A single point mutation in the yeast TRP4 gene affects efficiency of mRNA 3' end processing and alters selection of the poly(A) site

The yeast TRP4 mRNA 3' end formation element is a bidirectional element which functions in both orien-tations in an artificial in vivo test system. In this study, the role of 3' end formation was analysed in the context of the entire TRP4 gene. The 3' untranslated region (3'UTR) of TRP4 was altered and changes were analysed for their influence on TRP4 gene expression. The 3'UTR in reverse orientation was fully functional and did not affect TRP4 gene expression. Exchanging the TRP4 3'UTR by the bidirectional ARO4 or the unidirectional GCN4 3' end formation element allowed efficient gene expression. Deletion of the entire TRP4 3'UTR resulted in 70% reduction of TRP4 mRNA and 50% reduced specific Trp4 enzyme activity in comparison to wild-type. A single point mutation within the TRP4 3'UTR caused the same effect on gene expression. This point mutation did not only affect the efficiency of 3' end formation, but also produced new poly(A) sites which were situated upstream of the wild-type poly(A) sites. Therefore this sequence motif in the TRP4 3'UTR acts simultaneously as both an efficiency and positioning element.     

Effects of humorous heroes and villains in violent action films

This experimental investigation explores the use of humor in violent action films, focusing on the effects of wisecracking heroes and villains on audience distress. An action film was edited to create control film versions without wisecracking dialogue. The research revealed contrast effects. Among female viewers, hero wisecracks in an action film increased distress reactions to the film, but lessened distressful reactions to subsequent televised depictions of real, nonhumorous violence. Conversely, males exposed to hero humor found the film marginally less distressing, but rated depictions of real violence more distressing. For all viewers, effects of villain wisecracks tended to parallel females' reactions to hero wisecracks. Disposition theory is offered as a plausible explanations of study findings.     

Allelotype influence at glutathione S-transferase M1 locus on breast cancer susceptibility

PURPOSE: To compare development of visual acuity and binocular vision in preterm and full-term infants in a prospective study that used testers masked to subject's gestational age. METHODS: Seventy-nine healthy full-term infants, mean gestational age 40 weeks, and 18 low-risk preterm infants, mean gestational age 33 weeks, were examined biweekly between the 44th and 54th weeks of postmenstrual age. Ocular alignment, convergence, fusion, grating acuity, and onset of optokinetic nystagmus (OKN) were assessed at each examination. RESULTS: The mean postnatal ages of onset of ocular alignment, convergence, fusion, grating acuity to 1.6 cycles per degree, and OKN from temporal to nasal and nasal to temporal were, respectively, 5, 7, 7, 11, 6, and 9 weeks for the full-term and 12, 13, 14, 18, 13, and 16 weeks for the preterm infants. The mean postmenstrual ages of onset for the corresponding parameters were 46, 48, 48, 51, 46, and 50 weeks for full-term and 46, 47, 48, 52, 47, and 49 weeks for preterm infants. The onset of all parameters was earlier in full-term infants than in preterm infants of the same postnatal age (P < or = 0.0001). However, no differences were found when the parameters were compared at postmenstrual ages. CONCLUSIONS: Additional visual experience of preterm infants does not influence development of visual acuity or binocular vision during the first months of life as measured from the time of conception.     

Fractionation studies of palm oil by density gradient

The paper describes a method of fractionating vegetable, animal and fish oils, and in particular palm oil. The method involves addition of a medium comprising two common solvents to the semisolid oils. On centrifugation, the olein and stearin are separated by the medium in the middle. Thirteen media made up from binary combinations of nine solvents, viz. water, propylene glycol, glycerine, methanol, ethanol,n-propanol, isopropanol (IPA), acetone and butanone, are found to be effective in olein-stearin separation. However, only the water/IPA and water/methanol systems have been studied in detail. The aqueous IPA provides a higher yield of olein than water/ methanol but intersolubility between oil and medium is also greater. The fractionation process can be carried out at any suitable temperature. Fractionation of the special prime bleached (SPB) palm oil at 16 C yields an olein with a cloud point of 4.8 C. Some hybrid palm oils produce a large quantity of low cloud point olein which can be bleached readily. The process can be extended to include degumming and neutralization by using an alkaline medium for centrifugation. The olein fractions obtained have been found to be free of phosphatides and the free fatty acids reduced to as low as 0.02%. Metal-scavenging agents have also been added to the medium in an attempt to remove copper and iron. The development of this process into a continuous one has been demonstrated on the AlfaLaval LAPX 202 Separator. Fractionation of crude palm oil using a density gradient provides seven fractions of different characteristics. The iodine values vary from 37.5 to 57.4 and the unsaturated fatty acids range from 32.7% to 51.2%. Triglyceride analysis by carbon numbers shows great differences in the C₄₈ and C₅₂ constituents of the fractions. aThe volume ratio of oil to medium in each case was 1:1. The separation involved the oil and wax.     

2012年一季度机床工具行业经济运行情况分析

2012年一季度我国机床工具行业增速继上年四季度之后继续大幅下滑,重点联系企业产销、利润均呈负增长。这显示出我国机床工具行业连续10年的高速增长已结束。一季度机床工具产品进口在继2009年金融危机之后再度出现负增长。高中低各档次产品     

Neisseria gonorrhoeae that infect men have lipooligosaccharides with terminal N-acetyllactosamine repeats

Infectious Neisseria gonorrhoeae make relatively large lipooligosaccharides (LOS) that structurally resemble human glycosphingolipids. MS11mkC is an LOS variant of N. gonorrhoeae strain MS11 which was isolated from men at the onset of dysuria (Schneider, H., Griffiss, J. M., Boslego, J. W., Hitchcock, P. J., Zahos, K. M., and Apicella, M. A. (1991) J. Exp. Med. 174, 1601-1605). Delayed extraction matrix-assisted laser desorption and ionization and electrospray ionization mass spectrometry of O-deacylated MS11mkC LOS produced ions consistent with known LOS which have lacto-N-neotetraose (Galbeta1-->4GlcNAcbeta1-->3Galbeta1-->4Glc; paraglobosyl; monoclonal antibodies (mAbs) 1B2(+) and 06B4(+)) and GalNAc-->lacto-N-neotetraose (gangliosyl; mAb 1-1-M+) oligosaccharides. Ion peaks for a larger LOS which also bound mAb 1B2 indicated the addition of a hexose (+162 Da) to gangliosyl LOS or the addition of a hexose and a N-acetylhexosamine (+365 Da) to paraglobosyl LOS. Analysis of HF-treated and O-deacylated LOS revealed three major components present in a phosphoethanolamine (PEA)0 and a PEA1 series. Digestion of MS11mkC LOS by beta-N-acetylhexosaminidase and beta-galactosidase, alone and sequentially, combined with mAb binding patterns, confirmed the presence of a nonreducing terminal repeating LacNAc ((Galbeta1-->4GlcNAc)2) on the largest LOS, rather than a parallel oligosaccharide structure.     

The crystal structure of human procathepsin K

Cathepsin K is a cysteine protease present in human osteoclasts that plays an important role in bone resorption. Cathepsin K is synthesized as an inactive proenzyme and activated under conditions of low pH. Autoproteolytic processing of the N-terminal 99 amino acid propeptide produces the active, mature form of cathepsin K. It is presumed that the activation of procathepsin K in vivo occurs in the bone resorption pit, which has a low-pH environment. We have determined the structure of human procathepsin K at 2.8 A resolution. The structure of the mature enzyme domain within procathepsin K is virtually identical to that of mature cathepsin K. The fold of the propeptide of procathepsin K is similar to that observed in procathepsins B and L despite differences in length and sequence. A portion of the propeptide occupies the active site cleft of cathepsin K. Hydrophobic interactions, salt bridges, and hydrogen-bonding interactions are observed in the structure of the propeptide and between the propeptide and the mature enzyme of procathepsin K. These interactions suggest an explanation for the stability of the proenzyme. The structure of procathepsin K contributes to an understanding of the molecular basis of inhibition by the propeptide portion of the molecule and activation of this important member of the cysteine protease family.