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151.
152.
Hai-Bo Jiang Wen-Jing Lou Wen-Ting Ke Wei-Yu Song Neil M Price Bao-Sheng Qiu 《The ISME journal》2015,9(2):297-309
Cyanobacteria are globally important primary producers that have an exceptionally large iron requirement for photosynthesis. In many aquatic ecosystems, the levels of dissolved iron are so low and some of the chemical species so unreactive that growth of cyanobacteria is impaired. Pathways of iron uptake through cyanobacterial membranes are now being elucidated, but the molecular details are still largely unknown. Here we report that the non-siderophore-producing cyanobacterium Synechocystis sp. PCC 6803 contains three exbB-exbD gene clusters that are obligatorily required for growth and are involved in iron acquisition. The three exbB-exbDs are redundant, but single and double mutants have reduced rates of iron uptake compared with wild-type cells, and the triple mutant appeared to be lethal. Short-term measurements in chemically well-defined medium show that iron uptake by Synechocystis depends on inorganic iron (Fe′) concentration and ExbB-ExbD complexes are essentially required for the Fe′ transport process. Although transport of iron bound to a model siderophore, ferrioxamine B, is also reduced in the exbB-exbD mutants, the rate of uptake at similar total [Fe] is about 800-fold slower than Fe′, suggesting that hydroxamate siderophore iron uptake may be less ecologically relevant than free iron. These results provide the first evidence that ExbB-ExbD is involved in inorganic iron uptake and is an essential part of the iron acquisition pathway in cyanobacteria. The involvement of an ExbB-ExbD system for inorganic iron uptake may allow cyanobacteria to more tightly maintain iron homeostasis, particularly in variable environments where iron concentrations range from limiting to sufficient. 相似文献
153.
Theresa W. Gauthier Sowmya S. Mohan Teresa S. Gross Frank L. Harris David M. Guidot Lou Ann S. Brown 《PloS one》2015,10(5)
The accumulation of fatty acid ethyl esters (FAEEs) in meconium of term newborns has been described as one potential biomarker of maternal alcohol use during pregnancy. FAEEs accumulate in multiple alcohol-exposed fetal tissues and in the placenta. Limited research has focused on the identification of the premature newborn exposed to alcohol in utero. We hypothesized that maternal alcohol use occurs in a significant proportion of premature deliveries and that this exposure can be detected as elevated placental FAEEs. The goals of this study were to 1) determine the prevalence of maternal alcohol use in the premature newborn and 2) investigate whether placental FAEEs could identify those newborns with fetal alcohol exposure. This prospective observational study evaluated 80 placentas from 80 women after premature delivery. Subjects were interviewed for alcohol intake and placental FAEEs were quantified via GC/MS. Receiver Operator Characteristic (ROC) Curves were generated to evaluate the ability of placental FAEEs to predict maternal drinking during pregnancy. Adjusted ROC curves were generated to adjust for gestational age, maternal smoking, and illicit drug use. 30% of the subjects admitted to drinking alcohol during pregnancy and approximately 14% answered questions indicative of problem drinking (designated AUDIT+). The specific FAEEs ethyl stearate and linoleate, as well as combinations of oleate + linoleate + linolenate (OLL) and of OLL + stearate, were significantly (p<0.05) elevated in placentas from AUDIT+ pregnancies. Adjusted ROC Curves generated areas under the curve ranging from 88–93% with negative predictive values of 97% for AUDIT+ pregnancies. We conclude that nearly one third of premature pregnancies were alcohol-exposed, and that elevated placental FAEEs hold great promise to accurately determine maternal alcohol use, particularly heavy use, in pregnancies complicated by premature delivery. 相似文献
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157.
Purpose
Unbalanced inflammatory response and lymphocyte apoptosis is associated with high mortality in septic patients. Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor superfamily, is an anti-inflammatory and anti-apoptotic factor. Recently, DcR3 expression was found to be increased in septic patients. This study evaluated the therapeutic effect and mechanisms of DcR3 on cecal ligation and puncture (CLP)-induced sepsis in mice.Methods
C57BL/6 mice were subjected to CLP-induced polymicrobial sepsis. DcR3 Fc was intravenously injected 30 min before and 6 h after CLP. Bacterial clearance, cytokine production, histology, lymphocyte apoptosis and survival were evaluated. Furthermore, we investigated the systemic effects of DcR3 in in vitro lymphocyte apoptosis regulation.Results
Our results demonstrated that DcR3 protein treatments significantly improved survival in septic mice (p <0.05). Treatment with DcR3 protein significantly reduced the inflammatory response and decreased lymphocyte apoptosis in the thymus and spleen. Histopathological findings of the lung and liver showed milder impairment after DcR3 administration. In vitro experiments showed that DcR3 Fc inhibited Fas-FasL mediated lymphocyte apoptosis.Conclusions
Treatment with the DcR3 protein protects mice from sepsis by suppressing the inflammatory response and lymphocyte apoptosis. DcR3 protein may be useful in treatment of sepsis. 相似文献158.
Homologous recombination and non-homologous end joining are two major DNA double-strand-break repair pathways. While HR-mediated repair requires a homologous sequence as the guiding template to restore the damage site precisely, NHEJ-mediated repair ligates the DNA lesion directly and increases the risk of losing nucleotides. Therefore, how a cell regulates the balance between HR and NHEJ has become an important issue for maintaining genomic integrity over time. Here we report that SIRT1-dependent KAP1 deacetylation positively regulates NHEJ. We show that up-regulation of KAP1 attenuates HR efficiency while promoting NHEJ repair. Moreover, SIRT1-mediated KAP1 deacetylation further enhances the effect of NHEJ by stabilizing its interaction with 53BP1, which leads to increased 53BP1 focus formation in response to DNA damage. Taken together, our study suggests a SIRT1-KAP1 regulatory mechanism for HR-NHEJ repair pathway choice. 相似文献
159.
Aims
To investigate the association of demographic, clinical and psychosocial variables with levels of anxiety and depression in participants wearing an ocular prosthesis after eye enucleation.Methods
This cross-sectional study included 195 participants with an enucleated eye who were attending an ophthalmic clinic for prosthetic rehabilitation between July and November 2014. Demographic and clinical data, and self-reported feelings of shame, sadness and anger were collected. Participants also completed the National Eye Institute Visual Function Questionnaire, the Facial Appearance subscale of the Negative Physical Self Scale, and the Hospital Anxiety and Depression Scale. Regression models were used to identify the factors associated with anxiety and depression.Results
The proportion of participants with clinical anxiety was 11.8% and clinical depression 13.8%. More anxiety and depression were associated with poorer vision-related quality of life and greater levels of appearance concerns. Younger age was related to greater levels of anxiety. Less educated participants and those feeling more angry about losing an eye are more prone to experience depression. Clinical variables were unrelated to anxiety or depression.Conclusions
Anxiety and depression are more prevalent in eye-enucleated patients than the general population, which brings up the issues of psychiatric support in these patients. Psychosocial rather than clinical characteristics were associated with anxiety and depression. Longitudinal studies need to be conducted to further elucidate the direction of causality before interventions to improve mood states are developed. 相似文献160.