CASTS VS. CYLINDROIDS     

Alexander J  Connolly JM 《Science (New York, N.Y.)》1923,58(1491):68-69

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Genome sequence of Theileria parva, a bovine pathogen that transforms lymphocytes     

Gardner MJ  Bishop R  Shah T  de Villiers EP  Carlton JM  Hall N  Ren Q  Paulsen IT  Pain A  Berriman M  Wilson RJ  Sato S  Ralph SA  Mann DJ  Xiong Z  Shallom SJ  Weidman J  Jiang L  Lynn J  Weaver B  Shoaibi A  Domingo AR  Wasawo D  Crabtree J  Wortman JR  Haas B  Angiuoli SV  Creasy TH  Lu C  Suh B  Silva JC  Utterback TR  Feldblyum TV  Pertea M  Allen J  Nierman WC  Taracha EL  Salzberg SL  White OR  Fitzhugh HA  Morzaria S  Venter JC  Fraser CM  Nene V 《Science (New York, N.Y.)》2005,309(5731):134-137

We report the genome sequence of Theileria parva, an apicomplexan pathogen causing economic losses to smallholder farmers in Africa. The parasite chromosomes exhibit limited conservation of gene synteny with Plasmodium falciparum, and its plastid-like genome represents the first example where all apicoplast genes are encoded on one DNA strand. We tentatively identify proteins that facilitate parasite segregation during host cell cytokinesis and contribute to persistent infection of transformed host cells. Several biosynthetic pathways are incomplete or absent, suggesting substantial metabolic dependence on the host cell. One protein family that may generate parasite antigenic diversity is not telomere-associated.  相似文献   

SOY-BEAN PASTE AS AN EMULSIFYING AGENT     

Field AM  Alexander BH  Sylvanus EB 《Science (New York, N.Y.)》1933,77(1986):91-92

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Requirement of JNK2 for scavenger receptor A-mediated foam cell formation in atherogenesis   总被引：1，自引：0，他引：1  

Ricci R  Sumara G  Sumara I  Rozenberg I  Kurrer M  Akhmedov A  Hersberger M  Eriksson U  Eberli FR  Becher B  Borén J  Chen M  Cybulsky MI  Moore KJ  Freeman MW  Wagner EF  Matter CM  Lüscher TF 《Science (New York, N.Y.)》2004,306(5701):1558-1561

In vitro studies suggest a role for c-Jun N-terminal kinases (JNKs) in proatherogenic cellular processes. We show that atherosclerosis-prone ApoE-/- mice simultaneously lacking JNK2 (ApoE-/- JNK2-/- mice), but not ApoE-/- JNK1-/- mice, developed less atherosclerosis than do ApoE-/- mice. Pharmacological inhibition of JNK activity efficiently reduced plaque formation. Macrophages lacking JNK2 displayed suppressed foam cell formation caused by defective uptake and degradation of modified lipoproteins and showed increased amounts of the modified lipoprotein-binding and -internalizing scavenger receptor A (SR-A), whose phosphorylation was markedly decreased. Macrophage-restricted deletion of JNK2 was sufficient to decrease atherogenesis. Thus, JNK2-dependent phosphorylation of SR-A promotes uptake of lipids in macrophages, thereby regulating foam cell formation, a critical step in atherogenesis.  相似文献   

Breakdown of the Born-Oppenheimer approximation in the F+ o-D2 -> DF + D reaction     

Che L  Ren Z  Wang X  Dong W  Dai D  Wang X  Zhang DH  Yang X  Sheng L  Li G  Werner HJ  Lique F  Alexander MH 《Science (New York, N.Y.)》2007,317(5841):1061-1064

The reaction of F with H2 and its isotopomers is the paradigm for an exothermic triatomic abstraction reaction. In a crossed-beam scattering experiment, we determined relative integral and differential cross sections for reaction of the ground F(2P(3/2)) and excited F*(2P(1/2)) spin-orbit states with D2 for collision energies of 0.25 to 1.2 kilocalorie/mole. At the lowest collision energy, F* is approximately 1.6 times more reactive than F, although reaction of F* is forbidden within the Born-Oppenheimer (BO) approximation. As the collision energy increases, the BO-allowed reaction rapidly dominates. We found excellent agreement between multistate, quantum reactive scattering calculations and both the measured energy dependence of the F*/F reactivity ratio and the differential cross sections. This agreement confirms the fundamental understanding of the factors controlling electronic nonadiabaticity in abstraction reactions.  相似文献   

Protection from chemotherapy-induced alopecia in a rat model   总被引：7，自引：0，他引：7  

A M Hussein  J J Jimenez  C A McCall  A A Yunis 《Science (New York, N.Y.)》1990,249(4976):1564-1566

Alopecia (hair loss) is among the most distressing side effects of cancer chemotherapy. Little progress has been made, however, in its prevention or treatment, partly because of the lack of suitable experimental model. In recent work on the treatment of myelogenous leukemia in the rat, the following observations were made: (i) treatment of 8-day-old rats with cytosine arabinoside consistently produced alopecia, and (ii) ImuVert, a biologic response modifier derived from the bacterium Serratia marcescens, uniformly produced complete protection against the alopecia. In subsequent experiments, both cyclophosphamide and doxorubicin also produced alopecia in this model, and the doxorubicin-induced alopecia was prevented by treatment with ImuVert. The potential relevance of these observations to chemotherapy-induced alopecia in the clinical setting should be examined.  相似文献   

H2S: a universal defense against antibiotics in bacteria   总被引：1，自引：0，他引：1  

Shatalin K  Shatalina E  Mironov A  Nudler E 《Science (New York, N.Y.)》2011,334(6058):986-990

Many prokaryotic species generate hydrogen sulfide (H(2)S) in their natural environments. However, the biochemistry and physiological role of this gas in nonsulfur bacteria remain largely unknown. Here we demonstrate that inactivation of putative cystathionine β-synthase, cystathionine γ-lyase, or 3-mercaptopyruvate sulfurtransferase in Bacillus anthracis, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli suppresses H(2)S production, rendering these pathogens highly sensitive to a multitude of antibiotics. Exogenous H(2)S suppresses this effect. Moreover, in bacteria that normally produce H(2)S and nitric oxide, these two gases act synergistically to sustain growth. The mechanism of gas-mediated antibiotic resistance relies on mitigation of oxidative stress imposed by antibiotics.  相似文献   

Layer-by-layer removal of graphene for device patterning     

Dimiev A  Kosynkin DV  Sinitskii A  Slesarev A  Sun Z  Tour JM 《Science (New York, N.Y.)》2011,331(6021):1168-1172

The patterning of graphene is useful in fabricating electronic devices, but existing methods do not allow control of the number of layers of graphene that are removed. We show that sputter-coating graphene and graphene-like materials with zinc and dissolving the latter with dilute acid removes one graphene layer and leaves the lower layers intact. The method works with the four different types of graphene and graphene-like materials: graphene oxide, chemically converted graphene, chemical vapor-deposited graphene, and micromechanically cleaved ("clear-tape") graphene. On the basis of our data, the top graphene layer is damaged by the sputtering process, and the acid treatment removes the damaged layer of carbon. When used with predesigned zinc patterns, this method can be viewed as lithography that etches the sample with single-atomic-layer resolution.  相似文献   

Response: water quality     

Smith RA  Alexander RB  Wolman MG 《Science (New York, N.Y.)》1987,237(4810):11

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THE AWARD OF THE NOBEL PRIZE TO PROFESSOR HABER     

Alexander J 《Science (New York, N.Y.)》1920,51(1318):348

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