Spelling suggestions: "subject:"enetic engineering"" "subject:"enetic ingineering""
341 |
Gene expression in brains from red jungle fowl (Gallus gallus) that differ in fear responseJöngren, Markus January 2008 (has links)
<p>The fear response of two different captive populations of red jungle fowl (rjf, Gallus gallus) was measured in three different tests, a ground predator test, an aerial predator test and a tonic immobility test. The two populations originated from Copenhagen zoo (Cop) and Götala research station (Got) but had been kept together for four generations. Earlier generations had a confirmed difference in fearfulness where the Cop birds exhibited a higher degree of fear response than Got birds (Håkansson and Jensen, 2005; Håkansson et al., 2007). The most and least fearful birds of each sex and population were identified and used in a gene expression study. The midbrain regions from the candidate birds were collected and RNA was isolated from each brain. The RNA was then reversed transcribed to cDNA which was used in a cDNA microarray experiment. 13 significantly differentially expressed genes were found between the fearful and non-fearful females. Among others were the neuroprotein Axin1, two potential DNA/RNA regulating proteins and an unknown transcript in the Quantitative Trait Locus 1(QTL 1), a well studied QTL on chromosome one with substantial effect on both behaviour and morphology during domestication (Schütz et al., 2002). This thesis succeeds in finding a difference in gene expression between fearful and non fearful female rjf but not between males. It fails in identifying gene expression differences between the two populations. Finally, the found differentiated genes suggest a potential molecular mechanism controlling the fear response in fowl.</p>
|
342 |
Breeding for resistance to barley net blotch (pyrenophora teres) /Jonsson, Rickard. January 2001 (has links)
Thesis (doctoral)--Swedish University of Agricultural Sciences, 2001. / Thesis statement in Swedish and English abstract inserted. Based on 4 previously prepared or published papers reprinted here. Includes bibliographical references.
|
343 |
Structural and biochemical analysis of the essential spliceosomal protein Prp8Ritchie, Dustin Blaine. January 2010 (has links)
Thesis (Ph.D.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Biochemistry. Title from pdf file main screen (viewed on February 12, 2010). Includes bibliographical references.
|
344 |
Investigation of the limitations of viral gene transfer to murine embryonic stem cellsChilton, Jamie Meredith. January 2008 (has links)
Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Joseph Le Doux; Committee Member: Anthanassios Sambanis; Committee Member: David Archer; Committee Member: Michelle LaPlaca; Committee Member: Steve Stice; Committee Member: Todd McDevitt. Part of the SMARTech Electronic Thesis and Dissertation Collection.
|
345 |
Plant defence genes expressed in tobacco and yeast /Becker, John van Wyk, January 2002 (has links)
Thesis (M. Sc.)--University of Stellenbosch, 2002. / Includes bibliographical references. Also available via the Internet.
|
346 |
Gene expression in brains from red jungle fowl (Gallus gallus) that differ in fear responseJöngren, Markus January 2008 (has links)
The fear response of two different captive populations of red jungle fowl (rjf, Gallus gallus) was measured in three different tests, a ground predator test, an aerial predator test and a tonic immobility test. The two populations originated from Copenhagen zoo (Cop) and Götala research station (Got) but had been kept together for four generations. Earlier generations had a confirmed difference in fearfulness where the Cop birds exhibited a higher degree of fear response than Got birds (Håkansson and Jensen, 2005; Håkansson et al., 2007). The most and least fearful birds of each sex and population were identified and used in a gene expression study. The midbrain regions from the candidate birds were collected and RNA was isolated from each brain. The RNA was then reversed transcribed to cDNA which was used in a cDNA microarray experiment. 13 significantly differentially expressed genes were found between the fearful and non-fearful females. Among others were the neuroprotein Axin1, two potential DNA/RNA regulating proteins and an unknown transcript in the Quantitative Trait Locus 1(QTL 1), a well studied QTL on chromosome one with substantial effect on both behaviour and morphology during domestication (Schütz et al., 2002). This thesis succeeds in finding a difference in gene expression between fearful and non fearful female rjf but not between males. It fails in identifying gene expression differences between the two populations. Finally, the found differentiated genes suggest a potential molecular mechanism controlling the fear response in fowl.
|
347 |
Expression of a modified xylanase in yeastMchunu, Nokuthula Peace January 2009 (has links)
Submitted in fulfillment for the requirement of a Degree of Master of Technology: Biotechnology, in the Department of Biotechnology and Food Technology, Faculty of Applied Sciences, Durban University of Technology, Durban, South Africa, 2009. / Protein engineering has provided a key for adapting naturally-occurring enzymes for industrial processes. However, several obstacles have to be overcome after these proteins have been adapted, the main one being finding a suitable host to over-express these recombinant protein. This study investigated Saccharomyces cerevisiae, Pichia pastoris and Escherichia coli as suitable expression hosts for a previously modified fungal xylanase, which is naturally produced by the filamentous fungus, Thermomyces lanuginosus. A xylanase variant, NC38, that was made alkaline-stable using directed evolution was cloned into four different vectors: pDLG1 with an ADH2 promoter and pJC1 with a PGK promoter for expression in S. Cerevisiae, pBGP1 with a GAP promoter for expression in P. pastoris and pET22b(+) for expression in E. Coli BL21 (DE3). S. Cerevisiae clones with the p DLG1-NC38 combination showed very low activity on the plate assay and were not used for expression in liquid media as the promoter was easily repressed by reducing sugars used during production experiments. S. cerevisiae clones carrying pJC1-NC38 were grown in media without uracil while P. Pastoris clones were grown in YPD containing the antibiotic, zeocin and E. Coli clones were grown in LB with ampicillin. The levels of xylanase expression were then compared between P. Pastoris, S. cerevisiae and E. coli. The highest recombinant xylanase expression was observed in P. Pastoris with 261.7U/ml, followed by E.coli with 47.9 U/ml and lastly S. cerevisiae with 13.2 U/ml. The localization of the enzyme was also determined. In the methylotrophic yeast, P. Pastoris, the enzyme was secreted into the culture media with little or no contamination from the host proteins, while the in other hosts, the xylanase was located intracellularly. Therefore in this study, a mutated alkaline stable xylanase was successfully expressed in P. Pastoris and was also secreted into the culture medium with little or no contamination by host proteins, which favours the application of this enzyme in the pulp and paper industry.
|
348 |
Overexpression and partial characterization of a modified fungal xylanase in Escherichia coliWakelin, Kyle January 2009 (has links)
Submitted in complete fulfillment for the Degree of Master of Technology (Biotechnology)in the Department of Biotechnology and Food Technology, Faculty of Applied Sciences, Durban University of Technology, Durban, South Africa, 2009. / Protein engineering has been a valuable tool in creating enzyme variants that are capable of withstanding the extreme environments of industrial processes. Xylanases are a family of hemicellulolytic enzymes that are used in the biobleaching of pulp. Using directed evolution, a thermostable and alkaline stabl xylanase variant (S340) was created from the thermophilic fungus, Thermomyces lanuginosus. However, a host that was capable of rapid growth and high-level expression of the enzyme in large amounts was required. The insert containing the xylanase gene was cloned into a series a pET vectors in Escherichia coli BL21 (DE3) pLysS and trimmed from 786 bp to 692 bp to remove excess fungal DNA upstream and downstream of the open reading frame (ORF). The gene was then re-inserted back into the pET vectors. Using optimized growth conditions and lactose induction, a 14.9% increase in xylanase activity from 784.3 nkat/ml to 921.8 nkat/ml was recorded in one of the clones. The increase in expression was most probably due to the removal of fungal DNA between the vector promoter and the start codon. The distribution of the xylanase in the extracellular, periplasmic and cytoplasmic fractions was 17.3%, 51.3% and 31.4%, respectively. The modified enzyme was then purified to electrophoretic homogeneity using affinity chromatography. The xylanase had optimal activity at pH 5.5 and 70°C. After 120 min at 90°C and pH 10, S340 still displayed 39% residual activity. This enzyme is therefore well suited for its application in the pulp and paper industry.
|
349 |
Regeneration and biotransformation of some members of the Cucurbitaceae.Abrie, Amelia Letitia. 23 December 2013 (has links)
Five cultivars, all belonging to the family Cucurbitaceae, have been tested for the
ability to regenerate shoots or somatic embryos from cotyledonary explants. The
influence of several combinations of growth regulators on regeneration from
cotyledonary and other explants was tested.
No regeneration was obtained from the two cultivars Cucurbita maxima Duch. cv
A-Line and Cucurbitapepo L. cv Rolet. Somatic embryos developed on Cucurbita
maxima Duch. cv Chicago Waited, a Hubbard squash. A shoot regeneration
response was observed for the cultivar Cucumis sativus L. cv Ashley, but the
frequency was low and results could not be repeated in subsequent experiments. A
reliable shoot regeneration protocol was developed for Cucumis melo L. cv Hales
Best 36.
The influence of the antibiotics kanamycin sulphate and cefotaxime on shoot
regeneration from cotyledonary explants of Cucumis melo L. cv Hales Best 36 was
tested. The plasmid pBI121 was transferred from Escherichia coli strain HB101 into
Agrobacterium tumefaciens strain LBA4404 via a triparental mating. The plasmid
pBI121, contains the screenable marker gene β-glucuronidase (GUS) and the
selectable neomycin phosphotransferase-II gene (NPT-II) that confers kanamycin
resistance. Cotyledonary tissue was transformed using this Agrobacterium
tumefaciens transformation system. The influence of co-cultivation time, inoculation
time and the wound factor acetosyringone on transformation was established. Rooted
plantlets were regenerated from transformed cotyledonary tissue placed on
kanamycin supplemented regeneration media. Plantlets tested positive for the
presence of the GUS gene, using fluorometric and histochemical assays.
The developed protocol was used to transform Cucumis melo cv Hales best 36 with
the pat gene that provides resistance to the herbicide Ignite®. A selection medium
was developed containing phosphinothricin, the active ingredient of the herbicide Transformants were selected on this medium and five lines were recovered. These
plants were acclimatized and the herbicide resistance was confirmed in greenhouse
spray tests. The ploidy level of these plants was deduced from indirect evidence of
micro- and macroscopic characteristics that have been shown to have a correlation
with the chromosome number of melon plants.
The five lines were subjected to molecular analysis. The polymerase chain reaction
was used to give an indication of the transformed nature of the selected plants.
Agarose gel electrophoresis confirmed that the correct size band could be obtained
from the putative transformants and the presence of pat in the product was verified
using a non-radioactive system for nucleic acid analysis. Stable gene insertion into
the genome of the plant was verified with a Southern blot of the total genomic DNA.
This was achieved by hybridising a radioactively labelled ³²P probe specific for the
pat gene to a blot of restriction digested plant DNA. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1998.
|
350 |
Promoters for sugarcane transformation : isolation of specific sequences and evaluation of rolC.Groenewald, Sarita. 23 December 2013 (has links)
Increasing the sucrose yield and the disease resistance of plants are two major
objectives of the transgenic sugarcane plant programme in South Africa. The
sugarcane culm has thus been identified as one of the main target areas for
transgene expression. A shortage of reliable promoter elements as well as patent
limitations have necessitated the isolation of promoters that are preferentially
expressed in the sugarcane culm. In the present study two different approaches were
followed to isolate such promoters, and the bacterial promoter, rolC, was evaluated for tissue-specific expression in sugarcane.
Differential display is a non-directed technique that was used to identify genes that
are differentially expressed in the mature sugarcane culm. The original method was
modified, and four putative culm-preferential fragments were isolated. Sequence and
hybridisation analyses revealed that these fragments were false positives, and could therefore not be used to obtain a culm-specific promoter.
Activity of the Agrobacterium rolC promoter was evaluated by analysing expression
patterns of two reporter genes in the mature culm of transgenic sugarcane plants.
Nucleic acid analyses indicated that the foreign DNA was incorporated into the sugarcane genome, and that mRNA transcripts were produced. Histochemical
analysis was done to visualise rolC-driven GUS and GFP expression in the mature
sugarcane culm. In both cases the reporter gene expression was restricted to the vascular bundles and specifically to the phloem.
A directed approach was followed to isolate the gene and subsequently the promoter
of the β-subunit of pyrophosphate-dependent phosphofructokinase (PFP-β). An
incomplete cDNA clone was obtained from a mature culm cDNA library, and was
used for the screening of a sugarcane genomic library. Two clones containing
different parts of the PFP-β gene were isolated. A Deletion Factory™ system was
used to analyse the clone containing the 5' end of the gene. The first five exons and
1747 bp of the 5' flanking region of the gene were sequenced. Preliminary activity analysis of the promoter region was done by constructing two expression vectors, and analysing transient GUS expression in sugarcane callus. Results indicated that the promoter is capable of driving foreign gene expression in callus. Transient expression levels were lower than that of the maize Ubi-1 promoter. Further analysis of the 5' flanking region will be done to establish whether cis-acting elements outside
the analysed area have an influence on the activity of the promoter. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1997.
|
Page generated in 0.1146 seconds