Search results for "Date"

Sex versus parthenogenesis: A transcriptomic approach of photoperiod response in the model aphid Acyrthosiphon pisum (Hemiptera: Aphididae)

2007

International audience; Most aphids develop a cyclic parthenogenesis life-cycle. After several generations of viviparous parthenogenetic females, it follows a single annual generation of sexual individuals, usually in autumn, that mate and lay the sexual eggs. Shortening of photoperiod at the end of the summer is a key factor inducing the sexual response. With the survey here reported we aimed at identifying a collection of candidate genes to participate at some point in the cascade of events that lead to the sexual phenotypes. Following a suppression subtractive hybridization methodology (SSH) on the model aphid Acyrthosiphon pisum, we built and characterised two reciprocal cDNA libraries …

Towards food, feed and energy crops mitigating climate change

2011

Agriculture is an important source of anthropogenic emissions of the greenhouse gases (GHG), methane (CH 4 ) and nitrous oxide (N 2 O), and crops can affect the microbial processes controlling these emissions in many ways. Here, we summarize the current knowledge of plant–microbe interactions in relation to the CH 4 and N 2 O budgets and show how this is promoting new generations of crop cultivars that have the potential to mitigate GHG emissions for future agricultural use. The possibility of breeding low GHG-emitting cultivars is a paradigm shift towards sustainable agriculture that balances climate change and food and bioenergy security.

Mycelial development of Fusarium oxysporum in the vicinity of tomato roots

1999

The patterns of mycelial development (length and branching) of five strains of Fusarium oxysporum were measured in the vicinity of tomato and wheat roots. Two strains were of f. sp. lycopersici, two of f. sp. radicis-lycopersici and the fifth was a non-pathogenic strain currently used as a biocontrol agent. Hyphal extension and branching were measured microscopically using a CCD camera and an image analyser. Furthermore, the role of soluble root exudates, insoluble root materials, glucose supply, and nitrogen supply (casamino acids) on mycelial development was investigated. Each strain had its own pattern of development in the absence of a root. Fungal development of all five strains was st…

Catalogue of the Egyptian Ephydroidea (Diptera: Schizophora: Acalyptratae)

2018

We present a catalogue of all known taxa of the superfamily Ephydroidea in Egypt. Old World synonymies, type localities, type depositories, world distributions by biogeographic realm(s) and country, Egyptian localities and dates of collection are provided. A total number of 117 species belonging to 45 genera, 18 tribes, 7 subfamilies, and representing 3 families has been catalogued. The treated families are: Ephydridae (shore flies or brine flies), Drosophilidae (vinegar flies or fruit flies) and Braulidae (bee lice). One shore fly species, Psilopa clara (Wollaston, 1858), is recorded for the first time from Egypt. Two new synonyms of shore flies are proposed, namely: Philotelma ulianai Raf…

Genomic Analysis of European Drosophila melanogaster Populations Reveals Longitudinal Structure, Continent-Wide Selection, and Previously Unknown DNA…

2020

Genetic variation is the fuel of evolution, with standing genetic variation especially important for short-term evolution and local adaptation. To date, studies of spatiotemporal patterns of genetic variation in natural populations have been challenging, as comprehensive sampling is logistically difficult, and sequencing of entire populations costly. Here, we address these issues using a collaborative approach, sequencing 48 pooled population samples from 32 locations, and perform the first continent-wide genomic analysis of genetic variation in European Drosophila melanogaster. Our analyses uncover longitudinal population structure, provide evidence for continent-wide selective sweeps, ide…

2021

Abstract Insect cuticular hydrocarbons (CHCs) are highly diverse and have multiple functions, including communication and waterproofing. CHC profiles form species-specific, complex blends of up to 150 compounds. Especially in ants, even closely related species can have largely different profiles, raising the question how CHC differences are mirrored in the regulation of biosynthetic pathways. The neotropical ants Crematogaster levior and Camponotus femoratus both consist of two cryptic species each that are morphologically similar, but express strongly different CHC profiles. This is ideal to study the molecular basis of CHC differences. We thus investigated gene expression differences in f…

Phosphorylated intermediate of a transport ATPase and activity of protein kinase in membranes from corn roots

1983

A maize-root microsomal fraction was enriched in ATPase by treatment with Triton X-100. This activity, which reached 1.2-2.0/mumol Pi x min-1 x mg protein-1, was specific for ATP, very slightly stimulated by K+, inhibited by orthovanadate and diethylstilbestrol, resistant to oligomycin and azide, and had a Km of 1.2 mM MgATP. Incubation of the microsomal fraction with [gamma 32-P]ATP followed by electrophoresis in acid conditions revealed the presence of several phosphoproteins. The phosphorylation of a 110000-Mr polypeptide reached the steady-state level in less than 5 s and rapidly turned over the phosphate group. The phosphorylation level was an hyperbolic function of the [ATP] with a Km…

Inhibition of adenosine trephosphatase activity from a plasma membrane fraction of acer pseudoplatanus cells by 2,2,2-trichloroethyl 3,4-dichlorocarb…

1986

2,2,2-Trichloroethyl 3,4-dichlorocarbanilate (SW26) is toxic for Acer pseudoplatanus cell cultures. It inhibited the cellular proton extrusion and depolarized the plasmalemma. In vitro, it inhibited the plasma membrane ATPase. SW 26 was also inhibitory to membrane ATPases of other origins-plant (maize shoot), fungus (Schizosaccharomyces pombe), and animal (dog kidney)-with about the same efficiency (7.5 micromolar < I(50) < 22 micromolar). It did not inhibit the oligomycin-sensitive ATPase from purified plant mitochondria, nor molybdate-sensitive soluble phosphatases. SW26 was more specific for plasma membrane ATPases than diethylstilbestrol or vanadate. A Lineweaver-Burk plot analysis show…

Cercospora beticola Toxin Inhibits Vanadate-Sensitive H+ Transport in Corn Root Membrane Vesicles

1988

The effect of Cercospora beticola toxin on the transport of protons by vanadate-sensitive ATPase was studied with corn (Zea mays) root microsomal vesicles prepared by differential centrifugation, sedimentation through a sucrose cushion, and washing with Triton X-100 plus KBr. In these preparations, addition of ATP induced intravesicular H(+)-accumulation as evidenced by a rapid quenching of the fluorescence of 9-amino-6-chloro-2-methoxy acridine. This quenching was relatively unaffected by inhibitors of mitochondrial and tonoplast-type ATPases, but was strongly reduced by inhibitors of plasma membrane H(+)-ATPase. C. beticola toxin markedly inhibited ATP dependent H(+)-transport, and this e…

Integrative taxonomy demonstrates the unexpected synonymy between two predatory mite species: Cydnodromus idaeus and C. picanus (Acari: Phytoseiidae)

2011

Contact: tixier@supagro.inra.fr; Species of the mite family Phytoseiidae are well known as predators of mite pests all over the world. Their identification is thus of great interest for biological control. The specimens examined in this study belong to the species Cydnodromus idaeus (described from Brazil) and C. picanus (described from Chile). They were collected together on the same plant in Argentina. These species are mainly differentiated by the presence/absence of the dorsal solenostomes (gland openings) gd2. Some morphometric differences were observed between the Argentinian specimens and the type material of C. idaeus and C. picanus; however, they were not sufficient to support a sp…