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.     

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.     

A genetic screen in Drosophila for metastatic behavior

A genetic screen was designed in Drosophila to interrogate its genome for mutations sufficient to cause noninvasive tumors of the eye disc to invade neighboring or distant tissues. We found that cooperation between oncogenic RasV12 expression and inactivation of any one of a number of genes affecting cell polarity leads to metastatic behavior, including basement membrane degradation, loss of E-cadherin expression, migration, invasion, and secondary tumor formation. Inactivation of these cell polarity genes cannot drive metastatic behavior alone or in combination with other tumor-initiating alterations. These findings suggest that the oncogenic background of tissues makes a distinct contribution toward metastatic development.     

Steroid control of longevity in Drosophila melanogaster

Ecdysone, the major steroid hormone of Drosophila melanogaster, is known for its role in development and reproduction. Flies that are heterozygous for mutations of the ecdysone receptor exhibit increases in life-span and resistance to various stresses, with no apparent deficit in fertility or activity. A mutant involved in the biosynthesis of ecdysone displays similar effects, which are suppressed by feeding ecdysone to the flies. These observations demonstrate the importance of the ecdysone hormonal pathway, a new player in regulating longevity.     

Potential genetic variability of wild pairs of Drosophila melanogaster

Eleven of 21 wild pairs of Drosophlila niielaniogaster tested gave rise to at least 1 fly with crossvein defects out of 1000 F(2) progeny. Considered in the light of additional information, the results support the idea that an individual lpossesses to a large degree the potential variability of the population of which he is a member.     

A genetic constitution frustrating the sexual drive in Drosophila paulistorum

Hybrids obtained in the laboratory between two subspecies of Drosophila paulistorum possess a genetic constitution which is discordant enough so that the hybrid females repel the courtship of all males, and will mate with none. The hybrid males will court and will be rejected by almost all females, including their own hybrid siblings.     

Single-channel and genetic analyses reveal two distinct A-type potassium channels in Drosophila

Whole-cell and single-channel voltage-clamp techniques were used to identify and characterize the channels underlying the fast transient potassium current (A current) in cultured myotubes and neurons of Drosophila. The myotube (A1) and neuronal (A2) channels are distinct, differing in conductance, voltage dependence, and gating kinetics. The myotube currents have a faster and more voltage-dependent macroscopic inactivation rate, a larger steady-state component, and a less negative steady-state inactivation curve than the neuronal currents. The myotube channels have a conductance of 12 to 16 picosiemens, whereas the neuronal channels have a conductance of 5 to 8 picosiemens. In addition, the myotube channel is affected by Shaker mutations, whereas the neuronal channel is not. Together, these data suggest that the two channels are separate molecular structures, the expression of which is controlled, at least in part, by different genes.     

Global genetic change tracks global climate warming in Drosophila subobscura

Comparisons of recent with historical samples of chromosome inversion frequencies provide opportunities to determine whether genetic change is tracking climate change in natural populations. We determined the magnitude and direction of shifts over time (24 years between samples on average) in chromosome inversion frequencies and in ambient temperature for populations of the fly Drosophila subobscura on three continents. In 22 of 26 populations, climates warmed over the intervals, and genotypes characteristic of low latitudes (warm climates) increased in frequency in 21 of those 22 populations. Thus, genetic change in this fly is tracking climate warming and is doing so globally.     

Regulation of SREBP processing and membrane lipid production by phospholipids in Drosophila

Animal cells exert exquisite control over the physical and chemical properties of their membranes, but the mechanisms are obscure. We show that phosphatidylethanolamine, the major phospholipid in Drosophila, controls the release of sterol regulatory element-binding protein (SREBP) from Drosophila cell membranes, exerting feedback control on the synthesis of fatty acids and phospholipids. The finding that SREBP processing is controlled by different lipids in mammals and flies (sterols and phosphatidylethanolamine, respectively) suggests that an essential function of SREBP is to monitor cell membrane composition and to adjust lipid synthesis accordingly.     

接受美学与思想政治教育的接受性分析

通过借鉴接受美学对读者的接受研究成果,提出了思想政治教育的接受性内涵,并分析了思想政治教育自身的可接受性,具体从接受美学中的＂读者参与＂、＂审美经验＂和＂期待视野＂、＂第二文本＂3个方面进行借鉴,以提高思想政治教育的接受效果。     

A synthetic maternal-effect selfish genetic element drives population replacement in Drosophila

One proposed strategy for controlling the transmission of insect-borne pathogens uses a drive mechanism to ensure the rapid spread of transgenes conferring disease refractoriness throughout wild populations. Here, we report the creation of maternal-effect selfish genetic elements in Drosophila that drive population replacement and are resistant to recombination-mediated dissociation of drive and disease refractoriness functions. These selfish elements use microRNA-mediated silencing of a maternally expressed gene essential for embryogenesis, which is coupled with early zygotic expression of a rescuing transgene.     

Pheromone transport and reception in an amphipod

Sexual dimorphism in the second antennae of the amphipod Gammarus duebeni Lilljeborg is connected with the reception in the male of a female sex pheromone transported through the water. Investigations on tritium-labeled specimens were carried out with scintillator and autoradiographic techniques.     

波尔山羊部分生产性状的遗传分析

用 16 8头波尔种羊及其 345头后裔资料计算波尔山羊初生重、 1月龄和 2月龄体重的主效基因指数 ,并对其中 12头公羊的 2 5 6头后裔的窝产羔数、羔羊初生重、 1月龄和 2月龄体重进行遗传分析。结果窝产羔数、羔羊初生重、 1月龄和 2月龄体重的遗传力分别为 0 15 ,0 4 3,0 39和 0 35。产羔数与羔羊初生重、 1月龄和 2月龄体重间的表型相关系数分别为 0 32 ,0 4 5和 0 4 6 ;遗传相关系数分别为 - 0 34,- 0 36和 - 0 4 1。羔羊初生重与 1月龄和 2月龄体重间的表型相关系数分别为 0 5 9和 0 6 2 ;遗传相关系数分别为 0 6 4和 0 72。 1月龄和 2月龄体重间的表型相关系数和遗传相关系数分别为 0 6 8和 0 78。主效基因指数分析表明 ,初生重不存在主效基因遗传 ,而 1月龄和 2月龄体重存在主效基因遗传     

中华鳖与福寿螺的种间关系

本文阐述中华鳖营养价值高,被人们视为滋补佳品。野生中华鳖更是上品。福寿螺,一种外来入侵有害生物,需要控制和消灭。由于中华鳖与福寿螺之间特殊的种间关系,从而达到鳖肥螺控的效果。     

鹅掌楸属种间杂种苗期生长性状的遗传变异与优良遗传型选择

以1个中国马褂木（Liriodendron chinense (Hemsl.) Sarg.）自由授粉家系为对照,对鹅掌楸属23个种间杂种家系2 a生苗木生长性状的研究结果表明,在苗高和地径性状上,正交、反交、回交及F1个体之间相互杂交4种交配系统之间无显著差异,但家系间在两个性状上的差异均达极显著程度(P<0.01)。对于苗高性状,家系平均变异系数为29.16、家系内平均变幅为2.31 m,在地径性状上,家系平均变异系数为31.87、家系内平均变幅为2.63 cm。因此,在鹅掌楸属种间杂种优势开发中,上述     

Inducing sleep by remote control facilitates memory consolidation in Drosophila

Sleep is believed to play an important role in memory consolidation. We induced sleep on demand by expressing the temperature-gated nonspecific cation channel Transient receptor potential cation channel (UAS-TrpA1) in neurons, including those with projections to the dorsal fan-shaped body (FB). When the temperature was raised to 31°C, flies entered a quiescent state that meets the criteria for identifying sleep. When sleep was induced for 4 hours after a massed-training protocol for courtship conditioning that is not capable of inducing long-term memory (LTM) by itself, flies develop an LTM. Activating the dorsal FB in the absence of sleep did not result in the formation of LTM after massed training.     

Hormonal and genetic control of behavioral integration in honey bee colonies

The ability of insect colonies to adjust the division of labor among workers in response to changing environmental and colony conditions, coupled with research showing genetic effects on the division of labor in honey bee colonies, led to an investigation of the role of genetics and the environment in the integration of worker behavior. Measurements of juvenile hormone(JH) titers and allozyme analyses of worker honey bees suggest that two processes are involved in colony-level regulation of division of labor: (i) plasticity in age-dependent behavior is a consequence of modulation of JH titers by extrinsic factors, and (ii) stimuli that can affect JH titers and age-dependent behavior do elicit variable responses among genetically distinct subpopulations of workers within a colony. These results provide a new perspective on the developmental plasticity of insect colonies and support the emerging view that colony genetic structure affects behavioral organization.     

螺旋焊管生产中的质量控制

科威特金属钢厂(简称KMPI)生产的螺旋焊管的质量控制严格按照其质量控制程序和质量计划进行,以588×8.48 mm螺旋焊管为例,介绍了其生产过程中钢卷的质量控制、管子的成型及外焊缝的质量控制、超声波探伤、管子切割及力学性能试验质量控制、首次外观检查质量控制、缺陷检查及修补要求、射线检查质量控制、水压试验、最终检查和标记一整套质量控制程序。     

石油储罐预制生产中的质量控制

为了了解国外石油储罐在预制生产中质量控制的常规做法,介绍了中国石油工程建设公司在科威特集油站工程项目大罐预制生产中的质量控制程序、计划所使用的国际标准及控制过程,对今后承包国外大罐工程做好质量控制有一定的参考价值。     

烟草病害控制技术初探

在简述当前烟草病害控制措施的基础上,认为应该加强合理施肥方面的研究,以增强植株本身抗性,从而达到烟草优质、适产、低成本、低残留的生产目标。