越南蒲马特国家自然保护区植物区系特征

蒲马特国家公园位于越南中部的义安省,国际著名的生物多样性极为丰富的Annamite山系的核心地区。基于植物标本鉴定,在蒲马特国家公园保护区内记录有维管束植物184科,771属,2018种(包括变种和亚种)。该植物区系占整个越南植物区系的21 %,其中的木兰亚纲植物占该植物区系总种数的90 .98 %,总属数的90 .4 %及总科数的83 .7 %。含种数最多的科包括茜草科(37属/129种) ,大戟科(36/99) ,兰科(34/73) ,樟科(11/66) ,桑科(10/54) ,蝶形花科(24/51) ,壳斗科(4/50) ,紫金牛科(5/48)及芸香科(14/45)等。在种子植物地理成分组成上,有11个科的分布区类型及14属分布区类型,其中,热带分布型分别占总科数的85 .6 %和总属数的90 .1 %,并且在其热带分布属中,热带亚洲成分占总属数的31 .4 %。这些特征显示,蒲马特国家公园植物区系是典型热带性质的植物区系,属于热带亚洲植物区系的一部分。     

Genome-Guided Investigation Provides New Insights into Secondary Metabolites of Streptomyces Parvulus SX6 from Aegiceras Corniculatum

Whole-genome sequencing and genome mining are recently considered an efficient approach to shine more light on the underlying secondary metabolites of Streptomyces. The present study unearths the biosynthetic potential of endophytic SX6 as a promising source of biologically active substances and plant-derived compounds for the first time. Out of 38 isolates associated with Aegiceras corniculatum (L.) Blanco, Streptomyces parvulus SX6 was highly active against Pseudomonas aeruginosa ATCC® 9027™ and methicillin-resistant Staphylococcus epidermidis (MRSE) ATCC® 35984™. Additionally, S. parvulus SX6 culture extract showed strong cytotoxicity against Hep3B, MCF-7, and A549 cell lines at a concentration of 30 μg/ml, but not in non-cancerous HEK-293 cells. The genome contained 7.69 Mb in size with an average G + C content of 72.8% and consisted of 6,779 protein-coding genes. AntiSMASH analysis resulted in the identification of 29 biosynthetic gene clusters (BGCs) for secondary metabolites. Among them, 4 BGCs showed low similarity (28–67% of genes show similarity) to actinomycin, streptovaricin, and polyoxypeptin gene clusters, possibly attributed to antibacterial and anticancer activities observed. In addition, the complete biosynthetic pathways of plant-derived compounds, including daidzein and genistein were identified using genome mining and HPLC-DAD-MS analysis. These findings portray an exciting avenue for future characterization of promising secondary metabolites from mangrove endophytic S. parvulus.     

Cyanobacterial metabolites with bioactivity against photosynthesis in cyanobacteria, algae and higher plants

Cyanobacteria produce a large number and variety of bioactive allelochemical substances, with a diverse range of biological activities and chemical structures, and with effects on many biochemical processes within cells. An increasing number of such metabolites is being found to be directed against oxygenic photosynthetic processes, which, in the microbial world, are unique to algae and cyanobacteria. Such chemicals are likely to be involved in regulating natural populations, and are potentially useful as biochemical tools, and as herbicidal or biocontrol agents. This revised version was published online in June 2006 with corrections to the Cover Date.     

Influenza Infection Rates,Measurement Errors and the Interpretation of Paired Serology

Serological studies are the gold standard method to estimate influenza infection attack rates (ARs) in human populations. In a common protocol, blood samples are collected before and after the epidemic in a cohort of individuals; and a rise in haemagglutination-inhibition (HI) antibody titers during the epidemic is considered as a marker of infection. Because of inherent measurement errors, a 2-fold rise is usually considered as insufficient evidence for infection and seroconversion is therefore typically defined as a 4-fold rise or more. Here, we revisit this widely accepted 70-year old criterion. We develop a Markov chain Monte Carlo data augmentation model to quantify measurement errors and reconstruct the distribution of latent true serological status in a Vietnamese 3-year serological cohort, in which replicate measurements were available. We estimate that the 1-sided probability of a 2-fold error is 9.3% (95% Credible Interval, CI: 3.3%, 17.6%) when antibody titer is below 10 but is 20.2% (95% CI: 15.9%, 24.0%) otherwise. After correction for measurement errors, we find that the proportion of individuals with 2-fold rises in antibody titers was too large to be explained by measurement errors alone. Estimates of ARs vary greatly depending on whether those individuals are included in the definition of the infected population. A simulation study shows that our method is unbiased. The 4-fold rise case definition is relevant when aiming at a specific diagnostic for individual cases, but the justification is less obvious when the objective is to estimate ARs. In particular, it may lead to large underestimates of ARs. Determining which biological phenomenon contributes most to 2-fold rises in antibody titers is essential to assess bias with the traditional case definition and offer improved estimates of influenza ARs.     

A chimeric mutant analysis in yeast cells suggests BiP independent regulation of the mammalian endoplasmic reticulum-stress sensor IRE1α

An endoplasmic reticulum (ER)-located transmembrane protein, Ire1, triggers cytoprotective events upon ER stress. Chimeric yeast Ire1 carrying the luminal domain of the mammalian major Ire1 paralogue IRE1α is upregulated in ER-stressed yeast cells, but is poorly associated with the ER-located chaperone BiP even under non-stressed conditions. This observation contradicts the theory that BiP is the master regulator of IRE1α.     

Comparing Biochar Application Methods for Switchgrass Yield and C Sequestration on Contrasting Marginal Lands in Pennsylvania,USA

To avoid competition with food crops, biofuel feedstocks may need to be produced on economically marginal lands where yields are limited and replacement of existing vegetation will reduce soil C, foregoing some CO₂ emission savings. Therefore, our first goal was to determine whether biochar application to marginal lands could improve switchgrass yield while sequestering sufficient soil C to eliminate the negative impact of cultivation. Because it may be difficult to obtain large quantities of biochar, our second goal was to compare small, incremental and large, all-at-once biochar applications. Our third goal was to determine whether biochar had any negative effects on earthworms, mycorrhizal fungi, soil bacteria, soil fungi, and soil enzyme activity. We grew switchgrass at two sites with poorly drained soils and two sites with excessively drained soils. Irrespective of site, biochar significantly increased yield when we rototilled in the entire amount before planting but not when we applied it incrementally between crop rows using a chisel plow. Biochar increased soil C stocks, in some cases increasing it beyond that found in soils of intact marginal land vegetation. Nevertheless, mixing biochar with soil had little or no impact on earthworm activity, mycorrhizal colonization, soil bacterial and fungal communities, and soil enzyme activities. We conclude that biochar may be part of an effective strategy for producing switchgrass on marginal lands, but the choice of application method depends on the relative importance of several considerations including biochar availability, switchgrass yield, C sequestration, soil erosion, and ease of application.     

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone resorption. Osteoclasts can be generated in vitro from monocyte/macrophage precursor cells in the presence of certain cytokines, which promote survival and differentiation. Here, both in vivo and in vitro techniques are demonstrated, which allow scientists to study different cytokine contributions towards osteoclast differentiation, signaling, and activation. The minicircle DNA delivery gene transfer system provides an alternative method to establish an osteoporosis-related model is particularly useful to study the efficacy of various pharmacological inhibitors in vivo. Similarly, in vitro culturing protocols for producing osteoclasts from human precursor cells in the presence of specific cytokines enables scientists to study osteoclastogenesis in human cells for translational applications. Combined, these techniques have the potential to accelerate drug discovery efforts for osteoclast-specific targeted therapeutics, which may benefit millions of osteoporosis and arthritis patients worldwide.     

Protocorm-like body formation,stem elongation,and enhanced growth of Anthurium andraeanum ‘Tropical’ plantlet on medium containing silver nanoparticles

In Vitro Cellular & Developmental Biology - Plant - In this study, a new method for shoot regeneration via protocorm-like bodies (PLBs) is described. Shoot proliferation using stem elongation...     

Chronotolerance of a Nickel (II) Complex with the 5-Methyl 2-Furaldehyde Thiosemicarbazone Ligand in Male Swiss Mice

In vitro nickel (II) complex presents antimitotic effects. In this work, we have studied the in vivo seasonal effects of nickel (II), ligand and the complex [NiCl