Epidemiology and risk factors of brucellosis in Alexandria governorate

This study aimed to describe the trend and to identify possible risk factors for brucellosis in Alexandria in northern Egypt. We enrolled 72 confirmed cases of brucellosis and 144 age-matched controls in this study. Participants were interviewed at home using a structured questionnaire. Working with animals, breeding goats and eating ice cream bought from street vendors were significantly associated [P < 0.05] with brucellosis by univariate and multivariate analysis. Contact with infected animals and their products was the most important method of transmission

Effect of the plant Azolla pinnata on survival, growth rate, fecundity and hatchability of egg-masses of Biomphalaria alexandrina snails.

Data indicated that Azolla pinnata plants variously reduce the growth rate of Biomphalaria alexandrina snails expressed as net increase in shell diameter (direct or indirect exposure). The plant density played an important role in this respect. The higher the plant density was the lower the growth rate and vice versa. Too, indirect exposure of newly hatched B. alexandrina resulted from exposed treated eggs reduced the growth rate of these snails. Data revealed that direct and/or indirect exposure to the abnormal high density (50,000 plants/L) resulted in complete kill of B. alexandrina snails after two weeks from continuous exposure. Snails exposed directly to Azolla at 50,000 and 25,000 plants/L failed to lay eggs. On the other hand, sanils exposed to 10,000 plants/L laid few eggs, resulted in low reproductive rate (57.94) compared with unexposed ones (110.6). The same trend of results was recorded with hatchability of Biomphalaria eggs.

Utilization of industrial and agricultural by-products for fungal amylase production.

Attempts were made for using industrial and agricultural by-products and wastes as carbon and nitrogen sources in fermentation medium for alpha-amylase production by Aspergillus niger NRRL-337. The original carbon source of the basal medium was replaced by one of the following materials: rice bran, wheat bran, corn bran, corn starch, cane molasses, and glucose syrup. Rice bran proved to be the best carbon source that secured the highest amylase activity. The nitrogen source of the basal medium was then replaced by different cheap materials, viz: dried yeast, corn steep liquor, gluten-30, gluten-50, and corn steep precipitate. Corn steep precipitate proved to be superior in amylase production. In consideration of these results an economical medium that secured high activity, containing the following ingredients, was suggested: 2.5% corn steep precipitate, 7.2% rice bran, 0.1% MgSO4, 0.1% KH2PO4, and 0.1% CaCO3. From this medium fungal amylase was precipitated and purified. The pure enzyme gave the highest activity at 40 degrees C and pH 4.3.

Studies on protein production by yeasts. I. Isolation, identification, and screening of efficient strains.

A collection of yeast strains was isolated from different fresh fruits and foodstuffs. Isolates were purified and completely identified up to the species. The ninety isolated yeast strains were screened according to their yield and total nitrogen content, using molasses medium as an available cheap raw-material for yeast propagation.

Studies on protein production by yeasts. III. Effects of different levels of nitrogen and phosphorus.

The four strains of yeasts that gave good growth in molasses medium, short generation time, and high protein content were selected for further studies in a trial for increasing their yield and protein content. Therefore, the effect of different levels of ammonium sulphate and potassium dihydrogen phosphate on the growth and protein synthesis of the strains was investigated, using molasses as a source of carbon. The results revealed that the most suitable concentrations of ammonium sulphate in the propagation medium lie between 0.40 to 0.55% for the production of high yield and protein content of strains S. cerevisiae (Gr. 104), C. utilis (F. 86), C. tropicalis (F. 35), and H. anomala (Gr. 5). The optimum concentration of potassium dihydrogen phosphate lies between 0.2 to 0.3% for the same strains. S. cerevisiae (Gr. 104) seemed to be the most efficient strain that gave the best growth, high percentage of protein, and essential amino acids in molasses medium.

Studies on protein production by yeasts. IV. Incremental feeding modulus.

S. cerevisiae Gr. 104 which seemed to be the most efficient strain in protein production, was used for investigating its optimum incremental feeding modulus that gives the highest economical yield. Therefore, different hourly rates of incremental feeding, ranging from 1.14 to 1.22, were used and the yeast yield for each rate was determined. Experiments were carried out in a laboratory fermentor vessel of 5 liter capacity, using molasses, ammonium sulphate, and potassium dihydrogen phosphate as feeding substances with optimum pH, temperature, and effective aeration. The optimum incremental feeding for this strain (which is the rate of molasses feeding corresponding to the exponential growth rate) was found to be 1.18. At this rate the best economical use of the substrate was obtained with the production of yield, close to the theoretically calculated yield.