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1.
Crustacean hyperglycemic hormone (CHH), molt-inhibiting hormone (MIH), and gonad-inhibiting hormone (GIH) are members of a major peptide family produced from the X-organ sinus gland complex in the eyestalk of crustaceans. This peptide family plays important roles in controlling several physiologic processes such as regulation of growth and reproduction. In this study the complementary DNA encoding a peptide related to the CHH/MIH/GIH family (so-called Pem-CMG) of the black tiger prawn Penaeus monodon was successfully expressed in the yeast Pichia pastoris under the control of the AOX1 promoter. The recombinant Pem-CMG was secreted into the culture medium using the -factor signal sequence; of Saccharomyces cerevisiae without the Glu-Ala-Glu-Ala spacer peptide. The amino terminus of the recombinant Pem-CMG was correctly processed as evidenced by amino-terminal peptide sequencing. The recombinant Pem-CMG was purified by reverse-phase high-performance liquid chromotography and used in a biological assay for CHH activity. The final yield of the recombinant Pem-CMG after purification was 260 µg/L of the culture medium. Both crude and purified recombinant Pem-CMG produced from P. pastoris showed the ability to elevate the glucose level in the hemolymph of eyestalk-ablated P. monodon, which demonstrates that Pem-CMG peptide functions as hyperglycemic hormone in P. monodon.  相似文献   

2.
Proteomics and signal transduction in the crustacean molting gland   总被引:1,自引:0,他引:1  
Regulation of the molting cycle in decapod crustaceans involves2 endocrine organs: the X-organ/sinus gland (XO/SG) complexlocated in the eyestalk ganglia and the Y-organ (YO) locatedin the cephalothorax. Two neuropeptides [molt-inhibiting hormone(MIH) and crustacean hyperglycemic hormone (CHH)] are producedin the XO/SG complex and inhibit ecdysteroidogenesis in theYO. Thus, YO activation is induced by eyestalk ablation (ESA),which removes the primary source of MIH and CHH. Cyclic nucleotides(cAMP and cGMP) and nitric oxide (NO) appear to mediate neuropeptidesuppression of the YO. Proteomics was used to identify potentialcomponents of signal transduction pathways ("targeted" or cell-mapproteomics) as well as assess the magnitude of protein changesin response to activation ("global" or expression proteomics)in the tropical land crab, Gecarcinus lateralis. Total proteinsin YOs from intact and ES-ablated animals were separated bytwo-dimensional gel electrophoresis and expression profileswere assessed by image analysis and gene clustering software.ESA caused a >3-fold increase in the levels of 170 proteinsand >3-fold decrease in the levels of 89 proteins; a totalof 543 proteins were quantified in total YO extracts. ESA inducedsignificant changes in the levels of 3 groups of proteins elutingfrom a phosphoprotein column and detected with phosphoproteinstaining of two-dimensional gels;  相似文献   

3.
The profiles of circulating ecdysteroids during the three molt cycles prior to adulthood were monitored from the juvenile blue crab, Callinectes sapidus. Ecdysteroid patterns are remarkably similar in terms of peak concentrations ranging between 210–330 ng/ml hemolymph. Analysis of hemolymph at late premolt stage revealed six different types of ecdysteroids with ponasterone A (PoA) and 20‐OH ecdysone (20‐OH E) as the major forms. This ecdysteroid profile was consistent in all three molt cycles. Bilateral eyestalk ablation (EA) is a procedure that removes inhibitory neurohormones including crustacean hyperglycemic hormone (CHH) and molt‐inhibiting hormone (MIH) and often results in precocious molting in crustaceans. However, the inhibitory roles of these neuropeptides in vivo have not yet been tested in C. sapidus. We determined the regulatory roles of CHH and MIH in the circulating ecdysteroid from ablated animals through daily injection. A daily administration of purified native CHH and MIH at physiological concentration maintained intermolt levels of ecdysteroids in the EA animals. This suggests that Y organs (YO) require a brief exposure to CHH and MIH in order to maintain the low level of ecdysteroids. Compared to intact animals, the EA crabs did not exhibit the level of peak ecdysteroids, and the major ecdysteroid turned out to be 20‐OH E, not PoA. These results further underscore the important actions of MIH and CHH in ecdysteroidogenesis, as they not only inhibit, but also control the composition of output of the YO activity. © 2009 Wiley Periodicals, Inc.  相似文献   

4.
Molting processes in crustaceans are regulated by ecdysteroids produced in the molting gland (Y-organ), and molting is indirectly controlled by circulating factors that inhibit the production of these polyhydroxylated steroids. Two of these regulatory factors are the neuropeptides molt-inhibiting hormone (MIH) and crustacean hyperglycemic hormone (CHH). CHH appears to inhibit ecdysteroidogenesis in the Y-organ through the activation of a receptor guanylyl cyclase. The signaling pathway activated by MIH, however, remains a subject of controversy. It is clear that neuropeptides inhibit ecdysteroidogenesis by simultaneously suppressing ecdysteroid biosynthetic processes, protein synthesis, and uptake of high density lipoproteins. Data demonstrate that cAMP is the primary regulator of critical catabolic, anabolic, and transport processes, which ultimately support the capacity for ecdysteroid production by the Y-organ. While cAMP also regulates acute ecdysteroidogenesis to some extent, data indicate that cGMP is the primary signaling molecule responsible for acute inhibition by neuropeptides. It is clear that the regulatory roles filled by cAMP and cGMP are conserved among decapod crustaceans. It is unknown if these complementary second messengers are linked in a single signaling pathway or are components of independent pathways activated by different factors present in extracts of eyestalk ganglia.  相似文献   

5.
Five novel neuropeptides, designated Pm-sgp-I to -V, of the crustacean hyperglycemic hormone (CHH) family have been identified from the giant tiger prawn Penaeus monodon by isolation of the preprohormone genes from an eyestalk complementary DNA library. On the basis of sequence similarity, the encoded peptides have been classified as CHH-like type I hormones, which include all known CHHs and the molt-inhibiting hormone (MIH) of the lobster Homarus americanus. Consistent with CHH type I preprohormones, the Pm-sgp precursors include a signal peptide, a CHH precursor-related peptide (CPRP), and the CHH-like hormone. Analysis by electrospray ionization-Fourier transform mass spectrometry enabled the neuropeptide complement of individual sinus glands to be resolved. It also confirmed the presence of the five Pm-sgp neuropeptides within the sinus gland of an individual animal, in that the masses observed were consistent with those predicted from the gene sequence of the Pm-sgps after posttranslational modification. These modifications included cleavage of the signal peptide and precursor protein, carboxy-terminal amidation, and formation of three disulfide bridges. Analysis of crude extracts of single sinus glands from different animals revealed variation in neuropeptide content and will provide a tool for determining whether the content varies as a function of the physiological state of the animal. Received March 26, 1999; accepted September 10, 1999.  相似文献   

6.
Crustacean hyperglycemic hormone (CHH), a physiologically important neurohormone stored in the sinus gland of eyestalks, primarily regulates carbohydrate metabolism and also plays significant roles in reproduction, molting and other physiological processes. In the freshwater giant prawn, Macrobrachium rosenbergii, an injection of X-organ sinus gland (XOSG) extract evoked a hyperglycemic response, peaked in 1 h. The hyperglycemic effect of the eyestalk extract was maximal at the dose of 0.5 eyestalk equivalent. CHH fractionated by RP-HPLC, in M. rosenbergii was identified by its hyperglycemic activity and partial amino acid sequence, and the molecular weight of 8534 was determined by matrix-assisted laser desorption ionization mass spectrometry--time of flight analysis (MALDI-TOF). The amino acid sequence of the first 25 residues of CHH showed 72% homology with the first 25 residues of CHH A and CHH B of the American lobster Homarus americanus.  相似文献   

7.
Nithya  M.  Munuswamy  N. 《Hydrobiologia》2002,486(1):325-333
Localization of crustacean hyperglycemic hormone (CHH) activity in the brain ganglia of Streptocephalus dichotomus was demonstrated by immunocytochemical method. For this, two different rabbit antisera, one raised against a crayfish Orconectus limosus, and the other with a crab Carcinus maenas, were used. Positive immunoreactivity was recorded with the antibody raised against Orconectus limosus CHH. However, the antibody raised against the CHH of the crab, Carcinus maenas failed to show any cross-reactivity. The biological specificity of these peptides was further confirmed by immunoblotting and immunodiffusion studies performed with the partially purified CHH. The results obtained with the immunodot-blotting and immunodiffusion studies with CHH, further confirmed the immunocytochemical studies. Bioassay experiments performed with a freshwater prawn, Macrobrachium rosenbergii indicate the interspecific biological activity of this neuropeptide. The present study indicates that besides the sinus gland, there are other sites of CHH synthesis and release in the brain ganglia of S. dichotomus.  相似文献   

8.
9.
Crustacean hyperglycemic hormone (CHH), a neurohormone synthesized and released from the x-organ sinus gland complex, is primarily involved in carbohydrate metabolism; biogenic amines and peptidergic neuroregulators are known to modulate the release of CHH. Marked elevations of hemolymph glucose titers, which peaked within 2 h, were observed in both intact and bilaterally eyestalk-ablated prawns, Macrobrachium rosenbergii, when they were transferred directly from their optimal temperature of 28 °C to lower temperatures close to their lethal limit. Hyperglycemia can therefore be considered a characteristic response in this species under cold shock. Involvement of biogenic amines in the hyperglycemic response was also demonstrated. Hyperglycemic effects of epinephrine, dopamine and serotonin were mediated through CHH at the eyestalk level, but the response under cold shock was not exclusively mediated through CHH. It is suggested that factor(s) other than CHH are involved in the hyperglycemic response, possibly norepinephrine or/and octopamine. Accepted: 24 October 1998  相似文献   

10.
The crustacean hyperglycemic hormone (CHH) peptides regulate diverse physiological processes from reproduction to metabolism and molting in arthropods. In insects, the ion transport peptides (ITP), also members of the CHH family, have only been implicated in ion transport. In this study, we sequenced a nucleotide fragment spanning the conserved A1/A2 region of the putative CHH/ITP gene. This fragment was amplified from larval cDNA of the tobacco hornworm, Manduca sexta and showed a high degree of sequence conservation with the same region from other insects and, to a lesser degree, with that of crustacean species, suggesting the presence of a Manduca-specific CHH/ITP mRNA (MasITP mRNA). CHH-like immunocytochemical analyses with two crustacean antisera (from Carcinus maenas and Cancer pagurus) identified the presence of CHH-like immunoreactivity in nervous tissue of all developmental stages, but not in the gut of M. sexta. Specifically, CHH-like peptides localized to paired type IA2 neurosecretory cells of the pars lateralis of the brain (projecting ipsilaterallly to the corpora cardiaca-allata complex) and to neurosecretory cells and transverse nerves of the ventral nerve cord in larvae, pupae, and adults. The distribution of the putative MasITP peptide shifted during development in a manner consistent with metamorphic reorganization. A comparison of hemolymph equivalents of CHH detected by enzyme-linked immunosorbent assay with CHH-like immunoreactivity in transverse nerves provided evidence for the release of MasITP from the transverse nerves into the hemolymph at insect ecdysis. These data suggest the presence of an insect ITP in M. sexta and a role for this hormone during ecdysis. This research was funded by the National Institutes of Health (MBRS SCORE Program-NIGMS) to M.F. (grant no. 2S06 GM52588-09), by the National Center on Minority Health and Health Disparities (grant no. 5P20-MD000262), an NIH RISE graduate fellowship to A.L.D. (5 R25 GM59298), an NIH PREP fellowship to C.C.H. and M.A.U. (5 R25 GM64078), an NSF CSU LS-AMP fellowship to C.C.H. (HRD-9802113), and by NIH MBRS-MARC to M.D.P. (T34 GM08574) and NIH MA/MS-PhD Bridge Scholarship to A.L.D. and C.C.H. (5R25 GM48972).  相似文献   

11.
Mandibular organs (MO) produce a crustacean juvenile hormone, methyl farnesoate (MF). MO activity is negatively regulated by factors, called mandibular organ inhibiting hormones (MOIHs), from the crustacean sinus gland X-organ complex in the eyestalks. Three MOIHs have been isolated previously from the spider crabLibinia emarginata and are characterized as members of the crustacean hyperglycemic hormone (CHH) neuropeptide family. In the research reported here, a full length cDNA sequence of 972 bp of a MOIH was isolated by screening a cDNA library constructed from the eyestalks ofLibinia emarginata. This cDNA sequence encodes a preprohormone peptide with 137 amino acid residues, including a 26-amino acid long signal peptide, a 34-amino acid long precursor peptide, a dibasic peptide, the full length of 72-amino acid long MOIH, and a tri-peptide Gly-Lys-Lys which designates the potential amidation site at the C-terminus of the mature peptide.  相似文献   

12.
Ultrasonic telemetry was used to analyze the effects of environmental variables on movement directions and movement rates of brown smoothhounds, Mustelus henlei, in Tomales Bay, California. Ultrasonic transmitters were surgically implanted in the peritoneal cavities of one male and five female brown smoothhounds and tracked during the period of 29 June to 15 July 2004. Coarse-scale tracking consisted of locating all tagged individuals multiple times during a single session, while fine-scale tracking consisted of following a single individual continuously during a session. Coarse-scale tracking suggested movement toward the inner bay with incoming and high tides and toward the outer bay with outgoing and low tides (P = 0.01), whereas the diel cycle had no apparent effect on their movement directions. Mean shark movement rate was 0.09 m s−1 (range: 0.01–0.34 m s−1), with diel and tidal cycles both having significant effects on their rates of movement (P = 0.02 and P < 0.01), respectively. We tracked two female sharks on a fine scale over three tracking sessions in July 2004. Both individuals exhibited higher rates of movement during the night compared to the day (P < 0.01). While one shark’s rate of movement was not significantly affected by tidal stage, the other’s was (P < 0.001).  相似文献   

13.
The tissue-specific expression and differential function of the crustacean hyperglycemic hormone (CHH) in Carcinus maenas indicate an interesting evolutionary history. Previous studies have shown that CHH from the sinus gland X-organ (XO-type) has hyperglycemic activity, whereas the CHH from the pericardial organ (PO-type) neither shows hyperglycemic activity nor it inhibits Y-organ ecdysteroid synthesis. Here we examined the types of selective pressures operating on the variants of CHH in Carcinus maenas. Maximum likelihood-based codon substitution analyses revealed that the variants of this neuropeptide in C. maenas have been subjected to positive Darwinian selection indicating adaptive evolution and functional divergence among the CHH variants leading to two unique groups (PO and XO-type). Although the average ratio of nonsynonymous to synonymous substitution (omega) for the entire coding region is 0.5096, few codon sites showed significantly higher omega (10.95). Comparison of models that incorporate positive selection (omega > 1) with models not incorporating positive selection (omega <1) at certain codon sites failed to reject (p=0) evidence of positive Darwinian selection.  相似文献   

14.
Summary Using a Y-organ in vitro assay to measure repression of ecdysteroid synthesis in the presence of putative moult-inhibiting hormone (MIH), in conjunction with HPLC separation of sinus gland neuropeptides ofCarcinus maenas, it was found that both the hyperglycemic hormone (CHH) and a novel peptide (argued to represent the MIH) inhibited ecdysteroid synthesis. The latter was purified to homogeneity, and amino acid analysis showed that it is a 61 residue peptide (minimum molecular mass 7,200 Da) with the following amino acid composition: Asx9; Thr2; Ser2; Glx7; Pro1; Gly4; Ala2; 1/2 Cys4; Val4; Met1; Ile3; Leu5; Tyr1; Phe3; His3; Trp2; Lys2; Arg6. The N-terminus appears to be blocked. MIH is at least 20 times more potent than CHH in repressing ecdysteroid synthesis and is active at concentrations of less than 250 pmol/l. There may be structural similarities between CHH and MIH, howeve, MIH displays no CHH radioimmunoreactivity or hyperglycemic activity. The physiological significance of CHH in controlling ecdysteroid titres is not known.Abbreviations CHH hyperglycemic hormone - MIH moult inhibiting hormone - PAGE polyacrylamide gel electrophoresis - RIA radioimmunoassay - SDS sodium dodecyl sulfate - SG smus gland(s) - SGE sinus gland equivalent - TFA trifluoroacetic acid  相似文献   

15.
Summary

Testis sheaths from late last instar larvae and mid-developing pupae of Heliothis virescens and Lymantria dispar synthesize ecdysteroid in vitro. Gonadal ecdysteroid can stimulate the production of growth factors from the sheaths which, in turn, promote the growth and development of the genital tract. Ongoing basal synthesis is controlled by positive feedback to exogenous ecdysteroid; titers of this hormone approaching those of molting last instar larvae and developing pupae effect maximum synthesis. These findings suggest that circulating titers of ecdysteroid hormone promote gonadal ecdysteroidogenesis, and thus coordinate the actions of the gonads with metamorphic events in the whole animal. Synthesis of ecdysteroid by testes is initiated, however, by a brain neuropeptide, testis ecdysiotropin (TE). TE is a 21 amino acid peptide of molecular weight 2472 Da. TE boosts basal steroid synthesis by pupal testis sheaths as well. It acts primarily via Gi protein and second messengers diacyl glycerol and low calcium influx, resulting in stimulation of phosphokinase C. Gs protein and its resultant messenger, cyclic AMP, also play roles in activation and inhibition of ecdysteroidogenesis. The interplay of controlling systems probably serves to fine tune a system essential to gonadal development and function.  相似文献   

16.
The insect prothoracic glands are the source of steroidal molting hormone precursors and the glands are stimulated by a brain neuropeptide, prothoracicotropic hormone (PTTH). Previous work from this laboratory revealed that PTTH acts via a cascade including Ca2+/calmodulin activation of adenylate cyclase, protein kinase A, and the subsequent phosphorylation of a 34 kDa protein (p34) hypothesized, but not proven, to be the 56 protein of the 40S ribosomal subunit. The jmmunosuppressive macrolide, rapamycin, is a potent inhibitor of cell proliferation, a signal transduction blocker, and also prevents ribosomal S6 phosphorylation in mammalian systems. We demonstrate here that rapamycin inhibited PTTH-stimulated ecdysteroidogenesis in vitro by the prothoracic glands of the tobacco hornworm, Manduca sexta, with half-maximal inhibition at a concentration of about 5 nM. At concentrations above 5 nM, there was a 75% inhibition of ecdysteroid biosynthesis. Similar results, were observed with the calcium ionophore (A23187), a known stimulator of ecdysteroidogenesis. Most importantly, the inhibition of ecdysteroid biosynthesis was accompanied by the specific inhibition of the phosphorylation of p34, indicating that p34 indeed is ribosomal protein S6. In vivo assays revealed that injection of rapamycin into day 6 fifth instar larvae resulted in a decreased hemolymph ecdysteroid titer and a dose-dependent delay in molting and metamor-phosis. When S6 kinase (S6K) activity was examined using rapamycin-treated prothoracic glands as the enzyme source and a synthetic peptide (S6-21) or a 40S ribosomal subunit fraction from Manduca tissues as substrate, the date revealed that rapamycin inhibited S6K activity. The composite data suggest that rapamycin inhibits a signal transduction element leading to p34 phosphorylation that is necessary for PTTH-stimulated ecdysteroidogenesis in this insect endocrine gland, and lend further support to the concept that p34 is S6. © 1994 Wiley-Liss, Inc.  相似文献   

17.
The eyestalk of Astacus leptodactylus is investigated immunocytochemically by light, fluorescence, and electron microscopy, using an antiserum raised against purified crustacean hyperglycemic hormone (CHH). CHH can be visualized in a group of neurosecretory perikarya on the medualla terminalis (medulla terminalis ganglionic X-organ: MTGX), in fibers forming part of the MTGX-sinus gland tractus, and in a considerable part of the axon terminals composing the sinus gland. Immunocytochemical combined with ultrastructural investigations led to the identification of the CHH-producing cells and the CHH-containing neurosecretory granule type.  相似文献   

18.
To assess functional importance of the residues in the amino- and carboxyl-termini of crustacean hyperglycemic hormone in the mud crab Scylla olivacea (Sco-CHH), both wild-type and point-mutated CHH peptides were produced with an amidated C-terminal end. Spectral analyses of circular dichroism, chromatographic retention time, and mass spectrometric analysis of the recombinant peptides indicate that they were close in conformation to native CHH and were produced with the intended substitutions. The recombinant peptides were subsequently used for an in vivo hyperglycemic assay. Two mutants (R13A and I69A rSco-CHH) completely lacked hyperglycemic activity, with temporal profiles similar to that of vehicle control. Temporal profiles of hyperglycemic responses elicited by 4 mutants (I2A, F3A, D12A, and D60A Sco-CHH) were different from that elicited by wild-type Sco-CHH; I2A was unique in that it exhibited significantly higher hyperglycemic activity, whereas the remaining 3 mutants showed lower activity. Four mutants (D4A, Q51A, E54A, and V72A rSco-CHH) elicited hyperglycemic responses with temporal profiles similar to those evoked by wild-type Sco-CHH. In contrast, the glycine-extended version of V72A rSco-CHH (V72A rSco-CHH-Gly) completely lost hyperglycemic activity. By comparing our study with previous ones of ion-transport peptide (ITP) and molt-inhibiting hormone (MIH) using deleted or point-mutated mutants, detail discussion is made regarding functionally important residues that are shared by both CHH and ITP (members of Group I of the CHH family), and those that discriminate CHH from ITP, and Group-I from Group-II peptides. Conclusions summarized in the present study provide insights into understanding of how functional diversification occurred within a peptide family of multifunctional members.  相似文献   

19.
The alkaline protease gene from Aspergillus oryzae was cloned, and then it was successfully expressed in the heterologous Pichia pastoris GS115 with native signal peptide or α-factor secretion signal peptide. The yield of the recombinant alkaline protease with native signal peptide was about 1.5-fold higher than that with α-factor secretion signal peptide, and the maximum yield of the recombinant alkaline protease was 513 mg/L, which was higher than other researches. The recombinant alkaline protease was purified by ammonium sulfate precipitation, ion exchange chromatography and gel filtration chromatography. The purified recombinant alkaline protease showed on SDS–PAGE as a single band with an apparent molecular weight of 34 kDa. The recombinant alkaline protease was identical to native alkaline protease from A. oryzae with regard to molecular weight, optimum temperature for activity, optimum pH for activity, stability to pH, and similar sensitivity to various metal ions and protease inhibitors. The native enzyme retained 61.18% of its original activity after being incubated at 50 °C for 10 min, however, the recombinant enzyme retained 56.22% of its original activity with same disposal. The work demonstrates that alkaline protease gene from A. oryzae can be expressed largely in P. pastoris without affecting its enzyme properties and the recombinant alkaline protease could be widely used in various industrial applications.  相似文献   

20.
We aimed to assess the feasibility of enhancing the intestinal development of weaned rats using glucagon‐like peptide‐2 (GLP‐2)‐expressing Saccharomyces cerevisiae (S. cerevisiae). GLP‐2‐expressing S. cerevisiae (GLP2‐SC) was generated using a recombinant approach. The diet of weaned rats was supplemented with the GLP2‐SC strain. The average daily gain (ADG), the intestinal morphology and the activities of the digestive enzymes in the jejunum were tested to assess the influence of the GLP2‐SC strain on intestinal development. The proliferation of rat enterocytes was also assessed in vitro. The study revealed that the ADG of the weaned rats that received GLP2‐SC was significantly greater than that of the controls fed a basal diet (Control) and S. cerevisiae harbouring an empty vector (EV‐SC) (P < 0.05) but was equivalent to that of positive control rats fed recombinant human GLP‐2 (rh‐GLP2) (P > 0.05). Furthermore, GLP2‐SC significantly increased villous height (P < 0.01) and digestive enzyme activity (P < 0.05) in the jejunum. Immunohistochemistry analysis further affirmed that enterocyte proliferation was stimulated in rats fed the GLP2‐SC strain, as indicated by the greater number of enterocytes stained with proliferative cell nuclear antigen (P < 0.05). In vitro, the proliferation of rat enterocytes was also stimulated by GLP‐2 expressed by the GLP2‐SC strain (P < 0.01). Herein, the combination of the GLP‐2 approach and probiotic delivery constitute a possible dietary supplement for animals after weaning.  相似文献   

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