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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

The chemistry of natural products of the Rutaceae

Jabbar, Abdul January 1987 (has links)
Obligately anaerobic bacteria of the genus Bacteroides are important and abundant inhabitants of the rumen and hind gut of mammals. They are the most numerous group in the rumen and play a major role in fibre degradation with the rumen. They are phylogenetically remote from the better studied groups of facultatively anaerobic gut bacteria (eg. enterobacteria), but are closely related to the colonic Bacteroides. Interstrain conjugal transfer of a plasmid, pRRI4 (coding for tetracycline (Tc) resistance), from the multiple plasmid bearing B.ruminicola strain 223/M2/7 to F101, a rifampicin resistant mutant of B.ruminicola B 14, was demonstrated. pRRI4 was demonstrated to be self transmissible and carried the genes coding for TcR in B.ruminicola. Transformation of B.ruminicola F101 to TcR with pRRI4 was achieved using electroporation at frequencies up to 106 per mug DNA. Four other B.ruminicola strains were not transformed with this plasmid nor was a strain of B.uniformis. Similar procedures gave transformation of B.uniformis strains, but not B.ruminicola strains, with the E.coli:Bacteroides shuttle vectors pDP1 and pE5-2 at frequencies up to 107 per mug DNA. A nuclease assay was developed to determine the nuclease activity of a number of rumen bacteria and high nuclease activity in all B.succinogenes and five B.ruminicola strains was demonstrated. E.coli and B.uniformis strains were also transformed using electroporation by the shuttle vector, pRRI207, which has been constructed from a cryptic B.ruminicola plasmid (pRRI2, 3.4kbp) cut with EcoRI* , an E.coli vector plasmid (pHG165, 3.37kbp) carrying the pUC8 multiple cloning site, and the 4.2kbp Cc-EmRTc R* EcoRI region of pDP1. pRRI207 is capable of transforming B.uniformis, B.distasonis and B.ruminicola to clindamycin (Cc) resistance and E.coli to TcR (only expressed aerobically), and was the only construct from eleven different constructs obtained based on pRRI2 able to do so.
2

Comparison of Synthetic Versus Organic Herbicides/Insecticides on Arbuscular Mycorrhizal Fungi in Abelmoschus esculentus

Freidenreich, Ariel 14 June 2016 (has links)
Arbuscular mycorrhizal fungi (AMF) play a crucial role in improving the growth of a vast majority of plants. Past researchers have discovered that agricultural practices have a significant negative effect on the diversity of AMF. Arbuscular mycorrhizal fungi are reported to enhance plant nutrient uptake, stress tolerance, and soil aggregate formation which are key aspects of productive low-input farming. The objective of this study was to investigate the effects of four pesticides on the ability of AMF to colonize the roots of okra plants (Abelmoschus esculentus). The pesticides being tested include two synthetic chemicals (glyphosate and carbaryl) and two organic chemicals (neem oil and citrus oil). The tested parameters included crop yield, plant biomass, leaf matter CNP, and the percentage of mycorrhizal colonization in roots. The results of this study show that the organic chemicals had no significant effect on AMF colonization while the synthetic chemicals did have somewhat of a negative effect on colonization.

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