Search results for "Class"
showing 10 items of 38174 documents
Identification, characterization and analysis of expression of genes encoding arylalkylamine N-acetyltransferases in the pea aphidAcyrthosiphon pisum
2013
Most organisms exhibit some kind of rhythmicity in their behaviour and/or physiology as an adaptation to the cyclical movements of the Earth. In addition to circadian rhythms, many organisms have an annual rhythmicity in certain activities, such as reproduction, migration or induction of diapause. Current knowledge of the molecular basis controlling seasonal rhythmicity, especially in insects, is scarce. One element that seems to play an essential role in the maintenance of both circadian and seasonal rhythms in vertebrates is the hormone melatonin. In vertebrates, the limiting enzyme in its synthesis is the arylalkylamine N-acetyltransferase (AANAT). Melatonin is also present in insects bu…
Photoperiodic effects on diapause-associated gene expression trajectories in EuropeanLeptinotarsa decemlineatapopulations
2014
Behavioural and physiological changes during diapause, an important strategy of insects for surviving harsh seasonal conditions, have been intensively studied. The genetic and molecular mechanisms underpinning diapause development are less well known. We took a candidate gene approach to study prediapause gene expression patterns in the Colorado potato beetle (Leptinotarsa decemlineata), an invasive insect that has rapidly spread northwards to high seasonality environments. Newly eclosed beetles originating from southern (Italy) and northern (Russia) Europe were reared under short- [12 h light (L):12 h dark (D)] and long-day (18L:6D) photoperiods for 10 days. This time period includes the s…
Chronic toxicity of diazinon todaphnia magna:Effects on survival, reproduction and growth
1995
The sublethal effect of 0.15, 0.18, 0.22, 0.25 and 0.30 μg/L diazinon on the survival, reproduction and growth of D. magna was monitored for 21 days. Neonates (≤ 24 h) were obtained from the stock cultures and raised individually in 50 mL glass beakers. All daphnids were transfered every other day to a new beaker containing fresh medium, food and the appropriate pesticide concentration. The animals were maintained in an environmental chamber at 22±1°C on a 12L: 12D photoperiod and were fed daily on 5 x 105 cell/mL of the green algae Nannochloris oculata. The parameters used to determine the effect of the pesticide on reproduction were: mean total young per female, mean brood size, mean numb…
Photoperiodic regulation of life-history traits before and after eclosion: egg-to-adult development time, juvenile body weight and reproductive diapa…
2012
Photoperiod is the main environmental cue used by northern insects to predict the forthcoming seasonal changes and to adjust their life-history traits to fit these changes. We studied the effects of photoperiod on egg-to-adult development time, juvenile body mass and female reproductive diapause in two northern Drosophila montana populations with different patterns of voltinism. The most interesting findings were consistent between the populations: (1) when maintained before eclosion in short day conditions, representing early autumn, the flies developed faster and were lighter than when maintained in long day conditions, representing early summer, (2) photoperiodic time measurement is appa…
The role of light in the emergence of weeds: using Camelina microcarpa as an example
2015
When modelling the emergence of weeds, two main factors are considered that condition this process: temperature and soil moisture. Optimum temperature is necessary for metabolic processes that generate energy for growth, while turgor pressure is necessary for root and shoot elongation which eventually leads to seedling emergence from the soil. Most emergence models do not usually consider light as a residual factor, but it could have an important role as it can alter directly or indirectly the dormancy and germination of seeds. In this paper, inclusion of light as an additional factor to photoperiod and radiation in emergence models is explored and compared with the classical hydrothermal t…
Deregulated Copper Transport Affects Arabidopsis Development Especially in the Absence of Environmental Cycles
2010
Abstract Copper is an essential cofactor for key processes in plants, but it exerts harmful effects when in excess. Previous work has shown that the Arabidopsis (Arabidopsis thaliana) COPT1 high-affinity copper transport protein participates in copper uptake through plant root tips. Here, we show that COPT1 protein localizes to the plasma membrane of Arabidopsis cells and the phenotypic effects of transgenic plants overexpressing either COPT1 or COPT3, the latter being another high-affinity copper transport protein family member. Both transgenic lines exhibit increased endogenous copper levels and are sensitive to the copper in the growth medium. Additional phenotypes include decreased hypo…
Somatic Embryogenesis and Plant Regeneration from Hypocotyl Cultures of Digitalis obscura L.
1986
Summary Hypocotyl sections from 20-day-old seedlings of Digitalis obscura L. were used to examine the effect of IAA on somatic embryogenesis. Although embryogenesis was obtained with all IAA concentrations (0.1, 0.5 and 1 ppm) and under both illumination conditions tested (16 h photoperiod and darkness), incubation in photoperiod increased yield of embryos and shortened the embryo induction time. Optimum results were obtained with 1 ppm IAA. About 30 % of the embryos obtained developed into complete plantlets when transferred to basal medium without growth regulators.
Northern Drosophila montana flies show variation both within and between cline populations in the critical day length evoking reproductive diapause
2013
Reproductive diapause, and its correct timing, plays an important role in the life cycle of many insect species living in a seasonally varying environment at high latitudes. In the present paper we have documented variation in the critical day length (CDL) for adult reproductive diapause and the steepness of photoperiodic response curves (PPRCs) in seven clinal populations of Drosophila montana in Finland between the latitudes 61 and 67°N, paying special attention to variation in these traits within and between cline populations. The isofemale lines representing these populations showed a sharp transition from 0% to 100% in females' diapause incidence in the shortening day lengths, indicate…
Modulation of Efficient Diiodo-BODIPY in vitro Phototoxicity to Cancer Cells by Carbon Nano-Onions
2020
Photodynamic therapy (PDT) is currently one of the most promising approaches for targeted cancer treatment. It is based on responses of vital physiological signals, namely reactive oxygen species (ROS), which are associated with diseased condition development, such as tumors. This study presents the synthesis, incorporation, and application of a diiodo-BODIPY based photosensitizer, based on a non-covalent functionalization of carbon nano-onions (CNOs). In vitro assays demonstrate that HeLa cells internalize the diiodo-BODIPY molecules, and their CNOs nanohybrids. Upon cell internalization and light exposure, the pyrene-diiodo-BODIPY molecules induce an increase of the ROS level of HeLa cell…
TRAIL acts synergistically with iron oxide nanocluster-mediated magneto- and photothermia
2019
International audience; Targeting TRAIL (Tumor necrosis factor (TNF)-Related Apoptosis-Inducing Ligand) receptors for cancer therapy remains challenging due to tumor cell resistance and poor preparations of TRAIL or its derivatives. Herein, to optimize its therapeutic use, TRAIL was grafted onto iron oxide nanoclusters (NCs) with the aim of increasing its pro-apoptotic potential through nanoparticle-mediated magnetic hyperthermia (MHT) or photothermia (PT). Methods: The nanovector, NC@TRAIL, was characterized in terms of size, grafting efficiency, and potential for MHT and PT. The therapeutic function was assessed on a TRAIL-resistant breast cancer cell line, MDA-MB-231, wild type (WT) or T…