叶绿素a测定方法之比较

本文比较了3种滤膜（玻璃纤维滤膜、醋酸纤维滤膜、微孔滤膜）、不同提取时间和不同离心温度对叶绿素a含量测定的影响。结果表明，玻璃纤维滤膜叶绿素a测定值显著高于醋酸纤维滤膜和微孔滤膜；叶绿素a最佳提取时间在16h-24h；放人冰块制冷所测得的叶绿素a含量显著高于不放入冰块制冷的含量。     

尼罗罗非鱼(Oreochromis niloticus)cyp19a1a原核表达与蛋白纯化

为表达和纯化尼罗罗非鱼(Oreochromis niloticus)cyp19a1a蛋白,本研究从尼罗罗非鱼卵巢提取总RNA,反转录获得cDNA模板后,利用设计的引物PCR扩增cyp19a1a ORF区1200 bp片段,双酶切后连接到pET-28a(+)表达载体上,经酶切验证和DNA测序鉴定,证明成功构建了pET-28a-cyp19a1a原核表达载体。将表达载体转化到大肠杆菌(E.coli)BL21中,优化IPTG诱导浓度和诱导时间。结果显示,在0.5 mmol/L IPTG诱导8 h后,cyp19a1a重组蛋白大量表达,并以包涵体形式存在。通过Ni2+-NTA层析柱和切胶纯化,获得与预期片段大小一致的表达蛋白,并用Western blotting验证了纯化的蛋白为目的蛋白。本研究为制备cyp19a1a抗体和研究高温对cyp19a1a蛋白表达的影响提供了重要的基础。     

Start-up performance of a woodchip bioreactor operated end-of-pipe at a commercial fish farm—A case study

There is a need for simple, maintenance-free technologies for removing nitrogen (N) from aquaculture effluents. Denitrifying woodchip bioreactors have been used successfully to remove nitrate-N (NO₃-N) from ground and surface waters and may potentially be applied to dilute aquaculture effluents as well. Real-life applicability in commercial, outdoor fish farms including practical start-up issues such as e.g. time till stable performance and potential leaching are, however, unknown to the industry.This case study consequently investigated the temporal performance of a woodchip bioreactor (12.5 m³) during start-up. The bioreactor was operated end-of-pipe at a commercial, outdoor rainbow trout (Oncorhynchus mykiss) farm in Denmark operated at low recirculation intensity. Applying an empty bed contact time (EBCT) of 5 h, the specific objectives of the study were to resolve: i) how fast the bioreactor would start to remove NO₃-N; ii) how fast steady state was achieved; iii) which NO₃-N removal rates could be attained at the relatively low effluent temperature (∼8 °C) and iv) to which extent any concomitant leaching of phosphorous (P), ammonia or organic matter would occur.In- and outlet grab samples were obtained every 6 h until the bioreactor was in steady state (2 weeks) followed by weekly 24 h pooled samples for another 3 weeks (5 weeks in total). Additional grab samples were obtained from 9 sampling ports within the bioreactor on 3 consecutive days during steady state. Samples were analyzed for dissolved nutrients (total N, nitrate, nitrite, ammonium, total phosphorous, ortho-phosphorous, BOD₅ and COD). In addition, oxygen, temperature and pH were logged every 30 min while sampling and alkalinity were measured once a week.Removal of NO₃-N started immediately and remained stable at 7.06 ± 0.81 g NO₃-N/m³/d (n = 6) throughout the sampling period. Increased effluent NO₂-N concentrations (peaking at 1.14 mg NO₂-N/l after 4–5 days) were transiently observed during the initial 11 days. After that, the woodchip bioreactor was largely in steady state with respect to N-balances corroborated by a close match between filtered total-N (TN_diss) and NO₃-N removal rates. Measurements within the bed showed that the majority of the influent dissolved oxygen (DO) was consumed within the first part of the bioreactor and that NO₃-N removal thereafter proceeded gradually with distance within the bed. Leaching of non-structural, dissolved organic compounds were observed just after startup, causing a short-term (1 week) increase in effluent concentrations of COD, BOD₅, P and ammonium.Additional measurements carried out until 147 days after start-up showed that the woodchip bioreactor continued to remove TN_diss at an average removal rate of 7.81 ± 0.82 g N/m³/d, and that the initial leakage of P stopped altogether.In summary, the study demonstrated that woodchip bioreactors can effectively remove NO₃-N from dilute aquacultural effluents at low temperatures and commercial conditions and that stable performance is achieved within a few weeks.     

KYW 35a环模制粒机研制报告

KYW35a环模制粒机是在80年代消化吸收丹麦制粒机的基础上研制成功的。本文着重介绍了此机改进后与原引进机的7大技术不同点,并对其技术优劣进行了简要的论证。     

大伙房水库叶绿素a的周年分布

本文根据１９９１年大伙房水库叶绿素ａ的调查资料，阐述了水域中绿素ａ的周年分布，并分析了各种生态因子与叶绿素ａ之间的关系，为发展水库渔业和环境评价提供了参考依据。     

犬a干扰素的基因工程研究进展

干扰素是由脊椎动物细胞产生的一类分泌型蛋白,是由"干扰素诱生剂"诱使动物机体有关细胞所产生的一类特殊"糖蛋白"。这类糖蛋白从其产生细胞产生和释放出来后,又可作用于动物机体的同种其他细胞,并使这些细胞获得相当广泛的"免疫力",具有广谱抗病毒、抗肿瘤、抑制细胞增殖以及提高免疫功能等作用。干扰素可与细     

Profiles of sex steroids, fecundity and spawning of a migratory characiform fish from the Paraguay–Paraná basin: a comparative study in a three-river system

This study investigated for the first time the reproductive biology of Prochilodus lineatus in a system of rivers in southeastern Brasil, relating it to the role of tributary rivers in the reproductive success of this important commercial fish in the Upper Paraná River basin, where a cascade of hydroelectric dams were deployed. Specimens were caught bimonthly in three river sites: (S1) Grande River, downstream from the Porto Colômbia dam; (S2) Pardo River; and (S3) Mogi Guaçu River. Sex steroid plasma levels, fecundity, follicular atresia, oocyte diameter and gonadosomatic index (GSI) were compared among sites. In S1, fish exhibited changes in the reproductive parameters: lower GSI, oocyte diameter and fecundity and higher follicular atresia index, when compared to S2 and S3. Frequency of maturing fish was higher in S3 and spawning was only registered in S3. In sites S2 and S3, plasma concentrations of testosterone and 17β-estradiol in females and testosterone in males showed wide variations following gonadal maturation. Fish from S1 showed few significant variations in sex steroid concentrations throughout the gonadal cycle. These results indicate that P. lineatus does not reproduce in Grande River (S1), but probably uses the Pardo River (S2) as a migratory route towards the Mogi Guaçu River (S3) where they complete gonadal maturation and spawning. Our findings contribute for understanding the reproductive biology of P. lineatus and to highlight the importance of tributaries in impounded rivers as a favourable environment for migration and spawning of fish.     

尼罗罗非鱼(Oreochromis niloticus) cyp19a1a原核表达与蛋白纯化

为表达和纯化尼罗罗非鱼(Oreochromis niloticus)cyp19a1a蛋白,本研究从尼罗罗非鱼卵巢提取总RNA,反转录获得cDNA模板后,利用设计的引物PCR扩增cyp19a1a ORF区1200 bp片段,双酶切后连接到pET-28a(+)表达载体上,经酶切验证和DNA测序鉴定,证明成功构建了pET-28a-cyp19a1a原核表达载体。将表达载体转化到大肠杆菌(E.coli)BL21中,优化IPTG诱导浓度和诱导时间。结果显示,在0.5 mmol/L IPTG诱导8 h后,cyp19a1a重组蛋白大量表达,并以包涵体形式存在。通过Ni2+-NTA层析柱和切胶纯化,获得与预期片段大小一致的表达蛋白,并用Western blotting验证了纯化的蛋白为目的蛋白。本研究为制备cyp19a1a抗体和研究高温对cyp19a1a蛋白表达的影响提供了重要的基础。     

Short-Term Dinoflagellate Bloom in a Shrimp Pond in Bahía de La Paz,Gulf of California

From mid-August to mid-September 1998, a dinoflagellate bloom in a shrimp pond near La Paz, Baja California Sur, was studied. Daily samples were taken of phytoplankton, dissolved oxygen, nutrient concentrations, photosynthetic pigments and proteins. The bloom occurred at temperatures of 29.7 to 33.2?°C. High densities of a Scrippsiella-like dinoflagellate (15.9?×?10⁶ cells/L) occurred on the first day of sampling, reaching a peak of 249?×?10⁶ cells/L on Day 13, and declining to 4 to 7?×?10⁶ cells/L by Day 26. Chlorophyll a varied from 8.63 mg/m³ on Day 4 to 141.38 mg/m³ on Day 13. Total nitrogen varied widely (0.2–11.50 μM) while phosphates peaked only once on Day 13 (4.14 μM). Proteins ranged from 523 to 6387 μg/L; the latter value occurred two days after the maximal peak of nitrates and coinciding with the highest level of phosphates. Fertilizers added to the ponds increased nutrient concentration and stimulated phytoplankton growth. In turn, the food supply to cultured shrimp noticeably increased throughout the bloom.     

长江口外水域叶绿素a分布的基本特征

本文根据１９８８年８月、１２月、８９年８月和１９９１年９月对长江口外附近水域进行的多学科的综合调查结果，着重探讨长江河口羽状锋区附近叶绿素ａ含量的分布特征及其与海洋环境因子的关系。调查海区叶绿素ａ含量从长江口外向东构成低、高、最低的分布趋势，夏季形成向东或东北扩展的、清晰可辨的叶绿素ａ的羽状锋。     

卫星遥感北太平洋渔场叶绿素a浓度

海洋叶绿素a(Chla.)含量是了解世界海洋中地球生物化学循环的基础和估算海洋生产力的基本指标,是判断水域的肥瘠程度和评价水域渔业潜在生产力的基本依据。富集浮游植物的海域是海洋食植动物的大密度存在和水产资源丰富存在的基础,许多鱼类如金枪鱼等中上层鱼群集在锋面两侧或涡旋,这些特征与营养盐供给或混合层深度变化相关。北太平洋渔场已成为我国远洋渔业的重要组成部分,卫星遥感技术可以实现大面积同步的观测和一年四季连续的观测,是测定北太平洋渔场海洋叶绿素a的最有效方法。1 材料和方法1.1 数据来源卫星资料采用美国海洋水色卫星的宽视场海洋水色扫描仪(SeaWiFS)资料,全球海上测量资料利用国际海洋水色协调工作组(IOCCG)在世界大洋范围测量的1175个站位光谱数据和对应的叶绿素a浓度,南海测量数据由国家海洋技术中心在南海测量的48个站位光谱数据和叶绿     

Marteiliosis in mussels: a rare disease?

Among 1280 cultured and wild adult Mediterranean mussels, Mytilus galloprovincialis, collected over a 1 ‐ year surveillance period from the Slovene Adriatic Sea, 0.3% were histologically positive for the presence of Marteilia spp. The infection was concentrated in winter. Employing the molecular methods of PCR, cloning, DNA restriction and sequencing, only Marteilia refringens type M was detected in all the infected mussels. Although all life‐cycle stages of M. refringens severely infected digestive glands, only sporadic disruption of epithelial cells of digestive tubules and focal destruction of digestive tubules were observed in the infected mussels. This was the first detection of M. refringens in M. galloprovincialis from the Slovene Adriatic Sea with the lowest prevalence reported to date. In addition, our results highlight the need for sequencing to complement the established PCR‐RFLP analysis for correct parasite typing.     

海州湾叶绿素a与水环境因子的多元分析

叶绿素a作为水环境质量的重要指标,对水体理化性质具有指示作用。对江苏海州湾叶绿素a时空分布特征进行分析,发现叶绿素a随距陆远近而发生变化,受陆源输入影响较重,同时当地的富营养化程度在夏秋季节较高。经过水环境因子聚类和相关性分析,得到影响叶绿素a的有效因子,在此基础上进行多元线性回归分析,提取出了主要因子为pH值和水温。     

不同倍性鲫鲤性腺型芳香化酶cyp19a1a基因cDNA的克隆及表达

为研究性腺型芳香化酶P450aromA(cyp19a1a基因编码)在不同倍性鲫鲤卵巢发育过程中的作用,实验采用同源克隆和cDNA末端快速扩增技术(RACE),获得了二倍体红鲫、三倍体湘云鲫和四倍体鲫鲤的cyp19a1a基因cDNA全长。结果显示,3种鱼cyp19a1a基因均编码517个氨基酸残基,而且编码的蛋白都包含P450aromA特有的跨膜螺旋区、I-螺旋区、Ozol’s肽区、芳香化酶特异保守区以及血红素结合区。采用RT-PCR分析cyp19a1a基因mRNA在3种不同倍性鱼类组织中的表达情况,结果显示,cyp19a1a基因主要在实验鱼的卵巢中表达,其次在精巢、脑、脾脏有少量表达。采用实时荧光定量PCR对cyp19a1a基因mRNA在不同倍性鱼卵巢中的表达进行分析,结果发现,cyp19a1a基因在不同倍性鱼的非繁殖期卵巢的表达都高于繁殖期卵巢,并且在繁殖期和非繁殖期,cyp19a1a基因在三倍体湘云鲫的表达量高于二倍体红鲫和四倍体鲫鲤。采用免疫组织化学方法对CYP19A蛋白在不同倍性鲫鲤卵巢中的定位进行分析,结果发现,CYP19A蛋白主要定位在滤泡细胞、Ⅳ时相卵母细胞的放射膜上以及Ⅱ时相卵母细胞的卵浆中。研究表明,性腺型芳香化酶在不同倍性鲫鲤卵巢发育过程中的表达存在一定的差异性,三倍体鱼cyp19a1a基因mRNA水平表达异常,推测与其不育有关联性。     

平潭海坛湾叶绿素a的分布特征

根据2013年6月(春季)和11月(秋季)平潭海坛湾的调查数据,研究了海坛湾叶绿素a的分布特征及其与环境生物因子的相关关系。结果表明,海坛湾春、秋季叶绿素a平均含量分别为3.1 mg/m3和1.1 mg/m3,春季叶绿素a含量呈现从内湾向湾口方向逐渐减小的趋势,秋季略呈湾外侧高于内侧的趋势。春季海坛湾叶绿素a含量高于福建省北部海湾和台湾海峡等历史水平,秋季水平相当。春季叶绿素a含量与盐度、营养盐和浮游动物密度相关,秋季与悬浮物质含量相关。     

隔河岩水库浮游植物叶绿素a周年变动及评价

1999年7月至2000年7逐月测定隔河岩水库上下游共5个站的叶绿素a含量,全库年均2.55μg/L.除上游桃山站在2000年4月、5月出现高值6.00μg/L和11.25μg/L的特异性变化,其余各月均在0.72～4.48μg/L.各站年均在2.00～3.18μg/L,以上游桃山及下游临坝沿市口站最高.年变化受气候和水位升降综合作用,有5月、6月、9月及2月4个峰值.叶绿素a含量的垂直分布表明水流运动复杂.据OECD及美国FPA标准将隔河岩水库定为贫营养型.     

花鲈性腺分化组织学及性别相关基因cyp11b和cyp19a1a的表达分析

以花鲈(Lateolabrax maculatus) 1~214 dph (day post hatching)的仔稚鱼、幼鱼以及18月龄的雌鱼和雄鱼为研究对象,研究了花鲈早期性腺发生、发育和分化情况;分析了性腺分化过程中性别相关基因(cyp11b和cyp19a1a)的表达及与性别之间的关系。结果显示,在30 dph [全长为(1.28± 0.10) cm],首次在中肾管前端的腹腔膜周围观察到原始生殖细胞(primordial germ cells, PGCs),说明30 dph前是花鲈胚后PGCs迁移至生殖嵴的关键时期;在55 dph [全长为(2.45±0.19) cm],观察到一对呈对称分布的原始性腺已经形成,说明花鲈幼鱼的原始性腺在30~55 dph (全长为1.28~2.45 cm)之间发生;55~180 dph时(全长为2.45~12.28 cm),原始性腺不断发育变大,并且一直处于未分化状态;180 dph后性腺开始分化;在195 dph [全长(14.54±1.54) cm]观察到精巢开始分化,卵巢于205 dph [全长为(15.86±0.94) cm]开始分化,且性腺的解剖学分化要早于细胞学分化;18月龄的花鲈幼鱼性腺发育到Ⅱ期。性别分化相关基因cyp19a1a在花鲈卵巢中的表达量高于同期精巢,说明其在卵巢的分化及维持中发挥更关键的作用,而cyp11b在18月龄幼鱼Ⅱ期精巢中的表达量显著高于同时期的卵巢及Ⅰ期精巢,说明其主要在精巢的分化及维持中扮演重要角色。本研究结果不仅可以丰富花鲈的繁殖生理学资料,也为其性别调控技术的研究提供了科学依据。