23 research outputs found
Sensory Perception of Food and Insulin-Like Signals Influence Seizure Susceptibility
Food deprivation is known to affect physiology and behavior. Changes that occur could be the result of the organism's monitoring of internal and external nutrient availability. In C. elegans, male mating is dependent on food availability; food-deprived males mate with lower efficiency compared to their well-fed counterparts, suggesting that the mating circuit is repressed in low-food environments. This behavioral response could be mediated by sensory neurons exposed to the environment or by internal metabolic cues. We demonstrated that food-deprivation negatively regulates sex-muscle excitability through the activity of chemosensory neurons and insulin-like signaling. Specifically, we found that the repressive effects of food deprivation on the mating circuit can be partially blocked by placing males on inedible food, E. coli that can be sensed but not eaten. We determined that the olfactory AWC neurons actively suppress sex-muscle excitability in response to food deprivation. In addition, we demonstrated that loss of insulin-like receptor (DAF-2) signaling in the sex muscles blocks the ability of food deprivation to suppress the mating circuit. During low-food conditions, we propose that increased activity by specific olfactory neurons (AWCs) leads to the release of neuroendocrine signals, including insulin-like ligands. Insulin-like receptor signaling in the sex muscles then reduces cell excitability via activation of downstream molecules, including PLC-γ and CaMKII
Differences in two-component signal transduction proteins among the genus Brucella: implications for host preference and pathogenesis
Identification, characterization, and in situ detection of a fruit-body-specific hydrophobin of Pleurotus ostreatus
Apparent Obligatory Dependence of Peptidoglycan Synthesis on Phospholipid Synthesis Studied in Ether-Treated Escherichia coli
Identification, characterization, and in situ detection of a fruit-body-specific hydrophobin of Pleurotus ostreatus
Identification, characterization, and in situ detection of a fruit-body-specific hydrophobin of Pleurotus ostreatus
Hydrophobins are small (length, about 100 +/- 25 amino acids), cysteine-rich, hydrophobic proteins that are present in large amounts in fungal cell walls, where they form part of the outermost layer (rodlet layer); sometimes, they can also be secreted into the medium, Different hydrophobins are associated with different developmental stages of a fungus, and their biological functions include protection of the hyphae against desiccation and attack by either bacterial or fungal parasites, hyphal adherence, and the lowering of surface tension of the culture medium to permit aerial growth of the hyphae. We identified and isolated a hydrophobin (fruit body hydrophobin 1 [Fbh1]) present in fruit bodies but absent in both monokaryotic and dikaryotic mycelia of the edible mushroom Pleurotus ostreatus. In order to study the temporal and spatial expression of the fbh1 gene, we determined the N-terminal amino acid sequence of Fbh1. We also synthesized and cloned the double-stranded cDNA corresponding to the full-length mRNA of Fbh1 to use it as a probe in both Northern blot and in situ hybridization experiments. Fbh1 mRNA is detectable in specific parts of the fruit body, and it is absent in other developmental stages
Transposon-associated epigenetic silencing during Pleurotus ostreatus life cycle
Transposable elements constitute an important fraction of eukaryotic genomes.
Given their mutagenic potential, host-genomes have evolved epigenetic defense
mechanisms to limit their expansion. In fungi, epigenetic modifications have been
widely studied in ascomycetes, although we lack a global picture of the
epigenetic landscape in basidiomycetes. In this study, we analysed the
genome-wide epigenetic and transcriptional patterns of the white-rot
basidiomycete Pleurotus ostreatus throughout its life cycle. Our results
performed by using high-throughput sequencing analyses revealed that
strain-specific DNA methylation profiles are primarily involved in the repression
of transposon activity and suggest that 21 nt small RNAs play a key role in
transposon silencing. Furthermore, we provide evidence that transposon-associated
DNA methylation, but not sRNA production, is directly involved in the silencing
of genes surrounded by transposons. Remarkably, we found that nucleus-specific
methylation levels varied in dikaryotic strains sharing identical genetic
complement but different subculture conditions. Finally, we identified key genes
activated in the fruiting process through the comparative analysis of
transcriptomes. This study provides an integrated picture of epigenetic defense
mechanisms leading to the transcriptional silencing of transposons and
surrounding genes in basidiomycetes. Moreover, our findings suggest that
transcriptional but not methylation reprogramming triggers fruitbody development
in P. ostreatus