Bait,habitat preferences and the phenology of some lesser dung flies (Diptera: Sphaeroceridae) in Britain

Two thousand eight hundred and sixty Sphaeroceridae representing 45 species were caught in eight traps, baited with horse, cow or hamster dung or carrion, placed in woodland and in the open at Silwood Park, Berkshire, during 1983/4. A list of the species and the numbers of each caught in each of the traps is given. Comparisons between the catches of open and woodland habitats and between the catches of the different baits used are made. The habitat and bait preferences and the phenologies of the dominant species are discussed.     

弱激光照射周氏新对虾心脏细胞的显微和超微结构观察

采用He-Ne激光照射周氏新对虾的心脏组织.组织学和生物统计学表明:He-Ne激光照射后,心脏组织具有明显异染色质的细胞数量有所增加.在同一照射强度的情况下,照射的时间越长,其心脏组织具有明显异染色质的细胞数量就越多;电镜观察结果表明:经过2 h照射立即取材的心肌细胞,细胞核形态发生变化,异染色质增加,线粒体出现空泡化、嵴断裂、水肿,粗面内质网出现扩张、颗粒脱落.     

拟穴青蟹细胞核DNA含量的测定

以拟穴青蟹(Scylla paramamosain)的血淋巴细胞为材料,刀额新对虾(Metapenaeus ensis)的血淋巴细胞为参照系,利用倍性分析仪结合外标定法测定其细胞核DNA含量.拟穴青蟹的血淋巴的细胞核DNA含量是2.677 pg/2c.此外,本文作者还发现拟穴青蟹血淋巴与肌肉组织细胞核DNA含量存在差异.报道了我国拟穴青蟹细胞核DNA含量,并且提供了拟穴青蟹的细胞遗传学特征,为蟹类系统重建与演化过程分析提供新资料.     

刀额新对虾精子发生过程中碱性蛋白的变化

采用氨银反应与光镜、电镜技术相结合，研究了刀额新对虾（Ｍｅｔａｐｅｎａｅｕｓｅｎｓｉｓ）成熟精子发生过程中碱性蛋白的变化．精原细胞、精母细胞、早期精细胞核内均含有丰富的碱性蛋白，但在精细胞变态成精子过程中，核内碱性蛋白被抛弃，顶体内出现碱性蛋白．且在成熟精子中内外顶体层碱性蛋白的分布不同，外顶体层多于内顶体层，棘突中无碱性蛋白存在．同时还探讨了鞭毛型精子和无鞭毛型精子之间的差异．     

刀额新对虾周期蛋白B基因的分子克隆及序列分析

周期蛋白B(cyclin B)是真核生物细胞周期的一种重要调控原件,通过调节周期蛋白依赖性蛋白激酶(cyclindependent kinase,CKD)的活性可以控制细胞周期.运用RACE(rapid-amplification of cDNA ends)技术克隆了刀额新对虾(Metapendeusensis)cyclin B基因.刀额新对虾cyclin B的cDNA全长为1681 bp,5′端非编码区为111 bp,3 ′端非编码区为355 bp,开放阅读框为1215 bp,编码404个氨基酸,平均分子质量为45767.9 u,pl为8.81.Blast比对后发现,其氧摹酸序列与斑节对虾(Penaeus monodon)的同源性达约90％.基于cyclin B序列所绘制的进化树基本上能反映出各物种间的进化关系.半定量RT-PCR结果显示,刀额新对虾的cyclinB基因在不同组织表达中具有明显的组织特异性,在鳃、卵巢和心脏中有较高的表达量,在眼柄神经节和胸神经节中表达量较低.推测该差异性主要与cyclin B在细胞周期中调控细胞分裂的功能有关.     

周氏新对虾有髓鞘神经纤维的超微结构

周氏新对虾(Metapenaeus joyneri)的有髓鞘神经纤维为椭圆型、圆型，椭圆型长轴直径40-65μm，短轴直径18-25μm．轴突直径6-10μm，位于髓鞘的一侧，轴突壁由微管组成．在轴突壁与膜层之间存在液体间隙．在液体间隙外的髓鞘厚约1μm，由3层膜层和2层微管层组成，在部分髓鞘的结构中，微管层增厚．在髓鞘结构中观察到高嗜锇性区域，由排列规则且明暗交替的膜层组成，     

刀额新对虾和日本囊对虾细胞核DNA含量的测定与比较

以刀额新对虾(Metapenaeus ensis)、日本囊对虾(Marsupenaeus japonicus)的血淋巴为材料,以小鸡血细胞核DNA含量(2.50 pg/2c)为参照样,使用Partec PA-I型倍性分析仪并结合外标定法,分别测定了刀额新对虾与日本囊对虾细胞的DNA含量.结果表明,这两种虾的细胞DNA含量分别为小鸡血细胞的1.77倍和1.95倍,换算成绝对含量分别为4.340 pg/2c和4.878 pg/2c.本文讨论了刀额新对虾与日本囊对虾以形态学为特征的分类系统与细胞DNA含量之间的关系,并推测在系统演化上日本囊对虾应比刀额新对虾更为高等.     

Occurrence and influence of Orbione halipori Nierstrasz and Brender à Brandis (Isopoda: Bopyridae) on Metapenaeus joyneri (Miers) (Decapoda: Penaeidae) from the Zhujiang estuary,China

The bopyrid parasite Orbione halipori was recorded for the first time from Metapenaeus joyneri. Morphometric analysis indicated that infested male and female shrimp have slightly, but significantly, lower body weight than uninfested shrimp of the same carapace length. While the parasites sterilize their hosts, the low infestation rate (0·53%) appears not to pose a threat to the shrimp fisheries in the Zhujiang estuary.     

Epibionts and parasites of Macrobrachium rosenbergii and Metapenaeus dobsoni from Gosthani estuary

Juveniles of two species of commercially important prawns, Metapenaeus dobsoni (Miers) and Macrobrachium rosenbergii (De Man) collected from Gosthani estuary, Bheemunipatnam near Visakhapatnam, India during the period August 1995 to August 1996 were subjected to a detailed study with a view to identifying the various species of epibionts and parasites and to monitor the seasonal changes in the occurrence and abundance of common species of ciliates and larval helminths. A wide range of protozoan and metazoan parasite species was encountered in the prawns. The protozoans were represented by epicommensal ciliates belonging to the genera Zoothamnium, Epistylis, Acineta, Vorticella, an unidentified apostome ciliate and two species of gregarines. The metazoan parasites included metacercariae of families Opecoelidae and Microphallidae, a larval cestode, a larval nematode and two species of bopyrid isopods. Altogether eight species were found infecting M. rosenbergii and 11 species infected M. dobsoni. A majority of the parasite species infected both the hosts. The peritrichous and apostome ciliates constituted the dominant members of the parasite fauna, occurring on both species of prawns as epibionts with high prevalence and density. All the other infections were rarely encountered. Infections with gregarines were restricted to M. dobsoni while those of microphallid metacercariae were found only in M. rosenbergii. Zoothamnium infections were more common on M. rosenbergii than on M. dobsoni. Apparent differences in the parasite fauna, attributed to differences in the behaviour of the two species, were noted. Seasonally Zoothamnium infections were at their peak during monsoon and post-monsoon months and these infections appear to be governed directly by salinity of the habitat and indirectly by the rainfall. Apostome ciliate infections were at their peak during the months November and February. Opecoelid metacercarial infections were confined to the period August to February, with peak during summer months.     

刀额新对虾复眼的外部形态结构及光、暗适应对其超微结构的影响

应用电镜技术观察了刀额新对虾复眼的形态结构以及光、暗适应对其超微结构的影响．结果表明，刀额新对虾复眼外形呈圆球形，约由93116个小眼组成，组成复眼的小眼面均为正方形．每个小眼由折光系统和感光系统组成．光、暗适应时折光系统的结构基本相同，但感光系统之间有较大的差异．暗适应时，组成感杆束的微纤毛排列整齐，膜下储泡囊数量多，体积大，色素颗粒仅分布在细胞体远端；而光适应时，组成感杆束的微纤毛排列凌乱，并有部分溶解，多囊体多，各个层面上有板膜体的出现，色素颗粒分布于整个细胞．