Showing papers on "Bacteria published in 1988"
TL;DR: The range of inhibitory activity by bacteriocins of lactic acid bacteria can be either narrow, inhibiting only those strains that are closely related to the producer organism, or wide, inhibited a diverse group of Gram-positive microorganisms as mentioned in this paper.
1,754 citations
TL;DR: In this article, the authors developed a protocol which yields purified bacterial DNA from the soil bacterial community, which was essentially pure as determined by UV spectral analysis, was at least 48 kilobases long, and was not subject to degradation, which indicated that there was no contaminating nuclease activity.
Abstract: We developed a protocol which yields purified bacterial DNA from the soil bacterial community. The bacteria were first dispersed and separated from soil particles in the presence of polyvinylpolypyrrolidone, which removes humic acid contaminants by adsorption to this insoluble polymer. The soil bacteria were then collected by centrifugation and lysed by using a comprehensive protocol designed to maximize disruption of the various types of bacteria present. Total bacterial DNA was purified from the cell lysate and remaining soil contaminants by using equilibrium density gradients. The isolated DNA was essentially pure as determined by UV spectral analysis, was at least 48 kilobases long, and was not subject to degradation, which indicated that there was no contaminating nuclease activity. The isolated DNA was readily digested by exogenously added restriction endonucleases and successfully analyzed by slot blot and Southern blot hybridizations. Using single-stranded, P-labeled DNA probes, we could detect and quantitate the presence of a specific microbial population in the natural soil community on the basis of the presence of a DNA sequence unique to that organism. The sensitivity of our methodology was sufficient to detect Bradyrhizobium japonicum at densities as low as 4.3 x 10 cells per g (dry weight) of soil, which corresponds to about 0.2 pg of hybridizable DNA in a 1-mug DNA sample.
599 citations
TL;DR: Experiments showed that monochloramine was as effective as free chlorine for inactivation of biofilm bacteria and the interaction of biocides with pipe surfaces provides important insights into strategies for control ofBiofilm bacteria.
Abstract: The current project was developed to examine inactivation of biofilm bacteria and to characterize the interaction of biocides with pipe surfaces. Unattached bacteria were quite susceptible to the variety of disinfectants tested. Viable bacterial counts were reduced 99% by exposure to 0.08 mg of hypochlorous acid (pH 7.0) per liter (1 to 2 degrees C) for 1 min. For monochloramine, 94 mg/liter was required to kill 99% of the bacteria within 1 min. These results were consistent with those found by other investigators. Biofilm bacteria grown on the surfaces of granular activated carbon particles, metal coupons, or glass microscope slides were 150 to more than 3,000 times more resistant to hypochlorous acid (free chlorine, pH 7.0) than were unattached cells. In contrast, resistance of biofilm bacteria to monochloramine disinfection ranged from 2- to 100-fold more than that of unattached cells. The results suggested that, relative to inactivation of unattached bacteria, monochloramine was better able to penetrate and kill biofilm bacteria than free chlorine. For free chlorine, the data indicated that transport of the disinfectant into the biofilm was a major rate-limiting factor. Because of this phenomenon, increasing the level of free chlorine did not increase disinfection efficiency. Experiments where equal weights of disinfectants were used suggested that the greater penetrating power of monochloramine compensated for its limited disinfection activity. These studies showed that monochloramine was as effective as free chlorine for inactivation of biofilm bacteria. The research provides important insights into strategies for control of biofilm bacteria.
583 citations
TL;DR: To examine the possible role of carbohydrates as adhesion receptors for infection, several pulmonary pathogenic bacteria were studied for binding to glycosphingolipids to suggest that at least terminal or internal GalNAc beta 1-4Gal sequences unsubstituted with sialyl residues for binding are required.
Abstract: Pneumonia is one of the most common causes of death from infectious disease in the United States. To examine the possible role of carbohydrates as adhesion receptors for infection, several pulmonary pathogenic bacteria were studied for binding to glycosphingolipids. Radiolabeled bacteria were layered on thin-layer chromatograms of separated glycosphingolipids, and bound bacteria were detected by autoradiography. The classic triad of infectious bacteria found in cystic fibrosis, Pseudomonas aeruginosa, Haemophilus influenzae, and Staphylococcus aureus, along with other bacteria commonly implicated in typical pneumonia, such as Streptococcus pneumoniae, Klebsiella pneumoniae, and certain Escherichia coli, bind specifically to fucosylasialo-GM1 (Fuc alpha 1-2Gal beta 1-3GalNAc beta 1-4Gal beta 1-4Cer), asialo-GM1 (Gal beta 1-3GalNAc beta 1-4Gal beta-1-4Galc beta 1-1Cer), and asialo-GM2 (GalNAc beta 1-4Gal beta 1-4Glc beta 1-1Cer). Bacteria maintained in nutrient medium bind better than the same cells suspended in buffer. They do not bind to galactosylceramide, glucosylceramide, lactosylceramide, trihexosylceramide, globoside, paragloboside, Forssman glycosphingolipid, or several other glycosphingolipids tested, including the gangliosides GM1, GM2, GM3, GD1a, GD1b, GT1b, and Cad. The finding that these pathogens do not bind to lactosylceramide suggests that beta 1-4-linked GalNAc, which is positioned internally in fucosylasialo-GM1 and asialo-GM1 and terminally in asialo-GM2, is required for binding. beta-N-Acetylgalactosamine itself, however, is not sufficient for binding, as the bacteria did not bind to globoside, which contains the terminal sequence GalNAc beta 1-3Gal. These data suggest that these bacteria require at least terminal or internal GalNAc beta 1-4Gal sequences unsubstituted with sialyl residues for binding. Other bacteria, including Mycoplasma pneumoniae, Streptococcus pyogenes, Salmonella species, and some E. coli, do not bind to the GalNAc beta 1-4Gal sequence. The biological relevance of these data is suggested by our finding that substantial amounts of asialo-GM1 occur in human lung tissue.
405 citations
TL;DR: It is proposed that resistance to digestion by predatory protozoa was an evolutionary precursor of pathogenicity in bacteria and that today it is a mechanism for survival of fastidious bacteria in dilute and inhospitable aquatic environments.
Abstract: The susceptibility of coliform bacteria and bacterial pathogens to free chlorine residuals was determined before and after incubation with amoebae and ciliate protozoa. Viability of bacteria was quantified to determine their resistance to free chlorine residuals when ingested by laboratory strains of Acanthamoeba castellanii and Tetrahymena pyriformis. Cocultures of bacteria and protozoa were incubated to facilitate ingestion of the bacteria and then were chlorinated, neutralized, and sonicated to release intracellular bacteria. Qualitative susceptibility of protozoan strains to free chlorine was also assessed. Protozoa were shown to survive and grow after exposure to levels of free chlorine residuals that killed free-living bacteria. Ingested coliforms Escherichia coli, Citrobacter freundii, Enterobacter agglomerans, Enterobacter cloacae, Klebsiella pneumoniae, and Klebsiella oxytoca and bacterial pathogens Salmonella typhimurium, Yersinia enterocolitica, Shigella sonnei, Legionella gormanii, and Campylobacter jejuni had increased resistance to free chlorine residuals. Bacteria could be cultured from within treated protozoans well after the time required for 99% inactivation of free-living cells. All bacterial pathogens were greater than 50-fold more resistant to free chlorine when ingested by T. pyriformis. Escherichia coli ingested by a Cyclidium sp., a ciliate isolated from a drinking water reservoir, were also shown to be more resistant to free chlorine. The mechanism that increased resistance appeared to be survival within protozoan cells. This study indicates that bacteria can survive ingestion by protozoa. This bacterium-protozoan association provides bacteria with increased resistance to free chlorine residuals which can lead to persistence of bacteria in chlorine-treated water. We propose that resistance to digestion by predatory protozoa was an evolutionary precursor of pathogenicity in bacteria and that today it is a mechanism for survival of fastidious bacteria in dilute and inhospitable aquatic environments.
369 citations
Journal Article•
TL;DR: In this article, it was shown that the growth of B. coli and a number of other bacteria belonging to the colityphoid group was not inhibited by penicillin.
Abstract: FLEMING1 noted that the growth of B. coli and a number of other bacteria belonging to the colityphoid group was not inhibited by penicillin. This observation has been confirmed. Further work has been done to find the cause of the resistance of these organisms to the action of penicillin.
355 citations
TL;DR: Data provide further evidence that sulfated polysaccharides such as mucin may be a source of sulfate for SRB in the human large gut.
Abstract: A mixed culture of human fecal bacteria was grown for 120 days in a three-stage continuous culture system. To reproduce some of the nutritional and pH characteristics of the large gut, each vessel had a different operating volume (0.3, 0.5, and 0.8 liter) and pH (6.0, 6.5, and 7.0). A mixture of polysaccharides and proteins was used as carbon and nitrogen sources. Measurements of H2, CH4, S2-, sulfate reduction rates, sulfate-reducing bacteria (SRB), and volatile fatty acids were made throughout the experiment. After 48 days of running, porcine gastric mucin (5.8 g/day) was independently fed to vessel 1 of the multichamber system. The mucin was extensively degraded as evidenced by the stimulation of volatile fatty acid production. In the absence of mucin, sulfate-reducing activity was comparatively insignificant and methanogenesis was the major route for the disposal of electrons. The reverse occurred upon the addition of mucin; sulfate reduction predominated and methanogenesis was completely inhibited. This was attributed to release of sulfate from the mucin which enabled SRB to outcompete methanogenic bacteria for H2. SRB stimulated by mucin were acetate-utilizing Desulfobacter spp., lactate- and H2-utilizing Desulfovibrio spp., and propionate-utilizing Desulfobulbus spp. When the mucin pump was switched off, the multichamber system reverted to a state close to its original equilibrium. These data provide further evidence that sulfated polysaccharides such as mucin may be a source of sulfate for SRB in the human large gut.
259 citations
TL;DR: Enteric bacilli such as Escherichia coli, Proteus, and Enterobacter are associated with a higher incidence of bacteremia in debilitated patients, because these bacteria translocate more efficiently from the GI tract than do other bacteria, especially obligate anaerobes.
Abstract: Bacterial translocation is defined as the passage of indigenous bacteria from the gastrointestinal (GI) tract through the lamina propria to the mesenteric lymph nodes (MLN) and other organs. We compared the relative abilities of various aerobic, facultatively anaerobic, and obligately anaerobic bacteria to translocate from the GI tract to the MLN in gnotobiotic mice colonized with single strains of bacteria. Indigenous gram-negative enteric bacilli translocated in large numbers to the MLN, whereas gram-positive bacteria translocated at intermediate levels and obligately anaerobic bacteria at only very low levels. Our results suggest that enteric bacilli such as Escherichia coli, Proteus, and Enterobacter are associated with a higher incidence of bacteremia in debilitated patients, because these bacteria translocate more efficiently from the GI tract than do other bacteria, especially obligate anaerobes.
241 citations
TL;DR: Thermophilic, reddish-coloured heterotrophic bacteria different from Thermus were isolated from submarine alkaline hot springs in Iceland, considered to represent a new genus which is named Rhodothermus, with the type species Rhodother Mus marinus.
Abstract: SUMMARY: Thermophilic, reddish-coloured heterotrophic bacteria different from Thermus were isolated from submarine alkaline hot springs in Iceland. The bacteria were obligately aerobic, moderately halophilic, Gram-negative rods, about 0.5 μm in diameter and 2-2.5 μm long. Neither spores, flagella nor lipid granules were observed, but a slime capsule was formed on carbohydrate-rich medium. Optimum growth was at 65°C, pH 7.0, and at about 2% (w/v) NaCl. The bacteria were oxidase negative, catalase positive and contained a carotenoid pigment with the main absorbance peak at 476 nm and shoulders at 456 and 502 nm. The GC content of the DNA was about 64 mol%. Electron micrographs clearly showed an outer membrane, about 9 nm thick, and the cytoplasmic membrane together with the peptidoglycan layer was about 14 nm in thickness. The isolates were nutritionally different from Thermus. They utilized several common sugars but glutamate and aspartate were the only amino acids that most strains used. These bacteria are considered to represent a new genus which we name Rhodothermus, with the type species Rhodothermus marinus.
192 citations
TL;DR: Experiments conducted using cell-free supernatant fluids of marine bacteria demonstrated the involvement of antibiotic substances in the inhibition of fish pathogens.
Abstract: The activity of antibiotic-producing marine bacteria was assayed against bacterial fish pathogens belonging to the genera Vibrio, Aeromonas, Pasteurella, Edwardsiella, Yersinia and Pseudomonas with the aim of evaluating the possible use of these marine strains for controlling epizootics in aquaculture. Inhibition tests on solid medium showed that, in general, the majority of fish bacteria were strongly sensitive to the marine bacteria. Only two strains (Edwardsiella tarda and Pseudomonas aeruginosa), were resistant to all the antibiotic-producing strains. The results of antagonism assays in sea water, however, varied according to the fish pathogens examined. Experiments conducted using cell-free supernatant fluids of marine bacteria demonstrated the involvement of antibiotic substances in the inhibition of fish pathogens.
192 citations
TL;DR: Significant evidence has accumulated for the importance of non-porin pathways of antibiotic uptake across the outer membranes of gram-negative bacteria, and examples discussed include the uptake of polycationic antibiotics via the self-promoted pathway, the uptake in some bacterial species and in mutants of others via the hydrophobic pathway, and the possible importance of poorly understoodnon-porIn pathways of uptake of a variety of antibiotics.
Abstract: Antibiotics taken up into gram-negative bacteria face two major diffusion barriers, the outer and cytoplasmic membranes. Of these, the former has been most studied and is discussed in detail here. Evidence from antibiotic MIC studies on porin-deficient mutants compared with their porin-sufficient parent strains has provided strong support for the proposal that some antibiotics, particularly β-lactams, pass across the outer membrane through the water-filled channels of a class of proteins called porins. Nevertheless substantial evidence has accumulated for the importance of non-porin pathways of antibiotic uptake across the outer membranes of gram-negative bacteria. Examples discussed include the uptake of polycationic antibiotics via the self-promoted pathway, the uptake of hydrophobic antibiotics in some bacterial species and in mutants of others via the hydrophobic pathway, and the possible importance of poorly understood non-porin pathways of uptake of a variety of antibiotics. Other potential barriers to diffusion, including the cytoplasmic membrane, are briefly discussed.
Book•
01 Jan 1988
TL;DR: This work has presented methods for the study of Bacterial Attachment, isolation, interactions and ecology of Methanogenic Bacteria in Aquatic Environments, and Assessment of Bacteria Activity Nitrate Metabolism by Aquatic Bacteria.
Abstract: Sampling Methods Determination of Biomass Isolation Methods Identification Bacteria of Fish Bacteria of Aquatic Invertebrates Epiphytic Bacteria Deep Sea Bacteria Anoxygenic Phototrophic Bacteria Cyanobacteria: Isolation, Interactions and Ecology Sulphate-Reducing Bacteria Methods to Study Methanogenic Bacteria and Methanogenic Activities in Aquatic Environments Assessment of Bacterial Activity Nitrate Metabolism by Aquatic Bacteria Methods for the Study of Bacterial Attachment.
TL;DR: On the bases of cell morphology, substrate utilization spectrum, and DNA base composition, strain JSN-2 is proposed as the type strain of the new species Sporomusa termitida.
Abstract: H2-oxidizing CO2-reducing acetogenic bacteria were isolated from gut contents of Nasutitermes nigriceps termites. Isolates were strictly anaerobic, Gram negative, endospore-forming, straight to slightly curved rods (0.5–0.8×2–8 μm) that were motile by means of lateral flagella. Cells were oxidase negative, but catalase positive and possessed a b-type cytochrome(s) associated with the cell membrane. Cells grew anaerobically with H2+CO2 as energy source and catalyzed a total synthesis of acetate from this gas mixture. H2 uptake by a representative isolate (strain JSN-2) displayed a Km=6 μM and Vmax=380 nmol x min-1 x mg protein-1. Other substrates used as energy sources for growth and acetogenesis included CO, methanol, betaine, trimethoxybenzoate, and various other organic acids. Succinate was also fermented, but propionate was formed from this substrate instead of acetate. Of a variety of sugars and sugar alcohols tested, only mannitol supported growth. Cells grew optimally at 30° C and pH 7.2 and required yeast extract or a source of amino acids (e.g. Casamino acids) for good growth. During initial enrichment and isolation, cells appeared sensitive to various reducing agents commonly employed in media for anaerobes. The DNA base composition of strain JSN-2 was 48.6 mol% G+C. On the bases of cell morphology, substrate utilization spectrum, and DNA base composition, strain JSN-2 is here-with proposed as the type strain of the new species Sporomusa termitida.
TL;DR: The ability of bacteria to grow on low-molecular-weight lignin oligomers as the sole source of carbon and energy indicates that bacteria produce enzymes catalysing cleavage of intermonomeric linkages.
TL;DR: A second pathway for acetyl-CoA oxidation was found and it is shown that sulfur-reducing bacteria and one genus of sulfate reducers use a modified citric-acid cycle with a novel anaplerotic sequence as pathway of terminal respiration, while all other anaerobes use an alternative pathway.
Abstract: Many anaerobic bacteria can completely oxidize organic matter to CO2 with either sulfur, sulfate, or protons as electron acceptor The sulfur-reducing bacteria and one genus of sulfate reducers use a modified citric-acid cycle with a novel anaplerotic sequence as pathway of terminal respiration All other anaerobes use an alternative pathway, in which carbon monoxide dehydrogenase is a key enzyme and in which acetyl-CoA is cleaved into two C1 units at the oxidation level of CH3OH and CO Thus almost 50 years after the discovery of the citric acid cycle by Hans Krebs in 1937, a second pathway for acetyl-CoA oxidation was found
TL;DR: Evidence from scanning electron microscopy pointed to a general lack of colonization of the gut wall: instead, microorganisms were abundant in the intestinal contents, and aerobic bacteria were generally resistant to the antibiotics in use.
Abstract: Populations of aerobic and anaerobic heterotrophic bacteria occurring in the gastrointestinal tract of healthy rainbow trout were estimated using a dilution plate technique. Data revealed a progressive decline in numbers of aerobic bacteria along the digestive tract from oesophagus to lower intestine. However, the highest numbers were recovered from the intestinal contents and faeces. Anaerobes were generally restricted to the upper intestine and intestinal contents. The aerobic component of the bacterial microflora from the digestive tract was equated with Acinetobacter calcoaceticus, Aeromonas hydrophila, Bacillus circulans, Bac. megaterium, coryneforms, Grampositive irregularly shaped rods, Flavobacterium sp., Kurthia sp., Microhacterium sp., Providencia stuartii, Pseudomonas spp., Ps.fluorescens and Ps. pseudoalcaligenes. Evidence from scanning electron microscopy pointed to a general lack of colonization of the gut wall: instead, microorganisms were abundant in the intestinal contents. Antimicrobial compounds, i.e. oxolinic acid, oxytetracycline and sulphafurazole (which are commonly used to combat infections by Gramnegative bacterial fish pathogens), caused an increase in bacterial numbers throughout the digestive tract, with maximal numbers in the lower intestine. The bacteria, comprising an essentially different range of taxa, were generally resistant to the antibiotics in use. Conversely, erythromycin and penicillin G, which are used to treat some diseases caused by Gram-positive bacteria, caused a rapid reduction in bacterial numbers within the gastrointestinal tract.
TL;DR: In this article, the importance of urease to bacteria is discussed, identifying the gastrointestinal tract as a major reservoir of Ureolytic bacteria and investigating the urinary tract environment and the infectious struvite stone production that often accompanies Urease-producing bacteria there.
Abstract: Urease activity is a physiological function of many bacteria that enables these organisms to utilize urea as a source of nitrogen. The association of ureolytic bacteria with human or animal hosts varies widely from a commensal relationship as demonstrated with skin microflora, a symbiotic relationship in the gastrointestinal tract, to a pathogenic relationship in the urinary tract. Since similar or identical species of bacteria such as Staphylococcus aureus are found in all three environments, the effect of urease activity on the host must be solely a function of the environment of these organisms. In this review, the importance of urease to bacteria is discussed, identifying the gastrointestinal tract as a major reservoir of ureolytic bacteria and investigating the urinary tract environment and the infectious struvite stone production that often accompanies urease-producing bacteria there. Finally, an infection model is presented which explains the development and growth of these urinary calculi and their remarkable persistence in spite of modern urological treatments.
TL;DR: It is concluded that the relative importance of bacteria and protozoa as nutrient regenerators in the detrital food loop is dependent largely on the overall carbon:nutrient ratio of the bacterial substrate.
Abstract: We have used a model food chain composed of a natural bacterial assemblage, a pennate diatom and a bacterivorous microflagellate to investigate the factors controlling the relative importance of bacteria and protozoa as sources for regenerated nitrogen in plankton communities. In bacterized diatom cultures in which diatom growth was nitrogen-limited, the carbon:nitrogen (C:N) ratio of the bacterial substrate greatly affected which population was responsible for the uptake of nitrogen. When nitrogen was added as NH4+ and the cultures were supplemented with glucose, the bacteria competed successfully with the algae for NH4+ and prevented the growth of algae by rapidly assimilating all NH4+ in the cultures. Bacterivorous protozoa inoculated into these cultures grazed the bacterial population and remineralized NH4+, thus relieving the nitrogen limitation of algal growth and allowing an increase in algal biomass. In contrast, bacteria in cultures supplemented with the amino acid glycine (C:N = 2) were major remineralizers of nitrogen, and the influence of protozoan grazing was minimal. We conclude that the relative importance of bacteria and protozoa as nutrient regenerators in the detrital food loop is dependent largely on the overall carbon:nutrient ratio of the bacterial substrate. The role of bacterivorous protozoa as remineralizers of a growth-limiting nutrient is maximal in situations where the carbon:nutrient ratio of the bacterial substrate is high.
TL;DR: This antibiotic shows remarkable activity in spermatogonial assay and potent cytotoxicity against KB carcinoma cells in vitro, and exhibits inhibition on transplantable tumors in mice.
Abstract: Strain C-1027, an actinomycete isolated from a soil sample collected in China, was found to produce the new antibiotic, C-1027. From taxonomical studies on its morphological, cultural and physiological characteristics, this antibiotic-producing strain was identified as Streptomyces globisporus C-1027. Antibiotic C-1027 has antimicrobial activity against most Gram-positive bacteria but not against Mycobacterium sp. or Gram-negative bacteria. This antibiotic shows remarkable activity in spermatogonial assay and potent cytotoxicity against KB carcinoma cells in vitro, and exhibits inhibition on transplantable tumors in mice.
TL;DR: The gut may be a reservoir or source of bacterial peptides that could promote an inflammatory response should they cross the 'mucosal barrier', and pronase-sensitive bioactive factors have been demonstrated in human rectal dialysates from normal subjects and patients with Crohn's disease.
Abstract: Chadwick VS, Mellor DM, Myers DB, Selden AC, Keshavarzian A, Broom MF, Hobson CH. Production of peptides inducing chemotaxis and lysosomal enzyme release in human neutrophils by intestinal bacteria in vitro and vivo.Low molecular weight (MI 200-1500) N-formylated peptides that stimulate many leucocyte functions, including chemotaxis and lysosomal enzyme release, have previously been isolated from Escherichia coli cultures. We have used high-performance liquid chromatography and bioassay techniques to study production of such peptides by intestinal bacteria in vitro and their activity in intestinal luminal contents, obtained by in vivo dialysis methods. Bioactivity was detected in culture supernatants of all 11 species of bacteria so far investigated, was resistant to digestion with amino-peptidase, but was destroyed by carboxypeptidase, confirming that bioactive moieties were amino-terminal-blocked peptides. By similar isolation procedures, pronase-sensitive bioactive factors have been demonstrated in hum...
TL;DR: Vancomycin-resistant gram-positive bacteria may represent an emerging class of nosocomial pathogens and better methods for distinguishing the various genera in the clinical microbiology laboratory are needed.
Abstract: Recent reports of infections with vancomycin-resistant gram-positive bacteria prompted us to study vancomycin-resistant isolates from human sources to characterize the types of bacteria displaying this phenotype. Thirty-six vancomycin-resistant gram-positive isolates, 14 from clinical specimens and 22 from stool samples, were identified. These isolates were tentatively identified as Lactobacillus spp. (25 strains), Leuconostoc spp. (6 strains), and Pediococcus spp. (3 strains) on the basis of morphology and physiological tests. Two isolates of indeterminate morphology could not be unambiguously assigned to a genus. Four isolates of vancomycin-resistant lactobacilli from normally sterile body sites were considered to be clinically significant. Vancomycin-resistant gram-positive bacteria may represent an emerging class of nosocomial pathogens. Better methods for distinguishing the various genera in the clinical microbiology laboratory are needed.
01 Jan 1988
TL;DR: C.W. Jones, Membrane-Associated Energy Conservation in Bacteria: A General Introduction.
Abstract: C.W. Jones, Membrane-Associated Energy Conservation in Bacteria: A General Introduction. W.A. Hamilton, Energy Transduction in Anaerobic Bacteria. S.J. Ferguson, Periplasmic Electron Transport Reactions. P.M. Wood, Chemolithotrophy. R.K. Poole, Bacterial Cytochrome Oxidases. C. Anthony, Quinoproteins and Energy Transduction. J.B. Jackson, Bacterial Photosynthesis. I.R. Booth, Bacterial Transport: Energetics and Mechanisms. D.B. Kell, Protonmotive Energy-Transducing Systems: Some Physical Principles and Experimental Approaches.
TL;DR: The results indicate that anaerobic bacteria play a pivotal role in limiting the translocation of normal intestinal bacteria, but that other bacterial groups also have a role in preventing the intestinal colonization and translocated of potential pathogens.
Abstract: The purpose of this study was to clarify the role of the intestinal anaerobe bacteria in colonization resistance. Germfree mice were associated with Escherichia coli C25 and either (a) no other species; (b) enterococcus; (c) Escherichia coli M14 and Proteus mirabilis, or (d) Bacteroides fragilis and Bacteroides vulgatus. All species colonized the cecum in high numbers, but only enterococcus significantly limited the translocation of Escherichia coli C25 to mesenteric lymph nodes. However, the overall translocation rates were similar in all groups and ranged from 60% to 100%, due to translocation of other intestinal flora in addition to Escherichia coli C25. Conventionally reared mice were given either streptomycin, bacitracin/streptomycin or metronidazole which selectively eliminated facultative gram-negative bacteria, nearly all bacterial species or strictly anaerobic bacteria respectively. Only metronidazole significantly increased the rates of translocation of normal intestinal bacteria into mesenteric lymph nodes. Cohort groups of mice were then orally inoculated with drug resistant Escherichia coli C25, which actively colonized the cecum of all drug treated mice and translocated to the mesenteric lymph nodes of approximately half the streptomycin and metronidazole treated mice and nearly all the bacitracin/streptomycin treated mice. These results indicate that anaerobic bacteria play a pivotal role in limiting the translocation of normal intestinal bacteria, but that other bacterial groups also have a role in preventing the intestinal colonization and translocation of potential pathogens.
TL;DR: The interactions between lactic acid bacteria and their phages are commercially significant, and preliminary studies suggest the operation of mechanisms such as the prevention of phage adsorption, restriction/modification, and abortive infection.
TL;DR: In addition to ethanol, the fermentation of grape must by yeasts produces fatty acids as secondary metabolites which inhibit growth of lactic acid bacteria.
Abstract: In addition to ethanol, the fermentation of grape must by yeasts produces fatty acids as secondary metabolites which inhibit growth of lactic acid bacteria. The degree of inhibition depends upon the fatty acid concentration and chain length and on the composition of the medium.
TL;DR: Seven bacteria representing seven genera of enteric bacteria, in addition to Escherichia coli, were shown to reduce nitrite to NO under anaerobic conditions when the cells were grown as nitrate respirers, just as was found to be the case previously with E. coli.
TL;DR: 16 bacterial strains were isolated which utilize quinoline as sole carbon and nitrogen source and could be identified as members of the genus Pseudomonas, three strains show a positive Gram strain and were identified as Rhodococcus species.
TL;DR: It is suggested that pili and flagella each play an important role as virulence factors independently, and that pil‐mediated enhancement of virulence of P. aeruginosa was attributed to pili‐mediated enhanced colonization of the organisms at the burned skin surfaces.
Abstract: The present study using three isogenic mutants (F+P-, F-P+, F-P-) of Pseudomonas aeruginosa indicates that the presence of pili enhances the virulence of the organisms in experimental P. aeruginosa burn infection of mice. The 50% lethal dose (LD50) value for burned mice inoculated with non-piliated (P-) mutant was at least ten times higher than those inoculated with piliated (P+) bacteria. Meanwhile the LD50 value for burned mice inoculated with non-flagellated (F-) mutant was at least 10(5) times higher than those inoculated with flagellated (F+) bacteria. At 24 hr after inoculation, the bacterial counts in burned skin of mice inoculated with P+ bacteria were ten times higher than those inoculated with P- bacteria; and at 48 hr the bacterial counts became a hundred times higher in the former mice than the latter. At 24 hr after inoculation, P+ bacteria were isolated from blood, liver (F+P+), lung (F+P+), and kidney, while P- bacteria were not present in these tissues. And at 48 hr after inoculation, P+ bacteria were isolated from all tissues, while P- bacteria were isolated from some sites only. These results suggested that pili and flagella each play an important role as virulence factors independently, and that pili-mediated enhancement of virulence of P. aeruginosa was attributed to pili-mediated enhanced colonization of the organisms at the burned skin surfaces.
TL;DR: It is demonstrated that many humans harbor intestinal cellulolytic bacteria and that a hydrated cellulose source such as AHP-WS is necessary for their consistent detection and isolation.
Abstract: The fibrolytic microbiota of the human large intestine was examined to determine the numbers and types of cellulolytic and hemicellulolytic bacteria present. Fecal samples from each of five individuals contained bacteria capable of degrading the hydrated cellulose in spinach and in wheat straw pretreated with alkaline hydrogen peroxide (AHP-WS), whereas degradation of the relatively crystalline cellulose in Whatman no. 1 filter paper (PMC) was detected for only one of the five samples. The mean concentration of cellulolytic bacteria, estimated with AHP-WS as a substrate, was 1.2 X 10(8)/ml of feces. Pure cultures of bacteria isolated on AHP-WS were able to degrade PMC, indicating that interactions with other microbes were primarily responsible for previous low success rates in detecting fecal cellulolytic bacteria with PMC as a substrate. The cellulolytic bacteria included Ruminococcus spp., Clostridium sp., and two unidentified strains. The mean concentration of hemicellulolytic bacteria, estimated with larchwood xylan as a substrate, was 1.8 X 10(10)/ml of feces. The hemicellulose-degrading bacteria included Butyrivibrio sp., Clostridium sp., Bacteroides sp., and two unidentified strains, as well as four of the five cellulolytic strains. This work demonstrates that many humans harbor intestinal cellulolytic bacteria and that a hydrated cellulose source such as AHP-WS is necessary for their consistent detection and isolation.