Methyl lucidenate F isolated from the ethanol-soluble-acidic components of <Emphasis Type="Italic">Ganoderma lucidum</Emphasis> is a novel tyrosinase inhibitor

Tyrosinase is a key enzyme in the biosynthesis of melanin, and the use of inhibitors against tyrosinase can prevent hyperpigmentation by inhibiting enzymatic oxidation. However, the current use of tyrosine inhibitors is limited by their low activities and high toxicities. The aim of the present research was to develop novel whitening agents, or tyrosinase-targeted medicine, from a submerged culture of the fungus Ganoderma lucidum. Methyl lucidenate F was isolated from the ethanol-soluble-acidic components (ESACs) of G. lucidum, with the structure of ESACs elucidated via UV, LC-MS, and ¹³C-NMR spectral analysis. The tyrosinase inhibitory activity was measured using catechol as a substrate. Methyl lucidenate F displayed uncompetitive inhibition of the potato tyrosinase activity, for which Lineweaver-Burk plots revealed a maximum reaction rate (V _max) of 0.4367/min, Michaelis constant (K _m) of 6.765 mM and uncompetitive inhibition constant (K _i) of 19.22 μM. Meanwhile, methyl lucidenate F (tetra cyclic triterpenoid) exhibited high tyrosinase inhibitory activity, with an IC₅₀ of 32.23 μM. These results suggest that methyl lucidenate F may serve as a potential candidate for skin-whitening agents.     

Spatial distribution and abundances of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in mangrove sediments

We investigated the diversity, spatial distribution, and abundances of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in sediment samples of different depths collected from a transect with different distances to mangrove forest in the territories of Hong Kong. Both the archaeal and bacterial amoA genes (encoding ammonia monooxygenase subunit A) from all samples supported distinct phylogenetic groups, indicating the presences of niche-specific AOA and AOB in mangrove sediments. The higher AOB abundances than AOA in mangrove sediments, especially in the vicinity of the mangrove trees, might indicate the more important role of AOB on nitrification. The spatial distribution showed that AOA had higher diversity and abundance in the surface layer sediments near the mangrove trees (0 and 10 m) but lower away from the mangrove trees (1,000 m), and communities of AOA could be clustered into surface and bottom sediment layer groups. In contrast, AOB showed a reverse distributed pattern, and its communities were grouped by the distances between sites and mangrove trees, indicating mangrove trees might have different influences on AOA and AOB community structures. Furthermore, the strong correlations among archaeal and bacterial amoA gene abundances and their ratio with NH₄⁺, salinity, and pH of sediments indicated that these environmental factors have strong influences on AOA and AOB distributions in mangrove sediments. In addition, AOA diversity and abundances were significantly correlated with hzo gene abundances, which encodes the key enzyme for transformation of hydrazine into N₂ in anaerobic ammonium-oxidizing (anammox) bacteria, indicating AOA and anammox bacteria may interact with each other or they are influenced by the same controlling factors, such as NH₄⁺. The results provide a better understanding on using mangrove wetlands as biological treatment systems for removal of nutrients.     

点叶绵枣叶片培养及器官分化的研究

点叶绵枣叶外植体培养于MS 6-BA 1 PPm IBA 0.5 ppm培养基中,一月后不定芽仅从近轴面的叶表面产生。组织学的观察表明,不定芽起源于表皮细胞。     

南京地区繁缕和小繁缕群体的研究

繁缕(Stellaria media)和小繁缕(S.apetala)是两个形态相似的近缘种,有人把后者作为前者的亚种或变种来处理。本文通过对南京地区不同生境的三个自然群体和三个人工控制栽培群体的取样,以群体为单位,分别测算了叶、萼片、雄蕊、花瓣、果实和种子的8个数量性状的变异,绘制了多角形图;对花粉粒和种子进行了扫描;还通过花蕾套袋试验对种子活力作了检查。结果发现繁缕和小繁缕都是近亲繁殖植物,在形态上区别明显,对生态环境的要求基本相同,但小繁缕似更能耐受人为的践踏和刈割。     

内源性一氧化氮在内毒素引起的肺动脉高压和肺损伤中的作用

本实验观察了家兔静脉内注入内毒素的主要成分脂多糖(LPS)后平均动脉血压(MAP)、肺动脉压(PAP)及入、出肺血NO含量的变化,并观察了静脉内预注入NO生成抑制剂Nω-硝基-L-精氨酸(L-NNA)及诱生型NO生成抑制剂氨基胍(AG)后PAP和肺损伤的变化.结果观察到:家兔LPS注入后,MAP均明显下降,LPS注入后0.5、1、1.5、2h PAP明显增高(P<0.05).LPS注入后PAP的高峰期(1h)入肺血NO含量明显降低,出肺血NO无明显变化.与对照组相比,LPS注入后3h出肺血NO含量和5h入、出肺血NO含量均明显增多.相关分析表明,兔LPS注入前和LPS注入后1h PAP与入肺血NO含量呈明显的负相关,而LPS注入后 3h和5h两者相关不明显.静脉预注入L-NNA后,LPS处理组的动物PAP明显增高,入、出肺血丙二醛(MDA)含量也明显增高,动物生存率明显降低.肺组织光镜下可见肺萎陷和小血管淤血加重,白细胞明显增加.静脉预注入AG后,LPS处理组的动物MAP在3～5h明显增高,此时PAP无明显改变,但5h时血中MDA含量明显减低,5h时与LPS组相比肺萎陷和小血管淤血减轻,白细胞也明显减少.以上结果提示,内毒素入血后较早期阶段可出现PAP的升高,此时入肺血NO的减少是参与肺动脉压增高(PAH)的机制之一.家兔内毒素进入血后较早期阶段NO对减轻内毒素引起的PAH和肺损伤起重要作用,而较晚的时期当诱生型NO合酶(iNOS)诱生后释放的NO则参与内毒素引起的肺组织炎症反应和肺损伤.     

Identification of candidate chemosensory receptors in the antennal transcriptome of Tropidothorax elegans

Molecular Biology Reports - Chemosensory receptors in the dendritic membrane of olfactory cells are critical for the molecular recognition and discrimination of odorants. Tropidothorax elegans is a...     

Design,synthesis, quantum chemical studies and biological activity evaluation of pyrazole–benzimidazole derivatives as potent Aurora A/B kinase inhibitors

Novel pyrazole–benzimidazole derivatives have been designed and synthesized. The entire target compounds were determined against cancer cell lines U937, K562, A549, LoVo and HT29 and were screened for Aurora A/B kinase inhibitory activity in vitro. The compounds 7a, 7b, 7i, 7k and 7l demonstrated significant cancer cell lines and Aurora A/B kinase inhibitory activities. Molecular modeling studies suggested the derivatives have bound in the active site of Aurora A kinase through the formation of four hydrogen bonds. Quantum chemical studies were carried out on these compounds to understand the structural features essential for activity. The cellular activity of 7k was also tested by immunofluorescence.     

Association between CD14 Promoter -159C/T Polymorphism and the Risk of Sepsis and Mortality: A Systematic Review and Meta-Analysis

Background

Recent studies on the association between CD14-159C/T polymorphism and sepsis showed inconclusive results. Accordingly, we conducted a comprehensive literature search and a meta-analysis to determine whether the CD14-159C/T polymorphism conferred susceptibility to sepsis or was associated with increased risk of death from sepsis.

Methodology

Data were collected from the following electronic databases: PubMed, Embase, Medline, Web of Knowledge, and HuGE Navigator, with the last report up to June 15, 2012. The odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of association. We summarized the data on the association between CD14-159C/T polymorphism and sepsis in the overall population and subgroup by ethnicity and sepsis subtype.

Principal Findings

A total of 16 studies on sepsis morbidity (1369 cases and 2382 controls) and 4 studies on sepsis mortality (731 sepsis patients) met the inclusion criteria for meta-analysis. Overall analysis showed no strong evidences of association with sepsis susceptibility under any genetic model. However, slight associations were found in Asian populations (dominant model: OR = 1.38, 95%CI = 0.96–1.98, P = 0.08) and septic shock patients (dominant model: OR = 1.72, 95%CI 1.05–2.83, P = 0.03; allelic model: OR = 1.52, 95%CI 1.09–2.12, P = 0.01) in the stratified analysis. Moreover, there was borderline association between CD14-159C/T and sepsis mortality under the dominant genetic model (OR = 1.44, 95%CI = 0.98–2.11, P = 0.06).

Conclusions/Significance

This meta-analysis suggests that the CD14-159C/T polymorphism may not be a significant susceptibility factor in the risk of sepsis and mortality. Only weak associations were observed in Asian populations and septic shock patients. More studies based on larger sample sizes and homogeneous sepsis patients are needed to confirm these findings.