Novel facultative Methylocella strains are active methane consumers at terrestrial natural gas seeps

Natural gas seeps contribute to global climate change by releasing substantial amounts of the potent greenhouse gas methane and other climate-active gases including ethane and propane to the atmosphere. However, methanotrophs, bacteria capable of utilising methane as the sole source of carbon and energy, play a significant role in reducing the emissions of methane from many environments. Methylocella-like facultative methanotrophs are a unique group of bacteria that grow on other components of natural gas (i.e. ethane and propane) in addition to methane but a little is known about the distribution and activity of Methylocella in the environment. The purposes of this study were to identify bacteria involved in cycling methane emitted from natural gas seeps and, most importantly, to investigate if Methylocella-like facultative methanotrophs were active utilisers of natural gas at seep sites

The desmosome and pemphigus

Desmosomes are patch-like intercellular adhering junctions (“maculae adherentes”), which, in concert with the related adherens junctions, provide the mechanical strength to intercellular adhesion. Therefore, it is not surprising that desmosomes are abundant in tissues subjected to significant mechanical stress such as stratified epithelia and myocardium. Desmosomal adhesion is based on the Ca2+-dependent, homo- and heterophilic transinteraction of cadherin-type adhesion molecules. Desmosomal cadherins are anchored to the intermediate filament cytoskeleton by adaptor proteins of the armadillo and plakin families. Desmosomes are dynamic structures subjected to regulation and are therefore targets of signalling pathways, which control their molecular composition and adhesive properties. Moreover, evidence is emerging that desmosomal components themselves take part in outside-in signalling under physiologic and pathologic conditions. Disturbed desmosomal adhesion contributes to the pathogenesis of a number of diseases such as pemphigus, which is caused by autoantibodies against desmosomal cadherins. Beside pemphigus, desmosome-associated diseases are caused by other mechanisms such as genetic defects or bacterial toxins. Because most of these diseases affect the skin, desmosomes are interesting not only for cell biologists who are inspired by their complex structure and molecular composition, but also for clinical physicians who are confronted with patients suffering from severe blistering skin diseases such as pemphigus. To develop disease-specific therapeutic approaches, more insights into the molecular composition and regulation of desmosomes are required

On the Tropical Origins of the Alps

A remarkable colonial encounter took place on 26 February 1896 on the south-eastern peninsula of Celebes — one of the many so-called outer islands in the far-flung Dutch Asian Empire. Two wealthy Swiss naturalists, Paul and Fritz Sarasin, the first Europeans to explore this large hitherto ‘unknown’ island, reached the summit of one of the mountains in the highlands. At 1000 metres above sea level they were rewarded with a surprising view. A large lake ‘gleaming in magnificent blue’ lay before them. ‘Delighted by this discovery we hurried down to the lakeside where yet another surprise awaited us. A real, inhabited village with houses built on piles arose from the water, a village named Matanna.’1 The Sarasins’ excitement grew even further as they found out that the lake dwellers on Celebes ‘practised a curious form of pottery with products reminding us of identical objects from Swiss lake dwellers’.2 It is important to note the asymmetry of this comparison. The Sarasins were not referring to contemporary Swiss lake dwellers. In fact there were no people living in lakes in Switzerland around 1900. The reference was to prehistoric lake dwellers, whose poles and material remains Swiss archaeologists had started digging up from the mud of the lakeshores a few decades earlier. What the Sarasins thought they had discovered on the shores of Lake Matanna was thus a piece of living prehistory on a tropical island which, to them, in many ways resembled Switzerland