Showing papers on "Bacteria published in 1984"
369 citations
363 citations
TL;DR: In this article, Vibrio harveyi, a marine, aerobic, heterotrophic bacterium, was cultured on individual compounds each containing carbon and nitrogen, and when grown on different substrates, the bacteria fractionated the isotopes uniquely.
361 citations
TL;DR: The results indicate that gene 2 of the T region, which participates in tumorous growth of plant cells, codes both in bacteria and in plants for an amidohydrolase involved in the biosynthesis of the plant hormone indole-3-acetic acid.
Abstract: Gene 2 from the T region of Ti plasmids appears to be expressed both in eucaryotic and in procaryotic systems. In transformed plant cells it participates in auxin-controlled growth and differentiation, and in bacteria it is expressed into a defined protein of Mr 49000. We investigated the possibility that it codes for an enzyme involved in auxin biosynthesis.
Only extracts from Escherichia coli cells expressing gene 2 hydrolyzed indole-3-acetamide into a substance which was unambiguously identified as indole-3-acetic acid. The same reaction was found in Agrobacteria containing gene 2, but not in strains lacking the gene. Extracts from tobacco crown gall cells, but not from non-transformed cells, showed the same enzyme activity, and the reaction product was also identified as indole-3-acetic acid. The results indicate that gene 2 of the T region, which participates in tumorous growth of plant cells, codes both in bacteria and in plants for an amidohydrolase involved in the biosynthesis of the plant hormone indole-3-acetic acid.
358 citations
TL;DR: A mutualism among at least the dechlorinating, benzoate-oxidizing, and methane-forming members was apparently required for utilization of the 3-chlorobenzoate substrate.
Abstract: A methanogenic consortium able to use 3-chlorobenzoic acid as its sole energy and carbon source was enriched from anaerobic sewage sludge. Seven bacteria were isolated from the consortium in mono- or coculture. They included: one dechlorinating bacterium (strain DCB-1), one benzoate-oxidizing bacterium (strain BZ-2), two butyrate-oxidizing bacteria (strains SF-1 and NSF-2), two H(2)-consuming methanogens (Methanospirillum hungatei PM-1 and Methanobacterium sp. strain PM-2), and a sulfate-reducing bacterium (Desulfovibrio sp. strain PS-1). The dechlorinating bacterium (DCB-1) was a gram-negative, obligate anaerobe with a unique "collar" surrounding the cell. A medium containing rumen fluid supported minimal growth; pyruvate was the only substrate found to increase growth. The bacterium had a generation time of 4 to 5 days. 3-Chlorobenzoate was dechlorinated stoichiometrically to benzoate, which accumulated in the medium; the rate of dechlorination was ca. 0.1 pmol bacterium day. The benzoate-oxidizing bacterium (BZ-2) was a gram-negative, obligate anaerobe and could only be grown as a syntroph. Benzoate was the only substrate observed to support growth, and, when grown in coculture with M. hungatei, it was fermented to acetate and CH(4). One butyrate-oxidizing bacterium (NSF-2) was a gram-negative, non-sporeforming, obligate anaerobe; the other (SF-1) was a gram-positive, sporeforming, obligate anaerobe. Both could only be grown as syntrophs. The substrates observed to support growth of both bacteria were butyrate, 2-dl-methylbutyrate, valerate, and caproate; isobutyrate supported growth of only the sporeforming bacterium (SF-1). Fermentation products were acetate and CH(4) (from butyrate, isobutyrate, or caproate) or acetate, propionate, and CH(4) (from 2-dl-methylbutyrate or valerate) when grown in coculture with M. hungatei. A mutualism among at least the dechlorinating, benzoate-oxidizing, and methane-forming members was apparently required for utilization of the 3-chlorobenzoate substrate.
342 citations
TL;DR: The therapeutic efficacies of TE-031 and TE-032 against systemic and subcutaneous infections provoked by Gram-positive bacteria in mice are 4- to 35-fold superior to those of EM and JM.
Abstract: The in vitro and in vivo antibacterial activities of 6-O-methylerythromycin A (TE-031, A-56268, or clarithromycin) and 6, 11-di-O-methylerythromycin A (TE-032) have been compared with those of erythromycin A (EM) and josamycin (JM). TE-031 and TE-032, having the same antibacterial spectra as EM, are active against aerobic Gram-positive bacteria, some Gram-negative bacteria, anaerobic bacteria, L-form bacteria and Mycoplasmapneumoniae. The activity of TE-031 against clinical isolates is equal to or two times more potent than that of EM, whereas TE-032 is slightly less active than EM. The activities of TE-031 and TE-032 are pH dependent (more active at pH 8 than at 5) and are increased by adding serum to medium. TE-031 and TE-032 show dose-related bactericidal activities against Haemophilus influenzae. The therapeutic efficacies of TE-031 and TE-032 against systemic and subcutaneous infections provoked by Gram-positive bacteria in mice are 4- to 35-fold superior to those of EM and JM. TE-031 and TE-032 have demonstrated higher and longer-lasting plasma levels than EM when administered orally to mice, rats or dogs.
250 citations
TL;DR: Results suggest that simultaneous selection phenomena occurred in distribution water for bacteria which exhibited unique patterns of tolerance to Cu2+, Pb2+, and Zn2+ and antibiotic resistance.
Abstract: Bacterial isolates from the drinking water system of an Oregon coastal community were examined to assess the association of metal tolerance with multiple antibiotic resistance. Positive correlations between tolerance to high levels of Cu2+, Pb2+, and Zn2+ and multiple antibiotic resistance were noted among bacteria from distribution waters but not among bacteria from raw waters. Tolerances to higher levels of Al3+ and Sn2+ were demonstrated more often by raw water isolates which were not typically multiple antibiotic resistant. A similar incidence of tolerance to Cd2+ was demonstrated by isolates of both water types and was not associated with multiple antibiotic resistance. These results suggest that simultaneous selection phenomena occurred in distribution water for bacteria which exhibited unique patterns of tolerance to Cu2+, Pb2+, and Zn2+ and antibiotic resistance.
231 citations
TL;DR: The results obtained suggest that virulence of axenically grown E. histolytica trophozoites may depend to a considerable extent on the cell's reducing power, and both microaerobic conditions and the association with bacteria apparently stimulate the electron transport system of the ameba.
Abstract: The association of axenically grown trophozoites of Entamoeba histolytica strains HK-9 or HM-1:IMSS with various types of gram-negative bacteria for relatively short periods markedly increased their virulence, as evidenced by their ability to destroy monolayers of tissue-cultured cells. Interaction of trophozoites with bacteria that were heat inactivated, glutaraldehyde fixed, or disrupted by sonication, or bacteria treated with inhibitors of protein synthesis, did not augment amebic virulence. Lethally irradiated bacteria, however, retained their stimulative properties and trophozoites that ingested bacteria were protected from the toxic effects of added hydrogen peroxide. An increase in virulent properties of amebae was also found in experiments carried out under microaerobic conditions (5% O2, 10% CO2). The augmentation of amebic virulence due to association with bacteria was specifically blocked by metronidazole, but not by tetracycline or aminoglycosides, and the rate of metronidazole uptake in stimulated trophozoites was two to three times higher. The results obtained suggest that virulence of axenically grown E. histolytica trophozoites may depend to a considerable extent on the cell's reducing power. Both microaerobic conditions and the association with bacteria apparently stimulate the electron transport system of the ameba. Bacteria may function as broad range scavengers for oxidized molecules and metabolites through the contribution of enzymatic systems, components, or products.
188 citations
TL;DR: Six strains of strictly thermophilic, obligately chemolithotrophic, hydrogen-oxidizing bacteria were isolated from hot springs located in Izu and Kyushu, Japan and no strain showed heterotrophic growth at the expense of 48 organic compounds or on complex media, in contrast to all other known aerobic hydrogen- oxidizingacteria which are facultative autotrophs.
Abstract: Six strains of strictly thermophilic, obligately chemolithotrophic, hydrogen-oxidizing bacteria were isolated from hot springs located in Izu and Kyushu, Japan. The bacterial strains which we tested were gram negative, nonmotile, nonsporeforming, long, straight, and rod shaped. The cell size was 0.3 to 0.5 by 2.0 to 3.0 μm. The deoxyribonucleic acid guanine-plus-cytosine contents of the six strains were between 43.5 and 43.9 mol%. The optimal temperature for autotrophic growth on H2-O2-CO2 was between 70 and 75°C. None of the strains grew at 37 or 80°C. The neutral pH range was suitable for growth. No strain showed heterotrophic growth at the expense of 48 organic compounds or on complex media, in contrast to all other known aerobic hydrogen-oxidizing bacteria which are facultative autotrophs. The major cellular fatty acids were a straight-chain saturated C18:0 acid and a straight-chain unsaturated C20:1 acid with one double bond. C16:0 and C18:1 fatty acids and a C21:0 cyclopropane acid were minor components. Cytochromes b and c were found in all of the strains. The polyacrylamide gel electrophoretic patterns of the total soluble proteins of all of the strains were essentially the same. The name Hydrogenobacter thermophilus gen. nov., sp. nov., is proposed for the six new isolates, and type strain TK-6 has been deposited with the culture collection of the Institute of Applied Microbiology, University of Tokyo, as strain IAM 12695.
181 citations
TL;DR: The data indicate that these bacteria lack an ordinary Gram-negative type of murein and, instead, carry a stable protein envelope and showed considerable resistance against penicillin G, ampicillin, cephalotin and D-cycloserin.
Abstract: Seven strains of budding, non-prosthecate bacteria belonging to the Planctomyces/Pasteuria group and a Prosthecomicrobium sp. were examined for muramic and diaminopimelic acids. These typical components of Gram-negative murein were found only in Prosthecomicrobium strain IFAM 1314, but they could not be detected in seven budding bacteria. Electron micrographs of ultrathin cell wall sections of strains IFAM 1313 and 1317 showed a membrane with bilayer structure outside the cytoplasmic membrane. 10% sodium dodecylsulfate treatment (30 min, 100°C) allowed the isolation of highly stable cell sacculi which, upon chemical analysis, proved to be mainly proteinaceous. The budding bacteria also showed considerable resistance against penicillin G, ampicillin, cephalotin and D-cycloserin. Our data indicate that these bacteria lack an ordinary Gram-negative type of murein and, instead, carry a stable protein envelope.
144 citations
TL;DR: The results indicate that chlorination, while initially lowering the total number of bacteria in sewage, may substantially increase the proportions of antibiotic-resistant, potentially pathogenic organisms.
Abstract: A total of 1,900 lactose-fermenting bacteria were isolated from raw sewage influent and chlorinated sewage effluent from a sewage treatment plant, as well as from chlorinated and neutralized dilute sewage, before and after a 24-h regrowth period in the laboratory. Of these isolates, 84% were resistant to one or more antibiotics. Chlorination of influent resulted in an increase in the proportion of bacteria resistant to ampicillin and cephalothin, the increase being most marked after regrowth occurred following chlorination. Of the other nine antibiotics tested, chlorination resulted in an increased proportion of bacteria resistant to some, but a decrease in the proportion resistant to the remainder. Multiple resistance was found for up to nine antibiotics, especially in regrowth populations. Identification of about 5% of the isolates showed that the highest proportion of Escherichia coli fell in untreated sewage. Some rare and potentially pathogenic species were isolated from chlorinated and regrowth samples, including Yersinia enterocolitica, Yersinia pestis, Pasteurella multocida, and Hafnia alvei. Our results indicate that chlorination, while initially lowering the total number of bacteria in sewage, may substantially increase the proportions of antibiotic-resistant, potentially pathogenic organisms.
TL;DR: The hydrogenation of α-linolenic acid to stearic acid which occurs with the mixed bacteria of the sheep rumen can be demonstrated in vitro by mixing exponential phase cultures of only two species of rumen bacteria and incubating for a further period with α-Linolenic Acid.
Abstract: The hydrogenation of α-linolenic acid to stearic acid which occurs with the mixed bacteria of the sheep rumen can be demonstrated in vitro by mixing exponential phase cultures of only two species of rumen bacteria and incubating for a further period with α-linolenic acid. One bacterium must be able to hydrogenate α-linolenic acid to predominantly trans-octadec-11-enoic acid which is then used 11 substrate by a second bacterium. Cultures grown from small mixed inocula failed, with the exception of one pair of bacteria, to hydrogenate α-linolenic acid to stearic acid. The products from these cultures showed that one of the pair of bacteria had outgrown the other. For stearate production it was necessary to use inocula with a minimum number of cells rather than cells in a particular phase of growth. Two of the bacteria used, P2/2 and T344, after several years in pure culture show an increased isomerization of the octadecenoic acid products.
TL;DR: Actinoplanes sp. ATCC 33076 is a new strain that was found to produce an antibiotic, designated A-16686, which is a complex of three closely-related polypeptides containing chlorinated phenyl moieties and D-mannose as mentioned in this paper.
Abstract: Actinoplanes sp. ATCC 33076 is a new strain that was found to produce an antibiotic, designated A-16686, which is a complex of three closely-related polypeptides containing chlorinated phenyl moieties and D-mannose. Both the complex and the single fractions possess a good activity against Gram-positive bacteria. A-16686 specifically inhibits the synthesis of the bacterial cell wall.
TL;DR: Although sponges do have mechanisms to ingest particles such as food, they appear to be unable to consume bacterial symbionts, probably because their identity is masked by capsular sheaths.
Abstract: This study considered whether marine sponges are selective particle feeders, and whether they are capable of distinguishing between sponge bacterial symbionts and other bacteria. Four species of marine sponges (Aplysina aerophoba, A. cavernicola, Pericharax heteroraphis and Spongia sp.) were fed in situ with tritium-labelled bacteria, either symbionts or other bacteria isolated from seawater. A large proportion of bacterial symbionts passed through the sponge and were expelled in the exhalant current, whereas seawater bacteria disappeared from the incubation water and were retained within the sponge. The seawater bacteria were observed in choanocytes and occasionally in pinacocytes after 30-40 min, whereas symbiont bacteria were rarely observed. Although sponges do have mechanisms to ingest particles such as food, they appear to be unable to consume bacterial symbionts, probably because their identity is masked by capsular sheaths. A specific mechanism for recognition and rejection of self-particulate matter is proposed for sponge epidermal cells.
TL;DR: The results establish a model system for the anaerobic, rapid, and complete oxidation of an aminoaromatic compound.
Abstract: In the presence of oxygen many aminoaromatic compounds polymerize to form recalcitrant macromolecules. To circumvent undesirable oxidation reactions, the anaerobic biodegradation of a simple member of this class of compounds was investigated. Two strains of bacteria were isolated which degrade 2-aminobenzoate anaerobically under denitrifying conditions, with nitrate as the terminal electron acceptor. Both organisms, which were assigned to the genus Pseudomonas, oxidized 2-aminobenzoate completely to CO2 and NH4+. Nitrate was reduced to nitrite. When nitrate was deplete from the growth medium the accumulated nitrite was reduced to nitrogen. The results establish a model system for the anaerobic, rapid, and complete oxidation of an aminoaromatic compound.
TL;DR: It was found that the affinity for sulfide is higher in those phototrophic bacteria that deposit elemental sulfur outside the cells, than in those bacteria that store the sulfur inside the cells.
Abstract: Seventeen strains of phototrophic bacteria (4 strains of Chromatium spp., 2 strains of Thiocapsa sp., 4 strains of Ectothiorhodospira spp., 2 strains of Rhodopseudomonas sp., and 5 strains of Chlorobium spp.) have been grown in sulfide-limited continuous cultures to assess the affinity for sulfide. It was found that the affinity (calculated as the initial slope of the specific growth rate versus the concentration of sulfide) is higher in those phototrophic bacteria that deposit elemental sulfur outside the cells, than in those bacteria that store the sulfur inside the cells. A hypothesis is presented to explain this correlation.
TL;DR: It is hypothesized that these varying states of modification in Salmonella bacteria grown under different physiological conditions are related to electron-acceptor pathways in anaerobic or aerobic growth.
TL;DR: lipid A of other gram-negative bacteria was analysed for the presence of amide-bound 3-acyloxyacyl residues and it was found that such residues are constituents of all lipid A tested.
Abstract: It has previously been demonstrated [Eur. J. Biochem. 124, 191-198 (1982) and 137, 15-22 (1983)] that the lipid A component of Salmonella and Proteus lipopolysaccharides contains amide-linked (R)-3-acyloxyacyl residues. In the present study lipid A of other gram-negative bacteria was analysed for the presence of amide-bound 3-acyloxyacyl residues. It was found that such residues are constituents of all lipid A tested (Agrobacterium tumefaciens, Chromobacterium violaceum, Pseudomonas aeruginosa, Xanthomonas sinensis, Bacteroides fragilis, Vibrio cholerae, Fusobacterium nucleatum, Rhodospirillum tenue, Acinetobacter calcoaceticus, and Escherichia coli). Amide-linked (R)-3-acyloxyacyl groups, therefore, represent common and ubiquitous structural elements of bacterial lipid A. The composition of 3-acyloxyacyl groups differed considerably among different bacteria. As amide-bound (R)-3-hydroxy fatty acids straight chain and isobranched acyl groups with 10-17 carbon atoms were identified. The most frequently encountered fatty acids, substituting the 3-hydroxyl group of 3-hydroxy fatty acids, were nonhydroxylated straight chain and isobranched acyl residues with 10-17 carbon atoms as well as (S)-2-hydroxy fatty acids with 12 carbon atoms. In some cases, using laser desorption mass spectrometry, the distribution of 3-acyloxyacyl residues over the two available glucosamine amino groups of the lipid A backbone was investigated.
TL;DR: These bacteria are polarly flagellated, gram-negative, nonsporeforming, rod-shaped organisms that occur singly and in pairs and haveCarotenoid pigment and bacteriochlorophyll are formed in the cells.
Abstract: A new genus and species of facultatively methylotrophic bacteria are described. These bacteria are polarly flagellated, gram-negative, nonsporeforming, rod-shaped organisms that occur singly and in pairs. Carotenoid pigment and bacteriochlorophyll are formed in the cells. The deoxyribonucleic acid base composition is 65 to 67 mol% guanine plus cytosine. The cellular fatty acids consist of a large amount of straight-chain unsaturated C18:1 acid and small amounts of straight-chain saturated C16:1 acid, C19:0 cyclopropane acid, and 3-OH-C14:0 hydroxy acid. The major ubiquinone is Q-10. Ubiquinones Q-8, Q-9, and Q-11 are present as minor components. A new genus, Protomonas, is proposed to include this group of methylotropic bacteria. The type species of the genus Protomonas is Protomonas extorquens comb. nov., with type strain TK 0001 (=DSM 1337 = NCIB 9399).
01 Jul 1984
TL;DR: In this article, two strains of Pseudomonas were isolated which degraded 2-aminobenzoate anaerobically under denitrifying conditions, with nitrate as the terminal electron acceptor.
Abstract: In the presence of oxygen many aminoaromatic compounds polymerize to form recalcitrant macromolecules. To circumvent undesirable oxidation reactions, the anaerobic biodegradation of a simple member of this class of compounds was investigated. Two strains of bacteria were isolated which degrade 2-aminobenzoate anaerobically under denitrifying conditions, with nitrate as the terminal electron acceptor. Both organisms, which were assigned to the genus Pseudomonas, oxidized 2-aminobenzoate completely to CO/sub 2/ and NH/sub 4//sup +/. Nitrate was reduced to nitrite. When nitrate was depleted from the growth medium the accumulated nitrite was reduced to nitrogen. The results establish a model system for the anaerobic, rapid, and complete oxidation of an aminoaromatic compound.
TL;DR: Several pathogenic strains of Escherichia coli isolated from chickens and turkeys with severe colisepticemia had thin pili (fimbriae) that facilitated adherence of the bacteria to chick tracheal epithelial cells both in vitro and in vivo.
Abstract: SUMMARY Several pathogenic strains of Escherichia coli were isolated from chickens and turkeys with severe colisepticemia. Electron microscopic examination showed that all these strains had thin pili (fimbriae) when grown at 37 C but not at 18 C. These pili facilitated adherence of the bacteria to chick tracheal epithelial cells both in vitro and in vivo. The role of these pili in pathogenicity was examined by comparing chicks infected intratracheally with piliated bacteria and chicks infected with non-piliated bacteria. The presence of adherence pili on the infecting bacteria affected both the number of chicks that developed disease and the severity of the disease. RESUMEN
TL;DR: When contaminated shoot cultures of apple and rhododendron were treated with cefotaxime, tetracycline, rifampicin, and polymyxin B in combination at 25, 25, 6 and 6 mg/l, respectively, the bacteria were completely eliminated.
TL;DR: Phenanthrene-degrading bacteria were isolated from Chesapeake Bay samples by the use of a solid medium which had been overlaid with an ethanol solution of phenanthrene before inoculation and identified as Vibrio parahaemolyticus and VIBrio fluvialis.
Abstract: Phenanthrene-degrading bacteria were isolated from Chesapeake Bay samples by the use of a solid medium which had been overlaid with an ethanol solution of phenanthrene before inoculation. Eighteen representative strains of phenanthrene-degrading bacteria with 21 type and reference bacteria were examined for 123 characteristics representing physiological, biochemical, and nutritional properties. Relationships between strains were computed with several similarity coefficients. The phenogram constructed by unweighted-pair-group arithmetic average linkage and use of the simple Jaccard (SJ) coefficient was used to identify seven phena. Phenanthrene-degrading bacteria were identified as Vibrio parahaemolyticus and Vibrio fluvialis by their clustering with type and reference strains. Several phenanthrene-degrading bacteria resembled Enterobacteriaceae family members, although some Vibrio-like phenanthrene degraders could not be identified.
Patent•
24 Feb 1984TL;DR: The use of this dul-purpose promoter region to drive expression of a single copy of a foreign structural gene in both plants and bacteria was demonstrated in this article, where the construction of a selectable marker functional in eukaryotes and prokaryotes is exemplified, as are vectors useful in efforts to transform plants.
Abstract: A promoter region that drives expression of a 1450 base T R transcript in octopine-type crown gall tumors can also promote expression of a foreign structural gene in bacteria. Use of this dul-purpose promoter region to drive expression of a single copy of a foreign structural gene in both plants and bacteria is taught. The construction of a selectable marker functional in eukaryotes and prokaryotes is exemplified, as are vectors useful in efforts to transform plants.
Book•
04 Jan 1984
TL;DR: The Cell Envelope in Bacterial Disease, the Bacterial Cell Surface in Relation to the Environment, and the Peptidoglycan Layer are studied.
Abstract: 1. The Peptidoglycan Layer.- 2. Walls of Gram-positive Bacteria.- 3. The Envelope of Gram-negative Bacteria.- 4. Surface Appendages: Flagella and Fimbriae.- 5. The Cell Envelope in Bacterial Disease.- 6. The Bacterial Cell Surface in Relation to the Environment.
TL;DR: Cytotoxicity to phagocytes, which is mediated by or closely linked genetically to alpha-hemolysin, may be a mechanism by which alpha- Hemolytic strains of E. coli strengthen their ability to establish and maintain infections.
Abstract: The cytotoxic effect of Escherichia coli bacteria on human blood granulocytes was measured by recording numbers of nonlysed cells and percentages of viable cells after in vitro incubation with bacteria in the presence of plasma. A total of 179 strains from various sources of infection were tested. Of 117 alpha-hemolytic strains, 59 were cytotoxic. Five nonhemolytic mutant strains, derived from alpha-hemolytic cytotoxic strains, were nontoxic. None of the 62 nonhemolytic strains were toxic. Four spontaneously occurring alpha-hemolytic, nontoxic mutant strains were isolated from cytotoxic ones. Cytotoxicity of bacteria reached a maximum after log-phase growth at 30 to 37 degrees C for 2.5 h, and the toxic capacity was equal after growth in various media, including human urine and plasma. The cytotoxic effect increased with the length of exposure of granulocytes to bacteria and with increasing numbers of bacteria per granulocyte. Cytotoxic strains showed different degrees of toxicity, highly cytotoxic strains lysing about 90% of the granulocytes and killing about one-half of nonlysed cells in 1 h. Bacteria killed by heat, formaldehyde, or UV light were nontoxic. Alpha-hemolytic strains of O groups 2, 4, 6, 25, and 75 originating from various infections in humans were more frequently cytotoxic than alpha-hemolytic strains of other O groups derived from human infections. Culture supernatants containing free alpha-hemolysin were highly cytotoxic to human blood granulocytes, monocytes, and lymphocytes in vitro, whether supernatants originated from cytotoxic or noncytotoxic bacteria. Cytotoxicity to phagocytes, which is mediated by or closely linked genetically to alpha-hemolysin, may be a mechanism by which alpha-hemolytic strains of E. coli strengthen their ability to establish and maintain infections.
TL;DR: The mucin fermenters isolated by enrichment had a very restricted ability to utilize complex polysaccharides and their constituent monosaccharides, suggesting that the presence of plant polysacCharides in the human colon is unlikely to prevent the use of colonic mucin as an energy source by bacteria.
Abstract: Organisms able to grow on arabinogalactan, pectin, xylan, wheat bran, guar, apple cell walls, and mucin were isolated by enrichment from human feces. The number of polysaccharide fermenters and the properties of the predominant bacteria varied between subjects. The ability to use one polysaccharide was not related to the ability to use others. Some organisms (e.g., Bacteroides spp.) isolated on other substrates also utilized mucin, but were not isolated in the mucin enrichment. The mucin fermenters isolated by enrichment had a very restricted ability to utilize complex polysaccharides and their constituent monosaccharides, suggesting that the presence of plant polysaccharides in the human colon is unlikely to prevent the use of colonic mucin as an energy source by bacteria. Characterization with a range of biochemical tests showed that many of the isolates, but especially the mucin fermenters, did not resemble organisms described previously.
TL;DR: It is suggested that translocatable DNA elements encoding resistance to Hg2+ may be partly responsible for the dissemination and maintenance of the Hgr phenotype in microbial populations.
Abstract: A diverse population of bacteria, all with the common property of resistance to mercuric ions (Hg2+), was isolated from root-associated, and other soils. Each isolate was screened for its resistance to a variety of antibiotics and heavy metals as well as organomercurial compounds. Several isolates showed resistance values to individual antimicrobial agents that were significantly higher than the average resistance values with respect to those agents for the genus to which the isolate belonged. Of 76 distinct isolates tested, 4 were able to transfer the Hgr phenotype to sensitive cells at environmental temperatures. “Mobilization” of putative Hg-resistant non-conjugative plasmids with the wide host range plasmid RPl resulted in the co-transfer of the RPl markers and resistance to Hg2+ in 9 cases. Pl transduetion showed that 7 of these transfers were due, at least in part. to the formation of RPl-Hgr co-integrates. This suggests that translocatable DNA elements encoding resistance to Hg2+ may be partly responsible for the dissemination and maintenance of the Hgr phenotype in microbial populations.
TL;DR: In this paper, Cryptic Plasmids in Glutamic Acid-producing Bacteria (GABB) were found in the soil of the United States of America. Agricultural and Biological Chemistry: Vol. 48, No. 11, pp. 2901-2903.
Abstract: (1984). Cryptic Plasmids in Glutamic Acid-producing Bacteria. Agricultural and Biological Chemistry: Vol. 48, No. 11, pp. 2901-2903.