Novel dimer structure of a membrane-bound protease with a catalytic Ser–Lys dyad and its linkage to stomatin

The crystal structure of the K138A mutant of the 1510-N protease specific for p-stomatin was determined at 2.3 Å resolution. The structure shows a novel dimer form, and the kinked L2 loop indicates that Lys138 would probably have an important effect on the conformation of L2

Improvement of Rotavirus Genotyping Method by Using the Semi-Nested Multiplex-PCR With New Primer Set

Rotavirus A (RVA) is a major cause of gastroenteritis in infants and young children. After vaccine introduction, RVA surveillance has become more important for monitoring changes in genotype distribution, and the semi-nested multiplex-PCR is a popular method for RVA genotyping. In particular, the VP7 primer set reported by Gouvea and colleagues in 1990 is still widely used worldwide as the recommended WHO primer set in regional and national reference RVA surveillance laboratories. However, this primer set yielded some mistakes with recent epidemic strains. The newly emerged equine-like G3 strains were mistyped as G1, G8 strains were mistyped as G3, the G9 lineage 3 strains showed very weak band, and the G9 lineage 6 strains showed a G9-specific band and a non-specific band. Gouvea’s standard protocol has become relatively unreliable for identifying genotypes correctly. To overcome this limitation, we redesigned the primer set to include recent epidemic strains. Our new primer set enabled us to correctly identify the VP7 genotypes of representative epidemic strains by agarose gel electrophoresis (G1, G2, human typical G3, equine-like G3, G4, G8, G9, and G12). We believe that the multiplex-PCR method with our new primer set is a useful and valuable tool for surveillance of RVA epidemics

Effective impairment of myeloma cells and their progenitors by hyperthermia

Multiple myeloma (MM) remains incurable, and MM-initiating cells or MM progenitors are considered to contribute to disease relapse through their drug-resistant nature. In order to improve the therapeutic efficacy for MM, we recently developed novel superparamagnetic nanoparticles which selectively accumulate in MM tumors and extirpate them by heat generated with magnetic resonance. We here aimed to clarify the therapeutic effects on MM cells and their progenitors by hyperthermia. Heat treatment at 43°C time-dependently induced MM cell death. The treatment upregulated endoplasmic reticulum (ER) stress mediators, ATF4 and CHOP, while reducing the protein levels of Pim-2, IRF4, c-Myc and Mcl-1. Combination with the proteasome inhibitor bortezomib further enhanced ER stress to potentiate MM cell death. The Pim inhibitor SMI-16a also enhanced the reduction of the Pim-2-driven survival factors, IRF4 and c-Myc, in combination with the heat treatment. The heat treatment almost completely eradicated “side population” fractions in RPMI8226 and KMS-11 cells and suppressed their clonogenic capacity as determined by in vitro colony formation and tumorigenic capacity in SCID mice. These results collectively demonstrated that hyperthermia is able to impair clonogenic drug-resistant fractions of MM cells and enhance their susceptibility to chemotherapeutic drugs

Molecular Epidemiology and Clinical Features of Rotavirus Infection Among Pediatric Patients in East Java, Indonesia During 2015–2018: Dynamic Changes in Rotavirus Genotypes From Equine-Like G3 to Typical Human G1/G3

Group A rotavirus (RVA) is the most important cause of severe gastroenteritis among children worldwide, and effective RVA vaccines have been introduced in many countries. Here we performed a molecular epidemiological analysis of RVA infection among pediatric patients in East Java, Indonesia, during 2015–2018. A total of 432 stool samples were collected from hospitalized pediatric patients with acute gastroenteritis. None of the patients in this cohort had been immunized with an RVA vaccine. The overall prevalence of RVA infection was 31.7% (137/432), and RVA infection was significantly more prevalent in the 6- to 11-month age group than in the other age groups (P < 0.05). Multiplex reverse transcription-PCR (RT-PCR) revealed that the most common G-P combination was equine-like G3P[8] (70.8%), followed by equine-like G3P[6] (12.4%), human G1P[8] (8.8%), G3P[6] (1.5%), and G1P[6] (0.7%). Interestingly, the equine-like strains were exclusively detected until May 2017, but in July 2017 they were completely replaced by a typical human genotype (G1 and G3), suggesting that the dynamic changes in RVA genotypes from equine-like G3 to typical human G1/G3 in Indonesia can occur even in the country with low RVA vaccine coverage rate. The mechanism of the dynamic changes in RVA genotypes needs to be explored. Infants and children with RVA-associated gastroenteritis presented more frequently with some dehydration, vomiting, and watery diarrhea, indicating a greater severity of RVA infection compared to those with non-RVA gastroenteritis. In conclusion, a dynamic change was found in the RVA genotype from equine-like G3 to a typical human genotype. Since severe cases of RVA infection were prevalent, especially in children aged 6 to 11 months or more generally in those less than 2 years old, RVA vaccination should be included in Indonesia’s national immunization program

A pristine record of outer Solar System materials from asteroid Ryugu’s returned sample

Volatile and organic-rich C-type asteroids may have been one of the main sources of Earth’s water. Our best insight into their chemistry is currently provided by carbonaceous chondritic meteorites, but the meteorite record is biased: only the strongest types survive atmospheric entry and are then modified by interaction with the terrestrial environment. Here we present the results of a detailed bulk and microanalytical study of pristine Ryugu particles, brought to Earth by the Hayabusa2 spacecraft. Ryugu particles display a close compositional match with the chemically unfractionated, but aqueously altered, CI (Ivuna-type) chondrites, which are widely used as a proxy for the bulk Solar System composition. The sample shows an intricate spatial relationship between aliphatic-rich organics and phyllosilicates and indicates maximum temperatures of ~30 °C during aqueous alteration. We find that heavy hydrogen and nitrogen abundances are consistent with an outer Solar System origin. Ryugu particles are the most uncontaminated and unfractionated extraterrestrial materials studied so far, and provide the best available match to the bulk Solar System composition

Inactivation of SARS coronavirus by means of povidone-iodine, physical conditions, and chemical reagents

products, a number of other chemical agents, and various physical conditions were evaluated for their ability to inactivate the severe acute respiratory syndrome coronavirus (SARS-CoV). Treatment of SARS-CoV with PVP-I products for 2 min reduced the virus infectivity from 1.17 x 10⁶ TCID₅₀/ml to below the detectable level. The efficacy of 70% ethanol was equivalent to that of PVP-I products. Fixation of SARS-CoV-infected Vero E6 cells with a fixative including formalin, glutaraldehyde, methanol, and acetone for 5 min or longer eliminated all infectivity. Heating the virus at 56℃ for 5 min dramatically reduced the infectivity of the virus from 2.6 x 10⁷ to 40 TCID₅₀/ml, whereas heating the virus for 60 min or longer eliminated all infectivity. Irration with ultraviolet light at 134μQ/cm² for 15 min reduced the infectivity from 3.8 x 10⁷ to 180 TCID₅₀/ml; however, prolonged irradiation (60 min) failed to eliminate the remaining virus, leaving 18.8 TCID₅₀/ml. We beleave that these finding will be useful for the implementation of infection control measures against SARS, and for the establishment of effective guidlines for the preventation of SARS outbreaks