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排序方式: 共有224条查询结果,搜索用时 46 毫秒
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M.A. Khan A. Doderer A.B. Koopmanschap C.A.D. de Kort 《Journal of insect physiology》1982,28(3):279-284
Assay conditions for the short-term, radiochemical, in vitro determination of the spontaneous rate of juvenile biosynthesis by isolated corpora allata from Leptinotarsa decemlineata have been further improved, permitting the measurement of juvenile hormone biosynthesis by individual pairs of corpora allata. The final incubation product has been identified as juvenile hormone III with the aid of High-performance liquid chromatography (HPLC) and juvenile hormone esterase degradation. Using the new assay conditions, the activities of adult corpora allata during maturation were found to be significantly higher in reproductive, long-day animals than in pre-diapause, short-day beetles. During diapause no activity was detectable, whereas corpora allata from post-diapause beetles were reactivated totally after 5 days. Simultaneous determination of the in vitro rates of juvenile hormone biosynthesis and corpus allatum volumes revealed no clear correlation although the results suggest that the volume may be indicative of the maximal capacity for juvenile hormone production. Corpora allata from a population of beetles did not display any synchronous diurnal rhythmicity. 相似文献
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For up to three days after being treated with the precocene analogue 6-methoxy-7-ethoxy-2,2-dimethylchromene, adult green peach aphids (Myzus persicae) gave birth to offspring (alate and apterous virginoparae, males) which underwent precocious metamorphosis. Only a few precocious gynoparae and no precocious oviparae were recorded. The precocious aphids became adultoid in the third or fourth-instar as a result of corpus allatum destruction. They were able to develop mature embryos, but could not deposit them because of incomplete differentiation of the reproductive tract. The treatment did not induce the production of alate virginoparae in the experimental clone of Myzus persicae. However, a few males were born late in the reproductive sequence of treated apterae. The corpora allata of the treated adults appeared on histological examination to be unaffected by precocene. 相似文献
4.
V.B. Awasthi 《Journal of insect physiology》1976,22(9):1181-1186
The ultrastructure of the retrocerebral endocrine-aortal complex of the earwig, Euborellia annulipes has been studied. The space between the inner and outer stromal layers of the aorta is occupied by numerous axon terminals and pre-terminals containing large electron dense granules (NS-I) of approximately 100 to 220 nm and a few axon terminals having small granules (NS-II) of approximately 40 to 90 nm; the former appear to belong to medial neurosecretory A-cells, and the latter to the B-cells of the brain. The corpora cardiaca consist of intrinsic cells with mitochondria and multivesicular bodies. Granules of type NS-II and NS-III are observed in the axon terminals and pre-terminals in the corpora cardiaca. The NS-II are identical to those found in the aorta and are probably the secretions of the lateral B-cells. Granules of type NS-III are 40 to 120 nm and electron dense, and are intrinsic in origin. Similar granules occur in the intrinsic cells of the corpora cardiaca. E M studies have confirmed the rôle of the aorta as a neurohaemal organ for the medial neurosecretory cells, and the corpora cardiaca for the lateral neurosecretory cells of the brain. The corpora cardiaca also act as a reservoir for the intrinsic secretion. The corpus allatum is a solid body consisting of parenchymal cells with prominent nuclei, mitochondria, and endoplasmic reticulum. In between its cells are occasional glial cells and also neurosecretory as well as non-neurosecretory axons. The gland is devoid of A-cell NSM. 相似文献
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Weixiang He Jianmin Liu Daoquan Liu Jundong Hu Ye Jiang Mingzhou Li Qian Wang Ping Chen Guang Zeng Deqiang Xu Xinghuan Wang Michael E. DiSanto Xinhua Zhang 《Journal of cellular and molecular medicine》2020,24(24):14280
To explore how alterations in the phosphodiesterase type 5 (PDE5) signalling pathway and oxidative stress correlate with changes in the expression of relaxation and contraction molecules and erectile dysfunction (ED) in the corpus cavernosum smooth muscle (CCSM) of spontaneously hypertensive rats (SHR). In this study, SHR and Wistar‐Kyoto (WKY) rats were used. Erectile function was determined by apomorphine test and electrical stimulation (ES) of cavernous nerve. Masson''s trichrome staining and confocal microscopy were performed. Nitric oxide synthase (NOS), PDE5, phosphorylated‐PDE5 and α1‐adrenergic receptor (α1AR) were determined by RT‐PCR and Western blotting while oxidative stress in CC was determined by colorimetric analysis. SHR exhibited obvious ED. CC of SHR showed less SM but more collagen fibres. The expression of NOS isoforms in SHR was significantly decreased while all α1AR isoforms were increased. In addition, PDE5 and phosphorylated‐PDE5 were down‐regulated and its activity attenuated in the hypertensive rats. Meanwhile, the SHR group suffered oxidative stress, which may be modulated by endoplasmic reticulum stress and NADPH oxidase up‐regulation. Dysregulation of NOS and α1AR, histological changes and oxidative stress in CC may be associated with the pathophysiology of hypertension‐induced ED. In addition, PDE5 down‐regulation may lead to the decreased efficacy of PDE5 inhibitors in some hypertensive ED patients and treatment of oxidative stress could be used as a new therapeutic target for this type of ED. 相似文献
6.
子宫内膜癌(uterine corpus endometrial carcinoma, UCEC)是危害女性健康的癌症之一,但其发生发展机制尚不完全清楚。基因的异常表达在细胞癌变过程中发挥着重要的作用。本研究利用生物信息学方法对UCEC中异常表达的基因进行网络调控分析,为UCEC的机制研究及预后治疗提供理论依据。首先,利用"limma"包筛选得到差异表达的RNA分子;接着,利用R软件中的"GDCRNATools"包构建lncRNA-miRNA-mRNAceRNA网络;最后,利用DAVID(TheDatabasefor Annotation,Visualization and Integrated Discovery)、R软件中的"survival"包、MCODE(Molecular COmplex Detection)插件、StarBase数据库等对ceRNA网络中的RNA分子进行综合分析。结果显示,在UCEC中,我们鉴定了1 319个mRNA、68个lncRNA及100个miRNA为差异表达的RNA分子。同时,利用这些UCEC中的差异表达RNA分子,成功构建了ceRNA网络,结果表明,HCG11、LINC00958、LINC00667、MAGI2-AS3和AC093010.3可能具有ceRNA的功能。通过进一步对该网络成员的分析,结果发现,该网络中的mRNA分子聚集于内皮细胞增殖、细胞骨架和锌离子结合负调控等生物学过程中。生存分析显示,hsa-miR-449a、LINC00958、PKIA和DPYSL2等19个差异表达的RNA分子与UCEC患者预后显著相关。最后,利用MCODE插件对ceRNA网络进行筛选,共获得一个子网络,其成员分别是LINC00667、hsa-miR-449a、hsa-miR-34a-5p和RECK。该研究结果提示,在UCEC的发生发展中存在lncRNA、miRNA和mRNA的差异表达,并且这些RNA分子之间存在ceRNA网络模式的调控,其中一些关键分子与患者的预后相关,这将为进一步研究与理解UCEC的发病机制及预后提供理论依据。 相似文献
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MicroRNA resources in sheep are limited compared with those in other domesticated mammalian species. By sequencing small RNAs of sheep corpus luteum and endometrium, we have generated the largest amount of miRNA-seq data and compiled the most comprehensive list thus far of miRNAs (n = 599) in sheep. Additionally, we observed a highly conserved maternally imprinted cluster of miRNAs on chromosome 18 homologous to that found on chromosome 14 in human and several other eutherian mammals. 相似文献
9.
《Chronobiology international》2013,30(5-6):419-424
A circadian feeding rhythm which may be entrained by photoperiod was found in fifth instarcaterpillars of the lepidopteran, Achaea Janata (L.). AUatectomy reduced the amount of food consumed; this consumption was significantly lower during the fifth instar in both allatectomized and sham-operated insects. An apparent circadian feeding pattern appeared on day 2 in the sham-operated caterpillars. Topical application of the anti-allatin, Precocene-II (50μg/animal) also reduced leaf consumption significantly compared to the respective controls, although these controls maintained the same apparent circadian feeding rhythm on day 2. 相似文献
10.
TOYOMI KOTAKI 《Invertebrate reproduction & development.》2013,57(1-3):225-230
Summary A radiochemical method was adopted to analyze the in vitro products of the corpus allatum (CA) of Plautia stali. The radiolabel derived from 3H-methionine added to the incubation medium was incorporated and released by CA as two main radiolabelled products. They showed Rf values of about 0.3 and 0.5, respectively, in the thin layer chromatography (TLC) system used. The release of these products was shown to be CA-specific since in control incubations using the brain, midgut, aorta and flight muscle, virtually no release of these products was observed. The locations where these main products migrated on the TLC did not coincide with spots of synthetic standards of JH I-III or JHB3, a JH found in higher Diptera. An addition of precursors of JH III, farnesoic acid or farnesol stimulated the CA to biosynthesize the products with an Rf value of 0.5 up to about 10-fold, suggesting that the product in question may have a sesquiterpenoid skeleton similar to JH III. Topical applications of the hexane extracts of the medium in which the CA had been incubated exerted a juvenilizing, metamorphosis-inhibiting effect on final instar nymphs in a dose-dependent fashion. The nymphs treated with the hexane extracts at a high dose moulted to intermediates with reduced forewings and scutellum, as well as nymphs implanted with the CA from reproductively active females. Based on this juvenilizing effect found in the hexane extracts, the JH-active fraction was determined after TLC separation. This assay indicated that the products found at an Rf value of about 0.5 was JH-active. These results suggest the presence of a new JH different from any known JHs in P. stali. 相似文献