Objetivou-se avaliar a influência da monensina sódica sobre o acúmulo hepático de cobre em ovinos. Haja vista, que ionóforos podem alterar a absorção, disponibilidade e distribuição tecidual de minerais em muitos tecidos do organismo. Foram utilizados 24 ovinos mestiços das raças Santa Inês x Dorper com média de três meses de idade e peso medio de 30 kg ao início do experimento, que receberam dieta basal calculada em 2,75% do peso corpóreo, sendo 50% de concentrado comercial (7,13 ppm de Cu) e 50% de feno de capim coast-cross (3,72 ppm de Cu) e 10 gramas de sal mineral (5,9 ppm de Cu). Os cordeiros foram distribuídos em quatro grupos distintos, sendo: Controle apenas dieta basal; Monensina (Mon) - dieta basal e 30 ppm de monensina sódica; Cobre (Cu) - dieta basal acrescida de 10 mg/kg P.V./dia de cobre, na forma de sulfato de cobre pentahidratado; e grupo Monensina+Cobre (MonCu) - dieta basal acrescida de 10 mg/kg P.V./dia de cobre e 30 ppm de monensina sódica. O período experimental teve duração de 14 semanas. Foram coletadas amostras de figado e bile no início por biópsia, e ao final do experimento por necropsia, para determinação de minerais, assim como amostras semanais de sangue para avaliação bioquímica, hematológica e mineral. Foi realizada análise estatística por meio de fatorial 2x2 considerando como fatores a inclusão ou não de cobre e monensina na dieta. Somente um animal apresentou quadro clínico de intoxicação cúprica acumulativa. As concentrações de cobre no fígado no início do experimento variaram entre 243,8 e 345,4 ppm não havendo diferença entre os grupos experimentais. As concentrações médias e desvios-padrão em ppm do cobre hepático ao final do experimento foram 3.363 ± 576 para o grupo MonCu; 2560 ± 524 para o grupo Cu; 562 ± 168 para o grupo Mon e 253 ± 131 para o grupo Controle. Ao final do estudo a concentração de cobre hepático foi influenciada pela suplementação com cobre (P = 0,0001) e monensina (P = 0,0003). Os grupos suplementados com cobre tiveram redução dos teores de ferro hepático (P = 0,0287) e aumento das concentrações de cobre na bile. A avaliação bioquimica demonstrou elevação da atividade sérica da GGT e AST (P < 0,05) nos grupos Cu e MonCu a partir da décima primeira semana do experimento em relação aos grupos Controle e Mon. O aumento da atividade destas enzimas foram influenciadas pela suplementação de cobre (P = 0,0340), enquanto os grupos suplementados com monensina apresentaram menores valores de creatinina quinase. Os resultados obtidos permitem concluir que a monensina interfere positivamente com o acúmulo hepático de cobre sendo que a sumplentação deste aditivo pode predispor a quadros de intoxicações cúprica em ovinos. / The aim of this study was to verify if monensin can change the accumulation of cooper in the liver of sheep, in view of ionophores can alter the absorption, availability, tiissue distribution of many minerals in the body. Twenty four crossbred Dorper X Santa Inês lambs wiht mean age of 3 months and wheitgh 30 kg at the begining of trial recived a basal diete calculated by 2,75% of body wheigth of 50% concentrade (7,13 ppm of Cu) and 50% cost-cross hay (3,72 ppm of Cu) and 10 g of mineral salt (5,9 ppm of Cu). Lambs were randomly distributed in four groups: Control: basal diet, Mon Group reciving basal diet plus 30 mg of monensin; Cu group: basal diet plus 10 mg Cu B.W of CuSO4.5H2O solution; Group CuMon: basal diet plus 30 mg of monensin and 10 mg of Cu B.W. The exeperimental period lasted for fourteen weeks. Liver samples were obtined by liver biopsy initially and at the end by necropsy when lambs were slaughterd. Blood samples were obtained weekly for determination of biochemical, hematological and mineral. Statistical analysis using a 2x2 factorial was conducted considering the factors copper and monensin in the diet and the interaction between them to evaluate the hepatic copper at the beginning and at the end of the study. Only one of animal of group MonCu exhibit clinical sings of copper toxicosis. Copper concentrations in the liver at the beginning of the experiment ranged between 243,8 and 345,4 ppm with no difference between experimental groups. Mean concentrations and standard deviations in ppm of hepatic copper at the end of the experiment were 3,363 ± 576 for MonCu group; 2560 ± 524 for Cu group; 562 ± 168 for the Mon group and 2538 ± 131 for the control group. At the end of the study liver concentrations and total hepatic copper accumulation were influenced both by the amount of dietary copper (P = 0.0001) and of monensin (P = 0.0003). The groups supplemented with copper had reduced levels of hepatic iron (P = 0.0287) and increased concentrations of copper in the bile. The biochemical evaluation demonstrated elevated serum AST and GGT activity (P <0.05) with Cu and MonCu from the eleventh week of the experiment compared to the control groups and Mon. The increased activity of these enzymes were influenced by copper supplementation (P = 0.0340), while group monensin had lower values of creatinine kinase. The results indicate that monensin interferes positively with hepatic copper accumulation and supplementation of this additive can predispose cupric poisoning in sheep.

O objetivo do experimento I foi determinar o efeito da inclusão de narasina na mistura mineral para novilhas alimentadas com forragem. Foram utilizadas 30 novilhas Nelore, distribuídas em 10 baias (3 animais/baia) com peso médio inicial de 222 &plusmn; 3,0 kg. As novilhas foram alimentadas diariamente com pré-secado de cynodon spp. Os tratamentos experimentais foram 0, 650 e 1300 mg de narasina/kg de mistura mineral (0N, 6,5N e 13N, respectivamente). As variáveis analisadas foram consumo de matéria seca (CMS), consumo de mistura mineral (CMM) diário, ganho médio diário (GMD), conversão alimentar (CA) e variação na ingestão da IMM. O delineamento experimental utilizado foi change-over (todas as baias passaram por todos os tratamentos), com um período experimental de 28 dias, e 7 dias destinado ao período tampão (wash-out). A adição de narasina não afetou o CMM (P &#61; 0,75) e nem o CMS (P &#61; 0,69). No entanto, o tratamento 13N aumentou o GMD (P &#61; 0,02) e, consequentemente, melhorou a CA (P &#61; 0,05) em comparação com os animais do grupo 0N e 6,5N. Os resultados indicam que houve uma variação da IMM de cada baia e ao longo do período experimental, e essa variação foi semelhante para todos tratamentos. O objetivo do experimento II foi avaliar o efeito da inclusão de narasina no suplemento mineral para o desempenho de novilhas alimentadas com dietas contendo alto teor de concentrado. Foram utilizadas 60 novilhas Nelore, distribuídas em 20 baias (3 animais/baia) com peso médio inicial 245 &plusmn; 4,3 kg. As novilhas foram alimentadas diariamente com uma dieta contendo aproximadamente 16% de bagaço de cana e 84% de concentrado. Os tratamentos experimentais foram 0N e 13N. As variáveis analisadas foram as mesmas do experimento I. O delineamento experimental utilizado foi cross-over (todas as baias passaram por todos os tratamentos), com um período experimental de 28 dias, e 7 dias destinado ao período tampão (wash-out). A inclusão de 1300 mg de narasina/kg de mistura mineral não afetou o GMD (P &#61; 0,06), CMS (P &#61; 0,56) ou CMM (P &#61; 0,33). No entanto, a adição de narasina diminuiu a CA (P &#61; 0,05) em relação ao grupo controle. Semelhante ao experimento I, houve uma grande variação no CMM entre baias e ao longo do período experimental. O objetivo do experimento III foi avaliar se a inclusão de cloreto de sódio (NaCl) como inibidor e o milho moído como estimulador de consumo de mistura mineral, poderia regularizar a frequência e o consumo individual desse suplemento. Foram utilizadas 30 novilhas Nelore (22 meses), distribuídas em 10 baias (3 animais/baia) com peso médio inicial 294 &plusmn; 3,7 kg. As novilhas foram alimentadas diariamente com pré-secado de Cynodon spp. ad libitum. Os tratamentos experimentais foram controle (mistura mineral), 10MM (90% mistura mineral e 10% milho moído), 10M25NaCl (65% mistura mineral, 10% milho moído e 25% NaCl) e 10M50NaCl (40% mistura mineral, 10% milho moído e 50% NaCl). O delineamento experimental utilizado foi igual ao Experimento I. O período experimental teve duração de 15 dias, 7 dias destinados ao período tampão (washout). A análise de variação do CMM utilizado, foi o erro padrão da média (&#42;EPM) de cada dia para cada tratamento (VCMM). O CMS (P &#61; 0,81), GMD (P &#61; 0,27) e CA (P &#61; 0,31) não diferiram entre os tratamentos. A adição de milho moído aumentou e a inclusão de NaCl reduziu o CMM (P &lt; 0,01). O mesmo aconteceu com a VCMM (P &lt; 0,01), onde o EPM aumentou com a inclusão de milho e reduziu quando adicionado de NaCl / The objective of the first trial was to determine the effect of narasin inclusion into the mineral mix for heifers fed high forage diets. Thirty Nellore heifers with initial body weight of 222 &plusmn; 3.0 kg were used and they were distributed in ten pens (three animals per pen) and fed daily with Cynodon spp. haylage. The experimental treatments were 0N, 6.5N and 13N, with the inclusion of 0, 650 and 1300 mg of narasina/kg of MM, respectively. The variables analyzed were dry matter intake (DMI), mineral mix intake (MMI), average daily gain (ADG), feed:gain ratio (F:G) and MMI variation (MMIV). The experimental design used was change over, where all pens go through all treatments, with a 28 days&#39; experimental period and seven days of wash out. The addition of narasin did not affect neither the MMI (P &#61; 0.75) nor the DMI (P &#61; 0.69). However, when compared to 0N and 6.5N, the addition of 1300 mg of narasin increased ADG (P &#61; 0.02), consequently improving the F:G (P &#61; 0.05). The results indicate that there was a MMIV in each pen and over the experimental period, and that variation was similar for all treatments. The objective of the second trial was to evaluate the effects of narasin inclusion into the MM over the performance of heifers fed high concentrate diets. Sixty Nellore heifers with initial BW of 245 &plusmn; 4,3 kg were used. They were distributed in 20 pens (3 animals/pen) and fed daily with a diet containing approximately 16% sugar cane bagasse and 84% concentrate. The experimental treatments were 0N and 13N, with the inclusion of 0 and 1300 mg of narasin/kg of MM, respectively. The experimental design was cross over, in which all pens go through all treatments, with a 28 days experimental period and seven days of wash out. The inclusion of 1300 mg of narasin/kg of MM did not affect the ADG (P &#61; 0.06), the DMI (P &#61; 0.56) and the MMI (P &#61; 0.33). However, it did improve the F:G (P &#61; 0.05) when compared to the control. Similar to the first trial, there was a big variation in MMI between the pens and along the experimental period. The objective of the third trial was to evaluate if the inclusion of Sodium Chloride (NaCl) as an inhibitor and ground corn (Gc) as a MM intake stimulator could regularize the individual frequency and amount of the supplement intake. Thirty Nellore heifers with 22 months old and an initial BW of 294 &plusmn; 3,7 kg were used. They were distributed in ten pens (3 animals/pen) and fed daily, ad libitum, with Cynodon spp. haylage. The experimental treatments were control (100% MM), 10%Gc (90% MM and 10% Gc), 10%Gc&#43;25%NaCl (65% MM, 10% Gc and 25% NaCl) and 10%Gc&#43;50%NaCl (40% MM, 10% Gc and 50% NaCl). The experimental design used was the same as the first trial, with a 15 days&#39; experimental period and 7 days of wash out. The variance analysis used was the mean standard error of each day for each treatment. The DMI (P &#61; 0.92), ADG (P &#61; 0.51) and F:G (P &#61; 0.98) did not differ between treatments. But the addition of Gc increased the MMI and the inclusion of NaCl decreased it (P &lt; 0.01). The same happened with the MMIV (P &lt; 0.01), where the mean standard error increased with the inclusion of Gc and decreased when NaCl was added

Lasalocida é um aditivo nutricional que melhora o desempenho e a eficiência alimentar de bovinos de corte, atua sobre as bactérias ruminais, com maior efetividade sob as bactérias gram-positivas, e com pouca ou quase nenhuma ação sobre as bactérias gram-negativas, resultando em melhor aproveitamento do alimento consumido pelo animal. O objetivo deste estudo foi avaliar o uso do lasalocida no crescimento de bovinos de corte em pastagem através de uma revisão sistemática-metanálise. Foram utilizadas três bases de dados eletrônicas (Scopus, Science Direct e ISI Web of Knowledge). Os critérios para inclusão foram estudos completos, conduzidos em bovinos de corte, com o uso da suplementação com lasalocida e que avaliassem medidas de desempenho animal (ganho médio diário de peso (GMD), escore de condição corporal (ECC) e circunferência escrotal (CE). A extração de dados das publicações foi realizada com o uso de um protocolo pré-definido. Foi conduzida uma metanálise para efeitos aleatórios para cada indicador separadamente com as médias dos grupos controle e tratado. Foram incluídos na análise quatro publicações, que relataram cinco estudos e 16 ensaios conduzidos em 284 bovinos. Não foram obtidos dados suficientes para realização da metanálise (MA) para ECC e CE. Os níveis de heterogeneidade entre estudos foram considerados de baixo a moderado, variando entre 0 e 50,2%. O fornecimento de lasalocida na suplementação energética mostrou tendência em alterar o GMD dos bovinos (DM= -0,288 kg/dia; P= 0,084; IC 95%: -0,615, 0,039; n= 10 ensaios). A comparação entre animais que receberam lasalocida nas concentrações 200 e 300 mg/cabeça/dia, em pastagem natural, mostrou que aqueles que receberam a maior concentração tiveram um menor GMD (DM= -0,474 kg/dia; IC 95%: -0,868, -0,080; P=0,018; n= 2 ensaios). Quando a comparação foi de 0 e 200 mg/cabeça/dia, bovinos com acesso ao ionóforo tiveram um desempenho inferior (DM= -0,599 kg/dia; IC 95%: -1,144, -0,053; p= 0,032; n= 3 ensaios). Por outro lado, quando o controle recebeu 0 mg/cabeça/dia e o tratado 100 mg/cabeça/dia de lasalocida na dieta, não foi encontrada diferença estatística. Assim, a suplementação de bovinos de corte com lasalocida em pastagem não apresentou efeitos sobre o ganho médio diário dos bovinos mantidos em pastagens. / Lasalocid is a nutritional additive that improves the performance and feed efficiency of beef cattle, acts on ruminal bacterium, is more effective under gram-positive bacterium, and with little or no action on gram-negative bacterium, resulting in better use of the food consumed by the animal.The aim of this study was to evaluate the use of lasalocid in the growth of beef cattle on pasture through a systematic review meta-analysis.We searched on three electronic databases (Scopus, Science Direct, and ISI Web of Knowledge), as well as we checked references of relevant review papers.Inclusion criteria were complete studies using beef cattle on pasture receiving lasalocid supplementation that evaluate animal performance (average dalily gain (ADG), body composition score (BCS), and scrotal circumference (SC). Data were extracted using pre-defined protocols. Random effect meta-analyses were conducted for each indicator separately with the mean of control and treated group We included in the analysis four publications, reporting 5 studies, 16 trials in 284 bovines. There are no data available to analyse BCS and SC using MA procedure.The levels of heterogeneity between studies were considered low to moderate, varying between 0 and 50.2%.Thelasalocid additionin energy supplementation showed a tendency to change GMD (DM = -0.288 kg/day; P= 0.084; 95% CI: -0.615, 0.039; n= 10 trials). Comparison between animals receiving lasalocid at 200 and 300 mg/head/day in natural pasture showed that the highest concentration had lower ADG (DM= -0.474 kg/day; 95% CI: -0.868, -0.080; P= 0.018; n = 2 trials). When the comparison was between 0 and 200 mg/head/day, cattle that received the ionophore showed lower performance (DM= -0.599 kg/day; 95% CI: -1.144, -0.053, p = 0.032; n= 3trials). Alternatively, when the control group did not receivedlasalocid and the treatment received 100mg/head/day in the diet, no statistical difference was found.Our study demonstrate that the supplementation with lasalocid to beef cattle in pasture did not change the average daily gain.

O objetivo do experimento I foi determinar o efeito da inclusão de narasina na mistura mineral para novilhas alimentadas com forragem. Foram utilizadas 30 novilhas Nelore, distribuídas em 10 baias (3 animais/baia) com peso médio inicial de 222 &plusmn; 3,0 kg. As novilhas foram alimentadas diariamente com pré-secado de cynodon spp. Os tratamentos experimentais foram 0, 650 e 1300 mg de narasina/kg de mistura mineral (0N, 6,5N e 13N, respectivamente). As variáveis analisadas foram consumo de matéria seca (CMS), consumo de mistura mineral (CMM) diário, ganho médio diário (GMD), conversão alimentar (CA) e variação na ingestão da IMM. O delineamento experimental utilizado foi change-over (todas as baias passaram por todos os tratamentos), com um período experimental de 28 dias, e 7 dias destinado ao período tampão (wash-out). A adição de narasina não afetou o CMM (P &#61; 0,75) e nem o CMS (P &#61; 0,69). No entanto, o tratamento 13N aumentou o GMD (P &#61; 0,02) e, consequentemente, melhorou a CA (P &#61; 0,05) em comparação com os animais do grupo 0N e 6,5N. Os resultados indicam que houve uma variação da IMM de cada baia e ao longo do período experimental, e essa variação foi semelhante para todos tratamentos. O objetivo do experimento II foi avaliar o efeito da inclusão de narasina no suplemento mineral para o desempenho de novilhas alimentadas com dietas contendo alto teor de concentrado. Foram utilizadas 60 novilhas Nelore, distribuídas em 20 baias (3 animais/baia) com peso médio inicial 245 &plusmn; 4,3 kg. As novilhas foram alimentadas diariamente com uma dieta contendo aproximadamente 16% de bagaço de cana e 84% de concentrado. Os tratamentos experimentais foram 0N e 13N. As variáveis analisadas foram as mesmas do experimento I. O delineamento experimental utilizado foi cross-over (todas as baias passaram por todos os tratamentos), com um período experimental de 28 dias, e 7 dias destinado ao período tampão (wash-out). A inclusão de 1300 mg de narasina/kg de mistura mineral não afetou o GMD (P &#61; 0,06), CMS (P &#61; 0,56) ou CMM (P &#61; 0,33). No entanto, a adição de narasina diminuiu a CA (P &#61; 0,05) em relação ao grupo controle. Semelhante ao experimento I, houve uma grande variação no CMM entre baias e ao longo do período experimental. O objetivo do experimento III foi avaliar se a inclusão de cloreto de sódio (NaCl) como inibidor e o milho moído como estimulador de consumo de mistura mineral, poderia regularizar a frequência e o consumo individual desse suplemento. Foram utilizadas 30 novilhas Nelore (22 meses), distribuídas em 10 baias (3 animais/baia) com peso médio inicial 294 &plusmn; 3,7 kg. As novilhas foram alimentadas diariamente com pré-secado de Cynodon spp. ad libitum. Os tratamentos experimentais foram controle (mistura mineral), 10MM (90% mistura mineral e 10% milho moído), 10M25NaCl (65% mistura mineral, 10% milho moído e 25% NaCl) e 10M50NaCl (40% mistura mineral, 10% milho moído e 50% NaCl). O delineamento experimental utilizado foi igual ao Experimento I. O período experimental teve duração de 15 dias, 7 dias destinados ao período tampão (washout). A análise de variação do CMM utilizado, foi o erro padrão da média (&#42;EPM) de cada dia para cada tratamento (VCMM). O CMS (P &#61; 0,81), GMD (P &#61; 0,27) e CA (P &#61; 0,31) não diferiram entre os tratamentos. A adição de milho moído aumentou e a inclusão de NaCl reduziu o CMM (P &lt; 0,01). O mesmo aconteceu com a VCMM (P &lt; 0,01), onde o EPM aumentou com a inclusão de milho e reduziu quando adicionado de NaCl / The objective of the first trial was to determine the effect of narasin inclusion into the mineral mix for heifers fed high forage diets. Thirty Nellore heifers with initial body weight of 222 &plusmn; 3.0 kg were used and they were distributed in ten pens (three animals per pen) and fed daily with Cynodon spp. haylage. The experimental treatments were 0N, 6.5N and 13N, with the inclusion of 0, 650 and 1300 mg of narasina/kg of MM, respectively. The variables analyzed were dry matter intake (DMI), mineral mix intake (MMI), average daily gain (ADG), feed:gain ratio (F:G) and MMI variation (MMIV). The experimental design used was change over, where all pens go through all treatments, with a 28 days&#39; experimental period and seven days of wash out. The addition of narasin did not affect neither the MMI (P &#61; 0.75) nor the DMI (P &#61; 0.69). However, when compared to 0N and 6.5N, the addition of 1300 mg of narasin increased ADG (P &#61; 0.02), consequently improving the F:G (P &#61; 0.05). The results indicate that there was a MMIV in each pen and over the experimental period, and that variation was similar for all treatments. The objective of the second trial was to evaluate the effects of narasin inclusion into the MM over the performance of heifers fed high concentrate diets. Sixty Nellore heifers with initial BW of 245 &plusmn; 4,3 kg were used. They were distributed in 20 pens (3 animals/pen) and fed daily with a diet containing approximately 16% sugar cane bagasse and 84% concentrate. The experimental treatments were 0N and 13N, with the inclusion of 0 and 1300 mg of narasin/kg of MM, respectively. The experimental design was cross over, in which all pens go through all treatments, with a 28 days experimental period and seven days of wash out. The inclusion of 1300 mg of narasin/kg of MM did not affect the ADG (P &#61; 0.06), the DMI (P &#61; 0.56) and the MMI (P &#61; 0.33). However, it did improve the F:G (P &#61; 0.05) when compared to the control. Similar to the first trial, there was a big variation in MMI between the pens and along the experimental period. The objective of the third trial was to evaluate if the inclusion of Sodium Chloride (NaCl) as an inhibitor and ground corn (Gc) as a MM intake stimulator could regularize the individual frequency and amount of the supplement intake. Thirty Nellore heifers with 22 months old and an initial BW of 294 &plusmn; 3,7 kg were used. They were distributed in ten pens (3 animals/pen) and fed daily, ad libitum, with Cynodon spp. haylage. The experimental treatments were control (100% MM), 10%Gc (90% MM and 10% Gc), 10%Gc&#43;25%NaCl (65% MM, 10% Gc and 25% NaCl) and 10%Gc&#43;50%NaCl (40% MM, 10% Gc and 50% NaCl). The experimental design used was the same as the first trial, with a 15 days&#39; experimental period and 7 days of wash out. The variance analysis used was the mean standard error of each day for each treatment. The DMI (P &#61; 0.92), ADG (P &#61; 0.51) and F:G (P &#61; 0.98) did not differ between treatments. But the addition of Gc increased the MMI and the inclusion of NaCl decreased it (P &lt; 0.01). The same happened with the MMIV (P &lt; 0.01), where the mean standard error increased with the inclusion of Gc and decreased when NaCl was added

Most (99%) mitochondrial proteins are nuclear-encoded and must be imported into mitochondria. Deficits in mitochondrial protein import (MPI) affect mitochondrial function and can cause neurodegenerative diseases. I hypothesized that MPI was regulated by iCa2+. In differentiated PC12 cells, treatment with the Ca2+ ionophore (A23187; 24h, 0.15uM) increased iCa2+, ROS generation and promoted neurite outgrowth. Western blot and flow cytometry in live cells showed that A23187 increased levels of mitochondrial proteins; mtHSP70 and mtGFP in mitochondria and autoradiography confirmed that A23187 increased the import of mtGFP. A23187 also slowed intramitochondrial mtGFP degradation. Increased MPI was not associated with mitochondrial biogenesis, but appeared partially dependent on cAMP. In rat cortical neurons, mtHSP70 also increased after A23187 treatment. These results show that, in neurons, increased iCa2+ can regulate MPI. Further, increased iCa2+ can slow intramitochondrial protein degradation. These results indicate that MPI is labile and may be altered in response to neuronal activity.

Most (99%) mitochondrial proteins are nuclear-encoded and must be imported into mitochondria. Deficits in mitochondrial protein import (MPI) affect mitochondrial function and can cause neurodegenerative diseases. I hypothesized that MPI was regulated by iCa2+. In differentiated PC12 cells, treatment with the Ca2+ ionophore (A23187; 24h, 0.15uM) increased iCa2+, ROS generation and promoted neurite outgrowth. Western blot and flow cytometry in live cells showed that A23187 increased levels of mitochondrial proteins; mtHSP70 and mtGFP in mitochondria and autoradiography confirmed that A23187 increased the import of mtGFP. A23187 also slowed intramitochondrial mtGFP degradation. Increased MPI was not associated with mitochondrial biogenesis, but appeared partially dependent on cAMP. In rat cortical neurons, mtHSP70 also increased after A23187 treatment. These results show that, in neurons, increased iCa2+ can regulate MPI. Further, increased iCa2+ can slow intramitochondrial protein degradation. These results indicate that MPI is labile and may be altered in response to neuronal activity.

<p>This work examines the characterization of supramolecular assemblies and, more specifically, host-guest complexes involved in molecular recognition events. The supramolecular assemblies studied take root from metal ion delivery in biological uptake pathways, specifically the delivery of iron to microbial cells. These assemblies are studied in an effort to further understand the nature of molecular recognition events, specifically the nature and strength of interactions between a host and a guest, and possible applications of these systems. </p> <p>The development of a mass spectral method by which to characterize supramolecular assemblies involving the cation binding hosts 18-crown-6, benzo-18-crown-6, dicyclohexano-18-crown-6, and dibenzo-18-crown-6 macrocycles, and the linear ionophore lasalocid with cationic guests, including substituted protonated amines and the iron siderophore ferrioxamine B is presented. Methodology was developed using ESI-MS to successfully quantitate host-guest interactions in binary and complex mixtures. Binding constants were obtained in the range of log Ka = 3 - 5 and correspond to similar systems previously studied in the literature. The studies presented here further our understanding of the molecular recognition events that must occur between a siderophore and a receptor and provide an improved method by which to measure the strength of their interaction. </p> <p>The effects of redox hosts on host-guest complex formation with ferrioxamine B and the characterization of the host-guest complexes formed and the strength of the interactions between them were studied using cyclic voltammetry, ESI-MS, FAB-MS and ITC. A shift in redox potential towards more positive values is observed upon addition of a cationic siderophore guest to a solution of a redox-active para-Wurster's aza crown or mono-substituted Wurster's aza crown macrocycle. Mass spectral evidence indicates the formation of a host-guest complex between the cationic siderophore and the redox host. A redox switch mechanism is proposed, whereby the redox state of the host influences the binding affinity between the host and guest and, consequently, host-guest complex formation. These systems offer a unique means by which to modulate the uptake or release of ionic guests from a cavity by using externally controlled methods and can be applied to selective metal ion compartmentalization. </p> <p>Finally, the application of supramolecular assemblies as a tool in the field of drug delivery is presented. The covalent attachment of an antimalarial drug, artemisinin, by our collaborators to a siderophore produced by M. Tuberculosis, mycobactin, facilitates the subsequent delivery of the drug into the microbial cell by taking advantage of the natural biological iron uptake pathway. Here, the molecular recognition event and supramolecular assembly of interest is that occurring between the siderophore-drug assembly and the microbial receptor. Characterization of the siderophore-drug assembly using cyclic voltammetry shows that there is an interaction between the Fe-mycobactin and artemisinin when these are covalently attached in the form of a conjugate. Increased current output is observed due to an intramolecular electron transfer between the two components. Based on these in vitro data, we propose a redox mechanism by which the drug-siderophore conjugate exhibits a therapeutic effect in vivo.</p> / Dissertation

Over the past several decades, our understanding of the immune system has advanced considerably. With it, an appreciation for its role in a number of diseases, such as cancer and infection has significantly grown. While our increased understanding of the immunological mechanisms underlying these diseases has improved treatment, considerable morbidity and mortality from these illnesses still exists signifying the need for more effective and innovative therapies. Dendritic cell (DC) therapy has been shown to be a promising approach to induce strong immune responses for immunotherapy, and biomaterial-based strategies have been developed to target DCs in vivo to facilitate this purpose. Given the importance of calcium in DC function and activation, we hypothesized that we could develop a biomaterial-based approach to locally and specifically control calcium signaling in DCs in vivo as a novel strategy for immunotherapy. Our first sub-hypothesis was that the calcium used to crosslink alginate gels, a commonly used biomaterial, could activate DCs in vitro; our second sub-hypothesis was that calcium ionophore A23187 could be delivered from biomaterials to activate DCs in vitro; and our third sub-hypothesis was that calcium used to crosslink alginate gels and/or controlled delivery of A23187 could increase local inflammation in vivo. We found that both the calcium released from calcium alginate gels and A23187 matured DCs and enhanced TLR-induced inflammatory cytokine secretion in vitro. Although we were unable to effectively deliver A23187 in vivo, calcium alginate gels injected subcutaneously were able to upregulate a number of inflammatory cytokines and chemokines relative to barium alginate gels. Likewise, when LPS was delivered from calcium alginate gels, the inflammatory effects of LPS on surrounding tissue were enhanced compared to when it was delivered from barium alginate gels. Thus, we confirmed that the calcium crosslinker in alginate gels could activate DCs, and provided a proof-of-principle that calcium signaling could be harnessed in vivo to enhance the immune response. Not only does this work impact the future of biomaterial design, but it may also enhance our understanding of DC biology. This thesis lays the groundwork for a novel and potentially effective strategy for enhancing DC activation in vivo, and suggests that ion signaling pathways in other cell types (both immune and non-immune) could also be targeted using biomaterials. / Engineering and Applied Sciences

Techn. Universiẗat, Diss., 2004--Dresden.

Lasalocida é um aditivo nutricional que melhora o desempenho e a eficiência alimentar de bovinos de corte, atua sobre as bactérias ruminais, com maior efetividade sob as bactérias gram-positivas, e com pouca ou quase nenhuma ação sobre as bactérias gram-negativas, resultando em melhor aproveitamento do alimento consumido pelo animal. O objetivo deste estudo foi avaliar o uso do lasalocida no crescimento de bovinos de corte em pastagem através de uma revisão sistemática-metanálise. Foram utilizadas três bases de dados eletrônicas (Scopus, Science Direct e ISI Web of Knowledge). Os critérios para inclusão foram estudos completos, conduzidos em bovinos de corte, com o uso da suplementação com lasalocida e que avaliassem medidas de desempenho animal (ganho médio diário de peso (GMD), escore de condição corporal (ECC) e circunferência escrotal (CE). A extração de dados das publicações foi realizada com o uso de um protocolo pré-definido. Foi conduzida uma metanálise para efeitos aleatórios para cada indicador separadamente com as médias dos grupos controle e tratado. Foram incluídos na análise quatro publicações, que relataram cinco estudos e 16 ensaios conduzidos em 284 bovinos. Não foram obtidos dados suficientes para realização da metanálise (MA) para ECC e CE. Os níveis de heterogeneidade entre estudos foram considerados de baixo a moderado, variando entre 0 e 50,2%. O fornecimento de lasalocida na suplementação energética mostrou tendência em alterar o GMD dos bovinos (DM= -0,288 kg/dia; P= 0,084; IC 95%: -0,615, 0,039; n= 10 ensaios). A comparação entre animais que receberam lasalocida nas concentrações 200 e 300 mg/cabeça/dia, em pastagem natural, mostrou que aqueles que receberam a maior concentração tiveram um menor GMD (DM= -0,474 kg/dia; IC 95%: -0,868, -0,080; P=0,018; n= 2 ensaios). Quando a comparação foi de 0 e 200 mg/cabeça/dia, bovinos com acesso ao ionóforo tiveram um desempenho inferior (DM= -0,599 kg/dia; IC 95%: -1,144, -0,053; p= 0,032; n= 3 ensaios). Por outro lado, quando o controle recebeu 0 mg/cabeça/dia e o tratado 100 mg/cabeça/dia de lasalocida na dieta, não foi encontrada diferença estatística. Assim, a suplementação de bovinos de corte com lasalocida em pastagem não apresentou efeitos sobre o ganho médio diário dos bovinos mantidos em pastagens. / Lasalocid is a nutritional additive that improves the performance and feed efficiency of beef cattle, acts on ruminal bacterium, is more effective under gram-positive bacterium, and with little or no action on gram-negative bacterium, resulting in better use of the food consumed by the animal.The aim of this study was to evaluate the use of lasalocid in the growth of beef cattle on pasture through a systematic review meta-analysis.We searched on three electronic databases (Scopus, Science Direct, and ISI Web of Knowledge), as well as we checked references of relevant review papers.Inclusion criteria were complete studies using beef cattle on pasture receiving lasalocid supplementation that evaluate animal performance (average dalily gain (ADG), body composition score (BCS), and scrotal circumference (SC). Data were extracted using pre-defined protocols. Random effect meta-analyses were conducted for each indicator separately with the mean of control and treated group We included in the analysis four publications, reporting 5 studies, 16 trials in 284 bovines. There are no data available to analyse BCS and SC using MA procedure.The levels of heterogeneity between studies were considered low to moderate, varying between 0 and 50.2%.Thelasalocid additionin energy supplementation showed a tendency to change GMD (DM = -0.288 kg/day; P= 0.084; 95% CI: -0.615, 0.039; n= 10 trials). Comparison between animals receiving lasalocid at 200 and 300 mg/head/day in natural pasture showed that the highest concentration had lower ADG (DM= -0.474 kg/day; 95% CI: -0.868, -0.080; P= 0.018; n = 2 trials). When the comparison was between 0 and 200 mg/head/day, cattle that received the ionophore showed lower performance (DM= -0.599 kg/day; 95% CI: -1.144, -0.053, p = 0.032; n= 3trials). Alternatively, when the control group did not receivedlasalocid and the treatment received 100mg/head/day in the diet, no statistical difference was found.Our study demonstrate that the supplementation with lasalocid to beef cattle in pasture did not change the average daily gain.