A functional screen for the type III (Hrp) secretome of the plant pathogen Pseudomonas syringae     

Guttman DS  Vinatzer BA  Sarkar SF  Ranall MV  Kettler G  Greenberg JT 《Science (New York, N.Y.)》2002,295(5560):1722-1726

Type III secreted "effector" proteins of bacterial pathogens play central roles in virulence, yet are notoriously difficult to identify. We used an in vivo genetic screen to identify 13 effectors secreted by the type III apparatus (called Hrp, for "hypersensitive response and pathogenicity") of the plant pathogen Pseudomonas syringae. Although sharing little overall homology, the amino-terminal regions of these effectors had strikingly similar amino acid compositions. This feature facilitated the bioinformatic prediction of 38 P. syringae effectors, including 15 previously unknown proteins. The secretion of two of these putative effectors was shown to be type III--dependent. Effectors showed high interstrain variation, supporting a role for some effectors in adaptation to different hosts.  相似文献   

Eastern Indian 3800-million-year-old crust and early mantle differentiation     

Basu AR  Ray SL  Saha AK  Sarkar SN 《Science (New York, N.Y.)》1981,212(4502):1502-1506

Samarium-neodymium data for nine granitic and tonalite gneisses occurring as remnants within the Singhbhum granite batholith in eastern India define an isochron of age 3775 +/- 89 x 10(6) years with an initial (143)Nd/(144)Nd ratio of 0.50798 +/- 0.00007. This age contrasts with the rubidium-strontium age of 3200 x 10(6) years for the same suite of rocks. On the basis of the new samarium-neodynium data, field data, and petrologic data, a scheme of evolution is proposed for the Archean crust in eastern India. The isotopic data provide evidence that parts of the earth's mantle were already differentiated with respect to the chondritic samarium-neodymium ratio 3800 x l0(6) years ago.  相似文献   

Geology. The deadliest intraplate earthquake     

Gupta HK  Rao NP  Rastogi BK  Sarkar D 《Science (New York, N.Y.)》2001,291(5511):2101-2102

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HIV-1 proviral DNA excision using an evolved recombinase     

Sarkar I  Hauber I  Hauber J  Buchholz F 《Science (New York, N.Y.)》2007,316(5833):1912-1915

HIV-1 integrates into the host chromosome and persists as a provirus flanked by long terminal repeats (LTRs). To date, treatment regimens primarily target the virus enzymes or virus-cell fusion, but not the integrated provirus. We report here the substrate-linked protein evolution of a tailored recombinase that recognizes an asymmetric sequence within an HIV-1 LTR. This evolved recombinase efficiently excised integrated HIV proviral DNA from the genome of infected cells. Although a long way from use in the clinic, we speculate that this type of technology might be adapted in future antiretroviral therapies, among other possible uses.  相似文献   

Chemistry. Whence molecular electronics?     

Flood AH  Stoddart JF  Steuerman DW  Heath JR 《Science (New York, N.Y.)》2004,306(5704):2055-2056

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Genotype and hormonal effects on callus formation and regeneration in mulberry     

B. N. Susheelamma  K. Raja Shekar  A. Sarkar  M. R. Rao  R. K. Datta 《Euphytica》1996,90(1):25-29

Summary Twenty-five mulberry genotypes were studied for callus induction, to evaluate the effectiveness of hormones in promoting callus growth and to identify genotypes capable of regenerating plants. Fifteen genotypes showed callus initiation. Genotypic variation was also noted for longevity and rate of growth of callus cultures. Calli of different genotypes were maintained for more than one year. Frequency of callus initiation was high on Murashige & Skoog's modified medium incorporated with 2.0 mg/l 2,4-D, 100 mg/l casein acid hydrolysate and 150 ml/l coconut water. Regeneration through organogenesis was achieved in six genotypes indicating genotypic specificity.  相似文献   

Influence of various dietary synthetic carotenoids on bio-defence mechanisms in rainbow trout, Oncorhynchus mykiss (Walbaum)   总被引：5，自引：0，他引：5  

E C Amar  V Kiron  S Satoh  & T Watanabe 《Aquaculture Research》2001,32(S1):162-173

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Growth and nutrient removal rates of Spirulina platensis and Nostoc muscorum in fish culture effluent: a laboratory-scale study     

Dibyendu Kamilya  Sudipto Sarkar  Tapas K Maiti  Sukumar Bandyopadhyay  & Bimal C Mal 《Aquaculture Research》2006,37(15):1594-1597

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Recent advances in carp seed production and milt cryopreservation     

P. Routray  D. K. Verma  S. K. Sarkar  N. Sarangi 《Fish physiology and biochemistry》2007,33(4):413-427

The fish-seed production industry in India has recorded remarkable growth over the last three decades. The hypophysation technique was successfully introduced into India in 1957 and steady progress towards the refinement of the technique has been registered, which has revolutionized carp seed production in the Indian subcontinent. Advancement of carp maturity through brood stock management and multiple breeding has enabled spawn production well ahead of the monsoon and even beyond, ensuring seed availability throughout the year. The quality of seed is an important consideration for commercial aquaculturists. So, partial stock replenishment in carp hatcheries is practised to overcome the problem of inbreeding, which otherwise leads to poor growth of carps. Similarly, gametes of improved stock are cryopreserved and utilized for quality seed production as well as upgrading the brood stock of carps. The gamete cryopreservation protocol for carps is the focus of this review. An attempt has also been made to incorporate information on carp brood stock management, inducing agents, and seed production, including hatchery management.  相似文献   

Compositional changes of a fuel oil from an oil spill due to natural exposure     

Raymond N. Young  Amar J. Sethi 《Water, air, and soil pollution》1975,5(2):195-205

The purpose of this work was to determine the degree of oil retention from an oil spill area in view of natural physical weathering, and to evaluate the compositional changes of the natural oil retained in the soil material. The percentage of oil retained over the 1 yr period of weathering was determined at various intervals, and the compositional changes were studied by G.L.C. and I.R. The results of G.L.C. indicated the loss of low molecular weight n-paraffins, and that of I.R. indicated the formation of sulfones and ether groups as a result of oxidation reaction due to natural exposure. It was established that up to 4% oil was retained in the soil material after 6 mo of exposure, and that about 3.5% remained after a year.  相似文献