Latitude and chlorophyll a density drive the distribution of carbohydrate-active enzymes in the planktonic microbial fraction of the epipelagic zone.

Microbes drive the majority of the global carbon cycle. The effect of environmental conditions on selecting microbial functional diversity is well established, and recent studies have revealed the effects of geographic distances on selecting the functional components of marine microbial communities. Our study is the first attempt at establishing the effects of environmental factors on driving the marine carbohydrate-active enzyme (CAZyme) distribution. We characterized the diversity of CAZyme genes and investigated the correlations between their distributions and biogeographic parameters (latitude, longitude, distance from the equator, site depth, water depth, chlorophyll density, salinity and temperature). Therefore, we accessed a subset of surface water samples (38 metagenomes) from the Global Ocean Sampling project. Only chlorophyll and latitude altered the distribution patterns of CAZymes, revealing the existence of two latitudinal gradients (positive and negative) of marine CAZyme abundance. Considering the importance of carbohydrates in microbial life, characterization of the spatial patterns of the genetic repertoire involved in carbohydrate metabolism represents an important step in improving our understanding of the metabolic strategies associated with the microbial marine carbon cycle and their effects on the productivity of marine ecosystems.

The skin microbiome of the common thresher shark (Alopias vulpinus) has low taxonomic and gene function ß-diversity.

The health of sharks, like all organisms, is linked to their microbiome. At the skin interface, sharks have dermal denticles that protrude above the mucus, which may affect the types of microbes that occur here. We characterized the microbiome from the skin of the common thresher shark (Alopias vulpinus) to investigate the structure and composition of the skin microbiome. On average 618 812 (80.9% ± S.D. 0.44%) reads per metagenomic library contained open reading frames; of those, between 7.6% and 12.8% matched known protein sequences. Genera distinguishing the A. vulpinus microbiome from the water column included, Pseudoalteromonas (12.8% ± 4.7 of sequences), Erythrobacter (5. 3% ± 0.5) and Idiomarina (4.2% ± 1.2) and distinguishing gene pathways included, cobalt, zinc and cadmium resistance (2.2% ± 0.1); iron acquisition (1.2% ± 0.1) and ton/tol transport (1.3% ± 0.08). Taxonomic community overlap (100 - dissimilarity index) was greater in the skin microbiome (77.6), relative to the water column microbiome (70.6) and a reference host-associated microbiome (algae: 71.5). We conclude the A. vulpinus skin microbiome is influenced by filtering processes, including biochemical and biophysical components of the shark skin and result in a structured microbiome.

Microbes, metagenomes and marine mammals: enabling the next generation of scientist to enter the genomic era.

BACKGROUND: The revolution in DNA sequencing technology continues unabated, and is affecting all aspects of the biological and medical sciences. The training and recruitment of the next generation of researchers who are able to use and exploit the new technology is severely lacking and potentially negatively influencing research and development efforts to advance genome biology. Here we present a cross-disciplinary course that provides undergraduate students with practical experience in running a next generation sequencing instrument through to the analysis and annotation of the generated DNA sequences. RESULTS: Many labs across world are installing next generation sequencing technology and we show that the undergraduate students produce quality sequence data and were excited to participate in cutting edge research. The students conducted the work flow from DNA extraction, library preparation, running the sequencing instrument, to the extraction and analysis of the data. They sequenced microbes, metagenomes, and a marine mammal, the Californian sea lion, Zalophus californianus. The students met sequencing quality controls, had no detectable contamination in the targeted DNA sequences, provided publication quality data, and became part of an international collaboration to investigate carcinomas in carnivores. CONCLUSIONS: Students learned important skills for their future education and career opportunities, and a perceived increase in students' ability to conduct independent scientific research was measured. DNA sequencing is rapidly expanding in the life sciences. Teaching undergraduates to use the latest technology to sequence genomic DNA ensures they are ready to meet the challenges of the genomic era and allows them to participate in annotating the tree of life.

Metagenomic insights into anaerobic metabolism along an Arctic peat soil profile.

A metagenomic analysis was performed on a soil profile from a wet tundra site in northern Alaska. The goal was to link existing biogeochemical knowledge of the system with the organisms and genes responsible for the relevant metabolic pathways. We specifically investigated how the importance of iron (Fe) oxides and humic substances (HS) as terminal electron acceptors in this ecosystem is expressed genetically, and how respiratory and fermentative processes varied with soil depth into the active layer and into the upper permafrost. Overall, the metagenomes reflected a microbial community enriched in a diverse range of anaerobic pathways, with a preponderance of known Fe reducing species at all depths in the profile. The abundance of sequences associated with anaerobic metabolic processes generally increased with depth, while aerobic cytochrome c oxidases decreased. Methanogenesis genes and methanogen genomes followed the pattern of CH4 fluxes: they increased steeply with depth into the active layer, but declined somewhat over the transition zone between the lower active layer and the upper permafrost. The latter was relatively enriched in fermentative and anaerobic respiratory pathways. A survey of decaheme cytochromes (MtrA, MtrC and their homologs) revealed that this is a promising approach to identifying potential reducers of Fe(III) or HS, and indicated a possible role for Acidobacteria as Fe reducers in these soils. Methanogens appear to coexist in the same layers, though in lower abundance, with Fe reducing bacteria and other potential competitors, including acetogens. These observations provide a rich set of hypotheses for further targeted study.