Yeast is an ideal host system for studying exogenous eukaryotic gene expression and for studying gene structures from recombinant plasmid DNAs and yeast artificial chromosomes (YACs). Many yeast expression studies may also require the altering of the genome itself by homologous recombination. All these studies require the screening for positive transformants and the most popularly used method o...

PCR products of 1.8 kb were generated with DNAs from all Escherichia coli H7 strains tested by using oligonucleotide primers which flank the fliC gene. Three RsaI digestion profiles of these PCR products were evident on agarose gels; the first occurred with serotype O55:H7, O157:H7, or nonmotile (NM) strains, the second occurred with serotype O1:H7 and O18:H7 strains, and the third occurred wit...

Of the bacterial antagonists thus far known to be produced by microorganisms, the most effective in bactericidal action against Brucella abortus is the culture filtrate from a strain of Penicillium notatum (Kocholaty, 1942). Another antibacterial substance, penicillin, also obtained from a culture of a strain of Penicillium notatum, but with very little potency against Brucella abortus, has bee...

Brucellosis is endemic in most parts of Egypt, where it is caused mainly by Brucella melitensis biovar 3, and affects cattle and small ruminants in spite of ongoing efforts devoted to its control. Knowledge of the predominant Brucella species/strains circulating in a region is a prerequisite of a brucellosis control strategy. For this reason a study aiming at the evaluation of the phenotypic an...

conclusions the results of this study showed that pcr–rflp technique was a fast and applicable method especially for separation, detection and differentiation between species of b. melitensis and b. abortus biovars in blood sample. also the presented data showed that b. melitensis biovar 1 was the prevalence biovar. background brucella is an intracellular parasite of the disease brucellosis thr...

Most members of the genus Brucella show strong urease activity. However, the role of this enzyme in the pathogenesis of Brucella infections is poorly understood. We isolated several Tn5 insertion mutants deficient in urease activity from Brucella abortus strain 2308. The mutations of most of these mutants mapped to a 5.7-kbp DNA region essential for urease activity. Sequencing of this region, d...

Brucella spp. are facultative intracellular pathogens that have the ability to survive and multiply in professional and non-professional phagocytes, and cause abortion in domestic animals and undulant fever in humans. Several species are recognized within the genus Brucella and this classification is mainly based on the difference in pathogenicity and in host preference. Brucella strains may oc...

Moraxella (Branhamella) catarrhalis, a causative agent of otitis media, sinusitis, and exacerbation of bronchitis, has acquired widespread ability to produce beta-lactamase and can be nosocomially transmitted. The typing methods used in epidemiological analyses of M. catarrhalis are not optimal for genetic analyses. Two methods, a multiple-locus Southern blot (SB) method and a single-locus PCR-...