Molecular characterization of partial-open reading frames 1a and 2 of the human astroviruses in South Korea

Human astroviruses (HAstVs) are among the major causes of gastroenteritis in South Korea. In this study, the partial regions of the open reading frame (ORF) 1a and ORF2 genes of HAstVs from gastroenteritis patients in nine hospitals were sequenced, and the molecular characterization of the viruses was revealed. 89 partial nucleotide sequences of ORF1a and 88 partial nucleotide sequences of ORF2 were amplified from 120 stool specimens. Phylogenetic analysis showed that most of the nucleotide sequences of ORF1a and ORF2 were grouped with HAstV type 1 but had evolutionary genetic distance compared with the reference sequences, such as the HAstV-1 prototype, Dresden strain, and Oxford strain. According to the phylogenetic analysis, some nucleotide sequences including SE0506041, SE0506043, and SE0506058, showed the discrepancy of the genotypes, but there was no proof of recombination among the HAstV types. In conclusion, this study showed that the dominant HAstV isolated from the Seoul metropolitan area in 2004-2005 was HAstV type 1, and that Korean HAstV-1 had the genetic distance in evolution compared with the reference sequences of HAstVs. Lots of nucleotide sequences of the ORF1a and ORF2 genes of HAstV will be useful for studying for the control and prevention of HAstV gastroenteritis in South Korea

Serological Studies Confirm the Novel Astrovirus HMOAstV-C as a Highly Prevalent Human Infectious Agent

Molecular identification of a microbe is the first step in determining its prevalence of infection and pathogenic potential. Detection of specific adaptive immune responses can provide insights into whether a microbe is a human infectious agent and its epidemiology. Here we characterized human anti-IgG antibody responses by luciferase immunoprecipitation systems (LIPS) against two protein fragments derived from the capsid protein of the novel HMOAstV-C astrovirus. While antibodies to the N-terminal fragment were not informative, the C-terminal capsid fragment of HMOAstV-C showed a high frequency of immunoreactivity with serum from healthy blood donors. In contrast, a similar C-terminal capsid fragment from the related HMOAstV-A astrovirus failed to show immunoreactivity. Detailed analysis of adult serum from the United Sates using a standardized threshold demonstrated HMOAstV-C seropositivity in approximately 65% of the samples. Evaluation of serum samples from different pediatric age groups revealed that the prevalence of antibodies in 6–12 month, 1–2 year, 2–5 year and 5–10 year olds was 20%, 23%, 32% and 36%, respectively, indicating rising seroprevalence with age. Additionally, 50% (11/22) of the 0–6 month old children showed anti-HMOAstV-C antibody responses, likely reflecting maternal antibodies. Together these results document human humoral responses to HMOAstV-C and validate LIPS as a facile and effective approach for identifying humoral responses to novel infectious agents

MEMS Technologies for Energy Harvesting

The objective of this chapter is to introduce the technology of Microelectromechanical Systems, MEMS, and their application to emerging energy harvesting devices. The chapter begins with a general introduction to the most common MEMS fabrication processes. This is followed with a survey of design mechanisms implemented in MEMS energy harvesters to provide nonlinear mechanical actuations. Mechanisms to produce bistable potential will be studied, such as introducing fixed magnets, buckling of beams or using slightly slanted clamped-clamped beams. Other nonlinear mechanisms are studied such as impact energy transfer, or the design of nonlinear springs. Finally, due to their importance in the field of MEMS and their application to energy harvesters, an introduction to actuation using piezoelectric materials is given. Examples of energy harvesters found in the literature using this actuation principle are also presented

Molecular characterization of the VP1, VP2, VP4, VP6, NSP1 and NSP2 genes of bovine group B rotaviruses: identification of a novel VP4 genotype

Studies on bovine group B rotaviruses (GBRs) are limited. To date, only the VP6 gene of a single bovine GBR strain and the VP7 and NSP5 genes of a few bovine GBR strains have been sequenced and analyzed. In the present study, using a single-primer amplification method, we have determined the full-length nucleotide sequences of the VP1, VP2, VP4, VP6, NSP1 and NSP2 genes of three bovine GBR strains from eastern India. In all six of these genes, the bovine GBR strains shared high genetic relatedness among themselves but exhibited high genetic diversity with cognate genes of human, murine and ovine GBRs. Interestingly, as with group A rotaviruses, the bovine GBR VP1, VP2, VP6 and NSP2 genes appeared to be more conserved than the VP4 and NSP1 genes among strains of different species. The present study provides important insights into the genetic makeup and diversity of bovine GBRs, and also identifies a novel GBR VP4 genotype