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41.
Pierre Feutry Philippe Keith Christophe Pécheyran Fanny Claverie Tony Robinet 《Ecology of Freshwater Fish》2011,20(4):636-645
Abstract – Strontium/Calcium (Sr/Ca) and Barium/Calcium (Ba/Ca) ratios were measured in 60 otoliths of the French Polynesian flagtail Kuhlia malo. Both elemental ratios were needed to correctly distinguish residence in marine, brackish and fresh water. High Sr/Ca and low Ba/Ca around the nucleus of all otoliths provided evidence of marine residency during the early life of all individuals. At about 0.5 mm from the core, Ba/Ca increased rapidly and remained high in all otoliths. High and unstable Sr/Ca ratios were attributed to estuarine residency, whereas low and stable Sr/Ca ratios were attributed to freshwater residency. These chemical signatures inferred that following recruitment to rivers, some fish remained in the estuary, while others moved upstream. Some individuals shared their time between fresh and brackish waters later in life. The findings of this study have important implications for the protection of nearshore, brackish and freshwater environments for the conservation of this French Polynesian diadromous species. 相似文献
42.
Two 60‐day experiments were conducted sequentially to determine (i) lysine requirement of juvenile bluegill, Lepomis macrochirus based on the dose–response method, (ii) requirements for other essential amino acids (EAAs) using whole‐body amino acid profile and (iii) whether differences in growth rates of group‐housed versus individually‐housed bluegills lead to different lysine requirement levels because of the presence and absence, respectively, of social hierarchies. Seven, semi‐purified, experimental diets (isonitrogenous, isocaloric) were prepared to contain graded levels of digestible lysine (10–31 g kg−1). Experiment‐1 involved group‐housed bluegills (approximately 27 g, n = 10 fish/chamber, 4 chambers/diet) whereas experiment‐2 involved individually‐housed bluegills (approximately 30 g, n = 1 fish/chamber, 14 chambers/diet). Fish were fed twice daily to apparent satiation. Bluegill growth responses in both experiments generally improved (P < 0.05, anova ) with increasing dietary lysine levels from 10 to 16 g kg−1, and then levelled off with further increase in lysine level (P > 0.05). Optimal dietary lysine level (digestible basis) was estimated to be 15 g kg−1 based on broken‐line regression analyses of relative growth rate and feed conversion ratio with no differences being observed between the two rearing methods. Determined dietary requirement levels for other EAAs ranged from 2.4 g kg−1 (tryptophan) to 15.3 g kg−1 (leucine). 相似文献
43.
G. Tuitert Y. Hofmeester 《European journal of plant pathology / European Foundation for Plant Pathology》1994,100(1):19-53
A field experiment was set up in 1988 to study the development of rhizomania disease of sugar beet at different inoculum levels of beet necrotic yellow vein virus (BNYVV) in soil. Five, tenfold different, inoculum levels were created by addition of the approximate amounts of 0, 0.5, 5, 50 and 500 kg infested soil per ha (the latter corresponding to 0.01% v/v calculated to the tillage layer). A drip irrigation treatment was applied to study the influence of soil moisture on disease. Susceptible sugar beet, cv. Regina, was grown for three consecutive years.In the first year, root symptoms were not observed, but BNYVV-infected plants were detected by ELISA in low numbers at all inoculum levels at harvest. After late drilling in 1989, high numbers of infected plants, up to 90–100% in plots with the highest inoculum level, were detected already in June. Root symptoms were also observed from June onwards. In both these years disease incidence increased in time and was significantly influenced by the initial inoculum level. In the third year, the whole field was heavily diseased, and only for the non-irrigated plots incidence differed for different initial inoculum levels. The expression of symptoms by BNYVV-infected plants was influenced by initial inoculum level, thus by the amount and timing of primary infection.Root weight at harvest was not affected, but sugar content decreased with increasing inoculum level already in 1988, leading to a reduction in sugar yield of 10% at the highest inoculum level. In 1989, both root weight and sugar content decreased progressively with increasing inoculum level, resulting in sugar yield reductions of 11–66% (down to approximately 3000 kg ha–1) for low to high inoculum levels compared to the control. As the control plots became contaminated, all yields were low in 1990, still showing a decrease with increasing inoculum level in the non-irrigated plots, but an overall mean sugar yield of 3323 kg ha–1 for the irrigated ones.Sodium and -amino nitrogen content of the root, additional quality parameters determining extractability of sucrose, showed an increase and decrease, respectively, with increasing initial inoculum level already in the first year. The relative differences in contents compared to those from the control were largest for Na content. A significant negative correlation was found between Na (mmol kg–1 root) and sugar content (% of fresh weight); linear for 1988, exponential for 1989 and 1990.In spring 1989, the infestation of individual plots was assessed using a quantitative bioassay estimating most probable numbers (MPNs) of infective units of BNYVV per 100 g dry soil. The relationship between the MPns determined and root weight, sugar content and sugar yield at harvest could be described by Gompertz curves. The increase in disease incidence with increasing MPN in 1989 was adequately fitted with a logistic equation. 相似文献
44.
45.
应用于家蚕F2代分离群体的两种连锁作图方法的作图效果比较 总被引:1,自引:0,他引:1
构建精细的家蚕分子连锁图谱需要合适的作图方法。应用Mapmaker/EXP3.0和F2lnkgsilk两种作图方法,对家蚕F2代91个个体为分离群体的300个AFLP标记和69个个体为分离群体的470个RAPD标记数据进行了比较分析。用F2lnkgsilk作图方法分析得到的分群数与Mapmaker/EXP3.0作图方法相比有所增加,而总的图距却显著增加,平均图距也有较大的增加,但产生的二联体数基本相同。就单个连锁群而言,两种作图分析方法的连锁标记及其数目80%以上相同,但是标记间的排列顺序70%以上有差异;用F2lnkgsilk作图方法分析得到的单个连锁群的总图距和平均图距也相应增大。 相似文献
46.
Doobyeong Chae Zahid Manzoor Sung Chun Kim Sohyun Kim Tae-Heon Oh Eun-Sook Yoo Hee-Kyoung Kang Jin-Won Hyun Nam Ho Lee Mi-Hee Ko Young-Sang Koh 《Marine drugs》2013,11(9):3272-3287
Sargassum muticum (S. muticum) is a brown edible alga and widely distributed in Korea. This report was designed to evaluate the anti-inflammatory properties of apo-9′-fucoxanthinone (APO-9′) isolated from S. muticum on pro-inflammatory cytokine production.
S. muticum extract (SME) exhibited significant inhibitory effects on pro-inflammatory cytokine production in bone marrow-derived macrophages (BMDMs) and dendritic cells (BMDCs). APO-9′ pre-treatment in the CpG DNA-stimulated BMDMs and BMDCs showed a strong dose-dependent inhibitory effect on interleukin (IL)-12 p40, IL-6 and tumor necrosis factor (TNF)-α production with IC50 values ranging from 5.31 to 13.79. It exhibited a strong inhibitory effect on the phosphorylation of ERK1/2 and on activator protein (AP)-1 reporter activity. APO-9′ pre-treatment exhibited significant inhibition of CpG DNA-induced production of inducible nitric oxide synthase. Taken together, these data suggest that SME and APO-9′ have a significant anti-inflammatory property and warrant further studies concerning the potentials of SME and APO-9′ for medicinal use. 相似文献
47.
48.
CAD/CAM应用越来越广泛,但对于CAD/CAM应用软件的选型是一些设计人员及企业面临的问题,文章介绍了CAD/CAM软件系统的组成,CAD/CVM应用软件的选型要素,企业选型时应注意的事项. 相似文献
49.
杉木人工林凋落物分解对氮沉降增加的响应 总被引:5,自引:2,他引:5
通过野外模拟试验,研究了杉木人工林凋落叶分解对氮沉降增加的响应。试验设计为4种处理:N0(0 kg/(hm2·a),对照)、N1(60 kg/(hm2·a))、N2(120 kg/(hm2·a))、N3(240 kg/(hm2·a)),每种处理重复3次。经660 d分解后,N0、N1、N2、N3处理凋落物残留率分别为24.58%、21.99%、15.46%和25.17%,分解系数分别为0.776 4、0.807 6、1.018 8和0.760 8,95%的凋落物分解所需时间分别为3.99、3.95、3.06和4.11年,表明N1、N2 促进了凋落物的分解,而N3则表现出一定的抑制作用。模拟氮沉降在一定程度增加了凋落叶中的氮含量,从而降低了碳氮比。除N3处理外,凋落物分解系数与凋落物中的氮含量呈显著的正线性关系,而与碳氮比呈负相关。 相似文献
50.