Age and growth of the blue shark (Prionace glauca) in the North Atlantic Ocean

Age and growth estimates for the blue shark (Prionace glauca) were derived from 411 vertebral centra and 43 tag-recaptured blue sharks collected in the North Atlantic, ranging in length from 49 to 312 cm fork length (FL). The vertebrae of two oxytetracycline-injected recaptured blue sharks support an annual spring deposition of growth bands in the vertebrae in sharks up to 192 cm FL. Males and females were aged to 16 and 15 years, respectively, and full maturity is attained by 5 years of age in both sexes. Both sexes grew similarly to age seven, when growth rates decreased in males and remained constant in females. Growth rates from tag-recaptured individuals agreed with those derived from vertebral annuli for smaller sharks but appeared overestimated for larger sharks. Von Bertalanffy growth parameters derived from vertebral length-at-age data are L∞ = 282 cm FL, K = 0.18, and t0 = –1.35 for males, and L∞ = 310 cm FL, K = 0.13, and t0 = −1.77 for females. The species grows faster and has a shorter life span than previously reported for these waters.

Reproductive biology of the blue swimmer crab (Portunus pelagicus, Decapoda: Portunidae) in five bodies of water on the west coast of Australia

Portunus pelagicus was collected at regular intervals from two marine embayments and two estuaries on the lower west coast of Australia and from a large embayment located approximately 800 km farther north. The samples were used to obtain data on the reproductive biology of this species in three very different environments. Unlike females, the males show a loosening of the attachment of the abdominal flap to the cephalothorax at a prepubertal rather than a pubertal molt. Males become gonadally mature (spermatophores and seminal fluid present in the medial region of the vas deferentia) at a very similar carapace width (CW) to that at which they achieve morphometric maturity, as reflected by a change in the relative size of the largest cheliped. Logistic curves, derived from the prevalence of mature male P. pelagicus, generally had wider confidence limits with morphometric than with gonadal data. This presumably reflects the fact that the morphometric (allometric) method of classifying a male P. pelagicus as mature employs probabilities and is thus indirect, whereas gonadal structure allows a mature male to be readily identified. However, the very close correspondence between the CW50’s derived for P. pelagicus by the two methods implies that either method can be used for management purposes. Portunus pelagicus attained maturity at a significantly greater size in the large embayment than in the four more southern bodies of water, where water temperatures were lower and the densities of crabs and fishing pressure were greater. As a result of the emigration of mature female P. pelagicus from estuaries, the CW50’s derived by using the prevalence of mature females in estuaries represent overestimates for those populations as a whole. Estimates of the number of egg batches produced in a spawning season ranged from one in small crabs to three in large crabs. These data, together with the batch fecundities of different size crabs, indicate that the estimated number of eggs produced by P. pelagicus during the spawning season ranges from about 78,000 in small crabs (CW=80 mm) to about 1,000,000 in large crabs (CW=180 mm).

Monthly spatial occurrence of phytoplankton and zooplankton in River Ogun, Abeokuta, Ogun State, southwest Nigeria

The aim of this study was to investigate the monthly spatial occurrence of phytoplankton and zooplankton in River Ogun, Abeokuta, Southwest Nigeria. This was carried out for seven months between December, 2011 and June, 2012 in 4 stations. A total of 41 species of phytoplankton and 16 zooplankton species from 5 classes respectively were recorded. Zooplankton was dominated by Cladocera throughout the study period while phytoplankton was dominated by blue green algae (Cyanophyta or Cyanobacteria). The dominance of Cyanophyta in this river is similar to findings by Sekadende and co-workers, Ogato, Deng and co-worker, and Shakila and co-worker. The dominance of Cladocera in this river is similar to findings by Ude and co-workers, and Ogbuagu and co-worker.

野生稻OrbHLH2基因的克隆及功能分析

　　bHLH（basic/helix-loop-helix）型的蛋白作为转录因子中的一个家族，控制一系列的生物学过程，例如细胞分化、细胞命运决定等。该家族的共同特点是具有一个bHLH型保守结构域，大约由60个氨基酸组成，在功能上划分为给两个部分：N端的碱性区域和C端的HLH区域，前者具有结合DNA的功能，后者参与了蛋白的二聚化，主要由疏水氨基酸组成。水稻中大多数的bHLH转录因子其功能还不清楚。 　　本论文利用同源克隆的方法，从水稻中得到与拟南芥ICE1同源性最高的基因，并命名为OsbHLH2，然后我们从野生稻中克隆到相关基因OrbHLH2。OrbHLH2 的cDNA全长为1961 bp，编码525个氨基酸。OrbHLH2与拟南芥、荠菜、毛果杨中推测的类ICE1蛋白之间的同源性分别达到46.1%、 45%、 41.2%，推测OrbHLH2可能是一个类ICE1蛋白。亚细胞定位实验结果表明，OrbHLH2定位于细胞核中；酵母自激活实验表明OrbHLH2具有自激活活性，因此推断OrbHLH2可能是一个转录因子。在水稻中对其组织表达模式进行分析发现，OsbHLH2在幼根、老根、幼茎、老茎、幼叶、老叶等组织中表达量极低，而在穗部的表达量很高，这暗示了OrbHLH2可能在水稻发育的特定阶段起重要作用；分析OsbHLH2对各种胁迫的响应，发现该基因在水稻中的表达不受低温、高盐、ABA等胁迫的诱导。 　　将OrbHLH2在拟南芥中异源超表达，转基因材料在发育上没有发现明显的表型改变。分析转基因拟南芥对不同胁迫的耐受性，结果表明：转基因拟南芥对高盐、渗透胁迫的抗性明显增强；分析一些抗逆标记基因的表达水平，发现与转基因拟南芥在高盐条件下DREB1A/CBF3、RD29A、COR15A和KIN1的表达量有不同程度的上调，暗示了在胁迫条件下OrbHLH2可能通过对DREB1A/CBF3途径中的基因的激活，来启动植物对逆境胁迫的响应，从而提高植物的抗逆性。该结果对于提高农作物的抗逆性具有潜在的应用价值。

光敏核不育水稻41 kDa和61 kDa蛋白质的发现、N-端序列分析及其雄性不育性状关系的探讨

光敏核不育水稻农垦58S是石明松于1973年在晚粳农垦58的大田中发现的雄性不育突变体，它在长日照下雄性不育可被用于与恢复系杂交生产杂种，而在短日照下雄性可育能用于自交繁殖，它的恢复系来源广泛。基于这些特性，育种学家用光敏核不育水稻建立的二系杂交水稻制种技术有很大的应用潜力。近十几年来，育种学家用农垦58S作基因供体转育了许多新的不育系，研究结果表明育成的粳型不育系均为光敏不育系，但在育成的籼型不育系中，绝大多数丧失光敏核不育特性，变成温敏不育系。目前因不知光敏核不育的分子遗传机制，尚不能解释这些问题。 本文用双向电泳技术分析了农垦58S和农垦58苗期和育性转换光敏感期叶绿体蛋白质的差异，在农垦58S中发现三个蛋白质(Pl，P2和P3)，其中Pl和P2在苗期和光敏感期叶片内均存在，P3仅在光敏感期的叶片中存在，它们不受长日照或短日照处理的影响。农垦58没有这三个蛋白质。 用制备型双向电泳纯化后，得到SDS - PAGE和IEF纯的Pl和P2。经SDS-PAGE和IEF测定，Pl的等电点是6.2，分子量是41 kDa;P2的等电点是5.8，分子量是61 kDa。现称Pl为P41，P2为P61。氨基酸序列分析和同源性检索发现P41与水稻叶绿体ATP合成酶p亚基和酵母转录因子CAD1有同源性，此外，P41的N-端序列中有一个与蛋白激酶催化核心中的多功能motif Y-G-X-G-X- (P/T)-G-V相似的序列;P61的14个氨基酸长的N-端序列与水稻叶绿体ATP合成酶β亚基的一致。P41和P61 N-端前12个氨基酸的序列也完全一致。 PCR扩增和Southern杂交分析没有发现农垦58S和农垦58之间ATP合成酶β亚基基因(atpB)的多态性。Nothern杂交分析表明农垦58S中仅有一种、与农垦58 atpB mRNA分子量相同的atpB转录产物，但它的atpB mRNA丰度明显低于农垦58的。没有检测到突变的atpB和其它形式的atpB转录产物。 分析P41和P61在其它水稻材料中的分布特点发现它们在粳型光敏不育系7001S、5088S、31301S、C407S和1647S，籼型光敏不育系W7415S和W9451S以及温（光）敏不育系培矮64S中存在，而在对照材料三系水稻马协A、珍汕97A、马协B、珍汕97B和明恢63以及常规粳稻C94153中不存在。根据这些不育系的系谱和它们与农垦58S之间基因的等位性研究结果，讨论了P41和P61与光敏核不育性的可能联系。

Reproductive biology of the blue spot mullet Valamugil seheli (Forskal) from Mangalore Region, southwest coast of India

The blue spot mullet Valamugil seheli spawns once a year between August and February with peak spawning during October - November. Males attain maturity at 250.5 mm and females at 256.5 mm total length. Males outnumbered females in the commercial catches, although the sex-ratio (M:F=1:0.90) in the population showed no significant deviation. The fecundity of this species varied from 108378 to 910350 eggs with an average of 327944. Linear relationships were found between fish length, gonad weight and fecundity; and between fish length, fish weight and ovary weight.

Systematic study of the blue green algae of Ceylon kept at the herbarium of the Royal Botanical Gardens, Peradeniya

The collection of blue green algae kept at the herbarium of the Royal Botanical Gardens, Peradeniya, was collected by Ferguson more than 70 years ago. Since then many changes have taken place in the taxonomy of the blue green algae. West (1902), Lemmermann (1907), Wine (1915), Crow (1923), Bharadwaja (1934) and Holsinger (1935) had described some of the blue green algae of Ceylon. While examining the collections of blue green algae kept at the herbarium, the authors found that most of the identifications were incorrect and required revision. In the present paper 20 blue green algae are described. The classification and key to the species are based on the characters given by Desikachary (1959). Blue green algae are important to fisheries since Chanos larvae feed on them.

Bimesogenic liquid crystals: New materials for high performance flexoelectric and blue phase displays

In this paper we will describe new bimesogenic nematic liquid crystals that have high flexoelectro-optic coefficients (e/K),of the order of 1.5 CN 1 m-1, high switching angles, up to 100° and fast response times, of the order of 100μs or less. We will describe devices constructed, using the ULH texture that may be switched to the optimum angle of 45° for a birefringence based device with the fields of 4Vμm-1 over a wide temperature range. Such devices use an "in plane" optical switching mode, have gray scale capability and a wide viewing angle. We will describe devices using the USH or Grandjean texture that have an optically isotropic "field off" black state, uses "in plane" switching E fields, to give an induced birefringence phase device, with switching times of the order of 20μs. We will briefly describe new highly reflective Blue Phase devices stable over a 50V temperature range in which an electric field is used to switch the reflection from red to green, for example. Full RGB reflections may be obtained with switching times of a few milliseconds. Finally we will briefly mention potential applications including high efficiency RGB liquid crystal laser sources. © 2006 SID.

Analysis of basic processes inside the keyhole during deep penetration ND-YAG CW laser welding

During laser welding, the keyhole is generated by the recoil pressure induced by the evaporation processes occurring mainly on the front keyhole wall (KW). In order to characterize the evaporation process, we have measured this recoil pressure by using a plume deflection technique, where the plume generated for static conditions (i. e. with no sample displacement) is deflected by a transverse side gas jet. From the measurement of the plume deflection angle, the recoil pressure can be determined as a function of incident intensity and sample material. From these data one can estimate the pressure generated on the front KW, during laser welding. Therefore, the corresponding dynamic pressure exerted by the vapor plume expansion on the rear KW, in contact with the melt pool, can be also estimated. These pressures appear to be in close agreement with those generated by an additional side jet that has been used in previous experiments, for stabilizing the observed melt pool oscillations or fluctuations.