathogenic and commensal as well as in Gram-positive and Gram-negative bacteria. The canonical functions of moonlighting proteins are in essential cellular processes, i.e., glycolysis, protein synthesis, chaperone activity, and nucleic acid stability, and their moonlighting functions include binding to host epithelial and phagocytic cells, subepithelia, cytoskeleton as well as to mucins and circulating proteins of the immune and hemostatic systems. Sequences of the moonlighting proteins do not contain known motifs for surface export or anchoring, and it has remained open whether bacterial moonlighting proteins are actively secreted to the cell wall or whether they are released from traumatized cells and then rebind onto the bacteria. In lactobacilli, ionic interactions with lipoteichoic acids and with cell division sites are important for surface localization of the proteins. Moonlighting proteins represent an abundant class of bacterial adhesins that are part of bacterial interactions with the environment and in responses to environmental changes. Multifunctionality in bacterial surface proteins appears common: the canonical adhesion proteins fimbriae express also nonadhesive functions, whereas the mobility organelles flagella as well as surface proteases express adhesive functions. PMID:24833341

Kainulainen, Veera; Korhonen, Timo K.

2014-01-01

375

Genetic manipulation of acidophilic bacteria  

SciTech Connect

Thiobacillus ferrooxidans is important in leaching of metals from mineral ores and in the removal of pyritic sulfur from coal. It is also intimately involved in production of acid mine drainage. Other acidophilic bacteria, including members of the genus Acidiphilium, are usually present in the same environments as T. ferrooxidans, and there is evidence to suggest that these acidophilic heterotrophs may increase the rate of T. ferrooxidans' attack on inorganic sulfides. Our laboratory is studying the genetic characteristics of these acidophilic bacteria and developing techniques for introducing desirable genes into them. Several endogenous plasmids from Acidiphilium strains have been cloned into E. coli vectors. Some of the resulting plasmids are able to confer antibiotic resistance to Acidiphilium after transformation by electroporation. In addition, a broad-host range plasmid conferring resistance to tetracycline has been introduced into Acidiphilium strains by electroporation. This same plasmid, has also been transferred to Acidiphilium from E. coli directly by conjugation. A temperate bacteriophage which infects a number of Acidiphilium isolates has been discovered and partially characterized. It has a lambdoid morphology and a genome of approximately 97 kb, comprised of double-stranded DNA which is probably modified. 16 refs., 2 figs., 4 tabs.

Ward, T.E.; Rowland, M.L.; Glenn, A.W.; Watkins, C.S.; Bruhn, D.F.; Bulmer, D.; Roberto, F.F.

1989-01-01

376

DNA fingerprinting of oral bacteria.  

PubMed

This elective study was conducted at the Dental School, University of Wales College of Medicine and at the University of Wales College of Cardiff School of Pure and Applied Biology. The student's interest in oral microbiology and desire to contribute to the work being performed in the field of oral microbiology, led him to concentrate his study on developing a DNA fingerprinting method to evaluate the putative new species of the genus Capnocytophaga. The genus Capnocytophaga, which contains Gram-negative, capnophilic fusiform-shaped bacteria, has been implicated in juvenile periodontitis and prepubertal gingivitis. However, the genus is also part of the normal oral flora. The student believed that there was an implication of the existence of both pathogenic and non-pathogenic strains of Capnocytophaga and developed a method of DNA fingerprinting to distinguish Capnocytophaga strains from clusters identified by Khwaja et al. The student felt that the study allowed insight into the tremendous potential of molecular techniques for furthering the understanding of dental disease and confirmed his ambition to pursue a career in academic oral microbiology. This area of study allows new associations to be made between specific bacteria and diseases, aiding the possibility of rapid and early diagnosis. PMID:1739503

Lancashire, P

1992-01-25

377

DMTB: the magnetotactic bacteria database  

NASA Astrophysics Data System (ADS)

Magnetotactic bacteria (MTB) are of interest in biogeomagnetism, rock magnetism, microbiology, biomineralization, and advanced magnetic materials because of their ability to synthesize highly ordered intracellular nano-sized magnetic minerals, magnetite or greigite. Great strides for MTB studies have been made in the past few decades. More than 600 articles concerning MTB have been published. These rapidly growing data are stimulating cross disciplinary studies in such field as biogeomagnetism. We have compiled the first online database for MTB, i.e., Database of Magnestotactic Bacteria (DMTB, http://database.biomnsl.com). It contains useful information of 16S rRNA gene sequences, oligonucleotides, and magnetic properties of MTB, and corresponding ecological metadata of sampling sites. The 16S rRNA gene sequences are collected from the GenBank database, while all other data are collected from the scientific literature. Rock magnetic properties for both uncultivated and cultivated MTB species are also included. In the DMTB database, data are accessible through four main interfaces: Site Sort, Phylo Sort, Oligonucleotides, and Magnetic Properties. References in each entry serve as links to specific pages within public databases. The online comprehensive DMTB will provide a very useful data resource for researchers from various disciplines, e.g., microbiology, rock magnetism and paleomagnetism, biogeomagnetism, magnetic material sciences and others.

Pan, Y.; Lin, W.

2012-12-01

378

Money and transmission of bacteria.  

PubMed

Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria to people who come in contact with the banknotes. The survival rate was highest for the Romanian Leu yielding all three microorganisms used after both three and six hours of drying. Furthermore, the Leu was the only banknote to yield VRE after one day of drying. Other currencies either enabled the survival of Extended-Spectrum Beta-Lactamases (ESBL) and VRE (e.g. Euro), but not of MRSA, or the other way round (e.g. US Dollar). While a variety of factors such as community hygiene levels, people's behaviour, and antimicrobial resistance rates at community level obviously have influence on the transmission of resistant microorganisms, the type of banknote-paper may be an additional variable to consider. PMID:23985137

Gedik, Habip; Voss, Timothy A; Voss, Andreas

2013-01-01

379

Collective Motion of Spherical Bacteria  

PubMed Central

A large variety of motile bacterial species exhibit collective motions while inhabiting liquids or colonizing surfaces. These collective motions are often characterized by coherent dynamic clusters, where hundreds of cells move in correlated whirls and jets. Previously, all species that were known to form such motion had a rod-shaped structure, which enhances the order through steric and hydrodynamic interactions. Here we show that the spherical motile bacteria Serratia marcescens exhibit robust collective dynamics and correlated coherent motion while grown in suspensions. As cells migrate to the upper surface of a drop, they form a monolayer, and move collectively in whirls and jets. At all concentrations, the distribution of the bacterial speed was approximately Rayleigh with an average that depends on concentration in a non-monotonic way. Other dynamical parameters such as vorticity and correlation functions are also analyzed and compared to rod-shaped bacteria from the same strain. Our results demonstrate that self-propelled spherical objects do form complex ordered collective motion. This opens a door for a new perspective on the role of cell aspect ratio and alignment of cells with regards to collective motion in nature. PMID:24376741

Rabani, Amit; Ariel, Gil; Be'er, Avraham

2013-01-01

380

Money and transmission of bacteria  

PubMed Central

Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria to people who come in contact with the banknotes. The survival rate was highest for the Romanian Leu yielding all three microorganisms used after both three and six hours of drying. Furthermore, the Leu was the only banknote to yield VRE after one day of drying. Other currencies either enabled the survival of Extended-Spectrum Beta-Lactamases (ESBL) and VRE (e.g. Euro), but not of MRSA, or the other way round (e.g. US Dollar). While a variety of factors such as community hygiene levels, people’s behaviour, and antimicrobial resistance rates at community level obviously have influence on the transmission of resistant microorganisms, the type of banknote-paper may be an additional variable to consider. PMID:23985137

2013-01-01

381

Taurolidine Antiadhesive Properties on Interaction with E. coli; Its Transformation in Biological Environment and Interaction with Bacteria Cell Wall  

Microsoft Academic Search

The taurine amino-acid derivative, taurolidine, bis-(1,1-dioxoperhydro-1,2,4-thiabiazinyl–4)methane, shows broad antibacterial action against gram-positive and gram-negative bacteria, mycobacteria and some clinically relevant fungi. It inhibits, in vitro, the adherence of Escherichia coli and Staphylococcus aureus to human epithelial and fibroblast cells. Taurolidine is unstable in aqueous solution and breaks down into derivatives which are thought to be responsible for the biological activity.

Francesco Caruso; James W. Darnowski; Cristian Opazo; Alexander Goldberg; Nina Kishore; Elin S. Agoston; Miriam Rossi; Jörg Hoheisel

2010-01-01

382

Phylogenetic Diversity of Lactic Acid Bacteria Associated with Paddy Rice Silage as Determined by 16S Ribosomal DNA Analysis  

Microsoft Academic Search

A total of 161 low-GC-content gram-positive bacteria isolated from whole-crop paddy rice silage were classified and subjected to phenotypic and genetic analyses. Based on morphological and biochemical char- acters, these presumptive lactic acid bacterium (LAB) isolates were divided into 10 groups that included members of the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and Weissella. Analysis of the 16S ribosomal DNA

Saïd Ennahar; Yimin Cai; Yasuhito Fujita

2003-01-01

383

Occurrence of tetracycline resistance genes tet(M) and tet(S) in bacteria from marine aquaculture sites  

Microsoft Academic Search

Occurrence of tetracycline resistance genes encoding ribosomal protection proteins was examined in 151 tetracycline-resistant bacterial isolates from fish and seawater at coastal aquaculture sites in Japan and Korea. The tet(M) gene was detected in 34 Japanese and Korean isolates, which included Vibrio sp., Lactococcus garvieae, Photobacterium damsela subsp. piscicida, and unidentified Gram-positive bacteria. The majority of these bacterial isolates displayed

Seok-Ryel Kim; Lisa Nonaka; Satoru Suzuki

2004-01-01

384

Analysis of the composition and characteristics of culturable endophytic bacteria within subnival plants of the Tianshan Mountains, northwestern China.  

PubMed

This study first described the composition and characteristics of culturable endophytic bacteria isolated from wild alpine-subnival plant species growing under extreme environmental conditions (i.e., on the border of a glacier with frequently fluctuating and freezing temperatures, strong wind, and high ultraviolet radiation). Using a cultivation-dependent approach and 16S rRNA gene amplification techniques, 93 bacterial isolates showing different phenotypic properties were obtained from 20 different subnival plant species, of which gram-positive bacteria (61.5%), psychrotolerant bacteria (67.3%), and pigmented isolates (70.9%) accounted for a large proportion. All these characteristics of endophytes were closely related to the survival environment of their host plants and were in good agreement with microbes occurring in other cold environments. Phylogenetic analysis indicated that the endophytic isolates consisted of five phylogenetic groups comprising ?-proteobacteria, ?-proteobacteria, the high G+C content gram-positive bacteria, the low G+C content gram-positive bacteria, and Flavobacterium-Bacteroides-Cytophaga. The largest generic diversity was found in the HGC group, while Clavibacter, Agreia, Rhodococcus, Sphingomonas, and Pseudomonas were the most prevalent genera. Of all isolates, 46.4% showed a high sequence similarity (98-100%) to strains discovered from other cold environments such as glaciers, tundra, and polar seas. Furthermore, 36.4% of the isolates produced Indole-3-acetic acid and 76.3% were able to solubilize mineral phosphate, which revealed that endophytic bacteria with multiple physiological functions were abundant and widespread in subnival plants. These results are essential for understanding the ecological roles of endophytes and as a foundation for further studying the interactions with plants and environment. PMID:21061126

Sheng, Hong Mei; Gao, Hong Shan; Xue, Lin Gui; Ding, Shuo; Song, Chun Li; Feng, Hu Yuan; An, Li Zhe

2011-03-01

385

5, 317359, 2008 Bacteria dynamics in  

E-print Network

BGD 5, 317­359, 2008 Bacteria dynamics in mesocosms with increased pCO2 M. Allgaier et al. Title of heterotrophic bacteria to phytoplankton bloom development at different pCO2 levels: a mesocosm study M. Allgaier@igb-berlin.de) 317 #12;BGD 5, 317­359, 2008 Bacteria dynamics in mesocosms with increased pCO2 M. Allgaier et al

Paris-Sud XI, Université de

386

Managing Bacteria Pollution in Texas Waters  

E-print Network

Story by Kathy Wythe tx H2O | pg. 2 BACTERIA MANAGING tx H2O | pg. 3 IN TEXAS WATERS POLLUTION Managing Bacteria Pollution in Texas Waters tx H2O | pg. 4 W ith 310 water bodies in Texas failing to meetwater quality standards because... of bacteria,managing bacteria pollution is commanding the attention of water agencies, researchers and stake- holders across Texas. These water bodies are listed in the 2006 Texas Water Quality Inventory and 303(d) List for failing to meet the standards...

Wythe, Kathy

2007-01-01

387

Spectroscopic diagnostics for bacteria in biologic sample  

DOEpatents

A method to analyze and diagnose specific bacteria in a biologic sample using spectroscopy is disclosed. The method includes obtaining the spectra of a biologic sample of a non-infected patient for use as a reference, subtracting the reference from the spectra of an infected sample, and comparing the fingerprint regions of the resulting differential spectrum with reference spectra of bacteria in saline. Using this diagnostic technique, specific bacteria can be identified sooner and without culturing, bacteria-specific antibiotics can be prescribed sooner, resulting in decreased likelihood of antibiotic resistance and an overall reduction of medical costs.

El-Sayed, Mostafa A. (Atlanta, GA); El-Sayed, Ivan H. (Somerville, MA)

2002-01-01

388

Survival of soil bacteria during prolonged desiccation.  

NASA Technical Reports Server (NTRS)

A determination was made of the kinds and numbers of bacteria surviving when two soils were maintained in the laboratory under dry conditions for more than half a year. Certain non-spore-forming bacteria were found to survive in the dry condition for long periods. A higher percentage of drought-tolerant than drought-sensitive bacteria was able to grow at low water activities. When they were grown in media with high salt concentrations, bacteria generally became more tolerant of prolonged drought and they persisted longer. The percent of cells in a bacterial population that remained viable when exposed to drought stress varied with the stage of growth.

Chen, M.; Alexander, M.

1973-01-01

389

Generating and Exploiting Polarity in Bacteria  

NSDL National Science Digital Library

Bacteria are often highly polarized, exhibiting specialized structures at or near the ends of the cell. Among such structures are actin-organizing centers, which mediate the movement of certain pathogenic bacteria within the cytoplasm of an animal host cell; organized arrays of membrane receptors, which govern chemosensory behavior in swimming bacteria; and asymmetrically positioned septa, which generate specialized progeny in differentiating bacteria. This polarization is orchestrated by complex and dynamic changes in the subcellular localization of signal transduction and cytoskeleton proteins as well as of specific regions of the chromosome. Recent work has provided information on how dynamic subcellular localization occurs and how it is exploited by the bacterial cell.

Lucy Shapiro (Stanford University School of Medicine; Department of Developmental Biology)

2002-12-06

390

Antimicrobial activities of novel cultivable bacteria isolated from marine sponge Tedania anhelans  

NASA Astrophysics Data System (ADS)

Marine sponge Tedania anhelans distributes throughout the intertidal zone of Fujian, southeastern China, and is a potential source of natural bioactive products. The sponge harbors a large number of bacterial groups that have been identified using various techniques, including fluorescent in situ hybridization (FISH). Fractionation of dissociated sponge allowed isolation of 25 bacterial species. Based on 16S rRNA gene sequencing, phylogenetic analysis attributed most of these eubacteria to ?- Proteobacteria, ?- Proteobacteria, Cytophaga / Flavobacterium / Bacteroidetes (CFB group), and the family Bacillaceae of Gram-positive bacteria. In sequence similarity, five putatively novel species were identified with less than 98% similarity to other strains in the NCBI database. Tests for antimicrobial activities were performed against Gram-positive bacteria, Gram-negative bacteria, fungi, antitumor indicators Escherichia coli 343/591 (with DNA repair deficiency), regular E. coli 343/636 (with different DNA repair capacity), and 10 bacterial isolates exhibited inhibitory bioactivities. Among these strains, three isolates were detected involving function gene NRPS-A domains, which were most closely related to the amino acid sequences of linear gramicidin synthetase and pyoverdine synthetase. These results contribute to our knowledge of the microbes associated with marine sponges and further reveal novel bacterial resources for the screening of bioactive marine natural products.

Zeng, Zhen; Zhao, Jing; Ke, Caihuan; Wang, Dexiang

2013-05-01

391

Synergistic Antimicrobial Activity of Camellia sinensis and Juglans regia against Multidrug-Resistant Bacteria.  

PubMed

Synergistic combinations of antimicrobial agents with different mechanisms of action have been introduced as more successful strategies to combat infections involving multidrug resistant (MDR) bacteria. In this study, we investigated synergistic antimicrobial activity of Camellia sinensis and Juglans regia which are commonly used plants with different antimicrobial agents. Antimicrobial susceptibility of 350 Gram-positive and Gram-negative strains belonging to 10 different bacterial species, was tested against Camellia sinensis and Juglans regia extracts. Minimum inhibitory concentrations (MICs) were determined by agar dilution and microbroth dilution assays. Plant extracts were tested for synergistic antimicrobial activity with different antimicrobial agents by checkerboard titration, Etest/agar incorporation assays, and time kill kinetics. Extract treated and untreated bacteria were subjected to transmission electron microscopy to see the effect on bacterial cell morphology. Camellia sinensis extract showed higher antibacterial activity against MDR S. Typhi, alone and in combination with nalidixic acid, than to susceptible isolates." We further explore anti-staphylococcal activity of Juglans regia that lead to the changes in bacterial cell morphology indicating the cell wall of Gram-positive bacteria as possible target of action. The synergistic combination of Juglans regia and oxacillin reverted oxacillin resistance of methicillin resistant Staphylococcus aureus (MRSA) strains in vitro. This study provides novel information about antimicrobial and synergistic activity of Camellia sinensis and Juglans regia against MDR pathogens. PMID:25719410

Farooqui, Amber; Khan, Adnan; Borghetto, Ilaria; Kazmi, Shahana U; Rubino, Salvatore; Paglietti, Bianca

2015-01-01

392

Time-resolved and steady-state fluorescence spectroscopy from bacteria subjected to bactericidal agents  

NASA Astrophysics Data System (ADS)

The time-resolved and steady-state changes in fluorescence were investigated from one spore-forming (Bacillus subtilis) and four non-spore forming (Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Pseudomonas aeruginosa) bacteria subjected to different bactericidal agents. The bactericidal agents were sodium hypochlorite (bleach) hydrogen peroxide, formaldehyde, and UV light exposure. Application of sodium hypochlorite resulted in an almost total lose of fluorescence signal and large decrease in the optical density of the bacterial suspension. Addition of hydrogen peroxide resulted in a 35% decrease in emission intensity fom the Sa and an 85-95% decrease for the other bacteria. Ultraviolet light exposure resulted in a 5-35% decrease in the emission intensity of the tryptophan band. The addition of formaldehyde to the bacteria did not result in significant changes in the steady-state emission intensity, but did shift the tryptophan emission peak position to shorter wavelengths by 3 to 5 nm. Time-resolved fluorescence measurements showed that the fluorescence lifetime of tryptophan in the bacteria could not be described by a single exponential decay, and was similar to that of tryptophan in neutral aqueous solution. Upon addition of formaldehyde to the Gram positive bacteria (Bs and Sa) the strength of the short lifetime component increased dramatically, while for the Gram negative bacteria, a smaller increase was observed. These fluorescence changes reflect the different mechanisms of the bactericidal agents and may provide a useful tool to monitor the effectiveness of disinfectants.

Katz, Alvin; Alimova, Alexandra; Siddique, Masood; Savage, Howard E.; Shah, Mahendra; Rosen, Richard; Alfano, Robert

2004-03-01

393

Screening of plant extracts for antimicrobial activity against bacteria and yeasts with dermatological relevance.  

PubMed

There is cumulative resistance against antibiotics of many bacteria. Therefore, the development of new antiseptics and antimicrobial agents for the treatment of skin infections is of increasing interest. We have screened six plant extracts and isolated compounds for antimicrobial effects on bacteria and yeasts with dermatological relevance. The following plant extracts have been tested: Gentiana lutea, Harpagophytum procumbens, Boswellia serrata (dry extracts), Usnea barbata, Rosmarinus officinalis and Salvia officinalis (supercritical carbon dioxide [CO2] extracts). Additionally, the following characteristic plant substances were tested: usnic acid, carnosol, carnosic acid, ursolic acid, oleanolic acid, harpagoside, boswellic acid and gentiopicroside. The extracts and compounds were tested against 29 aerobic and anaerobic bacteria and yeasts in the agar dilution test. U. barbata-extract and usnic acid were the most active compounds, especially in anaerobic bacteria. Usnea CO2-extract effectively inhibited the growth of several Gram-positive bacteria like Staphylococcus aureus (including methicillin-resistant strains - MRSA), Propionibacterium acnes and Corynebacterium species. Growth of the dimorphic yeast Malassezia furfur was also inhibited by Usnea-extract. Besides the Usnea-extract, Rosmarinus-, Salvia-, Boswellia- and Harpagophytum-extracts proved to be effective against a panel of bacteria. It is concluded that due to their antimicrobial effects some of the plant extracts may be used for the topical treatment of skin disorders like acne vulgaris and seborrhoic eczema. PMID:17291738

Weckesser, S; Engel, K; Simon-Haarhaus, B; Wittmer, A; Pelz, K; Schempp, C M

2007-08-01

394

Essential genes from Arctic bacteria used to construct stable, temperature-sensitive bacterial vaccines.  

PubMed

All bacteria share a set of evolutionarily conserved essential genes that encode products that are required for viability. The great diversity of environments that bacteria inhabit, including environments at extreme temperatures, place adaptive pressure on essential genes. We sought to use this evolutionary diversity of essential genes to engineer bacterial pathogens to be stably temperature-sensitive, and thus useful as live vaccines. We isolated essential genes from bacteria found in the Arctic and substituted them for their counterparts into pathogens of mammals. We found that substitution of nine different essential genes from psychrophilic (cold-loving) bacteria into mammalian pathogenic bacteria resulted in strains that died below their normal-temperature growth limits. Substitution of three different psychrophilic gene orthologs of ligA, which encode NAD-dependent DNA ligase, resulted in bacterial strains that died at 33, 35, and 37 degrees C. One ligA gene was shown to render Francisella tularensis, Salmonella enterica, and Mycobacterium smegmatis temperature-sensitive, demonstrating that this gene functions in both Gram-negative and Gram-positive lineage bacteria. Three temperature-sensitive F. tularensis strains were shown to induce protective immunity after vaccination at a cool body site. About half of the genes that could be tested were unable to mutate to temperature-resistant forms at detectable levels. These results show that psychrophilic essential genes can be used to create a unique class of bacterial temperature-sensitive vaccines for important human pathogens, such as S. enterica and Mycobacterium tuberculosis. PMID:20624965

Duplantis, Barry N; Osusky, Milan; Schmerk, Crystal L; Ross, Darrell R; Bosio, Catharine M; Nano, Francis E

2010-07-27

395

Essential genes from Arctic bacteria used to construct stable, temperature-sensitive bacterial vaccines  

PubMed Central

All bacteria share a set of evolutionarily conserved essential genes that encode products that are required for viability. The great diversity of environments that bacteria inhabit, including environments at extreme temperatures, place adaptive pressure on essential genes. We sought to use this evolutionary diversity of essential genes to engineer bacterial pathogens to be stably temperature-sensitive, and thus useful as live vaccines. We isolated essential genes from bacteria found in the Arctic and substituted them for their counterparts into pathogens of mammals. We found that substitution of nine different essential genes from psychrophilic (cold-loving) bacteria into mammalian pathogenic bacteria resulted in strains that died below their normal-temperature growth limits. Substitution of three different psychrophilic gene orthologs of ligA, which encode NAD-dependent DNA ligase, resulted in bacterial strains that died at 33, 35, and 37 °C. One ligA gene was shown to render Francisella tularensis, Salmonella enterica, and Mycobacterium smegmatis temperature-sensitive, demonstrating that this gene functions in both Gram-negative and Gram-positive lineage bacteria. Three temperature-sensitive F. tularensis strains were shown to induce protective immunity after vaccination at a cool body site. About half of the genes that could be tested were unable to mutate to temperature-resistant forms at detectable levels. These results show that psychrophilic essential genes can be used to create a unique class of bacterial temperature-sensitive vaccines for important human pathogens, such as S. enterica and Mycobacterium tuberculosis. PMID:20624965

Duplantis, Barry N.; Osusky, Milan; Schmerk, Crystal L.; Ross, Darrell R.; Bosio, Catharine M.; Nano, Francis E.

2010-01-01

396

Current Perspectives on Viable but Non-Culturable (VBNC) Pathogenic Bacteria  

PubMed Central

Under stress conditions, many species of bacteria enter into starvation mode of metabolism or a physiologically viable but non-culturable (VBNC) state. Several human pathogenic bacteria have been reported to enter into the VBNC state under these conditions. The pathogenic VBNC bacteria cannot be grown using conventional culture media, although they continue to retain their viability and express their virulence. Though there have been debates on the VBNC concept in the past, several molecular studies have shown that not only can the VBNC state be induced under in vitro conditions but also that resuscitation from this state is possible under appropriate conditions. The most notable advance in resuscitating VBNC bacteria is the discovery of resuscitation-promoting factor (Rpf), which is a bacterial cytokines found in both Gram-positive and Gram-negative organisms. VBNC state is a survival strategy adopted by the bacteria, which has important implication in several fields, including environmental monitoring, food technology, and infectious disease management; and hence it is important to investigate the association of bacterial pathogens under VBNC state and the water/foodborne outbreaks. In this review, we describe various aspects of VBNC bacteria, which include their proteomic and genetic profiles under the VBNC state, conditions of resuscitation, methods of detection, antibiotic resistance, and observations on Rpf. PMID:25133139

Ramamurthy, Thandavarayan; Ghosh, Amit; Pazhani, Gururaja P.; Shinoda, Sumio

2014-01-01

397

Multidrug-Resistance and Toxic Metal Tolerance of Medically Important Bacteria Isolated from an Aquaculture System  

PubMed Central

The use of antimicrobials and toxic metals should be considered carefully in aquaculture and surrounding environments. We aimed to evaluate medically relevant bacteria in an aquaculture system and their susceptibility to antimicrobials and toxic metals. Selective cultures for enterobacteria (ENT), non-fermenting Gram-negative rods (NFR) and Gram-positive cocci (GPC) were obtained from water samples collected in two different year seasons. The isolated bacteria were biochemically identified and antimicrobial and toxic metal susceptibility patterns were determined. Overall, 407 representative strains were recovered. In general, bacteria isolated from fish ponds showed higher multiple antibiotic resistance indices when compared to those isolated from a water-fed canal. Resistance to penicillin and azithromycin was observed more frequently in the GPC group, whereas resistance to ampicillin and ampicillin/sulbactam or gentamicin was observed more frequently in the ENT and NFR groups, respectively. All the isolated bacteria were tolerant to nickel, zinc, chromium and copper at high levels (?1,024 ?g mL?1), whereas tolerance to cadmium and mercury varied among the isolated bacteria (2–1,024 ?g mL?1). Multidrug-resistant bacteria were more frequent and diverse in fish ponds than in the water-fed canal. A positive correlation was observed between antimicrobial resistance and metal tolerance. The data point out the need for water treatment associated with the aquaculture system. PMID:22972388

Resende, Juliana Alves; Silva, Vânia L.; Fontes, Cláudia Oliveira; Souza-Filho, Job Alves; de Oliveira, Tamara Lopes Rocha; Coelho, Cíntia Marques; César, Dionéia Evangelista; Diniz, Cláudio Galuppo

2012-01-01

398

Cultivable bacteria from ancient algal mats from the McMurdo Dry Valleys, Antarctica.  

PubMed

The McMurdo Dry Valleys in Antarctica are a favorable location for preservation of dormant microbes due to their persistent cold and dry climate. In this study, we examined cultivable bacteria in a series of algal mat samples ranging from 8 to 26539 years old. Cultivable bacteria were found in all samples except one (12303 years old), but abundance and diversity of cultivable bacteria decreased with increasing sample age. Only members of the Actinobacteria, Bacteroidetes, and Firmicutes were found in the ancient samples, whereas bacteria in the 8-year-old sample also included Cyanobacteria, Proteobacteria, and Deinococcus-Thermus. Isolates of the Gram-positive spore-forming bacterium Sporosarcina were found in 5 of 8 samples. The growth of these isolates at different temperatures was related to the phylogenetic distance among genotypes measured by BOX-PCR. These findings suggest that adaptation to growth at different temperatures had occurred among Sporosarcina genotypes in the Dry Valleys, causing the existence of physiologically distinct but closely related genotypes. Additionally, fully psychrophilic isolates (that grew at 15°C, but not 25°C) were found in ancient samples, but not in the modern sample. The preservation of viable bacteria in the Dry Valleys could potentially represent a legacy of bacteria that impacts on current microbial communities of this environment. PMID:22065250

Antibus, Doug E; Leff, Laura G; Hall, Brenda L; Baeseman, Jenny L; Blackwood, Christopher B

2012-01-01

399

Enzymatic modification of regenerated cellulosic fabrics to improve bacteria sorption properties.  

PubMed

This research investigates the effect of enzymatic treatment of two different regenerated cellulosic fibers (Lyocell and viscose) on their ability of bacteria sorption from an aqueous suspension. The sorption of Escherichia coli (E. coli, Gram negative) and Staphylococcus aureus (S. aureus, Gram positive) cells by treated Lyocell and viscose fabrics were determined by measuring the optical density (OD) of the remaining bacteria suspension after removal of the fabric samples using spectrometry. Fourier transform infrared spectroscopy and scanning electron microscopy (SEM) were utilized to investigate structural and morphological changes of the enzyme treated samples. The result showed that the moisture content and crystallinity of both viscose and Lyocell samples increased after enzymatic treatment. Comparing the results of OD measurements indicated that enzymatic treatment of cellulosic samples significantly increased the bacteria absorption properties compared to those untreated samples. However, treated samples showed different ranges of sorption ability with different kinds of bacteria. The maximum bacteria sorption of 38% and 37% of E. coli bacteria from an aqueous suspension was found for the treated viscose and Lyocell samples compared with only 20% and 10% of the untreated viscose and Lyocell samples, respectively. It was also found that S. aureus sorption of cellulose-treated viscose and Lyocell fabrics from a bacterial suspension could significantly improve up to 33% compared with only 5% of untreated samples. Furthermore, SEM micrographs confirmed that bacterial sorption of the cellulose-treated samples were effectively improved in terms of their uniform sorption on the fibers surface. PMID:23184868

Akbari, M; Dadadashian, F; Kordestani, S S; Xue, M; Jackson, C J

2013-06-01

400

Antimicrobial potential of immobilized Lactococcus lactis subsp. lactis ATCC 11454 against selected bacteria.  

PubMed

Immobilization of living cells of lactic acid bacteria could be an alternative or complementary method of immobilizing organic acids and bacteriocins and inhibit undesirable bacteria in foods. This study evaluated the inhibition potential of immobilized Lactococcus lactis subsp. lactis ATCC 11454 on selected bacteria by a modified method of the agar spot test. L. lactis was immobilized in calcium alginate (1 to 2%)-whey protein concentrate (0 and 1%) beads. The antimicrobial potential of immobilized L. lactis was evaluated in microbiological media against pathogenic bacteria (Escherichia coli, Salmonella, and Staphylococcus aureus) or Pseudomonas putida, a natural meat contaminant, and against seven gram-positive bacteria used as indicator strains. Results obtained in this study indicated that immobilized L. lactis inhibited the growth of S. aureus, Enterococcus faecalis, Enterococcus faecium, Lactobacillus curvatus, Lactobacillus sakei, Kocuria varians, and Pediococcus acidilactici. Only 4 h of incubation at 35 degrees C resulted in a clear inhibition zone around the beads that increased with time. With the addition of 10 mM of a chelating agent (EDTA) to the media, results showed growth inhibition of E. coli; however, P. putida and Salmonella Typhi were unaffected by this treatment. These results indicate that immobilized lactic acid bacteria strains can be successfully used to produce nisin and inhibit bacterial growth in semisolid synthetic media. PMID:15222547

Millette, M; Smoragiewicz, W; Lacroix, M

2004-06-01

401

Common Virulence Factors and Tissue Targets of Entomopathogenic Bacteria for Biological Control of Lepidopteran Pests  

PubMed Central

This review focuses on common insecticidal virulence factors from entomopathogenic bacteria with special emphasis on two insect pathogenic bacteria Photorhabdus (Proteobacteria: Enterobacteriaceae) and Bacillus (Firmicutes: Bacillaceae). Insect pathogenic bacteria of diverse taxonomic groups and phylogenetic origin have been shown to have striking similarities in the virulence factors they produce. It has been suggested that the detection of phage elements surrounding toxin genes, horizontal and lateral gene transfer events, and plasmid shuffling occurrences may be some of the reasons that virulence factor genes have so many analogs throughout the bacterial kingdom. Comparison of virulence factors of Photorhabdus, and Bacillus, two bacteria with dissimilar life styles opens the possibility of re-examining newly discovered toxins for novel tissue targets. For example, nematodes residing in the hemolymph may release bacteria with virulence factors targeting neurons or neuromuscular junctions. The first section of this review focuses on toxins and their context in agriculture. The second describes the mode of action of toxins from common entomopathogens and the third draws comparisons between Gram positive and Gram negative bacteria. The fourth section reviews the implications of the nervous system in biocontrol. PMID:24634779

Castagnola, Anaïs; Stock, S. Patricia

2014-01-01

402

PCR primers and probes for the 16S rRNA gene of most species of pathogenic bacteria, including bacteria found in cerebrospinal fluid.  

PubMed Central

A set of broad-range PCR primers for the 16S rRNA gene in bacteria were tested, along with three series of oligonucleotide probes to detect the PCR product. The first series of probes is broad in range and consists of a universal bacterial probe, a gram-positive probe, a Bacteroides-Flavobacterium probe, and two probes for other gram-negative species. The second series was designed to detect PCR products from seven major bacterial species or groups frequently causing meningitis: Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, S. agalactiae, Escherichia coli and other enteric bacteria, Listeria monocytogenes, and Staphylococcus aureus. The third series was designed for the detection of DNA from species or genera commonly considered potential contaminants of clinical samples, including cerebrospinal fluid (CSF): Bacillus, Corynebacterium, Propionibacterium, and coagulase-negative Staphylococcus spp. The primers amplified DNA from all 124 different species of bacteria tested. Southern hybridization testing of the broad-range probes with washes containing 3 M tetramethylammonium chloride indicated that this set of probes correctly identified all but two of the 102 bacterial species tested, the exceptions being Deinococcus radiopugnans and Gardnerella vaginalis. The gram-negative and gram-positive probes hybridized to isolates of two newly characterized bacteria, Alloiococcus otitis and Rochalimaea henselii, as predicted by Gram stain characteristics. The CSF pathogen and contaminant probe sequences were compared with available sequence information and with sequencing data for 32 different species. Testing of the CSF pathogen and contaminant probes against DNA from over 60 different strains indicated that, with the exception of the coagulase-negative Staphylococcus probes, these probes provided the correct identification of bacterial species known to be found in CSF. Images PMID:7512093

Greisen, K; Loeffelholz, M; Purohit, A; Leong, D

1994-01-01

403

A novel compound from the marine bacterium Bacillus pumilus S6-15 inhibits biofilm formation in Gram-positive and Gram-negative species  

Microsoft Academic Search

Biofilm formation is a critical problem in nosocomial infections and in the aquaculture industries and biofilms show high resistance to antibiotics. The aim of the present study was to reveal a novel anti-biofilm compound from marine bacteria against antibiotic resistant Gram-positive and Gram-negative biofilms. The bacterial extract (50 ?g ml) of S6-01 (Bacillus indicus = MTCC 5559) showed 80–90% biofilm inhibition against Escherichia

Chari Nithya; Muthu Gokila Devi; Shunmugiah Karutha Pandian

2011-01-01

404

Modeling Political Populations with Bacteria  

NASA Astrophysics Data System (ADS)

Results from lattice-based simulations of micro-environments with heterogeneous nutrient resources reveal that competition between wild-type and GASP rpoS819 strains of E. Coli offers mutual benefit, particularly in nutrient deprived regions. Our computational model spatially maps bacteria populations and energy sources onto a set of 3D lattices that collectively resemble the topology of North America. By implementing Wright-Fishcer re- production into a probabilistic leap-frog scheme, we observe populations of wild-type and GASP rpoS819 cells compete for resources and, yet, aid each other's long term survival. The connection to how spatial political ideologies map in a similar way is discussed.

Cleveland, Chris; Liao, David

2011-03-01

405

MICROBIOLOGY: How Bacteria Change Gear  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Many species of bacteria form biofilms, slimy carpets a fraction of a millimeter thick that appear on rocks, leaves, pipes, teeth--pretty much any place that has a supply of nutrients and water. Cells must first attach to a surface, which in many species requires swimming propelled by rotating helical flagella (1). Two things typically happen next. Cells stop expressing genes that encode components of the flagellum, and they secrete a sticky matrix of polysaccharides that holds them together on the surface (2). Once at a surface, swimming may be a hindrance rather than a help, and an inverse relationship between swimming and attachment has been seen in many diverse species (3). Bacterial motility is arrested when a protein that acts as a clutch disables rotation of the flagellar motor.

Richard M. Berry (University of Oxford; Department of Physics, Clarendon Lab)

2008-06-20

406

Genetic diversity of siderophore-producing bacteria of tobacco rhizosphere.  

PubMed

The genetic diversity of siderophore-producing bacteria of tobacco rhizosphere was studied by amplified ribosomal DNA restriction analysis (ARDRA), 16S rRNA sequence homology and phylogenetics analysis methods. Studies demonstrated that 85% of the total 354 isolates produced siderophores in iron limited liquid medium. A total of 28 ARDRA patterns were identified among the 299 siderophore-producing bacterial isolates. The 28 ARDRA patterns represented bacteria of 14 different genera belonging to six bacterial divisions, namely ?-, ?-, ?-Proteobacteria, Sphingobacteria, Bacilli, and Actinobacteria. Especially, ?-Proteobacteria consisting of Pseudomonas, Enterobacter, Serratia, Pantoea, Erwinia and Stenotrophomonas genus encountered 18 different ARDRA groups. Results also showed a greater siderophore-producing bacterial diversity than previous researches. For example, Sphingobacterium (isolates G-2-21-1 and G-2-27-2), Pseudomonas poae (isolate G-2-1-1), Enterobacter endosymbiont (isolates G-2-10-2 and N-5-10), Delftia acidovorans (isolate G-1-15), and Achromobacter xylosoxidans (isolates N-46-11HH and N-5-20) were reported to be able to produce siderophores under low-iron conditions for the first time. Gram-negative isolates were more frequently encountered, with more than 95% total frequency. For Gram-positive bacteria, the Bacillus and Rhodococcus were the only two genera, with 1.7% total frequency. Furthermore, the Pseudomonas and Enterobacter were dominant in this environment, with 44.5% and 24.7% total frequency, respectively. It was also found that 75 percent of the isolates that had the high percentages of siderophore units (% between 40 and 60) belonged to Pseudomonas. Pseudomonas sp. G-229-21 screened out in this study may have potential to apply to low-iron soil to prevent plant soil-borne fungal pathogen diseases. PMID:24031358

Tian, Fang; Ding, Yanqin; Zhu, Hui; Yao, Liangtong; Du, Binghai

2009-04-01

407

GROWTH INHIBITION OF MEDICALLY ANTIBIOTIC RESISTANT BACTERIA BY SPONGE-ASSOCIATED BACTERIA  

Microsoft Academic Search

The improper and uncontrolled uses of antibiotics against pathogenic bacteria have resulted in the occurrence of Multi Drugs Resistant bacteria. There is now an urgency to find alternative antibiotics to combat these bacteria. The metabolites from microorganisms are a rapidly growing field, due, at least in part, to the suspicion that a number of metabolites obtained from algae and invertebrates

Ocky Karna Radjasa

2008-01-01

408

Fighting infections due to multidrug-resistant Gram-positive pathogens.  

PubMed

Growing bacterial resistance in Gram-positive pathogens means that what were once effective and inexpensive treatments for infections caused by these bacteria are now being seriously questioned, including penicillin and macrolides for use against pneumococcal infections and-in hospitals-oxacillin for use against staphylococcal infections. As a whole, multidrug-resistant (MDR) Gram-positive pathogens are rapidly becoming an urgent and sometimes unmanageable clinical problem. Nevertheless, and despite decades of research into the effects of antibiotics, the actual risk posed to human health by antibiotic resistance has been poorly defined; the lack of reliable data concerning the outcomes resulting from antimicrobial resistance stems, in part, from problems with study designs and the methods used in resistence determination. Surprisingly little is known, too, about the actual effectiveness of the many types of intervention aimed at controlling antibiotic resistance. New antibiotics active against MDR Gram-positive pathogens have been recently introduced into clinical practice, and the antibiotic pipeline contains additional compounds at an advanced stage of development, including new glycopeptides, new anti-methicillin-resistant Staphylococcus aureus (MRSA) beta-lactams, and new diaminopyrimidines. Many novel antimicrobial agents are likely to be niche products, endowed with narrow antibacterial spectra and/or targeted at specific clinical problems. Therefore, an important educational goal will be to change the current, long-lasting attitudes of both physicians and customers towards broad-spectrum and multipurpose compounds. Scientific societies, such as the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), must play a leading role in this process. PMID:19335367

Cornaglia, G

2009-03-01

409

Recognition of U-rich RNA by Hfq from the Gram-positive pathogen Listeria monocytogenes  

PubMed Central

Hfq is a post-transcriptional regulator that binds U- and A-rich regions of sRNAs and their target mRNAs to stimulate their annealing in order to effect translation regulation and, often, to alter their stability. The functional importance of Hfq and its RNA-binding properties are relatively well understood in Gram-negative bacteria, whereas less is known about the RNA-binding properties of this riboregulator in Gram-positive species. Here, we describe the structure of Hfq from the Gram-positive pathogen Listeria monocytogenes in its RNA-free form and in complex with a U6 oligoribonucleotide. As expected, the protein takes the canonical hexameric toroidal shape of all other known Hfq structures. The U6 RNA binds on the “proximal face” in a pocket formed by conserved residues Q9, N42, F43, and K58. Additionally residues G5 and Q6 are involved in protein-nucleic and inter-subunit contacts that promote uracil specificity. Unlike Staphylococcus aureus (Sa) Hfq, Lm Hfq requires magnesium to bind U6 with high affinity. In contrast, the longer oligo-uridine, U16, binds Lm Hfq tightly in the presence or absence of magnesium, thereby suggesting the importance of additional residues on the proximal face and possibly the lateral rim in RNA interaction. Intrinsic tryptophan fluorescence quenching (TFQ) studies reveal, surprisingly, that Lm Hfq can bind (GU)3G and U6 on its proximal and distal faces, indicating a less stringent adenine-nucleotide specificity site on the distal face as compared to the Gram-positive Hfq proteins from Sa and Bacillus subtilis and suggesting as yet uncharacterized RNA-binding modes on both faces. PMID:25150227

Kovach, Alexander R.; Hoff, Kirsten E.; Canty, John T.; Orans, Jillian

2014-01-01

410

Mitochondria: A target for bacteria.  

PubMed

Eukaryotic cells developed strategies to detect and eradicate infections. The innate immune system, which is the first line of defence against invading pathogens, relies on the recognition of molecular patterns conserved among pathogens. Pathogen associated molecular pattern binding to pattern recognition receptor triggers the activation of several signalling pathways leading to the establishment of a pro-inflammatory state required to control the infection. In addition, pathogens evolved to subvert those responses (with passive and active strategies) allowing their entry and persistence in the host cells and tissues. Indeed, several bacteria actively manipulate immune system or interfere with the cell fate for their own benefit. One can imagine that bacterial effectors can potentially manipulate every single organelle in the cell. However, the multiple functions fulfilled by mitochondria especially their involvement in the regulation of innate immune response, make mitochondria a target of choice for bacterial pathogens as they are not only a key component of the central metabolism through ATP production and synthesis of various biomolecules but they also take part to cell signalling through ROS production and control of calcium homeostasis as well as the control of cell survival/programmed cell death. Furthermore, considering that mitochondria derived from an ancestral bacterial endosymbiosis, it is not surprising that a special connection does exist between this organelle and bacteria. In this review, we will discuss different mitochondrial functions that are affected during bacterial infection as well as different strategies developed by bacterial pathogens to subvert functions related to calcium homeostasis, maintenance of redox status and mitochondrial morphology. PMID:25707982

Lobet, Elodie; Letesson, Jean-Jacques; Arnould, Thierry

2015-04-01

411

Characteristics of CDC group 3 and group 5 coryneform bacteria isolated from clinical specimens and assignment to the genus Dermabacter.  

PubMed Central

Over a 1-year period, 11 isolates (including 5 from blood cultures) of the recently described CDC group 3 and group 5 coryneform bacteria were derived from clinical specimens and compared with reference strains. Biochemical characteristics indicated a very close relationship between CDC group 3 and group 5 coryneform bacteria. The ability of CDC group 3 and the inability of CDC group 5 coryneform bacteria to ferment xylose were the only reactions that were different for the two taxa. Chemotaxonomic features of the two groups included the presence of meso-diaminopimelic acid, a lack of mycolic acids, and the presence of predominantly branched cellular fatty acids, a combination found among gram-positive rods only in Brevibacterium spp., Brachybacterium faecium, and Dermabacter hominis. 16S rRNA gene sequence analysis revealed that CDC group 3 and group 5 coryneform bacteria are members of the genus Dermabacter, which to date has been isolated exclusively from human skin. PMID:8051248

Funke, G; Stubbs, S; Pfyffer, G E; Marchiani, M; Collins, M D

1994-01-01

412

In Vitro Activity of Ceftaroline against 623 Diverse Strains of Anaerobic Bacteria ?  

PubMed Central

The in vitro activities of ceftaroline, a novel, parenteral, broad-spectrum cephalosporin, and four comparator antimicrobials were determined against anaerobic bacteria. Against Gram-positive strains, the activity of ceftaroline was similar to that of amoxicillin-clavulanate and four to eight times greater than that of ceftriaxone. Against Gram-negative organisms, ceftaroline showed good activity against ?-lactamase-negative strains but not against the members of the Bacteroides fragilis group. Ceftaroline showed potent activity against a broad spectrum of anaerobes encountered in respiratory, skin, and soft tissue infections. PMID:20100877

Citron, D. M.; Tyrrell, K. L.; Merriam, C. V.; Goldstein, E. J. C.

2010-01-01

413

The Effect of Phylogenetically Different Bacteria on the Fitness of Pseudomonas fluorescens in Sand Microcosms.  

PubMed

In most environments many microorganisms live in close vicinity and can interact in various ways. Recent studies suggest that bacteria are able to sense and respond to the presence of neighbouring bacteria in the environment and alter their response accordingly. This ability might be an important strategy in complex habitats such as soils, with great implications for shaping the microbial community structure. Here, we used a sand microcosm approach to investigate how Pseudomonas fluorescens Pf0-1 responds to the presence of monocultures or mixtures of two phylogenetically different bacteria, a Gram-negative (Pedobacter sp. V48) and a Gram-positive (Bacillus sp. V102) under two nutrient conditions. Results revealed that under both nutrient poor and nutrient rich conditions confrontation with the Gram-positive Bacillus sp. V102 strain led to significant lower cell numbers of Pseudomonas fluorescens Pf0-1, whereas confrontation with the Gram-negative Pedobacter sp. V48 strain did not affect the growth of Pseudomonas fluorescens Pf0-1. However, when Pseudomonas fluorescens Pf0-1 was confronted with the mixture of both strains, no significant effect on the growth of Pseudomonas fluorescens Pf0-1 was observed. Quantitative real-time PCR data showed up-regulation of genes involved in the production of a broad-spectrum antibiotic in Pseudomonas fluorescens Pf0-1 when confronted with Pedobacter sp. V48, but not in the presence of Bacillus sp. V102. The results provide evidence that the performance of bacteria in soil depends strongly on the identity of neighbouring bacteria and that inter-specific interactions are an important factor in determining microbial community structure. PMID:25774766

Tyc, Olaf; Wolf, Alexandra B; Garbeva, Paolina

2015-01-01

414

The Effect of Phylogenetically Different Bacteria on the Fitness of Pseudomonas fluorescens in Sand Microcosms  

PubMed Central

In most environments many microorganisms live in close vicinity and can interact in various ways. Recent studies suggest that bacteria are able to sense and respond to the presence of neighbouring bacteria in the environment and alter their response accordingly. This ability might be an important strategy in complex habitats such as soils, with great implications for shaping the microbial community structure. Here, we used a sand microcosm approach to investigate how Pseudomonas fluorescens Pf0-1 responds to the presence of monocultures or mixtures of two phylogenetically different bacteria, a Gram-negative (Pedobacter sp. V48) and a Gram-positive (Bacillus sp. V102) under two nutrient conditions. Results revealed that under both nutrient poor and nutrient rich conditions confrontation with the Gram-positive Bacillus sp. V102 strain led to significant lower cell numbers of Pseudomonas fluorescens Pf0-1, whereas confrontation with the Gram-negative Pedobacter sp. V48 strain did not affect the growth of Pseudomonas fluorescens Pf0-1. However, when Pseudomonas fluorescens Pf0-1 was confronted with the mixture of both strains, no significant effect on the growth of Pseudomonas fluorescens Pf0-1 was observed. Quantitative real-time PCR data showed up-regulation of genes involved in the production of a broad-spectrum antibiotic in Pseudomonas fluorescens Pf0-1 when confronted with Pedobacter sp. V48, but not in the presence of Bacillus sp. V102. The results provide evidence that the performance of bacteria in soil depends strongly on the identity of neighbouring bacteria and that inter-specific interactions are an important factor in determining microbial community structure. PMID:25774766

Tyc, Olaf; Wolf, Alexandra B.; Garbeva, Paolina

2015-01-01

415

An overview of the alpha-, beta- and gamma-carbonic anhydrases from Bacteria: can bacterial carbonic anhydrases shed new light on evolution of bacteria?  

PubMed

Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes which catalyze a simple but physiologically crucial reaction in all life Domains, the carbon dioxide hydration to bicarbonate and protons: CO2?+?H2O ? [Formula: see text](?)+?H(+). These enzymes are involved in many physiologic processes, such as photosynthesis, respiration, CO2 transport, as well as metabolism of xenobiotics. Five different, genetically distinct CA families are known to date: the ?-, ?-, ?-, ?- and ?-CAs. ?-, ?- and ?-CAs use Zn(II) ions at the active site, the ?-CAs are probably Fe(II) enzymes (but they are active also with bound Zn(II) or Co(II) ions), whereas the ?-class uses Cd(II) or Zn(II) to perform the physiologic reaction catalysis. Bacteria encode for enzymes belonging to the ?-, ?-, and ?-CA classes. They contain zinc ion (Zn(2+)) in their active site, coordinated by three histidine residues and a water molecule/hydroxide ion (in the ? and ?) or by two cysteine and one histidine residues (in the ? class), with the fourth ligand being a water molecule/hydroxide ion. Here we propose that bacterial CAs can be used as markers for understanding the evolution and genetic variability of the Gram-positive and Gram-negative bacteria. We addressed several questions such as: (1) why are ?-CAs present only in the genome of Gram-negative bacteria; (2) why are ?-CAs not present in all Gram-negative bacteria; (3) why do Bacteria show an intricate pattern of CA gene expression; (4) what are the physiologic roles of such diverse CAs in these prokaryotes. We proposed possible answers to the previous questions. Moreover, we speculated on the evolution of the CA classes (?, ? and ?) identified in the Gram-negative and -positive bacteria. Our main hypothesis is that from the ancestral Ur-CA, the ?-class arose first, followed by the ?-class; the ?-class CAs came last it is found only in the Gram-negative bacteria. PMID:24766661

Capasso, Clemente; Supuran, Claudiu T

2015-04-01

416

Exploiting what phage have evolved to control gram-positive pathogens  

PubMed Central

In the billion years that bacteriophage (or phage) have existed together with bacteria the phage have evolved systems that may be exploited for our benefit. One of these is the lytic system used by the phage to release their progeny from an infected bacterium. Endolysins (or lysins) are highly evolved enzymes in the lytic system produced to cleave essential bonds in the bacterial cell wall peptidoglycan for progeny release. Small quantities of purified recombinant lysin added externally to gram-positive bacteria results in immediate lysis causing log-fold death of the target bacterium. Lysins have now been used successfully in a variety of animal models to control pathogenic antibiotic resistant bacteria found on mucosal surfaces and in infected tissues. The advantages over antibiotics are their specificity for the pathogen without disturbing the normal flora, the low chance of bacterial resistance, and their ability to kill colonizing pathogens on mucosal surfaces, a capacity previously unavailable. Lysins therefore, may be a much-needed anti-infective (or enzybiotic) in an age of mounting antibiotic resistance. PMID:23050211

Fischetti, Vincent A.

2011-01-01

417

Energy transduction in lactic acid bacteria  

Microsoft Academic Search

In the discovery of some general principles of energy transduction, lactic acid bacteria have played an important role. In this review, the energy transducing processes of lactic acid bacteria are discussed with the emphasis on the major developments of the past 5 years. This work not only includes the biochemistry of the enzymes and the bioenergetics of the processes, but

Bert Poolman

1993-01-01

418

Proteolytic systems in lactic acid bacteria  

Microsoft Academic Search

The proteolytic systems of lactic acid bacteria are important as a means of making protein and peptide N available for growth and as part of the curing or maturation processes which give foods their characteristic rheological and organoleptic properties. The proteolytic systems of lactic acid bacteria are described in relation to their growth and their functions in protein-rich foods. Their

Barry A. Law; Jens Kolstad; Pekka Varmanen; Bert Poolman I; Wil N. Konings

1983-01-01

419

Rock magnetic properties of uncultured magnetotactic bacteria  

Microsoft Academic Search

Understanding the magnetic properties of magnetite crystals (Fe3O4) produced by magnetotactic bacteria (MTBs) is of fundamental interest in fields of geosciences, biomineralization, fine particle magnetism, and planetary sciences. The database of bulk magnetic measurements on MTBs is, however, still too sparse to allow for generalizations due to difficulties in obtaining bacteria cells in sufficient quantities from natural environments, and the

Yongxin Pan; Nikolai Petersen; Michael Winklhofer; Alfonso F. Davila; Qingsong Liu; Thomas Frederichs; Marianne Hanzlik; Rixiang Zhu

2005-01-01

420

Metal uptake and separation using magnetotactic bacteria  

Microsoft Academic Search

Magnetotactic bacteria align themselves with the Earth's magnetic field enabling them to navigate towards their ideal environment in sediments of ponds, streams or rivers in which they live. A magnetotactic spirillum has been used to study uptake and separation of various heavy metals from solution at low ppm levels. By applying a low, focusing magnetic field, metal loaded magnetotactic bacteria

A. S. Bahaj; P. A. B. James; I. W. Croudace

1994-01-01

421

Analyzing Arthropods for the Presence of Bacteria  

PubMed Central

Bacteria within arthropods can be identified using culture-independent methods. This unit describes protocols for surface sterilization of arthropods, DNA extraction of whole bodies and tissues, touchdown PCR amplification using 16S rDNA general bacteria primers and profiling the bacterial community using denaturing gradient gel electrophoresis. PMID:23408130

Andrews, Elizabeth S.

2013-01-01

422

Evolutionary Genomics of Lactic Acid Bacteria  

Microsoft Academic Search

The lactic acid bacteria (LAB) might be the most numerous group of bacteria linked to humans. They are naturally asso- ciated with mucosal surfaces, particularly the gastrointestinal tract, and are also indigenous to food-related habitats, includ- ing plant (fruits, vegetables, and cereal grains), wine, milk, and meat environments (60, 61). The LAB include both important pathogens, e.g., several Streptococcus species,

Kira S. Makarova; Eugene V. Koonin

2007-01-01

423

Comparative genomics of the lactic acid bacteria  

Technology Transfer Automated Retrieval System (TEKTRAN)

Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacter...

424

Protein glycosylation in bacteria: sweeter than ever  

Microsoft Academic Search

Investigations into bacterial protein glycosylation continue to progress rapidly. It is now established that bacteria possess both N-linked and O-linked glycosylation pathways that display many commonalities with their eukaryotic and archaeal counterparts as well as some unexpected variations. In bacteria, protein glycosylation is not restricted to pathogens but also exists in commensal organisms such as certain Bacteroides species, and both

Harald Nothaft; Christine M. Szymanski

2010-01-01

425

Genome structure of bacteria: Uniformity or diversity?  

SciTech Connect

This paper is a survey of data indicating that, in contrast to widely adopted ideas, bacterial chromosomes and plasmids are not only circular, but also linear. Moreover, certain bacteria contain at least two different chromosomes per cell. Examples of other unusual genome properties in certain representatives of bacteria are also considered. 78 refs., 4 figs.

Prozorov, A.A. [Vavilov Institute of General Genetics, Moscow (Russian Federation)

1995-06-01

426

Sexual Isolation and Speciation in Bacteria  

Microsoft Academic Search

Like organisms from all other walks of life, bacteria are capable of sexual recombination. However, unlike most plants and animals, bacteria recombine only rarely, and when they do they are extremely promiscuous in their choice of sexual partners. There may be no absolute constraints on the evolutionary distances that can be traversed through recombination in the bacterial world, but interspecies

Frederick M. Cohan

2002-01-01

427

Symbiosis of methanogenic bacteria and sapropelic protozoa  

Microsoft Academic Search

Fluorescent bacteria were demonstrated to be abundantly spread as single cells throughout the cytoplasm of the giant amoeba Pelomyxa palustris, the sapropelic ciliate Metopus striatus and six other anaerobic protozoa examined. The endosymbionts of P. palustris and M. striatus were identified as methanogenic bacteria on the basis of the presence of the deazaflavin coenzyme F420 and the pterin compound F342.

Johan J. A. van Bruggen; Claudius K. Stumm; Godfried D. Vogels

1983-01-01

428

Bacteria are like Popeye the sailor man  

NSDL National Science Digital Library

Popeye the sailor man and infection-causing bacteria have something in common -- they need to consume iron to perform their best. In cartoons, Popeye gets his iron from spinach. New research shows exactly where the bacteria that often cause pneumonia get their iron.

American Association for the Advancement of Science (AAAS; )

2004-09-10

429

Immunology Taught by Bacteria Russell E. Vance  

E-print Network

Immunology Taught by Bacteria Russell E. Vance Received: 11 March 2010 /Accepted: 12 March 2010 by studies of the living, virulent pathogens themselves. Methods and Findings Here, I review what one multiple pathogenic bacteria. Conclusion Thus, immunology taught by L. pneumophila may lead to a more

Vance,. Russell

430

Method of dispersing a hydrocarbon using bacteria  

DOEpatents

A new protozoan derived microbial consortia and method for their isolation are provided. The isolated consortia and bacteria are useful for treating wastes such as trichloroethylene and trinitrotoluene. The isolated consortia, bacteria, and dispersants are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

Tyndall, R.L.

1996-09-24

431

Method of dispersing a hydrocarbon using bacteria  

DOEpatents

New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

Tyndall, Richard L. (Clinton, TN)

1996-01-01

432

Why and How Bacteria Localize Proteins  

NSDL National Science Digital Library

Despite their small size, bacteria have a remarkably intricate internal organization. Bacteria deploy proteins and protein complexes to particular locations and do so in a dynamic manner in lockstep with the organized deployment of their chromosome. The dynamic subcellular localization of protein complexes is an integral feature of regulatory processes of bacterial cells.

L. Shapiro (Stanford University; Department of Developmental Biology)

2009-11-27

433

Systemic resistance induced by rhizosphere bacteria  

Microsoft Academic Search

Nonpathogenic rhizobacteria can induce a systemic resistance in plants that is phenotypically similar to pathogen-induced systemic acquired resistance (SAR). Rhizobacteria-mediated induced systemic resistance (ISR) has been demonstrated against fungi, bacteria, and viruses in Arabidopsis, bean, carnation, cucumber, radish, tobacco, and tomato under conditions in which the inducing bacteria and the challenging pathogen remained spatially separated. Bacterial strains differ in their

L. C. van Loon; P. A. H. M. Bakker; C. M. J. Pieterse

1998-01-01

434

NClassG+: A classifier for non-classically secreted Gram-positive bacterial proteins  

PubMed Central

Background Most predictive methods currently available for the identification of protein secretion mechanisms have focused on classically secreted proteins. In fact, only two methods have been reported for predicting non-classically secreted proteins of Gram-positive bacteria. This study describes the implementation of a sequence-based classifier, denoted as NClassG+, for identifying non-classically secreted Gram-positive bacterial proteins. Results Several feature-based classifiers were trained using different sequence transformation vectors (frequencies, dipeptides, physicochemical factors and PSSM) and Support Vector Machines (SVMs) with Linear, Polynomial and Gaussian kernel functions. Nested k-fold cross-validation (CV) was applied to select the best models, using the inner CV loop to tune the model parameters and the outer CV group to compute the error. The parameters and Kernel functions and the combinations between all possible feature vectors were optimized using grid search. Conclusions The final model was tested against an independent set not previously seen by the model, obtaining better predictive performance compared to SecretomeP V2.0 and SecretPV2.0 for the identification of non-classically secreted proteins. NClassG+ is freely available on the web at http://www.biolisi.unal.edu.co/web-servers/nclassgpositive/ PMID:21235786

2011-01-01

435

Structural Features of Manganese Precipitating Bacteria  

NASA Astrophysics Data System (ADS)

Studies of biological communities of the past (and their associated activities) are usually dependent upon preservation of fossil material. With bacteria this rarely occurs because of the absence of sufficient fossilizable cellular material. However, some bacteria deposit metabolic products that can, conditions allowing, be preserved indefinitely. In particular, manganese and iron depositing bacteria have the capacity to form preservable microfossils. In order to better understand these microfossils of the past, we have examined present day morphologies of manganese oxidizing bacteria. These bacteria are highly pleomorphic, depending on the growth medium, the age of the culture, and the extent of manganese oxidation. Transmission electron microscopy indicates that manganese may be deposited either intra-or extra-cellularly. The prognosis of the use of morphological information for the interpretation of ancient and modern manganese deposits is discussed.

Nealson, Kenneth H.; Tebo, Bradley

1980-06-01

436

Filamentous bacteria existence in aerobic granular reactors.  

PubMed

Filamentous bacteria are associated to biomass settling problems in wastewater treatment plants. In systems based on aerobic granular biomass they have been proposed to contribute to the initial biomass aggregation process. However, their development on mature aerobic granular systems has not been sufficiently studied. In the present research work, filamentous bacteria were studied for the first time after long-term operation (up to 300 days) of aerobic granular systems. Chloroflexi and Sphaerotilus natans have been observed in a reactor fed with synthetic wastewater. These filamentous bacteria could only come from the inoculated sludge. Thiothrix and Chloroflexi bacteria were observed in aerobic granular biomass treating wastewater from a fish canning industry. Meganema perideroedes was detected in a reactor treating wastewater from a plant processing marine products. As a conclusion, the source of filamentous bacteria in these mature aerobic granular systems fed with industrial effluents was the incoming wastewater. PMID:25533039

Figueroa, M; Val Del Río, A; Campos, J L; Méndez, R; Mosquera-Corral, A

2015-05-01

437

HYDROCARBON-DEGRADING BACTERIA AND SURFACTANT ACTIVITY  

SciTech Connect

Fate of benzene ethylbenzene toluene xylenes (BTEX) compounds through biodegradation was investigated using two different bacteria, Ralstonia picketti (BP-20) and Alcaligenes piechaudii (CZOR L-1B). These bacteria were isolated from extremely polluted petroleum hydrocarbon contaminated soils. PCR and Fatty Acid Methyl Ester (FAME) were used to identify the isolates. Biodegradation was measured using each organism individually and in combination. Both bacteria were shown to degrade each of the BTEX compounds. Alcaligenes piechaudii biodegraded BTEXs more efficiently while mixed with BP-20 and individually. Biosurfactant production was observed by culture techniques. In addition 3-hydroxy fatty acids, important in biosurfactant production, was observed by FAME analysis. In the all experiments toluene and m+p- xylenes were better growth substrates for both bacteria than the other BTEX compounds. In addition, the test results indicate that the bacteria could contribute to bioremediation of aromatic hydrocarbons (BTEX) pollution increase biodegradation through the action by biosurfactants.

Brigmon, R; Topher Berry, T; Grazyna A. Plaza, G; jacek Wypych, j

2006-08-15

438

Chemotactic selection of pollutant degrading soil bacteria  

DOEpatents

A method is described for identifying soil microbial strains which may be bacterial degraders of pollutants. This method includes: Placing a concentration of a pollutant in a substantially closed container; placing the container in a sample of soil for a period of time ranging from one minute to several hours; retrieving the container and collecting its contents; microscopically determining the identity of the bacteria present. Different concentrations of the pollutant can be used to determine which bacteria respond to each concentration. The method can be used for characterizing a polluted site or for looking for naturally occurring biological degraders of the pollutant. Then bacteria identified as degraders of the pollutant and as chemotactically attracted to the pollutant are used to innoculate contaminated soil. To enhance the effect of the bacteria on the pollutant, nutrients are cyclicly provided to the bacteria then withheld to alternately build up the size of the bacterial colony or community and then allow it to degrade the pollutant.

Hazen, T.C.

1991-03-04

439

Interaction of Intraleukocytic Bacteria and Antibiotics  

PubMed Central

Bacteria that survive inside polymorphonuclear neutrophils (PMN) following phagocytosis are protected from the bactericidal action of most antibiotics. Two possible explanations are altered metabolism by intraleukocytic bacteria or failure of antibiotics to enter the phagosome. The oxygen consumption of intraleukocytic and extraleukocytic bacteria was measured as an index of bacterial metabolism. PMN respiration and bactericidal activity were suppressed with large doses of hydrocortisone and extraleukocytic bacterial oxygen consumption was abolished by the addition of lysostaphin. Intraleukocytic bacterial continued to consume oxygen suggesting that surviving ingested micro-organisms are metabolically active. Neither penicillin (which cannot kill intraleukocytic bacteria) nor rifampin (which can kill intraleukocytic bacteria) was bactericidal for staphylococci at 5°C. Thus, rifampin is not uniquely able to kill “resting” bacteria. Intraleukocytic or extraleukocytic Staphylococcus aurens were incubated with [benzyl-14C]penicillin for 2 h at 37°C. Live intraleukocytic bacteria bound only 13% as much penicillin as live bacteria incubated with killed PMN. To measure the penetration of antibiotics into PMN, [14C]rifampin and [14C]penicillin were measured in leukocyte pellets and in the supernatant fluid. The total water space in the pellets was quantitated using tritium water and the extracellular water space was measured using Na235SO4. All penicillin associated with the cell pellet could be accounted for in extracellular water. Thus penicillin was completely excluded from the leukocytes. Rifampin was concentrated in the cell pellet 2.2 times when compared with the supernatant concentration. These studies suggest that a likely explanation for the survival of phagocytized bacteria in the presence of high concentrations of most antibiotics is the inability of the antibiotic to enter the phagocyte. Rifampin, which is highly lipid soluble, can enter leukocytes and kill intracellular bacteria. PMID:4718959

Mandell, Gerald L.

1973-01-01

440

Aspects of eukaryotic-like signaling in Gram-positive cocci: a focus on virulence  

PubMed Central

Living organisms adapt to the dynamic external environment for their survival. Environmental adaptation in prokaryotes is thought to be primarily accomplished by signaling events mediated by two-component systems, consisting of histidine kinases and response regulators. However, eukaryotic-like serine/threonine kinases (STKs) have recently been described to regulate growth, antibiotic resistance and virulence of pathogenic bacteria. This article summarizes the role of STKs and their cognate phosphatases (STPs) in Gram-positive cocci that cause invasive infections in humans. Given that a large number of inhibitors to eukaryotic STKs are approved for use in humans, understanding how serine/threonine phosphorylation regulates virulence and antibiotic resistance will be beneficial for the development of novel therapeutic strategies against bacterial infections. PMID:21797690

Burnside, Kellie; Rajagopal, Lakshmi

2011-01-01

441

Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria  

PubMed Central

Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous i