A giant virus in amoebae     

La Scola B  Audic S  Robert C  Jungang L  de Lamballerie X  Drancourt M  Birtles R  Claverie JM  Raoult D 《Science (New York, N.Y.)》2003,299(5615):2033

  相似文献   

Resistance Evaluation of Some Hybrid Rice, Conventional Early Indica and Late Japonica Rice to Magnaporthe grisea     

SHEN Ying  Adreit Henry  ZHU Xu-dong  Milazzo Joelle  CHEN Hong-qi  Tharreau Didier 《中国农业科学(英文版)》2003,2(12)

Thirty isolates of Magnaporthe grisea collected from 18 provinces/cities representing 21 pathotypes and 9 different lineages were inoculated to rice varieties with known resistance genes and some hybrid rices,conventional early indica and late japonica varieties cultivated recently in China.Virulence spectrum of the 30 isolates was very different,showing that they recognize numerous different resistance genes.Varieties also revealed very different resistance patterns showing that they carry different resistance genes or combinations of resistance genes.On the basis of comparisons with international differential varieties with known resistance genes,resistance genes in certain Chinese varieties could be speculated.The results indicated that some of them were resistant to most of the isolates tested and that they could be of interest as resistance sources for hybrid parents or to be planted in the field directly.  相似文献   

A cellular framework for gut-looping morphogenesis in zebrafish     

Horne-Badovinac S  Rebagliati M  Stainier DY 《Science (New York, N.Y.)》2003,302(5645):662-665

Many vertebrate organs adopt asymmetric positions with respect to the midline, but little is known about the cellular changes and tissue movements that occur downstream of left-right gene expression to produce this asymmetry. Here, we provide evidence that the looping of the zebrafish gut results from the asymmetric migration of the neighboring lateral plate mesoderm (LPM). Mutations that disrupt the epithelial structure of the LPM perturb this asymmetric migration and inhibit gut looping. Asymmetric LPM migration still occurs when the endoderm is ablated from the gut-looping region, suggesting that the LPM can autonomously provide a motive force for gut displacement. Finally, reducing left-sided Nodal activity randomizes the pattern of LPM migration and gut looping. These results reveal a cellular framework for the regulation of organ laterality by asymmetrically expressed genes.  相似文献   

Antimicrobial peptides keep insect endosymbionts under control     

Login FH  Balmand S  Vallier A  Vincent-Monégat C  Vigneron A  Weiss-Gayet M  Rochat D  Heddi A 《Science (New York, N.Y.)》2011,334(6054):362-365

Vertically transmitted endosymbionts persist for millions of years in invertebrates and play an important role in animal evolution. However, the functional basis underlying the maintenance of these long-term resident bacteria is unknown. We report that the weevil coleoptericin-A (ColA) antimicrobial peptide selectively targets endosymbionts within the bacteriocytes and regulates their growth through the inhibition of cell division. Silencing the colA gene with RNA interference resulted in a decrease in size of the giant filamentous endosymbionts, which escaped from the bacteriocytes and spread into insect tissues. Although this family of peptides is commonly linked with microbe clearance, this work shows that endosymbiosis benefits from ColA, suggesting that long-term host-symbiont coevolution might have shaped immune effectors for symbiont maintenance.  相似文献   

Microbe interactions undermine predictions     

Raoult D 《Science (New York, N.Y.)》2011,331(6014):144-5; author reply 145-7

  相似文献   

Virology. Picking the right spot     

Trono D 《Science (New York, N.Y.)》2003,300(5626):1670-1671

  相似文献   

A rule-based method for the development of crop management systems applied to grain sorghum in south-western France     

Philippe Debaeke  Jean-Marie Nolot  Didier Raffaillac 《Agricultural Systems》2006,90(1-3):180-201

A generic approach is proposed for the development and testing of crop management systems in contrasting situations of water availability. Ecophysiological knowledge, expertise, regional references and simulation models are combined to devise management strategies adapted to production targets and constraints. The next stage consists of converting these crop management strategies into logical and consistent sets of decision rules. Each rule describes the reasoning which is used to apply a technical decision by taking account of observed or simulated environmental conditions or predicted agronomic risks.

This approach was applied to design crop management systems for grain sorghum (Sorghum bicolor L. Moench.) in south-western France. For spring-sown crops, management (sowing date, plant density, varietal choice, N fertilizer rate and timing) was based on water availability, both for economic and environmental reasons. Specific sets of decision rules were written for irrigated and rainfed conditions. The establishment of rules was based on agronomic principles (e.g. for plant density) or on the application of a simulation model (e.g. for sowing date, variety). N fertilization and irrigation were applied using combined N and water dynamic models.

A novel methodology combining crop diagnosis, analytical trials and crop simulation was developed to evaluate the management systems. An irrigated and a rainfed rule-based management system were compared near Toulouse (S.W. France) from 1995 to 2002. The profitability of rainfed low-input management was confirmed for sorghum in spite of high yields under irrigation (up to 10 t ha⁻¹). The adaptation of sorghum management in rainfed conditions was mainly achieved through early maturing cultivars and by reducing N applications by 65%.  相似文献   

Variation and phylogeny of the ribosomal DNA unit types and 5 S DNA inPetunia Jussieu     

Asmâa Kabbaj  Fatiha Zeboudj  Didier Peltier  Abderrahmane Tagmount  Michel Tersac  Hubert Dulieu  André Bervillé 《Genetic Resources and Crop Evolution》1995,42(4):311-325

Summary Seven wildPetunia species including 2n = 18 species (P. parviflora Jussieu,P. linearis Hook.) and those with 2n = 14 (P. parodii Steene,P. axillaris Lam.,P. integrifolia Hook.,P. inflata R.E. Fries,P. violacea Lindl.) and tenPetunia hybrida horticultural lines were compared for polymorphisms in rDNA genes using the four restriction enzymesEcoRI,BamHI,HindIII andXhoI. All the unit types found in the lines pre-existed in the wild forms. There are two different sizes of either 11.45 or 11.6 kb./The 2n = 18 species are closely related to the 2n = 14 species, thus making thePetunia genus homogeneous. Moreover, it is likely thatP. hybrida lines originated in several kinds of crosses between these species. We constructed a dendrogram for all the 15 rDNA unit types found. Two main branches of the tree result from the presence or the absence ofHindIII sites. The main branch is divided according to variability at theEcoRI andBamHI sites. Taking into account the existence of several loci which carry one unit type only, we consider whether or not exchanges might occur between loci. Lines carrying two unit types and lines carrying three unit types support such a hypothesis.XhoI andBamHI fragments enable us to distinguish two types of 5S DNA corresponding to 2n = 18 and 2n = 14 species, respectively.P. hybrida lines and each 2n = 14 wild species carry one of the types only, that corresponds to one 5S DNA locus. The most parsimonious phylogenetic trees whatever the species chosen as the outgroup, do not fit with our knowledge ofPetunia and with taxonomy. This is likely because only few loci formed the basis of these phylogenetic constructions.  相似文献   

Effects of tree canopy composition on earthworms and other macro-invertebrates in beech forests of Upper Normandy (France): The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002     

Michaël Aubert  Mickaël Hedde  Thibaud Decaëns  Fabrice Bureau  Pierre Margerie  Didier Alard 《Pedobiologia》2003,47(5-6):904-912

  相似文献   

Granulomatous mural folliculitis in a dog treated with ciclosporin and methotrexate     

Pauline Panzuti  Marion Mosca  Didier Pin 《Veterinary dermatology》2020,31(2):170-e35

  相似文献