A comprehensive analysis of protein-protein interactions in Saccharomyces cerevisiae

Two large-scale yeast two-hybrid screens were undertaken to identify protein-protein interactions between full-length open reading frames predicted from the Saccharomyces cerevisiae genome sequence. In one approach, we constructed a protein array of about 6,000 yeast transformants, with each transformant expressing one of the open reading frames as a fusion to an activation domain. This array was screened by a simple and automated procedure for 192 yeast proteins, with positive responses identified by their positions in the array. In a second approach, we pooled cells expressing one of about 6,000 activation domain fusions to generate a library. We used a high-throughput screening procedure to screen nearly all of the 6,000 predicted yeast proteins, expressed as Gal4 DNA-binding domain fusion proteins, against the library, and characterized positives by sequence analysis. These approaches resulted in the detection of 957 putative interactions involving 1,004 S. cerevisiae proteins. These data reveal interactions that place functionally unclassified proteins in a biological context, interactions between proteins involved in the same biological function, and interactions that link biological functions together into larger cellular processes. The results of these screens are shown here.     

Diversity, phenology, and elevational distribution of Ephemeroptera, Plecoptera, and Trichoptera in American Fork Canyon, Utah

Although the aquatic insect fauna of Utah and their associated adult forms are well documented taxonomically and biogeographically, little is known about seasonal and elevational patterns of aquatic insect diversity in individual Wasatch streams. We selected the American Fork River, a relatively pristine stream with little anthropogenic disturbance, as our target stream to investigate elevational distribution and seasonal phenology of adult forms of Ephemeroptera, Plecoptera, and Trichoptera (EPT). From April to October in 2003 through 2005, a total of 71 adult forms of EPT species were documented along the American Fork River. No single sampling period captured more than 30 species, and richness per sampling period averaged 8 species for all sites combined. The mid-elevational site (1862 msl) was the most species rich, with 54 species of transitional fauna captured along the elevational gradient. As such, this site is an important reference for maximum potential richness. Plecoptera emerged earlier in the year than Trichoptera, with the Plecoptera-dominated community being most rich in June, and the Trichoptera-dominated community being most rich in August. We observed 3 distinct seasonal species suites and 3 elevationally zoned community assemblages that were recurrent in their timing and location from year to year. The compiled species lists, life histories, and preliminary investigation of ecological trends provide a firm basis for further systematic studies on the ecology, water quality, and conservation of the aquatic insects of the American Fork River and similar mountain streams, particularly in the Wasatch region. Aunque la fauna de insectos acuáticos de Utah y sus formas adultas asociadas están bien documentadas taxonómica y biogeográficamente, se conoce poco sobre los patrones de distribución estacionales y altitudinales de la diversidad de insectos acuáticos en arroyos individuales de la cordillera Wasatch. Seleccionamos el Río American Fork, un arroyo relativamente prístino con poca perturbación antropogénica, como nuestro objetivo para investigar la distribución altitudinal de las formas adultas de Ephemeroptera, Plecoptera y Trichoptera (EPT), así como su fenología estacional. De abril a octubre del año 2003 al 2005, se documentó un total de 71 formas adultas de especies de EPT a lo largo del Río American Fork. No se encontraron más de 30 especies en ninguno de los períodos de muestreo, y combinando los datos de todos los sitios, el promedio de especies por período fue ocho. El sitio de elevación media (1862 msnm) fue el más rico con 54 especies constituidas por una fauna transicional entre los sitios a lo largo del gradiente de elevación, y como tal éste es un importante punto de referencia para determinar el máximo potencial de riqueza de especies. Los plecópteros aparecieron más temprano en el año que los tricópteros—la comunidad predominada por Plecoptera fue más rica en especies en junio—mientras que la comunidad predominantemente Trichoptera alcanzó su mayor riqueza en agosto. Observamos tres distintos conjuntos estacionales de especies y tres comunidades distribuidas por elevación, las cuales fueron recurrentes en su temporalidad y localización año tras año. La lista recopilada de especies, las historias de vida y la investigación preliminar de tendencias ecológicas aportan una firme base para más estudios sistemáticos y ecológicos, así como de calidad de agua y conservación de los insectos acuáticos del Río American Fork y otros arroyos semejantes a este, particularmente en la región de la cordillera Wasatch.     

Millennial-scale trends in west Pacific warm pool hydrology since the Last Glacial Maximum

Models and palaeoclimate data suggest that the tropical Pacific climate system plays a key part in the mechanisms underlying orbital-scale and abrupt climate change. Atmospheric convection over the western tropical Pacific is a major source of heat and moisture to extratropical regions, and may therefore influence the global climate response to a variety of forcing factors. The response of tropical Pacific convection to changes in global climate boundary conditions, abrupt climate changes and radiative forcing remains uncertain, however. Here we present three absolutely dated oxygen isotope records from stalagmites in northern Borneo that reflect changes in west Pacific warm pool hydrology over the past 27,000 years. Our results suggest that convection over the western tropical Pacific weakened 18,000-20,000 years ago, as tropical Pacific and Antarctic temperatures began to rise during the early stages of deglaciation. Convective activity, as inferred from oxygen isotopes, reached a minimum during Heinrich event 1 (ref. 10), when the Atlantic meridional overturning circulation was weak, pointing to feedbacks between the strength of the overturning circulation and tropical Pacific hydrology. There is no evidence of the Younger Dryas event in the stalagmite records, however, suggesting that different mechanisms operated during these two abrupt deglacial climate events. During the Holocene epoch, convective activity appears to track changes in spring and autumn insolation, highlighting the sensitivity of tropical Pacific convection to external radiative forcing. Together, these findings demonstrate that the tropical Pacific hydrological cycle is sensitive to high-latitude climate processes in both hemispheres, as well as to external radiative forcing, and that it may have a central role in abrupt climate change events.     

A global disorder of imprinting in the human female germ line

Imprinted genes are expressed differently depending on whether they are carried by a chromosome of maternal or paternal origin. Correct imprinting is established by germline-specific modifications; failure of this process underlies several inherited human syndromes. All these imprinting control defects are cis-acting, disrupting establishment or maintenance of allele-specific epigenetic modifications across one contiguous segment of the genome. In contrast, we report here an inherited global imprinting defect. This recessive maternal-effect mutation disrupts the specification of imprints at multiple, non-contiguous loci, with the result that genes normally carrying a maternal methylation imprint assume a paternal epigenetic pattern on the maternal allele. The resulting conception is phenotypically indistinguishable from an androgenetic complete hydatidiform mole, in which abnormal extra-embryonic tissue proliferates while development of the embryo is absent or nearly so. This disorder offers a genetic route to the identification of trans-acting oocyte factors that mediate maternal imprint establishment.     

高光谱数据组分信息的盲分解方法

将基于独立成分分析(independent component analysis,ICA)技术的盲分解方法(blind signal separation,BSS)应用于遥感混合像元的定量分解,解决了幅度不确定性问题,实现了从高光谱数据中同时得到定量的组分光谱信息和组分权重信息。通过数值模拟实验提出了光谱反演区间的选择方法,进一步完善了该算法,且讨论了算法的稳健性。以陕西省横山县为试验区,从HYPERION高光谱影像中反演了各像元的植被覆盖度,并利用SPOT5影像进行了精度验证,结果表明该方法具有较高的精度。     

The effects of a juvenile hormone analogue on the male reproductive organs of the red cotton bug,Dysdercus cingulatus (Heteroptera)

Summary The maleDysdercus cingulatus F., when treated with the JHa, methyl-3, 7, 11-trimethyl-7, 11-dichloro-2-dodecenoate, showed striking morphological deformities in the gonads, such as formation of additional apical growth on the testes, highly deformed, reduced vasa deferentia and accessory glands.Acknowledgments. We wish to thank Prof. P. Ramchender Rao, Head, Department of Zoology, Osmania University for facilities and encouragement. The financial assistance to P. Judson and B. Julius Divakar by the Council of Scientific and Industrial Research, New Delhi is gratefully acknowledged.