Studies on Johne's disease in Egyptian cattle.

Johne's disease (JD) or paratuberculosis is a serious problem of cattle industry worldwide. For a long period of time, Egypt was considered to be free of JD. In the present study, 2150 Egyptian cattle were examined clinically for JD. Among these, samples from 160 cows were investigated for the presence of Mycobacterium avium ssp. paratuberculosis using various laboratory methods including direct microscopic examination, faecal culture and polymerase chain reaction (PCR). According to the data obtained by the culture method, positive results could be observed for 75 cows from three of five investigated districts in Egypt. Comparably investigated samples from 40 cows of one known positive flock from Hesse, Germany yielded positive reactions for 20 cows. The present study is the first description of JD in Egypt.

Correlation of growth and aflatoxin production by Aspergillus flavus with some essential metals in gamma irradiated crushed corn.

The effects of gamma irradiation and some essential metals on growth and aflatoxin B1 production by Aspergillus flavus in crushed corn were investigated. The production of aflatoxin by A. flavus was influenced by the addition of zinc, copper or iron and the effect gradually decreased with increasing metal concentration from 0 to 300 ppm. A. flavus grew and depleted zinc, copper and iron at initial concentration of 100, 200 or 300 ppm. Presence of 100 ppm zinc, copper or iron plus gamma irradiation (0.5, 1.0, 2.0 kGy) enhanced the growth of A. flavus and the production of aflatoxin in contrast with irradiated samples alone. A. flavus was able to metabolize and deplete elements in all gamma-irradiated samples. These results suggest that stricter control of element levels in gamma irradiated grains could control aflatoxin contamination.

Preliminary experience in management of fecal incontinence caused by internal anal sphincter injury.

PURPOSE: Isolated injuries of the internal anal sphincter can cause fecal incontinence. With the advent of ultrasound, which accurately delineates the anatomy of the anal sphincters, internal sphincter injuries can be diagnosed more precisely. The purpose of this study was to evaluate the outcome of direct repair of isolated internal anal sphincter defects. METHODS: Eight patients (6 males; median age, 37 years) with clinically and sonographically proved internal anal sphincter defects were the subject of this study. Patients had different degrees of incontinence that failed to respond to medical treatment. All patients had their sphincters repaired by direct apposition using coated Vicryl 2-0 stitches. A strict postoperative regime that avoided stretch of the sphincter for one month was adopted. RESULTS: At a median follow-up period of 15 months, continence improved in all patients, and two achieved full continence. None of the patients wore pads. Mean continence score improved significantly from 4 to 12 and 11 at 6 and 12 postoperative months, respectively (P < 0.0001, paired t-test). CONCLUSION: Despite the limited number of patients and the short follow-up, the preliminary results of repair of isolated internal sphincter defects are satisfactory.

Use of polymerase chain reaction to simultaneously detect and type bovine viral diarrhoea viruses isolated from clinical specimens.

The techniques of indirect immunofluorescence (IF), immuno-peroxidase (IP) staining and the one-step reverse transcriptase polymerase chain reaction (RT-PCR) were compared for detection of 102 isolates of bovine viral diarrhoea virus (BVDV) in infected cell cultures. The BVDV was obtained from bovine clinical specimens, including sera, buffy coats and tissues, submitted from farms located in the States of Iowa and Wisconsin, United States of America. The IF technique detected 88/102 (86.3%) of the viral isolates, whereas IP staining detected an additional 4 isolates (92/102; 90%). The one-step RT-PCR using primers derived from the 5' untranslated region of the BVDV genome detected 102/102 (100%) of the BVDV isolates. A second-round PCR utilising another pair of PCR primers from the 5' untranslated region, allowed rapid genotyping of BVDV. The procedure used showed that the PCR assay based on the 5' untranslated region of the virus genome is the most sensitive indicator for BVDV detection in cell culture, and is also of considerable epidemiological importance since it allowed rapid genotyping of BVDV isolated from clinical specimens. In addition to detection and genotyping of BVDV isolated from clinical specimens, the RT-PCR procedure can be used for routine screening of locally produced and imported biologicals for BVDV contamination. However, the procedure requires further refinement to enable direct application on the clinical specimen.

Utilization of waste products of dehydrated onion industry for production of fodder yeast by Saccharomyces cerevisiae.

One strain of Saccharomyces cerevisiae was selected from different yeasts, isolated from black strap molasses. This microorganism was cultivated on seven fermentation media for the production of protein. Medium I exhibited the highest potentiality for formation of protein. Therefore strain 1 of S. cerevisiae and medium I were used for further studies in the formation of protein. Factors controlling production of protein were explored. The required incubation period for the fermentation process was 72 hrs, while the initial pH value of the medium was 6.0. Sucrose supported the microorganism for higher production of protein (40.96%), while the best concentration of sucrose was shown to be 10.0 g/l. The best inorganic and organic nitrogen sources for protein formation were (NH4)2HPO4, (NH4)3PO4 and yeast extract, respectively. The best concentrations of (NH4)2HPO4 and yeast extract, supporting protein formation, were 5.0 g/l and 10.0 g/l, respectively. Addition of MgSO4, ZnSO4, ferrous ammonium sulphate, copper sulphate, biotin, Ca-pantothenate, thiamine, pyridoxine, and inositol to the synthetic medium did not markedly influence high level of protein formation. Glutamic acid was the best amino acid, supporting protein formation by S. cerevisiae. Onion juice was found to be a good medium, after deletion of inhibitory volatile sulphur organic compounds, for the production of protein by S. cerevisiae. Addition of (NH4)2HPO4 to the best concentration of onion juice assisted the onion medium in production of fodder yeast, containing high level of protein. Addition of MgSO4 to onion juice and (NH4)2HPO4 did not increase the total nitrogen of the biomass. Fodder yeast, produced by onion juice medium, contained more valuable ingredients than fodder yeast, produced by synthetic medium.

Carbomycin, a macrolide antibiotic.

Carbomycin is produced by Streptomyces halstedii. It was produced in a medium containing the following ingredients (g/l): soybean meal, 30.0; glucose, 22.0; NaCl, 1.0; CaCO3, 5.0; CoCl2 . 6 H2O, 0.005; and lard oil, 4.0. Influence of trace elements on the biosynthesis of carbomycin was recorded. Methods of extraction and purification were given in the review article. Chemical and physical properties of carbomycin were also described. A microbiological assay method for carbomycin determination was described. Biosynthesis of carbomycin was reported. Mechanism of action of carbomycin on micro-organisms was also given in the review article.

Microbiological production of acetone-butanol by Clostridium acetobutylicum.

Trials succeeded in raising the efficiencies of the fermentation medium, used in the fermentative production of acetone-butanol by Clostridium acetobutylicum. Egyptian black strap molasses (50.0% sugars) was suitable as carbon source in the fermentation medium, and (NH4)2SO4 was utilized with great success as inorganic nitrogen source. 140.0 g/l black strap molasses (about 7.0% sugars) and 3.0 g/l (NH4)2SO4 were the optimum concentrations for obtaining good yields of acetone and butanol. Molasses and (NH4)2SO4 were preferred because they are cheaper than the other carbon and organic nitrogen sources, used in the fermentative production of acetone-butanol. The percentage increase of the total solvents produced in the fermentation (production medium) was increased by 64.0. The slop (by-product of the acetone-butanol fermentation after distillation) was re-used in the fermentation medium as organic nitrogen source and supported the microorganisms for a good production of acetone and butanol, while when stillage was used in the production medium, the total solvents output was less than that produced in the medium containing slop.

Mode of action of gentamicin antibiotics produced by Micromonospora purpurea.

Gentamicin antibiotics were produced fermentatively by Micromonospora purpurea. They were separated into gentamicin C1, C1a and C2 by paper chromatographic technique, using chloroform, methanol, and 17.0% of NH4OH (2: 1: 1 v/v) as developing solvent. The different antibiotics showed variable antimicrobial activities. The gentamicin antibiotics inhibited the biosynthesis of DNA and RNA of the proteins, present in the cells of Staphylococcus aureus.

The fermentative production of oxytetracycline on industrial by-products by Streptomyces rimosus 12907.

Three strains of Streptomyces rimosus were grown on four different media. The one suitable for the production of oxytetracycline by Streptomyces rimosus 12907 was modified by black strap molasses, fodder yeast (40% total protein) and rice bran. The volume of the fermentation medium was sealed up in a 1200-litre fermentor aerated with sterile air obtained from a system used in the purification of air. 850 g crude oxytetracycline was obtained when the fermented medium (700 litres) was extracted with 1-butanol.

Gentamicins.

Gentamicin is a new broad-spectrum antibiotic, basic and water-soluble, produced and developed by Schering Corporation-Bloomfield, New Jersey (1967 and 1968). It is produced by Micromonospora purpurea, a member of a genus of microorganisms from which no other antibiotics have been derived. Paper chromatographic techniques showed the components of gentamicin complex designated as C', C'a, and C2. Gentamicins are bactericidal antibiotics, active in vivo in low concentrations against a wide spectrum of both Gram-positive and Gram-negative organisms. Among the responsive Gram-positive groups of microorganisms are Staphylococcus aureus including many resistant penicillinase producing strains and group A betahemolytic Streptococci. Among the clinically more important species of Gram-positive organisms responsive to gentamicin are both indole-positive and indole-negative Proteus, Pseudomonas, Escherichia coli, Aerobacter, Klebsiella, Salmonella, and Shigella. The production of gentamicins was improved by adding cobalt to the growth medium.

The fermentative production of acetone-butanol by Clostridium acetobutylicum.

Fourteen different media were used in the fermentative production of acetone-butanol. The highest total yields were achieved in medium I. Potato starch and soluble starch were suitable as carbon sources. The best concentrations of potato starch and soluble starch were 500.0 and 10.0 g/l, respectively. Peptone was the most favourable nitrogen source. The best concentration of peptone was 4.0 g/l. Calcium carbonate in 3.6 g/l acted as buffering agent in the fermentation process. The best initial pH value of the fermentation medium was 6.0. The optimum temperature was 32--33degreesC. The fermentation process required 120 h to obtain maximum yields of acetone-butanol.

Effect of sodium arsenite on the biosynthesis of mitomycins by Streptomyces caespitosus and mode of action of mitomycin C on Bacillus subtilis NRRL B-543.

Addition of different concentrations of sodium arsenite to the fermentation medium used for the production of mitomycin antibiotics by Streptomyces caespitosus hindered the biosynthesis of mitomycins and led to the accumulation of 2-oxoglutarate, pyruvate and acetone. Mitomycin C isolated and purified using thin-layer chromatography in low concentration of about 0.1 mug/ml did not affect the RNA, DNA and protein biosynthesis of the growing Bacillus subtilis, while at 10 mug/ml mitomycin C markedly affected RNA, DNA and protein biosynthesis.