Documents of antibiotic assays.
A new technique is described, in which a copy machine (Rank-Xerox) is used for instantaneous reproduction of biological assays.
Anti-Bacterial Agents↗
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Streptomyces torulosus sp. n., an unusual knobby-spored taxon.
Several strains of a streptomycete with unusual spore wall ornamentation were isolated from Iowa soils. They are further characterized by coiled chains of spores, gray aerial mycelium, melanin-like pigments, and the production of antibacterial and antifungal antibiotics. Spore wall ornamentations, as seen with the transmission electron microscope, do not correspond with any of the four generally recognized categories of spore wall ornamentation-smooth, warty, spiny, or hairy-but seem to represent an intermediate position between warty and spiny. This unusual ornamentation consists of blunt projections rising out of an otherwise smooth surface and is termed "knobby." To obtain further information on the nature of the knoblike projections and their possible status in representing a defined spore wall ornamentation category, scanning electron micrographs and transmission electron micrographs representing all sporewall ornamentation categories were compared. Differentiation between the several categories was more difficult with the scanning electron microscope than with the transmission electron microscope.
Anti-Bacterial Agents↗
Therapy of staphylococcal infections in monkeys. VII. Comparison of cyclacillin and nafcillin.
Intravenous inoculation of a penicillin-resistant phage type 80/81 staphylococcus caused lethal infection in seven of eight untreated monkeys. Daily intragastric administration of 50 mg/kg given in two equal morning and afternoon doses of cyclacillin and nafcillin was followed by mortalities of four of four and two of four monkeys, respectively. After 100 mg per kg per day, three of four and one of four monkeys receiving cyclacillin and nafcillin, respectively, died. Thus, mortality in controls and cyclacillin-treated monkeys was seven of eight as compared to three of eight after nafcillin treatment. Although the staphylococcus was more resistant to cyclacillin (minimal inhibitory concentration = 7.80 mug/ml) than to nafcillin (minimal inhibitory concentration = 0.31 mug/ml), regular rapid absorption and high levels of the former suggested potential efficacy. However, the similar mortality in cyclacillin-treated and control monkeys indicated that the in vitro data did not, in this instance, conform to the in vivo observations.
Animals↗
Microbiological study of a hypersaline lake in French Somaliland.
In a study of a lake having a higher concentration of salts than the Dead Sea, all of the heterotrophic bacteria isolated were aerobes; no strictly anaerobic strains were found. Ninety percent of the strains were euryhalines and ten percent were strict halophiles. The extreme halophiles belonged to the species Halobacterium trapanicum and Halococcus morrhuae.
Aerobiosis↗
Rapid method for the radioisotopic analysis of gaseous end products of anaerobic metabolism.
A gas chromatographic procedure for the simultaneous analysis of (14)C-labeled and unlabeled metabolic gases from microbial methanogenic systems is described. H(2), CH(4), and CO(2) were separated within 2.5 min on a Carbosieve B column and were detected by thermal conductivity. Detector effluents were channeled into a gas proportional counter for measurement of radioactivity. This method was more rapid, sensitive, and convenient than gas chromatography-liquid scintillation techniques. The gas chromatography-gas proportional counting procedure was used to characterize the microbial decomposition of organic matter in anaerobic lake sediments and to monitor (14)CH(4) formation from H(2) and (14)CO(2) by Methanosarcina barkeri.
Anaerobiosis↗
Inhibition of microbial growth by fatty amine catalysts from polyurethane foam test tube plugs.
When polyurethane foam test tube plugs are autoclaved, they release volatile fatty amines that inhibit the growth of some microorganisms. The chemical structures of these amines were determined by the use of a gas chromatograph-mass spectrometer. They are catalysts used to produce the foam. The problem of contaminating growth media with toxic substances released from polymeric materials is discussed.
Acinetobacter↗
Comparative ultrastructure of selected aerobic spore-forming bacteria: a freeze-etching study.
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Bacillus↗
Requirement for coenzyme A in the phosphoroclastic reaction of anaerobic bacteria.
Various bacteria which degrade pyruvate by the phosphoroclastic reaction were examined with respect to the role of coenzyme A (CoA) in this reaction. The strictly anaerobic bacteria, which cleave pyruvate by the phosphoroclastic reaction characteristic of Clostridia, required catalytic levels of CoA for the CO(2)-pyruvate exchange and acetoin-forming portions of the phosphoroclastic reaction. These reactions were reversibly inhibited by the CoA analogue, desulfo-CoA. In contrast, using cell-free extracts of bacteria which degrade pyruvate by the coliform phosphoroclastic reaction (pyruvate formate-lyase), no requirement for CoA could be observed for the formate-pyruvate exchange reaction. It is suggested that CoA serves a regulatory function in the early portion of the clostridal type of phosphoroclastic reaction.
Air↗
Comparative allostery of 3-deoxy-D-arabino-heptulosonate-7-phosphate synthetase as a molecular basis for classification.
The allosteric pattern of control for 3-deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthetase has previously been shown to be strongly conserved among the member species of a given genus in bacteria. The implications of this finding as a procedural tool of bacterial phylogeny were pursued by a study of two organisms, Sporosarcina ureae and Aeromonas formicans, the taxonomic positions of which have been historically controversial. S. ureae has characteristics of both Bacillaceae and Micrococcaceae, and A. formicans has characteristics of both Enterobacteriaceae and pseudomonads. Since the patterns of control for DAHP synthetase in all four of these microbial groups are different from one another but internally homogeneous within each group, the results obtained from the two test organisms were unambiguous. It was concluded that S. ureae is properly classified within Bacillaceae, probably deserving generic rank, and that A. formicans belongs with the family Enterobacteriaceae.
Aeromonas↗
Microbial transformation of antibiotics: phosphorylation of clindamycin by Streptomyces coelicolor Müller.
Addition of clindamycin to whole-cell cultures of Streptomyces coelicolor Müller resulted in the loss of in vitro activity against organisms sensitive to clindamycin. Incubation of such culture filtrates with alkaline phosphatase generated a biologically active material identified as clindamycin. Fermentation broths containing inactivated clindamycin yielded clindamycin 3-phosphate, the structure of which was established by physical-chemical and enzymatic studies. Clindamycin was phosphorylated by lysates and partially purified enzyme preparations from S. coelicolor Müller. These reactions require a ribonucleoside triphosphate and Mg(2+). The product of the cell-free reactions was identified as clindamycin 3-phosphate.
Adenosine Triphosphate↗
Effect of viscosity on bacterial motility.
The behavior of a number of motile flagellated bacteria toward viscosity characteristics of their fluid environments was observed. All showed an increase in velocity (micrometers per second) in more viscous solutions. Velocity reached a maximum at a characteristic value, however, and thereafter decreased with higher viscosities. Peritrichously flagellated bacteria had maximum velocities at higher viscosities than polarly flagellated bacteria. Effects of temperature, and possible utilization of chemical constituents in the viscous solutions, were studied and found to be negligible factors under the experimental conditions used. Different agents produced the same phenomenon, thus indicating that there probably were no chemically induced metabolic effects. Loss of available water and the possibility of a variable energy supply to the flagellar propulsive system were considered but are believed minimal. Theoretically derived thermodynamic equations were utilized and suggest that the conformation of the flagellar helix affects efficiency of propulsion. Such a relationship between helix waveform and velocity was experimentally observed with Thiospirillum jenese.
Bacillus megaterium↗
A correlation between the structure of neomycin B and its action on bacteria.
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Bacteria↗
Modification of radiation damage of bacteria by folic acid antagonists.
Pittillo, Robert F. (Southern Research Institute, Birmingham, Ala.), Mary Lucas, Robert T. Blackwell, and Carolyn Woolley. Modification of radiation damage of bacteria by folic acid antagonists. J. Bacteriol. 90:1548-1551. 1965.-The folic acid analogues, 2,4-diamino-6-methylpteridine, amethopterin, and aminopterin, have been found to sensitize certain bacteria, especially Escherichia coli, to the lethal action of ionizing irradiation. Data are presented which indicate that (i) the compounds must be present during the irradiation period for maximal sensitization to be observed, (ii) the sensitizing effect can be nullified by cysteine or cysteamine, (iii) the sensitizing effect occurs in a number of diverse bacterial genera, and (iv) folic acid neither sensitizes bacteria to irradiation nor prevents the sensitization caused by these antifolic agents.
Aminopterin↗
Ultrastructure of nonphotosynthetic carotenoid-containing bacteria.
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Carotenoids↗
Carotenoid pigments and photokilling by acridine orange.
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Acridines↗
Taxonomy of psychrophilic strains of Bacillus.
The morphological and physiological characteristics of 20 isolates of psychrophilic Bacillus were compared with 29 strains representing nine species of mesophilic Bacillus and 2 strains of Sporosarcina ureae to determine the taxonomic position of the psychrophiles. The psychrophiles formed four distinct groups which were sufficiently different from the mesophiles to warrant their designation as new species of Bacillus. The names B. psychrosaccharolyticus, B. insolitus, B. globisporus, and B. psychrophilus are proposed for the new species.
Bacillus↗
Ribosyl and deoxyribosyl transfer by bacterial enzyme systems.
The enzymatic transfer of ribose and deoxyribose residues in pyrimidine nucleosides to purines was catalyzed by cell-free extracts of various bacteria. Almost all the strains belonging to Enterobacteriaceae were capable of catalyzing the transfer reactions. The transfer activities were also detected among some bacterial strains of other families: Pseudomonadaceae, Corynebacteriaceae, Micrococcaceae, Bacteriaceae, and Bacillaceae. The rates of the transfer reactions were greatly enhanced in the presence of phosphate ion, and the participation of nucleoside phosphorylases in the reactions was suggested. Uridine phosphorylase, thymidine phosphorylase, and purine nucleoside phosphorylase were purified from cell-free extract of Aerobacter aerogenes IFO 3321. The ribosyl transfer from uridine to hypoxanthine was found to be catalyzed by the coupled reactions of uridine and purine nucleoside phosphorylases and the deoxyribosyl transfer from thymidine to hypoxanthine by the coupled reactions of thymidine and purine nucleoside phosphorylases.
Aeromonas↗
Actinomycin analogues containing pipecolic acid: relationship of structure to biological activity.
Streptomyces antibioticus synthesizes a mixture of actinomycins which differ at the "imino acid" site of the peptide chains. In the presence of exogenous pipecolic acid, several new actinomycins were synthesized and 70% of the proline in the antibiotic mixture was replaced by the analogue. Three new antibiotics (designated Pip 1alpha, Pip 1beta, and Pip 2) were isolated from culture filtrates, purified, and crystallized. The molar ratio of pipecolic acid to proline was: Pip 1alpha, 1:0; Pip 1beta, 1:1; Pip 2, 2:0. These compounds inhibited the growth and cell division of gram-positive, but not gram-negative, bacteria. The relative inhibitory activity against bacteria, Escherichia coli deoxyribonucleic acid (DNA)-dependent ribonucleic acid (RNA) polymerase in vitro, and RNA synthesis in Bacillus subtilis and mouse L-929 cells was: actinomycin IV = Pip 1beta > Pip 2 > Pip 1alpha. Protein synthesis in B. subtilis was less affected, and DNA synthesis was inhibited only at higher concentrations of antibiotic tested. In L cells, DNA formation was reduced less than RNA synthesis, whereas protein synthesis was not blocked under the experimental conditions employed. Kinetic studies with B. subtilis revealed that RNA synthesis was inhibited rapidly followed by an inhibition of protein synthesis. All four antibiotics markedly inhibited the replication of vaccinia virus and reovirus in tissue culture cells, but the production of poliovirus was resistant to the antibiotics. These actinomycins bind to DNA, resulting in an elevation of its T(m) and a decrease in the peak extinction of the actinomycins. The mode of action, as well as the structure-activity relationships among the actinomycins, are discussed relative to a previously proposed model of binding.
Bacillus subtilis↗