ABSTRACT
Herein, we report on the purification, characterization, and sequencing of catalase from Acinetobacter gyllenbergii 2P01AA, an extremely oxidation-resistant bacterium that was isolated from the Mars Phoenix spacecraft assembly facility. The Acinetobacter are dominant members of the microbial communities that inhabit spacecraft assembly facilities and consequently may serve as forward contaminants that could impact the integrity of future life-detection missions. Catalase was purified by using a 3-step chromatographic procedure, where mass spectrometry provided respective subunit and intact masses of 57.8 and 234.6 kDa, which were consistent with a small-subunit tetrameric catalase. Kinetics revealed an extreme pH stability with no loss in activity between pH 5 and 11.5 and provided respective kcat/Km and kcat values of â¼10(7) s(-1) M(-1) and 10(6) s(-1), which are among the highest reported for bacterial catalases. The amino acid sequence was deduced by in-depth peptide mapping, and structural homology suggested that the catalases from differing strains of A. gyllenbergii differ only at residues near the subunit interfaces, which may impact catalytic stability. Together, the kinetic, alkali-tolerant, and halotolerant properties of the catalase from A. gyllenbergii 2P01AA are significant, as they are consistent with molecular adaptations toward the alkaline, low-humidity, and potentially oxidizing conditions of spacecraft assembly facilities. Therefore, these results support the hypothesis that the selective pressures of the assembly facilities impact the microbial communities at the molecular level, which may have broad implications for future life-detection missions.
Subject(s)
Acinetobacter/enzymology , Alkalies/pharmacology , Catalase/isolation & purification , Catalase/metabolism , Spacecraft , Amino Acid Sequence , Catalase/antagonists & inhibitors , Catalase/chemistry , Electrophoresis, Polyacrylamide Gel , Enzyme Stability/drug effects , Hydrogen Peroxide/pharmacology , Hydrogen-Ion Concentration , Kinetics , Mass Spectrometry , Models, Molecular , Molecular Sequence Data , Oxidation-Reduction/drug effects , Sequence Homology, Amino Acid , Sodium Hydroxide/pharmacology , Structural Homology, Protein , TemperatureABSTRACT
The prevalence of postnatal depression in Bahrain is unknown and screening for known risk factors does not take place. This study estimated the prevalence of postnatal depressive symptoms and the associated risk factors among a random sample of Bahraini women attending primary health care centres with their babies for the 8-week child check-up. The Arabic version of the Edinburgh Postnatal Depression Scale (EPDS) was used with a cut-off score of > or = 12 for depression. The prevalence of postnatal depressive symptoms among 237 mothers was 37.1%. No significant relationships were identified between depression symptoms and any of demographic variables or pregnancy/birth characteristics studied. However, several psychosocial risk factors were significantly associated with postnatal depression and, after multiple regression analysis, a history of depressive symptoms and perceived lack of support from the husband remained significant factors. Further studies that include diagnostic assessments are needed to confirm these findings.
Subject(s)
Depression, Postpartum/prevention & control , Adolescent , Adult , Bahrain/epidemiology , Cross-Sectional Studies , Depression, Postpartum/epidemiology , Depression, Postpartum/psychology , Female , Humans , Infant, Newborn , Logistic Models , Male , Multivariate Analysis , Prevalence , Risk Factors , Social Support , Spouses/psychologyABSTRACT
The prevalence of postnatal depression in Bahrain is unknown and screening for known risk factors does not take place. This study estimated the prevalence of postnatal depressive symptoms and the associated risk factors among a random sample of Bahraini women attending primary health care centres with their babies for the 8-week child check-up. The Arabic version of the Edinburgh Postnatal Depression Scale [EPDS] was used with a cut-off score of >/=12 for depression. The prevalence of postnatal depressive symptoms among 237 mothers was 37.1%. No significant relationships were identified between depression symptoms and any of demographic variables or pregnancy/birth characteristics studied. However, several psychosocial risk factors were significantly associated with postnatal depression and, after multiple regression analysis, a history of depressive symptoms and perceived lack of support from the husband remained significant factors. Further studies that include diagnostic assessments are needed to confirm these findings
