Control of DEMETER DNA demethylase gene transcription in male and female gamete companion cells in .

The DEMETER (DME) DNA glycosylase initiates active DNA demethylation via the base-excision repair pathway and is vital for reproduction in DME-mediated DNA demethylation is preferentially targeted to small, AT-rich, and nucleosome-depleted euchromatic transposable elements, influencing expression of adjacent genes and leading to imprinting in the endosperm. In the female gametophyte, expression and subsequent genome-wide DNA demethylation are confined to the companion cell of the egg, the central cell. Here, we show that, in the male gametophyte, expression is limited to the companion cell of sperm, the vegetative cell, and to a narrow window of time: immediately after separation of the companion cell lineage from the germline.

Optimized Methods for the Isolation of Female Central Cells and Their Nuclei.

The female gametophyte contains seven cells with eight haploid nuclei buried within layers of sporophytic tissue. Following double fertilization, the egg and central cells of the gametophyte develop into the embryo and endosperm of the seed, respectively. The epigenetic status of the central cell has long presented an enigma due both to its inaccessibility, and the fascinating epigenome of the endosperm, thought to have been inherited from the central cell following activity of the DEMETER demethylase enzyme, prior to fertilization.

Nucleoporin MOS7/Nup88 is required for mitosis in gametogenesis and seed development in Arabidopsis.

Angiosperm reproduction is characterized by alternate diploid sporophytic and haploid gametophytic generations. Gametogenesis shares similarities with that of animals except for the formation of the gametophyte, whereby haploid cells undergo several rounds of postmeiotic mitosis to form gametes and the accessory cells required for successful reproduction. The mechanisms regulating gametophyte development in angiosperms are incompletely understood.

Efficacy of sauchinone as a novel AMPK-activating lignan for preventing iron-induced oxidative stress and liver injury.

Iron-overload disorders cause hepatocyte injury and inflammation by oxidative stress, possibly leading to liver fibrosis and hepatocellular carcinoma. This study investigated the efficacy of sauchinone, a bioactive lignan, in preventing iron-induced liver injury and explored the mechanism of sauchinone's activity. To create iron overload, mice were injected with phenylhydrazine, and the effects on hepatic iron and histopathology were assessed.

Therapeutic potential of dithiolethiones for hepatic diseases.

Comprehensive studies support the notion that oltipraz [4-methyl-5-(2-pyrazynyl)-1,2-dithiole-3-thione] and its congeners exert cancer chemopreventive effects by the prevention, inhibition or reversal of carcinogenic processes. Recently, it was found that dithiolethione compounds had the activities to prevent or treat fibrosis, insulin resistance, and mitochondrial protective effects in the liver by a mechanism involving AMP-activated protein kinase (AMPK) and/or 70-kDa ribosomal protein S6 kinase 1 (S6K1). Moreover, chemical regulation of the AMPK-S6K1 pathway was found to affect Liver X receptor (LXR) activity and lipogenesis, leading to the identification of AMPK and S6K1 as targets for treating hepatic steatosis.

The Emergence of Behavioral Testing of Fishes to Measure Toxicological Effects.

Historically, research in toxicology has utilized non-human mammalian species, particularly rats and mice, to study the effects of toxic exposure on physiology and behavior. However, ethical considerations and the overwhelming increase in the number of chemicals to be screened has led to a shift away from work. The decline in experimentation has been accompanied by an increase in alternative methods for detecting and predicting detrimental effects: experimentation and modeling.