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1.
Chromosome behavior in meiosis was studied by ail-drying, C-banding and surface-spreading methods in female intersexes of artificial triploid transparent-colored crucian carp (Corassius auratus). Chromosome pairing and contraction were obviously asynchronous. The preferential pairing of two homologous chromosomes was the major pattern of chromosome pairing, and a few triple pairing, repeated pairing, telomere or centromere associating and multiple pairing were also observed in the pachytene cells. The metaphase I cells were main-ly composed of univalents, bivalents and trivalents, as well as a few of other multivalents, such as tetravalents, pentavalents, hexavalents and heptavalents, were also found in some metaphase I cells. The chromosome elements including uni-, bi-, tri- and other multivalents varied considerably among the metaphase I cells, and the associating patterns of multivalents were also diverse. Some 6 n and 12 n cells, in which premeiotic endomitosis occurred once or twice, were found at  相似文献   

2.
This study was carried out to assess the spermicidal action of hexane extract from the fruits of Piper longum Linn. The sperm immobilisation studies showed that 20 mg/mL of hexane extract was able to immobilise sperms completely within 20 s. The sperm revival test revealed that the effects were spermicidal as sperm immobilisation effect was irreversible. There was also a significant reduction in sperm viability in the treated group in comparison to the control. The hypo-osmotic swelling of these sperms was significantly reduced, indicating that the hexane extract may probably cause injury to the sperm plasma membrane. Hence, this study showed that the hexane extract of P. longum possesses potential contraceptive spermicidal activity in vitro.  相似文献   

3.
Affinity chromatography was used to separate two components A and B of the crystalline arrowhead proteinase inhibitor. Both A and B are double-headed and multifunctional proteinase inhibitors. Inhibitor A is capable of inhibiting equimolarly trypsin and chymo-trypsin simultaneously, and has a weak inhibitory activity toward kallikrein; whereas inhibitor B can inhibit two molecules of trypsin simultaneously, and shows rather higher inhibitory activity toward kallikrein than inhibitor A, but its inhibitory activity toward chymo-trypsin is much weaker than that of inhibitor A. The results of chemical modification and the competitive binding of trypsin and chymotrypsin with inhibitor A showed that the two reactive sites of both inhibitors A and B are Lys and Arg residues. Among them the Lys reactive site is specific for inhibiting mainly trypsin, whereas the active domain composed of the Arg reactive site appears to be multifunctional and capable of inhibiting many different Ser proteinases. Based on the st  相似文献   

4.
We determined the oil content, fatty acid composition, and cholesterol content of common carp (Cyprinus carpio), crucian carp (Carassius carassius), chub (Leusiscus cephalus), and tench (Tinca tinca) by GLC. The saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) levels were found to be 36.49%, 31.92%, 31.59% in common carp; 32.92%, 32.21%, and 34.87% in crucian carp; 36.19%, 32.91%, and 30.90% in chub; and 32.86%, 30.77%, and 36.37% in tench, respectively. The cholesterol (mg/100 g oil) levels of common carp, crucian carp, chub, and tench were determined by GLC methods as 119 ± 2.64 mg, 170.37 ± 2.36 mg, 94.68 ± 3.13 mg, and 179.84 ± 6.75 mg, respectively. Thus, the cholesterol contents of the analyzed freshwater fish species were low but their PUFA contents and nutritional values were high. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 15–17, January–February, 2009.  相似文献   

5.
Qian Luo  Minghung Wong  Zongwei Cai   《Talanta》2007,72(5):1644-1649
Analytical method using mass spectrometric techniques was applied for the determination of polybrominated diphenyl ethers (PBDEs) in freshwater fishes. Fish samples collected from Nanyang River contaminated by the recycling electron-wastes (e-wastes) materials were prepared by using Soxhlet extraction and multiple-step column chromatographic clean-up. PBDEs were determined by gas chromatography (GC) coupled with ion trap mass spectrometry (for mono- to hepta-BDEs) and quadrupole mass spectrometry (for BDE-209). The method performance was evaluated with the recovery of 13C-labeled internal standards and with the analysis of certified reference biota. The obtained recoveries ranged from 75 to 125% with a relative standard deviation of lower than 10% for 16 PBDE congeners. The total PBDE (ΣPBDE) concentrations in fishes showed the following trend: grass carp < mud carp < crucian carp < silver carp < carp. ΣPBDE concentrations in the abdomen, back and tail muscles of carp ranged from 766, 458 and 530 ng/g w.w., and 53, 52, 45 ng/g w.w. in grass carp, respectively. The ΣPBDE concentrations in abdomen muscles were no significantly higher than in back and tail muscles in carp, crucian carp, grass carp and mud carp. PBDE congener concentrations in muscles correlated well with their lipid content. BDE-47 and BDE-28 were the most abundant congeners followed by BDE-17, BDE-15, BDE-66, BDE-154 and BDE-153 in fishes collected from Guiyu.  相似文献   

6.
A preliminary report on in vitro sperm capacitation and egg-penetration of giant panda is briefly presented. The panda spermatozoon consists of head, neck and tail, just like the spermatozoa of other animals. Before capacitation sperm heads clusterd together and dispersed after capacitation. They were then able to swim straight forwared. During the time of in vitro capacitation the plasm membrane of the sperm head was first expanded tov arious degrees, then disintegrated, and finally became detached. The electro-dense material in the acrosome appeared in small clumps with high density. Extensive vesiculation occurred between the bi-layered acrosome membranes and thus led to disintegration. Vesiculation in panda sperm differs from that reported in hamsters. When the capacitated panda spermatozoa came into contact with the hamster eggs, the region between the acrosome collar and postacrosome cap first fused with the egg membrane followed by the penetration of the nucleus into the cortex of the egg. Some o  相似文献   

7.
红藻中的R-藻红蛋白(R-PE)依照其吸收光谱可分为两种不同的光谱类型,即“双峰型”和“三峰型”。本文通过对不同pH条件下的R-PE的荧光光谱及荧光寿命的研究,发现“三峰型”R-PE的pH稳定范围较“双峰型”R-PE大。在R-PE浓度对荧光光谱的影响实验中,随着蛋白浓度的增加,荧光峰位置逐渐红移。荧光寿命逐渐增大,荧光强度先行增加而后减弱。用碘离子对其荧光进行猝灭,随着碘离子浓度的增大,荧光强度逐渐降低,荧光寿命逐渐缩短,并服从Stem-Volmer规则。  相似文献   

8.
以黑龙江野鲤的吻端和尾鳍组织为材料进行细胞体外培养,所得原代细胞进行传代,并以传至4~10代的尾鳍继代培养细胞作为供体,以同种鲤及鲫成熟具核未受精卵作为受体,采用显微注射方法进行移核,最终获得了发育至原肠胚期的胚胎.  相似文献   

9.
建立了在线凝胶渗透色谱-二维气相色谱/质谱(GPC-MDGC/MS)测定鲫鱼样品中14种农药残留的方法。样品用环己烷/乙酸乙酯(1:1,v/v)提取两次,合并提取液。提取液冷冻、过膜后,经在线凝胶渗透色谱净化后直接进行MDGC/MS分析,通过中心切割的方式将农药组分选择性切割进入二维色谱柱进行进一步分离分析,采用内标法进行定量。实验结果表明:14种农药在0.01~0.9 mg/L范围内具有较好的线性关系,相关系数均大于0.99。14种农药在3个添加水平(0.01、0.05、0.1 mg/kg)的加标回收率为83.0%~112.9%,相对标准偏差为3.2%~12.0%。该方法前处理简单,实现了在线GPC和MDGC的有效结合,准确度好、精密度高,具有很好的推广性。  相似文献   

10.
Abstract

Amphibian egg-jelly coat plays an important role in successful fertilization and development. Here, we ask whether proteins like allurin in the jelly coats of frog eggs might influence fertilization rate success. Using in vitro fertilization of Albanian water frog, Pelophylax shqipericus, we found that body cavity eggs or eggs deprived of jelly coat were not fertilized, compromising the success of in vitro fertilization procedure. When de-jellied eggs were inseminated with sperm suspension, the fertilization efficiency is dramatically decreased even inhibited, suggesting that the gel structure is one of the major factors in the achievement of fertilization in the frogs. Fertilization of de-jellied eggs with sperm pre-treated with egg jelly coat, restored the fertilization competency. Such a result suggests that egg jelly coat probably guides the sperm to the egg surface while maintaining the fertilization ability, contributing to a successful in vitro fertilization of Pelophylax shqipericus.  相似文献   

11.
Common carp, specifically the Jian variety (Cyprinus carpiovar var. Jian), is an important Chinese and global aquatic stock for commercial foodstuff. Homologous recombination of carp gene sequences has been widely used in population genetics to broadly screen for beneficial phenotypical variations, thus optimizing artificially engineered carp stocks with Jian variety and native stock varieties. Random rearrangement of homologous DNA fragments from parent specimens of C. carpiovar var. Jian were attained by digestion of genomic DNA with MspI followed by religation and redigestion with EcoR I to specifically rearrange homologous DNA fragments of myostatin and microsatellite genes. Based on known characteristics of myostatin gene function, growth pattern changes in resultant carp mutant varieties was expected. DNA fragments were introduced into metaphase-II oocytes, resulting in one to several dozen insertions of homologous fragments into the host genome by sperm-mediated transgenesis. Introduction of rearranged homologous DNA fragments often resulted in phenotypic changes in C. carpiovar var. Jian, including significant phenotypic changes linked to growth rate at 4 months.  相似文献   

12.
THE CHARACTERISTICS AND MOTION MODEL OF INSULIN MONOMER   总被引:1,自引:0,他引:1  
The extensive conformational comparisons among the determined structures of the differeat species and crystal forms of insulin and the varied insulin derivatives were performed by using the least-squares superimposition technique and the graphics technique. The results of the investigation showed that the structure of molecule I in 2Zn insulin was closer to that of the natural monomer; the conformational difference between two molecules of a dimer came out during dimerization and it was further improved and stabilized during the hexamerization and packing of hexamers in crystal; through the hinge peptides, such as A10, B4, B8, B24, B20 and B23, there was a flexible relative motion among the structural segments in the insulin molecule, and the residues at the B-chain C-terminal might have a shift of more than 10; the mobility for each residue side-chain was very different due to the different surroundings.  相似文献   

13.
用膨胀计法研究了西氯苯醌(CA)、苯醌(BQ)与受阻胺二异丙胺(DIPA)、2,2,6,6-四甲基-4-羟基哌啶(TMP)形成的电荷转移络合物(CTC)对偶氮二异丁腈(AIBN)引发的甲基丙烯酸甲酯(MMA)自由基聚合阻聚效应。结果表明,CA-DIPA、CA-TMP、BQ-DIPA和BQ-TMP对MMA的自由基聚合均产生较单独的醌或胺更显著的阻聚能力。其中以CA-DIPA阻聚效果更佳。比较了MMA在苯或乙腈中的溶液聚合,得类似结果。初步讨论了受阻胺-醌电荷转移络合物对MMA自由基聚合的阻聚反应机理。  相似文献   

14.
丙烯酸丁酯-醋酸乙烯酯共聚物胶乳粒子的结构和性能   总被引:1,自引:0,他引:1  
电镜观察表明,丙烯酸丁酯-醋酸乙烯酯共聚物胶乳粒子均为核-壳结构,若配料比不同,含量大者为核,而加料方式不同,则先加者先聚合成核.微观结构不同,可明显地影响胶膜的力学性能、Tg和耐水性.根据胶乳粒子微观结构的观察结果,认为当醋酸乙烯酯>50mol%时,共聚的引发和成核是在水相中进行的.  相似文献   

15.
16.
EDTA对均匀胶体粒子形成的影响   总被引:1,自引:0,他引:1  
特殊阴离子是决定金属盐升温水解制备均匀胶体粒子形态的重要因素之一. EDTA的存在强烈影响三价铁盐水解产物-均匀α-Fe_2O_3和β-FeOOH胶体粒子的形态. 其影响机理是EDTA在成长中的微粒子上络合吸附和溶液中的EDTA与Fe~(3+)离子间络合反应的复合结果. 前者趋于形成较大的聚合粒子; 后者趋于形成较小粒子. 进而, 凡是能够改变EDTA络合吸附状态和吸附量的. 存在于陈化液中的一切其它阴离子均会改变EDTA的作用程度.  相似文献   

17.
The aim of this study was to know the protective immunity of broilers immunized with attenuated Eimeria tenella (E. tenella) on homologous and heterologous challenges. The protective immunity was represented by oocyst production and histopathological changes of cecum. The previous experiment already produced attenuated E. tenella through serial passages of precocious lines in naive chicken. Four groups of chickens were separately divided into two non-immunized control groups and two immunized with attenuated E. tenella groups, and each group was challenged with homologous and heterologous strains. The results showed significant difference in oocysts production (p<0.01) and histopathological changes between control and immunized groups.  相似文献   

18.
The carp mitochondrial URFA6L gene consists of 165 base pairs. The overall structural organization of the gene is very similar to that of the Xenopus URFA6L gene. Their nucleotide sequences exhibit 68% homology. The carp URFA6L gene encodes a protein of 54 amino acids. The amino acid composition of the protein is unusual because almost half of the residues consist of 5 hydrophobic amino acids(proline, tryptophan, leueine, isoleueine and tyrosine). A comparison between the amino acid sequences of 5 vertebrate URFA6L proteins and the yeast ATPase8 showed that they have weak but very important common structural features, suggesting that the vertebrate URFA6L proteins may function asATPase8. The nucleotide sequence of the lysine tRNA gene from carp has been determined and represented in cloverleaf secondary structure. Similar to amphibian and mammalian mitochondrial tRNA~(Lys) genes, the carp mitochondrial tRNA~(Tys) gene also has some unusual structural features as compared with its cytoplasmic counterpart  相似文献   

19.
目的:为了解宁波地区淡水养殖鱼PAEs污染情况。方法采用液液超声萃取-气质联用法对宁波6个不同养殖点5种淡水养殖鱼体内8种邻苯二甲酸酯含量进行分析。结果宁波地区养殖鱼主要受 DMP、 DEP、 DBP、 DEHP 和 DOP 污染,质量分数最高可达134.1、258.9、249.2、830.8和5029μg/kg;草鱼、鳊鱼、鳙鱼、鲫鱼和乌鳢邻苯二甲酸污染指数PPI分别为9.999、9.735、13.97、8.945和5.809μg/kg。结论宁波地区淡水养殖鱼鱼体邻苯二甲酸酯含量与养殖环境有关,与鱼种无关。  相似文献   

20.
THE CRYSTAL STRUCTURE OF SILVER CARP INSULIN AT MEDIUM RESOLUTION   总被引:1,自引:0,他引:1  
It is an important way of surveying the structure-functionrelationship of insulin tostudy insulins from different species. Based on the structure model of an orthorhombic crys-tal obtained by the molecular replacement method, the crystallographic refinement of a hex-amer of silver carp insulin in an asymmetric unit has been carried out with 2.8A resolutiondata using the restrained least- squares method. The comparisons of insulin structures haveshown that the six silver carp insulin molecules have very similar but not identical three- di-mensional structures which are similar to the known 2Zn pig insulin structure but remarka-bly different in some local conformations.  相似文献   

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