Advanced Materials Research Vols. 634-638

Abstract: Objective To research antibacterial activity of Limonium aureum endophytic fungi. Methods The endophytic fungi of Limonium aureum root was isolated by general method. After incubation, fermentation broth and biomass were extracted by ethyl acetate, n-bothanol and ethanol. The bactefiostatic test was experimented with six different bacterium．The method used was filter paper slice tests. Results 21 endophytes were obtained. After bactefiostatic testing, there were 31 samples with antibaceterial activity against at least one test bacterium he MIC of extraction from E101 and E201 against test bacteria was 0.25mg/mL.

Abstract: The generation of an engineering strain with reduced genome relies on efficient methods for marker-free gene knockout. In this study, research on the efficiency of deletion of genome fragments with upp-based counterselective method in Bacillus subtilis was carried out. Using this method, the 3.053 Kb, 12.414 Kb and 34.148 Kb fragments of the skin element were marker-free deleted successfully, with the efficiency of 27%, 11.4% and 25%, respectively. Here we demonstrate that this method is an efficient genetic tool for large genome fragments marker-free deletion.

Abstract: Straw resource was tremendous, however it was utilized poorly. So the research of physical, chemical and mechanical pulping properties of tobacco stalk fiber laid the foundation for utilization of tobacco stalk. Morphology of tobacco stalk fiber was determined by Feica microscope, the length, width and length to wide ratio were analyzed by SPSS 17.0. Chemical composition changes of tobacco stalk fiber after mechanical process were analyzed by applying Block test method with Design-expert 6.0.10.The result present that composition of fiber had significant difference. Hemi-cellulose increased by 3.24%, cellulose increased by 9.62%, lignin increased by 2.52%. Beating degree was positively correlated with the pulping time, beating time and wet weight were a negative correlation. Strength of tobacco stalk fiber was positively with the gramme, and strength was 17 N when gramme was 60 g/m2.

Abstract: The dissolution enthalpy of Cisplatin and Etoposide in the appropriate solvent were measured by RD496-2000 microcalorimeter under the conditions of atmospheric pressure and 309.65 K. The differential heat and the integral heat of the process are obtained, thereby establishing the relationship between the heat and the amount of solute, knowing that the dissolution process is the pseudo-first order reaction. In turn, the half-life, △solHm, △solGm, △solSm are also can obtained.

Abstract: The abamectin was microencapsulated with interfacial polymerization. The bursa wall materials of Abamectin microcapsule used in the experiment was polyurea which was produced by Tolylene-2,4-diisocyanate (TDI) and hexamethylenetetramine. The stirring speed and the dosage of emulsifier were determined by preliminary experiments, and the technical conditions for abamectin microencapsulation were optimized by orthogonal experiment, meanwhile, the optimal proportion and dosage of bursa wall materials, solvent and dispersant were determined. Encapsulation efficiency was measured by UV spectrophotometer. Results show that the encapsulation efficiency of microcapsules obtained is up to 90%.

Abstract: (s)-3-(t-butyldimethylsilyloxy)-7,7-dichloro-2,2-dimethyloctanoic acid (9), a segment of the new cyclodepsipeptide lyngbyabellin A[1] (14) , which exhibits moderate cytotoxycity against human cancer cell lines, was synthesized through six steps. The key stereoselective synthesis of (9) was achieved by the enantioselective aldol reaction developed by Kiyooka[2].

Abstract: 2-(1-tert-Butoxycarbonylamino-2-methyl-butyl)-thiazole-4-carboxylic acid methyl ester, the chiral unit containing thiazole of a novel cyclic depsipeptide Lyngbyabellin A which exhibited moderate cytotoxicity against KB and LoVo cells, was synthesized from N-t-Boc-L-isoleucine and L-serrine methyl ester monohydrochloride in overall yield 15% through six steps, including condensation, TBS protection, thionation, deprotection, cyclodehydration and aromatization. The ee value of the title chiral thiazole unit is up to 98％.

Abstract: Pitipeptolide A can be disconnected across the amide bind to afford t-Boc-glycine, the linear depsipeptide and the Dhoya fragment. 2,2-dimethyl-3-hydroxy-7-octynoic acid unit was prepared in eight steps from 1,5-pentanediol monobenzyl ether. including oxidation, TBS protection, deprotection and Saponification with (1M) sodium hydroxide solution gave the Dhoya unit (8) in 75% overall yield.

Abstract: The hindered N-methyldipeptide (N-Ns-N(Me)-L-Ala-N(Me)-L-Ile-OtBu), a segment of the new cyclodepsipeptide Apratoxin A^[1] , which exhibit cytotoxycity against human tumor cell lines, was synthesized from L-Alanine and L-iso-Leucine through ten steps in overall yield of 49.4%.

Abstract: Six β-diketo derivatives of mono-substituted calix[4]arene were synthesized as potential HIV-1 integrase inhibitors and evaluated their inhibition to the strand transfer process of HIV-1 integrase. Their structures were characterized by NMR and HRMS. All the title compounds as potential HIV-1 integrase inhibitors proved to be active in the micromolar range (6.7–37.6 μM) on the strand transfer step.