Search results for "etics"

2021

Although insect herbivores are known to evolve resistance to insecticides through multiple genetic mechanisms, resistance in individual species has been assumed to follow the same mechanism. While both mutations in the target site insensitivity and increased amplification are known to contribute to insecticide resistance, little is known about the degree to which geographic populations of the same species differ at the target site in a response to insecticides. We tested structural (e.g., mutation profiles) and regulatory (e.g., the gene expression of Ldace1 and Ldace2, AChE activity) differences between two populations (Vermont, USA and Belchow, Poland) of the Colorado potato beetle, Lepti…

Magnesium ions promote assembly of channel-like structures from beticolin 0, a non-peptide fungal toxin purified from Cercospora beticola.

1998

Beticolins are toxins produced by the fungus Cercospora beticola. Using beticolin 0 (B0), we have produced a strong and Mg(2+)-dependent increase in the membrane conductance of Arabidopsis protoplasts and Xenopus oocytes. In protein-free artificial bilayers, discrete deflexions of current were observed (12 pS unitary conductance in symmetrical 100 mM KCl) in the presence of B0 (approximately 10 microM) and in the presence of nominal Mg2+. Addition of 50 microM Mg2+ induced a macroscopic current which could be reversed to single channel current by chelating Mg2+ with EDTA. Both unitary and macroscopic currents were ohmic. The increase in conductance of biological membranes triggered by B0 is…

Constitutive expression of clathrin hub hinders elicitor-induced clathrin-mediated endocytosis and defense gene expression in plant cells.

2012

International audience; Endocytosis has been recently implicated in the signaling network associated with the recognition of microbes by plants. In a previous study, we showed that the elicitor cryptogein was able to induce clathrin-mediated endocytosis (CME) in tobacco suspension cells. Herein, we investigate further the induced CME by means of a GFP-tagged clathrin light chain and a CME inhibitor, the hub domain of clathrin heavy chain. Hub constitutive expression does affect neither cell growth nor constitutive endocytosis but abolishes cryptogein-induced CME. Such an inhibition has no impact on early events in the cryptogein signaling pathway but reduces the expression of defense-associ…

EST based phylogenomics of Syndermata questions monophyly of Eurotatoria

2008

Abstract Background The metazoan taxon Syndermata comprising Rotifera (in the classical sense of Monogononta+Bdelloidea+Seisonidea) and Acanthocephala has raised several hypotheses connected to the phylogeny of these animal groups and the included subtaxa. While the monophyletic origin of Syndermata and Acanthocephala is well established based on morphological and molecular data, the phylogenetic position of Syndermata within Spiralia, the monophyletic origin of Monogononta, Bdelloidea, and Seisonidea and the acanthocephalan sister group are still a matter of debate. The comparison of the alternative hypotheses suggests that testing the phylogenetic validity of Eurotatoria (Monogononta+Bdel…

The light-harvesting system of Euglena gracilis during the cell cycle

1989

The apoproteins of the light-harvesting chlorophyll-protein complexes LHCI and CP29 (apparent molecular weights of 27 kDa and 29 kDa, respectively) of Euglena gracilis were identified immunologically. Both complexes are present in the thylakoids of autotrophically cultured Euglena cells during the whole cell cycle. The relative amount of each apoprotein tends to increase towards the end of the cell cycle. The light-harvesting chlorophyll-protein complex of photosystem II, LHCII, of E. gracilis contains chlorophyll a, chlorophyll b, neoxanthin, diadinoxanthin and beta-carotene. Its chlorophyll a/b ratio is about 1.7 during the whole cell cycle. About 9 h after cell division the ratio of diad…

Tamarix arborea var. arborea and Tamarix parviflora: Two species valued for their adaptability to stress conditions.

2016

The choice of stress resistant and highly adaptable species is a fundamental step for landscaping and ornamental purposes in arid and coastal environments such as those in the Mediterranean basin. The genus Tamarix L. includes about 90 species with a high endurance of adversity. We investigated the water relations and photosynthetic response of Tamarix arborea (Sieb. ex Ehrenb.) Bge. var. arborea and T. parviflora DC. growing in an urban environment. Both species showed no evidence of drought or salt stress in summer, and appeared to follow two strategies with T. arborea var. arborea investing in high carbon gain at the beginning of the summer, and then reducing photosynthetic activity at t…

The tropical African genus Morgenia (Orthoptera, Tettigoniidae, Phaneropterinae) with emphasis on the spur at the mid tibia

2018

The authors revised the genus Morgenia Karsch, 1890 which now consists of eight species, of which three are here newly described (Morgeniaplurimaculata Massa & Moulin, sp. n., M.angustipinnata Massa, sp. n., and M.lehmannorum Heller & Massa, sp. n.). Six of the eight species occur in the Tri National Sangha (TNS) comprising Dzanga-Sangha Special Reserve and Dzanga Ndoki National Park (Central African Republic), whose high biodiversity has been recently highlighted. In particular the genus is characterised by the presence of a more or less long spur at the inner mid tibia, different in each species; in M.modulata, it moved lower down into a new position at about ¼ of tibia, w…

Cytological and molecular characterization of three gametoclones of Citrus clementina

2013

Abstract Background Three gametoclonal plants of Citrus clementina Hort. ex Tan., cv. Nules, designated ESP, FRA, and ITA (derived from three labs in Spain, France, and Italy, respectively), were selected for cytological and molecular characterization in order to elucidate genomic rearrangements provoked by haploidization. The study included comparisons of their ploidy, homozygosity, genome integrity, and gene dosage, using chromosome counting, flow cytometry, SSR marker genotyping, and array-Comparative Genomic Hybridization (array-CGH). Results Chromosome counting and flow cytometry revealed that ESP and FRA were haploid, but ITA was tri-haploid. Homozygous patterns, represented by a sing…

Predator–vole interactions in northern Europe: the role of small mustelids revised

2014

The cyclic population dynamics of vole and predator communities is a key phenomenon in northern ecosystems, and it appears to be influenced by climate change. Reports of collapsing rodent cycles have attributed the changes to warmer winters, which weaken the interaction between voles and their specialist subnivean predators. Using population data collected throughout Finland during 1986–2011, we analyse the spatio-temporal variation in the interactions between populations of voles and specialist, generalist and avian predators, and investigate by simulations the roles of the different predators in the vole cycle. We test the hypothesis that vole population cyclicity is dependent on predator…

From arctic lemmings to adaptive dynamics: Charles Elton's legacy in population ecology.

2001

We shall examine the impact of Charles S. Elton's 1924 article on periodic fluctuations in animal populations on the development of modern population ecology. We argue that his impact has been substantial and that during the past 75 years of research on multi-annual periodic fluctuations in numbers of voles, lemmings, hares, lynx and game animals he has contributed much to the contemporary understanding of the causes and consequences of population regulation. Elton was convinced that the cause of the regular fluctuations was climatic variation. To support this conclusion, he examined long-term population data then available. Despite his firm belief in a climatic cause of the self-repeating …