- Volume 58, Issue 1, 1969
Volume 58, Issue 1, 1969
- Articles
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Studies on Stigmatella aurantiaca (Myxobacterales)
More LessSUMMARYWe have isolated the fruiting myxobacterium Stigmatella aurantiaca from wood and bark, and have examined some aspects of its ecology, morphology, physiology and taxonomy. Vegetative cells were Gram-negative, spindle-shaped rods 5·2 to 8·4 μ long and 0·65 to 0·74 μ wide. The myxospores were optically refractile short rods measuring about 3·2 × 1·0 μ. Fruiting bodies were usually bright orange or red brown and consisted of a stalk 60 to 140 μ high bearing 1 to 20 cysts at its top. Most cysts were spherical or ovoid, measuring 40 to 60 μ by 25 to 45 μ. S. aurantiaca was cultivated in liquid culture in a dispersed vegetative state or on solid media, producing either fruiting bodies or vegetative forms. Optimal vegetative growth was obtained with a medium containing Casitone, glucose and salts. The optimal temperature for growth was 30°. Cultures could be preserved by storage of vegetative forms at – 60° or of dried myxospores or fruiting bodies at – 18°. Dried myxospores were resistant to desiccation and elevated temperatures. We propose that Stigmatella, which had been incorporated into the genus Chondromyces, be re-established as a separate genus within the Polyangiaceae. We further propose the inclusion of Chondromyces among the Sorangiaceae.
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Thiamine Limited Steady State Growth of the Yeast Cryptococcus albidus
More LessSUMMARYThe concentration/growth rate relationship of thiamine-requiring Cryptococcus albidus was examined. Data suggest a diffusion-limited mechanism characterized by an apparent Michaelis constant for growth of 4·7 × 10–13 m. This relationship was obtained from continuous culture at steady state and tested by a non-steady state procedure and in batch growth. It was concluded that most natural water systems have sufficient thiamine to support some thiamine-requiring micro-organisms at above rate limiting concentrations.
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An Ultrastructural Study of the Hyphae, Endoconidia and Chlamydospores of Thielaviopsis basicola
More LessSUMMARYThe cell wall of hyphae of Thielaviopsis basicola consisted of an inner transparent layer and an outer electron-dense layer. The cell wall of the endoconidia was usually composed of a single transparent layer; at the tip of the endoconidia distal from the phialide the cell wall protruded into the cytoplasm. Hyphal tubes that contained endoconidia were devoid of cytoplasmic components. The only cytoplasmic component recognizable in the phialide was the endoplasmic reticulum. Two complex cell-wall systems were observed in chlamydospores. An outer cell wall enclosed the whole chlamydospore and each individual compartment possessed its own separate cell wall. Both cell walls were composed of an outer very electron-dense layer and an inner layer which appeared to be electron-transparent.
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The Supply of Cholesterol and Fatty Acids for the Growth of Mycoplasmas
More LessSUMMARYMycoplasma strain y, serologically and biochemically related to Mycoplasma mycoides, grew well in a medium containing unesterified fatty acids, cholesterol and some samples of fatty acid-poor bovine serum albumin. With other samples of serum albumin, growth was accompanied by cellular lysis. Heating albumin solutions, treating them with charcoal, or varying the ratio of fatty acids to albumin, the concentration of cholesterol, or the order in which the lipid components were added to the medium, all influenced the amount of lysis. These effects may be due to varying interaction between fatty acids and cholesterol and between fatty acids and albumin. When fatty acids are firmly bound to albumin, their interaction with cholesterol is prevented, resulting in a cholesterol deficiency. Lysis was prevented by the addition of a heat-stable defatted serum protein fraction (fraction C), or a pronase digest of fraction C, both of which dispersed cholesterol.
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A Defined Medium for Mycoplasma Strain Y
More LessSUMMARYIn a defined medium for Mycoplasma strain Y, a mixture of the diacetoxysuccinoyl esters of monoolein and monopalmitin replaced unesterified fatty acids and serum protein fractions, enabling the minimal growth requirements to be determined. Other Mycoplasma strains did not grow in media in which these esters replaced fatty acids and protein fractions.
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Sources of Carbon and Energy used by Coprinus lagopus sensu Buller
More LessSUMMARYThe sources of carbon + energy utilized by a strain of Coprinus lagopus which is in wide use in biochemical and genetic experiments have been determined. Over 120 compounds were tested for growth in liquid medium. Only acetate, fructose, glucose, maltose, mannitol, mannose, xylose and the polymers cellulose and starch supported growth as sole carbon + energy sources at 10 mm concentration. Amino acids were used as sources of carbon, but only in the presence of equimolar amounts of glucose. Suggestive evidence was obtained for inducible enzyme systems concerned with the utilization of ethanol, lactose and alginate.
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Host-controlled Restriction Mutants of Salmonella typhimurium
More LessSUMMARYForty-eight independent restriction-deficient mutations of Salmonella typhimurium lt 2 were isolated by using selective and non-selective methods. With phage P 22 it was shown that some mutations affected the restriction capacity only, while others affected both restriction and modification. The host-restriction of S. typhimurium decreased the recovery of F-lac + infected cells and decreased the yield of recombinants in bacterial mating and in phage P 22-mediated transduction.
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Transduction of pro + to Salmonella typhimurium proAB47 by Phage P22
More LessSUMMARYThe multisite mutant Salmonella typhimurium proAB 47 was infected with phage P 22 from a suspension mediating restricted transduction of proline markers. Evidence was obtained which supports the conclusion that proAB 47 forms only a few colonies by the mechanism of restricted transduction, and that the near absence of this class of transductants is responsible for the low frequency of incorporation of the pro + marker by this strain.
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Transformation of Phage-sensitivity in Bacillus subtilis
More LessSUMMARYTwo methods were developed to demonstrate a small fraction (10–4) of phage-sensitive cells in a phage-resistant population with a high degree of accuracy, using the plexiglass phage titration method (Horváth & Alföldi, 1954).
Phage-sensitivity was transferable by DNA isolated from Bacillus subtilis 168 m trp + phs (SPO-1 phage-sensitive) to the recipient strain of 168 m trp phr (SPO-1 phage-resistant) in transformation experiments. The number of 168 m trp + phs transformants was a function of the concentration of the transforming DNA. The trp + and phs characters are not linked. The competence curves for the number of 168 m trp + phr and 168 m trp + phs transformants were similar. The phenotypic lag was found to be 5 hr 30 min. The maximum frequency of 168 m trp + phs cells among the transformants was 2 to 5 %.
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The Partial Purification and Properties of Endopolygalacturonase and α-l-Arabinofuranosidase secreted by Sclerotinia fructigena
More LessSUMMARYAn endopolygalacturonase (PG) and an α-l-arabinofuranosidase (AF) in culture filtrates of the fungus Sclerotinia fructigena were partially purified by ion-exchange chromatography on CM-Sephadex and Ecteola-cellulose columns, and characterized. Molecular weight estimations by gel-filtration and electrophoresis on cellulose acetate strips indicated that both enzymes existed in multiple forms. The PG showed unusual stability to extreme pH values, to classical inhibitors, and to proteolytic enzymes; in the crude filtrate a bimodal temperature/stability curve was obtained.
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Lactic Dehydrogenases of Strains of the Genus Leuconostoc
More LessSUMMARYThe lactic dehydrogenases of 11 strains of the genus Leuconostoc were examined. All possessed a d(–) but no l(+) NAD-dependent lactic dehydro-genase, and three strains (1 L. mesenteroides and 2 L. paramesenteroides) also had d(–) and l(+) NAD-independent lactic dehydrogenases. The NAD-dependent enzyme of the seven strains belonging to the species L. mesenteroides, L. dextranicum, L. paramesenteroides, L. lactis and L. cremoris moved together during electrophoresis in acrylamide gel. The enzymes of the other four strains, all L. oenos, were close together but widely separated from the enzyme of the other species. One strain of L. mesenteroides oxidized NADH without added pyruvate. The enzyme responsible was located after electro-phoresis.
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The Serological Identity of Sabin’s Murine type C Mycoplasma and Mycoplasma pulmonis
More LessSUMMARYSerological evidence is presented that Sabin’s murine type C mycoplasma belongs to the species Mycoplasma pulmonis and not to a separate species, M. histotropicum.
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Bacteriological and Serological Studies of Fast Growing Mycobacteria Identified as Mycobacterium friedmannii
More LessSUMMARYThree recently isolated strains of a fast growing non-pigmented mycobacterium, two of which were from a series of injection abscesses and one which was recovered from a water tank, have been compared bacteriologically and serologically in gel-diffusion tests with a number of mycobacterial type strains. The three strains and type strains of M. abscessus, M. runyonii, M. borstelense and M. friedmannii were of one species. This species differed in several respects from M. ranae (fortuitum), M. smegmatis and M. thamnopheos. In view of the chronological priority of M. friedmannii over the other names, we recommend that this name be adopted as the correct designation for this species. The origin of the type strain of M. friedmannii is discussed and reasons are given for its acceptance as representative of Friedmann’s original strains.
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Stable Coexistence of Three Resistance Factors (fi –) in Salmonella panama and Escherichia coli k 12
More LessSUMMARYDuring an epidemic, a strain of Salmonella panama resistant to ampicillin, kanamycin, tetracycline and which was colicinogenic was isolated. The three drug-resistance determinants were transferred singly, in pairs or en bloc to sensitive Escherichia coli k 12 strains. When the recipient was an Hfr strain, it remained sensitive to F-specific phage f 2, so the transferred resistance factors can be classified as fi –. The three resistance characters were always independently transduced by phage P 1-b, and remained transferable in subsequent conjugations. In contrast to closely related R factors or Col factors which cannot coexist stably in the same cell, the three R factors described here do not specifically interfere with one another. They are maintained together in the naturally occurring strain of S. panama and after successive transfer to E. coli k 12. These results support the hypothesis that three independent fi – resistance factors, R (Am), R (Km), R (Tc) and a Col factor coexist in S. panama and E. coli k 12 strains.
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Correlation of Bacterial Sensitivities to Ionizing Radiation and Mild Heating
More LessSUMMARYDNA, isolated from bacteria which had been heated to 52° 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 52° 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.
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Linear Growth Kinetics of Plaque-forming Streptococci in the Presence of Sucrose
More LessSUMMARYGrowth of intact plaques of dextran-forming strain sl-1 was linear both on a dry weight and DNA basis. Growth of broth cultures of dextran-forming strains sl-1 and e-49 was linear with sucrose but exponential with other sugars; non dextran-forming strains 4m4 and jr8lg grew exponentially with all sugars tested. When dextranase was added to slowly growing cultures of dextran-forming strains sl-1 and e-49, growth became rapid. Linear growth of strains sl-1 and e-49 with sucrose is ascribable to extracellular dextran synthesized by the organisms.
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The Problem of the Similarity of Objects in Numerical Taxonomy
R. JIčÍN and Z. VAŠÍČEKSUMMARYThe existing definitions of coefficients of association in numerical taxonomy are not sufficiently well based theoretically. The present paper aims to make more objective the definition of the coefficient of association. It proceeds from the fact that the main source of difficulty is the third value (NC) used in scoring characters, and eliminates it. An improved coefficient of association between objects is then defined as the mean value of the coefficients of association of the individual pairs of forms of objects that are constructed by the method proposed below.
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