Sample records for bacteria gram-positive bacteria

  1. Antimicrobial Resistance in Gram-Positive Bacteria

    Microsoft Academic Search

    Louis B. Rice

    2006-01-01

    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

  2. Hyaluronidases of Gram-positive bacteria

    Microsoft Academic Search

    Wayne L. Hynes; Sheryl Lynne Walton

    2000-01-01

    Bacterial hyaluronidases, enzymes capable of breaking down hyaluronate, are produced by a number of pathogenic Gram-positive bacteria that initiate infections at the skin or mucosal surfaces. Since reports of the hyaluronidases first appeared, there have been numerous suggestions as to the role of the enzyme in the disease process. Unlike some of the other more well studied virulence factors, much

  3. Lipoprotein biogenesis in Gram-positive bacteria: knowing when to

    E-print Network

    Palmer, Tracy

    Lipoprotein biogenesis in Gram- positive bacteria: knowing when to hold `em, knowing when to fold Tyne, NE1 8ST, UK Gram-positive bacterial lipoproteins are a functionally diverse and important class of these proteins, their role in virulence in Gram-positive bacteria and their potential as vaccine candidates

  4. 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

  5. Methods for targetted mutagenesis in gram-positive bacteria

    DOEpatents

    Yang, Yunfeng

    2014-05-27

    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.

  6. Heterogenetic Antigens of Gram-Positive Bacteria1

    PubMed Central

    Chorpenning, Frank W.; Dodd, Matthew C.

    1966-01-01

    Chorpenning, Frank W. (The Ohio State University, Columbus), and Matthew C. Dodd. Heterogenetic antigens of gram-positive bacteria. J. Bacteriol. 91:1440–1445. 1966.—Soluble antigens obtained by various methods from gram-positive bacteria were used to modify erythrocytes whose hemagglutinating reactions with immune rabbit sera and normal human sera were then studied. Antigens from all gram-positive organisms studied except corynbacteria altered red cells, causing them to react with specific bacterial antisera and with normal human sera; however, cross-absorption and inhibition tests indicated that at least three different specificites were involved. One of these antigens seemed to be similar to Rantz's streptococcal NSS, which is shared with Staphylococcus aureus and Bacillus spp., and is therefore heterogenetic. Another was found in streptococci but was apparently not present in S. aureus and Bacillus spp. A third antigen, also heterogenetic, appeared to be shared by several species of Bacillus and by S. aureus, but not by streptococci or any gram-negative bacteria. The third antigen was heat-stable at pH 8.0, and appeared to be essentially polysaccharide in nature. Normal human sera varied in their content of antibodies which reacted with erythrocytes modified by extracts from gram-positive bacteria. Whereas some sera reacted very broadly with red cells modified by extracts of practically any gram-positive organism, other sera agglutinated only cells which had been modified by streptococcal antigen. PMID:4956340

  7. Conjugative Plasmid Transfer in Gram-Positive Bacteria

    PubMed Central

    Grohmann, Elisabeth; Muth, Günther; Espinosa, Manuel

    2003-01-01

    Conjugative transfer of bacterial plasmids is the most efficient way of horizontal gene spread, and it is therefore considered one of the major reasons for the increase in the number of bacteria exhibiting multiple-antibiotic resistance. Thus, conjugation and spread of antibiotic resistance represents a severe problem in antibiotic treatment, especially of immunosuppressed patients and in intensive care units. While conjugation in gram-negative bacteria has been studied in great detail over the last decades, the transfer mechanisms of antibiotic resistance plasmids in gram-positive bacteria remained obscure. In the last few years, the entire nucleotide sequences of several large conjugative plasmids from gram-positive bacteria have been determined. Sequence analyses and data bank comparisons of their putative transfer (tra) regions have revealed significant similarities to tra regions of plasmids from gram-negative bacteria with regard to the respective DNA relaxases and their targets, the origins of transfer (oriT), and putative nucleoside triphosphatases NTP-ases with homologies to type IV secretion systems. In contrast, a single gene encoding a septal DNA translocator protein is involved in plasmid transfer between micelle-forming streptomycetes. Based on these clues, we propose the existence of two fundamentally different plasmid-mediated conjugative mechanisms in gram-positive microorganisms, namely, the mechanism taking place in unicellular gram-positive bacteria, which is functionally similar to that in gram-negative bacteria, and a second type that occurs in multicellular gram-positive bacteria, which seems to be characterized by double-stranded DNA transfer. PMID:12794193

  8. Antimicrobial Peptide Resistance Mechanisms of Gram-Positive Bacteria

    PubMed Central

    McBride, Shonna M.

    2014-01-01

    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

  9. Protein secretion and surface display in Gram-positive bacteria

    PubMed Central

    Schneewind, Olaf; Missiakas, Dominique M.

    2012-01-01

    The cell wall peptidoglycan of Gram-positive bacteria functions as a surface organelle for the transport and assembly of proteins that interact with the environment, in particular, the tissues of an infected host. Signal peptide-bearing precursor proteins are secreted across the plasma membrane of Gram-positive bacteria. Some precursors carry C-terminal sorting signals with unique sequence motifs that are cleaved by sortase enzymes and linked to the cell wall peptidoglycan of vegetative forms or spores. The sorting signals of pilin precursors are cleaved by pilus-specific sortases, which generate covalent bonds between proteins leading to the assembly of fimbrial structures. Other precursors harbour surface (S)-layer homology domains (SLH), which fold into a three-pronged spindle structure and bind secondary cell wall polysaccharides, thereby associating with the surface of specific Gram-positive microbes. Type VII secretion is a non-canonical secretion pathway for WXG100 family proteins in mycobacteria. Gram-positive bacteria also secrete WXG100 proteins and carry unique genes that either contribute to discrete steps in secretion or represent distinctive substrates for protein transport reactions. PMID:22411983

  10. Wall Teichoic Acids of Gram-Positive Bacteria

    PubMed Central

    Brown, Stephanie; Santa Maria, John P.; Walker, Suzanne

    2013-01-01

    The peptidoglycan layers of many gram-positive bacteria are densely functionalized with anionic glycopolymers called wall teichoic acids (WTAs). These polymers play crucial roles in cell shape determination, regulation of cell division, and other fundamental aspects of gram-positive bacterial physiology. Additionally, WTAs are important in pathogenesis and play key roles in antibiotic resistance. We provide an overview of WTA structure and biosynthesis, review recent studies on the biological roles of these polymers, and highlight remaining questions. We also discuss prospects for exploiting WTA biosynthesis as a target for new therapies to overcome resistant infections. PMID:24024634

  11. Conjugative type IV secretion systems in Gram-positive bacteria

    PubMed Central

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

    2013-01-01

    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

  12. The Tat system of Gram-positive bacteria.

    PubMed

    Goosens, Vivianne J; Monteferrante, Carmine G; van Dijl, Jan Maarten

    2014-08-01

    The twin-arginine protein translocation (Tat) system has a unique ability to translocate folded and co-factor-containing proteins across lipid bilayers. The Tat pathway is present in bacteria, archaea and in the thylakoid membranes of chloroplasts and, depending on the organism and environmental conditions, it can be deemed important for cell survival, virulence or bioproduction. This review provides an overview of the current understanding of the Tat system with specific focus on Gram-positive bacteria. The 'universal minimal Tat system' is composed of a TatA and a TatC protein. However, this pathway is more commonly composed of two TatA-like proteins and one TatC protein. Often the TatA-like proteins have diverged to have two different functions and, in this case, the second TatA-like protein is usually referred to as TatB. The correct folding and/or incorporation of co-factors are requirements for translocation, and the known quality control mechanisms are examined in this review. A number of examples of crosstalk between the Tat system and other protein transport systems, such as the Sec-YidC translocon and signal peptidases or sheddases are also discussed. Further, an overview of specific Gram-positive bacterial Tat systems found in monoderm and diderm species is detailed. Altogether, this review highlights the unique features of Gram-positive bacterial Tat systems and pinpoints key questions that remain to be addressed in future research. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey. PMID:24140208

  13. Current and novel antibiotics against resistant Gram-positive bacteria

    PubMed Central

    Perez, Federico; Salata, Robert A; Bonomo, Robert A

    2008-01-01

    The challenge posed by resistance among Gram-positive bacteria, epitomized by methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) and vancomycin-intermediate and -resistant S. aureus (VISA and VRSA) is being met by a new generation of antimicrobials. This review focuses on the new ?-lactams with activity against MRSA (ceftobiprole and ceftaroline) and on the new glycopeptides (oritavancin, dalbavancin, and telavancin). It will also consider the role of vancomycin in an era of existing alternatives such as linezolid, daptomycin and tigecycline. Finally, compounds in early development are described, such as iclaprim, friulimicin, and retapamulin, among others. PMID:21694878

  14. Regulation of Apoptosis by Gram-Positive Bacteria

    PubMed Central

    Ulett, Glen C.; Adderson, Elisabeth E.

    2008-01-01

    Apoptosis, or programmed cell death (PCD), is an important physiological mechanism, through which the human immune system regulates homeostasis and responds to diverse forms of cellular damage. PCD may also be involved in immune counteraction to microbial infection. Over the past decade, the amount of research on bacteria-induced PCD has grown tremendously, and the implications of this mechanism on immunity are being elucidated. Some pathogenic bacteria actively trigger the suicide response in critical lineages of leukocytes that orchestrate both the innate and adaptive immune responses; other bacteria proactively prevent PCD to benefit their own survival and persistence. Currently, the microbial virulence factors, which represent the keys to unlocking the suicide response in host cells, are a primary focus of this field. In this review, we discuss these bacterial “apoptosis regulatory molecules” and the apoptotic events they either trigger or prevent, the host target cells of this regulatory activity, and the possible ramifications for immunity to infection. Gram-positive pathogens including Staphylococcus, Streptococcus, Bacillus, Listeria, and Clostridia species are discussed as important agents of human infection that modulate PCD pathways in eukaryotic cells. PMID:19081777

  15. Identification of Surprisingly Diverse Type IV Pili, across a Broad Range of Gram-Positive Bacteria

    E-print Network

    Plotkin, Joshua B.

    Identification of Surprisingly Diverse Type IV Pili, across a Broad Range of Gram-Positive Bacteria, Pennsylvania, United States of America Abstract Background: In Gram-negative bacteria, type IV pili (TFP) have apparent that Gram-positive bacteria also express type IV pili; however, little is known about

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

    Microsoft Academic Search

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

    1997-01-01

    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

  17. Diversity and abundance of Gram positive bacteria in a tidal flat ecosystem

    Microsoft Academic Search

    Heike Stevens; Thorsten Brinkhoff; Beate Rink; John Vollmers; Meinhard Simon

    2007-01-01

    Summary Gram positive bacteria recently have been identified as important components of freshwater ecosystems and are also present in marine environments. However, their quantitative significance and possible role in the latter systems is still little studied, in par- ticular in coastal regions. Therefore, we investigated the abundance and composition of Gram positive bacteria in the Wadden Sea, a tidal flat

  18. Purification Techniques of Bacteriocins from Lactic Acid Bacteria and Other Gram-Positive Bacteria

    Microsoft Academic Search

    Lucila Saavedra; Fernando Sesma

    2011-01-01

    \\u000a The search for new antimicrobial peptides produced by lactic acid ­bacteria and other Gram-positive microorganisms has become\\u000a an interesting field of research in the past decades. The fact that bacteriocins are active against numerous foodborne and\\u000a human pathogens, are produced by generally regarded as safe (GRAS) microorganisms, and are readily degraded by proteolytic\\u000a host systems makes them attractive candidates for

  19. Isolating "Unknown" Bacteria in the Introductory Microbiology Laboratory: A New Selective Medium for Gram-Positives.

    ERIC Educational Resources Information Center

    McKillip, John L.; Drake, MaryAnne

    1999-01-01

    Describes the development, preparation, and use of a medium that can select against a wide variety of Gram-negative bacteria while still allowing growth and differentiation of a wide range of Gram-positives. (WRM)

  20. Acquired inducible antimicrobial resistance in Gram-positive bacteria.

    PubMed

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

    2012-08-01

    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

  1. Multidrug resistance in hydrocarbon-tolerant Gram-positive and Gram-negative bacteria.

    PubMed

    Stancu, Mihaela Marilena; Grifoll, Magdalena

    2011-01-01

    New Gram-positive and Gram-negative bacteria were isolated from Poeni oily sludge, using enrichment procedures. The six Gram-positive strains belong to Bacillus, Lysinibacillus and Rhodococcus genera. The eight Gram-negative strains belong to Shewanella, Aeromonas, Pseudomonas and Klebsiella genera. Isolated bacterial strains were tolerant to saturated (i.e., n-hexane, n-heptane, n-decane, n-pentadecane, n-hexadecane, cyclohexane), monoaromatic (i.e., benzene, toluene, styrene, xylene isomers, ethylbenzene, propylbenzene) and polyaromatic (i.e., naphthalene, 2-methylnaphthalene, fluorene) hydrocarbons, and also resistant to different antimicrobial agents (i.e., ampicillin, kanamycin, rhodamine 6G, crystal violet, malachite green, sodium dodecyl sulfate). The presence of hydrophilic antibiotics like ampicillin or kanamycin in liquid LB-Mg medium has no effects on Gram-positive and Gram-negative bacteria resistance to toxic compounds. The results indicated that Gram-negative bacteria are less sensitive to toxic compounds than Gram-positive bacteria, except one bacteria belonging to Lysinibacillus genus. There were observed cellular and molecular modifications induced by ampicillin or kanamycin to isolated bacterial strains. Gram-negative bacteria possessed between two and four catabolic genes (alkB, alkM, alkB/alkB1, todC1, xylM, PAH dioxygenase, catechol 2,3-dioxygenase), compared with Gram-positive bacteria (except one bacteria belonging to Bacillus genus) which possessed one catabolic gene (alkB/alkB1). Transporter genes (HAE1, acrAB) were detected only in Gram-negative bacteria. PMID:21478643

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

    NASA Astrophysics Data System (ADS)

    Guo, Yanyan; Rogelj, Snezna; Zhang, Peng

    2010-02-01

    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.

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

    Microsoft Academic Search

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

    2001-01-01

    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

  4. Cell to cell communication by autoinducing peptides in gram-positive bacteria

    Microsoft Academic Search

    Mark H. J. Sturme; Michiel Kleerebezem; Jiro Nakayama; Antoon D. L. Akkermans; Elaine E. Vaughan; Willem M. de Vos

    2002-01-01

    While intercellular communication systems in Gram-negative bacteria are often based on homoserine lactones as signalling molecules,\\u000a it has been shown that autoinducing peptides are involved in intercellular communication in Gram-positive bacteria. Many of\\u000a these peptides are exported by dedicated systems, posttranslationally modified in various ways, and finally sensed by other\\u000a cells via membrane-located receptors that are part of two-component regulatory

  5. Impedimetric detection of pathogenic Gram-positive bacteria using an antimicrobial peptide from class IIa bacteriocins.

    PubMed

    Etayash, Hashem; Jiang, Keren; Thundat, Thomas; Kaur, Kamaljit

    2014-02-01

    Real-time, label-free detection of Gram-positive bacteria with high selectivity and sensitivity is demonstrated using an interdigitated impedimetric array functionalized with naturally produced antimicrobial peptide from class IIa bacteriocins. The antimicrobial peptide, leucocin A, was chemically synthesized and covalently immobilized on interdigitated gold microelectrodes via the interaction between the C-terminal carboxylic acid of the peptide and free amines of a preattached thiolated linker. Exposing the peptide sensor to various concentrations of Gram-positive bacteria generated reproducible impedance spectra that detected peptide-bacteria interactions at a concentration of 1 cell/?L. The peptide sensor also selectively detected Listeria monocytogenes from other Gram-positive strains at a concentration of 10(3) cfu mL(-1). The study highlights that short peptide ligands from bacteriocin class offer high selectivity in bacterial detection and can be used in developing a robust, portable biosensor device to efficiently detect pathogenic Gram-positive bacteria in food samples. PMID:24400685

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

    PubMed Central

    Marilena L?z?roaie, Mihaela

    2010-01-01

    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

  7. Volatile organic compound analysis by ion molecule reaction mass spectrometry for Gram-positive bacteria differentiation.

    PubMed

    Dolch, M E; Hornuss, C; Klocke, C; Praun, S; Villinger, J; Denzer, W; Schelling, G; Schubert, S

    2012-11-01

    Approximately 50 % of all clinically proven infections in critically ill patients are caused by Gram-positive bacteria. The timely and appropriate treatment of these infections is vital in order to avoid negative outcomes. Hence, fast and reliable methods are needed for the early detection and identification of microorganisms. Recently, direct mass spectrometry-based analysis of volatile organic compounds emitted by microorganisms has been employed to study Gram-negative bacteria. Here, we report a feasibility study of ion molecule reaction mass spectrometry (IMR-MS) for in vitro growth detection and species differentiation of selected Gram-positive bacteria that are frequently isolated in blood culture samples, namely, Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus, and Staphylococcus epidermidis. Ion molecule reaction mass spectrometry was used to analyze the headspace above cultures containing Gram-positive bacteria incubated at 37 °C starting with 10(2) colony-forming units (CFU)/ml. Measurements to determine the presence of volatile organic compounds were performed 4, 8, and 24 h after incubation, respectively. The detection of microbial growth was accomplished already after 8 h in cultures containing E. faecalis. After 24 h of incubation, characteristic mass spectra were obtained for all species. Processing these mass spectra by hierarchic clustering and principal component analysis (PCA) enabled us to differentiate between bacterial species. IMR-MS in conjunction with a cumulative end-point model provides the means for rapid growth detection and differentiation of Gram-positive bacteria on the species level, typically within an analysis time of less than 3 min per sample. PMID:22782437

  8. When Ribonucleases Come into Play in Pathogens: A Survey of Gram-Positive Bacteria

    PubMed Central

    Jester, Brian C.; Romby, Pascale; Lioliou, Efthimia

    2012-01-01

    It is widely acknowledged that RNA stability plays critical roles in bacterial adaptation and survival in different environments like those encountered when bacteria infect a host. Bacterial ribonucleases acting alone or in concert with regulatory RNAs or RNA binding proteins are the mediators of the regulatory outcome on RNA stability. We will give a current update of what is known about ribonucleases in the model Gram-positive organism Bacillus subtilis and will describe their established roles in virulence in several Gram-positive pathogenic bacteria that are imposing major health concerns worldwide. Implications on bacterial evolution through stabilization/transfer of genetic material (phage or plasmid DNA) as a result of ribonucleases' functions will be covered. The role of ribonucleases in emergence of antibiotic resistance and new concepts in drug design will additionally be discussed. PMID:22550495

  9. Small regulatory RNAs from low-GC Gram-positive bacteria

    PubMed Central

    Brantl, Sabine; Brückner, Reinhold

    2014-01-01

    Small regulatory RNAs (sRNAs) that act by base-pairing were first discovered in so-called accessory DNA elements—plasmids, phages, and transposons—where they control replication, maintenance, and transposition. Since 2001, a huge body of work has been performed to predict and identify sRNAs in a multitude of bacterial genomes. The majority of chromosome-encoded sRNAs have been investigated in E. coli and other Gram-negative bacteria. However, during the past five years an increasing number of sRNAs were found in Gram-positive bacteria. Here, we outline our current knowledge on chromosome-encoded sRNAs from low-GC Gram-positive species that act by base-pairing, i.e., an antisense mechanism. We will focus on sRNAs with known targets and defined regulatory mechanisms with special emphasis on Bacillus subtilis. PMID:24576839

  10. Comparative in vitro activity of levofloxacin and ofloxacin against Gram-positive bacteria

    Microsoft Academic Search

    George M. Eliopoulos; Christine B. Wennersten; Robert C. Moellering

    1996-01-01

    The in vitro activity of levofloxacin against 506 Gram-positive bacteria was compared with those of D(?)-ofloxacin, ofloxacin, ciprofloxacin, and sparfloxacin. Levofloxacin was generally twice as active as ofloxacin against these organisms (range, 0–3 twofold dilutions). Sparfloxacin appeared to have the greatest activity overall, but for several groups of organisms minimum inhibitory concentrations (MIC90s) of this com pound were within one

  11. Surface-conjugated antimicrobial peptide leucocin a displays high binding to pathogenic gram-positive bacteria.

    PubMed

    Etayash, Hashem; Norman, Lana; Thundat, Thomas; Stiles, Michael; Kaur, Kamaljit

    2014-01-22

    Leucocin A, a representative class IIa bacteriocin, is a ribosomally synthesized antimicrobial peptide (AMP) that displays potent activity against specific gram-positive bacteria. The antibacterial activity of such peptides is preceded by the binding event that can be utilized for studying specific peptide-bacteria interactions. In this study, 37-residue Leucocin A (LeuA) was synthesized using solid-phase peptide synthesis and covalently immobilized on gold substrates from either the N- or C-terminal. Both the peptide monolayers on gold substrates were incubated separately with five strains of gram-positive bacteria and displayed differential binding to different strains with highest binding to pathogenic Listeria monocytogenes . The C-terminally immobilized LeuA showed higher bacterial binding compared to the N-terminally attached LeuA. The full length immobilized LeuA (37-residue) was active as well as displayed higher bacterial binding (73 ± 6 bacteria/100 ?m(2)) compared to 24-residue inactive LeuA fragment (40 ± 8 bacteria/100 ?m(2)) from the C-terminal region. The high and specific bacterial binding ability of LeuA functionalized surfaces support the potential use of class IIa bacteriocins in antimicrobial peptide-based diagnostic platforms. PMID:24359454

  12. Sample preparation of Gram-positive bacteria for identification by matrix assisted laser desorption\\/ionization time-of-flight

    Microsoft Academic Search

    Sandra C Smole; Lisa A King; Peter E Leopold; Robert D Arbeit

    2002-01-01

    A new sample preparation method was developed for fresh, whole-cell Gram-positive bacteria to be analyzed by matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry (MALDI ToF MS). With fresh, whole-cell Gram-negative bacteria of the Enterobacteriaceae family, we had previously achieved spectra consisting of >50 peaks and mass ranges of 2–25 kDa. Because similar spectral quantity could not be achieved for Gram-positive bacteria,

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

    PubMed Central

    Mitchell, Gabriel J.; Wiesenfeld, Kurt; Nelson, Daniel C.; Weitz, Joshua S.

    2013-01-01

    Gram-positive bacteria can 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 analyse 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 of 15–24 nm 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 insights into the range of cell wall hole sizes compatible with bacterial homeostasis. PMID:23303219

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

    PubMed Central

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

    2004-01-01

    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

  15. Transport Capabilities of Eleven Gram-positive Bacteria: Comparative Genomic Analyses

    PubMed Central

    Lorca, Graciela L.; Barabote, Ravi D.; Zlotopolski, Vladimir; Tran, Can; Winnen, Brit; Hvorup, Rikki N.; Stonestrom, Aaron J.; Nguyen, Elizabeth; Huang, Li-Wen; Kim, David S.; Saier, Milton H.

    2007-01-01

    The genomes of eleven Gram-positive bacteria that are important for human health and the food industry, nine low G+C lactic acid bacteria and two high G+C Gram-positive organisms, were analyzed for their complement of genes encoding transport proteins. Thirteen to eighteen percent of their genes encode transport proteins, larger percentages than observed for most other bacteria. All of these bacteria possess channel proteins, some of which probably function to relieve osmotic stress. Amino acid uptake systems predominate over sugar and peptide cation symporters, and of the sugar uptake porters, those specific for oligosaccharides and glycosides often outnumber those for free sugars. About 10% of the total transport proteins are constituents of putative multidrug efflux pumps with Major Facilitator Superfamily (MFS)-type pumps (55%) being more prevalent than ATP-binding cassette (ABC)-type pumps (33%), which, however, usually greatly outnumber all other types. An exception to this generalization is Streptococcus thermophilus with 54% of its drug efflux pumps belonging to the ABC superfamily and 23% belonging each to the Multidrug/Oligosaccharide/Polysaccharide (MOP) superfamily and the MFS. These bacteria also display peptide efflux pumps that may function in intercellular signalling, and macromolecular efflux pumps, many of predictable specificities. Most of the bacteria analyzed have no pmf-coupled or transmembrane flow electron carriers. The one exception is Brevibacterium linens, which in addition to these carriers, also has transporters of several families not represented in the other ten bacteria examined. Comparisons with the genomes of organisms from other bacterial kingdoms revealed that lactic acid bacteria possess distinctive proportions of recognized transporter types (e.g., more porters specific for glycosides than reducing sugars). Some homologues of transporters identified had previously been identified only in Gram-negative bacteria or in eukaryotes. Our studies reveal unique characteristics of the lactic acid bacteria such as the universal presence of genes encoding mechanosensitive channels, competence systems and large numbers of sugar transporters of the phosphotransferase system. The analyses lead to important physiological predictions regarding the preferred signalling and metabolic activities of these industrially important bacteria. PMID:17490609

  16. Homologous Recombination in Low dC + dG Gram-Positive Bacteria

    Microsoft Academic Search

    Humberto Sanchez; Begoña Carrasco; Silvia Ayora; Juan C. Alonso

    Homologous recombination is a process involved in the maintenance of chromosome integrity,\\u000a in shaping the evolution of pathogens, in the resistance to antibiotic treatment, and profoundly affecting\\u000a evolution. In low dC + dG Gram-positive bacteria genetic recombination of a non-replicative\\u000a \\u000a homologous DNA, which enters into the cell via transduction or conjugation, proceeds mainly by the\\u000a double-strand break repair machinery, and this process

  17. Small things considered: the small accessory subunits of RNA polymerase in Gram-positive bacteria.

    PubMed

    Weiss, Andy; Shaw, Lindsey N

    2015-07-01

    The DNA-dependent RNA polymerase core enzyme in Gram-positive bacteria consists of seven subunits. Whilst four of them (?2??(')) are essential, three smaller subunits, ?, ? and ? (?9-21.5 kDa), are considered accessory. Both ? and ? have been viewed as integral components of RNAP for several decades; however, ? has only recently been described. Functionally these three small subunits carry out a variety of tasks, imparting important, supportive effects on the transcriptional process of Gram-positive bacteria. While ? is thought to have a wide range of roles, reaching from maintaining structural integrity of RNAP to ? factor recruitment, the only suggested function for ? thus far is in protecting cells from phage infection. The third subunit, ?, has been shown to have distinct influences in maintaining transcriptional specificity, and thus has a key role in cellular fitness. Collectively, all three accessory subunits, although dispensable under laboratory conditions, are often thought to be crucial for proper RNAP function. Herein we provide an overview of the available literature on each subunit, summarizing landmark findings that have deepened our understanding of these proteins and their function, and outline future challenges in understanding the role of these small subunits in the transcriptional process. PMID:25878038

  18. Isolation and identification of membrane vesicle-associated proteins in Gram-positive bacteria and mycobacteria

    PubMed Central

    Prados-Rosales, Rafael; Brown, Lisa; Casadevall, Arturo; Montalvo-Quirós, Sandra; Luque-Garcia, Jose L.

    2014-01-01

    Many intracellular bacterial pathogens naturally release membrane vesicles (MVs) under a variety of growth environments. For pathogenic bacteria there are strong evidences that released MVs are a delivery mechanism for the release of immunologically active molecules that contribute to virulence. Identification of membrane vesicle-associated proteins that can act as immunological modulators is crucial for opening up new horizons for understanding the pathogenesis of certain bacteria and for developing novel vaccines. In this protocol, we provide all the details for isolating MVs secreted by either mycobacteria or Gram-positive bacteria and for the subsequent identification of the protein content of the MVs by mass spectrometry. The protocol is adapted from Gram-negative bacteria and involves four main steps: (1) isolation of MVs from the culture media; (2) purification of MVs by density gradient ultrucentrifugation; (3) acetone precipitation of the MVs protein content and in-solution trypsin digestion and (4) mass spectrometry analysis of the generated peptides and protein identification. Our modifications are:•Growing Mycobacteria in a chemically defined media to reduce the number of unrelated bacterial components in the supernatant.•The use of an ultrafiltration system, which allows concentrating larger volumes.•In solution digestion of proteins followed by peptides purification by ziptip.

  19. The role of ? B in the stress response of Gram-positive bacteria – targets for food preservation and safety

    Microsoft Academic Search

    Willem van Schaik; Tjakko Abee

    2005-01-01

    The alternative sigma factor ¿B modulates the stress response of several Gram-positive bacteria, including Bacillus subtilis and the food-borne human pathogens Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus. In all these bacteria, ¿B is responsible for the transcription of genes that can confer stress resistance to the vegetative cell. Recent findings indicate that ¿B also plays an important role in

  20. Chitosan Augments Photodynamic Inactivation of Gram-Positive and Gram-Negative Bacteria?†

    PubMed Central

    Tsai, Tsuimin; Chien, Hsiung-Fei; Wang, Tze-Hsien; Huang, Ching-Tsan; Ker, Yaw-Bee; Chen, Chin-Tin

    2011-01-01

    Antimicrobial photodynamic inactivation (PDI) was shown to be a promising treatment modality for microbial infections. This study explores the effect of chitosan, a polycationic biopolymer, in increasing the PDI efficacy against Gram-positive bacteria, including Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, and methicillin-resistant S. aureus (MRSA), as well as the Gram-negative bacteria Pseudomonas aeruginosa and Acinetobacter baumannii. Chitosan at <0.1% was included in the antibacterial process either by coincubation with hematoporphyrin (Hp) and subjection to light exposure to induce the PDI effect or by addition after PDI and further incubation for 30 min. Under conditions in which Hp-PDI killed the microbe on a 2- to 4-log scale, treatment with chitosan at concentrations of as low as 0.025% for a further 30 min completely eradicated the bacteria (which were originally at ?108 CFU/ml). Similar results were also found with toluidine blue O (TBO)-mediated PDI in planktonic and biofilm cells. However, without PDI treatment, chitosan alone did not exert significant antimicrobial activity with 30 min of incubation, suggesting that the potentiated effect of chitosan worked after the bacterial damage induced by PDI. Further studies indicated that the potentiated PDI effect of chitosan was related to the level of PDI damage and the deacetylation level of the chitosan. These results indicate that the combination of PDI and chitosan is quite promising for eradicating microbial infections. PMID:21282440

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

    PubMed Central

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

    2014-01-01

    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

  2. Genetic features of circular bacteriocins produced by Gram-positive bacteria.

    PubMed

    Maqueda, Mercedes; Sánchez-Hidalgo, Marina; Fernández, Matilde; Montalbán-López, Manuel; Valdivia, Eva; Martínez-Bueno, Manuel

    2008-01-01

    This review highlights the main genetic features of circular bacteriocins, which require the co-ordinated expression of several genetic determinants. In general terms, it has been demonstrated that the expression of such structural genes must be combined with the activity of proteins involved in maturation (cleavage/circularization) and secretion outside the cell via different transporter systems, as well as multifaceted immunity mechanisms essential to ensuring the bacteria's self-protection against such strong inhibitors. Several circular antibacterial peptides produced by Gram-positive bacteria have been described to date, including enterocin AS-48, from Enterococcus faecalis S-48 (the first one characterized), gassericin A, from Lactobacillus gasseri LA39, and a similar one, reutericin 6, from Lactobacillus reuteri LA6, butyrivibriocin AR10, from the ruminal anaerobe Butyrivibrio fibrisolvens AR10, uberolysin, from Streptococcus uberis, circularin A, from Clostridium beijerinckii ATCC 25752, and subtilosin A, from Bacillus subtilis. We summarize here the progress made in the understanding of their principal genetic features over the last few years, during which the functional roles of circular proteins with wide biological activity have become clearer. PMID:18034824

  3. High-frequency conjugal plasmid transfer from gram-negative Escherichia coli to various gram-positive coryneform bacteria.

    PubMed Central

    Schäfer, A; Kalinowski, J; Simon, R; Seep-Feldhaus, A H; Pühler, A

    1990-01-01

    We report on the mobilization of shuttle plasmids from gram-negative Escherichia coli to gram-positive corynebacteria mediated by P-type transfer functions. Introduction of plasmids into corynebacteria was markedly enhanced after heat treatment of the recipient cells. High-frequency plasmid transfer was also observed when the restriction system of the recipient was mutated. On the basis of our data, we conclude that efficient DNA transfer from gram-negative to gram-positive bacteria, at least to coryneform bacteria, is conceivable in certain natural ecosystems. PMID:2106514

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

    PubMed Central

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

    2000-01-01

    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

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

    PubMed Central

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

    2015-01-01

    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

  6. Raman spectroscopy of xylitol uptake and metabolism in Gram-positive and Gram-negative bacteria.

    PubMed

    Palchaudhuri, Sunil; Rehse, Steven J; Hamasha, Khozima; Syed, Talha; Kurtovic, Eldar; Kurtovic, Emir; Stenger, James

    2011-01-01

    Visible-wavelength Raman spectroscopy was used to investigate the uptake and metabolism of the five-carbon sugar alcohol xylitol by Gram-positive viridans group streptococcus and the two extensively used strains of Gram-negative Escherichia coli, E. coli C and E. coli K-12. E. coli C, but not E. coli K-12, contains a complete xylitol operon, and the viridans group streptococcus contains an incomplete xylitol operon used to metabolize the xylitol. Raman spectra from xylitol-exposed viridans group streptococcus exhibited significant changes that persisted even in progeny grown from the xylitol-exposed mother cells in a xylitol-free medium for 24 h. This behavior was not observed in the E. coli K-12. In both viridans group streptococcus and the E. coli C derivative HF4714, the metabolic intermediates are stably formed to create an anomaly in bacterial normal survival. The uptake of xylitol by Gram-positive and Gram-negative pathogens occurs even in the presence of other high-calorie sugars, and its stable integration within the bacterial cell wall may discontinue bacterial multiplication. This could be a contributing factor for the known efficacy of xylitol when taken as a prophylactic measure to prevent or reduce occurrences of persistent infection. Specifically, these bacteria are causative agents for several important diseases of children such as pneumonia, otitis media, meningitis, and dental caries. If properly explored, such an inexpensive and harmless sugar-alcohol, alone or used in conjunction with fluoride, would pave the way to an alternative preventive therapy for these childhood diseases when the causative pathogens have become resistant to modern medicines such as antibiotics and vaccine immunotherapy. PMID:21037297

  7. In vitro assessment of Ag2O nanoparticles toxicity against Gram-positive and Gram-negative bacteria.

    PubMed

    Negi, Harshita; Rathinavelu Saravanan, Palaniyandi; Agarwal, Tithi; Ghulam Haider Zaidi, Mohd; Goel, Reeta

    2013-01-01

    In view of antibiotic resistance among pathogens, the present study is to address the toxicity of Ag2O nanoparticles against the Gram-positive and Gram-negative bacteria through in vitro assays. The preliminary screening by agar diffusion assay confirms the antibacterial activity of Ag2O nanoparticles against all the test bacteria. Comparative antibacterial activity of Ag2O nanoparticles and respective antibiotics reveals their broad range of activity and lower inhibitory dose against the used bacterial strains. Further, they can inhibit E. coli with an effective dose of 0.036 mg/ml within 1 h of exposure time as determined by luciferin based ATP assay. Moreover, the Ag2O nanoparticles exhibit higher antibacterial efficacy against Gram-negative bacteria than Gram-positive bacteria, as revealed by their MIC & MBC values. Therefore, Ag2O nanoparticles pave the way for a new generation of antibacterial agents against the emerging multidrug resistant pathogens. PMID:23518522

  8. Meso-substituted cationic porphyrins as efficient photosensitizers of gram-positive and gram-negative bacteria

    Microsoft Academic Search

    Michèle Merchat; Giulio Bertolini; Paolo Giacomini; Angeles Villaneuva; Giulio Jori

    1996-01-01

    Previous studies on the photosensitization of bacterial cells with different neutral or negatively charged porphyrins and phthalocyanines have demonstrated that, although Gram-positive bacteria are efficiently photoinactivated, Gram-negatrive bacteria become photosensitive only after modification of the permeability of their outer membrane.The results described in this paper show that two meso-substituted cationic porphyrins, namely tetra(4N-methyl-pyridyl) porphine tetraiodide and the tetra(4N,N,N,-trimethyl-anilinium) porphine, efficiently

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

    Microsoft Academic Search

    W. Kneifel; W. Leonhardt

    1992-01-01

    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

  10. Isolation and Characterization of Gram-Positive Piezophilic Bacteria from Deep Marine Subsurface Sediment

    NASA Astrophysics Data System (ADS)

    Runko, G. M.; Fang, J.; Kato, C.

    2014-12-01

    The marine deep biosphere remains as the least studied of all of Earth's habitats and is inadequately understood, but is extremely important to understand the impacts that microbes have on global biogeochemical cycles. Sediment samples were obtained during IODP Expedition 337 in the western Pacific Ocean, from 1,498 meters below the seafloor (mbsf; samples 6R3), 1,951-1,999 mbsf (19R1), and 2,406 mbsf (29R7). These samples were initially mixed with marine broth and cultivated under anaerobic conditions at pressure of 35 MPa (megapascal) and temperatures of 35° C, 45° C, and 55° C for 3 months on board the Chikyu. Single colonies were isolated via plating on marine broth. Then, six strains of bacteria were identified, 6R3-1, 6R3-15, 19R1-5, 29R7-12B, 29R7-12M, and 29R7-12S. The six strains were then examined for optimal growth temperature and pressure. These organisms are Gram-positive, spore-forming, facultative anaerobic piezophilic bacteria. Major fatty acids are anteiso-15:0, anteiso-17:0 and iso-15:0. Phylogenetic analysis of 16S rRNA gene sequences revealed that the isolates are closely related to Virgibacillus pantothenticus, Robinsoniella peoriensis, and Bacillus subtilis. Because of their abundance in the deep marine subsurface, these microorganisms likely play an important role in sustaining the deep microbial ecosystem and influencing biogeochemical cycles in the deep biosphere.

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

    PubMed

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

    2014-01-01

    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

  12. Linezolid in late-chronic prosthetic joint infection caused by gram-positive bacteria.

    PubMed

    Cobo, Javier; Lora-Tamayo, Jaime; Euba, Gorane; Jover-Sáenz, Alfredo; Palomino, Julián; del Toro, Ma Dolores; Rodríguez-Pardo, Dolors; Riera, Melchor; Ariza, Javier

    2013-05-01

    Linezolid may be an interesting alternative for prosthetic joint infection (PJI) due to its bioavailability and its antimicrobial spectrum. However, experience in this setting is scarce. The aim of the study was to assess linezolid's clinical and microbiological efficacy, and also its tolerance. This was a prospective, multicenter, open-label, non-comparative study of 25 patients with late-chronic PJI caused by Gram-positive bacteria managed with a two-step exchange procedure plus 6 weeks of linezolid. Twenty-two (88%) patients tolerated linezolid without major adverse effects, although a global decrease in the platelet count was observed. Three patients were withdrawn because of major toxicity, which reversed after linezolid stoppage. Among patients who completed treatment, 19 (86%) demonstrated clinical and microbiological cure. Two patients presented with clinical and microbiological failure, and one showed clinical cure and microbiological failure. In conclusion, linezolid showed good results in chronic PJI managed with a two-step exchange procedure. Tolerance seems acceptable, though close surveillance is required. PMID:23541692

  13. Quorum-sensing regulators in Gram-positive bacteria: 'cherchez le peptide '.

    PubMed

    Monnet, V; Gardan, R

    2015-07-01

    Gram-positive bacteria can regulate gene expression at the population level via a mechanism known as quorum sensing. Oligopeptides serve as the signaling molecules; they are secreted and then are either detected at the bacterial surface by two-component systems or reinternalized via an oligopeptide transport system. In the latter case, imported peptides interact with cognate regulators (phosphatases or transcriptional regulators) that modulate the expression of target genes. These regulators help control crucial functions such as virulence, persistence, conjugation and competence and have been reported in bacilli, enterococci and streptococci. They form the rapidly growing RRNPP group. In this issue of Molecular?Microbiology, Hoover et?al. (2015) highlight the group's importance: they have identified a new family of regulators, Tprs (Transcription factor regulated by a Phr peptide), which work with internalized Phr-like peptides. The mechanisms underlying the expression of the genes that encode these internalized peptides are poorly documented. However, Hoover et?al. (2015) have provided a new insight: an environmental molecule, glucose, can inhibit expression of the Phr-like peptide gene via catabolic repression. This previously undescribed regulatory pathway, controlling the production of a bacteriocin, might influence Streptococcus pneumonia's fitness in the nasopharynx, where galactose is present. PMID:25988215

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

    PubMed

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

    2013-01-01

    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

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

    PubMed Central

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

    2013-01-01

    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

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

    PubMed Central

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

    2013-01-01

    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

  17. A novel beta-defensin structure: a potential strategy of big defensin for overcoming resistance by Gram-positive bacteria.

    PubMed

    Kouno, Takahide; Fujitani, Naoki; Mizuguchi, Mineyuki; Osaki, Tsukasa; Nishimura, Shin-ichiro; Kawabata, Shun-ichiro; Aizawa, Tomoyasu; Demura, Makoto; Nitta, Katsutoshi; Kawano, Keiichi

    2008-10-01

    Big defensin is a 79-residue peptide derived from hemocytes of the Japanese horseshoe crab. It has antimicrobial activities against Gram-positive and -negative bacteria. The amino acid sequence of big defensin can be divided into an N-terminal hydrophobic half and a C-terminal cationic half. Interestingly, the trypsin cleaves big defensin into two fragments, the N-terminal and C-terminal fragments, which are responsible for antimicrobial activity against Gram-positive and -negative bacteria, respectively. To explore the antimicrobial mechanism of big defensin, we determined the solution structure of mature big defensin and performed a titration experiment with DPC micelles. Big defensin has a novel defensin structure; the C-terminal domain adopts a beta-defensin structure, and the N-terminal domain forms a unique globular conformation. It is noteworthy that the hydrophobic N-terminal domain undergoes a conformational change in micelle solution, while the C-terminal domain remains unchanged. Here, we propose that the N-terminal domain achieves its antimicrobial activity in a novel fashion and explain that big defensin has developed a strategy different from those of other beta-defensins to suppress the growth of Gram-positive bacteria. PMID:18785751

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

    Microsoft Academic Search

    David A. Fowle; Jeremy B. Fein

    1999-01-01

    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

  19. Changing epidemiology of infections in patients with neutropenia and cancer: emphasis on gram-positive and resistant bacteria.

    PubMed

    Zinner, S H

    1999-09-01

    Over the past 3 decades, considerable changes have occurred in the types of bacteria causing infection in febrile patients with neutropenia and cancer. Twenty years ago, gram-negative bacteria caused approximately 70% of bloodstream infections. As a probable consequence of long-dwelling intravascular devices, fluoroquinolone prophylaxis, and high-dose chemotherapy-induced mucositis, there has been a shift toward gram-positive coccal bacteremia. In most centers today, approximately 70% of bacteremic isolates are gram-positive cocci. Of potential concern is that antimicrobial-resistant gram-positive organisms are becoming increasingly frequent in patients with neutropenia. Fluoroquinolone-resistant Escherichia coli are being isolated from several cancer centers. Several "new" organisms, such as Stomatococcus mucilaginosus, Bacillus cereus, Leuconostoc species, Corynebacterium jeikeium, Rhodococcus species, Stenotrophomonas maltophilia, Moraxella catarrhalis, Burkholderia cepacia, and Bartonella species, now cause infections in these patients. Careful application of infection-control principles, judicious prophylaxis, appropriate evaluation of new antibiotics, and prompt effective therapy will maximize benefits for these patients. PMID:10530434

  20. The resemblance of clinical attributes between mastitic cows with no growth on bacterial milk cultures and those with gram-positive bacteria cultured.

    PubMed Central

    White, M E; Montgomery, M E

    1987-01-01

    The clinical attributes of 40 dairy cows which had mastitis but no growth of bacteria from the milk were analyzed and compared to the attributes in 102 cows with only gram-positive and 61 cows with only gram-negative bacteria cultured from the milk. Cows with no bacteria cultured from the milk did not differ significantly from cows with gram-positive bacteria cultured, but 9 of 12 attributes were significantly different between cows with no bacteria cultured and cows with gram-negative bacteria cultured. Discriminant analysis was used to classify cows as members of the gram-positive or gram-negative culture groups. The discriminant equation was then applied to the cows with no bacteria cultured, and 78% of cows with no bacteria cultured were classified as members of the gram-positive group. Most mastitis in cows with no bacteria grown from the milk was probably due to gram-positive bacteria. If antibiotic therapy is used in cows with persistent mastitis and a negative culture in the belief that the culture is a false negative, treatment with antibiotics effective only against gram-negative organisms would not be appropriate. PMID:3300920

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

    PubMed Central

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

    2012-01-01

    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

  2. Rapid Method for Detection of Gram-Positive and Negative Bacteria in Milk from Cows with Moderate or Severe Clinical Mastitis

    Microsoft Academic Search

    SIAMAK P. YAZDANKHAH; HENNING SØRUM; HANS JØRGEN S. LARSEN; GEIR GOGSTAD

    2001-01-01

    A rapid method for demonstration of gram-positive and gram-negative bacteria in milk is described. The technique is based on dilution of the sample in a medium, followed by filtration through a porous polysulfone membrane with a pore size retaining and concentrating bacteria from the sample. The bacteria concentrated on the surface of the membrane are stained with a cationic dye

  3. 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...

  4. 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

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

    2009-01-01

    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

  5. Comparison of the D-glutamate-adding enzymes from selected gram-positive and gram-negative bacteria.

    PubMed

    Walsh, A W; Falk, P J; Thanassi, J; Discotto, L; Pucci, M J; Ho, H T

    1999-09-01

    The biochemical properties of the D-glutamate-adding enzymes (MurD) from Escherichia coli, Haemophilus influenzae, Enterococcus faecalis, and Staphylococcus aureus were investigated to detect any differences in the activity of this enzyme between gram-positive and gram-negative bacteria. The genes (murD) that encode these enzymes were cloned into pMAL-c2 fusion vector and overexpressed as maltose-binding protein-MurD fusion proteins. Each fusion protein was purified to homogeneity by affinity to amylose resin. Proteolytic treatments of the fusion proteins with factor Xa regenerated the individual MurD proteins. It was found that these fusion proteins retain D-glutamate-adding activity and have Km and Vmax values similar to those of the regenerated MurDs, except for the H. influenzae enzyme. Substrate inhibition by UDP-N-acetylmuramyl-L-alanine, the acceptor substrate, was observed at concentrations greater than 15 and 30 microM for E. coli and H. influenzae MurD, respectively. Such substrate inhibition was not observed with the E. faecalis and S. aureus enzymes, up to a substrate concentration of 1 to 2 mM. In addition, the two MurDs of gram-negative origin were shown to require monocations such as NH4+ and/or K+, but not Na+, for optimal activity, while anions such as Cl- and SO4(2-) had no effect on the enzyme activities. The activities of the two MurDs of gram-positive origin, on the other hand, were not affected by any of the ions tested. All four enzymes required Mg2+ for the ligase activity and exhibited optimal activities around pH 8. These differences observed between the gram-positive and gram-negative MurDs indicated that the two gram-negative bacteria may apply a more stringent regulation of cell wall biosynthesis at the early stage of peptidoglycan biosynthesis pathway than do the two gram-positive bacteria. Therefore, the MurD-catalyzed reaction may constitute a fine-tuning step necessary for the gram-negative bacteria to optimally maintain its relatively thin yet essential cell wall structure during all stages of growth. PMID:10464212

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

    PubMed

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

    2014-01-01

    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

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

    PubMed Central

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

    2005-01-01

    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 A desaturase 1 gene (Scd1). flake homozygotes show reduced sebum production and are unable to synthesize the monounsaturated fatty acids (MUFA) palmitoleate (C16:1) and oleate (C18:1), both of which are bactericidal against gram-positive (but not gram-negative) organisms in vitro. However, intradermal MUFA administration to S. aureus-infected mice partially rescues the flake phenotype, which indicates that an additional component of the sebum may be required to improve bacterial clearance. In normal mice, transcription of Scd1—a gene with numerous NF-?B elements in its promoter—is strongly and specifically induced by TLR2 signaling. Similarly, the SCD1 gene is induced by TLR2 signaling in a human sebocyte cell line. These observations reveal the existence of a regulated, lipid-based antimicrobial effector pathway in mammals and suggest new approaches to the treatment or prevention of infections with gram-positive bacteria. PMID:16040962

  8. Acyl-sulfamates Target the Essential Glycerol-Phosphate Acyltransferase (PlsY) in Gram-Positive Bacteria

    PubMed Central

    Cherian, Philip; Yao, Jiangwei; Leonardi, Roberta; Maddox, Marcus M.; Luna, Vicki A.; Rock, Charles O.; Lee, Richard E.

    2012-01-01

    PlsY is the essential first step in membrane phospholipid synthesis of Gram-positive pathogens. PlsY catalyzes the transfer of the fatty acid from acyl-phosphate to the 1-position of glycerol-3-phosphate to form the first intermediate in membrane biogenesis. A series of non-metabolizable, acyl-sulfamate analogs of the acyl-phosphate PlsY substrate were prepared and evaluated as inhibitors of Staphylococcus aureus PlsY and for their Gram-positive antibacterial activities. From this series phenyl (8-phenyloctanoyl) sulfamate had the best overall profile, selectively inhibiting S. aureus phospholipid biosynthesis and causing the accumulation of both long-chain fatty acids and acyl-acyl carrier protein intermediates demonstrating that PlsY was the primary cellular target. Bacillus anthracis was unique in being more potently inhibited by long chain acyl-sulfamates than other bacterial species. However, it is shown that Bacillus anthracis PlsY is not more sensitive to the acyl-sulfamates than S. aureus PlsY. Metabolic profiling showed that B. anthracis growth inhibition by the acyl-sulfamates was not specific for lipid synthesis illustrating that the amphipathic acyl-sulfamates can also have off-target effects in Gram-positive bacteria. Nonetheless, this study further advances PlsY as a druggable target for the development of novel antibacterial therapeutics, through the discovery and validation of the probe compound phenyl (8-phenyloctanoyl) sulfamate as a S. aureus PlsY inhibitor. PMID:22795901

  9. Hyperspectral microscope imaging methods to classify gram-positive and gram-negative foodborne pathogenic bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An acousto-optic tunable filter-based hyperspectral microscope imaging method has potential for identification of foodborne pathogenic bacteria from microcolony rapidly with a single cell level. We have successfully developed the method to acquire quality hyperspectral microscopic images from variou...

  10. Classification of gram-positive and gram-negative foodborne pathogenic bacteria with hyperspectral microscope imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optical method with hyperspectral microscope imaging (HMI) has potential for identification of foodborne pathogenic bacteria from microcolonies rapidly with a cell level. A HMI system that provides both spatial and spectral information could be an effective tool for analyzing spectral characteristic...

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

    PubMed

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

    1991-02-01

    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

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

    PubMed Central

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

    2005-01-01

    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

  13. Mechanism of action of recombinant acc-royalisin from royal jelly of Asian honeybee against gram-positive bacteria.

    PubMed

    Shen, Lirong; Liu, Dandan; Li, Meilu; Jin, Feng; Din, Meihui; Parnell, Laurence D; Lai, Chao-Qiang

    2012-01-01

    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 Asian honeybee Apis cerana cerana, was expressed by fusing with glutathione S-transferase (GST) in Escherichia coli BL21, isolated and purified. The agar dilution assays with inhibition zone showed that RAcc-royalisin, similar to nisin, inhibits the growth of Gram-positive bacteria. The antibacterial activity of RAcc-royalisin was associated with its concentration, and was weakened by heat treatment ranging from 55°C to 85°C for 15 min. Both RAcc-royalisin and nisin exhibited the minimum inhibitory concentrations (MIC) of 62.5 µg/ml, 125 µg/ml, and 250 µg/ml against Gram-positive bacterial strains, Bacillus subtilis and Micrococcus flavus and Staphyloccocus aureus in the microplate assay, respectively. However, RAcc-royalisin did not show antimicrobial activity against tested Gram-negative bacterial and fungal strains. The antibacterial activity of RAcc-royalisin agrees well with the decrease in bacterial cell hydrophobicity, the leakage of 260-nm absorbing materials, and the observation by transmission electron microscopy, all indicating that RAcc-royalisin induced the disruption and dysfunction of cell walls and membranes. This is the first report detailing the antibacterial mechanism of royalisin against Gram-positive bacteria, and provides insight into the application of recombinant royalisin in food and pharmaceutical industries as an antimicrobial agent. PMID:23056609

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

    PubMed Central

    Navarre, William Wiley; Schneewind, Olaf

    1999-01-01

    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

  15. REPORT ANTIBACTERIAL ACTIVITY OF OREGANO (ORIGANUM VULGARE LINN.) AGAINST GRAM POSITIVE BACTERIA

    Microsoft Academic Search

    SABAHAT SAEED; PERWEEN TARIQ

    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,

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

    E-print Network

    Antibacterial Activity of Glutathione-Coated Silver Nanoparticles against Gram Positive and Gram ABSTRACT: In the present paper, we study the mechanism of antibacterial activity of glutathione (GSH on GSH Ag NPs grafted on glass allowed us to elucidate more precisely the antibacterial mechanism

  17. Synergy of fosfomycin with other antibiotics for Gram-positive and Gram-negative bacteria

    Microsoft Academic Search

    Antonia C. Kastoris; Petros I. Rafailidis; Evridiki K. Vouloumanou; Ioannis D. Gkegkes; Matthew E. Falagas

    2010-01-01

    Background  The alarming increase in drug resistance and decreased production of new antibiotics necessitate the evaluation of combinations\\u000a of existing antibiotics. Fosfomycin shows no cross-resistance to other antibiotic classes. Thus, its combination with other\\u000a antibiotics may potentially show synergy against resistant bacteria.\\u000a \\u000a \\u000a \\u000a \\u000a Objective  To evaluate the available published evidence regarding the in vitro synergistic activity of fosfomycin with other antibiotic\\u000a agents against

  18. Evaluation of the Verigene Gram-Positive Blood Culture Nucleic Acid Test for Rapid Detection of Bacteria and Resistance Determinants

    PubMed Central

    Wojewoda, Christina M.; Sercia, Linda; Navas, Maria; Tuohy, Marion; Wilson, Deborah; Hall, Geraldine S.; Procop, Gary W.

    2013-01-01

    Rapid identification of pathogens from blood cultures can decrease lengths of stay and improve patient outcomes. We evaluated the accuracy of the Verigene Gram-positive blood culture (BC-GP) nucleic acid test for investigational use only (Nanosphere, Inc., Northbrook, IL) for the identification of Gram-positive bacteria from blood cultures. The detection of resistance genes (mecA in Staphylococcus aureus and Staphylococcus epidermidis and vanA or vanB in Enterococcus faecium and Enterococcus faecalis) by the BC-GP assay also was assessed. A total of 186 positive blood cultures (in BacT/Alert FA bottles) with Gram-positive cocci observed with Gram staining were analyzed using the BC-GP assay. The BC-GP results were compared with the identification and susceptibility profiles obtained with routine methods in the clinical laboratory. Discordant results were arbitrated with additional biochemical, cefoxitin disk, and repeat BC-GP testing. The initial BC-GP organism identification was concordant with routine method results for 94.6% of the blood cultures. Only 40% of the Streptococcus pneumoniae identifications were correct. The detection of the mecA gene for 69 blood cultures with only S. aureus or S. epidermidis was concordant with susceptibility testing results. For 3 of 6 cultures with multiple Staphylococcus spp., mecA detection was reported but was correlated with oxacillin resistance in a species other than S. aureus or S. epidermidis. The detection of vanA agreed with susceptibility testing results for 45 of 46 cultures with E. faecalis or E. faecium. Comparison of the mean times to results for each organism group showed that BC-GP results were available 31 to 42 h earlier than phenotypic identifications and 41 to 50 h earlier than susceptibility results. PMID:23596240

  19. Invariant natural killer T cells recognize glycolipids from pathogenic Gram-positive bacteria.

    PubMed

    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

    2011-10-01

    Natural killer T cells (NKT cells) recognize glycolipid antigens presented by CD1d. These cells express an evolutionarily conserved, invariant T cell antigen receptor (TCR), but the forces that drive TCR conservation have remained uncertain. Here we show that NKT cells recognized 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 were required for activation and host protection. The glycolipid response was dependent on vaccenic acid, which is present in low concentrations in mammalian cells. Our results show how microbial lipids position the sugar for recognition by the invariant TCR and, most notably, extend the range of microbes recognized by this conserved TCR to several clinically important bacteria. PMID:21892173

  20. Anaerobic naphthalene degradation by Gram-positive, iron-reducing bacteria.

    PubMed

    Kleemann, Rita; Meckenstock, Rainer U

    2011-12-01

    An anaerobic naphthalene-degrading culture (N49) was enriched with ferric iron as electron acceptor. A closed electron balance indicated the total oxidation of naphthalene to CO(2). In all growing cultures, the concentration of the presumed central metabolite of naphthalene degradation, 2-naphthoic acid, increased concomitantly with growth. The first metabolite of anaerobic methylnaphthalene degradation, naphthyl-2-methyl-succinic acid, was not identified in culture supernatants, which does not support a methylation to methylnaphthalene as the initial activation reaction of naphthalene, but rather a carboxylation, as proposed for other naphthalene-degrading cultures. Substrate utilization tests revealed that the culture was able to grow on 1-methyl-naphthalene, 2-methyl-naphthalene, 1-naphthoic acid or 2-naphthoic acid, whereas it did not grow on 1-naphthol, 2-naphthol, anthracene, phenanthrene, indane and indene. Terminal restriction fragment length polymorphism and 16S rRNA gene sequence analyses revealed that the microbial community of the culture was dominated by one bacterial microorganism, which was closely related (99% 16S sequence similarity) to the major organism in the iron-reducing, benzene-degrading enrichment culture BF [ISME J (2007) 1: 643; Int J Syst Evol Microbiol (2010) 60: 686]. The phylogenetic classification supports a new candidate species and genus of Gram-positive spore-forming iron-reducers that can degrade non-substituted aromatic hydrocarbons. It furthermore indicates that Gram-positive microorganisms might also play an important role in anaerobic polycyclic aromatic hydrocarbon-degradation. PMID:22066721

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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.

  2. In vivo transfer of genetic information between gram-positive and gram-negative bacteria.

    PubMed Central

    Trieu-Cuot, P; Gerbaud, G; Lambert, T; Courvalin, P

    1985-01-01

    A 1427-bp DNA fragment containing the kanamycin resistance gene, aphA-3, of plasmid pIP1433 from Campylobacter coli was inserted into a shuttle vector. Full expression of aphA-3 was obtained in Bacillus subtilis and in Escherichia coli. This DNA fragment was sequenced in its entirety and the starting point for aphA-3 transcription in B. subtilis, C. coli and E. coli was determined by S1 nuclease mapping. The sequence of the promoter consists of the hexanucleotides TTGACA and TATAAT, with a spacing of 17 bp. The nucleotide sequence of the aphA-3 gene from C. coli and from the streptococcal plasmid pJH1 are identical whereas they differ by two substitutions and deletion of a codon from that cloned from the staphylococcal plasmid pSH2. These results indicate a recent extension of the resistant gene pool of Gram-positive cocci to Gram-negative bacilli. From an analysis of the DNA sequences surrounding the promoter region, we concluded that the DNA fragment containing the aphA-3 gene in plasmid pJH1 has evolved by deletions from a sequence similar to that found in plasmid pIP1433. Images Fig. 4. PMID:3937729

  3. Multistep Resistance Development Studies of Ceftaroline in Gram-Positive and -Negative Bacteria?

    PubMed Central

    Clark, Catherine; McGhee, Pamela; Appelbaum, Peter C.; Kosowska-Shick, Klaudia

    2011-01-01

    Ceftaroline, the active component of the prodrug ceftaroline fosamil, is a novel broad-spectrum cephalosporin with bactericidal activity against Gram-positive and -negative isolates. This study evaluated the potential for ceftaroline and comparator antibiotics to select for clones of Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, Moraxella catarrhalis, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecalis with elevated MICs. S. pneumoniae and S. pyogenes isolates in the present study were highly susceptible to ceftaroline (MIC range, 0.004 to 0.25 ?g/ml). No streptococcal strains yielded ceftaroline clones with increased MICs (defined as an increase in MIC of >4-fold) after 50 daily passages. Ceftaroline MICs for H. influenzae and M. catarrhalis were 0.06 to 2 ?g/ml for four strains and 8 ?g/ml for a ?-lactamase-positive, efflux-positive H. influenzae with a mutation in L22. One H. influenzae clone with an increased ceftaroline MIC (quinolone-resistant, ?-lactamase-positive) was recovered after 20 days. The ceftaroline MIC for this isolate increased 16-fold, from 0.06 to 1 ?g/ml. MICs for S. aureus ranged from 0.25 to 1 ?g/ml. No S. aureus isolates tested with ceftaroline had clones with increased MIC (>4-fold) after 50 passages. Two E. faecalis isolates tested had ceftaroline MICs increased from 1 to 8 ?g/ml after 38 days and from 4 to 32 ?g/ml after 41 days, respectively. The parental ceftaroline MIC for the one K. pneumoniae extended-spectrum ?-lactamase-negative isolate tested was 0.5 ?g/ml and did not change after 50 daily passages. PMID:21343467

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

    PubMed

    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

    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

  5. Antimicrobial photodynamic efficiency of novel cationic porphyrins towards periodontal Gram-positive and Gram-negative pathogenic bacteria.

    PubMed

    Prasanth, Chandra Sekhar; Karunakaran, Suneesh C; Paul, Albish K; Kussovski, Vesselin; Mantareva, Vanya; Ramaiah, Danaboyina; Selvaraj, Leslie; Angelov, Ivan; Avramov, Latchezar; Nandakumar, Krishnankutty; Subhash, Narayanan

    2014-01-01

    The Gram-negative Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum are major causative agents of aggressive periodontal disease. Due to increase in the number of antibiotic-resistant bacteria, antimicrobial Photodynamic therapy (aPDT) seems to be a plausible alternative. In this work, photosensitization was performed on Gram-positive and Gram-negative bacteria in pure culture using new-age cationic porphyrins, namely mesoimidazolium-substituted porphyrin derivative (ImP) and pyridinium-substituted porphyrin derivative (PyP). The photophysical properties of both the sensitizers including absorption, fluorescence emission, quantum yields of the triplet excited states and singlet oxygen generation efficiencies were evaluated in the context of aPDT application. The studied porphyrins exhibited high ability to accumulate into bacterial cells with complete penetration into early stage biofilms. As compared with ImP, PyP was found to be more effective for photoinactivation of bacterial strains associated with periodontitis, without any signs of dark toxicity, owing to its high photocytotoxicity. PMID:24164211

  6. Conserved Target for Group II Intron Insertion in Relaxase Genes of Conjugative Elements of Gram-Positive Bacteria

    PubMed Central

    Staddon, Jack H.; Bryan, Edward M.; Manias, Dawn A.; Dunny, Gary M.

    2004-01-01

    The lactococcal group II intron Ll.ltrB interrupts the ltrB relaxase gene within a region that encodes a conserved functional domain. Nucleotides essential for the homing of Ll.ltrB into an intronless version of ltrB are found exclusively at positions required to encode amino acids broadly conserved in a family of relaxase proteins of gram-positive bacteria. Two of these relaxase genes, pcfG from the enterococcal plasmid pCF10 and the ORF4 gene in the streptococcal conjugative transposon Tn5252, were shown to support Ll.ltrB insertion into the conserved motif at precisely the site predicted by sequence homology with ltrB. Insertion occurred through a mechanism indistinguishable from retrohoming. Splicing and retention of conjugative function was demonstrated for pCF10 derivatives containing intron insertions. Ll.ltrB targeting of a conserved motif of a conjugative element suggests a mechanism for group II intron dispersal among bacteria. Additional support for this mechanism comes from sequence analysis of the insertion sites of the E.c.I4 family of bacterial group II introns. PMID:15060042

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

    PubMed Central

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

    2015-01-01

    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

  8. In-vitro activity of RP 59500, a new semisynthetic streptogramin antibiotic, against gram-positive bacteria.

    PubMed

    Brumfitt, W; Hamilton-Miller, J M; Shah, S

    1992-07-01

    A study of the in-vitro activity of RP 59500, a semisynthetic derivative of pristinamycin, against a range of Gram-positive bacteria including erythromycin-resistant strains was undertaken. MICs were determined by plate dilution in IsoSensitest agar and MBCs by velvet pad replication. RP 59500 was found to have in-vitro activity almost identical to that of its parent compound, pristinamycin. Sixty methicillin-resistant Staphylococcus aureus (MRSA) and 60 methicillin-sensitive S. aureus (MSSA) were found to be sensitive to RP 59500, with MICs of 0.13-1 mg/L. All the MSSA and most MRSA showed an MBC less than 2 mg/L. Erythromycin-resistant S. aureus (62) were as sensitive to RP 59500 as were erythromycin-sensitive strains (58). RP 59500 was more active against MRSA than fusidate, vancomycin, amikacin, ciprofloxacin, imipenem or erythromycin. Forty strains of coagulase-negative staphylococci (11 were erythromycin-resistant) showed MICs of 0.25-1 mg/L, and RP 59500 was more active than methicillin, erythromycin, imipenem, cefotaxime or vancomycin. Sixty strains of streptococci (20 pneumococci and 40 of groups A, B, C, or G) and 20 enterococci were inhibited by 0.13-1 mg/L and 0.25-4 mg/L, respectively. Gram-positive bacilli (five each of diphtheroids, lactobacilli, Listeria monocytogenes and Bacillus spp., and 19 Clostridium spp.) were also sensitive, with MICs of between 0.06 and 4 mg/L. All 279 strains tested were judged to be sensitive to RP 59500, which was bactericidal and showed a small inoculum effect. The activity against MRSA, and against erythromycin-resistant strains of all species was particularly interesting. PMID:1399948

  9. In Vitro Activity of Tedizolid Against Gram-Positive Bacteria in Patients With Skin and Skin Structure Infections and Hospital-Acquired Pneumonia: A Korean Multicenter Study.

    PubMed

    Lee, Yangsoon; Hong, Sung Kuk; Choi, Sunghak; Im, Weonbin; Yong, Dongeun; Lee, Kyungwon

    2015-09-01

    We compared the activities of tedizolid to those of linezolid and other commonly used antimicrobial agents against gram-positive cocci recovered from patients with skin and skin structure infections (SSSIs) and hospital-acquired pneumonia (HAP) in Korean hospitals. Gram-positive isolates were collected from 356 patients with SSSIs and 144 patients with HAP at eight hospitals in Korea from 2011 to 2014. SSSIs included impetigo, cellulitis, erysipelas, furuncles, abscesses, and infected burns. Antimicrobial susceptibility was tested by using the CLSI agar dilution method. All of the gram-positive isolates were inhibited by ?1 ?g/mL tedizolid. The minimum inhibitory concentration [MIC]?? of tedizolid was 0.5 ?g/mL for methicillin-resistant Staphylococcus aureus, which was 4-fold lower than that of linezolid. Tedizolid may become a useful option for the treatment of SSSIs and HAP caused by gram-positive bacteria. PMID:26206690

  10. Triethyl-n-Hexylammonium Triethyl-n-Hexylboride: a New Antimicrobial Showing Activity Against Candida albicans and Gram-Positive Bacteria

    PubMed Central

    Rosenthal, K. S.; Storm, D. R.; Ford, W. T.

    1975-01-01

    The organic salt triethyl-n-hexylammonium triethyl-n-hexylboride (N2226B2226) has biostatic effects against two gram-positive bacteria, Bacillus subtilis and Micrococcus luteus, and the yeast Candida albicans. Escherichia coli and chicken embryo fibroblasts grown in tissue culture are more refractory to this compound. Images PMID:811160

  11. A light-up probe with aggregation-induced emission characteristics (AIE) for selective imaging, naked-eye detection and photodynamic killing of Gram-positive bacteria.

    PubMed

    Feng, Guangxue; Yuan, Youyong; Fang, Hu; Zhang, Ruoyu; Xing, Bengang; Zhang, Guanxin; Zhang, Deqing; Liu, Bin

    2015-07-21

    We report the design and synthesis of a red fluorescent AIE light-up probe for selective recognition, naked-eye detection, and image-guided photodynamic killing of Gram-positive bacteria, including vancomycin-resistant Enterococcus strains. PMID:26149530

  12. A Continuum of Anionic Charge: Structures and Functions of d-Alanyl-Teichoic Acids in Gram-Positive Bacteria

    PubMed Central

    Neuhaus, Francis C.; Baddiley, James

    2003-01-01

    Teichoic acids (TAs) are major wall and membrane components of most gram-positive bacteria. With few exceptions, they are polymers of glycerol-phosphate or ribitol-phosphate to which are attached glycosyl and d-alanyl ester residues. Wall TA is attached to peptidoglycan via a linkage unit, whereas lipoteichoic acid is attached to glycolipid intercalated in the membrane. Together with peptidoglycan, these polymers make up a polyanionic matrix that functions in (i) cation homeostasis; (ii) trafficking of ions, nutrients, proteins, and antibiotics; (iii) regulation of autolysins; and (iv) presentation of envelope proteins. The esterification of TAs with d-alanyl esters provides a means of modulating the net anionic charge, determining the cationic binding capacity, and displaying cations in the wall. This review addresses the structures and functions of d-alanyl-TAs, the d-alanylation system encoded by the dlt operon, and the roles of TAs in cell growth. The importance of dlt in the physiology of many organisms is illustrated by the variety of mutant phenotypes. In addition, advances in our understanding of d-alanyl ester function in virulence and host-mediated responses have been made possible through targeted mutagenesis of dlt. Studies of the mechanism of d-alanylation have identified two potential targets of antibacterial action and provided possible screening reactions for designing novel agents targeted to d-alanyl-TA synthesis. PMID:14665680

  13. Tumor necrosis factor alpha mediates lethal activity of killed gram-negative and gram-positive bacteria in D-galactosamine-treated mice.

    PubMed Central

    Freudenberg, M A; Galanos, C

    1991-01-01

    Treatment with D-galactosamine increases sensitivity of lipopolysaccharide (LPS)-responder mice to the lethal effects of LPS, while nonresponder mice remain resistant (M.A. Freudenberg, D. Keppler, and C. Galanos, Infect. Immun. 51:891-895, 1986). In the present study it is shown that, in contrast to LPS, killed gram-negative bacteria (Salmonella abortus equi and S. typhimurium) were highly toxic for D-galactosamine-treated LPS-responder (C57BL/10 ScSN and C3H/HeN) and -nonresponder (C57BL/10 ScCR and C3H/HeJ) mice, although to a higher extent in the former strains. Also, killed gram-positive bacteria (Staphylococcus aureus, Propionibacterium acnes, and Mycobacterium phlei) exhibited toxicity for D-galactosamine-treated mice, LPS-responder and -nonresponder mice being equally susceptible. Evidently, bacterial components other than LPS may exhibit lethal effects in sensitized animals. In all cases, the lethality of LPS and of bacteria was inhibited by anti-tumor necrosis factor alpha (TNF-alpha) serum. While LPS induced TNF-alpha in vitro only in macrophages from LPS-responder mice, gram-negative and gram-positive bacteria induced TNF-alpha also in macrophages from LPS-nonresponder mice. The data show that TNF-alpha is a common endogenous mediator of the lethal activity of gram-negative and gram-positive bacteria. PMID:2037372

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

    PubMed Central

    2014-01-01

    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

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

    Microsoft Academic Search

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

    2006-01-01

    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

  16. 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

    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

    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

  17. Stenotrophomonas maltophilia D457R Contains a Cluster of Genes from Gram-Positive Bacteria Involved in Antibiotic and Heavy Metal Resistance

    PubMed Central

    Alonso, Ana; Sanchez, Patricia; Martínez, José L.

    2000-01-01

    A cluster of genes involved in antibiotic and heavy metal resistance has been characterized from a clinical isolate of the gram-negative bacterium Stenotrophomonas maltophilia. These genes include a macrolide phosphotransferase (mphBM) and a cadmium efflux determinant (cadA), together with the gene cadC coding for its transcriptional regulator. The cadC cadA region is flanked by a truncated IS257 sequence and a region coding for a bin3 invertase. Despite their presence in a gram-negative bacterium, these genetic elements share a common gram-positive origin. The possible origin of these determinants as a remnant composite transposon as well as the role of gene transfer between gram-positive and gram-negative bacteria for the acquisition of antibiotic resistance determinants in chronic, mixed infections is discussed. PMID:10858330

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

    PubMed

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

    2013-10-15

    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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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.

  20. effect of fruit juices and pomace extracts on the growth of Gram-positive and Gram-negative bacteria

    Microsoft Academic Search

    Judit Krisch; László Galgóczy; Mónika Tölgyesi; Tamás Papp; Csaba Vágvölgyi

    Extracts and juices of cultivated and wild fruits belonging to the families Rosaceae, Grossulariaceae, Moraceae, Berberidaceae, Polygonaceae, Caprifoliaceae and Cornaceae were examined for their growth reducing activity on four bacteria (Bacillus subtilis, B. cereus var. my- coides, Escherichia coli and Serratia marcescens). In vitro antibacterial activities were evaluated by microdilution plate assays. Black currant (Ribes nigrum), cornelian cherry (Cornus mas)

  1. Novel ferulate esterase from Gram-positive lactic acid bacteria and analyses of the recombinant enzyme produced in E. coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a plate containing ethyl ferulate as sole carbon source, various bacteria cultures were screened for ferulate esterase (FAE). Among a dozen of species showing positive FAE, one Lactobacillus fermentum strain NRRL 1932 demonstrated the strongest activity. Using a published sequence of ferulate ...

  2. The potent antimicrobial properties of cell penetrating peptide-conjugated silver nanoparticles with excellent selectivity for Gram-positive bacteria over erythrocytes

    NASA Astrophysics Data System (ADS)

    Liu, Lihong; Yang, Jun; Xie, Jianping; Luo, Zhentao; Jiang, Jiang; Yang, Yi Yan; Liu, Shaomin

    2013-04-01

    Silver nanoparticles are of great interest for use as antimicrobial agents. Studies aimed at producing potent nano-silver biocides have focused on manipulation of particle size, shape, composition and surface charge. Here, we report the cell penetrating peptide catalyzed formation of antimicrobial silver nanoparticles in N,N-dimethylformamide. The novel nano-composite demonstrated a distinctly enhanced biocidal effect toward bacteria (Gram-positive Bacillus subtilis, Gram-negative Escherichia coli) and pathogenic yeast (Candida albicans), as compared to triangular and extremely small silver nanoparticles. In addition, a satisfactory biocompatibility was verified by a haemolysis test. Our results provide a paradigm in developing strategies that can maximize the silver nanoparticle application potentials while minimizing the toxic effects.Silver nanoparticles are of great interest for use as antimicrobial agents. Studies aimed at producing potent nano-silver biocides have focused on manipulation of particle size, shape, composition and surface charge. Here, we report the cell penetrating peptide catalyzed formation of antimicrobial silver nanoparticles in N,N-dimethylformamide. The novel nano-composite demonstrated a distinctly enhanced biocidal effect toward bacteria (Gram-positive Bacillus subtilis, Gram-negative Escherichia coli) and pathogenic yeast (Candida albicans), as compared to triangular and extremely small silver nanoparticles. In addition, a satisfactory biocompatibility was verified by a haemolysis test. Our results provide a paradigm in developing strategies that can maximize the silver nanoparticle application potentials while minimizing the toxic effects. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr34254a

  3. 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

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

    1989-04-01

    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.

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

    PubMed Central

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

    2006-01-01

    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 cell-surface proteins was identified, which is conserved in a subgroup of gram-positive bacteria. Each gene cluster generally has one copy of four new gene families called cscA, cscB, cscC and cscD. Clusters encoding these cell-surface proteins were found only in complete genomes of Lactobacillus plantarum, Lactobacillus sakei, Enterococcus faecalis, Listeria innocua, Listeria monocytogenes, Lactococcus lactis ssp lactis and Bacillus cereus and in incomplete genomes of L. lactis ssp cremoris, Lactobacillus casei, Enterococcus faecium, Pediococcus pentosaceus, Lactobacillius brevis, Oenococcus oeni, Leuconostoc mesenteroides, and Bacillus thuringiensis. These genes are neither present in the genomes of streptococci, staphylococci and clostridia, nor in the Lactobacillus acidophilus group, suggesting a niche-specific distribution, possibly relating to association with plants. All encoded proteins have a signal peptide for secretion by the Sec-dependent pathway, while some have cell-surface anchors, novel WxL domains, and putative domains for sugar binding and degradation. Transcriptome analysis in L. plantarum shows that the cscA-D genes are co-expressed, supporting their operon organization. Many gene clusters are significantly up-regulated in a glucose-grown, ccpA-mutant derivative of L. plantarum, suggesting catabolite control. This is supported by the presence of predicted CRE-sites upstream or inside the up-regulated cscA-D gene clusters. Conclusion We propose that the CscA, CscB, CscC and CscD proteins form cell-surface protein complexes and play a role in carbon source acquisition. Primary occurrence in plant-associated gram-positive bacteria suggests a possible role in degradation and utilization of plant oligo- or poly-saccharides. PMID:16723015

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

    PubMed

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

    2014-09-01

    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

  6. 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

    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

    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

  7. An overview of antimicrobial susceptibility patterns of gram-positive bacteria from National Antimicrobial Resistance Surveillance Thailand (NARST) program from 2000 to 2005.

    PubMed

    Mootsikapun, Piroon; Trakulsomboon, Suwanna; Sawanpanyalert, Pathom; Aswapokee, Nalinee; Suankratay, Chusana

    2009-08-01

    In this overview, the authors summarize the antimicrobial susceptibility patterns of important Gram-positive bacteria from the National Antimicrobial Resistance Surveillance Thailand (NARST) program between 2000 and 2005 as well as the clinical implications. This collaborative network program was funded by the World Health Organization, and involved 33 hospitals throughout Thailand. There are rising trends of drug-resistant S. pneumoniae (DRSP), ampicillin-resistant enterococci, but a constant occurrence of methicillin-resistant S. aureus (MRSA) was noted during this period. The rates of penicillin and erythromycin resistances of S. pneumoniae were constantly high, ranging from 42.5% to 47.7% and 24.6% to 31.1%, respectively, whereas the rates of cefotaxime resistance were quite low, ranging from 2.1% to 8.4%. The rates of multidrug-resistant (MDR) S. pneumoniae ranged from 14.8% to 34.3%. Of all S. aureus isolates, MRSA comprised 24% to 27%, and vancomycin resistance rates of these MRSA isolates ranged from 0.1% to 0.8%. The antimicrobial resistance rates of methicillin-susceptible S. aureus isolates were very low. The rates of ampicillin and high-level gentamicin resistances of E. faecium from 2000 to 2005 have been significantly increasing from 52% to 84.1%, and from 46.9% to 75%, respectively, but vancomycin resistance was stable at the rates between 0.4% and 1.9%. In conclusions, antimicrobial resistance rates of important Gram-positive bacteria have been increasing in Thailand. All local, national, and international surveillance data will help to set the strategic plan for control and treatment of these resistant organisms. Appropriate and accurate microbiological procedures regarding the collection and transportation of clinical specimens as well as the identification of these emerging resistant organisms are urgently needed, in collaboration with other concerned sectors. PMID:21294504

  8. [Studies on siderophore exchange properties between staphylococci and various species of gram-positive and gram-negative bacteria].

    PubMed

    Szarapi?ska-Kwaszewska, J; Mikucki, J

    1999-01-01

    The ability of iron utilizing by means of staphylococcal siderophores by bacteria belonging to genera: Acinetobacter, Corynebacterium, Curtobacterium, Clavibacter, Bacillus and Mycobacterium was investigated. The staphylococcal donor strains (18 species) used in these experiments were characterized by the ability to utilize siderophores produced by various strains belonging to aforenamed genera. The utilization of staphylococcal siderophores was studied on agar media in which minimally effective concentrations of ethylenediaminedi-ortho-hydroxyphenylacetic acid (EDDA) were used to inhibit indicator strains. Test colonies (staphylococcal) were applied to the surface of the media to determine whether the indicator organisms could obtain the required iron for growth by utilizing chelators from the test colony. The growth inhibition by EDDA of most strains from the Acinetobacter rods and from the coryneform-organisms (plant pathogen) genera, and strains from the species: B. subtilis, M. phlei, M. smegmatis, M. fortuitum was reversed by staphylococcal siderophores. None of the staphylococcal strains investigated, had the ability to exchange siderophores with strains from the species: C. pseudodiphtheriticum, Corynebacterium ANF group, B. megaterium, M. vaccae, M. chitae and M. parafortuitum. PMID:10803251

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

    PubMed

    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

    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

  10. Enhancement of Antibacterial Activity of Capped Silver Nanoparticles in Combination with Antibiotics, on Model Gram-Negative and Gram-Positive Bacteria

    PubMed Central

    Kora, Aruna Jyothi; Rastogi, Lori

    2013-01-01

    The nanoparticles used in this study were prepared from AgNO3 using NaBH4 in the presence of capping agents such as citrate, sodium dodecyl sulfate, and polyvinylpyrrolidone. The formed nanoparticles were characterized with UV-Vis, TEM, and XRD. The generation of silver nanoparticles was confirmed from the appearance of yellow colour and an absorption maximum between 399 and 404?nm. The produced nanoparticles were found to be spherical in shape and polydisperse. For citrate, SDS, and PVP capped nanoparticles, the average particle sizes were 38.3 ± 13.5, 19.3 ± 6.0, and 16.0 ± 4.8?nm, respectively. The crystallinity of the nanoparticles in FCC structure is confirmed from the SAED and XRD patterns. Also, the combined antibacterial activity of these differently capped nanoparticles with selected antibiotics (streptomycin, ampicillin, and tetracycline) was evaluated on model Gram-negative and Gram-positive bacteria, employing disc diffusion assay. The activity of the tested antibiotics was enhanced in combination with all the stabilized nanoparticles, against both the Gram classes of bacteria. The combined effects of silver nanoparticles and antibiotics were more prominent with PVP capped nanoparticles as compared to citrate and SDS capped ones. The results of this study demonstrate potential therapeutic applications of silver nanoparticles in combination with antibiotics. PMID:23970844

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

    PubMed

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

    2014-04-01

    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

  12. Lactococcus lactis TrxD represents a subgroup of thioredoxins prevalent in Gram-positive bacteria containing WCXDC active site motifs.

    PubMed

    Björnberg, Olof; Efler, Petr; Ebong, Epie Denis; Svensson, Birte; Hägglund, Per

    2014-12-15

    Three protein disulfide reductases of the thioredoxin superfamily from the industrially important Gram-positive Lactococcus lactis (LlTrxA, LlTrxD and LlNrdH) are compared to the "classical" thioredoxin from Escherichia coli (EcTrx1). LlTrxA resembles EcTrx1 with a WCGPC active site motif and other key residues conserved. By contrast, LlTrxD is more distantly related and contains a WCGDC motif. Bioinformatics analysis suggests that LlTrxD represents a subgroup of thioredoxins from Gram-positive bacteria. LlNrdH is a glutaredoxin-like electron donor for ribonucleotide reductase class Ib. Based on protein-protein equilibria LlTrxA (E°'=-259mV) and LlNrdH (E°'=-238mV) show approximately 10mV higher standard state redox potentials than the corresponding E. coli homologues, while E°' of LlTrxD is -243mV, more similar to glutaredoxin than "classical" thioredoxin. EcTrx1 and LlTrxA have high capacity to reduce insulin disulfides and their exposed active site thiol is alkylated at a similar rate at pH 7.0. LlTrxD on the other hand, is alkylated by iodoacetamide at almost 100 fold higher rate and shows no activity towards insulin disulfides. LlTrxA, LlTrxD and LlNrdH are all efficiently reduced by NADPH dependent thioredoxin reductase (TrxR) from L. lactis and good cross-reactivity towards E. coli TrxR was observed with LlTrxD as the notable exception. PMID:25255970

  13. Two recombinant peptides, SpStrongylocins 1 and 2, from Strongylocentrotus purpuratus, show antimicrobial activity against Gram-positive and Gram-negative bacteria.

    PubMed

    Li, Chun; Blencke, Hans-Matti; Smith, L Courtney; Karp, Matti T; Stensvåg, Klara

    2010-03-01

    The cysteine-rich strongylocins were the first antimicrobial peptides (AMPs) discovered from the sea urchin species, Strongylocentrotus droebachiensis. Homologous putative proteins (called SpStrongylocin) were found in the sister species, S. purpuratus. To demonstrate that they exhibit the same antibacterial activity as strongylocins, cDNAs encoding the 'mature' peptides (SpStrongylocins 1 and 2) were cloned into a direct expression system fusing a protease cleavage site and two purification tags to the recombinant peptide. Both recombinant fusion peptides were expressed in a soluble form in an Escherichia coli strain tolerant to toxic proteins. Enterokinase was used to remove the fusion tags and purified recombinant SpStrongylocins 1 and 2 showed antimicrobial activity against both Gram-negative and Gram-positive bacteria. The results of membrane integrity assays against cytoplasmic membranes of E. coli suggest that both recombinant SpStrongylocins 1 and 2 conduct their antibacterial activity by intracellular killing mechanisms because no increase in membrane permeability was detected. PMID:19852980

  14. 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

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

    2011-01-01

    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

  15. MiniUIB, a Novel Minitransposon-Based System for Stable Insertion of Foreign DNA into the Genomes of Gram-Negative and Gram-Positive Bacteria

    PubMed Central

    Christie-Oleza, Joseph Alexander; Brunet-Galmés, Isabel; Lalucat, Jorge; Nogales, Balbina

    2013-01-01

    Transposition of the insertion sequence (IS) ISPpu12 is actively induced after conjugative interaction. The transposase of this IS can act in trans on structures flanked by inverted repeats similar to those of the transposon. Based on that fact, an ISPpu12-based minitransposon, miniUIB, has been constructed in order to biotechnologically exploit the self-regulation of ISPpu12 and its increased activity after conjugative interaction. Mobilization of the miniUIB structure into the genome of Pseudomonas stutzeri AN10 after conjugative interaction was demonstrated. A single gene, i.e., the kanamycin resistance determinant, or large genetic structures of >12 kb, i.e., alkBFGHJKL and alkST operons of Pseudomonas putida TF4-1L (GPo1), have been easily integrated in P. stutzeri AN10 by an RP4-based delivery system. Therefore, the integration of the alk determinants by use of the miniUIB system has extended the biodegradation capabilities of this strain. Plasmid pJOC100, containing the transposase and regulator genes of ISPpu12 adjacent to the miniUIB structure, was constructed in order to extend the host range of this biotechnologically useful genetic tool to other model and real-world bacteria. The effectiveness of the system for random mutagenesis in a phylogenetic wide range of bacteria and for the insertion of novel functions has been demonstrated, even in successive steps. PMID:23275505

  16. Bacillus subtilis subsp. subtilis CBMDC3f with antimicrobial activity against Gram-positive foodborne pathogenic bacteria: UV-MALDI-TOF MS analysis of its bioactive compounds.

    PubMed

    Torres, M J; Petroselli, G; Daz, M; Erra-Balsells, R; Audisio, M C

    2015-06-01

    In this work a new Bacillus sp. strain, isolated from honey, was characterized phylogenetically. Its antibacterial activity against three relevant foodborne pathogenic bacteria was studied; the main bioactive metabolites were analyzed using ultraviolet matrix assisted laser desorption-ionization mass spectrometry (UV-MALDI MS). Bacillus CBMDC3f was phylogenetically characterized as Bacillus subtilis subsp. subtilis after rRNA analysis of the 16S subunit and the gyrA gene (access codes Genbank JX120508 and JX120516, respectively). Its antibacterial potential was evaluated against Listeria monocytogenes (9 strains), B. cereus (3 strains) and Staphylococcus aureus ATCC29213. Its cell suspension and cell-free supernatant (CFS) exerted significant anti-Listeria and anti-S. aureus activities, while the lipopeptides fraction (LF) also showed anti-B. cereus effect. The UV-MALDI-MS analysis revealed surfactin, iturin and fengycin in the CFS, whereas surfactin predominated in the LF. The CFS from CBMDC3f contained surfactin, iturin and fengycin with four, two and four homologues per family, respectively, whereas four surfactin, one iturin and one fengycin homologues were identified in the LF. For some surfactin homologues, their UV-MALDI-TOF/TOF (MS/MS; Laser Induced Decomposition method, LID) spectra were also obtained. Mass spectrometry analysis contributed with relevant information about the type of lipopeptides that Bacillus strains can synthesize. From our results, surfactin would be the main metabolite responsible for the antibacterial effect. PMID:25820813

  17. Significance of postgrowth processing of ZnO nanostructures on antibacterial activity against gram-positive and gram-negative bacteria

    PubMed Central

    Mehmood, Shahid; Rehman, Malik A; Ismail, Hammad; Mirza, Bushra; Bhatti, Arshad S

    2015-01-01

    In this work, we highlighted the effect of surface modifications of one-dimensional (1D) ZnO nanostructures (NSs) grown by the vapor–solid mechanism on their antibacterial activity. Two sets of ZnO NSs were modified separately – one set was modified by annealing in an Ar environment, and the second set was modified in O2 plasma. Annealing in Ar below 800°C resulted in a compressed lattice, which was due to removal of Zn interstitials and increased O vacancies. Annealing above 1,000°C caused the formation of a new prominent phase, Zn2SiO4. Plasma oxidation of the ZnO NSs caused an expansion in the lattice due to the removal of O vacancies and incorporation of excess O. Photoluminescence (PL) spectroscopy was employed for the quantification of defects associated with Zn and O in the as-grown and processed ZnO NS. Two distinct bands were observed, one in the ultraviolet (UV) region, due to interband transitions, and other in the visible region, due to defects associated with Zn and O. PL confirmed the surface modification of ZnO NS, as substantial decrease in intensities of visible band was observed. Antibacterial activity of the modified ZnO NSs demonstrated that the surface modifications by Ar annealing limited the antibacterial characteristics of ZnO NS against Staphylococcus aureus. However, ZnO NSs annealed at 1,000°C or higher showed a remarkable antibacterial activity against Escherichia coli. O2 plasma–treated NS showed appreciable antibacterial activity against both E. coli and S. aureus. The minimum inhibition concentration was determined to be 0.5 mg/mL and 1 mg/mL for Ar-annealed and plasma-oxidized ZnO NS, respectively. It was thus proved that the O content at the surface of the ZnO NS was crucial to tune the antibacterial activity against both selected gram-negative (E. coli) and gram-positive (S. aureus) bacterial species.

  18. Expression of the avian-specific toll-like receptor 15 in chicken heterophils is mediated by gram-negative and gram-positive bacteria, but not TLR agonists.

    PubMed

    Nerren, Jessica R; He, Haiqi; Genovese, Kenneth; Kogut, Michael H

    2010-07-01

    Toll-like receptors (TLRs) are a critical component of the innate immune response of mammalian and avian species. While most mammalian TLRs have been well characterized, the chicken-specific TLR15 has not been extensively studied. We recently demonstrated that TLR15 is differentially expressed between Salmonella-susceptible-and-resistant chickens, indicating a potential role in the innate immune response to infection with Salmonella. The aim of the present study was to gain better insight into the nature of the ligand for TLR15 by characterizing gene expression patterns of TLR15 by heterophils in response to numerous bacterial-derived TLR agonists LPS, flagellin, CpG oligodeoxynucleotides, lipotechoic acid (LTA), peptidoglycan (PGN), and Pam3CSK4 (PAM), stimulation with live Salmonella enterica serovar Enteritidis (SE-used as a positive control), chicken isolates of Escherichia coli (EC) and Enterococcus gallinarum (EG), the equine-specific pathogen Rhodococcus equi, and stimulation with heat-killed, and formalin-killed SE, EC, and EG. TLR15 expression increased significantly in response to stimulation with live, heat-killed and formalin-killed SE, EC, and EG, but was unaffected by stimulation with known TLR agonists and R. equi. Overall, these observations demonstrate that the individual TLR agonists are not the ligand for TLR15, and that TLR15 recognizes a unique, non-secreted, heat-stabile component of both Gram-negative and Gram-positive bacteria commonly found in and/or capable of causing disease in chickens. PMID:20303182

  19. Ultrastructure of bacteria and the proportion of Gram-negative bacteria in marine sediments

    Microsoft Academic Search

    D. J. W. Moriarty; A. C. Hayward

    1982-01-01

    Bacteria in sediments from the surface aerobic layer (0–1 cm) and a deeper anaerobic layer (20–21 cm) of a seagrass bed were examined in section by transmission electron microscopy. Bacteria with a Gram-negative ultrastructure made up 90% of bacteria in the surface layer, and Gram-positive bacteria comprised 10%. In the anaerobic zone, Gram-negative bacteria comprised 70% and Gram-positive bacteria 30%

  20. Neutrophil Extracellular Traps Kill Bacteria

    Microsoft Academic Search

    Volker Brinkmann; Ulrike Reichard; Christian Goosmann; Beatrix Fauler; Yvonne Uhlemann; David S. Weiss; Yvette Weinrauch; Arturo Zychlinsky

    2004-01-01

    Neutrophils engulf and kill bacteria when their antimicrobial granules fuse with the phagosome. Here, we describe that, upon activation, neutrophils release granule proteins and chromatin that together form extracellular fibers that bind Gram-positive and -negative bacteria. These neutrophil extracellular traps (NETs) degrade virulence factors and kill bacteria. NETs are abundant in vivo in experimental dysentery and spontaneous human appendicitis, two

  1. BOGUS BACTERIA...

    NSDL National Science Digital Library

    Mrs. Deaton

    2007-01-24

    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... ...

  2. RX-P873, a Novel Protein Synthesis Inhibitor, Accumulates in Human THP-1 Monocytes and Is Active against Intracellular Infections by Gram-Positive (Staphylococcus aureus) and Gram-Negative (Pseudomonas aeruginosa) Bacteria.

    PubMed

    Buyck, Julien M; Peyrusson, Frédéric; Tulkens, Paul M; Van Bambeke, Françoise

    2015-08-01

    The pyrrolocytosine RX-P873, a new broad-spectrum antibiotic in preclinical development, inhibits protein synthesis at the translation step. The aims of this work were to study RX-P873's ability to accumulate in eukaryotic cells, together with its activity against extracellular and intracellular forms of infection by Staphylococcus aureus and Pseudomonas aeruginosa, using a pharmacodynamic approach allowing the determination of maximal relative efficacies (Emax values) and bacteriostatic concentrations (Cs values) on the basis of Hill equations of the concentration-response curves. RX-P873's apparent concentration in human THP-1 monocytes was about 6-fold higher than the extracellular one. In broth, MICs ranged from 0.125 to 0.5 mg/liter (S. aureus) and 2 to 8 mg/liter (P. aeruginosa), with no significant shift in these values against strains resistant to currently used antibiotics being noted. In concentration-dependent experiments, the pharmacodynamic profile of RX-P873 was not influenced by the resistance phenotype of the strains. Emax values (expressed as the decrease in the number of CFU from that in the initial inoculum) against S. aureus and P. aeruginosa reached more than 4 log units and 5 log units in broth, respectively, and 0.7 log unit and 2.7 log units in infected THP-1 cells, respectively, after 24 h. Cs values remained close to the MIC in all cases, making RX-P873 more potent than antibiotics to which the strains were resistant (moxifloxacin, vancomycin, and daptomycin for S. aureus; ciprofloxacin and ceftazidime for P. aeruginosa). Kill curves in broth showed that RX-P873 was more rapidly bactericidal against P. aeruginosa than against S. aureus. Taken together, these data suggest that RX-P873 may constitute a useful alternative for infections involving intracellular bacteria, especially Gram-negative species. PMID:26014952

  3. Antibiotic resistance in Gram-positive cocci

    Microsoft Academic Search

    J Jeljaszewicz; G Mlynarczyk; A Mlynarczyk

    2000-01-01

    Gram-positive cocci still predominate as a cause of nosocomial- and community-acquired infections. These organisms frequently reveal a high natural, intrinsic resistance to antimicrobials. Additionally, these bacteria are able to acquire resistance to frequently used drugs rapidly through selective pressure of the environment and via the genetic evolution of bacteria. The wide application of antimicrobials in medical and veterinary practice, usage

  4. Ethanol production in Gram-positive microbes

    DOEpatents

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

    1996-01-01

    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.

  5. Ethanol production in Gram-positive microbes

    DOEpatents

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

    1999-06-29

    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.

  6. Ethanol production in gram-positive microbes

    DOEpatents

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

    1999-01-01

    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.

  7. QUORUM SENSING IN BACTERIA

    Microsoft Academic Search

    Melissa B. Miller; Bonnie L. Bassler

    2001-01-01

    ? 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

  8. Crystallography of Gram-Positive Bacterial Adhesins

    Microsoft Academic Search

    Vengadesan Krishnan; Sthanam V. L. Narayana

    \\u000a Both Gram-negative and Gram-positive pathogens display a multitude of proteins and protein assemblies (pili or fimbriae) on\\u000a their cell surfaces, which are often used for adherence and initiate colonization and pathogenesis. Adhesive proteins known\\u000a as MSCRAMMs (microbial surface components recognizing adhesive matrix molecules), anchored by a specific enzyme called sortase\\u000a in Gram-positive bacteria, target the host’s extracellular matrix proteins (ECM)

  9. 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.

  10. Spirochaetes Hyperthermophilic bacteriaCyanobacteriaLow-GC Gram-positives

    E-print Network

    Hillis, David

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

  11. Bacteria Transformation

    NSDL National Science Digital Library

    National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

    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.

  12. Investigating lipoprotein biogenesis and function in the model Gram-positive bacterium Streptomyces coelicolormmi_7261 943..957

    E-print Network

    Palmer, Tracy

    Investigating lipoprotein biogenesis and function in the model Gram-positive bacterium Streptomyces the lipid- modified cysteine at the N-terminus of the mature lipoprotein. In all Gram-positive bacteria of the cyto- plasmic membrane. Here we identify lipoproteins in the model Gram-positive bacterium Streptomyces

  13. Experimental fossilisation of the thermophilic Gram-positive bacterium Geobacillus SP7A: a long duration preservation study.

    E-print Network

    Paris-Sud XI, Université de

    Experimental fossilisation of the thermophilic Gram-positive bacterium Geobacillus SP7A: a long of fossilised microbes in recent and ancient rocks, we experimentally silicified a Gram-positive bacterium of Gram-positive bacteria was extremely rapid, thus allowing very good preservation of Geobacillus SP7A

  14. Methanotrophic bacteria.

    PubMed Central

    Hanson, R S; Hanson, T E

    1996-01-01

    Methane-utilizing bacteria (methanotrophs) are a diverse group of gram-negative bacteria that are related to other members of the Proteobacteria. These bacteria are classified into three groups based on the pathways used for assimilation of formaldehyde, the major source of cell carbon, and other physiological and morphological features. The type I and type X methanotrophs are found within the gamma subdivision of the Proteobacteria and employ the ribulose monophosphate pathway for formaldehyde assimilation, whereas type II methanotrophs, which employ the serine pathway for formaldehyde assimilation, form a coherent cluster within the beta subdivision of the Proteobacteria. Methanotrophic bacteria are ubiquitous. The growth of type II bacteria appears to be favored in environments that contain relatively high levels of methane, low levels of dissolved oxygen, and limiting concentrations of combined nitrogen and/or copper. Type I methanotrophs appear to be dominant in environments in which methane is limiting and combined nitrogen and copper levels are relatively high. These bacteria serve as biofilters for the oxidation of methane produced in anaerobic environments, and when oxygen is present in soils, atmospheric methane is oxidized. Their activities in nature are greatly influenced by agricultural practices and other human activities. Recent evidence indicates that naturally occurring, uncultured methanotrophs represent new genera. Methanotrophs that are capable of oxidizing methane at atmospheric levels exhibit methane oxidation kinetics different from those of methanotrophs available in pure cultures. A limited number of methanotrophs have the genetic capacity to synthesize a soluble methane monooxygenase which catalyzes the rapid oxidation of environmental pollutants including trichloroethylene. PMID:8801441

  15. Clinical microbiology of coryneform bacteria.

    PubMed Central

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

    1997-01-01

    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

  16. Magnetotactic Bacteria

    Microsoft Academic Search

    Richard Blakemore

    1975-01-01

    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.

  17. Bacteria TMDL Projects

    E-print Network

    Wythe, Kathy

    2007-01-01

    of TMDL projects for water bodies where swimming or wading may be unsafe or harvesting of oysters is limited or prohibited due to high concentrations of bacteria. ? Atascosa River: A TMDL Project for Bacteria ? Buffalo andWhite Oak Bayous: A TMDL... Creek: A TMDL Project for Bacteria ? Lower San Antonio River: A TMDL Project for Bacteria ? Upper San Antonio River: A TMDL Project for Bacteria ? Trinity River: A TMDL Project for Bacteria ? Upper Oyster Creek: A TMDL Project for Bacteria...

  18. Bacteria TMDL Projects 

    E-print Network

    Wythe, Kathy

    2007-01-01

    of TMDL projects for water bodies where swimming or wading may be unsafe or harvesting of oysters is limited or prohibited due to high concentrations of bacteria. ? Atascosa River: A TMDL Project for Bacteria ? Buffalo andWhite Oak Bayous: A TMDL... Creek: A TMDL Project for Bacteria ? Lower San Antonio River: A TMDL Project for Bacteria ? Upper San Antonio River: A TMDL Project for Bacteria ? Trinity River: A TMDL Project for Bacteria ? Upper Oyster Creek: A TMDL Project for Bacteria...

  19. Endophytic bacteria in Coffea arabica L.

    PubMed

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

    2005-01-01

    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

  20. Back To Bacteria.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    1997-01-01

    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)

  1. Structural and physiological characteristics of some sheathed bacteria

    Microsoft Academic Search

    Maria H. Deinema; S. Henstra; Eugenie von Elgg Werdmüller

    1977-01-01

    The fine structure and growth of two gram-negative and two gram-positive strains of sheathed bacteria, isolated from activated\\u000a sludge, have been studied. Their anatomy is quite different fromSphaerotilus natans. The cells are rectangular, tightly joined together, non-motile and enclosed by a sheath which is thin in the gram-negative\\u000a strains and rather electron-dense in the two larger gram-positive strains. The four

  2. 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.

  3. Cadmium uptake and resistance among selected bacteria

    SciTech Connect

    Burke, B.E.

    1987-01-01

    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.

  4. Gram-positive DsbE Proteins Function Differently from Gram-negative DsbE Homologs

    E-print Network

    Bardwell, James

    Gram-positive DsbE Proteins Function Differently from Gram-negative DsbE Homologs A STRUCTURE 07103 Mycobacterium tuberculosis, a Gram-positive bacte- rium, encodes a secreted Dsb-like protein oxidoreductase is an oxidant, unlike Gram-negative bacteria DsbE proteins, which have been shown to be weak

  5. Bacteria isolated from amoebae/bacteria consortium

    DOEpatents

    Tyndall, R.L.

    1995-05-30

    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.

  6. Bacteria isolated from amoebae/bacteria consortium

    DOEpatents

    Tyndall, Richard L. (Clinton, TN)

    1995-01-01

    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.

  7. Bacteria Inactivation During Lithotripsy

    NASA Astrophysics Data System (ADS)

    del Sol Quintero, María; Mora, Ulises; Gutiérrez, Jorge; Mues, Enrique; Castaño, Eduardo; Fernández, Francisco; Loske, Achim M.

    2006-09-01

    The influence of extracorporeal and intracorporeal lithotripsy on the viability of bacteria contained inside artificial kidney stones was investigated in vitro. Two different bacteria were exposed to the action of one extracorporeal shock wave generator and four intracorporeal lithotripters.

  8. 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.

  9. Phylogenetic analysis on the soil bacteria distributed in karst forest

    PubMed Central

    Zhou, JunPei; Huang, Ying; Mo, MingHe

    2009-01-01

    Phylogenetic composition of bacterial community in soil of a karst forest was analyzed by culture-independent molecular approach. The bacterial 16S rRNA gene was amplified directly from soil DNA and cloned to generate a library. After screening the clone library by RFLP, 16S rRNA genes of representative clones were sequenced and the bacterial community was analyzed phylogenetically. The 16S rRNA gene inserts of 190 clones randomly selected were analyzed by RFLP and generated 126 different RFLP types. After sequencing, 126 non-chimeric sequences were obtained, generating 113 phylotypes. Phylogenetic analysis revealed that the bacteria distributed in soil of the karst forest included the members assigning into Proteobacteria, Acidobacteria, Planctomycetes, Chloroflexi (Green nonsulfur bacteria), Bacteroidetes, Verrucomicrobia, Nitrospirae, Actinobacteria (High G+C Gram-positive bacteria), Firmicutes (Low G+C Gram-positive bacteria) and candidate divisions (including the SPAM and GN08). PMID:24031430

  10. Bacteria: More Than Pathogens

    NSDL National Science Digital Library

    Trudy Wassenaar (; )

    2002-07-01

    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.

  11. Bacteria: Friend or Foe?

    NSDL National Science Digital Library

    David Brock (Roland Park Public School; )

    2003-01-10

    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!

  12. The Drosophila immune system detects bacteria through specific peptidoglycan recognition

    Microsoft Academic Search

    François Leulier; Claudine Parquet; Sebastien Pili-Floury; Ji-Hwan Ryu; Martine Caroff; Won-Jae Lee; Dominique Mengin-Lecreulx; Bruno Lemaitre

    2003-01-01

    The Drosophila immune system discriminates between different classes of infectious microbes and responds with pathogen-specific defense reactions through selective activation of the Toll and the immune deficiency (Imd) signaling pathways. The Toll pathway mediates most defenses against Gram-positive bacteria and fungi, whereas the Imd pathway is required to resist infection by Gram-negative bacteria. The bacterial components recognized by these pathways

  13. Peptide signal molecules and bacteriocins in Gram-negative bacteria: a genome-wide in silico screening for peptides containing a double-glycine leader sequence and their cognate transporters

    Microsoft Academic Search

    G. Dirix; P. Monsieurs; B. Dombrecht; R. Daniels; K. Marchal; J. Vanderleyden; J. Michiels

    2004-01-01

    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 in Gram-negative bacteria of peptides and transporters that are involved in quorum sensing in Gram-positive bacteria. Many class II bacteriocins and inducing factors produced by lactic acid bacteria (LAB) and competence stimulating

  14. Bacteria Are Everywhere!

    NSDL National Science Digital Library

    AMPS GK-12 Program,

    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.

  15. Targeting intracellular bacteria with an extended cationic amphiphilic polyproline helix.

    PubMed

    Nepal, Manish; Thangamani, Shankar; Seleem, Mohamed N; Chmielewski, Jean

    2015-05-19

    An extended cationic and amphiphilic polyproline helix (CAPH) is described with a dual mode of action: effective cell penetration of human macrophages, and potent antimicrobial activity in vitro against both Gram-positive and negative pathogens, including Acinetobacter baumannii, Escherichia coli O157 and Bacillus anthracis. This dual action was successfully combined to clear pathogenic bacteria (Brucella and Salmonella) residing within macrophages. PMID:25925008

  16. Moderately halophilic gram-positive bacterial diversity in hypersaline environments.

    PubMed

    Ventosa, A; Márquez, M C; Garabito, M J; Arahal, D R

    1998-08-01

    Moderately halophilic bacteria are microorganisms that grow optimally in media containing 3%-15% (w/v) salt. They are represented by a heterogeneous group of microorganisms included in many different genera. Gram-negative moderately halophilic bacteria have been studied in more detail, but studies on gram-positive species are more scarce. Recent studies carried out by our research group on gram-positive moderate halophiles have permitted clarifying their taxonomic and phylogenetic position and describing new species. Thus, we have isolated six strains from ponds of salterns that show phenotypic and genotypic characteristics similar to those of Nesterenkonia halobia (formerly Micrococcus halobius), a moderately halophilic gram-positive coccus that was described on the basis of a single strain. Our data demonstrate quite clearly that they are members of this species and contribute to a better description of these moderately halophilic cocci. Similarly, a study of a large number of gram-positive moderately halophilic rods that were able to produce endospores led us to describe a new species, designated Bacillus salexigens. Further, isolates grouped in other three phenons, obtained by numerical taxonomy analysis and showing phenotypic features quite similar to those of this species, represent different genomovars, with very low DNA-DNA homology. Although they might represent additional new species, it will be necessary to determine new phenotypic features to differentiate them from previously described Bacillus species. We have also studied the viability of some old enrichments provided by B.E. Volcani, which were set up in 1936. We isolated 31 gram-positive motile endospore-forming rods that, according to their phenotypic characteristics, could represent a new species of the genus Bacillus. PMID:9783177

  17. 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.

  18. Bacteria and lignin degradation

    Microsoft Academic Search

    Jing Li; Hongli Yuan; Jinshui Yang

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material. It is degraded and\\u000a modified by bacteria in the natural world, and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.\\u000a Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling, erosion, and cavitation. With the advantages\\u000a of immense environmental

  19. High efficiency recombineering in lactic acid bacteria.

    PubMed

    van Pijkeren, Jan-Peter; Britton, Robert A

    2012-05-01

    The ability to efficiently generate targeted point mutations in the chromosome without the need for antibiotics, or other means of selection, is a powerful strategy for genome engineering. Although oligonucleotide-mediated recombineering (ssDNA recombineering) has been utilized in Escherichia coli for over a decade, the successful adaptation of ssDNA recombineering to gram-positive bacteria has not been reported. Here we describe the development and application of ssDNA recombineering in lactic acid bacteria. Mutations were incorporated in the chromosome of Lactobacillus reuteri and Lactococcus lactis without selection at frequencies ranging between 0.4% and 19%. Whole genome sequence analysis showed that ssDNA recombineering is specific and not hypermutagenic. To highlight the utility of ssDNA recombineering we reduced the intrinsic vancomymycin resistance of L. reuteri >100-fold. By creating a single amino acid change in the D-Ala-D-Ala ligase enzyme we reduced the minimum inhibitory concentration for vancomycin from >256 to 1.5?µg/ml, well below the clinically relevant minimum inhibitory concentration. Recombineering thus allows high efficiency mutagenesis in lactobacilli and lactococci, and may be used to further enhance beneficial properties and safety of strains used in medicine and industry. We expect that this work will serve as a blueprint for the adaptation of ssDNA recombineering to other gram-positive bacteria. PMID:22328729

  20. TSSWCB Bacteria-Related Projects

    E-print Network

    Wythe, Kathy

    2007-01-01

    of TMDL projects for water bodies where swimming or wading may be unsafe or harvesting of oysters is limited or prohibited due to high concentrations of bacteria. ? Atascosa River: A TMDL Project for Bacteria ? Buffalo andWhite Oak Bayous: A TMDL... Creek: A TMDL Project for Bacteria ? Lower San Antonio River: A TMDL Project for Bacteria ? Upper San Antonio River: A TMDL Project for Bacteria ? Trinity River: A TMDL Project for Bacteria ? Upper Oyster Creek: A TMDL Project for Bacteria...

  1. TSSWCB Bacteria-Related Projects 

    E-print Network

    Wythe, Kathy

    2007-01-01

    of TMDL projects for water bodies where swimming or wading may be unsafe or harvesting of oysters is limited or prohibited due to high concentrations of bacteria. ? Atascosa River: A TMDL Project for Bacteria ? Buffalo andWhite Oak Bayous: A TMDL... Creek: A TMDL Project for Bacteria ? Lower San Antonio River: A TMDL Project for Bacteria ? Upper San Antonio River: A TMDL Project for Bacteria ? Trinity River: A TMDL Project for Bacteria ? Upper Oyster Creek: A TMDL Project for Bacteria...

  2. Introduction to Bacteria

    NSDL National Science Digital Library

    DiscoverySchool.com

    2007-12-12

    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.

  3. 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...

  4. Studies on the mechanism of bacteria photosensitization by meso-substituted cationic porphyrins

    Microsoft Academic Search

    M. Merchat; J. D. Spikes; G. Bertoloni; G. Jori

    1996-01-01

    Cationic porphyrins have been shown to photoinduce the direct inactivation of Gram-positive (G+) and Gram-negative (G?) bacteria, thereby differing from anionic or neutral porphyrins which can photosensitize the G? bacteria only after permeabilization of their outer membrane. The present data show that the differences between these positively and negatively charged porphyrins are not related by a difference in the intrinsic

  5. Strong Synergy between a Eukaryotic Antimicrobial Peptide and Bacteriocins from Lactic Acid Bacteria

    Microsoft Academic Search

    Torben Luders; Gunn Alice Birkemo; Gunnar Fimland; Jon Nissen-Meyer; Ingolf F. Nes

    2003-01-01

    The antimicrobial effect obtained upon combining the prokaryotic antimicrobial peptides (AMPs; more commonly referred to as bacteriocins) pediocin PA-1, sakacin P, and curvacin A (all produced by lactic acid bacteria (LAB)) with the eukaryotic AMP pleurocidin (from fish) has been investigated. The three LAB AMPs alone were active against gram-positive Listeria ivanovii bacteria at nanomolar concentrations, whereas they were inactive

  6. Evaluation of a Fluorescent Lectin-Based Staining Technique for Some Acidophilic Mining Bacteria

    PubMed Central

    Fife, Dee Jay; Bruhn, Debby F.; Miller, Karen S.; Stoner, Daphne L.

    2000-01-01

    A fluorescence-labeled wheat germ agglutinin staining technique (R. K. Sizemore et al., Appl. Environ. Microbiol. 56:2245–2247, 1990) 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. PMID:10788401

  7. Invariant natural killer T cells recognize glycolipids from pathogenic Gram-positive bacteria

    Microsoft Academic Search

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

    2011-01-01

    Natural killer T cells (NKT cells) recognize glycolipid antigens presented by CD1d. These cells express an evolutionarily conserved, invariant T cell antigen receptor (TCR), but the forces that drive TCR conservation have remained uncertain. Here we show that NKT cells recognized diacylglycerol-containing glycolipids from Streptococcus pneumoniae, the leading cause of community-acquired pneumonia, and group B Streptococcus, which causes neonatal sepsis

  8. Functional Analysis of Alkane Hydroxylases from Gram-Negative and Gram-Positive Bacteria

    PubMed Central

    Smits, Theo H. M.; Balada, Stefanie B.; Witholt, Bernard; van Beilen, Jan B.

    2002-01-01

    We have cloned homologs of the Pseudomonas putida GPo1 alkane hydroxylase from Pseudomonas aeruginosa PAO1, Pseudomonas fluorescens CHA0, Alcanivorax borkumensis AP1, Mycobacterium tuberculosis H37Rv, and Prauserella rugosa NRRL B-2295. Sequence comparisons show that the level of protein sequence identity between the homologs is as low as 35%, and that the Pseudomonas alkane hydroxylases are as distantly related to each other as to the remaining alkane hydroxylases. Based on the observation that rubredoxin, an electron transfer component of the GPo1 alkane hydroxylase system, can be replaced by rubredoxins from other alkane hydroxylase systems, we have developed three recombinant host strains for the functional analysis of the novel alkane hydroxylase genes. Two hosts, Escherichia coli GEc137 and P. putida GPo12, were equipped with pGEc47?B, which encodes all proteins necessary for growth on medium-chain-length alkanes (C6 to C12), except a functional alkane hydroxylase. The third host was an alkB knockout derivative of P. fluorescens CHA0, which is no longer able to grow on C12 to C16 alkanes. All alkane hydroxylase homologs, except the Acinetobacter sp. ADP1 AlkM, allowed at least one of the three hosts to grow on n-alkanes. PMID:11872725

  9. An antimicrobial modified silicone peritoneal catheter with activity against both Gram positive and Gram negative bacteria

    Microsoft Academic Search

    Roger Bayston; Leanne E. Fisher; Klaus Weber

    2009-01-01

    Peritonitis, exit site and tunnel infections are serious complications of peritoneal dialysis (CAPD), which may lead to catheter loss, despite measures taken to reduce the infection rate. Catheters coated with antimicrobials have shown only short-term activity. We have developed a process for conferring broad-spectrum, long-duration antimicrobial activity on CAPD catheters while reducing the risk of resistance. Catheters were processed using

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

    E-print Network

    Gent, Universiteit

    In vitro conjugal transfer of tetracycline resistance from Lactobacillus isolates to other Gram June 2003 First published online 9 July 2003 Abstract The ability of 14 Lactobacillus strains, isolated was examined using filter mating experiments. Seven out of 14 tetracycline-resistant Lactobacillus isolates

  11. Horizontal spread of mer operons among Gram-positive bacteria in natural environments

    Microsoft Academic Search

    E. S. Bogdanova; I. A. Bass; L. S. Minakhin; M. A. Petrova; S. Z. Mindlin; A. A. Volodin; E. S. Kalyaeva; J. M. Tiedje; J. L. Hobman; N. L. Brown; V. G. Nikiforov

    1998-01-01

    Horizontal dissemination of the genes responsible for resistance to toxic pollutants may play a key role in the adaptation of bacterial populations to environmental contaminants. However, the frequency and extent of gene dissemination in natural environments is not known. A natural horizontal spread of two distinct mercury resistance (mer) operon variants, which occurred amongst diverse Bacillus and related species over

  12. Antibacterial Action of Structurally Diverse Cationic Peptides on Gram-Positive Bacteria

    Microsoft Academic Search

    CAROL L. FRIEDRICH; DIANNE MOYLES; TERRY J. BEVERIDGE; ROBERT E. W. HANCOCK

    2000-01-01

    Antimicrobial cationic peptides are ubiquitous in nature and are thought to be a component of the first line of defense against infectious agents. It is widely believed that the killing mechanism of these peptides on bac- teria involves an interaction with the cytoplasmic membrane. Cationic peptides from different structural classes were used in experiments with Staphylococcus aureus and other medically

  13. THE MITOCHONDRIA OF BACTERIA

    Microsoft Academic Search

    STUART MUDD

    1953-01-01

    Recent evidence from the biochemical, the genetic and the morphologic study of bacteria, in that chronological order, has indicated essential similarities of the bacterial cell to the cells of higher organisms. Recognition in bacteria of a large category of cytoplasmic granules as possessing characteristics which strongly sug- gest that they are the functional equivalents of the mitochondria of anirnaE and

  14. Bacteria turn tiny gears

    SciTech Connect

    None

    2009-01-01

    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

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

    PubMed

    Hegde, Sharath S; Janc, James W

    2014-12-01

    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

  16. Cultivation Media for Bacteria

    NSDL National Science Digital Library

    American Society For Microbiology

    2009-12-08

    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.

  17. Bleach vs. Bacteria

    MedlinePLUS

    ... the University of Michigan. In a series of experiments, her team showed that hypochlorous acid causes bacterial ... produced by almost all organisms, from bacteria to humans, may be one of the oldest molecular chaperones ...

  18. Bacteria in shear flow

    E-print Network

    Marcos, Ph.D. Massachusetts Institute of Technology

    2011-01-01

    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 ...

  19. How honey kills bacteria

    Microsoft Academic Search

    P. H. S. Kwakman; A. A. te Velde; L. de Boer; D. Speijer; C. M. J. E. Vandenbroucke-Grauls; S. A. J. Zaat

    2010-01-01

    With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria tested, including Bacillus subtilis, methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamase producing Escherichia coli, ciprofloxacin-resistant Pseudomonas aeruginosa, and vancomycin-resistant Enterococcus faecium, were

  20. Ecophysiology of Magnetotactic Bacteria

    Microsoft Academic Search

    Dennis A. Bazylinski; Timothy Williams

    Magnetotactic bacteria are a physiologically diverse group of prokaryotes whose main common features\\u000a are the biomineralization of magnetosomes and magnetotaxis, the passive alignment and active motility along\\u000a geomagnetic field lines. Magnetotactic bacteria exist in their highest numbers at or near the oxic–anoxic\\u000a interfaces (OAI) of chemically stratified aquatic habitats that contain inverse concentration gradients\\u000a of oxidants and reductants. Few species are

  1. Lipopolysaccharides in diazotrophic bacteria

    PubMed Central

    Serrato, Rodrigo V.

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure. PMID:25232535

  2. PVC biodeterioration and DEHP leaching by DEHP-degrading bacteria

    PubMed Central

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

    2012-01-01

    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

  3. Metabolic engineering of bacteria for ethanol production

    SciTech Connect

    Ingram, L.O.; Gomez, P.F.; Lai, X.; Moniruzzaman, M.; Wood, B.E.; Yomano, L.P.; York, S.W. [Univ. of Florida, Gainesville, FL (United States). Dept. of Microbiology and Cell Science] [Univ. of Florida, Gainesville, FL (United States). Dept. of Microbiology and Cell Science

    1998-04-20

    Technologies are available which will allow the conversion of lignocellulose into fuel ethanol using genetically engineered bacteria. Assembling these into a cost-effective process remains a challenge. The authors` work has focused primarily on the genetic engineering of enteric bacteria using a portable ethanol production pathway. Genes encoding Zymomonas mobilis pyruvate decarboxylase and alcohol dehydrogenase have been integrated into the chromosome of Escherichia coli B to produce strain KO11 for the fermentation of hemicellulose-derived syrups. This organism can efficiently ferment all hexose and pentose sugars present in the polymers of hemicellulose. Klebsiella oxytoca M5A1 has been genetically engineered in a similar manner to produce strain P2 for ethanol production from cellulose. This organism has the native ability to ferment cellobiose and cellotriose, eliminating the need for one class of cellulase enzymes. The optimal pH for cellulose fermentation with this organism is near that of fungal cellulases. The general approach for the genetic engineering of new biocatalysts has been most successful with enteric bacteria thus far. However, this approach may also prove useful with gram-positive bacteria which have other important traits for lignocellulose conversion. Many opportunities remain for further improvements in the biomass to ethanol processes.

  4. Endocarditis Due to Rare and Fastidious Bacteria

    PubMed Central

    Brouqui, P.; Raoult, D.

    2001-01-01

    The etiologic diagnosis of infective endocarditis is easily made in the presence of continuous bacteremia with gram-positive cocci. However, the blood culture may contain a bacterium rarely associated with endocarditis, such as Lactobacillus spp., Klebsiella spp., or nontoxigenic Corynebacterium, Salmonella, Gemella, Campylobacter, Aeromonas, Yersinia, Nocardia, Pasteurella, Listeria, or Erysipelothrix spp., that requires further investigation to establish the relationship with endocarditis, or the blood culture may be uninformative despite a supportive clinical evaluation. In the latter case, the etiologic agents are either fastidious extracellular or intracellular bacteria. Fastidious extracellular bacteria such as Abiotrophia, HACEK group bacteria, Clostridium, Brucella, Legionella, Mycobacterium, and Bartonella spp. need supplemented media, prolonged incubation time, and special culture conditions. Intracellular bacteria such as Coxiella burnetii cannot be isolated routinely. The two most prevalent etiologic agents of culture-negative endocarditis are C. burnetti and Bartonella spp. Their diagnosis is usually carried out serologically. A systemic pathologic examination of excised heart valves including periodic acid-Schiff (PAS) staining and molecular methods has allowed the identification of Whipple's bacillus endocarditis. Pathologic examination of the valve using special staining, such as Warthin-Starry, Gimenez, and PAS, and broad-spectrum PCR should be performed systematically when no etiologic diagnosis is evident through routine laboratory evaluation. PMID:11148009

  5. The fecal bacteria

    USGS Publications Warehouse

    Sadowsky, Michael J., (Edited By); Whitman, Richard L.

    2011-01-01

    The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

  6. Characterization of bacteria from a swine manure digester

    SciTech Connect

    Iannotti, E.L. (Univ. of Missouri, Columbia); Fischer, J.R.; Sievers, D.M.

    1982-01-01

    One-hundred thirty bacteria isolated from a swine manure digester were predominately gram-positive anaerobes which were tentatively classified into the following genera: Peptostreptococcus, Eubacterium, Bacteroides, Lactobacillus, Peptococcus, Clostridiu, and Streptococcus plus two unidentified groups. The major fermentation products formed by these organisms included acetate, propionate, succinate, lactate, and ethanol, singly or in various combinations. Acetate was the sole end product of several groups. Few of the isolates (14%) reduced the pH below 6.0. The predominate bacteria appear to differ from the predominate organisms isolated from other anaerobic ecosystems.

  7. Biofilm bacteria: formation and comparative susceptibility to antibiotics

    PubMed Central

    Olson, Merle E.; Ceri, Howard; Morck, Douglas W.; Buret, Andre G.; Read, Ronald R.

    2002-01-01

    The Calgary Biofilm Device (CBD) was used to form bacterial biofilms of selected veterinary gram-negative and gram-positive pathogenic bacteria from cattle, sheep, pigs, chicken, and turkeys. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) of ampicillin, ceftiofur, cloxacillin, oxytetracycline, penicillin G, streptomycin, tetracycline, enrofloxacin, erythromycin, gentamicin, tilmicosin, and trimethoprim-sulfadoxine for gram-positive and -negative bacteria were determined. Bacterial biofilms were readily formed on the CBD under selected conditions. The biofilms consisted of microcolonies encased in extracellular polysaccharide material. Biofilms composed of Arcanobacterium (Actinomyces) pyogenes, Staphylococcus aureus, Staphylococcus hyicus, Streptococcus agalactiae, Corynebacterium renale, or Corynebacterium pseudotuberculosis were not killed by the antibiotics tested but as planktonic bacteria they were sensitive at low concentrations. Biofilm and planktonic Streptococcus dysgalactiae and Streptococcus suis were sensitive to penicillin, ceftiofur, cloxacillin, ampicillin, and oxytetracycline. Planktonic Escherichia coli were sensitive to enrofloxacin, gentamicin, oxytetracycline and trimethoprim/ sulfadoxine. Enrofloxacin and gentamicin were the most effective antibiotics against E. coli growing as a biofilm. Salmonella spp. and Pseudomonas aeruginosa isolates growing as planktonic populations were sensitive to enrofloxacin, gentamicin, ampicillin, oxytetracycline, and trimethoprim/sulfadoxine, but as a biofilm, these bacteria were only sensitive to enrofloxacin. Planktonic and biofilm Pasteurella multocida and Mannheimia haemolytica had similar antibiotic sensitivity profiles and were sensitive to most of the antibiotics tested. The CBD provides a valuable new technology that can be used to select antibiotics that are able to kill bacteria growing as biofilms. PMID:11989739

  8. Biofilm bacteria: formation and comparative susceptibility to antibiotics.

    PubMed

    Olson, Merle E; Ceri, Howard; Morck, Douglas W; Buret, Andre G; Read, Ronald R

    2002-04-01

    The Calgary Biofilm Device (CBD) was used to form bacterial biofilms of selected veterinary gram-negative and gram-positive pathogenic bacteria from cattle, sheep, pigs, chicken, and turkeys. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) of ampicillin, ceftiofur, cloxacillin, oxytetracycline, penicillin G, streptomycin, tetracycline, enrofloxacin, erythromycin, gentamicin, tilmicosin, and trimethoprim-sulfadoxine for gram-positive and -negative bacteria were determined. Bacterial biofilms were readily formed on the CBD under selected conditions. The biofilms consisted of micro-colonies encased in extracellular polysaccharide material. Biofilms composed of Arcanobacterium (Actinomyces) pyogenes, Staphylococcus aureus, Staphylococcus hyicus, Streptococcus agalactiae, Corynebacterium renale, or Corynebacterium pseudotuberculosis were not killed by the antibiotics tested but as planktonic bacteria they were sensitive at low concentrations. Biofilm and planktonic Streptococcus dysgalactiae and Streptococcus suis were sensitive to penicillin, ceftiofur, cloxacillin, ampicillin, and oxytetracycline. Planktonic Escherichia coli were sensitive to enrofloxacin, gentamicin, oxytetracycline and trimethoprim/ sulfadoxine. Enrofloxacin and gentamicin were the most effective antibiotics against E. coli growing as a biofilm. Salmonella spp. and Pseudomonas aeruginosa isolates growing as planktonic populations were sensitive to enrofloxacin, gentamicin, ampicillin, oxytetracycline, and trimethoprim/sulfadoxine, but as a biofilm, these bacteria were only sensitive to enrofloxacin. Planktonic and biofilm Pasteurella multocida and Mannheimia haemolytica had similar antibiotic sensitivity profiles and were sensitive to most of the antibiotics tested. The CBD provides a valuable new technology that can be used to select antibiotics that are able to kill bacteria growing as biofilms. PMID:11989739

  9. Biofilm Formation by Gram-Negative Bacteria on Central Venous Catheter Connectors: Effect of Conditioning Films in a Laboratory Model

    Microsoft Academic Search

    R. Murga; J. M. Miller; R. M. Donlan

    2001-01-01

    Human blood components have been shown to enhance biofilm formation by gram-positive bacteria. We investigated the effect of human blood on biofilm formation on the inner lumen of needleless central venous catheter connectors by several gram-negative bacteria, specifically Enterobacter cloacae, Pseudomonas aerugi- nosa, and Pantoea agglomerans. Results suggest that a conditioning film of blood components promotes biofilm formation by these

  10. [Activity of fusidic acid on strictly anaerobic bacteria].

    PubMed

    Canzi, A M; Weber, P; Boussougant, Y

    1987-05-01

    Fusidic acid is a well known antimicrobial agent due to its narrow spectrum of activity against Gram positive bacteria and especially staphylococci. Therefore, it is after used preventively against bacterial infection in traumatology, but the susceptibility of anaerobic bacteria is not well known. We have studied, the in vitro activity of sodium fusidate against 147 strains of anaerobic bacteria. This antibiotic has a moderate activity against Bacteroides, more significant against Clostridium, Peptococcus et Peptostreptococcus; it has no bactericidal activity. Clostridium difficile is different from other anaerobic bacteria because of its slow MIC and its MBC near to its MIC. Fusidic acid could be proposed for the treatment of pseudomembranous and antibiotic-associated colitis induced by Clostridium difficile. PMID:3302863

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    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).

  12. Sexual isolation in bacteria

    Microsoft Academic Search

    Jacek Majewski

    2001-01-01

    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

  13. 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 ...

  14. Cell wall structure and function in lactic acid bacteria

    PubMed Central

    2014-01-01

    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

  15. CcpA-Dependent Carbon Catabolite Repression in Bacteria

    PubMed Central

    Warner, Jessica B.; Lolkema, Juke S.

    2003-01-01

    Carbon catabolite repression (CCR) by transcriptional regulators follows different mechanisms in gram-positive and gram-negative bacteria. In gram-positive bacteria, CcpA-dependent CCR is mediated by phosphorylation of the phosphoenolpyruvate:sugar phosphotransferase system intermediate HPr at a serine residue at the expense of ATP. The reaction is catalyzed by HPr kinase, which is activated by glycolytic intermediates. In this review, the distribution of CcpA-dependent CCR among bacteria is investigated by searching the public databases for homologues of HPr kinase and HPr-like proteins throughout the bacterial kingdom and by analyzing their properties. Homologues of HPr kinase are commonly observed in the phylum Firmicutes but are also found in the phyla Proteobacteria, Fusobacteria, Spirochaetes, and Chlorobi, suggesting that CcpA-dependent CCR is not restricted to gram-positive bacteria. In the ? and ? subdivisions of the Proteobacteria, the presence of HPr kinase appears to be common, while in the ? subdivision it is more of an exception. The genes coding for the HPr kinase homologues of the Proteobacteria are in a gene cluster together with an HPr-like protein, termed XPr, suggesting a functional relationship. Moreover, the XPr proteins contain the serine phosphorylation sequence motif. Remarkably, the analysis suggests a possible relation between CcpA-dependent gene regulation and the nitrogen regulation system (Ntr) found in the ? subdivision of the Proteobacteria. The relation is suggested by the clustering of CCR and Ntr components on the genome of members of the Proteobacteria and by the close phylogenetic relationship between XPr and NPr, the HPr-like protein in the Ntr system. In bacteria in the phylum Proteobacteria that contain HPr kinase and XPr, the latter may be at the center of a complex regulatory network involving both CCR and the Ntr system. PMID:14665673

  16. Cell wall structure and function in lactic acid bacteria.

    PubMed

    Chapot-Chartier, Marie-Pierre; Kulakauskas, Saulius

    2014-08-29

    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

  17. 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.

  18. Antibacterial Activity of Some Lactic Acid Bacteria Isolated from an Algerian Dairy Product

    PubMed Central

    Mezaini, Abdelkader; Chihib, Nour-Eddine; Dilmi Bouras, Abdelkader; Nedjar-Arroume, Naima; Hornez, Jean Pierre

    2009-01-01

    In the present study, the antibacterial effect of 20 lactic acid bacteria isolates from a traditional cheese was investigated. 6 isolates showed antibacterial effect against Gram positive bacteria. Streptococcus thermophilus T2 strain showed the wide inhibitory spectrum against the Gram positive bacteria. Growth and bacteriocin production profiles showed that the maximal bacteriocin production, by S. thermophilus T2 cells, was measured by the end of the late-log phase (90 AU ml?1) with a bacteriocine production rate of 9.3 (AU ml?1) h?1. In addition, our findings showed that the bacteriocin, produced by S. thermophilus T2, was stable over a wide pH range (4–8); this indicates that such bacteriocin may be useful in acidic as well as nonacidic food. This preliminarily work shows the potential application of autochthonous lactic acid bacteria to improve safety of traditional fermented food. PMID:20041021

  19. News and Research Good Bacteria

    E-print Network

    West, Stuart

    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

  20. A method for estimating the biomass of bacteria in aquatic sediments and its application to trophic studies

    Microsoft Academic Search

    D. J. W. Moriarty

    1975-01-01

    A method is described for estimating the biomass of bacteria in aquatic sediments by an enzymic measurement of D-lactic acid derived from hydrolysis of muramic acid. A correlation is shown between muramic acid and biomass. The Gram-negative rod bacteria contain about 20 µg muramic acid\\/mg carbon whereas the Gram-negative or Gramvariable pleomorphic and Gram-positive bacteria contain about 100 µg muramic

  1. Lipoprotein sorting in bacteria.

    PubMed

    Okuda, Suguru; Tokuda, Hajime

    2011-01-01

    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

  2. Reanimation of Ancient Bacteria

    SciTech Connect

    Russell Vreeland

    2009-01-09

    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.

  3. Bacteria, food, and cancer

    PubMed Central

    Rooks, Michelle G.

    2011-01-01

    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

  4. Manufacture of Probiotic Bacteria

    NASA Astrophysics Data System (ADS)

    Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.

    Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.

  5. Bacteria: More Than Pathogens

    NSDL National Science Digital Library

    Wassenaar, Trudy M.

    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.

  6. Glacial Lake Hides Bacteria

    NSDL National Science Digital Library

    Peplow, Mark

    2010-03-01

    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.

  7. Gram-Negative Bacteria

    Microsoft Academic Search

    Craig A. Martin

    \\u000a Gram-negative bacteria are responsible for a broad array of infections in both the ambulatory and hospital settings. Urinary\\u000a tract infections, otitis media, pneumonia, abdominal infections, and meningitis are among the common and serious diseases\\u000a caused by these pathogens. Beta-lactams including penicillins, cephalosporins, monobactams, and carbapenems, along with fluoroquinolones\\u000a and aminoglycosides, comprise the most commonly used treatment regimens for gram-negative infections.

  8. Bacteria in Confined Spaces

    NASA Astrophysics Data System (ADS)

    Wilking, Connie; Weitz, David

    2010-03-01

    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.

  9. Growing Unculturable Bacteria

    PubMed Central

    2012-01-01

    The bacteria that can be grown in the laboratory are only a small fraction of the total diversity that exists in nature. At all levels of bacterial phylogeny, uncultured clades that do not grow on standard media are playing critical roles in cycling carbon, nitrogen, and other elements, synthesizing novel natural products, and impacting the surrounding organisms and environment. While molecular techniques, such as metagenomic sequencing, can provide some information independent of our ability to culture these organisms, it is essentially impossible to learn new gene and pathway functions from pure sequence data. A true understanding of the physiology of these bacteria and their roles in ecology, host health, and natural product production requires their cultivation in the laboratory. Recent advances in growing these species include coculture with other bacteria, recreating the environment in the laboratory, and combining these approaches with microcultivation technology to increase throughput and access rare species. These studies are unraveling the molecular mechanisms of unculturability and are identifying growth factors that promote the growth of previously unculturable organisms. This minireview summarizes the recent discoveries in this area and discusses the potential future of the field. PMID:22661685

  10. 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...

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

    Microsoft Academic Search

    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

    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

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

    DOEpatents

    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

    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.

  13. ISOLATION AND IDENTIFICATION OF LACTIC ACID BACTERIA IN COCONUT TODDY (MNAZI)

    Microsoft Academic Search

    T. T. Kadere; P. M. Kutima

    2012-01-01

    Mnazi, like any other sugary plant sap can be processed into an alcoholic beverage through fermentation of the sugars present in the sap, yielding alcohol and carbon dioxide. It is sweet, dirty brown in color, containing 10-12% sugar, mainly sucrose (Okafor, 1975). The lactic acid bacteria isolated from mnazi were found to be Gram positive and catalase negative. A total

  14. Simultaneous Fluorescent Gram Staining and Activity Assessment of Activated Sludge Bacteria

    Microsoft Academic Search

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

    2002-01-01

    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

  15. Living bacteria in silica gels

    NASA Astrophysics Data System (ADS)

    Nassif, Nadine; Bouvet, Odile; Noelle Rager, Marie; Roux, Cécile; Coradin, Thibaud; Livage, Jacques

    2002-09-01

    The encapsulation of enzymes within silica gels has been extensively studied during the past decade for the design of biosensors and bioreactors. Yeast spores and bacteria have also been recently immobilized within silica gels where they retain their enzymatic activity, but the problem of the long-term viability of whole cells in an inorganic matrix has never been fully addressed. It is a real challenge for the development of sol-gel processes. Generic tests have been performed to check the viability of Escherichia coli bacteria in silica gels. Surprisingly, more bacteria remain culturable in the gel than in an aqueous suspension. The metabolic activity of the bacteria towards glycolysis decreases slowly, but half of the bacteria are still viable after one month. When confined within a mineral environment, bacteria do not form colonies. The exchange of chemical signals between isolated bacteria rather than aggregates can then be studied, a point that could be very important for 'quorum sensing'.

  16. [Incidence of anaerobic bacteria in respiratory tract infections].

    PubMed

    Kedzia, Anna; Kwapisz, Ewa; Wierzbowska, Maria

    2003-01-01

    Anaerobic bacteria are predominant components of normal oral cavity, upper respiratory tract, gastrointestinal, genital and skin flora. They are involved in infections such as pneumonia, aspiration pneumonia, lung abscess and empyema. Laboratory diagnosis of anaerobic infections is based on recovering the etiological agents from clinical materials. Appropriatte specimens include: pus, purulent fluid, biopsy specimen of lung, transtracheal aspirates and bronchoalveolar lavage (BAL). Lower respiratory infections are usually either polymicrobial or mixed anaerobic-aerobic infections. Peptostreptococcus, Fusobacterium, Prevotella and Bacteroides are the most common anaerobes. Anaerobic bacteria are susceptible to metronidazole, tinidazole (exception of Gram-positive rods), amoxicillin/clavulanate, ampicillin/sulbactam, piperacillin/tazobactam, imipenem and clindamycin. Treatment includes an antibiotics regimen with an agent active against anaerobic and aerobic bacteria (therapy with 2 or 3 antimicrobial drugs). PMID:12959026

  17. Triclosan- resistant bacteria isolated from feedlot and residential soils

    PubMed Central

    WELSCH, TANNER T.; GILLOCK, ERIC T.

    2014-01-01

    Triclosan is an antimicrobial agent that is currently incorporated into hundreds of consumer and medical products. It can be either a bacteriostatic or bactericidal agent, depending on its formulation. It has activity against Gram-positive and Gram-negative bacteria, as well as some viruses and protists. The purpose of this study was to determine whether triclosan-resistant bacteria could be isolated from the soil. Soils from cattle feedlots and residential lawns were collected and assayed for the presence of these organisms by plating samples on growth media containing triclosan. Organisms were subsequently identified by partial 16S rRNA sequencing analysis. All the organisms isolated in this study were Gram-negative rods, with members of genus Pseudomonas being particularly well represented. This result may not be surprising because Gram-negative organisms are generally more resistant to triclosan, and since Pseudomonas bacteria are known to have numerous efflux mechanisms for dealing with harmful substances. PMID:21391038

  18. Isolation and Characterization of Four Gram-Positive Nickel-Tolerant Microorganisms from Contaminated Sediments

    Microsoft Academic Search

    Joy D. Van Nostrand; Tatiana V. Khijniak; Terry J. Gentry; Michelle T. Novak; Andrew G. Sowder; Jizhong Z. Zhou; Paul M. Bertsch; Pamela J. Morris

    2007-01-01

    Microbial communities from riparian sediments contaminated with high levels of Ni and U were examined for metal-tolerant microorganisms.\\u000a Isolation of four aerobic Ni-tolerant, Gram-positive heterotrophic bacteria indicated selection pressure from Ni. These isolates\\u000a were identified as Arthrobacter oxydans NR-1, Streptomyces galbus NR-2, Streptomyces aureofaciens NR-3, and Kitasatospora cystarginea NR-4 based on partial 16S rDNA sequences. A functional gene microarray containing

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

    Microsoft Academic Search

    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

    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

  20. Teichoic acids and related cell-wall glycopolymers in Gram-positive physiology and host interactions

    Microsoft Academic Search

    Christopher Weidenmaier; Andreas Peschel

    2008-01-01

    Abstract | Most Gram-positive bacteria incorporate membrane- or peptidoglycan-attached carbohydrate-based polymers into their cell envelopes. Such cell-wall glycopolymers (CWGs) often have highly variable structures and have crucial roles in protecting, connecting and controlling the major envelope constituents. Further important roles of CWGs in host-cell adhesion, inflammation and immune activation have also been described in recent years. Identifying and harnessing highly

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

    Microsoft Academic Search

    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

    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

  2. Activating transcription in bacteria.

    PubMed

    Lee, David J; Minchin, Stephen D; Busby, Stephen J W

    2012-01-01

    Bacteria use a variety of mechanisms to direct RNA polymerase to specific promoters in order to activate transcription in response to growth signals or environmental cues. Activation can be due to factors that interact at specific promoters, thereby increasing transcription directed by these promoters. We examine the range of architectures found at activator-dependent promoters and outline the mechanisms by which input from different factors is integrated. Alternatively, activation can be due to factors that interact with RNA polymerase and change its preferences for target promoters. We summarize the different mechanistic options for activation that are focused directly on RNA polymerase. PMID:22726217

  3. Magnetosomes in Magnetotactic Bacteria

    Microsoft Academic Search

    André Scheffel; Dirk Schüler

    The ability of magnetotactic bacteria (MTB) to orient and migrate along magnetic field lines is based\\u000a on magnetosomes, which are membrane-enclosed intracellular crystals of a magnetic iron mineral. The\\u000a biomineralization of magnetosomes is a process with genetic control over the accumulation of iron,\\u000a the deposition of the magnetic crystal within a specific compartment, as well as their intracellular\\u000a assembly and alignment into chain-like

  4. Can entropy save bacteria?

    E-print Network

    Suckjoon Jun

    2008-08-29

    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.

  5. Trail following by gliding bacteria.

    PubMed Central

    Burchard, R P

    1982-01-01

    Slime trails, which are deposited on surfaces by gliding bacteria and which serve as preferential pathways for gliding motility, were tested for the species specificity of their support of movement. Among the pairs of bacteria tested, a variety of gliding bacteria and a flagellated bacterium moved along trails of unrelated species. Thus, the trails did not serve as pheromones. Rather, they may have guided gliding elasticotactically. Some biological implications of this finding are considered. Images PMID:6811562

  6. Bacteria within ovules and seeds.

    PubMed Central

    Mundt, J O; Hinkle, N F

    1976-01-01

    Surface-sterilized ovules and seeds of 27 species of plants were cultured in the water of syneresis of a nutrient medium low in agar content. Bacteria were obtained from 30% of the ovules, 15% of the seeds of herbaceous plants, 16% of the seeds of woody plants, 5.4% of the overwintered noncereal seeds, and 13.5% of overwintered cereal seeds. In no instance did every ovule or seed of a plant species contain bacteria. No bacteria were obtained from the hard, waxy seeds of mimosa or yellowwood. They were not obtained from ovules with unbroken coats or from seeds with coats that were not ruptured during the swelling of the seed. Only one species of bacteria was recovered in 93% of the instances in which bacteria were obtained. Bacteria were obtained from seeds that were embedded in the acidic parenchyma of the lemon or surrounded by the thickened flesh of the cucurbits. The bacteria were distributed among 19 genera and 46 species. The species isolated in greatest numbers were Bacillus megaterium, B. cereus, Erwinia herbicola, Flavobacterium devorans, and Pseudomonas fluorescens. Bacteria recovered less frequently were in the genera Achromobacter, Acinetobacter, Alcaligenes, Brevibacterium, Corynebacterium, Cytophaga, Leuconostoc, Micrococcus, Nocardia, Proteus, Streptococcus, Streptomyces, and Xanthomonas. Members of 11 genera and 15 species of bacteria were isolated once. PMID:984839

  7. Gram-positive cocci isolated from slaughtered poultry.

    PubMed

    Turtura, G C; Lorenzelli, P

    1994-06-01

    Gram-positive cocci were found in all meat samples of poultry slaughtered and processed for retail sale, at incidence rates ranging from 10(2) CFU/ml to 1.35 x 10(6) CFU/ml and a mode between 8 x 10(5) and 9 x 10(5) CFU/ml for 75% of the samples. The 93 isolated strains were identified as belonging to the following species: Enterococcus faecalis (48 strains), E. faecium (16), E. avium (7), E. durans (4), Aerococcus viridans (10), Streptococcus morbillorum (2), S. salivarius (1), S. sanguis (1), S. "milleri" (1), S. pneumoniae (1), S. acidominimus (1), and Gemella haemolysans (1). These species, which mainly colonize the intestinal tract, but may also be found in other parts of both the human and animal body, are pathogens or potentially such. Their presence is an indication of the fecal contamination of meat processed following gutting of slaughtered chickens (endogenous contamination). A count of the Gram-positive cocci and enterobacteria detected showed that enterococci were present in a far greater number than coliform bacteria. PMID:7921897

  8. Programmed Death in Bacteria

    PubMed Central

    Lewis, Kim

    2000-01-01

    Programmed cell death (PCD) in bacteria plays an important role in developmental processes, such as lysis of the mother cell during sporulation of Bacillus subtilis and lysis of vegetative cells in fruiting body formation of Myxococcus xanthus. The signal transduction pathway leading to autolysis of the mother cell includes the terminal sporulation sigma factor E?K, which induces the synthesis of autolysins CwlC and CwlH. An activator of autolysin in this and other PCD processes is yet to be identified. Autolysis plays a role in genetic exchange in Streptococcus pneumoniae, and the gene for the major autolysin, lytA, is located in the same operon with recA. DNA from lysed cells is picked up by their neighbors and recombined into the chromosome by RecA. LytA requires an unknown activator controlled by a sensory kinase, VncS. Deletion of vncS inhibits autolysis and also decreases killing by unrelated antibiotics. This observation suggests that PCD in bacteria serves to eliminate damaged cells, similar to apoptosis of defective cells in metazoa. The presence of genes affecting survival without changing growth sensitivity to antibiotics (vncS, lytA, hipAB, sulA, and mar) indicates that bacteria are able to control their fate. Elimination of defective cells could limit the spread of a viral infection and donate nutrients to healthy kin cells. An altruistic suicide would be challenged by the appearance of asocial mutants without PCD and by the possibility of maladaptive total suicide in response to a uniformly present lethal factor or nutrient depletion. It is proposed that a low rate of mutation serves to decrease the probability that asocial mutants without PCD will take over the population. It is suggested that PCD is disabled in persistors, rare cells that are resistant to killing, to ensure population survival. It is suggested that lack of nutrients leads to the stringent response that suppresses PCD, producing a state of tolerance to antibiotics, allowing cells to discriminate between nutrient deprivation and unrepairable damage. High levels of persistors are apparently responsible for the extraordinary survival properties of bacterial biofilms, and genes affecting persistence appear to be promising targets for development of drugs aimed at eradicating recalcitrant infections. PCD in unicellular eukaryotes is also considered, including aging in Saccharomyces cerevisiae. Apoptosis-like elimination of defective cells in S. cerevisiae and protozoa suggests that all unicellular life forms evolved altruistic programmed death that serves a variety of useful functions. PMID:10974124

  9. Antimicrobial activity of the carnivorous plant Dionaea muscipula against food-related pathogenic and putrefactive bacteria.

    PubMed

    Ogihara, Hirokazu; Endou, Fumiko; Furukawa, Soichi; Matsufuji, Hiroshi; Suzuki, Kouichi; Anzai, Hiroshi

    2013-01-01

    Solvent extracts from the carnivorous plant Dionaea muscipula (Venus flytrap) were prepared using eight different organic solvents, and examined for antibacterial activity against food-related pathogenic and putrefactive bacteria. All solvent extracts showed higher antibacterial activity against gram positive bacteria than against gram negative bacteria. The TLC-bioautography analysis of the extracts revealed that a yellow spot was detected at Rf value of 0.85, which showed strong antibacterial activity. The UV, MS, and NMR analyses revealed that the antibacterial compound was plumbagin. PMID:24077538

  10. Bacteria tracking by in vivo magnetic resonance imaging

    PubMed Central

    2013-01-01

    Background Different non-invasive real-time imaging techniques have been developed over the last decades to study bacterial pathogenic mechanisms in mouse models by following infections over a time course. In vivo investigations of bacterial infections previously relied mostly on bioluminescence imaging (BLI), which is able to localize metabolically active bacteria, but provides no data on the status of the involved organs in the infected host organism. In this study we established an in vivo imaging platform by magnetic resonance imaging (MRI) for tracking bacteria in mouse models of infection to study infection biology of clinically relevant bacteria. Results We have developed a method to label Gram-positive and Gram-negative bacteria with iron oxide nano particles and detected and pursued these with MRI. The key step for successful labeling was to manipulate the bacterial surface charge by producing electro-competent cells enabling charge interactions between the iron particles and the cell wall. Different particle sizes and coatings were tested for their ability to attach to the cell wall and possible labeling mechanisms were elaborated by comparing Gram-positive and -negative bacterial characteristics. With 5-nm citrate-coated particles an iron load of 0.015 ± 0.002 pg Fe/bacterial cell was achieved for Staphylococcus aureus. In both a subcutaneous and a systemic infection model induced by iron-labeled S. aureus bacteria, high resolution MR images allowed for bacterial tracking and provided information on the morphology of organs and the inflammatory response. Conclusion Labeled with iron oxide particles, in vivo detection of small S. aureus colonies in infection models is feasible by MRI and provides a versatile tool to follow bacterial infections in vivo. The established cell labeling strategy can easily be transferred to other bacterial species and thus provides a conceptual advance in the field of molecular MRI. PMID:23714179

  11. Aminopeptidase Profiles of Various Bacteria

    PubMed Central

    Westley, J. W.; Anderson, P. J.; Close, V. A.; Halpern, B.; Lederberg, E. M.

    1967-01-01

    The aminopeptidase specificity of 24 strains of bacteria was determined fluorometrically by use of a series of ?-amino acid ?-naphthylamides as substrates. Provided that strict control over medium and growth time was adhered to, a reproducible profile of aminopeptidase activity was obtained which could be used for the identification of bacteria. PMID:4963444

  12. Bacteria, toxins, and the peritoneum

    Microsoft Academic Search

    Toni Hau

    1990-01-01

    Intraperitoneal infections are caused by members of the gastrointestinal flora, mainlyEscherichia coli, enterococci, Klebsiella, Enterobacter, Proteus, Bacteroides, anaerobic cocci, Clostridia, and Fusobacteria. The Gram-negative aerobic bacteria exert their pathogenic potential mainly through endotoxin which acts by way of mediators, causing systemic septic response and, initially, the local response of the peritoneal cavity. The main virulence factors of anaerobic bacteria are

  13. In vitro antibacterial activities and mechanism of sugar fatty acid esters against five food-related bacteria.

    PubMed

    Zhao, Lei; Zhang, Heyan; Hao, Tianyang; Li, Siran

    2015-11-15

    The objective of this study was to evaluate the antibacterial activities of sugar fatty acid esters, with different fatty acid and saccharide moieties, against five food-related bacteria including Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium. Sucrose monocaprate showed the strongest antibacterial activity against all tested bacteria, especially Gram-positive bacteria. The minimum inhibitory concentrations (MICs) for Gram-positive bacteria and Gram-negative bacteria were 2.5 and 10mM, respectively. The minimum bactericidal concentrations (MBCs) for Gram-positive bacteria were 10mM. Time-kill assay also showed that sucrose monocaprate significantly inhibit the growth of tested bacteria. The permeability of the cell membrane and intracellular proteins were both changed by sucrose monocaprate according to cell constituents' leakage, SDS-PAGE and scanning electron microscope assays. It is suggested that sucrose monocaprate, with both emulsifying and antibacterial activities, have a potential to serve as a safe multifunctional food additive in food industries. PMID:25977039

  14. Phosphoenolpyruvate:carbohydrate phosphotransferase systems of bacteria.

    PubMed

    Postma, P W; Lengeler, J W; Jacobson, G R

    1993-09-01

    Numerous gram-negative and gram-positive bacteria take up carbohydrates through the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS). This system transports and phosphorylates carbohydrates at the expense of PEP and is the subject of this review. The PTS consists of two general proteins, enzyme I and HPr, and a number of carbohydrate-specific enzymes, the enzymes II. PTS proteins are phosphoproteins in which the phospho group is attached to either a histidine residue or, in a number of cases, a cysteine residue. After phosphorylation of enzyme I by PEP, the phospho group is transferred to HPr. The enzymes II are required for the transport of the carbohydrates across the membrane and the transfer of the phospho group from phospho-HPr to the carbohydrates. Biochemical, structural, and molecular genetic studies have shown that the various enzymes II have the same basic structure. Each enzyme II consists of domains for specific functions, e.g., binding of the carbohydrate or phosphorylation. Each enzyme II complex can consist of one to four different polypeptides. The enzymes II can be placed into at least four classes on the basis of sequence similarity. The genetics of the PTS is complex, and the expression of PTS proteins is intricately regulated because of the central roles of these proteins in nutrient acquisition. In addition to classical induction-repression mechanisms involving repressor and activator proteins, other types of regulation, such as antitermination, have been observed in some PTSs. Apart from their role in carbohydrate transport, PTS proteins are involved in chemotaxis toward PTS carbohydrates. Furthermore, the IIAGlc protein, part of the glucose-specific PTS, is a central regulatory protein which in its nonphosphorylated form can bind to and inhibit several non-PTS uptake systems and thus prevent entry of inducers. In its phosphorylated form, P-IIAGlc is involved in the activation of adenylate cyclase and thus in the regulation of gene expression. By sensing the presence of PTS carbohydrates in the medium and adjusting the phosphorylation state of IIAGlc, cells can adapt quickly to changing conditions in the environment. In gram-positive bacteria, it has been demonstrated that HPr can be phosphorylated by ATP on a serine residue and this modification may perform a regulatory function. PMID:8246840

  15. Magnetic Microstructure of Magnetotactic Bacteria by

    E-print Network

    Dunin-Borkowski, Rafal E.

    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

  16. Urine Isn't Free of Bacteria

    MedlinePLUS

    ... fullstory_151843.html 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 ...

  17. Silver enhances antibiotic activity against gram-negative bacteria.

    PubMed

    Morones-Ramirez, Jose Ruben; Winkler, Jonathan A; Spina, Catherine S; Collins, James J

    2013-06-19

    A declining pipeline of clinically useful antibiotics has made it imperative to develop more effective antimicrobial therapies, particularly against difficult-to-treat Gram-negative pathogens. Silver has been used as an antimicrobial since antiquity, yet its mechanism of action remains unclear. We show that silver disrupts multiple bacterial cellular processes, including disulfide bond formation, metabolism, and iron homeostasis. These changes lead to increased production of reactive oxygen species and increased membrane permeability of Gram-negative bacteria that can potentiate the activity of a broad range of antibiotics against Gram-negative bacteria in different metabolic states, as well as restore antibiotic susceptibility to a resistant bacterial strain. We show both in vitro and in a mouse model of urinary tract infection that the ability of silver to induce oxidative stress can be harnessed to potentiate antibiotic activity. Additionally, we demonstrate in vitro and in two different mouse models of peritonitis that silver sensitizes Gram-negative bacteria to the Gram-positive-specific antibiotic vancomycin, thereby expanding the antibacterial spectrum of this drug. Finally, we used silver and antibiotic combinations in vitro to eradicate bacterial persister cells, and show both in vitro and in a mouse biofilm infection model that silver can enhance antibacterial action against bacteria that produce biofilms. This work shows that silver can be used to enhance the action of existing antibiotics against Gram-negative bacteria, thus strengthening the antibiotic arsenal for fighting bacterial infections. PMID:23785037

  18. Role of commensal gut bacteria in inflammatory bowel diseases

    PubMed Central

    Loh, Gunnar; Blaut, Michael

    2012-01-01

    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

  19. Development of Mucosal Vaccines Based on Lactic Acid Bacteria

    NASA Astrophysics Data System (ADS)

    Bermúdez-Humarán, Luis G.; Innocentin, Silvia; Lefèvre, Francois; Chatel, Jean-Marc; Langella, Philippe

    Today, sufficient data are available to support the use of lactic acid bacteria (LAB), notably lactococci and lactobacilli, as delivery vehicles for the development of new mucosal vaccines. These non-pathogenic Gram-positive bacteria have been safely consumed by humans for centuries in fermented foods. They thus constitute an attractive alternative to the attenuated pathogens (most popular live vectors actually studied) which could recover their pathogenic potential and are thus not totally safe for use in humans. This chapter reviews the current research and advances in the use of LAB as live delivery vectors of proteins of interest for the development of new safe mucosal vaccines. The use of LAB as DNA vaccine vehicles to deliver DNA directly to antigen-presenting cells of the immune system is also discussed.

  20. 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.

  1. Sampling bacteria with a laser

    NASA Astrophysics Data System (ADS)

    Schwarzwälder, Kordula; Rutschmann, Peter

    2014-05-01

    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.

  2. Sampling for Bacteria in Wells

    E-print Network

    Lesikar, Bruce J.

    2001-11-15

    Sampling for Bacteria in Wells E-126 11/01 Water samples for bacteria tests must always be col- lected in a sterile container. The procedure for collect- ing a water sample is as follows: 1. Obtain a sterile container from a Health Department... immediately after collecting water sample. Refrigerate the sample and transport it to the laborato- ry (in an ice chest) as soon after collection as possible (six hours is best, but up to 30 hours). Many labs will not accept bacteria samples on Friday so check...

  3. Inactivation ofBiofilm Bacteria

    Microsoft Academic Search

    MARK W. LECHEVALLIER; CHERYL D. CAWTHON; RAMON G. LEE

    1988-01-01

    Thecurrent project was developed toexamine inactivation ofbiofilm bacteria andtocharacterize the interaction ofbiocides withpipesurfaces. Unattached bacteria were quite susceptible tothevariety of disinfectants tested. Viable bacterial counts were reduced 99%byexposureto0.08 mg ofhypochlorous acid (pH7.0) perliter (1to2°C) for1min.Formonochloramine, 94mg\\/liter wasrequired tokill 99%ofthebacteria within 1min.Theseresults wereconsistent withthose found byother investigators. Biofilm bacteria grown on thesurfaces ofgranular activated carbon particles, metal coupons,orglass microscope slides were

  4. Heterogeneity within Human-Derived Centers for Disease Control and Prevention (CDC) Coryneform Group ANF1Like Bacteria and Description of Corynebacterium auris sp. nov

    Microsoft Academic Search

    GUIDO FUNKE; PAUL A. LAWSON; MATTHEW D. COLLINS

    1995-01-01

    Recently, Centers for Disease Control and Prevention coryneform group ANF-1 bacteria were described as Corynebacterium afermentans, and group ANF-1-like bacteria were described as Turicella otitidis. Over a 1.5-year period 10 strains of a previously undescribed, gram-positive, rod-shaped organism that was not partially acid fast and resembled ANF-1-like bacteria were isolated from different pediatric patients with ear infections. These previously undescribed

  5. Isolation and Characterization of Polycyclic Aromatic Hydrocarbon-Degrading Bacteria Associated with the Rhizosphere of Salt Marsh Plants

    Microsoft Academic Search

    L. L. Daane; I. Harjono; G. J. Zylstra; M. M. Haggblom

    2001-01-01

    Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were isolated from contaminated estuarine sediment and salt marsh rhizosphere by enrichment using either naphthalene, phenanthrene, or biphenyl as the sole source of carbon and energy. Pasteurization of samples prior to enrichment resulted in isolation of gram-positive, spore-forming bacteria. The isolates were characterized using a variety of phenotypic, morpho- logic, and molecular properties. Identification of

  6. Bacteriocin Detection from Whole Bacteria by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

    Microsoft Academic Search

    Thomas Hindre; Sandrine Didelot; Jean-Paul Le Pennec; Dominique Haras; Alain Dufour; Karine Vallee-Rehel

    2003-01-01

    Class I bacteriocins (lantibiotics) and class II bacteriocins are antimicrobial peptides secreted by gram- positive bacteria. Using two lantibiotics, lacticin 481 and nisin, and the class II bacteriocin coagulin, we showed that bacteriocins can be detected without any purification from whole producer bacteria grown on plates by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). When we compared the

  7. Extracellular Vesicles Produced by the Gram-positive Bacterium Bacillus subtilis are Disrupted by the Lipopeptide Surfactin

    PubMed Central

    Brown, Lisa; Kessler, Anne; Cabezas-Sanchez, Pablo; Luque-Garcia, Jose L.; Casadevall, Arturo

    2014-01-01

    Summary Previously, extracellular vesicle production in Gram-positive bacteria was dismissed due to the absence of an outer membrane, where Gram-negative vesicles originate, and the difficulty in envisioning how such a process could occur through the cell wall. However, recent work has shown that Gram-positive bacteria produce extracellular vesicles and that the vesicles are biologically active. In this study, we show that Bacillus subtilis produces extracellular vesicles similar in size and morphology to other bacteria, characterized vesicles using a variety of techniques, provide evidence that these vesicles are actively produced by cells, show differences in vesicle production between strains, and identified a mechanism for such differences based on vesicle disruption. We found that in wild strains of B. subtilis, surfactin disrupted vesicles while in laboratory strains harboring a mutation in the gene sfp, vesicles accumulated in the culture supernatant. Surfactin not only lysed B. subtilis vesicles, but also vesicles from Bacillus anthracis, indicating a mechanism that crossed species boundaries. To our knowledge, this is the first time a gene and a mechanism has been identified in the active disruption of extracellular vesicles and subsequent release of vesicular cargo in Gram-positive bacteria. We also identify a new mechanism of action for surfactin. PMID:24826903

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    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.

  9. Activities of the Semisynthetic Glycopeptide LY191145 against Vancomycin-Resistant Enterococci and Other Gram-Positive Bacteria

    Microsoft Academic Search

    THALIA I. NICAS; DEBORAH L. MULLEN; JANE E. FLOKOWITSCH; DAVID A. PRESTON; NANCY J. SNYDER; ROBERT E. STRATFORD; ANDROBIN D. G. COOPER

    1995-01-01

    LY191145 is the prototype of a series of compounds with activities against vancomycin-resistant enterococci derived by modification of the glycopeptide antibiotic LY264826. LY191145 had MICs for vancomycin- and teicoplanin-resistant enterococci of <4 mg\\/ml for 50% of isolates and <16 mg\\/ml for 90% of isolates. Its MICs for vancomycin-resistant, teicoplanin-susceptible enterococci were 1 to 8 mg\\/ml. LY191145 retains the potent activities

  10. 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...

  11. Tuberculosis (TB) is caused by gram-positive bac-teria known as the Mycobacterium tuberculosis complex

    E-print Network

    whistle repertoires BRENDA McCOWAN*, SEAN F. HANSER & LAURANCE R. DOYLE *California Regional Primate communicative reper- toires objectively, and for elucidating repertoires of unknown structure or function (Pea

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

    PubMed Central

    2012-01-01

    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

  13. The PECACE domain: a new family of enzymes with potential peptidoglycan cleavage activity in Gram-positive bacteria

    Microsoft Academic Search

    Estelle Pagliero; Otto Dideberg; Thierry Vernet; Anne Marie Di Guilmi

    2005-01-01

    BACKGROUND: The metabolism of bacterial peptidoglycan is a dynamic process, synthases and cleavage enzymes are functionally coordinated. Lytic Transglycosylase enzymes (LT) are part of multienzyme complexes which regulate bacterial division and elongation. LTs are also involved in peptidoglycan turnover and in macromolecular transport systems. Despite their central importance, no LTs have been identified in the human pathogen Streptococcus pneumoniae. We

  14. New Vector for Efficient Allelic Replacement in Naturally Nontransformable, Low-GC-Content, Gram-Positive Bacteria

    Microsoft Academic Search

    Maryvonne Arnaud; Arnaud Chastanet; Michel Debarbouille

    2004-01-01

    The study of chromosomal genes and the modification of bacterial strains require the development of new strategies and new genetic tools to facilitate the rapid screening of recombi- nant clones. Molecular genetic analyses require the exchange by homologous recombination of a chromosomal gene by a mutated allele or inactivated copy, and several strategies have been developed for generating gene replacements

  15. Antimicrobial activities of Iranian sumac and avishan-e shirazi ( Zataria multiflora) against some food-borne bacteria

    Microsoft Academic Search

    Mohammad Reza Fazeli; Gholamreza Amin; Mohammad Mahdi Ahmadian Attari; Hesam Ashtiani; Hossein Jamalifar; Nasrin Samadi

    2007-01-01

    Food poisoning originating from contaminated foods by both Gram-positive and Gram-negative bacteria causes concern to society and to the industry. Spices have been used safely since ancient times as food flavoring agents and also as herbal medicines and are now mainly considered “generally regarded as safe” (GRAS). Antimicrobial effects of two spices used in Iranian traditional medicine were investigated against

  16. Simple filter paper procedure for estimation of glucose uptake via group translocation by whole-cell suspensions of bacteria.

    PubMed

    Germaine, G R; Tellefson, L M

    1981-03-01

    A simple and rapid filter paper technique is described for processing samples from glucose uptake studies with whole cells of gram-positive or gram-negative bacteria that transport glucose via group translocation. The procedure yields results equivalent to those obtained with a conventional membrane filtration method and requires no special filtration equipment or source of vacuum. PMID:7013712

  17. Mechanism of gram variability in select bacteria.

    PubMed

    Beveridge, T J

    1990-03-01

    Gram stains were performed on strains of Actinomyces bovis, Actinomyces viscosus, Arthrobacter globiformis, Bacillus brevis, Butyrivibrio fibrisolvens, Clostridium tetani, Clostridium thermosaccharolyticum, Corynebacterium parvum, Mycobacterium phlei, and Propionibacterium acnes, using a modified Gram regimen that allowed the staining process to be observed by electron microscopy (J. A. Davies, G. K. Anderson, T. J. Beveridge, and H. C. Clark, J. Bacteriol. 156:837-845, 1983). Furthermore, since a platinum salt replaced the iodine mordant of the Gram stain, energy-dispersive X-ray spectroscopy could evaluate the stain intensity and location by monitoring the platinum signal. These gram-variable bacteria could be split into two groups on the basis of their staining responses. In the Actinomyces-Arthrobacter-Corynebacterium-Mycobacterium-Propionibacterium group, few cells became gram negative until the exponential growth phase; by mid-exponential phase, 10 to 30% of the cells were gram negative. The cells that became gram negative were a select population of the culture, had initiated septum formation, and were more fragile to the stress of the Gram stain at the division site. As cultures aged to stationary phase, there was a relatively slight increase toward gram negativity (now 15 to 40%) due to the increased lysis of nondividing cells by means of lesions in the side walls; these cells maintained their rod shape but stained gram negative. Those in the Bacillus-Butyrivibrio-Clostridium group also became gram negative as cultures aged but by a separate set of events. These bacteria possessed more complex walls, since they were covered by an S layer. They stained gram positive during lag and the initial exponential growth phases, but as doubling times increased, the wall fabric underlying the S layer became noticeably thinner and diffuse, and the cells became more fragile to the Gram stain. By stationary phase, these cultures were virtually gram negative. PMID:1689718

  18. Where Bacteria and Languages Concur

    NSDL National Science Digital Library

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

    2009-01-23

    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.

  19. Taxonomy of phosphate solublizing bacteria

    Microsoft Academic Search

    P. Kämpfer

    Although phosphate solubilizing capabilities seem to be widespread within bacterial taxa, it is surprising, that the description\\u000a of phosphate solubilizing bacteria is restricted to relatively few bacterial genera. Among the bacteria, strains belonging\\u000a to the genus Rhizobium and related organisms have been investigated most extensively until now. In addition, several other organisms belonging to\\u000a taxonomically different and phylogenetic largely unrelated

  20. Methanogenic bacteria in mangrove sediments

    Microsoft Academic Search

    R. Mohanraju; R. Natarajan

    1992-01-01

    The occurrence of methanogenic bacteria in the Kodiakkarai (10° 18' N; 79° 52' E) mangrove sediments, whereAvicennia spp are predominant, was studied. Trimethylamine under N2:CO2 (80:20% v\\/v) was used as the substrate. Most Probable Number (MPN) of methanogenic bacteria was determined for a period of one year from July 1987 to June 1988 with monthly sampling. The methanogenic bacterial populations

  1. MICROBIOLOGY: How Bacteria Respire Minerals

    NSDL National Science Digital Library

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

    2001-05-18

    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.

  2. Genetic resources of nodule bacteria

    Microsoft Academic Search

    M. L. Roumiantseva

    2009-01-01

    Nodule bacteria (rhizobia) form highly specific symbiosis with leguminous plants. The efficiency of accumulation of biological\\u000a nitrogen depends on molecular-genetic interaction between the host plant and rhizobia. Genetic characteristics of microsymbiotic\\u000a strains are crucial in developing highly productive and stress-resistant symbiotic pairs: rhizobium strain-host plant cultivar\\u000a (species). The present review considers the issue of studying genetic resources of nodule bacteria

  3. Bioreporter bacteria for landmine detection

    SciTech Connect

    Burlage, R.S. [Oak Ridge National Lab., TN (United States); Youngblood, T. [Frisby Technologies, Aiken, SC (United States); Lamothe, D. [American Technologies, Inc., Huntsville, AL (United States). Ordnance/Explosives Environmental Services Div.

    1998-04-01

    Landmines (and other UXO) gradually leak explosive chemicals into the soil at significant concentrations. Bacteria, which have adapted to scavenge low concentrations of nutrients, can detect these explosive chemicals. Uptake of these chemicals results in the triggering of specific bacterial genes. The authors have created genetically recombinant bioreporter bacteria that detect small concentrations of energetic chemicals. These bacteria are genetically engineered to produce a bioluminescent signal when they contact specific explosives. A gene for a brightly fluorescent compound can be substituted for increased sensitivity. By finding the fluorescent bacteria, you find the landmine. Detection might be accomplished using stand-off illumination of the minefield and GPS technology, which would result in greatly reduced risk to the deminers. Bioreporter technology has been proven at the laboratory scale, and will be tested under field conditions in the near future. They have created a bacterial strain that detects sub-micromolar concentrations of o- and p-nitrotoluene. Related bacterial strains were produced using standard laboratory protocols, and bioreporters of dinitrotoluene and trinitrotoluene were produced, screening for activity with the explosive compounds. Response time is dependent on the growth rate of the bacteria. Although frill signal production may require several hours, the bacteria can be applied over vast areas and scanned quickly, producing an equivalent detection speed that is very fast. This technology may be applicable to other needs, such as locating buried explosives at military and ordnance/explosive manufacturing facilities.

  4. [Electron microscope investigation of bacteria associated with the tegument of the tapeworm species Eubothrium rugosum, a parasite of the intestine of burbot].

    PubMed

    Poddubnaia, L G

    2005-01-01

    Bacteria associated with the tegument of the tapeworm species Eubothrium rugosum (Cestoda, Pseudophyllidea) parasitizing the intestine of burbot (Lota lota) were studied using transmission and scanning electron microscopy. Three morphological types of the bacteria were revealed. Bacteria of the first type are localized between microtrichia and fit to them closely. Bacteria of the second (gram-positive) and third (gram-negative) types are localized over microtrichia of the tegument and do not attach to the surface. Physiological functions of the bacteria are discussed. PMID:16134784

  5. In Vitro and In Vivo Activities of Tigecycline (GAR936), Daptomycin, and Comparative Antimicrobial Agents against Glycopeptide-Intermediate Staphylococcus aureus and Other Resistant Gram-Positive Pathogens

    Microsoft Academic Search

    Peter J. Petersen; Patricia A. Bradford; William J. Weiss; Timothy M. Murphy; P. E. Sum; Steven J. Projan

    2002-01-01

    Tigecycline (GAR-936) and daptomycin are potent antibacterial compounds in advanced stages of clinical trials. These novel agents target multiply resistant pathogenic bacteria. Daptomycin is principally active against gram-positive bacteria, while tigecycline has broad-spectrum activity. When tested by the standard protocols of the National Committee for Clinical Laboratory Standards in Mueller-Hinton broth II, tigecycline was more active than daptomycin (MICs at

  6. Bacteria Galore by Sunday at Four

    NSDL National Science Digital Library

    Mel Rosenberg

    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.

  7. Opioid Exacerbation of Gram-positive sepsis, induced by Gut Microbial Modulation, is Rescued by IL-17A Neutralization

    PubMed Central

    Meng, Jingjing; Banerjee, Santanu; Li, Dan; Sindberg, Gregory M.; Wang, Fuyuan; Ma, Jing; Roy, Sabita

    2015-01-01

    Sepsis is the predominant cause of mortality in ICUs, and opioids are the preferred analgesic in this setting. However, the role of opioids in sepsis progression has not been well characterized. The present study demonstrated that morphine alone altered the gut microbiome and selectively induced the translocation of Gram-positive gut bacteria in mice. Using a murine model of poly-microbial sepsis, we further demonstrated that morphine treatment led to predominantly Gram-positive bacterial dissemination. Activation of TLR2 by disseminated Gram-positive bacteria induced sustained up-regulation of IL-17A and IL-6. We subsequently showed that overexpression of IL-17A compromised intestinal epithelial barrier function, sustained bacterial dissemination and elevated systemic inflammation. IL-17A neutralization protected barrier integrity and improved survival in morphine-treated animals. We further demonstrated that TLR2 expressed on both dendritic cells and T cells play essential roles in IL-17A production. Additionally, intestinal sections from sepsis patients on opioids exhibit similar disruption in gut epithelial integrity, thus establishing the clinical relevance of this study. This is the first study to provide a mechanistic insight into the opioid exacerbation of sepsis and show that neutralization of IL-17A might be an effective therapeutic strategy to manage Gram-positive sepsis in patients on an opioid regimen. PMID:26039416

  8. Transcriptomic response of immune signalling pathways in intestinal epithelial cells exposed to lipopolysaccharides, Gram-negative bacteria or potentially probiotic microbes.

    PubMed

    Audy, J; Mathieu, O; Belvis, J; Tompkins, T A

    2012-12-01

    In order to understand the appropriate use of potentially probiotic Gram-positive microbes through their introduction in the gut microbiome, it is necessary to understand the influence of individual bacteria on the host-response system at a cellular level. In the present study, we have shown that lipopolysaccharides, flagellated Gram-negative bacteria, potentially probiotic Gram-positive bacteria and yeast interact differently with human intestinal epithelial cells with a custom-designed expression microarray evaluating 17 specific host-response pathways. Only lipopolysaccharides and flagellated Gram-negative bacteria induced inflammatory response, while a subset of Gram-positive microbes had anti-inflammatory potential. The main outcome from the study was the differential regulation of the central mitogen-activated protein kinase signalling pathway by these Gram-positive microbes versus commensal/pathogenic Gram-negative bacteria. The microarray was efficient to highlight the impact of individual bacteria on the response of intestinal epithelial cells, but quantitative real-time polymerase chain reaction validation demonstrated some underestimation for down-regulated genes by the microarray. This immune array will allow us to better understand the mechanisms underlying microbe-induced host immune responses. PMID:23234729

  9. Commensal bacteria as a novel delivery system for subunit vaccines directed against agents of bioterrorism.

    PubMed

    Wilson, Rebecca L; Hruby, Dennis E

    2005-06-17

    Following the anthrax attacks of 2001 and the recent SARS outbreak, concerns about emerging and re-emerging infectious diseases have catalyzed a renewed interest in developing new vaccination strategies that provide rapid and flexible response options to future threats. Because the probability of encountering one of these exotic agents is unknown, it is essential that new vaccine formulations employ methods that provide effective protection and extremely good safety profiles if they are to be used by either military or civilian populations. One approach, which potentially satisfies these criteria, is the use of live recombinant Gram-positive commensal bacteria as expression vectors. This review provides an overview of the system, its advantages and limitations, and details an example of how Gram-positive commensal bacteria are being developed as a fifth generation vaccine against a Class A biowarfare pathogen, namely smallpox. PMID:15935879

  10. Characterization of lactic acid bacteria and other gut bacteria in pigs by a macroarraying method.

    PubMed

    Thanantong, Narut; Edwards, Sandra; Sparagano, Olivier A E

    2006-10-01

    Lactic acid bacteria (LAB) consist of many genera, Gram-positive, and nonspore-forming micro-organisms; some members being used as probiotics while some others have negative effects on pig health. Bacterial species in the gastrointestinal tract can produce antibacterial substances, reduce serum cholesterol in their host, or can be responsible for growth reduction, diarrhea, and intestinal epithelial damage. It is therefore important for the pig industry to evaluate the impact of food and farm management on the presence of "good" or "bad" bacteria and the risk for consumers. This articles focuses on the molecular identification of gut microflora species following different diets given to pigs in UK and correlating the data on growth, health, and welfare. First of all, pig feces were individually collected from sows before and after farrowing and also from piglets before and after weaning over several months. Bacteria colonies were grown on MRS agar plates from feces and DNA was extracted (QIAamp DNA stool kit) and amplified using 16S rDNA (27f and 519r) primers. DNA sequencing and sequence alignment allowed us to identify species-specific zones, which were used as probes in a macroarray system also known as reverse line blot hybridization. Some probes were found to be species specific for the following species: Lactobacillus acidophilus, L. animalis, L. gallinarum, L. kitasanotis, L salivarius, Streptococcus alactolyticus, S. hyointestinalis, and Sarcina ventriculi. Actual studies are now focusing on the impact of diets of the microflora in different gut parts and at different stages of the animal's life. PMID:17135526

  11. Host-Bacteria Crosstalk at the Dentogingival Junction

    PubMed Central

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

    2012-01-01

    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

  12. 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...

  13. Synergy of nitric oxide and silver sulfadiazine against gram-negative, gram-positive, and antibiotic-resistant pathogens.

    PubMed

    Privett, Benjamin J; Deupree, Susan M; Backlund, Christopher J; Rao, Kavitha S; Johnson, C Bryce; Coneski, Peter N; Schoenfisch, Mark H

    2010-12-01

    The synergistic activity between nitric oxide (NO) released from diazeniumdiolate-modified proline (PROLI/NO) and silver(I) sulfadiazine (AgSD) was evaluated against Escherichia coli, Enterococcus faecalis, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis using a modified broth microdilution technique and a checkerboard-type assay. The combination of NO and AgSD was defined as synergistic when the fractional bactericidal concentration (FBC) was calculated to be <0.5. Gram-negative species were generally more susceptible to the individual antimicrobial agents than the Gram-positive bacteria, while Gram-positive bacteria were more susceptible to combination therapy. The in vitro synergistic activity of AgSD and NO observed against a range of pathogens strongly supports future investigation of this therapeutic combination, particularly for its potential use in the treatment of burns and chronic wounds. PMID:20939612

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

    Microsoft Academic Search

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

    2000-01-01

    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

  15. Production of class II bacteriocins by lactic acid bacteria; an example of biological warfare and communication

    Microsoft Academic Search

    Vincent G. H. Eijsink; Lars Axelsson; Dzung B. Diep; Leiv S. Håvarstein; Helge Holo; Ingolf F. Nes

    2002-01-01

    Lactic acid bacteria (LAB) fight competing Gram-positive microorganisms by secreting anti-microbial peptides called bacteriocins.\\u000a Peptide bacteriocins are usually divided into lantibiotics (class I) and non-lantibiotics (class II), the latter being the\\u000a main topic of this review. During the past decade many of these bacteriocins have been isolated and characterized, and elements\\u000a of the genetic mechanisms behind bacteriocin production have been

  16. Polyamine effects on antibiotic susceptibility in bacteria.

    PubMed

    Kwon, Dong-Hyeon; Lu, Chung-Dar

    2007-06-01

    Biogenic polyamines (e.g., spermidine and spermine) are a group of essential polycationic compounds found in all living cells. The effects of spermine and spermidine on antibiotic susceptibility were examined with gram-negative Escherichia coli and Salmonella enterica serovar Typhimurium bacteria and clinical isolates of Pseudomonas aeruginosa and with gram-positive Staphylococcus aureus bacteria, including methicillin-resistant S. aureus (MRSA). Exogenous spermine exerted a dose-dependent inhibition effect on the growth of E. coli, S. enterica serovar Typhimurium, and S. aureus but not P. aeruginosa, as depicted by MIC and growth curve measurements. While the MICs of polymyxin and ciprofloxacin were in general increased by exogenous spermine and spermidine in P. aeruginosa, this adverse effect was not observed in enteric bacteria and S. aureus. It was found that spermine and spermidine can decrease the MICs of beta-lactam antibiotics in all strains as well as other types of antibiotics in a strain-dependent manner. Significantly, the MICs of oxacillin for MRSA Mu50 and N315 were decreased more than 200-fold in the presence of spermine, and this effect of spermine was retained when assessed in the presence of divalent ions (magnesium or calcium; 3 mM) or sodium chloride (150 mM). The effect of spermine on the sensitization of P. aeruginosa and MRSA to antibiotics was further demonstrated by population analysis and time-killing assays. The results of checkerboard assays with E. coli and S. aureus indicated a strong synergistic effect of spermine in combination with beta-lactams and chloramphenicol. The decreased MICs of beta-lactams implied that the possible blockage of outer membrane porins by exogenous spermine or spermidine did not play a crucial role in most cases. In contrast, only the MIC of imipenem against P. aeruginosa was increased by exogenous spermine and spermidine, and this resistance effect was abolished in a mutant strain devoid of the outer membrane porin OprD. In E. coli, the MICs of carbenicillin, chloramphenicol, and tetracycline were decreased in two acrA mutants devoid of a major efflux pump, AcrAB. However, retention of the spermine effect on antibiotic susceptibility in two acrA mutants of E. coli suggested that the AcrAB efflux pump was not the target for a synergistic effect by spermine and antibiotics and ruled out the hypothesis of spermine serving as an efflux pump inhibitor in this organism. In summary, this interesting finding of the effect of spermine on antibiotic susceptibility provides the basis for a new potential approach against drug-resistant pathogens by use of existing beta-lactam antibiotics. PMID:17438056

  17. Growth-Inhibiting and morphostructural effects of constituents identified in Asarum heterotropoides root on human intestinal bacteria

    PubMed Central

    2013-01-01

    Background The growth-inhibiting and morphostructural effects of seven constituents identified in Asarum heterotropoides root on 14 intestinal bacteria were compared with those of the fluoroquinolone antibiotic ciprofloxacin. Method A microtiter plate-based bioassay in sterile 96-well plates was used to evaluate the minimal inhibitory concentrations (MICs) of the test materials against the organisms. Results ?-3-Carene (5) exhibited the most potent growth inhibition of Gram-positive bacteria (Clostridium difficile ATCC 9689, Clostridium paraputrificum ATCC 25780, Clostridium perfringens ATCC 13124, and Staphylococcus aureus ATCC 12600) and Gram-negative bacteria (Escherichia coli ATCC 11775 and Bacteroides fragilis ATCC 25285) (minimal inhibitory concentrations (MIC), 0.18–0.70 mg/mL) except for Salmonella enterica serovar Typhimurium ATCC 13311 (MIC, 2.94 mg/mL). The MIC of methyleugenol (2), 1,8-cineole (3), ?-asarone (4), (?)-asarinin (6), and pellitorine (7) was between 1.47 and 2.94 mg/mL against all test bacteria (except for compound 2 against C. difficile (0.70 mg/mL); compounds 1 (23.50 mg/mL) and 4 (5.80 mg/mL) against C. paraputricum; compounds 2 (5.80 mg/mL), 4 (12.0 mg/mL), and 7 (0.70 mg/mL) against C. perfringens); compound 1 against E. coli (7.20 mg/mL) and S. enterica serovar Typhimurium (12.0 mg/mL). Overall, all of the constituents were less potent at inhibiting microbial growth than ciprofloxacin (MIC, 0.063–0.25 mg/ mL). The lactic acid-producing bacteria (four bifidobacteria and two lactobacilli) and one acidulating bacterium Clostridium butyricum ATCC 25779 were less sensitive and more susceptible than the five harmful bacteria and two nonpathogenic bacteria (B. fragilis and E. coli) to the constituents and to ciprofloxacin, respectively. Beneficial Gram-positive bacteria and harmful and nonpathogenic Gram-negative bacteria were observed to have different degrees of antimicrobial susceptibility to the constituents, although the antimicrobial susceptibility of the harmful Gram-positive bacteria and the harmful and nonpathogenic Gram-negative bacteria was not observed. Scanning electron microscopy observations showed different degrees of physical damage and morphological alteration to both Gram-positive and Gram-negative bacteria treated with ?-asarone, ?-3-carene, pellitorine, or ciprofloxacin, indicating that they do not share a common mode of action. Conclusion A. heterotropoides root-derived materials described merit further study as potential antibacterial products or lead molecules for the prevention or eradication from humans from diseases caused by harmful intestinal bacteria. PMID:24083511

  18. Microgravity effects on magnetotactic bacteria

    NASA Astrophysics Data System (ADS)

    Urban, James E.

    1998-01-01

    An unusual group of iron bacteria has recently been discovered which form inclusion bodies containing a form of iron oxide known as magnetite (ferrosoferric oxide, Fe3O4.) The inclusions are of a nano-particle size, are encased within a protein envelope, and are called magnetosomes. Magnetosomes are arranged adjacent to one another and parallel to the long axis of the cell such that cells appear to contain an electron-dense string of beads. The bacteria containing magnetosomes exhibit metal reductase activity, an activity critical to element recycling in nature, and the inclusions are a means for the organism to sequester reduced iron atoms and thereby keep iron reduction stoichiometry favorable. The magnetosomes also allow the bacteria to display magnetotaxis, which is movement in response to a magnetic field, such as the north or south magnetic poles. It is presumed that the bacteria use the alignment to the earth's magnetic field to orient themselves downward towards sediments where the habitat is favorable to their growth and metabolism. The comparatively few species of these bacteria isolated in the northern and southern hemispheres respond to magnetic north and south respectively, or alternatively respond only to the magnetic pole of the hemisphere from which they were isolated. This apparent dichotomy in response to magnetism could mean that the organisms are not responding to magnetism, per se, but instead are using the magnetosomes to respond to gravity. To resolve if magnetosomes respond to gravity in addition to magnetism we have used Magnetospirillum magnetotacticum, a well-studied magnetotactic bacterium isolated in the northern hemisphere, to examine magnetotactic behavior in the absence of gravity. Experiments to compare the orientation of Magnetospirillum magnetotacticum to north- or south-pole magnets were conducted in normal gravity and in the microgravity environments aboard the Space Shuttle and Space Station MIR. In each of the microgravity situations studied, bacteria were impaired in their ability to orient to magnets, suggesting that on earth the bacteria use magnetosomes to respond to gravity. These experiments could have significant commercial utility and could lead to the use of magnetosomes to direct biodegrading bacteria to contaminated aquifers or soils and likewise could be used to direct and localize bacteria used in element leaching and microbial mining.

  19. Antimicrobial Photodynamic Therapy to Kill Gram-negative Bacteria

    PubMed Central

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

    2013-01-01

    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

  20. Thermal inactivation of antimicrobial-resistant Gram-positive cocci in chicken meat: D and Z value determinations

    Microsoft Academic Search

    Dean Bertolatti; Steven J. Munyard; Warren B. Grubb; Colin W. Binns

    2001-01-01

    Antimicrobial-resistance in Gram-positive bacteria is reported with increasing frequency in strains isolated from food animals. Their isolation from commercial poultry carcasses and meat products constitute a potential risk that resistant strains or resistance genes might spread to humans via the food chain. As bacterial inactivation by thermal process is a critical control point in the safe preparation of many ready-to-eat

  1. Tunable protein degradation in bacteria

    PubMed Central

    Cameron, D. Ewen; Collins, James J.

    2014-01-01

    Tunable control of protein degradation in bacteria would provide a powerful research tool. We use components of the Mesoplasma florum tmRNA system to create a synthetic degradation system that provides both independent control of the steady-state protein level and inducible degradation of targeted proteins in Escherichia coli. We demonstrate application of this system in synthetic circuit development and control of core bacterial processes and antibacterial targets, and transfer the system to Lactococcus lactis to establish its broad functionality in bacteria. We create a 238-member library of tagged essential proteins in E. coli that can serve as both a research tool to study essential gene function and an applied system for antibiotic discovery. Our synthetic protein degradation system is modular, does not require disruption of host systems, and can be transferred to diverse bacteria with minimal modification. PMID:25402616

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

    PubMed Central

    2014-01-01

    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

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

    SciTech Connect

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

    2010-11-01

    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.

  4. In vitro growth inhibition of mastitis causing bacteria by phenolics and metal chelators

    SciTech Connect

    Chew, B.P.; Tjoelker, L.W.; Tanaka, T.S.

    1985-11-01

    Antimicrobial activities of three phenolic compounds and four metal chelators were tested at 0, 250, 500, and 1000 ppm in vitro against four major mastitis-causing bacteria, Streptococcus agalactiae, Staphylococcus aureus, Klebsiella pnuemoniae, and Escherichia coli. Overall, butylated hydroxyanisole and tert-butylhydroquinone showed the greatest antimicrobial activity. These phenolics were bactericidal at 250 to 500 ppm against all four bacteria tested. The butylated hydroxytoluene was bactericidal against the gram-positive bacteria but was ineffective against the coliforms. At 250 ppm, disodium ethylenediaminetetraacetic acid was bactericidal against the gram-positive bacteria but much less effective against the gram-negatives. However, diethylene-triaminepentaacetic acid was more growth inhibitory than ethylenediaminetetraacetic acid against the gram-negative bacteria and especially against Escherichia coli. All other compounds were generally much less effective or ineffective against all four microorganisms. Therefore, butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, ethylenediaminetetraacetic acid, and diethylenetriaminepentaacetic acid may have practical implications in the prevention or treatment of bovine mastitis.

  5. Metabolites produced by Pseudomonas sp enable a Gram-positive bacterium to achieve extracellular electron transfer

    Microsoft Academic Search

    The Hai Pham; Peter Aelterman; Peter Clauwaert; Liesje De Schamphelaire; Lynn Vanhaecke; Katrien De Maeyer; Monica Hoefte; Willy Verstraete; Korneel Rabaey

    2008-01-01

    Previous studies revealed the abundance of Pseudomonas sp. in the\\u000a microbial community of a microbial fuel cell (MFC). These bacteria can\\u000a transfer electrons to the electrode via self-produced phenazine-based\\u000a mediators. A MFC fed with acetate where several Pseudomonas sp. were\\u000a present was found to be rich in a Gram-positive bacterium, identified as\\u000a Brevibacillus sp. PTH1. Remarkably, MFCs operated with only

  6. Envisaging bacteria as phage targets

    PubMed Central

    Abedon, Stephen T.

    2011-01-01

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

  7. Observation on growth of bacteria 

    E-print Network

    Unknown

    2011-08-17

    on the underside of the seedling cotyledons (seed leaves). These areas eventu- ally dry up and die. On true leaves, the disease can form distinctive, brown, elongated lesions on and next to the veins, which also may appear water-soaked. The bacteria also pro- duce... can send tissue showing symptoms to a diagnostic laboratory, or they can use commercially avail- able diagnostic kits. Some of these kits are suitable for field use and can detect bacteria on leaf lesions before symptoms occur on fruits. These kits can...

  8. Monensin-based medium for determination of total gram-negative bacteria and Escherichia coli.

    PubMed Central

    Petzel, J P; Hartman, P A

    1985-01-01

    Plate count-monensin-KCl (PMK) agar, for enumeration of both gram-negative bacteria and Escherichia coli, is composed of (per liter) 23.5 g of plate count agar, 35 mg of monensin, 7.5 g of KCl, and 75 mg of 4-methylumbelliferyl-beta-D-glucuronide (MUG). Monensin was added after the medium was sterilized. The diluent of choice for use with PMK agar was 0.1% peptone (pH 6.8); other diluents were unsatisfactory. Gram-negative bacteria (selected for by the ionophore monensin) can be used to judge the general quality or sanitary history of a commodity. E. coli (differentiated by its ability to hydrolyze the fluorogenic compound MUG) can be used to assess the safety of a commodity in regard to the possible presence of enteric pathogens. Pure-culture studies demonstrated that monensin completely inhibited gram-positive bacteria and had little or no effect on gram-negative bacteria. When gram-negative bacteria were injured by one of several methods, a few species (including E. coli) became sensitive to monensin; this sensitivity was completely reversed in most instances by the inclusion of KCl in the medium. When PMK agar was tested with food and environmental samples, 96% of 535 isolates were gram negative; approximately 68% of colonies from nonselective medium were gram negative. PMK agar was more selective than two other media against gram-positive bacteria and was less inhibitory for gram-negative bacteria. However, with water samples, KCl had an inhibitory effect on gram-negative bacteria, and it should therefore be deleted from monensin-containing medium for water analysis.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3890742

  9. Blue Light Perception in Bacteria

    Microsoft Academic Search

    Stephan Braatsch; Gabriele Klug

    2004-01-01

    This review focuses on the blue light responses in bacteria and on the bacterial proteins which have been demonstrated to function as blue light receptors. Results of the previous years reveal that different types of photoreceptors have already evolved in prokaryotes. However, for most of these photoreceptors the exact biological functions and the mechanisms of signaling to downstream components are

  10. The sulphate-reducing bacteria

    Microsoft Academic Search

    1984-01-01

    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

  11. Swimming bacteria at complex interfaces

    NASA Astrophysics Data System (ADS)

    Lopez, Diego; Lauga, Eric

    2013-11-01

    Swimming microorganisms such as bacteria often move in confined geometries. Such confinement can be caused by the presence of solid boundaries, free surfaces, or liquid interfaces. It is well established that confinement affects significantly locomotion, generating additional forces and torques on the bacteria. In the presence of a solid boundary (imposing a no-slip condition), microorganisms using helical propulsion undergo circular motion (clockwise in the case of E. coli). Conversely, close to a free (no-shear) surface the circular motion is reversed. However, realistic interfaces are complex, and experimental results do not always agree with theoretical predictions. In this work, we show, using analytical modeling, how different complex interfaces affect a nearby bacterium and modify its swimming kinematics. Swimming microorganisms such as bacteria often move in confined geometries. Such confinement can be caused by the presence of solid boundaries, free surfaces, or liquid interfaces. It is well established that confinement affects significantly locomotion, generating additional forces and torques on the bacteria. In the presence of a solid boundary (imposing a no-slip condition), microorganisms using helical propulsion undergo circular motion (clockwise in the case of E. coli). Conversely, close to a free (no-shear) surface the circular motion is reversed. However, realistic interfaces are complex, and experimental results do not always agree with theoretical predictions. In this work, we show, using analytical modeling, how different complex interfaces affect a nearby bacterium and modify its swimming kinematics. IUSTI UMR 7343, Polytech Marseille, France.

  12. Hydrocarbon degradation by antarctic bacteria

    SciTech Connect

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

    1996-12-31

    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.

  13. Functional genomics of intracellular bacteria.

    PubMed

    de Barsy, Marie; Greub, Gilbert

    2013-07-01

    During the genomic era, a large amount of whole-genome sequences accumulated, which identified many hypothetical proteins of unknown function. Rapidly, functional genomics, which is the research domain that assign a function to a given gene product, has thus been developed. Functional genomics of intracellular pathogenic bacteria exhibit specific peculiarities due to the fastidious growth of most of these intracellular micro-organisms, due to the close interaction with the host cell, due to the risk of contamination of experiments with host cell proteins and, for some strict intracellular bacteria such as Chlamydia, due to the absence of simple genetic system to manipulate the bacterial genome. To identify virulence factors of intracellular pathogenic bacteria, functional genomics often rely on bioinformatic analyses compared with model organisms such as Escherichia coli and Bacillus subtilis. The use of heterologous expression is another common approach. Given the intracellular lifestyle and the many effectors that are used by the intracellular bacteria to corrupt host cell functions, functional genomics is also often targeting the identification of new effectors such as those of the T4SS of Brucella and Legionella. PMID:23564838

  14. Manipulating Genetic Material in Bacteria

    NASA Technical Reports Server (NTRS)

    1998-01-01

    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)

  15. Aerobic Mesophilic Bacteria in Composts

    Microsoft Academic Search

    D. M. Webley

    1948-01-01

    IN a previous communication1, an account was given of the activity of the thermophilic flora which develops in composts made from grass cuttings (lawn mowings). This thermophilic flora can be seen as a white coating on the cuttings, particularly in the upper layers during the high-temperature phase. From it true and facultative thermophilic bacteria were isolated. Recently, in addition, evidence

  16. Recognition of Bacteria by Inflammasomes

    E-print Network

    Vance,. Russell

    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

  17. Clinical Applications of Probiotic Bacteria

    Microsoft Academic Search

    S. Salminen; A. C. Ouwehand; E. Isolauri

    1998-01-01

    Probiotic bacteria are applied to balance disturbed intestinal microflora and related dysfunctions of the gastrointestinal tract. Current clinical applications include well-documented areas such as treatment of acute rotavirus diarrhoea, lactose maldigestion, constipation, colonic disorders and side-effects of pelvic radiotherapy, and more recently, food allergy including milk hypersensitivity and changes associated with colon cancer development. Many novel probiotics appear to be

  18. Zinc isotope fractionation during surface adsorption by bacteria

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

  19. Non-classical protein secretion in bacteria

    PubMed Central

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

    2005-01-01

    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

  20. Light Controllable Surface Coating for Effective Photothermal Killing of Bacteria.

    PubMed

    Kim, Sung Han; Kang, Eun Bi; Jeong, Chan Jin; Sharker, Shazid Md; In, Insik; Park, Sung Young

    2015-07-22

    Although the electronic properties of conducting films have been widely explored in optoelectronic fields, the optical absorption abilities of surface-coated films for photothermal conversion have been relatively less explored in the production of antibacterial coatings. Here, we present catechol-conjugated poly(vinylpyrrolidone) sulfobetaine (PVPS) and polyaniline (PANI) tightly linked by ionic interaction (PVPS:PANI) as a novel photothermal antibacterial agent for surface coating, which can absorb broadband near-infrared (NIR) light. Taking advantage of the NIR light absorption, this coating film can release eminent photothermal heat for the rapid killing of surface bacteria. The NIR light triggers a sharp rise in photothermal heat, providing the rapid and effective killing of 99.9% of the Gram-positive and -negative bacteria tested within 3 min of NIR light exposure when used at the concentration of 1 mg/mL. Although considerable progress has been made in the design of antibacterial coatings, the user control of NIR-irradiated rapid photothermal destruction of surface bacteria holds increasing attention beyond the traditional boundaries of typical antibacterial surfaces. PMID:26101891

  1. Pectin-fermenting Bacteria Isolated from the Bovine Rumen1

    PubMed Central

    Dehority, B. A.

    1969-01-01

    Thirty-two strains of pectin-fermenting rumen bacteria were isolated from bovine rumen contents in a rumen fluid medium which contained pectin as the only added energy source. Based on differences in morphology and the Gram stain, 10 of these strains were selected for characterization. Two strains were identified as Lachnospira multiparus, four strains were identified as Butyrivbrio fibrisolvens, and three strains were identified as Bacteroides ruminicola. Characteristics of the remaining strain did not correspond with any previously described species. It was a gram-positive anaerobic coccus, 1.0 to 1.2 ?m in diameter, and occurred primarily as single cells or diplococci. The strain fermented pectin rapidly but showed little or no growth on any other energy sources tested. The only detectable end products were acetic acid and gas, a portion of which was identified as hydrogen. Although the physiological characteristics of this organism differ markedly from other described species, it has been placed in the genus Peptostreptococcus on the basis of morphology, Gram stain, relations to oxygen, and the occurrence of cell division in only one plane. End products of fermentation are somewhat similar to those of the cellulolytic ruminococci. Eight previously characterized strains of cellulolytic bacteria isolated in nonselective media were unable to ferment pectin, whereas ten strains of hemicellulolytic rumen bacteria, eight of which were isolated with a xylan medium, showed considerable variation in this characteristic. Images PMID:5802604

  2. Surface-enhanced Raman spectroscopy of bacteria coated by silver

    NASA Astrophysics Data System (ADS)

    Efrima, Schlomo; Bronk, Burt V.; Czege, Jozsef

    1999-05-01

    We present a novel method to measure Raman spectra from whole bacteria cells by using Surface Enhanced Raman Scattering (SERS). We deposit a silver coat on Escherichia coli and Bacillus megaterium bacteria and measure strongly enhanced (greater than 400,000 fold) and highly reproducible Raman spectra. The spectra are rich but not overly congested, as the surface enhancement is selective to the precise chemical nature of the biochemical molecules, and their proximity to the silver particulate matter. The main bands we observe can be associated with peptides and polysaccharides in the cell- wall and its membrane. The spectra from E. coli (a Gram- negative bacterium) and B. megaterium (a Gram-positive bacterium) are similar in their general form, but differ in detail. The spectrum from a commercial yeast extract is vastly different. This approach can be extended to probe the internal chemical environment within bacteria and applied to the identification of micro-organisms also applied to studying other biochemical problems and phenomena, such as biomineralization, heavy metal toxicity, cell-wall structure and others.

  3. Americans' Gut Bacteria Lack Diversity, Researchers Find

    MedlinePLUS

    ... gov/medlineplus/news/fullstory_152064.html Americans' Gut Bacteria Lack Diversity, Researchers Find People living in less- ... Papua New Guinea have 50 more types of bacteria To use the sharing features on this page, ...

  4. 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 ...

  5. Bacteria, Yeast and Chemicals on Human Skin

    MedlinePLUS

    ... gov/medlineplus/videos/news/Microbes_040115-1.html Bacteria, Yeast and Chemicals on Human Skin HealthDay News ... on this page, please enable JavaScript. Play video: Bacteria, Yeast and Chemicals on Human Skin For closed ...

  6. Killer Pigments in Bacteria: An Ecological Nightmare.

    ERIC Educational Resources Information Center

    Benathen, Isaiah A.; Saccardi, Marion

    2000-01-01

    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)

  7. Re-engineering bacteria for ethanol production

    SciTech Connect

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

    2014-05-06

    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.

  8. Structure of homoserine O-acetyltransferase from Staphylococcus aureus: the first Gram-positive ortholog structure.

    PubMed

    Thangavelu, Bharani; Pavlovsky, Alexander G; Viola, Ronald

    2014-10-01

    Homoserine O-acetyltransferase (HTA) catalyzes the formation of L-O-acetyl-homoserine from L-homoserine through the transfer of an acetyl group from acetyl-CoA. This is the first committed step required for the biosynthesis of methionine in many fungi, Gram-positive bacteria and some Gram-negative bacteria. The structure of HTA from Staphylococcus aureus (SaHTA) has been determined to a resolution of 2.45?Å. The structure belongs to the ?/?-hydrolase superfamily, consisting of two distinct domains: a core ?/?-domain containing the catalytic site and a lid domain assembled into a helical bundle. The active site consists of a classical catalytic triad located at the end of a deep tunnel. Structure analysis revealed some important differences for SaHTA compared with the few known structures of HTA. PMID:25286936

  9. Modulation of pulmonary clearance of bacteria by antioxidants.

    PubMed Central

    Pesanti, E L; Nugent, K M

    1985-01-01

    To further delineate the mechanisms underlying murine pulmonary defenses against bacterial infection, we studied the effects of antioxidant enzymes and hydroxyl radical scavengers on pulmonary clearance processes. Intratracheal injection of catalase and superoxide dismutase resulted in prolonged intraalveolar residence of the enzymes, but caused no decrease in rates of clearance of either Staphylococcus aureus 502A or Pseudomonas aeruginosa PAO1. In contrast, dimethylsulfoxide and dimethylthiourea caused significant depression of clearance of P. aeruginosa without altering clearance of S. aureus. These results provide further differentiation between clearance processes affecting gram-negative and gram-positive bacteria and suggest that murine clearance of gram-negative organisms may be in part mediated by reactions which generate hydroxyl anion. In vivo administration of agents which inhibit hydrogen peroxide-, superoxide-, or hydroxyl anion-mediated reactions do not alter normal clearance of S. aureus. PMID:3980094

  10. Antagonism of Lactic Acid Bacteria against Phytopathogenic Bacteria

    PubMed Central

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

    1986-01-01

    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

  11. 3, 765778, 2006 Culturable bacteria in

    E-print Network

    Boyer, Edmond

    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

  12. Drosophila lifespan enhancement by exogenous bacteria

    E-print Network

    Seroude, Laurent

    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

  13. 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

  14. Laser-Based Identification of Pathogenic Bacteria

    ERIC Educational Resources Information Center

    Rehse, Steven J.

    2009-01-01

    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…

  15. Diversity of endophytic bacteria in Brazilian sugarcane

    Microsoft Academic Search

    G. S. Magnani; C. M. Didonet; L. M. Cruz; C. F. Picheth; F. O. Pedrosa; E. M. Souza

    2010-01-01

    Endophytic bacteria live inside plant tissues without caus- ing disease. Studies of endophytes in sugarcane have focused on the iso- lation of diazotrophic bacteria. We examined the diversity of endophytic bacteria in the internal tissues of sugarcane stems and leaves, using mo- lecular and biochemical methods. Potato-agar medium was used to cul- tivate the endophytes; 32 isolates were selected for

  16. Sequencing and Characterization of the xyl Operon of a Gram-Positive Bacterium, Tetragenococcus halophila

    PubMed Central

    Takeda, Yasuo; Takase, Kazuma; Yamato, Ichiro; Abe, Keietsu

    1998-01-01

    The xyl operon of a gram-positive bacterium, Tetragenococcus halophila (previously called Pediococcus halophilus), was cloned and sequenced. The DNA was about 7.7 kb long and contained genes for a ribose binding protein and part of a ribose transporter, xylR (a putative regulatory gene), and the xyl operon, along with its regulatory region and transcription termination signal, in this order. The DNA was AT rich, the GC content being 35.8%, consistent with the GC content of this gram-positive bacterium. The xyl operon consisted of three genes, xylA, encoding a xylose isomerase, xylB, encoding a xylulose kinase, and xylE, encoding a xylose transporter, with predicted molecular weights of 49,400, 56,400, and 51,600, respectively. The deduced amino acid sequences of the XylR, XylA, XylB, and XylE proteins were similar to those of the corresponding proteins in other gram-positive and -negative bacteria, the similarities being 37 to 64%. Each polypeptide of XylB and XylE was expressed functionally in Escherichia coli. XylE transported d-xylose in a sodium ion-dependent manner, suggesting that it is the first described xylose/Na+ symporter. The XylR protein contained a consensus sequence for binding catabolites of glucose, such as glucose-6-phosphate, which has been discovered in glucose and fructose kinases in bacteria. Correspondingly, the regulatory region of this operon contained a putative binding site of XylR with a palindromic structure. Furthermore, it contained a consensus sequence, CRE (catabolite-responsive element), for binding CcpA (catabolite control protein A). We speculate that the transcriptional regulation of this operon resembles the regulation of catabolite-repressible operons such as the amy, lev, xyl, and gnt operons in various gram-positive bacteria. We discuss the significance of the regulation of gene expression of this operon in T. halophila. PMID:9647823

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

    PubMed Central

    2012-01-01

    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

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

    PubMed

    Pophaly, Sarang Dilip; Singh, Rameshwar; Pophaly, Saurabh Dilip; Kaushik, Jai K; Tomar, Sudhir Kumar

    2012-01-01

    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

  19. Recent developments in understanding the iron acquisition strategies of gram positive pathogens.

    PubMed

    Sheldon, Jessica R; Heinrichs, David E

    2015-07-01

    Iron is a versatile redox-active catalyst and a required cofactor within a diverse array of biological processes. To almost all organisms, iron is both essential and potentially toxic, where homeostatic concentrations must be stringently maintained. Within the iron-restricted host, the survival and proliferation of microbial invaders is contingent upon exploiting the host iron pool. Bacteria express a multitude of complex, and often redundant means of acquiring iron, including surface-associated heme-uptake pathways, high affinity iron-scavenging siderophores and transporters of free inorganic iron. Within the last decade, our understanding of iron acquisition by Gram-positive pathogens has expanded substantively, from the discovery of the iron-regulated surface-determinant pathway and numerous unique siderophores through to the detailed elucidation of heme-iron extraction, and heme and siderophore coordination and transfer. This review provides a comprehensive summary of the iron acquisition strategies of notorious Gram-positive pathogens and highlights how both conserved and distinct tactics for acquiring iron contribute to the pathophysiology of these bacteria. Further, a focus on recent structural and mechanistic studies details how these iron acquisition systems may be exploited in the development of novel therapeutics. PMID:25862688

  20. Swimming bacteria power microscopic gears.

    SciTech Connect

    Sokolov, A.; Apodaca, M. M.; Grzybowski, B. A.; Aranson, I. S.; Materials Science Division; Princeton Univ.; Northwestern Univ.

    2010-01-19

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be 'rectified' under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms.

  1. Swimming bacteria power microscopic gears

    SciTech Connect

    Sokolov, Andrey; Apodaca, Mario M.; Grzybowski, Bartosz A.; Aranson, Igor S.

    2010-01-01

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be “rectified” under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears’ angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms.

  2. Protein signaling via type III secretion pathways in phytopathogenic bacteria

    E-print Network

    Mudgettt, Mary Beth

    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

  3. Telavancin: an antimicrobial with a multifunctional mechanism of action for the treatment of serious gram-positive infections.

    PubMed

    Leonard, Steven N; Rybak, Michael J

    2008-04-01

    Telavancin is a once-daily lipoglycopeptide antibiotic structurally derived from vancomycin. It has broad-spectrum activity against gram-positive bacteria, including strains with reduced susceptibility to vancomycin. Telavancin's multifunctional mechanism of action, including inhibition of peptidoglycan synthesis and disruption of membrane potential, account for this enhanced activity as well as rapid bactericidal properties. In vitro activity has been demonstrated against a wide range of gram-positive pathogens such as multidrug-resistant Streptococcus pneumoniae, as well as methicillin-resistant, glycopeptide-intermediate, and vancomycin-resistant Staphylococcus aureus. The agent also displays activity against many gram-positive anaerobic organisms. Predictable linear pharmacokinetics have been demonstrated over a wide range of doses, with the most common adverse effects being taste disturbance and nausea. Clinical experience with telavancin in phase II and III studies for complicated skin and skin structure infections has shown it to have similar efficacy and tolerability compared with vancomycin and antistaphylococcal penicillins, and recently telavancin received an approvable letter from the United States Food and Drug Administration for this indication. Telavancin appears to be a promising agent for the treatment of serious infections caused by gram-positive pathogens, including drug-resistant pathogens. Further clinical experience will clarify its role in therapy. PMID:18363530

  4. Genetics of Lactic Acid Bacteria

    Microsoft Academic Search

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

    2008-01-01

    Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally\\u000a contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation\\u000a of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer\\u000a addition of

  5. Bacteria Allocation Using Monte Carlo

    NSDL National Science Digital Library

    Hill, David R.

    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.

  6. Anaerobic bacteria from hypersaline environments.

    PubMed Central

    Ollivier, B; Caumette, P; Garcia, J L; Mah, R A

    1994-01-01

    Strictly anaerobic halophiles, namely fermentative, sulfate-reducing, homoacetogenic, phototrophic, and methanogenic bacteria are involved in the oxidation of organic carbon in hypersaline environments. To date, six anaerobic fermentative genera, containing nine species, have been described. Two of them are homoacetogens. Six species belong to the family Haloanaerobiaceae, as indicated by their unique 16S rRNA oligonucleotide sequences. Desulfohalobium retbaense and Desulfovibrio halophilus represent the only two moderately halophilic sulfate reducers so far reported. Among anoxygenic phototrophic anaerobes, a few purple bacteria with optimal growth at salinities between 6 and 11% NaCl have been isolated from hypersaline habitats. They belong to the genera Rhodospirillum, Chromatium, Thiocapsa, and Ectothiorhodospira. The commonest organisms isolated so far are Chromatium salexigens, Thiocapsa halophila, and Rhodospirillum salinarum. Extremely halophilic purple bacteria have most commonly been isolated from alkaline brines and require about 20 to 25% NaCl for optimal growth. They belong to the family Ectothiorodhospiraceae. Their osmoregulation involves synthesis or uptake of compatible solutes such as glycine-betaine that accumulate in their cytoplasm. The existence of methanogens in hypersaline environments is related to the presence of noncompetitive substrates such as methylamines, which originate mainly from the breakdown of osmoregulatory amines. Methanogenesis probably does not contribute to the mineralization of carbohydrates at NaCl concentrations higher than 15%. Above this concentration, sulfate reduction is probably the main way to oxidize H2 (although at rates too low to use up all the H2 formed) and occupies a terminal function kn the degradation of carbohydrates. Three genera and five species of halophilic methylotrophic methanogens have been reported. A bloom of phototrophic bacteria in the marine salterns of Salins-de-Giraud, located on the Mediterranean French coast in the Rhone Delta, is also described. PMID:8177169

  7. Bacteria turn a tiny gear

    SciTech Connect

    None

    2009-01-01

    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.

  8. Transposon mutagenesis of coryneform bacteria

    Microsoft Academic Search

    Alain A. Vertès; Yoko Asai; Masayuki Inui; Miki Kobayashi; Yasurou Kurusu; Hideaki Yukawa

    1994-01-01

    The Corynebacterium glutamicum insertion sequence IS31831 was used to construct two artificial transposons: Tn31831 and miniTn31831. The transposition vectors were based on a gram-negative replication origin and do not replicate in coryneform bacteria. Strain Brevibacterium flavum MJ233C was mutagenized by miniTn31831 at an efficiency of 4.3 x 104 mutants per microgram DNA. Transposon insertions occurred at different locations on the

  9. Dispersal dynamics of groundwater bacteria

    Microsoft Academic Search

    Roland Lindqvist; Göran Bengtsson

    1991-01-01

    Dispersal of bacteria in saturated, porous soils can be characterized by the partitioning of cells between the aqueous and\\u000a solid phases, as a result of the physical and chemical nature of the soil and water and cell surface modifications. The purpose\\u000a of this work is to understand variations in partitioning as a consequence of the nutrient conditions and to use

  10. 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...

  11. Chemical signature of magnetotactic bacteria.

    PubMed

    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

    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

  12. Characterization of Mediterranean magnetotactic bacteria

    NASA Astrophysics Data System (ADS)

    Lefèvre, Christopher; Bernadac, Alain; Pradel, Nathalie; Wu, Longfei; Yu-Zhang, Kui; Xiao, Tian; Yonnet, Jean-Paul; Lebouc, Afef; Song, Tao; Fukumori, Yoshihiro

    2007-10-01

    Magnetotactic bacteria are a diverse group of motile prokaryotes that are ubiquitous in aquatic habitats and cosmopolitan in distribution. In this study, we collected magnetotactic bacteria from the Mediterranean Sea. A remarkable diversity of morphotypes was observed, including multicellular types that seemed to differ from those previously found in North and South America. Another interesting organism was one with magnetosomes arranged in a six-stranded bundle which occupied one third of the cell width. The magnetosome bundle was evident even under optic microscopy. These cells were connected together and swam as a linear entire unit. Magnetosomes did not always align up to form a straight linear chain. A chain composed of rectangle magnetosomes bent at a position with an oval crystal. High resolution transmission electron microscopy analysis of the crystal at the pivotal position suggested uncompleted formation of the crystal. This is the first report of Mediterranean magnetotactic bacteria, which should be useful for studies of biogeochemical cycling and geohistory of the Mediterranean Sea.

  13. Anti-Peptidoglycan Antibodies and Fc? Receptors Are the Key Mediators of Inflammation in Gram-Positive Sepsis

    PubMed Central

    Sun, Dawei; Raisley, Brent; Langer, Marybeth; Iyer, Janaki K.; Vedham, Vidya; Ballard, Jimmy L.; James, Judith A.; Metcalf, Jordan

    2012-01-01

    Gram-positive bacteria are an important public health problem, but it is unclear how they cause systemic inflammation in sepsis. Our previous work showed that peptidoglycan (PGN) induced proinflammatory cytokines in human cells by binding to an unknown extracellular receptor, followed by phagocytosis leading to the generation of NOD ligands. In this study, we used flow cytometry to identify host factors that supported PGN binding to immune cells. PGN binding required plasma, and plasma from all tested healthy donors contained IgG recognizing PGN. Plasma depleted of IgG or of anti-PGN Abs did not support PGN binding or PGN-triggered cytokine production. Adding back intact but not F(ab?)2 IgG restored binding and cytokine production. Transfection of HEK293 cells with Fc?RIIA enabled PGN binding and phagocytosis. These data establish a key role for anti-PGN IgG and Fc?Rs in supporting inflammation to a major structural element of Gram-positive bacteria and suggest that anti-PGN IgG contributes to human pathology in Gram-positive sepsis. PMID:22815288

  14. AIDS: "it's the bacteria, stupid!".

    PubMed

    Broxmeyer, Lawrence; Cantwell, Alan

    2008-11-01

    Acid-fast tuberculous mycobacterial infections are common in AIDS and are regarded as secondary "opportunistic infections." According to the National Institute of Allergy and Infectious Diseases, TB is the major attributable cause of death in AIDS patients. Could such bacteria play a primary or causative role in AIDS? Certainly, In screening tests for HIV, there is frequent, up to 70%, cross-reactivity, between the gag and pol proteins of HIV and patients with mycobacterial infections such as tuberculosis. By 1972, five years before gays started dying in the U.S., Rolland wrote Genital Tuberculosis, a Forgotten Disease? And ironically, in 1979, on the eve of AIDS recognition, Gondzik and Jasiewicz showed that even in the laboratory, genitally infected tubercular male guinea pigs could infect healthy females through their semen by an HIV-compatible ratio of 1 in 6 or 17%, prompting him to warn his patients that not only was tuberculosis a sexually transmitted disease, but also the necessity of the application of suitable contraceptives, such as condoms, to avoid it. Gondzik's solution and date of publication are chilling; his findings significant. Since 1982 Cantwell et al found acid-fast bacteria closely related to tuberculosis (TB) and atypical tuberculosis in AIDS tissue. On the other hand molecular biologist and virologist Duesberg, who originally defined retroviral ultrastructure, has made it clear that HIV is not the cause of AIDS and that the so-called AIDS retrovirus has never been isolated in its pure state. Dr. Etienne de Harven, first to examine retroviruses under the electron, agrees. In 1993 HIV co-discoverer Luc Montagnier reported on cell-wall-deficient (CWD) bacteria which he called "mycoplasma" in AIDS tissue. He suspected these as a necessary "co-factor" for AIDS. Remarkably, Montagnier remained silent on Cantwell's reports of acid-fast bacteria which could simulate "mycoplasma" in AIDS tissue. Mattman makes clear that the differentiation between mycoplasma and CWD bacteria is difficult at best and cites Pachas's 1985 study wherein one mycoplasma was actually mistaken for a CWD form of a bacterium closely related to the mycobacteria. It is important to realize that the statement "HIV is the sole cause of AIDS" is just a hypothesis. There are unanswered questions and controversy concerning the role of HIV "as the sole cause of AIDS." And until they are resolved, a cure is not possible. This paper explores the possible role of acid-fast tuberculous mycobacteria as "primary agents" in AIDS. PMID:18691828

  15. Type IV pili-related natural transformation systems: DNA transport in mesophilic and thermophilic bacteria.

    PubMed

    Averhoff, Beate; Friedrich, Alexandra

    2003-12-01

    Horizontal gene flow is a driving force for bacterial adaptation. Among the three distinct mechanisms of gene transfer in bacteria, conjugation, transduction, and transformation, the latter, which includes competence induction, DNA binding, and DNA uptake, is perhaps the most versatile mechanism and allows the incorporation of free DNA from diverse bacterial species. Here we review DNA transport machineries mediating uptake of naked DNA in gram-positive and gram-negative bacteria. Different putative models of transformation machineries comprising components similar to proteins of type IV pili are presented. Emphasis is placed on a comparative discussion of the underlying mechanisms of DNA transfer in mesophilic and extremely thermophilic bacteria, highlighting conserved and distinctive features of these transformation machineries. PMID:14593449

  16. In Vitro Activities of Linezolid against Important Gram-Positive Bacterial Pathogens Including Vancomycin-Resistant Enterococci

    PubMed Central

    Noskin, Gary A.; Siddiqui, Farida; Stosor, Valentina; Hacek, Donna; Peterson, Lance R.

    1999-01-01

    The emergence of resistance in gram-positive bacteria has necessitated a search for new antimicrobial agents. Linezolid is an oxazolidinone, a new class of antibacterial agents with enhanced activity against pathogens. We compared the activity of linezolid to those of other antimicrobial agents against 3,945 clinical isolates. Linezolid demonstrated potent activity against all isolates tested. For all vancomycin-susceptible enterococci, staphylococci, and streptococci, the activity of linezolid was comparable to that of vancomycin. Against oxacillin-resistant staphylococci and vancomycin-resistant enterococci, linezolid was the most active agent tested. In summary, linezolid appears to be a promising new antimicrobial agent for the treatment of gram-positive infections. PMID:10428937

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

    Microsoft Academic Search

    Saïd Ennahar; Yimin Cai; Yasuhito Fujita

    2003-01-01

    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

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

    PubMed

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

    2008-12-01

    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

  19. Superoxide dismutase in anaerobic bacteria of clinical significance.

    PubMed

    Tally, F P; Goldin, B R; Jacobus, N V; Gorbach, S L

    1977-04-01

    Twenty-two anaerobic bacteria isolated from infected sites and normal fecal flora were assayed for superoxide dismutase (SOD). The organisms were also classified according to their oxygen tolerance into aerotolerant, intermediate, and extremely oxygen-sensitive groups. There was a correlation between the enzyme level and the oxygen tolerance, in that the aerotolerant and intermediate organisms had SOD, whereas the extremely oxygen-sensitive isolates had low or undetectable enzyme. Among the oxygen-tolerant organisms, gram-negative bacteria had higher levels of SOD than gram-positive organisms. Oxygen was shown to induce SOD production in a strain of Bacteriodes fragilis grown in minimal medium under continuous-culture conditions. Enzyme levels in this isolate grown under static conditions were lower in minimal medium than in complex medium, indicating that other components in the complex medium were stimulating the production of SOD. Our data suggest that the variation in oxygen tolerance of anaerobes is usually related to their level of SOD. It is postulated that SOD may be a virulence factor that allows pathogenic anaerobes to survive in oxygenated tissues until the proper reduced conditions are established for their growth. PMID:326669

  20. Antagonistic activity against pathogenic bacteria by human vaginal lactobacilli.

    PubMed

    Voravuthikunchai, Supayang Piyawan; Bilasoi, Sopa; Supamala, Orawan

    2006-01-01

    This study attempted to isolate lactobacilli strains from healthy vaginal ecosystem to search for a new effective antibacterial probiotic strain. The strains were identified and characterized for their probiotic properties including bile salt and acid tolerance, growth at acidic pH, their ability to utilize protein, starch, and lipid, the production of hydrogen peroxide and bacteriocin as well as their antibiotic resistance patterns. The antibacterial activity of the culture supernatant of these strains were tested against a wide range of Gram-positive and Gram-negative pathogenic bacteria including Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae. Salmonella typhi, and Salmonella typhimurium. None of the strains inhibited the growth of Gram-negative bacteria. Contrastly, the culture supernatant of strain L 22, identified as Lactobacillus reuteri, significantly inhibited all of the clinical isolates of methicillin-resistant S. aureus (MRSA). The antibacterial effect of the selected strain L 22 was further investigated. In the presence of L 22, the bacterial growth was assessed in vitro by viable bacterial counting. The numbers of viable cells were significantly lower in L 22-containing broth than those in the control by 6h. This finding clearly demonstrates that strain L 22 can produce an anti-MRSA effect. The antibacterial ability of the strain L 22 was fundamentally attributed to their bacteriocin production which can cause both cell inhibition and cell death. PMID:16931064

  1. Lactic acid bacteria convert human fibroblasts to multipotent cells.

    PubMed

    Ohta, Kunimasa; Kawano, Rie; Ito, Naofumi

    2012-01-01

    The human gastrointestinal tract is colonized by a vast community of symbionts and commensals. Lactic acid bacteria (LAB) form a group of related, low-GC-content, gram-positive bacteria that are considered to offer a number of probiotic benefits to general health. While the role of LAB in gastrointestinal microecology has been the subject of extensive study, little is known about how commensal prokaryotic organisms directly influence eukaryotic cells. Here, we demonstrate the generation of multipotential cells from adult human dermal fibroblast cells by incorporating LAB. LAB-incorporated cell clusters are similar to embryoid bodies derived from embryonic stem cells and can differentiate into endodermal, mesodermal, and ectodermal cells in vivo and in vitro. LAB-incorporated cell clusters express a set of genes associated with multipotency, and microarray analysis indicates a remarkable increase of NANOG, a multipotency marker, and a notable decrease in HOX gene expression in LAB-incorporated cells. During the cell culture, the LAB-incorporated cell clusters stop cell division and start to express early senescence markers without cell death. Thus, LAB-incorporated cell clusters have potentially wide-ranging implications for cell generation, reprogramming, and cell-based therapy. PMID:23300571

  2. In vitro activity of Bay Y3118 against anaerobic bacteria.

    PubMed Central

    Wexler, H M; Molitoris, E; Finegold, S M

    1993-01-01

    The antimicrobial activity of a new quinolone, Bay Y3118, was determined against 326 strains of anaerobic bacteria and compared with the activities of ampicillin-sulbactam, cefotetan, clindamycin, imipenem, metronidazole, and sparfloxacin. The National Committee for Clinical Laboratory Standards-approved Wadsworth agar dilution technique with Brucella-laked blood agar was used throughout the study. Breakpoints used to determine the percent susceptible were 2 micrograms/ml for Bay Y3118 and sparfloxacin, 4 micrograms/ml for clindamycin, 8 micrograms/ml for imipenem, 16 micrograms/ml for metronidazole and ampicillin-sulbactam, and 32 micrograms/ml for cefotetan. Species tested included Bacteroides fragilis (57 strains), other B. fragilis group species (79 strains), Bacteroides gracilis (10 strains), other Bacteroides spp. (9 strains), Prevotella spp. (30 strains), Porphyromonas spp. (9 strains), Fusobacterium spp. (36 strains), Bilophila wadsworthia (14 strains), Clostridium spp. (36 strains), Peptostreptococcus spp. (20 strains), and gram-positive non-spore-forming rods (26 strains). Bay Y3118 inhibited all but 1 of 326 anaerobic bacteria tested at the breakpoint level or lower. PMID:8285647

  3. Crystal structure of a DNA polymerase sliding clamp from a Gram-positive bacterium

    PubMed Central

    Argiriadi, Maria A; Goedken, Eric R; Bruck, Irina; O'Donnell, Mike; Kuriyan, John

    2006-01-01

    Background Sliding DNA clamps are processivity factors that are required for efficient DNA replication. DNA polymerases maintain proximity to nucleic acid templates by interacting with sliding clamps that encircle DNA and thereby link the polymerase enzyme to the DNA substrate. Although the structures of sliding clamps from Gram-negative bacteria (E. coli), eukaryotes, archaea, and T4-like bacteriophages are well-known, the structure of a sliding clamp from Gram-positive bacteria has not been reported previously. Results We have determined the crystal structure of the dimeric ? subunit of the DNA polymerase III holoenzyme of Streptococcus pyogenes. The sliding clamp from this Gram-positive organism forms a ring-shaped dimeric assembly that is similar in overall structure to that of the sliding clamps from Gram-negative bacteria, bacteriophage T4, eukaryotes and archaea. The dimer has overall dimensions of ~90 Å × ~70 Å × ~25 Å with a central chamber that is large enough to accommodate duplex DNA. In comparison to the circular shape of other assemblies, the S. pyogenes clamp adopts a more elliptical structure. Conclusion The sequences of sliding clamps from S. pyogenes and E. coli are only 23% identical, making the generation of structural models for the S. pyogenes clamp difficult in the absence of direct experimental information. Our structure of the S. pyogenes ? subunit completes the catalog of clamp structures from all the major sequence grouping of sliding clamps. The more elliptical rather than circular structure of the S. pyogenes clamp implies that the topological nature of encircling DNA, rather than a precise geometric shape, is the most conserved aspect for this family of proteins. PMID:16403212

  4. Medicinal smoke reduces airborne bacteria.

    PubMed

    Nautiyal, Chandra Shekhar; Chauhan, Puneet Singh; Nene, Yeshwant Laxman

    2007-12-01

    This study represents a comprehensive analysis and scientific validation of our ancient knowledge about the effect of ethnopharmacological aspects of natural products' smoke for therapy and health care on airborne bacterial composition and dynamics, using the Biolog microplate panels and Microlog database. We have observed that 1h treatment of medicinal smoke emanated by burning wood and a mixture of odoriferous and medicinal herbs (havan sámagri=material used in oblation to fire all over India), on aerial bacterial population caused over 94% reduction of bacterial counts by 60 min and the ability of the smoke to purify or disinfect the air and to make the environment cleaner was maintained up to 24h in the closed room. Absence of pathogenic bacteria Corynebacterium urealyticum, Curtobacterium flaccumfaciens, Enterobacter aerogenes (Klebsiella mobilis), Kocuria rosea, Pseudomonas syringae pv. persicae, Staphylococcus lentus, and Xanthomonas campestris pv. tardicrescens in the open room even after 30 days is indicative of the bactericidal potential of the medicinal smoke treatment. We have demonstrated that using medicinal smoke it is possible to completely eliminate diverse plant and human pathogenic bacteria of the air within confined space. PMID:17913417

  5. Methanotrophic Bacteria: Use in Bioremediation

    SciTech Connect

    Brigmon, R.L.

    2001-02-15

    The methanotrophs are aerobic bacteria that oxidize methane as an energy source and carbon source through the enzyme methane monooxygenase (MMO). This MMO can cometabolize or transform nongrowth substrates by either growing or resting cells. Cometabolism is a result of nonspecific MMO activity towards organic compounds that do not serve as carbon or energy sources. While many cometabolizing bacterial species have been identified, the best studied are the methanotrophs. The reason for this is that methanotrophs are ubiquitous and can cometabolize many aliphatic compounds, alkanes, and aromatic compounds. Methanotrophs have been intensely studied for use in degrading chlorinated solvents, most notably trichloroethylene, to environmentally acceptable concentrations in soils, sediment, and groundwater. Stimulation of methanotrophic bacteria is accomplished through the addition of methane and other gaseous nutrients resulting in an increase in contaminant biodegradation and biotransformation. The composition of gaseous nutrients used with methane is dependent on the characteristics of the site geochemistry and microbiology. This biostimulation may be applied in situ within the contaminated aquifer or soil. If necessary, the contaminated soil or groundwater can be moved and treated ex situ based on the site-specific needs.

  6. 5, 317359, 2008 Bacteria dynamics in

    E-print Network

    Paris-Sud XI, Université de

    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

  7. Antibiotic Resistance in Oral\\/Respiratory Bacteria

    Microsoft Academic Search

    M. C. Roberts

    1998-01-01

    In the last 20 years, changes in world technology have occurred which have allowed for the rapid transport of people, food, and goods. Unfortunately, antibiotic residues and antibiotic-resistant bacteria have been transported as well. Over the past 20 years, the rise in antibiotic-resistant gene carriage in virtually every species of bacteria, not just oral\\/respiratory bacteria, has been documented. In this

  8. Novel Antimicrobial Peptides That Inhibit Gram Positive Bacterial Exotoxin Synthesis

    PubMed Central

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

    2014-01-01

    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

  9. Essential genes from Arctic bacteria used to construct stable, temperature-sensitive bacterial vaccines

    PubMed Central

    Duplantis, Barry N.; Osusky, Milan; Schmerk, Crystal L.; Ross, Darrell R.; Bosio, Catharine M.; Nano, Francis E.

    2010-01-01

    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

  10. Enzymatic modification of regenerated cellulosic fabrics to improve bacteria sorption properties.

    PubMed

    Akbari, M; Dadadashian, F; Kordestani, S S; Xue, M; Jackson, C J

    2013-06-01

    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

  11. Common Virulence Factors and Tissue Targets of Entomopathogenic Bacteria for Biological Control of Lepidopteran Pests

    PubMed Central

    Castagnola, Anaïs; Stock, S. Patricia

    2014-01-01

    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

  12. Motility of flagellated bacteria in viscous environments.

    PubMed Central

    Greenberg, E P; Canale-Parola, E

    1977-01-01

    The lowest viscosity that immobilized flagellated bacteria such as Psedomonas aeruginosa, Spirillum serpens, and Escherichia coli was 60 centipoise (cp). Much higher viscosities (1,000 cp and higher) were required to immobilize two flagellated bacteria selectively isolated from nature by methods based on their ability to migrate through agar gels. The latter finding indicates that certain flagellated bacteria have the ability to swim through environments of relatively high viscosity. It is suggested that these flagellated bacteria possess a specialized type of motility apparatus suited to viscous conditions present in their habitats. PMID:410784

  13. Generating and Exploiting Polarity in Bacteria

    NSDL National Science Digital Library

    Lucy Shapiro (Stanford University School of Medicine; Department of Developmental Biology)

    2002-12-06

    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.

  14. Spectroscopic diagnostics for bacteria in biologic sample

    DOEpatents

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

    2002-01-01

    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.

  15. Managing Bacteria Pollution in Texas Waters 

    E-print Network

    Wythe, Kathy

    2007-01-01

    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...

  16. Peptide-bacteria interactions using engineered surface-immobilized peptides from class IIa bacteriocins.

    PubMed

    Etayash, Hashem; Norman, Lana; Thundat, Thomas; Kaur, Kamaljit

    2013-03-26

    Specificity of the class IIa bacteriocin Leucocin A (LeuA), an antimicrobial peptide active against Gram-positive bacteria, including Listeria monocytogenes , is known to be dictated by the C-terminal amphipathic helical region, including the extended hairpin-like structure. However, its specificity when attached to a substrate has not been investigated. Exploiting properties of LeuA, we have synthesized two LeuA derivatives, which span the amphipathic helical region of the wild-type LeuA, consisting of 14- (14AA LeuA, CWGEAFSAGVHRLA) and 24-amino acid residues (24AA LeuA, CSVNWGEAFSAGVHRLANGGNGFW). The peptides were purified to >95% purity, as shown by analytical RP-HPLC and mass spectrometry. By including an N-terminal cysteine group, the tailored peptide fragments were readily immobilized at the gold interfaces. The resulting thickness and molecular orientation, determined by ellipsometry and grazing angle infrared spectroscopy, respectively, indicated that the peptides were covalently immobilized in a random helical orientation. The bacterial specificity of the anchored peptide fragments was tested against Gram-positive and Gram-negative bacteria. Our results showed that the adsorbed 14AA LeuA exhibited no specificity toward the bacterial strains, whereas the surface-immobilized 24AA LeuA displayed significant binding toward Gram-positive bacteria with various binding affinities from one strain to another. The 14AA LeuA did not show binding as this fragment is most likely too short in length for recognition by the membrane-bound receptor on the target bacterial cell membrane. These results support the potential use of class IIa bacteriocins as molecular recognition elements in biosensing platforms. PMID:23445325

  17. Beating bacteria: Scientists work to understand and track bacteria in water 

    E-print Network

    Wythe, Kathy

    2010-01-01

    tx H2O | pg. 11 Story by Kathy Wythe Bacteria Task Force Recommendations Acknowledging the enormity of the bacteria problem within the state, in September 2006, TCEQ and the Texas State Soil and Water Conservation Board (TSSWCB...) established a joint Task Force on Bacteria Total Maximum Daily Loads (TMDLs) to make recommenda- tions to strengthen the agencies? efforts in cleaning up bacteria- contaminated waters. Dr. Allan Jones, formerly of the Texas Water Resources Institute...

  18. Beating bacteria: Scientists work to understand and track bacteria in water

    E-print Network

    Wythe, Kathy

    2010-01-01

    tx H2O | pg. 11 Story by Kathy Wythe Bacteria Task Force Recommendations Acknowledging the enormity of the bacteria problem within the state, in September 2006, TCEQ and the Texas State Soil and Water Conservation Board (TSSWCB...) established a joint Task Force on Bacteria Total Maximum Daily Loads (TMDLs) to make recommenda- tions to strengthen the agencies? efforts in cleaning up bacteria- contaminated waters. Dr. Allan Jones, formerly of the Texas Water Resources Institute...

  19. GROWTH INHIBITION OF MEDICALLY ANTIBIOTIC RESISTANT BACTERIA BY SPONGE-ASSOCIATED BACTERIA

    Microsoft Academic Search

    Ocky Karna Radjasa

    2008-01-01

    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

  20. The Effect of Phylogenetically Different Bacteria on the Fitness of Pseudomonas fluorescens in Sand Microcosms

    PubMed Central

    Tyc, Olaf; Wolf, Alexandra B.; Garbeva, Paolina

    2015-01-01

    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

  1. An overview of the alpha-, beta- and gamma-carbonic anhydrases from Bacteria: can bacterial carbonic anhydrases shed new light on evolution of bacteria?

    PubMed

    Capasso, Clemente; Supuran, Claudiu T

    2015-04-01

    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 ? HCO3(-)+?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

  2. MICROBIOLOGY: How Bacteria Change Gear

    NSDL National Science Digital Library

    Richard M. Berry (University of Oxford; Department of Physics, Clarendon Lab)

    2008-06-20

    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.

  3. [Carboxylation enzymes of coryneform bacteria].

    PubMed

    Baryshnikova, L M; Loginova, N V

    1979-01-01

    The enzymes of carbon dioxide heterotrophic fixation were studied in six strains of coryneform bacteria belonging to the genera Arthrobacter, Brevibacterium, Corynebacterium and Nocardia. All of the strains were found to contain PEP (phosphoenolpyruvate) carboxylase (EC 4.1.1.31), NADP or NAD dependent malic enzymes (EC 1.1.1.38--40). Pyruvate carboxylase (EC 6.4.1.1) was found only in three strains of coryneforms: Brevibacterium ammoniagenes, Corynebacterium aquaticum and Nocardia erythropolis. PEP carboxykinase (EC 4.1.1.32) was detected in Brevibacterium ammoniagenes and Nocardia erythropolis. PEP carboxytransphosphorylase (EC 4.1.1.38) was found only in Brevibacterium ammoniagenes. These data suggest that carboxylation of C3-acids is one of the essential pathways in some coryneforms supplying the citric acid cycle with the products of glycolysis. The composition and the level of carboxylation enzymes reflect the ecological characteristics of the organisms rather than their taxonomical relations. PMID:119147

  4. Glycerol Monolaurate Inhibits the Effects of Gram Positive Select Agents on Eukaryotic Cells†

    PubMed Central

    Peterson, Marnie L.; Schlievert, Patrick M.

    2008-01-01

    Many exotoxins of gram positive bacteria, such as superantigens (staphylococcal enterotoxins, toxic shock syndrome toxin-1 [TSST-1], and streptococcal pyrogenic exotoxins) and anthrax toxin are bioterrorism agents that cause diseases by immunostimulation or cytotoxicity. Glycerol monolaurate (GML), a fatty acid monoester found naturally in humans, has been reported to prevent synthesis of gram positive bacterial exotoxins. This study explored the ability of GML to inhibit the effects of exotoxins on mammalian cells and prevent rabbit lethality from TSS. GML (?10 ug/ml) inhibited superantigen (5 ug/ml) immunoproliferation, as determined by inhibition of 3H-thymidine incorporation into DNA of human peripheral blood mononuclear cells (1 × 106 cells/ml) as well as phospholipase C?1, suggesting inhibition of signal transduction. The compound (20 ug/ml) prevented superantigen (100 ug/ml) induced cytokine secretion by human vaginal epithelial cells (HVECs) as measured by ELISA. GML (250 ug) inhibited rabbit lethality due to TSST-1 administered vaginally. GML (10 ug/ml) inhibited HVEC and macrophage cytotoxicity by anthrax toxin, prevented erythrocyte lysis by purified hemolysins (staphylococcal ? and ?) and culture fluids containing streptococcal and Bacillus anthracis hemolysins, and was non-toxic to mammalian cells (up to 100 ug/ml) and rabbits (250 ug). GML stabilized mammalian cell membranes, as erythrocyte lysis was reduced in the presence of hypotonic aqueous solutions (0 to 0.05 M saline) or staphylococcal ? and ?-hemolysins when erythrocytes were pretreated with GML. GML may be useful in management of gram positive exotoxin illnesses; its action appears to be membrane stabilization with inhibition of signal transduction. PMID:16475828

  5. Immunology Taught by Bacteria Russell E. Vance

    E-print Network

    Vance,. Russell

    Immunology Taught by Bacteria Russell E. Vance Received: 11 March 2010 /Accepted: 12 March 2010 multiple pathogenic bacteria. Conclusion Thus, immunology taught by L. pneumophila may lead to a more "Immunology Taught by Viruses" [1]. Zinkerna- gel's message was targeted to a generation of immunolo- gists

  6. Bacteria are like Popeye the sailor man

    NSDL National Science Digital Library

    American Association for the Advancement of Science (AAAS; )

    2004-09-10

    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.

  7. Systemic resistance induced by rhizosphere bacteria

    Microsoft Academic Search

    L. C. van Loon; P. A. H. M. Bakker; C. M. J. Pieterse

    1998-01-01

    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

  8. Mechanisms of Sodium Transport in Bacteria

    Microsoft Academic Search

    P. Dimroth

    1990-01-01

    In some bacteria, an Na^+ circuit is an important link between exergonic and endergonic membrane reactions. The physiological importance of Na^+ ion cycling is described in detail for three different bacteria. Klebsiella pneumoniae fermenting citrate pumps Na^+ outwards by oxaloacetate decarboxylase and uses the Na^+ ion gradient thus established for citrate uptake. Another possible function of the Na^+ gradient may

  9. Pathogenic bacteria and timing of laying

    PubMed Central

    Møller, Anders Pape; Soler, Juan J; Nielsen, Jan Tøttrup; Galván, Ismael

    2015-01-01

    Pathogenic bacteria constitute a serious threat to viability of many organisms. Because growth of most bacteria is favored by humid and warm environmental conditions, earlier reproducers in seasonal environments should suffer less from the negative consequences of pathogenic bacteria. These relationships, and the effects on reproductive success, should be particularly prominent in predators because they are frequently exposed to pathogenic microorganisms from sick prey. Here, we presented and tested this hypothesis by sampling bacteria on adult and nestling goshawks Accipiter gentilis. We predicted that early breeders and their offspring should have fewer bacteria than those reproducing later during the breeding season. Adult goshawks with a high abundance of Staphylococcus on their beak and claws were easier to capture and their laying date was delayed. Moreover, goshawks that laid their eggs later had offspring with more Staphylococcus on their beaks and claws. The strength of the association between laying date and bacterial density of nestlings was stronger during the warm spring of 2013, when nestlings suffered from a higher abundance of pathogenic bacteria. Hatching failure and fledging failure were more common in nests with a higher abundance of Staphylococcus independently of the number of years occupied, laying date, and age of the female nest owner. These findings imply that timing of reproduction may be under the influence of pathogenic bacteria. Because early breeding goshawks produce more recruits than later breeders, our results suggest a role for pathogenic bacteria in the optimal timing of reproduction. PMID:25937910

  10. Pathogenic bacteria and timing of laying.

    PubMed

    Møller, Anders Pape; Soler, Juan J; Nielsen, Jan Tøttrup; Galván, Ismael

    2015-04-01

    Pathogenic bacteria constitute a serious threat to viability of many organisms. Because growth of most bacteria is favored by humid and warm environmental conditions, earlier reproducers in seasonal environments should suffer less from the negative consequences of pathogenic bacteria. These relationships, and the effects on reproductive success, should be particularly prominent in predators because they are frequently exposed to pathogenic microorganisms from sick prey. Here, we presented and tested this hypothesis by sampling bacteria on adult and nestling goshawks Accipiter gentilis. We predicted that early breeders and their offspring should have fewer bacteria than those reproducing later during the breeding season. Adult goshawks with a high abundance of Staphylococcus on their beak and claws were easier to capture and their laying date was delayed. Moreover, goshawks that laid their eggs later had offspring with more Staphylococcus on their beaks and claws. The strength of the association between laying date and bacterial density of nestlings was stronger during the warm spring of 2013, when nestlings suffered from a higher abundance of pathogenic bacteria. Hatching failure and fledging failure were more common in nests with a higher abundance of Staphylococcus independently of the number of years occupied, laying date, and age of the female nest owner. These findings imply that timing of reproduction may be under the influence of pathogenic bacteria. Because early breeding goshawks produce more recruits than later breeders, our results suggest a role for pathogenic bacteria in the optimal timing of reproduction. PMID:25937910

  11. Why and How Bacteria Localize Proteins

    NSDL National Science Digital Library

    L. Shapiro (Stanford University; Department of Developmental Biology)

    2009-11-27

    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.

  12. Method of dispersing a hydrocarbon using bacteria

    DOEpatents

    Tyndall, R.L.

    1996-09-24

    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.

  13. Method of dispersing a hydrocarbon using bacteria

    DOEpatents

    Tyndall, Richard L. (Clinton, TN)

    1996-01-01

    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.

  14. Intracellular bacteria find the right motion.

    PubMed

    Gouin, Edith; Torres, Juan-Jose Quereda; Cossart, Pascale

    2015-04-01

    Benanti et al. report that Burkholderia pseudomallei and Burkholderia mallei bacteria express proteins that mimic Ena/Vasp family proteins to polymerize actin, thereby inducing actin-based motility. Thus, bacteria can use the various cellular actin polymerization mechanisms for intra- and inter-cellular dissemination. PMID:25860603

  15. Evolutionary Genomics of Lactic Acid Bacteria

    Microsoft Academic Search

    Kira S. Makarova; Eugene V. Koonin

    2007-01-01

    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,

  16. Modulating immune responses with probiotic bacteria

    Microsoft Academic Search

    Takeshi Matsuzaki; James Chin

    2000-01-01

    For many years, probiotic bacteria have been known to confer health benefits to the consumer. One possible mechanism for this may be the ability of probiotic bacteria to modulate immune responses. Oral administration of Lactobacillus casei strain Shirota (LcS) has been found to enhance innate immunity by stimulating the activity of splenic NK cells. Oral feeding with killed LcS was

  17. Symbiosis of methanogenic bacteria and sapropelic protozoa

    Microsoft Academic Search

    Johan J. A. van Bruggen; Claudius K. Stumm; Godfried D. Vogels

    1983-01-01

    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.

  18. Predator vs aliens: bacteria interactions with Acanthamoeba.

    PubMed

    Khan, Naveed Ahmed; Siddiqui, Ruqaiyyah

    2014-06-01

    By interactions with other microbes, free-living amoebae play a significant role in microbiology, environmental biology, physiology, cellular interactions, ecology and evolution. Here, we discuss astonishing interactions of bacteria and amoebae, in the light of evolution and functional aspects impacting human health. In favourable environmental conditions, the interaction of Acanthamoeba with non-virulent bacteria results in lysis of the bacteria. However, the interaction with weak-virulent bacteria results in a symbiotic relationship or amoebal lysis may occur. The microbial survival of amoebae in harsh environments, ability to interact with bacteria, and their ability to aid transmission to susceptible hosts is of great concern to human, animal and ecosystem health. PMID:24512693

  19. Chemotactic selection of pollutant degrading soil bacteria

    DOEpatents

    Hazen, T.C.

    1991-03-04

    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.

  20. HYDROCARBON-DEGRADING BACTERIA AND SURFACTANT ACTIVITY

    SciTech Connect

    Brigmon, R; Topher Berry, T; Grazyna A. Plaza, G; jacek Wypych, j

    2006-08-15

    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.

  1. Rice seeds as sources of endophytic bacteria.

    PubMed

    Kaga, Hiroko; Mano, Hironobu; Tanaka, Fumiko; Watanabe, Asuka; Kaneko, Satoshi; Morisaki, Hisao

    2009-01-01

    Endophytic bacteria are considered to originate from the external environment. To examine the hypothesis that rice (Oryza sativa, cultivar Kinuhikari) seeds are a source of endophytic bacteria, we isolated endophytic bacteria from the shoots, remains of the seeds, and roots of rice seedlings that were aseptically cultivated in vitro from surface-disinfected seeds. Of the various bacterial strains isolated, the closest relatives, identified by 16S rRNA gene sequencing, were: Bacillus firmus, B. fusiformis, B. pumilus, Caulobacter crescentus, Kocuria palustris, Micrococcus luteus, Methylobacterium fujisawaense, Me. radiotolerans, and Pantoea ananatis. The latter three species have been detected frequently inside both rice seedlings and mature rice plants. These results indicate that rice seeds are an important source of endophytic bacteria. The bacteria that colonize the seed interior appear to infect the subsequent generation via rice seeds and become the dominant endophytic species in the mature plant. PMID:21566368

  2. MRSA, Clostridium difficile and Other Drug Resistant Bacteria Information for Patients and Families What is Drug Resistant Bacteria?

    E-print Network

    Oliver, Douglas L.

    MRSA, Clostridium difficile and Other Drug Resistant Bacteria Information for Patients and Families What is Drug Resistant Bacteria? Drug Resistant Bacteria also referred to as Multi Drug Resistant Bacteria? Drug Resistant Bacteria are germs that can not be treated by some antibiotics often used to treat

  3. Stop the Spread of Superbugs: Help Fight Drug Resistant Bacteria

    MedlinePLUS

    ... the Spread of Superbugs Help Fight Drug-Resistant Bacteria For nearly a century, bacteria-fighting drugs known as antibiotics have helped to control and destroy many of the harmful bacteria that can make us sick. But in recent ...

  4. Seeing green bacteria in a new light: genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria

    Microsoft Academic Search

    Niels-Ulrik Frigaard; Donald A. Bryant

    2004-01-01

    Based upon their photosynthetic nature and the presence of a unique light-harvesting antenna structure, the chlorosome, the photosynthetic green bacteria are defined as a distinctive group in the Bacteria. However, members of the two taxa that comprise this group, the green sulfur bacteria (Chlorobi) and the filamentous anoxygenic phototrophic bacteria (“Chloroflexales”), are otherwise quite different, both physiologically and phylogenetically. This

  5. Evidence for Direct Electron Transfer by a Gram-Positive Bacterium Isolated from a Microbial Fuel Cell?†

    PubMed Central

    Wrighton, K. C.; Thrash, J. C.; Melnyk, R. A.; Bigi, J. P.; Byrne-Bailey, K. G.; Remis, J. P.; Schichnes, D.; Auer, M.; Chang, C. J.; Coates, J. D.

    2011-01-01

    Despite their importance in iron redox cycles and bioenergy production, the underlying physiological, genetic, and biochemical mechanisms of extracellular electron transfer by Gram-positive bacteria remain insufficiently understood. In this work, we investigated respiration by Thermincola potens strain JR, a Gram-positive isolate obtained from the anode surface of a microbial fuel cell, using insoluble electron acceptors. We found no evidence that soluble redox-active components were secreted into the surrounding medium on the basis of physiological experiments and cyclic voltammetry measurements. Confocal microscopy revealed highly stratified biofilms in which cells contacting the electrode surface were disproportionately viable relative to the rest of the biofilm. Furthermore, there was no correlation between biofilm thickness and power production, suggesting that cells in contact with the electrode were primarily responsible for current generation. These data, along with cryo-electron microscopy experiments, support contact-dependent electron transfer by T. potens strain JR from the cell membrane across the 37-nm cell envelope to the cell surface. Furthermore, we present physiological and genomic evidence that c-type cytochromes play a role in charge transfer across the Gram-positive bacterial cell envelope during metal reduction. PMID:21908627

  6. The unique regulation of iron-sulfur cluster biogenesis in a Gram-positive bacterium

    PubMed Central

    Santos, Joana A.; Alonso-García, Noelia; Macedo-Ribeiro, Sandra; Pereira, Pedro José Barbosa

    2014-01-01

    Iron-sulfur clusters function as cofactors of a wide range of proteins, with diverse molecular roles in both prokaryotic and eukaryotic cells. Dedicated machineries assemble the clusters and deliver them to the final acceptor molecules in a tightly regulated process. In the prototypical Gram-negative bacterium Escherichia coli, the two existing iron-sulfur cluster assembly systems, iron-sulfur cluster (ISC) and sulfur assimilation (SUF) pathways, are closely interconnected. The ISC pathway regulator, IscR, is a transcription factor of the helix-turn-helix type that can coordinate a [2Fe-2S] cluster. Redox conditions and iron or sulfur availability modulate the ligation status of the labile IscR cluster, which in turn determines a switch in DNA sequence specificity of the regulator: cluster-containing IscR can bind to a family of gene promoters (type-1) whereas the clusterless form recognizes only a second group of sequences (type-2). However, iron-sulfur cluster biogenesis in Gram-positive bacteria is not so well characterized, and most organisms of this group display only one of the iron-sulfur cluster assembly systems. A notable exception is the unique Gram-positive dissimilatory metal reducing bacterium Thermincola potens, where genes from both systems could be identified, albeit with a diverging organization from that of Gram-negative bacteria. We demonstrated that one of these genes encodes a functional IscR homolog and is likely involved in the regulation of iron-sulfur cluster biogenesis in T. potens. Structural and biochemical characterization of T. potens and E. coli IscR revealed a strikingly similar architecture and unveiled an unforeseen conservation of the unique mechanism of sequence discrimination characteristic of this distinctive group of transcription regulators. PMID:24847070

  7. Porphyrin Metabolisms in Human Skin Commensal Propionibacterium acnes Bacteria: Potential Application to Monitor Human Radiation Risk

    PubMed Central

    Shu, M.; Kuo, S.; Wang, Y.; Jiang, Y.; Liu, Y.-T.; Gallo, R.L.; Huang, C.-M.

    2013-01-01

    Propionibacterium acnes (P. acnes), a Gram-positive anaerobic bacterium, is a commensal organism in human skin. Like human cells, the bacteria produce porphyrins, which exhibit fluorescence properties and make bacteria visible with a Wood’s lamp. In this review, we compare the porphyrin biosynthesis in humans and P. acnes. Also, since P. acnes living on the surface of skin receive the same radiation exposure as humans, we envision that the changes in porphyrin profiles (the absorption spectra and/or metabolism) of P. acnes by radiation may mirror the response of human cells to radiation. The porphyrin profiles of P. acnes may be a more accurate reflection of radiation risk to the patient than other biodosimeters/biomarkers such as gene up-/down-regulation, which may be non-specific due to patient related factors such as autoimmune diseases. Lastly, we discuss the challenges and possible solutions for using the P. acnes response to predict the radiation risk. PMID:23231351

  8. Novel mineral-oxidizing bacteria from Montserrat (W.I.): physiological and phylogenetic characteristics

    SciTech Connect

    A. Yahya; F. F. Roberto; D. B. Johnson

    1999-06-01

    Four mesophilic acidophilic bacteria isolated from the Caribbean island of Montserrat have been studied to establish their taxonomic relationship to other metal-metabolizing bacteria and to analyze their potential role in mineral processing. Two of the isolates have some physiological and morphological traits in common with Thiobacillus ferrooxidans (Gram negative, iron-oxidizing mesophilic rods) but differed from T. ferrooxidans in displaying chemolitho-heterotrophic growth in ferrous iron/yeast extract medium and greater sensitivity to some metals. Isolates RIV-14 and L-15 were, in contrast, Gram positive, spore-forming rods that displayed considerable metabolic flexibility, and resembled moderately thermophilic Sulfobacillus spp. All the Montserrat isolates were able to oxidize pyrite in pure culture.

  9. Electromechanical and elastic probing of bacteria in a cell culture medium.

    PubMed

    Thompson, G L; Reukov, V V; Nikiforov, M P; Jesse, S; Kalinin, S V; Vertegel, A A

    2012-06-22

    Rapid phenotype characterization and identification of cultured cells, which is needed for progress in tissue engineering and drug testing, requires an experimental technique that measures physical properties of cells with sub-micron resolution. Recently, band excitation piezoresponse force microscopy (BEPFM) has been proven useful for recognition and imaging of bacteria of different types in pure water. Here, the BEPFM method is performed for the first time on physiologically relevant electrolyte media, such as Dulbecco's phosphate-buffered saline (DPBS) and Dulbecco's modified Eagle's medium (DMEM). Distinct electromechanical responses for Micrococcus lysodeikticus (Gram-positive) and Pseudomonas fluorescens (Gram-negative) bacteria in DPBS are demonstrated. The results suggest that mechanical properties of the outer surface coating each bacterium, as well as the electrical double layer around them, are responsible for the BEPFM image formation mechanism in electrolyte media. PMID:22641388

  10. Electromechanical and elastic probing of bacteria in a cell culture medium

    NASA Astrophysics Data System (ADS)

    Thompson, G. L.; Reukov, V. V.; Nikiforov, M. P.; Jesse, S.; Kalinin, S. V.; Vertegel, A. A.

    2012-06-01

    Rapid phenotype characterization and identification of cultured cells, which is needed for progress in tissue engineering and drug testing, requires an experimental technique that measures physical properties of cells with sub-micron resolution. Recently, band excitation piezoresponse force microscopy (BEPFM) has been proven useful for recognition and imaging of bacteria of different types in pure water. Here, the BEPFM method is performed for the first time on physiologically relevant electrolyte media, such as Dulbecco’s phosphate-buffered saline (DPBS) and Dulbecco’s modified Eagle’s medium (DMEM). Distinct electromechanical responses for Micrococcus lysodeikticus (Gram-positive) and Pseudomonas fluorescens (Gram-negative) bacteria in DPBS are demonstrated. The results suggest that mechanical properties of the outer surface coating each bacterium, as well as the electrical double layer around them, are responsible for the BEPFM image formation mechanism in electrolyte media.

  11. Genomewide expression analysis in amino acid-producing bacteria using DNA microarrays.

    PubMed

    Polen, Tino; Wendisch, Volker F

    2004-01-01

    DNA microarray technology has become an important research tool for biotechnology and microbiology. It is now possible to characterize genetic diversity and gene expression in a genomewide manner. DNA microarrays have been applied extensively to study the biology of many bacteria including Escherichia coli, but only recently have they been developed for the Gram-positive Corynebacterium glutamicum. Both bacteria are widely used for biotechnological amino acid production. In this article, in addition to the design and generation of microarrays as well as their use in hybridization experiments and subsequent data analysis, we describe recent applications of DNA microarray technology regarding amino acid production in C. glutamicum and E. coli. We also discuss the impact of functional genomics studies on fundamental as well as applied aspects of amino acid production with C. glutamicum and E. coli. PMID:15304751

  12. Multi-wavelength resonance Raman spectroscopy of bacteria to study the effects of growth condition

    NASA Astrophysics Data System (ADS)

    Kunapareddy, Nagapratima; Grun, Jacob; Lunsford, Robert; Gillis, David; Nikitin, Sergei; Wang, Zheng

    2012-06-01

    We will examine the use of multi-wavelength UV resonance-Raman signatures to identify the effects of growth phase on different types of bacteria. Gram positive and gram-negative species, Escherichia coli, Bacillus cereus, Citrobacter koseri and Citrobacter braakii were grown to logarithmic and stationary phases in different culture media. Raman spectra of bacteria were obtained by sequential illumination of samples between 220 and 260 nm; a range which encompasses the resonance frequencies of cellular components. In addition to the information contained in the single spectrum, this two-dimensional signature contains information reflecting variations in resonance cross sections with illumination wavelength. Results of our algorithms in identifying the differences between these germs are discussed. Preliminary results indicate that growth affects the Raman signature, but not to an extent that would negate identification of the species.

  13. Nitrifying Bacteria in Wastewater Reservoirs

    PubMed Central

    Abeliovich, Aharon

    1987-01-01

    Deep wastewater reservoirs are used throughout Israel to store domestic wastewater effluents for summer irrigation. These effluents contain high concentrations of ammonia (?5 mM) that are frequently toxic to photosynthetic microorganisms and that lead to development of anoxic conditions. Population dynamics of nitrifying bacteria and rates of nitrification were studied in two wastewater reservoirs that differed in organic load and degree of oxygenation and in the laboratory under controlled conditions, both by serial dilutions in mineral medium and microscopically with fluorescein isothiocyanate-conjugated antibodies prepared against local isolates. The difference in counts by the two methods was within 1 order of magnitude. In the laboratory, an O2 concentration of 0.2 mg liter?1 was close to optimal with respect to growth of NH3 oxidizers on domestic wastewater, while O2 concentrations of 0.05 mg liter?1 supported significant rates of nitrification. It was found that even hypertrophic anaerobic environments such as the anaerobic hypolimnion of the wastewater reservoir or the anaerobic settling ponds are capable of sustaining a viable, although not actively nitrifying, population of Nitrosomonas spp. and Nitrobacter spp., in contrast to their rapid decline when maintained anaerobically in mineral medium in the laboratory. Nitrification rates of NH3 in effluents during storage in the reservoirs were slower by 1 to 2 orders of magnitude compared with corresponding rates in water samples brought to the laboratory. The factors causing this inhibition were not identified. PMID:16347319

  14. Comparative cytotoxicity of periodontal bacteria

    SciTech Connect

    Stevens, R.H.; Hammond, B.F.

    1988-11-01

    The direct cytotoxicity of sonic extracts (SE) from nine periodontal bacteria for human gingival fibroblasts (HGF) was compared. Equivalent dosages (in terms of protein concentration) of SE were used to challenge HGF cultures. The cytotoxic potential of each SE was assessed by its ability to (1) inhibit HGF proliferation, as measured by direct cell counts; (2) inhibit 3H-thymidine incorporation in HGF cultures; or (3) cause morphological alterations of the cells in challenged cultures. The highest concentration (500 micrograms SE protein/ml) of any of the SEs used to challenge the cells was found to be markedly inhibitory to the HGFs by all three of the criteria of cytotoxicity. At the lowest dosage tested (50 micrograms SE protein/ml); only SE from Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Fusobacterium nucleatum caused a significant effect (greater than 90% inhibition or overt morphological abnormalities) in the HGFs as determined by any of the criteria employed. SE from Capnocytophaga sputigena, Eikenella corrodens, or Wolinella recta also inhibited cell proliferation and thymidine incorporation at this dosage; however, the degree of inhibition (5-50%) was consistently, clearly less than that of the first group of three organisms named above. The SE of the three other organisms tested (Actinomyces odontolyticus, Bacteroides intermedius, and Streptococcus sanguis) had little or no effect (0-10% inhibition) at this concentration. The data suggest that the outcome of the interaction between bacterial components and normal resident cells of the periodontium is, at least in part, a function of the bacterial species.

  15. Aromatic aminotransferases in coryneform bacteria.

    PubMed

    Fazel, A M; Jensen, R A

    1979-11-01

    Species of coryneform bacteria (Corynebacterium glutamicum, Brevibacterium flavum, and B. ammoniagenes) are capable of transaminating all three of the aromatic pathway intermediates; prephenate, phenylpyruvate, and 4-hydroxy-phenylpyruvate. Two molecular species of aromatic aminotransferase (denoted aminotransferase I and aminotransferase II) were partially purified from C. glutamicum and B. flavum, whereas a single aromatic aminotransferase was isolated from B. ammoniagenes. In both C. glutamicum and B. flavum, aromatic aminotransferase I and aromatic aminotransferase II have molecular weights of about 155,000 and 260,000 respectively. The two aromatic aminotransferases from C. glutamicum and B. flavum, although exhibiting a similar spectrum of overlapping specificities, differ substantially in substrate preference. Pyridoxal-5'-phosphate is tightly associated with these aminotransferases, since little loss of activity was detected when partially purified enzyme preparations were assayed in the absence of exogenous pyridoxal-5'-phosphate. The aminotransferases are quite sensitive to inhibition by phenylhydrazine. This has practical application when assay of prephenate dehydratase is desired in the presence of aromatic aminotransferase activity since potentially trivial interference can be negated by selective phenylhydrazine inhibition of aromatic aminotransferase activity. At 0.1 mM concentrations of phenylhydrazine, 90% inhibitions of aminotransferase activities were achieved in partially purified preparations of B. flavum and C. glutamicum. PMID:500563

  16. Tape Cassette Bacteria Detection System

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The design, fabrication, and testing of an automatic bacteria detection system with a zero-g capability and based on the filter-capsule approach is described. This system is intended for monitoring the sterility of regenerated water in a spacecraft. The principle of detection is based on measuring the increase in chemiluminescence produced by the action of bacterial porphyrins (i.e., catalase, cytochromes, etc.) on a luminol-hydrogen peroxide mixture. Since viable as well as nonviable organisms initiate this luminescence, viable organisms are detected by comparing the signal of an incubated water sample with an unincubated control. Higher signals for the former indicate the presence of viable organisms. System features include disposable sealed sterile capsules, each containing a filter membrane, for processing discrete water samples and a tape transport for moving these capsules through a processing sequence which involves sample concentration, nutrient addition, incubation, a 4 Molar Urea wash and reaction with luminol-hydrogen peroxide in front of a photomultiplier tube. Liquids are introduced by means of a syringe needle which pierces a rubber septum contained in the wall of the capsule. Detection thresholds obtained with this unit towards E. coli and S. marcescens assuming a 400 ml water sample are indicated.

  17. Effects of Methanol Extract of Wedelia chinensis Osbeck (Asteraceae) Leaves against Pathogenic Bacteria with Emphasise on Bacillus cereus

    PubMed Central

    Darah, I.; Lim, S. H.; Nithianantham, K.

    2013-01-01

    The antibacterial activity of the methanol extract of Wedelia chinensis leave was studied and tested against three pathogenic Gram positive bacteria (Bacillus cereus, B. subtilis and Stapylococcus aureus) and three pathogenic Gram negative bacteria (Escherichia coli, Proteus rettgeri and Pseudomonas aeruginosa) by the disk diffusion assay and broth dilution methods. The extract exhibited favourable antibacterial activity against the bacterial cells but was more potent against Gram positive bacteria with the minimum inhibition concentration of 3.12 to 6.25 mg/ml compared to the Gram negative bacteria which had minimum inhibition concentration values of 25 mg/ml. The time-kill study suggested that the extract possessed bactericidal properties at higher concentrations and eradicated the growth of bacterial cells. The major abnormalities occurred to the bacterial cells after exposed to the extract were complete alterations in their morphology and collapsed of the cells beyond repair. The methanol extract of W. chinensis may be an effective antibacterial agent to treat bacterial infections. PMID:24403653

  18. Effects of Methanol Extract of Wedelia chinensis Osbeck (Asteraceae) Leaves against Pathogenic Bacteria with Emphasise on Bacillus cereus.

    PubMed

    Darah, I; Lim, S H; Nithianantham, K

    2013-09-01

    The antibacterial activity of the methanol extract of Wedelia chinensis leave was studied and tested against three pathogenic Gram positive bacteria (Bacillus cereus, B. subtilis and Stapylococcus aureus) and three pathogenic Gram negative bacteria (Escherichia coli, Proteus rettgeri and Pseudomonas aeruginosa) by the disk diffusion assay and broth dilution methods. The extract exhibited favourable antibacterial activity against the bacterial cells but was more potent against Gram positive bacteria with the minimum inhibition concentration of 3.12 to 6.25 mg/ml compared to the Gram negative bacteria which had minimum inhibition concentration values of 25 mg/ml. The time-kill study suggested that the extract possessed bactericidal properties at higher concentrations and eradicated the growth of bacterial cells. The major abnormalities occurred to the bacterial cells after exposed to the extract were complete alterations in their morphology and collapsed of the cells beyond repair. The methanol extract of W. chinensis may be an effective antibacterial agent to treat bacterial infections. PMID:24403653

  19. Light scattering by marine heterotrophic bacteria

    NASA Technical Reports Server (NTRS)

    Ulloa, Osvaldo; Sathyendranath, Shubha; Platt, Trevor; Quinones, Renato A.

    1992-01-01

    Mie theory is applied to estimate scattering by polydispersions of marine heterotrophic bacteria, and a simple expression is derived for the bacterial scattering coefficient. The error incurred in deriving bacterial optical properties by use of the van de Hulst approximations is computed. The scattering properties of natural bacterial assemblages in three marine environments, Georges Bank, Northeast Channel, and Sargasso Sea, are assessed by applying Mie theory to field data on bacterial size and abundance. Results are used to examine the potential contribution of bacteria to the scattering properties of seawater. The utility of using pigment data to predict the magnitude of scattering by bacteria is discussed.

  20. ADAPTATIONS OF INDIGENOUS BACTERIA TO FUEL CONTAMINATION IN KARST AQUIFERS IN SOUTH-CENTRAL KENTUCKY

    USGS Publications Warehouse

    Byl, Thomas D.; Metge, David W.; Daniel T. Agymang; Bradley, Michael W.; Hileman, Gregg; Harvey, Ronald W.

    2014-01-01

    The karst aquifer systems in southern Kentucky can be dynamic and quick to change. Microorganisms that live in these unpredictable aquifers are constantly faced with environmental changes. Their survival depends upon adaptations to changes in water chemistry, taking advantage of positive stimuli and avoiding negative environmental conditions. The U.S. Geological Survey conducted a study in 2001 to determine the capability of bacteria to adapt in two distinct regions of water quality in a karst aquifer, an area of clean, oxygenated groundwater and an area where the groundwater was oxygen depleted and contaminated by jet fuel. Water samples containing bacteria were collected from one clean well and two jet fuel contaminated wells in a conduit-dominated karst aquifer. Bacterial concentrations, enumerated through direct count, ranged from 500,000 to 2.7 million bacteria per mL in the clean portion of the aquifer, and 200,000 to 3.2 million bacteria per mL in the contaminated portion of the aquifer over a twelve month period. Bacteria from the clean well ranged in size from 0.2 to 2.5 mm, whereas bacteria from one fuel-contaminated well were generally larger, ranging in size from 0.2 to 3.9 mm. Also, bacteria collected from the clean well had a higher density and, consequently, were more inclined to sink than bacteria collected from contaminated wells. Bacteria collected from the clean portion of the karst aquifer were predominantly (,95%) Gram-negative and more likely to have flagella present than bacteria collected from the contaminated wells, which included a substantial fraction (,30%) of Gram-positive varieties. The ability of the bacteria from the clean portion of the karst aquifer to biodegrade benzene and toluene was studied under aerobic and anaerobic conditions in laboratory microcosms. The rate of fuel biodegradation in laboratory studies was approximately 50 times faster under aerobic conditions as compared to anaerobic, sulfur-reducing conditions. The optimum pH for fuel biodegradation ranged from 6 to 7. These findings suggest that bacteria have adapted to water-saturated karst systems with a variety of active and passive transport mechanisms.

  1. Influence of Sulfate on the Transport of Bacteria in Quartz Sand

    NASA Astrophysics Data System (ADS)

    Shen, Xiufang; Han, Peng; Yang, Haiyan; Kim, Hyunjung; Tong, Meiping

    2013-04-01

    The influence of sulfate on the transport of bacteria in packed quartz sand was examined at a constant 25 mM ionic strength with the sulfate concentration progressively increased from 0 to 20 mM at pH 6.0. Two representative cell types, Escherichia coli BL21 (Gram-negative) and Bacillus subtilis (Gram-positive), were used to determine the effect of sulfate on cell transport behavior. For both examined cell types, the breakthrough plateaus in the presence of sulfate in suspensions were higher and the corresponding retained profiles were lower than those without sulfate ions, indicating that the presence of sulfate in suspensions increased cell transport in packed quartz sand regardless of the examined cell types (Gram-positive or Gram-negative). Moreover, the enhancement of bacteria transport induced by the presence of sulfate was more pronounced with increasing sulfate concentration from 5 to 20 mM. In contrast with the results for EPS-present bacteria, the presence of sulfate in solutions did not change the transport behavior for EPS-removed cells. The zeta potentials of EPS-present cells with sulfate were found to be more negative relative to those without sulfate in suspensions, whereas, the zeta potentials for EPS-removed cells in the presence of sulfate were similar as those without sulfate. We proposed that sulfate could interact with EPS on cell surfaces and thus negatively increased the zeta potentials of bacteria, contributing to the increased transport in the presence of sulfate in suspensions.

  2. Protein(s) from the Gram-Positive Bacterium Clavibacter michiganensis subsp. michiganensis Induces a Hypersensitive Response in Plants.

    PubMed

    Alarcón, C; Castro, J; Muñoz, F; Arce-Johnson, P; Delgado, J

    1998-04-01

    ABSTRACT The gram-positive tomato pathogen Clavibacter michiganensis subsp. michiganensis induced a local necrotic response on four-o'clock (Mirabilis jalapa) and tobacco (Nicotiana tabacum) plants. This necrosis response was characteristic of the hypersensitive response (HR). The cell-free culture supernatant from strain CMM623 also induced a necrosis that was phenotypically similar to that induced by the bacteria. Inhibitors of plant metabolism suppressed the necrotic reaction of both M. jalapa and tobacco. The HR-inducing activity present in the supernatant was heat stable, sensitive to proteases, and had an apparent molecular mass in the range of 35 to 50 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The properties observed for the necrosis-inducing activity resembled harpin and PopA described from gram-negative phytopathogenic bacteria. PMID:18944953

  3. Autocatalytic Intramolecular Isopeptide Bond Formation in Gram-Positive Bacterial Pili: A QM/MM Simulation

    PubMed Central

    Hu, Xiangqian; Hu, Hao; Melvin, Jeffrey A.; Clancy, Kathleen W.; McCafferty, Dewey G.; Yang, Weitao

    2010-01-01

    Gram-positive pathogens possess external pili or fimbrae with which they adhere to host cells during the infection process. Unusual dual intramolecular isopeptide bonds between Asn and Lys side chains within the N-terminal and C-terminal domains of the pilus subunits have been observed initially in the Streptococcus pyogenes pilin subunit Spy0128 and subsequently in GBS52 from Streptococcus agalactiae, in the BcpA major pilin of Bacillus cereus and in the RrgB pilin of Streptococcus pneumoniae among others. Within each pilin subunit, intramolecular isopeptide bonds serve to stabilize the protein. These bonds provide a means to withstand large external mechanical forces, as well as possibly assisting in supporting a conformation favored for pilin subunit polymerization via sortase transpeptidases. Genome-wide analyses of pili-containing Gram-positive bacteria are known or suspected to contain isopeptide bonds in pilin subunits. For the autocatalytic formation of isopeptide crosslinks, a conservation of three amino acids including Asn, Lys, and a catalytically important acidic Glu (or Asp) residue are responsible. However, the chemical mechanism of how isopeptide bonds form within pilin remains poorly understood. Although it is possible that several mechanistic paths could lead to isopeptide bond formation in pili, the requirement of a conserved glutamate and highly organized positioning of residues within the hydrophobic environment of the active site were found in numerous pilin crystal structures such as Spy0128 and RrgB. This suggests a mechanism involving direct coupling of lysine side chain amine to the asparagine carboxamide mediated by critical acid/base or hydrogen bonding interactions with the catalytic glutamate residue. From this mechanistic perspective, we used the QM/MM minimum free-energy path method to examine the reaction details of forming the isopeptide bonds with the Spy0128 as a model pilin, specifically focusing on the role of the glutamate in catalysis. It was determined that the reaction mechanism likely consists of two major steps: the nucleophilic attack on C? by nitrogen in the unprotonated Lys ?-amino group and then two concerted proton transfers occur during the formation of the intramolecular isopeptide bond to subsequently release ammonia. More importantly, within the dual active sites of Spy0128, Glu117 and Glu258 residues function as crucial catalysts for each isopeptide bond formation, respectively, by relaying two proton transfers. This study also suggests that domain-domain interactions within Spy0128 may modulate the reactivity of residues within each active site. Our results may hopefully shed light on the molecular mechanisms of pilin biogenesis in Gram-positive bacteria. PMID:21142157

  4. Efficacy of linezolid on gram-positive bacterial infection in elderly patients and the risk factors associated with thrombocytopenia

    PubMed Central

    Bi, Li-qing; Zhou, Jing; Huang, Ming; Zhou, Su-ming

    2013-01-01

    Objective : Linezolid is active against drug-resistant gram-positive bacteria. However, the efficacy and safety of linezolid in the treatment of the elderly have not been well characterized. The purpose of this study was to evaluate the efficacy of linezolid in the treatment of the elderly with gram-positive bacterial infection and to investigate the risk factors associated with the development of thrombocytopenia in these patients. Methodology: This was a retrospective analysis of 50 elderly patients who were treated with intravenous linezolid for gram-positive bacterial infection. Clinical data and bacteriological responses were assessed. Risk factors associated with thrombocytopenia in elderly patients were analyzed. Results: The overall clinical cure rate of linezolid was 74%, and the bacteriological eradication rate was 69%. Thrombocytopenia occurred in 24 patients, and thrombocytopenia was associated with both the duration of treatment (P = 0.005) and the baseline platelet count (P = 0.042). Based on a logistic regression analysis, the baseline platelet count <200×109/L (OR = 0.244; 95% CI = 0.068- 0.874; P = 0.030) was identified as the only significant risk factor for linezolid-associated thrombocytopenia in elderly patients. The mean platelet count decreased significantly from the 7th day of treatment, and decreased to the lowest value 1-2 days after the end of therapy. Conclusions : Linezolid is effective and safe for the elderly with gram-positive bacterial infections. Adverse effects such as thrombocytopenia are of greater concern. Platelet counts should be monitored in patients who are treated with linezolid and that measures should be taken in advance to avoid hemorrhagic tendencies. PMID:24353639

  5. Fuel from Bacteria: Bioconversion of Carbon Dioxide to Biofuels by Facultatively Autotrophic Hydrogen Bacteria

    SciTech Connect

    None

    2010-07-01

    Electrofuels Project: Ohio State is genetically modifying bacteria to efficiently convert carbon dioxide directly into butanol, an alcohol that can be used directly as a fuel blend or converted to a hydrocarbon, which closely resembles a gasoline. Bacteria are typically capable of producing a certain amount of butanol before it becomes too toxic for the bacteria to survive. Ohio State is engineering a new strain of the bacteria that could produce up to 50% more butanol before it becomes too toxic for the bacteria to survive. Finding a way to produce more butanol more efficiently would significantly cut down on biofuel production costs and help make butanol cost competitive with gasoline. Ohio State is also engineering large tanks, or bioreactors, to grow the biofuel-producing bacteria in, and they are developing ways to efficiently recover biofuel from the tanks.

  6. Plants as Sources of Airborne Bacteria, Including Ice Nucleation-Active Bacteria

    PubMed Central

    Lindemann, Julianne; Constantinidou, Helen A.; Barchet, William R.; Upper, Christen D.

    1982-01-01

    Vertical wind shear and concentration gradients of viable, airborne bacteria were used to calculate the upward flux of viable cells above bare soil and canopies of several crops. Concentrations at soil or canopy height varied from 46 colony-forming units per m3 over young corn and wet soil to 663 colony-forming units per m3 over dry soil and 6,500 colony-forming units per m3 over a closed wheat canopy. In simultaneous samples, concentrations of viable bacteria in the air 10 m inside an alfalfa field were fourfold higher than those over a field with dry, bare soil immediately upwind. The upward flux of viable bacteria over alfalfa was three- to fourfold greater than over dry soil. Concentrations of ice nucleation-active bacteria were higher over plants than over soil. Thus, plant canopies may constitute a major source of bacteria, including ice nucleation-active bacteria, in the air. PMID:16346129

  7. Reverse and flick: Hybrid locomotion in bacteria

    E-print Network

    Stocker, Roman

    Many bacteria are motile. They use one or more helical flagella as propellers, rotating them like the corkscrew on a wine bottle opener. Despite the limited morphological repertoire of the propulsive system, radically ...

  8. [Interaction of bacteria with mercuric compounds].

    PubMed

    Ostrovski?, D N; Lysak, E I; Demina, G R; Biniukov, V I

    2000-01-01

    We investigated the interaction of mercuric compounds with the bacteria Corynebacterium ammoniagenes, Micrococcus luteus, and Mycobacterium smegmatus capable of producing hydroxylamines (R-NOH) and 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MECP), which are prone to form free radicals. The interaction of these substances with Hg2+ ions and their dynamics during the mercuric poisoning of bacteria was studied by EPR and NMR. Under stress conditions induced by lowering pH or generation of active oxygen species, the bacteria and, especially, their mutants with enhanced sensitivity to oxidative stress, were found to respond to exposure to 1-3 micrograms/ml HgCl2 and p-chloromercuribenzoate by a several-fold increase in their viability. The data obtained were interpreted in terms of the involvement of the sulfhydryl groups of bacterial surface proteins in this phenomenon. The interaction of bacteria with mercuric compounds may affect the pathogenesis of tuberculosis and other diseases. PMID:11314647

  9. Methods for dispersing hydrocarbons using autoclaved bacteria

    DOEpatents

    Tyndall, Richard L. (Clinton, TN)

    1996-01-01

    A method of dispersing a hydrocarbon includes the steps: providing a bacterium selected from the following group: ATCC 85527, ATCC 75529, and ATCC 55638, a mutant of any one of these bacteria possessing all the identifying characteristics of any one of these bacteria, and mixtures thereof; autoclaving the bacterium to derive a dispersant solution therefrom; and contacting the dispersant solution with a hydrocarbon to disperse the hydrocarbon. Moreover, a method for preparing a dispersant solution includes the following steps: providing a bacterium selected from the following group: ATCC 75527, ATCC 75529, and ATCC 55638, a mutant of any one of these bacteria possessing all the identifying characteristics of any one of these bacteria, and mixtures thereof; and autoclaving the bacterium to derive a dispersant solution therefrom.

  10. Methods for dispersing hydrocarbons using autoclaved bacteria

    DOEpatents

    Tyndall, R.L.

    1996-11-26

    A method of dispersing a hydrocarbon includes the following steps: providing a bacterium selected from the following group: ATCC 85527, ATCC 75529, and ATCC 55638, a mutant of any one of these bacteria possessing all the identifying characteristics of any one of these bacteria, and mixtures; autoclaving the bacterium to derive a dispersant solution; and contacting the dispersant solution with a hydrocarbon to disperse the hydrocarbon. Moreover, a method for preparing a dispersant solution includes the following steps: providing a bacterium selected from the following group: ATCC 75527, ATCC 75529, and ATCC 55638, a mutant of any one of these bacteria possessing all the identifying characteristics of any one of these bacteria, and mixtures; and autoclaving the bacterium to derive a dispersant solution.

  11. Physiological assessment of bacteria using fluorochromes

    NASA Technical Reports Server (NTRS)

    McFeters, G. A.; Yu, F. P.; Pyle, B. H.; Stewart, P. S.

    1995-01-01

    This minireview focuses on the application of fluorogenic compounds in the detection of bacteria with particular emphasis on the assessment of physiological activity using epifluorescence microscopy. Microbiological applications of several related methods will also be reviewed.

  12. Role of bacteria in oral carcinogenesis

    PubMed Central

    Khajuria, Nidhi; Metgud, Rashmi

    2015-01-01

    Oral cancer appears to be increasing in incidence, and mortality has hardly improved over the past 25 years. Better understanding of the etiopathogenesis should lead to more accurate and earlier diagnosis and more effective treatments with fewer adverse effects. Despite increasing interest in the possible relationships between bacteria and the different stages of cancer development, the association of bacteria with cancer of the oral cavity has yet to be adequately examined. Different bacteria have been proposed to induce carcinogenesis, either through induction of chronic inflammation or by interference, either directly or indirectly, with eukaryotic cell cycle and signaling pathways or by metabolism of potentially carcinogenic substances like acetaldehyde, causing mutagenesis. This review presents the possible carcinogenesis pathway involved in bacterial carcinogenesis, commonly implicated bacteria in oral carcinogenesis and their role in cancer therapeutics as well. PMID:25767359

  13. Genetic information transfer promotes cooperation in bacteria

    E-print Network

    Misevic, Dusan

    Genetic information transfer promotes cooperation in bacteria Tatiana Dimitriua , Chantal Lottona cooperation genes. Several mechanisms that bias the partner association in co- operative interactions have receptor binding (8) can generate a positive assortment among individuals carrying cooperative genes, which

  14. Distribution of phytopathogenic bacteria in infested seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Populations of phytopathogenic bacteria representing five host-pathogen combinations were assessed to determine if there was a mathematical relationship common across seedborne bacterial diseases. Bacterial populations were estimated from naturally-infested seeds of cowpea (Vigna unguiculata), peppe...

  15. THE COMPLEX WORLD OF GASTORINTESTINAL BACTERIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteria in the gastrointestinal (GI) tract are confronted with a constantly changing (and often hostile) environment, including fluctuations in both physical and chemical conditions. Neighboring microorganisms not only contend for substrate but even launch complex chemical attacks with the apparen...

  16. Probiotic Bacteria Induce a ‘Glow of Health’

    E-print Network

    Levkovich, Tatiana

    Radiant skin and hair are universally recognized as indications of good health. However, this ‘glow of health’ display remains poorly understood. We found that feeding of probiotic bacteria to aged mice induced integumentary ...

  17. Magnetotactic Bacteria from Extreme Environments

    NASA Astrophysics Data System (ADS)

    Bazylinski, Dennis A.; Lefère, Christopher T.

    2013-03-01

    Magnetotactic bacteria (MTB) represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4) or greigite (Fe3S4) and cause cells to align along the Earth's geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic-anoxic interface (OAI) in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC) bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.

  18. R-body-producing bacteria.

    PubMed Central

    Pond, F R; Gibson, I; Lalucat, J; Quackenbush, R L

    1989-01-01

    Until 10 years ago, R bodies were known only as diagnostic features by which endosymbionts of paramecia were identified as kappa particles. They were thought to be limited to the cytoplasm of two species in the Paramecium aurelia species complex. Now, R bodies have been found in free-living bacteria and other Paramecium species. The organisms now known to form R bodies include the cytoplasmic kappa endosymbionts of P. biaurelia and P. tetraurelia, the macronuclear kappa endosymbionts of P. caudatum, Pseudomonas avenae (a free-living plant pathogen), Pseudomonas taeniospiralis (a hydrogen-oxidizing soil microorganism), Rhodospirillum centenum (a photosynthetic bacterium), and a soil bacterium, EPS-5028, which is probably a pseudomonad. R bodies themselves fall into five distinct groups, distinguished by size, the morphology of the R-body ribbons, and the unrolling behavior of wound R bodies. In recent years, the inherent difficulties in studying the organization and assembly of R bodies by the obligate endosymbiont kappa, have been alleviated by cloning and expressing genetic determinants for these R bodies (type 51) in Escherichia coli. Type 51 R-body synthesis requires three low-molecular-mass polypeptides. One of these is modified posttranslationally, giving rise to 12 polypeptide species, which are the major structural subunits of the R body. R bodies are encoded in kappa species by extrachromosomal elements. Type 51 R bodies, produced in Caedibacter taeniospiralis, are encoded by a plasmid, whereas bacteriophage genomes probably control R-body synthesis in other kappa species. However, there is no evidence that either bacteriophages or plasmids are present in P. avenae or P. taeniospiralis. No sequence homology was detected between type 51 R-body-encoding DNA and DNA from any R-body-producing species, except C. varicaedens 1038. The evolutionary relatedness of different types of R bodies remains unknown. Images PMID:2651865

  19. A metagenomic assessment of the bacteria associated with Lucilia sericata and Lucilia cuprina (Diptera: Calliphoridae).

    PubMed

    Singh, Baneshwar; Crippen, Tawni L; Zheng, Longyu; Fields, Andrew T; Yu, Ziniu; Ma, Qun; Wood, Thomas K; Dowd, Scot E; Flores, Micah; Tomberlin, Jeffery K; Tarone, Aaron M

    2015-01-01

    Lucilia Robineau-Desvoidy (Diptera: Calliphoridae) is a blow fly genus of forensic, medical, veterinary, and agricultural importance. This genus is also famous because of its beneficial uses in maggot debridement therapy (MDT). Although the genus is of considerable economic importance, our knowledge about microbes associated with these flies and how these bacteria are horizontally and trans-generationally transmitted is limited. In this study, we characterized bacteria associated with different life stages of Lucilia sericata (Meigen) and Lucilia cuprina (Wiedemann) and in the salivary gland of L. sericata by using 16S rDNA 454 pyrosequencing. Bacteria associated with the salivary gland of L. sericata were also characterized using light and transmission electron microscopy (TEM). Results from this study suggest that the majority of bacteria associated with these flies belong to phyla Proteobacteria, Firmicutes, and Bacteroidetes, and most bacteria are maintained intragenerationally, with a considerable degree of turnover from generation to generation. In both species, second-generation eggs exhibited the highest bacterial phylum diversity (20 % genetic distance) than other life stages. The Lucilia sister species shared the majority of their classified genera. Of the shared bacterial genera, Providencia, Ignatzschineria, Lactobacillus, Lactococcus, Vagococcus, Morganella, and Myroides were present at relatively high abundances. Lactobacillus, Proteus, Diaphorobacter, and Morganella were the dominant bacterial genera associated with a survey of the salivary gland of L. sericata. TEM analysis showed a sparse distribution of both Gram-positive and Gram-negative bacteria in the salivary gland of L. sericata. There was more evidence for horizontal transmission of bacteria than there was for trans-generational inheritance. Several pathogenic genera were either amplified or reduced by the larval feeding on decomposing liver as a resource. Overall, this study provides information on bacterial communities associated with different life stages of Lucilia and their horizontal and trans-generational transmission, which may help in the development of better vector-borne disease management and MDT methods. PMID:25306907

  20. Rock-degrading endophytic bacteria in cacti

    Microsoft Academic Search

    M. Esther Puente; Ching Y. Li; Yoav Bashan

    2009-01-01

    A plant–bacterium association of the cardon cactus (Pachycereus pringlei) and endophytic bacteria promotes establishment of seedlings and growth on igneous rocks without soil. These bacteria weather several rock types and minerals, unbind significant amounts of useful minerals for plants from the rocks, fix in vitro N2, produce volatile and non-volatile organic acids, and reduce rock particle size to form mineral

  1. Corrosion inhibition of steel by bacteria

    SciTech Connect

    Hernandez, G.; Kucera, V.; Thierry, D.; Pedersen, A. (Swedish Corrosion Inst., Stockholm (Sweden)); Hermansson, M. (Univ. of Gothenburg (Sweden). Dept. of General and Marine Microbiology)

    1994-08-01

    Mild steel was exposed to Pseudomonas sp. S9 or Serratia marcescens in synthetic seawater. An increase in corrosion resistance over that i natural seawater was monitored by electrochemical techniques. Biological analyses were performed to characterize the system. The inhibition effect also was observed when mild steel was coated with bacteria and then immersed in synthetic seawater. When specimens coated with bacteria were transferred to a natural seawater flow system, the inhibition effect disappeared during the first 2 weeks.

  2. Investigating the Uses of Backyard Bacteria

    NSDL National Science Digital Library

    Elisa Brako

    2009-01-01

    The purpose of this lab is to recognize that the answers to some of society's industrial challenges may lie right in our own backyards. Learners discover how to select protein-digesting bacteria from various soil samples. After isolating the colonies, learners are then encouraged to investigate ways to test the effectiveness of their specimens in breaking down protein stains on clothing. This activity demonstrates how bacteria with specific enzymatic capabilities can be isolated with a simple microbiology technique. Adult supervision recommended.

  3. Biotechnology Curriculum Freshman Exploratory: Growing Bacteria

    NSDL National Science Digital Library

    Kurtz, Mary Jane

    Bacteria are everywhere in the environment. To prove this in this activity, students will take samples of different surfaces around the classroom, and nearby places, as well as their own fingers. To detect bacteria, students will need to provide food for them to grow on. Students will be using the nutrient agar plates that have already been prepared. This lesson plan document may be downloaded in Microsoft Word file format.

  4. Heterotrophic bacteria in Long Island Sound

    Microsoft Academic Search

    R. A. Murchelano; C. Brown

    1970-01-01

    Correlated with a study of heterotrophic bacteria from cultures of larval bivalve molluses, bacteria were studied from the water column over an oyster bed in Lont Island Sound, USA. Samples taken biweekly for 1 year showed bacterial densities ranging from 1.2x103\\/ml in summer to 3.8x104\\/ml in winter. Variation in seasonal density mirrored that of phytoplankton. Gram-negativ rods constituted 99% of

  5. Agencies Approve Bacteria TMDL Task Force Recommendations 

    E-print Network

    Wythe, Kathy

    2007-01-01

    tx H2O | pg. 10 In June 2007 the Texas Commission onEnvironmental Quality (TCEQ) and the TexasState Soil and Water Conservation Board (TSSW- CB) approved the recommendations of the Bacteria Total Maximum Daily Load (TMDL) Task Force and asked... their agencies to update their TMDL guidance documents to reflect these recommendations. They also authorized establishing a multi-agency bacteria TMDL work group to examine the research and development needs identified in the task force report. Both TCEQ...

  6. Agencies Approve Bacteria TMDL Task Force Recommendations

    E-print Network

    Wythe, Kathy

    2007-01-01

    tx H2O | pg. 10 In June 2007 the Texas Commission onEnvironmental Quality (TCEQ) and the TexasState Soil and Water Conservation Board (TSSW- CB) approved the recommendations of the Bacteria Total Maximum Daily Load (TMDL) Task Force and asked... their agencies to update their TMDL guidance documents to reflect these recommendations. They also authorized establishing a multi-agency bacteria TMDL work group to examine the research and development needs identified in the task force report. Both TCEQ...

  7. Polymer-Immobilized Photosensitizers for Continuous Eradication of Bacteria

    PubMed Central

    Valkov, Anton; Nakonechny, Faina; Nisnevitch, Marina

    2014-01-01

    The photosensitizers Rose Bengal (RB) and methylene blue (MB), when immobilized in polystyrene, were found to exhibit high antibacterial activity in a continuous regime. The photosensitizers were immobilized by dissolution in chloroform, together with polystyrene, with further evaporation of the solvent, yielding thin polymeric films. Shallow reservoirs, bottom-covered with these films, were used for constructing continuous-flow photoreactors for the eradication of Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli and wastewater bacteria under illumination with visible white light using a luminescent lamp at a 1.8 mW·cm?2 fluence rate. The bacterial concentration decreased by two to five orders of magnitude in separate reactors with either immobilized RB or MB, as well as in three reactors connected in series, which contained one of the photosensitizers. Bacterial eradication reached more than five orders of magnitude in two reactors connected in series, where the first reactor contained immobilized RB and the second contained immobilized MB. PMID:25158236

  8. Comparative Analysis of Myxococcus Predation on Soil Bacteria ? †

    PubMed Central

    Morgan, Andrew D.; MacLean, R. Craig; Hillesland, Kristina L.; Velicer, Gregory J.

    2010-01-01

    Predator-prey relationships among prokaryotes have received little attention but are likely to be important determinants of the composition, structure, and dynamics of microbial communities. Many species of the soil-dwelling myxobacteria are predators of other microbes, but their predation range is poorly characterized. To better understand the predatory capabilities of myxobacteria in nature, we analyzed the predation performance of numerous Myxococcus isolates across 12 diverse species of bacteria. All predator isolates could utilize most potential prey species to effectively fuel colony expansion, although one species hindered predator swarming relative to a control treatment with no growth substrate. Predator strains varied significantly in their relative performance across prey types, but most variation in predatory performance was determined by prey type, with Gram-negative prey species supporting more Myxococcus growth than Gram-positive species. There was evidence for specialized predator performance in some predator-prey combinations. Such specialization may reduce resource competition among sympatric strains in natural habitats. The broad prey range of the Myxococcus genus coupled with its ubiquity in the soil suggests that myxobacteria are likely to have very important ecological and evolutionary effects on many species of soil prokaryotes. PMID:20802074

  9. Biocompatible nanoparticles trigger rapid bacteria clustering.

    PubMed

    Larsen, Mona Utne; Seward, Matthew; Tripathi, Anubhav; Shapley, Nina C

    2009-01-01

    This study reveals an exciting phenomenon of stimulated bacteria clustering. Rapid aggregation and microbial arrest are shown to occur in Escherichia coli solutions of neutral pH when chitosan nanoparticles with positive zeta potential are added. Because chitosan nanoparticles can easily be dispersed in aqueous buffers, the rapid clustering phenomenon requires only minuscule nanoparticle concentrations and will be critical in developing new methods for extricating bacterial pathogens. This work establishes the dominant role of electrostatic attraction in bacteria-nanoparticle interactions by varying the nanoparticle zeta potential from highly positive to strongly negative values, and by exploring concentration effects. For strongly negative nanoparticles, no clusters form, while aggregates are small and loose at intermediate conditions. In addition, optical density measurements indicate that over 90% of the suspended bacteria flocculate within seconds of being mixed with chitosan nanoparticles of a highly positive surface charge. Finally, the nanoparticles are significantly more efficient as a clustering agent compared to an equal mass of molecular chitosan in solution, as the bacteria-nanoparticle clusters formed are substantially larger. The bacteria-nanoparticle aggregation effect demonstrated here promises a rapid separation method for aiding pathogen detection and for flocculation of bacteria in fermentation processes. PMID:19565661

  10. [Immobilization of introduced bacteria and degradation of pyrene and benzo(alpha) pyrene in soil by immobilized bacteria].

    PubMed

    Wang, Xin; Li, Peijun; Song, Shouzhi; Zhong, Yong; Zhang, Hui; Verkhozina, E V

    2006-11-01

    In this study, introduced bacteria were applied in the bioremediation of pyrene and benzo (alpha) pyrene in organic pollutants-contaminated soils, aimed to test whether it was feasible to introduce bacteria to environmental engineering. Three introduced bacteria were immobilized separately or together to degrade the pyrene and benzo (alpha) pyrene in soil, taking dissociated bacteria as the control, and comparing with three indigenous bacteria. The results showed that immobilized introduced bacteria, either single or mixed, had higher degradation efficiency than dissociated bacteria. Compared with indigenous bacteria, some introduced bacteria had predominance to some degree. The introduced bacteria-mixture had better degradation efficiency after being immobilized. The degradation rate of pyrene and benzo(alpha) pyrene after treated with immobilized bacteria-( B61-B67)-mixture for 96 hours was 43.49% and 38.55%, respectively. PMID:17269358

  11. MIGHTY BACTERIA IN A CIVILISED WORLD Prepared by Amy Wooding

    E-print Network

    MIGHTY BACTERIA IN A CIVILISED WORLD Prepared by Amy Wooding The 2013 FABI/ CTHB UPwith of antibacterial products being advertised. The aim was to explore the idea created by these products that bacteria this by testing whether all bacteria can survive in every environment; will bacteria isolated from the UP

  12. Microbial combinatorics: a simplified approach for isolating insecticidal bacteria

    Microsoft Academic Search

    Phyllis A. W. Martin; Elizabeth A. Mongeon; Dawn E. Gundersen-Rindal

    2008-01-01

    Bacteria can control pest insects that damage food crops, vector diseases and defoliate trees. Conventionally, isolation of these bacteria has been from soil and sporadically from dead insects. A simplified approach for isolating insecticidal bacteria from soil using the target insect as the selective agent was employed in this study. Instead of isolating single strains of bacteria from soil and

  13. Automatic Tracking of Escherichia Coli Bacteria , Shahid Khan2 3

    E-print Network

    Central Florida, University of

    bacteria (E. coli), which can generally cause several intestinal and extra-intestinal infections of Escherichia Coli Bacteria 825 Fig. 1. (Left) A typical view of E. coli bacteria under a phase may appear as a white bulb (B). (Right) An sequence of E. coli bacteria. Among the efforts devoted

  14. Spatial and Numerical Regulation of Flagellar Biosynthesis in Polarly-Flagellated Bacteria

    PubMed Central

    2013-01-01

    Summary Control of surface organelle number and placement is a crucial aspect of the cell biology of many Gram-positive and Gram-negative bacteria, yet mechanistic insights into how bacteria spatially and numerically organize organelles are lacking. Many surface structures and internal complexes are spatially restricted in the bacterial cell (e.g., Type IV pili, holdfasts, chemoreceptors), but perhaps none show so many distinct patterns in terms of number and localization as the flagellum. In this review, we discuss two proteins, FlhF and FlhG (also annotated FleN/YlxH), which control aspects of flagellar assembly, placement, and number in polar flagellates, and may influence flagellation in some bacteria that produce peritrichous flagella. Experimental data obtained in a number of bacterial species suggest that these proteins may have acquired distinct attributes influencing flagellar assembly that reflect the diversity of flagellation patterns seen in different polar flagellates. Recent findings also suggest FlhF and FlhG are involved in other processes, such as influencing the rotation of flagella and proper cell division. Continued examination of these proteins in polar flagellates is expected to reveal how different bacteria have adapted FlhF or FlhG with specific activities to tailor flagellar biosynthesis and motility to fit the needs of each species. PMID:23600726

  15. Phenotypic and Genotypic Characterization of Some Lactic Acid Bacteria Isolated from Bee Pollen: A Preliminary Study

    PubMed Central

    BELHADJ, Hani; HARZALLAH, Daoud; BOUAMRA, Dalila; KHENNOUF, Seddik; Dahamna, Saliha; GHADBANE, Mouloud

    2014-01-01

    In the present work, five hundred and sixty-seven isolates of lactic acid bacteria were recovered from raw bee pollen grains. All isolates were screened for their antagonistic activity against both Gram-positive and Gram-negative pathogenic bacteria. Neutralized supernatants of 54 lactic acid bacteria (LAB) cultures from 216 active isolates inhibited the growth of indicator bacteria. They were phenotypically characterized, based on the fermentation of 39 carbohydrates. Using the simple matching coefficient and unweighted pair group algorithm with arithmetic averages (UPGMA), seven clusters with other two members were defined at the 79% similarity level. The following species were characterized: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Pediococcus acidilactici, Pediococcus pentosaceus, and unidentified lactobacilli. Phenotypic characteristics of major and minor clusters were also identified. Partial sequencing of the 16S rRNA gene of representative isolates from each cluster was performed, and ten strains were assigned to seven species: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Lactobacillus ingluviei, Pediococcus pentosaceus, Lactobacillus acidipiscis and Weissella cibaria. The molecular method used failed to determine the exact taxonomic status of BH0900 and AH3133. PMID:24936378

  16. [Comparative characteristics of free-living ultramicroscopical bacteria obtained from extremal biotopes].

    PubMed

    Suzina, N E; Esikova, T Z; Oleinikov, R R; Gafarov, B; Shorokhov, A P; Polivtseva, V N; Ross, D V; Abashina, T N; Duda, V I; Boronin, A M

    2015-01-01

    We isolated 50 strains of free-living ultrasmall bacteria with a cell volume that varies from 0.02 to 1.3 microm3 from a range of extremal natural biotopes, namely permafrost soils, oil slime, soils, lake silt, thermal swamp moss, and the skin integuments of the clawed frog, Xenopus laevis. Of them, 15 isolates, characterized by a cell size of less than 0.1 microm3 and a genome size from 1.5 to 2.4 Mb, were subsumed to ultramicrobacteria belonging to different philogenetic groups (Alphaproteobacteria, Bacteroidetes, Actinobacteria) and genera (Kaistia, Chryseobacterium, Microbacterium, Leucobacter, Leifsonia, and Agrococcus) of the Bacteria domain. They are free-living mesophilic heterotrophic aerobic bacteria. The representatives of Kaistia and Chryseobacterium genera were capable of facultative parasitism on other species of chemo-organotrophic bacteria and cyanobacteria. The ultramicrobacteria differed in their morpholgy, cell ultrastructural organization, and physiological and biochemical features. According to the fine structure of their cell walls, the isolates were subdivided into two groups, namely Gram-positive and Gram-negative forms. PMID:26027350

  17. Glutathione-S-Transferase Activity and Metabolism of Glutathione Conjugates by Rhizosphere Bacteria

    PubMed Central

    Zablotowicz, R. M.; Hoagland, R. E.; Locke, M. A.; Hickey, W. J.

    1995-01-01

    Glutathione-S-transferase (GST) activity was determined in 36 species of rhizosphere bacteria with the substrate 1-chloro-2,4-dinitrobenzene (CDNB) and in 18 strains with the herbicide alachlor. Highest levels of CDNB-GST activity (60 to 222 nmol (middot) h(sup-1) (middot) mg(sup-1)) were found in gram-negative bacteria: Enterobacter cloacae, Citrobacter diversus, Klebsiella planticola, Pseudomonas cepacia, Pseudomonas fluorescens, Pseudomonas putida, and Xanthomonas campestris. There was very low CDNB-GST activity in the gram-positive strains. Rapid metabolism of CDNB-glutathione conjugates, attributable to high levels of (gamma)-glutamyltranspeptidase, also occurred in the gram-negative bacteria, especially pseudomonads. Alachlor-GST activity detected in cell extracts and whole-cell suspensions of some strains of the families Enterobacteriaceae and Pseudomonaceae was 50- to 100-fold lower than CDNB-GST activity (0.5 to 2.5 nmol (middot) h(sup-1) (middot) mg(sup-1)) and was, for the most part, constitutive. The glutathione-alachlor conjugate was rarely detected. Cysteineglycine and/or cysteine conjugates were the major products of alachlor-GST metabolism. Whole-cell suspensions of certain Pseudomonas spp. dechlorinated from 20 to 75% of 100 (mu)M alachlor in 24 h. Results indicate that rhizosphere bacteria, especially fluorescent pseudomonads, may play an important role in the degradation of xenobiotics such as alachlor via GST-mediated reactions. PMID:16534956

  18. Metabolic basis for the differential susceptibility of Gram-positive pathogens to fatty acid synthesis inhibitors

    PubMed Central

    Parsons, Joshua B.; Frank, Matthew W.; Subramanian, Chitra; Saenkham, Panatda; Rock, Charles O.

    2011-01-01

    The rationale for the pursuit of bacterial type 2 fatty acid synthesis (FASII) as a target for antibacterial drug discovery in Gram-positive organisms is being debated vigorously based on their ability to incorporate extracellular fatty acids. The regulation of FASII by extracellular fatty acids was examined in Staphylococcus aureus and Streptococcus pneumoniae, representing two important groups of pathogens. Both bacteria use the same enzymatic tool kit for the conversion of extracellular fatty acids to acyl-acyl carrier protein, elongation, and incorporation into phospholipids. Exogenous fatty acids completely replace the endogenous fatty acids in S. pneumoniae but support only 50% of phospholipid synthesis in S. aureus. Fatty acids overcame FASII inhibition in S. pneumoniae but not in S. aureus. Extracellular fatty acids strongly suppress malonyl-CoA levels in S. pneumoniae but not in S. aureus, showing a feedback regulatory system in S. pneumoniae that is absent in S. aureus. Fatty acids overcame either a biochemical or a genetic block at acetyl-CoA carboxylase (ACC) in S. aureus, confirming that regulation at the ACC step is the key difference between these two species. Bacteria that possess a stringent biochemical feedback inhibition of ACC and malonyl-CoA formation triggered by environmental fatty acids are able to circumvent FASII inhibition. However, if exogenous fatty acids do not suppress malonyl-CoA formation, FASII inhibitors remain effective in the presence of fatty acid supplements. PMID:21876172

  19. Antifungal activity of strains of lactic acid bacteria isolated from a semolina ecosystem against Penicillium roqueforti, Aspergillus niger and Endomyces fibuliger contaminating bakery products

    Microsoft Academic Search

    Francesca Valerio; Mara Favilla; Palmira De Bellis; Angelo Sisto; Silvia de Candia; Paola Lavermicocca

    2009-01-01

    Thirty samples of Italian durum wheat semolina and whole durum wheat semolina, generally used for the production of Southern Italy's traditional breads, were subjected to microbiological analysis in order to explore their lactic acid bacteria (LAB) diversity and to find strains with antifungal activity. A total of 125 presumptive LAB isolates (Gram-positive and catalase-negative) were characterized by repetitive extragenic palindromic-PCR

  20. Test-kits for thiosulfate-reducing bacteria

    SciTech Connect

    Crolet, J.L. [Elf Aquitaine Production, Pau (France); Magot, M. [Elf Aquitaine Group, Labege (France); Brazy, J.L. [Elf Congo, Pointe Noire (Congo)

    1997-08-01

    API or proprietary test-kits presently used for the detection of bacteria involved in microbial corrosion are designed for specific detection of sulfate-reducing bacteria (SRB). It was recently shown that other sulfidogenic bacteria such as thiosulfate-reducing bacteria (TRB) are also involved in the corrosion of carbon steel. Since these bacteria cannot be detected by SRB test-kits, a new kit was developed for TRB detection, and validated in field trials.

  1. Using Fluorescent Viruses for Detecting Bacteria in Water

    NASA Technical Reports Server (NTRS)

    Tabacco, Mary Beth; Qian, Xiaohua; Russo, Jaimie A.

    2009-01-01

    A method of detecting water-borne pathogenic bacteria is based partly on established molecular-recognition and fluorescent-labeling concepts, according to which bacteria of a species of interest are labeled with fluorescent reporter molecules and the bacteria can then be detected by fluorescence spectroscopy. The novelty of the present method lies in the use of bacteriophages (viruses that infect bacteria) to deliver the fluorescent reporter molecules to the bacteria of the species of interest.

  2. Method of Detecting Coliform Bacteria and Escherichia Coli Bacteria from Reflected Light

    NASA Technical Reports Server (NTRS)

    Vincent, Robert (Inventor)

    2013-01-01

    The present invention relates to a method of detecting coliform bacteria in water from reflected light and a method of detecting Eschericha Coli bacteria in water from reflected light, and also includes devices for the measurement, calculation and transmission of data relating to that method.

  3. Dynamics of Gram-negative bacteria population density in a soil in the course of the succession initiated by chitin and cellulose

    NASA Astrophysics Data System (ADS)

    Konstantin, Ivanov; Lubov, Polyanskaya

    2014-05-01

    The functions of actinomycetes in polymer destruction in soil traditionally considered as the dominant, compare to another groups of bacteria. Gram-positive bacteria also have ecological functions in destruction of soil organic matter. The role of Gram-negative bacteria has been researched in the microbial succession in terms of polymers destruction, which are widely spreads in soils: chitin and cellulose. The method with nalidixic acid as an inhibitor of DNA division of Gram-negative bacteria was modified. By modified method microbial succession of Gram-negative bacteria in the different horizons of a chernozem under aerobic and anaerobic conditions was researched. Chitin and cellulose as the source of nutrients with moistening was used in experiments. The introduction of chitin had no positive effect on the population density of Gram-negative bacteria in a chernozem, but it advanced the date of their appearance in microbial succession: the maximum of Gram-negative bacteria population density was registered on the 3rd- 7th day of the experiment with adding chitin. Compare to the control, which one was without any nutrient adding this dynamics registered much earlier. Consequently, the introduction of chitin as an additional source of nutrition promoted revealing of the Gram-negative bacteria in soil already at the early stages of the succession. In the course of the succession, when the fungal mycelium begins to die off, the actinomycetic mycelium increases in length, i.e., Gram-negative bacteria are replaced at this stage with Gram-positive ones, the leading role among which belongs to actinomycetes. The growth rate of Gram-negative bacteria is higher than that of actinomycetes, so they start chitin utilization at the early stages of the succession, whereas actinomycetes dominate at the late stages. The population density of Gram-negative bacteria was lower under the anaerobic conditions as compared with that in the aerobic ones. The population density of Gram-negative bacteria in the lower layer of the A horizon of the chernozem and in the B horizon was slightly higher only in the case of the chitin introduction. When cellulose was introduced into the soil under aerobic conditions, the population density of Gram-negative bacteria in all the layers of the A horizon of the chernozem was maximal from the 14th to the 22nd day of the experiment. Simultaneously, an increase in the length of the actinomycetal mycelium was observed, as these organisms also perform cellulose hydrolysis in soils. The Gram-negative bacteria began to develop at the stage of the fungal mycelium destruction, which indirectly confirmed the chitinolytic activity of these bacteria.

  4. In vitro antibacterial potency of Butea monosperma Lam. against 12 clinically isolated multidrug resistant bacteria

    PubMed Central

    Sahu, Mahesh Chandra; Padhy, Rabindra Nath

    2013-01-01

    Objective To investigate the antibacterial activity, using cold and hot extraction procedures with five solvents, petroleum ether, acetone, ethanol, methanol and water to validate medicinal uses of Butea monosperma Lam (B. monosperma) in controlling infections; and to qualitatively estimate phytochemical constituents of leaf-extracts of the plant. Methods The antibacterial activity of leaf-extracts was evaluated by the agar-well diffusion method against clinically isolated 12 Gram-positive and -negative multidrug resistant (MDR) pathogenic bacteria in vitro. Values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of leaf-extracts against each bacterium were obtained in a 96-well micro-titre plate, by broth dilution micro-titre plate technique. Results The presence of tannins, flavonoids, starch, glycosides and carbohydrates in different leaf extracts was established. Pathogenic bacteria used were, Acinetobacter sp., Chromobacterium violaceum, Citrobacter freundii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Shigella sp., Enterococcus sp., Staphylococcus aureus (S. aureus), methicillin resistant S. aureus and vancomycin resistant S. aureus, along with standard bacterial strains. These MDR bacteria had been recorded to have significant inhibitions by leaf extracts, obtained by cold and hot extraction procedures with five solvents. In addition, the hot aqueous extract against Enterococcus sp. had the highest inhibition zone-size (21 mm). Ciprofloxacin 30 µg/disc was the positive/reference control and the diluting solvent, 10% dimethyl sulphoxide was the negative control. Recorded MIC values of different extracts ranged between 0.23 and 13.30 mg/mL, and MBC values were 0.52 to 30.00 mg/mL, for these bacteria. Conclusions Leaf-extracts with hot water and ethanol had shown significant antibacterial activity against all bacteria. B. monosperma leaf-extract could be used in treating infectious diseases, caused by the range of tested bacteria, as complementary and alternate medicine.

  5. Chemotactic selection of pollutant degrading soil bacteria

    DOEpatents

    Hazen, Terry C. (Augusta, GA)

    1994-01-01

    A method for identifying soil microbial strains which may be bacterial degraders of pollutants comprising the steps of 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, collecting the contents of the container, and 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 inoculate 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.

  6. Single bacteria identification by Raman spectroscopy.

    PubMed

    Strola, Samy Andrea; Baritaux, Jean-Charles; Schultz, Emmanuelle; Simon, Anne Catherine; Allier, Cédric; Espagnon, Isabelle; Jary, Dorothée; Dinten, Jean-Marc

    2014-01-01

    We report on rapid identification of single bacteria using a low-cost, compact, Raman spectroscope. We demonstrate that a 60-s procedure is sufficient to acquire a comprehensive Raman spectrum in the range of 600 to 3300 cm?¹. This time includes localization of small bacteria aggregates, alignment on a single individual, and spontaneous Raman scattering signal collection. Fast localization of small bacteria aggregates, typically composed of less than a dozen individuals, is achieved by lensfree imaging over a large field of view of 24 mm². The lensfree image also allows precise alignment of a single bacteria with the probing beam without the need for a standard microscope. Raman scattered light from a 34-mW continuous laser at 532 nm was fed to a customized spectrometer (prototype Tornado Spectral Systems). Owing to the high light throughput of this spectrometer, integration times as low as 10 s were found acceptable. We have recorded a total of 1200 spectra over seven bacterial species. Using this database and an optimized preprocessing, classification rates of ~90% were obtained. The speed and sensitivity of our Raman spectrometer pave the way for high-throughput and nondestructive real-time bacteria identification assays. This compact and low-cost technology can benefit biomedical, clinical diagnostic, and environmental applications. PMID:25028774

  7. Single bacteria identification by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Strola, Samy Andrea; Baritaux, Jean-Charles; Schultz, Emmanuelle; Simon, Anne Catherine; Allier, Cédric; Espagnon, Isabelle; Jary, Dorothée; Dinten, Jean-Marc

    2014-11-01

    We report on rapid identification of single bacteria using a low-cost, compact, Raman spectroscope. We demonstrate that a 60-s procedure is sufficient to acquire a comprehensive Raman spectrum in the range of 600 to 3300. This time includes localization of small bacteria aggregates, alignment on a single individual, and spontaneous Raman scattering signal collection. Fast localization of small bacteria aggregates, typically composed of less than a dozen individuals, is achieved by lensfree imaging over a large field of view of 24. The lensfree image also allows precise alignment of a single bacteria with the probing beam without the need for a standard microscope. Raman scattered light from a 34-mW continuous laser at 532 nm was fed to a customized spectrometer (prototype Tornado Spectral Systems). Owing to the high light throughput of this spectrometer, integration times as low as 10 s were found acceptable. We have recorded a total of 1200 spectra over seven bacterial species. Using this database and an optimized preprocessing, classification rates of ˜90% were obtained. The speed and sensitivity of our Raman spectrometer pave the way for high-throughput and nondestructive real-time bacteria identification assays. This compact and low-cost technology can benefit biomedical, clinical diagnostic, and environmental applications.

  8. Diversity of endophytic bacteria in Brazilian sugarcane.

    PubMed

    Magnani, G S; Didonet, C M; Cruz, L M; Picheth, C F; Pedrosa, F O; Souza, E M

    2010-01-01

    Endophytic bacteria live inside plant tissues without causing disease. Studies of endophytes in sugarcane have focused on the isolation of diazotrophic bacteria. We examined the diversity of endophytic bacteria in the internal tissues of sugarcane stems and leaves, using molecular and biochemical methods. Potato-agar medium was used to cultivate the endophytes; 32 isolates were selected for analysis. DNA was extracted and the 16S rRNA gene was partially sequenced and used for molecular identification. Gram staining, catalase and oxidase tests, and the API-20E system were used to characterize the isolates. The strains were divided into five groups, based on the 16S rRNA sequences. Group I comprised 14 representatives of the Enterobacteriaceae; group II was composed of Bacilli; group III contained one representative, Curtobacterium sp; group IV contained representatives of the Pseudomonadaceae family, and group V had one isolate with an uncultured bacterium. Four isolates were able to reduce acetylene to ethylene. Most of the bacteria isolated from the sugarcane stem and leaf tissues belonged to Enterobacteriaceae and Pseudomonaceae, respectively, demonstrating niche specificity. Overall, we found the endophytic bacteria in sugarcane to be more diverse than previously reported. PMID:20198580

  9. Comparative genomic analysis of T-box regulatory systems in bacteria.

    PubMed

    Vitreschak, Alexey G; Mironov, Andrei A; Lyubetsky, Vassily A; Gelfand, Mikhail S

    2008-04-01

    T-box antitermination is one of the main mechanisms of regulation of genes involved in amino acid metabolism in Gram-positive bacteria. T-box regulatory sites consist of conserved sequence and RNA secondary structure elements. Using a set of known T-box sites, we constructed the common pattern and used it to scan available bacterial genomes. New T-boxes were found in various Gram-positive bacteria, some Gram-negative bacteria (delta-proteobacteria), and some other bacterial groups (Deinococcales/Thermales, Chloroflexi, Dictyoglomi). The majority of T-box-regulated genes encode aminoacyl-tRNA synthetases. Two other groups of T-box-regulated genes are amino acid biosynthetic genes and transporters, as well as genes with unknown function. Analysis of candidate T-box sites resulted in new functional annotations. We assigned the amino acid specificity to a large number of candidate amino acid transporters and a possible function to amino acid biosynthesis genes. We then studied the evolution of the T-boxes. Analysis of the constructed phylogenetic trees demonstrated that in addition to the normal evolution consistent with the evolution of regulated genes, T-boxes may be duplicated, transferred to other genes, and change specificity. We observed several cases of recent T-box regulon expansion following the loss of a previously existing regulatory system, in particular, arginine regulon in Clostridium difficile and methionine regulon in Lactobacillaceae. Finally, we described a new structural class of T-boxes containing duplicated terminator-antiterminator elements and unusual reduced T-boxes regulating initiation of translation in the Actinobacteria. PMID:18359782

  10. Direct identification of bacteria from positive BacT/ALERT blood culture bottles using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry.

    PubMed

    Mestas, Javier; Felsenstein, Susanna; Bard, Jennifer Dien

    2014-11-01

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is a fast and robust method for the identification of bacteria. In this study, we evaluate the performance of a laboratory-developed lysis method (LDT) for the rapid identification of bacteria from positive BacT/ALERT blood culture bottles. Of the 168 positive bottles tested, 159 were monomicrobial, the majority of which were Gram-positive organisms (61.0% versus 39.0%). Using a cut-off score of ?1.7, 80.4% of the organisms were correctly identified to the species level, and the identification rate of Gram-negative organisms (90.3%) was found to be significantly greater than that of Gram-positive organisms (78.4%). The simplicity and cost-effectiveness of the LDT enable it to be fully integrated into the routine workflow of the clinical microbiology laboratory, allowing for rapid identification of Gram-positive and Gram-negative bacteria within an hour of blood culture positivity. PMID:25139844

  11. Antimicrobial activity of polyphenol-rich fractions from Sida alba L. (Malvaceae) against co-trimoxazol-resistant bacteria strains

    PubMed Central

    2012-01-01

    Background The increased resistance of microorganisms to the currently used antimicrobials has lead to the evaluation of other agents that might have antimicrobial activity. Medicinal plants are sources of phytochemicals which are able to initiate different biological activities including antimicrobials Materials and methods In vitro antibacterial (MIC, MBC and time-kill studies) of polyphenol-rich fractions from Sida alba L. (Malvaceae) was assessed using ten bacteria strains (Gram-negative and Gram-positive). Results All test bacteria were susceptible to the polyphenol-rich fractions. Time-kill results showed that after 5 h exposition there was no viable microorganism in the initial inoculum and the effect of polyphenol-rich fractions was faster on Enterococcus faecalis (Gram-positive bacterium) comparatively to the other bacteria strains. Conclusion The data analysis indicates that the tested of polyphenol-rich fractions has significant effects when compared with the standard antibiotic. These results therefore justify the traditional use of sida alba L., alone or in combination with other herbs to treat bacterial infections. PMID:22364123

  12. 27/05/2012 21:13Fighting bacteria?s strength in numbers | Britney Spears New Video Page 1 of 2http://britneyspearsnewvideo.fruntrunnazproductions.com/194/fighting-bacterias-strength-in-numbers/

    E-print Network

    West, Stuart

    27/05/2012 21:13Fighting bacteria?s strength in numbers | Britney Spears New Video Page 1 of 2http://britneyspearsnewvideo.fruntrunnazproductions.com/194/fighting-bacterias-strength-in-numbers/ Home Britney Spears New Video Fighting bacteria?s strength infections by proving a long-held theory about how bacteria communicate with each other. Researchers

  13. Cardiolipin, ?- d-glucopyranosyl, and l-lysylcardiolipin from Gram-positive bacteria: FAB MS, monofilm and X-ray powder diffraction studies

    Microsoft Academic Search

    T. Gutberlet; U. Dietrich; H. Bradaczek; G. Pohlentz; K. Leopold; W. Fischer

    2000-01-01

    Cardiolipin preparations from Streptococcus B, Listeria welshimeri, Staphylococcus aureus, and a glucosyl and lysyl derivative of cardiolipin were analysed for fatty acid composition and fatty acid combinations. Three different fatty acid patterns are described and up to 17 molecular species were identified in Streptococcus B lipids by high resolution FAB MS. The physicochemical properties of these lipids were characterised in

  14. In vitro activities of antimicrobial cationic peptides; melittin and nisin, alone or in combination with antibiotics against Gram-positive bacteria.

    PubMed

    Dosler, Sibel; Gerceker, A Alev

    2012-06-01

    The In vitro activities of two antimicrobial cationic peptides, melittin and nisin alone and in combination with frequently used antibiotics (daptomycin, vancomycin, linezolid, ampicillin, and erythromycin), were assessed against clinical isolates of methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus and Enterococcus faecalis. Using the broth microdilution method, minimum inhibitory concentration (MIC) ranges of melittin and nisin against all strains were 2-8 ?g/ml and 2-32 ?g/ml respectively. In combination studies performed with the microdilution checkerboard method using a fractional inhibitory concentration index of ? 0.5 as borderline, synergistic interactions occurred more frequently with nisin-ampicillin combination against MSSA and nisin-daptomycin combination against E. faecalis strains. The results of the time-killing curve analysis demonstrated that the concentration dependent rapid bactericidal activity of nisin, and that synergism or early synergism was detected in most strains when nisin or melittin was used in combination with antibiotics even at concentrations of 0.5 × MIC. PMID:22759757

  15. Results of a Double-Blind, Randomized Trial of Ceftobiprole Treatment of Complicated Skin and Skin Structure Infections Caused by Gram-Positive Bacteria

    Microsoft Academic Search

    Gary J. Noel; Richard S. Strauss; Karen Amsler; Markus Heep; Rienk Pypstra; Joseph S. Solomkin

    2008-01-01

    Ceftobiprole is the first broad-spectrum cephalosporin with activity against methicillin-resistant Staphylo- coccus aureus (MRSA) to be assessed in late-stage clinical trials. As a pivotal step in the clinical development of ceftobiprole, a multicenter, global, randomized, double-blind trial was conducted to compare the efficacy of ceftobiprole to that of vancomycin in patients with complicated skin and skin structure infections (cSSSIs) caused

  16. Methylation of halogenated phenols and thiophenols by cell extracts of gram-positive and gram-negative bacteria. [Rhodococcus sp. ; Pseudomonas sp. ; Acinetobacter sp

    SciTech Connect

    Neilson, A.H.; Lindgren, C.; Hynning, P.A.; Remberger, M.

    1988-02-01

    O-methylation of 2,6-dibromophenol was studied in cell extracts prepared from Rhodococcus sp. strain 1395. O-methylation activity was also demonstrated in extracts from two other Rhodococcus sp. strains, an Acinetobacter sp. strain, and a Pseudomonas sp. strain. A diverse range of chloro- and bromophenols, chlorothiophenols, chloro- and bromoguaiacols, and chloro- and bromocatechols were assayed as the substrates by using extracts prepared from strain 1395; all of the compounds were methylated to the corresponding anisoles, veratroles, or guaiacols. The specific activity of the enzyme towards the thiophenols was significantly higher than it was towards all the other substrates-high activity was found with pentafluorothiophenol, although the activity with pentafluorophenol was undetectable with the incubation times used. For the chlorophenols, the position of the substituents was of cardinal importance. The enzyme had higher activity towards the halogenated catechols than towards the corresponding guaiacols, and selective O-methylation of the 3,4,5-trihalogenocatechols yielded predominantly the 3,4,5-trihalogenoguaiacols. Neither 2,4-dinitrophenol, hexachlorophene, nor 5-chloro- or 5-bromovanillin was O-methylated. The results showed conclusively that the methylation reactions were enzymatic and confirmed the conclusion from extensive studies using whole cells that methylation of halogenated phenols may be a significant alternative to biodegradation.

  17. 3,5-Dioxopyrazolidines, Novel Inhibitors of UDP-N- Acetylenolpyruvylglucosamine Reductase (MurB) with Activity against Gram-Positive Bacteria

    Microsoft Academic Search

    Youjun Yang; Anatoly Severin; Rajiv Chopra; Girija Krishnamurthy; Guy Singh; William Hu; David Keeney; Kristine Svenson; Peter J. Petersen; Pornpen Labthavikul; David M. Shlaes; Beth A. Rasmussen; Amedeo A. Failli; Jay S. Shumsky; Kristina M. K. Kutterer; Adam Gilbert; Tarek S. Mansour

    2006-01-01

    A series of 3,5-dioxopyrazolidines was identified as novel inhibitors of UDP-N-acetylenolpyruvylglucosamine reductase (MurB). Compounds 1 to 3, which are 1,2-bis(4-chlorophenyl)-3,5-dioxopyrazolidine-4-carbox- amides, inhibited Escherichia coli MurB, Staphyloccocus aureus MurB, and E. coli MurA with 50% inhibitory concentrations (IC50s) in the range of 4.1 to 6.8 M, 4.3 to 10.3 M, and 6.8 to 29.4 M, respectively. Compound 4, a C-4-unsubstituted 1,2-bis(3,4-dichlorophenyl)-3,5-dioxopyrazolidine,

  18. Correlation between Vancomycin MIC Values and Those of Other Agents against Gram-Positive Bacteria among Patients with Bloodstream Infections Caused by Methicillin-Resistant Staphylococcus aureus ?

    PubMed Central

    Patel, N.; Lubanski, P.; Ferro, S.; Bonafede, M.; Harrington, S.; Evans, A.; Stellrecht, K.; Lodise, T. P.

    2009-01-01

    An increase in the distribution of vancomycin MIC values among methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) isolates has been noted. It is postulated that the shift in vancomycin MIC values may be associated with a concurrent rise in the MIC values of other anti-MRSA agents. Scant data are available on the correlation between vancomycin MIC values and the MIC values of other anti-MRSA agents. This study examined the correlation between vancomycin MIC values and the MIC values of daptomycin, linezolid, tigecycline, and teicoplanin among 120 patients with bloodstream infections caused by MRSA at a tertiary care hospital between January 2005 and May 2007. For each included patient, the MIC values of the antibiotics under study were determined by the Etest method and were separated into the following two categories: day 1 (index) and post-day 1 (subsequent). For subsequent isolates, the MIC values for each antibiotic from the post-day 1 terminal isolate were used. Among the index isolates, there was a significant correlation (P value, <0.01) between the MIC values for vancomycin and daptomycin and between the MIC values for vancomycin and teicoplanin. The MIC values for daptomycin were significantly correlated with linezolid, tigecycline, and teicoplanin MIC values. Among the 48 patients with subsequent isolates, vancomycin MIC values were significantly correlated with MIC values for daptomycin, linezolid, and teicoplanin (? value of ?0.38 for all comparisons). This study documented an association between vancomycin MIC values and the MIC values of other anti-MRSA antibiotics among patients with bloodstream infections caused by MRSA primarily treated with vancomycin. PMID:19805558

  19. Correlation between vancomycin MIC values and those of other agents against gram-positive bacteria among patients with bloodstream infections caused by methicillin-resistant Staphylococcus aureus.

    PubMed

    Patel, N; Lubanski, P; Ferro, S; Bonafede, M; Harrington, S; Evans, A; Stellrecht, K; Lodise, T P

    2009-12-01

    An increase in the distribution of vancomycin MIC values among methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) isolates has been noted. It is postulated that the shift in vancomycin MIC values may be associated with a concurrent rise in the MIC values of other anti-MRSA agents. Scant data are available on the correlation between vancomycin MIC values and the MIC values of other anti-MRSA agents. This study examined the correlation between vancomycin MIC values and the MIC values of daptomycin, linezolid, tigecycline, and teicoplanin among 120 patients with bloodstream infections caused by MRSA at a tertiary care hospital between January 2005 and May 2007. For each included patient, the MIC values of the antibiotics under study were determined by the Etest method and were separated into the following two categories: day 1 (index) and post-day 1 (subsequent). For subsequent isolates, the MIC values for each antibiotic from the post-day 1 terminal isolate were used. Among the index isolates, there was a significant correlation (P value, <0.01) between the MIC values for vancomycin and daptomycin and between the MIC values for vancomycin and teicoplanin. The MIC values for daptomycin were significantly correlated with linezolid, tigecycline, and teicoplanin MIC values. Among the 48 patients with subsequent isolates, vancomycin MIC values were significantly correlated with MIC values for daptomycin, linezolid, and teicoplanin (rho value of >or=0.38 for all comparisons). This study documented an association between vancomycin MIC values and the MIC values of other anti-MRSA antibiotics among patients with bloodstream infections caused by MRSA primarily treated with vancomycin. PMID:19805558

  20. Isolation and Purification of Enteroicin E-760 with a Broad Antimicrobial Activity Against Gram-positive and Gram-negative Bacteria (AAC01569-06 Version 3)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Strain NRRL B-30745, isolated from chicken ceca, and identified as an Enterococcus spp. of the durans/faecium/hirae group, produces a 5362 Da bacteriocin that inhibits the growth of Salmonella enteritidis, S. choleraesuis, S. typhimurium, S. gallinarum, Escherichia coli O157:H7, Yersinia enterocolit...

  1. Aerobic Gram-Positive and Gram-Negative Bacteria Exhibit Differential Sensitivity to and Transformation of 2,4,6Trinitrotoluene (TNT)

    Microsoft Academic Search

    Mark E. Fuller

    1997-01-01

    .   A systematic evaluation of the ability of different bacterial genera to transform 2,4,6-trinitrotoluene (TNT), and grow in\\u000a its presence, was conducted. Aerobic Gram-negative organisms degraded TNT and evidenced net consumption of reduced metabolites\\u000a when cultured in molasses medium. Some Gram-negative isolates transformed all the initial TNT to undetectable metabolites,\\u000a with no adsorption of TNT or metabolites to cells. Growth

  2. Immunological crossreactivity to the catabolite control protein CcpA from Bacillus megaterium is found in many Gram-positive bacteria

    Microsoft Academic Search

    Elke Küster; Evert J. Luesink; Willem M. de Vos; Wolfgang Hillen

    1996-01-01

    The catabolite control protein CcpA from Bacillus megaterium was overproduced as a fusion protein to a 6xhis affinity tag and purified to homogeneity. Polyclonal antibodies of high affinity and specificity were raised against the purified protein. The serum did not crossreact with purified Lac repressor despite the fact that CcpA and LacI belong to the same protein family. Using this

  3. Mortality of fecal bacteria in seawater

    SciTech Connect

    Garcia-Lara, J.; Menon, P.; Servais, P.; Billen, G. (Univ. Libre de Bruxelles, Brussels (Belgium))

    1991-03-01

    The authors propose a method for determining the mortality rate for allochthonous bacteria released in aquatic environments without interference due to the loss of culturability in specific culture media. This method consists of following the disappearance of radioactivity from the trichloracetic acid-insoluble fraction in water samples to which ({sup 3}H)thymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, they found that the actual rate of disappearance of fecal bacteria was 1 order of magnitude lower than the rate of loss of culturability on specific media. Minor adaptation of the procedure may facilitate assessment of the effect of protozoan grazing and bacteriophage lysis on the overall bacterial mortality rate.

  4. Bacteria-phage interactions in natural environments.

    PubMed

    Díaz-Muñoz, Samuel L; Koskella, Britt

    2014-01-01

    Phages are considered the most abundant and diverse biological entities on Earth and are notable not only for their sheer abundance, but also for their influence on bacterial hosts. In nature, bacteria-phage relationships are complex and have far-reaching consequences beyond particular pairwise interactions, influencing everything from bacterial virulence to eukaryotic fitness to the carbon cycle. In this review, we examine bacteria and phage distributions in nature first by highlighting biogeographic patterns and nonhost environmental influences on phage distribution, then by considering the ways in which phages and bacteria interact, emphasizing phage life cycles, bacterial responses to phage infection, and the complex patterns of phage host specificity. Finally, we discuss phage impacts on bacterial abundance, genetics, and physiology, and further aim to clarify distinctions between current theoretical models and point out areas in need of future research. PMID:25131402

  5. Living Without Oxygen: Oxygen Tolerance in Bacteria

    NSDL National Science Digital Library

    Sharon Harris

    This activity focuses on chemical processes, such as nitrogen fixation and denitrification, which are carried out by bacteria. Often the efficacy of these processes is determined by the amount of oxygen present in the environment in which the bacteria live. Much of the time, these processes are carried out by facultatively anaerobic bacteria in the suboxic region of lakes, oceans, sediments, and leaf litter. Students will discover whether facultatively anaerobic photoautotrophs share the same tolerance for oxygen, how differences in oxygen tolerance can be tested, and of what significance the tolerance for oxygen is in the nitrogen cycle. They will practice aseptic technique, monitor the growth of bacterial cultures, display their results graphically, and propose environmental problems associated with the oxygen tolerance of nitrogen fixers and denitifiers.

  6. Copper tolerance and virulence in bacteria.

    PubMed

    Ladomersky, Erik; Petris, Michael J

    2015-06-10

    Copper (Cu) is an essential trace element for all aerobic organisms. It functions as a cofactor in enzymes that catalyze a wide variety of redox reactions due to its ability to cycle between two oxidation states, Cu(i) and Cu(ii). This same redox property of copper has the potential to cause toxicity if copper homeostasis is not maintained. Studies suggest that the toxic properties of copper are harnessed by the innate immune system of the host to kill bacteria. To counter such defenses, bacteria rely on copper tolerance genes for virulence within the host. These discoveries suggest bacterial copper intoxication is a component of host nutritional immunity, thus expanding our knowledge of the roles of copper in biology. This review summarizes our current understanding of copper tolerance in bacteria, and the extent to which these pathways contribute to bacterial virulence within the host. PMID:25652326

  7. Responses of bark beetle-associated bacteria to host monoterpenes and their relationship to insect life histories.

    PubMed

    Adams, Aaron S; Boone, Celia K; Bohlmann, Jörg; Raffa, Kenneth F

    2011-08-01

    Bark beetles that colonize living conifers and their microbial associates encounter constitutive and induced chemical defenses of their host. Monoterpene hydrocarbons comprise a major component of these allelochemicals, and many are antibiotic to insects, fungi, and bacteria. Some bark beetle species exhaust these defenses by killing their host through mass attacks mediated by aggregation pheromones. Others lack adult aggregation pheromones and do not engage in pheromone-mediated mass attacks, but rather have the ability to complete development within live hosts. In the former species, the larvae develop in tissue largely depleted of host terpenes, whereas in the latter exposure to these compounds persists throughout development. A substantial literature exists on how monoterpenes affect bark beetles and their associated fungi, but little is known of how they affect bacteria, which in turn can influence beetle performance in various manners. We tested several bacteria from two bark beetle species for their ability to grow in the presence of a diversity of host monoterpenes. Bacteria were isolated from the mountain pine beetle, Dendroctonus ponderosae Hopkins, which typically kills trees during colonization, and the red turpentine beetle, Dendroctonus valens LeConte, which often lives in their host without causing mortality. Bacteria from D. ponderosae were gram-positive Actinobacteria and Bacilli; one yeast also was tested. Bacteria from D. valens were Actinobacteria, Bacilli, and ?-Proteobacteria. Bacteria from D. valens were more tolerant of monoterpenes than were those from D. ponderosae. Bacteria from D. ponderosae did not grow in the presence of ?-pinene and 3-carene, and grew in, but were inhibited by, ?-pinene and ?-phellandrene. Limonene and myrcene had little inhibitory effect on bacteria from either beetle species. Tolerance to these antibiotic compounds appears to have resulted from adaptation to living in a terpene-rich environment. PMID:21710365

  8. Gastric spiral bacteria in small felids.

    PubMed

    Kinsel, M J; Kovarik, P; Murnane, R D

    1998-06-01

    Nine small cats, including one bobcat (Felis rufus), one Pallas cat (F. manul), one Canada lynx (F. lynx canadensis), two fishing cats (F. viverrina), two margays (F. wiedii), and two sand cats (F. margarita), necropsied between June 1995 and March 1997 had large numbers of gastric spiral bacteria, whereas five large cats, including one African lion (Panthera leo), two snow leopards (P. uncia), one Siberian tiger (P. tigris altaica), and one jaguar (P. onca), necropsied during the same period had none. All of the spiral organisms from the nine small cats were histologically and ultrastructurally similar. Histologically, the spiral bacteria were 5-14 microm long with five to nine coils per organism and were located both extracellularly within gastric glands and surface mucus, and intracellularly in parietal cells. Spiral bacteria in gastric mucosal scrapings from the Canada lynx, one fishing cat, and the two sand cats were gram negative and had corkscrewlike to tumbling motility when viewed with phase contrast microscopy. The bacteria were 0.5-0.7 microm wide, with a periodicity of 0.65-1.1 microm in all cats. Bipolar sheathed flagella were occasionally observed, and no periplasmic fibrils were seen. The bacteria were extracellular in parietal cell canaliculi and intracellular within parietal cells. Culture of mucosal scrapings from the Canada lynx and sand cats was unsuccessful. Based on morphology, motility, and cellular tropism, the bacteria were probably Helicobacter-like organisms. Although the two margays had moderate lymphoplasmacytic gastritis, the other cats lacked or had only mild gastric lymphoid infiltrates, suggesting that these organisms are either commensals or opportunistic pathogens. PMID:9732040

  9. In Vitro and In Vivo Antibacterial Activities of Heteroaryl Isothiazolones against Resistant Gram-Positive Pathogens?

    PubMed Central

    Pucci, Michael J.; Cheng, Jijun; Podos, Steven D.; Thoma, Christy L.; Thanassi, Jane A.; Buechter, Douglas D.; Mushtaq, Gohar; Vigliotti, Gerald A.; Bradbury, Barton J.; Deshpande, Milind

    2007-01-01

    The activities of several tricyclic heteroaryl isothiazolones (HITZs) against an assortment of gram-positive and gram-negative clinical isolates were assessed. These compounds target bacterial DNA replication and were found to possess broad-spectrum activities especially against gram-positive strains, including antibiotic-resistant staphylococci and streptococci. These included methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-nonsusceptible staphylococci, and quinolone-resistant strains. The HITZs were more active than the comparator antimicrobials in most cases. For gram-negative bacteria, the tested compounds were less active against members of the family Enterobacteriaceae but showed exceptional potencies against Haemophilus influenzae, Moraxella catarrhalis, and Neisseria spp. Good activity against several anaerobes, as well as Legionella pneumophila and Mycoplasma pneumoniae, was also observed. Excellent bactericidal activity against staphylococci was observed in time-kill assays, with an approximately 3-log drop in the numbers of CFU/ml occurring after 4 h of exposure to compound. Postantibiotic effects (PAEs) of 2.0 and 1.7 h for methicillin-susceptible S. aureus and MRSA strains, respectively, were observed, and these were similar to those seen with moxifloxacin at 10× MIC. In vivo efficacy was demonstrated in murine infections by using sepsis and thigh infection models. The 50% protective doses were ?1 mg/kg of body weight against S. aureus in the sepsis model, while decreases in the numbers of CFU per thigh equal to or greater than those detected in animals treated with a standard dose of vancomycin were seen in the animals with thigh infections. Pharmacokinetic analyses of treated mice indicated exposures similar to those to ciprofloxacin at equivalent dose levels. These promising initial data suggest further study on the use of the HITZs as antibacterial agents. PMID:17242152

  10. Degradation of monomethylhydrazine by two soil bacteria

    SciTech Connect

    Ou, L.T.

    1988-12-01

    It has been reported that three heterotrophic soil bacteria had the capacity to degrade hydrazine. One of these organisms, Achromobacter sp., degraded hydrazine to N/sub 2/ gas. Furthermore, it was reported that monomethylhydrazine (MMH) in Arredondo fine sand was mineralized to CO/sub 2/, and that such degradation is microbial. However, microorganisms that degrade MMH have not been reported. MMH and hydrazine are chemically similar to one another. Therefore, this study was initiated to test the capacity of the two hydrazine-degrading bacteria, Achromobacter sp. and Pseudomonas sp., to degrade MMH.

  11. Bacteria Provide Cleanup of Oil Spills, Wastewater

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Through Small Business Innovation Research (SBIR) contracts with Marshall Space Flight Center, Micro-Bac International Inc., of Round Rock, Texas, developed a phototrophic cell for water purification in space. Inside the cell: millions of photosynthetic bacteria. Micro-Bac proceeded to commercialize the bacterial formulation it developed for the SBIR project. The formulation is now used for the remediation of wastewater systems and waste from livestock farms and food manufacturers. Strains of the SBIR-derived bacteria also feature in microbial solutions that treat environmentally damaging oil spills, such as that resulting from the catastrophic 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico.

  12. Amplification of Signaling Events in Bacteria

    NSDL National Science Digital Library

    Frederick W. Dahlquist (University of Oregon; Knight Professor and Head, Department of Chemistry, Member, Institute of Molecular Biology REV)

    2002-05-14

    Bacteria respond to extremely shallow chemical gradients by modifying their motility in a process called chemotaxis. This chemotactic response is characterized by high sensitivity to small concentration differences, which extends over a large range of concentrations. This combination of high signal gain and large dynamic range results from both a memory of past events and the ability to amplify small differences in signal between the memory and the current environment. Dahlquist describes the signaling mechanism used by bacteria to regulate the flagellar motor and the places in this pathway where signal amplification may occur.

  13. Flavones with antibacterial activity against cariogenic bacteria

    Microsoft Academic Search

    Masaru Sato; Shuu Fujiwara; Hironori Tsuchiya; Teruhisa Fujii; Munekazu Iinuma; Hideki Tosa; Yasutoshi Ohkawa

    1996-01-01

    Methanolic extracts obtained from 13 plants were studied for their antibacterial activity against cariogenic bacteria. Among them, the extract from Artocarpus heterophyllus showed the most intensive activity. Serial chromatographic purifications offered two active compounds which were identified as 6-(3-methyl-1-butenyl)-5,2?,4?-trihydroxy-3-isoprenyl-7-methoxyflavone and 5,7,2?,4?-tetrahydroxy-6-isoprenylflavone. Both isolates completely inhibited the growth of primary cariogenic bacteria at 3.13–12.5 ?g\\/ml. They also exhibited the growth inhibitory

  14. Mechanical properties of hexadecane-water interfaces with adsorbed hydrophobic bacteria

    NASA Astrophysics Data System (ADS)

    Kang, Zhewen

    Certain strains of hydrophobic bacteria are known to play critical roles in petroleum-related applications. The aim of this study was to investigate how hydrophobic bacteria in their stationary phase could adsorb onto the hexadecane-water interface and alter its mechanical properties. The two strains of bacteria used in forming the interfacial films were Acinetobacter venetianus RAG-1 (a Gram-negative bacterium) and Rhodococcus erythropolis 20S-E1-c (Gram-positive). Experiments at two different length scales (millimetre and micrometre) were conducted and the results were compared. In addition, a simple flow experiment was designed in a constricted channel and the results were related to the intrinsic mechanical properties of bacteria-adsorbed films. On the millimetre scale, using the pendant drop technique, the film interfacial tension was monitored as the surface area was made to undergo changes. Under static conditions, both types of bacteria showed no significant effect on the interfacial tension. When subjected to transient excitations, the two bacterial films exhibited qualitatively similar, yet quantitative distinct rheological properties (including film elasticities and relaxation times). Under continuous reduction of surface area, the RAG-1 system showed a "paper-like" interface, while the interface of the 20S-E1-c system was "soap film-like." These macroscopic observations could be explained by the surface ultrastructures of the two cell strains. On the micrometre scale, using the micropipette technique, colloidal stability of the bacteria-coated oil droplets was examined through direct-contact experiments. Both types of bacteria were seen to function as effective stabilizers. In addition, the adsorbed bacteria also interacted with one another at the interface, giving rise to higher order 2-D rheological properties. A technique of directly probing the mechanical properties of the emulsion drop surfaces revealed that (a) the films behaved as purely elastic sheets, and (b) with a reduction in cell concentration in the aqueous phase, less oil was emulsified, but the elastic moduli of the adsorbed films remained unchanged. These results are in contrast to the above millimetre-scale study. Therefore the rheological properties of these bacteria-adsorbed films appear to be length scale-dependent. An oil displacement experiment was designed to investigate the flow behaviour of micron-scale emulsion drops in a constricted channel. The qualitative results can be correlated with the interfacial rheological properties and may have valuable relevance to the study of multiphase flow through constricted channels in porous rocks (e.g. in MEOR operations).

  15. Quick and simple estimation of bacteria using a fluorescent paracetamol dimer-Au nanoparticle composite

    NASA Astrophysics Data System (ADS)

    Sahoo, Amaresh Kumar; Sharma, Shilpa; Chattopadhyay, Arun; Ghosh, Siddhartha Sankar

    2012-02-01

    Rapid, simple and sensitive detection of bacterial contamination is critical for safeguarding public health and the environment. Herein, we report an easy method of detection as well as enumeration of the bacterial cell number on the basis of fluorescence quenching of a non-antibacterial fluorescent nanocomposite, consisting of paracetamol dimer (PD) and Au nanoparticles (NPs), in the presence of bacteria. The composite was synthesized by reaction of paracetamol (p-hydroxyacetanilide) with HAuCl4. The Au NPs of the composite were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and selected area electron diffraction analysis. The paracetamol dimer in the composite showed emission peak at 435 nm when excited at 320 nm. The method successfully detected six bacterial strains with a sensitivity of 100 CFU mL-1. The Gram-positive and Gram-negative bacteria quenched the fluorescence of the composite differently, making it possible to distinguish between the two. The TEM analysis showed interaction of the composite with bacteria without any apparent damage to the bacteria. The chi-square test established the accuracy of the method. Quick, non-specific and highly sensitive detection of bacteria over a broad range of logarithmic dilutions within a short span of time demonstrates the potential of this method as an alternative to conventional methods.Rapid, simple and sensitive detection of bacterial contamination is critical for safeguarding public health and the environment. Herein, we report an easy method of detection as well as enumeration of the bacterial cell number on the basis of fluorescence quenching of a non-antibacterial fluorescent nanocomposite, consisting of paracetamol dimer (PD) and Au nanoparticles (NPs), in the presence of bacteria. The composite was synthesized by reaction of paracetamol (p-hydroxyacetanilide) with HAuCl4. The Au NPs of the composite were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and selected area electron diffraction analysis. The paracetamol dimer in the composite showed emission peak at 435 nm when excited at 320 nm. The method successfully detected six bacterial strains with a sensitivity of 100 CFU mL-1. The Gram-positive and Gram-negative bacteria quenched the fluorescence of the composite differently, making it possible to distinguish between the two. The TEM analysis showed interaction of the composite with bacteria without any apparent damage to the bacteria. The chi-square test established the accuracy of the method. Quick, non-specific and highly sensitive detection of bacteria over a broad range of logarithmic dilutions within a short span of time demonstrates the potential of this method as an alternative to conventional methods. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11837h

  16. Discovering lactic acid bacteria by genomics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on 20 different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in fermentati...

  17. Prospects & Overviews Why bacteria matter in animal

    E-print Network

    homeostasis. In a squid, microbes control the development of the symbiotic light organ. These discoveries. Epithelia in metazoans do not only select their microbiota; a coevolved consortium of microbes ena- bles system and to control pathogenic bacteria. Microbes in zebrafish and mice regulate gut epithelial

  18. Sexual isolation in bacteria Jacek Majewski *

    E-print Network

    Majewski, Jacek

    , but suffers from the negative effect of importing potentially harmful alleles from incompatible genomes. There are documented cases of exchange of genetic material between bacteria, archea, plants and yeast [1]. Inter in the environment. Conjugation is mediated by con- jugative plasmids or transposons; after formation of a pilus

  19. Probiotics Bacteria in Fermented Dairy Products

    Microsoft Academic Search

    Omer Turki Mamdoh Ershidat; Ayman Suliman Mazahreh

    2009-01-01

    The nutritional value of diary based product that contains probiotic bacteria on the gastrointestinal health and functions have been investigated in this study. Both probiotic Lactobacillus bulgaricus and Streptococcus thermophilus species, contribute to the formation of yogurt as a result of anaerobi c fermentation of lactic acid in the milk. The benefits of yogurt consumption on the gastrointestinal function mediated

  20. NARMS: ENTERIC BACTERIA - ANIMAL SALMONELLA AND CAMPYLOBACTER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objectives: Agricultural use of antimicrobials can select for antibiotic resistance both in pathogens and in commensal organisms which may transfer resistance to humans through the food supply. Antibiotic resistance is on the increase among foodborne pathogens and other bacteria. The purpose of this...

  1. INTERACTIONS OF INTRODUCED BACTERIA AND AQUATIC INVERTEBRATES

    EPA Science Inventory

    Bacteria enter into stream environments from a variety of sources and interact in varying ways with other biota. There were three basic objectives for this project: 1) to examine the effect of different types of macroinvertebrates on bacterial survival and distribution, 2) to com...

  2. Anammox bacteria: from discovery to application

    Microsoft Academic Search

    J. Gijs Kuenen

    2008-01-01

    Anaerobic ammonium oxidation (anammox) bacteria, which were discovered in waste-water sludge in the early 1990s, have the unique metabolic ability to combine ammonium and nitrite or nitrate to form nitrogen gas. This discovery led to the realization that a substantial part of the enormous nitrogen losses that are observed in the marine environment — up to 50% of the total

  3. Carbohydrate Metabolism in Bifidobacteria: Human Symbiotic Bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bifidobacterium ssp. constitute up to 90% of microbial gut flora in the infant colon, but considerably less in adults. Carbohydrate metabolism in these bacteria is highly unusual. Data from four Bifidobacterium genomes indicates genes missing from glycolysis, gluconeogenesis, and the TCA cycle, in...

  4. Magnetic properties of heterotrophic bacteria (abstract)

    NASA Astrophysics Data System (ADS)

    Verkhovceva, Nadezda V.; Glebova, Irina N.; Romanuk, Anatoly V.

    1994-05-01

    The magnetic properties (magnetic susceptibility and saturation magnetization) of six species of heterotrophic bacteria were studied: alcaligenes faecalis 81, arthrobacter globiformis BKM 685, bacillus cereus 8, leptothrix pseudo-ochracea D-405, proteus vulgaris 14, and seliberia stellata. It has been shown that the magnetic properties of bacteria depend on (1) the peculiarity of the micro-organism (species-specific and connected with cultivation conditions); (2) the source of the iron in the media. Most of the bacteria are diamagnetic in media with a minimum of iron (??=-7.2-0.3×10-6 sm3/g). The spore forming species (bacillus cereus) has increased diamagnetism. Usually the bacteria are paramagnetic in iron-containing media because they concentrate into Fe compounds. The paramagnetism of the iron-concentrating species (anthrobacter globiformis -?par=2.4×10-6, leptothrix pseudo-ochtracea ?par=11.0×10-6 and seliberia stellata ?par=3.2×10-6 sm3/g) depends, in general, on magnetically ordered compounds. Iron compounds not accumulated by proteus vulgaris and these species are always diamagnetic .

  5. Forty years of genetic recombination in bacteria

    Microsoft Academic Search

    Joshua Lederberg

    1986-01-01

    Between April and June 1946, Joshua Lederberg and Edward L. Tatum carried out a series of experiments that proved that bacteria can exchange their genes by sexual crossings. The experiments were reported in Nature just 40 years ago1. In the following pair of articles, Joshua Lederberg first provides a personal reminiscence of the circumstances of the discovery and then, together

  6. Sulfide utilization by purple nonsulfur bacteria

    Microsoft Academic Search

    Theo A. Hansen; Hans Gemerden

    1972-01-01

    The purple nonsulfur bacteria Rhodospirillum rubrum SMG 107, Rhodopseudomonas capsulata SMG 155, Rps. sphaeroides SMG 158 and Rps. palustris SMG 124 were tested for a possible utilization of sulfide. The first three strains were found to oxidize sulfide to extracellular elemental sulfur only, whereas Rps. palustris SMG 124 converted sulfide into sulfate without intermediate accumulation of elemental sulfur. Growth ceased

  7. Thermally Stable Amylases from Antarctic Psychrophilic Bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrolysis of starch in cold environments by psychrophilic species of bacteria is believed to be accomplished through the production of special cold-adapted amylases. These amylases are reportedly thermally labile with low (<40 deg C) temperature optima and high specific activities at 0 to 25 deg C....

  8. DETOXIFICATION BY MAGNETOTACTIC BACTERIA IN SEDIMENTS

    EPA Science Inventory

    The ability of certain bacteria to take up iron in the environment and biosynthesis magnetic materials such as magnetite (Fe3O4) and greigite (Fe3S4) has been recognized (Blakemore, 1982; Bazylinski and Frankel, 2000). Two different mechanisms, biologically induced mineralizat...

  9. Self-engineering capabilities of bacteria

    PubMed Central

    Ben-Jacob, Eshel; Levine, Herbert

    2005-01-01

    Under natural growth conditions, bacteria can utilize intricate communication capabilities (e.g. quorum-sensing, chemotactic signalling and plasmid exchange) to cooperatively form (self-organize) complex colonies with elevated adaptability—the colonial pattern is collectively engineered according to the encountered environmental conditions. Bacteria do not genetically store all the information required for creating all possible patterns. Instead, additional information is cooperatively generated as required for the colonial self-organization to proceed. We describe how complex colonial forms (patterns) emerge through the communication-based singular interplay between individual bacteria and the colony. Each bacterium is, by itself, a biotic autonomous system with its own internal cellular informatics capabilities (storage, processing and assessment of information). These afford the cell plasticity to select its response to biochemical messages it receives, including self-alteration and the broadcasting of messages to initiate alterations in other bacteria. Hence, new features can collectively emerge during self-organization from the intracellular level to the whole colony. The cells thus assume newly co-generated traits and abilities that are not explicitly stored in the genetic information of the individuals. PMID:16849231

  10. Transport of bacteria in unsaturated porous media

    NASA Astrophysics Data System (ADS)

    Schäfer, Anke; Ustohal, Petr; Harms, Hauke; Stauffer, Fritz; Dracos, Themistocles; Zehnder, Alexander J. B.

    1998-09-01

    Bacterial mobility in unsaturated soils plays an important role in bioremediation, biofacilitated transport of pollutants, and dispersal of pathogenic microorganisms. A sand column equipped with ports for measuring water pressure and water saturation has been used to study bacterial transport under well-defined unsaturated flow conditions. Bacterial breakthrough curves at various water saturations were obtained for two soil bacteria. Retention of hydrophobic Rhodococcus sp. C125 and mesohydrophilic Pseudomonas putida mt2 was markedly increased at lower water saturation. A mechanistic model for bacterial transport under unsaturated conditions is proposed. The model attributes stronger bacterial retention under unsaturated conditions to the accumulation of bacteria at the air-water interface. Moreover, the model takes into account changes in the available surface areas of both the solid surface and the air-water interface due to coverage by bacteria and changes in the water flow. Application of the model to our own data and data from the literature showed that short-term breakthrough experiments can be simulated, but that the model deviates from experimental observation in long-term experiments. Reasons for this deviation are discussed, and suggestions for a further model extension are made. All investigated colloidal particles had a higher affinity to the air-water interface than to the solid surface. Therefore, trapping of bacteria by air-water interfaces is an important process possibly controlling bacterial transport in unsaturated soils.

  11. Discovering lactic acid bacteria by genomics

    Microsoft Academic Search

    Todd Klaenhammer; Eric Altermann; Fabrizio Arigoni; Alexander Bolotin; Fred Breidt; Jeffrey Broadbent; Raul Cano; Stephane Chaillou; Josef Deutscher; Mike Gasson; Maarten van de Gutche; Jean Guzzo; Axel Hartke; Trevor Hawkins; Pascal Hols; Robert W. Hutkins; Michiel Kleerebezem; Jan Kok; Oscar Kuipers; Mark Lubbers; Emanuelle Maguin; Larry McKay; David Mills; Arjen Nauta; Ross Overbeek; Herman Pel; David Pridmore; Milton Saier; Douwe van Sinderen; Alexei Sorokin; James Steele; Daniel OSullivan; Willem de Vos; Bart Weimer; Monique Zagorec; Roland Seizen

    2002-01-01

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in fermentation, bioprocessing, or probiotics. For those projects where genome sequence data were available by March 2002, summaries include a listing

  12. Factors affecting the bacteria heterotrophic nanoflagellate

    E-print Network

    Jacquet, Stéphan

    Factors affecting the bacteria­ heterotrophic nanoflagellate relationship in oligo´ DU QUE´BEC A` MONTRE´AL, CP 8888, SUCC. CENTRE VILLE, MONTRE´AL, QC, H3C 3P8, 1 GRIL ­ DE´ PARTEMENT DE SCIENCES BIOLOGIQUES, UNIVERSITE´ DE MONTRE´ AL, CP 6128, SUCC. CENTRE VILLE, MONTRE´ AL, QC, H3C

  13. Anchoring of proteins to lactic acid bacteria

    Microsoft Academic Search

    Girbe Buist; Kees Leenhouts; Jan Kok

    1999-01-01

    The anchoring of proteins to the cell surface of lactic acid bacteria (LAB) using genetic techniques is an exciting and emerging research area that holds great promise for a wide variety of biotechnological applications. This paper reviews five different types of anchoring domains that have been explored for their efficiency in attaching hybrid proteins to the cell membrane or cell

  14. DISTRIBUTION OF PLASMIDS IN GROUNDWATER BACTERIA

    EPA Science Inventory

    Bacteria isolated from groundwater aquifer core materials of pristine aquifers at Lula and Pickett, Oklahoma, and from a site with a history of aromatic hydrocarbon contamination and natural renovation located at Conroe, Texas, were screened for the presence of plasmid Deoxyribon...

  15. ACETOGENIC BACTERIA ASSOCIATED WITH SEAGRASS ROOTS

    EPA Science Inventory

    Seagrasses are adapted to being rooted in reduced, anoxic sediments with high rates of sulfate reduction. During the day, an oxygen gradient is generated around the roots, becoming anoxic at night. Thus, obligate anaerobic bacteria in the rhizosphere have to tolerate elevated oxy...

  16. Freeze-drying of lactic acid bacteria.

    PubMed

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery. PMID:25428024

  17. Food phenolics and lactic acid bacteria

    Microsoft Academic Search

    Héctor Rodríguez; José Antonio Curiel; José María Landete; Blanca de las Rivas; Félix López de Felipe; Carmen Gómez-Cordovés; José Miguel Mancheño; Rosario Muñoz

    2009-01-01

    Phenolic compounds are important constituents of food products of plant origin. These compounds are directly related to sensory characteristics of foods such as flavour, astringency, and colour. In addition, the presence of phenolic compounds on the diet is beneficial to health due to their chemopreventive activities against carcinogenesis and mutagenesis, mainly due to their antioxidant activities. Lactic acid bacteria (LAB)

  18. The proteolytic system of lactic acid bacteria.

    PubMed

    Mayo, B

    1993-12-01

    Lactic acid bacteria are widely used throughout the world, empirically or deliberately, in the manufacturing of several food and feed stuffs, including milk products (such as cheese, butter, yoghurt, buttermilk, etc.), fermented vegetables (pickles, olives and sauerkraut), sausages, sourdough bread and silage, due to their ability to convert sugars into lactic acid. Of these, dairy products are of outstanding economic importance. Starter cultures used in the dairy industry are mixtures of carefully selected lactic acid bacteria which are added to the milk to fulfil the desired fermentation. Dairy starter cultures must reach high densities in milk in order to produce lactic acid at the required rates for manufacturing. Under these conditions, amino acids supply becomes limitant due to their scarce concentration in milk and to the auxotrophies shown by many starter bacteria. This implies the necessity of a proteolytic system, able to degrade the most abundant protein in milk, casein, into assimilable amino acids and peptides. Casein degradation and utilization require the concerted action of proteinases, peptidases and amino acid and peptide uptake systems. This whole set of enzymes constitutes the proteolytic system. In this article an overview of the recent biochemical and genetic data on the proteolytic system of lactic acid bacteria will be presented. PMID:8172695

  19. Joseph Jones: Infection with flesh eating bacteria

    Microsoft Academic Search

    William F. Quirk; George Sternbach

    1996-01-01

    A Confederate Army surgeon, Joseph Jones, is generally credited to have provided the first modern description of necrotizing fasciitis, then known as hospital gangrene. This is a soft tissue infection characterized by a rapid and progressive course. In the 1990s, this entity has been popularized by the media as representing infection with “flesh eating bacteria.” Certain patients are at particular

  20. Symbiosis of Thioautotrophic Bacteria with Riftia Introduction

    E-print Network

    Stewart, Frank

    1 Symbiosis of Thioautotrophic Bacteria with Riftia pachyptila Introduction The symbiosis between-rich hydrothermal vents. In the decade following the initial description of this symbiosis in 1981 (Cavanaugh et al of chemosynthetic symbioses. Specifically, for the R. pachyptila symbiosis, researchers provided new insights