present research was for study on parasitic infections of domestic ruminants in golestan province. 234 samples of the gastrointestinal tracts contents, 260 livers, 180 lungs, 350 hearts and muscles, 300 abdominal cavities and 100 eyes for infection to helminthes, 800 blood samples for protozoa and external coats of 700 animals were examined for arthropoda. results showed that 19.74% of sheep ga...

This review summarizes current knowledge about genes whose products function in the transport of various cationic macronutrients (K, Ca) and micronutrients (Cu, Fe, Mn, and Zn) in plants. Such genes have been identified on the basis of function, via complementation of yeast mutants, or on the basis of sequence similarity, via database analysis, degenerate PCR, or low stringency hybridization. N...

The protozoa Cryptosporidium spp. are nowadays considered as the primary agents of intestinal diseases in humans and animals (Johnson et al., 1997). They have a worldwide distribution and can be found infecting more than 170 different animal species (O'Donoghue, 1995). They belong to the phylum Apicomplexa, parasite the gastrointestinal microvilli epithelium and or the bronchial tree (Fayer et ...

As microbial resistance to drugs continues to rise at an alarming rate, finding new ways to combat pathogens is an issue of utmost importance. Development of novel and specific antimicrobial drugs is a time-consuming and expensive process. However, the re-purposing of previously tested and/or approved drugs could be a feasible way to circumvent this long and costly process. In this review, we e...

HE MICROORGANISMS used for Vitamin B12 (cyanocobalamin) assay are LaCtobaciUus lewhmanniz (1), Euglena gracilis (2), Ochromonas maihamensis (3-5), and a mutant strain of Escherichia COli (E. coli 113-3) (6). Improvements in protozoan assays for B12 show such assays to be more sensitive and specific than bacterial assays (2, 7, 8). Ochromonas maihamensis is highly specific for true forms of B12 ...

Horowitz and co-workers (Horowitz, 1947; Teas, Horowitz & Fling, 1948; Fling & Horowitz, 1951) have determined the pathway of methionine synthesis in Neurospora crassa, from genetic analysis of methionine-requiring mutant strains; it involves conversion of cysteine, via cystathionine, into homocysteine, which is methylated to methionine. A similar scheme has been suggested for methionine synthe...