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1
Singh, Adya P. "Certain Aspects of Bacterial Degradation of Pinus Radiata Wood". IAWA Journal 10, n.º 4 (1989): 405–15. http://dx.doi.org/10.1163/22941932-90001132.
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Bacterial degradation of tracheid walls of Pinus radiata wood was examined by transmission electron microscopy. The wall degradation appeared to be of two different forms, one where bacteria were present within tracheid walls forming tunnels as they moved - tunnelling type of degradation, and the other where bacteria degraded the wall from the lumen outwards - erosion type of degradation. The residual material arising from bacterial erosion of the tracheid wall spread to various extents into the lumen and contained mixed bacterial populations of varied forms. Microscopic details of these two degradation forms which involved adjoining wall areas of the same tracheid are described.
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Singh, Adya P., Yoon Soo Kim y Ramesh R. Chavan. "Relationship of wood cell wall ultrastructure to bacterial degradation of wood". IAWA Journal 40, n.º 4 (16 de noviembre de 2019): 845–70. http://dx.doi.org/10.1163/22941932-40190250.
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ABSTRACT This review presents information on the relationship of ultrastructure and composition of wood cell walls, in order to understand how wood degrading bacteria utilise cell wall components for their nutrition. A brief outline of the structure and composition of plant cell walls and the degradation patterns associated with bacterial degradation of wood cell walls precedes the description of the relationship of cell wall micro- and ultrastructure to bacterial degradation of the cell wall. The main topics covered are cell wall structure and composition, patterns of cell wall degradation by erosion and tunnelling bacteria, and the relationship of cell wall ultrastructure and composition to wood degradation by erosion and tunnelling bacteria. Finally, pertinent information from select recent studies employing molecular approaches to identify bacteria which can degrade lignin and other wood cell wall components is presented, and prospects for future investigations on wood degrading bacteria are explored.
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Leclerc, Denis y Alain Asselin. "Detection of bacterial cell wall hydrolases after denaturing polyacrylamide gel electrophoresis". Canadian Journal of Microbiology 35, n.º 8 (1 de agosto de 1989): 749–53. http://dx.doi.org/10.1139/m89-125.
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Cell walls from various Gram-positive bacteria were incorporated at a concentration of 0.2% (w/v) into polyacrylamide gels as a substrate for detection of cell wall hydrolases. Bacterial extracts from crude cell wall preparations were denatured with sodium dodecyl sulfate and 2-mercaptoethanol and subjected to denaturing polyacrylamide gel electrophoresis in gels containing bacterial cell walls. After renaturation in the presence of purified and buffered 1% (v/v) Triton X-100, cell wall hydrolases were visualized as clear lytic zones against the opaque cell wall background. One to fifteen bands with lytic activity could be detected, depending on bacterial extracts and on the nature of the cell walls incorporated into gels. Crude cell wall extracts were the best source of cell wall hydrolases from various Gram-positive bacteria such as Clostridium perfringens (15 bands), Micrococcus luteus (1 band), Bacillus megaterium (4 bands), Bacillus sp. (6 bands), B. cereus (3 bands), B. subtilis (7 bands), Staphylococcus aureus (13 bands), Streptococcus faecalis (3 bands), and Strep. pyogenes (5 bands). Molecular masses of cell wall hydrolases ranged from 17 to 114.6 kDa. Lytic activities against cell walls of Corynebacterium sepedonicum (Clavibacter michiganense pv. sepedonicum) could be shown with the cell wall extracts of Strep. pyogenes (45.7 kDa), Strep. faecalis (67 kDa), B. megaterium (67 kDa), and Staph. aureus (67 kDa).Key words: autolysins, electrophoresis, hydrolases, muramidases, peptidoglycan.
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Tokárová, Viola, Ayyappasamy Sudalaiyadum Perumal, Monalisha Nayak, Henry Shum, Ondřej Kašpar, Kavya Rajendran, Mahmood Mohammadi et al. "Patterns of bacterial motility in microfluidics-confining environments". Proceedings of the National Academy of Sciences 118, n.º 17 (19 de abril de 2021): e2013925118. http://dx.doi.org/10.1073/pnas.2013925118.
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Understanding the motility behavior of bacteria in confining microenvironments, in which they search for available physical space and move in response to stimuli, is important for environmental, food industry, and biomedical applications. We studied the motility of five bacterial species with various sizes and flagellar architectures (Vibrio natriegens, Magnetococcus marinus, Pseudomonas putida, Vibrio fischeri, and Escherichia coli) in microfluidic environments presenting various levels of confinement and geometrical complexity, in the absence of external flow and concentration gradients. When the confinement is moderate, such as in quasi-open spaces with only one limiting wall, and in wide channels, the motility behavior of bacteria with complex flagellar architectures approximately follows the hydrodynamics-based predictions developed for simple monotrichous bacteria. Specifically, V. natriegens and V. fischeri moved parallel to the wall and P. putida and E. coli presented a stable movement parallel to the wall but with incidental wall escape events, while M. marinus exhibited frequent flipping between wall accumulator and wall escaper regimes. Conversely, in tighter confining environments, the motility is governed by the steric interactions between bacteria and the surrounding walls. In mesoscale regions, where the impacts of hydrodynamics and steric interactions overlap, these mechanisms can either push bacteria in the same directions in linear channels, leading to smooth bacterial movement, or they could be oppositional (e.g., in mesoscale-sized meandered channels), leading to chaotic movement and subsequent bacterial trapping. The study provides a methodological template for the design of microfluidic devices for single-cell genomic screening, bacterial entrapment for diagnostics, or biocomputation.
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Singh, Adya P., Shruti Singh y Ehsan Bari. "Bacterial Degradation of Wood by Tunnel Formation: Role of TEM in Understanding the Intricate Architecture of Tunnels and the Cell Wall Degradation Process". Microscopy Today 30, n.º 5 (septiembre de 2022): 24–30. http://dx.doi.org/10.1017/s1551929522001080.
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Abstract:Certain bacteria degrade wood by creating tunnels in cell walls. Transmission electron microscopy (TEM) has played a key role in understanding the intricate architecture of the tunnels produced within the cell wall and the process of cell wall degradation. The most prominent feature of tunnels is the presence of periodic crescent-shaped slime bands, which is the single most important diagnostic characteristic of bacterial tunneling-type cell wall degradation. The review presented covers the aspects relevant to understanding bacterial tunneling of wood cell walls, emphasizing the importance of the application of TEM in this area of research.
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Kennedy, John F. y Jiro Shimizu. "Bacterial cell wall". Carbohydrate Polymers 29, n.º 3 (marzo de 1996): 294. http://dx.doi.org/10.1016/0144-8617(96)82557-4.
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Tsuneda, A. y R. G. Thorn. "Interactions of wood decay fungi with other microorganisms, with emphasis on the degradation of cell walls". Canadian Journal of Botany 73, S1 (31 de diciembre de 1995): 1325–33. http://dx.doi.org/10.1139/b95-394.
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Interactions of two wood decay fungi, Lentinula edodes and Pleurotus ostreatus, with other wood inhabiting microorganisms were investigated on agar and in fagaceous wood, primarily by scanning electron microscopy. Micromorphologically, there were two principal modes of cell wall degradation: (i) selective removal of amorphous wall components, followed by the degradation of skeletal microfibrils, and (ii) simultaneous degradation of all wall components. These two modes were observed in three different degradation systems: (i) sapwood wall degradation by the wood decay fungi, (ii) hyphal wall degradation by mycoparasitic Trichoderma, and (iii) hyphal wall degradation by pathogenic bacteria. The simultaneous-type wall degradation in the systems i and ii was usually caused by hyphal tips. In addition to the three systems, bacteriolysis by the wood decay fungi was also studied. The bacterial cell walls, as well as microfibril bundles of wood cellulose and fungal chitin, were all fragmented into minute granules at later stages of microbial degradation and the granules were further degraded into smaller units. Frequency of occurrence and strength of mycoparasitic activity of Trichoderma harzianum were influenced by the degree of wood decay where the interaction occurred. Presence of both cellulose and chitin microfibrils apparently enhanced the mycoparasitic activity. In Quercus wood, P. ostreatus showed a unidirectional growth toward bacterial colonies, which formed as the result of decomposition of dead nematodes, and consumed the unidentified bacteria. In nitrogen-deficient wood, fungal and bacterial cell walls may serve as an important reservoir of nitrogen for wood inhabiting microorganisms. Key words: wood decay, mycoparasitism, bacteriolysis, cellulose, chitin.
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Shan, Li, Qin Wenling, Panunzio Mauro y Biondi Stefano. "Antibacterial Agents Targeting the Bacterial Cell Wall". Current Medicinal Chemistry 27, n.º 17 (4 de junio de 2020): 2902–26. http://dx.doi.org/10.2174/0929867327666200128103653.
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The introduction of antibiotics to treat bacterial infections either by killing or blocking their growth has been accompanied by the studies of mechanism that allows the drugs to kill the bacteria or to stop their proliferation. In such a scenario, the emergence of antibacterial agents active on the bacterial cell wall has been of fundamental importance in the fight against bacterial agents responsible for severe diseases. As a matter of fact, the cell wall, which plays many roles during the lifecycle, is an essential constituent of most bacteria. This overview focuses on the intracellular steps of peptidoglycan biosynthesis and the research of new antibacterial agents based on the enzymes involved in these early steps of the formation of cell membrane components.
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Do, Truc, Julia E. Page y Suzanne Walker. "Uncovering the activities, biological roles, and regulation of bacterial cell wall hydrolases and tailoring enzymes". Journal of Biological Chemistry 295, n.º 10 (23 de enero de 2020): 3347–61. http://dx.doi.org/10.1074/jbc.rev119.010155.
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Bacteria account for 1000-fold more biomass than humans. They vary widely in shape and size. The morphological diversity of bacteria is due largely to the different peptidoglycan-based cell wall structures that encase bacterial cells. Although the basic structure of peptidoglycan is highly conserved, consisting of long glycan strands that are cross-linked by short peptide chains, the mature cell wall is chemically diverse. Peptidoglycan hydrolases and cell wall–tailoring enzymes that regulate glycan strand length, the degree of cross-linking, and the addition of other modifications to peptidoglycan are central in determining the final architecture of the bacterial cell wall. Historically, it has been difficult to biochemically characterize these enzymes that act on peptidoglycan because suitable peptidoglycan substrates were inaccessible. In this review, we discuss fundamental aspects of bacterial cell wall synthesis, describe the regulation and diverse biochemical and functional activities of peptidoglycan hydrolases, and highlight recently developed methods to make and label defined peptidoglycan substrates. We also review how access to these substrates has now enabled biochemical studies that deepen our understanding of how bacterial cell wall enzymes cooperate to build a mature cell wall. Such improved understanding is critical to the development of new antibiotics that disrupt cell wall biogenesis, a process essential to the survival of bacteria.
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Šimelyte, Egle, Marja Rimpiläinen, Leena Lehtonen, Xiang Zhang y Paavo Toivanen. "Bacterial Cell Wall-Induced Arthritis: Chemical Composition and Tissue Distribution of Four Lactobacillus Strains". Infection and Immunity 68, n.º 6 (1 de junio de 2000): 3535–40. http://dx.doi.org/10.1128/iai.68.6.3535-3540.2000.
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ABSTRACT To study what determines the arthritogenicity of bacterial cell walls, cell wall-induced arthritis in the rat was applied, using four strains of Lactobacillus. Three of the strains used proved to induce chronic arthritis in the rat; all were Lactobacillus casei. The cell wall of Lactobacillus fermentum did not induce chronic arthritis. All arthritogenic bacterial cell walls had the same peptidoglycan structure, whereas that of L. fermentum was different. Likewise, all arthritogenic cell walls were resistant to lysozyme degradation, whereas the L. fermentum cell wall was lysozyme sensitive. Muramic acid was observed in the liver, spleen, and lymph nodes in considerably larger amounts after injection of an arthritogenicL. casei cell wall than following injection of a nonarthritogenic L. fermentum cell wall. The L. casei cell wall also persisted in the tissues longer than theL. fermentum cell wall. The present results, taken together with those published previously, underline the possibility that the chemical structure of peptidoglycan is important in determining the arthritogenicity of the bacterial cell wall.
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Bower, Sam y Ken S. Rosenthal. "The Bacterial Cell Wall". Infectious Diseases in Clinical Practice 14, n.º 5 (septiembre de 2006): 309–17. http://dx.doi.org/10.1097/01.idc.0000240862.74564.57.
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BORMAN, STU. "BACTERIAL WALL COMPONENT MADE". Chemical & Engineering News 85, n.º 32 (6 de agosto de 2007): 6. http://dx.doi.org/10.1021/cen-v085n032.p006.
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Johnson, Jarrod W., Jed F. Fisher y Shahriar Mobashery. "Bacterial cell-wall recycling". Annals of the New York Academy of Sciences 1277, n.º 1 (16 de noviembre de 2012): 54–75. http://dx.doi.org/10.1111/j.1749-6632.2012.06813.x.
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Meyer, P. "The Bacterial Cell Wall". Research in Microbiology 153, n.º 10 (diciembre de 2002): 693. http://dx.doi.org/10.1016/s0923-2508(02)01384-0.
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Radkov, Atanas D., Yen-Pang Hsu, Garrett Booher y Michael S. VanNieuwenhze. "Imaging Bacterial Cell Wall Biosynthesis". Annual Review of Biochemistry 87, n.º 1 (20 de junio de 2018): 991–1014. http://dx.doi.org/10.1146/annurev-biochem-062917-012921.
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Peptidoglycan is an essential component of the cell wall that protects bacteria from environmental stress. A carefully coordinated biosynthesis of peptidoglycan during cell elongation and division is required for cell viability. This biosynthesis involves sophisticated enzyme machineries that dynamically synthesize, remodel, and degrade peptidoglycan. However, when and where bacteria build peptidoglycan, and how this is coordinated with cell growth, have been long-standing questions in the field. The improvement of microscopy techniques has provided powerful approaches to study peptidoglycan biosynthesis with high spatiotemporal resolution. Recent development of molecular probes further accelerated the growth of the field, which has advanced our knowledge of peptidoglycan biosynthesis dynamics and mechanisms. Here, we review the technologies for imaging the bacterial cell wall and its biosynthesis activity. We focus on the applications of fluorescent d-amino acids, a newly developed type of probe, to visualize and study peptidoglycan synthesis and dynamics, and we provide direction for prospective research.
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Masaaki Minami, Shunsuke Akahori, Hiroshi Takase y Michio Ohta. "Effects of LytR on bacterial morphology in Streptococcus pyognes". GSC Biological and Pharmaceutical Sciences 22, n.º 2 (28 de febrero de 2023): 014–19. http://dx.doi.org/10.30574/gscbps.2023.22.2.0046.
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A robust cell envelope is the first line of defense in infectious pathogens when encountering host immune defenses. In Gram-positive bacteria, LytR-CpsA-Psr (LCP) family proteins play a major role in the synthesis and assembly of the cell envelope. The Gram-positive bacterium S. pyogenes causes a wide range of diseases from pharyngitis to septicemia, but the involvement of LytR in the synthesis and assembly of the cell wall envelope in this bacterium is not clear. Therefore, we investigated whether LytR of S. pyogenes, like LytR of other streptococci, is involved in cell wall formation. The lytR gene-deficient strains were used to investigate the bacteria's ability to form a chaining, drug sensitivity to penicillin G, an inhibitor of cell wall synthesis, bacterial biofilm formation, and the morphological structure of bacteria by transmission electron microscopy, and the expression of pbp2b, which encodes a penicillin-binding protein, compared with the wild-type strain. Our results showed that LytR-deficient strains had reduced bacterial chaining compared to wild-type strains. Compared to wild-type strains, LytR-deficient strains were also more drug sensitive to the cell wall synthesis inhibitor penicillin G. This genetic study was accompanied by increased expression of the pbp2b gene in the LytR-deficient strains. In addition, the LytR-deficient strain showed a reduced ability to form biofilms, and the lytR gene-deficient strain showed morphological irregularities with abnormal bacterial septa. These results indicate that the lytR gene is involved in cell wall synthesis in S. pyognes.
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Roy, Priti Kumar, Yanhui Zhang, Priyanka Ghosh, Joydeep Pal y Fahad Al Basir. "Role of antibiotic therapy in bacterial disease: A mathematical study". International Journal of Biomathematics 11, n.º 03 (abril de 2018): 1850038. http://dx.doi.org/10.1142/s1793524518500389.
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Pathogenic bacteria in human system mature through the bio-synthesis of protective layer known as cell wall. This bacterial cell wall growth occurs in the presence of enzyme released by it. After maturation by the cell wall formation, pathogenic bacteria become harmful for human body as they are responsible for different diseases. Antibiotics or drugs are employed for curing bacterial diseases through the inhibition of this maturation process and it occurs by the binding progression of antibiotics with the released enzyme. But nowadays, drugs or antibiotics like [Formula: see text]-lactum family (Amoxcillin) which are generally used for inhibition of bio-synthesis of cell wall become ineffective due to evolution of antibiotic resistance by the bacteria. Antibiotic resistance occurs when an antibiotic has lost its ability to effectively control or kill bacterial growth. As a result, the bacteria becomes “resistant” and continue to multiply for the generation of robust pathogenic bacteria in spite of drug administration. This is due to the release of another type of enzyme by the resistant bacteria which binds with the active antibiotic or drug making it ineffective. Hence, another type of drug (Clauvanic acid) is combined to resist the activity of drug hydrolyzing enzyme so that the initial drug can act effectively. Hence a combination of drug therapy is applied to cure the bacterial diseases successfully. We developed a mathematical model based on the bacterial enzyme and bacterial cell wall proliferation mechanism and showed how we can reduce the bacterial infection in the resistant cases with application of combination drugs (Amoxcillin and Clauvanic acid) to restore normal health. Based on the enzymatic activity and individual drug dynamics we studied the overall system under the single drug and combinational drug administration through our formulated model analysis. We also demonstrated the different dosing time interval and dosing concentration to evaluate the optimized drug administration for arresting the cell wall formation completely. Sensitivity of the different kinetic rate constant also has been performed with subject to drug hydrolyzing enzyme. Our analytical and numerical studies also confirm the efficiency of the combinational drug treatment compared to single drug treatment being more effective in drug resistant cases providing recovery from bacterial disease.
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Li, Jia, Xiaomin Hu, Jianpin Yan y Zhiming Yuan. "Species-Specific Cell Wall Binding Affinity of the S-Layer Proteins of Mosquitocidal Bacterium Bacillus sphaericus C3-41". Applied and Environmental Microbiology 75, n.º 12 (24 de abril de 2009): 3891–95. http://dx.doi.org/10.1128/aem.00356-09.
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ABSTRACT The binding affinities and specificities of six truncated S-layer homology domain (SLH) polypeptides of mosquitocidal Bacillus sphaericus strain C3-41 with the purified cell wall sacculi have been assayed. The results indicated that the SLH polypeptide comprised of amino acids 31 to 210 was responsible for anchoring the S-layer subunits to the rigid cell wall layer via a distinct type of secondary cell wall polymer and that a motif of the recombinant SLH polypeptide comprising amino acids 152 to 210 (rSLH152-210) was essential for the stable binding of the S-layer with the bacterial cell walls. The quantitative assays revealed that the KD (equilibrium dissociation constant) values of rSLH152-210 and rSLH31-210 with purified cell wall sacculi were 1.11 × 10−6 M and 1.40 × 10−6 M, respectively. The qualitative assays demonstrated that the SLH domain of strain C3-41 could bind only to the cell walls or the cells treated with 5 M guanidinium hydrochloride of both toxic and nontoxic B. sphaericus strains but not to those from other bacteria, indicating the species-specific binding of the SLH polypeptide of B. sphaericus with bacterial cell walls.
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Parvin, Farhana, Md Arifur Rahman, Anand K. Deva, Karen Vickery y Honghua Hu. "Staphylococcus aureus Cell Wall Phenotypic Changes Associated with Biofilm Maturation and Water Availability: A Key Contributing Factor for Chlorine Resistance". International Journal of Molecular Sciences 24, n.º 5 (5 de marzo de 2023): 4983. http://dx.doi.org/10.3390/ijms24054983.
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Staphylococcus aureus biofilms are resistant to both antibiotics and disinfectants. As Staphylococci cell walls are an important defence mechanism, we sought to examine changes to the bacterial cell wall under different growth conditions. Cell walls of S. aureus grown as 3-day hydrated biofilm, 12-day hydrated biofilm, and 12-day dry surface biofilm (DSB) were compared to cell walls of planktonic organisms. Additionally, proteomic analysis using high-throughput tandem mass tag-based mass spectrometry was performed. Proteins involved in cell wall synthesis in biofilms were upregulated in comparison to planktonic growth. Bacterial cell wall width (measured by transmission electron microscopy) and peptidoglycan production (detected using a silkworm larva plasma system) increased with biofilm culture duration (p < 0.001) and dehydration (p = 0.002). Similarly, disinfectant tolerance was greatest in DSB, followed by 12-day hydrated biofilm and then 3-day biofilm, and it was least in the planktonic bacteria––suggesting that changes to the cell wall may be a key factor for S. aureus biofilm biocide resistance. Our findings shed light on possible new targets to combat biofilm-related infections and hospital dry surface biofilms.
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Raz, Assaf, Anna Serrano, Christine Lawson, Maneesha Thaker, Tricia Alston, Stylianos Bournazos, Jeffrey V. Ravetch y Vincent A. Fischetti. "Lysibodies are IgG Fc fusions with lysin binding domains targetingStaphylococcus aureuswall carbohydrates for effective phagocytosis". Proceedings of the National Academy of Sciences 114, n.º 18 (20 de abril de 2017): 4781–86. http://dx.doi.org/10.1073/pnas.1619249114.
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The cell wall of Gram-positive bacteria contains abundant surface-exposed carbohydrate molecules that are highly conserved within and often across species. The potential therapeutic usefulness of high-affinity antibodies to cell wall carbohydrates is unquestioned, however obtaining such antibodies is challenging due to the poor overall immunogenicity of these bacterial targets. Autolysins and phage lysins are peptidoglycan hydrolases, enzymes that have evolved over a billion years to degrade bacterial cell wall. Such wall hydrolases are modular enzymes, composed of discrete domains for high-affinity binding to cell wall carbohydrates and cleavage activity. In this study, we demonstrate that binding domains from autolysins and lysins can be fused to the Fc region of human IgG, creating a fully functional homodimer (or “lysibody”) with high-affinity binding and specificity for carbohydrate determinants on the bacterial surface. Furthermore, we demonstrate that this process is reproducible with three different binding domains specific to methicillin-resistantStaphylococcus aureus(MRSA). Cell-bound lysibodies induced the fixation of complement on the bacterial surface, promoted phagocytosis by macrophages and neutrophils, and protected mice from MRSA infection in two model systems. The lysibody approach could be used to target a range of difficult-to-treat pathogenic bacteria, given that cell wall hydrolases are ubiquitous in nature.
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Kochan, Kamila, David Perez-Guaita, Julia Pissang, Jhih-Hang Jiang, Anton Y. Peleg, Don McNaughton, Philip Heraud y Bayden R. Wood. "In vivo atomic force microscopy–infrared spectroscopy of bacteria". Journal of The Royal Society Interface 15, n.º 140 (marzo de 2018): 20180115. http://dx.doi.org/10.1098/rsif.2018.0115.
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A new experimental platform for probing nanoscale molecular changes in living bacteria using atomic force microscopy–infrared (AFM–IR) spectroscopy is demonstrated. This near-field technique is eminently suited to the study of single bacterial cells. Here, we report its application to monitor dynamical changes occurring in the cell wall during cell division in Staphylococcus aureus using AFM to demonstrate the division of the cell and AFM–IR to record spectra showing the thickening of the septum . This work was followed by an investigation into single cells, with particular emphasis on cell-wall signatures, in several bacterial species. Specifically, mainly cell wall components from S. aureus and Escherichia coli containing complex carbohydrate and phosphodiester groups, including peptidoglycans and teichoic acid, could be identified and mapped at nanometre spatial resolution. Principal component analysis of AFM–IR spectra of six living bacterial species enabled the discrimination of Gram-positive from Gram-negative bacteria based on spectral bands originating mainly from the cell wall components. The ability to monitor in vivo molecular changes during cellular processes in bacteria at the nanoscale opens a new platform to study environmental influences and other factors that affect bacterial chemistry.
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Snyder, Aleksandra y Hélène Marquis. "Restricted Translocation across the Cell Wall Regulates Secretion of the Broad-Range Phospholipase C of Listeria monocytogenes". Journal of Bacteriology 185, n.º 20 (15 de octubre de 2003): 5953–58. http://dx.doi.org/10.1128/jb.185.20.5953-5958.2003.
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ABSTRACT The virulence of Listeria monocytogenes is directly related to its ability to spread from cell to cell without leaving the intracellular milieu. During cell-to-cell spread, bacteria become temporarily confined to secondary vacuoles. Among the bacterial factors involved in escape from these vacuoles is a secreted broad-range phospholipase C (PC-PLC), the activation of which requires processing of an N-terminal prodomain. Mpl, a secreted metalloprotease of Listeria, is involved in the proteolytic activation of PC-PLC. We previously showed that, during intracellular growth, bacteria maintain a pool of PC-PLC that is not accessible to antibodies and that is rapidly released in its active form in response to a decrease in pH. pH-regulated release of active PC-PLC is Mpl dependent. To further characterize the mechanism regulating secretion of PC-PLC, the bacterial localization of PC-PLC and Mpl was investigated. Both proteins were detected in the bacterial supernatant and lysate with no apparent changes in molecular weight. Extraction of bacteria-associated PC-PLC and Mpl required cell wall hydrolysis, but there was no indication that either protein was covalently bound to the bacterial cell wall. Results from pulse-chase experiments performed with infected macrophages indicated that the rate of synthesis of PC-PLC exceeded the rate of translocation across the bacterial cell wall and confirmed that the pool of PC-PLC associated with bacteria was efficiently activated and secreted upon acidification of the host cell cytosol. These data suggest that bacterially associated PC-PLC and Mpl localize at the cell wall-membrane interface and that translocation of PC-PLC across the bacterial cell wall is rate limiting, resulting in the formation of a bacterially associated pool of PC-PLC that would readily be accessible for activation and release into nascent secondary vacuoles.
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Potomkin, M., M. Tournus, L. V. Berlyand y I. S. Aranson. "Flagella bending affects macroscopic properties of bacterial suspensions". Journal of The Royal Society Interface 14, n.º 130 (mayo de 2017): 20161031. http://dx.doi.org/10.1098/rsif.2016.1031.
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To survive in harsh conditions, motile bacteria swim in complex environments and respond to the surrounding flow. Here, we develop a mathematical model describing how flagella bending affects macroscopic properties of bacterial suspensions. First, we show how the flagella bending contributes to the decrease in the effective viscosity observed in dilute suspension. Our results do not impose tumbling (random reorientation) as was previously done to explain the viscosity reduction. Second, we demonstrate how a bacterium escapes from wall entrapment due to the self-induced buckling of flagella. Our results shed light on the role of flexible bacterial flagella in interactions of bacteria with shear flow and walls or obstacles.
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Tan, Michelle S. F., Sadequr Rahman y Gary A. Dykes. "Pectin and Xyloglucan Influence the Attachment of Salmonella enterica and Listeria monocytogenes to Bacterial Cellulose-Derived Plant Cell Wall Models". Applied and Environmental Microbiology 82, n.º 2 (13 de noviembre de 2015): 680–88. http://dx.doi.org/10.1128/aem.02609-15.
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ABSTRACTMinimally processed fresh produce has been implicated as a major source of foodborne microbial pathogens globally. These pathogens must attach to the produce in order to be transmitted. Cut surfaces of produce that expose cell walls are particularly vulnerable. Little is known about the roles that different structural components (cellulose, pectin, and xyloglucan) of plant cell walls play in the attachment of foodborne bacterial pathogens. Using bacterial cellulose-derived plant cell wall models, we showed that the presence of pectin alone or xyloglucan alone affected the attachment of threeSalmonella entericastrains (Salmonella entericasubsp.entericaserovar Enteritidis ATCC 13076,Salmonella entericasubsp.entericaserovar Typhimurium ATCC 14028, andSalmonella entericasubsp.indicaM4) andListeria monocytogenesATCC 7644. In addition, we showed that this effect was modulated in the presence of both polysaccharides. Assays using pairwise combinations ofS.Typhimurium ATCC 14028 andL. monocytogenesATCC 7644 showed that bacterial attachment to all plant cell wall models was dependent on the characteristics of the individual bacterial strains and was not directly proportional to the initial concentration of the bacterial inoculum. This work showed that bacterial attachment was not determined directly by the plant cell wall model or bacterial physicochemical properties. We suggest that attachment of theSalmonellastrains may be influenced by the effects of these polysaccharides on physical and structural properties of the plant cell wall model. Our findings improve the understanding of howSalmonella entericaandListeria monocytogenesattach to plant cell walls, which may facilitate the development of better ways to prevent the attachment of these pathogens to such surfaces.
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Mitchell, Gabriel J., Kurt Wiesenfeld, Daniel C. Nelson y Joshua S. Weitz. "Critical cell wall hole size for lysis in Gram-positive bacteria". Journal of The Royal Society Interface 10, n.º 80 (6 de marzo de 2013): 20120892. http://dx.doi.org/10.1098/rsif.2012.0892.
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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.
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Dobbins, William O. "Bacterial cell wall-induced enterocolitis". Gastroenterology 90, n.º 1 (enero de 1986): 256–57. http://dx.doi.org/10.1016/0016-5085(86)90121-6.
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Sartor, R. Balfour. "Bacterial cell wall-induced enterocolitis". Gastroenterology 90, n.º 1 (enero de 1986): 257. http://dx.doi.org/10.1016/0016-5085(86)90122-8.
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Errington, Jeff. "L-form bacteria, cell walls and the origins of life". Open Biology 3, n.º 1 (enero de 2013): 120143. http://dx.doi.org/10.1098/rsob.120143.
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The peptidoglycan wall is a defining feature of bacterial cells and was probably already present in their last common ancestor. L-forms are bacterial variants that lack a cell wall and divide by a variety of processes involving membrane blebbing, tubulation, vesiculation and fission. Their unusual mode of proliferation provides a model for primitive cells and is reminiscent of recently developed in vitro vesicle reproduction processes. Invention of the cell wall may have underpinned the explosion of bacterial life on the Earth. Later innovations in cell envelope structure, particularly the emergence of the outer membrane of Gram-negative bacteria, possibly in an early endospore former, seem to have spurned further major evolutionary radiations. Comparative studies of bacterial cell envelope structure may help to resolve the early key steps in evolutionary development of the bacterial domain of life.
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Korobov, V. P., B. Ts Shagdarova, V. P. Varlamov, A. L. Esaev y T. V. Polyudova. "Inhibitory Action of Low-Molecular Chitosan on Growth of Bacteria with Different Tinctorial Properties". Микробиология 92, n.º 2 (1 de marzo de 2023): 197–203. http://dx.doi.org/10.31857/s0026365622600754.
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Abstract—Inhibitory effect of chitosan (molecular mass 28 kDa, deacetylation 94%) and of its quaternized derivative with 60% substitution on bacteria of various taxonomic groups was investigated. Bacteria differing in the cell wall surface characteristics and affinity to dyes were found to differ in theri sensitivity to chitosan. Correlation dependencies between antibacterial activity of quaternized chitosan and the surface characteristics of bacterial cell walls were revealed.
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Asadi, Sepideh y Neda Soleimani. "Anticancer Effect of Fractions From Staphylococcus aureus and Bacillus atrophaeus on the Proliferation and Death of Human Breast Cancer Cell Line (MCF-7)". International Journal of Enteric Pathogens 8, n.º 4 (30 de diciembre de 2020): 116–21. http://dx.doi.org/10.34172/ijep.2020.25.
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Background: Nowadays, breast cancer is known to be one of the most common cancers among women. Due to the side effects of chemotherapy and the high probability of recurrences in surgery, it is essential to identify and introduce new anticancer drugs of natural origin with fewer complications. In this regard, secondary bacterial metabolites and other microbial products have been considered. In the meantime, pathogenic and environmental bacteria have been investigated. Objective: The aim of this study is to examine the effects of the interaction between cytoplasmic extract and the cell wall of Staphylococcus aureus and Bacillus atrophaeus on the proliferation rate of human breast cancer cells. Materials and Methods: In this experimental study, cytoplasmic and cell wall extracts of bacteria were prepared. Then, SDS-PAGE was used to examine their protein contents. MCF-7 cells, as human breast cancer cells, with bacterial cytoplasmic extract and bacterial cell wall, were treated at different concentrations. Mesenchymal stem cells derived from adipose tissue were treated with different concentrations of bacterial cell wall extract. The effects of cytotoxicity were assessed by MTT assay at 24 and 48-hour intervals. The results were analyzed by SPSS. Results: The results showed that bacterial cytoplasmic extract had a concentration-dependent cytotoxic effect on cancer cells, suggesting that the increase of concentration significantly (P<0.05) increased cell death. Additionally, the bacterial cell wall extract showed a proliferative effect on cell growth (P<0.05) Conclusion: The bacterial cytoplasmic extract has a lethal effect and can, therefore, be considered as an anticancer compound in the future. This feature of the bacterium is attributed to the presence of a novel bioactive compound that can be used as an adjunct to other chemotherapy compounds. The bacterial cell wall extract, on the other hand, has cell growth-promoting components and can, therefore, be adopted as a compound for the proliferation of mesenchymal stem cells or wound healing in future studies.
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van Tol, Eric A. F., Lisa Holt, Feng Ling Li, Feng-Ming Kong, Richard Rippe, Mitsuo Yamauchi, Jolanta Pucilowska, P. Kay Lund y R. Balfour Sartor. "Bacterial cell wall polymers promote intestinal fibrosis by direct stimulation of myofibroblasts". American Journal of Physiology-Gastrointestinal and Liver Physiology 277, n.º 1 (1 de julio de 1999): G245—G255. http://dx.doi.org/10.1152/ajpgi.1999.277.1.g245.
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Normal luminal bacteria and bacterial cell wall polymers are implicated in the pathogenesis of chronic intestinal inflammation. To determine the direct involvement of bacteria and their products on intestinal fibrogenesis, the effects of purified bacterial cell wall polymers on collagen and cytokine synthesis were evaluated in intestinal myofibroblast cultures established from normal fetal and chronically inflamed cecal tissues. In this study, the intestines of Lewis rats were intramurally injected with peptidoglycan-polysaccharide polymers. Collagen and transforming growth factor (TGF)-β1 mRNA levels were measured and correlated with mesenchymal cell accumulation by immunohistochemistry. The direct effects of cell wall polymers on fibrogenic cytokine and collagen α1 (type I) expression were evaluated in intestinal myofibroblast cultures. We found that intramural injections of bacterial cell wall polymers induced chronic granulomatous enterocolitis with markedly increased collagen synthesis and concomitant increased TGF-β1 and interleukin (IL)-6 expression. Intestinal myofibroblast cultures were established, which both phenotypically and functionally resemble the mesenchymal cells that are involved in fibrosis in vivo. Bacterial cell wall polymers directly stimulated collagen α1 (I), TGF-β1, IL-1β, and IL-6 mRNA expression in the intestinal myofibroblasts derived from both normal and inflamed cecum. Neutralization of endogenous TGF-β1 inhibited in vitro collagen gene expression. From our results, we conclude that increased exposure to luminal bacterial products can directly activate intestinal mesenchymal cells, which accumulate in areas of chronic intestinal inflammation, thus stimulating intestinal fibrosis in genetically susceptible hosts.
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Radford, Sheena. "Building the Bacterial Cell Wall: How Do Bacteria Do It?" Biophysical Journal 120, n.º 3 (febrero de 2021): 107a. http://dx.doi.org/10.1016/j.bpj.2020.11.867.
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Lee, S. S., J. K. Ha y K. J. Cheng. "Relative Contributions of Bacteria, Protozoa, and Fungi to In Vitro Degradation of Orchard Grass Cell Walls and Their Interactions". Applied and Environmental Microbiology 66, n.º 9 (1 de septiembre de 2000): 3807–13. http://dx.doi.org/10.1128/aem.66.9.3807-3813.2000.
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ABSTRACT To assess the relative contributions of microbial groups (bacteria, protozoa, and fungi) in rumen fluids to the overall process of plant cell wall digestion in the rumen, representatives of these groups were selected by physical and chemical treatments of whole rumen fluid and used to construct an artificial rumen ecosystem. Physical treatments involved homogenization, centrifugation, filtration, and heat sterilization. Chemical treatments involved the addition of antibiotics and various chemicals to rumen fluid. To evaluate the potential activity and relative contribution to degradation of cell walls by specific microbial groups, the following fractions were prepared: a positive system (whole ruminal fluid), a bacterial (B) system, a protozoal (P) system, a fungal (F) system, and a negative system (cell-free rumen fluid). To assess the interactions between specific microbial fractions, mixed cultures (B+P, B+F, and P+F systems) were also assigned. Patterns of degradation due to the various treatments resulted in three distinct groups of data based on the degradation rate of cell wall material and on cell wall-degrading enzyme activities. The order of degradation was as follows: positive and F systems > B system > negative and P systems. Therefore, fungal activity was responsible for most of the cell wall degradation. Cell wall degradation by the anaerobic bacterial fraction was significantly less than by the fungal fraction, and the protozoal fraction failed to grow under the conditions used. In general, in the mixed culture systems the coculture systems demonstrated a decrease in cellulolysis compared with that of the monoculture systems. When one microbial fraction was associated with another microbial fraction, two types of results were obtained. The protozoal fraction inhibited cellulolysis of cell wall material by both the bacterial and the fungal fractions, while in the coculture between the bacterial fraction and the fungal fraction a synergistic interaction was detected.
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Dik, David A., Nan Zhang, Emily J. Sturgell, Brittany B. Sanchez, Jason S. Chen, Bill Webb, Kimberly G. Vanderpool y Peter G. Schultz. "A synthetic 5,3-cross-link in the cell wall of rod-shaped Gram-positive bacteria". Proceedings of the National Academy of Sciences 118, n.º 11 (8 de marzo de 2021): e2100137118. http://dx.doi.org/10.1073/pnas.2100137118.
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Gram-positive bacteria assemble a multilayered cell wall that provides tensile strength to the cell. The cell wall is composed of glycan strands cross-linked by nonribosomally synthesized peptide stems. Herein, we modify the peptide stems of the Gram-positive bacterium Bacillus subtilis with noncanonical electrophilic d-amino acids, which when in proximity to adjacent stem peptides form novel covalent 5,3-cross-links. Approximately 20% of canonical cell-wall cross-links can be replaced with synthetic cross-links. While a low level of synthetic cross-link formation does not affect B. subtilis growth and phenotype, at higher levels cell growth is perturbed and bacteria elongate. A comparison of the accumulation of synthetic cross-links over time in Gram-negative and Gram-positive bacteria highlights key differences between them. The ability to perturb cell-wall architecture with synthetic building blocks provides a novel approach to studying the adaptability, elasticity, and porosity of bacterial cell walls.
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Tóth, Márta. "How genetically modified probiotic bacteria can modify human dendritic cell functions?" Journal of Immunology 196, n.º 1_Supplement (1 de mayo de 2016): 65.26. http://dx.doi.org/10.4049/jimmunol.196.supp.65.26.
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Abstract Selected lactic-acid bacterial strains such as Lactobacilli are classified as probiotics with beneficial effects on the human host. It has previously been shown that the group of Lactobacillus rhamnosus/casei/paracasei are able to prevent cytokine-induced apoptosis of intestinal epithelial cells by secreted factors identified as peptidoglycan-hydrolases. To exert their protective and immunomodulatory effects, these bacteria have to interact with the underlying epithelial and immune cells, such as dendritic cells (DCs). DCs recognize Lactobacilli and their components by pattern recognition receptors (PRR) that may induce stimulatory or inhibitory T-lymphocyte responses. Our results showed that the inflammatory response of human monocyte-derived DCs (moDCs) to bacterial stimuli and the ability to polarize T-lymphocytes to different directions was highly dependent on the intact structure of the bacterial cell wall, while the expression of the cell surface molecules of moDCs was independent on the modification of the peptidoglycan (PG) layer. It was also found that the secreted bacterial cell wall preparations were able to activate moDCs demonstrated by the increased levels of pro – and anti-inflammatory cytokines and elevated expression of cell surface markers independently on the genetic manipulation of the cell wall. Based on these results we conclude that the genetic modification of the bacterial cell wall is able to modulate the stimulatory potential of moDCs and has an impact on the outcome of T-lymphocyte responses at the level of the whole bacteria. In contrast to the effects of the specific PG extracts, the functions of moDCs are independent on the genetically modified bacteria or their cell wall and its components.
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Schäffer, Christina y Paul Messner. "The structure of secondary cell wall polymers: how Gram-positive bacteria stick their cell walls together". Microbiology 151, n.º 3 (1 de marzo de 2005): 643–51. http://dx.doi.org/10.1099/mic.0.27749-0.
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The cell wall of Gram-positive bacteria has been a subject of detailed chemical study over the past five decades. Outside the cytoplasmic membrane of these organisms the fundamental polymer is peptidoglycan (PG), which is responsible for the maintenance of cell shape and osmotic stability. In addition, typical essential cell wall polymers such as teichoic or teichuronic acids are linked to some of the peptidoglycan chains. In this review these compounds are considered as ‘classical’ cell wall polymers. In the course of recent investigations of bacterial cell surface layers (S-layers) a different class of ‘non-classical’ secondary cell wall polymers (SCWPs) has been identified, which is involved in anchoring of S-layers to the bacterial cell surface. Comparative analyses have shown considerable differences in chemical composition, overall structure and charge behaviour of these SCWPs. This review discusses the progress that has been made in understanding the structural principles of SCWPs, which may have useful applications in S-layer-based ‘supramolecular construction kits' in nanobiotechnology.
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Urdaneta, A. Barrios, M. Fondevila, J. Balcells, C. Dapoza y C. Castrillo. "In vitro microbial digestion of straw cell wall polysaccharides in response to supplementation with different sources of carbohydrates". Australian Journal of Agricultural Research 51, n.º 3 (2000): 393. http://dx.doi.org/10.1071/ar99079.
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The effect of carbohydrate supplementation on microbial fibre digestion was studied in vitro, by measuring the disappearance of cell wall monosaccharides, bacterial adhesion (mmol purine bases per g residue), and total (per g residue) and bacterial (per mmol purine bases) polysaccharidase activity. Straw cell walls (CW, 0.5% w/v) were cultured in medium supplemented with (0.275% w/v) or without starch, a sugar mixture, or pectin. Supplementation with these constituents did not cause a drop in pH below 6.1, and increased all parameters investigated with the exception of bacterial polysaccharidase activity, which was higher for CW cultures, suggesting a higher proportion of fibrolytic bacteria in the adherent population. By comparison with starch and sugar, pectin supplementation resulted in a lower proportion of residual sugars remaining from cell walls after 60 and 72 h (P < 0.05), which resulted in greater bacterial adhesion after 8 and 12 h (P < 0.05) and higher total cellulase activity after 8 h (P < 0.01). This was perhaps because pectin may cover particle surfaces, protecting the digestive area from external factors, or may act as a substrate for cellulolytic bacteria. The lack of differences in bacterial enzymatic activities suggests the absence of qualitative or quantitative differences in the adherent fibrolytic population.
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Marraffini, Luciano A., Andrea C. DeDent y Olaf Schneewind. "Sortases and the Art of Anchoring Proteins to the Envelopes of Gram-Positive Bacteria". Microbiology and Molecular Biology Reviews 70, n.º 1 (marzo de 2006): 192–221. http://dx.doi.org/10.1128/mmbr.70.1.192-221.2006.
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SUMMARY The cell wall envelopes of gram-positive bacteria represent a surface organelle that not only functions as a cytoskeletal element but also promotes interactions between bacteria and their environment. Cell wall peptidoglycan is covalently and noncovalently decorated with teichoic acids, polysaccharides, and proteins. The sum of these molecular decorations provides bacterial envelopes with species- and strain-specific properties that are ultimately responsible for bacterial virulence, interactions with host immune systems, and the development of disease symptoms or successful outcomes of infections. Surface proteins typically carry two topogenic sequences, i.e., N-terminal signal peptides and C-terminal sorting signals. Sortases catalyze a transpeptidation reaction by first cleaving a surface protein substrate at the cell wall sorting signal. The resulting acyl enzyme intermediates between sortases and their substrates are then resolved by the nucleophilic attack of amino groups, typically provided by the cell wall cross bridges of peptidoglycan precursors. The surface protein linked to peptidoglycan is then incorporated into the envelope and displayed on the microbial surface. This review focuses on the mechanisms of surface protein anchoring to the cell wall envelope by sortases and the role that these enzymes play in bacterial physiology and pathogenesis.
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Léonard, Raphaël R., Eric Sauvage, Valérian Lupo, Amandine Perrin, Damien Sirjacobs, Paulette Charlier, Frédéric Kerff y Denis Baurain. "Was the Last Bacterial Common Ancestor a Monoderm after All?" Genes 13, n.º 2 (18 de febrero de 2022): 376. http://dx.doi.org/10.3390/genes13020376.
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The very nature of the last bacterial common ancestor (LBCA), in particular the characteristics of its cell wall, is a critical issue to understand the evolution of life on earth. Although knowledge of the relationships between bacterial phyla has made progress with the advent of phylogenomics, many questions remain, including on the appearance or disappearance of the outer membrane of diderm bacteria (also called Gram-negative bacteria). The phylogenetic transition between monoderm (Gram-positive bacteria) and diderm bacteria, and the associated peptidoglycan expansion or reduction, requires clarification. Herein, using a phylogenomic tree of cultivated and characterized bacteria as an evolutionary framework and a literature review of their cell-wall characteristics, we used Bayesian ancestral state reconstruction to infer the cell-wall architecture of the LBCA. With the same phylogenomic tree, we further revisited the evolution of the division and cell-wall synthesis (dcw) gene cluster using homology- and model-based methods. Finally, extensive similarity searches were carried out to determine the phylogenetic distribution of the genes involved with the biosynthesis of the outer membrane in diderm bacteria. Quite unexpectedly, our analyses suggest that all cultivated and characterized bacteria might have evolved from a common ancestor with a monoderm cell-wall architecture. If true, this would indicate that the appearance of the outer membrane was not a unique event and that selective forces have led to the repeated adoption of such an architecture. Due to the lack of phenotypic information, our methodology cannot be applied to all extant bacteria. Consequently, our conclusion might change once enough information is made available to allow the use of an even more diverse organism selection.
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Boher, B., M. Nicole, M. Potin y J. P. Geiger. "Extracellular Polysaccharides from Xanthomonas axonopodis pv. manihotis Interact with Cassava Cell Walls During Pathogenesis". Molecular Plant-Microbe Interactions® 10, n.º 7 (septiembre de 1997): 803–11. http://dx.doi.org/10.1094/mpmi.1997.10.7.803.
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The location of lipopolysaccharides produced by Xanthomonas axonopodis pv. manihotis during pathogenesis on cassava (Manihot esculenta) was determined by fluorescence and electron microscopy immunolabeling with monoclonal antibodies. During the early stages of infection, pathogen lipopolysaccharides were detected on the outer surface of the bacterial envelope and in areas of the plant middle lamellae in the vicinity of the pathogen. Later in the infection process, lipopolysaccharide-specific antibodies bound to areas where the plant cell wall was heavily degraded. Lipopolysaccharides were not detected in the fibrillar matrix filling intercellular spaces of infected cassava leaves. Monoclonal antibodies specific for the exopolysaccharide xanthan side chain labeled the bacteria, the fibrillar matrix, and portions of the host cell wall. The association of Xanthomonas lipopolysaccharides with host cell walls during plant infection is consistent with a role of these bacterial extracellular polysaccharides in the infection process.
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Beveridge, T. J. y W. S. Fyfe. "Metal fixation by bacterial cell walls". Canadian Journal of Earth Sciences 22, n.º 12 (1 de diciembre de 1985): 1893–98. http://dx.doi.org/10.1139/e85-204.
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All biomass contains a significant quantity of metallic constituents, and mineralization in living and dead biodebris may contribute to element transport from the hydrosphere into sediments. The anionic cell walls of bacteria are remarkable in their ability to fix metals and provide sites for nucleation and growth of minerals. Results presented show the types of cell wall polymers that are responsible for metal binding in walls of Gram-positive and Gram-negative bacteria.
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Bui, Cuong, Thi Thanh Van Tran, Thi Hong Cao, Van Trang Nguyen, Trung Huy Nguyen, Quoc Thai Vu, Quoc Dung Trinh, Thi Kieu Anh Vo, Thi Xuyen Nguyen y Dai Lam Tran. "Isolation and identification of microorganisms causing water-based paint and wall paint destruction". Vietnam Journal of Science and Technology 60, n.º 6 (30 de diciembre de 2022): 1005–13. http://dx.doi.org/10.15625/2525-2518/16672.
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From samples of moldy wall paint and damaged water-based paint, we isolated and quantified the density of microorganisms present in the samples and determined the morphology of the isolates; thereby, identifying the genera of the bacteria and mold strains. The results showed that the density of the strains collected from the wall paint samples was much higher than that of the water-based paint samples (106 CFU/mL and 104 CFU/mL, respectively). In the wall paint samples, only mold colonies were observed, not bacterial colonies, while in the water-based paint samples both mold and bacterial colonies appeared, although mold colonies were still predominant. Based on the observation of colony formation and microscopic morphology of molds, we classified six mold strains into five genera: Aspergillus sp., Cladosporum sp., Acremoium sp., Chaetomium sp., and Fusarium sp. The frequency of strains belonging to the genus Aspergillus sp. accounted for the majority in both wall and water-based paint samples. Among the three bacterial strains isolated, we identified two bacterial strains as G (-) and one strain as G (+).
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Nakayama, Ken, Tadashi Furuyama, Yutaka Matsubara, Koichi Morisaki, Toshihiro Onohara, Tetsuo Ikeda y Tomoharu Yoshizumi. "Gut dysbiosis and bacterial translocation in the aneurysmal wall and blood in patients with abdominal aortic aneurysm". PLOS ONE 17, n.º 12 (14 de diciembre de 2022): e0278995. http://dx.doi.org/10.1371/journal.pone.0278995.
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Inflammation plays a part in the development of abdominal aortic aneurysm (AAA), and the gut microbiota affects host inflammation by bacterial translocation. The relationship between abdominal aortic aneurysm and the gut microbiota remains unknown. This study aimed to detect bacterial translocation in the aneurysmal wall and blood of patients with abdominal aortic aneurysm, and to investigate the effect of the gut microbiota on abdominal aortic aneurysm. We investigated 30 patients with abdominal aortic aneurysm from 2017 to 2019. We analysed the aneurysmal wall and blood using highly sensitive reverse transcription-quantitative polymerase chain reaction, and the gut microbiota was investigated using next-generation sequencing. In the 30 patients, bacteria were detected by reverse transcription- quantitative polymerase chain reaction in 19 blood samples (detection rate, 63%) and in 11 aneurysmal wall samples (detection rate, 37%). In the gut microbiota analysis, the Firmicutes/Bacteroidetes ratio was increased. The neutrophil-lymphocyte ratio was higher (2.94 ± 1.77 vs 1.96 ± 0.61, P < 0.05) and the lymphocyte-monocyte ratio was lower (4.02 ± 1.25 vs 5.86 ± 1.38, P < 0.01) in the bacterial carrier group than in the bacterial non-carrier group in blood samples. The volume of intraluminal thrombus was significantly higher in the bacterial carrier group than in the bacterial non-carrier group in aneurysmal wall samples (64.0% vs 34.7%, P < 0.05). We confirmed gut dysbiosis and bacterial translocation to the blood and aneurysmal wall in patients with abdominal aortic aneurysm. There appears to be a relationship between the gut microbiota and abdominal aortic aneurysm.
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Van Amersfoort, Edwin S., Theo J. C. Van Berkel y Johan Kuiper. "Receptors, Mediators, and Mechanisms Involved in Bacterial Sepsis and Septic Shock". Clinical Microbiology Reviews 16, n.º 3 (julio de 2003): 379–414. http://dx.doi.org/10.1128/cmr.16.3.379-414.2003.
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SUMMARY Bacterial sepsis and septic shock result from the overproduction of inflammatory mediators as a consequence of the interaction of the immune system with bacteria and bacterial wall constituents in the body. Bacterial cell wall constituents such as lipopolysaccharide, peptidoglycans, and lipoteichoic acid are particularly responsible for the deleterious effects of bacteria. These constituents interact in the body with a large number of proteins and receptors, and this interaction determines the eventual inflammatory effect of the compounds. Within the circulation bacterial constituents interact with proteins such as plasma lipoproteins and lipopolysaccharide binding protein. The interaction of the bacterial constituents with receptors on the surface of mononuclear cells is mainly responsible for the induction of proinflammatory mediators by the bacterial constituents. The role of individual receptors such as the toll-like receptors and CD14 in the induction of proinflammatory cytokines and adhesion molecules is discussed in detail. In addition, the roles of a number of other receptors that bind bacterial compounds such as scavenger receptors and their modulating role in inflammation are described. Finally, the therapies for the treatment of bacterial sepsis and septic shock are discussed in relation to the action of the aforementioned receptors and proteins.
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Chen, Yun, Akshay K. Harapanahalli, Henk J. Busscher, Willem Norde y Henny C. van der Mei. "Nanoscale Cell Wall Deformation Impacts Long-Range Bacterial Adhesion Forces on Surfaces". Applied and Environmental Microbiology 80, n.º 2 (8 de noviembre de 2013): 637–43. http://dx.doi.org/10.1128/aem.02745-13.
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ABSTRACTAdhesion of bacteria occurs on virtually all natural and synthetic surfaces and is crucial for their survival. Once they are adhering, bacteria start growing and form a biofilm, in which they are protected against environmental attacks. Bacterial adhesion to surfaces is mediated by a combination of different short- and long-range forces. Here we present a new atomic force microscopy (AFM)-based method to derive long-range bacterial adhesion forces from the dependence of bacterial adhesion forces on the loading force, as applied during the use of AFM. The long-range adhesion forces of wild-typeStaphylococcus aureusparent strains (0.5 and 0.8 nN) amounted to only one-third of these forces measured for their more deformable isogenic Δpbp4mutants that were deficient in peptidoglycan cross-linking. The measured long-range Lifshitz-Van der Waals adhesion forces matched those calculated from published Hamaker constants, provided that a 40% ellipsoidal deformation of the bacterial cell wall was assumed for the Δpbp4mutants. Direct imaging of adhering staphylococci using the AFM peak force-quantitative nanomechanical property mapping imaging mode confirmed a height reduction due to deformation in the Δpbp4mutants of 100 to 200 nm. Across naturally occurring bacterial strains, long-range forces do not vary to the extent observed here for the Δpbp4mutants. Importantly, however, extrapolating from the results of this study, it can be concluded that long-range bacterial adhesion forces are determined not only by the composition and structure of the bacterial cell surface but also by a hitherto neglected, small deformation of the bacterial cell wall, facilitating an increase in contact area and, therewith, in adhesion force.
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Yoshimura, Atsutoshi, Egil Lien, Robin R. Ingalls, Elaine Tuomanen, Roman Dziarski y Douglas Golenbock. "Cutting Edge: Recognition of Gram-Positive Bacterial Cell Wall Components by the Innate Immune System Occurs Via Toll-Like Receptor 2". Journal of Immunology 163, n.º 1 (1 de julio de 1999): 1–5. http://dx.doi.org/10.4049/jimmunol.163.1.1.
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Abstract Invasive infection with Gram-positive and Gram-negative bacteria often results in septic shock and death. The basis for the earliest steps in innate immune response to Gram-positive bacterial infection is poorly understood. The LPS component of the Gram-negative bacterial cell wall appears to activate cells via CD14 and Toll-like receptor (TLR) 2 and TLR4. We hypothesized that Gram-positive bacteria might also be recognized by TLRs. Heterologous expression of human TLR2, but not TLR4, in fibroblasts conferred responsiveness to Staphylococcus aureus and Streptococcus pneumoniae as evidenced by inducible translocation of NF-κB. CD14 coexpression synergistically enhanced TLR2-mediated activation. To determine which components of Gram-positive cell walls activate Toll proteins, we tested a soluble preparation of peptidoglycan prepared from S. aureus. Soluble peptidoglycan substituted for whole organisms. These data suggest that the similarity of clinical response to invasive infection by Gram-positive and Gram-negative bacteria is due to bacterial recognition via similar TLRs.
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Zhang, Xue Bin y Yoshiyuki Ohta. "Binding of mutagenic pyrolyzates to fractions of intestinal bacterial cells". Canadian Journal of Microbiology 38, n.º 7 (1 de julio de 1992): 614–17. http://dx.doi.org/10.1139/m92-101.
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The binding of mutagenic pyrolyzates to cell fractions from some gram-negative intestinal bacteria and to thermally treated bacterial cells was investigated. 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) were effectively bound by several of the bacterial cells. The cell wall skeletons of all bacteria effectively bound Trp-P-1 and Trp-P-2. Their cytoplasmic fractions retained Trp-P-1 and Trp-P-2, but to a lesser extent than the cell wall skeletons. 2-Amino-3-methylimidazo [4,5-f]quinoline (IQ) was not found in their cytoplasmic fractions. These cell wall skeletons also bound 2-amino-6-methyldipyrido[1,2-a:3′2′-d] imidazole (Glu-P-1), 2-amino-5-phenylpyridine (Phe-P-1), IQ, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQX). The amount of each mutagen bound differed with the type of mutagen and the bacterial strain used. The outer membrane of Escherichia coli IFO 14249 showed binding of about 123.7 μg/mg of Trp-P-2, and its cytoplasmic membrane bound 57.14 μg/mg. Trp-P-2 bound to the bacterial cells was extracted with ammonia (5%), methanol, and ethanol but not with water. Key words: cell wall skeletons, outer membrane, cytoplasmic membrane, binding of mutagenic pyrolyzates.
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Yan, Ningzhe, Hao Luo, Yanan Liu, Haiping Yu y Guangyin Jing. "Motility Suppression and Trapping Bacteria by ZnO Nanostructures". Crystals 12, n.º 8 (23 de julio de 2022): 1027. http://dx.doi.org/10.3390/cryst12081027.
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Regulating the swimming motility of bacteria near surfaces is essential to suppress or avoid bacterial contamination and infection in catheters and medical devices with wall surfaces. However, the motility of bacteria near walls strongly depends on the combination of the local physicochemical properties of the surfaces. To unravel how nanostructures and their local chemical microenvironment dynamically affect the bacterial motility near surfaces, here, we directly visualize the bacterial swimming and systematically analyze the motility of Escherichia coli swimming on ZnO nanoparticle films and nanowire arrays with further ultraviolet irradiation. The results show that the ZnO nanowire arrays reduce the swimming motility, thus significantly enhancing the trapping ability for motile bacteria. Additionally, thanks to the wide bandgap nature of a ZnO semiconductor, the ultraviolet irradiation rapidly reduces the bacteria locomotion due to the hydroxyl and singlet oxygen produced by the photodynamic effects of ZnO nanowire arrays in an aqueous solution. The findings quantitatively reveal how the combination of geometrical nanostructured surfaces and local tuning of the steric microenvironment are able to regulate the motility of swimming bacteria and suggest the efficient inhibition of bacterial translocation and infection by nanostructured coatings.
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Umeda, Akiko y Kazunobu Amako. "Structure of the Bacterial Cell Wall." Nippon Ishinkin Gakkai Zasshi 39, n.º 3 (1998): 147–50. http://dx.doi.org/10.3314/jjmm.39.147.
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Koch, Arthur L. "Bacterial Wall as Target for Attack". Clinical Microbiology Reviews 16, n.º 4 (octubre de 2003): 673–87. http://dx.doi.org/10.1128/cmr.16.4.673-687.2003.
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SUMMARY When Bacteria, Archaea, and Eucarya separated from each other, a great deal of evolution had taken place. Only then did extensive diversity arise. The bacteria split off with the new property that they had a sacculus that protected them from their own turgor pressure. The saccular wall of murein (or peptidoglycan) was an effective solution to the osmotic pressure problem, but it then was a target for other life-forms, which created lysoymes and β-lactams. The β-lactams, with their four-member strained rings, are effective agents in nature and became the first antibiotic in human medicine. But that is by no means the end of the story. Over evolutionary time, bacteria challenged by β-lactams evolved countermeasures such as β-lactamases, and the producing organisms evolved variant β-lactams. The biology of both classes became evident as the pharmaceutical industry isolated, modified, and produced new chemotherapeutic agents and as the properties of β-lactams and β-lactamases were examined by molecular techniques. This review attempts to fit the wall biology of current microbes and their clinical context into the way organisms developed on this planet as well as the changes arising since the work done by Fleming. It also outlines the scientific advances in our understanding of this broad area of biology.