Establishment of trophic continuum in the food web of the Yellow Sea and East China Sea ecosystem: Insight from carbon and nitrogen stable isotopes

The determination of trophic level for the biology in a marine ecosystem is very important as alteration of its structure and function may be reflected in the tro-phic level of component species. A change in trophic level indicates variation in an organism’s feeding bi-ology or in the pathway of energy flow from primary producers to the consumer. The gut content analysis is a traditional method for studying trophodynamics of food web in marine ecosystems. Species composition and amounts in al…     

夏季若尔盖高寒湿地水生生物群落食物网结构特征

为了解若尔盖高寒湿地夏季水生生物群落食物网结构及营养关系特征,应用稳定同位素技术分析了若尔盖湿地 3个不同区域(ZS1、ZS2和ZS3)水生生物群落碳、氮稳定同位素比值,并计算了13C-15N同位素生态位中的6个营养结构量化指标。结果显示:外源性营养源陆生植物13C、15N值分别为-28.23- -26.07,-1.20-5.98; 内源性营养源颗粒有机物 (POM:主要成分为藻类)和水生植物13C、15N值分别为-26.39- -21.17、-25.37- -24.15,3.68-6.61、3.50-4.01; 其中POM样品13C、15N组成存在明显的区域性差异(P0.05,P0.001)。食物网营养结构分析显示若尔盖湿地外源性碳源输入(优势陆生植物)对于维持该水域生态系统结构稳定有着十分重要的作用。若尔盖湿地水域食物网营养级介于2-3,暗示了其生态系统结构的相对脆弱性。同位素量化指标标记发现若尔盖湿地水生动物群落生态结构存在明显的空间异质性,可能与若尔盖湿地发达的畜牧产业相关。     

Comparison of the data, analysis, and results of X-ray absorption studies of cytochrome c oxidase

Differences in the methods of analysis of X-ray absorption data used by Powers et al. [Powers, L., Blumberg, W. E., Chance, B., Barlow, C., Leigh, J., Jr., Smith, J., Yonetani, T., Vik, S., & Peisach, J. (1979) Biochim. Biophys. Acta 547, 520-538; Powers, L., Chance, B., Ching, Y., & Angiolillo, P. (1981) Biophys. J. 34, 465-498] and Scott et al. [Scott, R., Schwartz, J., & Cramer S. (1986) Biochemistry 25, 5546-5555] are clarified. In addition, we compare the X-ray absorption data and results for resting cytochrome c oxidase reported by both groups using the same analysis method and conclude apart from any assumptions that the data are not identical.     

Leptomonas samueli glycoconjugates. Comparison with Herpetomonas samuelpessoai

Xylose and mannose are the main manosaccharide components of Herpetomonas samuelpessoai and Leptomonas samueli promastigotes. Variations in the xylose/mannose ratios are related to the age of cultures. Phenol-aqueous extraction disclosed in both species the presence of carbohydrate-containing fractions which were both soluble and insoluble in chloroform/methanol/water (10:10.3). The xylose enriched, uronic acid-containing glycoconjugates of L. samueli were mainly composed of (1----4)-linked xylose units (Methylation-mass spectrometry and 13C NMR), similar to the glucuronoxylan of H. samuelpessoai (Mendon?a-Previato et al., 1979 Biochem 18 149-154). SDS-PAGE and sugar composition analysis disclosed similarities between glycoconjugates of H. samuelpessoai and L. samueli, two species dwelling in the same host, therefore an example of convergent adaptation.     

Establishment of trophic continuum in the food web of the Yellow Sea and East China Sea ecosystem: Insight from carbon and nitrogen stable isotopes

Stable carbon and nitrogen isotope ratios (δ¹³C and δ¹⁵N) are used to study the trophic structure of food web in the Yellow Sea and East China Sea ecosystem. The trophic continuum of pelagic food web from phytoplankton to top preyer was elementarily established, and a trophic structure diagram in the Yellow Sea and East China Sea was outlined in combination with carbon isotopic data of benthic organisms, which is basically consistent with and makes some improvements on the simplified Yellow Sea food web and the trophic structure diagram drawn based on the biomass of main resource population during 1985–1986. This result indicates that the stable isotope method is a potential useful means for further studying the complete marine food web trophic continuum from viruses to top predators and food web stability.     

Stable carbon isotope ratios in Fundulus heteroclitus (L.) muscle tissue and gut contents from a North Carolina spartina marsh

Recent food habit and productivity research on the killifish, Fundulus heteroclitus (L.), suggests that this species is important in the movement of organic material within and out of the salt marsh ecosystem. The stable carbon isotope ratios of Fundulus muscle tissue and gut contents were measured seasonally to determine the carbon source of the killifish. For muscle δ¹³C values ranged from -13.9% to -15.8% and -15.8% to -18.4% for gut contents, suggesting differential assimilation of ingested material. Muscle tissue indicate that assimilated carbon probably originated from a mixture of benthic algae and Spartina ingested by major prey species: the filddle: crab, Uca pugnax (Smith): the polychaete, Nereis (Neanthes) succinea Frey and Leuckart; the tanaid, Leptochelia rapax Harger; and other small crustaceans. Small fish (age0–1 yr) showed slightly lower δ¹³C values than larger fish (age 1–3 yr), consistent with differences in their feeding habits. The only seasonal pattern was an enrichment in tissue ¹³C that occurred for both small and large fish in the spring, corresponding to the peak spawning period. The δ¹³C determination is a useful tool in identifying and tracing carbon sources through the salt marsh food web, detecting differences in feeding habits between age classes of organisms, and assessing the relative nutritive value of ingested dietary items if differential assimilation is suspected.     

Standardisation of restriction fragment length polymorphism analysis for Mycobacterium avium subspecies paratuberculosis.

DNA from 1008 strains of Mycobacterium avium subspecies paratuberculosis, digested by restriction endonucleases PstI and BstEII, was hybridised with a standard IS900 probe prepared by PCR and labelled non-radioactively by ECL. DNA fingerprints were scanned by CCD camera and analysed using the software Gel Compar (Applied Maths, Kortrijk, Belgium). Thirteen restriction fragment length polymorphism (RFLP) (PstI) types were detected, which where designated as A, B, C, D, E, F, G, H, I, J, K, L and M in accordance with the study of Pavlik et al. (1995) [Pavlik, I., Bejckova, L., Pavlas, M., Rozsypalova, V., Koskova, S., 1995. Characterization by restriction endonuclease analysis and DNA hybridization using IS900 of bovine, ovine, caprine and human dependent strains of Mycobacterium paratuberculosis isolated in various localities. Vet. Microbiol. 45, 311-318]. Twenty RFLP (BstEII) types were detected and designated as C1-3, C5, C7-20, S1 and I1 in accordance with the study by Collins et al. 1990 [Collins, D.M., Gabric, D.M., de Lisle, G.W., 1990. Identification of two groups of Mycobacterium paratuberculosis strains by restriction endonuclease analysis and DNA hybridization. J. Clin. Microbiol. 28, 1591-1596]. A combination of both RFLP (PstI) and RFLP (BstEII) results revealed a total of 28 different RFLP types. All the RFLP types and detailed protocols are available at Intemet web site WWW...: http:/ /www.vri.cz/wwwrflptext.htm.     

太湖贡湖湾食物网特征研究

应用稳定性同位素技术(13C和15N)研究了太湖贡湖湾食物网特征, 结果显示由于食物来源变化多样性影响, 导致贡湖的食物网结构和营养级关系变化较为复杂, 贡湖主要生物类群13C、15N值表现出较大的种间差异。消费者13C值从摇蚊幼虫的-32.3到锯齿米虾的-22.1, 其值大小与营养级的关系没有规律性。消费者平均15N值从褶纹冠蚌的10.3到位于顶端间下鳙的19.0, 随营养级位置而升高。群落中所有种类的15N、13C值之间没有相关性(r=0.1835, P0.05), 表明该食物网是非线性食物网。研究结果验证了杂食性生物有机体普遍存在于富营养化的贡湖水域生态系统中, 且13C结果表明, 浮游植物、固着藻类以及沉水植物为贡湖食物网中大多数生物有机体的主要碳源。贡湖食物链长度为4.44营养级。     

The Stanford Microarray Database

The Stanford Microarray Database (SMD) stores raw and normalized data from microarray experiments, and provides web interfaces for researchers to retrieve, analyze and visualize their data. The two immediate goals for SMD are to serve as a storage site for microarray data from ongoing research at Stanford University, and to facilitate the public dissemination of that data once published, or released by the researcher. Of paramount importance is the connection of microarray data with the biological data that pertains to the DNA deposited on the microarray (genes, clones etc.). SMD makes use of many public resources to connect expression information to the relevant biology, including SGD [Ball,C.A., Dolinski,K., Dwight,S.S., Harris,M.A., Issel-Tarver,L., Kasarskis,A., Scafe,C.R., Sherlock,G., Binkley,G., Jin,H. et al. (2000) Nucleic Acids Res., 28, 77-80], YPD and WormPD [Costanzo,M.C., Hogan,J.D., Cusick,M.E., Davis,B.P., Fancher,A.M., Hodges,P.E., Kondu,P., Lengieza,C., Lew-Smith,J.E., Lingner,C. et al. (2000) Nucleic Acids Res., 28, 73-76], Unigene [Wheeler,D.L., Chappey,C., Lash,A.E., Leipe,D.D., Madden,T.L., Schuler,G.D., Tatusova,T.A. and Rapp,B.A. (2000) Nucleic Acids Res., 28, 10-14], dbEST [Boguski,M.S., Lowe,T.M. and Tolstoshev,C.M. (1993) Nature Genet., 4, 332-333] and SWISS-PROT [Bairoch,A. and Apweiler,R. (2000) Nucleic Acids Res., 28, 45-48] and can be accessed at http://genome-www.stanford.edu/microarray.