鸟类的发声器官及其调控机制

鸟类是具有复杂声行为的动物,其拥有特殊的发声器官--鸣管.尽管鸣禽与非鸣禽的发声特性和发声器官解剖学差异较大,但是两者发声运动控制模式相似.文章综述了近年来鸟类鸣声研究的新进展,重点比较了鸣禽和非鸣禽发声器官的结构功能特点和发声特性调控的异同.作为一种动物模型,鸟类发声系统能为人类语言学习等研究提供借鉴.     

泌乳素及其受体的研究进展

泌乳素(PRL)又名催乳素,是由腺垂体及一些垂体外器官如乳腺、胸腺、脾脏等合成的一种多肽类激素,以内分泌、自分泌、旁分泌的形式发挥作用,其广泛参与机体生长发育、物质代谢、性腺功能调节、应激反应、免疫调节等。泌乳素通过与其受体(PRL receptor,PRLR)在靶细胞的细胞膜表面结合,激活下游的信号转导通路,发挥其生物学作用。由于泌乳素在人体内复杂的生物学效应,泌乳素及其受体又与乳腺癌、泌乳素瘤等多种疾病的发生发展及其预后密切相关。本文就泌乳素发挥效应时对其受体的激活、受体激活后的信号转导机制以及泌乳素同相关疾病的联系进行了综述,相信泌乳素及其受体的研究将为这些疾病的治疗提供重要的方向。     

鸟类的周期性繁殖及其神经内分泌机制

大多数鸟类的繁殖活动具有明显的周期性。影响鸟类繁殖活动的主要因素是光周期 ,传统观点认为可促进繁殖活动的长日照能导致许多鸟类的生殖系统处于光不应状态 ;非光周期因素如食物的多寡、环境温度等其它条件也可影响特殊生活环境中的鸟类的繁殖活动。鸟类的周期性繁殖是环境因素导致神经内分泌过程改变的结果 ,受下丘脑 垂体 性腺轴的调节 ,其中下丘脑的促性腺激素释放激素(GnRH)起重要作用     

实蝇类昆虫生殖行为的研究进展

实蝇是全世界重要的农业害虫,其生殖行为规律对其防治方法的研究具有重要指导意义。本文在文献调研的基础上,对实蝇类昆虫求偶、交配和产卵等行为的最新研究进展进行综述。实蝇类昆虫具有非资源型交配系统,性内、性间选择共同驱动实蝇的性特征进化;同时,实蝇生殖行为受到性信息素、翅信号、物理、化学以及环境等因素的影响。此外,雌虫在交配后会为理想产卵位置发生竞争,而产卵标记信息素起着调节作用。实蝇类昆虫的诸多生殖行为研究结果已成功应用于田间防治,取得了较好的效果。     

鸟类的扩散行为研究进展

扩散是生物个体之间相互远离的单线性运动,是生物的基本特征之一,对种群的分布、动态及遗传结构等方面均有重要影响.扩散有出生扩散和繁殖扩散等主要形式.动物发生扩散的主要原因包括:避免近亲繁殖、减少竞争、改变繁殖地点等.近年来,扩散已经成为鸟类学研究的前沿领域.评述了鸟类扩散行为的性别差异、体质对于扩散的影响,阐述了扩散的基本过程及栖息地选择、长距离扩散等内容,同时介绍了环志标记、无线电遥测、分子生物学等研究鸟类扩散的主要方法.展望了鸟类扩散研究的发展趋势,认为新技术和新方法的应用将成为扩散生态学家关注的重要问题,未来研究将更加重视对鸟类扩散理论问题的探讨,而对鸟类扩散行为的研究成果也会更广泛地应用于濒危物种及其栖息地的保护工作中.     

昆虫迁飞行为及其调控机制

迁飞是昆虫长期适应资源与环境的季节性变化所形成的一种行为策略.迁飞昆虫不仅通过迁飞逃避不良环境,也因其极高的繁殖力确保种群在新的生境中实现快速增长甚至暴发成灾,对整个自然生态系统和农业生态系统影响甚大.本文首先基于部分迁飞概念,描述了迁飞型和居留型个体在形态、行为、生理上的差异,重点介绍了迁飞与生殖的耦合关系,以及诱导迁飞的外界环境因子,最后综述了昆虫迁飞行为调控的分子机制方面的研究进展.从感受不良环境信号到决定迁飞,从起飞、飞行、降落到决定继续迁飞或终止迁飞,这一系列过程受昆虫内分泌、表观等诸多因素的调控,但其背后的分子机制有待深入研究.     

白腰文鸟发声行为的性别差异及其机制

通过声谱分析,研究了５－１２０日龄雌、雄白腰文鸟（Lonchura striata swinhoei)的声谱变化,及该时段３个主要发声控制核团）ＨＶＣ、ＲＡ、Ａrea X)体积、睾丸（睾酮）的相应改变。结果如下：①４５日龄以前,雌雄鸟只能发出简单鸣叫（call),鸣声基本不会鸣唱。②雄性ＨＶＣ,ＲＡ,ＡreaX体积均比雌性大２－６部。３个核团的大小发育不完全一致。各核团的快速生长期与鸣唱学习的主要时段（６０－１２０日龄）不同步,说明核团的个体发育可能不完全受发声行为的影响。③睾丸的充分发育（１２０日龄后）及血液中具有较高的睾酮水平是雄鸟发出成熟鸣唱语句的重要条件。     

自噬及其调控机制的研究进展

自噬是细胞通过一定传输机制将自身细胞质内源性物质,运输到溶酶体中进行降解的过程,在细胞营养物质代谢和清除受损异常的细胞器和蛋白分子等方面,具有非常重要的作用和意义。自噬不仅为细胞自身回收和再利用了生命活动所必需的营养物质及能量,还可为缺氧、饥饿和中毒等极端环境中的细胞生存提供必要的支持条件。因此,自噬无论是在正常的生理状态维持,还是在恶性肿瘤等疾病的病理状态的研究中,都具有十分重要的价值,是目前生物医学研究的重要热点领域之一。     

线粒体超微结构及其调控机制的研究进展

线粒体超微结构是用电子显微镜观察到的精细结构,其可以根据不同能量需求和生理环境变化而变化,对线粒体功能具有关键调节作用.线粒体嵴结构是一种重要的线粒体超微结构,对多种线粒体疾病产生影响.因此,研究线粒体超微结构的调节机制,理解线粒体超微结构功能,对研究线粒体疾病的发病机理及寻找相关疾病的治疗靶点具有重要指导意义.本文详细介绍了线粒体嵴结构的主要调节机制,重点关注线粒体超微结构组成成分、线粒体超微结构对线粒体功能的影响、线粒体超微结构与线粒体疾病关系方面的研究进展,以期为制定更有效的线粒体疾病治疗方案提供理论参考.     

肽聚糖的生物合成及其调控机制研究进展

肽聚糖(peptidoglycan)是细菌细胞壁的重要组成部分,对于维持细胞形态、大小及存活至关重要;同时,肽聚糖是众多常用抗生素的作用靶点。在细菌的正常生长过程中,肽聚糖不断地合成和水解,为了保证细胞壁的完整性,肽聚糖生物合成过程必然受到严谨的时空调控。肽聚糖的生物合成及其调控机制是微生物学中重要的基础研究之一,近年来国内外研究团队在该领域取得了突破性研究进展。基于此,本文综述了肽聚糖的从头合成和循环再利用过程,并重点阐述了肽聚糖合成关键酶——肽聚糖合酶及其调控机制的最新研究进展。最后,本文对未来需要加强研究的方向进行了展望。     

Reproductive exocrine and endocrine profiles and their seasonality in male langur monkeys (Presbytis entellus entellus)

The reproductive exocrine and endocrine profiles in male langurs are reported with an emphasis on seasonality. The animals showed positive response to electroejaculation throughout the year. The sperm concentration varied between 10–383 × 10⁶/ejaculation with wide fluctuations all through the year. No appreciable changes in the motility and percent live sperm were observed throughout the year. The levels of seminal fructose and magnesium remained unchanged throughout the year, while acid phosphatase showed wide fluctuations. Citric acid showed elevation during February and March and LDH showed elevated levels during April and May. The annual range of serum testosterone was 6–34 nMol/l with a peak during July. Cortisol ranged between 575–1587 nMol/l and prolactin ranged between 107–900 mU/l. Wide fluctuations were observed in hormonal levels. No seasonality was exhibited in the seminiferous tubule diameter, nuclear diameter of Sertoli cells and Leydig cells, and the cholesterol, glycogen, and sialic acid contents of testis. None of the parameters studied have shown any correlation with season. The results suggest that the male langurs lack seasonality in their reproductive exocrine and endocrine profiles and thus could be used as model for research in human reproduction.     

Androgen and behavior in the male three-spined stickleback,Gasterosteus aculeatus I.--changes in 11-ketotestosterone levels during the nesting cycle

Circulating 11-ketotestosterone (11KT) levels are higher during the courtship phase than during the later parental phase in a number of male teleosts. The present study describes the temporal changes in 11KT levels and their relationships to changes in courtship behavior, after different number of spawnings, over the nesting cycle of the male three-spined stickleback, Gasterosteus aculeatus, a small teleost showing pronounced paternal behavior. Plasma 11KT levels, measured by radioimmunoassay, were approximately 34 times higher during the initial courtship phase than at the end of the following parental phase in spawned males. In addition, males that spawned with three or more females on a single day showed an earlier decline in 11KT levels and in courtship behavior compared to males that were only allowed to spawn with a single female. Plasma 11KT levels remained high in males not allowed to spawn.     

Seasonal and sexual dimorphisms in the green anole forebrain

During the breeding season, male green anole lizards extend a throat fan (dewlap) in courtship. This behavior is facilitated by testosterone (T). Females extend a much smaller dewlap less often, even with the same dose of T. During the nonbreeding season when T is low, dewlap extension is reduced. To determine if parallels exist between structure and function, we investigated neuron soma size and density in the preoptic area (POA) and ventromedial nucleus of the amygdala (AMY), which are involved in the display behavior, in breeding and nonbreeding males and females. Cells from breeding animals were larger than cells from nonbreeding animals, but they were not sexually dimorphic. No significant effects existed in neuron density. This experiment indicates that portions of the anole forebrain important for sexual behavior are plastic and might be influenced by seasonal changes in steroid hormones. To investigate whether T can reverse the seasonal difference in soma size in both sexes, gonadectomized nonbreeding anoles were implanted with an empty or T propionate-filled capsule; animals were also tested for male-typical courtship behavior. Males and females treated with T had higher rates of dewlap extension, but across treatment groups these rates were greater in males. Neuron soma size in the POA and AMY was larger in males than females, but no effects of treatment were detected. Taken together, the results indicate that T can stimulate behavior in the nonbreeding season and suggest that a dissociation exists between the regulation of the courtship display and soma size of relevant brain regions.     

慢性低氧对雄性大鼠血浆皮质酮及睾酮水平的影响

目的:研究低氧对雄性大鼠性腺及相关激素水平的影响。方法:分别检测3km、5km及杭州海拔水平雄性大鼠睾丸和附睾指数、血浆皮质酮和睾酮水平。结果:3km组体重、睾酮含量均显著下降,睾丸指数、血浆皮质酮显著上升;5km组体重、附睾指数和睾酮含量均显著下降,皮质酮含量显著上升。结论:慢性低氧能显著影响雄性成年大鼠性腺及血浆睾酮水平,该结果显示哺乳动物在慢性低氧条件下生殖内分泌功能呈现抑制状态。     

Testosterone and prolactin are associated with emotional responses to infant cries in new fathers

To determine the responsiveness of new fathers and non-fathers toward infant cues, we exposed fathers and non-fathers to infant cries and to control stimuli and we measured affective, heart-rate, and endocrine responses, including salivary testosterone and cortisol and plasma prolactin concentrations prior to and after cry presentations. We found that (1) fathers hearing the cry stimuli felt more sympathetic and more alert compared to groups who did not hear the cries or to non-fathers who heard the cries; (2) fathers and non-fathers with lower testosterone levels had higher sympathy and/or need to respond to the infant cries than fathers with higher testosterone levels; (3) fathers with higher, as opposed to lower, prolactin levels were also more alert and more positive in response to the cries; (4) fathers hearing the cry stimuli showed greater percentage increase in testosterone than fathers not hearing the cry stimuli; (5) experienced fathers hearing the cries showed a greater percentage increase in prolactin levels compared to first-time fathers or to any group of fathers hearing control stimuli; finally, (6) partial correlations with parity and experience entered as a covariates indicated that both experience and testosterone contributed to the variance in fathers' affective responses to infant cries. Taken together, these results indicate that, as with a number of other biparental species, human fathers are more responsive to infant cues than are non-fathers and fathers' responses to infant cues are related to both hormones and to caregiving experience.     

Observations on the reproductive biology of the land tortoises Geochelone emys and Geochelone yniphora in the Honolulu Zoo

Captive reproduction of the Burmese brown tortoise (Geochelone emys) has occurred repeatedly over a five-year period in the Honolulu Zoo. Maximum clutch size (51 eggs) exceeds that reported for other members of the Testudinidae. Nesting behavior in G emys includes construction of a large leaf-litter mound. Collection of nest-building material is accomplished by “back-sweeping” of ground litter within a distance of up to 4 m from the nest site. The nesting female assumes a “nest-guarding” behavior for a period of 2–3 days following egg laying. Eggs incubated artificially hatched in 63–84 days, with egg fertility at 78–84%. One hundred and three G emys were successfully hatched and reared during the period 1978–82. A colony of endangered Madagascar angulated tortoises (Geochelone yniphora) have been maintained at the Honolulu Zoo since 1971. Courtship and mating behavior is similar to that described for the consubgeneric G radiata. Distinctive male “hooking” behavior during courtship in G yniphora is related to the exaggerated epiplastron development in this species. Egg laying has occurred repeatedly in the G yniphora colony since 1979 (mean clutch size = 4.2; N = 6) although no eggs have yet proved fertile.     

Hormonal and behavioral responses of starlings during a confrontation with males or females at nest boxes during the reproductive season

We investigated in an aviary experiment the behavioral and hormonal responses of European starlings (Sturnus vulgaris) that were moved from a same sex group to an aviary containing either a nest box alone, a nest box and another male, or a nest box and a female. Luteinizing hormone (LH) and testosterone (T) levels increased significantly and independently of the situation, suggesting that nest boxes were the most important stimulus affecting the levels of these hormones. Some birds occupied more than two boxes (winners), and others a single or no box (losers). Levels of T increased less in males that did not acquire a nest box. However, the increase in LH was similar in all males after the test. Singing was positively correlated with T levels. Winners started singing earlier and sang more during a contest than losers. In the presence of females LH increased more in winners than in losers, while the increase in T was similar in both groups. In females, there was no increase in T but LH increased in the presence of males. Levels were higher in females paired with winners than in females paired with losers. Finally, winners advertised their nest boxes more frequently than losers. These results indicate that within a relatively short time frame levels of LH and T increase following the transfer from a flock to a territorial situation and can react independently from each other depending on reproductive circumstances. For males, the possession of a nest box and, for females, the qualities of the male seemed to be the most important factors stimulating reproduction.     

Influence of previous sexual experience and post-emergence rearing conditions on the mating behavior ofChryseida bennetti

Experiments were carried out to study the possible effects of a (first) sexual experience and prior rearing conditions on the subsequent sexual behavior ofChryseida bennetti (Hymenoptera: Eurytomidae), an ectoparasitoid of the bean weevilAcanthoscelides obtectus (Say) (Coleoptera: Bruchidae). A clear reduction in latency before male courtship was observed in experienced males. Multiple matings were performed both by naive and experienced males. A tendency to reduce the post-mating courtship behavior duration was observed in experienced males, although this reduction was not significant. Rearing conditions also seem to influence the mating behavior of this species: the number of copulations (with the same female) was reduced when males were reared in groups. On the contrary, isolated males performed multiple matings with both grouped and isolated females, although they mated 3 times only with isolated ones. Again, a reduction of the duration of the post-mating courtship behavior was observed both in grouped males and grouped or isolated females. It seems likely that males that have been reared in groups benefit from a certain influence of social experience that is reflected on their later sexual behavior.     

Individual variation and the endocrine regulation of behaviour and physiology in birds: a cellular/molecular perspective

Investigations of the cellular and molecular mechanisms of physiology and behaviour have generally avoided attempts to explain individual differences. The goal has rather been to discover general processes. However, understanding the causes of individual variation in many phenomena of interest to avian eco-physiologists will require a consideration of such mechanisms. For example, in birds, changes in plasma concentrations of steroid hormones are important in the activation of social behaviours related to reproduction and aggression. Attempts to explain individual variation in these behaviours as a function of variation in plasma hormone concentrations have generally failed. Cellular variables related to the effectiveness of steroid hormone have been useful in some cases. Steroid hormone target sensitivity can be affected by variables such as metabolizing enzyme activity, hormone receptor expression as well as receptor cofactor expression. At present, no general theory has emerged that might provide a clear guidance when trying to explain individual variability in birds or in any other group of vertebrates. One strategy is to learn from studies of large units of intraspecific variation such as population or sex differences to provide ideas about variables that might be important in explaining individual variation. This approach along with the use of newly developed molecular genetic tools represents a promising avenue for avian eco-physiologists to pursue.