用冷热休克诱导三倍体近江牡蛎

在近江牡蛎(Ostrea rivularis Gould)卵子授精后25分钟,分别用高温(35℃)和低温(10℃)持续处理20分钟,其胚胎发育初期的三倍体诱导率分别达到64％和69％。在这个高温点和低温点以外随着处理温度的升高或降低,三倍体诱导率均迅速减小。     

用冷热休克诱导四倍体近江牡蛎

当近江牡蛎授精卵发育至第一次卵裂前3min或个别受精卵开始出现第一次卵裂时,分别用热体克(37℃,39℃,41℃)和冷休克(8℃,10℃,12℃)处理3min诱导四倍体。测定39℃热休克组胚胎早期的四倍体诱导率为28％,10℃冷休克组胚胎早期的四倍体诱导率为30%。温度过高(如42℃以上)可导致卵的高死亡率。     

生长激素与胰岛素样生长因子-Ⅰ对马氏珠母贝壳生长形成相关基因表达的影响

研究了外源生长激素与胰岛素样生长因子-Ⅰ处理对马氏珠母贝Pinctada fucata Gould胰岛素相关多肽受体基因(irr)和5种壳基质蛋白基因(nacrein、efcbp、n19、aspein及accbp)表达水平的影响。结果表明,激素处理显著提高了irr基因的表达水平(P<0.05),这与其在软体动物中作为胰岛素样生长因子受体的作用相一致。nacrein基因的表达水平在激素处理组也有显著升高(P<0.05),表明生长激素与胰岛素样生长因子-Ⅰ两种外源激素都增强了马氏珠母贝的生长代谢水平;与对照组相比,n19、aspein与accbp3个基因的表达水平在激素处理组均下调(P<0.05),说明这3个基因的表达受到激素调节通路的抑制作用。此外,研究发现aspein与accbp两个基因的表达在各个实验样本中具有极高的相关性,说明这两个基因在激素通路中可能受到同一个上游因子调控。efcbp基因表达水平在激素处理组与对照组之间表达稳定,各样本之间无显著性的变化(P>0.05)。     

斗嫁蜮精子发生及雄性性腺组织学研究

采用石蜡切片法,对分布于粤西沿海的斗嫁蜮Cellana grata(Gould)的精子发生和雄性性腺的组织结构进行了研究。斗嫁蜮精子发生经历雄性性细胞的增殖、生长、成熟、变态等阶段.依据精子发生过程中生精细胞形态的变化,精子发生过程可分为精原细胞期、初级精母细胞期、次级精母细胞期、精细胞期和精子形成期等5期。雄性性腺组织主要由滤泡构成,滤泡为生殖细胞增殖、生长、成熟、变态的场所,滤泡腔中的精子经生殖输送管向外输送。显微观察与分析表明:(1)精子发生中,生长期不明显,初级精母细胞较精原细胞小;(2)生精细胞及核的大小随发育逐渐变小,核嗜碱性逐渐增强;(3)精子发生过程中的变态期长,易观察到变态过程中的不同形态的精细胞;(4)成熟精子为鞭毛型,头部短杆状,约0.5×(3~4)μm,尾部细长呈鞭毛状;(5)生长-成熟期的雄性性腺由形态较规则的(多边形)滤泡构成,滤泡界限清晰;(6)雄性滤泡壁由不同发育时期的生精细胞依次排列,较原始的生精细胞呈嗜酸性,靠近滤泡膜分布,而发育晚期的生精细胞呈嗜碱性,渐离滤泡膜分布,成熟精子群集并呈涡旋状分布于腔中;(7)成熟雄性性腺可伸入足部或肝组织中;在肝组织切片中,可观察到结构不同的4个级别的生殖输送管;8)斗嫁蜮雌雄异体,但存在雌雄同体、性转化现象。还对斗嫁蜮精子发生与成熟过程及雌雄同体的有关问题进行了探讨。     

近江牡蛎肠道细菌及其产酶能力

从近江牡蛎肠道中分离出21株菌,其中, 9株为革兰阳性菌, 12株革兰阴性菌。为寻找能分泌多种酶的有益微生物,研究了它们蛋白酶、脂肪酶、淀粉酶、纤维素酶的产酶能力。结果表明,有61 .9%的菌株能分泌蛋白酶或淀粉酶(各有13株菌);有52. 4%的菌株能分泌脂肪酶(11株菌);有33. 3%的菌株能产纤维素酶(7株菌)。在这21株菌中,产4种酶的有5株菌,产3种酶的3株菌,产两种酶的5株菌,产1种酶的3株菌,不产酶的仅有5株菌。不产酶的菌株仅占细菌总数的23. 8%,而各种产酶菌则高达76. 2%,由此表明细菌在近江牡蛎对食饵消化过程的重要性。     

Determination of the rotation curve for stars of the Gould Belt using bottlinger's formulas

Based on the Hipparcos catalog and the radial velocities of stars published to date, we perform a kinematic analysis of OB stars. Parameters of the general Galactic rotation were determined from distant OB stars. We used the residual velocities of stars corrected for the general Galactic rotation to study the proper rotation of nearby OB stars. Geometrical characteristics of the Gould Belt were estimated by analyzing its kinematic parameters. We obtained parameters of peculiar solar motion as well as parameters of the proper rotation, expansion, and contraction for rotation around both the Galactic z axis and an axis perpendicular to the plane of symmetry of the disk. Kinematic parameters of the proper differential rotation were found for two age groups of nearby OB stars. Almost all of the nearby OB stars were shown to rotate in the same direction as the Galactic rotation. We constructed rotation curves.     

Kinematics of the Scorpius-Centaurus OB association

A fine structure related to the kinematic peculiarities of three components of the Scorpius-Centaurus association (LCC, UCL, and US) has been revealed in the UV-velocity distribution of Gould Belt stars. We have been able to identify the most likely members of these groups by applying the method of analyzing the two-dimensional probability density function of stellar UV velocities that we developed. A kinematic analysis of the identified structural components has shown that, in general, the center-of-mass motion of the LCC, UCL, and US groups follows the motion characteristic of the Gould Belt, notably its expansion. The entire Scorpius-Centaurus complex is shown to possess a proper expansion with an angular velocity parameter of 46 ± 8 km s^?1 kpc^?1 for the kinematic center with l ₀ = ?40° and R ₀ = 110 pc found. Based on this velocity, we have estimated the characteristic expansion time of the complex to be 21 ± 4 Myr. The proper rotation velocity of the Scorpius-Centaurus complex is lower in magnitude, is determined less reliably, and depends markedly on the data quality.     

Radio-Loud and Radio-Quiet Gamma-Ray Pulsars from the Galaxy and the Gould Belt

We present results of a population synthesis study of radio-loud and radio-quiet γ-ray pulsars from the Galactic plane and the Gould Belt. The simulation includes the Parkes multibeam pulsar survey, realistic beam geometries for radio and γ-ray emission from neutron stars and the new electron density model of Cordes and Lazio. Normalizing to the number of radio pulsars observed by a set of nine radio surveys, the simulation suggests a neutron star birth rate of 1.4 neutron stars per century in the Galactic plane. In addition, the simulation predicts 19 radio-loud and 7 radio-quiet γ-ray pulsars from the plane that EGRET should have observed as point sources. Assuming that during the last 5 Myr the Gould Belt produced 100 neutron stars, only 10 of these would be observed as radio pulsars with three radio-loud and four radio-quiet γ-ray pulsars observed by EGRET. These results are in general agreement with the recent number of about 25 EGRET error boxes that contain Parkes radio pulsars. Since the Gould Belt pulsars are relatively close by, the selection of EGRET radio-quiet γ-ray pulsars strongly favors large impact angles, β, in the viewing geometry where the off-beam emission from curvature radiation provides the γ-ray flux. Therefore, the simulated EGRET radio-quiet γ-ray pulsars, being young and nearby, most closely reflect the current shape of the Gould Belt suggesting that such sources may significantly contribute to the EGRET unidentified γ-ray sources correlated with the Gould Belt.     

尖刀蛏的生殖周期

本文是尖刀蛏Ｃｕｌｔｅｌｌｕｍ ｓｃａｌｐｒｕｍ（Ｇｏｕｌｄ）生物学系列研究之一，报告了１９８５年２月至１９８６年２月福宁湾尖刀蛏生殖腺周年发育和组织学观察的初步结果。性腺发育分４期：增殖期、成熟期、排放期、耗尽期。存在着雌雄同体和性变现象。雌雄性比和性变与贝龄有一定关系。