OBJECTIVETo study the molecular action mechanism of active constituents desoxyrhaponticin (DES) and human serum albumin (HSA).

METHODUnder the simulated physiological condition, computer analog technology, fluorescent spectrometry and ultraviolet spectrum were combined to study the binding mechanism between drug and protein.

RESULTMolecular modeling was adopted to establish the binding model between DES and HSA, suggesting that the interaction force maintaining drug and protein is mainly the hydrophobic interaction with a hydrogen-bond interaction. The results from spectroscopy indicated that the interaction between DES and HSA is a dynamic binding process with a high intensity. The value of the binding distance (r) between DES and HSA was low, which demonstrate the occurrence of energy transfer. DES made an impact on HSA' structural domain microcell conformation, which resulted in hydrophobic changes in binding areas. According to the fluorescent phase diagram technical analysis, the changes in the DES-HSA reaction conformational pattern showed a "two-state" model. According to the obtained thermodynamic parameters for the DES-HSA interaction, the interactional force between DES and HSA was mainly a hydrophobic interaction. The fluorescence polarization proved that a non-covalent compound was generated during the interaction between DES and HSA.

CONCLUSIONThe spectrum experiment showed consistent results with the computer analog technology, which could provided certain reference for studies on the interaction between DES and HSA.

Humans ; Models, Molecular ; Protein Binding ; Protein Conformation ; Serum Albumin ; chemistry ; metabolism ; Spectrometry, Fluorescence ; Spectrophotometry, Ultraviolet ; Stilbenes ; metabolism ; Thermodynamics

The viability and life span of pollen were evaluated by TTC (2,3,5-triphenyl tetrazlium chloride) and the peroxidase solution, the stigma receptivity were estimated by benzidine-H2O2 method and the fruiting characteristics were investigated. The results showed that (1) Anoectochilus roxburghii and A. formosanus appeared the same up-and-down trend of the pollen viability, increased and then decreased. The storage temperature and storage time had significant impact on the pollen viability. With the extension of storage time, the pollen activity decreased. 4 degrees C refrigerator storage may be extended the pollen vitality. (2) The stigma had receptivity in 1st day and reached the highest level in the 4th day after blooming. A. roxburghii lost receptivity in the 8th day while A. formosanus lost receptivity in the 10th day after blooming. (3) The different pollination had significant impact on seed setting rate. The seed setting rate of artificial cross-pollination was higher than that of the artificial self-pollination. Collecting pollen in the 3rd day and carrying out artificial cross-pollination in the 4th day after blooming can significantly improve seed setting rate. The results provided technical assurance for A. roxburghii and A. formosanus breeding of new varieties and seed breeding.
Cell Survival ; China ; Flowers ; physiology ; Fruit ; growth & development ; Orchidaceae ; growth & development ; physiology ; Pollen ; growth & development ; Reproduction ; Temperature

Compared with living spray method, it focused on the investigation of different inoculation methods, various inoculation concentration and the influence of different seeding age on soft rot-resistance in Jinxianlian. The results showed that (1) Inoculated with dropping connection, the difference of disease index between A. roxburghii and A. formosanus was grate, so that the disease-resistance could be obviously distinguished. (2) When the inoculation concentration was 1.0 x 10(7) cfu x mL(-1), the difference of disease index was relatively obvious and the disease-resistance could be differentiated well. (3) At the moment of 4-month seeding inoculation, a certain difference of the disease index between A. roxburghii and A. formosanus was existed, so, relatively, it could accurately reflect the resistance difference between various species. With the inoculation of dropping connection, A. roxburghii and A. formosanus of 4-month seeding age was put in the bacteria suspension of inoculation concentration of 1.0 x 10(7) cfu x mL(-1). The identification was taken up after 5 days in the incubator under the condition of 14 h daylight and 28 degrees C. The identification result was conformed with that of the living spray method. To investigate the identification method of in vitro evaluation of soft rot-resistance of Jinxianlian so as to provide the foundation for germplasm utilization and excellent cultivars breeding.
Plant Diseases ; microbiology

The mycelium growth and sporulation in different temperature, pH value and light conditions were detected by using the crossing and haemocytometer method. The toxicity of five fungicides to Fusarium oxysporum was tested by mycelia growth method, so as to provide the reference for prevention and control against F. oxysporum. The optimum temperature and pH value of F. oxysporum to grow and spore were 28 degrees C and 6-7. Alternating light and darkness promoted growth and sporulation of bacterial colony. As for five fungicides, the EC50 of tebuconazole was 10.02 mg x L(-1), 92.50 times as much as carbendazim. The EC50 of myclobutanil and Fuxing was 91.23, 96.68 mg x L(-1), respectively. Tebuconazole showed the most tremendous inhibitory effect and control efficiency on F. oxysporum.
Fungicides, Industrial ; pharmacology ; Fusarium ; drug effects ; growth & development ; Mycelium ; drug effects ; growth & development ; Orchidaceae ; microbiology ; Plant Diseases ; microbiology ; Spores, Fungal ; drug effects ; growth & development

Nine morphologic traits, plant height, ground diameter, leaf length, leaf width, leaf area of plant, leaf fresh weight, blades, length/width ratio, plant fresh weight of Anoectochilus roxburghii from 13 different areas were determined for correlation analysis, path analysis and principal components analysis. Different source of morphological trait variation coefficient of A. roxburghii was 2.96% -12.59%, plant fresh weight was significant positively correlated with ground diameter, plant height and leaf number, and positively correlated with leaf fresh weight. Path analysis showed that plant height had the largest positive direct effect on plant fresh weight, the leaf fresh weight and blades number had indirect effects on the plant fresh weight. Through principal component analysis, morphological traits of A. roxburghii can be divided into "Determinants of high-yielding morphology" and "Determinants of leaf production". In the actual process of production and breeding of A. roxburghii, we should pay attention to plant height, leaf fresh weight, blades numbers and other traits.
China ; Orchidaceae ; anatomy & histology ; chemistry ; classification ; growth & development ; Phenotype ; Plant Leaves ; anatomy & histology ; chemistry ; growth & development

The morphological index of the seedlings including the plants height, the ground diameter, the leaf amounts, the fresh weight of the whole plant and the ratio of height to diameter was measured and the principal components were analyzed so as to determine the grading index, and stepwise cluster analysis was applied for clustering analysis. Pot experiments were used to measure the indicators of plant growth and development, the yield and the quality. The results showed that the height and ground diameter were determined as the quality indicators of the seedlings grading and the standard quality grading of seedlings of Anoectochilus roxburghii was initially set up, different seeding plants influenced the plants growth and the yield. The ground diameter of the class I was larger than that of the class II and III, so as the yield. The seedling grading had no obvious effect on the internal quality of medicinal materials. The results of the study provide the basis for standard cultivation of A. roxburghii.
Drugs, Chinese Herbal ; analysis ; Orchidaceae ; chemistry ; classification ; growth & development ; Quality Control ; Seedlings ; chemistry ; classification ; growth & development

The binding mechanism between pefloxacin mesylate (PM) and transferrin (Tf) was explored using spectral experiment combined with molecular modeling techniques. The binding parameters and thermodynamic functions of PM-Tf solution system were measured at different temperatures. The effect of PM on molecular conformation of Tf was investigated and the interaction mechanism was also discussed. The results showed that dynamic quenching mechanism occurs with PM binding to Tf. The value of binding distances (r) is low, which indicates the occurrence of energy transfer. The drug had conformational effect on Tf, which resulted in changes of hydrophobic environment of the binding domain in Tf. According to the obtained thermodynamic parameters, the main interaction force between PM and Tf is attributed to hydrophobic bonding. The results of molecular modeling revealed that hydrophobic and hydrogen bonds are main binding forces in the PM-Tf system. These results were in accordance with spectral experiments. The research results have given a better theoretical reference for the study of pharmacological mechanism between protein and quinolone.
Hydrophobic and Hydrophilic Interactions ; Models, Molecular ; Pefloxacin ; chemistry ; metabolism ; Protein Binding ; Protein Conformation ; Thermodynamics ; Transferrin ; chemistry ; metabolism