山楂和山楂叶中25种元素的含量

本文报导了用电感耦合等离子体发射光谱法测定山楂和山楂叶中25种元素的含量,并讨论其中某些元素与山楂、山楂叶的药效之间的关系。     

DVS乳酸菌种菌株传代过程中遗传稳定性分析

目的：对从直投式酸奶发酵剂中分离出的乳酸菌菌株传代过程中的遗传稳定性进行分析。方法：观察传代培养过程中各个菌株在转管不同次数时的形态变化,用RAPD方法分析传代过程中转管不同次数的乳酸菌基因组的变化趋势,并用SDSPAGE对比转管不同次数乳酸菌的蛋白质表达的差异。结果：乳球菌在传代过程中转管不同次数时基因组和蛋白质表达均无变化;乳杆菌1^#在传代过程中转管不同次数时基因组基本无变化,蛋白质表达有变化;乳杆菌2^#在传代过程中转管不同次数时基因组和蛋白质表达均有变化。结论：采用RAPD、SDS-PAGE方法可以有效地对直投式酸奶发酵剂菌株传代过程中的遗传稳定性进行分析。     

Sequence and genetic organization of the 19.3-kb erythromycin- and dalfopristin-resistance plasmid pLME300 from Lactobacillus fermentum ROT1

Lactobacillus fermentum ROT1 was isolated from a raw milk dairy product. It is resistant to novobiocin, tetracycline, erythromycin and dalfopristin. A chromosomal tetracycline-resistance determinant was identified as tetM. A 19,398-bp plasmid (pLME300), present in several erythromycin-resistant strains of Lb. fermentum, was isolated from strain ROT1 and completely sequenced. Based on putative open reading frames, pLME300 contains at least four different functional regions. In region I, ORF1 shows high homologies to replication proteins of different theta-replicating plasmids. In addition, a tandem repeat of a 22-bp sequence appears 4.5 times. In region II, ORF3 may code for a methylase, and ORF4 has homologies to Mrr restriction system proteins of Deinococcus radiodurans and Escherichia coli suggesting a restriction-modification system. Region III harbours antibiotic-resistance genes, coding for a macrolide-lincosamide-streptogramin B (MLS) methylase Erm(LF) and the streptogramin A acetyltransferase Vat(E), which is identical to Vat(E) from Enterococcus faecium. Furthermore, region III shows a 91% nucleotide sequence identity to an erm-vat linkage of E. faecium. Region IV carries ORFs that appear to be involved in plasmid mobilization as characterized by a putative origin of transfer and a mobilization protein. pLME300 is the largest completely sequenced multi-resistance plasmid isolated from any Lactobacillus strain so far.     

Response of the melon aphid, Aphis gossypii, to host-plant resistance: evidence for high adaptive potential despite low genetic variability

In agrosystems, pests are submitted to strong human-imposed selective pressures to which they sometimes adapt rapidly, either through selection of genotypes resulting from mutation and/or recombination events, or through phenotypic plasticity. Understanding how insects respond to such selective pressures is of great importance for sustainable pest management strategies, such as the use of resistant plants. In this study, we investigated the genetic and phenotypic variability of anholocyclic Aphis gossypii Glover (Hemiptera: Aphididae) strains, in response to the resistance gene Vat that is present in melon crops. Forty-nine aphid colonies were sampled on several melon crops in southern France, genotyped using 15 microsatellite loci, and tested in phenotypic experiments using Vat or non- Vat melons. The level of genetic polymorphism between these colonies was low, as only seven multilocus genotypes were detected. In contrast, the phenotypic variability for life-history and behavioral traits between colonies, including those sharing the same genotype, was unexpectedly high, with a continuum of response to the Vat gene from complete susceptibility to strong virulence. The low genetic polymorphism associated with a strong phenotypic variability highlights the high adaptive potential of A. gossypii and the major role of environmental cues in shaping phenotypic responses of this aphid to pest management strategies.     

Application of germinated maize starch in textile printing

Germinated maize is generally discarded as a waste material. In the present investigation starch obtained from germinated maize has been compared with the starch from non-germinated maize, as a thickener in textile printing. Extraction of starch was done by alkali steeping method. Analysis of both the starches was done by measuring swelling power, paste clarity, particle size, crystallinity and iodine binding. Printing of vat dyes on 100% cotton fabric was carried out using both the starches. The prints were analysed by measuring colour value (K/S and L^*, a^*, b^* value), bending length and fastness to washing and crocking. Results suggest that germinated maize starch can substitute the non-germinated maize starch partially if not fully, as a thickener in printing.     

An approach for vat color printing on cotton and polyester fabrics with electron beam irradiation curable formulations

Accelerated electrons delivered by electron beam accelerator were used to fix vat colors, incorporated in curable formulations containing diluting monomer and an oligomer, to cellulosic fabric, cotton and polyester fabric. Tetrahydrofurfuryl acrylate, hexane dioldiacrylate, monomers and trifunctional urethane methacrylate, oligomer were used as curable base beside ethylene glycol. The fabrics were printed with these formulations and exposed to various doses of electron beam irradiation generated from the 1.5 MeV (25 kW) electron beam accelerator machine. Critical factors included the irradiation dose, formulation composition, and vat color concentration were studied. The fabrics printed with the vat colors by electron beam irradiation displayed higher color yield than those fabrics printed by the conventional curing at equal vat color ratios. The durable properties of fabrics printed by electron beam irradiation except the roughness properties are extremely better than those printed by conventional fixation method.