建构共生的初中化学课堂

共生的课堂应是师生之间相互依赖、相互成就,以化学学科为载体,教育者和学习者共同参与课程建构、学习建构、活动建构,共同学习和实践的场所。共生化学的核心理念是教学相长,即“学然后知不足,教然后知困。知不足,能自反也;知困,然后能自强也”。

三种石黄衣的共生菌化学多样性及其系统生物学意义

本文对丽石黄衣(Xanthoria elegans)、中国石黄衣(X. mandschurica)和刺盘石黄衣(X. alfredi)的共生菌,尤其是刺盘石黄衣共生菌的分离培养物进行了首次研究。对于上述三种地衣体及其共生菌的化学物质进行了比较分析。研究与分析结果表明,三种石黄衣地衣体化学物质,即蒽醌类化合物完全一致。此外, Lindblom从15种北美石黄衣地衣体中检测出了彼此一致的5种蒽醌类化合物。因此,该作者认为石黄衣属的蒽醌类化合物不具有种级分类学意义。本文的实验结果也证实了这一观点。但是,本文对于通过子囊孢子释放法获得的中国三种石黄衣共生菌的化学物质进行了检测和分析,其结果呈现出比较丰富的多样性。其中刺盘石黄衣共生菌化学物质与丽石黄衣和中国石黄衣共生菌所含的化学物质存在明显差异。因而,刺盘石黄衣共生菌化学物质在该种地衣的鉴定中具有重要的参考价值。 此外,文章亦检测和分析了丽石黄衣的10株共生菌化学物质。供试菌株均在相同培养条件和培养时间下获得。其化学物质的TLC图谱,除Nos. 5, 7, 及10稍有差异外,几乎完全一致。由此看来,它们稳定性也是比较明显的。 上述结果提示我们,在地衣系统生物学研究中,除了对于地衣体化学物质进行常规检测与分析之外。

固态质子导体型燃料电池反应器

将固态质子导体型燃料电池作为新型反应器用于合成化学品,产物选择性高,能耗低,可以实现电能与化学品共生。通过对反应器操作参数的调变,可以获得预期的化学产品及相应的电化学特性。本工作综述了固态质子导体型燃料电池反应器在简单无机物加氢、具有不饱和键脂肪族和芳香族化合物加氢、醇脱氢以及烷烃脱氢等反应中的应用。随着对该反应过程认识的不断深入,可望开辟一条崭新的化学品合成途径。

Dihydrochalcones and phenanthrene derivatives from Fissistigma bracteolatum

Three dihydrochalcones derivatives 1-3, flavone 4 and phenanthrene derivative 5 were isolated, together with 9 known compofinds, from the air-dried root bark of Fissistigma bracteolatum Chatterjee. Their structures were determined by spectroscopic （NMR, MS） and chemical methodologies.

Construction of a Metagenomic DNA Library of Sponge Symbionts and Screening of Antibacterial Metabolites

To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DNA and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.

Improving Simulation of the Terrestrial Carbon Cycle of China in Version 4.5 of the Community Land Model Using a Revised V_(cmax) Scheme

The maximum rate of carboxylation （Vcax） is a key photosynthetic parameter for gross primary produc- tion （GPP） estimation in terrestrial biosphere models. A set of observation-based Vcax values, which take the ni- trogen limitation on photosynthetic rates into consideration, are used in version 4.5 of the Community Land Model （CLM4.5）. However, CLM4.5 with carbon-nitrogen （CN） biogeochemistry （CLM4.5-CN） still uses an inde- pendent decay coefficient for nitrogen after the photosyn- thesis calculation. This means that the nitrogen limitation on the carbon cycle is accounted for twice when CN bio- geochemistry is active. Therefore, to avoid this double nitrogen down-regulation in CLM4.5-CN, the original Vcmax scheme is revised with a new one that only accounts for the transition between Vcmax and its potential value （without nitrogen limitation）. Compared to flux tower- based observations, the new Vcmax scheme reduces the root-mean-square error （RMSE） in GPP for China's Mainland by 13.7 g C m-2 yr-1, with a larger decrease over humid areas （39.2 g C m 2 yr-1）. Moreover, net primary production and leaf area index are also improved, with reductions in RMSE by 0.8% and 11.5%, respectively.

High-rate removal of As(Ⅲ) from aqueous system with sulfhydryl magnetic biological bamboo charcoal nanocomposites prepared by chemical co-precipitation method

Sulfhydryl magnetic biological bamboo charcoal nanocomposite(BBC@nFe-SH)was prepared by chemical co-precipitation method for the robust capture of As(Ⅲ)from aqueous solutions.The novel BBC@nFe-SH shows favorable magnetic field strength(83376 A/m),which enables BBC@nFe-SH to be quickly recovered from aqueous solution.The maximum As(Ⅲ)adsorption capacity is as high as 98.63 mg/g at pH 5.0 and 40°C,reaching reaction equilibrium within 120 min.Various characterizations(e.g.,SEM,FTIR,VSM and XPS)suggest that As(Ⅲ)prefers to coordinate with surface oxygen groups bonded to the surface.BBC@nFe-SH displayed high stability and recyclability throughout the removal process,which could be easily activated by 1 mol/L NaOH after usage.Thus,the novel BBC@nFe-SH has promising applications for As(Ⅲ)treatment.

A Macaca mulatta model of fulminant hepatic failure

AIM:To establish an appropriate primate model of fulminant hepatic failure (FHF).METHODS:We have,for the first time,established a large animal model of FHF in Macaca mulatta by intraperitoneal infusion of amatoxin and endotoxin.Clinical features,biochemical indexes,histopathology and iconography were examined to dynamically investigate the progress and outcome of the animal model.RESULTS:Our results showed that the enzymes and serum bilirubin were markedly increased and the enzyme-bilirubin segregation emerged 36 h after toxin administration.Coagulation activity was significantly decreased.Gradually deteriorated parenchymal abnormality was detected by magnetic resonance imaging (MRI) and ultrasonography at 48 h.The liver biopsy showed marked hepatocyte steatosis and massive parenchymal necrosis at 36 h and 49 h,respectively.The autopsy showed typical yellow atrophy of the liver.Hepatic encephalopathy of the models was also confirmed by hepatic coma,MRI and pathological changes of cerebral edema.The lethal effects of the extrahepatic organ dysfunction were ruled out by their biochemical indices,imaging and histopathology.CONCLUSION:We have established an appropriate large primate model of FHF,which is closely similar to clinic cases,and can be used for investigation of the mechanism of FHF and for evaluation of potential medical therapies.

Isolation and Identification of Nicotiflorin and Narcissin from the Aerial Parts of Peucedanum aucheri Boiss.

Peucedanum aucheri Boiss. （Apiaceae） is a herbaceous wild plant native to Iran and is used in Iranian folk medicine as a diuretic and for the treatment of kidney disorders. Phytochemical investigation of different extracts prepared from the aerial part of P. aucheri Boiss. resulted to the isolation of two main flavonol glycosides from methanolic extract. Using comprehensive spectroscopic methods, including 1D and 2D nuclear magnetic resonance （NMR） spectroscopy and mass spectroscopy, chemical structure of isolated compounds were determined as kaempfrol-3-o-rutinoside （nicotiflorin） and isorhamnetin-3-o-rutinoside （narcissin）. Although narcissin has previously been isolated from P. ruthenicum, to the best of our knowledge, isolation of nicotiflorin from Peucedanum genus is reported for the first time.

A coevolutionary framework based on temporal and spatial ecology of host-parasite interactions:A missing link in studies of brood parasitism

A central tenet of coevolutionary theory,including theory of the coevolutionary relationship between brood parasites and their hosts,is that temporal and spatial patterns may reveal important information about ecological and evolutionary dynamics.For instance,level of genetic structure of populations provides important information about the role of genetics and gene ow in determining local patterns of selection on hosts due to parasitism(i.e.,egg rejection) and on parasites due to selection by hosts(i.e.,egg mimicry).Furthermore,abiotic(i.e.,climatic conditions) and biotic(phenotypic characteristics of animals) factors that also vary spatially may directly or indirectly a ect populations of hosts and brood parasites and,therefore,their interaction.By reviewing the literature,we found considerable evidence for an e ect of the spatially and temporally structured abiotic environment on the phenotype of both parasite and host eggs and the degree of mimicry.Moreover,we found examples suggesting that speci c life history characteristics of hosts that vary geographically and/or temporally may a ect the probability of initial colonization of a new host species and the direction and the speed of coevolution.We provide an exhaustive review of studies investigating temporal and spatial patterns of the interaction between brood parasites and their hosts.Such temporal and spatial trends in parasite and host traits are,together with genetic information on rejection and signi cant e ects of gene ow,consistent with coevolutionary dynamics.However,gene ow and changes in the temporal and spatial patterns of abundance of both parasites and hosts may result in frequent cases of counter-intuitive relationships between the phenotype of the parasite and that of the host(i.e.,poor or no mimicry),which may suggest limits to the degree of adaptation.We provide a list of scienti c questions in need of further investigation,concluding that studies of brood parasites and their hosts may play a central role in testing the geographic theory of coevolution and several alternative hypotheses.

Surface Plasmon Resonance Based Sensing of Different Chemical and Biological Samples Using Admittance Loci Method

The admittance loci method plays an important role in the design of multilayer thin film structures. In this paper, admittance loci method has been explored theoretically for sensing of various chemical and biological samples based on surface plasmon resonance （SPR） phenomenon. A dielectric multilayer structure consisting of a Boro silicate glass （BSG） substrate, calcium fluoride （CaF2） and zirconium dioxide （ZrO2） along with different dielectric layers has been investigated. Moreover, admittance loci as well as SPR curves of metal-dielectric multilayer structure consisting of the BSG prism, gold metal film and various dielectric samples have been simulated in MATLAB environment. To validate the proposed simulation results, calibration curves have also been provided.

Discovery of ferrocene-carborane derivatives as novel chemical antimicrobial agents against multidrug-resistant bacteria

Antimicrobial resistance has now become a very serious global public health problem. New drug discovery and development are urgently needed to combat the growing threat of multidrug-resistant (MDR) bacteria. The aim of this study was to explore the potential application of three ferrocene-carborane derivatives as new promising agents to confront the problem of increasing antibiotic resistance. The results of agar diffusion bioassay, minimal inhibitory concentrations (MIC) testing and time-kill assay illustrate their broad-spectrum antimicrobial activities to both American Type Culture Collection (ATCC) control strains and MDR clinical isolates. It is evident that the relevant antimicrobial properties are all in a dose-dependent manner and gradually transform into a bactericidal effect from a bacteriostatic effect with the increasing of the drug concentration. Furthermore, these ferrocene-carborane derivatives have no/little toxic effect on normal cells like HELF cells and lead to little hemolysis at their MICs. This raises the possibility to develop novel antimicrobial drugs using these new ferrocene carborane derivants.

A Batesian mimic and its model share color production mechanisms

Batesian mimics are harmless prey species that resemble dangerous ones （models）, and thus receive protection from predators. How such adaptive resemblances evolve is a classical problem in evolutionary biology. Mimicry is typically thought to be difficult to evolve, especially if the model and mimic produce the convergent phenotype through different proximate mecha- nisms. However, mimicry may evolve more readily if mimic and model share similar pathways for producing the convergent phenotype. In such cases, these pathways can be co-opted in ancestral mimic populations to produce high-fidelity mimicry with- out the need for major evolutionary innovations. Here, we show that a Batesian mimic, the scarlet kingsnake Larnpropeltis elap-soides, produces its coloration using the same physiological mechanisms as does its model, the eastern coral snake Micrurus fulvius. Therefore, precise color mimicry may have been able to evolve easily in this system. Generally, we know relatively little about the proximate mechanisms underlying mimicry .

Molecular strategies of plant defense and insect counter-defense

The prediction of human population growth worldwide indicates there will be a need to substantially increase food production in order to meet the demand on food supply.This can be achieved in part by the effective management of insect pests. Since plants have co-evolved with herbivorous insects for millions of years, they have developed an array of defense genes to protect themselves against a wide variety of chewing and sucking insects.Using these naturally-occurring genes via genetic engineering represents an environmentally friendly insect pest-control measure. Insects, however, have been actively evolving adaptive mechanisms to evade natural plant defenses. Such evolved adaptability undoubtedly has helped insects during the last century to rapidly overcome a great many humanimposed management practices and agents, including chemical insecticides and genetically engineered plants. Thus, better understanding of the molecular and genetic basis of plant defense and insect counter-defense mechanisms is imperative, not only from a basic science perspective, but also for biotechnology-based pest control practice. In this review, we emphasize the recent advance and understanding of molecular strategies of attack-counterattack and defense-counter-defense between plants and their herbivores.