In this study, four experiments were conducted to investigate the effect of inclusion level of dry distillers grains plus solubles (DDGS) or modified wet distillers grains plus solubles (MWDGS) (0, 16.7, 33.3, and 50% of ration DM) on performance, carcass characteristics, feeding behaviour, nutrient balance, nutrient excretion, and enzymatic activity using whole corn grain-based finishing diets. In experiment one, there were no effects (P > 0.05) of dietary treatment on final BW, ADG, days on feed, rumen pH at slaughter, dressing %, hot carcass weight, marbling score, lean yield, and lean color. Liver abscess score was lower in steers fed DGS than steers fed the control. Visits of cattle to the feeder (VF) increased when cattle were fed up to 16.7% of DDGS or 33.3% of MWDSG. Number of meals (NM) and eating rate (ER) was greater and time per meal (TM) was lower in cattle fed MWDGS compared to those fed DDGS. Also, increasing the distillers grains plus soluble (DGS) increased daily time at feeder (TF); however, ER decreased when cattle were fed up to33.3% of DGS and after that increased. In experiment two, total tract DM, OM, and starch digestibility decreased with increasing DDGS up to 50%. Daily intake and total excretion of N, P, S, Mg, and K increased linearly with increasing level of DDGS. Nitrogen retention did not change with level of DDGS; however, P retention tended to increase and S retention increased with increasing DDGS. The digestion and retention of Se, Mg, K, and Na did not differ among the treatments. In experiment three, although the pancreatic protein concentration (mg/g) increased linearly with increasing DGS levels, pancreatic mass (g and g/kg BW) did not change. Feeding DGS increased the pancreatic concentration of α-amylase and trypsin activity (U/g) compared to the control diet. Increasing the DGS level increased pancreatic concentration of trypsin activity (U/g). In experiment four, increasing DGS linearly increased kidney weight (g). Hepatic and renal glutathione peroxidases (GPX) activity was not influenced by inclusion level or form of DGS. However, renal GPX activity per kilogram of BW was affected by the form and linear effect interaction. Increasing inclusion level of DGS linearly increased carbamoyl phosphate synthetase (CPS) activity (kU/liver, and U/kg of BW), argininosuccinate synthetase (AS) and ornithine transcarbamoylase (OTC) activity (U/g, kU/liver, and U/kg of BW).The results of these studies suggest that feeding DDGS or MWDGS up to 50% diet DM in whole corn grain-based finishing diets does not negatively affect animal performance, although animals appear to adapt by altering feeding behaviour and nutrient metabolism. However, environmental implications of manure should be considered in the feedlot. / Beef Cattle Research Council, and Ontario Ministry of Agriculture Food and Rural Affairs

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 6 uppsatser.

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Andrea Krejzová Supervisor: PharmDr. Ivan Vokřál, Ph.D. Title of diploma thesis: Effect of albendazole on the activity of selected enzymes in tapeworm Hymenolepis diminuta The efficacy of anthelmintics used to treat diseases caused by helminths is not always sufficient, and in some cases, we are directly facing resistance to these drugs. Helminths, including tapeworms, are able to defend against the toxic effect of anthelmintics using several mechanisms. Xenobiotic metabolizing enzymes and transport proteins belong to these mechanisms. When xenobiotic metabolizing enzymes are induced, the efficacy of therapy may be significantly reduced. The effect of xenobiotic metabolizing enzymes on the drug resistance development has been already described in number of helminths. In tapeworms this information is still missing. Main aim of this study was to determine effect of drug albendazole on the activity of selected xenobiotic metabolizing enzymes in rat tapeworm (Hymenolepis diminuta). Tapeworms were incubated with albendazole (1 μM and 10 μM) for 24 hours. Then activities of selected enzymes in cytosol-like, microsome-like and mitochondria-like fractions were determined. This study is focused on...

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Karolína Lukačiková Supervisor: PharmDr. Ivan Vokřál, Ph.D. Title of diploma thesis: Effect of mebendazole on the activity of selected enzymes in tapeworm Hymenolepis diminuta The resistance of parasitic helminths to anthelmintic drugs is a growing worldwide phenomenon and a concerning issue. Xenobiotic metabolizing enzymes play an important role in drug resistance development as they can lower the concentration of the anthelmintics in the parasite's body and therefore protect the parasite from the anthelmintic effect. The role of drug metabolizing enzymes in drug resistance development has been already described in the group of roundworms and flukes. Limited information is available about this topic in tapeworms. In our study we decided to test the possibility of the anthelmintic mebendazole to affect the activity of these enzymes and possibly to influence the drug resistance development in rat tapeworm (Hymenolepis diminuta). Our first goal was the isolation of adult tapeworms from the definitive host (rat, Rattus norvegicus). We used mealworm beetle (Tenebrio molitor) as an intermediate host. After the successful isolation, adult tapeworms were incubated with the mebendazole (1 and 10µM) in...

Made available in DSpace on 2014-10-09T12:27:17Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:13Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:27:17Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:13Z (GMT). No. of bitstreams: 0 / A giroxina é uma enzima serinoprotease do veneno da cascavel sul-americana Crotalus durissus terrificus. É uma toxina apenas parcialmente caracterizada e com múltiplas atividades. Atua na coagulação, na diminuição da pressão arterial e induz um comportamento neurotóxico descrito como rolamento em barril. Os mecanismos envolvidos nestas atividades não são conhecidos. Considerando que a giroxina é uma enzima com alto potencial para ser um novo fármaco com aplicações em clínica médica como a trombina, tripsina, ancrod®, batroxobin® e calicreína, é importante determinar como a giroxina atua. As análises em eletroforese em gel de poliacrilamida e dicroísmo circular confirmaram a pureza e integridade da molécula. A administração intravenosa em camundongos comprovou a neurotoxicidade (rolamento em barril). O estudo in vivo com microscopia intravital comprovou que a giroxina induz vasodilatação com participação dos receptores ativados por proteases (PARs), do óxido nítrico e da Na+K+ATPase. A adesão e rolamento de leucócitos indicaram que não possui atividade pró-inflamatória. A giroxina induziu a agregação plaquetária, que foi bloqueada pelos inibidores dos receptores PAR-1 e PAR-4 (SCH 79797 e tcY-NH2, respectivamente). Finalmente, foi demonstrado que a giroxina alterou temporariamente a permeabilidade da barreira hematoencefálica (BHE). Neste estudo foi comprovado que os receptores ativados por proteases e o óxido nítrico são mediadores envolvidos nas atividades biológicas da giroxina. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

No description available.

Enzymes react quickly to environmental stress and can serve as sensitive indicators of environmental change. Microbial enzyme activities (MEA’s) can be a useful tool to evaluate the health of an aquatic ecosystem. In this study we compared the trends of MEA’s (µg/g) to total and fecal coliform concentrations (CFU/g) in sediments from a stream in Northeast Tennessee that had an approved fecal coliform Total Maximum Daily Load (TMDL). The comparisons were based on season and land use through which the stream flowed. Triplicate grab samples of stream sediments were collected monthly for 29 months at 14 sites located in agricultural, urban, and forest regions. Dehydrogenase, acid phosphatase, alkaline phosphatase, galactosidase and glucosidase activities were determined using specific colorimetric analyses. Total coliforms and fecal coliforms were determined using the membrane filtration method. There was significant positive correlation (p<0.05 Pearson) between the total coliform concentrations and all five enzyme activities in the winter (January, February and March). A positive correlation was also seen with alkaline phosphatase in the summer. Fecal coliform concentration was positively correlated with dehydrogenase activity in the winter and spring (April, May and June), and with galactosidase activity in the winter, spring and summer (July, August and September). Fecal coliforms were also positively correlated with acid phosphatase in the summer. Only those sediments located in the urban region showed a positive correlation between total coliforms and dehydrogenase, acid phosphatase, alkaline phosphatase and glucosidase. DHA also showed a positive correlation between total coliforms and the forest region. The only correlation between fecal coliforms and region was with acid phosphatase in the urban region. A strong inverse relationship existed with the ratio of each specific MEA over the fecal coliform concentration versus both the seasons and regions. These correlations show that elevated activities of these five microbial enzymes can serve as another indicator of stream impairment.

Thorough investigation of the glycine conjugation pathway has been neglected over the last 30 years. Environmental factors, nutrition, and the chronic use of medications are increasing the exposure of humans to benzoate and drugs that are metabolized to acyl-CoA intermediates. Glycine conjugation of mitochondrial acyl-CoAs, catalysed by glycine N-acyltransferase (GLYAT, E.C. 2.3.1.13), is an important metabolic pathway responsible for maintaining adequate levels of free coenzyme A (CoASH). However, because of the small number of pharmaceutical drugs that are conjugated to glycine, the pathway has not yet been characterised in detail. Therefore, one of the objectives of this thesis was to develop a better understanding of glycine conjugation and its role in metabolism. In humans and animals a number of endogenous and xenobiotic organic acids are conjugated to glycine. Glycine conjugation has generally been assumed to be a detoxification mechanism, increasing the water solubility of organic acids in order to facilitate urinary excretion. However, recently it was proposed that the role of the amino acid conjugations, including glycine conjugation, is to regulate systemic levels of amino acids that are also utilised as neurotransmitters in the central nervous systems of animals. The glycine deportation hypothesis was based on the observation that, compared to glucuronidation, glycine conjugation does not significantly increase the water solubility of aromatic acids. A thorough review of the literature for this thesis showed that the major role of glycine conjugation, however, is to dispose of the end products of phenylpropionate metabolism. The review also introduced the new perspective that mitochondrial glycine conjugation prevents the accumulation of benzoate in the mitochondrial matrix by forming hippuric acid a less lipophilic conjugate that can be more readily transported out of the mitochondria. Although organic anion transporters can export benzoate from the matrix, this process would likely be futile because benzoic acid can simply diffuse back into the matrix. Hippurate, however, is significantly less lipophilic and therefore less capable of diffusing into the matrix. It is therefore not the transport out of the mitochondrial matrix that is facilitated by glycine conjugation, but rather the ability of the glycine conjugates to re-enter the matrix that is decreased. Lastly, glycine conjugation of benzoate also exacerbates the dietary deficiency of glycine in humans. Because the resulting shortage of glycine can negatively influence brain neurochemistry and the synthesis of collagen, nucleic acids, porphyrins, and other important metabolites, the risks of using benzoate as a preservative should not be underestimated. To date, no defect of the glycine conjugation pathway has been reported and this, together with the fact that GLYAT plays an important role in hepatic metabolism, suggests that this pathway is essential for survival. GLYAT activity affects mitochondrial ATP production, glycine availability, CoASH availability and the toxicity of various organic acids. Therefore, variation in the glycine conjugation pathway could influence liver cancer, musculoskeletal development and mitochondrial energy metabolism. Significant interindividual variation exists in glycine conjugation capacity. The molecular basis for this variability is not known. The main aim of this thesis was to investigate and characterise the genetic variation in the coding region of the GLYAT gene. This was accomplished by firstly, investigating the influence of non-synonymous single nucleotide polymorphisms (SNPs) on the enzyme activity of a recombinant human GLYAT and secondly, by analysing the level of genetic variation in the coding region of the GLYAT gene using existing worldwide population data. To investigate the influence of non-synonymous SNPs in the GLYAT gene on the enzyme activity, a recombinant human GLYAT was prepared, and characterised. Site-directed mutagenesis was used to generate six variants of the enzyme (K16N; S17T; R131H; N156S; F168L; R199C). The variants were expressed, purified, and enzymatically characterised. The enzyme activities of the K16N, S17T and R131H variants were similar to that of the wild-type, whereas the N156S variant was more active, the F168L variant less active, and the R199C variant was inactive. The results showed that SNP variations in the human GLYAT gene can influence the kinetic properties of the enzyme. The genetic variation data of the human GLYAT open reading frame (ORF) available on public databases was investigated by formulating the hypothesis that due to the essential nature of the glycine conjugation pathway, the genetic variation in the ORF of the GLYAT gene should be low and that deleterious alleles will be found at low frequencies. Data from the i) 1000 Genome Project, ii) the HapMap Project, and iii) the Khoi-San/Bantu Sequencing Project was downloaded from available databases. Sequence data of the coding region of a small cohort of South African Afrikaner Caucasian individuals was also generated and included in the analyses. In the GLYAT ORF of the 1537 individuals analysed, only two haplotypes (S156 and T17S156) out of 14 haplotypes were identified in all populations as having the highest haplotype frequencies (70% and 20% respectively). The S156C199 and S156H131 haplotypes, which have a deleterious effect on the enzyme activity of a recombinant human GLYAT, were detected at very low frequencies. The results of this study indicated that the GLYAT ORF is remarkably conserved, which supports the hypothesis that the glycine conjugation pathway is an essential detoxification pathway. The findings presented in this thesis highlight the importance that future investigations should determine the in vivo capacity of the glycine conjugation pathway for the detoxification of benzoate and other xenobiotics. / PhD (Biochemistry), North-West University, Potchefstroom Campus, 2015

Thorough investigation of the glycine conjugation pathway has been neglected over the last 30 years. Environmental factors, nutrition, and the chronic use of medications are increasing the exposure of humans to benzoate and drugs that are metabolized to acyl-CoA intermediates. Glycine conjugation of mitochondrial acyl-CoAs, catalysed by glycine N-acyltransferase (GLYAT, E.C. 2.3.1.13), is an important metabolic pathway responsible for maintaining adequate levels of free coenzyme A (CoASH). However, because of the small number of pharmaceutical drugs that are conjugated to glycine, the pathway has not yet been characterised in detail. Therefore, one of the objectives of this thesis was to develop a better understanding of glycine conjugation and its role in metabolism. In humans and animals a number of endogenous and xenobiotic organic acids are conjugated to glycine. Glycine conjugation has generally been assumed to be a detoxification mechanism, increasing the water solubility of organic acids in order to facilitate urinary excretion. However, recently it was proposed that the role of the amino acid conjugations, including glycine conjugation, is to regulate systemic levels of amino acids that are also utilised as neurotransmitters in the central nervous systems of animals. The glycine deportation hypothesis was based on the observation that, compared to glucuronidation, glycine conjugation does not significantly increase the water solubility of aromatic acids. A thorough review of the literature for this thesis showed that the major role of glycine conjugation, however, is to dispose of the end products of phenylpropionate metabolism. The review also introduced the new perspective that mitochondrial glycine conjugation prevents the accumulation of benzoate in the mitochondrial matrix by forming hippuric acid a less lipophilic conjugate that can be more readily transported out of the mitochondria. Although organic anion transporters can export benzoate from the matrix, this process would likely be futile because benzoic acid can simply diffuse back into the matrix. Hippurate, however, is significantly less lipophilic and therefore less capable of diffusing into the matrix. It is therefore not the transport out of the mitochondrial matrix that is facilitated by glycine conjugation, but rather the ability of the glycine conjugates to re-enter the matrix that is decreased. Lastly, glycine conjugation of benzoate also exacerbates the dietary deficiency of glycine in humans. Because the resulting shortage of glycine can negatively influence brain neurochemistry and the synthesis of collagen, nucleic acids, porphyrins, and other important metabolites, the risks of using benzoate as a preservative should not be underestimated. To date, no defect of the glycine conjugation pathway has been reported and this, together with the fact that GLYAT plays an important role in hepatic metabolism, suggests that this pathway is essential for survival. GLYAT activity affects mitochondrial ATP production, glycine availability, CoASH availability and the toxicity of various organic acids. Therefore, variation in the glycine conjugation pathway could influence liver cancer, musculoskeletal development and mitochondrial energy metabolism. Significant interindividual variation exists in glycine conjugation capacity. The molecular basis for this variability is not known. The main aim of this thesis was to investigate and characterise the genetic variation in the coding region of the GLYAT gene. This was accomplished by firstly, investigating the influence of non-synonymous single nucleotide polymorphisms (SNPs) on the enzyme activity of a recombinant human GLYAT and secondly, by analysing the level of genetic variation in the coding region of the GLYAT gene using existing worldwide population data. To investigate the influence of non-synonymous SNPs in the GLYAT gene on the enzyme activity, a recombinant human GLYAT was prepared, and characterised. Site-directed mutagenesis was used to generate six variants of the enzyme (K16N; S17T; R131H; N156S; F168L; R199C). The variants were expressed, purified, and enzymatically characterised. The enzyme activities of the K16N, S17T and R131H variants were similar to that of the wild-type, whereas the N156S variant was more active, the F168L variant less active, and the R199C variant was inactive. The results showed that SNP variations in the human GLYAT gene can influence the kinetic properties of the enzyme. The genetic variation data of the human GLYAT open reading frame (ORF) available on public databases was investigated by formulating the hypothesis that due to the essential nature of the glycine conjugation pathway, the genetic variation in the ORF of the GLYAT gene should be low and that deleterious alleles will be found at low frequencies. Data from the i) 1000 Genome Project, ii) the HapMap Project, and iii) the Khoi-San/Bantu Sequencing Project was downloaded from available databases. Sequence data of the coding region of a small cohort of South African Afrikaner Caucasian individuals was also generated and included in the analyses. In the GLYAT ORF of the 1537 individuals analysed, only two haplotypes (S156 and T17S156) out of 14 haplotypes were identified in all populations as having the highest haplotype frequencies (70% and 20% respectively). The S156C199 and S156H131 haplotypes, which have a deleterious effect on the enzyme activity of a recombinant human GLYAT, were detected at very low frequencies. The results of this study indicated that the GLYAT ORF is remarkably conserved, which supports the hypothesis that the glycine conjugation pathway is an essential detoxification pathway. The findings presented in this thesis highlight the importance that future investigations should determine the in vivo capacity of the glycine conjugation pathway for the detoxification of benzoate and other xenobiotics. / PhD (Biochemistry), North-West University, Potchefstroom Campus, 2015