二叠纪腕足动物地理区系演化特征

建立系统、完善的二叠纪腕足动物地层、地理信息资料库、选用聚类分析等方法,进行古生物地理区系的定量研究,从时空两方面探讨了二叠纪腕足动物地理区系的划分和演变,分４个世详细论述了二叠纪腕足动物的世界分区及其与泛大陆演化的关系。     

中国古生物学会四川、西藏联合组成立大会暨第一次学术讨论会与龙门山泥盆系现场会议同时在四川江油举行

中国古生物学会浙江组于6月3-5日在桐庐冷坞召开了"石炭、二叠纪地层剖面现场讨论会."浙江石油地质研究所有关同志在会议上介绍了他们多年来对冷坞剖面工作的成果.冷坞石炭、二叠纪地层剖面露头发育良好,层序齐全,界线较清晰;?、珊瑚、苔藓虫、腕足类等生物化石丰富,是浙江中部研究石炭、二叠纪地层的重要剖面之一.     

关于申报中国古生物学会第5届"尹赞勋地层古生物学奖"的通知

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中国古生物学会1989年学术活动计划

学术会议 中国古生物学会昆明组学术交流会-- 甲壳类学科组第二届学术年会 腕足动物学科组第三次学术年会 中国古生物学会第十五届学术年会 第二届青年古生物工作煮学术交流会 花粉资源利用开发学术讨论会 大羽羊齿植物群及相关地层学术讨论会 华东地区地层、古生物学及相关学科学术交流会 古生物、古环境和沉积矿产关系学术讨论会!时.间_…_会议地色一一 1)J 3月 4月jJ 18一24日 9月 待定 待定 11)J 11)J昆明昆明宜吕武汉南京上海福建福建成都中国古生物学会1989年学术活动计划     

中国古生物学会第八届全国会员代表大会暨第二十一次学术年会在西安召开

２００１年５月１９日至２２日 ,中国古生物学会第八届全国会员代表大会暨第二十一次学术年会在古都陕西西安隆重举行。这是新世纪我国古生物学者的第一次全国性聚会 ,来自各行业的１７０余名古生物地层学及相关领域的工作者出席了这次盛会。会议期间 ,与会代表进行了广泛的学术交流 ,共有１２人作大会报告 ,４２人作分会报告。内容涉及古生物学及地层学研究的各个领域 ,从早期生命演化到重要生物类群的起源 ,从生物地层对比到地史时期的环境演变 ,从基础理论研究到生产中的实际应用 ,等等。其中 ,有关澄江动物群、热河生物群以及关岭动物群…     

《古生物学报》征稿简则北大核心CSCD

本刊是古生物学及其相关的生物地层学综合性学术刊物,主要刊载古生物学及其相关学科原创性研究论文、学科动态、学术讨论、论著评述以及新技术、新方法的应用等。为进一步提高《古生物学报》的学术质量,特作如下稿约。     

《古生物学报》征稿简则北大核心CSCD

本刊是古生物学及其相关的生物地层学综合性学术刊物,主要刊载古生物学及其相关学科原创性研究论文、学科动态、学术讨论、论著评述以及新技术、新方法的应用等。为进一步提高《古生物学报》的学术质量,特作如下稿约。     

《古生物学报》征稿简则北大核心CSCD

本刊是古生物学及其相关的生物地层学综合性学术刊物,主要刊载古生物学及其相关学科原创性研究论文、学科动态、学术讨论、论著评述以及新技术、新方法的应用等。为进一步提高《古生物学报》的学术质量,特作如下稿约。     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.