Search results for "milieu"
showing 10 items of 19813 documents
Density, social information, and space use in the common lizard (Lacerta vivipara)
2007
6 pages; International audience; Socially acquired information is widespread in the animal kingdom. Many individuals make behavioral decisions based on such social information. In particular, individuals may decide to leave or select their habitat based on social information. Few studies have investigated the role of density-related information, a potential social cue about habitat quality in dispersal. Here, we tested for the possibility that the phenotype of intruder common lizards (Lacerta vivipara) may inadvertently carry information about their natal population density. We found that such information use is likely. The behavior of focal lizard was influenced by the natal population den…
Extraction of benzaldehyde from fermentation broth by pervaporation
1996
Abstract The application of pervaporation to extract benzaldehyde produced by microorganisms is considered. A model system was used to study the influence of different parameters and attempts to understand better the mass transfer of this flavour compound. Benzaldehyde was removed from a culture medium from which it was produced by Bjerkandera adusta . The performance of these processes is compared.
Levels of genetic differentiation and gene flow between four populations of the Scaly-naped Pigeon, Patagioenas squamosa : implications for conservat…
2021
Island-endemic columbid species are particularly vulnerable to environmental degradation, extreme climatic events, and interactions with exotic species. The situation might be even more critical in the case of exploited species, where legal hunting and poaching can severely affect population dynamics. Here we document for the first time the genetic structure of the Scaly-naped Pigeon, Patagioenas squamosa, a Caribbean-endemic columbid species of cynegetic interest, over a large part of its range. Using both mitochondrial DNA and nuclear markers (microsatellites), we investigated gene flow, genetic diversity, and genetic structure among four islands populations originating from Puerto-Rico, …
Molecular Bases for Sensitivity to Tubulin-Binding Herbicides in Green Foxtail
2004
Abstract We investigated the molecular bases for resistance to several classes of herbicides that bind tubulins in green foxtail (Setaria viridis L. Beauv.). We identified two α- and two β-tubulin genes in green foxtail. Sequence comparison between resistant and sensitive plants revealed two mutations, a leucine-to-phenylalanine change at position 136 and a threonine-to-isoleucine change at position 239, in the gene encoding α2-tubulin. Association of mutation at position 239 with herbicide resistance was demonstrated using near-isogenic lines derived from interspecific pairings between green foxtail and foxtail millet (Setaria italica L. Beauv.), and herbicide sensitivity bioassays combine…
Evidence for a geranyl-diphosphate synthase located within the plastids of Vitis vinifera L. cultivated in vitro
1992
Intact plastids from cell suspensions of Vitis vinifera L. cv. Muscat de Frontignan, free of detectable contamination by other particles as judged by the distribution of organelle-specific marker enzymes and by electron microscopy, exhibit geranyl-diphosphate synthase activity (EC 2.5.1.1). This synthase activity remains stable after tryptic digestion of unlysed organelles and is enhanced by plastid disruption. We conclude that the enzyme is located within the organelle. The possibility of an isopentenyl diphosphate/dimethylallyl diphosphate translocating system which would play a major role in the regulation of monoterpene metabolism is discussed.
Managing for resilience: an information theory-based approach to assessing ecosystems
2016
Ecosystems are complex and multivariate; hence, methods to assess the dynamics of ecosystems should have the capacity to evaluate multiple indicators simultaneously. Most research on identifying leading indicators of regime shifts has focused on univariate methods and simple models which have limited utility when evaluating real ecosystems, particularly because drivers are often unknown. We discuss some common univariate and multivariate approaches for detecting critical transitions in ecosystems and demonstrate their capabilities via case studies. Synthesis and applications. We illustrate the utility of an information theory-based index for assessing ecosystem dynamics. Trends in this inde…
Male mating success and risk of predation in a wolf spider: a balance between sexual and natural selection?
1998
1. Traits that benefit males through sexual selection are simultaneously expected to impair males by provoking costs through natural selection. If we consider the two male fitness components, mating success and viability, then we may expect that the increase in male mating success resulting from a larger trait size will be counterbalanced by an increase in viability costs. 2. We studied the benefits and costs of male mate searching and sexual signalling activity in the wolf spider Hygrolycosa rubrofasciata. In the field, males search females actively and court them by drumming dry leaves with their abdomen. Females have been shown to prefer males with high drumming rate. Male moving and e…
New national and regional bryophyte records, 43
2015
During the examination of a collection made by the authors in 2009 in San Pedro de Atacama (Antofagasta Region, Chile) one specimen was identified as Bryum incacorralis Herzog, a moss not previously known from Chile (Müller, 2009) and easily confused with some species of Philonotis Brid. (Ochi, 1980). Comparison with the type material confirmed its identity (Holotype: Bolivia, Cochabamba: an Felsen der "Estradillas" bei Incacorral, 3000 m, Herzog s.n., JE! no. 04003475). Bryum incacorralis was first described by Herzog (1909) based on material collected in Cochabamba (Bolivia), and later recorded by Griffin (1977) and O'Shea (2010) from Venezuela. It is placed in the so-called sect. "Alpini…
Evidence for specific, high-affinity binding sites for a proteinaceous elicitor in tobacco plasma membrane
1995
Abstract Binding of cryptogein, a proteinaceous elicitor, was studied on tobacco plasma membrane. The binding of the [125I]cryptogein was saturable, reversible and specific with an apparent Kd of 2 nM. A single class of cryptogein binding sites was found with a sharp optimum pH for binding at about pH 7.0. The high-affinity correlates with cryptogein concentrations required for biological activity in vivo.
Comparison of the effects of cryptogein and oligogalacturonides on tabacco cells and evidence of different forms of desensitization induced by these …
1998
Abstract The effects of cryptogein and oligogalacturonides (OGs) were compared on tobacco cells by measuring calcium influx and calcium-dependent responses including extracellular alkalinization and H 2 O 2 production. The main difference is the higher calcium influx and the sustained H 2 O 2 production induced by cryptogein compared to OGs. Amplitude and duration of calcium signalling triggered by cryptogein or OGs may explain the necrotic effect of cryptogein, and the absence of necrosis in tobacco plants treated with OGs. We used induction of alkalinization and H 2 O 2 production to investigate cryptogein effects after a first treatment with cryptogein or OGs, and reciprocally. Results s…