Microbial assemblages and associated biogeochemical processes in Lake Bonney, a permanently ice-covered lake in the McMurdo Dry Valleys, Antarctica.

BACKGROUND: Lake Bonney, which is divided into a west lobe (WLB) and an east lobe (ELB), is a perennially ice-covered lake located in the McMurdo Dry Valleys of Antarctica. Despite previous reports on the microbial community dynamics of ice-covered lakes in this region, there is a paucity of information on the relationship between microbial genomic diversity and associated nutrient cycling. Here, we applied gene- and genome-centric approaches to investigate the microbial ecology and reconstruct microbial metabolic potential along the depth gradient in Lake Bonney. RESULTS: Lake Bonney is strongly chemically stratified with three distinct redox zones, yielding different microbial niches. Our genome enabled approach revealed that in the sunlit and relatively freshwater epilimnion, oxygenic photosynthetic production by the cyanobacterium Pseudanabaena and a diversity of protists and microalgae may provide new organic carbon to the environment. CO-oxidizing bacteria, such as Acidimicrobiales, Nanopelagicales, and Burkholderiaceae were also prominent in the epilimnion and their ability to oxidize carbon monoxide to carbon dioxide may serve as a supplementary energy conservation strategy. In the more saline metalimnion of ELB, an accumulation of inorganic nitrogen and phosphorus supports photosynthesis despite relatively low light levels. Conversely, in WLB the release of organic rich subglacial discharge from Taylor Glacier into WLB would be implicated in the possible high abundance of heterotrophs supported by increased potential for glycolysis, beta-oxidation, and glycoside hydrolase and may contribute to the growth of iron reducers in the dark and extremely saline hypolimnion of WLB. The suboxic and subzero temperature zones beneath the metalimnia in both lobes supported microorganisms capable of utilizing reduced nitrogens and sulfurs as electron donors. Heterotrophs, including nitrate reducing sulfur oxidizing bacteria, such as Acidimicrobiales (MAG72) and Salinisphaeraceae (MAG109), and denitrifying bacteria, such as Gracilimonas (MAG7), Acidimicrobiales (MAG72) and Salinisphaeraceae (MAG109), dominated the hypolimnion of WLB, whereas the environmental harshness of the hypolimnion of ELB was supported by the relatively low in metabolic potential, as well as the abundance of halophile Halomonas and endospore-forming Virgibacillus. CONCLUSIONS: The vertical distribution of microbially driven C, N and S cycling genes/pathways in Lake Bonney reveals the importance of geochemical gradients to microbial diversity and biogeochemical cycles with the vertical water column.

CO2 Hydrogenation on Carbides Formed in situ on Carbon-Supported Iron-Based Catalysts in High-Density Supercritical Medium.

CO2 conversion via hydrogenation on iron-based catalysts on non-carbon supports produces mainly CO or methane by the Sabatier reaction, while the formation of C2+ hydrocarbons is of greatest interest. CxHy production from CO2 may be considered as a two-step process with the initial formation of carbon monoxide by the reverse water gas shift reaction followed by the Fischer-Tropsch synthesis (FTS). In the present work CO2 hydrogenation over iron-based catalysts (Fe, FeCr, FeK) deposited on a carbon carrier has been studied. The catalyst structure has been investigated by XRD, TEM, XPS, Mössbauer spectroscopy and in situ magnetometry. Spinel-type oxide phases (magnetite Fe3O4; maggemite γ-Fe2O3, and, in the case of FeCr/C catalyst, iron chromite Fe1+xCr2-xO4) are formed on the catalysts, and they contribute exclusively to the CO production. Iron carbides, active in FTS, are formed on Fe- and FeK-catalysts during pre-activation in reducing environment and then during the reaction. The reaction over the 20Fe1K/C catalyst in supercritical high-density CO2/H2 substrate (400°C, 8.5 MPa) leads to 72% selectivity for C1-C12+ hydrocarbons (alkanes and alkenes). Under the same conditions, iron carbides do not form on the FeCr/C catalysts, and CO2 hydrogenation results in the CO formation with the selectivity of 90-100%.

Environmental Adaptation of Psychrophilic Bacteria Subtercola spp. Isolated from Various Cryospheric Habitats.

Subtercola boreus K300T is a novel psychrophilic strain that was isolated from permanently cold groundwater in Finland and has also been found in several places in Antarctica including lake, soil, and rocks. We performed genomic and transcriptomic analyses of 5 strains from Antarctica and a type strain to understand their adaptation to different environments. Interestingly, the isolates from rocks showed a low growth rate and smaller genome size than strains from the other isolation sources (lake, soil, and groundwater). Based on these habitat-dependent characteristics, the strains could be classified into two ecotypes, which showed differences in energy production, signal transduction, and transcription in the clusters of orthologous groups of proteins (COGs) functional category. In addition, expression pattern changes revealed differences in metabolic processes, including uric acid metabolism, DNA repair, major facilitator superfamily (MFS) transporters, and xylose degradation, depending on the nutritional status of their habitats. These findings provide crucial insights into the environmental adaptation of bacteria, highlighting genetic diversity and regulatory mechanisms that enable them to thrive in the cryosphere.

Glaciers as microbial habitats: current knowledge and implication.

Glaciers, formed from the gradual accumulation of snow, can be continuous records representing past environments and recognized as a time capsule of our planetary evolution. Due to extremely harsh conditions, glacial ice has long been considered an uninhabitable ecosystem for microorganisms to sustain their life. However, recent developments in microbiological analysis techniques revealed the presence of unexpectedly diverse microbial strains. Glacial microorganisms could also provide valuable information, including not only biological diversity and structure but also molecular systematics, metabolic profiles, and evolutionary changes from the past climate and ecosystem. However, there are several obstacles in investigating the glacier environment, such as low regional accessibility, technical difficulties of ice coring, potential contamination during the sampling process, and low microbial biomass. This review aims to summarize recent knowledge on decontamination methods, biomass, diversity based on culture-dependent and -independent methods, application of biological proxies, greenhouse gas production and adaptive strategies in glaciers from various regions and to imply further directions for a comprehensive understanding of habitatility in an icy world including outer of our planet.

Draft Genome Sequence of the Chitin-Degrading Psychrotolerant Bacterium Pedobacter jejuensis TN23, Isolated from Antarctic Soil.

Pedobacter jejuensis TN23 was isolated from soil from Terra Nova Bay, Victoria Land, Antarctica. The assembled draft genome size is 4,795,808 bp, and it contains a total of 4,095 genes with 3,970 coding sequences, including genes putatively involved in the degradation of chitin.

Draft Genome Sequence of the Psychrotolerant Bacterium Methylobacterium sp. Strain BTF04, Isolated from Freshwater in Antarctica.

Methylobacterium sp. strain BTF04, a pink-pigmented psychrotolerant bacterium, was isolated from freshwater on Barton Peninsula, King George Island, Antarctica. Here, we report the assembled draft genome sequence of Methylobacterium sp. strain BTF04.

Draft Genome Sequence of Arthrobacter oryzae TNBS02, a Bacterium Containing Heavy Metal Resistance Genes, Isolated from Soil of Antarctica.

Arthrobacter oryzae TNBS02 was isolated from soil at Terra Nova Bay of Victoria Land, Antarctica. The genome consists of a chromosome with 4,248,670 bp which contains a total of 3,994 genes. It was identified that this strain has many heavy metal resistance genes similar to other Arthrobacter strains isolated from contaminated environments.

The latitudinal gradient in rock-inhabiting bacterial community compositions in Victoria Land, Antarctica.

The harsh conditions in Victoria Land, Antarctica have formed a simple ecosystem dominated by microbes that use rocks as shelters to avoid environmental stressors. The area is composed of basement rocks that illustrate the history of complex deformation, thus it is highly valuable not only in perspectives of geology but also in biological aspects. Because this region is inhospitable to higher-level organisms and receives least external influences, it can be an ideal environment to investigate the relationship between rock-inhabiting bacterial communities and environmental factors. In such conditions, inorganics dissolved from minerals can be considered as key factors influencing rock-inhabiting bacterial communities. Thus, the present study attempted to explore rock-inhabiting bacterial communities throughout Victoria Land, to identify environmental parameters that are more influential on bacterial community compositions, and to investigate latitudinal gradients in environmental parameters and rock-inhabiting bacterial communities. The results suggested that (i) rock-inhabiting bacterial communities in Victoria Land predominately consisted of either Actinobacteria or Proteobacteria; (ii) latitudinal gradients in rock-inhabiting bacterial community compositions and some environmental parameters were observed; (iii) latitude, pH, nitrate, and sulfate significantly correlated with the dominant phyla; and (iv) the Classification and Regression Tree (CART) analysis demonstrated that latitude, pH, and sulfate concentrations could explain the dominant phylum with 89% accuracy. These findings can provide important insight into the link between environmental factors and rock-inhabiting bacterial community compositions in conditions with extremely cold temperatures and high levels of radiation, which could also be of interest in astrobiology.

Effects of Obesity Management Program Provided by Occupational Health Nurse in Worksite.

This study was conducted on 60 male adult technicians in the worksite to examine the impact of the obesity management program on their eating habits, exercise self-efficacy, quality of life, and body components. This was a nonrandomized pretest and posttest intervention study. The obesity management program was applied for 16 weeks on diet education, exercise, and counseling provided by the occupational health nurse in the worksite. The questionnaire for measure included the general characteristics, eating habits, exercise self-efficacy, and quality of life. Body components were measured by using the InBody 720 device. The participants who received the obesity management program showed better eating habits, a higher level of exercise self-efficacy, a higher level of quality of life, lower levels of body weight and body mass index (BMI), a smaller waist and hip circumference, and a higher level of muscle mass as compared with the preapplication.

Comparisons of Health Promoting Behavior, Depression, and Life Satisfaction Between Older Adults in Rural Areas in South Korea Living in Group Homes and at Home.

BACKGROUND: In South Korea, population aging is advancing at a more rapid rate in rural areas than urban areas, leading to a particularly high percentage of rural-dwelling older adults. PURPOSE: The aim of this study was to examine and compare health promoting behaviors, depression, and life satisfaction between rural-dwelling older adults who live, respectively, in group homes and at home. METHODS: A cross-sectional descriptive study design was employed. Study participants included 160 older adults aged 65 years and older who were living in group homes (n = 80) and at home (n = 80) in Gyeonggi province, South Korea. The Health Promotion Lifestyle Profile-II was used to examine health promoting behaviors, the Korean Geriatric Depression Screening Scale was used to examine depression, and the Life Satisfaction Index was used to examine life satisfaction. Data were analyzed using SPSS Version 21.0. RESULTS: The data showed significant differences between the two groups in terms of health promoting behaviors (t = -9.035, p < .001), depression (t = 20.861, p < .001), and life satisfaction (t = -12.153, p < .001). CONCLUSIONS/IMPLICATIONS FOR PRACTICE: The mean scores for health promotion behaviors and life satisfaction were higher, and the mean score for depression was lower in the group-home group than the at-home group. The findings from this study may be employed as basic data for establishing residence-appropriate nursing intervention protocols for older adults living in rural areas.

[18F]FET PET is a useful tool for treatment evaluation and prognosis prediction of anti-angiogenic drug in an orthotopic glioblastoma mouse model.

O-2-18F-fluoroethyl-l-tyrosine ([18F]FET) has been widely used for glioblastomas (GBM) in clinical practice, although evaluation of its applicability in non-clinical research is still lacking. The objective of this study was to examine the value of [18F]FET for treatment evaluation and prognosis prediction of anti-angiogenic drug in an orthotopic mouse model of GBM. Human U87MG cells were implanted into nude mice and then bevacizumab, a representative anti-angiogenic drug, was administered. We monitored the effect of anti-angiogenic agents using multiple imaging modalities, including bioluminescence imaging (BLI), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET/CT). Among these imaging methods analyzed, only [18F]FET uptake showed a statistically significant decrease in the treatment group compared to the control group (P=0.02 and P=0.03 at 5 and 20 mg/kg, respectively). This indicates that [18F]FET PET is a sensitive method to monitor the response of GBM bearing mice to anti-angiogenic drug. Moreover, [18F]FET uptake was confirmed to be a significant parameter for predicting the prognosis of anti-angiogenic drug (P=0.041 and P=0.007, on Days 7 and 12, respectively, on Pearson's correlation; P=0.048 and P=0.030, on Days 7 and 12, respectively, on Cox regression analysis). However, results of BLI or MRI were not significantly associated with survival time. In conclusion, this study suggests that [18F]FET PET imaging is a pertinent imaging modality for sensitive monitoring and accurate prediction of treatment response to anti-angiogenic agents in an orthotopic model of GBM.

Complete Genome Sequence of a Psychrotolerant Denitrifying Bacterium, Janthinobacterium svalbardensis PAMC 27463.

We report here the complete genome sequence of Janthinobacterium svalbardensis PAMC 27463 isolated from a freshwater lake on Barton Peninsula on King George Island, Antarctica. The genome consists of a chromosome with 6,274,078 bp which contains 5,585 genes, including 121 RNA genes.

Life experiences of elderly people with suicide ideation at the long-term care hospitals in South Korea.

OBJECTIVE: To understand the life experiences of elderly people who are living in long-term care hospitals and are afflicted with suicide ideation. METHODS: A phenomenological qualitative methodology based on Colaizzi's method was used for the study. Participants included 9 elderly people who are 65 years old or older with suicidal ideas and were admitted in any of the 3 long-term care hospitals in D City, Gyeonggi-do, South Korea. Data were collected from July to December 2014. RESULTS: Seven categories, 15 theme categories, 30 themes, and 88 significant items were identified as parts of their life experiences. The 7 categories were identified as "being a slave to one's disease", "sadness as a result of being far away from one's family", "vain care and consolation for me", "continued life in a hospital, which feels like living abroad", "plunging life", "moving toward the end of life", and "sad relief from death". CONCLUSION: The findings from this study provide a deep understanding of the lives of elderly people who were staying in long-term care hospitals, and these will help improve their quality of life. Additionally, they can be used as references in implementing high-quality nursing practices for such elderly people.

Complete genome sequence of Pseudomonas antarctica PAMC 27494, a bacteriocin-producing psychrophile isolated from Antarctica.

Antimicrobial-producing, cold-adapted microorganisms have great potential for biotechnological applications in food, pharmaceutical, and cosmetic industries. Pseudomonas antarctica PAMC 27494, a psychrophile exhibiting antimicrobial activity, was isolated from an Antarctic freshwater sample. Here we report the complete genome of P. antarctica PAMC 27494. The strain contains a gene cluster encoding microcin B which inhibits DNA regulations by targeting the DNA gyrase. PAMC 27494 may produce R-type pyocins and also contains a complete set of proteins for the biosynthesis of adenosylcobalamin and possibly induces plant growth by supplying pyrroloquinoline quionone molecules.

Difference in food and nutrient intakes in Korean elderly people according to chewing difficulty: using data from the Korea National Health and Nutrition Examination Survey 2013 (6th).

BACKGROUND/OBJECTIVES: Chewing difficulty is a factor contributing to a poor nutritional status in the elderly. The aim of this study was to examine disparities in food and nutrition intakes among Korean elderly people with and without chewing difficulty. SUBJECTS/METHODS: This study utilized data from the sixth Korea National Health and Nutrition Examination Survey conducted in 2013. The study subjects included males and females over 65 years of age who were not required to adhere to a special diet due to disease or sickness. They were divided into groups according to their chewing ability. Those who found chewing "very difficult" or "difficult", were combined to form the chewing difficulty group. Similarly, those who found chewing "moderately difficult", "easy", and "very easy" were combined to form the normal chewing group. RESULTS: Of the 999 subjects, 47.7% had chewing difficulties and the prevalence of chewing difficulty was higher in females than in males (P = 0.03) and higher in those 75 years of age and over than in younger individuals (P < 0.001). The chewing difficulty group had a significantly lower intake of fruits and vegetables (P < 0.05) and lower vitamin C and potassium intake than those in the normal group. Comparison of the percentages of Dietary Reference Intakes for Koreans (KDRIs) in the two groups indicated that the intake of most nutrients (energy, vitamin C, thiamin, riboflavin, niacin, calcium, phosphorus, sodium, potassium, and iron) were significantly lower in the chewing difficulty group than in the normal group. In particular, calcium intake was inadequate (51% of KDRIs) in the chewing difficulty group. CONCLUSIONS: The results indicate that chewing difficulty is closely related to food and nutrient intake in the elderly and can result in vitamin and mineral intake deficiencies. It is evident that the care of elderly subjects with chewing difficulty is essential for maintaining a healthy lifestyle.

Niche specialization of bacteria in permanently ice-covered lakes of the McMurdo Dry Valleys, Antarctica.

Perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica, are chemically stratified with depth and have distinct biological gradients. Despite long-term research on these unique environments, data on the structure of the microbial communities in the water columns of these lakes are scarce. Here, we examined bacterial diversity in five ice-covered Antarctic lakes by 16S rRNA gene-based pyrosequencing. Distinct communities were present in each lake, reflecting the unique biogeochemical characteristics of these environments. Further, certain bacterial lineages were confined exclusively to specific depths within each lake. For example, candidate division WM88 occurred solely at a depth of 15 m in Lake Fryxell, whereas unknown lineages of Chlorobi were found only at a depth of 18 m in Lake Miers, and two distinct classes of Firmicutes inhabited East and West Lobe Bonney at depths of 30 m. Redundancy analysis revealed that community variation of bacterioplankton could be explained by the distinct conditions of each lake and depth; in particular, assemblages from layers beneath the chemocline had biogeochemical associations that differed from those in the upper layers. These patterns of community composition may represent bacterial adaptations to the extreme and unique biogeochemical gradients of ice-covered lakes in the McMurdo Dry Valleys.

Influence of Soil Characteristics and Proximity to Antarctic Research Stations on Abundance of Antibiotic Resistance Genes in Soils.

Soil is an important environmental reservoir of antibiotic resistance genes (ARGs), which are increasingly recognized as environmental contaminants. Methods to assess the risks associated with the acquisition or transfer of resistance mechanisms are still underdeveloped. Quantification of background levels of antibiotic resistance genes and what alters those is a first step in understanding our environmental resistome. Toward this goal, 62 samples were collected over 3 years from soils near the 30-year old Gondwana Research Station and for 4 years before and during development of the new Jang Bogo Research Station, both at Terra Nova Bay in Antarctica. These sites reflect limited and more extensive human impact, respectively. A qPCR array with 384 primer sets targeting antibiotic resistance genes and mobile genetic elements (MGEs) was used to detect and quantify these genes. A total of 73 ARGs and MGEs encompassing eight major antibiotic resistance gene categories were detected, but most at very low levels. Antarctic soil appeared to be a common reservoir for seven ARGs since they were present in most samples (42%-88%). If the seven widespread genes were removed, there was a correlation between the relative abundance of MGEs and ARGs, more typical of contaminated sites. There was a relationship between ARG content and distance from both research stations, with a significant effect at the Jang Bogo Station especially when excluding the seven widespread genes; however, the relative abundance of ARGs did not increase over the 4 year period. Silt, clay, total organic carbon, and SiO2 were the top edaphic factors that correlated with ARG abundance. Overall, this study identifies that human activity and certain soil characteristics correlate with antibiotic resistance genes in these oligotrophic Antarctic soils and provides a baseline of ARGs and MGEs for future comparisons.

Complete Genome Sequence of Cryobacterium arcticum Strain PAMC 27867, Isolated from a Sedimentary Rock Sample in Northern Victoria Land, Antarctica.

Cryobacterium arcticum PAMC 27867, a psychrotolerant, Gram-positive bacterium, was isolated from a sedimentary rock sample collected at Eureka Spurs in northern Victoria Land, Antarctica. Here, we report the genome sequence of C. arcticum PAMC 27867.

Complete Genome Sequence of Psychrobacter alimentarius PAMC 27889, a Psychrophile Isolated from an Antarctic Rock Sample.

Psychrobacter alimentarius PAMC 27889, a Gram-negative, psychrophilic bacterium, was isolated from an Antarctic rock sample. Here, we report the complete genome of P. alimentarius PAMC 27889, which has the nonmevalonate methylerythritol phosphate pathway of terpenoid biosynthesis and a complete gene cluster for benzoate degradation.

Tumorigenicity Evaluation of Umbilical Cord Blood-derived Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) have been identified in multiple types of tissue and exhibit characteristic self-renewal and multi-lineage differentiation abilities. However, the possibility of oncogenic transformation after transplantation is concerning. In this study, we investigated the tumorigenic potential of umbilical cord blood-derived MSCs (hUCB-MSCs) relative to MRC-5 and HeLa cells (negative and positive controls, respectively) both in vitro and in vivo. To evaluate tumorigenicity in vitro, anchorage-independent growth was assessed using the soft agar colony formation assay. hUCB-MSCs and MRC-5 cells formed few colonies, while HeLa cells formed a greater number of larger colonies, indicating that hUCB-MSCs and MRC-5 cells do not have anchorage-independent proliferation potential. To detect tumorigenicity in vivo, hUCB-MSCs were implanted as a single subcutaneous injection into BALB/c-nu mice. No tumor formation was observed in mice transplanted with hUCB-MSCs or MRC-5 cells based on macroand microscopic examinations; however, all mice transplanted with HeLa cells developed tumors that stained positive for a human gene according to immunohistochemical analysis. In conclusion, hUCB-MSCs do not exhibit tumorigenic potential based on in vitro and in vivo assays under our experimental conditions, providing further evidence of their safety for clinical applications.