Search results for "genesis"
showing 10 items of 12136 documents
Karyotype variability and inter-population genomic differences in freshwater ostracods (Crustacea) showing geographical parthenogenesis
2018
Transitions from sexual to asexual reproduction are often associated with polyploidy and increased chromosomal plasticity in asexuals. We investigated chromosomes in the freshwater ostracod species Eucypris virens (Jurine, 1820), where sexual, asexual and mixed populations can be found. Our initial karyotyping of multiple populations from Europe and North Africa, both sexual and asexual, revealed a striking variability in chromosome numbers. This would suggest that chromosomal changes are likely to be accelerated in asexuals because the constraints of meiosis are removed. Hence, we employed comparative genomic hybridization (CGH) within and among sexual and asexual populations to get insigh…
Variation in gene expression within clones of the earthworm Dendrobaena octaedra
2017
Gene expression is highly plastic, which can help organisms to both acclimate and adapt to changing environments. Possible variation in gene expression among individuals with the same genotype (among clones) is not widely considered, even though it could impact the results of studies that focus on gene expression phenotypes, for example studies using clonal lines. We examined the extent of within and between clone variation in gene expression in the earthworm Dendrobaena octaedra, which reproduces through apomictic parthenogenesis. Five microsatellite markers were developed and used to confirm that offspring are genetic clones of their parent. After that, expression of 12 genes was measured…
Epigenetic and Genetic Contributions to Adaptation in Chlamydomonas
2017
Epigenetic modifications, such as DNA methylation or histone modifications, can be transmitted between cellular or organismal generations. However, there are no experiments measuring their role in adaptation, so here we use experimental evolution to investigate how epigenetic variation can contribute to adaptation. We manipulated DNA methylation and histone acetylation in the unicellular green alga Chlamydomonas reinhardtii both genetically and chemically to change the amount of epigenetic variation generated or transmitted in adapting populations in three different environments (salt stress, phosphate starvation, and high CO2) for two hundred asexual generations. We find that reducing the …
New Approaches to Optimize Somatic Embryogenesis in Maritime Pine
2019
Maritime pine (Pinus pinaster Aiton) is a coniferous native of the Mediterranean basin. Because of its adaptability to a wide range of environmental conditions, the species have become a model for studies in coniferous forest management and functional genomics. Somatic embryogenesis (SE) has been so far, the preferred biotechnological strategy for maritime pine breeding programs initiated at the middle-end of the 20th century. To overcome the limitations of the induction and maturation phases in maritime pine SE, we analyzed the possible maternal influence on the embryogenic capability of megagametophytes from controlled crosses, as well as the effect of the temperature and water availabili…
First report of tomato brown rugose fruit virus infecting sweet pepper in Italy
2020
In January 2020, about 85% of a red sweet pepper (Capsicum annuum) crop in a greenhouse located in Ragusa province (Sicily, Italy) showed virus-like symptoms. Symptoms consisted of a slight mosaic and discoloration of young leaves, vein clearing on young leaves, browning of the stem with strong necrosis located in the intersection of the secondary branches, partial necrosis of the vegetative apex and marbling, mosaic and distortion of the fruits (Fig. 1). It is important to note that in 2019 the same greenhouse was cultivated with tomato, which had been removed due to extensive infection caused by Tomato brown rugose fruit virus
Hop stunt viroid: A polyphagous pathogenic RNA that has shed light on viroid–host interactions
2021
[Taxonomy]: Hop stunt viroid (HSVd) is the type species of the genus Hostuviroid (family Pospiviroidae). The other species of this genus is Dahlia latent viroid, which presents an identical central conserved region (CCR) but lacks other structural hallmarks present in Hop stunt viroid. HSVd replication occurs in the nucleus through an asymmetric rolling-circle model as in the other members of the family Pospiviroidae, which also includes the genera Pospiviroid, Cocadviroid, Apscaviroid, and Coleoviroid.
The combined effect on initial glucose concentration and pH control strategies for acetone-butanol-ethanol (ABE) fermentation by Clostridium acetobut…
2021
Abstract The use and depletion of fossil fuels raised the interest in biofuels like biobutanol. Clostridium acetobutylicum DSM 792 is capable of producing biobutanol through ABE fermentation. Butanol production can be influenced by low sugar concentrations, like those obtained after hydrolysis of pre-treated lignocellulosic biomass. This study aimed to evaluate the influence of the initial glucose concentrations (33, 66 and 100 g L−1) and pH control strategies on biobutanol production and glucose consumption. Uncontrolled pH fermentation exhibited low butanol production due to either glucose exhaustion (33 g L−1) or the phenomenon of acid crash (66 and 100 g L−1), which was alleviated by th…
Plants and Arbuscular Mycorrhizal Fungi: Cues and Communication in the Early Steps of Symbiotic Interactions
2007
Abstract The ubiquitous nature of arbuscular mycorrhiza (AM) pleads for common molecular and genetic determinants across different plant taxa. The cellular processes determining compatibility in early interactions prior to and during cell contact between arbuscular mycorrhizal fungi and plant roots are starting to be unraveled. The root epidermis is an active checkpoint where signal exchanges and control over root colonization occur. Root‐secreted flavonoids, flavonols, and strigolactones can act as rhizosphere signals in stimulating presymbiotic fungal growth, although their mechanism of action on the fungal cell is as yet unknown. Likewise, fungal signals (Myc factors) activate early plan…
Effects of peroxidizing herbicides on protoporphyrin IX levels in non-chlorophyllous soybean cell culture
1990
Abstract The mode of action of 16 peroxidizing herbicides belonging to four different families (diphenyl ethers, oxadiazon, pyridine derivatives, and pyrazole derivatives) has been studied in nonchlorophyllous soybean cell cultures. Whenever possible, we have compared active and inactive compounds. Phytotoxic effects were estimated on the basis of growth inhibition, either in the dark or in the light. Protoporphyrin IX accumulations were estimated in dark-treated samples, using a simple methodology. In all cases, we have found a positive correlation between cellular damages and protoporphyrin IX accumulations. The results provide further evidences in favor of the light-dependent activity of…
Mechanisms of Defence to Pathogens : Biochemistry and Physiology
2014
SPE IPM; International audience; Plant defences comprise both pre-existing barriers as well as defences induced upon perception of pathogen-associated molecular patterns (PAMPs) or microbe-associated molecular patterns (MAMPs) or molecules produced from damage as a result of infection (damage-associated molecular patterns (DAMPs)). This chapter focuses on the induced mechanisms of defence. The inducibility of phytoalexin biosynthesis has probably been favoured in the course of evolution by biological constraints such as metabolic costs and functional side-effects associated with chemical defence. Historically, the term ‘hypersensitive’ refers to the rapid and localized cell death induced in…