从替母到弑母——《金锁记》与《钢琴教师》中的母女关系比较

《金锁记》与《钢琴教师》两部小说里的母女关系跟传统的母女关系大相径庭,不再是温情脉脉,而是母亲压迫与女儿压抑的异化关系。同样是反抗,《金锁记》里的长安体现出了替母的倾向,而《钢琴教师》中的埃里克则有弑母的考虑。

Construction of recombinant industrial Saccharomyces cerevisiae strain with bglS gene insertion into PEP4 locus by homologous recombination

The bglS gene encoding endo-1,3-1,4-β-glucanase from Bacillus subtil＆ was cloned and sequenced in this study. The bglS expression cassette, including PGK1 promoter, bglS gene fused to the signal sequence of the yeast mating pheromone a-factor （MFals）, and ADH1 terminator with G418-resistance as the selected marker, was constructed. Then one of the PEP4 allele of Saccharomyces cerevisiae WZ65 strain was replaced by bglS expression cassette using chromosomal integration of polymerase chain reaction （PCR）-mediated homologous recombination, and the bglS gene was expressed simultaneously. The recombinant strain S. cerevisiae （SC-βG） was preliminarily screened by the clearing hydrolysis zone formed after the barley β-glucan was hydrolyzed in the plate and no proteinase A （PrA） activity was measured in fermenting liquor. The results of PCR analysis of genome DNA showed that one of the PEP4 allele had been replaced and bglS gene had been inserted into the locus of PEP4 gene in recombinant strains. Different endo-1,3-1,4-β-glucanase assay methods showed that the recombinant strain SC-βG had high endo-1,3-1,4-β-glucanase expression level with the maximum of 69.3 U/（h·ml） after 60 h of incubation. Meanwhile, the Congo Red method was suitable for the determination of endo-1,3-1,4-β-glucanase activity during the actual brewing process. The current research implies that the constructed yeast strain could be utilized to improve the industrial brewing property of beer.

An Ecological Alternative for the Control of Gastrointestinal Nematodes in Sheep in Northern Veracruz （Mexico）

The objective was to evaluate the effect of aqueous infusion of cracked soursop seeds on two different concentrations as an organic dewormer compared to a commercial one in GNE （gastrointestinal nematodes） egg population in crossbred hair sheep （Blackbelly-Khatadin） of the northen region of Veracruz. The aqueous infusion was prepared adding 93.5 g of cracked soursop seeds in 1,875 mL of boiled water and let stand for 12 h. Crossbred ewes were randomly assigned to receive every 19 days： （1） 10 mL of cracked soursop infusion orally （n = 27）, （2） 15 mL of cracked soursop infusion orally （n = 27）, and （3） 2 mL of Febendazole subcutaneously （n = 26）. Feces （2-5 g） were collected directly from the rectum of each animal on the following days： 0, 19, 38 and 57 days post treatment. Nematode egg population was determined using the technique of McMaster. Statistical analysis was done using ANOVA （analysis of variance）. There was a reduction overtime （P = 0.05） in all treatments in parasite egg population. There were no differences （P = 0.10） in egg population across treatments. In conclusion, aqueous infusion of soursop cracked seeds proved to be an environmentally friendly and effective alternative in the control of gastrointestinal parasites in crossbred hair sheep in the region of northern Veracruz.

Cloning, Expression and Characterization of a Lipase Gene from Marine Bacterium Pseudoalteromonas lipolytica SCSIO 04301

Absract A lipase gene, 1ip1233, isolated from Pseudoalteromonas lipolytica SCSIO 04301, was cloned and expressed in E. coli. The enzyme comprised 810 amino acid residues with a deduced molecular weight of 80kDa. Lip1233 was grouped into the lipase family X because it contained a highly conserved motif GHSLG. The recombinant enzyme was purified with Ni-NTA affinity chro- matography. The optimal temperature and pH value of Lip1233 were 45 ℃ and 8.0, respectively. It retained more than 70% of origi- nal activity after being incubated in pH ranging from 6.0 to 9.5 for 30min. It was stable when the temperature was below 45℃, but was unstable when the temperature was above 55℃. Most metal ions tested had no significant effect on the activity of Lip1233. Lip1233 remained more than original activity in some organic solvents at the concentration of 30% （v/v）. It retained more than 30% activity after incubated in pure organic solvents for 12 h, while in hexane the activity was nearly 100%. Additionally, Lip 1233 exhib- ited typical halotolerant characteristic as it was active under 4M NaC1. Lip1233 powder could catalyze efficiently the synthesis of fructose esters in hexane at 400C. These characteristics demonstrated that Lip1233 is applicable to elaborate food processing and organic synthesis.

Preparation of Organic Selenocystine Using Locally Isolated Bread Yeast

In contrast to the toxic inorganic forms of selenium to life at very low concentrations, the organic-selenium compounds are of considerable interest and several of them play essential roles in cell biochemistry and nutritional science. Se-yeast （Selenium-enriched yeast） is a common form of selenium used to supplement dietary intake of this important trace mineral. In the present study, we tried to prepare an organic selenocystine using locally isolated bread yeast （Saccharomyces cerevisiae）. A novel locally prepared date extract media enriched by addition of 0.2% KH2PO4 （potassium phosphate）, 0.6% ammonium sulfate was adopted as alternative culture media. Differences concentrations of selenium salt （30, 60, 120 and 240 lag/mL） were added to the yeast culture media. While the best concentration of selenium added was 30Bg/mL, it achieved optimal conditions for the growth of yeast and the production of red yeast growth identical to the standard. The products （organic selenocystine） were analyzed by HPLC （High Performance Liquid Chromatography） and AAS （Atomic Absorption Spectrophotometer） comparing with authentic standard obtained from Sigma. Results confirmed the formation of similar selenocystine products.