数学建模在生物化感及其赫米西斯(Hormesis)现象中的应用

简述了国内外对生物化感数学建模的研究近况,包括通过数学模型描述化感物质的赫米西斯(Hormesis)现象,化感作用在受体植物不同密度条件下的表达,植物残茬中化感物质的分解动态及受体植物的动态响应,环境中化感物质的动态变化规律及在植物-昆虫-天敌系统中的应用等。并对化感数学建模领域的先驱机理模型An-Hormesis模型,An-Liu-Johnson-Lovett模型,和An_Residue模型做了简介。

Determination of the Antioxidant Capacity of Different Types of Bread and Flour Using a Superoxide Dismutase Biosensor

The aim was to experimentally evaluate the antioxidant capacity of different types of bread and of the relative flour used for bread production utilizing a superoxide dismutase （SOD） biosensor recently developed by the present authors. Measurements were carried out by comparing the biosensor response to the concentration of superoxide radical produced in solution using a xanthine/xanthine oxidase system in the presence and in the absence of the antioxidant sample considered, respectively. Precision of antioxidant capacity measures for crust and crumb of the different breads was found to be good （RS D% ≤ 8%） and acceptable for the watery suspension and filtrate of the different flours studied （RSD% ≤ 12%）. The obtained results indicated that general flours show higher antioxidant capacity values than the corresponding breads and that crusts show always an antioxidant capacity definitely larger than the crumb. Lastly, the antioxidant capacity values were compared with those of almond, red pepper and strawberry, three foods containing powerful natural antioxidants.

New amperometric glucose biosensor by entrapping glucose oxidase into chitosan/nanoporous ZrO_2/multiwalled carbon nanotubes nanocomposite film

A new nanocomposite material for construction of glucose biosensor was prepared. The biosensor was formed by entrapping glucose oxidase(Gox) into chitosan/nanoporous ZrO2/multiwalled carbon nanotubes nanocomposite film. In this biosensing thin film, the multiwalled carbon nanotubes can effectively catalyze hydrogen peroxide and nanoporous ZrO2 can enhance the stability of the immobilized enzyme. The resulting biosensor provides a very effective matrix for the immobilization of glucose oxidase and exhibits a wide linear response range from 8 μmol/L to 3 mmol/L with a correlation coefficient of 0.994 for the detection of glucose. And the response time and detection limit of the biosensor are determined to be 6 s and 3.5 μmol/L, respectively. Another attractive characteristic is that the biosensor is inexpensive, stable and reliable.

Scoping biology-inspired chemical engineering

Biology is a rich source of great ideas that can inspire us to find successful ways to solve the challenging problems in engineering practices including those in the chemical industry. Bio-inspired chemical engineering(Bio Ch E)may be recognized as a significant branch of chemical engineering. It may consist of, but not limited to, the following three aspects: 1) Chemical engineering principles and unit operations in biological systems; 2) Process engineering principles for producing existing or developing new chemical products through living ‘devices';and 3) Chemical engineering processes and equipment that are designed and constructed through mimicking(does not have to reproduce one hundred percent) the biological systems including their physical–chemical and mechanical structures to deliver uniquely beneficial performances. This may also include the bio-inspired sensors for process monitoring. In this paper, the above aspects are defined and discussed which establishes the scope of BioChE.

Allelopathic Potentials of Some Crop Residues on the Germination and Seedling Growth of Chromolaena Odoratum L.

The allelopathic effects of aqueous extracts of rice husk （Orza sativa L.） and sorghum stem （Sorghum bicolor L.） on the germination and seedling growth of Chromolaena odoratum L. were investigated. The extracts of the two crop residues exhibited inhibitory effects on the germination and seedling growth of Chromolaena odoratum L. The degree of retardation demonstrated in both extracts was concentration dependent. However the results obtained revealed that the retardation was more pronounced in the rice husk extract-treated seeds. However statistical analysis （P 〈 0.05% level） revealed that the degrees of inhibition of radicle and plumule obtained from various extracts treated seeds of both extracts were not significantly different when compared to those obtained from the control experiments as well as those obtained from the varying extract concentrations.

Fiber optic biosensor of immobilized firefly luciferase

Luciferase from firefly lantern extract was immobilized on CNBr activated Sepharose 4B. The kinetic properties of immobilized luciferase were extensively studied. The K m′ for D luciferin is 11.9 μmol/L, the optimum pH and temperature for Sepharose bound enzyme were 7.8 and 25℃ respectively. A luminescence fiber optic biosensor, making use of immobilized crude luciferase, was developed for assay of ATP. The peak light intensity was linear with respect to ATP concentration in range of 10 -9 -10 -5 mol/L. A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal oxygen environments.

Polyaniline-graphite composite film glucose oxidase electrode

A novel polyaniline-graphite composite film glucose oxidase （PGCF GOD） electrode was developed. The PGCF was synthesized by cyclic voitammetry method in 0.5 mol/L H2SO4 solution containing 1 g/L graphite powder and 0.2 mol/L aniline. The PGCF GOD electrode was prepared by doping GOD into the composite film. The morphology of the PGCF and the response property of the PGCF GOD electrode were investigated by scanning electron microscopy and electrochemical measurement, respectively. The results show that the PGCF has a porous and netty structure and the PGCF GOD electrode has excellent response property such as high sensitivity and short response time. Influences of pH value, temperature, glucose concentration and potential on the response current of the electrode were also discussed. The sensor has a maximum steady-state current density of 357.17μA/cm2 and an apparent Michaelis-Menten constant of 16.57 mmol/L. The maximum current response of the enzyme electrode occurs under the condition ofpH 5.5, 0.8 V and 65℃.

Interspecific competition and allelopathic interaction between Karenia mikimotoi and Dunaliella salina in laboratory culture

Algal allelopathy is a manifold ecological/physiological phenomenon that is focused on chemical interactions and autotoxicity. We investigated the allelopathic interactions between Karenia mikimotoi and Dunaliella salina in laboratory cultures based on different temperature （15℃, 20℃, and 25℃） and lighting （40,80, and 160 umol/（m2·s）） conditions. The growth of D. salina in bi-algae culture （1：1 size/density） was significantly restrained. The results of cell-free filtrate culture indicate that direct cell-to- cell contact was not necessary in interspecific competition. Further experimental results demonstrated that allelochemicals released from K. miMmotoi were markedly influenced by both temperature （P=0.013） and irradiance （P=0.003）, resulting in different growth characteristics olD. salina in filtrate mediums. Compared with the plateau period, K. mikimotoi exudates in the exponential phase had a stronger short-term inhibition effect on D. salina in normal conditions. A clear concentration-dependent relationship was observed in the effect of allelochemicals released from K. mikimotoi with low-promoting and high-repressing effects on D. Salina in a short time-scale. In addition, allelopathic substances remain stable and effective under high temperature and pressure stress. Many flocculent sediments adhering with D. salina cells were observed in all filtrate mediums, while the quantity and color depended on the original culture conditions.

Remote sensing Extraction model of redtide biomass by airborne hyperspectral technique

Our work is based on the known research results of inherent optical quality of ocean color constituents.According to optimized parameters and induced fluorescence term of chlorophyll, this paper puts forward a remote sensing reflectance model of sea water, which is fitted in Liaodong Bay of Bohai. An inverse model that can evaluate redtide biomass according to chlorophyll retrieval is provided by inducing a functional extreme problem. The calculation example of the model indicates that the inversion model has explicit mathematic and physical meaning, but its practicability needs to be verified.

Laccase biosensor using magnetic multiwalled carbon nanotubes and chitosan/silica hybrid membrane modified magnetic carbon paste electrode

A simple and rapid strategy to construct laccase biosensor for determination of catechol was investigated. Magnetic multiwalled carbon nanotubes (MMCNT) which possess excellent capability of electron transfer were prepared by chemical coprecipitation method. Scanning electron microscope (SEM) and vibrating sample magnetometer (VSM) were used to identify its surfacetopography and magnetization, respectively. Laccase was immobilized on the MMCNT modified magnetic carbon paste electrode by the aid of chitosan/silica (CS) hybrid membrane. Using current-time detection method, the biosensor shows a linear response related to the concentration of catechol in the range from 10-7 to 0.165×10-3 mol/L. The corresponding detection limit is 3.34×10-8 mol/L based on signal-to-noise ratios (S/N) ≥3 under the optimized conditions. In addition, its response current retains 90% of the original after being stored for 45 d. The results indicate that this proposed strategy can be expected to develop other enzyme-based biosensors.

Allelopathic Potentials of Some Crop Residues on the Germination and Growth of Bidens pilosa. L.

The allelopathic potentials of the aqueous extracts of rice husk and sorghum stem were examined on the germination and growth ofBidens pilosa. L. The extracts inhibited the germination ofB. pilosa seeds and the growth lengths of its radicle and plumule. In both extracts, the severity of the inhibition increased with the increase in the concentrations of the extracts, indicating that the effects of the extracts were concentration dependent. The results obtained also showed that the degree of retardation appeared to be more pronounced in the rice husks extract-treated seeds than those of sorghum extract-treated seeds. However there were no significant differences （at 5% level） in the comparison of the degree of inhibitions of radicle and plumule growths at the varying extract concentrations as well as those of the control in both extracts treated seeds.

The Process of Immobilization of ZnO Nanorods Surface with Galactose Oxidase

ZnO nanorods, with the c-axis orientation used for transparent conductors, solar cells, sensors especially the functionalized ZnO nanorods with some kinds of enzymes have been used for biosensor. In this work, we describe the process immobilization of galactose oxidase on ZnO nanorods surface with glutaraldehyde as a cross-linker molecule to make the working electrode in electrochemical biosensor. ZnO nanorods were grown on FTO （Fluorine-doped tin oxide） substrate by solution method at low temperature. The crystalline phase and orientation of ZnO nanorods were identified using X-ray diffraction. The efficiency of the immobilization was calculated by Braford method showed that about 36% enzyme content was immobilized on ZnO nanorods surface. The working electrode based on the immobilized ZnO nanorods was tested in galactose solution by CV （cyclic voltammetry） method indicated the value of current intensity is about 0.14 μA. These results clearly demonstrate the potential of galactose sensor based on ZnO nanorod.

Simulation of CO_2 and sensible/latent heat fluxes exchange between land surface and atmosphere over cropland and grassland in semi-arid region,China

A comparison between simulated land surface fluxes and observed eddy covariance （EC） measurements was conducted to validate Integrated Biosphere Simulator （IBIS） at Tongyu field observation station （44°25＇N, 122°52＇E） in Jilin Province, China. Results showed that the IBIS model could reproduce net ecosystem CO2 exchange （NEE）, sensible and latent heat fluxes reasonably, as indicated by correlation coefficients exceeding the significant level of 0.05. It was also evident that the NEE and sensible heat fluxes were characterized by diurnal and seasonal variation both in the grassland and the cropland ecosystems, while the latent heat fluxes correlated with evapotranspiration, only took on the diurnal variation during the growing season. Moreover, both sensible heat fluxes and the latent heat fluxes were larger in the cropland ecosystem than that in the degraded grassland ecosystem. This different characteristic was possibly correlated with vegetation growing situation in the two kinds of ecosystems. A close agreement between observation and simulation on NEE, sensible heat fluxes and latent heat flux was obtained both in the degraded grassland and the cropland ecosystems. In addition, the annual NEE in the model was overestimated by 23.21% at the grassland and 27.43% at the cropland, sensible heat flux with corresponding 9.90% and 11.98%, respectively, and the annual latent heat flux was underestimated by 4.63% and 3.48%, respectively.

Allelopathic Effects of Eichhornia crassipes on the Growth of Microcystis aeruginosa

Algal blooms caused by eutrophication in fresh water are one of the major environmental problems in the world. Using biological methods to control algal growth, especially based on allelopathic inhibitory effects of aquatic macrophytes on phytoplankton growth, have been received world-wide attention. In this study, the allelopathic activity of the invasive macrophyte, Eichhornia crassipes （water hyacinth）, on blue-green algae, Microcystis aeruginosa （PCC7806） was investigated using coexistence assay. Our results showed that water hyacinth had disparate effects on the growth ofM~ aeruginosa （PCC7806） under different initial algal densities. Under lower initial algal density （OD650 = 0.10 and OD650 = 0.05）, the algal growth was significantly inhibited by water hyacinth （inhibition ratio was 95.6% and 97.3%, respectively）. While it was stimulated at higher initial algal densities （OD650 = 0.20）. Water hyacinth inhibited the growth of algae mainly through its root system. Culture water from water hyacinth and aqueous methanol extracts from dry roots samples also showed inhibition effects on algal growth. The inhibition effects increased as the increase of crude extract concentration, suggest that water hyacinth may excrete inhibitory substances from root system and show allelopathic inhibitory potential to the growth ofM. aeruginosa.

A Novel 3-D Nano-assembly Bacteria Based Biosensor for Enhanced Detection of Heavy Metal Pollutants

Nowadays, at a time of growing concern for sustainable development and compliance with environmental standards and legislation, the detection of heavy metal contaminants in environmental matrices represents a difficult but important task. The current major limitation lies in the poor detection limits of the targeted pollutant＇s trace concentrations by the available conventional techniques. In order to elaborate a novel ＂living＂ self assembled electrochemical 3-D biosensor, the authors propose a new concept to overcome this shortcoming. The advantages of the properties of polyelectrolyte-functionalized NBs （nanobeads） are combined along with the use of non covalently strongly bound micro-organisms. The designed 3-D biosensor is all the more promising as it has showed a significantly improved sensitivity. In fact, the detection limits of the tested heavy metals （cadmium and mercury） were as low as 1.0 × 10^-12 mol.L-1 and six to seven orders of magnitude lower than those provided by conventional 2-D biosensors. Furthermore, it is potentially applicable to a wide range of bioreceptor-pollutant detection systems.

Electrochemical biosensors and logic devices based on aptamers

Aptamers are molecular recognition elements with high specificity that are selected from deoxyribonucleic acid/ribonucleic acid (DNA/RNA) library. Compared with the traditional protein recognition elements,aptamers have excellent properties such as cost-effective,stable,easy for synthesis and modification. In recent years,electrochemistry plays an important role in biosensor field because of its high sensitivity,high stability, fast response and easy miniaturization. Through the combination of these two technologies and our rational design,we constructed a series of biosensors and biochips that are simple,fast,cheap and miniaturized. Firstly,we designed an adenosine triphosphate (ATP) electrochemical biosensor based on the strand displacement strategy. We can detect as low as 10 nmol/L of ATP both in pure solution and complicated cell lysates. Secondly,we creatively split the aptamers into two fragments and constructed the sandwich assay platform only based on single aptamer sequence. We successfully transferred this design on biochips with multiple micro electrodes (6×6) and accomplished multiplex detection. In the fields of biochips and biocomputers,we designed several DNA logic gates with electric (electrochemical) signal as output which paves a new way for the development of DNA computer.

Perspectives in application of biosensors for the modernization of traditional Chinese medicine

Biosensor is an instrument which is sensitive to biological material and converts its concentration into electrical signals.Organisms such as enzymes, antibodies, tissues, cells and so on can selectively identify specific substances. Thesemolecular recognition functions can be combined with the target, such as the binding of antibodies and antigens, and thebinding of enzymes to the substrate through the recognition process. Biosensor has the advantages of high specificity,high sensitivity, fast reaction speed, low cost and easy operation. It has wide application prospect in food, pharmacy,chemical industry, clinical examination, biomedicine, environmental monitoring and so on, especially as a newtechnology means, in the field of modern herbal medicine research influence. Studies have demonstrated that thebiosensing technology has been applied to, traditional Chinese medicine （TCM） targets, isolation and purification ofTCM, the mechanism of TCM, quality control of TCM, the active ingredients detection of TCM and other basicresearches. Biosensor technology has made an important contribution to the research of modern herbal medicine, and hasbecome a Hot-spot in future research.

Allelopathic Effect of Achillea （Achillea santolina） on Germination and Growth of Crop Plants

In order to investigate the likely allelopathic potential of an aqueous extract and powder of Achillea （,4chillea santolina） on the germination and seedling growth of pea （Cicer arietinum）, safflower （Carthamus tinctorius L.） and wheat （Triticum sativum）, an experiment was carried out at the laboratory and greenhouse of agriculture faculty of Sho3hid Bahonar University of Kerman, Iran, from October 2009 to March 2010. A completely randomized design with three replicates using five extract concentrations of achillea plant including 0, 25, 50, 75, and 100 g Ll and four amounts of powder of it including 0, 7.5, 15 and 30 g kg1 of soil was employed in laboratory and greenhouse experiments, respectively. All extract concentrations of achillea except 25 g Ll inhibited pea and wheat seed germination significantly, but had no inhibitory effect on the germination of safflower, The powder of mature achillea plants affected the fresh and dry weight and shoots length in these crops negatively compared with the control in all levels. Therefore use of this plant should be prevented in rotation or intercropping with these three crop plants. Further research conducted in the analytical laboratory as well as in the field is needed before a practical application of the extract and powder as weed inhibiting agent can be recommended.

Management of Chenopodium album L. through the Allelopathic Effect of Mangifera indica L.

Chenopodium album is an invasive weed in wheat fields in Egypt. The present study indicated the potentials for utilization of MILAE （Mangifera indica leaves aqueous extract） at different concentrations （5%, 10%, 15% and 25%） to suppress the germination and growth of C. album in Petri dish experiment Results indicated that predictable degrees of inhibition in C album germination and growth rate of seedlings were accompanied with the increase in the concentration of MILAE. PL （Plumule） and RL （radicle） lengths of C. album were negatively affected as the concentration of MILAE increased and the effect was prominent at 25% extract concentration. This study recommended the use of MILAE as strong phytotoxic potential allelochemicals. an alternative bioherbicides, since its leaves extract possess

The Post-exposure Effects of Spinosad and Plant Allelochemicals on Biological Characteristics of Helicoverpa armigera(Lepidoptera： Noctuvidae)

In order to define the combined effects of spinosad and plant allelochemicals on Helicoverpa armigera(Lepidoptera:Noctuvidae), the research fed them on artificial diets with different doses of spinosad, gossypol, quercetin and tannicacid, and the changes of pupal and imaginal biological characteristics were observed and recorded. The results showed that spinosad at sublethal concentrations decreased pupation ratio and pupal weight, prolonged prepupal and pupal periods, and decreased emergence ratio, fecundity and longevity of adults. Combined with plant allelochemicals, spinosad significantly prolonged pupal period and shorten adult longevity. Other life-cycle parameters such as pupation ratio, pupal weights, emergence ratio, eggs laid per female and hatch ratio did not change significantly. The results clearly indicated that plant allelochemicals did not change spinosad efficiency on H. armigera, but the combination of spinosad and plant allelochemicals might affect pest population dynamics significantly by changing its development.