Expression of the male reproduction-related gene (Mar-Mrr) in the spermatic duct of the giant freshwater prawn, Macrobrachium rosenbergii

Phosphorylated sperm proteins are crucial for sperm maturation and capacitation as a priori to their fertilization with eggs. In the freshwater prawn, Macrobrachium rosenbergii, a male reproduction-related protein (Mar-Mrr) was known to be expressed only in the spermatic ducts as a protein with putative phosphorylation and may be involved in sperm capacitation in this species. We investigated further the temporal and spatial expression of the Mar-Mrr gene using RT-PCR and in situ hybridization and the characteristics and fate of the protein using immunblotting and immunocytochemistry. The Mar-Mrr gene was first expressed in 4-week-old post larvae and the protein was produced in epithelial cells lining the spermatic ducts, at the highest level in the proximal region and decreased in the middle and distal parts. The native protein had a MW of 17 kDa and a high degree of serine/threonine phosphorylation. It was transferred from the epithelial cells to become a major protein at the anterior region of the sperm. We suggest that it is involved in sperm capacitation and fertilization in this open thelycal species and this is being investigated.     

Gene duplication and adaptive evolution of digestive proteases in Drosophila arizonae female reproductive tracts

It frequently has been postulated that intersexual coevolution between the male ejaculate and the female reproductive tract is a driving force in the rapid evolution of reproductive proteins. The dearth of research on female tracts, however, presents a major obstacle to empirical tests of this hypothesis. Here, we employ a comparative EST approach to identify 241 candidate female reproductive proteins in Drosophila arizonae, a repleta group species in which physiological ejaculate-female coevolution has been documented. Thirty-one of these proteins exhibit elevated amino acid substitution rates, making them candidates for molecular coevolution with the male ejaculate. Strikingly, we also discovered 12 unique digestive proteases whose expression is specific to the D. arizonae lower female reproductive tract. These enzymes belong to classes most commonly found in the gastrointestinal tracts of a diverse array of organisms. We show that these proteases are associated with recent, lineage-specific gene duplications in the Drosophila repleta species group, and exhibit strong signatures of positive selection. Observation of adaptive evolution in several female reproductive tract proteins indicates they are active players in the evolution of reproductive tract interactions. Additionally, pervasive gene duplication, adaptive evolution, and rapid acquisition of a novel digestive function by the female reproductive tract points to a novel coevolutionary mechanism of ejaculate-female interaction.     

Transfer and fate of male ejaculate in female Queensland fruit flies

Abstract Insect seminal fluid commonly comprises a complex cocktail of proteins and other biochemical components that migrate away from the female reproductive tract to sites elsewhere in the female body and elicit changes in female reproductive behaviour. The transfer of male seminal fluid molecules to reproductive and somatic tissues of the female Queensland fruit fly (‘Q‐fly’) Bactrocera tryoni is examined and some putative target sites identified. Male Q‐flies are fed a diet containing radiolabelled (³⁵S) amino acids, which are incorporated into male accessory gland products. Radioactivity diminishes within the accessory glands and increases in all assessed parts of the female body during copulation, indicating the transfer of these products into the female soma via the reproductive tract. There are significant changes in the absolute and proportional radioactivity profiles among female tissues over the next 22 h, with substantial reductions in the thorax and increases in the head. This is consistent with accumulation of behaviour‐modifying male products at binding sites in the female head. Parallels can be drawn between the data in the present study and seminal fluid distribution profiles and receptor binding documented in other insects.     

Amino acid content of preimplantation rabbit embryos and fluids of the reproductive tract

As a companion to amino acid transport and protein synthetic studies, it was of interest to quantify the amino acid pools in embryos and reproductive tract fluids during preimplantation development. Primary amines in the acid-soluble extracts of embryo and fluid samples were separated by high-performance liquid chromatography, reacted with o-phthalaldehyde, and quantified by fluorescence emission. The amino acid compositions of embryos were like those of corresponding reproductive tract fluids. Taurine was high in eggs and fluids but declined with development, while glycine levels rose. Glycine was highest in concentration in all samples (except the egg), followed by glutamate and alanine, while most other amino acids were consistently of low abundance.     

Proteolytic processing of mullerian inhibiting substance produces a transforming growth factor-beta-like fragment

Mullerian inhibiting substance (MIS) is a differentiation factor that causes the Mullerian duct to regress during the development of the male reproductive tract. The active form is a disulfide-linked dimer consisting of two identical 70-kDa subunits. Recently, the amino acid sequence for MIS was deduced from its gene sequence and revealed that the carboxyl-terminal region shares homology with transforming growth factor (TGF)-beta. Since TGF-beta is produced as a large latent precursor that requires proteolytic activation for activity, we sought to determine if MIS might undergo a similar processing event. Here we demonstrate that typically 5 to 20% of the protein in MIS preparations is cleaved at a site 109 amino acids from the carboxyl terminus. Concurrent cleavages from both chains of the MIS dimer produces a 25-kDa TGF-beta-like fragment and a high molecular mass complex derived from the amino terminus of the protein. Although the two fragments are noncovalently linked, they remain tightly associated after cleavage, and thus are structurally organized like TGF-beta within its precursor. The same cleavage products also can be generated by limited proteolysis with plasmin, which provides a simple method for converting the entire preparation into the cleaved form. The plasmin-digested MIS is fully active in the organ culture assay.     

Introduced fire ants can exclude native ants from critical mutualist-provided resources

After over 30 years of research, it was recently shown that nectar amino acids increase female butterfly fecundity. However, little attention has been paid to the effect of nectar amino acids on male butterfly reproduction. Here, we show that larval food conditions (nitrogen-rich vs. nitrogen-poor host plants) and adult diet quality (nectar with or without amino acids) affected the amount of consumed nectar in Coenonympha pamphilus males. Furthermore, amino acids in the nectar diet of males increased progeny’s larval hatching mass, irrespective of paternal larval reserves. Our study takes the whole reproductive cycle of male butterflies into account, and also considers the role of females in passing male nutrients to offspring, as males’ realized reproduction was examined indirectly via nuptial gifts, by female performance. With this comprehensive approach, we demonstrate for the first time that nectar amino acids can improve male butterfly reproduction, supporting the old postulate that nectar amino acids generally enhance butterfly fitness.     

性腺发育不同阶段野生瓯江凤鲚肌肉营养成分的分析与评价

研究旨在针对不同性腺发育阶段(Ⅰ期、Ⅱ期、Ⅲ期、Ⅳ期、Ⅴ期)野生瓯江凤鲚(Coiliamystus)性腺发育情况和肌肉营养成分进行分析与评价。研究表明:在雌、雄野生瓯江凤鲚性腺从Ⅰ期发育至Ⅴ期的过程中,成熟系数呈现上升趋势,凤鲚卵巢的GSI值是精巢GSI值的5倍。在卵巢发育Ⅰ—Ⅴ期,粗脂肪含量显著下降,粗蛋白和水分显著上升(P<0.05);在精巢发育Ⅰ—Ⅴ期,粗脂肪含量显著上升,粗蛋白和水分显著下降(P<0.05),灰分含量先升后降,说明野生瓯江凤鲚在卵巢发育过程中脂肪为主要供能物质。雌凤鲚肌肉在卵巢发育Ⅰ—Ⅴ期显著上升(P<0.05),雄凤鲚肌肉氨基酸含量在精巢发育Ⅰ—Ⅴ期显著下降(P<0.05)。但各性腺发育阶段氨基酸组成相对稳定,雌、雄鱼肌肉总必需氨基酸/总氨基酸分别为(37.88±0.32)%—(41.66±0.44)%和(40.30±0.69)%—(40.94±0.29)%。依据氨基酸评分(AAS)和化学评分(CS)标准,不同性腺发育阶段的野生瓯江雌、雄凤鲚肌肉中第一限制性氨基酸均为色氨酸,第二限制性氨基酸均为甲硫氨酸(Met)和胱氨酸(Cys)。在卵...     

MROS1, a Male Stamen-Specific Gene in the Dioecious Campion Silene latifolia Is Expressed in Mature Pollen

The MROS1 gene, one of the genes that are expressed specificallyin male reproductive organs of a dioecious campion Silene latifolia,was predicted to encode only 36 amino acids but have an intron.In situ hybridization revealed that MROS1 mRNA was localizedin mature pollen grains. (Received January 30, 1997; Accepted February 24, 1997)     

Evolution of the expression of the Gld gene in the reproductive tract of Drosophila.

During the preadult development of Drosophila melanogaster, the GLD (glucose dehydrogenase) gene (Gld) is expressed in a variety of tissues, including the immature reproductive tract. At the adult stage the expression of Gld becomes largely restricted to the reproductive tract of males and females. We examined the expression of GLD in the adult reproductive tract of 50 species in the genus Drosophila, as well as in those of a few representative species from four other closely related genera. GLD exhibits considerable organ-specific diversity in the reproductive tract of males and females. Among these species, five male GLD phenotypes and six female GLD phenotypes were found. In contrast, the preadult expression of GLD in representative species from each distinct adult pattern type was determined and found to be highly conserved in both the immature reproductive tract and non-reproductive organs. Moreover, the set of reproductive organs that express GLD during preadult development is equivalent to the sum of the five male and six female adult GLD phenotypes. To initially define the contribution of cis- versus trans-acting factors responsible for differences in adult GLD expression between two of these species--D. melanogaster and D. pseudoobscura--we transferred the D. pseudoobscura Gld to the genome of D. melanogaster and investigated its expression. GLD expression patterns of these transformants displayed characteristics that are unique to both species, suggesting the presence of both cis- and trans-acting differences between these two species.     

Diversity-enhancing selection acts on a female reproductive protease family in four subspecies of Drosophila mojavensis

Protein components of the Drosophila male ejaculate are critical modulators of reproductive success, several of which are known to evolve rapidly. Recent evidence of adaptive evolution in female reproductive tract proteins suggests this pattern may reflect sexual selection at the molecular level. Here we explore the evolutionary dynamics of a five-paralog gene family of female reproductive proteases within geographically isolated subspecies of Drosophila mojavensis. Remarkably, four of five paralogs show exceptionally low differentiation between subspecies and unusually structured haplotypes that suggest the retention of old polymorphisms. These gene genealogies are accompanied by deviations from neutrality consistent with diversifying selection. While diversifying selection has been observed among the reproductive molecules of mammals and marine invertebrates, our study provides the first evidence of this selective regime in any Drosophila reproductive protein, male or female.     

Identification and characterization of Wfdc gene expression in the male reproductive tract of the rat

WFDC (Whey Acidic Protein Four Disulfide Core)-containing proteins have been reported in many species, yet they remain uncharacterized in the rat. In this study, we report the identification and characterization of four rat Wfdc genes, Wfdc6a, Wfdc8, Wfdc11 and Wfdc16. Their expression profile in a variety of tissues including the male reproductive tract is analyzed. Wfdc8, Wfdc11 and Wfdc16 expression is confined to the epididymis, while Wfdc6a is expressed widely. Since gene expression in the male reproductive tract is largely androgen-dependent, Wfdc expression was analyzed in the developing (20-60-day-old) and castrated rats. Their expression pattern in developing rats does not correlate with changes in testosterone. Wfdc genes are, however, down-regulated in castrated adult rats, indicating that their dependence on androgens for expression is more pronounced in the adult than in the developing rat. To test the anti-microbial potential of WFDC8, a recombinant WFDC8 C-terminal protein was produced, which exhibited potent anti-bacterial activity against Eschericia coli. Induction of anti-microbial genes is one of the responses during infections in many organ systems. To determine if WFDCs form the components of male reproductive tract innate immunity, Wfdc8 expression pattern was observed in rats challenged with lipopolysaccharide (LPS). For the first time we report the induction of Wfdc8 gene expression in LPS-treated rats, indicating their contributions to the innate immune functions of the male reproductive tract.     

Characterization of a novel lysozyme-like 4 gene in the rat

Lysozyme-like proteins (LYZLs) belong to the class of c-type lysozymes and are not well characterized in many species including the rat. In this study, using in silico and molecular biology techniques, we report the identification, cloning and characterization of rat Lyzl4 gene and also determine the expression pattern of Lyzl1, Lyzl3 and Lyzl6. The rat Lyzl genes were found to be distributed on three chromosomes and all of them retained the characteristic eight cysteine signature of c-type lysozyme. Homology modeling of rat LYZL4 indicated that its structure is similar to that of the mouse SLLP1. In the male reproductive tract of rat, Lyzl gene expression was confined to the testis. Lyzl1 and Lyzl4 were found to be expressed in tissues beyond the male reproductive tract, whereas Lyzl3 and Lyzl6 were not. Lyzl expression in the developing (10-60 day old) rats was androgen dependent in the testis. Immunodetection using antibodies against rat LYZL4 revealed the presence of LYZL4 protein in the germinal layer of the testes and on the sperm tail. Recombinant LYZL4 did not exhibit antibacterial, muramidase and isopeptidase activities characteristic to c-type lysozyme. To the best of our knowledge, for the first time we report the characterization of Lyzl genes in the rat. Results of our study indicate that rat LYZL proteins may have an important role in male reproductive tract function.     

cDNA cloning, sequence analysis and tissue distribution of a precursor for vasoactive intestinal contractor (VIC)

A full-length cDNA encoding preprovasoactive intestinal contractor (PPVIC) has been cloned. From the deduced 160 amino acid PPVIC, the mature VIC is predicted to be produced via a 37 residue intermediate, big VIC. The PPVIC also contains a VIC-like peptide of 16 amino acids structurally related to to the amino-terminal residues of VIC and flanked by pairs of dibasic amino acids, putative processing sites. RNA blot hybridization with PPVIC cDNA confirmed the PPVIC gene to be expressed in the small and large intestinal tract in a tissue specific manner.     

Does the lateral bundle of the medial olfactory tract mediate reproductive behavior in male crucian carp?

The olfactory tract in crucian carp (Carassius carassius) is divided into three distinct bundles: the lateral tract (LOT) and the lateral (lMOT) and medial (mMOT) bundles of the medial tract. The LOT has been shown to mediate information associated with feeding behavior, whereas the mMOT mediates information associated with alarm response. The role of the medial olfactory tract (lMOT and mMOT) in reproductive behavior is still under debate. In the present experiment, male reproductive behavior towards prostaglandin-injected females was investigated before and after cutting off the different olfactory tract bundles, to determine which of the tract bundles is essential for mediating reproductive behavior in male crucian carp. The fish were maintained in physiological saline before and after surgery to preserve the remaining tract bundles. Operations were performed symmetrically on both sides and post-operative inspections revealed the functionality of the intact tracts. Sham-operated males and males with only the lMOT intact showed typical reproductive behavior, with following of the female and inspections of the female anal papilla. However, males in which the lMOT was cut, leaving both the mMOT and the LOT intact, showed reduced reproductive behavior. Our results suggest that the lMOT mediates reproductive behavior in male crucian carp.