首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 156 毫秒
1.
Most insects must accumulate glycogen before entering diapause. Photoperiod influences diapause beyond the maternal generation in Cotesia vestalis (Haliday) (Hymenoptera: Braconidae). In this study, we measured glycogen content and the activity and messenger RNA (mRNA) expression of glycogen synthase and glycogen phosphorylase at different G0 (25 °C under light:dark photoperiods of 8L:16D, 12L:12D, and 16L:8D) and G1 life stages (13 °C under 8L:16D). Glycogen content in G0 and G1 increased with shorter light periods, except for G0 adult males, which showed no significant difference under the three photoperiods. Compared with those under 16 h, in those under 8 h light, glycogen synthase activity was significantly higher at all tested stages, except for G0 pupa and adult male, for which it was identical; mRNA expression was higher at G0 larva and prepupa, lower at pupa, and identical at rest stages. Glycogen phosphorylase activity was significantly higher for G1 egg, lower at G1 prepupa, and identical at all other stages; mRNA expression was higher at G0 and G1 larval stages, and similar at rest stages. These findings suggest that glycogen, being regulated by the two enzymes, may be a consequential factor in the transmission of maternal information and diapause induction of C. vestalis.  相似文献   

2.
3.
4.
Steroid receptor coactivator (SRA), a class of genes encoding both functional RNA and protein, has been shown to be present in vertebrates but little is known in invertebrates. Here we isolated a cDNA encoding a SRA homolog from amphioxus Branchiostoma japonicum, named AmphiSRA. The cDNA contained a 525 bp open reading frame corresponding to a deduced protein of 174 amino acids with a predicted molecular mass of ~21 kDa. Phylogenetic analysis showed that AmphiSRA was located at the base of its vertebrate counterparts, suggesting that it represents the archetype of vertebrate SRA. The genomic DNA sequence of AmphiSRA contained four exons and three introns, which was similar to B. floridae SRA exon/intron organization. The recombinant SRAP expressed in vitro shows a band with a molecular mass of 21 kDa and western blot confirmed it, which proved it is an encoding isoform. AmphiSRA is found to display a tissue specific expression pattern, with a predominant expression in gill, intestine, testis, neural tube and notochord. The whole-mount in situ hybridization demonstrated the expression of AmphiSRA in all the stages of development assayed. These implicated that SRA maybe play an important role during embryonic development of cephalochordate amphioxus.  相似文献   

5.
As-NUPR1, a stress-related protein, plays an important role in post-diapause during embryonic development in the brine shrimp Artemia sinica. In the present study, successful expression of As-NUPR1 from the cDNA sequence isolated from A. sinica was demonstrated using a prokaryotic expression system. The recombinant protein consisted of 132 amino acids with a molecular weight of 15 kDa, and a predicted isoelectric point of 7.17. As-NUPR1 polyclonal antibodies were prepared by immunization of Balb/c mice with purified recombinant As-NUPR1 protein as an antigen, and immunological studies were carried out. Expression of As-NUPR1 during different developmental stages of the embryo and in response to salinity stress was analyzed in A. sinica using Western blots. The experimental results showed that the expression of As-NUPR1 is widely distributed at different developmental stages in A. sinica, and there was no tissue or organ specificity. Expression of As-NUPR1 decreased gradually during the diapause termination stage of embryo development, after which there was a general increase in expression after breaking the shell. In addition, As-NUPR1 expression was highly upregulated under conditions of high salinity. These results suggest that the As-NUPR1 protein is a stress-related protein that plays a role in protecting embryos from high salt damage in different embryonic developmental stages, especially during the post-diapause period.  相似文献   

6.
The activity of glycogen phosphorylase (GPase) in the active a-form (GPase a) is dependent on the hydration state of hepatocytes. We establish that GPase a catalysis in catfish (Ameiurus nebulosus) hepatocytes is a function of medium osmolarity and that a linear relationship exists between GPase a activity and osmolarity between 254 mosmol l–1 and 478 mosmol l–1. Exposure of isolated hepatocytes to hyperosmotic media increases enzyme activity up to 7-fold, indicative of covalent phosphorylation. GPase activation associated with cell shrinkage peaks within 10 min of exposure. The average degree of activation (2.7-fold-increase of GPase a) is only slightly less than in hepatocytes exposed to glucagon (3.1-fold-increase) under isosmotic conditions; with glucagon, the maximum is reached within 2 min. Phosphorylation status remains elevated during the entire 40 min experimental period; cells do not undergo regulatory volume increase (RVI) during this period and do not regain pre-exposure volume. We interpret the increased GPase a activity as an inherent response to hyperosmotic stress, likely brought about by molecular crowding. Activation of the enzyme results in increased glucose production from endogenous glycogen. Glucose is not retained in the liver cells, but may act as an oxidative substrate in extrahepatic tissues for the increased metabolic demand of ion regulation. Protein kinase A or intracellular Ca2+ make apparently small contributions to the activation of GPase, leaving us to speculate on alternate routes of enzyme activation. Conversely, hepatocyte swelling in hyposmotic medium leads to significant decreases in GPase a activity and curtailed glucose output. A minimum is attained in 10 min, and pre-insult rates are re-established within 40 min, somewhat lagging behind readjustment in cell volume by regulatory volume decrease (RVD). We conclude that cell swelling and subsequent RVD do not signify stress to the cells and metabolic demand may be decreased under cell swelling conditions. Alteration of GPase phosphorylation with extracellular osmolarity appears to be a general phenomenon, since we also find it in hepatocytes of another freshwater catfish (Clarias batrachus) and a marine scorpaenid (Sebastes caurinus).Abbreviations BAPTA 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid - BSA bovine serum albumin - cAMP adenosine 3',5-cyclic monophosphate - GPase glycogen phosphorylase - MDH malate dehydrogenase - MHM modified Hanks medium - PKA c-AMP dependent protein kinase A - 8-Br-Rp-cAMPS 8-Bromo-Rp-3',5'-cyclic adenosine monophosphorothioate - RT room temperature - RVD regulatory volume decrease - RVI regulatory volume increaseCommunicated by L.C.-H. Wang  相似文献   

7.
Elongator proteins comprise six subunits (ELP1–ELP6) and form protein complexes. The elongator protein 2 gene (elp2) encodes a protein with a WD40 repeats domain that acts as a scaffold for complex assembly. It also plays an important role in growth and development. In this study, the full-length cDNA of elongator protein 2 (Ajelp2) was cloned from the sea cucumber Apostichopus japonicus (A. japonicus) using rapid amplification of cDNA ends PCR techniques and comprised 3,058 bp, including a 54 bp 5′ untranslated (UTR), a 526 bp 3′ UTR and a 2,478 bp open reading frame encoding a polypeptide of 825 amino acids. The Ajelp2 sequence showed high homology to 12 other species. The molecular weight and isoelectric of point the presumptive protein were 91.6 kDa and 5.84, respectively. In situ hybridization indicated that the gene is expressed in the body wall, intestine, respiratory tree and longitudinal muscle. The expression level of Ajelp2 increased in recovering of organs in sea cucumber and showed it’s the highest expression level at the 15th day in the intestine and respiratory tree. Its expression then gradually decreased to normal levels. In the body wall, the expression level of Ajelp2 was up-regulated and then down-regulated. These results indicated that Ajelp2 is involved in protein regulation during the regeneration process in the sea cucumber A. japonicus.  相似文献   

8.
9.
MicroRNAs (miRNAs) are endogenous non-protein coding RNA molecules of approximately 21 nucleotides in length capable of modulating gene expression in animals and plants. The role of miRNA based gene regulation has been proved in several pathways including in plant growth, development and stress response. In this study miR171 and miR397a were tested for their expression pattern under different heat shock regimes in shoot and root tissues of Arabidopsis thaliana using Locked Nucleic Acid (LNA) mediated in situ hybridization. With an increase in temperature across 35 °C, 40 °C and 45 °C there was a corresponding increased up-regulation of miR171 in leaf tissues compared to ambient temperature. Similarly, an unambiguous elevated expression of miR171 within increase in duration of exposure at each temperature regime across 1 h, 2 h and 3 h was noticed in comparison to ambient control leaf tissue. On the other hand, miR397a, which expressed at ambient control conditions, got down-regulated both with increase in heat and exposure regime in leaf tissues. Both miRNAs expressed in control ambient root tissues. Maintaining the root zone temperature at ambient conditions, upon imposing heat shock regime to shoot system, miR171 recorded corresponding increased up-regulation as indicated by the intensity of in situ hybridization, while miR397a got down-regulated. Given the differential homogeneity in expression pattern of both miRNA in leaf and root tissues experiencing heat shock regimes, possibilities of movement of heat shock induced signals to root tissues seem to be obvious.  相似文献   

10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号