大鼠微量元素添加剂配方研究

大鼠微量元素添加剂配方研究刘学旭,程朝辉,张水蓉华西医科大学实验动物中心成都６１００４１国内外研究表明,微量元素对大鼠生长、繁殖性能和免疫功能均有较大的影响￣［１］。但以天然原粮为日粮的大鼠饲料中是否需要添加微量元素,文献报道不尽一致￣［２］。本试验...     

不同倍性小麦和玉米不同群体杂交诱导小麦单倍体的研究

自从Ｚｅｎｋｔｅｌｅｒ等［１］首先报道了小麦×玉米受精现象以来,许多学者对六倍体普通小麦与玉米杂交进行了广泛的研究,获得单倍体的普通小麦,并筛选到一些杂交亲和性较高的亲本材料［２］。但四倍体小麦与玉米杂交研究报道较少。ＯＤｏｎｏｕｇｈｕｅ等用四倍体小麦与玉米杂交获得单倍体胚［３］。随后,Ａｍｒａｎｉ等［４］和孙敬三等［５］利用这一方法相继获得四倍体小麦的单倍体苗。本文报道了不同倍性的小麦基因型与玉米不同群体杂交对诱导小麦单倍体的影响１　材料和方法１．１　亲本材料用作母本的二倍体小麦有一粒小麦（…     

摄食,体重和光照条件对罗氏沼虾幼体氧代谢的影响

水生动物的代谢耗能在能量支出中占有重要的比例,且代谢耗能及其比例的大小受各种生态因子的影响,因此,研究动物的代谢及其影响因素是生物能量学的一个重要课题。有关鱼类代谢的研究很多且已有全面的综述性报道［１］,而有关甲壳类,特别是虾类幼体代谢方面的专题研究...     

温度对棉铃虫滞育的影响

在前人研究的基础上［１,２］,我们已经了解到光照和温度乃是影响和决定棉铃虫是否进入滞育状态的关键外界环境因子。但光照和温度,哪一个在决定棉铃虫的滞育中起着更关键的主导地位,则无文献述及,为此,我们设计了如下几个实验,试图来解答这个问题以及进一步了解温度对棉铃虫滞育的影响。１材料与方法１．１实验昆虫虫源由中国科学院动物研究所何忠教授提供,系采自河南郑州,在２５℃、每天光照１６小时的条件下用人工饲料［１］饲养繁殖。滞育的棉铃虫在２０℃、每天光照１０小时的条件下饲养,其滞育率可达１００％;非滞育的棉铃…     

光系统Ⅱ反应中心D1/D2/Cytb559复合物中去镁叶绿素a的光照破坏

高等植物在强光照射下,光合作用受到抑制。光抑制的分子机理已成为目前光合作用研究中最活跃的研究领域之一［１］。由于叶绿体内色素和蛋白分子很多,其中包含有许多与光破坏不直接相关的组分,因此很难确定具体哪个分子受到破坏。用只含少数色素和多肽分子的光系统Ⅱ（ＰＳⅡ）反应中心Ｄ１／Ｄ２／Ｃｙｔｂ５５９复合物［２］可以解决这个问题,现已证明用光照射该复合物能引起原初电子供体Ｐ６８０的破坏［３,４］,并且是一个多步反应［５］,同时还发现有组氨酸残基的光照破坏［６,７］,当存在电子受体的情况下反应中心内部β－ｃ…     

黄鳝松果腺复合体的超显微结构研究

鱼类松果腺能将其感受到的光信息以及脑部神经信号转换成激素分泌,研究表明,褪黑激素是松果腺影响生物性腺发育的主要分泌物［１,２］。因此推测松果腺及其分泌物褪黑激素可能参与调节黄鳝的性转变进程。作者曾利用外源褪黑激素注射鱼体的实验结果表明,褪黑激素对黄鳝的性腺发育存在着剂量依存的促进与抑制的双重调节作用［３］。本文首次证实黄鳝脑中松果腺复合体（ＰｉｎｅａｌＣｏｍｐｌｅｘ）的存在,并对其超显微结构进行了研究。１材料与方法１．１实验动物　黄鳝（Ｍｏｎｏｐｔｅｒｕｓ　ａｌｂｕｓ　Ｚｕｉｅｗ）：体长２８－４…     

不同组分脂肪含量对SD大鼠生产性能的影响

脂肪是大鼠日粮中最普通的营养成分之一,除作为必需脂肪酸（ＥＦＡ）的来源外,在利用日粮脂溶性维生素方面还有作用［１］。据报道大鼠喂以含１０％和１１％的脂肪日粮能维持极好的繁殖和泌乳［１］。另有报道认为当大鼠日粮脂肪为３％到８％时,繁殖和泌乳差异不大［１］。Ｓｗｉｆｔ和Ｂｌａｃｋ认为大鼠对３０％脂肪日粮比２０％脂肪的日粮接受性好。另外不同来源的脂肪其脂肪酸组分差异较大,因而确定日粮最佳脂肪浓度的证据不明确。为此,本文主要探索不同脂肪组分及含量对ＳＤ大鼠繁殖性能和生长性能的影响。１　材料与方法１－１　…     

光照对水生动物行为的影响

水生动物的行为受外界环境因素的影响很大，光作为自然界中重要的生态因子，对动物行为的影响极为明显。对于光照的变化，动物能调节自身作出适当的行为反应。本文主要对国外这方面的研究报道作了总结。１光照对水生动物趋光行为的影响动物的趋光性与其视力有关，因而在不...     

丹顶鹤与白枕鹤的领域比较

有７种濒危鹤类受到现代人的威胁［２０］,丹顶鹤（Ｇｒｕｓｊａｐｏｎｅｎｓｉｓ）和白枕鹤（Ｇｒｕｓｖｉｐｉｏ）是其中两种,分别为我国的Ⅰ、Ⅱ级保护动物。在中国丹顶鹤主要在黑龙江省的乌裕尔河下游和三江平原等地繁殖,数量在４８２～５０２之间［７］。吉林省的向海也有４０余只繁殖鹤［８,９］。它们在长江中下游的江苏盐城、高邮湖、洪泽湖,安徽省的城东湖、石臼湖、菜子湖越冬［５］。白枕鹤繁殖区在中国东北的乌裕尔河下游、向海、达里诺尔湖以及乌苏里江以东俄罗斯的沿海边区［２０］。我国已知的繁殖区内数量不多［１］,…     

灰喜鹊的繁殖生态和巢位选择：Ⅱ.巢位选择

灰喜鹊在吉林省梅河口市海龙水库地区是常见的留鸟。利用灰喜鹊防治森林虫害已经取得了一定的效果［１～３］,但对灰喜鹊的繁殖习性,生态规律及食性的研究还尚少［４～７］,对灰喜鹊巢位选择的研究亦属空白。因此,本文在吉林省环保局“梅河口市海龙水库水源涵养林保护...     

Photoperiod as a reproductive cue in the marsupial genus Antechinus: ecological and evolutionary consequences

Species in the Australian marsupial genus Antechinus exhibit a short annual mating period which is concluded by the abrupt death of all males. The timing of the annual rut within each of the ten described species varies little from year to year at any given locality, but for some species can differ by up to four months between locations. To determine the influence of photoperiod in regulating the precise interannual synchrony of mating and ovulation, we first investigated populations of each species at over 300 localities throughout their geographical ranges to identify the time of reproduction. We then compared the absolute photoperiod and the rate of change of photoperiod prevailing at the time of reproduction in all population localities. A different, and characteristic, rate of change of photoperiod was correlated strongly with the reproductive timing of four species; there was probably a correlation with reproduction in four more species, but sample sizes were small. For two species, there was no obvious photoperiodic correlation with time of reproduction. There was no evidence that absolute photoperiod or ambient temperature explained the synchrony or narrow timespan of reproduction among any species of Antechinus . Different species-specific ovulatory responses to photoperiod appear to separate the timing of reproduction in sympatric species, with the larger member of species pairs usually breeding first. We suggest that photoperiodic cues (1) allow females to produce young during seasons when food is most reliable and abundant and their energetic demands are maximal; (2) facilitate allochronic isolation between sympatric congeners, and (3) maximize body size differences and hence ecological separation between species.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 365–379.     

Inhibition of reproductive maturation and somatic growth of Fischer 344 rats by photoperiods shorter than L14:D10 and by gradually decreasing photoperiod

Photoperiod is the major regulator of reproduction in temperate-zone mammals. Laboratory rats are generally considered to be nonphotoresponsive, but young male Fischer 344 (F344) rats have a uniquely robust response to short photoperiods of 8 h of light. Rats transferred at weaning from a photoperiod of 16 h to photoperiods of < 14 h of light slowed in both reproductive development and somatic growth rate. Those in photoperiods < 13 h of light underwent the strongest responses. The critical photoperiod of F344 rats can be defined as 13.5 h of light, but photoperiods of 相似文献   

The endocrine control of reproduction in Nereidae: a new multi-hormonal model with implications for their functional role in a changing environment

Nereidae are vital to the functioning of estuarine ecosystems and are major components in the diets of over-wintering birds and commercial fish. They use environmental cues to synchronize reproduction. Photoperiod is the proximate cue, initiating vitellogenesis in a temperature-compensated process. The prevailing paradigm in Nereidae is of a single ‘juvenile’ hormone controlling growth and reproduction. However, a new multi-hormone model is presented here that integrates the environmental and endocrine control of reproduction. This is supported by evidence from in vitro bioassays. The juvenile hormone is shown to be heat stable and cross reactive between species. In addition, a second neuro-hormone, identified here as a gonadotrophic hormone, is shown to be present in mature females and is found to promote oocyte growth. Furthermore, dopamine and melatonin appear to switch off the juvenile hormone while serotonin and oxytocin promote oocyte growth. Global warming is likely to uncouple the phase relationship between temperature and photoperiod, with significant consequences for Nereidae that use photoperiod to cue reproduction during the winter in northern latitudes. Genotypic adaptation of the photoperiodic response may be possible, but significant impacts on fecundity, spawning success and recruitment are likely in response to short-term extreme events. Endocrine-disrupting chemicals may also impact on putative steroid hormone pathways in Nereidae with similar consequences. These impacts may have significant implications for the functional role of Nereidae and highlight the importance of comparative endocrinology studies in these and other invertebrates.     

FIELD AND CULTURE STUDIES ON GROWTH AND REPRODUCTION OF CALLITHAMNION BYSSOIDES (RHODOPHYTA,CERAMIALES) IN NORTH CAROLINA1,2

The life history of Callithamnion byssoides Arnott ex Harv. in Hook. from North Carolina is shown to be of the Polysiphonia-type. Cross-gradient light-temperature culture in 8:16 and 14:10 LD cycles was utilized to investigate the effects of light intensity, temperature and day-length on growth and reproduction. Carposporophyte and tetrasporangium development were controlled by total light energy rather than photoperiod. Results of these studies explain the observed seasonal periodicity of growth and reproduction on the North Carolina coast. Variations between these results and previously published data for this species in Texas are explained in terms of ecotypic differentiation.     

A photoperiod gene regulates vitellogenesis in Lymnaea peregra (Mollusca: Gastropoda: Pulmonata)

Summary

Populations of the fresh-water snail Lymnaea peregra from different localities vary in their capacity to lay eggs, responding either to long day or to short day photoperiods. These responses are genetically determined by a single gene locus with the long day allele dominant over the short day allele. Although previtellogenic stages of oogenesis are not affected by an inhibitory photoperiod, vitellogenesis is essentially shut down. The volumes of the dorsal bodies, which are endocrine organs that mediate vitellogenesis, are significantly smaller in snails maintained in an inhibitory photoperiod. Implantation of cerebral ganglia with attached dorsal bodies, both from egg laying animals and from dormant animals that have the potential to lay eggs in the postoperative photoperiod, into snails that were inhibited by insufficient photoperiod resulted in a significant increase in vitellogenesis in the ovotestes of the hosts. An increase in host dorsal body volume was also observed. The photoperiod gene appears to control some aspect of the cerebral ganglion that activates the dorsal body to produce a hormone that stimulates vitellogenesis in the ovotestes. Photoperiodic control of reproduction may be a factor contributing to the diverse life history strategies observed in this species.     

Long-day inhibition of reproduction and circadian photogonadosensitivity in Zembra Island wild rabbits (Oryctolagus cuniculus).

We investigated the effects of photoperiod on testicular activity in wild rabbits (Oryctolagus cuniculus) captured on Zembra Island (North Tunisia) and maintained in experimental photoperiodic conditions. Sexually inactive animals were subjected to alternate 3-mo periods of short days (8L:16D) and long days (16L:8D) for 1 yr. Testicular activity increased significantly and then decreased to levels equivalent to or lower than those measured during sexual quiescence after 1 mo of 8L:16D or 16L:8D, respectively. Eight groups of sexually active animals were also exposed to 8L:16D for 60 days. The light phase was divided into two photofractions (7.5 and 0.5 h). The short photofraction interrupted the dark phase 9.5-18.5 h after the beginning of the main photofraction. Testicular activity was inhibited if the short photofraction interrupted the dark phase 12.5 h or more after the beginning of the main photofraction. These results clearly confirm that photoperiod affects reproduction in this species: Short days stimulate reproduction, whereas long days inhibit it. The asymmetric pattern of skeleton photoperiods used demonstrated the existence of a circadian rhythm for photogonadosensitivity, with the photosensitive phase beginning 12.5 h after dawn. In this species, photoperiod length controls both the beginning and the end of the reproductive period. These results differ from those obtained with continental populations of wild rabbits, in which reproduction is inhibited by short day length. This difference may reflect genetic drift linked to the geographic isolation of this population, which is known to have been present on this small island for more than 2000 yr.     

The interactive effects of irradiance and photoperiod on Chara vulgaris L.: concerted responses in morphology, physiology, and reproduction

Both the single and interactive effects of irradiance and photoperiod on a worldwide charophyte species, Chara vulgaris L., were investigated in a greenhouse experiment. Under high light intensity, plants exhibited shortened shoot, compact canopy and low Chl a/Caro. In contrast, elongated shoot, expanded canopy and low Chl a/Chl b corresponded to low light intensity. In addition, both ash mass ratio and relative growth rate (RGR) were positively related to light intensity. The effect of photoperiod on plants was relatively complex. Although photoperiod did not affect morphological characters, an increased photoperiod significantly decreased Chl a/Chl b and Chl a/Caro ratios. Two-way analysis of variance (ANOVA) analysis indicated that significant interaction of irradiance and photoperiod was present on ash mass ratio, RGR, Chl a/Chl b, Chl a/Caro and Chl (a + b)/Caro ratios. The high RGR found for 50% sunlight, L:D 16:8 (50/16) conditions along with the significant interaction of irradiance and photoperiod on RGR indicated that the effect of irradiance was more important than photoperiod for plant growth. And finally, both irradiance and photoperiod had positive effects on the emergence of sex organs (♂♀) and the maturation of oospores, except that increased photoperiod did not accelerate the maturation of oospores. In summary, for both plant growth and reproduction, C. vulgaris was able to acclimate morphologically and physiologically to different irradiance levels and photoperiods. This study can partly explain the broad geographic distribution of C. vulgaris. Handling editor: S. M. Thomaz     

Impact of photoperiod manipulation on day/night changes in melatonin, sex steroids and vitellogenin plasma levels and spawning rhythms in Senegal sole, Solea senegalensis

Photoperiod and temperature are known as the main synchronizers of seasonal reproduction in fish. This paper studied the role of photoperiod on the synchronization of F1 Senegal sole reproduction rhythms. Fish were maintained under constant short-photoperiod (9L:15D) from the winter solstice onwards (experimental group) or under naturally-changing photoperiod (control group), and water temperature naturally oscillated in both groups. Blood samples were collected during the reproduction season at pre-spawning (March), spawning (April) and post-spawning (May) to determine the endocrine status. Spawning events and egg quality parameters were also monitored. The results revealed a significant increase in nocturnal melatonin concentration from March to May in the control group, while in the experimental group such seasonal change did not occur. As to plasma levels of vitellogenin, testosterone, estradiol and 11keto-testosterone, differences between groups were found mostly in March, while in April and May levels were often similar. Spawning was observed in both groups, although the experimental group started slightly earlier and also finished earlier than the control group, perhaps as a result of the increase in sex steroids and VTG observed at pre-spawning. Briefly, reproduction rhythms persisted in the absence of the natural lengthening of photoperiod, although photoperiod manipulation altered the seasonal modulation of melatonin, increased sex steroids and vitellogenin at pre-spawning, and slightly advanced the timing of spawning.     

Global climate change and invariable photoperiods: A mismatch that jeopardizes animal fitness

The Earth's surface temperature is rising, and precipitation patterns throughout the Earth are changing; the source of these shifts is likely anthropogenic in nature. Alterations in temperature and precipitation have obvious direct and indirect effects on both plants and animals. Notably, changes in temperature and precipitation alone can have both advantageous and detrimental consequences depending on the species. Typically, production of offspring is timed to coincide with optimal food availability; thus, individuals of many species display annual rhythms of reproductive function. Because it requires substantial time to establish or re‐establish reproductive function, individuals cannot depend on the arrival of seasonal food availability to begin breeding; thus, mechanisms have evolved in many plants and animals to monitor and respond to day length in order to anticipate seasonal changes in the environment. Over evolutionary time, there has been precise fine‐tuning of critical photoperiod and onset/offset of seasonal adaptations. Climate change has provoked changes in the availability of insects and plants which shifts the timing of optimal reproduction. However, adaptations to the stable photoperiod may be insufficiently plastic to allow a shift in the seasonal timing of bird and mammal breeding. Coupled with the effects of light pollution which prevents these species from determining day length, climate change presents extreme evolutionary pressure that can result in severe deleterious consequences for individual species reproduction and survival. This review describes the effects of climate change on plants and animals, defines photoperiod and the physiological events it regulates, and addresses the consequences of global climate change and a stable photoperiod.     

Photoperiod and temperature interaction in the determination of reproduction of the edible snail, Helix pomatia

Snails were kept in self-cleaning housing chambers in an artificially controlled environment. Mating was frequent under long days (18 h light) and rare under short days (8 h light) regardless of whether the snails were kept at 15 degrees C or 20 degrees C. An interaction between photoperiod and temperature was observed for egg laying. The number of eggs laid (45-50/snail) and the frequency of egg laying (90-130%) were greater in long than in short days (16-35/snail and 27-77%) but a temperature of 20 degrees C redressed, to some extent, the inhibitory effect of short days. At both temperatures only long photoperiods brought about cyclic reproduction over a period of 16 weeks, confirming the synchronizing role of photoperiod on the neuroendocrine control of egg laying in this species of snail.