- Volume 132, Issue 7, 1986
Volume 132, Issue 7, 1986
- Physiology And Growth
-
-
-
Active Role of Oxygen and NADH Oxidase in Growth and Energy Metabolism of Leuconostoc
More LessSummary: Growth of 12 Leuconostoc strains in a broth medium with and without aeration was compared. In general, the aerated cultures grew faster and produced more biomass, at the expense of glucose and other sugars, than unaerated cultures. The more efficient growth correlated well with the production of acetate rather than ethanol as an end-product of metabolism in aerated cultures; unaerated cultures produced little or no acetate.
Mutants of L. mesenteroides X2 were isolated that had lost the capacity to be stimulated by aeration; they were completely deficient in NAD(P)H oxidase activity and did not accumulate acetate in aerobic cultures. Without NAD(P)H oxidase the mutants rely on the ethanol branch of the heterolactate pathway to regenerate NAD(P)+ from NAD(P)H, irrespective of the presence or absence of O2. The presence of NAD(P)H oxidase in parental cultures allows them to utilize O2 as a terminal electron acceptor and produce more ATP per mol of sugar utilized when O2 is available than when it is limiting.
-
-
-
-
Autotrophic Growth and Nitrogen Fixation in Derxia gummosa
More LessSummary: Initial attempts to grow N2-fixing Derxia gummosa autotrophically on H2, CO2, O2 and N2 in a closed system yielded variable results. Poor growth was found to be due to rapid O2 depletion and the requirement for an agar surface. In a closed system, C2H2 reduction assays could not be carried out due to complete consumption of H2. Hence a flow-through culturing technique was developed to supply gases at a constant partial pressure and to perform C2H2 reduction assays in a continuous flow system. Hydrogenase of autotrophic D. gummosa was not inhibited by C2H2, even at 0.5 atm, and the K m of hydrogenase for H2 was approximately 0.15 atm. The effects of O2 and H2 on C2H2 reduction were examined, using the flow-through assay system. The rate of C2H2 reduction decreased below 0.074 atm H2, suggesting that ATP and reductant supply were limiting the nitrogenase activity.
-
-
-
Glucose Regulation of Cephamycin Biosynthesis in Streptomyces lactamdurans is Exerted on the Formation of α-Aminoadipyl-cysteinyl-valine and Deacetoxycephalosporin C Synthase
More LessSummary: Glucose exerted a concentration-dependent negative regulation on the biosynthesis of cephamycin C by Streptomyces lactamdurans. Formation of the cephamycin precursor δ(α-aminoadipyl)-cysteinyl-valine was greatly decreased by excess glucose. The ring-expanding enzyme deacetoxycephalosporin C synthase was strongly repressed by glucose in vivo. Isopenicillin N synthase (cyclase) and isopenicillin N epimerase were not repressed by glucose. However, the activity of isopenicillin N synthase was inhibited in vitro by glucose 6-phosphate, and the activity of deacetoxycephalosporin C synthase was inhibited by inorganic phosphate, glucose 6-phosphate, fructose 2,6-diphosphate and fructose 1,6-diphosphate. The intracellular cAMP content decreased as growth proceeded and remained lower in glucose-supplemented cells than in control cultures. cAMP did not seem to be involved in glucose control of cephamycin biosynthesis.
-
-
-
Effect of Osmotic Stress on the Ultrastructure and Viability of the Yeast Saccharomyces cerevisiae
More LessSummary: Exposure of the yeast Saccharomyces cerevisiae to hypertonic solutions of non-permeating compounds resulted in cell shrinkage, without plasmolysis. The relationship between cell volume and osmolality was non-linear; between 1 and 4 OSM there was a plateau in cell volume, with apparently a resistance to further shrinkage; beyond 4 OSM cell volume was reduced further. The loss of viability of S. cerevisiae after hypertonic stress was directly related to the reduction in cell volume in the shrunken state. The plasma membrane is often considered to be the primary site of osmotic injury, but on resuspension from a hypertonic stress, which would have resulted in a major loss of viability, all cells were osmotically responsive. The effects of osmotic stress on mitochondrial activity and structure were investigated using the fluorescent probe rhodamine 123. The patterns of rhodamine staining were altered only after extreme stress and are assumed to be a pathological feature rather than a primary cause of injury. Changes in the ultrastructure of the cell envelope were examined by freeze-fracture and scanning electron microscopy. In shrunken cells the wall increased in thickness, the outer surface remained unaltered, whilst the cytoplasmic side buckled with irregular projections into the cytoplasm. On return to isotonic solutions these structural alterations were reversible, suggesting a considerable degree of plasticity of the wall. However, the rate of enzyme digestion of the wall may have been modified, indicating that changes in wall structure persist.
-
- Systematics
-
-
-
Enzyme-linked Immunosorbent Assay (ELISA) as a Means of Taxonomic Analysis of Streptomyces and Related Organisms
More LessSummary: Fourteen Streptomyces strains from various numerical taxonomic classes and representatives of three other genera of actinomycetes were studied using an indirect enzyme-linked immunosorbent assay (IND-ELISA) to determine their serological relationships. The IND-ELISA results agreed with those from previous numerical taxonomic analyses and Ouchterlony double-diffusion studies. The IND-ELISA method is quicker, more quantitative and less subjective than Ouchterlony assays and thus should be useful in Streptomyces taxonomy. The results indicated that Frankia sp. CpI1 was related to Streptomyces.
-
-
-
-
The Influence of Culture Age on the Cellular Fatty Acid Composition of Four Selected Yeasts
More LessSummary: Cellular fatty acids were extracted from cells of Debaryomyces vanrijiae, Saccharomycodes ludwigii, Endomyces fibuliger and Metchnikowia reukaufii at different growth stages of batch growth and analysed by gas chromatography. A high degree of variation in relative concentrations, as well as in composition, of fatty acids, was observed during the exponential and early stationary growth phases. Greater reproducibility and a relatively stable fatty acid composition were obtained with cells harvested in the late stationary phase.
-
-
-
Numerical Taxonomy of Red-pigmented Bacteria Isolated from a Lowland River, with the Description of a New Taxon, Rugamonas rubra gen. nov., sp. nov.
More LessSummary: Twenty red-pigmented bacterial strains, isolated from river water, and 15 named reference cultures were analysed using numerical taxonomic procedures. A simplified dendrogram, based on the simple matching coefficient and unweighted average linkage clustering algorithm, showed that the environmental isolates were recovered in two phenetic groups, defined at or above the 89% similarity level. Nine strains were contained in phenon 1, which exhibited the general characteristics of the Pseudomonadaceae, but did not match the descriptions of any of the existing genera within this family. A new genus and species, Rugamonas rubra, is proposed for these isolates. The 11 red-pigmented environmental strains in phenon 2 were identified as Serratia rubidaea. The red pigment of R. rubra contains at least two compounds related to prodigiosin. The major component produced a mass spectrum compatible with its being 6-methoxy-2-methyl-3-heptylprodigeosene (m/e 351). A second component produced a mass spectrum indistinguishable from that of prodigiosin itself (m/e 323).
-
-
-
Characterization of Corynebacterium Group JK by Whole-cell Protein Patterns
More LessSummary: A total of 102 strains received as Corynebacterium ‘group JK’ were characterized by SDS-PAGE of their whole-cell proteins. Numerical taxonomy based on the protein pattern absorbance profiles indicated that 91 of the strains formed a cluster. Seventy strains isolated in the UK were identified as group JK, indicating the increasing detection of this group as opportunistic pathogens. Fine differences between strain patterns were visible but it was not possible to associate these with any particular clinical source.
-
-
-
A Non-luminescent Strain of Xenorhabdus luminescens (Enterobacteriaceae)
More LessSummary: The first case of a non-luminescent symbiont of a Heterorhabditis sp. is reported. The bacterium, isolated from a previously unknown species of Heterorhabditis, was identified as a biovar of Xenorhabdus luminescens. Ultrastructural study of the bacterium revealed membranous and crystalline inclusions comparable with those of luminescent strains of X. luminescens
-
-
-
Mycoplasma felifaucium, a New Species Isolated from the Respiratory Tract of Pumas
More LessSummary: Mycoplasmas isolated from the throats of three pumas (Felis concolor) were each cloned and examined in detail. All three were serologically and biologically indistinguishable from each other, and were serologically distinct from 83 recognized Mycoplasma and Acholeplasma species. They were designated as a new species, Mycoplasma felifaucium, with strain PU (NCTC 11703) as the type strain.
-
-
-
Use of Penicillin-binding Proteins for the Identification of Enterococci
More LessSummary: The results of 20 physiological and fermentation tests and examination of the penicillin-binding proteins (PBPs) of 85 enterococcal strains demonstrated that the genus Enterococcus could be divided into at least nine distinct species: E. faecalis, E. faecium, E. durans, E.hirae, E.avium, E. gallinarum, E. casselifiavus, E. malodoratus and E. mundtii. Each species had a specific pattern of at least five PBPs, with molecular masses in the range of about 40–130 kDa. The pattern of PBPs may be useful for identification purposes, since some strains with unusual fermentation characteristics were assigned to species by this technique.
-
- Short Communication
-
-
-
Analysis of Surface Receptor Expression on Bacteria Isolated from Patients with Endocarditis
More LessSummary: Fifteen bacterial isolates (12 streptococcal and 3 staphylococcal strains) from patients with bacterial endocarditis were screened for a variety of surface receptors, in an attempt to identify a common feature that might contribute to their ability to attach to and colonize damaged heart tissue. The bacterial receptors screened for, using a dot-blot autoradiographic procedure, included those for the Fc region of human IgG, fibrinogen, fibronectin and human Clq. Bacteria with receptors for each of the probes used could be identified, but no common receptor was present on all endocarditis-causing strains.
-
-
-
-
Water Stress Plating Hypersensitivity of Yeasts
More LessSummary: Saccharomyces cerevisiae, when growing exponentially in batch culture, passed through a phase in which, on average, one cell in 104 survived plating onto a low water activity (a w) agar medium. Stationary phase cultures were resistant as were all other species tested, with the exception of Candida krusei. In continuous culture, S. cerevisiae was more resistant at low than at high dilution rates. Plating at low a w was lethal to those cells that were not protected by an adequate content of compatible solute. In naturally resistant yeasts and in S. cerevisiae that had been exposed to an adaptation process, the compatible solute was one or more types of polyhydric alcohol. Resistance in stationary phase was attributable to a different cause.
-
-
-
Modelling of Nutrient Gradients in a Bacterial Colony
More LessSummary: Oxygen and substrate gradients were simulated with a finite-volume method for a variety of bacterial colony sizes and substrate concentrations. A spherical segment geometry and a Monod relationship for simultaneous substrate and O2 consumption were assumed. The results agreed well with previous theoretical and experimental estimates for gradients in microbial colonies.
-
Volumes and issues
-
Volume 170 (2024)
-
Volume 169 (2023)
-
Volume 168 (2022)
-
Volume 167 (2021)
-
Volume 166 (2020)
-
Volume 165 (2019)
-
Volume 164 (2018)
-
Volume 163 (2017)
-
Volume 162 (2016)
-
Volume 161 (2015)
-
Volume 160 (2014)
-
Volume 159 (2013)
-
Volume 158 (2012)
-
Volume 157 (2011)
-
Volume 156 (2010)
-
Volume 155 (2009)
-
Volume 154 (2008)
-
Volume 153 (2007)
-
Volume 152 (2006)
-
Volume 151 (2005)
-
Volume 150 (2004)
-
Volume 149 (2003)
-
Volume 148 (2002)
-
Volume 147 (2001)
-
Volume 146 (2000)
-
Volume 145 (1999)
-
Volume 144 (1998)
-
Volume 143 (1997)
-
Volume 142 (1996)
-
Volume 141 (1995)
-
Volume 140 (1994)
-
Volume 139 (1993)
-
Volume 138 (1992)
-
Volume 137 (1991)
-
Volume 136 (1990)
-
Volume 135 (1989)
-
Volume 134 (1988)
-
Volume 133 (1987)
-
Volume 132 (1986)
-
Volume 131 (1985)
-
Volume 130 (1984)
-
Volume 129 (1983)
-
Volume 128 (1982)
-
Volume 127 (1981)
-
Volume 126 (1981)
-
Volume 125 (1981)
-
Volume 124 (1981)
-
Volume 123 (1981)
-
Volume 122 (1981)
-
Volume 121 (1980)
-
Volume 120 (1980)
-
Volume 119 (1980)
-
Volume 118 (1980)
-
Volume 117 (1980)
-
Volume 116 (1980)
-
Volume 115 (1979)
-
Volume 114 (1979)
-
Volume 113 (1979)
-
Volume 112 (1979)
-
Volume 111 (1979)
-
Volume 110 (1979)
-
Volume 109 (1978)
-
Volume 108 (1978)
-
Volume 107 (1978)
-
Volume 106 (1978)
-
Volume 105 (1978)
-
Volume 104 (1978)
-
Volume 103 (1977)
-
Volume 102 (1977)
-
Volume 101 (1977)
-
Volume 100 (1977)
-
Volume 99 (1977)
-
Volume 98 (1977)
-
Volume 97 (1976)
-
Volume 96 (1976)
-
Volume 95 (1976)
-
Volume 94 (1976)
-
Volume 93 (1976)
-
Volume 92 (1976)
-
Volume 91 (1975)
-
Volume 90 (1975)
-
Volume 89 (1975)
-
Volume 88 (1975)
-
Volume 87 (1975)
-
Volume 86 (1975)
-
Volume 85 (1974)
-
Volume 84 (1974)
-
Volume 83 (1974)
-
Volume 82 (1974)
-
Volume 81 (1974)
-
Volume 80 (1974)
-
Volume 79 (1973)
-
Volume 78 (1973)
-
Volume 77 (1973)
-
Volume 76 (1973)
-
Volume 75 (1973)
-
Volume 74 (1973)
-
Volume 73 (1972)
-
Volume 72 (1972)
-
Volume 71 (1972)
-
Volume 70 (1972)
-
Volume 69 (1971)
-
Volume 68 (1971)
-
Volume 67 (1971)
-
Volume 66 (1971)
-
Volume 65 (1971)
-
Volume 64 (1970)
-
Volume 63 (1970)
-
Volume 62 (1970)
-
Volume 61 (1970)
-
Volume 60 (1970)
-
Volume 59 (1969)
-
Volume 58 (1969)
-
Volume 57 (1969)
-
Volume 56 (1969)
-
Volume 55 (1969)
-
Volume 54 (1968)
-
Volume 53 (1968)
-
Volume 52 (1968)
-
Volume 51 (1968)
-
Volume 50 (1968)
-
Volume 49 (1967)
-
Volume 48 (1967)
-
Volume 47 (1967)
-
Volume 46 (1967)
-
Volume 45 (1966)
-
Volume 44 (1966)
-
Volume 43 (1966)
-
Volume 42 (1966)
-
Volume 41 (1965)
-
Volume 40 (1965)
-
Volume 39 (1965)
-
Volume 38 (1965)
-
Volume 37 (1964)
-
Volume 36 (1964)
-
Volume 35 (1964)
-
Volume 34 (1964)
-
Volume 33 (1963)
-
Volume 32 (1963)
-
Volume 31 (1963)
-
Volume 30 (1963)
-
Volume 29 (1962)
-
Volume 28 (1962)
-
Volume 27 (1962)
-
Volume 26 (1961)
-
Volume 25 (1961)
-
Volume 24 (1961)
-
Volume 23 (1960)
-
Volume 22 (1960)
-
Volume 21 (1959)
-
Volume 20 (1959)
-
Volume 19 (1958)
-
Volume 18 (1958)
-
Volume 17 (1957)
-
Volume 16 (1957)
-
Volume 15 (1956)
-
Volume 14 (1956)
-
Volume 13 (1955)
-
Volume 12 (1955)
-
Volume 11 (1954)
-
Volume 10 (1954)
-
Volume 9 (1953)
-
Volume 8 (1953)
-
Volume 7 (1952)
-
Volume 6 (1952)
-
Volume 5 (1951)
-
Volume 4 (1950)
-
Volume 3 (1949)
-
Volume 2 (1948)
-
Volume 1 (1947)