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1.
郑淑英 《古生物学报》1995,34(6):722-730
描述的介形类化石标本采集于新疆塔里木盆地库车和喀什两地区,其中,齐古组产Darwinula-Timiriasevia组合,恰克马克组产Darwinula-Bisulcocypris为代表的介形类化石组合,其时代前者为晚侏罗世,后者为中侏罗世;俄霍布拉克组和克拉玛依组产以Bisulcompris-TungchuaniaDarwinula为代表的组合,其时代为早-中三叠世。  相似文献   

2.
吐鲁番盆地鄯善地区中、晚侏罗世介形类   总被引:1,自引:0,他引:1  
报道吐鲁番盆地连木沁剖面七克以组及齐古组的介形类化石3属10种,其中2新种1未定种;Theriosynoecum?qiktimensis sp.no。,Th.huoyanshanenis sp.nov.,Darwinula sp.,根据化石组合面貌,自上而下可建立两个组合,即Darwinula-Metacypris组合和Theriosynoecum?-Darwinula组合,其时代分别为晚侏罗世和  相似文献   

3.
腾格里沙漠晚更新世湖相沉积介形类及其环境意义   总被引:4,自引:0,他引:4  
腾格里沙漠晚更新世断头梁剖面分析出介形类7属7种,分别为Limnocythereinopinata,Darwinulastevensoni,Candonaneglecta,Cyprideistorosa,Ilyocyprisgibba,Cyclocyprisserena,?Neocypridopsissp.,其中Limnocythereinopinata和Darwinulastevensoni为优势种。根据丰度、分异度及百分含量变化情况,研究剖面划分出四个介形类组合,进一步结合年代数据、沉积物及孢粉资料识别出四个气候期。距今约42000-23000年间研究区总的气候特征是温暖湿润,间有几次幅度较小的变冷期;介形类显示出淡水至中盐水环境,这一特征持续整个沉积时期,没有出现干旱期。  相似文献   

4.
滕格里沙漠晚更新世湖相沉积介形类及其环境意义   总被引:2,自引:0,他引:2  
腾格里沙漠晚更新世断头梁剖面分析出介形类7属7种,分别为Limnocythere inopinata,Darwinula stevensoni,Candona neglecta,Cyprideis torosa,Ilyocypris gibba,Cyclocypris serena,?Neocypridopsis sp.,其中Limnocythere inopinata和Darwinula ste  相似文献   

5.
塔里木盆地北缘侏罗纪孢粉组合   总被引:17,自引:6,他引:11  
本文系统地研究了塔里木盆地北缘侏罗纪的孢子花粉。共发现孢粉化石52属90种,以及藻类化石2属2种。建立侏罗纪的孢粉组合序列如下:(1)Disacciatrileti-Cyathidites组合(早侏罗世早期阿合组),(2)Cyathidites-Cibotiumspora-Disacciatrileti组合(早侏罗世晚期阳霞组),(3)Cyathidites-Neoraistrickia-Disacciatrileti组合(中侏罗世早期克孜勒努尔组),(4)Cyathidites-Clasopolis组合(中侏罗世晚期恰克马克组)。根据孢粉组合特征讨论了地质时代,同时探讨了古植被和古气候的意义。  相似文献   

6.
塔里木盆地北部早白垩世孢粉组合   总被引:9,自引:0,他引:9  
根据建组部面和4个钻井剖面舒善河组孢粉化石的研究,建立5个孢粉组合,自老而新为Classopollis-Schizaeoisporites组合,Classopollis高含量组合,Classopollis-Dicheiropollis组合,Classopollis-Dicheiropollis-Lygodium-sporites组合和Dicheiropollis高含量组合。根据舒善河组的时代为早白  相似文献   

7.
刘兆生 《微体古生物学报》2000,17(4):443-450,T019,T021
通过对新疆克拉玛依地区吐孜阿克内沟剖面三工河组孢粉组合的研究,共鉴定孢粉23属32种,藻类化石2属4种,命名为Disacciatrileti-Monocolpates-Cyathidites组合(简称DMC组合)。描述了5种花粉Abietineaepollenites dunrobinensis Couper,Pseudopicea monstruosa Bolch.,Podocarpidites  相似文献   

8.
孙元林 《古生物学报》1997,36(4):485-493
描述青海贵德盆地万秀群中段的介形类5属14种,其中Cypridea wanxiuensis为新种。这些介形类代表了典型的早白垩世组合。结合孢粉分析结果在该地区存在典型热河动物群分子(如Eosestheria cf.persculpta,E.spp.,Diestheria sp.和Ephemeropso trisetalis等),认为万秀群中段含介表类层段的地质时代大体相当于白垩纪早期的Berris  相似文献   

9.
西沙群岛西琛一井中新世地层,古生物群和古环境研究   总被引:3,自引:0,他引:3  
根据壳状珊瑚藻、海相底栖介形类和有孔虫资料,西琛一井井深346.92-802.17m的地层分别被归为下中新统西沙组下段(井深550-802.17m)和上段(431-550m),中中新统宣德组(353.40-431m)。西沙组下段包括3个介形类组合,自下而上为:①Aurila xishaensis-Tenedocythere xishaensis,②Tenedocythere xishaensis-  相似文献   

10.
民和盆地的甘肃兰州柴家台地区,下白垩统河口组上亚组含有丰富的孢粉化石。上亚组上部是以Schizaeoisporites-Cicatricosis porites为代表的粉组合,并可划分出上下两个亚组合,分别以Classopollis-Schizaeoisporites和Piceapollenites-Cicatricosisporites来表示。  相似文献   

11.
Aquaporins: water channel proteins of the cell membrane   总被引:37,自引:0,他引:37  
Aquaporins (AQP) are integral membrane proteins that serve as channels in the transfer of water, and in some cases, small solutes across the membrane. They are conserved in bacteria, plants, and animals. Structural analyses of the molecules have revealed the presence of a pore in the center of each aquaporin molecule. In mammalian cells, more than 10 isoforms (AQP0-AQP10) have been identified so far. They are differentially expressed in many types of cells and tissues in the body. AQP0 is abundant in the lens. AQP1 is found in the blood vessels, kidney proximal tubules, eye, and ear. AQP2 is expressed in the kidney collecting ducts, where it shuttles between the intracellular storage sites and the plasma membrane under the control of antidiuretic hormone (ADH). Mutations of AQP2 result in diabetes insipidus. AQP3 is present in the kidney collecting ducts, epidermis, urinary, respiratory, and digestive tracts. AQP3 in organs other than the kidney may be involved in the supply of water to them. AQP4 is present in the brain astrocytes, eye, ear, skeletal muscle, stomach parietal cells, and kidney collecting ducts. AQP5 is in the secretory cells such as salivary, lacrimal, and sweat glands. AQP5 is also expressed in the ear and eye. AQP6 is localized intracellular vesicles in the kidney collecting duct cells. AQP7 is expressed in the adipocytes, testis, and kidney. AQP8 is expressed in the kidney, testis, and liver. AQP9 is present in the liver and leukocytes. AQP10 is expressed in the intestine. The diverse and characteristic distribution of aquaporins in the body suggests their important and specific roles in each organ.  相似文献   

12.
啮齿动物作用下退耕地山杏种子扩散与贮藏的季节变化   总被引:2,自引:0,他引:2  
啮齿动物对植物种子的取食和扩散影响种子的时空分布,继而影响种子的萌发和幼苗建成,因而在森林更新中起着重要作用.在国有济源市愚公林场,选择退耕地生境,于春季、夏季、秋季分别释放人工标记的山杏种子,观察啮齿动物扩散与埋藏山杏种子的季节性差异.结果表明:1)退耕地中的啮齿动物主要包括大林姬鼠、社鼠、黑线姬鼠;2)山杏种子扩散速率在春季显著慢于夏季,夏季显著慢于秋季;3)种子搬运量受季节和种子状态交互作用影响,春季显著少于夏季,夏季显著少于秋季;4)不同季节种子平均搬运距离不同,秋季不同状态种子的搬运距离均大于春季和夏季;5)啮齿动物对山杏种子的贮藏点大小多为1粒种子,少量为2、3粒种子,且贮藏点大小与季节间存在显著的交互作用,春季单粒种子的贮藏点数量显著少于夏季和秋季,而夏季与秋季的贮藏点则倾向于多粒种子;6)在夏季和秋季各有5枚(共释放1800枚)被啮齿动物分散贮藏的山杏种子建成幼苗.  相似文献   

13.
It is noteworthy that in the rat the early postnatal life is marked by an activation of both the corticostimulating function of the adenohypophysis in neonates of both sexes and of the gonadostimulating function mainly in males. In order to specify if such neuroendocrine variations are temporally correlated with changes in the hypothalamic metabolism of neurotransmitters, the hypothalamic metabolism of serotonin (5 HT), norepinephrine (NE), and dopamine (DA) and the hypothalamic content of neuropeptide Y (NPY) have been investigated in newborn rats of both sexes, delivered at term by cesarean section, as well as changes in the activity of both the hypothalamo-pituitary adrenal axis (HPA) and the hypothalamo-pituitary gonadal axis (HPG). Experimental data suggested that 1) in males a rise in hypothalamic metabolism of 5 HT, NE and DA occurs during the first two hours after delivery, whereas in females, only the metabolism of NE increases. Moreover, the postnatal metabolism of NE was higher in females than in littermate males; 2) NPY content of the hypothalamus, which was at birth significantly higher in males than in females, dropped in the former but not in the latter; 3) in newborn males, an early surge of plasma testosterone occurs, suggesting postnatal activation of the HPG axis; on the other hand, in females, a late and slight increase in plasma estradiol is observed; 4) in early postnatal life, a sex-independent rise in plasma ACTH and adrenal and plasma corticosterone levels suggest a comparable activation of the HPA axis in newborns of both sexes. In conclusion, the early postnatal activation of the corticostimulating function in neonates of both sexes and that of the gonadostimulating function, mainly in males, could be temporally correlated with a rise in the hypothalamic metabolism of two neurotransmitters, 5 HT and NE, and of NPY content. According to our data, a sex-dependent metabolsim of neurotransmitters in the hypothalamus is already apparent in early postnatal life.  相似文献   

14.
The spined soldier bug, Podisus maculiventris, is a generalist predator of insects and has been used in biological control. However, information on the digestion of food in this insect is lacking. Therefore, we have studied the digestive system in P. maculiventris, and further characterized carbohydrases in the digestive tract. The midgut of all developmental stages was composed of anterior, median, and posterior regions. The volumes of the anterior midgut decreased and the median midgut increased in older instars and adults, suggesting a more important role of the median midgut in food digestion. However, carbohydrase activities were predominant in the anterior midgut. In comparing the specific activity of carbohydrases, α‐amylase activity was more in the salivary glands (with two distinct activity bands in zymograms), and glucosidase and galactosidase activities were more in the midgut. Salivary α‐amylases were detected in the prey hemolymph, demonstrating the role of these enzymes in extra‐oral digestion. However, the catalytic efficiency of midgut α‐amylase activity was approximately twofold more than that of the salivary gland enzymes, and was more efficient in digesting soluble starch than glycogen. Midgut α‐amylases were developmentally regulated, as one isoform was found in first instar compared to three isoforms in fifth instar nymphs. Starvation significantly affected carbohydrase activities in the midgut, and acarbose inhibited α‐amylases from both the salivary glands and midgut in vitro and in vivo. The structural diversity and developmental regulation of carbohydrases in the digestive system of P. maculiventris demonstrate the importance of these enzymes in extra‐oral and intra‐tract digestion, and may explain the capability of the hemipteran to utilize diverse food sources.  相似文献   

15.
Digestive enzyme distribution and activity in the digestive tracts of the rabbitfish, Siganus canaliculatus and the sea bass, Lates calcarifer were studied. Quantitative determinations of digestive enzymes in the guts of both fishes showed that they were capable of digesting carbohydrates and proteins in their diet. The carbohydrases, amylase, laminarinase, maltase, sucrase and trehalase were detected in the rabbitfish; their activities being mainly in the stomach, intestine and pyloriccaeca. Amylase, maltase, trehalase and chitinase activities were recorded in the gut of the sea bass, primarily in the intestine and the pyloriccaeca. Their activities were significantly lower than those in the rabbitfish. Proteases (pepsin, chymotrypsin, elastase, leucine aminopeptidase and trypsin) were found in both the rabbitfish and the sea bass. Pepsin activity however, was higher in the sea bass; while trypsin and chymotrypsin activities were higher in the rabbitfish. The activities of the various digestive enzymes in both fishes are discussed in relation to their feeding habits.  相似文献   

16.
Dichoroacetate (DCA) and trichloroacetate (TCA) are by-products formed during chlorination of the drinking water and were found to be hepatotoxic and hepatocarcinogenic in rodents. In this study, the abilities of the compounds to induce oxidative stress and phagocytic activation have been studied in B6C3F1 mice. Groups of mice were administered 300 mg/kg of either DCA or TCA, p.o, and were sacrificed after 6 or 12 h. Peritoneal lavage cells (PLCs) were isolated and assayed for superoxide anion (SA) production, and hepatic tissues were assayed for the production of SA, lipid peroxidation (LP), and DNA-single strand breaks (SSBs). TCA resulted in significant production of SA in the PLCs, and in the production of SA, LP, and DNA-SSBs in the hepatic tissues, 12 h after dosing, as compared with the control. DCA administration, on the other hand, resulted in significant increases in the productions of LP and DNA-SSBs in the hepatic tissues at both time points, and in SA production in PLCs and hepatic tissues, 6 h after dosing. However, DCA-induced increases in SA production in PLC and hepatic tissues declined at the 12-h time point, reaching control level in the hepatic tissues. These results may implicate the contribution of phagocytic activation to the induction of oxidative stress in the hepatic tissues and also the role of SA production in the induction of LP and/or DNA damage in those tissues, in response to the compounds. The results also suggest studying the involvement of these mechanisms in the long-term hepatotoxicity/hepatocarcinogencity of the compounds.  相似文献   

17.
苏春田  唐建生  梁彬 《生态学杂志》2012,31(8):2131-2136
采用雨量器、滤膜法、CO2气体监测管法、标准试片对湘西洛塔不同生态系统降雨量、泥沙量、土壤CO2浓度、溶蚀速度进行了研究。结果表明:森林生态系统降雨量高于灌丛生态系统,观测第一年高6.84mm,第二年高218.08mm,且时间趋向均匀;灌丛生态系统水土流失严重,其泥沙含量是森林生态系统的1.53倍,土壤侵蚀为强度,而森林生态系统为微度;不同深度土壤CO2浓度在森林和灌丛生态系统中具有相同的变化趋势,在春季、秋季、冬季随土层加深而增大,在夏季,随土层加深先减少后增大,但季节变化动态略有差异,森林生态系统不同深度、不同季节土壤CO2浓度均大于灌丛生态系统;从全年土壤CO2浓度对比来看,10、20、40cm处,森林生态系统分别是灌丛生态系统的1.66、1.59和1.90倍;不同深度上,溶蚀速度在森林和灌丛生态系统具有相同的变化趋势,15cm处均大于地面,从同一深度来看,森林生态系统溶蚀速度均大于灌丛生态系统,地面、15cm处溶蚀速度分别是灌丛生态系统的1.11倍、2.57倍,说明森林生态系统具有较好的岩溶效应。  相似文献   

18.
Sex differences in the morphology and function of the hippocampus have been reported in several species, but it is unknown whether a sexual dimorphism exists in glial fibrillary acidic protein (GFAP) expression in the rat hippocampus. We analyzed GFAP immunoreactivity in the hippocampus of intact adult male rats as well as in females during diestrus and proestrus phases of the estrous cycle. We found that in CA1, CA3, and dentate gyrus, GFAP immunoreactivity was higher in proestrus females as compared with males and diestrus females. In CA1, a similar GFAP immunoreactivity was found in males and in diestrus females, but in dentate gyrus, males presented the lowest GFAP content. Interestingly, differences in astrocyte morphology were also found. Rounded cells with numerous and short processes were mainly observed in the hippocampus during proestrus whereas cells with stellate shape with few and long processes were present in the hippocampus of males and diestrus females. The marked sex and estrous cycle-dependent differences in GFAP immunoreactivity density and in astrocyte number and morphology found in the rat hippocampus, suggest the involvement of sex steroid hormones in the sexually dimorphic functions of the hippocampus, and in the change in its activity during the estrous cycle.  相似文献   

19.
The dynamics of growth and the contents of free and bound endogenous IAA, gibberellins (GA), cytokinins (zeatin and its riboside), and ABA in kidney bean plants (Phaseolus vulgaris L., cv. Belozernaya) grown in darkness or in the light was studied. Phytohormones were quantified in 5–15-day-old plants by the ELISA technique. Plant growth and phytohormone content were shown to depend on plant age and the conditions of illumination. During scotomorphogenesis, changes in the biomass and hypocotyl length were highly correlated with the content of GA, whereas during photomorphogeneses, these parameters were correlated with the content of zeatin. In darkness, epicotyl growth displayed a positive correlation with the content of GA, whereas in the light, the correlation was negative. Growth characteristics of the primary leaves were shown to correlate with IAA in darkness and with GA and zeatin in the light. At a low concentration of cytokinins in illuminated leaves, cell divisions occurred, whereas, at the higher cytokinin concentrations, cell expansion occurred. The highest content of GA was characteristic of leaves in the period of growth cessation. ABA accumulated during active leaf and root elongation and biomass increment in the light and during hypocotyl growth in darkness. After plant illumination, the ratio of auxins to cytokinins increased in bean roots and decreased in their epicotyls. Thus, light changed the developmental programs of bean plants, which was manifested in the changed rate and duration of growth of various organs (root, hypocotyl, epicotyl, and leaf). Some mechanisms of light action depended on the contents of IAA, ABA, GA, and cytokinins and the ratios between these phytohormones. Differences between scotonorphogenesis of mono-and dicotyledonous plants are discussed in relation to the levels of phytohormones in them.  相似文献   

20.
目的:研究复合疲劳大鼠血液、肌肉、肝脏和脑中矿物元素代谢变化的影响。方法:将30只大鼠随机分为正常对照组、食物限制组和复合疲劳组。经过5天的实验干预后,提取动物的血液、腓肠肌、肝脏和脑,并利用原子吸收分光光度法测量各组织中的钾(K)、钙(Ca)、镁(Mg)、铁(Fe)、锌(Zn)和铜(Cu)。结果:相对正常对照组和食物限制组,复合疲劳大鼠的肌肉、肝脏和脑中的K(P<0.01)和肝脏中的Fe(P<005)明显升高,血液中的Cu(与正常对照组比较P<0.01,与食物限制组比较P<0.05)明显下降;与对照组相比,复合疲劳大鼠的血液中的K明显升高(P<0.05),血液中的Mg和Zn(P<0.05),肌肉中的Ca、Mg和Zn(PCa<0.05,PMg<0.05,PZn<0.01),肝脏中的Ca和Zn(PCa<0.01,PZn<0.05),以及脑中的Fe、Mg和Zn(PFe<0.05,PMg<0.05,PZn<0.01)明显降低。结论:在复合疲劳状态下,大鼠血液、肌肉、肝脏和脑中的K、Ca、Mg、Fe、Zn和Cu代谢发生变化,可能在疲劳的发生与缓解中发挥作用。  相似文献   

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