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1.
大鳞副泥鳅雄核单倍体的早期发育   总被引:4,自引:0,他引:4  
目前,有关鱼类雄核发育的研究已见于川鲽(Platichthys flesus)、马苏大麻哈鱼(Oncorhynchus masou)、虹鳟(Oncorhynchus mykiss)、红点溪鳟(Salvelinus fontinalis)、鲤鱼(Cyprnus carpio)、尼罗罗非鱼(Oreochromis niloticus)、泥鳅(Misgurnus anguillicaudatus)、斑马鱼(Danio rerio)等(Purdom,1969;Arai et al., 1979; Scheerer et al., 1991; May et al., 1988; Bongers et al., 1994;Grunina et al., 1990; Meyers, 1995; Masaoka et al., 1995; 赵振山等,1998;Corley-Smith et al., 1996).  相似文献   

2.
<正>Rapid and efficient isolation of unknown flanking DNA sequences adjacent to known regions is important for molecular biology research.For this purpose,several PCR-based methods have been reported,including inverse PCR(Uchiyama and Watanabe,2006),ligation-mediated PCR(Yan et al.,2003;Ballester et al.,2005;Wang et al.,2007;Trinh et al.,2012)and randomly primed PCR(Liu and Whittier,1995;Liu et al.,1995;Antal et al."2004;Liu and Chen,2007;Reddy et al.,2008;Wang  相似文献   

3.
利用活体观察和蛋白银染色技术对近年来采自青岛、大亚湾、湛江沿岸水体的10个海洋寡毛类纤毛虫种:侧扁急游虫Strombidium apolatum Wilbert & Song,2005、具头急游虫Strombidium capitatum (Leegaard,1995) Kahl,1932、广东急游虫Strombidium guangdongense Liu,et al.,2016、拟卡氏急游虫Strombidiumparacalkinsi (Lei,et al.,1999) Agatha,2004、拟楔尾急游虫Strombidium parastylifer Song,et al.,2009、铃木急游虫Strombidium suzukii Song,et al.,2009、束腰旋游虫Spirostrombidium cinctum (Kahl,1932) Petz,et al.,1995、杨科夫平游虫Parallelostrombidium jankowski (Song,et al.,2009) Song,et al.,2018、卡尔平游虫Parallelostrombidium kahli (Song,et al.,2009) Song,et al.,2018、最小拟盗虫Strombidinopsis minima (Gruber,1884) Song & Bradbury,1998的形态学开展了比较研究,补充和厘定了有关形态特征、纤毛图式以及性状变异等分类学新信息。  相似文献   

4.
准噶尔盆地荒漠区赤狐的食性分析   总被引:1,自引:0,他引:1  
<正>赤狐(Vulpes vulpes)隶属于哺乳纲、食肉目、犬科、狐属,广泛分布于欧亚大陆、非洲北部和北美大陆,在我国也广布各地(高耀亭等,1987;马世来等,2001)。国内外有关赤狐的研究主要集中在洞穴结构(Nakazono and Ono,1987;贾竞波和萧前柱,1990;贾竞波等,1991;贾竞波和马建章,1992;周文扬和魏万红,1995;张洪海等,1999)和巢域选择等方面(Nakazono and Ono,1987;周文扬和魏万红,1995;张洪海等,1999;Frey and Conover,2006;Keith et al.,2007),而针对赤狐食性的研究主要集中在森林草原或苔原环境,如瑞典(Elmhagen et al.,2002)、立陶宛(Laima,2002)及匈牙利(Lanszki et al.,2006,2007)等。  相似文献   

5.
灵长类动物类固醇激素的研究已经在很多物种间展开(Cariso et al.,1999;Lutz et al.,2000;He et al.,2001;Yan and Jiang,2006;Brandon et al.,2008;Lu et al.,2010;Kim et al.,2012)。特别是对于没有明显发情特征的灵长类动物,类固醇激素的变化可以为它们的繁殖状态提供更多可靠的评估(Fujita et al.,2001)。自然状态下野生动  相似文献   

6.
Qi  Hu-Min  Dai  Yue-E  Chen  Wei  Liu  Qian-Qi 《中国科学:生命科学英文版》2019,62(12):1597-1600
<正>Dear Editor,Bisphenol A (BPA), a common and widely used monomer in the production of polycarbonate plastics and epoxy resin,(Healy et al., 2015; De Filippis et al., 2018) has been defined as an endocrine disrupting chemical (EDC) associated with the etiology of insulin resistance (IR)(Gioiosa et al., 2015;Wei et al., 2017) and metabolic disorders (Padmanabhan et al., 2010; Fang et al., 2015; Balistrieri et al., 2018). However,  相似文献   

7.
正Ribosomes are large RNA and protein complexes that function as the machinery for translation protein synthesis(Boisvert et al.,2007;Ben-Shem et al.,2011;Henras et al.,2015;Khatter et al.,2015;McCann et al.,2015).The eukaryotic ribosome is composed of two subunits,the 60S large subunit(LSU)and the 40S small subunit(SSU),which collectively comprise of four different ribosomal RNA(rRNA)species and more than 70 proteins(Ben-Shem et al.,2011;Henras et al.,2015;Khatter et al.,2015).The LSU contains  相似文献   

8.
正微量元素包括Fe、Cu、Cr、Mn和Zn等,虽含量极微,但具有极重要的生理功能,涉及机体的生长发育、免疫代谢等生命活动过程(Shenkin,2008; Subrahmanyam et al.,2015),也是反映机体新陈代谢及生理功能状况的重要指标(Carpene et al.,2017)。例如Fe元素参与机体氧的运输和贮存(Abbaspour et al.,2014),血清铁被认为是动物营养评估的生化指标(Ganapathy et al.,2011); Cu元素是多种氧化酶的重要组分,参与动物新陈代谢、生长发育等(Desai et al.,2014)。  相似文献   

9.
Dear Editor, CRISPR/Cas9 has revolutionized genome editing technology due to its simplicity and robustness (Mali et al., 2013). Several inducible CRISPR/Cas9 systems recently developed make spatiotemporal genome editing possible (Kon ermann et al., 2013;Balboa et al., 2015;Dow et al., 2015;Zetsche et al., 2015;Liu et al., 2016;Kleinjan et al., 2017;Maji et al.. 2017;Senturk et al., 2017;Lu et al., 2018).  相似文献   

10.
正In the last decade, cotton genomics had great progress in genome assembling(Li et al., 2015; Huang et al., 2020) and agriculturally important locus identification(Du et al., 2018;Ma et al., 2018; Li et al., 2021).Upland cotton(Gossypium hirsutum) is one of the most important cash crops cultivated worldwide. The fiber quality of cotton directly determines its economic value, and therefore enhancing fiber quality is always the primary task in cotton breeding practices(Xia et al., 2019; Huang et al.,2021).  相似文献   

11.
Intravital microscopy of the murine pulmonary microcirculation.   总被引:2,自引:0,他引:2  
Intravital microscopy (IVM) is considered as the gold standard for in vivo investigations of dynamic microvascular regulation. The availability of transgenic and knockout animals has propelled the development of murine IVM models for various organs, but technical approaches to the pulmonary microcirculation are still scarce. In anesthetized and ventilated BALB/c mice, we established a microscopic access to the surface of the right upper lung lobe by surgical excision of a window of 7- to 10-mm diameter from the right thoracic wall. The window was covered by a transparent polyvinylidene membrane and sealed with alpha-cyanoacrylate. Removal of intrathoracic air via a trans-diaphragmal intrapleural catheter coupled the lung surface to the window membrane. IVM preparations were hemodynamically stable for at least 120 min, with mean arterial blood pressure above 70 mmHg, and mean arterial Po(2) and arterial Pco(2) in the range of 90-100 Torr and 30-40 Torr, respectively. Imaged lungs did not show any signs of acute lung injury or edema. Following infusion of FITC dextran, subpleural pulmonary arterioles and venules of up to 50-microm diameter and alveolar capillary networks could be visualized during successive expiratory plateau phases over a period of at least 2 h. Vasoconstrictive responses to hypoxia (11% O(2)) or infusion of the thromboxane analog U-46619 were prominent in medium-sized arterioles (30- to 50-microm diameter), minor in small arterioles <30 microm, and absent in venules. The presented IVM model may constitute a powerful new tool for investigations of pulmonary microvascular responses in mice.  相似文献   

12.
低氧性肺血管收缩反应钝化(blunted Hypoxic Pulmonary Vasoconstriction, bHPV)是高原鼠兔在进化过程中形成的对低氧环境的一种适应性策略。以胎儿期、幼龄期及成年期高原鼠兔和昆明白小鼠为研究对象,对两者的肺组织进行发育生物学、比较组织学和比较组织化学研究,以探讨高原鼠兔bHPV形成的组织形态学基础。结果表明:(1)高原鼠兔各时期肺组织微血管的双层弹性纤维含量均低于25%,无明显肌化现象;(2)高原鼠兔直径10~50 μm、50~100 μm和100~200 μm微血管的中膜肌层厚度与其外径比(MT/ED)随年龄增加而逐渐下降;成年高原鼠兔的肺组织微血管MT/ED10-50显著低于成年昆明白小鼠(P < 0.05),但MT/ED50-100和MT/ED100-200均无明显的种间差异(P > 0.05);(3)在直径10~50 μm直径范围微血管中,高原鼠兔和昆明白小鼠平滑肌细胞数与内皮细胞数的比值(SMC/EC)均随年龄增长呈上升趋势,且高原鼠兔SMC/EC的比值极显著低于同年龄组的昆明白小鼠(P < 0.01)。导致高原鼠兔bHPV发生的组织学基础可能是其肺组织中直径10~50μm微血管平滑肌细胞数量少。  相似文献   

13.
To investigate the effect of alveolar hypoxia onthe pulmonary blood flow-segmental vascular resistance relationship, wedetermined the longitudinal distribution of vascular resistance whileincreasing blood flow during hyperoxia or hypoxia in perfused catlungs. We measured microvascular pressures by the micropipetteservo-null method, partitioned the pulmonary vessels into threesegments [i.e., arterial (from main pulmonary artery to 30- to50-µm arterioles), venous (from 30- to 50-µm venules to leftatrium), and microvascular (between arterioles and venules)segments] and calculated segmental vascular resistance. Duringhyperoxia, total resistance decreased with increased blood flow becauseof a reduction of microvascular resistance. In contrast, duringhypoxia, not only microvascular resistance but also arterial resistancedecreased with increase of blood flow while venous resistance remainedunchanged. The reduction of arterial resistance was presumably causedby arterial distension induced by an elevated arterial pressure duringhypoxia. We conclude that, during hypoxia, both microvessels andarteries >50 µm in diameter play a role in preventing furtherincreases in total pulmonary vascular resistance with increased bloodflow.

  相似文献   

14.
The microvasculature of porcine ovaries, with special regard to the follicles in the interstitial-stromal tissue, was studied by scanning electron microscopy (SEM) of vascular corrosion casts. Porcine ovaries displayed several coiled arteries in the hilus and many branches with small diameters and a tightly spiraling configuration in the cortical areas. However, small arterioles became straight before entering vascular complexes of follicles and finally divided into capillaries. Vascular baskets of various sizes (150-9,900 micro m in diameter) and architecture related to follicles in various developmental stages were observed in the ovarian cortex. Small follicles (150-300 micro m in diameter) began with a polygonal meshwork of a few large capillary meshes and developed to an obvious spherical microvascular network with a thin single layer of capillaries when reaching 500-700 micro m in diameter. The microvascular architecture of follicles 1,000-2,000 micro m in diameter developed further and had a three-layer vascular plexus. With a diameter of more than 2,000 micro m, the microvasculature of antral follicles was arranged as an inner vascular plexus of about 25 micro m, a middle plexus of about 100 micro m, and an outer capillary plexus of about 30 micro m in thickness. The present observations indicate that follicular vascular baskets of diverse sizes and architecture in various developmental stages support the gradual increase of follicular blood flow during follicle growth in the pig.  相似文献   

15.
Light- and electron-microscopic examination of arterioles, venules and capillaries of the eyes of several mammalian species has shown that the microfibrils of ocular elastic tissue attach to microvascular basement membranes throughout the uvea (iris, ciliary body, choroid) and optic nerve. Although described sporadically in prior investigations, this report shows that the connections are a common feature of the mammalian eye. The connections appear most numerous at venules and capillaries and are sparse at arterioles. The connections may provide a mechanism by which perivascular elastic tissue influences microvascular function, e.g. the control of blood pressure in them or their response to changes in intraocular pressure.  相似文献   

16.
In the mammalian ovary, there is a striking difference in the distribution of blood vessels to individual follicles, suggesting that a microvascular network affects the selective growth of oocytes and follicles. In the present study the role of microvascular networks and angiogenic factors on the selective growth of oocytes and follicles was evaluated histologically in fetuses and newborns of ICR strain mice. Apparent selective growth of oocytes and follicles was observed in the ovaries of 1 day old newborns and, at this time, microvascular networks were recognized electronmicroscopically around the follicle that had completed the formation of its follicular structure and contained oocytes more than about 20 μm in diameter. In 3 day old newborns, oocytes more than 30 μm in diameter were detected where blood capillaries were well vascularized. Immunoreactivity to epidermal growth factor (EGF) and a strongly negative charged (colloidal iron-positive) substance (glycosaminoglycans; GAG), which have angiogenic activity, were detected in the ovaries of 3 day or older newborns and were identified more often around growing follicles containing oocytes more than 30 (GAG) and 40 (EGF) μm in diameter. Ovaries removed from 20 day old fetuses and cultured for 4 and 6 days in vitro showed a different distribution of growing follicles. A proportion of oocytes 20.0–24.9 μm in diameter increased during 4 and 6 days of incubation. However, the majority of oocytes did not grow further. These findings indicate that microvascular networks and angiogenic factors are deeply involved in selective oocyte growth beyond approximately 20–30 μm in diameter in mouse ovaries.  相似文献   

17.
In the rat, the spleen is a major site of fluid efflux out of the blood. By contrast, the mesenteric vasculature serves as a blood reservoir. We proposed that the compliance and myogenic responses of these vascular beds would reflect their different functional demands. Mesenteric and splenic arterioles ( approximately 150-200 microm) and venules (<250 microm) from rats anesthetized with pentobarbital sodium were mounted in a pressurized myograph. Mesenteric arterial diameter decreased from 146 +/- 6 to 133 +/- 6 microm on raising intraluminal pressures from 80 to 120 mmHg. This response was enhanced in the presence of N(omega)-nitro-l-arginine methyl ester (l-NAME; 139 +/- 6 to 112 +/- 7 microm). There was no such myogenic response in the splenic arterioles, except in the presence of l-NAME (194 +/- 4 to 164 +/- 4.2 microm). We propose that, whereas mesenteric arterioles exhibit myogenic responses, this is normally masked by NO-mediated dilation in the splenic vessels. The mesenteric venules were highly distensible (active, 184 +/- 15 to 320 +/- 30.9 microm; passive in Ca(2+)-free media, 209 +/- 31 to 344 +/- 27 microm; 4-8 mmHg) compared with the splenic vessels (active, 169 +/- 11 to 184 +/- 16 microm; passive, 187 +/- 12 to 207 +/- 17 microm). We conclude that, in response to an increase in perfusion pressure, mesenteric arterial diameter would decrease to limit the changes in flow and microvascular pressure. In addition, mesenteric venous capacitance would increase. By contrast, splenic arterial diameter would increase, while there would be little change in venous diameter. This would enhance the increase in intrasplenic microvascular pressure and increase fluid extravasation.  相似文献   

18.
Investigators report that local heat causes an increase in skin blood flow consisting of two phases. The first is solely sensory neural, and the second is nitric oxide mediated. We hypothesize that mechanisms behind these two phases are causally linked by shear stress. Because microvascular blood flow, endothelial shear stress, and vessel diameters cannot be measured in humans, bat wing arterioles (26.6 +/- 0.3, 42.0 +/- 0.4, and 58.7 +/- 2.2 microm) were visualized noninvasively on a transparent heat plate via intravital microscopy. Increasing plate temperature from 25 to 37 degrees C increased flow in all three arterial sizes (137.1 +/- 0.3, 251.9 +/- 0.5, and 184.3 +/- 0.6%) in a biphasic manner. With heat, diameter increased in large arterioles (n = 6) by 8.7 +/- 0.03% within 6 min, medium arterioles (n = 8) by 19.7 +/- 0.5% within 4 min, and small arterioles (n = 8) by 31.6 +/- 2.2% in the first minute. Lidocaine (0.2 ml, 2% wt/vol) and NG-nitro-L-arginine methyl ester (0.2 ml, 1% wt/vol) were applied topically to arterioles (approximately 40 microm) to block sensory nerves, modulate shear stress, and block nitric oxide generation. Local heat caused only a 10.4 +/- 5.5% increase in diameter with neural blockade (n = 8) and only a 7.5 +/- 4.1% increase in diameter when flow was reduced (n = 8), both significantly lower than control (P < 0.001). Diameter and flow increases were significantly reduced with NG-nitro-L-arginine methyl ester application (P < 0.05). Our novel thermoregulatory animal model illustrates 1) regulation of shear stress, 2) a nonneural component of the first phase, and 3) a shear-mediated second phase. The time course of dilation suggests that early dilation of small arterioles increases flow and enhances second-phase dilation of the large arterioles.  相似文献   

19.
流溪河水库湖泊区浮游动物大小分布特征   总被引:5,自引:0,他引:5  
林秋奇  韩博平 《生态科学》2006,25(3):207-209
于2001年4月至2002年12月调查了流溪河水库湖泊区浮游动物大小分布特征。轮虫在粒径大小范围为50~160μm内,生物量随着粒径的增大而降低;枝角类(100~512μmESD(等效球体直径))的生物量谱呈‘单峰型’,最大生物量出现在中等大小的粒径组(200~256μm)。桡足类的生物量大约占浮游动物生物量的60%,为水库浮游动物最重要的组成部分;粒径分布范围较宽,覆盖了轮虫和枝角类。总体而言,水库湖泊区浮游动物的生物量谱是一个线性谱,浮游动物生物量随着等效球体粒径的增大而上升,表明在食物链能量流动过程中,大个体比小个体消耗了更多的能量。  相似文献   

20.
It has been assumed for a long time that except for limited areas close to respiratory bronchioles or their satellite arteries, there is no evidence of lymphatic vessels deep in the pulmonary lobule. An immunohistochemical study using the D2-40 monoclonal antibody was performed on normal pulmonary samples obtained from surgical specimens, with particular attention to the intralobular distribution of lymphatic vessels. This study demonstrated the presence of lymphatics not only in the connective tissue surrounding the respiratory bronchioles but also associated with intralobular arterioles and/or small veins even less than 50 μm in diameter. A few interlobular lymphatic vessels with a diameter ranging from 10 μm to 20 μm were also observed further away, in interalveolar walls. In conclusion, this study, using the D2-40 monoclonal antibody, demonstrated the presence of small lymphatic channels within the normal human pulmonary lobules, emerging from interalveolar interstitium, and around small blood vessels constituting the paraalveolar lymphatics. This thin intralobular lymphatic network may play a key pathophysiological role in a wide variety of alveolar and interstitial lung diseases and requires further investigation. (J Histochem Cytochem 57:643–648, 2009)  相似文献   

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