• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 74
  • 39
  • 19
  • 14
  • 6
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 188
  • 34
  • 29
  • 20
  • 17
  • 16
  • 15
  • 14
  • 13
  • 12
  • 11
  • 10
  • 10
  • 9
  • 9
  • 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.
61

Effect of dietary polyunsaturated fatty acid and related nutrients on plasma lipids, and skin and hair coat condition in canines

Hester, Shaleah Lynnae 15 November 2004 (has links)
A study was performed to investigate the effect of diet modifications on skin and hair coat condition in canines. The study included 24 normal adult dogs fed a baseline diet (Ol'Roy[trademark]), during an acclimation period of 12 wk (Phase I). Nine female Beagles and 15 male Hound mix-breed dogs were used. For the next 12 wk (Phase II) the dogs were divided into three groups and fed one of three specially formulated diets. They contained similar ingredients and had similar nutrient profiles except for the following differences: Diet A contained lower but adequate amounts of dietary zinc and linoleic acid than diet B. Diet C was similar to B with respect to zinc and linoleic acid but contained more α-linolenic acid. An evaluation panel conducted skin and hair coat condition scoring on wk 0, 4, 7, and 12 (Phase I) and wk 14, 16, 19, and 24 (Phase II). The panel evaluated the dogs for glossiness, softness, scale, greasiness, and overall condition. Transepidermal water loss (TEWL) and skin hydration (HYDR) assessments were determined on wk 3, 7, and 11 (Phase I) and wk 11, 12, 15, 19, and 23 (Phase II) using a Tewameter[trademark] and Corneometer[trademark] respectively. Blood samples were collected on d 0, 5, 8, 16, 28, 56, and 84. Profiles of plasma phospholipid fatty acids were determined at each collection period. Serum zinc concentrations were analyzed on wk 12, 14, and 24. The hypothesis was that a diet containing increased LA, ALA, and zinc concentrations (diet C) would show improvements of skin and hair coat condition in dogs compared to the other diets. All three test diets caused significant improvements compared to Ol'Roy[trademark]. Diet B caused more improvement than diet A in both subjective and objective assessments of skin and hair coat. Based on mean values diet B is better to be fed to dogs that need to improve skin hydration and diet C should be fed to dogs that need to decrease TEWL. Diet C not only led to improvements in skin and hair coat condition, but also provided additional benefit by producing less pro-inflammatory conditions in the skin.
62

A Preliminary Study of Bacillus licheniformis Spore Coat Proteins Detection by Surface Plasmon Resonance

Fung, Kok Wai January 2015 (has links)
Food poisoning is mainly caused by pathogenic microorganisms and is now a severe problem worldwide. Therefore, rapid and sensitive methods are required to detect foodborne pathogens. A locally isolated bacterium, Bacillus licheniformis B38 was selected for this study. The spores of B. licheniformis B38 were induced by Schaeffer’s sporulation medium containing KCl, MgSO4.7H2O, Ca(NO3)4, MnCl2 and FeSO4. Schaeffer-Fulton endospore staining was used to differentiate spores and vegetative cells, where spores were stained green and vegetative cells were stained red. In order to separate the spores from the cells, a two-phase system was used to obtain pure spore suspension for following experiments. Spore coat proteins were extracted by SDS-8 M urea sample buffer and visualized by two different types of coomassie brilliant blue staining solutions. One of the staining solutions was more suitable for gel elution by diffusion. An ~10 kDa spore coat protein was selected for protein purification. Based on the given results, the protein purification by liquid chromatography was less convincing than using gel elution by diffusion technique. The two hypothetical protein sequences, P06552 and P45693, from the ~10 kDa spore coat protein were identified. In the preliminary study of B. licheniformis B38 spores detection by surface plasmon resonance, several binding parameters were studied. Dot blot was done to verify the reaction between the Bacillus spores polyclonal antibody against the B. licheniformis B38 spore coat protein. The most promising result was the binding of 0.1 mg/mL polyclonal antibody (analyte) to the 0.2 mg/mL spore coat protein at pH 2 (ligand) which showed 5.74 RU. The differences between a dot blot and a SPR detection techniques are described.
63

Single and Mixed Infections of Plant RNA and DNA Viruses are Prevalent in Commercial Sweet Potato in Honduras and Guatemala

Avelar, Ana Sofia January 2015 (has links)
Sweet potato is one of the 15 most important food crops worldwide. At least 30 different virus species, belonging to different taxonomic groups affect sweet potato. Little is known about the viruses present in sweet potato crops in Central America, which is the primary origin of sweet potato. The objective of this study was to design and implement primers for use in polymerase chain reaction (PCR) and Reverse transcription-PCR (RT-PCR) to identify and survey the diversity of plant viruses infecting sweet potato in Honduras and Guatemala. Primers were designed and used to amplify, clone, and sequence a taxonomically informative fragment of the coat protein (CP) gene for whitefly-transmitted geminiviruses (herein, sweepoviruses) and potyviruses, and of the heat shock protein 70 (HSP70) for the Crinivirus, Sweet potato chlorotic stunt virus (SPCSV). The partial genome sequences were used for identification based on phylogenetic relationships with reference sequences available in the GenBank database. All three of the plant virus groups identified in this study were found to occur either in single or in multiple infections. Results of the sequence analyses indicated that the genomic regions amplified in this study were capable of discriminating among potyvirus species, and strains of SPCSV. With respect to potyvirus, all isolates were identified as Sweet potato feathery mottle virus (SPFMV) species, except for two, which grouped phylogenetically with Sweet potato virus G (SPVG) and Sweet potato virus C (SPVC). All sweepoviruses detected in sweet potato plants belonged to a single phylogenetically, well-supported group that contains all other previously described geminiviruses (sweepoviruses) associated with sweet potato or closely related host species. These results demonstrate that the primers designed for amplification of plant virus species commonly recognized to infect sweet potato, effectively detected the viruses singly and in mixtures from symptomatic plants, and that the resultant fragment, when subjected to cloning and DNA sequenced, was phylogenetically informative at the species and/or strain levels, depending on the virus group.
64

Genų, atsakingų už spalvos paveldėjimą, tyrimas arklių genome / Investigations of Investigations of genes responsible for coat color inheritance in horses genome

Butavičiūtė, Inga 19 April 2007 (has links)
Object and tasks of work: 1. Analyse and summarize literature about horse coat color and it genetic background. 2. Perform phenotypical analysis of Lithuanian Heavy Darught horse coat color polymorphism. 3. Introduce horse MC1R gene research methodology at K. Janušauskas Laboratory of Animal Genetics, LVA. 4. Investigate MC1R gene polymorphism and distribution of different alleles at Lithuanian heavy draught by PCR-RFLP method. 5. Determine correlation between restriction fragment lenght polymorphism (RFLP) in MC1R gene and horse bay coat color polymorhism. Research methodology: 1. DNA extraction from hair roots. 2. PCR to amplify MC1R gene. 3. RFLP method-MC1R – enzyme Tag I. 3. Electrophoresis in agarose gel. 4. Staining with Etidium bromide. 5. Genotyping. 6. Stasitical analysis of data. Results and conclutions: The following DNA restriction fragments were obtained for the MC1R – Tag I polymorphism: PCR product - 460 bp; genotypes E/E; ea/ea – 460 bp; genotypes e/e – 275 bp; 185 bp; genotypes E/e; e/ea – 460 bp; 275 bp; 185 bp. After phenotypical investigation of coat color from 32 Lithuanian Heavy draught horses following variation have been found: light bay, bay, dark bay, roan and chesnut. Light bay horses with different intensivity of coat color comprised 84,4 %. From total investigated animals 34.4 % had e/e genotype, E/e – 12.5 %, e/ea - 50 % and E/E genotype – 3.1 %. Two different genotypes e/e (40.7 %) and e/ea (59.3) were found among bay color horses... [to full text]
65

Development of molecular markers for marker assisted selection for seed quality traits in oilseed rape

Rahman, Md. Mukhlesur 28 September 2007 (has links)
Molecular markers for seed quality traits including erucic acid content genes, seed coat color genes in Brassica napus and seed coat color genes in B. rapa were developed. A single base change in the Bn-FAE1.1 gene in the A genome and a two-base deletion in the Bn-FAE1.2 gene in the C genome produce the nearly zero content of erucic acid observed in canola. The single base change was detected as single nucleotide polymorphic (SNP) marker with an ABI SNaPshot kit. A multiplexing primer set was designed by adding a polyT to the 5´ primer end to increase SNP detection throughput through sample pooling. The two-base deletion in the C genome gene was detected as a sequence characterized amplified region (SCAR) marker in an ABI 3100 Genetic analyzer. To increase the throughput, one genome specific primer was labeled with four fluorescence dyes and combined with 20 different primers to produce PCR products with different fragment sizes. These multiplexed high throughput molecular markers have been successfully implemented in our canola/rapeseed breeding programs. Trigenic inheritance was observed for seed coat color in B. napus. Three Sequenced Related Amplified Polymorphism (SRAP) markers very closely linked to the three different seed coat color genes were developed. Chromosome-walking technology was used to convert the SRAP marker into a SCAR marker and a SNP marker. Subsequently, the first seed coat color gene (Bn1) marker was converted into a SCAR marker, and the second seed coat color gene (Bn2) marker was converted into a SNP marker. Digenic inheritance was observed for seed coat color genes in B. rapa. A SRAP marker was identified as being tightly linked to the major seed coat color gene (Br1). The SRAP marker was sequenced and extended sequences were obtained using chromosome-walking technology. The flanking sequences of the SRAP marker contained 24 SNPs and a 12-bp deletion position that allowed the marker to be converted into a co-dominant SNP marker and a co-dominant SCAR marker, respectively. The SCAR marker was detected in the ABI 3100 genetic analyzer with four fluorescently labeled M13 primers integrated with different SCAR primers, which permitted pooling of PCR samples for high throughput detection.
66

PERFORMANCE AND PHYSIOLOGY OF YEARLING STEERS GRAZING TOXIC TALL FESCUE AS INFLUENCED BY CONCENTRATE FEEDING AND STEROIDAL IMPLANTS

Carter, Jessica Meagan 01 January 2008 (has links)
Fescue toxicosis can produce negative effects on animal weight gain and physiology. Sixty-four steers were grazed on endophyte-infected (E+) KY-31 tall fescue for 77 days in 2007 and sixty steers grazed for 86 days in 2008 to evaluate interactions with implantation of steroidal implants and concentrate feeding on performance and physiology of yearling steers. Steers were stratified by body weight for assignment to six, 3.0-ha toxic tall fescue pastures. The main plot treatment of with or without pelleted soybean hulls (SBH) were randomly assigned to pastures. Pelleted SBH were group-fed to provide daily consumptions of 2.3 kg/steer/d (as fed). Sub-plot treatments of with or without ear implantation with steroid hormone (200 mg progesterone--20 mg estradiol were assigned to groups of five or six steers within each pasture. Average daily gain in the experiment showed an additive effect of feeding SBH and implanting (P
67

Development of molecular markers for marker assisted selection for seed quality traits in oilseed rape

Rahman, Md. Mukhlesur 28 September 2007 (has links)
Molecular markers for seed quality traits including erucic acid content genes, seed coat color genes in Brassica napus and seed coat color genes in B. rapa were developed. A single base change in the Bn-FAE1.1 gene in the A genome and a two-base deletion in the Bn-FAE1.2 gene in the C genome produce the nearly zero content of erucic acid observed in canola. The single base change was detected as single nucleotide polymorphic (SNP) marker with an ABI SNaPshot kit. A multiplexing primer set was designed by adding a polyT to the 5´ primer end to increase SNP detection throughput through sample pooling. The two-base deletion in the C genome gene was detected as a sequence characterized amplified region (SCAR) marker in an ABI 3100 Genetic analyzer. To increase the throughput, one genome specific primer was labeled with four fluorescence dyes and combined with 20 different primers to produce PCR products with different fragment sizes. These multiplexed high throughput molecular markers have been successfully implemented in our canola/rapeseed breeding programs. Trigenic inheritance was observed for seed coat color in B. napus. Three Sequenced Related Amplified Polymorphism (SRAP) markers very closely linked to the three different seed coat color genes were developed. Chromosome-walking technology was used to convert the SRAP marker into a SCAR marker and a SNP marker. Subsequently, the first seed coat color gene (Bn1) marker was converted into a SCAR marker, and the second seed coat color gene (Bn2) marker was converted into a SNP marker. Digenic inheritance was observed for seed coat color genes in B. rapa. A SRAP marker was identified as being tightly linked to the major seed coat color gene (Br1). The SRAP marker was sequenced and extended sequences were obtained using chromosome-walking technology. The flanking sequences of the SRAP marker contained 24 SNPs and a 12-bp deletion position that allowed the marker to be converted into a co-dominant SNP marker and a co-dominant SCAR marker, respectively. The SCAR marker was detected in the ABI 3100 genetic analyzer with four fluorescently labeled M13 primers integrated with different SCAR primers, which permitted pooling of PCR samples for high throughput detection.
68

Chicken Eggshell Membrane and Cuticle: Insight from Bioinformatics and Proteomics

Du, Jingwen 10 January 2013 (has links)
The chicken eggshell possesses physical and chemical barriers to protect the embryo from pathogens. The avian eggshell cuticle is the outmost layer of the eggshell whose protein constituents remain largely unknown. Since eggs with incomplete or absent cuticle are more susceptible to bacterial contamination, we hypothesize that cuticle protein components play an important role in microbial resistance. In our study, at least 47 proteins were identified by LC/MS/MS in the non-calcified cuticle layer. Similar to Kunitz-like protease inhibitor (also annotated as ovocalyxin-25, OCX-25) and ovocalyxin-32 (OCX-32) were two of most abundant proteins of the cuticle proteins. Some proteins that have antimicrobial activity were also detected in the proteomic results, such as lysozyme C, ovotransferrin, ovocalyxin-32, cystatin, ovoinhibitor. This study represents the first comprehensive report of the cuticle proteome. Since the sequence similarity of the kunitz motif in OCX-25 is similar to that of BPTI, it is predicted that it will have the same trypsin inhibitory and antimicrobial activity against Gram-positive and/or Gram-negative bacteria. In order to test the antimicrobial property and trypsin inhibitor activity of OCX-25, cuticle proteins were extracted by 1N HCl. Antimicrobial activity was monitored using the Bioscreen C instrument; and antimicrobial activity was identified primarily against Staphylococcus aureus. Trypsin inhibitor activity was studied by using a specific trypsin assay, and the assay indicated that the cuticle proteins could inhibit the reaction of trypsin and substrate. Therefore, the current research has provided some insight into the antimicrobial and enzymatic aspects of the cuticle proteins, and its function for egg protection. Eggshell membranes are another important component of the chicken eggshell.Due to its insoluble and stable properties, there are still many questions regarding formation and constituents of the eggshell membranes. The purpose of our study was to identify eggshell membrane proteins, particularly these responsible for its structural features, by examining the transcriptome of the white isthmus during its formation. Bioinformatics tools were applied to analyze the differentially expressed genes as well as their encoded proteins. Some interesting proteins were encoded by the over-expressed genes in the white isthmus during the formation of eggshell membranes, such as Collagen X, and similar to spore coat protein SP75. These proteins may have potential applications. Our study provides a detailed description of the chicken white isthmus transcriptome during formation of the eggshell membranes; it could lead to develop the strategies to improve food safety of the table egg.
69

Probing the structure of the pericellular matrix via novel biophysical assays

McLane, Louis T. 12 January 2015 (has links)
The pericellular matrix (PCM) is a voluminous polymer network adhered to and surrounding many different types of mammalian cells, and which extends out into the environment outside the cell for distances ranging up to twenty microns. It is comprised of very long flexible polymers (hyaluronan) which are tethered to the cell surface and which have binding sites for large, highly charged bottle brush proteoglycans (aggrecan). The PCM plays an important role in many cell functions such as cell proliferation, cell adhesion, cell migration, and cancer development, however the precise way it influences these processes remains unclear. Three original biophysical tools are developed in this thesis in order to study the PCM: the quantitative particle exclusion assay (qPEA), optical force probe assay (OFPA), and exogenous fluorescent aggrecan mapping assays. These tools are used to measure the polymeric and biophysical properties of the matrix in order to make further advancements in the understanding the PCMs role in adhesion, transport to and from the cell surface, its purported function as a chemical micro-reservoir, as well as basic studies on the kinetics of its formation, turnover and maintenance. The qPEAs measure the penetration and distribution of sub-micron particles after they diffuse into the cell coat, where their distribution maps the interior structure of the PCM. The qPEA assays reveal that the PCM acts a sieve, separating incoming particles by their size, preventing micron sized particles from entering the PCM while allowing sub 100 nm particles to pass to the cell surface. The OFPA uses an optically-trapped bead to study the force response of the matrix as it encounters the probe. The assay not only reveals new details about the PCM such as the fact that it is larger than initially thought, having a two layer structure, but when combined with a polymer physics model which relates the observed equilibrium forces to an existing osmotic pressure gradient within the PCM, the OFPA studies produce the first discovery and measurement of the correlation length distribution in the cell coat. The OFPA and qPEA assays are also performed on cells modified with exogenous aggrecan, resulting in a model for possible proteoglycan mediated cell coat transformations. The fluorescent exogenous aggrecan assays measure the dynamics of the exogenous aggrecan binding to and releasing from the coat, revealing that the PCM can be rapidly modified by a changing environment, and quantitatively measure how the exogenous aggrecan modifies the existing PCM. Together, these assays provide an unprecedented look into the interior structure of the PCM, and the mechanisms responsible both for this structure and its modification.
70

The cavin proteins as regulators of caveola formation and function

Michele Bastiani Unknown Date (has links)
Caveolae are small plasma membrane invaginations present in many different cell types, which have been linked to diverse cellular functions, including cell signalling, membrane rearrangements and lipid regulation. The caveolae markers, members of the caveolin family of proteins, are essential for caveola formation and function. Recently, however, a protein named PTRF (Polymerase I and Transcript Release Factor) or cavin, originally identified as a nuclear factor that regulates transcription in vitro, was shown to be associated with caveolae in adipocytes. In the first chapter of this thesis, I have used the zebrafish Danio rerio to investigate the relation of PTRF/cavin to caveolae as well as caveola function in vivo. During zebrafish development, PTRF/cavin was highly expressed in the notochord in 18 h, 24 h and 35 h post-fertilization embryos, as detected by in situ hybrydization. Analysis of later development stages showed that PTRF/cavin is also present in the otic vesicle, brachial arches, and periderm. Disruption of PTRF/cavin expression, via morpholino-mediated inhibition, caused severely defective development of the notochord as well as heart edema, in a dose-dependent manner. PTRF/cavin knockdown embryos had curved notochords and were shorter than the controls. Examination of the notochord by electron microscopy showed that the number of caveolae was greatly reduced in PTRF/cavin-morpholino-injected embryos. Similar effects were observed when caveolin-1, the major protein of caveolae in non-muscle cells, was down-regulated. Altogether, these results indicated a role for PTRF/cavin during formation and/or stabilization of caveolae as well as an essential role for caveolae during zebrafish embryo development. Combined with results obtained in mammalian cells, these findings identify PTRF/cavin as the first component of a caveolar coat, required for caveola formation and function (Hill et al., 2008). We subsequently identified a family of PTRF/cavin-related proteins, the cavins, that all associate with caveolae. Using biochemistry, light microscopy, and FRET-based approaches we characterised PTRF/cavin and the new members of this family of proteins SDR/cavin-2, SRBC/cavin-3 and MURC/cavin-4. We have shown that the four members of the cavin family form a multi-protein complex that associates with caveolae. This complex can constitutively assemble in the cytosol and then associate with caveolin at the plasma membrane caveolae; interestingly, caveolin is essential for the plasma membrane translocation of the cavin complex, and in caveolin-1 knockout cells the four cavin proteins are restricted to the cytosol. PTRF/cavin-1, but not other cavins, can induce caveola formation in a heterologous system and is required for the recruitment of the cavin complex to caveolae. The four cavin proteins present distinct patterns of tissue expression, which suggests that caveolae may perform tissue-specific functions regulated by the composition of the cavin complex. MURC/cavin-4 is expressed predominantly in muscle and its distribution is perturbed in human muscle disease associated with caveolin-3 dysfunction, identifying MURC/cavin-4 as a novel muscle disease candidate caveolar protein. To functionally investigate the relation of cavins and caveolae, we explored a caveolar function in mechanosensation. Through the use of hypo-osmotic media, we induced membrane-stretch and showed that the increased membrane tension leads to dissociation of the caveolin-cavin module and caveola disassembly as observed by immunofluorescence and FLIM/FRET techniques. Once released from caveolae, caveolin was seen internalized in late endosomes and lysosomes. Cavin-1, on the other hand, was found to be diffused in the cytosol and from there it was translocated to the nuclear compartment. The nuclear translocation was observed in several different cell types, which suggests a universal role for nuclear cavin-1, and was independent of caveolin expression. Analysis of live cells using real-time FLIM/FRET showed that cells quickly respond to variations in membrane tension by dissociation/re-association of caveolin and cavin-1. Altogether, in the course of this project, I was able to show that cavin-1 is an essential regulator of caveola biogenesis in cultured cells and in vivo. Cavin-1 and the other members of the PTRF/Cavin family form a multiprotein complex that is recruited to caveolae by caveolin and coats plasma membrane caveolae. The association between cavin-1 and caveolin is crucial for caveolae assembly and this interaction has a role in the cellular sensation of plasma membrane tension. Under high membrane tensions, caveolin and cavin-1 dissociate with the consequent flattening of caveolae. Under these circumstances, caveolin is internalized into enlarged endosomes and lysosomes while cavin-1 is translocated to the nucleus, identifying for the first time a caveola- to nucleus signalling pathway. The exact role of nuclear cavin-1 under plasma membrane stretch is now amenable to analysis.

Page generated in 0.028 seconds