Prokaryotic communities and operating metabolisms in the surface and the permafrost of Deception Island (Antarctica)

Abstract

In this study we examined the microbial community composition and operating metabolisms on the surface and in the permafrost of Deception Island, (Antarctica) with an on site antibody microarray biosensor. Samples (down to a depth of 4.2 m) were analysed with LDChip300 (Life Detector Chip), an immunosensor containing more than 300 antibodies targeted to bacterial and archaeal antigens. The immunograms showed positive antigen-antibody reactions in all surface samples (lichens, pyroclasts) and the top layer of the permafrost. The results indicated the presence of exopolysaccharides, bacteria belonging to the Alpha-, Delta- and Gammaproteobacteria, Bacteroidetes, Gram-positive Actinobacteria and Firmicutes, as well as archaeal species, most probably Methanobacterium spp. Positive reactions with antibodies to proteins and peptides revealed the presence of nitrogen fixation (NifHD, GlnB, HscA), methanogenic (McrB), iron homeostasis and iron scavenging (ferritins and DPS proteins) proteins, as well as ABC transporters, which indicated that these processes were operating at the time of sampling. These results were validated with other molecular ecology techniques such as oligonucleotide microarrays, 16S bacterial rRNA gene sequence analysis, aerobic viable counts and microscopy. Molecular ecology results showed a differentiated pattern along the depth of the drill, being the top active layer the most diverse, with Acidobacteria, Actinobacteria, Proteobacteria, Bacteroidetes and the phototrophs Cyanobacteria and Chloroflexi as dominant groups. Actinobacteria and Firmicutes were dominant in depths from 0.5 to 2 m, and Betaproteobacteria from 3 to 4.2 m. The geochemical analysis revealed the presence of low molecular weight organic acids (acetate, formate) which could be used by microorganisms as energy sources for sulfate, nitrate and metal reduction under anaerobic conditions.

CYANOCHIP: An Antibody Microarray for High-Taxonomical-Resolution Cyanobacterial Monitoring

“…Purified antibodies were printed in a triplicate spot pattern on epoxy-activated glass slides as previously reported. 17,20 Preparation of Antigens for Sandwich Microarray Immunoassays (SMIs). Cyanobacterial isolates obtained from the cyanobacterial collection of the research group of Pilar Mateo and Antonio Quesada at the Universidad Autońoma de Madrid as well as natural samples obtained from a range of ecosystems were sonicated for 5 cycles of 30 s with a 30 s pause on ice using a hand-held sonicator (Dr. Hielscher 50 W DRH-UP50H sonicator, Hielscher Ultrasonics, Berlin, Germany) to disaggregate the colonies and used as antigens for rabbit immunization (see above) and for taxonomical chip validation.…”

Ecology and biogeochemistry of cyanobacteria in soils, permafrost, aquatic and cryptic polar habitats

“…Cyanobacterial taxa were present in all core samples, but could not be cultivated. In a 4.2 m permafrost core from Deception Island, the microbial community showed a well-stratified distribution (Blanco et al 2012), with cyanobacteria (Nostoc sp.) only present to a depth of 1.6-2.0 m. Cyanobacteria can ac-tively move in response to wetting or drying events by migrating towards or retreating from the soil surface (Garcia-Pichel and Pringault 2001).…”

A lander mission to probe subglacial water on Saturn׳s moon Enceladus for life

“…Aside from the goal of in situ probing of an active aquiferous fracture for biosignatures, the resulting objective is the detection of extant life that potentially incorporates the previously mentioned MCTs, namely molecular replication, cellularization and metabolic networks. Several of the proposed instruments are routinely used in the (biological) exploration of extreme habitats on Earth such as deep-sea hydrothermal vents and sediment, subglacial lakes, and the continental subsurface [35][36][37][38][39][40]. Due to volume constraints, however, only a limited number of instruments would be able to be integrated into an ice melting probe.…”