Microbial degradation of dimethylsulphide and related C1-sulphur compounds: organisms and pathways controlling fluxes of sulphur in the biosphere

Dimethylsulphide (DMS) plays a major role in the global sulphur cycle. It has important implications for atmospheric chemistry, climate regulation, and sulphur transport from the marine to the atmospheric and terrestrial environments. In addition, DMS acts as an info-chemical for a wide range of organisms ranging from micro-organisms to mammals. Micro-organisms that cycle DMS are widely distributed in a range of environments, for instance, oxic and anoxic marine, freshwater and terrestrial habitats. Despite the importance of DMS that has been unearthed by many studies since the early 1970s, the understanding of the biochemistry, genetics, and ecology of DMS-degrading micro-organisms is still limited. This review examines current knowledge on the microbial cycling of DMS and points out areas for future research that should shed more light on the role of organisms degrading DMS and related compounds in the biosphere

Victrices scientiarum of 1904: Who were the first women elected as Fellows of the Linnean Society of London?

Published within The Linnean Special Issue No. 10 "‘The Door Was Opened’ Pioneering Women at the Linnean Society of London and Their Continuing Legacy" Compiled and edited by Gina Douglas Hon FLS and Leonie Berwic

Substrate-specific clades of active marine methylotrophs associated with a phytoplankton bloom in a temperate coastal environment

Marine microorganisms that consume one-carbon (C1) compounds are poorly described, despite their impact on global climate via an influence on aquatic and atmospheric chemistry. This study investigated marine bacterial communities involved in the metabolism of C1 compounds. These communities were of relevance to surface seawater and atmospheric chemistry in the context of a bloom that was dominated by phytoplankton known to produce dimethylsulfoniopropionate. In addition to using 16S rRNA gene fingerprinting and clone libraries to characterize samples taken from a bloom transect in July 2006, seawater samples from the phytoplankton bloom were incubated with 13C-labeled methanol, monomethylamine, dimethylamine, methyl bromide, and dimethyl sulfide to identify microbial populations involved in the turnover of C1 compounds, using DNA stable isotope probing. The [13C]DNA samples from a single time point were characterized and compared using denaturing gradient gel electrophoresis (DGGE), fingerprint cluster analysis, and 16S rRNA gene clone library analysis. Bacterial community DGGE fingerprints from 13C-labeled DNA were distinct from those obtained with the DNA of the nonlabeled community DNA and suggested some overlap in substrate utilization between active methylotroph populations growing on different C1 substrates. Active methylotrophs were affiliated with Methylophaga spp. and several clades of undescribed Gammaproteobacteria that utilized methanol, methylamines (both monomethylamine and dimethylamine), and dimethyl sulfide. rRNA gene sequences corresponding to populations assimilating 13C-labeled methyl bromide and other substrates were associated with members of the Alphaproteobacteria (e.g., the family Rhodobacteraceae), the Cytophaga-Flexibacter-Bacteroides group, and unknown taxa. This study expands the known diversity of marine methylotrophs in surface seawater and provides a comprehensive data set for focused cultivation and metagenomic analyses in the future

Microbiology survey shows authors have most to gain from peer review

In the week that an international team of publishers, science communicators and other scholarly organisations launch the second international Peer Review Week, the preliminary findings from our new survey reveal that authors gain more from peer review than the people who do the actual review

Reclassification of Thiomicrospira hydrogeniphila (Watsuji et al. 2016) to Thiomicrorhabdus hydrogenophila comb. nov., with emended description of Thiomicrorhabdus (Boden et al., 2017)

The genus Thiomicrorhabdus (Tmr) in the Piskirickettsiaceae in the Thiotrichales of the Gammaproteobacteria contains four species of sulfur-oxidising obligate chemolithoautotroph with validly published names, all previously classified as Thiomicrospira (Tms) species. Here we demonstrate that Thiomicrospira hydrogeniphila , a recently published hydrogen-utilising chemolithoautotroph closely related to Thiomicrorhabdus frisia (type species of Thiomicrorhabdus ) should be classified as a member of the genus Thiomicrorhabdus and not Thiomicrospira , as Thiomicrorhabdus hydrogeniphila comb. nov., on the basis of comparative physiology and morphology as well as 16S rRNA (rrs) gene identity of Tms. hydrogeniphila MAS2T being closer to that of Tmr. frisia JB-A2T (99.1 %) than to Tms. pelophila DSM 1534T (90.5 %) or Hydrogenovibrio marinus MH-110T (94.1 %), and on the basis of the topology of 16S rRNA gene maximum likelihood trees, which clearly place Tms. hydrogeniphila within the genus Thiomicrorhabdus . It was also noted that thiosulfate-grown Thiomicrorhabdus spp. can be distinguished from Thiomicrospira spp. or Hydrogenovibrio spp. on the basis of the 3 dominant fatty acids (C16 : 1, C18 : 1 and C16 : 0), and from other Thiomicrorhabdus spp. on the basis of the fourth dominant fatty acid, which varies between the species of this genus – which could provide a useful diagnostic method. We provide an emended description of Thiomicrorhabdus (Boden R, Scott KM, Williams J, Russel S, Antonen K et al. Int J Syst Evol Microbiol 2017;67:1140–1151) to take into account the properties of Thiomicrorhabdus hydrogeniphila comb. nov.c

The COVID-19 Pandemic and Global Food Security

We present scientific perspectives on the impact of the COVID-19 pandemic and global food security. International organizations and current evidence based on other respiratory viruses suggests COVID-19 is not a food safety issue, i.e., there is no evidence associating food or food packaging with the transmission of the virus causing COVID-19 (SARS-CoV-2), yet an abundance of precaution for this exposure route seems appropriate. The pandemic, however, has had a dramatic impact on the food system, with direct and indirect consequences on lives and livelihoods of people, plants, and animals. Given the complexity of the system at risk, it is likely that some of these consequences are still to emerge over time. To date, the direct and indirect consequences of the pandemic have been substantial including restrictions on agricultural workers, planting, current and future harvests; shifts in agricultural livelihoods and food availability; food safety; plant and animal health and animal welfare; human nutrition and health; along with changes in public policies. All aspects are crucial to food security that would require “One Health” approaches as the concept may be able to manage risks in a cost-effective way with cross-sectoral, coordinated investments in human, environmental, and animal health. Like climate change, the effects of the COVID-19 pandemic will be most acutely felt by the poorest and most vulnerable countries and communities. Ultimately, to prepare for future outbreaks or threats to food systems, we must take into account the Sustainable Development Goals of the United Nations and a “Planetary Health” perspective

Identificaction and quantificationof proteins from Methylophaga Thiooxidans and Methylocella Silvestris using label-free LC/MS

Comunicaciones a congreso

Evaluation of the genus Thiothrix Winogradsky 1888 (Approved Lists 1980) emend. Aruga et al. 2002: reclassification of Thiothrix disciformis to Thiolinea disciformis gen. nov., comb. nov., and of Thiothrix flexilis to Thiofilum flexile gen. nov., comb nov., with emended description of Thiothrix.

Thiothrix is the type genus of the Thiotrichaceae in the Thiotrichales of the 21 Gammaproteobacteria, comprising nine species of sulfur-oxidising filamentous Bacteria, 22 which are variously autotrophic, heterotrophic or have mixed metabolic modes. Within the 23 genus, 4 species show 16S rRNA gene identities lower the Yarza threshold for the rank of 24 genus (94.5 %) – Thiothrix disciformis, Thiothrix flexilis, Thiothrix defluvii and Thiothrix 25 eikelboomii – as they show no affiliation to extant genera, a polyphasic study was undertaken 26 including biochemical, physiological and genomic properties and phylogeny based on the 27 16S rRNA gene (rrs), recombination protein A (RecA), polynucleotide nucleotidyltransferase 28 (Pnp), translation initiation factor IF-2 (InfB), glyceraldehyde-3-phosphate dehydrogenase 29 (GapA), glutaminyl-tRNA synthetase (GlnS), elongation factor EF-G (FusA) and 30 concatamers of 53 ribosomal proteins encoded by rps, rpl and rpm operons, all of which 31 support the reclassification of these species. We thus propose Thiolinea gen. nov. and 32 Thiofilum gen. nov. for which the type species are Thiolinea disciformis gen. nov., comb. 33 nov. and Thiofilum flexile gen. nov., comb. nov. We also propose that these genera are each 34 circumscribed into novel families Thiolinaceae fam. nov. and Thiofilaceae fam. nov., and 35 that Leucothrix and Cocleimonas are circumscribed into Leucotrichaceae fam. nov. and 36 provide emended descriptions of Thiothrix and Thiotrichaceae

Metabolism of dimethylsulfide in the bacteria

Dimethylsulfide (DMS) is a volatile organosulfur compound which has been implicated as playing key roles in climate control and in the biogeochemical cycling of sulfur. Metabolism of DMS by Bacteria has been previously identified as an important sink of DMS in soils and in the marine environment; however, relatively little is known about the physiology or biochemistry of Bacteria that metabolism DMS. The key enzyme of DMS oxidation in Hyphomicrobium spp. – DMS monooxygenase - has been purified and characterised from H. sulfonivorans. It has been shown to be a two-componant monooxygenase, related to bacterial luciferase, comprising two subunits – an FMNH2-dependent DMS monooxygenase (DmoA) and an NADHdependent FMN oxidoreductase (DmoB). For DMS, DMS monooxygenase from H. sulfonivorans has a Vmax of 1250 nmol DMS oxidised min-1 (mg protein)-1 and a kM of 16.5μM, corresponding to a kCAT of 5.2s-1. DMS oxidation in terms of acting as a sole-carbon source and as a supplementary energy source has been demonstrated in methylotrophic and heterotrophic bacteria. Chemolithoheterotrophic growth in which DMS carbon is assimilated to biomass whilst DMS sulfur is oxidised to tetrathionate with a net energy gain has been demonstrated in “M. thiooxidans”. Both “internal” and “external” chemolithoheterotrophy has been observed in “M. thiooxidans”, with endogenous and exogenous thiosulfate being oxidised to tetrathionate with a net energy gain. As far as can be found from the literature, this is the first recorded production of a polythionate from an organosulfur compound, as such, representing a potential new step in the biogeochemical sulfur cycle. Stable-isotope probing with [13C2]-DMS has been performed for the first time and has confirmed Methylophaga spp. as dominant DMS-oxidising Bacteria in the marine environment. The oxidation of marine thiosulfate to tetrathionate has been demonstrating during a phytoplankton bloom, indicating that chemolithoheterotrophic Bacteria are active during the bloom. Preliminary analyses have been carried out on the genome sequence of “Methylophaga thiooxidans” and the genes encoding the major enzymes of formaldehyde assimilation via the KDPG aldolase variant RuMP pathway have been identified. Genes encoding key enzymes involved in the dissimilation of methanol and methylated amines have been indentified, in addition to those involved in nitrogen uptake from ammonia, nitrate, nitrite and urea. Chemoorganoheterotrophic growth, coupling the oxidation of DMS to DMSO with ATP formation, has been demonstrated in Sagittula stellata E-37T, though the enzyme(s) responsible for this oxidation remain unclear