Surface charge and conformational properties of phaseolin,the major globulin in red kidney bean (Phaseolus vulgaris L): effect of pH

The aim of this investigation was to explore the pH‐induced conformational changes of phaseolin using differential scanning calorimetry (DSC), fluorescence and circular dichroism (CD) spectra. The surface charges at the varying pH and ionic strength were also determined to probe the possible relationship between the surface charges of phaseolin and its conformation. The ζ‐potential of phaseolin decreased from 27.9 mV at pH 3.0 to –44 mV at pH 9.4, and the isoelectric point (iep) occurred at pH 4.21, which were comparable with the theoretical estimations derived from amino acid composition and pK values. The iep of phaseolin was independent of ionic strength, while the magnitude of ζ‐potential decreased as the ionic strength increased. The near‐UV CD, DSC and fluorescence spectra analyses indicated highly acidic and alkaline pH conditions induced the loss of tertiary conformation of phaseolin. The far‐UV CD spectra analysis confirmed pH‐shift led to the decreases in ordered secondary structure compositions. The present results suggested the loss of secondary and/or tertiary conformation of phaseolin as a result of the varying pattern in electrostatic interactions as pH shifted from 7.0 to acidic or alkalic pH.     

Association Study between BDNF Gene Polymorphisms and Autism by Three-Dimensional Gel-Based Microarray

Single nucleotide polymorphisms (SNPs) are important markers which can be used in association studies searching for susceptible genes of complex diseases. High-throughput methods are needed for SNP genotyping in a large number of samples. In this study, we applied polyacrylamide gel-based microarray combined with dual-color hybridization for association study of four BDNF polymorphisms with autism. All the SNPs in both patients and controls could be analyzed quickly and correctly. Among four SNPs, only C270T polymorphism showed significant differences in the frequency of the allele (χ² = 7.809, p = 0.005) and genotype (χ² = 7.800, p = 0.020). In the haplotype association analysis, there was significant difference in global haplotype distribution between the groups (χ² = 28.19, p = 3.44e-005). We suggest that BDNF has a possible role in the pathogenesis of autism. The study also show that the polyacrylamide gel-based microarray combined with dual-color hybridization is a rapid, simple and high-throughput method for SNPs genotyping, and can be used for association study of susceptible gene with disorders in large samples.     

60Si_2 MnRE钢中夹杂物、微观组织和本质晶粒度的研究

采用金相和电子探针等实验方法 ,研究了 6 0Si2 Mn钢和添加稀土后的 6 0Si2 MnRE钢的夹杂物、微观组织和本质晶粒度 .发现稀土加入钢中不仅能脱硫 ,而且能显著改变硫化物夹杂的形态与分布 ,从而有利于提高钢的韧性 .     

Polymorphic and miscibility behavior in crystalline/crystalline blends of poly(pentamethylene terephthalate) with poly(heptamethylene terephthalate)

BACKGROUND: The phase behavior of blends of semicrystalline aryl polyesters with long methylene segments (? (CH₂)_n? with n = 5 or 7) in the repeat units has not been much studied. Thus, crystalline/crystalline blends comprising monomorphic poly(pentamethylene terephthalate) (PPT) and polymorphic poly(heptamethylene terephthalate) (PHepT) were prepared and the crystal growth kinetics, polymorphism behavior and miscibility in this blend system were probed using polarized‐light optical microscopy, differential scanning calorimetry and wide‐angle X‐ray diffraction. RESULTS: The PPT/PHepT blends of all compositions were first proven to be miscible in the melt state or quenched amorphous phase, whose interaction strength was determined (χ₁₂ = ? 0.35), showing favorable interactions and phase homogeneity. Although the spherulites of neat PPT and PHepT could exhibit ring bands at different crystallization temperature (T_c) ranges (100–110 and 50–65 °C, respectively), the spherulites of PPT/PHepT (50/50) blend became ringless in the range 50–110 °C. Growth analysis and polymorphic behavior in the crystalline phases of the blends provided extra evidence for the miscibility between these two crystalline polymers. Spherulitic growth rates of PPT in the PPT/PHepT blends were significantly reduced in comparison with those of neat PPT. In addition, miscible blending of a small fraction of monomorphic PPT (20 wt%) with polymorphic PHepT altered the crystal stability and led to the originally polymorphic PHepT exhibiting only the β‐crystal form when melt‐crystallized at all values of T_c. CONCLUSION: The highly intimate mixing in polymer chains of crystalline PPT and PHepT causes significant disruption in ring‐band patterns and reduction in crystallization rates of PPT as well as alteration in the polymorphic behavior of PHepT. Copyright © 2009 Society of Chemical Industry     

Selection of single-nucleotide polymorphisms and quality of genotypes used in genomic evaluation of dairy cattle in the United States and Canada

Nearly 57,000 single-nucleotide polymorphisms (SNP) genotyped with the Illumina BovineSNP50 BeadChip (Illumina Inc., San Diego, CA) were investigated to determine usefulness of the associated SNP for genomic prediction. Genotypes were obtained for 12,591 bulls and cows, and SNP were selected based on 5,503 bulls with genotypes from a larger set of SNP. The following SNP were deleted: 6,572 that were monomorphic, 3,213 with scoring problems (primarily because of poor definition of clusters and excess number of clusters), and 3,649 with a minor allele frequency of <2%. Number of SNP for each minor allele frequency class (≥2%) was fairly uniform (777 to 1,004). For 5 contiguous SNP assigned to chromosome 7, no bulls were heterozygous, which indicated that those SNP are actually on the nonpseudoautosomal portion of the X chromosome. Another 178 SNP that were not assigned to a chromosome but that had many fewer heterozygotes than expected were also assigned to the X chromosome. Existence of Hardy-Weinberg equilibrium was investigated by comparing observed with expected heterozygosity. For 11 SNP, the observed percentage of heterozygous individuals differed from the expected by >15%; therefore, those SNP were deleted. For 2,628 SNP, the genotype at another SNP was highly correlated (i.e., genotypes were identical for >99.5% of bulls), and those were deleted. After edits, 40,874 SNP remained. A parent-progeny conflict was declared when the genotypes were alternate homozygotes. Mean number of conflicts was 2.3 when pedigree was correct and 2,411 when it was incorrect. The sire was genotyped for >93% of animals. Maternal grandsire genotype was similarly checked; however, because alternate homozygotes could be valid, a conflict threshold of 16% was used to indicate a need for further investigation. Genotyping consistency was investigated for 21 bulls genotyped twice with differences primarily from SNP that were not scored in one of the genotypes. Concordance for readable SNP was extremely high (99.96-100%). Thousands of SNP that were polymorphic in Holsteins were monomorphic in Jerseys or Brown Swiss, which indicated that breed-specific SNP sets are required or that all breeds need to be considered in the SNP selection process. Genotypes from the Illumina BovineSNP50 BeadChip are of high accuracy and provide the basis for genomic evaluations in the United States and Canada.     

Al—5Ti—B变质高锌铝合金的组织和性能

研究了Al-5Ti-B变质高锌铝合金的组织和性能。金属型铝合金组织不发达的粗大α树枝晶，晶界上杂乱分布着大块状或长条状的富硅相及其他相。经钠盐精炼和0．08％Ti变质后，合金生长形状发生巨大变化，α树枝晶发达而细小，二次枝晶臂间距显著减小；硅相和其他晶间相变为球状或细短条状且均匀弥散分布在α枝晶的晶界上；晶间组织增多，变质后，抗拉强度显著提高，塑性也明显改善。     

Determination of the predominant polymorphic form of mango (Mangifera indica) almond fat by differential scanning calorimetry and X‐ray diffraction

In this paper, some important properties, from the application point of view, of mango (Mangifera indica) almond fat var. Manila (MAF) were analyzed by differential scanning calorimetry and X‐ray diffraction techniques. The thermal profile, the solid fat content (SFC) and the predominant polymorphism of MAF samples, previously characterized chemically, were studied. The results showed that this fat, from one of the main residues of mango industrialization, had a relatively simple fusion/crystallization behavior. Stabilized samples showed a simple SFC profile with one marked slope between 35 and 40 °C. Different thermal histories demonstrated the existence of at least four polymorphs. The non‐stabilized samples corresponded predominantly to the formation of the crystalline &α form. The stabilized samples, tested under several time and temperature conditions, allowed the formation of two other polymorphs, which are both unstable forms and were formed during &α to β polymorphic transition. The X‐ray diffraction information confirmed the presence of the less and more stable MAF polymorphs, allowing us to conclude that MAF is a β‐stable fat, just as is cocoa butter.     

Coding repeat instability in the FLO11 gene of Saccharomyces yeasts

In Saccharomyces yeasts, the FLO11 gene encodes an adhesin involved in filamentation, invasive growth, flocculation and adherence to solid surfaces. In wild Saccharomyces flor yeasts, a particularly expanded FLO11 allele also confers to these yeasts the ability to float under stressing liquid environments. We report here that, under optimal laboratory conditions, the repeats domain of the FLO11 gene in these wild yeasts is extremely unstable. Changes in length in the FLO11 coding repeats domain affected Flo11p‐associated functions but, interestingly, some of these functions were affected more than others. Therefore, length variations in this single gene provide a combinatorial diversity, which may contribute to a very rapid adaptation to fluctuating environments. Functional analysis of contracted alleles indicated that buoyancy was not associated to FLO11 length. In contrast, this property depended on the different types of repetitive units found in this gene. Thus, not only variations in the number of intragenic repeats but also the abundance and/or distribution of the different repetitive units may have phenotypic and evolutionary implications. Copyright © 2009 John Wiley & Sons, Ltd.     

Benzene‐di‐N‐substituted carbamates as conformationally constrained analogs of Pseudomonas lipase substrates

Benzene‐1,2‐, ‐1,3‐, and ‐1,4‐di‐N‐substituted carbamates ( 1 – 15 ) are synthesized as the constrained analogs of gauche, eclipsed, and anti conformations of diesters of ethylene glycol, respectively. Carbamates 1 – 15 are characterized as the pseudo‐substrate inhibitors of Pseudomonas species lipase. Long‐chain carbamates are more potent inhibitors than short‐chain ones. Different geometries of benzene‐di‐substituted carbamates, such as benzene‐1,2‐di‐N‐octylcarbamate ( 3 ) (ortho compound), benzene‐1,3‐di‐N‐octylcarbamate ( 8 ) (meta compound), and benzene‐1,4‐di‐N‐octylcarbamate ( 13 ) (para compound), show similar inhibitory potencies for the enzyme. In other words, kinetic data suggest that the enzyme does not discriminate ortho, meta, and para geometries of these constrained analogs.