Molecular transfer of a species-specific behavior from Drosophila simulans to Drosophila melanogaster

Drosophila males modulate the interpulse intervals produced during their courtship songs. These song cycles, which are altered by mutations in the clock gene period, exhibit a species-specific variation that facilitates mating. We have used chimeric period gene constructs from Drosophila melanogaster and Drosophila simulans in germline transformation experiments to map the genetic control of their song rhythm difference to a small segment of the amino acid encoding information within this gene.     

Hawaiian courtship songs: evolutionary innovation in communication signals of Drosophila

In Hawaii, flies of the genus Drosophila have undergone spectacular adaptive radiation, resulting in the evolution of more than 500 species of Drosophila that are found nowhere else on earth. This taxonomic uniqueness is reflected in behavior and morphology. Hawaiian Drosophila sing songs, as do continental Drosophila; however, the Hawaiian songs have diverged strongly in form and mechanism of production. The click-song of D. fasciculisetae's (Maui) has a carrier frequency an order of magnitude higher than those reported in familiar continental species, such as D. melanogaster (170 hertz). Drosophila fasciculisetae's song resembles a cicada's more than a fly's song. The song of D. cyrtoloma (Maui) has a complex pulse rhythm more typical of crickets than flies. The pulse song of D. silvestris (Hawaii) closely resembles that of D. melanogaster in both pulse rhythm and carrier frequency, but D. melanogaster sings by vibrating its wings, whereas D. silvestris sings through abdominal vibrations. These mechanisms are radical departures from the continental wing song mechanism and are further examples of the remarkable behavioral innovation that has occurred in the Drosophila of Hawaii during their evolutionary transit through these islands.     

Songs of humpback whales

1) Humpback whales (Megaptera novaeangliae) produce a series of beautiful and varied sounds for a period of 7 to 30 minutes and then repeat the same series with considerable precision. We call such a performance "singing" and each repeated series of sounds a "song." 2) All prolonged sound patterns (recorded so far) of this species are in song form, and each individual adheres to its own song type. 3) There seem to be several song types around which whales construct their songs, but individual variations are pronounced (there is only a very rough species-specific song pattern). 4) Songs are repeated without any obvious pause between them; thus song sessions may continue for several hours. 5) The sequence of themes in successive songs by the same individual is the same. Although the number of phrases per theme varies, no theme is ever completely omitted in our sample. 6) Loud sounds in the ocean, for example dynamite blasts, do not seem to affect the whale's songs. 7) The sex of the performer of any of the songs we have studied is unknown. 8) The function of the songs is unknown.     

Song replay during sleep and computational rules for sensorimotor vocal learning

Songbirds learn a correspondence between vocal-motor output and auditory feedback during development. For neurons in a motor cortex analog of adult zebra finches, we show that the timing and structure of activity elicited by the playback of song during sleep matches activity during daytime singing. The motor activity leads syllables, and the matching sensory response depends on a sequence of typically up to three of the preceding syllables. Thus, sensorimotor correspondence is reflected in temporally precise activity patterns of single neurons that use long sensory memories to predict syllable sequences. Additionally, "spontaneous" activity of these neurons during sleep matches their sensorimotor activity, a form of song "replay." These data suggest a model whereby sensorimotor correspondences are stored during singing but do not modify behavior, and off-line comparison (e.g., during sleep) of rehearsed motor output and predicted sensory feedback is used to adaptively shape motor output.     

Simulation of the mating advantage in mating of rare drosophila males

In several species of Drosophila, certain males mate more frequently when they are less abundant than they do when they are in the majority. The mating advantage may be artificially induced by the use of a "double chamber" technique, even when there is no difference in the actual frequencies of the competing males.     

A test for responsiveness to song structure and programming in female sparrows

Female song sparrows, primed with implants of estradiol, gave the solicitation display for copulation in response to acoustic stimulation with song. This technique demonstrated that female song sparrows respond more strongly to conspecific song than to alien songs, that they discriminate on the basis of both overall temporal pattern and syllabic structure, that they respond more to several song types than to repetitions of one song, and that they are most responsive to several song types if the songs are organized in bouts of a single type, as they are normally delivered by a male song sparrow. These results demonstrate a substantial correspondence between the structure and programming of the singing behavior of male birds and female responsiveness to song.     

Genetic control of song specificity in crickets

The calling song of male field crickets is composed of stereotyped rhythmic pulse intervals, which are predictable expressions of genotype. Females identify conspecific males by their song. Two species of crickets were found to exhibit species-specific song preference, and hybrids between them preferred hybrid calls over either parental call. These results imply genetic control of song reception as well as transmission.     

Sexual difference in pattern of hormone accumulation in the brain of a songbird

After adult zebra finches (Poephila guttata) received injections of tritiated testosterone, fewer hormone-concentrating cells were found in females than in males in two brain regions involved in song: hyperstriatum ventrale pars caudale and magnocellular nucleus of the anterior neostriatum. In some other regions, no sexual difference was detected. It is, therefore, possible that sex differences in the sensitivity of specific neural populations to hormones underlie the striking anatomical dimorphism observed in neural regions controlling song.     

气候变化对黄河首曲生态退化的影响

玛曲湿地被称为黄河的"蓄水池"和"高原水塔"。然而近30年来,由于气候变化和人类的过渡利用等原因造成了玛曲湿地的黄河"蓄水池"功能萎缩,,对当地生态环境和居民的生产和生存造成了严重的威胁。     

Completion of meiosis in uninseminated eggs of Drosophila melanogaster

Contrary to earlier statements, meiosis goes to completion in "Linfertilized" eggs of Drosophila melanogaster. Evidence suggests that this is not only characteristic of the strain examined but of the species as a whole and of other Drosophila species as well.     

北冬虫夏草提取液对果蝇繁殖力及寿命的影响

采用不同浓度的北冬虫夏草(简称北虫草)提取液(0.625%,1.250%,5.000%)分别处理野生黑腹果蝇,研究北虫草提取液对果蝇繁殖力及寿命的影响。结果表明:5.000%浓度组F1果蝇数与对照组比较有极显著差异(p<0.01),当北虫草提取液浓度低于1.250%时,果蝇的繁殖力有增加趋势;北虫草提取液对果蝇平均寿命无显著延长作用,但可显著提高第一子代果蝇营养物质的积累,促进其生长发育。     

Altered perception of species-specific song by female birds after lesions of a forebrain nucleus

Female birds that do not normally sing possess brain nuclei associated with song production in males. To determine whether one song nucleus, the caudal nucleus of the ventral hyperstriatum (HVc), acts in conspecific song perception, courtship responses of female canaries to canary and white-crowned sparrow songs were compared before and after HVc lesions. Bilateral lesions of a portion of the HVc resulted in copulation solicitations to heterospecific song as well as conspecific song. Control females continued to respond only to conspecific song. This suggests that the HVc is critical for conspecific song perception in females. Because female canaries do not normally sing, neurons in female HVc must develop response selectivity by a mechanism different from that proposed for male birds in the motor theory of song perception.     

昆虫纲与线虫纲miRNAs碱基组成特征分析

[目的]为全面认识miRNA的结构属性和miRNA基因识别策略的设计提供帮助。[方法]利用miRNA数据库,借助于相关的生物信息学软件和数据统计软件,对昆虫纲与线虫纲部分物种(黑腹果蝇、暗果蝇、西方蜜蜂、冈比亚疟蚊、秀丽线杆线虫、线虫种)的已知miRNA序列的碱基组成进行统计分析。[结果]6种生物的miRNA序列中,腺嘌呤(A)含量较为稳定,在碱基组成上AU含量高于GC含量。比较同一物种pre-miRNA与mat-miRNA间相同碱基含量发现,除黑腹果蝇pre-miRNA与mat-miRNA在胞嘧啶(C)的含量上存在显著差异外,其余均未见显著差异。[结论]推测miRNA碱基组成上AU含量高可能与其调控基因表达功能和物种的进化关系有关。     

基于MIDI技术的歌声自动伴奏

提出了歌声自动伴奏的方法,介绍了歌声向乐器转化的方法和MIDI技术,阐述了歌声乐器的自动伴奏原理,给出了基于MIDI技术的歌声自动伴奏方法。     

Deuterium oxide effect on temperature-dependent survival in populations of Drosophila melanogaster

A comparison of the mean life-spans for populations of Drosophila melanogaster at 10 degrees , 20 degrees , 25 degrees , and 30 degrees C maintained on media prepared with distilled water and with 50 percent deuterium oxide shows that deuteration decreases longevity at all four temperatures. The magnitude of the difference between the mean survival times of populations maintained on deuterated and nondeuterated media is inversely related to temperature between 10 degrees and 30 degrees C.     

Genetic control of an insect neuronal network

Motor activity responsible for the calling song of crickets is generated by a small neuronal network whose output is genetically determined. Genes controlling certain output features are located on the X chromosome. The genetic system involved is polygenic and multichromosomal. In some patterns, genetically derived information is adequate to specify the difference of a single impulse in the output of homologous neurons from different genotypes.     

《伟大的盖茨比》中的象征意义

《了不起的盖茨比》是美国作家菲茨杰拉德一部具有浓烈悲剧色彩的小說,它紧扣时代脉搏,深刻揭露了当时社会道德的沦丧,集中暴露了20世纪20年代美国梦的破灭,对美国现代社会的讽刺可谓入木三分。     

Temporal pattern as a cue for species-specific calling song recognition in crickets

Female crickets can recognize conspecific calling song from its temporal pattern alone. In Teleogryllus oceanicus, the song pattern consists of three classes of interpulse intervals arranged in a stereotyped sequence. Females recognize a model song in which the sequential order of intervals is random. This argues against the hypothesis that recognition results from matching auditory input to an internal template of the song.     

歌曲翻译之选择——兼论翻唱歌曲的流行对歌曲翻译的冲击

歌曲是文字和音乐相结合的综合艺术,其翻译不同于其他文体的翻译。当前翻唱歌曲的流行表明,传统翻译观的"信"或"忠实"已经受到挑战,歌曲的传播性和商业化会影响到译者的翻译选择。文章就歌词大意和具备可唱性的歌词译配两种主要类型及其优劣势进行了详细讨论,并结合南非世界杯宣传歌曲Wavin Flag的中文版《旗开得胜》,探讨了歌曲翻唱现象,指出针对依靠媒介载体传播、面向市场的歌曲文本不仅要考虑"忠实"的翻译观,还需满足歌曲翻译在特定场合的不同需求。     

引导学生有效分析遗传学综合性实验结果的探索与实践

以6#和2#果蝇的杂交为例,探讨了学生在实验过程中常出现的问题以及如何加强引导学生对实验结果的分析。认为分析"果蝇的综合杂交实验"的数据应从1对遗传因子分析到2对遗传因子分析,再到3对遗传因子分析;分析内容应包括性状的显隐判断、基因位置的确定、表现型比例和假设检验。同时,在实验的各个环节引导学生复习、巩固遗传学的基本原理。在实验的设计阶段让学生思考影响实验结果的因素。实践表明,学生对实验结果的分析不仅思路清晰、逻辑性增强,而且充分挖掘了实验数据所蕴含的信息,从而提高了遗传学实验教学质量。