铜绿假单胞菌cntRLMN操纵子介导锌离子摄取的功能鉴定

【目的】本研究以铜绿假单胞菌PAO1 (Pseudomonas aeruginosa PAO1,菌种编号ATCC15692)为对象,研究cntRLMN在锌离子摄取中的功能。【方法】在ΔznuBC的基础上,以同源重组的方法构建了cntRLMN的各种突变菌株,通过质粒接合转移的方法构建其互补菌株及lacZ转录融合报告菌株,运用β-半乳糖苷酶酶活检测研究了Zur蛋白对cntRLMN的转录调控,凝胶阻滞实验(EMSA)检验Zur蛋白与cnt启动子及cnt启动子的突变片段的体外结合,并进一步通过生长曲线分析对cntRLMN中cntR、cntL、cntN等基因的锌离子摄取功能进行了分析和鉴定。最终,通过构建大蜡螟幼虫的侵染模型来研究cntRLMN对铜绿假单胞菌毒力发挥的影响。【结果】lacZ转录融合的酶活分析显示cntRLMN受Zur蛋白的负调控,其表达以Zur蛋白依赖的方式受锌离子饥饿的诱导;EMSA实验的结果显示cntRLMN的启动子可以与His-Zur结合形成DNA-蛋白质复合体,结合位点为GCGTTATAGTATATCAT;生长曲线和大蜡螟幼虫侵染实验的分析结果显示ZnuBC和CntRLMN的功能存在互补性,仅znuBC和cntRLMN双缺失突变时菌株在限锌培养条件下的生长和对大蜡螟幼虫的毒性才受到显著抑制,说明CntRLMN代表另一种独立的锌离子摄取系统。【结论】cntRLMN是受Zur直接负调控的另一种独立的铜绿假单胞菌锌离子摄取系统,对铜绿假单胞菌毒力的发挥起重要作用。     

Elevated Progesterone Levels on the Day of Oocyte Maturation May Affect Top Quality Embryo IVF Cycles

In contrast to the impact of elevated progesterone on endometrial receptivity, the data on whether increased progesterone levels affects the quality of embryos is still limited. This study retrospectively enrolled 4,236 fresh in vitro fertilization (IVF) cycles and sought to determine whether increased progesterone is associated with adverse outcomes with regard to top quality embryos (TQE). The results showed that the TQE rate significantly correlated with progesterone levels on the day of human chorionic gonadotropin (hCG) trigger (P = 0.009). Multivariate linear regression analysis of factors related to the TQE rate, in conventional IVF cycles, showed that the TQE rate was negatively associated with progesterone concentration on the day of hCG (OR was -1.658, 95% CI: -2.806 to -0.510, P = 0.005). When the serum progesterone level was within the interval 2.0–2.5 ng/ml, the TQE rate was significantly lower (P <0.05) than when the progesterone level was < 1.0 ng/ml; similar results were obtained for serum progesterone levels >2.5 ng/ml. Then, we choose a progesterone level at 1.5ng/ml, 2.0 ng/ml and 2.5 ng/ml as cut-off points to verify this result. We found that the TQE rate was significantly different (P <0.05) between serum progesterone levels < 2.0 ng/ml and >2.0 ng/ml. In conclusion, the results of this study clearly demonstrated a negative effect of elevated progesterone levels on the day of hCG trigger, on TQE rate, regardless of the basal FSH, the total gonadotropin, the age of the woman, or the time of ovarian stimulation. These data demonstrate that elevated progesterone levels (>2.0 ng/ml) before oocyte maturation were consistently detrimental to the oocyte.     

Possible target‐related proteins and signal network of bufalin in A549 cells suggested by both iTRAQ‐based and label‐free proteomic analysis

Bufalin (BF) exhibited antiproliferation and antimigration effects on human A549 lung cancer cells. To search its target‐related proteins, protein expression profiles of BF‐treated and control cells were compared using two quantitative proteomic methods, iTRAQ‐based and label‐free proteomic analysis. A total of 5428 proteins were identified in iTRAQ‐based analysis while 6632 proteins were identified in label‐free analysis. The number of common identified proteins of both methods was 4799 proteins. By application of 1.20‐fold for upregulated and 0.83‐fold for downregulated cutoff values, 273 and 802 differentially expressed proteins were found in iTRAQ‐based and label‐free analysis, respectively. The number of common differentially expressed proteins of both methods was 45 proteins. Results of bioinformational analysis using Metacore^TM showed that the two proteomic methods were complementary and both suggested the involvement of oxidative stress and regulation of gene expression in the effects of BF, and fibronectin‐related pathway was suggested to be an important pathway affected by BF. Western blotting assay results confirmed BF‐induced change in levels of fibronectin and other related proteins. Overexpression of fibronectin by plasmid transfection ameliorated antimigration effects of BF. Results of the present study provided information about possible target‐related proteins and signal network of BF.     

Physiological,biochemical, and proteome profiling reveals key pathways underlying the drought stress responses of Hippophae rhamnoides

The effects of drought on plant growth and development are occurring as a result of climate change and the growing scarcity of water resources. Hippophae rhamnoides has been exploited for soil and water conservation for many years. However, the outstanding drought‐resistance mechanisms possessed by this species remain unclear. The protein, physiological, and biochemical responses to medium and severe drought stresses in H. rhamnoides seedlings are analyzed. Linear decreases in photosynthesis rate, transpiration rate, and the content of indole acetic acid in roots, as well as a linear increase in the contents of abscisic acid, superoxide dismutase, glutathione reductase, and zeatin riboside in leaves are observed as water potential decreased. At the same time, cell membrane permeability, malondialdehyde, stomatal conductance, water use efficiency, and contents of zeatin riboside in roots and indole acetic acid in leaves showed nonconsistent changes. DIGE and MS/MS analysis identified 51 differently expressed protein spots in leaves with functions related to epigenetic modification and PTM in addition to normal metabolism, photosynthesis, signal transduction, antioxidative systems, and responses to stimuli. This study provides new insights into the responses and adaptations in this drought‐resistant species and may benefit future agricultural production.     

Augmentation of Autoantibodies by Helicobacter pylori in Parkinson’s Disease Patients May Be Linked to Greater Severity

Parkinson''s disease (PD) is the second most common chronic and progressive neurodegenerative disorder. Its etiology remains elusive and at present only symptomatic treatments exists. Helicobacter pylori chronically colonizes the gastric mucosa of more than half of the global human population. Interestingly, H. pylori positivity has been found to be associated with greater of PD motor severity. In order to investigate the underlying cause of this association, the Sengenics Immunome protein array, which enables simultaneous screening for autoantibodies against 1636 human proteins, was used to screen the serum of 30 H. pylori-seropositive PD patients (case) and 30 age- and gender-matched H. pylori-seronegative PD patients (control) in this study. In total, 13 significant autoantibodies were identified and ranked, with 8 up-regulated and 5 down-regulated in the case group. Among autoantibodies found to be elevated in H. pylori-seropositive PD were included antibodies that recognize Nuclear factor I subtype A (NFIA), Platelet-derived growth factor B (PDGFB) and Eukaryotic translation initiation factor 4A3 (eIFA3). The presence of elevated autoantibodies against proteins essential for normal neurological functions suggest that immunomodulatory properties of H. pylori may explain the association between H. pylori positivity and greater PD motor severity.     

Galectin-3 Inhibition Is Associated with Neuropathic Pain Attenuation after Peripheral Nerve Injury

Neuropathic pain remains a prevalent and persistent clinical problem because it is often poorly responsive to the currently used analgesics. It is very urgent to develop novel drugs to alleviate neuropathic pain. Galectin-3 (gal3) is a multifunctional protein belonging to the carbohydrate-ligand lectin family, which is expressed by different cells. Emerging studies showed that gal3 elicits a pro-inflammatory response by recruiting and activating lymphocytes, macrophages and microglia. In the study we investigated whether gal3 inhibition could suppress neuroinflammation and alleviate neuropathic pain following peripheral nerve injury. We found that L5 spinal nerve ligation (SNL) increases the expression of gal3 in dorsal root ganglions at the mRNA and protein level. Intrathecal administration of modified citrus pectin (MCP), a gal3 inhibitor, reduces gal3 expression in dorsal root ganglions. MCP treatment also inhibits SNL-induced gal3 expression in primary rat microglia. SNL results in an increased activation of autophagy that contributes to microglial activation and subsequent inflammatory response. Intrathecal administration of MCP significantly suppresses SNL-induced autophagy activation. MCP also inhibits lipopolysaccharide (LPS)-induced autophagy in cultured microglia in vitro. MCP further decreases LPS-induced expression of proinflammatory mediators including IL-1β, TNF-α and IL-6 by regulating autophagy. Intrathecal administration of MCP results in adecreased mechanical and cold hypersensitivity following SNL. These results demonstrated that gal3 inhibition is associated with the suppression of SNL-induced inflammatory process andneurophathic pain attenuation.     

Nutritional Deficiencies,the Absence of Information and Caregiver Shortcomings: A Qualitative Analysis of Infant Feeding Practices in Rural China

MethodologyWe interviewed sixty caregivers participating in a large survey on child health and nutrition. We conducted three waves of interviews with children’s primary caregivers in seventeen rural villages within four nationally-designated poverty counties in the southern part of Shaanxi Province.ResultsThe qualitative analysis reveals that poor complementary feeding practices are common across our sample. Information gathered from our interviews suggests that complementary feeding practices are impeded by two constraints: absence of understanding topics related to infant health and nutrition under caregivers, as well as inadequate sources of information on these topics. Poverty does not appear to constrain child feeding practices.ConclusionOur results uncover lack of proper knowledge on infant and child nutrition among rural caregivers in China. This situation causes them to fail incorporating micronutrient rich foods in their children''s diet. Age-appropriate complementary feeding can stimulate children’s physical and cognitive development, but in its absence it leads to iron-deficiency anemia. We suggest that steps be taken to educate caregivers to improve complementary feeding of their infants and children.