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1.
Biol Pharm Bull ; 43(9): 1407-1412, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32879215

RESUMO

The role of ß-estradiol (E2) in lipoprotein metabolism in mammary tumors is unclear, therefore, we investigated the effect of E2 on the secretion of lipoprotein lipase (LPL) from mouse mammary tumor FM3A cells. E2-treated cells increased the secretion of active LPL from FM3A cells in a time- and dose-dependent manner. Activity of mitogen-activated protein kinase (MAPK) was increased in the tumor cells treated with E2, and enhanced secretion of LPL was suppressed by MAPK kinase 1/2 inhibitor, PD98059, extracellular signal-regulated kinase (ERK) 1/2 inhibitor, FR180204, p38 MAPK inhibitor, SB202190, and phosphatidyl inositol 3-kinase (PI3K) inhibitor, LY294002. In addition, the effect of E2 on LPL secretion was markedly suppressed by an inhibitor of mammalian target of rapamycin complex (mTORC) 1 and 2, KU0063794, but were not by a mTORC1 inhibitor, rapamycin. Furthermore, a small interfering RNA (siRNA)-mediated decrease in the expression of rapamycin-insensitive companion of mTOR (Rictor), a pivotal component of mTORC2, suppressed secretion of LPL by E2. These results suggest that the stimulatory secretion of LPL by E2 from the tumor cells is closely associated with an activation of mTORC2 rather than mTORC1 possibly via the MAPK cascade.


Assuntos
Estradiol/metabolismo , Lipase Lipoproteica/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Neoplasias Mamárias Animais/patologia , Proteína Companheira de mTOR Insensível à Rapamicina/metabolismo , Animais , Linhagem Celular Tumoral , Meios de Cultura/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/fisiologia , Lipoproteínas/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Morfolinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Proteína Companheira de mTOR Insensível à Rapamicina/antagonistas & inibidores , Proteína Companheira de mTOR Insensível à Rapamicina/genética
2.
J Comp Physiol B ; 188(6): 1005-1014, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30194463

RESUMO

Daily torpor is a strategy used by some overwintering small endotherms to aid in energy conservation. However, the pattern of torpor varies among individuals within species and populations, even under the same environmental conditions, with significant implications for survival rate and reproductive success. Body mass is one factor that may influence this variation, especially in some small mammals that accumulate fat stores prior to overwintering. However, to our knowledge there has been no previous study examining the detailed relationships between torpor expression and body mass change in small mammals that hoard food as an energy resource during winter. The large Japanese field mouse, Apodemus speciosus, whose winter survival strategy depends on food caches instead of fat stores, displays daily torpor under artificial winter conditions (short-day photoperiod and cold). The present study clarifies the characteristics and patterns of daily torpor and body mass change in this species in the laboratory. Although expression of daily torpor was facilitated progressively as in other species, the observed patterns of torpor expression and body mass change showed considerable individual variation. Moreover, there was no obvious correlation between body mass and daily torpor expression. Therefore, it is suggested that in A. speciosus body mass may not contribute to individual variation of daily torpor during winter. Daily torpor during winter may be adjusted by not only mechanisms common to other small mammals, but also species-specific factors relating to the external or internal reserves of energy in small mammals.


Assuntos
Murinae/fisiologia , Torpor/fisiologia , Animais , Peso Corporal , Feminino , Masculino , Estações do Ano
3.
J Exp Biol ; 221(Pt 12)2018 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-29678821

RESUMO

Daily torpor is a physiological adaptation in small mammals and birds, characterised by drastic reductions in metabolism and body temperature. Energy-constraining conditions, such as cold and starvation, are known to cause the expression of daily torpor. However, the reason for high degrees of inter- and intra-individual variation in torpor expression (TE) in similar situations is not clear. As littermates of altricial animals are exposed to an uneven allocation of maternal resources from conception to weaning, we tested whether early nutritional experiences have long-term effects on TE in adults. We used full-sibling littermates of laboratory mice that as adults were starved overnight to induce torpor. We measured body mass from birth until adulthood as an indicator of nutritional status, and calculated the relative body mass (RBM) as an indicator of the difference in nutritional status within a litter. After maturation, we subjected mice to five repeated torpor induction trials involving 24 h of fasting and 5 days of recovery. Half of the female mice displayed great individual variation in TE whereas male mice rarely exhibited daily torpor. In females, RBM at birth influenced TE, irrespective of body mass in adulthood; thus, female mice born with low RBMs displayed high TE in adulthood. In conclusion, we provide evidence that TE in mice differs among littermates, and that this variation is linked closely to heterogeneous nutritional experiences during the fetal period.


Assuntos
Peso ao Nascer , Camundongos/fisiologia , Torpor/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Feminino , Individualidade , Masculino , Camundongos Endogâmicos ICR , Fatores Sexuais
4.
Exp Anim ; 66(4): 321-327, 2017 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-28626157

RESUMO

Daily torpor is a physiological adaptation in mammals and birds characterized by a controlled reduction of metabolic rate and body temperature during the resting phase of circadian rhythms. In laboratory mice, daily torpor is induced by dietary caloric restriction. However, it is not known which nutrients are related to daily torpor expression. To determine whether dietary protein is a key factor in inducing daily torpor in mice, we fed mice a protein-restricted (PR) diet that included only one-quarter of the amount of protein but the same caloric level as a control (C) diet. We assigned six non-pregnant female ICR mice to each group and recorded their body weights and core body temperatures for 4 weeks. Body weights in the C group increased, but those in the PR group remained steady or decreased. Mice in both groups did not show daily torpor, but most mice in a food-restricted group (n=6) supplied with 80% of the calories given to the C group exhibited decreased body weights and frequently displayed daily torpor. This suggests that protein restriction is not a trigger of daily torpor; torpid animals can conserve their internal energy, but torpor may not play a significant role in conserving internal protein. Thus, opportunistic daily torpor in mice may function in energy conservation rather than protein saving.


Assuntos
Animais de Laboratório/fisiologia , Regulação da Temperatura Corporal/fisiologia , Dieta com Restrição de Proteínas , Proteínas na Dieta/administração & dosagem , Camundongos Endogâmicos ICR/metabolismo , Camundongos Endogâmicos ICR/fisiologia , Torpor/fisiologia , Animais , Peso Corporal , Metabolismo Energético/fisiologia , Feminino
5.
Biochem Biophys Res Commun ; 486(2): 476-480, 2017 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-28315682

RESUMO

Both cholesterol and α-tocopherol are essential lipophilic nutrients for humans and animals. Although cholesterol in excess causes severe problems such as coronary heart disease, it is a necessary component of cell membranes and is the precursor for the biosynthesis of steroid hormones and bile acids. Niemann-Pick C1-like 1 (NPC1L1) is a cholesterol transporter that is highly expressed in the small intestine and liver in humans and plays an important role in cholesterol homeostasis. Cholesterol promotes NPC1L1 endocytosis, which is an early step in cholesterol uptake. Furthermore, α-tocopherol is the most active form of vitamin E, and sufficient amounts of vitamin E are critical for health. It has been reported that NPC1L1 mediates α-tocopherol absorption; however, the mechanisms underlying this process are unknown. In this study, we found that treatment of cells that stably express NPC1L1-GFP with α-tocopherol promotes NPC1L1 endocytosis, and the NPC1L1 inhibitor, ezetimibe, efficiently prevents the α-tocopherol-induced endocytosis of NPC1L1. Cholesterol binding to the N-terminal domain (NTD) of NPC1L1 (NPC1L1-NTD) is essential for NPC1L1-mediated cholesterol absorption. We found that α-tocopherol competitively binds NPC1L1-NTD with cholesterol. Furthermore, when cells stably expressed NPC1L1ΔNTD-GFP, α-tocopherol could not induce the endocytosis of NPC1L1ΔNTD. Taken together, these results demonstrate that NPC1L1 recognizes α-tocopherol via its NTD and mediates α-tocopherol uptake through the same mechanism as cholesterol absorption.


Assuntos
Colesterol/metabolismo , Hepatócitos/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , alfa-Tocoferol/metabolismo , Animais , Anticolesterolemiantes/farmacologia , Ligação Competitiva , Transporte Biológico , Células CACO-2 , Linhagem Celular Tumoral , Colesterol/farmacologia , Endocitose/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Ezetimiba/farmacologia , Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Humanos , Proteínas de Membrana/química , Proteínas de Membrana/genética , Proteínas de Membrana Transportadoras , Plasmídeos/química , Plasmídeos/metabolismo , Ligação Proteica , Domínios Proteicos , Ratos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética
6.
Anim Sci J ; 88(3): 413-420, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27417411

RESUMO

Polymorphisms in genes involved in lipid metabolism have been reported to be associated with fatty acid composition of adipose tissue. However, the relationship of these polymorphisms with premortem ultrasonic traits is unknown. The objective of this study, therefore, was to assess the association between polymorphisms in fatty acid synthase, stearoyl-coenzyme A desaturase (SCD), sterol regulatory element-binding protein 1 (SREBP1), diacylglycerol acyltransferase 1, and nuclear receptor subfamily 1, group H, number 3 genes with ultrasonic and carcass traits in Japanese Black steers (n = 300) under progeny testing at the Livestock Improvement Association of Miyazaki. To have a comprehensive analysis of the association between the aforementioned genetic polymorphisms and ultrasonic traits, longitudinal measurements of ultrasonic traits were taken. Furthermore, the association of these genetic polymorphisms and carcass traits was evaluated. The polymorphisms in the SCD gene and SREBP1 were associated (P < 0.05) with some ultrasonic traits at multiple stages. To add to that, the polymorphisms were associated (P < 0.05) with some carcass traits. These findings suggest that the polymorphisms in SCD and SREBP1 are functional mutations or could be related to mutations that can aid in selection to improve some ultrasonic and carcass traits.


Assuntos
Bovinos/genética , Bovinos/metabolismo , Ácido Graxo Sintase Tipo I/genética , Estudos de Associação Genética , Metabolismo dos Lipídeos/genética , Músculo Esquelético/diagnóstico por imagem , Polimorfismo Genético , Característica Quantitativa Herdável , Tecido Adiposo/metabolismo , Animais , Masculino , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/metabolismo , Mutação , Estearoil-CoA Dessaturase/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Ultrassonografia
7.
Pharmacol Rep ; 68(3): 649-53, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27031052

RESUMO

BACKGROUND: Prazosin is an α1 adrenoceptor antagonist used in pharmacotherapy for the treatment of hypertension. Prazosin alters lipid metabolism in vivo, but the involved mechanism is not fully understood. In this study, we investigated the mechanism underlying the alteration of lipid metabolism. We show that the prazosin-stimulated release of hepatic triacylglyceride lipase (HTGL) from primary cultured rat hepatocytes involved Ca(2+)/calmodulin-dependent protein kinase II (CaMK-II) activation. METHODS: Primary cultured rat hepatocytes were incubated with prazosin and other agents. The hepatocytes were used in the CaMK-II and protein kinase A (PKA) activity assay. The supernatant was used in the HTGL activity assay and western blotting. RESULTS: Prazosin-stimulated HTGL release was suppressed by the inositol triphosphate receptor inhibitor xestospongin C and by the calmodulin inhibitor trifluoperazine but not by the protein kinase C inhibitor chelerythrine chloride or a diacylglycerol kinase inhibitor (R59949). Furthermore, the calmodulin-dependent protein kinase II (CaMK-II) activity in prazosin-treated hepatocytes increased in a time- and dose-dependent manner. The cAMP-dependent PKA activity of prazosin-stimulated hepatocytes was suppressed by a phospholipase C (PLC) inhibitor (U-73122), trifluoperazine, and a CaMK-II inhibitor (KN-93). CONCLUSIONS: These results suggested that prazosin-stimulated HTGL release from hepatocytes was caused by activation of PKA associated with stimulation of CaMK-II activity through a signal cascade from PLC.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Hepatócitos/metabolismo , Lipase Lipoproteica/metabolismo , Prazosina/farmacologia , Animais , Benzofenantridinas/farmacologia , Benzilaminas/farmacologia , Relação Dose-Resposta a Droga , Estrenos/farmacologia , Compostos Macrocíclicos/farmacologia , Masculino , Oxazóis/farmacologia , Piperidinas/farmacologia , Prazosina/antagonistas & inibidores , Cultura Primária de Células , Pirrolidinonas/farmacologia , Quinazolinonas/farmacologia , Ratos , Sulfonamidas/farmacologia , Fatores de Tempo , Trifluoperazina/farmacologia
8.
Physiol Behav ; 139: 519-23, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25483213

RESUMO

Many small mammal species use torpor as a strategy for reducing energy expenditure in winter. Some rodent hibernators also hoard food to provide reserves of energy, and individuals with large hoards express less torpor than those with smaller reserves. These facts imply that animals can recognize levels of food availability, but where food is very plentiful, it is unclear whether torpor expression is affected by temporal changes in the extent of food overabundance. Moreover, the relationship between daily torpor and excess food availability has not been clearly established. The large Japanese field mouse Apodemus speciosus caches food for use as a winter energy resource and exhibits daily torpor under artificial winter conditions. The present study examined whether individuals exposed to different magnitudes of overabundant food exhibited differences in expression of daily torpor, and secondly whether torpor expression varied in response to changes in the overall quantity of overabundant food. It was observed that while absolute quantities of overabundant food did not appear to affect daily torpor expression, the mice did respond to changes in food availability, even when food remained overabundant. This suggests that the mice respond to fluctuations in food availability, even where these changes do not place any constraint on energy budgets. Thus recognition of changing food availability cannot be a purely physiological response to shortage or plenty, and may contribute to predictions of future energy availability. The expression of torpor was inhibited in response to increasing food availability, and the mice used shallower torpor when food availability increased to superabundance. These findings suggest that daily torpor may be regulated not only physiologically in response to energy constraints but also psychologically, via recognition of food availability.


Assuntos
Alimentos , Murinae/fisiologia , Murinae/psicologia , Torpor , Animais , Tamanho Corporal , Feminino , Masculino , Fatores de Tempo
9.
Biol Pharm Bull ; 37(6): 922-5, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24882405

RESUMO

We recently found that hepatic triglyceride lipase (HTGL) was released from primary cultured rat hepatocytes after treatment with prazosin, an antagonist of alpha-1 adrenoceptors. However, the details of prazosin-induced HTGL release remain uncertain. Here we investigated whether changes in cAMP levels in hepatocytes were related to HTGL release from prazosin-stimulated hepatocytes. When hepatocytes were treated with prazosin, cAMP levels during stimulated release of HTGL increased in a time- and dose-dependent manner. Stimulated release of HTGL was suppressed by the adenylate cyclase inhibitors MDL-12,330A and 2',5'-dideoxyadenosine. Further, cAMP-dependent protein kinase A (PKA) activity in prazosin-stimulated hepatocytes also increased in a time- and dose-dependent manner. Moreover, prazosin-stimulated HTGL release was suppressed by the PKA inhibitors H-89 and KT5720. These results suggest that prazosin-stimulated HTGL release from hepatocytes was due to cAMP production and partly due to subsequent PKA activation in hepatocytes.


Assuntos
Antagonistas de Receptores Adrenérgicos alfa 1/farmacologia , AMP Cíclico/metabolismo , Hepatócitos/efeitos dos fármacos , Lipase/metabolismo , Fígado/efeitos dos fármacos , Prazosina/farmacologia , Animais , Técnicas de Cultura de Células , Células Cultivadas , Relação Dose-Resposta a Droga , Hepatócitos/enzimologia , Hepatócitos/metabolismo , Fígado/enzimologia , Fígado/metabolismo , Masculino , Ratos Wistar , Fatores de Tempo
10.
Physiol Behav ; 133: 22-9, 2014 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-24813827

RESUMO

Small endotherms employ multiple adaptations to maintain energy balance in winter, including spontaneous daily torpor and simultaneous huddling. The relationships between these adaptations have been discussed in several previous studies, but it has not been well-established if huddling actually affects the expression of torpor in small endotherms. We examine whether and how huddling affects the expression of torpor in the large Japanese field mouse Apodemus speciosus, which is known to become torpid under artificial winter conditions. The mice were found to adjust expression of torpor in response to the number of cage mates. Torpor frequency and minimum torpid body temperature were both significantly elevated when the number of cage mates was increased, but there was no significant change in torpor bout length. Rewarming rate on arousal was lower when the number of cage mates was increased, suggesting reduction in endogenous rewarming due to exogenous passive rewarming. Food consumption per mouse decreased significantly with increasing number of cage mates. Thus, our study demonstrates that social thermoregulatory behaviors such as huddling can facilitate expression of spontaneous daily torpor in small rodents. These findings suggest that energy constraints, such as ambient temperature and food availability may not be the only modulating factors on the expression of daily torpor.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Metabolismo Energético/fisiologia , Torpor/fisiologia , Aclimatação/fisiologia , Animais , Ingestão de Alimentos , Feminino , Masculino , Camundongos , Fatores Sexuais , Fatores de Tempo
11.
Virus Genes ; 48(3): 448-56, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24469466

RESUMO

Ecotropic murine leukemia viruses (Eco-MLVs) infect mouse and rat, but not other mammalian cells, and gain access for infection through binding the cationic amino acid transporter 1 (CAT1). Glycosylation of the rat and hamster CAT1s inhibits Eco-MLV infection, and treatment of rat and hamster cells with a glycosylation inhibitor, tunicamycin, enhances Eco-MLV infection. Although the mouse CAT1 is also glycosylated, it does not inhibit Eco-MLV infection. Comparison of amino acid sequences between the rat and mouse CAT1s shows amino acid insertions in the rat protein near the Eco-MLV-binding motif. In addition to the insertion present in the rat CAT1, the hamster CAT1 has additional amino acid insertions. In contrast, tunicamycin treatment of mink and human cells does not elevate the infection, because their CAT1s do not have the Eco-MLV-binding motif. To define the evolutionary pathway of the Eco-MLV receptor, we analyzed CAT1 sequences and susceptibility to Eco-MLV infection of other several murinae animals, including the southern vole (Microtus rossiaemeridionalis), large Japanese field mouse (Apodemus speciosus), and Eurasian harvest mouse (Micromys minutus). Eco-MLV infection was enhanced by tunicamycin in these cells, and their CAT1 sequences have the insertions like the hamster CAT1. Phylogenetic analysis of mammalian CAT1s suggested that the ancestral CAT1 does not have the Eco-MLV-binding motif, like the human CAT1, and the mouse CAT1 is thought to be generated by the amino acid deletions in the third extracellular loop of CAT1.


Assuntos
Transportador 1 de Aminoácidos Catiônicos/genética , Evolução Molecular , Vírus da Leucemia Murina/fisiologia , Muridae/genética , Receptores Virais/genética , Infecções por Retroviridae/virologia , Doenças dos Roedores/virologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Arvicolinae , Transportador 1 de Aminoácidos Catiônicos/química , Transportador 1 de Aminoácidos Catiônicos/metabolismo , Linhagem Celular , Cricetinae , Gerbillinae , Humanos , Camundongos , Dados de Sequência Molecular , Muridae/classificação , Muridae/virologia , Filogenia , Ratos , Receptores Virais/química , Receptores Virais/metabolismo
12.
Mar Genomics ; 7: 27-31, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22897959

RESUMO

We constructed ammonia monooxygenase alpha subunit (amoA) gene clone libraries of ammonia-oxidizing archaea (AOA) and bacteria (AOB) from three biofiltration tanks used for closed marine fish culture systems. The number of operational taxonomic units (OTUs) found in any one place was 76%-80% of the total OTUs in each tank for AOA and 100% for AOB when OUTs were defined on the basis of a 5% nucleotide difference. In a phylogenetic tree, all of the AOA amoA sequences fell into a cluster, which contained Candidatus Nitrosopumilus maritimus. All of the AOB amoA sequences were related to the Nitrosospira lineage. These results indicated that different ammonia oxidizers were present in different tanks, but that the dominant phylogenetic types were stable. In a biofiltration tank to which a high concentration of ammonium chloride was added periodically to condition the biofilter materials, most of the AOA amoA sequences were different from the dominant one observed in the fish culture tanks. The AOB amoA sequences were also different, and were similar to those of Nitrosomonas aestuarii. These findings suggest that high concentration ammonia loads have a considerable affect on ammonia-oxidizer community composition.


Assuntos
Aquicultura/instrumentação , Archaea/enzimologia , Bactérias/enzimologia , Filtração/instrumentação , Oxirredutases/genética , Filogenia , Microbiologia da Água , Amônia/análise , Sequência de Bases , Clonagem Molecular , Análise por Conglomerados , Primers do DNA/genética , Biblioteca Gênica , Dados de Sequência Molecular , Subunidades Proteicas/genética , Água do Mar/química , Água do Mar/microbiologia , Análise de Sequência de DNA
13.
Zygote ; 20(3): 249-59, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21729376

RESUMO

In the present study, we investigated the effects of various concentrations of cysteine (0.0, 0.6, 1.2 and 1.8 mM) added to the maturation medium on nuclear maturation and subsequent embryonic development of bovine oocytes exposed to heat stress (HS: set at 39.5 °C for 5 h, 40.0 °C for 5 h, 40.5 °C for 6 h, and 40.0 °C for 4 h versus 38.5 °C for 20 h as the control group). This regime mimicked the circadian rhythm of the vaginal temperature of lactating dairy cows during the summer season in southwestern Japan. Moreover, we also evaluated the oocyte's reactive oxygen species (ROS) and glutathione (GSH) levels and the apoptosis levels of the oocytes and cumulus cells in the presence or absence of 1.2 mM cysteine. As a result, HS in the without-cysteine group significantly suppressed (p < 0.05) both the nuclear maturation rate up to the metaphase (M)II stage and the blastocyst formation rate compared with that of the control group. In addition, this group showed significantly higher (p < 0.05) ROS levels and significantly lower (p < 0.05) GSH levels than those of the control group. Moreover, the level of TdT-mediated dUTP nick end labelling (TUNEL)-positive cumulus cells in the HS without-cysteine group was significantly higher (p < 0.05) than that of the control group. However, the addition of 1.2 mM cysteine to the maturation medium restored not only the nuclear maturation, blastocyst formation rates and GSH contents, but also increased the ROS and TUNEL-positive levels of the cumulus cells, but not oocytes, to that of the control group. These results indicate that the addition of 1.2 mM cysteine during in vitro maturation (IVM) may alleviate the influence of heat stress for oocyte developmental competence by increasing GSH content and inhibiting the production of oocyte ROS followed by apoptosis of cumulus cells.


Assuntos
Apoptose , Cisteína/farmacologia , Glutationa/metabolismo , Resposta ao Choque Térmico , Oócitos/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Animais , Bovinos/embriologia , Relação Dose-Resposta a Droga , Desenvolvimento Embrionário , Feminino , Fertilização In Vitro , Marcação In Situ das Extremidades Cortadas , Oócitos/crescimento & desenvolvimento
14.
Mol Reprod Dev ; 79(1): 31-40, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22128015

RESUMO

This study was undertaken to investigate the effects on the nuclear maturation and subsequent embryonic development of bovine oocytes exposed to heat stress (HS) when treating bovine oocytes before in vitro maturation (IVM) with 1 µM cyclosporin A (CsA), an inhibitor of mitochondrial permeability transition pore opening. Mitochondrial activity, reactive oxygen species (ROS), and apoptosis levels of the oocytes were also assessed. Nuclear maturation rates of both the HS-exposed oocytes treated with or without CsA groups (HS + CsA or HS group) were significantly lower (P<0.05) than that of the control group, while the rate of the HS + CsA group was significantly higher (P<0.05) than that of the HS group. Furthermore, although the cleavage and blastocyst formation rates of the HS group were significantly lower than those of the control groups (P<0.05), both rates of the HS + CsA group recovered to the same level as those of the control group. The HS group showed a significantly higher ROS level, lower mitochondrial activity in the oocytes, and TUNEL-positive cumulus cells, but not oocytes, compared with those of the control group (P<0.05), whereas the TUNEL-positive and mitochondrial activity levels of the HS + CsA group recovered to those of the control group. These results indicate that 1 µM CsA treatment before IVM may mitigate reduced mitochondrial activity, increase number of apoptotic cumulus cells under HS, and improve the nuclear maturation and developmental competence of bovine oocytes.


Assuntos
Ciclosporina/farmacologia , Resposta ao Choque Térmico/efeitos dos fármacos , Resposta ao Choque Térmico/fisiologia , Oócitos/efeitos dos fármacos , Oócitos/fisiologia , Animais , Apoptose/efeitos dos fármacos , Blastocisto/efeitos dos fármacos , Bovinos , Núcleo Celular/efeitos dos fármacos , Células do Cúmulo/efeitos dos fármacos , Marcação In Situ das Extremidades Cortadas , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Membranas Mitocondriais/efeitos dos fármacos , Oócitos/citologia , Espécies Reativas de Oxigênio/metabolismo
15.
J Reprod Dev ; 57(4): 450-6, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21478652

RESUMO

In the present study, we investigated the relationship between the temperature-humidity index (THI) and the conception rate of lactating dairy cows in southwestern Japan, one of the hottest areas of the country. We also investigated the relationship between measurement of the vaginal temperature of lactating dairy cows as their core body temperature at one-hour intervals for 25 consecutive days in hot (August-September, n=6) and cool (January-February, n=5) periods and their THI. Furthermore, we discussed the above relationship using these vaginal temperatures, the conception rates and the THI. As a result, when the conception rates from day 2 to 0 before AI were classified into day 2, 1 and 0 groups by the six maximum THI values in each group (mTHI; <61, 61-65, 66-70, 71-75, 76-80, >80), only the conception rate for the mTHI over 80 at 1 day before AI group was significantly lower (P<0.05) than the other groups. The conception rate for days 15 to 17, but not days 19 to 22 and 30 to 35, after AI in the cows that experienced average mTHI over 80 (amTHI>80) was significantly lower (P<0.05) than that of the cows that did not experience amTHI>80. There was a significant positive correlation (P<0.01) between the mTHI and the mean daily vaginal temperature, but not during the cool period. When the mTHI reached 69, the vaginal temperature started to increase. As for the relationship between the conception rates and vaginal temperatures for all mTHI classes, in the mTHI>80 at 1 day before AI group, the vaginal temperature increased by 0.6 C from 38.7 C, resulting in a reduction of 11.6% in the conception rate from 40.5%. In conclusion, these results suggest that one of the causes of the fall in conception rate of lactating dairy cows during the summer season in southwestern Japan may be an increase in their core body temperature with a higher mTHI than the critical mTHI of 69 at 1 day before AI.


Assuntos
Temperatura Corporal , Fertilização , Animais , Bovinos , Ritmo Circadiano , Indústria de Laticínios/métodos , Feminino , Umidade , Inseminação Artificial/métodos , Japão , Lactação , Gravidez , Estações do Ano , Temperatura , Fatores de Tempo , Vagina/patologia
16.
Cryobiology ; 58(3): 303-7, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19268658

RESUMO

This study is the first attempt at sperm cryopreservation, as well as a further examination of frozen sperm fertility by the hamster test, applied to the maintenance of an Indian gerbil (Tatera indica) colony, which is a newly developing experimental animal. The osmotic tolerance of the spermatozoa was initially investigated by subjection to hypertonicity, up to 620mOsm/kg, for 5min at room temperature prior to freezing. Although the percentage of total motile sperm was not affected, that of progressive motile spermatozoa began to drop at 400mOsm/kg, and a significant decrease was observed at 620mOsm/kg (p<0.01). According to these results, the osmolality of the solutions for the freezing experiment, in which 6-22% raffinose was present, was fixed at approximately 400mOsm/kg. Sperm, suspended in a plastic straw, were frozen in liquid nitrogen vapor for 5min, followed by immersion in liquid nitrogen. Motile sperm were recovered from all freezing conditions, and high survival was obtained when sperm were frozen in the presence of 14% and 18% raffinose, with a normalized motility higher than 40%. Fertility of cryopreserved Indian gerbil sperm was examined by the zona-free hamster test. Thawed sperm adhered to 88% of the zona-free hamster oocyte surface, and some oocytes were penetrated and exhibited swollen sperm heads or male pronuclei, which we used to define fertilization. Although the fertilization rate of cryopreserved sperm to zona-free hamster eggs was significantly lower than that of fresh sperm (6% vs. 30%, p<0.01), we demonstrated that thawed Indian gerbil spermatozoa have the ability to maintain their fertility.


Assuntos
Criopreservação/métodos , Fertilidade , Preservação do Sêmen/métodos , Espermatozoides , Animais , Cricetinae , Feminino , Gerbillinae , Masculino , Osmose , Motilidade Espermática/fisiologia , Interações Espermatozoide-Óvulo , Espermatozoides/fisiologia
17.
Comp Immunol Microbiol Infect Dis ; 32(5): 395-406, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18249443

RESUMO

Measles virus (MeV) vaccine strain, AIK-C, is temperature sensitive (ts), which is thought to be associated with attenuation of virus pathogenicity. In this study, replication and antibody response were examined in cotton rats using viruses carrying different forms of the P gene, which is responsible for the ts phenotype of strain AIK-C and its parental Edmonston strain. When cotton rats were inoculated intranasally, ts viruses neither replicated in lungs, nor reproducibly generated an antibody response. When inoculated intramusculary (i.m.), however, ts strains raised an antibody titer in all animals. This response was not observed when ultraviolet-inactivated virus was used. ts virus, inoculated i.m., was recovered from cotton rat drainage lymph nodes. These results suggest that ts virus, inoculated i.m., could replicate in the cotton rat, presumably at the superficial lymph node, and induce an antibody response. Therefore, cotton rats can serve as a small-animal model for investigating immune responses to safer ts vaccine, as well as recombinant vaccine using AIK-C as a vector for protection against other infectious agents.


Assuntos
Linfonodos/imunologia , Vacina contra Sarampo/imunologia , Vírus do Sarampo/imunologia , Sigmodontinae/imunologia , Animais , Formação de Anticorpos/imunologia , Linhagem Celular , Células Cultivadas , Modelos Animais de Doenças , Feminino , Pulmão/imunologia , Pulmão/virologia , Linfonodos/virologia , Sigmodontinae/virologia , Temperatura , Replicação Viral/imunologia
18.
Mamm Genome ; 19(3): 155-62, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18299925

RESUMO

Genetic characterization of a wild-derived house mouse, Mus musculus, originally collected near Lake Balkhash in the Republic of Kazakhstan, was performed by examining protein polymorphisms and nucleotide sequences for the hemoglobin beta chain (HBB) subunits. Protein electrophoresis, which was performed on a cellulose-acetate plate, showed an independent mobility pattern representing a new, previously undiscovered haplotype. Neighbor-joining analyses of the HBB adult genes, i.e., HBB-T1 and HBB-T2, and the intergenic spacer region showed that the Lake Balkhash mouse possessed genomic components that were mixed from different haplotypes. Compared to the previously determined HBB haplotypes, d, p, and w1, the HBB-T1 gene and ca. 11 kb of the spacer region were most similar to the w1 haplotype; however, the remainder of the spacer region and the HBB-T2 gene were most similar to the d haplotype but may represent a still uncharacterized and divergent haplotype. The recombination event is predicted to have occurred 2.5 kb upstream of the HBB-T2 gene and may have occurred through intersubspecific hybridization between mice of the musculus subspecies group (with the w1 haplotype) and the castaneus subspecies group (with the d-like haplotype). Alternatively, an unknown subspecies group that is equidistantly divergent from each of these subspecies groups may have been involved. Our findings suggest reticulate evolution among the subspecies groups during the evolution of M. musculus.


Assuntos
Globinas/genética , Haplótipos , Animais , DNA Intergênico , Cazaquistão , Camundongos , Polimorfismo Genético , Subunidades Proteicas/genética , Recombinação Genética , Especificidade da Espécie
19.
Biol Pharm Bull ; 28(3): 409-12, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15744060

RESUMO

The release of hepatic lipase (HTGL), which is responsible for the hydrolysis of lipoprotein triacylglyceride, produced by heparin from the isolated rat hepatocytes in primary culture has been examined. Tyrosine kinase (TK) inhibitors (ST-638 and biochanin A) inhibited the heparin-stimulated release of HTGL activity. The activity of partially purified TK preparation from the hepatocytes was found to be increased following incubation with heparin in a manner which was both time- and dose-dependent. An intracellular Ca(2+)-chelator (Quin2/AM), a calmodulin inhibitor (W-7) and a Ca(2+)/calmodulin-dependent protein kinase II (CaMK-II) inhibitor (KN-93) suppressed the release of HTGL activity by heparin. In addition, CaMK-II activity in the hepatocytes incubated with heparin was recognized to elevate in a time- and dose-dependent manner. The increase in CaMK-II activity by heparin was markedly reduced in the presence of the inhibitors of TK. These results suggest that the release of HTGL activity from the hepatocytes by heparin is, in part, caused through a pathway involving an activation of CaMK-II associated with an increase in membrane TK activity.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/fisiologia , Heparina/farmacologia , Hepatócitos/enzimologia , Hepatócitos/metabolismo , Lipase/metabolismo , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Proteínas Quinases Dependentes de Cálcio-Calmodulina/antagonistas & inibidores , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Hepatócitos/efeitos dos fármacos , Lipase/antagonistas & inibidores , Fígado/efeitos dos fármacos , Fígado/enzimologia , Fígado/metabolismo , Masculino , Ratos , Ratos Wistar
20.
Biol Pharm Bull ; 27(6): 789-96, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15187419

RESUMO

Orthovanadate (vanadate) as well as insulin stimulated phosphodiesterase 3 (PDE3) in the particulate fraction of rat hepatocytes. The vanadate-induced activations of PDE3 and mitogen-activated protein kinase (MAPK) were inhibited by H-89 and PD98059, suggesting that the MAPK activation via cAMP-dependent protein kinase (PKA) and MAPK kinase is involved in the vanadate action. On the other hand, the insulin-induced activations of PDE3 and Akt were inhibited by wortmannin, suggesting involvement of the Akt activation via phosphatidylinositol 3-kinase (PI3K) in the insulin action. The vanadate-induced activations of PKA and PDE3 were inhibited in part by propranolol or genistein, suggesting that vanadate may exert its actions via dual signaling pathways of beta-adrenergic receptors and receptor tyrosine kinases of growth factors. Vanadate, in contrast to insulin, did not promote the phosphorylation of insulin receptor substrate-1. The vanadate-induced increase in the phosphorylation of a main isoform of MAPKs, p44 protein, was detected by immunoblotting migration patterns of SDS-PAGE. A partially purified PDE3 activity was increased by addition of MAPK or Akt to the reaction mixture, suggesting that MAPK as well as Akt acts upstream of PDE3. The activation of PDE3 by insulin was independent of a transient increase in the MAPK activity, probably due to the dephosphorylated inactivation mediated by the induced activation of MAPK phosphatases (MKPs). Vanadate did not affect the MKP activity. These results indicate that vanadate stimulates the particulate PDE3 activity by activating mainly p44 MAPK via a PKA-dependent process, and that it differs from insulin with regard to a phosphorylation cascade of PDE3 activation.


Assuntos
3',5'-AMP Cíclico Fosfodiesterases/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Hepatócitos/efeitos dos fármacos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Vanadatos/farmacologia , Animais , Células Cultivadas , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3 , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Hepatócitos/enzimologia , Insulina/farmacologia , Masculino , Ratos , Ratos Wistar
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