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1.
1-methladenine (1-MA) induces starfish oocytes maturation via surface reaction followed by the appearance of a cytoplasmic
maturation factor which in turn induces germinal vesicle breakdown (GVBD) to resume meiosis. Cellular mechanisms involved
in GVBD were investigated by microinjection of metabolic inhibitors. Colchicine (Co) inhibited maturation, cytochalasin-B
(CB) delayed GVBD and actinomycin-D-(Act-D) and puromycin (Pu) had no effect. It appears that the microtubule and the microfilament
systems are associated with the nuclear membrane dissolution during the process of oocyte maturation of starfish. 相似文献
2.
Wang Renxue Wu Xianhan Zhou Jing Zhang Shicui Ma Yingjie Wu Shangqin Shi Yingxian 《中国海洋湖沼学报》1991,9(1):88-93
Full maturation of goldfish oocyte was inducedin vitro by 17 α-hydroxy-20β-dihydroprogesterone. The oocyte maturation involves GV migration to the periphery of the oocyte and germinal
vesicle breakdown (GVBD). In the experiment, incubation duration for GVBD varied in different broods of oocytes. Generally,
if the duration for GVBD was shorter than 6 h, oocytes would have a better chance to survive after maturation and insemination.
The maturation of nucleus (GV) and cytoplasm are not synchronous. Cytoplasm maturation occurs several hs after GVBD. Oocytes
inseminated 8–9 h after GVBD have the highest fertilizing and hatching rate. Fertilized ova maturedin vitro can develop to sexually mature adults capable of reproduction.
Contribution No 1731 from the Institute of Oceanology, Academia Sinica. 相似文献
3.
We investigated the effects of lipopolysaccharide(LPS) and dopamine(DA) on the activation of the prophenoloxidase(proPO) system of Litopenaeus vannamei.LPS and DA were shown with a negative dose-dependent effect on hyalne cells(HC),semi-granular cells(SGC),large granular cells(LGC),and total haemocyte count(THC).When haemocytes were treated with LPS or DA,serine proteinase activity and intracellular phenoloxidase(PO) activity were significantly reduced,but extracellular PO activity increased significantly.These findings indicated that the reduction in haemocyte counts was mainly because of the degranulation and activation of the proPO system from semi-granule and large granule cells.The PKC inhibitor,chelerythrine,and the TPK inhibitor,genistein,had an inhibitory effect on extracellular PO activity,while serine proteinase and intracellular PO activity increased.This suggests that the LPS and DA induce the activation of proPO in haemocytes via PKC and TPK-related signaling pathways,but serine proteinase may be activated only by PKC,as the genistein effects were not statistically significant.Electrophoresis analysis revealed that POs induced by LPS or DA have the same molecular mass and high diphenolase activity.Two PO bands at 526 kDa and 272 kDa were observed in PAGE,while in the haemocyte lysate supernatant(HLS),only a 272-kDa band was observed.This band was resolved after SDS-PAGE under non-reducing and reducing conditions into two groups of POs,166 kDa and 126 kDa,and 78.1 kDa and 73.6 kDa,respectively,suggesting that PO in L.vannamei is an oligomer,which may have different compositions intra-and extracellularly. 相似文献
4.
Fully grown oocytes of Apostichopus japonicus have a cytoplasmic protuberance where the oocyte attaches to the follicle. The protuberance and the oolamina located on the
opposite side of the oocyte indicate the animal-vegetal axis. Two pre-meiotic centrosomes are anchored to the protuberance
by microtubules between centrosomes and protuberance. After meiosis reinitiation induced by DTT solution, the germinal vesicle
(GV) migrates towards the protuberance. The GV breaks down after it migrates to the oocyte membrane on the protuberance side.
The protuberance then contracts back into the oocyte and the first polar body extrudes from the site of the former protuberance.
The second polar body forms beneath the first. Thus the oocyte protuberance indicates the presumptive animal pole well before
maturation of the oocyte. 相似文献
5.
This study aimed to evaluate the potential impacts of an introduced clam Mercenaria mercenaria on estuarine ecosystem, and implications for the niche competition with a native clam Meretrix meretrix. The biodeposition, respiration, and excretion rates of M. mercenaria were determined seasonally using a sediment trap and a closed respirator in field. The biodeposition rates of M. mercenaria were 0.06–0.37 g/ (ind.·d), and the respiration rates were 0.31–14.66 mg/(ind.·d). The ammonia and phosphate excretion rates were 0.18–36.70 and 1.44–14.87 μg/(ind.·d), respectively. The hard clam M. mercenaria may discharge dry deposits up to 2.1×105 t, contribute 18.3 t ammonia and 9.0 t phosphate to culture ponds, and consume 7.9×103 t O2 from ponds annually. It suggested that the hard clam M. mercenaria might play an important role in pelagic-benthic coupling in pond ecosystem through biodeposition and excretion. A comparison of the key physiological parameters of the introduced clam M. mercenaria and the native clam Meretrix meretrix suggested that M. mercenaria had a niche similar to that of Meretrix meretrix in Shuangtaizi estuary and might have a potential competition with Meretrix meretrix for habitat and food if M. mercenaria species escaped from the culture pond or artificially released in estuarine ecosystem. 相似文献
6.
The in vitro effects of steroids, human chorionic gonadotropin (HCG) and cyanoketone on germinal vesicle breakdown (GVBD)
of striped mullet (Mugil cephalus L.) oocytes were investigated. All concentrations of HCG (5,10,50 I.U./ml), progesterone and pregnenolone at the highest
concentrations(lug/ml) were moderately effective in inducing GVBD, whereas 17β-estrodiol, cortisol, testosterone, 11β-hydroxyandrostenedione
and 11-ketotestosterone did not stimulate GVBD. 17α, 20βdihydroxy-4-pregnen-3-one (17α, 20βdiOHprog) and deoxycorticosterone
(DOC) were the most potent steroids in stimulating final oocyte maturation. The results indicate that C21 hydroxylated steroids
are potent inducers of final maturation in mullet. Further, co-incubations with 17β-estradiol, cortisol and testosterone did
not alter the maturation-inducing effects of HCG or 17α,20βdiOHprog. Cyanoketone, a blocker of 3βHSD activity, was only partially
effective in blocking GVBD induced by HCG. This suggests that Δ5 (pregnenolone derived) and Δ4 steroids may be involved in
final oocyte maturation in this species. 相似文献
7.
8.
Localization of a putative epiboly-determining factor in oocytes of the goldfish (Carassius auratus)
It is unknown whether cytoplasmic determinants in goldfish eggs are asymetrically localized before maturation. In this study
fully grown goldfish oocytes with intact germinal vesiles (GVs) were ligated with baby hair loops along desired planes into
two parts, matured in vitro, and inseminated. Embryos developed from the animal halves with GV of oocytes ligated along the
equator were unable to undergo epiboly, while those developed from the GV-containing parts of oocytes ligated along the animal-vegetal
axis were able to. Also, embryos developed from the animal halves obtained from fertilized eggs could undergo epiboly. From
these results, it was postulated that the goldfish's premature oocyte possessed a putative factor in the vegetal hemisphere
which was responsible for epiboly of the embryonic cells.
This work was supported by the NSFC and the “Climb Plan B” (PD-B6-1-1) of the Chinese Commission of Science and Technology.
Contribution No. 2915 from the Institute of Oceanology, Chinese Academy of Sciences. 相似文献
9.
LOCALIZATION OF A PUTATIVE EPIBOLY-DETERMINING FACTOR IN OOCYTES OF THE GOLDFISH (CARASSIUS AURATUS)
It is unknown whether cytoplasmic determinants in goldfish eggs are asymmetrically localized beforematuration. In this study fully grown goldfish oocytes with infact germinal vesicles (GVs) were ligated withbaby hair loops along desired planes into two parts, mature in vitro, and inseminated. Embryos developedfrom the animal halves with GV of oocytes ligated along the equator un unable to undergoepiboly, while those developed from the GV-containing parts of oocytes ligated along the animal-vegetal axiswere able to. Also, embryos developed from the animal halves obtained from fertilized eggs could undergo epiboly. From there results, it was postulated that the goldfish's premature oocyte possessed a putativefactor in the vegetal hemisphere which was responsible for epiboly of the embryonic cells. 相似文献
10.
Polypeptide from Chlamys farreri inhibits UVB-induced apoptosis of HaCaT cells via iNOS/NO and HSP90
Polypeptide from Chlamys farreri(PCF) is a novel marine bioactive product that was isolated from the gonochoric Chinese scallop Chlamys farreri,and was found to be an effective antioxidant in our recent studies.In this study,we investigated the effect of PCF on ultraviolet B(UVB)-induced apoptosis of HaCaT cells and the intracellular signaling pathways involved.Pretreatment with the inducible nitric oxide synthase(iNOS) inhibitor S-methylisothiourea sulfate inhibited UVB-induced apoptosis,indicating that iN... 相似文献
11.
Starfish oocytes with intact germinal vesicles (GVs) were cut along desired planes with glass needles or ligated using silk
thread loops into two parts and allowed to mature in vitro, and inseminated. The experimental results showed that (1) only
the parts with GVs or partial GV contents (PGVCs) cleaved, those without any GV materials did not; but nucleated and non-nucleated
fragments cut from mature eggs were able to divide; (2) the development of animal parts of oocytes containing GVs or PGVCs
was like that of animal fragments of matured oocytes with female pronuclei; most of them gave rise to permanent blastulae,
and just a few formed ectodermal vesicles with a little primary mesenchyme; (3) a large part of vegetal fragments with GVs
or PGVCs, and the vegetal parts of mature eggs without female pronuclei developed into small but normal embryos; (4) the fragments
containing GVs or PGVCs obtained from the oocytes along a plane parallel to the animal-vegetal (A-V) axis developed as normally
as the halves (with or without female pronuclei) severed from mature eggs along the same axis. Based on the data above, it
was concluded that (1) the non-chromatin materials in the oocyte GVs are indispensable for successful fertilization and cleavage
of starfish eggs; (2) some factor (s) located asymmetrically in the vegetal hemispheres of starfish oocytes is (are) responsible
for formation of the archenteron and primary mesenchyme. It is evident from the above findings that the oocyte cytoplasm of
the starfish had already regionalized before the GV break-down.
Contribution No. 1722 from the Institute of Oceanology, Academia Sinica 相似文献
12.
Meretrix meretrix Linnaeus has long been used as traditional Chinese medicine in oriental medicine.The angiogentic activity of the extract of M.meretrix was investigated in this study,using human umbilical vein endothelial cells(HUVECs).Extract of M.meretrix Linnaeus(AFG-25) was prepared with acetone and ethanol precipitation,and further separated by Sephadex G-25 column.The results show that AFG-25 promoted proliferation,migration,and capillary-like tube formation in HUVECs,and in the presence of eNOS inhibitor NMA,the tube formation induced by AFG-25 is inhibited significantly.Moreover,AFG25 could also promote the activation of endothelial nitric oxide synthase(eNOS) and the resultant elevation of nitric oxide(NO) production.The results suggested that M.meretrix contains active ingredients with angiogentic activity and eNOS/NO signal pathway is in part involved in the proangiogenesis effect induced by AFG-25. 相似文献
13.
An exopolysaccharide (EPS) was isolated and purified from an Antarctic psychrophilic bacterium B-3, identified as Psychrobacter sp., and the activation of RAW264.7 cells by B-3 EPS was investigated. The results show that B-3 EPS, over a certain concentration range, promoted cell viability, nitric oxide production, tumor necrosis factor (TNF)α secretion, and phagocytic ability. Furthermore, TAK-242, an inhibitor of the toll-like receptor 4 (TLR4) significantly reduced nitric oxide production by these cells after stimulation with B-3 EPS. Moreover, B-3 EPS induced p65 phosphorylation and IκBα degradation in these cells. In conclusion, B-3 EPS might have activated RAW264.7 cells by combining with TLR4 on cell surface and triggering activation of NF-κB signaling pathways, implying that this EPS could activate macrophages and regulate initial immune response. 相似文献
14.
Cadmium(Cd) mainly derived from anthropogenic emissions can be transported through atmospheric pathway to marine ecosystem,affecting the phytoplankton community and primary productivity.In this study,we identified the toxicity threshold of Cd for phytoplankton under seawater conditions of the coastal East China Sea(ECS) through both laboratory and in situ mesocosm incubation experiments.The mesocosm experiment showed that Cd in low concentration(0.003 μg per μg chl a) was conducive to the growth of natural community and increased chl a productivity.In high concentration(0.03 μg per μg chl a) Cd acted as an inhibiting factor which decreased the total chl a productivity.The diatom community was found to be more sensitive to Cd toxicity than dinoflagellate,as the low concentration Cd showed toxicity to diatom but enhanced dinoflagellate growth.We noticed that the soluble Cd estimated from atmosphere deposition to the coastal ECS was below the toxicity threshold and the Cd deposition might promote phytoplankton growth in this region.In our laboratory experiments,adding Cd,similar to aerosol deposition,stimulated the growth of both dominant algal species Prorocentrum donghaiense Lu(dinoflagellate) and Skeletonema costatum(diatom).Adding Cd on a higher level inhibited the growth of both the species,but Skeletonema costatum seemed obviously more sensitive to toxicity.This indicates the potential impact of atmospheric deposition Cd on phytoplankton community succession in the ECS. 相似文献
15.
《中国海洋大学学报(英文版)》2021,(3)
The PI3 K/Akt/m TOR signaling pathway is one of the most frequently dysregulated pathways in cancer. Targeting the PI3 K-mediated pathway has been an important strategy for developing novel anticancer agents. In the past decades, more than 40 inhibitors of the PI3 K/Akt/m TOR pathway have been developed at different clinical stages. Temsirolimus, everolimus, idelalisib, and copanlisib have been approved for clinical use by the Food and Drug Administration of the United States(FDA). However, the toxicity and drug resistance limit their efficiency in the treatment. Novel compounds with greater potency and selectivity, as well as improved therapeutic indices with reduced toxicity, are clearly required. Over the past three decades, a lot of bioactive ingredients with anticancer effects by affecting the PI3 K-mediated pathways have been found from marine organisms. In the present mini-review, anticancer compounds from marine source that target the PI3 K/Akt/m TOR signaling were reviewed. The molecular entities and their modes of action were presented. The marine compounds targeting special factors of the PI3 K/Akt/m TOR were highlighted. 相似文献
16.
Seasonal variations in the biochemical composition and the reproductive cycle of pen shell Atrina pectinata in Bohai Sea were investigated from May 2013 to April 2014. Histological analysis indicated that the reproductive cycle of A. pectinata can be divided into two phases, inactive stage and gametogenesis, which were equally and significantly influenced by seawater temperature and food availability. Gametogenesis began in late autumn (October), and completed in June and July. Spawning took place in August, coinciding with the highest water temperature and the richest phytoplankton. The significantly high glycogen content in adductor muscles sustained throughout the late active and ripeness stages, but plummeted during spawning and inactive stages. The protein content in female gonads exhibited a synchronous increase along with oocyte diameter and lipid content, suggesting that the female gonads could accumulate protein and lipid for vitelline in A. pectinata. Furthermore, the RNA/DNA ratio was found to be a useful index to indicate the level of gonad maturation in both males and females. The findings of the present study provided a foundation for the fishery resource administration and the aquaculture development of this species. 相似文献
17.
Plants possess effective mechanisms to respond quickly to the external environment.Rapid activation of phosphatidylinositol-specific phospholipase C(PLC)enzymes occurs after a stimulus.The PLC in Dunaliella salina play s important roles in growth and stress responses.However,the molecular basis of PLC action in D.salina remains little understood.To gain insight into the potential biological functions of this enzyme,we cloned a phospholipase C gene from D.salina in a previous study,named DsPLC(GenBank No.KF573428).Here,we present the prokaryotic expression,purification,and characterization of the DsPLC gene.The entire coding region of DsPLC was inserted into an expression vector pET32 a,and the DsPLC gene was successfully expressed in Escherichia coli.The DsPLC protein was purified and identified using a polyclonal antibody and western blotting.Expressing DsPLC fused with a green fluorescent protein(GFP)in onion showed that DsPLC-GFP was localized to the intracellular membrane.Quantitative real-time PCR analysis revealed that the relative expression of the DsPLC gene was induced significantly by 3.0-mol/L NaCl at 4 h.Our results support the importance of PLC enzymes in plant defense signaling.This study provides a basis for further functional studies of the DsPLC gene and for additional analysis of the potential roles of PLC enzymes in response to abiotic stress. 相似文献
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20.
Volatile organic compounds in marine algae have been reported to comprise characteristic flavor of algae and play an important role in their growth, development and defensive response. Yet their biogeneration remain largely unknown. Here we studied the composition of volatile compouds in Pyropia yezoensis and their variations in response to methyl jasmonate (MeJA) and diethyldithiocarbamic acid (DIECA) treatment using gas chromatography-mass spectrometry (GC-MS). A total of 44 compounds belonging to the following chemical classes (n) were identified, including aldehydes (11), alcohols (8), acids and esters (6), alkanes (5), ketones (5), alkenes (3), and S- or N-containing miscellaneous compounds (6). External treatment with plant hormone MeJA increased the content of 1-dodecanol, 4-heptenal, and 2-propenoic acid-2-methyl dodecylester, but decreased the content of phytol, 3-heptadecene, 2-pentadecanone, and isophytol. When pretreated with DIECA, an inhibitor of the octadecanoid pathway leading to the biosynthesis of endogeneous jasmonates and some secondary metabolites, phytol and isophytol were increased, while 4-heptenal, 1-dodecanol, and 2-propenoic acid-2-methyl dodecylester were decreased, both of which were negatively correlated with their variations under MeJA treatment. Collectively, these results suggest that MeJA does affect the volatile composition of P. yezoensis, and the octadecanoid pathway together with endogenous jasmonate pathway may be involved in the biosynthesis of volatile compounds, thereby providing some preliminary envision on the composition and biogeneration of volatile compounds in P. yezoensis. 相似文献