Functional links between Aβ toxicity, endocytic trafficking, and Alzheimer's disease risk factors in yeast     

Treusch S  Hamamichi S  Goodman JL  Matlack KE  Chung CY  Baru V  Shulman JM  Parrado A  Bevis BJ  Valastyan JS  Han H  Lindhagen-Persson M  Reiman EM  Evans DA  Bennett DA  Olofsson A  DeJager PL  Tanzi RE  Caldwell KA  Caldwell GA  Lindquist S 《Science (New York, N.Y.)》2011,334(6060):1241-1245

Aβ (beta-amyloid peptide) is an important contributor to Alzheimer's disease (AD). We modeled Aβ toxicity in yeast by directing the peptide to the secretory pathway. A genome-wide screen for toxicity modifiers identified the yeast homolog of phosphatidylinositol binding clathrin assembly protein (PICALM) and other endocytic factors connected to AD whose relationship to Aβ was previously unknown. The factors identified in yeast modified Aβ toxicity in glutamatergic neurons of Caenorhabditis elegans and in primary rat cortical neurons. In yeast, Aβ impaired the endocytic trafficking of a plasma membrane receptor, which was ameliorated by endocytic pathway factors identified in the yeast screen. Thus, links between Aβ, endocytosis, and human AD risk factors can be ascertained with yeast as a model system.  相似文献   

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

Chen CH  Huang H  Ward CM  Su JT  Schaeffer LV  Guo M  Hay BA 《Science (New York, N.Y.)》2007,316(5824):597-600

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.  相似文献   

A hexagonal (wurtzite) form of silicon     

Jennings HM  Richman MH 《Science (New York, N.Y.)》1976,193(4259):1242-1243

The existence of a hexagonal (wurtzite) form of silicon, similar to that form of diamond (carbon) observed in meteorites and in the laboratory, has been identified by x-ray diffraction in reaction-bonded silicon nitride containing unreacted silicon. The presence of this phase is due to stresses created in the silicon by the nitridation reaction.  相似文献   

Polar lightning and decadal-scale cloud variability on Jupiter     

Baines KH  Simon-Miller AA  Orton GS  Weaver HA  Lunsford A  Momary TW  Spencer J  Cheng AF  Reuter DC  Jennings DE  Gladstone GR  Moore J  Stern SA  Young LA  Throop H  Yanamandra-Fisher P  Fisher BM  Hora J  Ressler ME 《Science (New York, N.Y.)》2007,318(5848):226-229

Although lightning has been seen on other planets, including Jupiter, polar lightning has been known only on Earth. Optical observations from the New Horizons spacecraft have identified lightning at high latitudes above Jupiter up to 80 degrees N and 74 degrees S. Lightning rates and optical powers were similar at each pole, and the mean optical flux is comparable to that at nonpolar latitudes, which is consistent with the notion that internal heat is the main driver of convection. Both near-infrared and ground-based 5-micrometer thermal imagery reveal that cloud cover has thinned substantially since the 2000 Cassini flyby, particularly in the turbulent wake of the Great Red Spot and in the southern half of the equatorial region, demonstrating that vertical dynamical processes are time-varying on seasonal scales at mid- and low latitudes on Jupiter.  相似文献   

Comparative influence of isolation,landscape, and wetland characteristics on egg-mass abundance of two pool-breeding amphibian species     

Jessica?S.?VeyseyEmail author  Sandra?D.?Mattfeldt  Kimberly?J.?Babbitt 《Landscape Ecology》2011,26(5):661-672

The distribution and abundance of species are shaped by local and landscape processes, but the dominant processes may differ with scale and increasing human disturbance. We investigated population responses of two pool-breeding amphibian species to differences in local and landscape characteristics in suburbanizing, southeastern New Hampshire, USA. In 2003 and 2004, we sampled 49 vernal pools for spotted salamander (Ambystoma maculatum) and wood frog (Lithobates sylvaticus) egg masses. Using egg masses as a proxy for breeding-female population size, we examined the relative influence of five land-use and three isolation variables at two scales (300 and 1000 m) and five wetland variables on egg-mass abundance. For both species, road density at the landscape scale (1000 m) and hydroperiod most strongly predicted egg-mass abundance, with abundance decreasing as roads became denser and hydroperiods shortened. Wetland isolation was also an important predictor, with abundance greatest at more isolated pools, suggesting that both species concentrate at isolated pools when alternative breeding sites are scarce. Surprisingly, no 300-m parameters were strongly associated with salamander egg-mass abundance, whereas several landscape parameters were. In suburbanizing areas, it is at least as important to consider landscape-scale road density as to consider hydroperiod when designing conservation plans for these species. Furthermore, both isolated and clustered pools provide these species important habitat and may require protection. Finally, the conceptual framework for spotted-salamander management must be expanded so that spatial configuration at the landscape scale becomes a regular, integrated component of conservation planning for this species.  相似文献   

A review of the conservation threats to carnivorous plants     

David E. Jennings  Jason R. Rohr 《Biological conservation》2011,(5):1356-1363

Over half of the carnivorous plant species assessed by the International Union for the Conservation of Nature (IUCN) are listed as threatened (i.e. vulnerable, endangered, or critically endangered), but the threats to carnivorous plants have not previously been quantified systematically. In this review, we quantify the conservation threats to carnivorous plant taxa worldwide. Using the IUCN Red List, a literature search of Web of Knowledge, and the National Red Lists database, we collected data on the threats to 48 species of carnivorous plants from nine genera. The most common threat was habitat loss from agriculture, followed by the collection of wild plants, pollution, and natural systems modifications. A principal coordinate analysis revealed that species within a genus often faced similar threats, and an indicator species analysis found positive associations among species in the genus Sarracenia and agricultural activities, over-collection, invasive species, and pollution. Future research should further quantify the effects of pollution on carnivorous plants, and more thoroughly examine the potential role of carnivorous plants as indicator species for wetland health. More research is also needed to quantify the extinction risk for many carnivorous plants, as presently only around 17% of species have been assessed by the IUCN. Ensuring the conservation of carnivorous plants will help maintain the important ecosystem services they provide and prevent secondary extinctions of specialist species that rely on them.  相似文献   

Rice bran fermented with saccharomyces boulardii generates novel metabolite profiles with bioactivity     

Ryan EP  Heuberger AL  Weir TL  Barnett B  Broeckling CD  Prenni JE 《Journal of agricultural and food chemistry》2011,59(5):1862-1870

Emerging evidence supporting chronic disease fighting properties of rice bran has advanced the development of stabilized rice bran for human use as a functional food and dietary supplement. A global and targeted metabolomic investigation of stabilized rice bran fermented with Saccharomyces boulardii was performed in three rice varieties. Metabolites from S. boulardii-fermented rice bran were detected by gas chromatography-mass spectrometry (GC-MS) and assessed for bioactivity compared to nonfermented rice bran in normal and malignant lymphocytes. Global metabolite profiling revealed significant differences in the metabolome that led to discovery of candidate compounds modulated by S. boulardii fermentation. Fermented rice bran extracts from three rice varieties reduced growth of human B lymphomas compared to each variety's nonfermented control and revealed that fermentation differentially altered bioactive compounds. These data support that integration of global and targeted metabolite analysis can be utilized for assessing health properties of rice bran phytochemicals that are enhanced by yeast fermentation and that differ across rice varieties.  相似文献   

Evaluation of intrarenal mesenchymal stem cell injection for treatment of chronic kidney disease in cats: a pilot study     

Quimby JM  Webb TL  Gibbons DS  Dow SW 《Journal of Feline Medicine and Surgery》2011,13(6):418-426

The feasibility of autologous intrarenal mesenchymal stem cell (MSC) therapy in cats with chronic kidney disease (CKD) was investigated. Six cats (two healthy, four with CKD) received a single unilateral intrarenal injection of autologous bone marrow-derived or adipose tissue-derived MSC (bmMSC or aMSC) via ultrasound guidance. Minimum database and glomerular filtration rate (GFR) via nuclear scintigraphy were determined pre-injection, at 7 days and at 30 days post-injection. Intrarenal injection did not induce immediate or long-term adverse effects. Two cats with CKD that received aMSC experienced modest improvement in GFR and a mild decrease in serum creatinine concentration. Despite the possible benefits of intrarenal MSC injections for CKD cats, the number of sedations and interventions required to implement this approach would likely preclude widespread clinical application. We concluded that MSC could be transferred safely by ultrasound-guided intrarenal injection in cats, but that alternative sources and routes of MSC therapy should be investigated.  相似文献   

A comparison of analytical methods for chlorodibenzo-p-dioxins in pentachlorophenol.     

E C Villanueva  R W Jennings  V W Burse  R D Kimbrough 《Journal of agricultural and food chemistry》1975,23(6):1089-1091

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Effect of inoculation with wild type Azospirillum brasilense and A. irakense strains on development and nitrogen uptake of spring wheat and grain maize     

Sofie Dobbelaere  Anja Croonenborghs  Amber Thys  David Ptacek  Yaacov Okon  Jos Vanderleyden 《Biology and Fertility of Soils》2002,36(4):284-297

Under the controlled conditions of the greenhouse and by varying some biotic and abiotic factors, we tried to identify some of the factors critical to obtain successful Azospirillum inoculation. Spring wheat and grain maize were inoculated with different concentrations of the wild type strains A. brasilense Sp245 and A. irakense KBC1, and grown in a substrate with varying concentrations of organic matter (OM) and N fertiliser. The inoculum concentration was one of the factors that influenced most the outcome of an inoculation experiment on wheat, with lower inoculum concentrations (10⁵-10⁶ cfu plant^-1) stimulating root development and plant dry weight and higher inoculum concentrations (10⁷-10⁸ cfu plant^-1) having no effect or sometimes even inhibiting root development. The effect of inoculation was most pronounced at low to intermediate N fertilisation levels, while the OM content of the substrate had no effect. Inoculation was found to affect early plant and root development, plant and root dry weight, grain yield and the N-uptake efficiency of plants. However, inoculation did not change the N concentration in plants or grains. In addition, a difference in the ability of both strains to stimulate plant growth and N uptake of wheat and maize was observed, with A. brasilense Sp245 having most effect on spring wheat and A. irakense KBC1 being more effective on grain maize. The significance of the obtained results for agriculture is discussed.  相似文献