Draft genome sequence data of Antarctic Penicillium sp. strain E22, from Deception Island.

Here, we report the draft genome sequence and assembly of the Penicillium sp. strain E22, which was isolated from Antarctic soil of Deception Island, South Shetland Islands close to the Antarctic Peninsula. The genome was sequenced using a 2 # 250 bp paired-end method by Illumina MiSeq 6000. The genome assembly was performed using softwares implemented in the Kbase web service. The phylogenetic tree of strain E22 comparing its internal transcribed spacer (ITS) region with the other Penicillium showed high genetic similarity to Penicillium griseofulvum MN545450 and Penicillium camemberti MT530220. Draf genome of Penicillium sp. strain E22 comprises 33,653 coding sequences, with a high G + C content of 48.32% and a total size of 37,484,944 bp. This draft genome assembly version has been deposited at GenBank under accession JASJUN000000000.

Bioprospecting for Novel Bacterial Sources of Hydrolytic Enzymes and Antimicrobials in the Romanian Littoral Zone of the Black Sea.

Marine microorganisms have evolved a large variety of metabolites and biochemical processes, providing great opportunities for biotechnologies. In the search for new hydrolytic enzymes and antimicrobial compounds with enhanced characteristics, the current study explored the diversity of cultured and uncultured marine bacteria in Black Sea water from two locations along the Romanian coastline. Microbial cell density in the investigated samples varied between 65 and 12.7 × 103 CFU·mL-1. The total bacterial community identified by Illumina sequencing of 16S rRNA gene comprised 185 genera belonging to 46 classes, mainly Gammaproteobacteria, Alphaproteobacteria, Flavobacteriia, and 24 phyla. The 66 bacterial strains isolated on seawater-based culture media belonged to 33 genera and showed variable growth temperatures, growth rates, and salt tolerance. A great fraction of these strains, including Pseudoalteromonas and Flavobacterium species, produced extracellular proteases, lipases, and carbohydrases, while two strains belonging to the genera Aquimarina and Streptomyces exhibited antimicrobial activity against human pathogenic bacteria. This study led to a broader view on the diversity of microbial communities in the Black Sea, and provided new marine strains with hydrolytic and antimicrobial capabilities that may be exploited in industrial and pharmaceutical applications.

Microbiome pattern of Lucilia sericata (Meigen) (Diptera: Calliphoridae) and feeding substrate in the presence of the foodborne pathogen Salmonella enterica.

The microbial diversity and quantitative dynamics during the insect's development stages constitute recently developed putative tools in forensic and medical studies. Meanwhile, little is known on the role of insects in spreading foodborne pathogenic bacteria and on the impact of these pathogens on the overall insects and feeding substrate microbiome composition. Here, we provide the first characterization of the bacterial communities harbored in adult and immature stages of Lucilia sericata, one of the first colonizers of decomposed human remains, in the presence of the foodborne pathogen Salmonella enterica using 16S rRNA Illumina sequencing and qPCR. The pathogen transmission from the wild adults to the second generation was observed, with a 101.25× quantitative increase. The microbial patterns from both insect and liver samples were not influenced by the artificial introduction of this pathogenic foodborne bacteria, being dominated by Firmicutes and Proteobacteria. Overall, our results provided a first detailed overview of the insect and decomposed substrate microbiome in the presence of a human pathogen, advancing the knowledge on the role of microbes as postmortem interval estimators and the transmission of pathogenic bacteria.

Draft Genome Sequence of Flavobacterium sp. Strain PL002, Isolated from Antarctic Porphyra Algae.

Here, we report the draft genome sequence of Flavobacterium sp. strain PL002, isolated from Antarctic Porphyra algae. The 4,299,965-bp genome sequence is assembled into 170 contigs, has 32.92% GC content, and 3,734 predicted genes.

Draft Genome Sequence of Antarctic Psychrotroph Streptomyces fildesensis Strain INACH3013, Isolated from King George Island Soil.

The draft genome sequence of Streptomyces fildesensis strain INACH3013, a psychrotrophic bacterium isolated from Northwest Antarctic soil, was reported. The genome sequence totaling 9,306,785 bp resulted from 122 contigs characterized by a GC content of 70.55%.

First report on antibiotic resistance and antimicrobial activity of bacterial isolates from 13,000-year old cave ice core.

Despite the unique physiology and metabolic pathways of microbiomes from cold environments providing key evolutionary insights and promising leads for discovering new bioactive compounds, cultivable bacteria entrapped in perennial ice from caves remained a largely unexplored life system. In this context, we obtained and characterized bacterial strains from 13,000-years old ice core of Scarisoara Ice Cave, providing first isolates from perennial ice accumulated in caves since Late Glacial, and first culture-based evidences of bacterial resistome and antimicrobial compounds production. The 68 bacterial isolates belonged to 4 phyla, 34 genera and 56 species, with 17 strains representing putative new taxa. The Gram-negative cave bacteria (Proteobacteria and Bacteroidetes) were more resistant to the great majority of antibiotic classes than the Gram-positive ones (Actinobacteria, Firmicutes). More than 50% of the strains exhibited high resistance to 17 classes of antibiotics. Some of the isolates inhibited the growth of clinically important Gram-positive and Gram-negative resistant strains and revealed metabolic features with applicative potential. The current report on bacterial strains from millennia-old cave ice revealed promising candidates for studying the evolution of environmental resistome and for obtaining new active biomolecules for fighting the antibiotics crisis, and valuable cold-active biocatalysts.

An unusual overrepresentation of genetic factors related to iron homeostasis in the genome of the fluorescent Pseudomonas sp. ABC1.

Members of the genus Pseudomonas inhabit diverse environments, such as soil, water, plants and humans. The variability of habitats is reflected in the diversity of the structure and composition of their genomes. This cosmopolitan bacterial genus includes species of biotechnological, medical and environmental importance. In this study, we report on the most relevant genomic characteristics of Pseudomonas sp. strain ABC1, a siderophore-producing fluorescent strain recently isolated from soil. Phylogenomic analyses revealed that this strain corresponds to a novel species forming a sister clade of the recently proposed Pseudomonas kirkiae. The genomic information reveals an overrepresented repertoire of mechanisms to hoard iron when compared to related strains, including a high representation of fecI-fecR family genes related to iron regulation and acquisition. The genome of the Pseudomonas sp. ABC1 contains the genes for non-ribosomal peptide synthetases (NRPSs) of a novel putative Azotobacter-related pyoverdine-type siderophore, a yersiniabactin-type siderophore and an antimicrobial betalactone; the last two are found only in a limited number of Pseudomonas genomes. Strain ABC1 can produce siderophores in a low-cost medium, and the supernatants from cultures of this strain promote plant growth, highlighting their biotechnological potential as a sustainable industrial microorganism.

Heat Shock Response of the Active Microbiome From Perennial Cave Ice.

Ice caves constitute the newly investigated frozen and secluded model habitats for evaluating the resilience of ice-entrapped microbiomes in response to climate changes. This survey identified the total and active prokaryotic and eukaryotic communities from millennium-old ice accumulated in Scarisoara cave (Romania) using Illumina shotgun sequencing of the ribosomal RNA (rRNA) and messenger RNA (mRNA)-based functional analysis of the metatranscriptome. Also, the response of active microbiome to heat shock treatment mimicking the environmental shift during ice melting was evaluated at both the taxonomic and metabolic levels. The putatively active microbial community was dominated by bacterial taxa belonging to Proteobacteria and Bacteroidetes, which are highly resilient to thermal variations, while the scarcely present archaea belonging to Methanomicrobia was majorly affected by heat shock. Among eukaryotes, the fungal rRNA community was shared between the resilient Chytridiomycota and Blastocladiomycota, and the more sensitive Ascomycota and Basidiomycota taxa. A complex microeukaryotic community highly represented by Tardigrada and Rotifera (Metazoa), Ciliophora and Cercozoa (Protozoa), and Chlorophyta (Plantae) was evidenced for the first time in this habitat. This community showed a quick reaction to heat shock, followed by a partial recovery after prolonged incubation at 4°C due to possible predation processes on the prokaryotic cluster. Analysis of mRNA differential gene expression revealed the presence of an active microbiome in the perennial ice from the Scarisoara cave and associated molecular mechanisms for coping with temperature variations by the upregulation of genes involved in enzyme recovery, energy storage, carbon and nitrogen regulation, and cell motility. This first report on the active microbiome embedded in perennial ice from caves and its response to temperature stress provided a glimpse into the impact of glaciers melting and the resilience mechanisms in this habitat, contributing to the knowledge on the functional role of active microbes in frozen environments and their response to climatic changes.

Complete Genome Sequence of Pseudomonas chilensis Strain ABC1, Isolated from Soil.

Here, we report the complete genome sequence of Pseudomonas chilensis strain ABC1, which was isolated from a soil interstitial water sample collected at the University Adolfo Ibañez, Valparaiso, Chile. We assembled PacBio reads into a single closed contig with 209× mean coverage, yielding a 4,035,896-bp sequence with 62% GC content and 3,555 predicted genes.

Evaluation of BOX-PCR and REP-PCR as Molecular Typing Tools for Antarctic Streptomyces.

Molecular studies led to the resurgence of natural products research from genus Streptomyces, already known for their long history and importance for the pharmaceutical industry. However, species belonging to this genus are difficult to identify and the most commonly used techniques, which are based on 16S rRNA sequencing, do not discriminate between related species. In this work, amplification profiles generated from BOX-PCR and REP-PCR of 49 Antarctic soil streptomycetes were compared to evaluate the diversity present in the group and to characterize the bacterial isolates, along with some 16S rRNA amplifications. The BOX-A1R primer exhibit clearer amplification fragments, different from the amplification patterns obtained using the REP 1R and 2R primers. A higher diversity was observed with REP-PCR amplifications, even though a larger number of fragments was obtained with BOX-A1R primer amplifications. There are at least four isolates that showed great similarity (about 90%) in both techniques. In other hand, there are two others that are 90% similar in BOX-PCR, but distant in REP-PCR, showing only 40% of similarity. Results of the combination of BOX-PCR and REP-PCR represent a simple and low-cost method to discriminate between Streptomyces strains. There is no species identification with only the 16S rRNA, most isolates seem to be related to S. globisporus. Further studies added to the obtained results may provide better data to help the characterization of these microorganisms.

Root endophytic Penicillium promotes growth of Antarctic vascular plants by enhancing nitrogen mineralization.

Fungal endophyte associations have been suggested as a possible strategy of Antarctic vascular plants for surviving the extreme environmental conditions of Antarctica. However, the mechanisms by which this occurs are still poorly understood. The role of root fungal endophytes in nitrogen mineralization and nutrient uptake, as well as their impact on the performance of Antarctic plants, were studied. We tested root endophytes, isolated from Colobanthus quitensis and Deschampsia antarctica, for lignocellulolytic enzyme production, nitrogen mineralization, and growth enhancement of their host plants. Penicillium chrysogenum and Penicillium brevicompactum were identified using a molecular approach as the main root endophytes inhabiting C. quitensis and D. antarctica, respectively. Both root endophytes were characterized as psychrophilic fungi displaying amylase, esterase, protease, cellulase, hemicellulase, phosphatase and urease enzymatic activities, mainly at 4 °C. Moreover, the rates and percentages of nitrogen mineralization, as well as the final total biomass, were significantly higher in symbiotic C. quitensis and D. antarctica individuals. Our findings suggest that root endophytes exert a pivotal ecological role based not only to breakdown different nutrient sources but also on accelerating nitrogen mineralization, improving nutrient acquisition, and therefore promoting plant growth in Antarctic terrestrial ecosystems.

Exploring the hydrolytic potential of cultured halophilic bacteria isolated from the Atacama Desert.

Considering that most industrial processes are carried out under harsh physicochemical conditions, which would inactivate enzymes from commonly isolated mesophilic organisms, current studies are geared toward the identification of extremophilic microorganisms producing enzymes resistant to extreme salt concentrations, temperature and pH. Among the extremophiles, halophilic microorganisms are an important source of salt-tolerant enzymes that can be used in varying biotechnological applications. In this context, the aim of the present work was to isolate and identify halophiles producing hydrolases from the Atacama Desert, one of the harshest environments on Earth. Isolates were recovered from halite samples and screened for the presence of seven different hydrolase activities (amylase, caseinase, gelatinase, lipase, pectinase, cellulase and inulinase) using agar plate-based assays. From a total of 23 halophilic bacterial isolates, most showed lipolytic (19 strains) and pectinolytic (11 strains) activities. The molecular identification of eight selected isolates showed a strong similarity to members of the Halomonas and Idiomarina genera. Therefore, the present study represents a preliminary, but essential, step to identify novel biological sources of extremozymes in an environment once thought to be devoid of life.

Total and Potentially Active Bacterial Communities Entrapped in a Late Glacial Through Holocene Ice Core From Scarisoara Ice Cave, Romania.

Our understanding of the icy-habitat microbiome is likely limited by a lack of reliable data on microorganisms inhabiting underground ice that has accumulated inside caves. To characterize how environmental variation impacts cave ice microbial community structure, we determined the composition of total and potentially active bacterial communities along a 13,000-year-old ice core from Scarisoara cave (Romania) through 16S rRNA gene Illumina sequencing. An average of 2,546 prokaryotic gDNA operational taxonomic units (OTUs) and 585 cDNA OTUs were identified across the perennial cave ice block and analyzed in relation to the geochemical composition of ice layers. The total microbial community and the putative active fraction displayed dissimilar taxa profiles. The ice-contained microbiome was dominated by Actinobacteria with a variable representation of Proteobacteria, while the putative active microbial community was equally shared between Proteobacteria and Firmicutes. Accordingly, a major presence of Cryobacterium, Lysinomonas, Pedobacter, and Aeromicrobium phylotypes homologous to psychrotrophic and psychrophilic bacteria from various cold environments were noted in the total community, while the prevalent putative active bacteria belonged to Clostridium, Pseudomonas, Janthinobacterium, Stenotrophomonas, and Massilia genera. Variation in the microbial cell density of ice strata with the dissolved organic carbon (DOC) content and the strong correlation of DOC and silicon concentrations revealed a major impact of depositional processes on microbial abundance throughout the ice block. Post-depositional processes appeared to occur mostly during the 4,000-7,000 years BP interval. A major bacterial composition shift was observed in 4,500-5,000-year-old ice, leading to a high representation of Beta- and Deltaproteobacteria in the potentially active community in response to the increased concentrations of DOC and major chemical elements. Estimated metabolic rates suggested the presence of a viable microbial community within the cave ice block, characterized by a maintenance metabolism in most strata and growth capacity in those ice deposits with high microbial abundance and DOC content. This first survey of microbial distribution in perennial cave ice formed since the Last Glacial period revealed a complex potentially active community, highlighting major shifts in community composition associated with geochemical changes that took place during climatic events that occurred about 5,000 years ago, with putative formation of photosynthetic biofilms.

Investigating the potential use of an Antarctic variant of Janthinobacterium lividum for tackling antimicrobial resistance in a One Health approach.

The aim of this paper is to describe a new variant of Janthinobacterium lividum - ROICE173, isolated from Antarctic snow, and to investigate the antimicrobial effect of the crude bacterial extract against 200 multi-drug resistant (MDR) bacteria of both clinical and environmental origin, displaying various antibiotic resistance patterns. ROICE173 is extremotolerant, grows at high pH (5.5-9.5), in high salinity (3%) and in the presence of different xenobiotic compounds and various antibiotics. The best violacein yield (4.59 ± 0.78 mg·g-1 wet biomass) was obtained at 22 °C, on R2 broth supplemented with 1% glycerol. When the crude extract was tested for antimicrobial activity, a clear bactericidal effect was observed on 79 strains (40%), a bacteriostatic effect on 25 strains (12%) and no effect in the case of 96 strains (48%). A very good inhibitory effect was noticed against numerous MRSA, MSSA, Enterococci, and Enterobacteriaceae isolates. For several environmental E. coli strains, the bactericidal effect was encountered at a violacein concentration below of what was previously reported. A different effect (bacteriostatic vs. bactericidal) was observed in the case of Enterobacteriaceae isolated from raw vs. treated wastewater, suggesting that the wastewater treatment process may influence the susceptibility of MDR bacteria to violacein containing bacterial extracts.

Bacterial and archaeal community structures in perennial cave ice.

Ice entrenched microcosm represents a vast reservoir of novel species and a proxy for past climate reconstitution. Among glacial ecosystems, ice caves represent one of the scarcely investigated frozen habitats. To characterize the microbial diversity of perennial ice from karst ecosystems, Roche 454 sequencing of 16S rRNA gene amplicons from the underground ice block of Scarisoara Ice Cave (Romania) was applied. The temporal distribution of bacterial and archaeal community structures from newly formed, 400, and 900 years old ice layers was surveyed and analyzed in relation with the age and geochemical composition of the ice substrate. The microbial content of cave ice layers varied from 3.3 104 up to 7.5 105 cells mL-1, with 59-78% viability. Pyrosequencing generated 273,102 reads for the five triplicate ice samples, which corresponded to 3,464 operational taxonomic units (OTUs). The distribution of the bacterial phyla in the perennial cave ice varied with age, organic content, and light exposure. Proteobacteria dominated the 1 and 900 years old organic rich ice deposits, while Actinobacteria was mostly found in 900 years old ice strata, and Firmicutes was best represented in 400 years old ice. Cyanobacteria and Chlorobi representatives were identified mainly from the ice block surface samples exposed to sunlight. Archaea was observed only in older ice strata, with a high incidence of Crenarchaeota and Thaumarchaeaota in the 400 years old ice, while Euryarchaeota dominated the 900 years old ice layers, with Methanomicrobia representing the predominant taxa. A large percentage (55.7%) of 16S rRNA gene amplicons corresponded to unidentified OTUs at genus or higher taxa levels, suggesting a greater undiscovered bacterial diversity in this glacial underground habitat. The prokaryotes distribution across the cave ice block revealed the presence of 99 phylotypes specific for different ice layers, in addition to the shared microbial community. Ice geochemistry represented an important factor that explained the microbial taxa distribution in the cave ice block, while the total organic carbon content had a direct impact on the cell density of the ice microcosm. Both bacterial and archaeal community structures appeared to be affected by climate variations during the ice formation, highlighting the cave ice microbiome as a source of putative paleoclimatic biomarkers. This report constitutes the first high-throughput sequencing study of the cave ice microbiome and its distribution across the perennial underground glacier of an alpine ice cave.

Isolation and molecular characterization of Thraustochytrium strain isolated from Antarctic Peninsula and its biotechnological potential in the production of fatty acids

ABSTRACT Thraustochytrids are unicellular protists belonging to the Labyrinthulomycetes class, which are characterized by the presence of a high lipid content that could replace conventional fatty acids. They show a wide geographic distribution, however their diversity in the Antarctic Region is rather scarce. The analysis based on the complete sequence of 18S rRNA gene showed that strain 34-2 belongs to the species Thraustochytrium kinnei, with 99% identity. The total lipid profile shows a wide range of saturated fatty acids with abundance of palmitic acid (16:0), showing a range of 16.1-19.7%. On the other hand, long-chain polyunsaturated fatty acids, mainly docosahexaenoic acid and eicosapentaenoic acid are present in a range of 24-48% and 6.1-9.3%, respectively. All factors analyzed in cells (biomass, carbon consumption and lipid content) changed with variations of culture temperature (10 °C and 25 °C). The growth in glucose at a temperature of 10 °C presented the most favorable conditions to produce omega-3fatty acid. This research provides the identification and characterization of a Thraustochytrids strain, with a total lipid content that presents potential applications in the production of nutritional supplements and as well biofuels.

Isolation and molecular characterization of Thraustochytrium strain isolated from Antarctic Peninsula and its biotechnological potential in the production of fatty acids.

Thraustochytrids are unicellular protists belonging to the Labyrinthulomycetes class, which are characterized by the presence of a high lipid content that could replace conventional fatty acids. They show a wide geographic distribution, however their diversity in the Antarctic Region is rather scarce. The analysis based on the complete sequence of 18S rRNA gene showed that strain 34-2 belongs to the species Thraustochytrium kinnei, with 99% identity. The total lipid profile shows a wide range of saturated fatty acids with abundance of palmitic acid (16:0), showing a range of 16.1-19.7%. On the other hand, long-chain polyunsaturated fatty acids, mainly docosahexaenoic acid and eicosapentaenoic acid are present in a range of 24-48% and 6.1-9.3%, respectively. All factors analyzed in cells (biomass, carbon consumption and lipid content) changed with variations of culture temperature (10°C and 25°C). The growth in glucose at a temperature of 10°C presented the most favorable conditions to produce omega-3fatty acid. This research provides the identification and characterization of a Thraustochytrids strain, with a total lipid content that presents potential applications in the production of nutritional supplements and as well biofuels.

Biological Interactions and Simulated Climate Change Modulates the Ecophysiological Performance of Colobanthus quitensis in the Antarctic Ecosystem.

Most climate and environmental change models predict significant increases in temperature and precipitation by the end of the 21st Century, for which the current functional output of certain symbioses may also be altered. In this context we address the following questions: 1) How the expected changes in abiotic factors (temperature, and water) differentially affect the ecophysiological performance of the plant Colobanthus quitensis? and 2) Will this environmental change indirectly affect C. quitensis photochemical performance and biomass accumulation by modifying its association with fungal endophytes? Plants of C. quitensis from King George Island in the South Shetland archipelago (62°09' S), and Lagotellerie Island in the Antarctic Peninsula (65°53' S) were put under simulated abiotic conditions in growth chambers following predictive models of global climate change (GCC). The indirect effect of GCC on the interaction between C. quitensis and fungal endophytes was assessed in a field experiment carried out in the Antarctica, in which we eliminated endophytes under contemporary conditions and applied experimental watering to simulate increased precipitation input. We measured four proxies of plant performance. First, we found that warming (+W) significantly increased plant performance, however its effect tended to be less than watering (+W) and combined warming and watering (+T°+W). Second, the presence of fungal endophytes improved plant performance, and its effect was significantly decreased under experimental watering. Our results indicate that both biotic and abiotic factors affect ecophysiological performance, and the directions of these influences will change with climate change. Our findings provide valuable information that will help to predict future population spread and evolution through using ecological niche models under different climatic scenarios.

Antibacterial activity of the Antarctic bacterium Janthinobacterium sp: SMN 33. 6 against multi-resistant Gram-negative bacteria

Background The increment of resistant strains to commonly used antibiotics in clinical practices places in evidence the urgent need to search for new compounds with antibacterial activity. The adaptations that Antarctic microorganisms have developed, due to the extreme environment that they inhabit, promote them as a potential new source of active compounds for the control of microorganisms causing infections associated with health care. The aim of this study was to evaluate the antibacterial activity of an ethanol extract of the Antarctic bacterium Janthinobacterium sp., strain SMN 33.6, against nosocomial multi-resistant Gram-negative bacteria. Results Inhibitory activity against human Gram-negative bacterial pathogens, with concentrations that varied between 0.5 and 16 µg ml- 1, was demonstrated. Conclusions The ethanolic extract of Janthinobacterium sp. SMN 33.6 possesses antibacterial activity against a chromosomal AmpC beta-lactamase-producing strain of Serratia marcescens, an extended-spectrum beta-lactamase-producing Escherichia coli and also against carbapenemase-producing strains of Acinetobacter baumannii and Pseudomonas aeruginosa. This becomes a potential and interesting biotechnological tool for the control of bacteria with multi-resistance to commonly used antibiotics.

Novel lineages of Prochlorococcus thrive within the oxygen minimum zone of the eastern tropical South Pacific.

The eastern tropical Pacific Ocean holds two of the main oceanic oxygen minimum zones of the global ocean. The presence of an oxygen-depleted layer at intermediate depths, which also impinges on the seafloor and in some cases the euphotic zone, plays a significant role in structuring both pelagic and benthic communities, and also in the vertical partitioning of microbial assemblages. Here, we assessed the genetic diversity and distribution of natural populations of the cyanobacteria Prochlorococcus and Synechococcus within oxic and suboxic waters of the eastern tropical Pacific using cloning and sequencing, and terminal restriction fragment length polymorphism (T-RFLP) analyses applied to the 16S-23S rRNA internal transcribed spacer region. With the T-RFLP approach we could discriminate 19 cyanobacterial clades, of which 18 were present in the study region. Synechococcus was more abundant in the surface oxic waters of the eastern South Pacific, while Prochlorococcus dominated the subsurface low-oxygen waters. Two of the dominant clades in the oxygen-deficient waters belong to novel and yet uncultivated lineages of low-light adapted Prochlorococcus.