Transgenerational maintenance of transgene body CG but not CHG and CHH methylation

In plants, RNA-directed DNA methylation (RdDM) can target both transgene promoters and coding regions/gene bodies. RdDM leads to methylation of cytosines in all sequence contexts: CG, CHG and CHH. Upon segregation of the RdDM trigger, at least CG methylation can be maintained at promoter regions in the progeny. So far, it is not clear whether coding region methylation can be also maintained. We showed that the body of Potato spindle tuber viroid (PSTVd) transgene constructs became densely de novo methylated at CG, CHG and CHH sites upon PSTVd infection. In this study, we demonstrate that in viroid-free progeny plants, asymmetric CHH and CHG methylation was completely lost. However, symmetric CG methylation was stably maintained for at least two generations. Importantly, the presence of transgene body methylation did not lead to an increase of dimethylation of histone H3 lysine 9 or a decrease of acetylation of H3. Our data supports the view that CG methylation can be maintained not only in promoters but also in the body of transgenes. They further suggest that maintenance of methylation may occur independently of tested chromatin modifications.     

Salinity effects on maturation, reproductive and life span characteristics of four Egyptian Artemia populations (International Study on Artemia. LXVIII)

Three parthenogenetic Artemia populations, i.e. two coastal from Borg El-Arab and El-Max saltworks and one from the inland Qarun Lake, and a bisexual strain (Artemia salina) from the inland carbonate lake of Wadi El-Natrun, all from upper Egypt were assayed for their response in 5 salinities (i.e. 35, 80, 120, 150 and 200 g l^?1). The experimental procedure was carried out under laboratory conditions, where the effects of salinity on maturation and ten reproductive and life span characteristics were investigated. The parthenogenetic Egyptian populations are more euryhaline compared to the bisexual one. The two coastal parthenogenetic populations appeared to be very similar in maturation rate and reproductive output at all salinities tested. The inland asexual strain showed a different reproductive response to the elevation of salinity from the two coastal populations. Discriminant function analysis has proven to be a useful tool in determining the differential response of closely related Artemia populations. The bisexual population showed significantly lower reproductive output compared to the parthenogenetic ones and performed best at 35 g l^?1; this is the first record of an A. salina population inhabiting a carbonate lake. These findings may provide valuable information on Artemia biodiversity in an area where very little is known. %     

An increased number of circulating γ/δ TCR + T cells in patients with chronic viral hepatitis

Abstract There is evidence that γ/δ TCR + T cells are specialized in recognizing different antigens, but their immunologic role as a second TCR is still unclear. The aim of this study was to investigate the percentage and absolute numbers of circulating γ/δ TCR + T cells in patients with chronic viral hepatitis (CVH) and to compare with HBsAg⁺, HCV healthy carriers and healthy subjects. Forty nine patients with CVH-24 with chronic active (CAH) and 25 with chronic persistent hepatitis (CPH)-, 21 HBsAg⁺, 20 HCV asymptomatic carriers and 20 healthy subjects were enrolled in the study. Lymphocyte subsets were determined after incubation with monoclonal antibodies to T total (CD5) and T γ/δ cells (γ/δ-1) using immunofluorescence microscopy. An increased number of circulating γ/δ TCR + T cells was found in patients with CVH in comparison with asymptomatic carriers and normal controls: this increase was more profound in patients with CAH, compared to CPH patients. These results indicate a correlation between circulating γ/δ TCR + T cells in CVH patients and activity and chronicity of the disease.