Genotyping of white spot syndrome virus in Chinese cultured shrimp during 1998–1999

Recent studies showed that white spot syndrome virus (WSSV) isolates from different geographic locations share a high genetic similarity except the variable regions in ORF23/24 and ORF14/15, and variable number of tandem repeats (VNTR) within ORF94. In this study, genotyping was performed according to these three variable regions among WSSV isolates collected during 1998/1999 from Southern China. These WSSV isolates contain a deletion of 1168, 5657, 5898, 9316 and 11093 bp, respectively in the variable region ORF23/24 compared with WSSV-TW, and a deletion of 4749 or 5622 bp in the variable region ORF14/15 relative to TH-96-II. Four types of repeat units (RUs) (6, 8, 9 and 13 RUs) in ORF94 were detected in these isolates, with the shortest 6 RUs as the most prevalent type. Our results provide important information for a better understanding of the spatio-temporal transmission mode and the WSSV genetic evolution lineage.     

Bayesian variable selection for latent class models

In this article, we develop a latent class model with class probabilities that depend on subject-specific covariates. One of our major goals is to identify important predictors of latent classes. We consider methodology that allows estimation of latent classes while allowing for variable selection uncertainty. We propose a Bayesian variable selection approach and implement a stochastic search Gibbs sampler for posterior computation to obtain model-averaged estimates of quantities of interest such as marginal inclusion probabilities of predictors. Our methods are illustrated through simulation studies and application to data on weight gain during pregnancy, where it is of interest to identify important predictors of latent weight gain classes.     

Nicotine and the behavioral mechanisms of intertemporal choice

Nicotine has been found to produce dose-dependent increases in impulsive choice (preference for smaller, sooner reinforcers relative to larger, later reinforcers) in rats. Such increases could be produced by either of two behavioral mechanisms: (1) an increase in delay discounting (i.e., exacerbating the impact of differences in reinforcer delays) which would increase the value of a sooner reinforcer relative to a later one, or (2) a decrease in magnitude sensitivity (i.e., diminishing the impact of differences in reinforcer magnitudes) which would increase the value of a smaller reinforcer relative to a larger one. To isolate which of these two behavioral mechanisms was likely responsible for nicotine's effect on impulsive choice, we manipulated reinforcer delay and magnitude using a concurrent, variable interval (VI 30 s, VI 30 s) schedule of reinforcement with 2 groups of Long-Evans rats (n = 6 per group). For one group, choices were made between a 1-s delay and a 9-s delay to 2 food pellets. For a second group, choices were made between 1 pellet and 3 pellets. Nicotine (vehicle, 0.03, 0.1, 0.3, 0.56 and 0.74 mg/kg) produced dose-dependent decreases in preference for large versus small magnitude reinforcers and had no consistent effect on preference for short versus long delays. This suggests that nicotine decreases sensitivity to reinforcer magnitude.     

The functional VNTR of IGH enhancer HS1.2 associates with human longevity and interacts with TNFA promoter diplotype in a population of Central Italy

The dysregulation of both immune and inflammatory responses occurring with aging is believed to substantially contribute to morbidity and mortality in humans. We have already reported the association of the functional Variable Number of Tandem Repeat (VNTR) at the Immunoglobulin heavy chain (IGH) enhancer HS1.2 with Immunoglobulin levels and with several autoimmune diseases. Herein we tested the association of the VNTR at the HS1.2 enhancer with human longevity, also evaluating the possible modulatory effect of TNFA promoter diplotype (rs361525/rs1800629). HS1.2 enhancer genotypes have been determined for 193 unrelated healthy individuals from Central Italy divided into two groups: Group 1 (18–84 yrs, mean age 56.8 ± 19.4) and Group 2 (85–100 yrs, mean age 93.0 ± 3.5). Homozygous subjects for *2 allele were significantly disadvantaged in reaching higher life-expectancy (OR = 0.457, p = 0.021). A significant interaction between TNFA promoter diplotype status, HS1.2 2/2 genotype and the two Groups was found (p = 0.014). Of note, TNFA − 308A allele seems to exert a protective effect in HS1.2 2/2 carriers. These results support the hypothesis of an important role of HS1.2 VNTR in the puzzle of the immune-system regulation, evidenced also by the potential interaction with TNFA. Moreover, the previous results showing the association of HS1.2 *2 allele with inflammatory phenomena are consistent with the hypothesis that this allele is a detrimental factor in reaching advanced age.     

Formation of Amyloid Fibers by Monomeric Light Chain Variable Domains

Systemic light chain amyloidosis is a lethal disease characterized by excess immunoglobulin light chains and light chain fragments composed of variable domains, which aggregate into amyloid fibers. These fibers accumulate and damage organs. Some light chains induce formation of amyloid fibers, whereas others do not, making it unclear what distinguishes amyloid formers from non-formers. One mechanism by which sequence variation may reduce propensity to form amyloid fibers is by shifting the equilibrium toward an amyloid-resistant quaternary structure. Here we identify the monomeric form of the Mcg immunoglobulin light chain variable domain as the quaternary unit required for amyloid fiber assembly. Dimers of Mcg variable domains remain stable and soluble, yet become prone to assemble into amyloid fibers upon disassociation into monomers.     

Antibody fingerprints in lyme disease deciphered with high density peptide arrays

Lyme disease is the most common tick‐borne infectious disease in Europe and North America. Previous studies discovered the immunogenic role of a surface‐exposed lipoprotein (VlsE) of Borreliella burgdorferi. We employed high density peptide arrays to investigate the antibody response to the VlsE protein in VlsE‐positive patients by mapping the protein as overlapping peptides and subsequent in‐depth epitope substitution analyses. These investigations led to the identification of antibody fingerprints represented by a number of key residues that are indispensable for the binding of the respective antibody. This approach allows us to compare the antibody specificities of different patients to the resolution of single amino acids. Our study revealed that the sera of VlsE‐positive patients recognize different epitopes on the protein. Remarkably, in those cases where the same epitope is targeted, the antibody fingerprint is almost identical. Furthermore, we could correlate two fingerprints with human autoantigens and an Epstein‐Barr virus epitope; yet, the link to autoimmune disorders seems unlikely and must be investigated in further studies. The other three fingerprints are much more specific for B. burgdorferi. Since antibody fingerprints of longer sequences have proven to be highly disease specific, our findings suggest that the fingerprints could function as diagnostic markers that can reduce false positive test results.     

青藏高原动物地理区的地位和东部界线问题

本文从历史时空的角度分析了青藏高原地区发生的鱼类区系的变化过程,和高原鱼类区系演化的相对独立性,认为这一鱼类区系的分化直接反映了高原隆升事件,并应当在动物地理区划上得到客观反映,即将青藏高原作为一个独立的区划单元。由于青藏高原的隆升和造成古北区、东洋区分化的第三纪末、第四纪初的全球性气候变冷在时间上相近、波及的范围都巨大,共同促成了欧亚大陆古北区、东洋区和青藏高原区特有类群的分化,作为对这些地史事件反映的青藏高原区、古北区和东洋区,在动物地理区划上应该具有相同的地位．另外,依据高原鱼类的分布范围和青藏高原对非高原鱼类的阻碍作用,讨论了青藏高原的界限及其划分问题。     

抗人肺腺癌单克隆抗体重,轻链可变区基因的分离克隆和序列测定

根据鼠免疫球蛋白重。轻链可变区基因ＦＲ１和ＦＲ４的序列保守性,化学合成了适于体外扩增Ｉｇ重、轻链可变区基因（Ｖ_Ｈ和Ｖ_Ｌ）的数对引物。以分泌抗人肺腺癌单抗的杂交瘤细胞株ＷＬＡ－２Ｃ４的基因组ＤＮＡ为模板,ＰＣＲ扩增Ｖ_Ｈ和Ｖ_Ｌ基因,分别克隆人ｐＵＣ１９载体。转化子经蓝、白斑筛选,酶切鉴定,双脱氧测序证实确为鼠单抗可变区基因,其中Ｖ_Ｈ基因全长为３４８ｂｐ,编码１１６ａａ,属重链ⅡＢ亚类;Ｖ_Ｌ基因全长３１８ｂｐ,编码１０６ａａ,属Ｋ轻链Ⅵ亚类。     

Novel A14841G mutation is associated with high penetrance of LHON/C4171A family

We report the clinical and genetic characterization of a Chinese LHON family carrying an ND1/C4171A mutation. This family has high penetrance of visual impairment and extremely low frequency of vision recovery, which is in marked contrast to previously reported results for Korean LHON families with the same mutation. Sequence analysis of the complete mtDNA in the partially defined East Asian haplogroup N9a1 revealed the presence of 29 other variants. A novel heteroplasmic A14841G mutation, one of the variants with a serine substituted for a highly conserved asparagine at amino acid 32 of Cytochrome b (Cytb), may play a synergistic role with the C4171A mutation, leading to significantly different clinical manifestations of LHON among these families. The study further confirmed that C4171A was a rare primary LHON mutation, and the mtDNA background could also contribute to the clinical manifestation of the LHON/C4171A mutation.