- Volume 44, Issue 3, 1966
Volume 44, Issue 3, 1966
- Article
-
-
-
Ecology of Micro-Organisms on Chitin Buried in Soil
More LessSUMMARY: The quantitative ecology of micro-organisms developing on pieces of chitin buried in soil was studied by systematically recording morphologicalgroups and subgroups of micro-organisms developing on them. A temperate and a tropical soil were used. Both soils were incubated at 10° and 29°, temperatures which might be expected in the respective climatic regions from which the soils were collected. In both soils the organisms most frequently observed at 10° were fungi and bacteria; at 29° actinomycetes,nematodes and protozoa werealso observed, besides fungi and bacteria.The main differences in the nature of organismsfrom both soils observed on chitin was in the subgroups rather than in the major groups.
-
-
-
-
Phosphomannans and Other Components of Flocculent and Non-Flocculent Walls of Saccharomyces cerevisiae
More LessSUMMARY: Preparations of flocculent and of non-flocculent cell walls were obtained from flocculent and non-flocculent cells of a strain of Saccharomyces cerevisiae. Flocculent walls contained 46% glucan, 43% mannan, 0.4% P, 1.1% hexosamine, 0.79% non-hexosamine N; non-flocculent walls contained 47% glucan, 44% mannan, 0.3% P, 1.2% hexosamine and 0.98%non-hexosamine N.
Mannose-6-phosphate was identified as the principal phosphorus compound present. The mannose residue formed part of the cell-wall mannan and the phosphate was also linked by a second, labile, ester bond to an unidentified site. The degree of phosphorylation of the mannan varied from 1 phosphate to 19 mannose residues in non-flocculent cells to 1 phosphate to 13 residues in flocculent cells.
-
-
-
The Antibacterial Action of Tetrachlorsalicylanilide
More LessSUMMARY: Tetrachlorsalicylanilide (TCS) is a skin germicide which is bacteriostatic for Gram-positive bacteria at low concentrations and bactericidal at high concentrations; both activities are dependent on inoculum size and are not specific to a particular growth phase. Glucose oxidation by Staphylococcus aureus was inhibited at TCS1 μg./ml. whereas 20 μg./ml. was required to inhibit glucose fermentation. S. aureus treated with TCS which released amino acids did not accumulate 14C-labelled 1-glutamic acid, 1-lysine, 1-aspartic acid or sodium succinate. Inhibition by TCS of these processes as well as bacteriostasis was annulled by subsequent treatment with normal horse serum.
-
-
-
Location of Tetrachlorsalicylanilide Taken up by Bacillus megaterium
More LessSUMMARY: 14C-Tetrachlorsalicylanilide (TCS) was taken up by Bacillus megaterium, becoming localized on the cytoplasmic membrane and was recoverable from the membrane by treatment with normal horse serum. Normal phase-dark B. megaterium protoplasts became phase-bright and distorted on addition of TCS; osmotically resistant ‘protoplasts’ in buffer were obtained from TCS-treated B. megaterium subsequently treated with lysozyme. Both these conditions were inhibited or annulled by serum.
-
-
-
The Morphology of Vesicular Stomatitis Virus (Indiana C) Derived from Chick Embryos or Cultures of BHK21/13 Cells
More LessSUMMARY: The virus of vesicular stomatitis is shown to exist as a system of several particle forms. Two major particles, the ‘bullet’ and ‘cap’, appear in electron micrographs in various states as outer structural layers are absent or lost. High infectivity is not associated with particles of one form. The distribution of particle forms is apparently determined by cultural conditions and is not significantly modified by the preparative procedures employed.
The morphology of the several components of the virus system is described.
-
-
-
Taxonomy of the Acidophilic Thiobacilli
More LessSUMMARY: Numerical analysis was applied to the taxonomy of acidophilic thiobacilli; 22 strains were examined, including authentic cultures and new isolates. Two sets of tests were made with different substrates, sulphur and thiosulphate. The results from both sets of tests indicated two distinct groups corresponding to Thiobacillus thio-oxidans and T. ferro-oxidans.
-
-
-
The Fluorescent Staining of Bacteriophage Nucleic Acids
More LessSUMMARY: The staining of viral nucleic acids with acridine orange and their subsequent examination under the fluorescence microscope permits the determination of the type and strandedness. Since the existing procedures are complicated, modifications have been devised which simplify them and avoid the use of the fluorescence microscope, an ordinary ultraviolet lamp being substituted. Also, it has been found that certain post-staining treatments cause colour changes which are related to the strandedness and type of nucleic acid and hence are valuable confirmations of the normally used nuclease sensitivity tests. The new procedures were tested for a wide range of specimens including double-stranded ribonucleic acid, but emphasis has been placed on the identification of bacteriophage nucleic acids.
-
-
-
The Oxidation of Fatty Acids by Spores of Penicillium roqueforti
More LessSUMMARY: The ability of washed spores of Penicillium roqueforti to oxidize fatty acids decreased markedly with age but was restored by adding specific sugars and amino acids. Only the C6 to C12 fatty acids were oxidized to the corresponding methyl ketone with one less carbon atom. The yield of methyl ketone between pH 5.5 and 7.0 decreased progressively from a maximum of 75% from octanoic acid to zero from myristic acid. The small amounts of metabolic carbon dioxide evolved greatly stimulated the oxidation of C10 and C12 fatty acids. The addition of sodium azide, 2,4-dinitrophenol (DNP) and certain divalent metallic ions, but not chloramphenicol, inhibited the oxidation of fatty acids. Oxidation was preceded by a lag period which was lengthened by increasing the fatty acid concentration or by decreasing the concentration of spores. Since cell-free extracts of spores were able to oxidize fatty acids, the lag phase with whole spores appears to be due to the absence of active transport systems. This is also indicated by the elimination of the lag phase by pre-incubation with octanoic acid but not by pre-incubation with glucose or casamino acids. The possible significance of methyl ketone formation in fatty acid metabolism is discussed.
-
-
-
A Study of Conidiation in Neurospora crassa
More LessSUMMARY: Two distinct forms of growth of wild-type Neurospora crassa can be produced by altering the nitrogen source of the growth medium. One form completely lacks conidia and carotenoids; the other exhibits enhanced conidiation and pigmentation. Analysis of the oxidative and glycolytic metabolism of these two forms showed that the non-conidiating cultures had significantly greater glycolytic activity than the conidiating cultures, as measured by the production of ethanol, the presence of ethanol dehydrogenase and pyruvate decarboxylase activity and the response of the two culture types to glycolytic inhibitors. When glycolysis was inhibited, conidiation occurred. When oxidative metabolism in normally conidiating cultures was interfered with conidiation was suppressed. These results suggest that the relative activities of fermentative and oxidative pathways in the cell regulate both conidiation and pigment synthesis. The most probable point at which this control is exercised is at the stage of pyruvate, the common branch point of these two pathways. Conidiating cultures also were found to have very high NADP nucleotidase activity, while purely mycelial cultures were essentially devoid of this enzyme. An electron microscope examination of these two culture types revealed differences in cell-wall composition, in the distribution of osmiophilic granules within the cytoplasm and in mitochondrial structure.
-
-
-
An Index to Deoxyribonucleic Acid Base Compositions of Bacterial Species
More LessSUMMARY: This paper consists of a reference list of bacterial species for which deoxyribonuclieic acid base compositions are known. Culture-collection strain numbers have been included wherever possible. The compilation may also provide a basis for the inclusion of these data into species descriptions.
-
-
-
The Amino Acid Utilization by Phase I Bordetella pertussis in a Chemically Defined Medium
More LessSUMMARY: Phase I Bordetella pertussis was grown in a chemically defined medium containing 20 amino acids (including glutamine) plus glutathione. Growth was limited by depletion of three of the components, L-glutamic acid, L-proline and L-glutamine. Increasing the concentrations of these three components more than doubled the yield of organism. The following components were utilized, but did not limit growth: alanine, glycine, histidine, serine; cystine and glutathione were also substantially used. Ten amino acids which were not utilized to any significant extent could be omitted without diminishing growth. A preferential order of amino acid utilization is suggested. Glutamic acid appears to be important for antigenicity.
-
-
-
The Amino Acid Use in Cultures of Phase I Bordetella pertussis During Growth in Chemically Defined Media
More LessSUMMARY: The primary metabolic importance of glutamic acid for phase I Bordetella pertussis was illustrated by its rapid use during the exponential stage of the growth in a chemically defined medium. The pattern of uptake of proline, in particular, and of glutamine resembled that of glutamic acid; this was explained in terms of the conversion of proline and glutamine to glutamic acid. Other substantially used amino acids (alanine, glycine, histidine, serine) were taken up when the readily available sources of glutamic acid became exhausted and the culture entered the stationary phase of growth. The results given show the order of uptake for the amino acids in relation to the growth stage of the culture. No relation was apparent between the amino acid uptake and the immunogenicity of the organisms throughout the growth period.
-
- Books Received
-
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)