Search results for "Plastic"
showing 10 items of 7296 documents
Water recycling in leaves of Lithops (Aizoaceae)
2016
Lithops plants consist of a pair of succulent leaves inserted on a short stem; each growing season young leaves develop in a cavity formed between the older pair. Young leaves can take up water from the older pair allowing the plant to maintain growth and leaf expansion even without external supply of water. Recycling water between vegetative organs is one of the possible adaptation strategies of plants under drought stress, but it had never been demonstrated experimentally in Lithops. The methodology used to verify the existence of water redistribution from old leaves to young leaves was fluorescence microscopy, using two dyes to follow the water pathway inside the plant: Sulforhodamine G …
Collateral sensitivity of natural products in drug-resistant cancer cells
2018
Cancer chemotherapy is frequently hampered by drug resistance. Concepts to combine anticancer drugs with different modes of action to avoid the development of resistance did not provide the expected success in the past, because tumors can be simultaneously non-responsive to many drugs (e.g. the multidrug resistance phenotype). However, tumors may be specifically hypersensitive to other drugs - a phenomenon also termed collateral sensitivity. This seems to be a general biological mechanism, since it also occurs in drug-resistant Escherichia coli and Saccharomyces cerevisiae. Here, we give a timely and comprehensive overview on hypersensitivity in resistant cancer cells towards natural produc…
Assessing the impact of lanthanum on the bivalve Corbicula fluminea in the Rhine River
2018
Abstract Anthropogenic lanthanum predominantly derived from a point source has become an emerging contaminant in the Rhine River, but little is known about its ecotoxicological consequences on bivalve mollusks. A fundamental requirement of aquatic invertebrate adaptation and survival in stressful habitats is the maintenance of energy homeostasis. As such, the present study tested the impact of four dissolved La concentrations (0, 50, 100 and 200 μM) on the energy balance of the bivalve Corbicula fluminea in the Rhine River. Bivalves were collected at four sampling sites which were contaminated by La to different degrees, thereby allowing to understand the degree of their potential acclimati…
Bioplastic recovery from wastewater: A new protocol for polyhydroxyalkanoates (PHA) extraction from mixed microbial cultures
2019
Abstract A new protocol for polyhydroxyalkanoates (PHA) extraction from mixed microbial cultures (MMCs) is proposed. PHA-accumulating capacity of the MMC was selected in a sequencing batch reactor (SBR) fed with a synthetic effluent emulating a fermented oil mill wastewater (OMW). The highest recovery yield and purity (74 ± 8% and 100 ± 5%, respectively) was obtained when using NH4-Laurate for which operating conditions of the extraction process such as temperature, concentration and contact time were optimized. Best conditions for PHA extraction from MMC turned to be: i) a pre-treatment with NaClO at 85 °C with 1 h of contact time, followed by ii) a treatment with lauric acid in a ratio ac…
Epigenetic control of phenotypic plasticity in a filamentous fungus Neurospora crassa
2016
AbstractPhenotypic plasticity is the ability of a genotype to produce different phenotypes under different environmental or developmental conditions. Phenotypic plasticity is an ubiquitous feature of living organisms, and is typically based on variable patterns of gene expression. However, the mechanisms by which gene expression is influenced and regulated during plastic responses are poorly understood in most organisms. While modifications to DNA and histone proteins have been implicated as likely candidates for generating and regulating phenotypic plasticity, specific details of each modification and its mode of operation have remained largely unknown. In this study, we investigated how e…
Genotypic and phenotypic variation in transmission traits of a complex life cycle parasite
2013
Characterizing genetic variation in parasite transmission traits and its contribution to parasite vigor is essential for understanding the evolution of parasite life‐history traits. We measured genetic variation in output, activity, survival, and infection success of clonal transmission stages (cercaria larvae) of a complex life cycle parasite (Diplostomum pseudospathaceum). We further tested if variation in host nutritional stage had an effect on these traits by keeping hosts on limited or ad libitum diet. The traits we measured were highly variable among parasite genotypes indicating significant genetic variation in these life‐history traits. Traits were also phenotypically variable, for …
Controversy over the Mode of Growth of Cambial Cylinder
2021
Based on mathematical modelling, this review article describes the mechanism of expansion in the circumference of vascular cambium due to radial growth leading to increase in the tree-trunk diameter, and emphasizes upon the huge difference in the rate of symplastic growth of cambial initials in two different directions, viz. radial and circumferential. On the basis of anatomical evidence regarding the role of symplastic and intrusive growths, the long-standing hypothesis that the intrusive growth contributes to the increase of cambium circumference has been falsified. It has been shown with the help of mathematical calculations as well as anatomical observations that only symplastic growth …
Stress for invasion success? Temperature stress of preceding generations modifies the response to insecticide stress in an invasive pest insect
2012
Adaptation to stressful environments is one important factor influencing species invasion success. Tolerance to one stress may be complicated by exposure to other stressors experienced by the preceding generations. We studied whether parental temperature stress affects tolerance to insecticide in the invasive Colorado potato beetle Leptinotarsa decemlineata. Field-collected pyrethroid-resistant beetles were reared under either stressful (17°C) or favourable (23°C) insecticide-free environments for three generations. Then, larvae were exposed to pyrethroid insecticides in common garden conditions (23°C). Beetles were in general tolerant to stress. The parental temperature stress alone affect…
Biogeochemical cycling and ecological thresholds in a High Arctic lake (Svalbard)
2019
Lakes are a dominant feature of the Arctic landscape and a focal point of regional and global biogeochemical cycling. We collected a sediment core from a High Arctic Lake in southwestern Svalbard for multiproxy paleolimnological analysis. The aim was to find linkages between the terrestrial and aquatic environments in the context of climate change to understand centennial-long Arctic biogeochemical cycling and environmental dynamics. Two significant thresholds in elemental cycling were found based on sediment physical and biogeochemical proxies that were associated with the end of the cold Little Ice Age and the recent warming. We found major shifts in diatom, chironomid and cladoceran comm…
Intraspecific variability in host manipulation by parasites
2011
8 pages; International audience; Manipulative parasites have the capacity to alter a broad range of phenotypic traits in their hosts, extending from colour, morphology and behaviour. While significant attention has been devoted to describing the diversity of host manipulation among parasite clades, and testing the adaptive value of phenotypic traits that can be manipulated, there is increasing evidence that variation exists in the frequency and intensity of the changes displayed by parasitized individuals within single host-manipulative parasite systems. Such variability occurs within individuals, between individuals of a same population, and across populations. Here we review the non-genet…