A new streptomycete and a new polyene antibiotic,acmycin

A new antifungal antibiotic named acmycin was isolated from a soil streptomycete. Detailed comparative taxonomic studies showed that the organism differed from three related species of streptomycetes. The organism was referred to asStreptomyces sp. AC₂. The isolated antibiotic appears to be of polyene nature.     

Degradation of organic nitrogenous wastes by a soil streptomycete

A soil streptomycete degraded hair, silk, wool, feather and leather which were collected from solid wastes. The organism was identified taxonomically and designated Streptomyces sp. A956. It degraded leather to the maximum extent and solubilized 35.9% of the total nitrogen, 2.32 mg of glycine equivalent amino nitrogen could be obtained by degradation of 100 mg leather.     

Streptomyces yatensis sp. nov., a novel bioactive streptomycete isolated from a New-Caledonian ultramafic soil

The taxonomic position of an actinomycete isolated from an ultramafic soil in New Caledonia was examined using a polyphasic approach. The organism, which was designated SFOCin 76, was found to have chemical and morphological properties typical of streptomycetes and formed a distinct phyletic line in the Streptomyces violaceusniger clade of the 16S rDNA tree. It also showed a unique pattern of phenotypic properties that distinguished it from representatives of all of the validly described species classified in this clade. It is, therefore, proposed that strain SFOCin 76 be classified in the genus Streptomyces as Streptomyces yatensis sp. nov. This revised version was published online in June 2006 with corrections to the Cover Date.     

Studies on a new marine streptomycete BT-408 producing polyketide antibiotic SBR-22 effective against methicillin resistant Staphylococcus aureus

A new actinomycete strain designated as BT-408 producing polyketide antibiotic SBR-22 and showing antibacterial activity against methicillin resistant Staphylococcus aureus has been characterized and found to be a novel strain of Streptomyces psammoticus. Nutritional and cultural conditions for the production of antibiotic by this organism under shake-flask conditions have been optimized. Glucose and ammonium nitrate were found to be best carbon and nitrogen sources respectively for growth and antibiotic production. Similarly initial medium pH of 7.2, incubation temperature of 30 degrees C and incubation time of 96 h were found to be optimal. Optimization of medium and cultural conditions resulted in 1.82-fold increase in antibiotic yield.     

A keratin-decomposing streptomycete

A proteolytic actinomycete was isolated from an Indian soil sample. It degraded hair, silk, wool and feather. Protease activity was reported for growth of the organism on these keratin substrates. The organism was taxonomically studied and designated as Streptomyces sp. S₇.     

Uncultured soil bacteria are a reservoir of new antibiotic resistance genes

Antibiotic resistance genes are typically isolated by cloning from cultured bacteria or by polymerase chain reaction (PCR) amplification from environmental samples. These methods do not access the potential reservoir of undiscovered antibiotic resistance genes harboured by soil bacteria because most soil bacteria are not cultured readily, and PCR detection of antibiotic resistance genes depends on primers that are based on known genes. To explore this reservoir, we isolated DNA directly from soil samples, cloned the DNA and selected for clones that expressed antibiotic resistance in Escherichia coli. We constructed four libraries that collectively contain 4.1 gigabases of cloned soil DNA. From these and two previously reported libraries, we identified nine clones expressing resistance to aminoglycoside antibiotics and one expressing tetracycline resistance. Based on the predicted amino acid sequences of the resistance genes, the resistance mechanisms include efflux of tetracycline and inactivation of aminoglycoside antibiotics by phosphorylation and acetylation. With one exception, all the sequences are considerably different from previously reported sequences. The results indicate that soil bacteria are a reservoir of antibiotic resistance genes with greater genetic diversity than previously accounted for, and that the diversity can be surveyed by a culture-independent method.     

Collagenase of a new streptomycete: Its induction and purification

Rifampin and chloramphenicol inhibited the synthesis of collagenase of Streptomyces sp. A₈, suggesting de novo synthesis. The collagenase was induced by insoluble collagen, its macromolecular fragments, gelatin, peptone, hide powder and yeast extract. Growth as well as collagenase synthesis were dependent on substrate availability. Purification of collagenase by DEAE-cellulose chromatography resulted in approximately 25-fold increase in activity (268.6 μmol glycine equivalents min^?1 mg^?1 protein) relative to the activity of the culture filtrate (10.5 μmol glycine equivalents min^?1 mg^?1 protein).     

A new species ofScopulariopsis from soil

A new species ofScopularoipsis described from soil is characterized by the conidiophores, branches, and sporogenous cells being distinctly swollen. The conidia have a well-marked germ slit running more or less longitudinally down the spore. TheScopulariopsis state ofMicroascus doguetii is re-examined and evidence is presented which indicates that the striations on the walls of the spores are germ slits.     

A new species ofConiochaetidium from soil

A new species ofConiochaetidium isolated from soil of Iraq is described. The speciesC. nuciforme differs fromC. savoryi in the shape and size of the ascospores. A key to differentiate the accepted species of the genus is reported.     

Activity of North Jordan soil streptomycete isolates against Candida albicans

Eighteen percent of 116 different isolates of Streptomyces recovered from soils of northern Jordan showed activity against Candida albicans. The recovered isolates were distributed into three groups according to the diameter of the inhibition zone on the agar plate: group 1 (5–10 mm, slightly active); group 2 (11–15 mm, moderately active); and group 3 (16–35 mm, highly active). Isolates of group 3 were further grouped into four sub-groups and were culturally and morphologically identified. The u.v. spectra of the fermentation broth for the isolates in sub-group 4 were determined, and showed absorbance peaks ranging between 230 and 300 nm.     

Coprinol, a new antibiotic cuparane from a Coprinus species

Coprinol, a new antibacterial cuparane, was isolated from fermentations of a Coprinus sp. Its biological activities were investigated and its structure was elucidated by spectroscopic methods. The new antibiotic exhibited activitiy against multidrug-resistant Gram-positive bacteria in vitro. Two derivatives were synthesized and their activities compared to the parent compound.     

The effects of temperature on growth and production of the antibiotic granaticin by a thermotolerant streptomycete

The synthesis of granaticin, a polyketide-derived antibiotic synthesized as a secondary metabolite by Streptomyces thermoviolaceus strain NCIB 10076, was studied at different growth temperatures. Quantitative measurements of the antibiotic made during batch fermentations showed that the yield was greatest at 45 degrees C, whereas the rate of synthesis was most rapid at 37 degrees C. The timing of the appearance of granaticin in culture could not be assigned to any particular phase of growth or to de-repression due to depletion of any particular nutrient. However, at all temperatures, appearance of the antibiotic coincided with a rise in ammoniacal nitrogen presumably due to deamination of glutamate, the carbon source for growth. We have previously shown that production of the antibiotic is pH sensitive and that some carbon sources result in higher titres than others. This paper examines the effect of temperature on the physiology of growth and on antibiotic production in more detail under conditions that also allow an exact measurement of granaticin yield.     

Mollisianitrile, a new antibiotic from Mollisia sp. A59-96

Mollisianitrile (1), a new antibiotic was isolated from the fermentation broth of Mollisa sp. A59-96 together with the two known isocoumarins 2 and 3. 1 exhibited antimicrobial, cytotoxic, and phytotoxic activities. 1 contains a reactive propiolonitrile moiety which is believed to be responsible for its antibiotic activities. Upon incubation with L-cysteine the biological activity was lost.