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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Survival of Animal-derived Campylobacter Strains in Raw and Pasteurized Milk, and the Roles of Capsule in Campylobacter Survival in vitro, and in Chick Colonization

Xiong, Jiajuan 10 September 2009 (has links)
Campylobacter spp. is a major cause of acute bacterial gastroenteritis in the developed countries. It can survive in a wide range of environments, raw milk and poultry are major reservoirs. Survival of animal-derived Campylobacter strains, including six C. jejuni and six C. coli, was examined in raw and pasteurized milk at 4oC. Most (11/12) of the Campylobacter strains survived in both raw and pasteurized milk for at least 14 days. The most resistant strain, a C. jejuni from a dairy cow, retained its viability over eight weeks in pasteurized milk, while the most sensitive strain showed a > 5-log10 CFU/ml reduction in raw milk after one week. The majority (9/12) of the strains survived better in pasteurized milk than in raw milk, while the opposite was observed for two C. coli strains. The findings indicate that Campylobacter spp. can survive in milk for at least 14 days at 4oC and that survival is strain-dependent. To elucidate mechanisms underlying such adaptation, we characterized the role of capsule in Campylobacter survival in milk and other media, and in chick colonization. Three capsule-deficient mutants (kpsM::kanr), C. coli 6979M2, C. jejuni BS142M2 and C. jejuni SC1453M2 were constructed by site-specific mutagenesis. Compared to the wild type strains, the colonies of the mutants were smaller, more convex, and shinier on agar media; the mutants were more sensitive to desiccation and two (C. coli 6979M2 and C. jejuni BS142M2) grew slower in broth. These two mutants were also more sensitive to certain antibiotics than their wild type counterparts. The survival of the mutants in distilled water, raw and pasteurized milk was comparable to survival of their wild type counterparts, as was the ability of the bacteria to transform to nalidixic acid resistance via transformation. In chick colonization experiment, C. coli 6979 M2 showed > 3log10 reduced cell density in cecal contents than its parent strain. These results suggest that capsule is essential for C. coli in chick colonization and responsible for colony morphology on solid agar and can protect cells from desiccation, but its impact on growth rate, competence and antibiotic resistance is strain-dependent.
2

Genetic analysis of Bombyx mori using Random amplified Polymorphic DNA (RAPD) markers

Nagaraja, G M 12 1900 (has links)
Polymorphic DNA (RAPD) markers
3

Molecular cloning and characterization of wheat triticin cDNA and studies on the expression of triticin like proteins.

Srinivas, B 09 1900 (has links)
cDNA and studies on the expression of triticin like proteins.
4

Characterisation of a novel extracellular starch hydrolysing enzyme of Aspergillius niger.

Suresh, C 11 1900 (has links)
Hydrolysing enzyme of Aspergillius niger
5

Studies on production of Capsaicin in immobilized cells and placental tissues of Capsicum Annuum and C. Frutescens

Johnson, Sudhakar T 10 1900 (has links)
Studies on production of Capsaicin
6

Studies on Agrobacterium tumefaciens-mediated genetic transformation in some important Indian selections of coffee.

Naveen, K S 11 1900 (has links)
Genetic transformation in some important Indian selections of coffee
7

Studies on polygalacturonase of aspergillus species and genetic characterisation of a poly galacturonase over producing mutant.

Kavitha, R 05 1900 (has links)
Genetic characterisation of a poly galacturonase over producing mutant.
8

Studies on anaerobic cellulolytic bacteria with special reference to cellulase production.

Tirumale, Sharmila 09 1900 (has links)
Bacteria with special reference to cellulase production.
9

Characterization of Fusarium oxysporum f.sp. cubense isolates and marker assisted screening for wilt resistant clones of Banana cv. 'Nanjangud Rasabale'

Kumar, Bhuvanendra H 11 1900 (has links)
Marker assisted screening for wilt resistant clones of Banana cv. 'Nanjangud Rasabale'
10

Induction of systemic resistance in pearl millet against downy mildew disease and the mechanism of resistance

Shivakumar, P D 11 1900 (has links)
Downy mildew disease and the mechanism of resistance

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