Changes in progesterone levels and distribution of progesterone receptor during vitellogenesis in the female mud crab (Scylla paramamosain)

Vertebrate-type steroids, such as progesterone, have been identified in crustaceans. The physiological activity of progesterone during vitellogenesis is still not well understood. In this study, progesterone levels in the female mud crab, Scylla paramamosain, were determined by enzyme-linked immunosorbent assay. Peak levels of progesterone were detected during the previtellogenic stage in the hemolymph, ovary, and hepatopancreas, whereas the progesterone level decreased significantly in vitellogenic stage I. During vitellogenic stage II, progesterone levels rose again in the hemolymph and ovary, but continued to decrease in the hepatopancreas. By using western blotting, progesterone receptor (PR), with an apparent molecular weight of 70 kDa, was identified in the ovary during both vitellogenic stages I and II. By means of immunohistochemistry, PR was detected mainly in the follicle cells during vitellogenic stage I and in the nuclei of oocytes in vitellogenic stage II. Our results strongly suggest that progesterone promotes vitellogenesis in the mud crab, S. paramamosain via a classical genomic mechanism.     

Maturation-related variations in prostaglandin and fatty acid content of ovary in the kuruma prawn (Marsupenaeus japonicus)

Total lipid, fatty acids and prostaglandins (PGF(2 alpha) and PGE(2)) in the ovary of kuruma prawns (Marsupenaeus japonicus) were measured during ovarian development. The level of ovarian total lipid increased with an increase in the gonad-somatic index (GSI). No significant difference was found in fatty acid composition among different stages of ovarian development. However, the content of arachidonic acid (precursor of PG(2)), but not eicosapentanoic acid (precursor of PG(3)), was significantly lower at stages I and II than at stage V (P<0.01). When ovarian PGF(2 alpha) and PGE(2) levels were plotted against GSI, no correlation was found in either PG. However, in terms of ovarian developmental stages, the level of ovarian PGs was high (approx. 20 pg/mg) at stage I, followed by marked decreases at stages IV and V (PGF(2 alpha), P<0.01) and stage IV (PGE(2), P<0.01). These results suggest that ovarian PGs and arachidonic acid are deeply involved in ovarian maturation in kuruma prawns.     

Catabolite repression of the colonization factor antigen I (CFA/I) operon ofEscherichia coli

Experiments were performed to study whether the synthesis of the fimbrial colonization factor antigen I (CFA/I) of enterotoxigenicEscherichia coli is affected by glucose. The CFA/I-producing strain H-10407 (O78:H11:CFA/I) was grown in CFA medium containing various concentrations of glucose. Addition of 1% glucose into the medium resulted in a pronounced decrease in CFA/I production by H-10407 as assessed by ELISA, hemagglutination, and electron microscopy. The repressive effect of glucose was reversed by the addition of 10 mM cAMP to the medium. Examination of the promoter sequence of thecfaA gene of the CFA/I operon revealed a consensus binding site for the catabolite activator protein-cAMP complex. With a reporter plasmid containing a fusion of thecfaA promoter, a portion of thecfaA gene, and thelacZ gene, it was shown that the activity of this promoter was influenced by glucose. In a wild-typeE. coli strain, addition of 0.5% glucose to the growth medium diminished the promoter activity more than 70%. ThecfaA promoter also exhibited a lower level of activity incya (adenyl cyclase) andcrp (cAMP receptor protein) mutants than in the wild-type strain. The addition of 10 mM cAMP resulted in a marked increase in the expression from thecfaA promoter in thecya but not in thecrp mutant. These results suggest that the suppressive effect of glucose in the CFA/I system is mediated via the mechanism of catabolite repression through thecfaA promoter of the CFA/I operon.     

Ovarian maturation and oogenesis in the blue swimmer crab,Portunus pelagicus (Decapoda: Portunidae)

The study was aimed at understanding the process of reproduction and the changes happening in the ovary of Portunus pelagicus during maturation, which would be useful for its broodstock development for hatchery purposes. For that, tissue samples from different regions of the ovary at various stages of maturation were subjected to light and electron microscopy, and based on the changes revealed and the differences in ovarian morphology, the ovary was divided into five stages such as immature (previtellogenic oocytes), early maturing (early vitellogenic oocytes), late maturing (late vitellogenic oocytes), mature (vitellogenic oocytes), and spent (resorbing oocytes). The ovarian wall comprised of an outermost thin pavement epithelium, a middle layer of connective tissue, and an innermost layer of germinal epithelium. The oocytes matured as they moved from the centrally placed germinal zone toward the ovarian wall. The peripheral arrangement of nucleolar materials and the high incidence of cell organelles during the initial stages indicated vitellogenesis I. Movement of follicle cells toward oocytes in the early maturing stage and low incidence of mitochondria and endoplasmic reticulum in the ooplasm during late vitellogenic stage marked the commencement and end of vitellogenesis II, respectively. Yolk granules at various stages of development were seen in the ooplasm from late vitellogenic stage onwards. The spent ovary had an area with resorbing oocytes and empty follicle cells denoting the end of one reproductive cycle and another area with oogonial cells and previtellogenic oocytes indicating the beginning of the next.     

Natural sex change in mature protogynous orange-spotted grouper (Epinephelus coioides): gonadal restructuring,sex hormone shifts and gene profiles

Sexual patterns of teleosts are extremely diverse and include both gonochorism and hermaphroditism. As a protogynous hermaphroditic fish, all orange-spotted groupers (Epinephelus coioides) develop directly into females, and some individuals change sex to become functional males later in life. This study investigated gonadal restructuring, shifts in sex hormone levels and gene profiles of cultured mature female groupers during the first (main) breeding season of 2019 in Huizhou, China (22° 42′ 02.6″ N, 114° 32′ 10.1″ E). Analysis of gonadal restructuring revealed that females with pre-vitellogenic ovaries underwent vitellogenesis, spawning and regression and then returned to the pre-vitellogenic stage in the late breeding season, at which point some changed sex to become males via the intersex gonad stage. A significant decrease in the level of serum 17β-estradiol (E2) was observed during ovary regression but not during sex change, whereas serum 11-ketotestosterone (11-KT) concentrations increased significantly during sex change with the highest concentration in newly developed males. Consistent with serum hormone changes, a significant decrease in cyp19a1a expression was observed during ovary regression but not during sex change, whereas the expression of cyp11c1 and hsd11b2 increased significantly during sex change. Interestingly, hsd11b2 but not cyp11c1 was significantly upregulated from the pre-vitellogenic ovary stage to the early intersex gonad stage. These results suggest that a decrease in serum E2 concentration and downregulation of cyp19a1a expression are not necessary to trigger the female-to-male transformation, whereas increased 11-KT concentration and upregulation of hsd11b2 expression may be key events for the initiation of sex change in the orange-spotted grouper.     

Viviparity in the halfbeak genera Dermogenys and Nomorhamphus (Teleostei: Hemiramphidae)

Gravid ovaries were examined histologically from two species of Nomorhamphus and 21 populations of Dermogenys. In addition, changes in dry-weight throughout gestation are provided for 15 populations. The ovaries are paired organs running along the lateral body wall and are separated along most of their length. In all specimens examined, embryos are fertilized within the ovarian follicle. Viviparity in these species is divided herein into five categories designated types I–V. In types I and II the entire gestation period is intrafollicular, whereas in types III–V only the early stages of gestation are intrafollicular with the major period of development occurring in the ovarian lumen (intraluminal). Type I is characterized by the retention of a large amount of yolk throughout gestation. Superfetation is not observed. Populations of D. pusilla from Vietnam and Thailand decrease in dry-weight throughout gestation. This, coupled with the slight vascularization of the yolk sac, suggests strict lecithotrophy. Populations of D. pusilla from Singapore and Bangladesh undergo an increase in dry weight and exhibit an increased vascularization of the yolk sac, suggesting a form of unspecialized matrotrophy. Type II is characterized by a small amount of yolk, an expansion of the coelomic cavity and pericardial sac, and a simple cuboidal epithelium on the general body surfaces. Superfetation occurs with up to three broods present within a single ovary. Dermogenys pusilla from Sabah, D. orientalis and Dermogenys sp. (Sulawesi) exhibit the type II form of viviparity. Dermogenys vivipara from the eastern Philippine islands of Culion and Busuanga exhibit characteristics considered intermediate between type I and II. These results are compared with those from other viviparous species exhibiting intrafollicular gestation. In species with types III–V (intraluminal gestation), developing oocytes are restricted to a distinct ridge of ovigerous tissue extending along the entire length of the ovary. Two species, D. viviparus (Luzon, Philippines) and Dermogenys sp. (Luzon) have the type III form of viviparity. In this form, oocytes are small (0.8–1.0 mm) with little yolk reserves and embryos, covered with a simple cuboidal epithelium and possessing an expanded belly sac, are retained within the follicles until a late fin-bud stage. Type III embryos found within the ovarian lumen have a greatly expanded belly sac and remain covered by a simple cuboidal epithelium until parturition. Superfetation is present in these species with two broods observed simultaneously within a single ovary. Five species, D. megarrhamphus, D. weberi, D. viviparus (Jolo, Philippines), Nomorhamphus sp. (Sulawesi), and N. towoetii, were observed with the type IV form of viviparity. Embryos in this category are evacuated into the ovarian lumen prior to a fin-bud stage and retain a large yolk mass throughout development. Superfetation is absent in these species. A differentform of viviparity (type V) is present in D. ebrardtii in which embryos appear to obtain nutrients through a form of oophagy and aldelphophagy (feeding on developing oocytes or less-developed siblings). In all specimens with intraluminal development, atretic oocytes within the ovigerous ridge are abundant. These findings support the hypothesis that current species and generic limits may be artificial and underscores the potential of histological evidence for phylogenetic analysis of this group. J. Morphol. 234:295–317, 1997. © 1997 Wiley-Liss, Inc.     

The effect of gonadotropin on glucose transport and apoptosis in rat ovary

Although the effects of Gonadotropin on ovarian physiology have been known for many decades, its action on glucose uptake in the rat ovary remained poorly understood. Evidence also suggests that glucose uptake is mediated by a number of glucose transporter proteins (Glut). Therefore, we examined the rat ovary for the presence of Glut1-4 and blood glucose level after eCG (equine chorionic gonadotropin) and anti-eCG antiserum treatment. All of the glucose transports were present in the ovarian oocyte, granulosa cells and theca cells in different stage follicles. The expression of Glut in ovary was up-regulated by eCG, however, anti-eCG antiserum reversed eCG action. Western blot analysis also demonstrated the content of Glut1 was higher in eCG treatment group compared with anti-eCG antiserum and control group. The same tendency was shown in other glut isoforms. Moreover, there were no significant difference between the anti-eCG antiserum and control group. In additional, the level of serum glucose in eCG treatment group was significantly higher than others, which is similar with glut expression pattern. High glucose level in blood is correlated with increased expression of glucose transporter proteins in rat ovary. Meanwhile, anti-eCG antiserum increased granulosa cell apoptosis in antral follicle compared with those in eCG group. Our observations provide potential explanation for the effects of Glut on follicular development in rat ovary and a role for eCG in the regulation of ovarian glucose uptake.     

Blood glucose in marine penaeid prawns: I. Neuroendocrine regulation in Parapenaeopsis hardwickii (Miers). (Crustacea,Decapoda, Penaeidae)

In the present investigation on femaleP. hardwickii, the blood glucose level in bilateral eyestalk extirpated, reinjected with ES extract as well as normal prawns, administered with ES, different concentrations of BR and ThG extracts, was estimated quantitatively after fifteen minutes and two hours. During all treatments there was an immediate hike in blood glucose level after fifteen minutes but after 24 hr. of eyestalk ablation the level does not differ significantly (P > 0.05) from controls. There was a significant (P < 0.01) enhancement in blood glucose level in the cauterized eyestalkless and normal prawns injected with ES extract after 2 hr. There was a considerable (93% level of confidence) decrease in blood glucose level of normal prawns after injecting higher concentrations of BR and ThG extracts. There was an obvious change in blood glucose level due to the endocrine hormones injected from other prawns of the related family. ES extracts ofP. stylifera produced a significant (P < 0.01) increase, whereas higher concentration of BR and ThG extracts caused considerable (92% level of confidence) decrease in blood glucose level after injecting in cauterized eyestalkless prawns. The extracts of the same endocrine centres fromMetapenaeus monocerus did not induce any significant (P > 0.05) alteration in blood glucose quantity ofP. hardwickii. Hence from the above findings it may be inferred that, the hormones produced by eyestalks (X organ-Sinus gland Complex) posses a hyperglycemic factor, whereas hormones released from BR and ThG might be having a property to cause hypoglycemia (?).     

Immunological analysis of lipophorin in the haemolymph,ovaries, and testes of the fall webworm,Hyphantria cunea (Drury)

Lipophorin (LP) was purified from haemolymph in last instar larvae of Hyphantria cunea (Drury) by KBr density gradient ultracentrifugation and gel filtration. LP is composed of Apo-LP I and Apo-LP II with molecular weights of 230 kDa and 80 kDa, respectively. The level of haemolymph LP in early pupae was somewhat greater than in last instar larvae. In males, this LP concentration is maintained throughout pupal development, whereas the level of haemolymph LP decreases in female pupae beginning at day 7, coincident with the onset of vitellogenesis in the fall webworm. In both male and female adults, haemolymph LP concentrations were dramatically increased in comparison to their pre-adult levels. Actually, LP was found in the ovary by immunodiffusion, tandem-crossed immunoelectrophoresis, and Western blotting. Location of LP in the ovary was also traced by immunogold labelling. Also, LP appeared in small amounts in protein yolk bodies of the ovary at an early stage of vitellogenesis, when nurse cells are bigger than the oocyte, but in greater amounts at those stages when the oocyte is larger than nurse cells—that is, when vitellogenesis is actively taking place. This fact clearly reveals that LP is synthesized by fat body and released into the haemolymph, and then taken up by the growing ovary during vitellogenesis. Also, LP was detected in testes by immunological analysis. Western blotting showed that LP was present in testicular fluid but not in the peritoneal sheath and cysts. To test whether LP is also synthesized in testes, testes and fat body tissues were cultured in vitro, indicating that fat body synthsizes LP but testes do not. The result showed that the haemolymph LP itself is taken up into the testes. © 1994 Wiley-Liss, Inc.     

A <Emphasis Type="Italic">vasa</Emphasis> gene from green mud crab <Emphasis Type="Italic">Scylla</Emphasis><Emphasis Type="Italic">paramamosain</Emphasis> and its expression during gonadal development and gametogenesis

VASA is one of the important regulatory factors that determine the development of the reproductive system. However, no information on vasa gene from Pleocyemata Brachyura is available. By using Race, we obtained a full-length cDNA of Sp-vasa of the green mud crab Scylla paramamosain. The full-length (2,851 bp) cDNA of vasa encodes a peptide of 631 amino acids. Real-time PCR results indicated that the expression level of Sp-vasa in the growth stage of ovary was higher than in the maturation stage, and in stage I and II of testis, the expression level of Sp-vasa were higher than in stage III. By using in situ hybridization, Sp-vasa RNAs were detected in the large part of oocyte plasm in stage I, nucleus zone in stage III and perinuclear zone in stage V. As the size of oocytes increases during oogenesis, the signals change from strong to weak. In addition, in stage I and II of testis, the expression levels of Sp-vasa were higher than in stage III, and the hybridization intensity of Sp-vasa gene gradually increased during spermatogenesis from spermatogonia to spermatids. However, no hybridization signal was detected in spermatozoon. Real-time PCR and in situ hybridization were consistent. These findings suggest that Sp-vasa is likely to serve as a useful and specific marker for germ cell development of S. paramamosain.     

Ovarian structure,folliculogenesis and oogenesis of the annual killifish Millerichthys robustus (Cyprinodontiformes: Cynolebiidae)

Cellular aspects of oocyte development of the Mexican rivulus Millerichthys robustus were morphologically described in order to analyze ovarian function and the cellular recruitment dynamics associating it with life history strategies of annual killifishes. Millerichthys is an iteroparous batch spawner with continuous oocyte recruitment and indeterminate fecundity with asynchronous development of the follicles. It has two ovaries of cystovarian type, with a central lumen, which communicates with the outside through the caudal region of the ovary, that is, the gonoduct. From the walls of the ovary, irregular lamellae composed of germinal epithelium and vascularized stroma project. Oogenesis starts with oogonial proliferation, found alone or in nests within the germinal epithelium. The oogonia come into meiosis becoming oocytes and advancing to the chromatin nucleolus stage and to early primary growth stage. Folliculogenesis is completed in the primary growth stage and cortical alveoli step. Follicles moves toward the stroma, but they continue to be attached to the germinal epithelium through the basement membrane until ovulation. The inclusion of fluid yolk in the follicles during the secondary growth stage was observed. During ovulation, the follicle collapsed, the oocyte was released into the lumen, and the constitutive elements of the post-ovulatory follicle complex remained in the stroma.     

Pollen-pistil interactions in Hermodactylus tuberosus Mill. (Iridaceae)

ABSTRACT

Hermodactylus tuberosus Mill. (Iridaceae) is a species with a very short style and a tricarpellar unilocular ovary. For ornamental purposes it is usually reproduced by means of tubers, although both vegetative and seed reproduction occur in nature. However, its capsules do not contain many seeds in comparison to the high number of ovules inside the ovary. To understand this conflicting process a study on H. tuberosus pollen-pistil interaction was carried out. Pollen viability was evaluated by different techniques. Germination rate was tested in vitro and in vivo after stigma, intrastylar and intraovarian pollinations. A high percentage of the pollen grains were found to be viable resulting in a high percentage of in vitro germination and a low rate of germination on the stigma. Indeed, many pollen tubes developed after intrastylar and intraovarian pollinations. Several anomalies characterized pollen germination and pollen tube growth in vitro and in vivo. Observations from field trials indicated that capsules were only produced from open or hand, cross- pollinated flowers, confirming that the plant is self- incompatible and not apomictic. In addition, all the mature capsules contained only a few mature seeds suggesting the existence of pre- and postzygotic seed set inhibition.     

Growth and biochemical responses of jojoba (Simmondsia chinensis (Link) Schneid) explants cultured under mannitol-simulated drought stress in vitro

Jojoba explants were cultured under four levels of mannitol (control plus 50, 100, 250 and 500 mM mannitol)-induced osmotic stress during the proliferation stage in vitro. Explants grown under control condition exhibited the highest growth, while the more severe the stress was, the lower was the growth of explants. Electrolyte leakage, lipid peroxidation, H₂O₂ content and proline concentration were highest and relative water content lowest under the highest level of osmotic stress. Concentration of phenolic compounds (total phenolic compounds, o-diphenols and flavanols, as well as protocatechuic, vanillic, p-coumaric and ferulic acids and rutin), putrescine and total polyamines decreased with increasing stress level. Mannitol, glucose and pinitol concentrations increased, whereas that of inositol decreased with increasing stress level. Explants were transferred to the rooting stage, separately per stress treatment. Explants grown under stress conditions during the proliferation stage exhibited lower rooting percentage than controls, as the stress became more severe, the lower was the rooting response. Jojoba tolerated osmotic stress to some extent (till 100–250 mM mannitol), exhibiting sufficient growth rate and good rooting response as well as low oxidative damage (based on electrolyte leakage and lipid peroxidation indices).     

Morphological characterization of the ovary and oocytes vitellogenesis of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae)

This study presents the morphology of the ovary, as well as the process of the vitellogenesis in oocytes of the tick Rhipicephalus sanguineus. The ovary of these individuals is of the panoistic type; therefore, it lacks nurse cells. This organ consists of a single tubular structure, continuous, and composed of a wall formed by small epithelial cells with rounded nuclei which delimit the lumen. The oocytes in the different developmental stages in this tick species were classified into five stages (I-V). They remain attached to the ovary during vitellogenesis by a cellular pedicel and afterwards the mature oocytes (stage V) are released into the ovary lumen.     

The stage of ovarian development affects organ expression of vitellogenin as well as the morphometry and ultrastructure of germ cells in the freshwater prawn Macrobrachium amazonicum (Heller, 1862)

The objective was to characterize vitellogenin expression in the ovary and hepatopancreas, and to describe the morphometry and ultrastructure of oocytes, in the freshwater prawn Macrobrachium amazonicum at various stages of ovarian development. Five ovarian stages were defined: (I) immature, (II) maturing, (III) mature, (IV) spawned, and (V) reorganized. Ovaries and hepatopancreas were analyzed by immunohistochemistry for vitellogenin expression. Vitellogenin expression in both ovary and hepatopancreas was predominantly widespread, beginning at Stage I, peaking at Stage III, and decreasing in Stages IV and V. Characterization of the ovary included measurement of the following germ cell types: oogonia (OG), and previtellogenic (PV), early vitellogenesis (EV), advanced vitellogenesis (AV), and mature (M) oocytes. Mean ± SD diameter of OG and EV oocytes in Stages I (14.2 ± 5.5 and 119.8 ± 15.7 μm) and II (17.9 ± 4.8 and 114.3 ± 34.6 μm), respectively, were significantly different from that in Stages IV (16.6 ± 4.7 and 107.0 ± 24.6 μm) and V (14.4 ± 4.1 and 101.0 ± 25.2 μm). Both scanning and transmission electron microscopy enabled identification of EV, AV and M oocytes based on the presence of a nucleus, and the organization and distribution of yolk in the cytoplasm. In summary, vitellogenesis occurred both in the hepatopancreas and ovary, with the ovary expressing vitellogenin starting as early as Stage I. This process promoted accumulation of yolk and growth of oocytes, thus favoring sexual maturation of females. This knowledge may be applied to improve production of farmed M. amazonicum.     

Variation of (1 leads to 3)-beta-glucanases in Saccharomyces cerevisiae during vegetative growth, conjugation, and sporulation.

The total (1 leads to 3)-beta-glucanase activities associated with cell extracts and cell walls of Saccharomyces cerevisiae were measured during vegetative growth, conjugation, and sporulation. Using a system of column chromatography, we resolved (1 leads to 3)-beta-glucanase activity into six different enzymes (namely, glucanases I, II, IIIA, IIIB, IV, and V). The contributions of the individual enzymes to the total activity at the different stages of the life cycle were determined. Total glucanase activity increased during exponential growth and decreased in stationary resting-phase cells. Glucanase IIIA was the predominant enzyme in stationary resting-phase cells. Glucanases I, II, IIIB, and IV were either absent or present at low levels in stationary phase cells, but their individual activities (in particular, glucanase IIIB activity) increased substantially during exponential growth. Total (1 leads to 3)-beta-glucanase activity did not change significantly during conjugation of two haploid mating strains, S. cerevisiae 2180A and 2180B, and no notable changes were detected in the activities of the individual enzymes. Sporulation was accompanied by a rapid increase and then a decrease in total glucanase activity. Most of the increase was due to a dramatic rise in the activity of glucanase V, which appeared to be a sporulation-specific enzyme. Glucanase activity was not derepressed by lowering the glucose concentration in the growth medium.     

Dendrocalamus parvigemma sp. nov. (Gramineae: Bambusoideae) from Vietnam

A new species of Dendrocalamus Nees from Vietnam, D. parvigemma N. H. Xia, V. T. Nguyen et V. L. Le, is described and illustrated. The new species is morphologically similar to D. latiflorus Munro and D. yunnanicus Hsueh & Li, from which it differs by having a very small and nearly circular culm bud, dense, 1.4–1.6 cm long, palea with bristles and apex split in 2, narrowly lanceolate ovary, and sheath ligule 5 mm heigh and irregularly serrulate.