鹤山南亚热带草坡生态系统的热量平衡

本文以广东鹤山丘陵综合试验站草坡为研究对象,分析了鹤山南亚热带草坡的能量平衡特征,主要结果如下：1．辐射平衡的各分量中,蒸发散耗热占净辐射的74.7％,其年变化幅度较大;湍流热通量占净辐射的21．2％,其月变化没有明显的规律,波动较大,土壤热通量与其它分量相比,其比重要小得多。2．虽然鹤山年幅射量和降雨量较多,但水热条件有几个月配合欠佳,使得草坡的净辐射能有90％以上用于地面以上植被和空气湍流交换所消耗,小气候条件较差,影响了这一生态系统的生产潜力的发挥。3．太阳辐射透过大气层以后,仅有4775．2MJm-2a-1左右的辐射能到达草坡,草坡反射了822．5MJm-2a-1,其净幅射收人为2915．6MJm-2a-1,净辐射收人中又有2077．8MJm-2a-1用于蒸散作用,618.1MJm-2a-1用于湍流热交换,87．5MJm-2a-1用于土壤热交换,植被贮热约38.8MJm-2a-1;用于净光合作用耗热93．4MJm-2a-1。     

JAK-STAT signaling mediates the senescence of cartilage-derived stem/progenitor cells

Journal of Molecular Histology - Aging is a major risk factor for degenerative joint diseases, such as osteoarthritis (OA). Previous studies have confirmed the link between senescent mesenchymal...     

Systems analysis of primary Sjögren's syndrome pathogenesis in salivary glands identifies shared pathways in human and a mouse model

Bone tissue has an exceptional quality to regenerate to native tissue in response to injury. However, the fracture repair process requires mechanical stability or a viable biological microenvironment or both to ensure successful healing to native tissue. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. Preclinical and clinical studies using biologic agents like recombinant bone morphogenetic proteins have demonstrated an efficacy similar or better than that of autologous bone graft in acute fracture healing. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications.     

Low SIRT3 Expression Correlates with Poor Differentiation and Unfavorable Prognosis in Primary Hepatocellular Carcinoma

SIRT3, a mitochondrial sirtuin belonging to nicotinamide adenine nucleotide (NAD) dependent deacetylases, is implicated in metabolism, longevity and carcinogenesis. SIRT3 expression and its significance in hepatocellular carcinoma (HCC) remain largely unclear. In this study, we demonstrated that SIRT3 expression in HCC tissue was much lower than that in paracarcinoma tissue, at both mRNA and protein levels. The cutoff value for low SIRT3 expression in HCC was defined according to receiver operating characteristic curve (ROC) analysis. As disclosed by immunohistochemistry (IHC) results, low SIRT3 expression was present in 67.3% (167/248) of HCC cases. Furthermore, low expression of SIRT3 was significantly correlated to differentiation (P = 0.013), clinical stage (P = 0.005), serum AFP level (P<0.01), tumor multiplicity (P = 0.026) and relapse (P = 0.028). Moreover, Kaplan-Meier analysis indicated that low SIRT3 expression associated with unfavorable overall survival (P<0.01) and recurrence-free survival (P = 0.004). The prognostic impact of SIRT3 was further confirmed by stratified survival analysis. Importantly, multivariate analysis revealed that low SIRT3 expression was an independent poor prognostic marker for overall survival (Hazard Ratio (HR) 0.555, 95% confidence interval (95% CI) 0.344–0.897, P = 0.016). Collectively, we conclude that SIRT3 is decreased in HCC and is a novel unfavorable marker for prognosis of patients with this fatal disease.     

The effects of 7-dehydrocholesterol on the structural properties of membranes

Smith-Lemli-Opitz syndrome, a congenital and developmental malformation disease, is typified by abnormal accumulation of 7-dehydrocholesterol (7DHC), the immediate precursor of cholesterol (CHOL), and depletion thereof. Knowledge of the effect of 7DHC on the biological membrane is, however, still fragmentary. In this study, large-scale atomistic molecular dynamics simulations, employing two distinct force fields, have been conducted to elucidate differences in the structural properties of a hydrated dimyristoylphosphatidylcholine bilayer due to CHOL and 7DHC. The present series of results indicate that CHOL and 7DHC possess virtually the same ability to condense and order membranes. Furthermore, the condensing and ordering effects are shown to be strengthened at increasing sterol concentrations.     

生态蛇胆美容霜对治疗蠕形螨病及护肤美容的效果观察

本文报道了微生态制剂－生态蛇胆美容霜治疗蠕形螨病及其合并症的观察结果。用透明胶带定量计数法检查１１３１人,其中检出毛囊虫阳性者４０４例,定居率为３５．７％,检出毛囊出共４１８只。对４０４例毛囊虫阳性分两组,即实验组,和对照组进行对照。结果实验组２５１例中只有２例仍为阳性,其余转为阴性。     

High auxin stimulates callus through SDG8-mediated histone H3K36 methylation in Arabidopsis

Callus induction,which results in fate transition in plant cells,is considered as the first and key step for plant regeneration.This process can be stimulated in different tissues by a callus-inducing medium(CIM),which contains a high concentration of phytohormone auxin.Although a few key regulators for callus induction have been identified,the multiple aspects of the regulatory mechanism driven by high levels of auxin still need further investigation.Here,we find that high auxin induces callus ...     

微生物群体感应抑制剂及其在海洋生态中的应用

微生物具有结构多样性和功能多样性,其生态行为受多种信号因子的调节,其一便是群体感应信号(Quorum sensing,QS)。QS可作为菌群的通讯语言调节多种生物学功能,包括微生物被膜(Biofilm)的形成、毒力因子的表达、抗生素的分泌以及活性物质的生成等。相比之下,群体感应抑制剂(Quorum sensing inhibitor,QSI)的作用与QS相反,它能阻断QS信号的合成或传递、降低细菌致病性、干扰Biofilm的生成、阻断QS级联效应,因而被广泛应用于医药、农业和环境等领域。本文聚焦QSI,对其来源、特性、作用机制的最新进展进行总结,并对其在海洋生态领域上的应用进行综述,以期为QSI物质的开发和海洋生态资源的有效利用提供新思路。     

Design and synthesis of highly selective pyruvate dehydrogenase complex E1 inhibitors as bactericides

In order to obtain PDHc-E1 inhibitors with high selectivity and efficacy, four series (7, 12, 15, and 19) of 35 novel 4-aminopyrimidine derivatives were rationally designed and synthesized based on the binding site of ThDP in E. coli PDHc-E1. 12, 15, and 19 were confirmed to be potent inhibitors against E. coli PDHc-E1. Selected compounds 12g, 12i, 15f, and 19a showed negligible inhibition against porcine PDHc-E1. To understand their selectivity, the interaction of inhibitor and E. coli PDHc-E1 or porcine PDHc-E1 was studied by molecular docking. The newly introduced acylhydrazone and N-phenylbenzamide moieties could form stronger interaction by hydrogen bond at the active site of E. coli PDHc-E1 compared with that of porcine PDHc-E1. A part of title compounds as potent PDHc-E1 inhibitors also exhibited notable antibacterial activity. In particular, 12e, 12f, 12g, 12o, and 19a exhibited 72–92% inhibition against Xanthomonas oryzae pv. Oryzae and Ralstonia solanacearum at 100?μg/mL, which was better than thiodiazole-copper (34 and 29%, respectively) and bismerthiazol (56 and 55%, respectively). The results proved that we could obtain effective bactericidal compounds as highly selective PDHc inhibitors by rational molecular design utilizing the binding model of active site of E. coli PDHc-E1.