甘草粗提物对鲫的免疫调节作用

本研究对中药甘草(Glycyrrhiza uralensis Fiseh)进行了粗提,将粗提物按0.5%和2%的质量分数制成药饵投喂鲫鱼(Carassius auratus)后,于第14天、28天、35天、42天5、6天采样检测其免疫指标。结果显示,低剂量组试验鱼血清溶菌酶活性逐渐升高,高剂量组在35d达到最大值(205.5±28.8)U/mL,之后略有下降。低剂量组和高剂量组试验鱼血清杀菌活性均有所波动,波动范围分别为62.0%—73.1%和75.0%—83.3%,就各期而言,对照组、低剂量组和高剂量组

香溪河库湾春季水华期间硝酸盐、磷酸盐的时空分布

在三峡水库香溪河库湾春季水华连续暴发期间(2005年2月26日—4月28日)对香溪河与长江汇合处(河口)至香溪河库湾上游库尾处总计14个采样点进行连续监测,结果表明硝酸盐和磷酸盐在库湾中存在明显的时空分布规律。在空间上,河口的硝酸盐浓度高,库尾浓度低,其变化趋势是随着与河口距离的增加而降低;磷酸盐的分布规律是库尾的浓度高,河口的浓度低,其变化趋势与硝酸盐恰好相反。各采样点硝酸盐和磷酸盐浓度在时间上也呈现出明显的规律。河口硝酸盐的浓度在不同时间变化幅度较小,库尾采样点的硝酸盐浓度的变化幅度较大,随着与河口距

原位杂交技术用于虹彩病毒对美国青蛙侵染的诊断

蛙虹彩病毒 (Rana grylio virus,RGV)能引起鱼类、两栖类和爬行类水生动物严重的系统性疾病 ,RGV是从我国患病蛙中分离到的一种虹彩病毒。体外扩增的 RGV经人工方法感染幼龄美国青蛙 (Rana grylio) ,运用原位杂交技术 ,分别对感染 1～ 3d后的蛙心、肺、肾、肠、脾、肝等 6种组织进行 RGV分子定位和检测。结果显示 ,在幼蛙的肺和肠中有较强的阳性信号 ,在其他组织中也检测到 RGV的存在。本试验探讨了 RGV感染早期在宿主体内的增殖及在不同组织中的分布状况 ,建立了一种蛙

镧对微囊藻的生长效应及被富集的动力学研究

研究了稀土元素La3+对微囊藻生长效应及其被微囊藻富集的动力学过程 .结果表明 :当La3+的添加浓度小于 2mg·l- 1 时 ,对微囊藻的生长有促进作用 ,当La3+的添加浓度大于 2mg·l- 1 时 ,微囊藻的生长受到抑制 .La3+在微囊藻中富集的动力学过程可用表面配位模型表征

用鳞片和耳石鉴定鲫年龄的比较研究

两观测者独立观测了分别采自洪湖的 1 75尾和洞庭湖的 1 6 8尾鲫样本的鳞片和耳石 ,结果显示鳞片适于鉴定年龄组成简单、生长较快的洞庭湖鲫种群的年龄 ,两观测者年轮读数的总吻合率可达 90 5% ,与耳石上年轮读数的吻合率也可高达 91 7% ;但用鳞片鉴定年龄结构复杂、生长缓慢的洪湖鲫种群年龄 ,两观测者总吻合率只有 50 9% ,各龄组吻合率随年龄上升而迅速下降 ,与耳石上年轮读数总吻合率也仅为 56 6 % ,存在比耳石低估高龄个体年龄的问题。用耳石鉴定鲫年龄具有易于识别、精确度高的优点 ,用之

我国内陆水体单殖吸虫的宿主特异性分析

报道我国内陆水体单殖吸虫的宿主特异性的研究。研究表明单殖吸虫有很强的宿主特异性 ,但不同种类的特异性有很大的差别。从目前已有的记录来看 ,60 %以上的单殖吸虫只有 1种宿主 ,约 75%的单殖吸虫的宿主仅为 1属 ,超过97%的单殖吸虫的宿主在 1科之内。没有 1种单殖吸虫可寄生于超过 3个科的宿主中 ,但大钩指环虫可在 2 3属 33种宿主中寄生。在科和属特异性水平上 ,以锚首虫科和指环虫科单殖吸虫的特异性较强 ,三代虫科次之 ,双身虫科最弱 ;而在种特异性水平上 ,这四科单殖吸虫的宿主特异性并无显著

综合生物塘中的藻类研究Ⅰ

本文报告了综合生物塘系统(SBP System)中有关藻类的部分研究结果。湖北省黄州市的城镇综合污水对藻类未显示毒性,且有刺激生长作用,但高浓度的污水可诱化出极少数畸形细胞,表明污水中可能存在诱变活性。进水的藻类生长潜力很高,和人工对照培养基相当。藻菌塘的光合生产与水温关系密切,低和高水温条件下的水柱生产率分别为1.8—4.1gO_2/m~2·d和7—10gO_2/m~2·d。水柱代谢的层化现象明显。藻类生物量(鲜重,mg/L)和 COD(mg/L)之比值为1:0.21±0.02。

异育银鲫对鱼粉等11种饲料中磷的利用率

于1988年,以三氧化二铬间接指示法,在水温22±2℃条件下,测定了平均体重为55±5g/尾的异育银鲫对鱼粉、肉骨粉、芝麻饼、虾粉、骨粉、菜籽饼、玉米粉、脱氟磷酸氢钙、磷酸二氢钙、磷酸氢钙、磷酸钙的表观消化吸收率。结果表明:异育银鲫对第一、第二、第三磷酸钙的消化吸收率是不同的,分别为81％,65％和32％,此顺序与其溶解性由大到小的顺序一致;在所测试的八种商品饲料中,对骨粉、虾粉和菜籽饼中磷的表观消化吸收率较高,分别为65％,68％和65％;对鱼粉、芝麻饼、肉骨粉三种原料中磷的表观消化吸收率较低,分别是1

梭鱼的临界温度和临界氧量

本文报道了梭鱼的临界温度和临界氧量。临界温度进行了低温和高温致死试验,临界氧量进行了浮头时和窒息时的溶氧量测定。

Microcystin-induced variations in transcription of GSTs in an omnivorous freshwater fish, goldfish

The glutathione S-transferases are important enzymes in the microcystin-induced detoxication processes. In this experiment, we cloned the full-length cDNA of alpha, pi and theta-class-like glutathione S-transferase genes from goldfish (Carassius auratus Q. Their derived amino acid sequences were clustered with other vertebrate alpha, pi and theta-class GSTs in a phylogenetic tree and the goldfish GST sequences have the highest similarity with those from common carp and zebrafish. Goldfish were i.p. injected with microcystins extract at two doses (50 and 200 mu g kg(-1) BW MC-LReq) and the relative changes of the mRNA abundance in liver, kidney and intestine were analyzed by real-time PCR. The transcription of GST alpha was suppressed in both liver and intestine, but induced in the kidney. Decreased transcription of GST theta was detected in liver, kidney and intestine in the low-dose group. The transcription of GST pi was suppressed in liver and intestine post-injection in both dose groups. These results suggested that the transcription of GST isoforms varied in different ways within an organ and among organs of goldfish exposed to MCs. (C) 2008 Elsevier B.V. All rights reserved.

Light histories influence the impacts of solar ultraviolet radiation on photosynthesis and growth in a marine diatom, Skeletonema costatum

Phytoplanktonic species acclimated to high light are known to show less photoinhibition. However, little has been documented on how cells grown under indoor conditions for decades without exposure to UV radiation (UVR, 280-400 nm) would respond differently to solar UVR compared to those in situ grown under natural solar radiation. Here, we have shown the comparative photosynthetic and growth responses to solar UVR in an indoor-(IS) and a naturally grown (WS) Skeletonema costatum type. In short-term experiment (<1 day), phi(PSII) and photosynthetic carbon fixation rate were more inhibited by UVR in the IS than in the WS cells. The rate of UVR-induced damages of PSII was faster and their repair was significantly slower in IS than in WS. Even under changing solar radiation simulated for vertical mixing, solar UVR-induced higher inhibition of photosynthetic rate in IS than in WS cells. During long-term (10 days) exposures to solar radiation, the specific growth rate was much lower in IS than WS at the beginning, then increased 3 days later to reach an equivalent level as that of WS. UVR-induced inhibition of photosynthetic carbon fixation in the IS was identical with that of WS at the end of the long-term exposure. The photosynthetic acclimation was not accompanied with increased contents of UV-absorbing compounds, indicating that repair processes for UVR-induced damages must have been accelerated or upgraded. (C) 2008 Elsevier B.V. All rights reserved.

Control of lunar and martian dust - Experimental insights from artificial and natural cyanobacterial and algal crusts in the desert of Inner Mongolia, China

Studies on the colonization of environmentally extreme ground surfaces were conducted in a Mars-like desert area of Inner Mongolia, People's Republic of China, with microalgae and cyanobacteria. We collected and mass-cultured cyanobacterial strains from these regions and investigated their ability to form desert crusts artificially. These crusts had the capacity to resist sand wind erosion after just 15 days of growth. Similar to the surface of some Chinese deserts, the surface of Mars is characterized by a layer of fine dust, which will challenge future human exploration activities, particularly in confined spaces that will include greenhouses and habitats. We discuss the use of such crusts for the local control of desert sands in enclosed spaces on Mars. These experiments suggest innovative new directions in the applied use of microbe-mineral interactions to advance the human exploration and settlement of space.

A TPR-family membrane protein gene is required for light-activated heterotrophic growth of the cyanobacterium Synechocystis sp PCC 6803

The unicellular cyanobacterium Synechocystis sp. PCC6803 can grow heterotrophically in complete darkness, given that a brief period of illumination is supplemented every day (light-activated heterotrophic growth, LAHG), or under very weak ( < 0.5 mumol m(-2) s(-1)) but continuous light. By random insertion of the genome with an antibiotic resistance cassette, mutants defective in LAHG were generated. In two identical mutants, sll0886, a tetratricopeptide repeat (TPR)-family membrane protein gene, was disrupted. Targeted insertion of sll0886 and three downstream genes showed that the phenotype was not due to a polar effect. The sll0886 mutant shows normal photoheterotrophic growth when the light intensity is at 2.5 mumol m(-2) s(-1) or above, but no growth at 0.5 mumol m(-2) s(-1). Homologs to sll0886 are also present in cyanobacteria that are not known of LAHG. sll0886 and homologs may be involved in controlling different physiological processes that respond to light of low fluence. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

Determination of some reactive oxygen species scavengers based on the peroxidase-oxidase oscillator

This paper reports a new method for detection of ROS scavengers including superoxide dismutase, ascorbic acid and glutathione based on a 'probe' of peroxidase-oxidase biochemical oscillator. The oscillation period and amplitude change with different concentrations of scavengers. The linear ranges of superoxide dismutase, ascorbic acid and glutathione are respectively 1.56 x 10(-4)-1.56 x 10(-3) mg mL(-1), 1.75 x 10(-7) -1.75 x 10(-5) mol L-1 and 9.38 x 10(-7) -7.5 x 10(-5) mol L-1. The selectivity, linearity and precision for superoxide dismutase, ascorbic acid, and glutathione are presented and discussed. The results compared well with other standard methods for determination of superoxide dismutase, ascorbic acid and glutathione. Some possible steps in the overall reaction mechanisms are discussed.