Genetic diversity of Pogonatherum paniceum (Lam.) Hack in Southwest China revealed by ISSR

Inter-simple sequence repeats markers were used to estimate the genetic diversity of Pogonatherum paniceum (Lam.) Hack. from Sichuan Province, Yunnan Province, Chongqing City and Guangxi Zhuang Autonomous Region in China. 100 primers were carried out on 22 wild populations, 14 could produce highly reproducible inter-simple sequence repeats markersbands. Out of the 239 discernable DNA fragments, 227 were polymorphic. The percentage of polymorphic bands was 94.98% at the species level. Nei’s gene diversity and Shannon information index were 0.312 and 0.471, respectively. This indicated that the genetic diversity of P. paniceum (Lam.) Hack. was low. The values of genetic identity ranged from 0.548 to 0.820 with a mean of 0.673. Nei’s genetic distance between 22 populations ranged from 0.198 to 0.601. Unweighted pair group method with arithmetic mean cluster analysis based on Nei’s genetic distance showed that most populations were positioned into the relevant areas. Significant correlation between genetic and geographic altitude distances among populations was found by Mantel test. The high score of percentage of polymorphic bands might be caused by low frequent polymorphism distributed in different populations

A Novel Replication-Competent Vaccinia Vector MVTT Is Superior to MVA for Inducing High Levels of Neutralizing Antibody via Mucosal Vaccination

Mucosal vaccination offers great advantage for inducing protective immune response to prevent viral transmission and dissemination. Here, we report our findings of a head-to-head comparison of two viral vectors modified vaccinia Ankara (MVA) and a novel replication-competent modified vaccinia Tian Tan (MVTT) for inducing neutralizing antibodies (Nabs) via intramuscular and mucosal vaccinations in mice. MVTT is an attenuated variant of the wild-type VTT, which was historically used as a smallpox vaccine for millions of Chinese people. The spike glycoprotein (S) of SARS-CoV was used as the test antigen after the S gene was constructed in the identical genomic location of two vectors to generate vaccine candidates MVTT-S and MVA-S. Using identical doses, MVTT-S induced lower levels (∼2-3-fold) of anti- SARS-CoV neutralizing antibodies (Nabs) than MVA-S through intramuscular inoculation. MVTT-S, however, was capable of inducing consistently 20-to-100-fold higher levels of Nabs than MVA-S when inoculated via either intranasal or intraoral routes. These levels of MVTT-S-induced Nab responses were substantially (∼10-fold) higher than that induced via the intramuscular route in the same experiments. Moreover, pre-exposure to the wild-type VTT via intranasal or intraoral route impaired the Nab response via the same routes of MVTT-S vaccination probably due to the pre-existing anti-VTT Nab response. The efficacy of intranasal or intraoral vaccination, however, was still 20-to-50-fold better than intramuscular inoculation despite the subcutaneous pre-exposure to wild-type VTT. Our data have implications for people who maintain low levels of anti-VTT Nabs after historical smallpox vaccination. MVTT is therefore an attractive live viral vector for mucosal vaccination

Attenuation of Vaccinia Tian Tan Strain by Removal of Viral TC7L-TK2L and TA35R Genes

Vaccinia Tian Tan (VTT) was attenuated by deletion of the TC7L-TK2L and TA35R genes to generate MVTT3. The mutant was generated by replacing the open reading frames by a gene encoding enhanced green fluorescent protein (EGFP) flanked by loxP sites. Viruses expressing EGFP were then screened for and purified by serial plaque formation. In a second step the marker EGFP gene was removed by transfecting cells with a plasmid encoding cre recombinase and selecting for viruses that had lost the EGFP phenotype. The MVTT3 mutant was shown to be avirulent and immunogenic. These results support the conclusion that TC7L-TK2L and TA35R deletion mutants can be used as safe viral vectors or as platform for vaccines

Bioinformatics in China: A Personal Perspective

Biochemical Research MethodsMathematical & Computational BiologySCI(E)PubMed3EDITORIAL MATERIAL4e1000020

Switches between accretion structures during flares in 4U 1901+03

We report on our analysis of the 2019 outburst of the X-ray accreting pulsar 4U 1901+03 observed with Insight-HXMT and NICER. Both spectra and pulse profiles evolve significantly in the decaying phase of the outburst. Dozens of flares are observed throughout the outburst. They are more frequent and brighter at the outburst peak. We find that the flares, which have a duration from tens to hundreds of seconds, are generally brighter than the persistent emission by a factor of similar to 1.5. The pulse-profile shape during the flares can be significantly different from that of the persistent emission. In particular, a phase shift is clearly observed in many cases. We interpret these findings as direct evidence of changes of the pulsed beam pattern, due to transitions between the sub- and supercritical accretion regimes on a short time-scale. We also observe that at comparable luminosities the flares' pulse profiles are rather similar to those of the persistent emission. This indicates that the accretion on the polar cap of the neutron star is mainly determined by the luminosity, i.e. the mass accretion rate

Amphiphilic silver nanoclusters show active nano-bio interaction with compelling antibacterial activity against multidrug-resistant bacteria

Multidrug resistance represents a growing threat to human beings, and alternative antimicrobial regimens to conventional antibiotic paradigms are being extensively searched to fight against multidrug-resistant bacteria (MDRB). Although the antimicrobial potency of silver nanomaterials (AgNMs) has been previously elaborated, their efficacy against MDRB still remains to be strengthened. Here, our data revealed that small-sized silver nanoclusters (AgNCs) are superior to conventional silver nanoparticles (AgNPs) as robust antimicrobials against multidrug-resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa). The core structure and surface ligands of AgNCs are crucial for the outstanding antibacterial activity of AgNCs. On the one hand, due to the presence of amphiphilic ligands, AgNCs are relatively prone to associate with the cell membrane and partake in endocytosis with targeted bacterial cells. Molecular dynamics simulations also corroborated this finding. On the other hand, the nanocluster structure of AgNCs led to strong peroxidase-like activity associated with massive production of reactive oxygen species (ROS), which contributes to their overall bactericidal potency. These outstanding features of AgNCs result in elevated bacterial killing efficacy by impairing the cell wall/membrane, promoting oxidative stress and attenuating pivotal cellular processes, e.g., ATP synthesis. Notably, AgNCs manifested great efficacy in treating P. aeruginosa-generated pneumonia in mice and increased the survival of infected animals, as well as exhibited excellent biocompatibility. Taken together, the results of this study pinpoint the great promise of AgNCs as new alternative therapeutics against MDR P. aeruginosa. Biomaterials: A silver bullet against drug-resistant bacteriaA silver nanomaterial that can destroy drug-resistant bacteria has been developed by researchers in China. The rise of antibiotic-resistant bacteria is a major source of concern in global health. Silver has long been known to have antibacterial properties, and so scientists are returning to it as a possible agent to combat these multidrug-resistant bacteria. While silver nanoparticles have previously been shown to have good antibacterial activity, a team led by Nanfeng Zheng, Xiamen University, and Sijin Liu, Chinese Academy of Sciences, Beijing, have shown that small clusters of silver particles are even better. The researchers determined the optimal size, structure and surface properties of antibacterial nanosilver clusters. They used their nanoclusters to treat pneumonia in mice caused by the multidrug-resistant bacteria Pseudomonas aeruginosa, increasing their survival rates. Our findings unearth the great importance of the size, core structure, and surface ligands in dictating the antibacterial activity of silver nanoclusters (AgNCs). Owing to the presence of amphiphilic ligands, AgNCs are more prone to adsorb the membrane and following endocytosis towards targeted bacterial cells, associated with membrane damage, as reflected by reinforced release of malondialdehyde (MDA). AgNCs bear strong peroxidase-like activity, coupled to massive production of reactive oxygen species (ROS). Altogether, these outstanding features of AgNCs resultantly elevated the bacteria-killing efficacy through impairing cell wall/membrane, promoting oxidative stress and attenuating pivotal cellular processes, e.g., ATP synthesis. org/1999/xlink" xlink:href="41427_2020_239_Figa_HTML.png"></graphi