Division of labor in the monogamous goby,Valenciennea longipinnis, in relation to burrowing behavior

Feeding and burrowing behavior of the monogamous gobiid fish,Valenciennea longipinnis, were studied on the coral reef at Sesoko Island, Okinawa, Japan. These fish usually live in pairs, the male and female feeding in close proximity to one another upon benthic animals and constructing several burrows cooperatively for purposes of shelter or spawning. Paired females fed more and burrowed less frequently than their mates. Because burrow maintenance was mostly conducted by the latter, the paired females performed work much less frequently than solitary females. Thus, the paired females may be able to allocate more energy toward egg production. The division of labor related to burrowing behavior in this species may be an effective way to increase reproductive success for both sexes. Moreover, the fameles burrowed even less frequently when paired with larger males, probably because burrowing ability may be correlated with mouth size in males. This is a likely reason for the preference of females to mate with larger males.     

Regulation of foreign DNA uptake by mouse spermatozoa

We have studied some features of DNA uptake in both mature and immature mammalian spermatozoa. Mature sperm collected from the cauda epididymis are able to incorporate foreign DNA in a buffer containing only salts and calcium. Immature spermatozoa, however, are unable to bind DNA. This seems to be caused by the lack of a functional receptor in the sperm membrane since once this membrane is disrupted by sonication, DNA can be detected in the postacrosome region of the sperm nucleus, matching the distribution of the mature spermatozoa. Comparison between the DNA binding proteins of mature and immature spermatozoa allowed us to identify two bands that could be part of the putative membrane receptor for the DNA. On the other hand, DNA uptake in mature sperm is prevented by the seminal plasma. We have identified two components of the seminal plasma, a calcium-dependent DNase present in the seminal vesicle fluid and several DNA binding proteins secreted by the ventral prostate, that could account for the inhibitory activity. Taken as a whole, our results indicate that DNA uptake by the mammalian spermatozoa is a very specific and highly regulated phenomenon.     

Morphology of the male reproductive system of, Coralliozetus angelica (Pisces, Blennioidei, Chaenopsidae)

The testis, the seminal vesicles and the spermatic duct of Coralliozetus angelica (Böhlke & Mead) are described. The testis and the seminal vesicles are not arranged in pairs but are single. The testis is situated on the left side of the animal and consists of chambers instead of tubules. The seminal vesicle on the right side is composed of two different types (seminal vesicle 1 and 2) which are not connected with each other     

Tissue specific regulation of prostaglandin production stimulation of 6-ketoprostaglandin F1α biosynthesis by rat kidney cytosol

Boiled cytosol of various rat tissues each affected prostaglandin biosynthesis by bovine seminal vesicle microsomes in a specific way. Kidney cytosol enhanced 6-ketoprostaglandin F_1α production in a dose-dependent manner. This stimulatory effect was lost after dialysis. Liver, spleen and carrageenin granuloma cytosol inhibited 6-ketoprostaglandin F_1α production but enhanced prostaglandin E₂ production.     

Effects of molybdenum on fertility of male rats

Sodium molybdate was administered orally to adult male rat at dose level of 10, 30, and 50 mg kg body weight (5 days per week) for 60 days. At higher dose levels significant decrease in absolute and organ-to-body weight ratios of testes, epididymides, seminal vesicles and ventral prostate was observed. The sperm abnormality, associated with decrease in sperm motility and sperm count was also observed. Significant alterations in the activities of marker testicular enzymes, viz. sorbitol dehydrogenase (decreases), lactate dehydrogenase (increases) and -glutamyl transpeptidase (increases) associated with histopathological changes in testes was also observed. Accumulation of molybdenum in testes, epididymides and seminal vesicles was also observed. The study reveals that the oral ingestion of molybdenum may affect the histoarchitecture of testes and sperm morphology. The testicular and spermatotoxic changes may be responsible for observed male mediated developmental toxic effects.     

哺乳动物精浆胞外囊泡及各组分的功能

精浆胞外囊泡是一种存在于精浆的膜性囊泡,按分泌器官分为附睾小体和前列腺小体。囊泡可与精子细胞膜发生融合,通过传递内容物或介导信号通路进而调节精子功能。它含有多种活性物质,其中蛋白质组分可影响精子活力以及顶体反应,并有清除损伤精子和促进细胞粘附的作用;脂质组分具有调节靶细胞质膜稳定性的作用;核酸组分主要参与免疫反应、跨代遗传及男性不育;离子则是多种酶的辅助因子,在调节酶活性和精浆微环境中发挥重要作用。不同组分对精子功能的影响不尽相同,本文将对此方面的研究进展进行详尽的综述,以期为该领域相关研究人员提供一定的参考。     

Polymorphism at the avpr1a locus in male prairie voles correlated with genetic but not social monogamy in field populations

Integrative studies of genetics, neurobiology and behaviour indicate that polymorphism in specific genes contributes to variation observed in some complex social behaviours. The neuropeptide arginine vasopressin plays an important role in the regulation of a variety of social behaviours, including social attachment of males to females, through its action on the vasopressin 1a receptor (V1aR). In socially monogamous prairie voles ( Microtus ochrogaster ), polymorphism in the length of microsatellite DNA within the regulatory region of the gene ( avpr1a ) encoding the V1aR predicts differences among males in neural expression of V1aRs and partner preference under laboratory conditions. However, understanding the extent to which V1aR mediates variation in prairie vole social and reproductive behaviour observed in nature requires investigating the consequences of avpr1a polymorphism and environmental influences under ecologically relevant conditions. We examined the relationship between avpr1a length polymorphism and monogamy among male prairie voles living in 0.1 ha enclosures during a time similar to their natural lifespan. We found no evidence that avpr1a genotype of males predicts variation in social monogamy measured in the field but some indices of social monogamy were affected by population density. Parentage data indicated that a male's avpr1a genotype significantly influenced the number of females with which he sired offspring and the total number of offspring sired. Total brain concentrations of V1aR mRNA were not associated with either male behaviour or avpr1a genotype. These data show that melding ecological field studies with neurogenetics can substantially augment our understanding of the effects of genes and environment on social behaviours.     

Drosophila bipectinata species complex: study of phylogenetic relationship among four members through the analysis of morphology of testes and seminal vesicles

Species maintain their identity through reproductive isolating mechanisms, which are broadly classified into prezygotic and postzygotic isolating mechanisms. In the Drosophila bipectinata species complex, investigations were made on the degree of crossability (a prezygotic isolating mechanism) and the causes of hybrid male sterility (a postzygotic isolating mechanism) to analyse the phylogenetic relationship. Among the four species, D. bipectinata crosses with Drosophila parabipectinata freely in one direction and both of them also cross with Drosophila malerkotliana easily but it is difficult to cross all the three species with Drosophila pseudoananassae . In the hybrids involving D. pseudoananassae , no sperm were observed indicating high degree of perturbance during spermatogenesis while in the other hybrids immotile sperm were present indicating comparatively less disturbance during spermatogenesis. Testis size, which is an indicator of degree of perturbance during spermatogenesis and used as a proxy for sterility was measured in the four species and their hybrids. It was of same size in D. bipectinata , D. parabipectinata and D. malerkotliana but larger in D. pseudoananassae . In the hybrids involving D. pseudoananassae , testes were atrophied while in other hybrids it was larger. Since, the size of testis does not exhibit uniform pattern of variation in hybrids, it cannot be used as a good indicator for sterility. Therefore, we also measured the size of seminal vesicles (storing organ of sperm) in the four species and their hybrids. Interestingly, the size of seminal vesicles was reduced uniformly in all the hybrids indicating its use as better proxy for sterility. Further, the seminal vesicle size in D. pseudoananassae was smaller than that in the other three species. These observations provide evidence for phylogenetic proximity of D. bipectinata , D. parabipectinata and D. malerkotliana and their remote relationships with D. pseudoananassae .     

Shelter utilization by Gobius cruentatus and Thorogobius ephippiatus (Teleostei: Gobiidae)

Parameters of shelters utilized by Gobius cruentatus and Thorogobius ephippiatus were measured, in situ , using SCUBA. Both species exhibited non-random use of shelters, with T. ephippiatus , the smaller of the two species, utilizing significantly larger shelters than G. cruentatus . Interspecific size differences and competitive exclusion are not considered to be of major importance in the observed differential utilization of shelters. The size of shelters utilized by both species is suggested to be influenced by current velocities.     

A redescription of <Emphasis Type="Italic">Cryptocentrus crocatus</Emphasis> Wongratana,a redefinition of <Emphasis Type="Italic">Myersina</Emphasis> Herre (Acanthopterygii; Gobiidae), a key to the species,and comments on relationships

Myersina is redefined, based on the presence of an elongate first dorsal fin in at least the adult males, two preopercular pores, gill membranes fused in the ventral midline and either fused to the isthmus or forming a free fold over it, cycloid scales only on the body, and midline of predorsal region scaleless. It now includes four species traditionally assigned to Cryptocentrus but here placed in Myersina ("C". crocatus, "C". filifer, "C". pretoriusi, and "C". yangii). This concept of Myersina still retains the species originally assigned to it (M. macrostoma, M. lachneri, and M. nigrivirgata). The recently described M. larsonae belongs in Stonogobiops. These two genera almost definitely form a monophyletic group. However, it is possible that the species of Stonogobiops (the monophyly of which is well supported) could be more closely related to one or more species of Myersina than either is to other Myersina species, because the monophyly of the latter genus remains uncertain. Received: March 23, 2001 / Revised: September 7, 2001 / Accepted: October 18, 2001