科研人員分離出了一種此前未知的真菌,，它被認(rèn)為是驅(qū)動(dòng)著歐洲西北部的火蠑螈種群走向幾乎滅絕的原因。真菌疾病壺菌病是由水生真菌蛙壺菌（Batrachochytrium dendrobatidis，Bd）引起的，它已經(jīng)在20世紀(jì)90年代以來導(dǎo)致了全球200多種兩棲動(dòng)物的衰退。但是并非所有兩棲動(dòng)物的死亡都與蛙壺菌有關(guān),。An Martel及其同事尋找了困擾著當(dāng)?shù)鼗鹣旙ⅲ⊿alamandra salamandra）種群的這種神秘病原體，并且發(fā)現(xiàn)了第二種蛙壺菌致病病原體：一種壺菌真菌，作者將其命名為Batrachochytrium salamandrivorans sp. nov,。這組作者報(bào)告說,，從這種全球衰退當(dāng)中死亡的火蠑螈的皮膚損傷中分離出的這些真菌看上去為寄生在脊椎動(dòng)物身上做好了準(zhǔn)備。這些真菌比蛙壺菌喜歡更涼爽的氣候,，在50到59華氏度之間生長得最好,，并且無法在華氏77度以上的溫度下生存。這項(xiàng)研究發(fā)現(xiàn),，實(shí)驗(yàn)性地讓產(chǎn)婆蟾感染了B. salamandrivorans,，結(jié)果表明它能抵抗這種迅速殺死其他兩棲動(dòng)物的侵蝕性的皮膚疾病。這組作者說,，這些發(fā)現(xiàn)提示B. salamandrivorans與其親緣關(guān)系相近的蛙壺菌相比,，它可能在兩棲動(dòng)物世界中占據(jù)了一個(gè)不同的生態(tài)位。（生物谷 Bioon.com）
生物谷推薦的英文報(bào)道
Fire salamanders, recognisable by their distinctive yellow and black skin patterns, have been found dead in the country's forests since 2010. The population has fallen to around 10 individuals, less than four per cent of its original level, but what has been killing them has been a mystery until now.
Scientists from Ghent University, Imperial College London, Vrije Universiteit Brussel and the Dutch conservation group Ravon have isolated a new species of fungus from the dead animals and found that it can rapidly kill fire salamanders. They have named the fungus Batrachochytrium salamandrivorans, the second part meaning "salamander-eating," and report their findings today in the Proceedings of the National Academy of Sciences.
Fungi are increasingly recognised as important threats to biodiversity. A species related to the new fungus, Batrachochytrium dendrobatidis (Bd), has plagued amphibian populations across the globe and is thought to have wiped out more than 200 species worldwide. It causes the disease chytridiomycosis, which the International union for the Conservation of Nature has called the single most devastating infectious disease in vertebrate animals.
The study's lead author, Professor An Martel from the University of Ghent, said: "In several regions, including northern Europe, amphibians appeared to be able to co-exist with Bd. It is therefore extremely worrying that a new fungus has emerged that causes mass mortalities in regions where amphibian populations were previously healthy."
Co-author Professor Matthew Fisher, from Imperial College London, said: "It is a complete mystery why we are seeing this outbreak now, and one explanation is that the new salamander-killing fungus has invaded the Netherlands from elsewhere in the world. We need to know if this is the case, why it is so virulent, and what its impact on amphibian communities will be on a local and global scale. Our experience with Bd has shown that fungal diseases can spread between amphibian populations across the world very quickly. We need to act urgently to determine what populations are in danger and how best to protect them."
The fungus can be passed between salamanders by direct contact, and possibly by indirect contact although this hasn't been proven. It invades the animal's skin, eventually destroying it completely. In tests, the fungus was not able to infect midwife toads, which have been threatened by chytridiomycosis, but whether other species might be vulnerable is unknown.
The scientists have brought surviving salamanders into captivity to protect the remaining population in the Netherlands. To aid further studies, they have also developed a diagnostic tool that enables the new fungus to be quickly identified. They tested 100 salamanders from Belgium, where the population has remained healthy, but so far there is no sign that the fungus has spread beyond the Netherlands.
The research was funded by the Royal Zoological Society of Antwerp, the European Research Council and Biodiversa.
