Long-Lasting Immune Protection and Other Epidemiological Findings after Chikungunya Emergence in a Cambodian Rural Community,April 2012

The East/Central/South African genotype of Chikungunya virus with the E1-A226V mutation emerged in 2011 in Cambodia and spread in 2012. An outbreak of 190 cases was documented in Trapeang Roka, a rural village. We surveyed 425 village residents within 3–4 weeks after the outbreak, and determined the sensitivity and specificity of case definitions and factors associated with infection by CHIKV. Self-reported clinical presentation consisted mostly of fever, rash and arthralgia. The presence of all three clinical signs or symptoms was identified as the most sensitive (67%) and specific (84%) self-reported diagnostic clinical indicator compared to biological confirmation by MAC-ELISA or RT-PCR used as a reference. Having an indoor occupation was associated with lower odds of infection compared with people who remained at home (adjOR 0.32, 95%CI 0.12–0.82). In contrast with findings from outbreaks in other settings, persons aged above 40 years were less at risk of CHIKV infection, likely reflecting immune protection acquired when Chikungunya circulated in Cambodia before the Khmer Rouge regime in 1975. In view of the very particular history of Cambodia, our epidemiological data from Trapeang Roka are the first to support the persistence of CHIKV antibodies over a period of 40 years.     

A novel thermostable alpha-galactosidase from the thermophilic fungus Thermomyces lanuginosus CBS 395.62/b: purification and characterization

High levels of an extracellular alpha-galactosidase are produced by the thermophilic fungus Thermomyces lanuginosus CBS 395.62/b when grown in submerse culture and induced by sucrose. The enzyme was purified 114-fold from the culture supernatant by (NH(4))(2)SO(4) fractionation, and by chromatographical steps including Sepharose CL-6B gel filtration, DEAE-Sepharose FF anion-exchange, Q-Sepharose FF anion-exchange and Superose 12 gel filtration. The purified enzyme exhibits apparent homogeneity as judged by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and iso-electric focusing (IEF). The native molecular weight of the monomeric alpha-galactosidase is 93 kDa with an isoelectric point of 3.9. The enzyme displays a pH and temperature optimum of 5-5.5 and 65 degrees C, respectively. The purified enzyme retains more than 90% of its activity at 45 degrees C in a pH range from 5.5 to 9.0. The enzyme proves to be a glycoprotein and its carbohydrate content is 5.3%. Kinetic parameters were determined for the substrates p-nitrophenyl-alpha-galactopyranoside, raffinose and stachyose and very similar K(m) values of 1.13 mM, 1.61 mM and 1.17 mM were found. Mn(++) ions activates enzyme activity, whereas inhibitory effects can be observed with Ca(++), Zn(++) and Hg(++). Five min incubation at 65 degrees with 10 mM Ag(+) results in complete inactivation of the purified alpha-galactosidase. Amino acid sequence alignment of N-terminal sequence data allows the alpha-galactosidase from Thermomyces lanuginosus to be classified in glycosyl hydrolase family 36.     

Developmentally Arrested Precursors of Pontine Neurons Establish an Embryonic Blueprint of the Drosophila Central Complex

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Improved expression of porcine epidemic diarrhea antigen by fusion with cholera toxin B subunit and chloroplast transformation in Nicotiana tabacum

The porcine epidemic diarrhea virus (PEDV) belongs to the coronavirus family, which causes acute diarrhea in pigs with higher mortality in piglets less than 2 weeks old. The PEDV is one of the major concerns of the pig industry around the world, including Asian countries and Noth America since first identified in Europe. Currently, there is no PEDV licensed vaccine to effectively prevent this disease. This study was performed for the development of a mucosal PEDV vaccine and B subunit of cholera toxin (CTB) as a carrier was employed to surpass the tolerogenic nature of GALT and induce potent immune responses against the target antigen fused to CTB. An epitope (S1D) alone or conjugated with CTB was constructed into the tobacco chloroplasts expression vector which is controlled under the chloroplast rRNA operon promoter with T7g10 5′ UTR and the psbA 3′UTR as a terminator. The homoplastomic lines were obtained by third round screening via organogenesis from the leaf tissues which were verified by PCR with antigen and chloroplast specific primers and then confirmed by Southern blot analysis. While the expression level of the S1D alone as detected by Western blotting was approximately 0.07% of total soluble protein, the CTB-S1D fusion protein was expressed up to 1.4%. The fusion protein showed binding to the intestinal membrane GM1-ganglioside receptor, demonstrating its functionality. The result shows that the highest expression of S1D could be achieved by fusion with a stable CTB protein and chloroplast transformation. Furthermore, the CTB-S1D expressed in chloroplasts of Nicotiana tabacum cv. Maryland could be assembled to pentameric form which increases the possibility to develop a mucosal vaccine against PEDV.

     

Creating Multiband and Broadband Metamaterial Absorber by Multiporous Square Layer Structure

Plasmonics - Since the metamaterial perfect absorber (MPA) is composed of electromagnetic resonance structures, the main operational mechanism of the MPA is electromagnetic resonance. In this work,...     

Quantifying and Understanding Voltage Losses Due to Nonradiative Recombination in Bulk Heterojunction Organic Solar Cells with Low Energetic Offsets

Open‐circuit voltage (V_OC) losses in organic photovoltaics (OPVs) inhibit devices from reaching V_OC values comparable to the bandgap of the donor–acceptor blend. Specifically, nonradiative recombination losses (?V_nr) are much greater in OPVs than in silicon or perovskite solar cells, yet the origins of this are not fully understood. To understand what makes a system have high or low loss, an investigation of the nonradiative recombination losses in a total of nine blend systems is carried out. An apparent relationship is observed between the relative domain purity of six blends and the degree of nonradiative recombination loss, where films exhibiting relatively less pure domains show lower ?V_nr than films with higher domain purity. Additionally, it is shown that when paired with a fullerene acceptor, polymer donors which have bulky backbone units to inhibit close π–π stacking exhibit lower nonradiative recombination losses than in blends where the polymer can pack more closely. This work reports a strategy that ensures ?V_nr can be measured accurately and reports key observations on the relationship between ?V_nr and properties of the donor/acceptor interface.