Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand

Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55-75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18-25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with increased sequences from Aquificaceae, supports a role for methyltransferase in thermophilic arsenic resistance. Our study highlights microbial contributions to coupled arsenic and sulfur cycling at Champagne Pool, with implications for understanding the evolution of microbial arsenic resistance in sulfidic geothermal systems

The effects of different arsenic species in relation to straighthead disease in rice

The effects of inorganic arsenic on plants, the mechanisms involved in the uptake and transport of arsenic and how inorganic arsenic enters food chains are well documented. Regulatory limits have been established to control the inorganic arsenic concentrations in certain foods including rice. There is, however, a knowledge gap with respect to dimethylarsenic concentrations. In this study rice was grown hydroponically and exposed to varying DMA concentrations. High levels of DMA were detrimental to rice plants whereby plants showed symptoms consistent with Straighthead disease, a disease that results in dramatic yield losses.Australian Government ResearchTraining Program ANU OCG Travel Scholarshi

Die Jemandssprache : Plädoyer für eine Deutsche Philologie unter besonderer Berücksichtigung von Heinrich von Morungen, Paul Celan und der "Auslandsgermanistik"

Der Titel „Jemandssprache“ bezieht sich kontrafaktisch auf Paul Celans Gedichtband „Die Niemandsrose“. (...) [In dem ersten Teil seine Aufsatzes bezieht sich Volker Mertens] auf die aktuelle Situation im Fach, in einem zweiten (...) [votiert er] für eine spezifische Gegenstandsbestimmung und einen bestimmten Umgang mit den methodischen Paradigmen, in einem dritten für eine Überwindung der Schwelle zwischen Älterer und Neuerer Literatur, (...), in einem vierten (...) [gibt er] eine vergleichende Interpretation je eines Gedichts von Heinrich von Morungen und von Paul Celan als Beispiel für eine Überschreitung der im Fach institutionalisierten Epochengrenze

Arsenic Species Determination in Biological Tissues by HPLC-ICP-MS and HPLC-HG-ICP-MS

The use of high-pressure liquid chromatography coupled directly or by a hydride generation system to an inductively coupled plasma mass spectrometer for the unambiguous measurement of 13 arsenic species in marine biological extracts is described. The us