Microsatellites in pursuit of microbial genome evolution

Microsatellites or short sequence repeats are widespread genetic markers which are hypermutable 1-6bp long short nucleotide motifs. Significantly, their applications in genetics are extensive due to their ceaseless mutational degree, widespread length variations and hypermutability skills. These features make them useful in determining the driving forces of evolution by using powerful molecular techniques. Consequently, revealing important questions, for example, what is the significance of these abundant sequences in DNA, what are their roles in genomic evolution? The answers of these important questions are hidden in the ways these short motifs contributed in altering the microbial genomes since the origin of life. Even though their size ranges from 1 –to- 6 bases, these repeats are becoming one of the most popular genetic probes in determining their associations and phylogenetic relationships in closely related genomes. Currently, they have been widely used in molecular genetics, biotechnology and evolutionary biology. However, due to limited knowledge; there is a significant gap in research and lack of information concerning hypermutational mechanisms. These mechanisms play a key role in microsatellite loci point mutations and phase variations. This review will extend the understandings of impacts and contributions of microsatellite in genomic evolution and their universal applications in microbiology

Engineering production of functional scFv antibody in E. coli by co-expressing the molecule chaperone Skp

Single-chain variable fragment (scFv) is a class of engineered antibodies generated by the fusion of the heavy (VH) and light chains (VL) of immunoglobulins through a short polypeptide linker. ScFv play a critical role in therapy and diagnosis of human diseases, and may in fact also be developed into a potential diagnostic and/or therapeutic agent. However, the fact that current scFv antibodies have poor stability, low solubility and affinity, seriously limits their diagnostic and clinical implication. Here we have developed four different expression vectors, and evaluated their abilities to express a soluble scFv protein. The solubility and binding activity of the purified proteins were determined using both SDS-PAGE and ELISA. Amongst the four purified proteins, the Skp co-expressed scFv showed the highest solubility, and the binding activity to antigen TLH was 3-4 fold higher than the other three purified scFv. In fact, this scFv is specific for TLH and does not cross-react with other TLH-associated proteins and could be used to detect TLH directly in real samples. These results suggest that the pACYC-Duet-skp co-expression vector might be a useful tool for the production of soluble and functional scFv antibody

The pathogenesis, detection and prevention of Vibrio parahaemolyticus

Vibrio parahaemolyticus, a Gram-negative motile bacterium that inhabits marine and estuarine environments throughout the world, is a major food-borne pathogen that causes life-threatening diseases in humans after the consumption of raw or undercooked seafood. The global occurrence of V. parahaemaolyticus accentuates the importance of investigating its virulence factors and their effects on the human host. This review describes the virulence factors of V. parahaemolyticus reported to date, including hemolysin, urease, two type III secretion systems (T3SS) and two type VI secretion systems (T6SS), which both cause both cytotoxicity in cultured cells and enterotoxicity in animal models. We describe various types of detection methods, based on virulence factors, that are used for quantitative detection of V. parahaemolyticus in seafood. We also discuss some useful preventive measures and therapeutic strategies for the diseases mediated by V. parahaemolyticus, which can reduce, to some extent, the damage to humans and aquatic animals attributable to V. parahaemolyticus. This review extends our understanding of the pathogenic mechanisms of V. parahaemolyticus mediated by virulence factors and the diseases it causes in its human host. It should provide new insights for the diagnosis, treatment, and prevention of V. parahaemolyticus infection

Forms of Aggression, Peer Relationships, and Relational Victimization among Chinese Adolescent girls and boys: Roles of Prosocial Behavior

Through a sample of 686 Chinese adolescents (mean age = 13.73 years; 50% girls), we examined the compensatory and moderating effects of prosocial behavior on the direct and indirect associations between forms of aggression and relational victimization mediated by peer relationships among adolescent girls and boys. The results indicated that only adolescent girls’ relationally aggressive behaviors could be directly linked with their experiences of relational victimization, and both relationally and overtly aggressive adolescent boys and girls might be more often rejected by their peers, which, in turn, could make them targets of relational aggression. Next, we found that prosocial behavior indirectly counteracts the effects of aggression on relational victimization through reducing adolescents’ peer rejection and promoting adolescents’ peer attachment. In addition, relationally aggressive girls with high levels of prosocial behavior might be less rejected by peers; however, they might also have lower levels of peer attachment and be more likely to experience relational victimization. Last, adolescent boys scored higher on risks, but lower on the protective factors of relational victimization than girls, which, to some degree, might explain the gender difference in relational victimization. Finally, we discussed the theoretical and practical implications of these findings

Genome analysis of orf virus isolates from goats in the Fujian Province of southern China

Orf virus (ORFV), a species of the genus Parapoxvirus of the family Poxviridae, causes nonsystemic, highly contagious and eruptive disease in sheep, goat, and other wild and domestic ruminants. Our previous work shows orf to be ubiquitous in the Fujian Province of China, a region where there is considerable heterogeneity among ORFVs. In this study, we sequenced full genomes of four Fujian goat ORFV strains (OV-GO, OV-YX, OV-NP and OV-SJ1). The four strains were 132 to 139 kb in length, with each containing 124 to 132 genes and about 64% G+C content. The most notable differences between the four strains were found near the genome termini. OV-NP lacked seven and OV-SJ1 lacked three genes near the right terminus when compared against other ORFVs. We also investigated the skin-virulence of the four Fujian ORFVs in goats. The ORFVs with gene deletions showed low virulence while the ORFVs without gene deletions showed high virulence in goats suggesting gene deletion possibly leads to attenuation of ORFVs. Gene 134 was disrupted in OV-NP genome due to the lack of initial code. The phylogenetic tree based on complete Parapoxviruse genomes showed that sheep originated and goat originated ORFVs formed distinctly separate branches with 100% bootstrap. Based on the single gene phylogenetic tree of 132 genes of ORFVs, 32 genes can be easily distinguished as having originated from sheep or goats. Multiple alignment of amino acid sequences of gene 008 from the genome of 5 goat ORFVs and 4 sheep ORFVs revealed 33 unique amino acids differentiating it as having sheep or goats as host. The availability of genomic sequences of four Fujian goat ORFVs aids in our understanding of the diversity of orf virus isolates in this region and can assist in distinguishing between orf strains that originate in sheep and goats