Dry medium for isolating Clostridium perfringens

The possibility of using blood substitutes (hydrolysin, casein hydrolysate "tsolipk" and amino peptide) with expired shelf life as a culture medium for the isolation of Cl. perfringens has been studied. Dry culture medium based on these inedible products has been developed. To stimulate bacterial growth, fodder yeast extract has been used. The suppression of the growth of extraneous microflora is ensured by the use of antibiotics: polymyxin sulfate and mycerin sulfate. The recommended medium is not inferior in its quality (sensitivity, rapidity of growth, differentiating and inhibiting properties, etc.) to media based on meat and casein. The use of the newly developed medium is economically grounded and allows one to obtain standard results.     

Selective media for isolating Pseudomonas aeruginosa

The comparative study of 4 selective media (medium containing N-cetylpyridinium chloride, acetamide agar, cetrimide agar, medium containing irgasane) showed that their use permitted one to enhance the isolation of P. aeruginosa, especially pigment-free forms, from pathological material and to reduce the time of their isolation by 24-48 hours. Of all the media subjected to testing medium containing N-cetylpyridinium chloride and acetamide medium proved to have the highest selectivity.     

New medium for isolating iron-oxidizing and heterotrophic acidophilic bacteria from acid mine drainage.

A new solid medium is described for growing iron and heterotrophic bacteria from acid mine drainage (AMD). Examination of AMD from five states revealed several kinds of colonies of iron-oxidizing bacteria: (i) smooth, (ii) smooth with secondary growth sectors or branching, (iii) star-shaped, (iv) radiating lobe, and (v) flat-rough. All AMD samples yielded whitish colonies that could not use ferrous iron, sulfur, or hydrogen, nor could they grow on nutrient agar, brain heart infusion agar, or Trypticase soy agar. Glucose and sucrose supported growth if the sugar-salts medium was at pH 3.0. The new iron medium has several advantages over others: (i) easy preparation, (ii) rapid growth, (iii) larger colonies, (iv) differentiation of colony morphology, and (v) detection of a new group of heterotrophic acidophilic bacteria.     

Flagellation of Salmonella typhimurium treated with nalidixic acid

Filamentous cells of Salmonella typhimurium, obtained after treatment with nalidixic acid in the exponential phase of growth, elongated up to 10 micron, corresponding to 4 unit cell lengths, per nucleoid. During elongation, division of nucleoids and septum formation did not occur, but de novo formation of flagella continued. Most of the filamentous cells were motile, and flagella were evenly distributed on their surface.     

A selective medium for isolating Rhizoctonia solani from soil

Ko & Hora's (1971) selective medium (FM) for counting Rhizoctonia solani propagules from soil has been modified. FM medium minus gallic acid and fenaminosulf i.e. mineral antibiotic (MA) medium, was amended with inhibitors and fungicides at different concentrations. The modified medium consisting of MA + gallic acid (400 μg ml^-1) + fosetyl-Al (250μgml^-1) was found most efficient in selective isolation of R. solani from soil even in the presence of Macrophomina phaseolina (Rhizoctonia bataticold) and other soil mycoflora. This amended medium was effective in isolating R. solani from soil even when the number of propagules of M. phaseolina present was 10 times greater. The sensitivity of this medium was five times better than Ko & Hora's medium.     

Induction of bacteriophage lambda with oxolinic and nalidixic acid

Oxolinic acid induces bacteriophage lambda similarly to other agents interfering with the normal replication cycle of the bacterial chromosome. This effect appears at a concentration more than twenty times lower than that of nalidixic acid.     

A new selective medium for isolating Pseudomonas spp. from water

A new medium, pseudomonas selective isolation agar, was developed to isolate Pseudomonas spp. from water. It consists of 350 micrograms of nitrofurantoin per ml and 2 micrograms of crystal violet per ml in a nutrient agar base. It is more selective for Pseudomonas spp. than are available commercial media. Its ingredients are inexpensive and readily available, and it is easy to prepare.     

Metal complexes of the antibiotic nalidixic acid

The preparations and spectral properties are reported of a range of complexes of nalidixic acid (= HNal) with some metal ions in the series CrZn and also Mg, Ca, Cd, Hg and Pd(II). Most of the compounds formed by the divalent metal ions had a 2:1 HNal:metal ratio, and some of them are polymeric. Complexes in which the carboxylate group of HNal functions as a chelate were isolated with Cu(II), Pd(II), Fe(III) and Cr(III).