The processivity factor Pol32 mediates nuclear localization of DNA polymerase delta and prevents chromosomal fragile site formation in Drosophila development

The Pol32 protein is one of the universal subunits of DNA polymerase (Pol ), which is responsible for genome replication in eukaryotic cells. Although the role of Pol32 in DNA repair has been well-characterized, its exact function in genome replication remains obscure as studies in single cell systems have not established an essential role for Pol32 in the process. Here we characterize Pol32 in the context of Drosophila melanogaster development. In the rapidly dividing embryonic cells, loss of Pol32 halts genome replication as it specifically disrupts Pol localization to the nucleus. This function of Pol32 in facilitating the nuclear import of Pol would be similar to that of accessory subunits of DNA polymerases from mammalian Herpes viruses. In post-embryonic cells, loss of Pol32 reveals mitotic fragile sites in the Drosophila genome, a defect more consistent with Pol32's role as a polymerase processivity factor. Interestingly, these fragile sites do not favor repetitive sequences in heterochromatin, with the rDNA locus being a striking exception. Our study uncovers a possibly universal function for DNA polymerase ancillary factors and establishes a powerful system for the study of chromosomal fragile sites in a non-mammalian organism. Author summary Cancer etiological studies suggest that the majority of pathological mutations occurred under near normal DNA replication conditions, emphasizing the importance of understanding replication regulation under non-lethal conditions. To gain such a better understanding, we investigated the function of Pol32, a conserved ancillary subunit of the essential DNA polymerase Delta complex, through the development of the fruit fly Drosophila. We uncovered a previously unappreciated function of Pol32 in regulating the nuclear import of the polymerase complex, and this function is developmentally regulated. By utilizing mutations in pol32 and other replication factors, we have started to define basic features of Chromosome Fragile Sites (CFS) in Drosophila somatic cells. CFS is a major source of genome instability associated with replication stresses, and has been an important topic of cancer biology. We discovered that CFS formation does not favor genomic regions with repetitive sequences except the highly transcribed locus encoding ribosomal RNA. Our work lays the groundwork for future studies using Drosophila as an alternative system to uncover the most fundamental features of CFS.National Key R&D Program of China [2018YFA0107000]; National Natural Science Foundation of China [31830046, 31601162]; National Cancer Institute of America; Science and Technology Program of Guangzhou, China [201707010022]; National Institutes of Health of America [R01GM123640]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Epidemiology and immunoprotection of nephropathogenic avian infectious bronchitis virus in southern China

<p>Abstract</p> <p>Background</p> <p>In last three years, 96 suspected poultry farms from different provinces in China were diagnosed for avian infectious bronchitis (IB) survey. Finally, 221 IBV strains were confirmed by dwarf embryo test and RT-PCR assay. By virus recovery trials, 187 of the isolates caused the birds died or distressed from nephritis, which was accordant with the clinical record.</p> <p>Results</p> <p>Based on epidemiology analysis of recent field isolates of nephropathogenic IB in vaccinated farms in China, YL6 strain were used for vaccination and evaluated by antibody titer and challenge tests. The immunoprotection test indicated that the practical application of vaccine based on the recent field strains could finely facilitate controlling the nephropathogenic IB.</p> <p>Conclusions</p> <p>Our study was aim at setting a guide for safeguard against nephropathogenic IBV-caused disease in China.</p

RETRACTED: An empirical investigation of the impact of renewable and non-renewable energy consumption and economic growth on climate change, evidence from emerging Asian countries

One of the greatest challenges facing humanity in the current millennium is the need to mitigate climate change, and one of the most viable options to overcome this challenge is to invest in renewable energy. The study dynamically examines the impact of renewable and non-renewable energy consumption and economic growth on climate change, using Augmented Mean Group (AMG) technique in emerging Asian countries during the period 1975–2020. The estimated results show that the consumption of renewable energy sources significantly mitigates climate change, while the consumption of non-renewable energy sources significantly contributes to climate change. Furthermore, economic growth, investment in transport infrastructure, and urbanization significantly accelerate climate change in specific emerging Asian countries. The results further demonstrate the validity of the inverted U-shaped EKC hypothesis in emerging Asian economies. Country-specific analysis results using AMG estimates shows that renewable energy consumption reduces climate change for all specific emerging Asian countries. However, the consumption of non-renewable energy sources and investments in transport infrastructure have significant incremental impacts on climate change in all countries. Urbanization contributes significantly to climate change, with the exception of Japan, which does not have any significant impact on climate change. The significant progressive effect of GDP and the significant adverse impact of GDP2 on climate change confirm the validity of the inverted U-shaped EKC hypothesis in India, China, Japan, and South Korea. Moreover, the Dumitrescu and Hurlin causality test confirmed a pairwise causal relationship between non-renewable energy consumption and GDP, supporting the feedback hypothesis. According to the empirical analysis of this study, the best strategy for climate change mitigation in specific emerging countries in Asia is to transition from non-renewable energy to renewable energy

Phylogenetic distribution and predominant genotype of the avian infectious bronchitis virus in China during 2008-2009

<p>Abstract</p> <p>Background</p> <p>The nephropathogenic avian infectious bronchitis (IB) caused unprecedented economic losses to the commercial chicken industry of China in 2008-2009. To investigate the prevalence of nephropathogenic IB in China, eighty IBV isolates from different provinces during 2008-2009 were identified by dwarf embryo test and RT-PCR.</p> <p>Results</p> <p>The strains were mostly isolated in winter and spring with a wide age range of IB outbreaks, from 4 to 69 days. By the virus recovery trials, 70/80 of the strains resulted in the deaths or distresses of birds from nephritis. To learn more about the molecular evolutionary characteristics of the circulating field strains, the coding region of major spike 1 (S1) protein gene of these strains was RT-PCR amplified and sequenced. Compared to the published representative strains, nucleotides and amino acids sequence analysis indicated that the S1 genes of these strains and the reference strains displayed homologies ranging from 75.1% to 99.8% and from 73.1% to 99.8% respectively. S1 protein of the major pandemic strains contained 540 or 542 amino acids with the cleavage site of HRRRR or RRFRR. Phylogenetic analysis revealed that recent field isolates of IBV in China were mostly belonged to A2-branch (QXIBV-branch) and HN08-branch, only one isolate was belonged to Gray-branch and M41-branch respectively. Most of the 80 strains showed evolutionarily distant from vaccine strains.</p> <p>Conclusions</p> <p>The results of this study suggested that nephropathogenic IBVs were mainly A2-like strains in China during 2008-2009.</p

Isolation and complete genomic characterization of H1N1 subtype swine influenza viruses in southern China through the 2009 pandemic

<p>Abstract</p> <p>Background</p> <p>The swine influenza (SI) is an infectious disease of swine and human. The novel swine-origin influenza A (H1N1) that emerged from April 2009 in Mexico spread rapidly and caused a human pandemic globally. To determine whether the tremendous virus had existed in or transmitted to pigs in southern China, eight H1N1 influenza strains were identified from pigs of Guangdong province during 2008-2009.</p> <p>Results</p> <p>Based on the homology and phylogenetic analyses of the nucleotide sequences of each gene segments, the isolates were confirmed to belong to the classical SI group, with HA, NP and NS most similar to 2009 human-like H1N1 influenza virus lineages. All of the eight strains were low pathogenic influenza viruses, had the same host range, and not sensitive to class of antiviral drugs.</p> <p>Conclusions</p> <p>This study provides the evidence that there is no 2009 H1N1-like virus emerged in southern China, but the importance of swine influenza virus surveillance in China should be given a high priority.</p

Decadal soil carbon accumulation across Tibetan permafrost regions

Acknowledgements We thank the members of Peking University Sampling Teams (2001–2004) and IBCAS Sampling Teams (2013–2014) for assistance in field data collection. We also thank the Forestry Bureau of Qinghai Province and the Forestry Bureau of Tibet Autonomous Region for their permission and assistance during the sampling process. This study was financially supported by the National Natural Science Foundation of China (31670482 and 31322011), National Basic Research Program of China on Global Change (2014CB954001 and 2015CB954201), Chinese Academy of Sciences-Peking University Pioneer Cooperation Team, and the Thousand Young Talents Program.Peer reviewedPostprintPostprin

Activation Mode Effects on the Shear Bond Strength of Dual-cured Resin Cements

Objectives: This study evaluated the immediate (10-minute) and delayed (24-hour) bond strength of dual-cured resin cements that are light-activated either immediately or delayed (after five minutes) or chemically-activated only. Materials and Methods: Three dual-cured resin cements were evaluated: RelyX ARC, Panavia F and Enforce. Cylinders of resin cement were built up over resin composite blocks following the manufacturers’ instructions for each luting agent. The cements were mixed, inserted into the molds and light-activated either immediately or after five minutes (delayed light activation). When no light activation was performed, the materials were protected from light exposure until testing. Half of the samples were tested at 10 minutes; the remaining samples were stored at 100% relative humidity for 4 hours when they were then test ed (n=10). Data were submitted to three-way ANOVA and post-hoc Tukey’s tests (α=0.05). The failure mode was evaluated under SEM. Results: RelyX ARC presented the highest values of shear bond strength, followed by Enforce. Panavia F showed the lowest values. Both immediate and delayed light activation caused the cements to present the highest means of shear bond strength. There was an improvement in bond strength after 24 hours of storage. Conclusions: RelyX ARC produced the highest bond strength, which was improved by light activation and storage for 24 hours

Satellite testing of a gravitationally induced quantum decoherence model

Quantum mechanics and the general theory of relativity are two pillars of modern physics. However, a coherent unified framework of the two theories still remains an open problem. Attempts to quantize general relativity have led to many rival models of quantum gravity, which, however, generally lack experimental foundations. We report a quantum optical experimental test of event formalism of quantum fields, a theory which attempts to present a coherent description of quantum fields in exotic spacetimes containing closed timelike curves and ordinary spacetime. We experimentally test a prediction of the theory with the quantum satellite Micius that a pair of time-energy entangled particles probabilistically decorrelate passing through different regions of the gravitational potential of Earth. Our measurement results are consistent with the standard quantum theory and hence do not support the prediction of event formalism