Comparison of various media and various methods for the growth and isolation of Pityrosporum pachydermatis

The pathogenic role of Pityrosporum pachydermatis in otitis externa of dogs and the related diagnostic problems are emphasized. We report results related to isolation, cultivation and identification of yeast. Agar nutritive glucosate with 1,5% of yeast extract has been showed as the best medium permitting identification in 24 hrs, associated with morfological test. Tween 80 integration (1%) to the medium permits to isolate lipolitic yeasts also.     

The evaluation of culture media for the routine isolation of gonococci

Summary The V.D. medium which is superior to the Peizer, Mueller and Difco media means no improvement over the old ascites-Levinthalagar plates in the routine isolation of gonococci.     

Evaluation of new culture media for rapid detection and isolation of salmonellae in foods.

Conventional methods for Salmonella detection in foods can require up to 6 and at least 4 days. We have observed that the total analysis time can be reduced to 48 h by using Salmosyst broth as a liquid medium for both preenrichment and selective enrichment and Rambach agar (RA), a new selective plate medium. In samples of artificially contaminated ground beef Salmonella enteritidis was detected at a concentration of 0.4 CFU/g (10 CFU/25 g) by both a conventional method and the new method. Of 519 samples of foods for sale, 38 were Salmonella positive by both methods while 471 were negative. Nine samples which were negative by the conventional method were positive by the Salmosyst-RA method, while one sample positive by the first method was negative by the last. Therefore, the Salmosyst-RA method showed 97.9% sensitivity compared with the 81.2% sensitivity of the conventional method. The new method was also highly specific (98% specificity) in presumptive identification of Salmonella colonies. Furthermore, a 6-h preenrichment in Salmosyst broth has been proved sufficient for the repair of heat-injured Salmonella cells and for subsequent recovery by selective enrichment. In conclusion, the Salmosyst-RA method shows several advantages over both conventional and rapid noncultural methods: (i) only two media are required instead of the five media for conventional methods; (ii) in real time it is comparable to other rapid noncultural methods, which require 30 to 31 h; (iii) it is highly sensitive and specific; and (iv) it allows the isolation of Salmonella strains which can be characterized by appropriate phenotypic and genotypic typing methods for epidemiological investigations.     

Cytostatic peptide isolation from culture media of mouse peritoneal exudate cells

It was found that the supernatant of mouse PEC culture medium (MCM) (both resident and casein-elicited cells) has an inhibitory effect in vitro on the incorporation of [3H]TdR into DNA of mouse spleen cells. The inhibitory effect in the MCM appears in the first 24 hr and also reaches its maximum value within this time. The inhibitory effect of this factor could not be demonstrated in the extract of freshly harvested M phi cells. The factors responsible for inhibition proved to be heat stable at 80 degrees C for longer than 30 min. Following heat treatment, the crude extract was separated into four fractions absorbing uv light at 280 nm using Sephadex G-25 column chromatography, and the most potent biologically active inhibitory factor was eluted in the last fraction. This fraction could also be obtained with a more effective permeation volume using Trysacryl GF 05 gel chromatography, and the active B fraction from this chromatography could be separated into four subfractions by isotachophoresis (ITP). The active fraction, which was obtained by Trysacryl GF 05 gel chromatography and further separated by ITP, was found to be highly inhibitory. It contained a peptide-like substance with a molecular mass of approximately 2.0 kDa and had an anionic character at pH 4.0. The inhibitory effect of MCM cannot be influenced either by inhibitory compounds of protein synthesis or by proteolysis blocking agents. Furthermore, the inhibitory effect is shown to be reversible and is more pronounced on B cells than on T lymphocytes.     

Structural and biochemical aspects of the effects of various media used for isolation and fractionation of mouse liver nuclei

We have carried out an electronmicroscopic study of replicas of the underside of culture cells. The techniques developed for the preparation of such replicas are described in detail. We find that the cells do not rest on the surface of the culture dish itself, but rather are attached to a protein film adsorbed from the culture medium. The underside of cells is usually rather smooth looking. It is difficult to clearly define the site of attachment of cells to their substrate. The features interpreted as attachment sites are often bored and diffuse. Heavy bundles of micro-filaments can be recognized in the sole plate of BHK cells. These bundles are usually parallel to the long axes of the cells, and often terminate in cell projections. They are only rarely encountered in the sole plate of transformed BHK cells.     

Evaluation of 2 culture media for the isolation and enumeration of motile Aeromonas in different kinds of water

In recent years an increasing incidence of Aeromonas-related cutaneous infections and gastroenteritis has raised a serious public health problem. It appeared therefore timely to define a specific method allowing the rapid isolation and enumeration of the bacteria in their various aquatic habitats. In this line of research we have compared the growth of Aeromonas originating from different aquatic sources and raised on two media, i.e. RS-agar and PXA-agar. Whatever the aquatic system we observed that the PXA-agar medium clearly was better adapted for a quick enumeration of Aeromonas.     

A streamlined method for the isolation and quantitation of nanomole levels of exported polyamines in cell culture media

A number of years ago, our laboratory published a method for the isolation of small amounts of polyamines from cell culture media using the ion-exchange resin Bio-Rex 70. We have used this technique extensively to study the export of putrescine and cadaverine from cultured mammalian cells. Unfortunately, this method was highly inefficient in isolating the polyamines spermidine and spermine and was incapable of recovering the acetylated polyamine N(1)-acetylspermidine. In response to these shortcomings, we modified our previous protocol to quantitatively isolate the polyamines N(1)-acetylspermidine, putrescine, cadaverine, N(1)-acetylspermine, spermidine, and spermine. The new method, which is much faster to perform and more efficient than the one previously described, employs the use of disposable minicolumns and a single resin washing step using a weak solution of sodium carbonate at pH 9.3. This new protocol also eliminates the column elution step in favor of directly derivatizing the polyamines with dansyl chloride on the ion-exchange resin. High-performance liquid chromatography analysis of the dansylated polyamines isolated by this procedure showed that 75% of N(1)-acetylspermidine and nearly 100% of the other polyamines present in nanomolar levels were recovered from small amounts of cell culture medium. This new protocol is a valuable new tool for the study of the intracellular/extracellular dynamics of polyamine pools in cultured cells. [A detailed laboratory protocol for this procedure (containing all of the information in this paper but in a condensed form) can be requested by e-mailing the authors.]     

Nutrient media for the isolation and accumulation of Listeria

Dried culture media for the isolation and accumulation of Listeria from pathological material and foodstuffs have been developed. The media are suitable for use in bacteriological and sanitary-hygienic practice. The optimum nutrient base has been selected: dried broth (from sprat hydrolysate), produced by the Research and Manufacturing Amalgamation "Culture Media". The optimum concentrations of ingredients, stimulating the growth of Listeria and inhibiting the growth of associated microbes, have been experimentally established. The samples of died accumulation and isolation culture media ensuring the growth of L. monocytogenes, diluted 10(-6), after 24-hour incubation at 37 degrees C have been obtained. The possibility of using these media for the bacteriological diagnosis of listeriosis in pregnant women has been demonstrated.