Variation in the free amino acid content of ovary, hepatopancreas and hemolymph of Penaeus schmitti during ovarian maturation (Crustacea, Decapoda, Penaeidae)

Quantitative and qualitative variations of free-amino-acids contents (FAA) of ovaries, hepatopancreas and haemolymph have been studied in the course of ovarian maturation in Penaeus schmitti. In the ovary, FAA content, expressed as microM/g ovary fresh weight, decreases from 56.2 to 23.6 microM between gonadosomatic index (GSI) 0.8 and GSI 7.1. There is an increase of hepatopancreas FAA content of 33.4% till GSI 4. Haemolymph FAA content increases from 0.32 to 1.76 microM/ml, with maximal values of 3.74 microM/ml when GSI are between 3 and 4. FAA content of ovaries, expressed as microM/g of animal, is 3.2 fold higher at the end of maturation, with a main increase in the first stages of ovogenesis. Maturation process has a quantitative effect on all FAA, but, on a qualitative point of view, it concerns mainly lysine, arginine and glycine. The main variations of AA composition (expressed as percentage of total FAA) are observed in haemolymph.     

Biochemical composition of ovary, embryo, and hepatopancreas in the grapsoid crabs Armases cinereum and Sesarma nr. reticulatum (Crustacea, Decapoda)

Biochemical composition of ovary, embryo, and hepatopancreas tissues in wild populations of Armases cinereum and Sesarma nr. reticulatum were monitored during the reproductive season. Total lipid, carbon, nitrogen, C:N ratio, and water concentration of the ovary, hepatopancreas and embryos were quantified over the course of ovarian maturation. Ovary nitrogen concentration decreased as ovaries matured. Ovary lipid and carbon concentration differed significantly over the course of ovarian maturation for both species, but there was no relationship between the concentration or total content of hepatopancreas lipid and the stage of ovarian development in females. Neither species showed a relationship between measures of hepatopancreas lipid and the gonadosomatic index. There was also no simultaneously measurable net decrease in mass of the females' hepatopancreas. Lipid demands of ovarian maturation thus appear to be met in large part by increased dietary intake rather than by substantial draw down of pre-existing lipid stores from the hepatopancreas. While these temperate grapsoid crabs live with putatively fluctuating quality and quantity of food resources, no evidence could be found to demonstrate depletion of lipid concentrations in the hepatopancreas concomitant with ovarian maturation.     

Localization of vitellogenin mRNA expression and vitellogenin uptake during ovarian maturation in the giant freshwater prawn Macrobrachium rosenbergii

In situ hybridization and immunohistochemical techniques were used to investigate the dynamics of vitellogenin (Vg) mRNA expression and Vg uptake during ovarian maturation in the hepatopancreas and ovary at differing stages of ovarian maturation in both intact and eyestalk ablated female Macrobrachium rosenbergii. In the hepatopancreas of intact animals, Vg mRNA expression was detected faintly two days after ecdysis, and signals showed a gradual increase as the molt cycle advanced to the premolt stages, but decreased at the late premolt stage. Vg mRNA was detected in the R-cells of the hepatopancreas, indicating that these cells are responsible for synthesizing Vg. No Vg mRNA expression was observed in the ovary. Immunohistochemistry results for the hepatopancreas showed a pattern of staining intensity similar to that of in situ hybridization. Increases in the accumulation of yolk protein in the oocytes occurred concomitantly with increasing Vg mRNA expression. In eyestalk ablated animals, Vg mRNA expression and Vg uptake showed similar but accelerated patterns to those of intact animals. This study has confirmed on the cellular level previous results that Vg synthesis is intrinsically correlated to ovarian maturation and the molt cycle in M. rosenbergii.     

In vitro effect of methyl farnesoate on the vitellogenin content of ovary and hepatopancreas,in the crayfish Cherax quadricarinatus

Vitellogenin levels were determined in pieces of either ovary or hepatopancreas taken from females of the crayfish Cherax quadricarinatus during both early pre-reproductive and reproductive periods, and exposed in vitro to 0.15, 1.5, or 15?µM of the juvenoid methyl farnesoate (MF). A significant accumulation of vitellogenin was seen in ovaries treated with 15?µM of MF during the early pre-reproductive period. Besides, protein synthesis, measured as tritiated leucine incorporation, was correspondingly increased in ovaries taken during both pre- and post-reproductive periods and exposed to 15?µM of MF. On the other hand, no stimulating effect of MF on the vitellogenin content of the hepatopancreas was seen in any period. These results, taken together, support the hypothesis of the endogenous vitellogenin synthesis stimulated by MF during the early ovarian maturation. However, this hormone was not able to stimulate vitellogenin synthesis in the ovary during the reproductive period.     

三疣梭子蟹卵巢发育过程中主要类胡萝卜素组成变化及其与抗氧化性能的关系

实验研究了三疣梭子蟹(Portunus trituberculatus)卵巢发育过程中(Ⅰ—V期)组织色泽、类胡萝卜素组成与含量、抗氧化和非特异性免疫指标的变化规律,进一步探讨了肝胰腺中类胡萝卜素含量变化与抗氧化指标的关系。结果表明:(1)卵巢发育期间,卵巢指数(GSI)显著增加(P<0.05),肝胰腺指数(HSI)整体呈先升后降的趋势;卵巢的红度(a*)值和黄度(b*)值、肝胰腺的亮度(L*)值和b*值均呈显著上升趋势,但卵巢中L*值呈下降趋势。(2)在卵巢发育过程中,卵巢中的总类胡萝卜素、虾青素、叶黄素和β-胡萝卜素含量均为先升后降的趋势,虾青素含量在Ⅳ期最高;肝胰腺中的虾青素含量呈上升趋势,而β-胡萝卜素含量为显著下降趋势;内表皮中的总类胡萝卜素、虾青素、叶黄素、海胆烯酮和β-胡萝卜素含量均呈现下降趋势;就不同组织中类胡萝卜素含量而言,内表皮中虾青素含量最高。卵巢和肝胰腺的L*值与总类胡萝卜素含量呈显著负相关,卵巢的a*值和b*值均与总类胡萝卜素、虾青素、叶黄素、海胆烯酮和β-胡萝卜素含量呈显著正相关。肝胰腺的a*值与各类胡萝卜素含量无显著相关性, b*值仅与虾青素含量呈显...     

Variation in lipid composition of Chinese mitten-handed crab, Eriocheir sinensis during ovarian maturation

This experiment was conducted to investigate the variation in lipid composition during the ovarian maturation of the crab Eriocheir sinensis. The Chinese mitten-handed crab broodstock was divided into six different maturation periods according to the size and color of ovary. Ovary, hepatopancreas, muscle, and hemolymph of broodstock in different maturation periods were analyzed for total lipid and fatty acids using gas chromatography, and lipid classes by thin-layer chromatography. The ovarian lipid concentration (expressed as percent wet ovarian weight) increased steadily from stage II (5.4%) to stage IV (19.1%), and decreased to the lowest levels after spawning (stage V, 6.6%). The hepatopancreatic lipid concentration (expressed as percent wet hepatopancreatic weight) increased with maturity of the ovaries, reached a maximum at stage III(2) (29.9%), and decreased during the subsequent period to spawning (16.7%). The muscular and hemolymph lipid concentration did not change markedly during the ovarian development. These results suggest the possible movement of hepatopancreatic lipids to the ovaries during the ovarian maturation. Both triacylglycerol and phosphatidylcholine were responsible for the increase in ovarian lipid concentration during sexual maturation. The fatty acids of total lipid, triacylglycerol, and phosphatidylcholine of the ovaries did not vary systematically during the ovarian maturation, but the ratio between n-3PUFA (polyunsaturated fatty acid) and n-6PUFA did change regularly with the ovarian lipid. These suggest that enough PUFA, especially n-3PUFA, should be supplied to the crab during ovarian maturation.     

Characterization of vitellin from the ovaries of the banana shrimp Litopenaeus merguiensis

Vitellin (Vt) was purified from ovary extracts of mature females of the banana shrimp Litopenaeus merguiensis using DEAE-Sephacel and Superdex 200 columns. Native Vt had an apparent molecular mass of 398 kDa as determined by native PAGE and by gel filtration chromatography. Under reducing and denaturing conditions (SDS-PAGE), Vt is composed of two major subunits of 87 and 78 kDa, although some faint bands were also detected. The N-terminal 10 amino acids sequence of the 78 kDa subunit is identical to that of Litopenaeus vannamei Vt and very similar to that of Litopenaeus japonicus vitellogenin (Vg) as well as Litopenaeus semisulcatus Vt, with an identity of 89%. Anti-Vt polyclonal antibody raised against purified Vt shows a high specificity with only ovarian Vt and hemolymph Vg of vitellogenic shrimps in double immunodiffusion and Western blot assays. Vg and Vt concentrations in hemolymph, hepatopancreas and ovaries were measured by ELISA. Vg concentrations increased in the hemolymph in the early stages of ovarian development and declined in the maturation stages. As there were undetectable concentrations of Vg in the hepatopancreas while an elevation of Vg levels occurred in the hemolymph, during the time that Vt was accumulating in the ovaries during oogenesis, this would suggest that the contribution of Vg synthesized by the hepatopancreas only might be not sufficient for adequate development of the oocytes in the banana shrimp L. merguiensis during vitellogenesis.     

Vitellogenin gene expression and hemolymph vitellogenin during vitellogenesis, final maturation, and oviposition in female kuruma prawn, Marsupenaeus japonicus

In penaeid shrimps, vitellogenin (VTG), the precursor of vitellin, is synthesized in the ovary and hepatopancreas and accumulated in oocytes during ovarian development. In the present study, VTG gene expression levels and hemolymph VTG levels were determined throughout ovarian development in female kuruma prawn, Marsupenaeus japonicus. Hemolymph VTG levels and VTG mRNA levels in the ovary and hepatopancreas were high during vitellogenesis, remained high until final maturation, and then decreased after oviposition. This profile suggests that VTG synthesis activity increases during vitellogenesis and decreases after oviposition. Absence of a significant increase in ovary size in final maturation suggests cessation of yolk accumulation and low activity of VTG synthesis in spite of high VTG mRNA levels. VTG mRNA levels in ovary and hepatopancreas were both highly correlated during vitellogenesis. Thus, their contribution to yolk accumulation seems to be similar. In contrast, VTG mRNA levels in the hepatopancreas increased more slowly at the start of vitellogenesis and declined more sharply after oviposition than in the ovary. This suggests a difference in the regulation of VTG synthesis between the ovary and the hepatopancreas.     

Dynamics of vitellogenin mRNA expression and changes in hemolymph vitellogenin levels during ovarian maturation in the giant freshwater prawn Macrobrachium rosenbergii

The dynamics of vitellogenin mRNA expression during ovarian maturation in Macrobrachium rosenbergii were examined by measuring hemolymph vitellogenin (Vg) levels and Vg mRNA expression in the hepatopancreas and ovary at differing reproductive stages in both intact and eyestalk ablated animals. Vg mRNA was quantified using real-time RT-PCR and hemolymph Vg was measured by enzyme immunoassay. In intact animals, Vg mRNA levels in the hepatopancreas and hemolymph Vg levels showed a gradual increase during the molt cycle concomitant with increasing gonadosomatic index (GSI), with Vg levels decreasing prior to ecdysis although GSI continued to increase. Eyestalk ablation was seen to accelerate Vg synthesis as well as ovarian maturation, although it did not alter the overall pattern of Vg expression. Vg mRNA expression was negligible in the ovary of both intact and eyestalk ablated animals, confirming that the hepatopancreas is the principal site of Vg synthesis in M. rosenbergii with the ovary being only a minor contributor. This study has shown that Vg synthesis is correlated to ovarian maturation and the molt cycle in M. rosenbergii.     

Ovarian and fat body protein concentrations in Ips sexdentatus (Coleoptera: Scolytidae) parasitized by nematodes

The protein concentrations of fat body and ovaries in Ips sexdentatus either uninfected or infected by Parasitaphelenchus sp., P. sexdentati, or Contortylenchus diplogaster were measured at various stages of insect development, from preswarming maturation to the first oviposition (24 hr after mating). Weight variations of the fat body and ovaries in insects infected by C. diplogaster show the same evolution as those observed in uninfected insects, but at a much lower level. Fat body proteins in uninfected insects reach their minimum level during swarming, but they remain fairly constant throughout the maturation of the first egg. After dropping shortly after swarming, the ovarian protein level in such insects increases in two stages during ovarian maturation. The first stage, which corresponds to a slow protein incorporation, takes place during the first 12 hr after mating. During the second stage, i.e., beyond 12 hr, a significant level of proteins is rapidly incorporated into the ovaries. In insects infected by Parasitaphelenchus fat body proteins are reduced and protein incorporation into the ovaries is reduced; Parasitaphelenchus would thus affect at least some proteins required for ovarian maturation in their host. Fat body protein levels are even more affected by C. diplogaster than by Parasitaphelenchus, while incorporation into ovaries seems to be less affected in spite of slower ovarian growth. C. diplogaster might thus essentially act both upon proteins which are not required for the ovarian maturation of their host and upon nonproteinaceous substances that are required for such maturation. Results are discussed in relation to the possible mode of action of parasitic nematodes.     

Distribution and changes of serotonin and dopamine levels in the central nervous system and ovary of the Pacific white shrimp, <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>, during ovarian maturation cycle

We investigated changes in serotonin (5-HT) and dopamine (DA) levels and in their distribution patterns in the central nervous system (CNS) and ovary during the ovarian maturation cycle in the Pacific white shrimp, Litopenaeus vannamei. The concentrations of these two neurotransmitters were determined by using high performance liquid chromatography with electrochemical detection. The 5-HT concentration exhibited a gradual increase in the brain and thoracic ganglia during early ovarian stages I, II, and III, reaching a maximum at the mature ovarian stage IV, whereas DA showed its highest concentration at ovarian stage II in the brain and thoracic ganglia and then declined to its lowest concentration at ovarian stage IV. In the ovaries, 5-HT was lowest at ovarian stage I and gradually increased to a peak at ovarian stage IV. Conversely, the concentration of DA was highest at ovarian stages I and II and lowest at ovarian stage IV. In the brain, 5-HT immunoreactivity (−ir) from stage IV and DA-ir from stage II were distributed extensively in neurons of clusters 6, 11, and 17, in fibers, and in the anterior and posterior medial protocerebral, olfactory, antenna II, and tegumentary neuropils. In the circumesophageal, subesophageal, thoracic, and abdominal ganglia, both 5-HT-ir and DA-ir were detected in neuropils and surrounding neurons and fibers. 5-HT-ir and DA-ir were more intense in the thoracic ganglia than in other parts of the CNS. In the ovary, 5-HT-ir exhibited high intensity in late oocytes, whereas DA-ir was more intense in early oocytes. Thus, opposing changes occur in the levels of these two neurotransmitters and in their specific localizations in the CNS and ovary during ovarian maturation, indicating their important involvement in female reproduction.     

Sexual dimorphism in desiccation responses of the sand scorpion Smeringurus mesaensis (Vaejovidae)

The osmoregulatory and respiratory responses of male and female Smeringurus mesaensis (Vaejovidae) to prolonged desiccation were measured. No significant effect of sex on mass-loss rates (MLRs) was found. Still, females maintained their haemolymph osmolality when desiccated to 10% mass loss, whereas that of males increased significantly after loss of as little as 5% of initial mass. Females had a 3-fold larger hepatopancreas, significantly higher hepatopancreas water content and higher metabolic rates when adjusted to hepatopancreas-free dry mass. Thus, females not only store more water in the hepatopancreas but also mobilise it to the haemolymph at a higher rate during desiccation, thus maintaining haemolymph osmolality. Gas exchange rates of both males and females decrease as desiccation progresses. An initial respiratory exchange ratio (RER) of approximately 0.9 is followed by a significant increase at mass loss levels of 7.5% and higher. RER values greater than 1.0 may result from partial shift to anaerobic catabolism, which allows closure of the book lung spiracles for longer duration, thus minimising respiratory water loss. The effects of gas exchange rates on rates of water mobilisation between body compartments and water loss to the environment suggest a trade-off between maintaining osmotic stability and conserving body water stores under stressful conditions.     

Variations de la composition lipidique tissulaire au cours de la vitellogenese chez la crevette Penaeus indicus Milne Edwards

Changes in lipid composition are observed in the ovary, the hepatopancreas, the haemolymph and the muscle of the female Penaeus indicus Milne Edwards, during the increase of the gonad-somatic index (GSI). Vitellogenesis is characterized by a large accumulation of lipids in the ovary, which seems to be practically linear when expressed as a function of GSI, if there is no interference from moulting. Phospholipids and triacylglycerols are the major lipid fractions in the ovary, but some classes of minor importance, like wax esters, hydrocarbons, and glyceryl ethers, are also incorporated. These last components may play a rôle in the maturation process.The lipid reserves of the hepatopancreas contribute partially to the formation of vitellin, but direct input of lipids from feeding seems to be preponderant. An intraovarian synthesis of lipids may be possible, but probably restricted, considering the low concentrations of free fatty acids and partial acylglycerols found in the ovary. Phospholipids are the main components involved in the increase in lipid concentration of the haemolymph during vitellogenesis. This increase, and the potential rise in the turnover of circulating lipids, suggest a deep alteration in the lipid metabolism of the females during the breeding period.     

Gamma-aminobutyric acid in the genital tract of the rat during the oestrous cycle

The highest values of gamma-aminobutyric acid (GABA) in the genital tract of the rat at different stages of the oestrous cycle were found in the oviduct (3.5-7 micrograms/mg protein) and the lowest in the ovary (50-100 ng/mg protein). The values for uterus and vagina ranged between 80 and 150 ng/mg protein. GABA (10-30 ng/microliter) was also found in fluid in the ovarian bursa. At 11:00 h, on the day of oestrus, GABA content increased in the ovaries but values in the oviducts were maximal at 11:00 h on the day of pro-oestrus. Variations in GABA content of the vagina were also found. Uterine cervix or uterine horn showed no changes during the oestrous cycle. The GABA content was not uniform throughout the oviduct: the highest values were found in the portion next to the ovary. At 10 days after removal of the right oviduct, GABA values in the ovary and ovarian bursa fluid decreased on the operated side. At 1 month after surgery, the values in ovary were normal but the values in ovarian bursa fluid were still low, suggesting that the source of ovarian GABA was not the oviduct. The variations observed in the present paper suggest an involvement of GABA in reproductive physiology.     

Structure,haemolymph titre,and regulatory effects of juvenile homone during ovarian maturation in Leucophaea maderae

Juvenile hormone (JH) synthesized and secreted in vitro by the corpora allata of mated adult Leucophaea maderae females was determined to be JH III (methyl-10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate).The haemolymph titre of JH was determined during maturation of the terminal oöcytes in the first reproductive cycle of L. maderae. In virgin females, JH is not detectable in the haemolymph during the first eight days following adult emergence; however, by 10 days after emergence, trace quantities of JH are apparent. Mating stimuli induce a dramatic increase in the concentration of haemolymph JH, with a peak occurring approximately 12 days after mating; thereafter, the JH concentration declines until it has reached an undetectable level 19 days after mating, at the time of chorion deposition.During ovarian maturation, changes in the rates of synthesis of vitellogenin by the fat body and DNA by the ovary correlate closely with the haemolymph titre of JH. However, no such correlation exists between the JH titre and the extensive ovarian protein synthesis that occurs in L. maderae coincident with chorion formation.The effects of JH I and JH III on both vitellogenin synthesis and ovarain DNA synthesis are statistically similar.     

长江刀鲚生殖洄游期间脂肪酸组成及含量变化分析

为探究长江刀鲚生殖洄游过程中脂肪酸组成及其含量变化规律,研究选择洄游距离、卵巢发育和规格大小3个影响因子设置梯度,对长江刀鲚肝胰腺、肌肉和卵巢的脂肪酸组成及含量进行实验分析。实验结果显示, 62尾雌性刀鲚3个组织均检测出28种脂肪酸,以单不饱和脂肪酸(MUFA)含量最高,大于各组织总脂肪酸含量的56.23%,各类脂肪酸中的C18:1、C16:0、C16:1、DHA和EPA含量较高,为主要脂肪酸。在生殖洄游过程中,刀鲚肝胰腺总脂肪含量随洄游距离的延长呈上升趋势,从崇明江段的(526.61±38.50) mg/g增加至安庆江段的(587.21±124.72) mg/g,而肌肉和卵巢总脂肪酸含量呈显著下降趋势,分别下降了33.03%和57.09%(P<0.05)。在各体长组中,肌肉总脂肪酸、SFA、MUFA和PUFA含量与体长呈正相关(P<0.05),而肝胰腺和卵巢总脂肪酸及各类脂肪酸含量与体长无显著相关性(P>0.05)。在卵巢发育过程中,刀鲚肝胰腺和肌肉总脂肪酸、MUFA和PUFA含量随卵巢由Ⅱ期发育至Ⅳ期均呈下降趋势,总脂肪酸含量分别减少了47.56%和22.40%,...     

The chemosensitivity of labellar sugar receptor in female Phormia regina is paralleled with ovary maturation: Effects of serotonin

Oogenesis in most adult insects is a nutrient-dependent process involving ingestion of both proteins and carbohydrates that ultimately depends on peripheral input from chemoreceptors.The main goal of this study was to characterize, in the female blowfly Phormia regina, the responsive changes of the labellar chemoreceptors to carbohydrates and proteins in relation to four different stages along the ovarian cycle: (1) immature ovaries, (2) mid-mature ovaries, (3) mature ovaries and ready for egg-laying and (4) post egg-laying ovaries. Then, the possible effects exerted by exogenous serotonin on the chemoreceptor sensitivity profiles were investigated.Our results show that ovary length, width and contraction rate progressively increase from stage 1 to 3, when all these parameters reach their maximum values, before declining in the next stage 4.The sensitivity of the labellar “sugar” chemoreceptors to both sucrose and proteins varies during the ovarian maturation stages, reaching a minimum for sucrose in stage 3, while that to proteins begins. Exogenous 5-HT supply specifically increases the chemoreceptor sensitivity to sugar at the stages 3 and 4, while it does not affect that to proteins.In conclusion, our results provide evidence that in female blowflies the cyclic variations in the sensitivity of the labellar chemosensilla to sugars and proteins are time-related to ovarian development and that during the stages 3 and 4 the responsiveness of the sugar cell to sucrose is under serotonergic control.     

MnHSP90 cDNA characterization and its expression during the ovary development in oriental river prawn, <Emphasis Type="Italic">Macrobrachium nipponense</Emphasis>

Heat shock protein 90 (HSP90) is not only involved in environmental stress but also plays roles in the ovary development in some vertebrates. To understand its role in crustacean, we examined the HSP90 cDNA for the first time in the ovary and hepatopancreas of the oriental river prawn, Macrobrachium nipponense and designated this protein as MnHSP90 in this study. The MnHSP90 was cloned by the methods of degenerated oligonucleotide primers and rapid amplification of the cDNA ends (RACE). Bioinformatics analysis showed that the MnHSP90 cDNA was 2,684 bp in length, containing a 126 bp 5′ untranslated region (UTR), a 359 bp 3′ UTR, and an open reading frame (ORF) of 2,199 bp encoding a 732-amino acid polypeptide with predicted molecular mass of 84.3 KDa. Sequence alignment showed that the MnHSP90 shared 72–79% identity with other animals. Real-time quantitative PCR (qPCR) analysis demonstrated that the MnHSP90 mRNA was ubiquitously detected in all tested tissues, with the highest expression in the thoracic ganglia, the mediate in heart, muscle and intestine, and the lowest in haemocytes and gills. The MnHSP90 mRNA levels in the hepatopancreas and ovary of M. nipponense reached a maximum at the stage III (early vitellogenic stage) and stage IV (later vitellogenic stage) ovaries, respectively, and then decreased significantly in both tissues as the ovarian development proceeded. The level of MnHSP90 expression in the hepatopancreas was higher than that in the ovary when compared with in the same ovarian developmental stage. Our results indicate that MnHSP90 is involved in ovarian development in oriental river prawn and may play a regulatory role in ovary maturation.