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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.
71

Identification of variants within the coding region and 5'-flanking region of the k-casein encoding gene in Holsteins using PCR-RFLP and PCR-SSCP analyses

Masoudi, Mehrnoush January 1996 (has links)
Single-strand conformation polymorphism analysis (SSCP) and restriction fragment length polymorphism analysis (RFLP) were used to determine the genotype of Holsteins at the $ kappa$-casein ($ kappa$-CN) locus. A 432-bp fragment within exon IV containing nucleotide substitutions diagnostic of the A- and B-variants of $ kappa$-CN was amplified using the polymerase chain reaction (PCR). The sires from the earliest years of the AI industry had a significantly higher (p $<$ 0.01) frequency of allele than sires in modern usage. These data indicate that selection or milk production parameters may discriminate against the B-allele. SSCP analysis was also used for detecting polymorphisms within the regulatory region of $ kappa$-CN gene. A 640-bp fragment within the 5$ sp prime$-flanking region of bovine $ kappa$-CN gene which contained the TATA box, CAAT box, and exon I was amplified using PCR. The SSCP analysis of this fragment revealed no variation, possibly due to the lower detection efficiency of SSCP with large fragment size. Nested primers were, therefore, designed to amplify fragments of 234- and 486-bp. Polymorphism was detected only in the 486-bp fragment and the two variants were designated M$ sb1$ and M$ sb2.$ The allelic frequencies of M$ sb1$ and M$ sb2$ in bulls used by AI industry before 1970 were 0.67 and 0.33, and in bulls used by AI industry after 1980 the frequencies were 0.68 and 0.32, respectively. The frequency of these alleles were not significantly different in Holsteins used by AI industry before 1970 and after 1980. Unlike the apparent change in frequency of the A- and B-variants noted within exon IV, this polymorphism seems to have not responded to selection. However, a higher frequency of M$ sb1$ allele appeared to be associated with B-variant (exon IV) genotypes. The presence of these variants within the regulatory region may possibly be involved in the quantitative expression of $ kappa$-CN gene. (Abstract shortened by UMI.)
72

The effect of bovine casein peptides on cytokine and nitric oxide production by macrophages

Xiao, Chaowu, 1962- January 1996 (has links)
Three bovine casein peptides, LLY, PGPIPN, and TTMPLW, have been reported to stimulate phagocytosis of sheep red blood cells by murine macrophages. TTMPLW also protected mice against Klebsiella pneumoniae infection. The purpose of this study was to investigate the effects of these three peptides on cytokine (TNF-$ alpha$ and IL-6) production and nitric oxide (NO) release by bone marrow macrophages (BMM). The peptides alone were incapable of stimulating cytokine production or NO release in naive or IFN-$ gamma$-primed BMM. However, when BMM were coincubated with the peptides (1.0 $ mu$M) and LPS (100 ng/ml), an augmentative effect on TNF-$ alpha,$ IL-6 and NO production was observed. The peptides increased the response of BMM to stimulation with LPS in a dose- and time-dependent manner. Of the three peptides, TTMPLW (0.01, or 1.0 $ mu$M) had the greatest augmentative effect on NO production by LPS-stimulated BMM. Tumor necrosis factor-$ alpha$ production peaked after 4 hr stimulation, and decreased rapidly thereafter. Among three peptides, TTMPLW induced the highest amount of TNF-$ alpha$ production at a concentration of 1.0 $ mu$M. When used at a concentration as low as 0.01 $ mu$M, TTMPLW and PGPIPN, but not LLY, potentiated TNF-$ alpha$ production. All the peptides (1.0 $ mu$M) stimulated IL-6 production by BMM, which plateaued after 12 hr. The auto/paracrine TNF-$ alpha$ produced by LPS-stimulated BMM was partially responsible for release of NO. After all the TNF-$ alpha$ was neutralized, release of NO was reduced by about 21% (P $<$ 0.01). However, neutralization of IL-1$ beta$ and IL-6 did not have any effect on NO production by LPS-stimulated BMM. These results demonstrate that bovine casein peptides can costimulate naive macrophages with LPS for proinflammatory cytokine production and NO release and may play a role in host defense against pathogens.
73

Untersuchungen zur Hydrolyse von Beta-Casein in Modellsystemen und in ausgewählten Käsesorten

Koch, Juliane, January 2005 (has links)
Dresden, Techn. Univ., Diss., 2004.
74

The effect of salts on the parcasein-sodium hydronide [sic] equilibrium ...

Robinson, Allen Dinwoody, Gortner, Ross Aiken, Palmer, Leroy S., January 1900 (has links)
Thesis (Ph. D.)--University of Minnesota, 1930. / Cover title. Vita. Caption title: Physico-chemical studies on proteins. VI. The effect of salts on the casein-sodium hydroxide and paracasein-sodium hydroxide equilibria [by] Allen D. Robinson, Ross Aiken Gortner and Leroy S. Palmer. "Published as Paper no. 1087, Journal series, Minnesota Agricultural experiment station." From the Journal of physical chemistry, vol. XXXVI, no. 7, July, 1932. "Literature cited": p. 1881.
75

Milk production response to supplementation of encapsulated methionine per os or casein per abomasum

Broderick, Glen Allen, January 1970 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1970. / Typescript eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 62-74)
76

Regulation der clp-Genexpression durch ClgR und Definition des ClgR-Regulons aus Corynebacterium glutamicum

Engels, Sabine. Unknown Date (has links)
Universiẗat, Diss., 2004--Düsseldorf.
77

Creation of a sticky coating of dairy proteins containing bioactive peptides to reduce dental caries

Noren, Nancy Ellen 11 January 2016 (has links)
A sticky coating composed of dairy proteins and bioactive peptides (caseinophosphopeptides, CPPs) to prevent dental caries was formulated. The coating consisted of 10% CPPs, 70% glycerol and 20% casein (or hydrolysate) and/or whey in ratios from 0:100 to 100:0 casein:whey. Sodium caseinate was hydrolysed with three different enzymes, Alcalase, trypsin and α-chymotrypsin, yielding three hydrolysates classified as CN-A, CN-T and CN-C, respectively. The degree of hydrolysis reached levels of 18.04, 13.63 and 11.40% for CN-A, CN-T and CN-C respectively. Degree of hydrolysis was proportional to molecular weight determined by FPLC. CN-C coatings were the stickiest based on probe-tack test and capable of withstanding up to 22.46 N of force. Attempts to correlate glass transition temperatures to stickiness of the coatings proved inconclusive. All coatings were capable of binding enough calcium to remineralise tooth enamel. Results indicated that 100:0 CN-C:whey produced the stickiest coating; however this combination also increased bacterial adhesion. / February 2016
78

The adsorption of proteins onto ultrafiltration membranes

Ayre, Lorna M. January 2000 (has links)
The mass of five proteins (Bovine serum albumin (BSA), casein, lysozyme, ovalbumin and pepsin) adsorbed to five different membrane materials (of various hydrophobicities) was quantified using a static system and analysed to establish any trends. Comparing the results from the five membranes it seems that there were no obvious trends between the protein masses adsorbed indicating that it may not be just one aspect of protein structure that is important in the adsorption process. Many investigations have indicated that the protein may undergo a conformational change during the adsorption process. Disulphide bridges contribute readily to the stability of the protein molecule and it was hypothesised that if such a structural change occurred, it would result in the breakage of these covalent bonds. To this end, the free thiol group content of the proteins was quantified before and after adsorption.
79

Estudo da estabilidade da micela de caseina em leite estável e instável não ácido

Fortuna, Lelis Aparecida Petrini 16 March 2015 (has links)
O leite instável não ácido (LINA) caracteriza-se pela perda da estabilidade da caseína ao teste do etanol, sem apresentar acidez acima de 18 °D. Este tipo de leite não é transportado para a indústria devido à subjetividade e imprecisão do teste do etanol, o qual não diferencia os tipos de leite, sendo eles: leite normal, LINA e o leite ácido. Este trabalho teve como objetivo contribuir para a compreensão dos fenômenos físico-químicos envolvidos na estabilidade e instabilidade das micelas de caseína em LINA e leite estável bovino e, desenvolver testes alternativos para a identificação e diferenciação de leite estável, ácido e LINA. Para este estudo foram utilizadas 58 vacas da raça Jersey e 130 vacas da raça Holandês em lactação. Teste de mastite subclinica para os animais da raça Jersey revelou 67% de positividade. O principal agente microbiano isolado do leite foi o Staphylococcus coagulase positivo. Não foi evidenciada relação entre a mastite subclínica e o LINA. Os atributos químicos do leite apresentaram diferenças significativas entre as raças avaliadas, independente da estabilidade do leite. Animais com períodos de lactação mais longos apresentaram maior instabilidade da caseína independente da raça estudada. Quanto a acidez, pH, contagem de células somáticas e contagem de bactérias totais não houve diferenças significativas para a estabilidade e raças avaliadas. O LINA apresentou todos os parâmetros avaliados dentro dos padrões exigidos pela legislação brasileira e não apresentando variações significativas com o leite estável. Testes de estabilidade em distintas concentrações de etanol mostrou que 72% (v/v) de etanol diferenciam claramente leite estável e o LINA. Leite estável e LINA apresentaram estabilidade térmica, mostrando que os dois testes não estão correlacionados. O perfil eletroforético das proteínas de leite estável e LINA não apresentou diferenças evidentes, indicando que a instabilidade não está associada a modificações qualitativas ou quantitativas nas caseínas do leite. Os resultados da análise de cálcio e fósforo total, micelar e solúvel, indicaram que o teor de cálcio na fração solúvel é consideravelmente maior no LINA, evidenciando que o cálcio iônico pode ser um fator importante na estabilidade do leite. Além disso, a relação Ca/P foi de 1,1/1 e 1,6/1 em leite estável e LINA, respectivamente. O maior teor de cálcio em relação ao fósforo no LINA pode contribuir para a sua desestabilização da micela de caseína na presença de etanol. O presente estudo deu origem a uma patente de invenção e sistema logístico para coleta de leite, a fim de evitar desperdícios indevidos e interpretações equivocadas acerca do tipo de leite. Particularmente, os métodos patenteados permitem que sejam realizados testes em campo que identificam e diferenciam de forma rápida e eficiente as amostras de leite estável, LINA e leite ácido. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-07-15T18:53:51Z No. of bitstreams: 1 Tese Lelis Aparecida Petrini Fontoura.pdf: 162872 bytes, checksum: ba234bd6702c33d0a239b0d5b99ca17b (MD5) / Made available in DSpace on 2015-07-15T18:53:51Z (GMT). No. of bitstreams: 1 Tese Lelis Aparecida Petrini Fontoura.pdf: 162872 bytes, checksum: ba234bd6702c33d0a239b0d5b99ca17b (MD5) / Universidade de Caxias do Sul, UCS. / The unstable non-acid milk (UNAM) is characterized by the instability of caseins in the ethanol test and low acidity (≤ 18 °D). This kind of milk is not transported to the industry due to the subjectivity and low precision of the ethanol test, which is not able to differenciate normal (stable), UNAM, and acid milk. The objective of the present work was to contribute for the understanding of the physic-chemical fenomena involved in the stability and instability of the casein micela in UNAM and stable bovine milk, and to develop reliable tests for the identification and diferenciation of stable, unstable, and acid milks. This study included 58 Jersey and 130 Holland cows in lactation. The subclinical mastitis test of Jersey animals resulted in 67% positivity. The most prevalent microbial agent isolated from subclinical mastitis milks was coagulase-positive staphylococci. It was not evidence any relation between subclinical mastitis and UNAM. Significant differences were detected between Jersey and Holland milks, but these were not related with milk stability. Animals with longer lactation period showed highest frequency of UNAM, independent of cow´s race. No significant differences for pH, acidity, somatic cell count, and total bacterial count, were detected between races and stable milk and UNAM. The UNAM showed all the parameter within the patterns stablished by Brazilian legislation, with not significant differences from stable milks. Stability tests in different ethanol concentrations showed that 72% (v/v) ethanol clarely discriminated UNAM and stable milk. Both UNAM and stable milk exhibited the same behavior at high temperatures, indicating that ethanol and thermal stability are not correlated. No differences were detected between the protein electrophoretic profile of stable milk and UNAM, indicating that the instability is not associated with qualitative or quantitative modification of milk caseins. The analysis of total, micelial and soluble calcium and phosphorus showed that calcium concentration in the soluble fraction is higher in UNAM than in stable milk, indicating that ionic calcium can be an important factor in milk stability. Moreover, Ca/P relation was 1.1/1 and 1.6/1 in stable milk and UNAM, respectively. The highest Ca/P relation in UNAM can contribute for the destabilization of the casein micela in the presence of ethanol. The present study originates an invention patent for the evaluation of milk stability, and a logical system for milk transport, that can reduce losses by the correct determination of milk quality. The patented method allows the rapid and efficient identification and differenciation of stable, UNAM and acid mik in the rural property and industry.
80

Estudo da estabilidade da micela de caseina em leite estável e instável não ácido

Fortuna, Lelis Aparecida Petrini 16 March 2015 (has links)
O leite instável não ácido (LINA) caracteriza-se pela perda da estabilidade da caseína ao teste do etanol, sem apresentar acidez acima de 18 °D. Este tipo de leite não é transportado para a indústria devido à subjetividade e imprecisão do teste do etanol, o qual não diferencia os tipos de leite, sendo eles: leite normal, LINA e o leite ácido. Este trabalho teve como objetivo contribuir para a compreensão dos fenômenos físico-químicos envolvidos na estabilidade e instabilidade das micelas de caseína em LINA e leite estável bovino e, desenvolver testes alternativos para a identificação e diferenciação de leite estável, ácido e LINA. Para este estudo foram utilizadas 58 vacas da raça Jersey e 130 vacas da raça Holandês em lactação. Teste de mastite subclinica para os animais da raça Jersey revelou 67% de positividade. O principal agente microbiano isolado do leite foi o Staphylococcus coagulase positivo. Não foi evidenciada relação entre a mastite subclínica e o LINA. Os atributos químicos do leite apresentaram diferenças significativas entre as raças avaliadas, independente da estabilidade do leite. Animais com períodos de lactação mais longos apresentaram maior instabilidade da caseína independente da raça estudada. Quanto a acidez, pH, contagem de células somáticas e contagem de bactérias totais não houve diferenças significativas para a estabilidade e raças avaliadas. O LINA apresentou todos os parâmetros avaliados dentro dos padrões exigidos pela legislação brasileira e não apresentando variações significativas com o leite estável. Testes de estabilidade em distintas concentrações de etanol mostrou que 72% (v/v) de etanol diferenciam claramente leite estável e o LINA. Leite estável e LINA apresentaram estabilidade térmica, mostrando que os dois testes não estão correlacionados. O perfil eletroforético das proteínas de leite estável e LINA não apresentou diferenças evidentes, indicando que a instabilidade não está associada a modificações qualitativas ou quantitativas nas caseínas do leite. Os resultados da análise de cálcio e fósforo total, micelar e solúvel, indicaram que o teor de cálcio na fração solúvel é consideravelmente maior no LINA, evidenciando que o cálcio iônico pode ser um fator importante na estabilidade do leite. Além disso, a relação Ca/P foi de 1,1/1 e 1,6/1 em leite estável e LINA, respectivamente. O maior teor de cálcio em relação ao fósforo no LINA pode contribuir para a sua desestabilização da micela de caseína na presença de etanol. O presente estudo deu origem a uma patente de invenção e sistema logístico para coleta de leite, a fim de evitar desperdícios indevidos e interpretações equivocadas acerca do tipo de leite. Particularmente, os métodos patenteados permitem que sejam realizados testes em campo que identificam e diferenciam de forma rápida e eficiente as amostras de leite estável, LINA e leite ácido. / Universidade de Caxias do Sul, UCS. / The unstable non-acid milk (UNAM) is characterized by the instability of caseins in the ethanol test and low acidity (≤ 18 °D). This kind of milk is not transported to the industry due to the subjectivity and low precision of the ethanol test, which is not able to differenciate normal (stable), UNAM, and acid milk. The objective of the present work was to contribute for the understanding of the physic-chemical fenomena involved in the stability and instability of the casein micela in UNAM and stable bovine milk, and to develop reliable tests for the identification and diferenciation of stable, unstable, and acid milks. This study included 58 Jersey and 130 Holland cows in lactation. The subclinical mastitis test of Jersey animals resulted in 67% positivity. The most prevalent microbial agent isolated from subclinical mastitis milks was coagulase-positive staphylococci. It was not evidence any relation between subclinical mastitis and UNAM. Significant differences were detected between Jersey and Holland milks, but these were not related with milk stability. Animals with longer lactation period showed highest frequency of UNAM, independent of cow´s race. No significant differences for pH, acidity, somatic cell count, and total bacterial count, were detected between races and stable milk and UNAM. The UNAM showed all the parameter within the patterns stablished by Brazilian legislation, with not significant differences from stable milks. Stability tests in different ethanol concentrations showed that 72% (v/v) ethanol clarely discriminated UNAM and stable milk. Both UNAM and stable milk exhibited the same behavior at high temperatures, indicating that ethanol and thermal stability are not correlated. No differences were detected between the protein electrophoretic profile of stable milk and UNAM, indicating that the instability is not associated with qualitative or quantitative modification of milk caseins. The analysis of total, micelial and soluble calcium and phosphorus showed that calcium concentration in the soluble fraction is higher in UNAM than in stable milk, indicating that ionic calcium can be an important factor in milk stability. Moreover, Ca/P relation was 1.1/1 and 1.6/1 in stable milk and UNAM, respectively. The highest Ca/P relation in UNAM can contribute for the destabilization of the casein micela in the presence of ethanol. The present study originates an invention patent for the evaluation of milk stability, and a logical system for milk transport, that can reduce losses by the correct determination of milk quality. The patented method allows the rapid and efficient identification and differenciation of stable, UNAM and acid mik in the rural property and industry.

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