Observation on the urinogenital papilla and sexual dimorphism in some Indian gobiids (Gobiidae: Teleostei)

A thorough comparative study on the urinogenital papilla and sexual dimorphism has been made for the first time in both the sexes of twelve Indian gobiids: Glassogobius giuris (Hamilton); Acentrogobius cyanomos (Bleeker); Eleotriodes muralis (Valenciennes); Parapocryptes serperaster (Richardson); Apocryptes bato (Hamilton); Scartclaos viridis (Hamilton); Boleophthalmus boddarti (Pallas), Periophthalmus schlosseri (Pallas); P. koelreuteri (Pallas); Taenioides anguillaris (Linnaeus); T. buchanani (Day); Odontamblyopus rubicundus (Hamilton). The urinogenital papilla, originating as a free muscular organ from the ventral surface of the body-wall and shortly behind anus, is present in both the sexes. It is an important organ of primary sex recognition in all species. In case of male the papilla is conical, broad at the base and in female it is either flattened, distally truncated or bluntly rounded. The presence of permanent colour mark over the specific region of the body surface is another secondary sexual character in a few species. Besides, colouration may also be a nuptial secondary sex character developed in some during peak breeding season. The enlargement and colouration of the organ is subject to seasonal variations parallel to the seasonal gonadal cycle. The histological architecture of the papilla shows a high degree of cellular specialization and an interrelationship to the urinary and genital ducts. The functional efficacy and significance of the papilla in the breeding biology of these fishes has been discussed.

Mortality estimates of Indian ribbon fish Trichiurus lepturus off Maharashtra coast

In view of its new found status in export market, ribbon fish resources need to be continually monitored. Mortality, one of the important parameter is reported for the Indian ribbon fish Trichiurus lepturus Linnaeus in the present communication. The average annual instantaneous rate of total (Z), natural (M) and fishing mortality coefficient (F) were estimated as 2.66, 0.77 and 1.89 respectively for the 1995 to 1997 period. The exploitation rate (U) and exploitation ratio (E) were estimated as 0.66 and 0.71 respectively, which is beyond the optimum thrust reduction in the fishing effort for this stock along the Maharashtra coast is necessary.

Exploitation of tunas in Ceylon's coastal waters

Ceylon’s fishery for the tunas is presently limited to the coastal waters which in the present context have an off-shore limit of 15 miles and our contribution to the world tuna production is a little over 1%. Four varieties of tuna are largely exploited in the coastal waters. Of these, Baleya or the skipjack (Katsuwonus pelamis Linn. 1758) is the predominant variety followed by attavalla or mackerel tuna (Euthynnus ajfinis, Cantor, 1850), kelawalla or yellowfin (Thunnus albacares, Bonnaterre, 1788) and alagoduwa or frigate mackerel (Auxis thazard Lacepede, 1802). Other varieties like the thora-baleya or bonito (Sarda orientalis) and asgedi kelawalla or big eye tuna (Thunnus obesus) are also landed frequently but in extremely small quantities. Figure 1 illustrates the relative composition of the tuna varieties in the catch and their percentage composition further sub-divided according to the type of effort applied. It is evident that Ceylon's coastal fishery for tunas is greatly influenced by the production of smaller varieties of the tunas.

Distribution and length-weight relationship of tunas and tuna-like fishes around Ceylon

Tunas and tuna-like fishes have contributed considerably towards the increase in fish production from Ceylon's coastal waters, during the last five years and in this blood fish group lies a potential resource for a further increase in production. Consequently considerable attention is being paid to the study of these species. Length frequency sampling of these species are being carried out and quite often it becomes necessary to convert catch in terms of weight to catch in terms of number, when estimating apparent abundance of the stock. The length-weight relationship in addition to its usefulness in converting length frequency data to weight frequency data for such purpose is of general value to biologists and even to fishermen. The six species studied are yellowfin tuna (Thunnus alacares, Bonneterre), skipjack tuna (Katsuwonus pelamis, Linnaeus), mackerel tuna (Buthynnus affinis, Cantor), frigate mackerel (narrow corseleted Auxis thazard, Lacepede and broad corseleted A. rochie, Risso) and bonito (Saida orientalis, T&S).

Three-dimensional SBLI control for transonic airfoils

The application of shock control to transonic airfoils and wings has been demonstrated widely to have the potential to reduce wave drag. Most of the suggested control devices are two-dimensional, that is they are of uniform geometry in spanwise direction. Examples of such techniques include contour bumps and passive control. Recently it has been observed that a spanwise array of discrete three-dimensional controls can have similar benefits but also offer advantages in terms of installation complexity and drag. This paper describes research carried out in Cambridge into various three-dimensional devices, such as slots, grooves and bumps. In all cases the control device is applied to the interaction of a normal shock wave (M=1.3) with a turbulent boundary layer. Theoretical considerations are proposed to determine how such fundamental experiments can provide estimates of control performance on a transonic wing. The potential of each class of three-dimensional device for wave drag reduction on airfoils is discussed and surface bumps in particular are identified as offering potential drag savings for typical transonic wing applications under cruise conditions.

A re-description of the little known rabbit fish Siganus lineatus (Cuvier and Valenciennes) (Pisces:Siganide) with notes on siganid fishes of the Vembanad Lake

Siganus lineatus (Cuv. and Val) is reported from the coast of peninsular India for the first time and a detailed description of it is given based on morphology and meristic characters. It differs from the other allied species of the genus Siganus Forskal in having an oval body without spots and having fifteen parallel longitudinal golden yellow bands, relatively larger last dorsal spine, maxillary position far below the level of the orbit and cheek with distinct rows of scales. S. javus (Linnaeus) and S. canaliculatus (Park) were also obtained from the Vembanad Lake. Short notes on the habitat, occurrence, abundance, seasonal and geographic distribution in relation to fluctuating hydrological conditions of the Vembanad Lake are incorporated together with a key for their identification.

一种预防或治疗艾滋病的药物及其制备方法和应用

提供一种药用有效成分酒花查尔酮(xanthahumol)用于预防和治疗艾滋病。具体地，利用植物啤酒花(Humulus lupulus)为原料，通过酒精提取和溶剂处理，硅胶柱层析以氯仿/乙酸乙酯混合溶剂洗脱，结晶得到酒花查尔酮(xanthahumol)纯品。实验证明该化合物具有显著的体外抗HIV-1活性，可用于制备预防和治疗艾滋病的药物。

补充营养对柑橘凤蝶卵成熟和雄虫寿命的影响

在实验室条件下,定量地研究了蔗糖、葡萄糖、果糖和蜂蜜等4种补充营养物对柑橘凤蝶卵成熟和雄虫寿命的影响.结果表明:(1)补充蔗糖、果糖和蜂蜜水的雌虫孕成熟卵量都显著高于清水对照组,其中补充蔗糖的雌虫孕成熟卵量最高;(2)不同的补充营养物对雌虫孕亚成熟卵量和未成熟卵量的影响不显著;(3)饲喂蔗糖、果糖和蜂蜜的雄虫寿命显著高于对照组,其中饲喂果糖的雄虫寿命最长;(4)饲喂添加不同浓度NaCl溶液的蜂蜜水的雄虫寿命比仅饲喂蜂蜜水的雄虫短,当NaCl溶液浓度为0.001 mol/L,0.1 mol/L和 1 mol/L 时,雄虫寿命显著低于对照,其中饲喂0.001 mol/L NaCl溶液的雄虫寿命最短.

柑橘凤蝶生殖系统解剖学研究

通过解剖柑橘凤蝶成虫的生殖系统，研究了柑橘凤蝶生殖器官的形态及结构特点。

On the fishes and fisheries of Lake Baringo

Six fish species are known to occur in Lake Baringo. Tilapia nilotica Linnaeus 1757, Barbus gregorii Boulenger 1902, Clarias mossambicus Peters 1852 and Labeo cylindricus Peters 1852 were recorded in 1930-31. In 1969, two more fish species were identified: Aplocheilichthys sp. and Barbus lineomaculatus Boulenger 1903. T. nilotica is the only fish species commercially exploited. But the catches, catch per unit effort and the mean size of fish caught in commercial gillnets have declined since 1968. B. gregorii is important in the subsistence rod-and-line fishery. L. cylindricus, C. mossambicus, B. lineomaculatus and Aplochelichthys sp. are not commercially exploited.

东湖沉积物中微生物磷脂的垂向分布

以武汉东湖柱状沉积物为研究对象,利用磷脂法测定了3个采样点各层的微生物量,同时测定了沉积物中各层的pH,简要分析了沉积物中磷脂含量的垂向分布与pH垂向分布的相关性。结果表明:各样点沉积物中磷脂平均含量分别为:1号点59.40nmol/g.dw,2号点为20.56nmol/g.dw,3号点为31.57nmol/g.dw。在沉积物的垂向分布上,微生物量与pH均随着沉积物深度的增加而降低,并且存在很高的相关系数。

栉江珧同工酶多态性的分析

采用垂直板聚丙烯酰胺梯度凝胶电泳对栉江珧(Atrina pectinata Linnaeus)消化盲囊进行了5 种酶(SOD、EST、MDH、ME、LDH) 的同工酶分析。结果表明不同个体的同工酶表达呈现多态现象,个体间酶带带型既有相一致的共同特征谱带,又有较多的变异,5种酶均可把样品大致区分为差异明显的2 种或3 种类型,而且酶谱类型与形态类型基本对应,同工酶表达上的多样性表明栉江珧种内在生化遗传上存在较大的变异, 具有较丰富的遗传多态性。

Le斑马鱼nanos1基因在配子发生中的原位杂交研究

利用组织原位杂交技术,以地高辛标记的反义RNA为探针,检测了斑马鱼(Daniorerio)nanos1基因在卵子发生及精子发生中的表达分布特点,初步探讨了该基因在斑马鱼配子发生中可能的功能。结果表明:在斑马鱼卵子发生中,nanos1mRNA均匀分布于卵原细胞和各时期卵母细胞的胞质中;在卵原细胞和Ⅰ、Ⅱ期卵母细胞中,nanos1mRNA的杂交信号十分强烈,而较晚期卵母细胞中信号明显减弱。在斑马鱼精子发生中,nanos1mRNA可在精原细胞和初级精母细胞中检测到。nanos1mRNA的阳性信号在精原细胞中极为