oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Spatial Patterns of Genetic Differentiation in Brachionus calyciflorus Species Complex
萼花臂尾轮虫种复合体遗传分化的空间格局

XIANG Xian-Ling,XI Yi-Long,WEN Xin-Li,ZHANG Jin-Yan,MA Qin,
项贤领
,席贻龙,温新利,张晋艳,马芹

动物学研究 , 2010,
Abstract: 对采自中国东部八个地理区域中的萼花臂尾轮虫种复合体(Brachionus calyciflorus species complex)内124个轮虫克隆的核DNA ITS区进行了测序和分析,重建了萼花臂尾轮虫种复合体的系统发生树。研究发现73个单倍型聚合为三个支系,支系间序列差异百分比为4.2%-25.3%,表明萼花臂尾轮虫实际上是由三个隐种组成的种复合体,在广州、儋州和芜湖采样点均具有隐种共存现象。萼花臂尾轮虫种复合体的核苷酸多样性和单倍型多样性均较高,隐种III内各种群间遗传分化指数也较高,这可能是由于栖息地的片段化、有限的基因流以及在冰期瓶颈后拓殖种群的快速增长阻碍了有效基因流,加速了地理种群间的遗传分化。巢式支系分析显示部分巢支具有一定的系统地理格局,而Mantel检验表明种群间平均净遗传距离及遗传分化指数和地理距离间均没有显著的相关性。末次盛冰期之后的新仙女木事件(YD Event)可能对我国萼花臂尾轮虫隐种的分布和地理格局造成较大影响。在YD时期,三个萼花臂尾轮虫隐种可能退缩并共存于南岭以南地区的多个残遗种避难所,而此后的休眠卵长距离拓殖并伴随后期的栖息地片段化可能是形成当前地理格局的主要原因。萼花臂尾轮虫种复合体在全球范围内的地理分布可能与大陆板块构造运动有关。
A comparative study on effects of three freshwater algae species on rotifer Brachionus calyciflorus cultivation
三种淡水藻类对萼花臂尾轮虫培养效果的比较

LI Xiang,ZHANG Qing-Jing,LI Kai,
李香
,张清靖,李凯

生态学报 , 2006,
Abstract: 在28℃下,采用群体累积培养法,探讨了不同浓度的蛋白核小球藻(Chlorella pyrenodeosa)、水华鱼腥藻(Anabaena flas-aquae)和沙角衣藻(Chlamyclomoras sajao),以及在等生物量条件下,以上3种藻类两两配比饵料(3:1、1:1和1:3)对萼花臂尾轮虫(Brachionus calyciflorus)的培养效果。结果表明,不同浓度的蛋白核小球藻、水华鱼腥藻和沙角衣藻对萼花臂尾轮虫增殖效果的影响分别表现为差异极显著(P〈0.01)、显著(P〈0.05)和不显著(P〉0.05);蛋白核小球藻与水华鱼腥藻组成的混合饵料对萼花臂尾轮虫的增殖效果均优于其中的单一种类(P〈0.05);沙角衣藻无论是单独投喂,还是与其它藻类混合投喂,轮虫的培养效果均不理想。因此,该种类不宜用作轮虫饵料开发。该研究还表明,蛋白核小球藻是培养萼花臂尾轮虫的最适单一种类,它与水华鱼腥藻组成的混合饵料培养萼花臂尾轮虫效果更好。
萼花臂尾轮虫(Brachionus calyciflorus)COI基因序列变异及种群遗传结构分析  [PDF]
董云伟,牛翠娟
海洋与湖沼 , 2004,
Abstract: 利用线粒体细胞色素氧化酶亚基I(cytochrome oxidase I,COI)基因序列对北京地区和江汉湖群部分湖泊萼花臂尾轮虫(Brachionus calyciflorus)种群遗传结构进行了初步分析。以特异引物进行PCR扩增,获得了661bp的基因片断序列,所得序列与Genbank中B.calyciflorus COI序列的同源性为82%—93%。在6个种群中,共获得了15种单元型。序列分析结果表明,不同季节单元型之间的遗传距离较大(0.248—0.263),而在同一季节单元型之间遗传距离较小(0.002—0.031)。种群遗传结构分析表明,各种群之间无共享的单元型,同一季节不同湖泊种群之间存在着一定程度的遗传分化,但未按照地理位置形成明显的地理格局。按采样时间分组进行AMOVA分析,组间差异高达94.09% ;DH-I与其他种群之间存在着明显的遗传分化。同一湖泊不同季节样品之间,遗传变异较大,这表明在同一湖泊存在着不同基因型的轮虫休眠卵,当环境条件发生了变化后,不同基因型之间会发生更迭。
Effects of Initial Population, Food Quantities and Temperature on Population Growth of Brachionus calyciflorus  [PDF]
TIAN Bao-jun,DING Qian,LI Ying-wen
Journal of Chongqing Normal University , 2009,
Abstract: Brachionus calyciflorus is the great starting food to freshwater larval. There are many environment factors effecting their growth and increase. The different initial population densities, food quantities and temperature of Brachionus calyciflorus cultured under different conditions are studied in this paper. Initial population densities are chosen from 4 grads: 5, 15, 20 and 35 individuals per mL; food quantities are chosen from 3 grads: 1 g of yeast for a hundred million individuals of rotifer per day, 5 g of yeast for a hundred million individuals of rotifer per day, 10 g of yeast for a hundred million individuals of rotifer per day; temperatures are chosen from 4 grads: 20,25,30 and 35℃. The results show as follow: 1) about 20 individuals per mL of initial population densities is the optimum density for rotifer with yeast in this experiment. The population can not adapt the new environment in lower initial population densities. The average increasing rate is lower in higher initial population densities. 2) 5 g of yeast for a hundred million individuals of rotifer per day is more suitable than other food quantities for the population. The rotifers grow slowly and the body size is small in lower food quantities. The water is polluted seriously in higher food quantities. 3) The growth of Brachionus calyciflorus is better at 30℃; the rotifers breed slowly when temperature is lower than 30℃; and they can not live when the temperature higher than 30℃.
Effect of different densities of live and dead Chlorella vulgaris on the population growth of rotifers Brachionus calyciflorus and Brachionus patulus (Rotifera)
Lucía-Pavón,E.; Sarma,S.S.S.; Nandini,S.;
Revista de Biología Tropical , 2001,
Abstract: in order to maintain rotifer populations during periods of low algal production, it is necessary to offer alternate diets, some of which include forms of preserved algae. the present work is based on the effect of live and dead chlorella vulgaris on the population growth of brachionus calyciflorus and brachionus patulus. the experimental design consisted of 3 algal levels (0.5x106, 1.5x106 and 4.5x106 cells ml-1) offered in 3 forms (living, frozen and heat-killed). the maximal population density values for b. calyciflorus ranged from 55±1 ind. ml-1 (at 0.5x106 cells ml-1) to 471±72 ind. ml-1 (at 4.5x106 cells ml-1) with live chlorella, but was much lower (6±1 to 26±6 ind. ml-1) with frozen or heat-killed alga under comparable food levels. however, the maximum population density of b. patulus under live or or heat-killed chlorella was similar at comparable algal levels but when offered frozen algae it was four times less. the highest mean peak population density was 1227±83 ind. ml-1 under 4.5x106 cells ml-1. the rate of population increase for b. calyciflorus varied from 0.50 to 0.79 using live chlorella, but under comparable conditions, this range was lower (0.21 to 0.31) for b. patulus. results have been discussed in light of possible application for aquaculture
Effect of different densities of live and dead Chlorella vulgaris on the population growth of rotifers Brachionus calyciflorus and Brachionus patulus (Rotifera)  [cached]
E. Lucía-Pavón,S.S.S. Sarma,S. Nandini
Revista de Biología Tropical , 2001,
Abstract: In order to maintain rotifer populations during periods of low algal production, it is necessary to offer alternate diets, some of which include forms of preserved algae. The present work is based on the effect of live and dead Chlorella vulgaris on the population growth of Brachionus calyciflorus and Brachionus patulus. The experimental design consisted of 3 algal levels (0.5x10(6), 1.5x10(6) and 4.5x10(6) cells ml-1) offered in 3 forms (living, frozen and heat-killed). The maximal population density values for B. calyciflorus ranged from 55±1 ind. ml-1 (at 0.5x10(6) cells ml-1) to 471±72 ind. ml-1 (at 4.5x10(6) cells ml-1) with live Chlorella, but was much lower (6±1 to 26±6 ind. ml-1) with frozen or heat-killed alga under comparable food levels. However, the maximum population density of B. patulus under live or or heat-killed Chlorella was similar at comparable algal levels but when offered frozen algae it was four times less. The highest mean peak population density was 1227±83 ind. ml-1 under 4.5x10(6) cells ml-1. The rate of population increase for B. calyciflorus varied from 0.50 to 0.79 using live Chlorella, but under comparable conditions, this range was lower (0.21 to 0.31) for B. patulus. Results have been discussed in light of possible application for aquaculture Para mantener poblaciones de rotíferos durante periodos con escasez de microalgas, es necesario ofrecer dietas alternativas, incluyendo algunas formas de microalgas preservadas. El presente trabajo analiza el efecto de Chlorella vulgaris viva y muerta sobre el crecimiento poblacional de Brachionus calyciflorus y Brachonus patulus. El dise o experimental consistió en tres niveles de algas (0.5x10(6), 1.5x10(6) y 4.5x10(6) células ml-1) ofrecidas en tres formas (viva, congelada y muerta con agua caliente). Las abundancias máximas de población de B. calyciflorus variaron desde 55±1 ind. ml-1 (en 0.5x10(6) células ml-1) a 471±72 ind. ml-1 (en 4.5x10(6) células ml-1) con Chlorella viva, mientras que, cuando se utilizó alga congelada o muerta con agua caliente, la abundancia fue mucho menor (6±1 a 26±6 ind. ml-1). Sin embargo, la máxima densidad de población de B. patulus con Chlorella viva o muerta con calor fue similar bajo niveles de algas comparables, mientras que cuando se ofreció alga congelada, la abundancia fue cuatro veces menor. La abundancia máxima de B. patulus fue 1 227±83 ind. ml-1 bajo 4.5x10(6) células ml-1. La tasa de crecimiento poblacional de B. calyciflorus varió desde 0.50 hasta 0.79 usando Chlorella viva, pero bajo las mismas condiciones, el rango es menor (0.21 a 0
Differentiation between activity of digestive enzymes of Brachionus calyciflorus and extracellular enzymes of its epizooic bacteria  [cached]
Martina ?TROJSOVá,Wilko H. AHLRICHS
Journal of Limnology , 2009, DOI: 10.4081/jlimnol.2009.409
Abstract: The rotifer Brachionus calyciflorus was examined by scanning electron microscopy (SEM) for surface-attached, i.e. epizootic, bacteria to ascertain their specific localization and thus find out if we could discern between rotifer and bacterial enzyme activity. The lorica of B. calyciflorus was colonized by one distinct type of bacteria, which originated from the algal culture used for rotifer feeding. The corona, posterior epidermis and foot of all inspected individuals were always without attached bacteria. The density of the attached bacteria was higher with the increasing age of B. calyciflorus: while young individuals were colonized by ~ tens of bacterial cells, older ones had on average hundreds to thousands of attached bacteria. We hypothesize that epizooic bacteria may produce the ectoenzymes phosphatases and β-N-acetylhexosaminidases on the lorica, but not on the corona of B. calyciflorus. Since enzyme activities of epizooic bacteria may influence the values and interpretation of bulk rotifer enzyme activities, we should take the bacterial contribution into account.
The Effect of Caloric Restriction on the Life Span and Reproduction of Fresh Water Rotifer (Brachionus calyciflorus)
Nilgun Ozdemir
Journal of Animal and Veterinary Advances , 2012,
Abstract: The effect of Caloric Restriction (CR) on life span of fresh water rotifer (Brachionus calyciflorus) was investigated in this study. Groups were fed at 12, 24, 36, 48, 60 and 72 h intervals with 0.5 mL (1.5x106 cell mL-1) Chlorella sp. to apply CR. Significant changes were observed in maximum and average life spans in groups subjected to CR (p<0.05). Maximum life span in 36 h group was determined as 15 days, while it was 10 days in control group. Reproduction life span was observed to be increasing in spite of decreasing number of eggs. The results show that CR affected life span and reproduction in rotifer B. calyciflorus.
Optimization of Indoor Production of Fresh Water Rotifer, Brachionus calyciflorus, b: Feeding Studies  [PDF]
Muhammad Ashraf,Sana Ullah,Tariq Rashid,Mohammad Ayub
Pakistan Journal of Nutrition , 2010,
Abstract: Brachionus calyciflorus is commonly found in fresh water ponds. Its production depends on unrelenting supply of Chlorella in sufficient quantity. In the current studies a water sample was collected from fish culture ponds by Wisconsin plankton net (64 μm mesh). The freshly collected stock was concentrated and fractionated by passing through 600, 200, 125, 75 and 38 μm sieves arranged vertically with gradual decrease in pore size. The pure Brachionus calyciflorus were fed on Chlorella available in the laboratory. Algae was gradually replaced by yeast to reduce dependency on labour intensive live food. Maximum number of rotifers 413 ml-1, was observed when they were fed on 160:32 yeast:algae ratio by weight combination. Ciliates and cyclops posed a major threat during culture and frequent crashes were observed due to this menace. Cyclops were selectively eradicated from the rotifer culture at 0.09 DDVP after 20 h of exposure but not ciliates. There was no selective mortality in ciliates at any stage. Nevertheless both ciliates and rotifers were dead at 0.2 ppm. Simple method of cyst preservation is mentioned.
Population dynamics of Brachionus calyciflorus (Rotifera: Brachionidae) in waste water from food-processing industry in Mexico  [cached]
Raymundo Alfredo Arévalo Stevenson,S.S.S. Sarma,S. Nandini
Revista de Biología Tropical , 1998,
Abstract: Waste water from Mexico's largest food processing industrial sector (based on maize, nejayote water) was used for growing Brachionus calyciflorus isolated from Lake Chapultepec in the Federal District of Mexico (D.F.). Nejayote water was collected from Colonia Providencia, D.F. Experiments were conducted at 25°C in 25 ml capacity vials with 20 ml of medium into which we introduced B. calyciflorus at an initial density of 1 ind ml-1. The experimental design consisted a total of 33 test vessels (2 food combinations X 5 densities X 3 replicates = 30 plus 3 replicates as controls that contained only algae). Experiments were terminated after day 16. Waste water in original concentration did nt rotifes. However, when diluted to 5 oncentrations (ranging from 2% to 32% and pH adjusted to 7.0), rotifer density increased with increasing concentration of waste water. Green algae (at constant density of 2 X 10 6 cells-1 of Chlorella) in combination with waste water resulted in a higher abundance of rotifers only at higher concentration (above 8 %) of waste water. The maximum peak density of rotifers (238-50 ind ml -1) was obtained at 16% dilution of waste water nd with addition of Chlorella. The rate of population increase per day (mean-SD) varied from 0.355-0.059 to 0.457-0.048 depending on food combination and concetration. Se usó aguas de desecho de la industria de la masa y la tortilla (aguas de nixtamal o nejayote) para crecer rotíferos de agua dulce, Brachionus calyciflorus. El nejayote sin dilución no permitió el desarrollo del rotífero. Sin embargo, cuando se diluyó, B. calyciflorus aprovechó la materia orgánica. El agua de desecho por sí misma (sin alimento algal adicional) fue comparable al agua con densidades del alga Chlorella de 2 X 10(6) células ml-1. Concentraciones de nejayote por encima del 8% no permitieron el crecimiento poblacional. Sin embargo, la presencia de alga permitió el desarrollo del rotífero a concentraciones de 8% y 16%. Nuestros hallazgos indican que el nejayote puedo ser utilizado de manera efectiva para la producción de rotíferos a gran escala para la acuacultura.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.