Effect of various carbon and nitrogen sources on the biosynthesis of ristomycin, protease and pigments by a culture of Nocardia fructiferi var. ristomycini

The effect of various sources of carbon and nitrogen on the biosynthesis of ristomycin, protease and pigments by Nocardia fructiferi was studied. It was shown that the carbon sources had the most significant effect on the biosynthesis of the antibiotic. The maximum biosynthetic activity of the Nocardia was observed in the medium containing 1-2 per cent of soybean meal and 2 per cent of glycerol. Under such conditions all the three biologically active substances formed. The contents of ristomycin, protease and pigments amounted to 562-649 microgram/ml, 26-30 PU/ml and 0.45-0.63 conditional units, respectively.     

Selection of the medium for the simultaneous synthesis of an antibiotic, protease and pigment by a Nocardia fructiferi culture

Using method of mathematical planning of experiment the culture medium ensuring the simultaneous intensive production of ristomycin, protease and violet pigment by Nocardia fructiferi has been worked out.     

Fibrinolytic properties of protease complex isolated from the culture fluid of Nocardia minima

The protease complex isolated form the Nocardia minima culture liquid was studied in vitro. The preparation had two different activities (fibrinolytic and activating), i.e. it was able to convert plasminogen into plasmin. At a concentration of 250 micrograms/ml and above the preparation lysed experimental thrombi. The fibrinolytic activity of the preparation was completely inhibited with normal human plasma.     

Application of sucrose-gradient centrifugation for selective isolation of Nocardia spp. from soil

AIMS: To devise and evaluate a method for selective isolation of the less abundant actinomycetes, Nocardia spp. in soil. METHODS AND RESULTS: This newly developed method is based on differentiating Nocardia from other actinomycete taxa by centrifugation. A water suspension of air-dried soil is centrifuged through a gradient consisting of 10, 20, 30, 40 and 50% sucrose at 240 x g for 30 min. The 20% sucrose layer, which is enriched with Nocardia spp., is then diluted and plated on humic acid-vitamin agar supplemented with antibacterial agents. The proposed method consistently achieved selective isolation of Nocardia spp. in all 14 soil samples tested, which accounted for 5-89% of the total microbial population recovered. Tentative taxonomic characterization based on a restriction fragment length polymorphism (RFLP) analysis of the 16S ribosomal DNA suggested that many of the soil isolates could belong to N. asteroides, N. salmonicida or N. uniformis. CONCLUSIONS: Differential centrifugation can successfully and efficiently isolate soil Nocardia populations that are suppressed by conventional dilution plating approaches. SIGNIFICANCE AND IMPACT OF THE STUDY: The development and application of new methodologies with which to isolate less-explored actinomycete taxa is important for improving our knowledge about their taxonomy, ecology and industrial applications.     

First environmental isolation of Cryptococcus neoformans var. neoformans and var. gatti from the Gharbia Governorate,Egypt

Flowers from two Eucalyptus camaldulensis trees in the Qutur area and one tree from the Tanta area yielded three isolates of Cryptococcus neoformans var. gattii. Pigeon and sparrow droppings were also investigated for the occurrence of C. neoformans within the study area. Ninety five isolates of the neoformans variety of C. neoformans were recovered from 550 samples of avian droppings. This revised version was published online in October 2005 with corrections to the Cover Date.     

First environmental isolation of Cryptococcus neoformans var. neoformans and var. gatti from the Gharbia Governorate, Egypt

Flowers from two Eucalyptus camaldulensis trees in the Qutur area and one tree from the Tanta area yielded three isolates of Cryptococcus neoformans var. gattii. Pigeon and sparrow droppings were also investigated for the occurrence of C. neoformans within the study area. Ninety five isolates of the neoformans variety of C. neoformans were recovered from 550 samples of avian droppings.     

Evaluation of double violet agar in the isolation of Klebsiella pneumoniae from river water.

A field evaluation of double violet agar for the isolation and presumptive identification of Klebsiella pneumoniae from water has been performed. Water from the North Oconee River, Clarke County, Ga., was cultured for presence of klebsiellae using the membrane filter technique. Colonies were presumptively identified as K. pneumoniae in the basis of their appearance on double violet agar. Such identifications were evaluated using appropriate biochemical tests. Once investigators have become familiar with cultural reactions on the medium, double violet agar can be used to indicate presence of K. pneumoniae in water with greater than 80% accuracy.