眼柄粗提物对凡纳滨对虾性分化的影响

采用生化方法制备凡纳滨对虾[Litopenaeus(Penaeus)vannamei)]眼柄粗提物,用活体注射法研究不同粗提物剂量对去眼柄凡纳滨对虾卵母细胞直径大小的影响,以检验其性腺抑制素(Gonadinhibiting hormone,GIH)的生物活性;在凡纳滨对虾仔虾后17、22和27 d,分别以不同浓度眼柄粗提物浸泡24 h,结果显示:除0.001个眼柄/mL的GIH浓度外,0.01、0.1和1个眼柄/mL组均显著降低凡纳滨对虾卵母细胞直径(P﹤0.05);浸泡处理后,仔虾后17 d GIH处理组凡纳滨对虾雌性率达70.1%～80.1%;仔虾后22 d GIH处理组雌性率达65.8%～71.7%,各浓度GIH处理组雌性率比对照组(雌雄比例约为1:1)显著提高(P﹤0.05);仔虾后27 d,0.01和1个眼柄/mL处理组雌性率(约58%)略高于对照组,但0.1个眼柄/mL处理组雌性率(73.1%)与对照组相比显著提高(P﹤0.05)。结果表明较低浓度的眼柄粗提物可明显诱导凡纳滨对虾雌性化,在仔虾后22 d前处理效果最佳。     

Identification of phase and sex-related ISSR markers of red algaGracilaria lemaneiformis

Six ISSR primers are employed to display the polymorphism of different phases and sexes of red alga Gracilaria lemaneiformis, and two of them, P1 and P3, amplified distinct band patterns. The ISSR pattern amplified by primer P1 of the female gametophyte is identical to that of tetrasporophyte, but distinct from that of male gametophyte. Of the bands produced by primer P3, one is specific to female gametophyte. Three morphologically similar fronds can be easily identified using ISSR technique. Two specific markers, SM1 and SF3, related to male gametophyte and female gametophyte, are cloned and sequenced. The homologous sequences of SM1 are found to encode a hypothetical protein. There is no homologous sequence of SF3 that can be found in GenBank.     

Spatial Aspects of Restrictions on Registered Sex Offenders

Restrictions in the USA on registered sex offenders (RSOs) are examined from the spatial aspects. The long history of various restrictions imposed by government, particularly local ones, is covered in the introduction. Spatial aspects, such as delineation of zones from which certain activities or certain people are excluded is the focus. Then the nature of restrictions on RSOs is considered at the state, county and municipal level. Typical of restrictions are that RSOs are prohibited from moving into residence within a prescribed distance of certain features in a community. The distances are typically 1,000 feet but are quite variable. Typical proscribed venues are schools, parks and day care centers, but there can be many others such as bus stops. Spatial aspects of these restrictions, such as how offender locations are geocoded and represented and how proscribed venues are delineated is analyzed. Specific details and theoretical concerns related to the many problematic issues with RSO restrictions is presented. In particular questions of their constitutionality and efficacy are raised. The paper concludes with a discussion of the implications of RSO restrictions for the discipline of geography in general and for the evolution of increasingly precise methods of spatial analysis in particular.     

日本刺沙蚕的性信息素研究

日本刺沙蚕（Ｎｅｒｅｉｓｊａｐｏｎｉｃａ）广泛分布于中国沿海，是鱼、虾的优良饵料，冬末春初繁殖时离开河口向盐度较高的海区移动。与多齿围沙蚕，褐片阔沙蚕等其它沙蚕不同，日本刺沙蚕在繁殖过程中不出现完全变态，但是与其它沙蚕一样，其繁殖过程也受一组性信息素控制。从雌性成熟的日本刺沙蚕体腔液中提取并鉴定出一种有生物活性的挥发性物质──辛二烯－［３，５］－酮－［２］，这种化合物可以增加群浮个体在配子释放之前婚舞时的游动速度．但不诱导配子释放。在许多沙蚕中有着性信息素作用的５－甲基－３－庚酮，在日本刺沙蚕体腔液中没有发现，也没有性信息素作用。     

Complementary (secondary) metabolites in a soft coral: sex-specific variability, inter-clonal variability, and competition

Sex‐specific interactions involving competition for space between the dioecious alcyonacean soft coral Sarcophyton glaucum and the scleractinian coral Acropora robusta were assessed experimentally on Bald Rock, central region of the Great Barrier Reef. To examine this, plus inter‐clonal responses, one male colony of S. glaucum, known to produce sarcophytoxide as its predominant complementary (secondary) metabolite, was sectioned, producing 10 clones. The same was done for a female colony. These two sets of clones were then relocated to grids and placed in contact with Acropora clones. Relocated and non‐relocated controls were also monitored. High levels of tissue necrosis were observed in the hard coral under contact conditions with both the male and female clones after 20 days. The development of a protective polysaccharide layer in the alcyonacean was also observed. Differences observed in the concentrations of complementary metabolites within the two different S. glaucum colonies were related to sex. Both under competition and non‐competition conditions, females exhibited significantly higher concentrations of sarcophytoxide than males, and this increased with time. Fatty ester concentration was also higher in females than males, varying significantly through time, and falling dramatically just after spawning. Fatty ester concentrations decreased linearly through time in the male clones. When involved in competition for space, females possessed higher concentrations of fatty esters than males, both at the site of contact and in non‐contact sites, again, decreasing after spawning. No significant changes in sarcophytoxide levels were noted in the parental colonies, but such changes were observed in fatty esters, with the female producing higher concentrations until after spawning. The use of these two variates in the form of a ratio (sarcophytoxide concentration:fatty ester concentration) yielded a variable Rho (ρ) which was a more sensitive indicator of biochemical change than either of its components alone. These two sets of compounds appeared to have a negative association through time and varied highly significantly between sexes. The diterpene sarcophytoxide may be considered an allelopathic or stress metabolite, while the lipids act as energy storage metabolites.     

Chrysophyte reproduction and resting cysts: A paleolimnologist's primer

Chrysophyte algae produce siliceous resting cysts (stomatocysts) that are becoming an increasingly useful class of paleoecological indicator microfossils. This paper provides a review of the role that stomatocysts play in the life cycle and reproductive ecology of freshwater planktonic chrysophytes. Such information provides paleolimnologists with greater insight into the ecology of the vegetative, planktonic growth phase of species contributing stomatocysts to lacustrine microfossil assemblages. Specific chrysophyte reproductive characteristics discussed include: temporal dynamics of vegetative growth and encystment, cyst induction, cyst survivorship, germination requirements and recruitment strategies. This information serves as an introduction to a special issue of the Journal of Paleolimnology which is dedicated to the Application of Chrysophyte Stomatocysts in Paleolimnology.This is the first in a series of four papers published in this dedicated issue entitled Application of Chrysophyte Stomatocysts in Paleolimnology. Dr. C. D. Sandgren served as guest editor for these papers.     

虾夷扇贝不同性别类型2 个Dmrt基因DM 结构域分析

为探讨虾夷扇贝(Patinopecten yessoensis)性别决定和雌雄同体形成的分子机制,利用兼并引物,以闭壳肌基因组DNA为实验材料,扩增和克隆了虾夷扇贝Dmrt基因的DM结构域,雌性、雄性和雌雄同体3种性别共获得2个具有不同DM序列的克隆,序列长度均为141bp,分别命名为Py Dmrt3和Py Dmrt4。Py Dmrt3在3种性别类型中均有克隆,而雄性中还克隆出Py Dmrt4。结果表明,在虾夷扇贝不同性别中,Dmrt基因家族的成员可能会有不同;雄性py Dmrt3的DM结构域核苷酸和氨基酸变异频率高,其次是雌雄同体,雌性的较保守,与其他软体动物DM结构域比对,该基因家族在进化上仍然高度保守,由此推测,部分雄性可能是发生了性逆转的雌雄同体,这种较高的变异性可能也是雌雄同体的一个特点,Py Dmrt4可能参与调控雄性性别的形成。     

长牡蛎两个Dmrt家族基因的时空表达

本文以长牡蛎27个幼虫发育阶段个体以及成体的5个组织织作为实验材料,采用实时荧光定量PCR技术对Dmrt家族中的2个基因（CgDsx和CgDmrtA2）的主要对长牡蛎Dmrt家族中的2个基因（CgDsx和CgDmrtA2）在幼虫时期和成体组织中的表达模式以及在性别决定中可能发挥的作用进行了研究。采用实时荧光定量PCR技术对幼虫27个发育阶段以及成体5个组织的表达进行了测定。结果表明,长牡蛎CgDsx基因在胚胎发育初期有大量表达,其中囊胚期到担轮幼虫初期表达量最高从囊胚期到担轮幼虫初期表达量最高,其后之后表达量开始降低,在D形幼虫后期之后一直维持在极低的表达水平,此后仅在成体的雄性性腺中具有高度表达。该结果表明由此可见,CgDsx 可能也对早期胚胎发育起一定调控作用,除了同时参与了性别决定外,可能也对早期胚胎发育起一定调控作用。CgDmrtA2在长牡蛎所有组织中均有表达,各组织间表达差异不显著,在长牡蛎D形幼虫至壳顶后期表达量较高,表明其参与了胚胎中后期的发育过程说明它参与了胚胎中后期的发育过程,可能与神经的形成相关,但是其具体功能还需要进一步研究。