Louisa McRobert, Cathy J. Taylor, Wensheng Deng, Quinton L. Fivelman, Ross M. Cummings, Spencer D. Polley, Oliver Billker, David A. Baker.
PLoS Biol 6, e139 (2008) | doi:10.1371/journal.pbio.0060139
Malaria parasite transmission requires differentiation of male and female gametocytes into gametes within a mosquito following a blood meal. A mosquito-derived molecule, xanthurenic acid (XA), can trigger gametogenesis, but the signalling events controlling this process in the human malaria parasite Plasmodium falciparum remain unknown. A role for cGMP was revealed by our observation that zaprinast (an inhibitor of phosphodiesterases that hydrolyse cGMP) stimulates gametogenesis in the absence of XA. Using cGMP-dependent protein kinase (PKG) inhibitors in conjunction with transgenic parasites expressing an inhibitor-insensitive mutant PKG enzyme, we demonstrate that PKG is essential for XA- and zaprinast-induced gametogenesis. Furthermore, we show that intracellular calcium (Ca2+) is required for differentiation and acts downstream of or in parallel with PKG activation. This work defines a key role for PKG in gametogenesis, elucidates the hierarchy of signalling events governing this process in P. falciparum, and demonstrates the feasibility of selective inhibition of a crucial regulator of the malaria parasite life cycle.# 副作用のないマラリア治療薬に結びつくかも…
# まずはよかった…でも油断は禁物…自然の脆弱さを身を以て覚えましょう
# コラーゲンVIIが作れないのに生きていられるんだ…
# Avian fluっていうよりは手足口病っぽいな
Andrew J. Pask, Kerry J. McInnes, David R. Webb, Roger V. Short.
PLoS ONE 3, e2308 (2008) | doi:10.1371/journal.pone.0002308
With the growing incidence of HIV, there is a desperate need to develop simple, cheap and effective new ways of preventing HIV infection. Male circumcision reduces the risk of infection by about 60%, probably because of the removal of the Langerhans cells which are abundant in the inner foreskin and are the primary route by which HIV enters the penis. Langerhans cells form a vital part of the body's natural defence against HIV and only cause infection when they are exposed to high levels of HIV virions. Rather than removing this natural defence mechanism by circumcision, it may be better to enhance it by thickening the layer of keratin overlying the Langerhans cells, thereby reducing the viral load to which they are exposed. We have investigated the ability of topically administered oestrogen to induce keratinization of the epithelium of the inner foreskin. Histochemically, the whole of the foreskin is richly supplied with oestrogen receptors. The epithelium of the inner foreskin, like the vagina, responds within 24 hours to the topical administration of oestriol by keratinization, and the response persists for at least 5 days after the cessation of the treatment. Oestriol, a cheap, readily available natural oestrogen metabolite, rapidly keratinizes the inner foreskin, the site of HIV entry into the penis. This thickening of the overlying protective layer of keratin should reduce the exposure of the underlying Langerhans cells to HIV virions. This simple treatment could become an adjunct or alternative to surgical circumcision for reducing the incidence of HIV infection in men.# HIV予防には使えそうですが、避妊やその他の性感染症予防には役に立ちませんのであしからず
# 銀河全景…長！
…ダウンロードはこちら# 米国もその気になればこんな感じか…だからって、これを盾に外圧を強められても困るわけだが…
