基于连续统去除法的冬小麦叶片氮积累量的高光谱评价

作物氮素状况是评价长势、提高产量和改善品质的重要指标,它对作物氮素诊断与管理具有重要意义。本文基于不同施氮水平下的冬小麦冠层光谱及相应的叶片氮积累量数据,将广泛应用于岩矿高光谱分析中的连续统去除法借用至作物冠层氮素营养状况评价。通过对550~760nm波段的冠层光谱进行连续统去除处理,提取了3个吸收特征。结果表明:在所有生育期中,叶片氮积累量均随着施氮量的增加而增大;在所有氮处理中,从起身期、拔节期、孕穗期到抽穗期,叶片氮积累量均呈先增加后减小的趋势,且在孕穗期达到峰值;在各生育期,吸收峰总面积、吸收峰左面积和吸收峰右面积均随着施氮量的增加而增大,面积归一化最大吸收深度均随着施氮量的增加而减小。通过相关分析发现:各吸收特征参数与叶片氮积累量之间均存在显著性相关,且面积归一化最大吸收深度参数的相关性最好;全生育期的相关性高于各单生育期;但从单生育期来看,孕穗期是监测叶片氮积累量最佳时期。回归分析结果发现,基于全生育期建立的叶片氮积累量评价模型均达到了极显著性水平。     

鸡红细胞融合最适条件的探讨

目的:探讨快速、有效的细胞融合条件。方法:用鸡红细胞为材料,聚乙二醇(Mw=4000)为诱导剂,诱导鸡红细胞融合。结果:鸡红细胞融合的最适温度为39℃,最适时间为15min。结论:在该条件下,同时用Giemsa染液对融合细胞染色,实验观察效果明显。     

Comparison of the virulence plasmid genomes of two strains of Shigella which lost the ability to bind Congo red

As an enteric pathogen and Gram negative bacte-rium, Shigella possesses high infectivity and leads to serious illness. Since its discovery in 1898 by Shiga, Shigella species have been studied widely. These studies have elucidated the Shigella pathogenicit…     

Characterization of novel microsatellite loci for red clover (Trifolium pratense L.) from enriched genomic libraries

Twenty‐seven polymorphic microsatellite markers were isolated from red clover (Trifolium pratense). Allelic variability and cross‐species amplification were assessed on 24 red clover and eight white clover (Trifolium repens) genotypes. The number of alleles detected in red clover ranged from two to 25. Observed and expected heterozygosities were high with average values of 0.71 and 0.88, respectively. Five of the 27 loci were also successfully amplified from white clover, where two to 13 alleles were detected. These highly polymorphic microsatellite loci provide powerful tools for population genetic studies as well as for marker‐assisted selection in this important forage legume species.     

Development of microsatellite markers in the noxious red tide‐causing algae Heterosigma akashiwo (Raphidophyceae)

We isolated 13 polymorphic microsatellites from the noxious red tide‐causing algae, Heterosigma akashiwo. These loci provide a class of highly variable genetic markers as the number of alleles ranged from three to 12 and the observed and expected heterozygosities ranged from 0.286 to 0.926 and from 0.314 to 0.888, respectively. We consider these loci potentially useful for detailing the genetic structure and gene flow among H. akashiwo populations.     

用粪便形态特征初步研究新疆塔里木马鹿种群年龄和性别

塔里木马鹿分布在干旱地区,是唯一的适应干旱荒漠环境的特殊马鹿亚种之一.目前,塔里木马鹿种群面临着栖息地退缩和片段化的双重影响,这不仅导致了种群数量的锐减,而且也因物种遗传漂变和近亲繁殖的不断增加,进一步加剧其濒危程度.为了有效地保护该物种,全面了解种群结构是至关重要.对塔里木马鹿粪便的长度、宽度、长度/宽度比例和体积等参数进行了测量,并采用判别分析方法划分种群年龄.结果表明,塔里木马鹿粪便形态在不同性别之间有差异,一般雌性的粪便大于雄性(P<0.05).同时根据粪便形态对种群年龄划分为成年雄性、成年雌性和幼体等3个年龄组.     

Elevated spring testosterone increases parasite intensity in male red grouse

The expression of testosterone-dependent sexual traits mightsignal the ability of their bearers to cope with parasite infections.According to the immunocompetence handicap hypothesis (IHH),such signals would be honest because physiological costs oftestosterone, such as a reduced ability to control parasiteinfections, would prevent cheating. We tested whether testosteronewould affect the outcome of a standardized parasite challengein red grouse, using a main parasite of the species, the nematodeTrichostrongylus tenuis. We caught males in spring, removedtheir nematode parasites, and implanted them with testosteroneor empty implants, as controls. After 1 month, they were reinfectedwith a standard dose of infective T. tenuis parasites. Whenchallenged, testosterone males had relatively less globulinrelative to albumin plasma proteins than control males, an indicationthat they had experienced increased physiological stress. Testosterone-treatedmales had significantly more T. tenuis parasites than controlsin the next autumn and also had more coccidia and lost moreweight than controls. Testosterone-treated males neverthelessbenefited from their elevated spring testosterone: they hadbigger sexual ornaments than controls both in spring and autumn,and they tended to have a higher pairing and breeding successthan controls. Our results supported the IHH in showing thatelevated testosterone impaired the ability of males to copewith a standardized challenge by a dominant parasite. Testosteronethus plays a key role in mediating trade-offs between reproductiveactivities and parasite defense, and testosterone-dependentcomb size might honestly signal the ability of red grouse tocontrol T. tenuis infection.     

Resonance light scattering technique for the determination of proteins with Congo red and Triton X-100.

Resonance light scattering (RLS) of Congo red (CR) was greatly enhanced by BSA (HSA) in the presence of Triton X-100 (TX-100). In sodium citrate-HCl buffer (pH 2.7-3.0), the enhanced intensity of resonance light scattering at 360 nm was in proportion to the concentration of proteins [corrected] The linear relationship was obtained between the resonance light scattering intensity and proteins in the range 5.0 x 10(-8)-8.0 x 10(-6) g/mL and 1.0 x 10(-9)-6.0 x 10(-6) g/mL for BSA and HSA, respectively. Their detection limits were 1.4 x 10(-8) g/mL and 2.8 x 10(-10) g/mL (S:N = 3), respectively. Synthetic and actual samples were analysed satisfactorily.     

The phylogeography of palm cockatoos, Probosciger aterrimus, in the dynamic Australo-Papuan region

Aims We aimed to investigate the effects of historical land–sea boundary and vegetation dynamics in the Australo‐Papuan region on the genetic structure of palm cockatoo populations. In doing so, we also sought to clarify the intraspecific taxonomic status of palm cockatoos, and to examine the potential conservation implications of our results. Location New Guinea and northern Australia. Methods We examined mtDNA (domain III, control region) genetic structure in 71 palm cockatoos from 17 locations across their Australo‐Papuan range. Results Twenty polymorphic sites over 242‐base pairs defined 12 haplotypes that were arranged in a 95% confidence parsimony network of six one‐step clades. Half of these were linked in one clade that included birds from eastern New Guinea–Australia, and the other half included birds from western New Guinea. Nested clade analyses revealed strong and significant genetic structure between these two clades. The average nucleotide divergence between eastern and western birds is c. 3.3%. Within the western clade there was a non‐random distribution of haplotypes according to sampling location alone, but the locations did not cluster significantly, probably due to low sample sizes. A non‐random distribution of haplotypes emerged within one of the one‐step clades from the east of the range (once rare haplotypes were removed), although the historic mechanism that may have created this pattern is unclear. The underlying low nucleotide divergence (0.39%) among haplotypes within the eastern clade suggests relatively recent common ancestry. Main conclusions Our results suggest genetic isolation of the eastern and western clades sometime during the Pleistocene. The continual reappearance of land bridges associated with Pleistocene glacio‐eustatic cycles within the eastern part of the range provides an explanation for our results. We suggest that the occurrence of two deep marine troughs maintained a narrow mountainous barrier between eastern and western birds throughout much of the Pleistocene at a time when extensive land bridges formed elsewhere in the species’ range, and that this has maintained their genetic distinctiveness. Our results provide little support for the current accepted subspecies; the western clade is roughly congruent with Probosciger aterrimus goliath (with caveats), but the otherwise unstructured small genetic distances cast considerable doubt on the remaining subspecies. The eastern and western lineages are endemic to each area and should therefore be considered for independent conservation status and management.     

Volume,pH, and ion-content regulation in human red cells: Analysis of transient behavior with an integrated model

Summary A basic mathematical model of human red cells is presented which integrates the charge and nonideal osmotic behavior of hemoglobin and of other impermeant cell solutes with the ion transport properties of the red cell membrane. The computing strategy was designed to predict the behavior of all measurable variables in time in ways that optimize comparison with experimentally determined behavior. The need and applications of such a model are illustrated in three separate examples covering different areas of experimentation in the physiology and pathophysiology of red cells.