Localization of nitric oxide synthase in the developing gonads of amphioxus Branchiostoma belcheri tsingtauense

The localization of nitric oxide synthases （NOS） is dealed with in the developing gonads of amphioxus Branchiostoma belcheri tsingtauense. It was found by NADPH-diaphorase staining that （1） NOS activity was present in the nuclear membranes of germinal vesicles during the entire period ofoocyte development; （2） NOS was localized in both the nuclear membranes and the perinuclear region of cytoplasm in the vitellogenetic oocytes; （3） NOS was relocated in the cortical layer in the mature egg; （4） NOS activity was present in spermatocytes, but not in the spermatogonia in the middle of October; （5） NOS was detected in both spermatozoa and spermatids as well as spermatocytes during the breeding season. This is the first report on the distribution pattern of NOS in the developing gonads in protochordates. These results suggest a role for NOS in the functioning of the nuclear membranes and yolk synthesis during oogenesis and in cell division and differentiation during spermatogenesis.     

Studies on rickettsia-like organism(RLO)disease of tropical marine pearl oyster--Epidemiologicai investigation of RLO disease in juvenile populations of maricultured Pinctada maxima

The death which occurred in juvenile population was a severe problem in the course ofPinctada maxima artificial culture. With the methods of field investigation, histological study andstatistic analyses, the epidemiological study was carried out on the disease and death in juvenile popula-tions of Pinctada maxima in the Xinying Pearl Oyster Mariculture Farm of Lingao County (for the A,B and C batches of cultured juveniles hanged in the sea) and the Xincun Pearl Oyster Mariculture Farmof Lingshui County (for the D batch of cultured juvenile hanged in the pond), Hainan Province fromNovember 1993 to April 1995. The results show that the deaths which occurred in juvenile populations of Pinctada maxima pre-sented an outbreak pattern. The peak of mortality rates, in general, occurred in 4-to 6-month old pearloyster juveniles, and the mortality rates gradully declined with the extention of pearl oyster age after cul-turing 8 months. The correlation between the mortality rates of juvenile populations and mean bodylengths of juvenile populations show that the mortality rate become higher under 4 cm of mean bodylengths of juvenile population and become obvious declined over 5 cm of mean body lengths. The peak ofmortality rate occurred in 1 ～3 cm of mean body lengths. The results of histological observation showedthat rickettsia-like organism inclusions were common, histological widespread infective agent among ev-ery batches (A, B, C and D) of cultured juvenile populations. The mean severity indices (SI) of rick-ettsia-like organism (RLO) infection were positively correlated with mortality rates of juvenile popula-tions. After or within every peaks of RLO infection were all accompanied with the peaks of mortalityrates of host populations and the mortality rates declined with decreased RLO infection. So the evidencesof histological observation and epidemiology in this study indicated that rickettsia-like organism (RLO)may be as an important pathogenic organism of disease and death of cultured Pinctada maxima. In addi-tion, a few ciliates were discovered only in part of batch A of cultured juvenile population. The mortalityrates in juvenile populations were not correlated with the weekly mean temperature and salinity of seawater.     

Studies on rickettsia-like organism (RLO) disease of tropical marine pearl oyster——Epidemiological investigation of RLO disease in larvae populations of maricultured Pinctada maxima

The onset and sPread of diseases in dricultured Anrnals are resulted frOm the mutule ef-fect of pathogen, hOSt and environrnnt. Epidemology takes the diseased AnInal poPulationsas the study object, rnakes observation and exPeriment on the field as the primp method ofstUdy and stuha the mutule effec Of PathOgen, hOS and environrnen by inVeSigating the na-ttire distribution of diseases and ePidendc mechedsm. To date, succeSSful exarnple of epidend-obo study on lerne shellfish deseases is…     

Studies on rickettsia-like organism (RLO) disease of tropical marine pearl oyster-Epidemiological investigation of RLO disease in juvenile populations of maricultured Pinctada maxima

The death which occurred in juvenile population was a severe problem in the course ofPinctada maxima artificial culture. With the methods of field investigation, histological study and statistic analyses, the epidemiological study was carried out on the disease and death in juvenile populations of Pinctada maxima in the Xinying Pearl Oyster Mariculture Farm of Lingao County (for the A, B and C batches of cultured juveniles hanged in the sea) and the Xincun Pearl Oyster Mariculture Farm of Lingshui County (for the D batch of cultured juvenile hanged in the pond), Hainan Province from November 1993 to April 1995.The results show that the deaths which occurred in juvenile populations of Pinctada maxima presented an outbreak pattern. The peak of mortality rates, in general, occurred in 4-to 6-month old pearl oyster juveniles, and the mortality rates gradully declined with the extention of pearl oyster age after cul-turing 8 months. The correlation between the mortality rates of juvenile populations and mean     

热带海洋珍珠贝类立克次体(RLO)病研究 Ⅷ.养殖大珠母贝贝苗养成期群体RLO病流行病学研究

大珠母贝人工养殖过程中,幼贝死亡是一个严重的问题。1993年11月至1995年5月,采用现场调查、实验室研究和数理分析相结合的方法,在海南省临高县新盈珍珠贝养殖场自然海区吊养的A,B,C3批养殖贝和陵水新村珍珠贝养殖场养殖池吊养的D批养殖贝的发病和死亡情况进行了流行病学凋查.结果显示,大珠母贝幼贝群体的死亡是以暴发性方式发生,幼贝群体的大批量死亡高峰一般发生在4～6月龄期,8个月以后随着龄期的延长,死亡率显著降低.幼贝群体死亡率与贝体平均体长的关系是4cm以下的贝体死亡率较高,1～3cm阶段处于死亡高峰期内,5cm以上的贝体死亡率显著降低.大珠母贝幼贝群体的死亡率与类立克次体感染(即RLO平均感染严重度指数SI)之间存在显著的相关性,在RLO感染的高峰之后或当中部相应伴随贝群体死亡率的高峰,随着RLO感染的降低,贝群体的死亡率也明显降低。在4批养殖贝群体中,仅在A批养殖贝群体样本中发现有少量纤毛虫寄生(感染率为87.5%,感染强度为3.56个/10倍物镜).这几批幼贝群体的死亡与海水温度、盐度之间均无相关性。     

副溶血弧菌、脂多糖和嗜酸小球菌对凡纳滨对虾血清一氧化氮合酶的影响

探讨了凡纳滨对虾Litopenaeus vannamei血细胞中是否存在一氧化氮合酶(NOS)活性,进行了副溶血弧菌Vibrioparahaemolyticus和哈维氏弧菌Vibrioharveyi脂多糖(LPS)体外孵育实验,采用亚硝酸盐法对凡纳滨对虾血细胞中NOS活性进行了测定。结果表明,副溶血弧菌和LPS离体孵育血细胞组的一氧化氮(NO)浓度显著高于对照组,而且这一反应能被NOS抑制剂亚硝基L精氨酸甲酯(LNAME)所阻断,证实了凡纳滨对虾血细胞中存在NOS活性。同时进行了副溶血弧菌感染凡纳滨对虾对其血清NO浓度和NOS活性的影响试验。试验表明,副溶血弧菌注射感染凡纳滨对虾后12h血清中NOS活性极显著高于对照组;NO浓度在注射后24h开始升高,72h后各组NO浓度都显著高于对照组。说明副溶血弧菌感染凡纳滨对虾可以诱导NOS的表达,并产生NO来抵抗副溶血弧菌的入侵,从而增强了对虾的免疫力。此外将嗜酸小球菌Pediococcusacidilactici按10.0mg·kg-1添加到饲料里投喂凡纳滨对虾后,血清中溶菌酶活力和NOS活性比对照组有显著提高,且溶菌酶活力和NOS活性存在显著正相关性(r=0.629,r0.05[1,12]=0.532)。从而进一步说明了NOS活性可以作为凡纳滨对虾免疫力高低的有效指标。     

海水中-氧化氮的化学发光法测定

基于鲁米诺-H2O2混合溶液作为发光液与海水中NO发生反应产生发光信号的原理,提出了一种测定海水中痕量NO的化学发光法.确定了化学发光法测定NO的最佳条件:pH9.2、浓度1×10-2 mol/dm3的碳酸盐为缓冲体系,鲁米诺浓度为8.4×10-5 mol/dm3,H2O2浓度为1×10-2 mol/dm3,测定温度为...     

活性铁对海洋沉积物中有机碳的保存作用

沉积物碳汇是海洋碳汇的重要组成部分,揭示沉积物的储碳机制对研究气候变化与全球碳循环的相互作用具有重要意义。矿物对有机碳的保护作用是有机碳最重要的稳定机制,其中活性铁（FeR）在沉积物有机碳的累积作用中发挥着捕获有机碳并形成“铁锈碳汇”的重要作用。本文系统梳理了近年来关于海洋沉积物中FeR的固碳的研究成果,总结了海洋沉积物中FeR的提取方式、类型、固碳量、固碳机制、结合有机质来源及分子类型,阐述了FeR固碳的重要意义,旨在加深对矿物与有机碳相互作用的理解。海洋沉积物中FeR常通过柠檬酸盐 碳酸氢盐 连二亚硫酸盐(CBD)还原提取,主要以针铁矿、水铁矿及赤铁矿等氧化物形式存在。FeR可以结合沉积物中约80%的有机碳,结合机制包括以配体交换为主的吸附机制和共沉淀/螯合机制。FeR与有机碳的结合机制可依据铁结合有机碳（FeR OC）与FeR的摩尔比值（FeR OC∶FeR）简单判定,当FeR OC∶FeR低于1.00时以吸附方式结合,大于1.00时以共沉淀方式结合,且共沉淀相比吸附机制具有更高的有机碳结合量及稳定性。大部分海洋沉积物中FeR优先与海源类有机质结合,但在氧化还原频繁的河口及三角洲地区倾向与陆源类有机质结合。分子模拟实验、木质素氧化降解及近边X射线吸收精细结构光谱表明FeR与芳香碳及羧基碳等有机质具有更高的亲和性。FeR对有机质的稳定保存及减缓气候变化引起的负反馈具有重要意义,建议未来更多关注沉积物中有机质与铁矿物结合的具体过程及不同沉积环境FeR固碳的差异机制,更加关注不同结合机制的定量化及重要性对比研究。     

Mutual effects of nitric oxide and iron on the growth of marine algae

Experiments on the effects of nitric oxide （NO） and iron on the growth of marine microalgae Skeletonema costatum were conducted. The results are as follows： exogenous NO could increase the growth rate of marine algae and raise the biomass remarkably under iron-deficient conditions. But it was a complicated process that the phytoplankton growth was influenced by NO and iron, which was controlled by the NO concentration, the nutrition level of the culture medium and the iron concentration, etc. Meanwhile, the iron concentration in the medium also has a direct influence on the growth and NO release capacity of the algae. Therefore, the effects of NO and iron on the growth of marine phytoplankton were mutual.