珍珠层粉制取现状

科学研究证明珍珠层粉和珍珠粉物质组成和含量非常接近,如果能够制得纯正的珍珠层粉,那么就能应用在化妆品、保健品领域。本文详细介绍了珍珠层粉的几种制备方法的优缺点,提出了采取碱法制备珍珠层粉,优化工艺,制备纯正珍珠层粉的想法。     

可溶性珍珠粉制备工艺的研究

可溶性珍珠粉以珍珠为原料，经粉碎，酶水解后再活化，最后干燥精制而成。它能更充分发挥珍珠的药用功效。     

临浬县合口珍珠场简介

临浬县合口珍珠场是新兴的乡镇企业,建立了从孵化幼蚌到珍珠项链、珍珠粉加工的一条龙生产体系。从1980年开始养殖珍珠,产量产值不断上升,1987年产珠210公斤,全场利润30万元,1988年他们计划生产珍珠800公     

淡水无核珍珠荧光光谱的研究↑（*）

对三角帆蚌珍珠、贝壳珍珠层及商品珍珠粉等进行了固体表面荧光测定。荧光图谱显示：在２８０ｎｍ激发波长下,３种样品都具有３４５ｎｍ和４６５ｎｍ的特征荧光峰,且３４５ｎｍ处荧光强度最大,并伴有荧光淬灭现象。这说明珍珠及其贝壳中含有色氨酸（Ｔｒｐ）。用５ｍｍｏｌ／ＬＢａ（ＯＨ）２碱法水解处理从珍珠及其贝壳中提取的壳角蛋白,测得水解液的内源荧光光谱和其中Ｔｒｐ的含量为００４％～００７％。     

淡水珍珠层粉的制取及药用研究

无产阶级文化大革命以来，在毛主席的无产阶级革命路线指引下，我们遵照．毛主席关于“把医疗卫生工作的重点放到农村去”和“备战、备荒、为人民”的教导，三年来，学习了广东澳头珍珠养殖场及广州市中药五厂利用马氏珍珠贝生产珍珠层粉的经验，利用淡水珍珠贝壳生产珍珠层粉代替珍珠粉供药用。并经有关部门化验，认为质量符合药检标准，成份亦与珍珠相似。在临床试验中，已取得了良好效果，获得了广大工农兵的欢迎和好评。     

外套膜上皮细胞与组织块的离体珍珠囊形成试验

通过对三角帆蚌外套膜上皮组织块培养和上皮细胞培养存包硬核、无包硬核的情况下的钙代谢进行比较分析,用偏光显微镜观察.结果发现,外套膜上皮组织块、上皮细胞在有硬核时与埘照的无硬核培养钙含量无明显差别,外套膜组织块经培养迁移和增值,能形成珍珠囊的上皮细胞,其结缔组织细胞共同围绕珍珠囊上皮细胞组成完整的珍珠囊.偏光显微镜下能观察到舣折射现象,表明产生由碳酸钙结晶形成的片层叠加构成珍珠质.该研究进一步探讨了体外培育珍珠(试管珍珠)的技术,为试管珍珠的研究提供了实验依据.     

三角帆蚌珍珠囊细胞的分泌活动

本文对三角帆蚌珍珠囊细胞的分泌活动进行了亚显微结构的研究。发现珍珠囊表皮细胞能积极地进行物质合成 ,这些物质主要是蛋白质、硫酸化粘多糖和中性粘多糖 ,并将这些物质以微绒毛分泌、块状物分泌、细胞间隙分泌和大颗粒分泌等多种方式分泌到珍珠囊腔 ;而位于珍珠囊表皮细胞之间的、来源于外套膜结缔组织的腺细胞则含有丰富的中性粘多糖 ,并通过开口式分泌的方式释放到珍珠囊腔 ,同珍珠囊表皮细胞分泌的物质一起 ,共同参与珍珠结晶层的形成 ;珍珠囊细胞分泌的多样性与珍珠组成的复杂有关 ;珍珠囊细胞的分泌活动具有节律性和区段性的特点 ,这种区段性和节律性的分泌与珍珠多层结晶纤层的形成相适应。     

淡水珍珠养殖业的现状及对策

珍珠历来被视为珍宝，又是名贵的中药材，珍珠粉为原料配制的各种化妆品和保健品，深受广大消费者欢迎。我国淡水珍珠生产出口目前仍居世界第一位，１９９８底淡水珍珠养殖业又呈火爆场面，但珠供过于求的形势并没有发生根本变化，要冷静分析，引导群众生产，使淡水珍珠养殖业走向健康的可持续发展的道路。１历史与现状 建国５０年来，我国珍珠养殖飞速发展，特别是改革开放２０年中，养殖产量成倍增长。７０年代中后期，珍珠市场价格大幅度回升，育珠蚌的人工繁殖已经突破，我国的淡水珍珠产量，特别是褶纹冠蚌珍珠产量上升很快，至１９８…     

突破质量 提升品位 常德市珍珠产业化工程高位启动

本刊讯2003年2月27日,常德市政府召开了珍珠产业化工作会议,这次会议是市委、市政府决定把珍珠业作为该市农业经济发展的一个重要支柱产业之后召开的第一次工作会议,市有关领导、区县(市)主管领导、畜牧水产局局长、洞庭水殖、市农产品(珍珠)大市场、珍珠协会理事和部分珍珠养殖大户参加会议。会议总结了近几年来发展珍珠的经验教训,分析国内外珍珠市场形势,研究实现珍珠产业化的路子和措施。世界珍珠协会主席何乃华先生和省畜牧水产局副局长王宇到会并作了指导性讲话。近几年常德市珍珠养殖业取得一定成绩。2002年育珠面积达1.22万公顷,比…     

三苯基锡对褐菖鲉脑雌激素受体和视黄酸X受体表达的影响(英文)

尽管三苯基锡(triphenyltin,TPT)能够影响鱼类生殖功能以及性腺的发育,但其作用机制并不十分清楚。由于鱼脑在生殖调控中具有重要作用,本研究以海洋鱼类褐菖鲉(Sebastiscus marmoratus)为研究对象,研究TPT对脑中芳香化酶(Cyp19b)、雌激素受体(ERα和ERβ)、视黄酸X受体α(RXRα)和过氧化物酶体增殖物激活受体(PPARγ)基因表达的影响。暴露48 d后,TPT对雌性和雄性褐菖鲉脑中Cyp19b和PPARγ的表达均未产生显著性影响。TPT诱导了雄性褐菖鲉脑中ERα的表达并抑制了ERβ的表达;尽管TPT也抑制雌性褐菖鲉脑中ERβ的表达,但对ERα的表达却未产生显著性影响。另外,TPT诱导了雄性褐菖鲉脑中RXRα的表达,而在雌鱼脑中却产生了相反的作用,抑制了RXRα的表达。因此,TPT对褐菖鲉脑中ER和RXR表达的影响可能具有性别差异性,表明TPT具有复杂的内分泌干扰效应。另外,结果表明,TPT可能通过干扰鱼脑ER和RXR产生生殖毒性。     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.     

Influence of the antibacterial herbs, Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia on the survival, growth and bacterial load of Penaeus monodon post larvae

The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 10³ to 3.76 × 10⁵ cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 10⁵ cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.