Wheat Leaf Rust: Control by 4-n-Butyl-1,2,4-triazole, a Systemic Fungicide     

von Meyer WC  Greenfield SA  Seidel MC 《Science (New York, N.Y.)》1970,169(3949):997-998

Compound 4-n-butyl-1,2,4-triazole was demonstrated as an enduring and selective systemic fungicide for the control of wheat leaf rust by foliar and soil applications. Among several species of rust fungi treated, only wheat leaf rust (Puccinia recondita Rob.) was controlled. Wheat stem rust, for example, was unaffected by either soil or foliar applications.  相似文献   

Spreading of the ocean floor: undeformed sediments in the peru-chile trench     

Scholl DW  von Huene R  Ridlon JB 《Science (New York, N.Y.)》1968,159(3817):869-871

None of the expected stratigraphic and structural effects of a spreading sea floor have been imposed on the sedimentary fill of the Peru-Chile Trench. During at least the last several million years, and perhaps during much of the Cenozoic, the trench has not been affected by an oceanic crust thrusting under the continent.  相似文献   

Dynamic visualization of thrombopoiesis within bone marrow     

Junt T  Schulze H  Chen Z  Massberg S  Goerge T  Krueger A  Wagner DD  Graf T  Italiano JE  Shivdasani RA  von Andrian UH 《Science (New York, N.Y.)》2007,317(5845):1767-1770

Platelets are generated from megakaryocytes (MKs) in mammalian bone marrow (BM) by mechanisms that remain poorly understood. Here we describe the use of multiphoton intravital microscopy in intact BM to visualize platelet generation in mice. MKs were observed as sessile cells that extended dynamic proplatelet-like protrusions into microvessels. These intravascular extensions appeared to be sheared from their transendothelial stems by flowing blood, resulting in the appearance of proplatelets in peripheral blood. In vitro, proplatelet production from differentiating MKs was enhanced by fluid shear. These results confirm the concept of proplatelet formation in vivo and are consistent with the possibility that blood flow-induced hydrodynamic shear stress is a biophysical determinant of thrombopoiesis.  相似文献   

Self-nonself discrimination by T cells   总被引：28，自引：0，他引：28  

H von Boehmer  P Kisielow 《Science (New York, N.Y.)》1990,248(4961):1369-1373

The alpha beta T cell receptor (TCR) recognizes antigens that are presented by major histocompatibility complex (MHC)-encoded cell surface molecules by binding to both the antigen and the MHC molecules. Discrimination of self from nonself antigens and MHC molecules is achieved by negative and positive selection of T cells in the thymus: potentially harmful T cells with receptors that bind to self antigens plus self MHC molecules are deleted before they can mount immune responses. In contrast, the maturation of useful T cells with receptors that bind foreign antigens plus self MHC molecules requires the binding of their receptor to MHC molecules on thymic epithelium in the absence of foreign antigen. The binding of the TCR to either class I or class II MHC molecules directs differentiation of the selected cells into either CD4-8+ (killer) or CD4+8- (helper) T cells, respectively.  相似文献   

Prevention of organ allograft rejection by a specific Janus kinase 3 inhibitor     

Changelian PS  Flanagan ME  Ball DJ  Kent CR  Magnuson KS  Martin WH  Rizzuti BJ  Sawyer PS  Perry BD  Brissette WH  McCurdy SP  Kudlacz EM  Conklyn MJ  Elliott EA  Koslov ER  Fisher MB  Strelevitz TJ  Yoon K  Whipple DA  Sun J  Munchhof MJ  Doty JL  Casavant JM  Blumenkopf TA  Hines M  Brown MF  Lillie BM  Subramanyam C  Shang-Poa C  Milici AJ  Beckius GE  Moyer JD  Su C  Woodworth TG  Gaweco AS  Beals CR  Littman BH  Fisher DA  Smith JF  Zagouras P  Magna HA  Saltarelli MJ  Johnson KS  Nelms LF  Des Etages SG  Hayes LS  Kawabata TT 《Science (New York, N.Y.)》2003,302(5646):875-878

Because of its requirement for signaling by multiple cytokines, Janus kinase 3 (JAK3) is an excellent target for clinical immunosuppression. We report the development of a specific, orally active inhibitor of JAK3, CP-690,550, that significantly prolonged survival in a murine model of heart transplantation and in cynomolgus monkeys receiving kidney transplants. CP-690,550 treatment was not associated with hypertension, hyperlipidemia, or lymphoproliferative disease. On the basis of these preclinical results, we believe JAK3 blockade by CP-690,550 has potential for therapeutically desirable immunosuppression in human organ transplantation and in other clinical settings.  相似文献   

A gain-of-function mutation in a cytokinin receptor triggers spontaneous root nodule organogenesis     

Tirichine L  Sandal N  Madsen LH  Radutoiu S  Albrektsen AS  Sato S  Asamizu E  Tabata S  Stougaard J 《Science (New York, N.Y.)》2007,315(5808):104-107

Legume root nodules originate from differentiated cortical cells that reenter the cell cycle and form organ primordia. We show that perception of the phytohormone cytokinin is a key element in this switch. Mutation of a Lotus japonicus cytokinin receptor gene leads to spontaneous development of root nodules in the absence of rhizobia or rhizobial signal molecules. The mutant histidine kinase receptor has cytokinin-independent activity and activates an Escherichia coli two-component phosphorelay system in vivo. Mutant analysis shows that cytokinin signaling is required for cell divisions that initiate nodule development and defines an autoregulated process where cytokinin induction of nodule stem cells is controlled by shoots.  相似文献   

Materials science. A picosecond view of melting     

von der Linde D 《Science (New York, N.Y.)》2003,302(5649):1345-1346

  相似文献   

Geophysics. When seamounts subduct     

von Huene R 《Science (New York, N.Y.)》2008,321(5893):1165-1166

  相似文献   

Cross-linking cellular prion protein triggers neuronal apoptosis in vivo     

Solforosi L  Criado JR  McGavern DB  Wirz S  Sánchez-Alavez M  Sugama S  DeGiorgio LA  Volpe BT  Wiseman E  Abalos G  Masliah E  Gilden D  Oldstone MB  Conti B  Williamson RA 《Science (New York, N.Y.)》2004,303(5663):1514-1516

Neuronal death is a prominent, but poorly understood, pathological hallmark of prion disease. Notably, in the absence of the cellular prion protein (PrPC), the disease-associated isoform, PrPSc, appears not to be intrinsically neurotoxic, suggesting that PrPC itself may participate directly in the prion neurodegenerative cascade. Here, cross-linking PrPC in vivo with specific monoclonal antibodies was found to trigger rapid and extensive apoptosis in hippocampal and cerebellar neurons. These findings suggest that PrPC functions in the control of neuronal survival and provides a model to explore whether cross-linking of PrPC by oligomeric PrPSc can promote neuronal loss during prion infection.  相似文献   

Comparative genome and proteome analysis of Anopheles gambiae and Drosophila melanogaster     

Zdobnov EM  von Mering C  Letunic I  Torrents D  Suyama M  Copley RR  Christophides GK  Thomasova D  Holt RA  Subramanian GM  Mueller HM  Dimopoulos G  Law JH  Wells MA  Birney E  Charlab R  Halpern AL  Kokoza E  Kraft CL  Lai Z  Lewis S  Louis C  Barillas-Mury C  Nusskern D  Rubin GM  Salzberg SL  Sutton GG  Topalis P  Wides R  Wincker P  Yandell M  Collins FH  Ribeiro J  Gelbart WM  Kafatos FC  Bork P 《Science (New York, N.Y.)》2002,298(5591):149-159

Comparison of the genomes and proteomes of the two diptera Anopheles gambiae and Drosophila melanogaster, which diverged about 250 million years ago, reveals considerable similarities. However, numerous differences are also observed; some of these must reflect the selection and subsequent adaptation associated with different ecologies and life strategies. Almost half of the genes in both genomes are interpreted as orthologs and show an average sequence identity of about 56%, which is slightly lower than that observed between the orthologs of the pufferfish and human (diverged about 450 million years ago). This indicates that these two insects diverged considerably faster than vertebrates. Aligned sequences reveal that orthologous genes have retained only half of their intron/exon structure, indicating that intron gains or losses have occurred at a rate of about one per gene per 125 million years. Chromosomal arms exhibit significant remnants of homology between the two species, although only 34% of the genes colocalize in small "microsyntenic" clusters, and major interarm transfers as well as intra-arm shuffling of gene order are detected.  相似文献