Search results for "reo"

2019

Revision of the calcareous fen arachnofauna: habitat affinities of the fen-inhabiting spiders

2018

Calcareous fens are one of the most species-rich habitats of the temperate zone of the Northern Hemisphere. In spite of this species richness, however, calcareous fens are still rather poorly investigated. Consequently, the data of the fen-associated spider fauna are also largely lacking. The aim of the research was to study the spider fauna of the calcareous fens of Latvia and to draw conclusions about what kind of spider species and ecological groups typically inhabit calcareous fen habitats. Spiders were sampled in the summer months of 2010, 2011, and 2012 at nine different calcareous fens of the coastal lowland of Latvia. The spider collection was performed by pitfall traps and a sweep …

The tiny eukaryote Ostreococcus provides genomic insights into the paradox of plankton speciation

2007

The smallest known eukaryotes, at ≈1-μm diameter, are Ostreococcus tauri and related species of marine phytoplankton. The genome of Ostreococcus lucimarinus has been completed and compared with that of O. tauri . This comparison reveals surprising differences across orthologous chromosomes in the two species from highly syntenic chromosomes in most cases to chromosomes with almost no similarity. Species divergence in these phytoplankton is occurring through multiple mechanisms acting differently on different chromosomes and likely including acquisition of new genes through horizontal gene transfer. We speculate that this latter process may be involved in altering the cell-surface character…

Artemisia arborescens essential oil composition, enantiomeric distribution and antimicrobial activity from different wild populations from the Medite…

2016

International audience; Aerial parts of Artemisiaarborescens were collected from different sites of the Mediterranean area (southwestern Algeria and southern Italy) and the chemical composition of their essential oil (EO) extracted by hydrodistillation was studied by both gas chromatography (GC) equipped with an enantioselective capillary column and GC/mass spectrometry (GC/MS). The EOs obtained were tested against several Listeriamonocytogenes strains. Using GC and GC/MS, 41 compounds were identified, accounting for 96.0-98.8% of the total EO. All EOs showed a similar terpene profile, which was rich in chamazulene, -thujone, and camphor. However, the concentration of such compounds varied …

Can number and size of offspring increase simultaneously?--a central life-history trade-off reconsidered.

2011

Abstract Background To maximize their fitness, parents are assumed to allocate their resources optimally between number and size of offspring. Although this fundamental life-history trade-off has been subject to long standing interest, its genetic basis, especially in wild mammals, still remains unresolved. One important reason for this problem is that a large multigenerational pedigree is required to conduct a reliable analysis of this trade-off. Results We used the REML-animal model to estimate genetic parameters for litter size and individual birth size for a common Palearctic small mammal, the bank vole (Myodes glareolus). Even though a phenotypic trade-off between offspring number and …

Kinetic studies on protoporphyrinogen oxidase inhibition by diphenyl ether herbicides

1991

Diphenyl ethers (DPEs) and related herbicides are powerful inhibitors of protoporphyrinogen oxidase, an enzyme involved in the biosynthesis of haems and chlorophylls. The inhibition kinetics of protoporphyrinogen oxidase of various origins by four DPEs, (methyl)-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (acifluorfen and its methyl ester, acifluorfen-methyl), methyl-5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-chlorobenzoate (LS 820340) and methyl-5-[2-chloro-5-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (RH 5348), were studied. The inhibitions of the enzymes from maize (Zea mays) mitochondrial and etiochloroplastic membranes and mouse liver mitochondrial membranes were com…

Characterization of (3H) acifluorfen binding to purified pea etioplasts, and evidence that protoporphyrinogen oxidase specifically binds acifluorfen

1992

It is now generally accepted that protoporphyrinogen oxidase is the target-enzyme for diphenylether-type herbicides. Recent studies [Camadro, J-M., Matringe, M., Scalla, R. & Labbe, P. (1991) Biochem. J. 277, 17–21] have revealed that in maize, diphenyl ethers competitively inhibit protoporphyrinogen oxidase with respect to its substrate, protoporphyrinogen IX. In this study, we show that, in purified pea etioplast, [3H]acifluorfen specifically binds to a single class of high-affinity binding sites with an apparent dissociation constant of 6.2 ± 1.3 nM and a maximum density of 29 ± 5 nmol/g protein. [3H]Acifluorfen binding reaches equilibrium in about 1 min at 30°C. Half dissociation occurs…

Purification and characterization of geranyl diphosphate synthase from Vitis vinifera L. cv Muscat de Frontignant cell cultures

1993

A geranyl diphosphate synthase (EC 2.5.1.1), which catalyzes the formation of geranyl diphosphate from dimethylallyl diphosphate and isopentenyl diphosphate, was isolated from Vitis vinifera L. cv Muscat de Frontignan cell cultures. Purification of the enzyme was achieved successively by ammonium sulfate precipitation and chromatography on DEAE-Sephacel, hydroxylapatite, Mono Q, Phenyl Superose, Superose 12, and preparative nondenaturing polyacrylamide gels. The enzyme formed only geranyl diphosphate as a product. In all cases, neither neryl diphosphate, the cis isomer, nor farnesyl diphosphate was detected. The enzyme showed a native molecular mass of 68 [plus or minus] 5 kD as determined …

Conservation implications of change in antipredator behavior in fragmented habitat: Boreal rodent, the bank vole, as an experimental model

2015

Abstract Habitat fragmentation is known to cause population declines but the mechanisms leading to the decline are not fully understood. Fragmentation is likely to lead to changes in predation risk, which may cause behavioral responses with possible population level consequences. It has recently been shown that the awareness of predator presence, resulting in a fear response, strongly affects behavior and physiology of the prey individuals. Costs arising from fear may be as important for the prey population size as the direct killing of prey. We tested how predation risk in the form of scent of a specialist predator, the least weasel (Mustela nivalis nivalis), affects bank vole (Myodes glar…

Seaweed fails to prevent ocean acidification impact on foraminifera along a shallow-water CO2 gradient

2014

Ocean acidification causes biodiversity loss, alters ecosystems, and may impact food security, as shells of small organisms dissolve easily in corrosive waters. There is a suggestion that photosynthetic organisms could mitigate ocean acidification on a local scale, through seagrass protection or seaweed cultivation, as net ecosystem organic production raises the saturation state of calcium carbonate making seawater less corrosive. Here, we used a natural gradient in calcium carbonate saturation, caused by shallow-water CO2 seeps in the Mediterranean Sea, to assess whether seaweed that is resistant to acidification (Padina pavonica) could prevent adverse effects of acidification on epiphytic…