通过光谱与视觉模型研究动物体色

体色是动物进行种内和种间信息交流的重要性状特征。与人类的三基色视觉系统不同,许多动物都具有四面体颜色系统,包括人眼无法探测的紫外光区域。动物体色是动物生态学中的一项重要研究内容,以人类主观角度对动物体色进行描述和分类,可能会导致研究结果的偏差,甚至得出错误结论。该文以赤红山椒鸟(Pericrocotus flammeus)为实例,通过分段光谱分析,对动物体色的色调、色度、亮度以及各波段的亮度进行量化;通过构建先进的动物视觉模型以考虑环境光线的影响和动物视网膜对不同波段光线的敏感度和捕获能力,同时将颜色斑块直观投射在四面体颜色空间和罗宾逊投影中,以量化颜色跨度和空间容量等参数,真正实现从动物的视觉角度分析动物体色。     

黄色鲤、蓝色鲤、红色鲤杂交的体色及鳞被遗传特性

进行黄色鲤(Cyprinus carpio)、蓝色鲤及红色鲤的自交和杂交试验,统计分析子代的体色及鳞被分离情况。结果表明,实验选择的亲本,红色鲤的体色和鳞被都是纯合基因型;蓝色鲤的体色是纯合型,鳞被是杂合型;黄色鲤的体色和鳞被都是杂合型。它们彼此杂交的体色遗传规律较复杂,子代中不但具有亲本的红、黄、蓝体色,还出现了其他色彩,如青灰色、白色、青黄色和蓝白色,部分红色个体的背部还呈暗黑色。同时,实验还观察了不同体色鲤的鳞片、鳍条色素细胞分布情况,分析和讨论了鲤杂交的体色遗传特性。     

龟鳖动物体色研究进展

体色是动物重要的形态特征,具有信息传递、体温调节和反捕食等功能.动物体色的研究近2个世纪,已在进化和适应方面取得了较大突破,开拓了行为生态学研究的新方向,极大地促进了应用心理学、计算机科学和军事等应用学科的发展.在目前已知的356种龟鳖动物中,体色多样,但由于其特殊的甲壳结构,龟鳖动物体色研究起步较晚,各种体色的生态适...     

动物的体色

几乎所有动物都具有一定的体色。动物体色具有多方面的生物学意义，如吸引配偶、警戒敌人、隐蔽自身等。研究动物的体色对研究动物的行为极为重要。     

几丁质及其衍生物对胆固醇代谢的影响

几丁质(chitin)又称甲壳素,化学名称为N-乙酰氨基葡萄糖多聚体,是一种天然的多糖类纤维素。几丁质脱乙酰基即为几丁糖(chitosan)。几丁质、几丁糖及其衍生物具有非常良好的生物安全性,而且可以自然降解。由于其独特的生物化学性能,几丁质、几丁糖及其衍生物已被证实具有抑制肿瘤细胞生长、抗粘连、缓释药物、降胆固醇、调节凝血功能和促进创面愈合等作用。国内已有关于其抑制肿瘤细胞生长、抗粘连、缓释药物     

保护色、警戒色、拟态的区分方法

保护色、警戒色、拟态是生物在长期进化过程中形成的与环境相适应的典型特征。保护色是动物通过伪装使得自己身体体色和斑点与背景环境相接近进而隐蔽起来 ,使得不易被天敌发现的体色。特点 :体色与外界环境的优势色彩保持一致。警戒色是指某些有恶臭或毒刺的动物所具有的鲜艳的色彩和斑纹 ,与保护色的隐蔽性相反 ,与环境的优势色彩大相径庭。特点是 :色彩鲜艳醒目 ,容易识别 ,一般动物有特殊的“本事”,能够对敌害起到预先示警的作用 ,因而有利于动物的自我保护。。拟态是指 1个味道很好 ,可食的物种在进化过程中 ,采纳有毒或有伤害性物种…     

烟曲霉素及其衍生物生物活性研究进展

烟曲霉素是一种从烟曲霉菌(Aspergillus fumigatus)提取液中分离出来的具有多种生物活性的抗生素。因其具有多种生物活性,已有多种衍生物被合成,并被应用于多种领域。主要介绍了烟曲霉素及其3种衍生物Fumagillin B、TNP-470和CKD-732的分子结构及生物活性,并总结了烟曲霉素及其衍生物在治疗蜜蜂和鱼类的微孢子虫病以及人类癌症和肥胖症等方面的作用。     

蛤蚧地理变异的初步研究

历代本草和国家《药典》都没有蛤蚧品种分化的记载。动物分类上一直把蛤蚧的体色变异看成是居住环境所致。我们在药用动物资源调查中发现蛤蚧有明显的地理变异。产自我国广东、广西和云南南部及越南、缅甸北部的蛤蚧体型较细,体色较深,色斑较杂,称之为黑蛤蚧;而东南亚及南亚大部分地区出产的蛤蚧则体型粗壮,体重较大,体色较浅,具有醒目的红色斑点,故称之为红蛤蚧或泰国哈蚧。二者的地理分布不重叠,市场售价差异甚大。     

黑色素及其相关基因的研究进展

黑色素对动物体色的形成起重要的作用。对黑色素的本质、功能以及生成机理做了全面的总结,并归纳了一些影响动物皮肤颜色和毛色的主要基因及其研究现状。     

酿酒酵母合成木栓酮及其衍生物的研究现状及展望

木栓酮及其衍生物在植物中普遍存在且种类繁多,具有丰富的生理药理学活性。木栓酮衍生物是以木栓酮为骨架经细胞色素氧化酶P450(cytochromeP450,CYP450)及UDP葡萄糖醛酸转移酶(UDP-glucuronosyltransferase, UGT)修饰而来。植物中天然木栓酮及其衍生物的含量极低,传统的萃取分离和化学合成效率低、能耗高且污染环境,因此,利用酿酒酵母作为宿主菌生产木栓酮及其衍生物是一种高效且环保的策略。本文从增加前体含量、提高酶活性和产物合成的亚细胞定位等方面介绍并展望了木栓酮在酿酒酵母中高效生产的策略,并介绍了目前几种常见的木栓酮衍生物研究现状,从根据碳骨架相似性挖掘CYP450、蛋白质工程改造CYP450和合成代谢基因簇的挖掘等方面展望了木栓酮衍生物的合成途径解析的新思路。     

Oculocutaneous albinism type 1: the last 100 years

Research on human albinism has been central to many of the major discoveries in human genetics. These include the first evidence that Mendel's rules of genetic segregation apply to humans, first published in 1903. Contrary to initial thought that albinism is caused by mutations in a single gene, we now know that the genetics of albinism are complex. The complexity of albinism was hinted at, in early publications, but has only recently been fully appreciated with the advent of molecular techniques. Currently, 12 different genes have been identified, that when mutated, result in a different type of albinism. Oculocutaneous albinism type 1 (OCA1), resulting from mutations of the tyrosinase gene, is genetically and biochemically the best understood type of albinism. Though much of the research in albinism has involved OCA1, there are many unanswered questions about OCA1 and albinism, in general. The next 100 yr should still provide many surprises as did the first 100 yr.     

Oculocutaneous Albinism Type 1: The Last 100 Years

Research on human albinism has been central to many of the major discoveries in human genetics. These include the first evidence that Mendel's rules of genetic segregation apply to humans, first published in 1903. Contrary to initial thought that albinism is caused by mutations in a single gene, we now know that the genetics of albinism are complex. The complexity of albinism was hinted at, in early publications, but has only recently been fully appreciated with the advent of molecular techniques. Currently, 12 different genes have been identified, that when mutated, result in a different type of albinism. Oculocutaneous albinism type 1 (OCA1), resulting from mutations of the tyrosinase gene, is genetically and biochemically the best understood type of albinism. Though much of the research in albinism has involved OCA1, there are many unanswered questions about OCA1 and albinism, in general. The next 100 yr should still provide many surprises as did the first 100 yr.     

广东发现二种局部白化蝙蝠

动物的白化主要是由于动物的黑色素细胞缺乏或者黑色素生成发生障碍所导致的一种体色异常现象。白化现象有完全白化和局部白化两种,部分白化指皮肤、毛发等的局部白化;完全白化是指由于完全缺少黑色素,皮肤和毛发白色,眼睛红色,可     

ALBINISM AND PHENOTYPE OF BARN SWALLOWS (HIRUNDO RUSTICA) FROM CHERNOBYL

Abstract The effects of mutation on phenotypic expression are supposed to be mainly deleterious because mutations disrupt the expression of genes that function relatively well under current environmental conditions. Thus, mutations are assumed to give rise to deviant phenotypes that are generally selected against. Radioactive contamination in the Chernobyl region of Ukraine is associated with a significant increase by a factor two to 10 in mutation rate in microsatellite markers of the barn swallow, Hirundo rustica. Barn swallows from Chernobyl had a temporally constant, elevated frequency of partial albinism compared to the situation before radioactive contamination and compared to birds from a control area. Albinism disproportionately affected the carotenoid‐based plumage of the head, suggesting that carotenoid metabolism is particularly susceptible to the effects of radiation. Individuals with partially albinistic plumage had, on average, lower mean phenotypic values than other birds, and this was particularly the case for males. Furthermore, differences in phenotypic variation, as determined using Levene's test, were significantly larger in partial albinos compared to nonalbinos in males, but not in females, even though the null expectation would be the opposite due to the lower mean phenotypic values of partial albinos. Although small phenotypes were commonly associated with germline mutations, there was no general decrease in overall body size during the period 1991–2000, implying that small individuals were selected against. Because partial albinism is disfavored by natural selection, the effects of mutations are deleterious, giving rise to a balance between mutation and selection.     

Mutations at critical N-glycosylation sites reduce tyrosinase activity by altering folding and quality control

Tyrosinase is a copper-containing enzyme that regulates melanin biosynthesis in mammals. Mutations at a single N-glycosylation sequon of tyrosinase have been reported to be responsible for oculocutaneous albinism type IA in humans, characterized by inactive tyrosinase and the total absence of pigmentation. To probe the role that each N-glycosylation site plays in the synthesis of biologically active tyrosinase, we analyzed the calnexin mediated folding of tyrosinase N-glycosylation mutants. We have determined that four of the six potential N-glycosylation sites, including that associated with albinism, are occupied. Analysis of the folding pathway and activity of 15 tyrosinase mutants lacking one or more of the occupied N-glycosylation sites shows that glycans at any two N-glycosylation sites are sufficient to interact with calnexin and give partial activity, but a specific pair of sites (Asn(86) and Asn(371)) is required for full activity. The mutants with less than two N-glycosylation sites do not interact with calnexin and show a complete absence of enzyme activity. Copper analysis of selected mutants suggests that the observed partial activity is due to two populations with differential copper content. By correlating the degree of folding with the activity of tyrosinase, we propose a local folding mechanism for tyrosinase that can explain the mechanism of inactivation of tyrosinase N-glycosylation mutants found in certain pigmentation disorders.     

Albinism in Plants: A Major Bottleneck in Wide Hybridization,Androgenesis and Doubled Haploid Culture

Albinism is a common problem encountered in interspecific crosses and tissue culture experiments including anther culture and generation of doubled haploids. It is characterized by partial or complete loss of chlorophyll pigments and incomplete differentiation of chloroplast membranes. This in turn impairs photosynthesis and the plants eventually die at a young stage without reaching maturity. Environmental conditions such as light, temperature, media composition and culture conditions play some role in determining the frequency of albino plant formation. Genetic factors are even more important, and are major determinants in albinism. Genetic studies in different crops show that it is a recessive trait governed by many loci. Both the nuclear and chloroplast genomes affect albinism and incompatibilities between the two are a probable cause of many pigment defects in hybrid progenies. Such incompatibility has been reported in a large number of angiosperms. The mechanisms behind these incompatibilities are poorly understood. Studies of plastid DNA inheritance together with observations using electron microscopy have established that the transmission of plastids can be maternal, paternal or biparental, even within the same genus, especially following wide crosses; contrary to the widespread belief that plastids are almost always transmitted from the maternal parent. Albinism has been overcome in some crop species through somatic hybridization and development of cybrids (cytoplasmic hybrids). However, the strict requirement of efficient protoplast regeneration is a major limitation of these techniques. This review focuses on albinism following interspecific crosses or development of doubled haploids facilitated by tissue culture experiments, underlying mechanisms, and the possibilities for dealing with this important biotechnological limitation.     

NGS‐based targeted resequencing identified rare subtypes of albinism: Providing accurate molecular diagnosis for Japanese patients with albinism

Albinism, which is commonly inherited as an autosomal recessive trait, is characterized by a reduction or absence of melanin in the eyes, skin, and hair. To date, more than 20 causal genes for albinism have been identified; thus, the accurate diagnosis of albinism requires next‐generation sequencing (NGS). In this study, we analyzed 46 patients who tested negative for oculocutaneous albinism (OCA)1–4 and Hermansky‐Pudlak syndrome (HPS)1 based on conventional analysis, in addition to 28 new Japanese patients, using NGS‐based targeted resequencing. We identified a genetic background for albinism in 18 of the 46 patients (39%), who were previously tested negative according to the conventional analysis. In addition, we unveiled a genetic predisposition toward albinism in 23 of the 28 new patients (82%). We identified six patients with rare subtypes of albinism, including HPS3, HPS4, and HPS6, and found 12 novel pathological mutations in albinism‐related genes. Furthermore, most patients who were not diagnosed with albinism by the NGS analysis showed mild manifestations of albinism without apparent eye symptoms and harbored only one heterozygous mutation, occasionally in combination with skin‐color associated gene variants.     

Preliminary Studies on Cytoplasmic Inheritance and Variation of Azolla

By investigating the variance of Azolla leaf colour of F1 generation obtained from negative and positive crossing of Azolla between two species (Azolla filiculoides × A. microphylla, A. filiculoides × A. mescicana) and two subgenus (A. filiculoides × A. imbricata), it was revealed that the albinism of the hybrid F1 generation was variation resulting from maternal cytoplasmic inheritance, when A. filiculoide was used as female parent. Electron microscopic observation demonstrated abnormal development of plastid in the albino sporeling. The cell of light green seedling contained both normal and abnormal plastid. Both were probably related to variation in the plastid genotype. Significant difference occurred in the degree and freguency of albinism from various crossing forms, and such change had its vegularity in accord with the variation of the nuclear genotype. The results speculated that albinism were also closely related to the nuclear genotype.     

广西发现局部白化中蹄蝠幼仔一例

2008年6月,在广西桂林市郊冷水塘村发现一例白化雌性中蹄蝠(Hipposideros larvatus)幼仔,属局部白化现象,白化区域包括背部中线靠右侧的小区域以及尾膜边缘和右足.该中蹄蝠幼仔前臂长49.1mm,体重10.8 g.     

Hopi Indians, "cultural" selection,and albinism

The incidence of albinism in Hopi Indians has been estimated as approximately 1 in 200 individuals. It has been suggested that "cultural" selection as the result of a mating advantage of males with albinism has been important in the maintenance of this high incidence. To examine this hypothesis quantitatively, a model that includes male-mating advantage, mutation, and viability selection is analyzed. In order to play an important role in the maintenance of the high incidence of albinism, the necessary mating advantage of males with albinism appears unrealistically high. However, if the extent of viability selection against individuals with albinism is not as large as previously assumed, the necessary amount of mating advantage is not as high. Other related aspects are also discussed here, such as the type of albinism in Hopi Indians and its impact, the conditions for a polymorphism with male-mating advantage and viability selection, and the time necessary to change the incidence of albinism either by the relaxation or institution of male-mating advantage.