Role of the Arabidopsis glucose sensor HXK1 in nutrient,light, and hormonal signaling     

Moore B  Zhou L  Rolland F  Hall Q  Cheng WH  Liu YX  Hwang I  Jones T  Sheen J 《Science (New York, N.Y.)》2003,300(5617):332-336

Glucose modulates many vital processes in photosynthetic plants. Analyses of Arabidopsis glucose insensitive2 (gin2) mutants define the physiological functions of a specific hexokinase (HXK1) in the plant glucose-signaling network. HXK1 coordinates intrinsic signals with extrinsic light intensity. HXK1 mutants lacking catalytic activity still support various signaling functions in gene expression, cell proliferation, root and inflorescence growth, and leaf expansion and senescence, thus demonstrating the uncoupling of glucose signaling from glucose metabolism. The gin2 mutants are also insensitive to auxin and hypersensitive to cytokinin. Plants use HXK as a glucose sensor to interrelate nutrient, light, and hormone signaling networks for controlling growth and development in response to the changing environment.  相似文献   

Leiomodin is an actin filament nucleator in muscle cells     

Chereau D  Boczkowska M  Skwarek-Maruszewska A  Fujiwara I  Hayes DB  Rebowski G  Lappalainen P  Pollard TD  Dominguez R 《Science (New York, N.Y.)》2008,320(5873):239-243

Initiation of actin polymerization in cells requires nucleation factors. Here we describe an actin-binding protein, leiomodin, that acted as a strong filament nucleator in muscle cells. Leiomodin shared two actin-binding sites with the filament pointed end-capping protein tropomodulin: a flexible N-terminal region and a leucine-rich repeat domain. Leiomodin also contained a C-terminal extension of 150 residues. The smallest fragment with strong nucleation activity included the leucine-rich repeat and C-terminal extension. The N-terminal region enhanced the nucleation activity threefold and recruited tropomyosin, which weakly stimulated nucleation and mediated localization of leiomodin to the middle of muscle sarcomeres. Knocking down leiomodin severely compromised sarcomere assembly in cultured muscle cells, which suggests a role for leiomodin in the nucleation of tropomyosin-decorated filaments in muscles.  相似文献   

Reduction of theta rhythm dissociates grid cell spatial periodicity from directional tuning     

Brandon MP  Bogaard AR  Libby CP  Connerney MA  Gupta K  Hasselmo ME 《Science (New York, N.Y.)》2011,332(6029):595-599

Grid cells recorded in the medial entorhinal cortex of freely moving rats exhibit firing at regular spatial locations and temporal modulation with theta rhythm oscillations (4 to 11 hertz). We analyzed grid cell spatial coding during reduction of network theta rhythm oscillations caused by medial septum (MS) inactivation with muscimol. During MS inactivation, grid cells lost their spatial periodicity, whereas head-direction cells maintained their selectivity. Conjunctive grid-by-head-direction cells lost grid cell spatial periodicity but retained head-direction specificity. All cells showed reduced rhythmicity in autocorrelations and cross-correlations. This supports the hypothesis that spatial coding by grid cells requires theta oscillations, and dissociates the mechanisms underlying the generation of entorhinal grid cell periodicity and head-direction selectivity.  相似文献   

Chimpanzee reservoirs of pandemic and nonpandemic HIV-1     

Keele BF  Van Heuverswyn F  Li Y  Bailes E  Takehisa J  Santiago ML  Bibollet-Ruche F  Chen Y  Wain LV  Liegeois F  Loul S  Ngole EM  Bienvenue Y  Delaporte E  Brookfield JF  Sharp PM  Shaw GM  Peeters M  Hahn BH 《Science (New York, N.Y.)》2006,313(5786):523-526

Human immunodeficiency virus type 1 (HIV-1), the cause of human acquired immunodeficiency syndrome (AIDS), is a zoonotic infection of staggering proportions and social impact. Yet uncertainty persists regarding its natural reservoir. The virus most closely related to HIV-1 is a simian immunodeficiency virus (SIV) thus far identified only in captive members of the chimpanzee subspecies Pan troglodytes troglodytes. Here we report the detection of SIVcpz antibodies and nucleic acids in fecal samples from wild-living P. t. troglodytes apes in southern Cameroon, where prevalence rates in some communities reached 29 to 35%. By sequence analysis of endemic SIVcpz strains, we could trace the origins of pandemic (group M) and nonpandemic (group N) HIV-1 to distinct, geographically isolated chimpanzee communities. These findings establish P. t. troglodytes as a natural reservoir of HIV-1.  相似文献   

Inflammatory polyp trapped in the oesophagus of a cat          下载免费PDF全文

P. Sebastian  E. Dominguez  I. Espada  L. Fresno  R. Novellas 《The Journal of small animal practice》2017,58(12):726-726

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Mineral Composition of Uroliths Obtained from Sheep and Goats with Obstructive Urolithiasis          下载免费PDF全文

M.L. Jones  P.M. Gibbons  A.J. Roussel  B.J. Dominguez 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2017,31(4):1202-1208

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Survey of the plant-available silicon status of agricultural soils in Louisiana     

Tapasya Babu  Lawrence Datnoff  Payton Dupree  Brandon White 《Journal of plant nutrition》2018,41(3):273-287

Adequate silicon nutrition in plants has shown positive effects on the growth and yield of the crop and physico-chemical properties of the soil. Hence, this study was initiated to survey the plant-available silicon in the agricultural soils of different parishes of Louisiana. Soil samples were collected from 212 representative agricultural fields of 27 agrarian parishes of Louisiana. Poor correlations between deionized water, calcium chloride, and other extractants suggest that the unbuffered calcium chloride extraction may reflect only a transient status of soil soluble silicon similar to deionized water extraction procedure. Also, acetic acid-2 extraction procedure may reflect the net effects of the sorption/desorption reactions by extracting the readily as well as the slowly releasable silicon that control solubility, thus giving a true measure of current availability. Compared to the previously established critical soil silicon levels, several agricultural fields of Louisiana were deemed to be low in plant-available silicon.  相似文献   

Isolation of a phytotoxic isocoumarin from Diaporthe eres‐infected Hedera helix (English ivy) and synthesis of its phytotoxic analogs          下载免费PDF全文

Kumudini M Meepagala  William E Briscoe  Natascha Techen  Robert D Johnson  Brandon M Clausen  Stephen O Duke 《Pest management science》2018,74(1):37-45

BACKGROUND

The fungus Diaporthe eres was isolated from a fungal pathogen‐infected leaf of Hedera helix (English ivy) exhibiting necrosis. It is hypothesized that the causative fungus produces phytotoxins as evidenced by necrotic lesions on the leaves.

RESULTS

The fungus was isolated and grown in Czapek Dox broth culture medium and potato dextrose broth culture medium and identified as Diaporthe eres. The ethyl acetate extracts of the culture broths were phytotoxic to lettuce (Lactuca sativa) and bentgrass (Agrostis stolonifera). 3,4‐Dihydro‐8‐hydroxy‐3,5‐dimethylisocoumarin ( 1 ) and tyrosol ( 2 ) were isolated and identified as the phytotoxic constituents. Six analogs of 3,4‐dihydro‐isocoumarin were synthesized and shown to be phytotoxic. The synthesized 3,4‐dihydro‐8‐hydroxy‐3,7‐dimethylisocoumarin and 3,4‐dihydro‐8‐hydroxy‐3,3,7‐trimethylisocoumarin were two‐ to three‐fold more phytotoxic than the naturally occurring 1 in a Lemna paucicostata growth bioassay.

CONCLUSION

Synthesis and herbicidal activities of the several new analogs of 1 are reported for the first time. These promising molecules should be used as templates for synthesis and testing of more analogs. © 2017 Society of Chemical Industry  相似文献