Showing papers on "Bacteria published in 1969"
TL;DR: Improved culture techniques for the cultivation of the more sensitive anaerobes have shown that no area of the gastrointestinal tract is sterile, that the predominant kinds of bacteria in the different areas of the tract are not the same, and that the bacteria inThe tract are metabolically active.
Abstract: Within the last few years, knowledge concerning anaerobic bacteria of man and other monogastric animals has increased and changed a great deal. With the development of improved culture techniques for the cultivation of the more sensitive anaerobes, it has become possible to study more effectively the anaerobic flora of man and other animals. Studies carried out with these methods have shown that no area of the gastrointestinal tract is sterile, that the predominant kinds of bacteria in the different areas of the tract are not the same, that the bacteria in the tract are metabolically active, and that the same species of anaerobic bacteria are also found, rather frequently, in infected tissue.
222 citations
TL;DR: Although the physiological characteristics of this organism differ markedly from other described species, it has been placed in the genus Peptostreptococcus on the basis of morphology, Gram stain, relations to oxygen, and the occurrence of cell division in only one plane.
Abstract: Thirty-two strains of pectin-fermenting rumen bacteria were isolated from bovine rumen contents in a rumen fluid medium which contained pectin as the only added energy source. Based on differences in morphology and the Gram stain, 10 of these strains were selected for characterization. Two strains were identified as Lachnospira multiparus, four strains were identified as Butyrivbrio fibrisolvens, and three strains were identified as Bacteroides ruminicola. Characteristics of the remaining strain did not correspond with any previously described species. It was a gram-positive anaerobic coccus, 1.0 to 1.2 μm in diameter, and occurred primarily as single cells or diplococci. The strain fermented pectin rapidly but showed little or no growth on any other energy sources tested. The only detectable end products were acetic acid and gas, a portion of which was identified as hydrogen. Although the physiological characteristics of this organism differ markedly from other described species, it has been placed in the genus Peptostreptococcus on the basis of morphology, Gram stain, relations to oxygen, and the occurrence of cell division in only one plane. End products of fermentation are somewhat similar to those of the cellulolytic ruminococci. Eight previously characterized strains of cellulolytic bacteria isolated in nonselective media were unable to ferment pectin, whereas ten strains of hemicellulolytic rumen bacteria, eight of which were isolated with a xylan medium, showed considerable variation in this characteristic.
137 citations
TL;DR: A mixture of hydrogen peroxide and ascorbic acid has been found to generate an antibacterial mechanism which is active against gram-negative bacteria and it is suggested that the effector mechanism involves the generation of short-lived free radicals which disturb the integrity of the cell wall.
Abstract: A mixture of hydrogen peroxide and ascorbic acid has been found to generate an antibacterial mechanism which is active against gram-negative bacteria. It results in bacterial death and renders the organism sensitive to lysis by lysozyme. Under the conditions used, horseradish peroxidase did not augment the antibacterial effect. It is suggested that the effector mechanism involves the generation of short-lived free radicals which disturb the integrity of the cell wall. This effect alone might kill bacteria by interfering with selective permeability, but in the presence of lysozyme a further bactericidal activity is accomplished by complete disruption of the cell. It is proposed that a transient antibacterial system such as that described could exist within phagocytic cells. Free radicals would be formed through the interaction of certain oxidizable substances and hydrogen peroxide, which is produced during the enhanced metabolic activity that accompanies ingestion of bacteria. Such a system would help to explain why macrophages, which are apparently devoid of preformed bactericidins, are nonetheless very efficient in killing most phagocytosed bacteria.
132 citations
Journal Article•
118 citations
TL;DR: The type and distribution of bacteria in the jejunal juice of patients with a variety of gastrointestinal conditions that might affect the small intestinal flora were examined and no simple correlation between the patient's fat excretion and bacterial colonization of the jejunum could be demonstrated.
Abstract: The type and distribution of bacteria in the jejunal juice of patients with a variety of gastrointestinal conditions that might affect the small intestinal flora were examined. Bacterial colonization of the jejunum defined, in this context, as the occurrence of a bile salttolerant flora consisting of both aerobic and anaerobic bacteria qualitatively resembling that of faeces, was observed only in patients with some form of blind loop. Prominent among the bacteria isolated from these colonized juices were non-sporing anaerobic bacteria, most usually Bacteroides, able to hydrolyse bile salts. No simple correlation between the patient's fat excretion and bacterial colonization of the jejunum could be demonstrated.
117 citations
TL;DR: Unlike other bacteria, Mycobacterium phlei elaborates a fatty acid synthetase of high molecular weight that requires a heat-stable factor and is inactivated in solutions of low ionic strength.
Abstract: Unlike other bacteria, Mycobacterium phlei elaborates a fatty acid synthetase of high molecular weight. This multienzyme complex requires a heat-stable factor and is inactivated in solutions of low ionic strength.
108 citations
TL;DR: The structural changes caused by Mg(++) deprivation appeared to involve specific and permanent alterations in membrane development, and the absence of other nutrients or divalent cations did not induce similar alterations.
Abstract: The effect of Mg(++) starvation on the structure of the Escherichia coli cell membrane was studied with the freeze-etch technique. Special attention was paid to changes within the plane of the membrane, which in normal exponentially growing cells has a netlike arrangement of particles 2 to 6 nm in diameter. During Mg(++) starvation, a paracrystalline particle pattern appeared on the plasma membrane, and large areas devoid of particles were seen. Although these changes are reproducibly associated with Mg(++) starvation of the bacteria, no decrease in the Mg(++) content of the cell envelope per se was detected, even after 24 hr of Mg(++) deprivation. The structural changes caused by Mg(++) deprivation appeared to involve specific and permanent alterations in membrane development. The absence of other nutrients or divalent cations did not induce similar alterations.
95 citations
TL;DR: Analyses, tests with isotopic nitrogen and tests for acetylene and isocyanide reduction, using both continuous and batch cultures, were made with seven strains of putative nitrogen-fixing bacteria and three local isolates, finding only two strains fixed nitrogen.
Abstract: SUMMARY: Analyses, tests with isotopic nitrogen and tests for acetylene and isocyanide reduction, using both continuous and batch cultures, were made with seven strains of putative nitrogen-fixing bacteria and three local isolates. Only two (single strains of Mycobacterium flavum and Pseudomonas azotogensis) fixed nitrogen; the active pseudomonad differed in several respects from the organism originally reported. Other Pseudomonas, Nocardia and Azotomonas species and the three local isolates did not fix; some simulated nitrogen fixation in cultural tests most impressively, but proved simply to be very efficient scavengers of traces of fixed nitrogen.
93 citations
TL;DR: A new genus, Agromyces, was proposed for filamentous, branching, catalase-negative bacteria that have an oxidative metabolism, are microaerophilic to aerobic, and contain neither diaminopimelic acid nor lysine as major constituents of the cell wall glycopeptide.
Abstract: The occurrence of filamentous, branching, catalase-negative bacteria as a numerically predominant microflora of various soils was demonstrated by using a dilution frequency isolation procedure. The major characteristics of these organisms were those of the order Actinomycetales. However, they could not be placed in any of the present genera of this order and, therefore, a new genus, Agromyces, was proposed for these organisms. This genus includes catalase-negative, nutritionally-fastidious microorganisms whose cells produce a true branching mycelium that fragments into coccoid and diphtheroid forms. Also, they have an oxidative metabolism, are microaerophilic to aerobic, and contain neither diaminopimelic acid nor lysine as major constituents of the cell wall glycopeptide. The type species would be Agromyces ramosus, gen. n., sp. n. The possible importance of these organisms in clarifying certain phylogenetic relationships of the Actinomycetales is discussed.
90 citations
TL;DR: Purification of the bacterial cells in a CsCl density gradient and other more conventional strain purification procedures both indicated that the presence of the satellite DNA component is not a result of mixed cultures.
Abstract: Bacteria classified as extreme halophiles, in the genera Halobacterium and Halococcus, contain deoxyribonucleic acid (DNA) which displays two components in a CsCl equilibrium density gradient. The base composition of the major DNA component ranges from 66 to 68% guanine plus cytosine (GC), whereas that of the satellite DNA comprising some 11 to 36% of the total, is between 57 and 60% GC. Purification of the bacterial cells in a CsCl density gradient and other more conventional strain purification procedures both indicated that the presence of the satellite DNA component is not a result of mixed cultures.
86 citations
TL;DR: DNA, isolated from bacteria which had been heated to 520 for several minutes, sedimented in an alkaline sucrose gradient more rapidly than DNA from untreated bacteria, in a similar manner to DNA from bacteria exposed to ionizing radiation.
Abstract: SUMMARY
DNA, isolated from bacteria which had been heated to 520 for several minutes, sedimented in an alkaline sucrose gradient more rapidly than DNA from untreated bacteria, in a similar manner to DNA from bacteria exposed to ionizing radiation. There is a general correlation between the sensitivities to γ- radiation and to incubation at 520 of various strains of Escherichia coli. Heated bacteria were more sensitive to subsequent exposure to γ-radiation, indicating that recovery capacity was itself heat-sensitive. The normal function of some of the cellular systems conferring radiation resistance might therefore be the mitigation of DNA damage due to mild thermal stress at elevated and perhaps also at normal temperatures.
TL;DR: This chapter traces the history and evidence for an evolutionary relationship between bacteria and mitochondria.
Abstract: Publisher Summary The mitochondrion is the only structure in the nucleated animal cell which satisfies both the biochemical and structural criteria for an evolutionary relationship with bacteria. Isolated mitochondria can perform most of the fundamental biochemical cycles necessary for independent life, including oxidative phosphorylation and protein, lipid, and nucleic acid synthesis. Despite this relative independence, mitochondria are essential structures of the eukaryotic cell. This chapter traces the history and evidence for an evolutionary relationship between bacteria and mitochondria. Mitochondria and bacteria are of similar shape and size and also there are similar cytochemical properties of mitochondria and some bacteria. One obvious difference between mitochondria and bacteria is their external envelopes. Bacteria are enclosed by a cell wall formed by enzymes located in the internal cytoplasmic membrane. Mitochondria are enclosed by two envelopes, both are membranous.
TL;DR: Antigens that determine agglutination reactions, and are distinct from the O-, H- and Vi-antigens, were demonstrated in the type-1 fimbriae of bacteria in fimbRIate-phase cultures of salmonellae.
Abstract: Summary Antigens that determine agglutination reactions, and are distinct from the O-, H- and Vi-antigens, were demonstrated in the type-1 fimbriae of bacteria in fimbriate-phase cultures of salmonellae. Most strains of salmonellae produced fimbriate cultures when grown for a sufficient period, e.g., 24–48 hr, at 37°C in aerobic static broth. The same strains produced non-fimbriate-phase cultures lacking fimbrial antigens when grown for only 6 hr in broth, for 12 hr in glucose broth or for 24 hr on an agar plate. The independence of the fimbrial antigens from the O-, H- and Vi-antigens was shown by the finding that an antiserum raised against a fimbriate-phase culture and freed from O-, H- and other non-fimbrial agglutinins by absorption with non-fimbriate-phase bacteria (“pure fimbrial antiserum”) strongly agglutinated fimbriate-phase bacteria, but did not agglutinate either non-fimbriate-phase bacteria or fimbriate bacteria that had been defimbriated by heating at 100°C. Crude (unabsorbed) and pure (absorbed) fimbrial antisera to strains of several salmonella serotypes agglutinated fimbriate-phase bacteria of a wide variety of heterologous serotypes. The reactions indicated the presence of a common fimbrial antigen in all of 95 fimbriate strains in 79 serotypes of Salmonella and two strains each of Arizona and Citrobacter. Absorption findings suggested that other fimbrial antigens were present in addition to the common one in strains of certain serotypes, but that the same antigens were present in different strains of the same serotype. A common fimbrial antigen was demonstrated in strains of Shigella flexneri, Escherichia coli and Klebsiella aerogenes, but there was no sharing of antigens between this group of bacteria and the salmonella-arizona-citrobacter group. Misleading cross-reactions may be obtained in diagnostic agglutination tests unless only non-fimbriate bacteria are used for the preparation of agglutinable suspensions and the production of diagnostic antisera. The development of cross-reacting fimbrial agglutinins in persons who have been infected with a salmonella or immunised with a TAB vaccine containing fimbrial antigens may lead to false-positive reactions being obtained in Widal tests.
TL;DR: A bacterium isolated in the laboratory, Arthrobacter paraffineus KY 4303, when grown on n-paraffin as the sole source of carbon, produced anthrone-positive lipid in the emulsion layer of the culture medium, identified as α-branched-β-hydroxy fatty acid trehalose ester.
Abstract: A bacterium isolated in our laboratory, Arthrobacter paraffineus KY 4303. when grown on n-paraffin as the sole source of carbon, produced anthrone-positive lipid in the emulsion layer (holding bacterial cells, lipids and n-paraffin remained) of the culture medium. This was isolated and identified as α-branched-β-hydroxy fatty acid trehalose ester.The addition of penicillin to the growing culture caused a significant suppression of trehalose lipid formation and led consequently to the accumulation of both the precursors, α, α-trehalose and α-branched-β-hydroxy fatty acid, in the culture medium.The formation of trehalose lipid was also observed in other bacteria which can utilize n-paraffin as the sole source of carbon. In addition, a possible role of this trehalose lipid in the utilization of n-paraffin by these bacteria was discussed.
TL;DR: Compared to N. crassa, no evidence was obtained for more than one kind of dehydroquinase activity in any of the bacteria examined, and the gene-enzyme relationships existing in the early steps of aromatic biosynthesis in bacteria and fungi are discussed.
Abstract: Ultracentrifugation in sucrose density gradients was employed to estimate the molecular weights and to determine possible physical aggregation of the five enzymes catalyzing steps two to six in the prechorismic acid portion of the polyaromatic synthetic pathway in six species of bacteria: Escherichia coli, Salmonella typhimurium, Aerobacter aerogenes, Bacillus subtilis, Pseudomonas aeruginosa, and Streptomyces coelicolor. The five enzymes were not aggregated in extracts of any of the species examined, nor are the genes encoding these enzymes clustered in those bacterial species for which genetic evidence exists. (An initial examination of the blue-green alga Anabaena variabilis indicates nonaggregation in this species also.) This situation in bacteria is in marked contrast to that found in Neurospora crassa and other fungi in which the same five enzymes are associated as an aggregate encoded (at least in the case of N. crassa) by a cluster of five genes. In addition, also in contrast to N. crassa, no evidence was obtained for more than one kind of dehydroquinase activity in any of the bacteria examined. These comparative results are discussed in relation to the origin, evolution, and functional significance of the gene-enzyme relationships existing in the early steps of aromatic biosynthesis in bacteria and fungi.
TL;DR: Of 123 species of bacteria surveyed for L-asparaginase synthesis, Erwinia aroideae NRRL B-138 provided the highest yields.
Abstract: Of 123 species of bacteria surveyed for L-asparaginase synthesis, Erwinia aroideae NRRL B-138 provided the highest yields.
TL;DR: Iron compounds greatly enhance the virulence of Escherichia coli for guinea-pigs, the lethal dose being reduced by approximately 100,000-fold, and the animals dying from an overwhelming infection with doses of bacteria that are normally harmless.
Abstract: IRON is essential for bacterial growth1, and there is now sufficient evidence to suggest that the ability to acquire iron may be an essential feature of pathogenicity2–5. Conversely, the ability of the host to prevent the uptake of iron by bacteria may constitute an important means of defence against certain infections2–4. Iron compounds can greatly reduce host resistance. The protection normally provided against Clostridium welchii type A by specific antiserum is abolished by injection of iron immediately before infection4. Similar results were obtained with a highly virulent strain of Pasteurella septica where a variety of iron compounds completely abolished the protective power of specific antiserum6. In both cases the ability of antiserum to suppress bacterial growth was removed, with the result that bacterial growth in iron-treated animals given antiserum was identical to that seen in unimmunized controls4,6. Iron compounds greatly enhance the virulence of Escherichia coli for guinea-pigs, the lethal dose being reduced by approximately 100,000-fold. In this case the normal ability to suppress bacterial growth is lost, the animals dying from an overwhelming infection with doses of bacteria that are normally harmless3.
TL;DR: This chapter considers three main groups of bacteria that include (1) strict or obligate thermophiles, these organisms show optimal growth at 65°–70°, and do not grow below 40°–42°; (2) facultative thermophilia, which have a maximum temperature for growth between 50° and 65° and are capable of growth at room temperature; and (3) thermotolerant organisms, which has a maximum growth temperature of 45°–50° and also
Abstract: Publisher Summary This chapter emphasizes on thermophilic bacteria belonging to the genus Bacillus and to the bacteriophages, which attack these organisms. The chapter considers three main groups of bacteria that include (1) strict or obligate thermophiles, these organisms show optimal growth at 65°–70°, and do not grow below 40°–42°; (2) facultative thermophiles, which have a maximum temperature for growth between 50° and 65°, and are capable of growth at room temperature; and (3) thermotolerant organisms, which have a maximum growth temperature of 45°–50° and also grow at room temperature. Thermophiles are isolated from soils of both temperate and tropical regions, air, salt, fresh water, from foods and grain, raw, pasteurized milk, and in faeces of man and domestic animals. As the incubation temperature for a thermophile is increased, there is an increase in the growth requirements of the particular organism under study. A thermophilic phage isolated from sewage-polluted river water exhibited an optimum temperature for lytic activity of about 50°, and had the ability to lyse its host at 57°–58°. The thermostability of the phage largely depends on the suspending fluid. In phosphate buffer or distilled water, the heat resistance is found to be less than when the phage is in broth or gelatin solution.
TL;DR: Fifteen strains of bacteria capable of degrading rutin anaerobically were isolated from bovine rumen contents and identified by morphological and biochemical evidence as strains of Butyrivibrio sp....
Abstract: Fifteen strains of bacteria capable of degrading rutin anaerobically were isolated from bovine rumen contents and identified by morphological and biochemical evidence as strains of Butyrivibrio sp....
TL;DR: Two substances known to be potent trichomonacides were shown to inhibit obligate anaerobic bacteria in vitro but were essentially without effect at the doses tested against bacteria capable of growing aerobically in vivo.
Abstract: 1-(2-Nitro-1-imidazolyl)-3-methoxy-2-propanol (RO 7-0582) and 2-methyl-5-nitroimidazole-1-ethanol (Metronidazole), substances known to be potent trichomonacides, were shown to inhibit obligate anaerobic bacteria in vitro but were essentially without effect at the doses tested against bacteria capable of growing aerobically. A similar effect was noted in vivo in that both substances exhibited good chemotherapeutic activity against infections produced by three species of anaerobic protozoa but were essentially inactive at the doses tested against three species of aerobic protozoa.
TL;DR: It is proposed that leukocyte D-amino acid oxidase and myeloperoxidase constitute a biochemically specific system for the recognition and killing of certain microorganisms.
Abstract: D-Amino acid oxidase has been identified within the granule fraction of human neutrophilic leukocytes. Leukocyte homogenates and purified kidney D-amino acid oxidase can utilize either isolated D-amino acids or some species of bacteria as substrates for the generation of hydrogen peroxide. When linked to leukocyte myeloperoxidase in vitro, purified D-amino acid oxidase constitutes a system lethal for certain bacteria. It is proposed that leukocyte D-amino acid oxidase and myeloperoxidase constitute a biochemically specific system for the recognition and killing of certain microorganisms.
TL;DR: The chemical and morphological similarity between blue-green algae and these bacteria is discussed and fatty acids in the lipids of 19 marine and terrestrial nitrifying bacteria have been analyzed.
Abstract: Fatty acids in the lipids of 19 marine and terrestrial nitrifying bacteria have been analyzed. Ammonia-oxidizing bacteria have a very simple acid composition; palmitic and palmitoleic acid account for 96 to 100% of the total acids. The fatty acids of nitrite-oxidizing bacteria cover a wider range, from C14 to C19, but from two to four acids still account for more than 80% of the total acids. Branched iso- and anteiso-acids are present in traces only in 2 of the 19 bacteria. The chemical and morphological similarity between blue-green algae and these bacteria is discussed.
TL;DR: The most suitable carbon source for 5-keto-d-fructose fermentation by Gluconobacter suboxydans Strain 1 was confirmed to be d-sorbitol or l-sorbose using growing and resting cells.
Abstract: During the course of studies on the oxidative metabolism of d-sorbitol by acetic acid bacteria, it was found that d-sorbitol was almost quantitatively converted to 5-keto-d-fructose via l-sorbose by a certain strain of Gluconobacter suboxydans. In addition to 5-keto-d-fructose, three γ-pyrone compounds, kojic acid, 5-oxymaltol, and 3-oxykojic acid, 2-keto-l-gulonate, and several organic acids such as succinic, glycolic, and glyceric acids were confirmed in the culture filtrate of this bacterium. The most suitable carbon source for 5-ketofructose fermentation by Gluconobacter suboxydans Strain 1 was confirmed to be d-sorbitol or l-sorbose using growing and resting cells. d-Fructose had little effect on the formation of this dicarbonylhexose.The optimal pH for the formation from l-sorbose by intact cells was found to be at 4.2.The activity of the pentose phosphate cycle in the resting cells was calculated as 13~17 μatoms/hr/mg of dry cells by the use of the manometric techniques.There was no strain tested s...
TL;DR: There is a significant level of infectious drug resistance among the intestinal bacteria of the urban population, and r factors conferring resistance to chloramphenicol, streptomycin, and tetracycline are identified.
Abstract: Raw and treated sewage samples were examined for antibiotic-resistant, lactose-fermenting bacteria. Approximately 1% of the total lactose-fermenting bacteria were multiply resistant. Of these organisms, 50% were capable of transferring all or part of their resistance to a drug-sensitive recipient. Only 43% of those isolated on media containing a single antibiotic were capable of resistance transfer, whereas 57% of those recovered on multiple antibiotic plates transferred resistance. R factors conferring resistance to chloramphenicol, streptomycin, and tetracycline; streptomycin and tetracycline; and ampicillin, streptomycin, and tetracycline accounted for 22, 19, and 15%, respectively, of those identified. The data indicate a significant level of infectious drug resistance among the intestinal bacteria of the urban population.
TL;DR: The chapter discusses the procedures to purify the enzyme from E. coli, strain K12 with dialyzed enzyme solution diluted with an equal volume of buffer—to reduce the KC1 concentration to 50 mM—and applied to the DEAE-cellulose column.
Abstract: Publisher Summary The chapter discusses the procedures to purify the enzyme from E. coli, strain K12. For the growth of microorganisms, fifteen liters of medium containing 50 mM sodium acetate as carbon source are made up in a glass carboy and inoculated with 200 ml of an actively growing culture of bacteria, which has been grown in the same medium at 37°. After 18-24 hours of growth, when the cell density is 0.7-0.9 mg/ml, dry weight, the cells are harvested and washed with cold water. For the preparation of sonic extracts, the washed cells are suspended to a density of approximately 40 mg/ml, dry weight, in the following buffer: 20 mM Tris-HC1, 10 mM MgC1 2 , and 1 mM EDTA, pH 8.0. This suspension, in cooled batches is treated in sonic oscillator (Dawe Soniprobe) at 4 amp for 90 minute. The supernatant solution is added slowly 35.1 g of finely ground solid (NH 4 ) 2 SO 4 (55% saturation). The dialyzed enzyme solution is diluted with an equal volume of buffer—to reduce the KC1 concentration to 50 mM—and applied to the DEAE-cellulose column. The degree of purity of citrate synthase prepared in this way is examined by electrophoresis on acrylamide gels. The enzyme is located in a single band which represents 90% or more of the protein present.
TL;DR: The outteromost laver of the cell wall of all marine ammonia-oxidizing bacteria so far isolated is made up of protein subunits arranged in a regular manner and linked together through metal-oxygen bonds.
Abstract: The outteromost laver of the cell wall of all marine ammonia-oxidizing bacteria So far isolated is made up of protein subunits arranged in a regular manner and linked together through metal-oxygen bonds. This sculptured, outer wall layver appears to be uniique to the terrestrial ammonia-oxidizing bacteria.
TL;DR: The fact that radioactivity is incorporated into the first three compounds suggests that in these organisms, and indeed in all those Gram-negative bacteria that contain 2-polyprenylphenols and 6-methoxy-2- polyprenyphenols, ubiquinones are formed by a biosynthetic sequence similar to that in Rhodospirillum rubrum.
Abstract: 1. Twenty-two aerobically grown Gram-negative bacteria were analysed for demethylmenaquinones, menaquinones, 2-polyprenylphenols, 6-methoxy-2-polyprenylphenols and ubiquinones. 2. All the eight enterobacteria and both the two facultative organisms (Aeromonas punctata and Aeromonas hydrophila) examined contain all the compounds listed above. The principal homologues are octaprenyl; in addition lower (down to tri- or tetra-prenyl for the 2-polyprenylphenols) and sometimes higher homologues are also present. 3. Strict aerobes are of two types, those that contain 2-polyprenylphenols, 6-methoxy-2-polyprenylphenols and ubiquinones, and those that contain ubiquinones only. The principal homologues are generally octa- or nona-prenyl, although one organism (Agrobacterium tumefaciens) has ubiquinone-10 as its principal homologue. As in the enterobacteria, lower homologues of these compounds are also present. 4. In Escherichia coli W, Pseudomonas ovalis Chester and Pseudomonas fluorescens, radioactivity from p-hydroxy[U-14C]benzoic acid is incorporated into 2-polyprenylphenols, 6-methoxy-2-polyprenylphenols, 6-methoxy-3-methyl-2-polyprenyl-1,4-benzoquinones, ubiquinones and a compound tentatively identified as 2-polyprenyl-1,4-benzoquinone. The fact that radioactivity is incorporated into the first three compounds suggests that in these organisms, and indeed in all those Gram-negative bacteria that contain 2-polyprenylphenols and 6-methoxy-2-polyprenylphenols, ubiquinones are formed by a biosynthetic sequence similar to that in Rhodospirillum rubrum. 5. The finding in `Vibrio O1' (Moraxella sp.) and organism PC4 that 2-polyprenylphenols and 6-methoxy-2-polyprenylphenols are chemically and radiochemically undetectable leads to the conclusion that they are not intermediates in the biosynthesis of ubiquinone by these and by other Gram-negative bacteria that do not contain detectable amounts of 2-polyprenylphenols and 6-methoxy-2-polyprenylphenols. However, `Vibrio O1' (organism PC4 was not examined) does contain 6-methoxy-3-methyl-2-polyprenyl-1,4-benzoquinone. 6. In Ps. ovalis Chester, radioactivity from l-[Me-14C]methionine is incorporated into the nuclear C-methyl and O-methyl groups of 6-methoxy-3-methyl-2-polyprenyl-1,4-benzoquinones and ubiquinone-9, and into the O-methyl group of 6-methoxy-2-polyprenylphenols.
TL;DR: Th Thin sections of methane-utilizing bacteria have been examined in the electron microscope and the fine structure of the cells is described for the first time, revealing the existence of intracellular membrane structures resembling those seen in nitrifying and photosynthetic bacteria.
Abstract: Summary.
Thin sections of methane-utilizing bacteria have been examined in the electron microscope and the fine structure of the cells is described for the first time. The outstanding feature of all the isolates studied is the existence of intracellular membrane structures resembling those seen in nitrifying and photosynthetic bacteria. The possible significance of these membranes is discussed.