17β-雌二醇对雄性剑尾鱼精巢和肝发育的影响

用组织学的方法研究了50μg/L 17β-雌二醇(E2)持续50 d暴露对剑尾鱼(Xiphophorus helleri)精巢和肝组织结构变化的影响.结果显示,剑尾鱼受E2暴露后,精巢内的精小囊数量减少,精原细胞发育停滞,精子数量稀少甚至没有;肝细胞胞质内出现脂肪空泡和脂肪沉积等脂肪肝症状.结果表明,E2具强雌激素效应,对剑尾鱼精巢和肝组织的损伤具有时间效应,随着暴露时间延长其损伤更严重,但都在其耐受范围之内,未造成鱼体的死亡.精巢组织结构损伤可作为检测水环境雌激素污染生物标记.     

溴氰菊酯连续暴露对罗非鱼血清乙酰胆碱酯酶活性的影响

以罗非鱼为受试生物,研究了不同水温(23℃～27 ℃)对罗非鱼血清中乙酰胆碱酯酶活性的影响,并在此基础上研究了不同浓度(1.0、2.0、3.0、5.0和10.0 μg·L-1)溴氰菊酯暴露下,罗非鱼血清中乙酰胆碱酯酶活性的动态变化.水温分别为23℃和27℃时,乙酰胆碱酯酶的活性分别为(2.75±0.21)和(2.73±0.26)U·ml-1,活性波动范围分别为-12.0%～13.1%和-11.0%～14.2%.水温为(25±1)℃,染毒10 d时,2.0μg·L-1以上浓度的溴氰菊酯对罗非鱼血清中乙酰胆碱酯酶具有明显的抑制作用;染毒20 d时,2.0μg·L-1以上浓度的溴氰菊酯对其抑制率均超过40%;染毒25 d时,5.0 μg·L-1的溴氰菊酯对其抑制率达到最大,为62.3%.实验结果表明:水温在23℃～27℃的波动不会对罗非鱼血清中乙酰胆碱酯酶的活性产生显著影响;水温为(25±1)℃时,高浓度溴氰菊酯(≥2.0 μg·L-1)会对罗非鱼血清中乙酰胆碱酯酶的活性产生抑制作用,而且抑制率随染毒时间的延长呈增加趋势.     

外源激素、温度和亲本规格对大刺鳅人工催产及孵化的影响

综合分析比较了温度、外源激素和亲本规格3种因子对野生大刺鳅(Mastacembelus armatus)人工催产及孵化的影响, 结果显示: 大刺鳅催产及孵化的适宜水温为24—32℃, 最佳繁育水温为28℃, 效应期为(39.43±2.87)—(58.43±1.25)h, 孵化历时为(44.35±0.5)—(75.74±0.63)h, 效应时间和孵化历时随着水温升高逐渐缩短, 呈负相关; 亲本规格直接影响其催产及孵化效果。经外源激素催产后小规格亲本比大规格亲本性腺更早成熟, 催产效益期较短。产卵量、受精率和孵化率3个指标与亲本规格呈正相关, 规格越大产卵量越高卵子质量越好; 在适宜的剂量范围内3种外源激素组合均能部分实现催产。综合分析各项指标, 2种激素混合配方(DOM+LRH–A₂)的催产和孵化效果均较差, 3种外源激素混合使用(HCG+DOM+LRH–A₂)的效果最好, 适合用于大刺鳅繁育, 最佳催产剂量为1000 IU+5 mg+6 μg。     

γ分泌酶抑制剂对肝血窦内皮细胞的影响

目的:在建立高纯度小鼠肝血窦内皮细胞的体外培养的基础上研究γ分泌酶抑制剂(DAPT)对肝血窦内皮细胞活性的影响.方法:首先通过胶原酶灌注消化、percoll梯度离心和选择性贴壁分离得到高纯度、可在体外条件下培养的肝血窦内皮细胞,其次用不同浓度的DAPT(15 μmol/L、45 μmol/L、75 μmol/L)处理细胞,然后通过MTT检测细胞增殖情况、Real time PCR检测相关分子改变.结果:在体外条件下DAPT对肝血窦内皮细胞的增殖起到促进作用,这种促进作用随着DAPT浓度的增加相应的增加;DAPT能够导致肝血窦内皮细胞Notch信号下游分子Hes1表达下调,VEGF信号中VEGFR1表达下调,VEGFR2表达上调.结论:γ分泌酶抑制剂(DAPT)通过抑制肝血窦内皮细胞Notch信号,引起肝血窦内皮细胞表面VEGFR1表达下调,VEGFR2 表达上调显著增加肝血窦内皮细胞的活性.     

Zn[2+]对中华绒螯蟹zao状幼体肝胰腺超微结构的影响

研究了不同Zn[2+]浓度对中华绒螯蟹(Eriocheir sinensis)zao状幼体肝胰腺细胞超微结构的影响。当Z[2+]浓度超过200 μg/L时，与对照组相比，肝胰腺结构受到了显著的影响。成熟和正在形成的B细胞的空泡中有很多含有金属的电子致密颗粒(EDG，可能为金属蛋白复合体)，随着B细胞的成熟和B细胞从肝胰腺管壁上脱落，这些EDG也被释放到管腔中，因此肝胰腺的管腔中常有许多此类颗粒存在。B细胞空泡或管腔中的EDG与环境中Zn[2+]浓度高低呈正相关。E细胞质中也出现了很多空泡，与正常E细胞的结构明显不同。R细胞的细胞质常解体形成大的空泡，被破坏的程度较为严重。在Zn[2+]浓度>1000 μg/L时，肝胰腺遭到严重破坏，细胞结构几乎不存在。研究结果表明，肝胰腺的B细胞在Zn[2+]的解毒方面起重要作用，但当Zn[2+]浓度超过了肝胰腺B细胞的解毒能力时，就会引起肝胰腺细胞(如R和E细胞)结构异常，甚至破坏整个肝胰腺细胞结构，从而影响幼体的生长，甚至造成死亡。     

猞猁肝脏的组织结构观察及EGF在肝脏中的表达

利用切片方法观察了猞猁Felislynx肝脏的组织结构,应用免疫组织化学方法检测了表皮生长因子(EGF)在肝脏中的表达。结果显示,肝脏外被覆一层结缔组织薄膜,肝小叶不规则且分界不清,肝板、肝血窦及狄氏间隙围绕中央静脉呈放射状排列,肝板由一排肝细胞构成。肝细胞呈圆形或多边形,多为单核,少数具双核,肝细胞间比较松散。肝血窦发达,内可见血细胞。EGF阳性反应主要定位于肝细胞质中,表明EGF可能参与细胞新陈代谢过程的调控。     

17β-雌二醇对雄性剑尾鱼生长发育的影响

用组织学的方法研究了50μg/L 17β-雌二醇(E2)持续50d暴露对剑尾鱼精巢、肝脏和鳃组织结构变化的影响,结果显示,剑尾鱼受E2暴露后,精巢内的精小囊数量减少,精原细胞发育停滞,精子数量稀少甚至没有;肝细胞胞质内出现脂肪空泡和脂肪沉积等脂肪肝症状;鳃丝和鳃小片出现不同程度的肿胀、增生、融合现象.结果表明,E2具强雌激素效应.对剑尾鱼精巢、肝脏和鳃组织的损伤具有时间效应,随着暴露时间延长其损伤更严重,但都在其耐受范围之内,未造成鱼体的死亡.精巢组织结构损伤可作为检测水环境雌激素污染生物标记.     

Zn2+对中华绒螯蟹溞状幼体肝胰腺超微结构的影响

研究了不同Zn2+浓度对中华绒螯蟹(Eriocheir sinensis)()状幼体肝胰腺细胞超微结构的影响.当Zn2+浓度超过200 μg/L时,与对照组相比,肝胰腺结构受到了显著的影响.成熟和正在形成的B细胞的空泡中有很多含有金属的电子致密颗粒(EDG,可能为金属蛋白复合体),随着B细胞的成熟和B细胞从肝胰腺管壁上脱落,这些EDG也被释放到管腔中,因此肝胰腺的管腔中常有许多此类颗粒存在.B细胞空泡或管腔中的EDG与环境中Zn 2+浓度高低呈正相关.E细胞质中也出现了很多空泡,与正常E细胞的结构明显不同.R细胞的细胞质常解体形成大的空泡,被破坏的程度较为严重.在Zn2+浓度>1 000 μg /L时,肝胰腺遭到严重破坏,细胞结构几乎不存在.研究结果表明,肝胰腺的B细胞在Zn 2+的解毒方面起重要作用,但当Zn2+浓度超过了肝胰腺B细胞的解毒能力时,就会引起肝胰腺细胞(如R和E细胞)结构异常,甚至破坏整个肝胰腺细胞结构,从而影响幼体的生长,甚至造成死亡.     

亚硒酸钠对烟草冠瘿组织生长的影响及其与内源激素的关系

低浓度(0.1～1μmol/L)亚硒酸钠(Na_2-ScO_s)对烟草冠瘿组织的生长有促进作用;但浓度较高时(5～20μmol/L)不仅对生长有抑制作用,同时能促使其内源吲哚乙酸(IAA)和玉米素(ZA)含量下降,脱落酸(ABA)含量增加,IAA氧化酶活性增强。适宜浓度的外源2,4-D,IAA,6-BA,ZA都可部分缓解较高浓度Na_2SeO_3对生长的抑制作用,其中2,4-D,6-BA的缓解能力分别大于IAA和ZA。Na_2SeO_3还引起烟草冠瘿组织过氧化物同工酶谱发生显著变化,这种变化可被适宜浓度的外源6-BA逆转,并向正常组织方向转化,缓解较高浓度Na_2SeO_3对生长的抑制作用与逆转其过氧化物同工酶谱变化的6-BA浓度范围完全一致。     

两种温度条件下苯酚对铜绿微囊藻大型变种生长的影响

模拟春秋季水温 (2 2℃ )和夏季水温 (3 0℃ )环境 ,用不同浓度的苯酚处理铜绿微囊藻大型变种。结果显示 :正常水体中该藻在 3 0℃比 2 2℃生长快。浓度C≤ 2 0 0 μg/mL的苯酚对它的生长有促进作用 ,而浓度C≥ 40 0 μg/mL的苯酚则抑制其生长 ,高浓度苯酚胁迫下的藻细胞光合速率 ,可溶性蛋白含量下降 ;细胞膜透性增大 ;超氧阴离子 (O 2 )和丙二醛 (MDA)相对含量升高 ;超氧化物歧化酶 (SOD)活性降低 ,藻体自发荧光较对照减弱。表明该藻的生长更适合于夏季高温条件 ,且较高浓度苯酚对其有较强抑制作用。     

Serology and systematics of the Ebenales and the Theales

The systematic position ofthe Ebenaceae, Sapotaceae, Styracaceae, Ochnaceae, Stachyuraceae, Dipterocarpaceae, Clusiaceae and Hypericaceae has been investigated using serological comparisons of sets of antigenic determinants. The results show that the Sytracaceae and Sapotaceae are undoubtedly more closely associated with the Actinidiaeceae and Theaceae, respectively, than with each other. We found no corresponding determinants betnween antigen systems from the Ebenaceae and systems from any other family whose relations to this family have been proposed. As discovered previously, investigations of antigen systems from the Ochnaceae, Dipterocarpaceae, Stachyuraceae, Clusiaceae and Hypericaceae are against the idea of a natural order “Theales” in which these families, or at least some of them, are combined with the Theaceae and Actinidiaceae. This paper completes our previous investigations which largely support a superorder Ericanae sensu Ehrendorfer and Takhtajan. We propose to include the Actinidiaceae and Theaceae in this superorder, assigning them a central position laong with the Sapotaceae and Sytracaeae on one side and the Primulales and Ericales on the other. Another most interesting finding is that there are corresponding determinants between antigen systems from the members of the Ericanae and representatives of the Polemoniaceae and Loasaceae.     

On the structure and dynamics of the complex of the nucleosome and the linker histone

Several different models of the linker histone (LH)–nucleosome complex have been proposed, but none of them has unambiguously revealed the position and binding sites of the LH on the nucleosome. Using Brownian dynamics-based docking together with normal mode analysis of the nucleosome to account for the flexibility of two flanking 10 bp long linker DNAs (L-DNA), we identified binding modes of the H5-LH globular domain (GH5) to the nucleosome. For a wide range of nucleosomal conformations with the L-DNA ends less than 65 Å apart, one dominant binding mode was identified for GH5 and found to be consistent with fluorescence recovery after photobleaching (FRAP) experiments. GH5 binds asymmetrically with respect to the nucleosomal dyad axis, fitting between the nucleosomal DNA and one of the L-DNAs. For greater distances between L-DNA ends, docking of GH5 to the L-DNA that is more restrained and less open becomes favored. These results suggest a selection mechanism by which GH5 preferentially binds one of the L-DNAs and thereby affects DNA dynamics and accessibility and contributes to formation of a particular chromatin fiber structure. The two binding modes identified would, respectively, favor a tight zigzag chromatin structure or a loose solenoid chromatin fiber.     

Biophysics and Structure of the Patch and the Gigaseal

Interpreting channel behavior in patches requires an understanding of patch structure and dynamics, especially in studies of mechanosensitive channels. High resolution optical studies show that patch formation occurs via blebbing that disrupts normal membrane structure and redistributes in situ components including ion channels. There is a 1-2 μm region of the seal below the patch where proteins are excluded and this may consist of extracted lipids that form the gigaseal. Patch domes often have complex geometries with inhomogeneous stresses due to the membrane-glass adhesion energy (E_a), cytoskeletal forces, and possible lipid subdomains. The resting tension in the patch dome ranges from 1-4 mN/m, a significant fraction of the lytic tension of a bilayer (∼10 mN/m). Thus, all patch experiments are conducted under substantial, and uneven, resting tension that may alter the kinetics of many channels. E_a seems dominated by van der Waals attraction overlaid with a normally repulsive Coulombic force. High ionic strength pipette saline increased E_a and, surprisingly, increased cytoskeletal rigidity in cell-attached patches. Low pH pipette saline also increased E_a and reduced the seal selectivity for cations, presumably by neutralizing the membrane surface charge. The seal is a negatively charged, cation selective, space with a resistance of ∼7 gigohm/μm in 100 mM KCl, and the high resistivity of the space may result from the presence of high viscosity glycoproteins. Patches creep up the pipette over time with voltage independent and voltage dependent components. Voltage-independent creep is expected from the capillary attraction of E_a and the flow of fresh lipids from the cell. Voltage-dependent creep seems to arise from electroosmosis in the seal. Neutralization of negative charges on the seal membrane with low pH decreased the creep rate and reversed the direction of creep at positive pipette potentials.     

Epigenetics and aging: the targets and the marks

'Aging epigenetics' is an emerging field that promises exciting revelations in the near future. Here we focus on the functional and biological significance of the epigenetic alterations that accumulate during aging and are important in tumorigenesis. Paradigmatic examples are provided by the global loss of DNA methylation in aging and cancer and by the promoter hypermethylation of genes with a dual role in tumor suppression and progeria, such as the Werner syndrome (WRN) and lamin A/C genes. Another twist is provided by sirtuins, a family of NAD-dependent deacetylases that act on Lys16 of histone H4, which are emerging as a link between cellular transformation and lifespan.     

Metamorphosis in the Cirripedia Rhizocephala and the homology of the kentrogon and trichogon

The Rhizocephala are considered to be monophyletic due to several synapomorphies in the ontogeny of the cndoparasitic phase. The various types of metamorphosis described in the Rhizocephala are discussed and compared to metamorphosis in the Cirripedia Thoracica and Acrothoracica. In males and females of the suborder Kentrogonida. the cyprid settles and metamorphoses into a new instar, in males the trichogen and in females the infective kentrogon. The kentrogon goes through yet another. incomplete moult associated with the development of the stylet. Within the three kentrogonidan families. the Iernaeodiscid-peltogastrid type of kentrogon differs from the sacculinid type in the mode of attachment to the host. in the complexity of internal anatomy. in the position and penetration of the stylet, and in whether or not the cyprid carapace must be shed prior to penetration of the stylet. In the Akentrogonida metamorphosis never results in a new instar. Where observed (Clistosaccidae and Thompsoniidae). both male and female cyprids settle and penetrate into their substrate (female parasite or new host) with one of the antennules. Using the antennule as a syringe. male cyprids inject spermatogonia while female cyprids injects embryonic cells developing into an endoparasite. By comparison with metamorphosis in the Cirripedia Thoracica and Acrothoracica it is concluded that the presence of a metamorphic moult leading to a post-cyprid instar is plesiomorphic and that the trichogon and kentrogon are homologous with the first metamorphosed juvenile in these outgroups. The abbreviated ontogeny in the Akentrogonida without metamorphic moult and post-cyprid larval instars is considered apomorphic. This contradicts the long-held supposition that the Akentrogonida are the most‘primitive’Rhizocephala and dovetails with new information that this suborder contains many advanced traits. Within the Kentrogonida. the lernacodiseid-peltogastrid type of kentrogon is considered more plesiomorphic than the sacculinid type, which resembles the clistosaccidthompsoniid type in having the antennules involved in the penetration process. The homologization of the kentrogon with a juvenile barnacle indicates that presence of a kentrogon is plesiomorphic within the Rhizocephala and that the Kentrogonida is paraphyletic.     

Phymosomatoid echinoids from the campanian and the maastrichtian of Belgium and the Netherlands

Phymosomatoid echinoids from the Campanian and the Maastrichtian of Belgium and the Netherlands are systematically revised. Ten species, belonging to four genera are identified and described. One new species is introduced:Gauthieria?mosae sp. nov.     

Baculoviruses and apoptosis: the good, the bad, and the ugly

Since 1991, when a baculovirus was first shown to inhibit apoptosis of its host insect cells, considerable contributions to our knowledge of apoptosis have arisen from the study of these viruses and the anti-apoptotic genes they encode. Baculovirus anti-apoptotic genes include p35, which encodes the most broadly acting caspase inhibitor protein known, and iap (inhibitor of apoptosis) genes, which were the first members of an evolutionarily conserved gene family involved in regulation of apoptosis and cytokinesis in organisms ranging from yeast to humans. Baculoviruses also provide an ideal system to study the effects of an apoptotic response on viral pathogenesis in an animal host. In this review, I discuss a number of interesting recent developments in the areas of apoptotic regulation by baculoviruses and the effects of apoptosis on baculovirus replication and pathogenesis.