143 research outputs found

    Twenty-three Species of Hypobarophilic Bacteria Recovered from Diverse Ecosystems Exhibit Growth under Simulated Martian Conditions at 0.7 kPa

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    Bacterial growth at low pressure is a new research area with implications for predicting microbial activity in clouds, the bulk atmosphere on Earth, and for modeling the forward contamination of planetary surfaces like Mars. Here we describe experiments on the recovery and identification of 23 species of bacterial hypobarophiles (def., growth under hypobaric conditions of approximately 1-2 kPa) in 11 genera capable of growth at 0.7 kPa. Hypobarophilic bacteria, but not archaea or fungi, were recovered from soil and non-soil ecosystems. The highest numbers of hypobarophiles were recovered from Arctic soil, Siberian permafrost, and human saliva. Isolates were identified through 16S rRNA sequencing to belong to the genera Carnobacterium, Exiguobacterium, Leuconostoc, Paenibacillus, and Trichococcus. The highest population of culturable hypobarophilic bacteria (5.1 x 104 cfu/g) was recovered from Colour Lake soils from Axel Heiberg Island in the Canadian arctic. In addition, we extend the number of hypobarophilic species in the genus Serratia to 6 type-strains that include S. ficaria, S. fonticola, S. grimesii, S. liquefaciens, S. plymuthica, and S. quinivorans. Microbial growth at 0.7 kPa suggests that pressure alone will not be growth-limiting on the martian surface, or in Earth's atmosphere up to an altitude of 34 km

    Identity and Coping: Deaf Sign Language Interpreters and Secondary Traumatic Stress

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    This article describes the results of a mixed methods study with 47 Deaf sign language interpreters (D-SLIs) and their experiences with secondary traumatic stress (STS). By replicating AUTHOR AND AUTHOR (2020) research, this study contributes data based on the unique experiences of Canadian and American Deaf interpreters and allows us to contrast the findings to the original study with non-Deaf interpreters (ND-SLIs). The findings reveal that the majority of D-SLIs did not experience clinical levels of STS, compassion satisfaction, anxiety, or burnout. In looking at the results, one-third of the D-SLIs showed comparable levels of STS and compassion satisfaction but less burnout than the ND-SLIs. Recommendations are identified, including the need to offer secondary traumatic stress specific training for all SLIs. The study has implications for all sign language interpreters and interpreter educators in designing educational programs and professional development

    UV-radiation-induced formation of DNA bipyrimidine photoproducts in Bacillus subtilis endospores and their repair during germination

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    The spore photoproduct (SP) is the main DNA lesion after UV-C irradiation, and its repair is crucial for the resistance of spores to UV. The aims of the present study were to assess the formation and repair of bipyrimidine photoproducts in spore DNA of various Bacillus subtilis strains using a sensitive HPLC tandem mass spectrometry assay. Strains deficient in nucleotide excision repair, spore photoproduct lyase, homologous recombination (recA), and with wild-type repair capability were investigated. Additionally, one strain deficient in the formation of major small, acid-soluble spore proteins (SASPs) was tested. In all SASP wild-type strains, UV-C irradiation generated almost exclusively SP (>95 %) but also a few by-photoproducts. In the major SASP-deficient strain, SP and by-photoproducts were generated in equal quantities. The status of the UV-induced bipyrimidine photoproducts was determined at different stages of spore germination. After a germination time of 60 min, >75% of the SP was repaired in wild-type strains and in the SASP-deficient strain, while half of the photoinduced SP was removed in the recA-deficient strain. SP-lyase-deficient spores repaired < 20% of the SP produced. Thus, SP lyase, with respect to nucleotide excision repair, has a remarkable impact on the removal of SP upon spore germination. [Int Microbiol 2007; 10(1):39-46

    Bacillus subtilis Spore Resistance to Simulated Mars Surface Conditions

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    In a Mars exploration scenario, knowing if and how highly resistant Bacillus subtilis spores would survive on the Martian surface is crucial to design planetary protection measures and avoid false positives in life-detection experiments. Therefore, in this study a systematic screening was performed to determine whether B. subtilis spores could survive an average day on Mars. For that, spores from two comprehensive sets of isogenic B. subtilis mutant strains, defective in DNA protection or repair genes, were exposed to 24 h of simulated Martian atmospheric environment with or without 8 h of Martian UV radiation [M(+)UV and M(-)UV, respectively]. When exposed to M(+)UV, spore survival was dependent on: (1) core dehydration maintenance, (2) protection of DNA by α/β-type small acid soluble proteins (SASP), and (3) removal and repair of the major UV photoproduct (SP) in spore DNA. In turn, when exposed to M(-)UV, spore survival was mainly dependent on protection by the multilayered spore coat, and DNA double-strand breaks represent the main lesion accumulated. Bacillus subtilis spores were able to survive for at least a limited time in a simulated Martian environment, both with or without solar UV radiation. Moreover, M(-)UV-treated spores exhibited survival rates significantly higher than the M(+)UV-treated spores. This suggests that on a real Martian surface, radiation shielding of spores (e.g., by dust, rocks, or spacecraft surface irregularities) might significantly extend survival rates. Mutagenesis were strongly dependent on the functionality of all structural components with small acid-soluble spore proteins, coat layers and dipicolinic acid as key protectants and efficiency DNA damage removal by AP endonucleases (ExoA and Nfo), non-homologous end joining (NHEJ), mismatch repair (MMR) and error-prone translesion synthesis (TLS). Thus, future efforts should focus on: (1) determining the DNA damage in wild-type spores exposed to M(+/-)UV and (2) assessing spore survival and viability with shielding of spores via Mars regolith and other relevant materials

    The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) family

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    The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) enzymes are secreted, multi-domain matrix-associated zinc metalloendopeptidases that have diverse roles in tissue morphogenesis and patho-physiological remodeling, in inflammation and in vascular biology. The human family includes 19 members that can be sub-grouped on the basis of their known substrates, namely the aggrecanases or proteoglycanases (ADAMTS1, 4, 5, 8, 9, 15 and 20), the procollagen N-propeptidases (ADAMTS2, 3 and 14), the cartilage oligomeric matrix protein-cleaving enzymes (ADAMTS7 and 12), the von-Willebrand Factor proteinase (ADAMTS13) and a group of orphan enzymes (ADAMTS6, 10, 16, 17, 18 and 19). Control of the structure and function of the extracellular matrix (ECM) is a central theme of the biology of the ADAMTS, as exemplified by the actions of the procollagen-N-propeptidases in collagen fibril assembly and of the aggrecanases in the cleavage or modification of ECM proteoglycans. Defects in certain family members give rise to inherited genetic disorders, while the aberrant expression or function of others is associated with arthritis, cancer and cardiovascular disease. In particular, ADAMTS4 and 5 have emerged as therapeutic targets in arthritis. Multiple ADAMTSs from different sub-groupings exert either positive or negative effects on tumorigenesis and metastasis, with both metalloproteinase-dependent and -independent actions known to occur. The basic ADAMTS structure comprises a metalloproteinase catalytic domain and a carboxy-terminal ancillary domain, the latter determining substrate specificity and the localization of the protease and its interaction partners; ancillary domains probably also have independent biological functions. Focusing primarily on the aggrecanases and proteoglycanases, this review provides a perspective on the evolution of the ADAMTS family, their links with developmental and disease mechanisms, and key questions for the future

    Converting Endangered Species Categories to Probabilities of Extinction for Phylogenetic Conservation Prioritization

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    Categories of imperilment like the global IUCN Red List have been transformed to probabilities of extinction and used to rank species by the amount of imperiled evolutionary history they represent (e.g. by the Edge of Existence programme). We investigate the stability of such lists when ranks are converted to probabilities of extinction under different scenarios.Using a simple example and computer simulation, we show that preserving the categories when converting such list designations to probabilities of extinction does not guarantee the stability of the resulting lists.Care must be taken when choosing a suitable transformation, especially if conservation dollars are allocated to species in a ranked fashion. We advocate routine sensitivity analyses

    Personality Traits, Self-Employment, and Professions

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    We investigate the effect of broad personality traits' - the Big Five - on an individua's decision to become self-employed. In particular, we test an overall indicator of the entrepreneurial personality. Since we find that the level of self-employment varies considerably across professions, we also perform the analysis for different types of professions, namely, those classified as being in the 'creative class' as compared to the noncreative class. The analysis is based on micro data for individuals of the German Socio Economic Panel (SOEP). We find a significant association between personality traits and the propensity be become self-employed. However, the strength of this link is fairly weak and differs across professions, indicating an important effect of an individual's profession on his or her decision to run an own business

    Modelling a Historic Oil-Tank Fire Allows an Estimation of the Sensitivity of the Infrared Receptors in Pyrophilous Melanophila Beetles

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    Pyrophilous jewel beetles of the genus Melanophila approach forest fires and there is considerable evidence that these beetles can detect fires from great distances of more than 60 km. Because Melanophila beetles are equipped with infrared receptors and are also attracted by hot surfaces it can be concluded that these infrared receptors are used for fire detection

    Racial differences in the prevalence of antenatal depression

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    OBJECTIVE: This study examined whether there were racial/ethnic differences in the prevalence of antenatal depression based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnostic criteria in a community-based sample of pregnant women. METHOD: Data were drawn from an ongoing registry of pregnant women receiving prenatal care at a university obstetric clinic from January 2004 through March 2010 (N =1997). Logistic regression models adjusting for sociodemographic, psychiatric, behavioral and clinical characteristics were used to examine racial/ethnic differences in antenatal depression as measured by the Patient Health Questionnaire. RESULTS: Overall, 5.1% of the sample reported antenatal depression. Blacks and Asian/Pacific Islanders were at increased risk for antenatal depression compared to non-Hispanic White women. This increased risk of antenatal depression among Blacks and Asian/Pacific Islanders remained after adjustment for a variety of risk factors. CONCLUSION: Results suggest the importance of race/ethnicity as a risk factor for antenatal depression. Prevention and treatment strategies geared toward the mental health needs of Black and Asian/Pacific Islander women are needed to reduce the racial/ethnic disparities in antenatal depression
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