滇池试验围隔内不同形态铁浓度的变化与物化因子的关系

在蓝藻水华形成以后,通过围隔实验,从2003年6月份到10月份定期采样测定水体中的pH、溶解氧(DO)、水温、总铁、亚铁、过滤性铁(<0.45μm)和可溶性磷的浓度,研究物化因子对不同形态铁浓度变化的影响。实验结果表明,蓝藻水华优势种微囊藻在pH 7—9和水温17.5—20.5℃的条件下,生长旺盛,消耗了大量的亚铁,使亚铁浓度大幅度下降;溶解氧和磷酸盐对亚铁浓度没有显著影响;在水华蓝藻严重发生的条件下,水体中的总铁和过滤性铁浓度没有显著意义的变化,而亚铁浓度的变化与水华蓝藻的种群密度成显著负相关(r=-0

快速建立鲢、鳙纯系的初步研究

运用随机扩增多态性DNA(RAPD)方法对雌核发育和人工转性鲢、鳙进行了遗传多样性的研究,并用长江天然鲢、鳙群体作为对照分析.在雌核发育鲢中,共得到187条带,其中19条为多态带,占10.16％,而对照组鲢共扩增205条带,有32个多态座位,占总带数的15.61％.在雌核发育鳙中共产生232条带,其中11条为多态带,比例为4.74％,而在对照组中共产生241条带,25条为多态带,比例为10.37％.遗传距离分析表明,雌核发育鲢和鳙的平均值分别为0.102和0.023.而对照组鲢和鳙遗传距离平均值分别为0.

铜锈微囊藻两种表型的生长生理特性及毒素组成比较分析

从滇池蓝藻水华中分离得到的铜锈微囊藻群体在实验室无机营养中解聚成单细胞 ,结果表明 ,群体微囊藻的生长速度明显低于单细胞微囊藻 ;前者具明显可见的胞外酸性多糖胶鞘 ,而单细胞则几乎没有 ;按常规方法分析比较两种细胞形态的毒性大小和毒素组成 ,发现群体微囊藻主要含有三种微囊藻毒素的异构体 ,而单细胞以MC LR为主 ;且单细胞微囊藻的毒性约为群体的 1 0倍。二者的LDH和PGM同工酶酶谱也有差异。本研究为解释毒素的合成和调控机理提供了新的证据

念珠藻葛仙米叶绿素荧光与水分胁迫的关系

在渗透系统中 ,念珠藻葛仙米因轻微失水而叶绿素的Fv/Fm 上升 ;水势继续降低时Fv/Fm快速下降。衬质系统和自然失水的影响相似 ,藻体在失去总水分的 94 %以后Fv/Fm 开始下降 ,此前水分的丢失对Fv/Fm 比值的上升稍有促进作用。干燥藻体吸水后Fv/Fm 的恢复速率随着贮藏时间的延长而下降 ,并且Fv/Fm 的恢复对光和蛋白质的重新合成有依赖性。DCMU虽然也抑制Fv/Fm 的恢复 ,但可逆转

武汉东湖颗粒悬浮物的结构与元素组成

本研究于１９８９－１９９０对武汉东湖营养水平不同的二个湖区的颗粒悬浮物的干物质结构和元素组成进行了分析．综合平均值表明，浮游动物的现存量约为浮游植物的１／４，浮游动物群落以小型的原生动物和轮虫占优势．从年平均值来看，浮游生物的干重占颗粒悬浮物干物质的２．５—７．６％，浮游生物碳量占颗粒悬浮物碳量的４．０—９．８％；颗粒悬浮物的碳／氮比与一般浮游植物的比值相似，但明显大于多数浮游动物；颗粒悬浮物的碳与干物重之比约为一般浮游生物的３／４；颗粒悬浮物的灰分含量约为４５％，显著高于除硅藻以外的其它浮游生物。从数量

鳗鲡爱德华氏病的研究

本文记述了在我国新发现的鳗鲡爱德华氏病的症状和病原菌的特征。病鱼的症状表现为两大类型,以肾脏病变为主的肾脏型和以肝脏病变为主的肝脏型。从病鱼的内脏分离到7株菌,用其中的E86～205进行人工感染,100％的鳗鲡死亡,与自然发病的症状相似,从感染的鳗鲡上又重新分离到菌株E86-203。E86-203与E86-205以及其他菌株的特征也都一致。均为革兰氏阴性杆菌。菌体直,两端圆形,单个,大小为0.6—0.8×0.8—2.4微米。周鞭毛,运动,兼性厌氧,发酵葡萄糖产酸产气。氧化酶阴性,过氧化氢酶阳性,产生硫化氢

Detection and quantitative analysis of polychlorinated biphenyls in tilapia from Hawaiian waters

The purpose of this study was to investigate polychlorinated biphenyls (PCBs) contamination in tilapia (Oreochromis mossambicus) collected from the Manna stream and Ala Wai Canal of O'ahu, an island of the geographically isolated Hawaiian archipelago. Our results show that the average concentrations of PCBs varied from 51.90 to 89.42 ng g(-1) lipid weight for the sampling sites. Relative toxic potencies (RTPs) and toxic equivalencies (TEQs) were determined to be 20.38-40.60 ng TCDD g(-1) lipid weight and 2.89-4.17 ng TEQ g(-1) lipid weight by 7-ethoxy-resorufin-O-deethylase (EROD) activity analysis and calculation of PCB concentrations based on toxic equivalency factors (TEFs), respectively. Penta-chlorinated congeners were found to be predominant, which revealed that Aroclor 1254 was a possible major source of PCBs in our fish samples. PCB 118, an indicator PCBs, constituted more than 55% and 30% of the total PCBs and TEQs, respectively. In addition, PCB 118 was found to have a linear correlation to the total PCBs (R = 0.975) and TEQs (R = 0.782). Detection of concentrated PCBs in Hawaiian waters suggests a potentially adverse impact of this pollutant on human health, as well as ecological systems, and suggests the necessity of environmental monitoring and hazard assessment of PCBs within the Hawaiian Islands. (c) 2008 Published by Elsevier Ltd.

Relationship between the allelopathic activity and molecular structure of hydroxyl derivatives of benzoic acid and their effects on cyanobacterium Microcystis aeruginosa

The antialgal activities of benzoic acid, 2-hydroxybenzoic acid (salicylic acid), 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 3,5-dihydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid (gallic acid) were studied on the growth of two strains of Microcystis aeruginosa (toxic FACHB 942 and non-toxic 469). The results showed that the sequence of 50% growth inhibition concentration (ErC50) of 6- compounds for both strains of M. aeruginosa followed the same order: gallic acid > 3,5-dihydroxybenzoic acid > 4-hydroxybenzoic acid > salicylic acid > 3-hydroxybenzoic acid > benzoic acid. The position and the numbers of hydroxy groups between the hydroxy group and carboxyl influenced the antialgal effects of phenolic acids. We also investigated the joint effects of benzoic acid, 4-hydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid on the growth of M. aeruginosa ( toxic FACHB 942). The mixture of phenolic allelochemicals showed the synergistic effects.

Elevated levels of urinary 8-hydroxy-2'-deoxyguanosine in male electrical and electronic equipment dismantling workers exposed to high concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans, polybrominated diphenyl ethers, and polychlorinated biphenyls

To investigate the occupational exposure levels to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), indoor dust (n = 3) in workshops and hair samples from male workers (n = 64) were collected at two electrical and electronic equipment waste (E-waste) dismantling factories located in the LQ area in east China in July 11-13, 2006. Pre- and postworkshift urines (64 of each) were also collected from the workers to study oxidative damage to DNA using 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a biomarker. The concentrations of PCDD/Fs, PCDD/F-WHO-TEQs, PBDEs, PCBs and PCB-WHO-TEQs were (50.0 +/- 8.1) x 10(3), 724.1 +/- 249.6, (27.5 +/- 5.8) x 10(6), (1.6 +/- 0.4) x 10(9), (26.2 +/- 3.0) x 10(3) pg/g dry weight (dw) in dust, and (2.6 +/- 0.6) x 10(3), 42.4 +/- 9.3, (870.8 +/- 205.4) x 10(3), (1.6 +/- 0.2) x 10(6), 41.5 +/- 5.5 pg/g dw in hair, respectively. The homologue and congener profiles in the samples demonstrated that high concentrations of PCDD/Fs, PBDEs, and PCBs were originated from open burning of E-waste. The 8-OHdG levels were detected at 6.40 +/- 1.64 mu mol/mol creatinine in preworkshift urines. However, the levels significantly increased to 24.55 +/- 5.96 mu mol/mol creatinine in postworkshift urines (p < 0.05). Then, it is concluded that there is a high cancer risk originated from oxidative stress indicated by the elevated 8-OHdG levels in the E-waste dismantling workers exposed to high concentrations of PCDD/Fs, PBDEs, and PCBs.

Toll-like receptor 3 regulates Mx expression in rare minnow Gobiocypris rarus after viral infection

Toll-like receptor 3 (TLR3) plays a key role in activating immune responses during viral infection. To study the genes involved in the regulatory function of TLR3 in the rare minnow Gobiocypris rarus after viral infection, a full-length cDNA of TLR3 (GrTLR3) with a splice variant (GrTLR3s) was identified by homologous cloning and RACE techniques. The antiviral effector molecule Mx gene was cloned and partially sequenced. The mRNA expression levels of GrTLR3, GrTLR3s, and Mx were studied in different tissues before and after virus infection by real-time quantitative RT-PCR. The transcripts of all three genes in liver were significantly increased following GCRV infection (P<0.05). The mRNA levels in liver were upregulated at 24 h post-injection for GrTLR3 and GrTLR3s, and at 12 h for Mx. The upregulated expression levels were several folds for GrTLR3s, tens of folds for GrTLR3, and hundreds of folds for Mx. By semi-quantitative RT-PCR, GrTLR3 and Mx expressed at all the developmental stages, whereas GrTLR3s could only be detected at later developmental stages. Using RNAi and transgenic techniques, GrTLR3 mediated Mx expression but GrTLR3s did not. The time-dependent upregulation of receptor and effector, and the Mx over-expression dependent on TLR3, indicated that GrTLR3 regulated Mx expression in viral infection through a configuration change in rare minnow, and its splice variant did not contribute to the process.

Generation and characterization of monoclonal antibodies against the flounder Paralichthys olivaceus rhabdovirus

Two MAbs (3C7 and 3C9) against flounder Paralichthys olivaceus rhabdovirus (PORV) were generated with hybridoma cell fusion technology and characterized by an indirect enzyme-linked immunosorbent assay, isotype test, Western blot and immunodot analysis and immunofluorescence assay. Isotyping tests demonstrated that both of the two MAbs belonged to IgM subclass. Western blot analysis showed the MAbs reacted with 42, 30, and 22 kDa viral proteins, which were localized within the cytoplasm of PORV-infected grass carp ovary (GCO) cells analyzed by indirect immunofluorescences tests. The MAb 3C7 was also selected at random for detecting virus antigens in the inoculated grass carp tissues by immunohistochemistry assay. Flow cytometry tests showed that at the 36 h postinfection (0.25 PFU/cell), the 23% PORV-infected GCO cells could be distinguished from the uninfected cells with the MAb 3C7. Such MAbs could be useful for diagnosis and potential treatment of viral infection. (C) 2007 Elsevier B.V. All rights reserved.

Increasing the genetic uniformity of bighead carp [Aristichthys nobilis (Richardson)] by means of spontaneous diploidization of gynogenetically activated eggs

Three groups of gynogenetic diploid bighead carp were successfully obtained by means of artificial gynogenesis. The activation rates of gynogenesis varied from 75.9% to 98.8%, and the frequency of spontaneous diploidization was around 0.4%. Over 2000 normally gynogenetic diploid fry were obtained in three gynogenetic groups. The haploid karyotype consisted of nine metacentric, 12 submetacentric, three subtelocentric chromosomes and 45 arms. The chromosome number was 48 from gynogenetic diploid. The results showed that the genetic material of offspring was maternal. The aneuploid hybrid embryos of bighead carp and Xingguo red common carp with chromosome numbers ranging from 28 to 73 did not survive post hatch, likely the result of incompatibility between the nucleus and the cytoplasm of two parents. Sixty RAPD primers from three groups were used for total DNA amplification of gynogenetic offspring, maternal and 'paternal' fish. A total of 451 bands were amplified from three kinds of samples above. From maternal bighead carp, 256 bands were amplified; however, there were 251 shared bands between maternal and gynogenetic bighead carp. From artificial gynogenetic offspring, two 'paternal' DNA segments without an expression function were found. An UPGMA tree showed that gynogenetic offspring were closely clustered and the genetic identity among them was very high (0.956).

Primary cultured cells as sensitive in vitro model for assessment of toxicants-comparison to hepatocytes and gill epithelia

In an effort to develop cultured cell models for toxicity screening and environmental biomonitoring, we compared primary cultured gill epithelia and hepatocytes from freshwater tilapia (Oreochromis niloticus) to assess their sensitivity to AhR agonist toxicants. Epithelia were cultured on permeable supports (terephthalate membranes, "filters") and bathed on the apical with waterborne toxicants (pseudo in vivo asymmetrical culture conditions). Hepatocytes were cultured in multi-well plates and exposed to toxicants in culture medium. Cytochrome P4501A (measured as 7-Ethoxyresorufin-O-deethylase, EROD) was selected as a biomarker. For cultured gill epithelia, the integrity of the epithelia remained unchanged on exposure to model toxicants, such as 1,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), benzo(a)pyrene B[a]P, polychlorinated biphenyl (PCB) mixture (Aroclor 1254), and polybrominated diphenyl ether (PBDE) mixture (DE71). A good concentration-dependent response of EROD activity was clearly observed in both cultured gill epithelia and hepatocytes. The time-course response of EROD was measured as early as 3 h, and was maximal after 6 h of exposure to TCDD, B [alp and Aroclor 1254. The estimated 6 h EC50 for TCDD, B [a]P, and Aroclor 1254 was 1.2x10(-9), 5.7x10(-8) and 6.6x10(-6) M. For the cultured hepatocytes, time-course study showed that a significant induction of EROD took place at 18 h, and the maximal induction of EROD was observed at 24 h after exposure. The estimated 24 It EC50 for TCDD, B[a]P, and Aroclor 1254 was 1.4x10(-9), 8.1x10(-8) and 7.3x10(-6) M. There was no induction or inhibition of EROD in DE71 exposure to both gill epithelia and hepatocytes. The results show that cultured gill epithelia more rapidly induce EROD and are slightly more sensitive than cultured hepatocytes, and could be used as a rapid and sensitive tool for screening chemicals and monitoring environmental AhR agonist toxicants. (c) 2006 Elsevier B.V. All rights reserved.

Estimated detection distance of a baiji's (Chinese river dolphin, Lipotes vexillifer) whistles using a passive acoustic survey method

Source levels and phonation intervals of whistles produced by a free-ranging baiji (Chinese river dolphin) were measured in the seminatural reserve of Shishou in Hubei, China. A total of 43 whistles were recorded over 12 recording sessions. The mean dominant frequency (the frequency at the highest energy) was 5.7 kHz (s.d.=0.67). The calculated source level was 143.2 dB rms re 1 mu Pa (s.d.=5.8). Most phonation intervals were shorter than 460 s, and the average interval was 205 s (s.d. = 254). Theoretical detection range of baiji's whistle was 6600 m at the present study site, but it could reduce a couple of hundred meters in practical noisy situation in the Yangtze River. Sporadic phonation (205 s interval on average) with relatively faint signal of baiji was considered, to be difficult to be detected by a towing hydrophone system. Stationed monitoring or slow speed towing of hydrophones along the river current is recommended. (c) 2006 Acoustical Society of America.

Respiratory pattern of captive Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis)

Cetacean respiration usually happen in bouts. The most widely applied quantitative method used to analyze the structure of these bouts is the log(e)-survivorship analysis, based on the assumption that the respiratory intervals are distributed as negative exponentials. However, for the data collected from three captive Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis), we failed to obtain a convergent result with the application of log,survivorship analysis. However, the two-Gaussian model, which was recently proposed to analyze the feeding behavior of cows, was successfully fitted to the data. According to the fitting results, the overall respiratory pattern of the captive Yangtze finless porpoises can be described as a dive with a mean duration of around 30-40 s, followed by two or three ventilations with a mean interval of approximately 9 s. The average intra-bout intervals during both active and inactive periods are constant at 7.7-9.9 s for all individuals. However, when shifting from active to inactive states, the adult male and female decrease their mean numbers of respirations per bout and average length of inter-bout respiratory intervals, while the estimates of both parameters increase for the juvenile female. It was pointed out that the two-Gaussian model might be more adequate for cetacean respiratory-bout structure analyses than the log(e)-survivorship technique.