Molecular basis for the reversible ADP-ribosylation of guanosine bases.

Modification of nucleic acids by ADP-ribosylation is catalyzed by various ADP-ribosyltransferases, including the DarT enzyme. The latter is part of the bacterial toxin-antitoxin (TA) system DarTG, which was shown to provide control of DNA replication and bacterial growth as well as protection against bacteriophages. Two subfamilies have been identified, DarTG1 and DarTG2, which are distinguished by their associated antitoxins. While DarTG2 catalyzes reversible ADP-ribosylation of thymidine bases employing a macrodomain as antitoxin, the DNA ADP-ribosylation activity of DarTG1 and the biochemical function of its antitoxin, a NADAR domain, are as yet unknown. Using structural and biochemical approaches, we show that DarT1-NADAR is a TA system for reversible ADP-ribosylation of guanosine bases. DarT1 evolved the ability to link ADP-ribose to the guanine amino group, which is specifically hydrolyzed by NADAR. We show that guanine de-ADP-ribosylation is also conserved among eukaryotic and non-DarT-associated NADAR members, indicating a wide distribution of reversible guanine modifications beyond DarTG systems.

Prevalence of noroviruses in children hospitalized for acute gastroenteritis in Hohhot, China, 2012-2017.

BACKGROUND: Noroviruses (NVs) are an important cause of acute gastroenteritis (AGE) worldwide. There are limited data on the prevalence and molecular characterization of NVs in children in Hohhot, China. METHODS: Between January 2012 and December 2017, 1863 stool samples were collected at Maternal and Child Health Hospital in Hohhot. All samples were screened for NVs by real-time reverse transcription polymerase chain reaction (real-time RT-PCR). RESULTS: NVs were detected in 24.15% of these inpatient cases, ranging from 12.78 to 32.92% in different years. NV was detected throughout the year, with a peak in winter. Based on sequence analysis of the partial VP1 gene, the 306 identified NV strains were divided into six genotypes: GII.3 (71.24%), GII.4 (23.53%), and GII.2, GII.5, GII.6, and GII.13 (total 5.23%). Based on further sequence analysis of the RNA-dependent RNA polymerase (RdRp), GII.P12/GII.3, GII.Pe/GII.4, and GII.P4/GII.4 were identified as predominant genotypes, accounting for 92.6% of genotyped strains. The median age of the children with NV infection was 8.0 (range 0-59) months. However, children infected with GII.3 were younger (median 7.0 months) than GII.4-positive patients (median 10.0 months). CONCLUSION: NV contributed greatly to AGE among hospitalized children in Hohhot in China. Continuous surveillance is important for understanding the local prevalence and characterization of NV.

Numerical study on the characteristics of roadway failure and instability in coal seam with rock parting.

In order to explore the mechanism of rockburst in coal seam with rock parting, a combination of on-site and numerical experiment is used to study the failure and instability process, crack propagation mechanism, and influencing factors. The following four points were addressed: (1) the instability is a process that roadway in coal seam with rock parting go through from stable locking in the initial stress unloading stage to slipping unlocking, and then to spatter ejection in slipping dynamic load disturbance stage. (2) The fracture development caused by unloading excavation of coal seam with rock parting will change from shear crack to tensile crack. In this process, coal-rock contact surface slip and coal-rock fracture are coupled with each other. (3) The greater the mining depth is, the greater the lateral pressure coefficient is, and the higher the rockburst risk is. On the contrary, the lower the risk of rockburst. (4) When choosing the support form of roadway in coal seam with rock parting, the two supporting forms of bolting (cable) and supplementary masonry support should be preferred. The results enrich the theory of the dynamics of surrounding rock fracture in coal mine, further clarify the potential dangers to mining-area roadways and working faces, and provide technical information to ensure the safe and efficient mining of bifurcated coal seam.

Genomic sequence analysis of a new reassortant infectious bursal disease virus from commercial broiler flocks in Central China.

We report the complete nucleotide sequence of a reassortant infectious bursal disease (IBD) virus (IBDV) HN isolate from commercial broiler flocks in central China. The genome consisted of 3,232 and 2,652 nucleotides in the coding regions of segments A and B, respectively. Alignment of both nucleotide and deduced amino acid sequences and phylogenetic analysis revealed that the genome segments A and B of HN were derived from the attenuated strain B87 and the VV strain OKYM. This is a new reassortant IBDV strain that has emerged in nature, involving segment A of a cell-culture-adapted attenuated vaccine strain B87.

Changed epidemiology of anthrax and molecular characteristics of Bacillus anthracis in Inner Mongolia Autonomous Region, China.

Anthrax is a natural foci disease in Inner Mongolia, which poses a severe threat to public health. In this study, the incidence number, rate and constituent ratio were used to describe the epidemiological characteristics of anthrax in the region from 1956-2018. The molecular correlation and genetic characteristics of the strains were investigated using canonical single nucleotide polymorphisms (CanSNP), multiple-locus variable-number tandem repeat analysis (MLVA-15) and whole genome sequencing (WGS). The epidemiological characteristics of anthrax in Inner Mongolia have altered significantly. The incidence of anthrax has decreased annually without vaccination, and the regional distribution of anthrax gradually transferred from central and western regions to the eastern. Moreover, the occupation distribution evolved from multiple early occupations to predominated by farmers and herdsmen. This change is closely related to policy factors and to changes in the means of production and the living habits of the local population. This indicates that reformulating the control and prevention strategies is essential. Both A. Br. Ames and A. Br. 001/002 subgroups were the predominant CanSNP genotypes of Bacillus anthracis in Inner Mongolia. A total of 36 strains constituted six shared MLVA-15 genotypes, suggesting an epidemiological link between the strains of each shared genotype. The six shared genotypes ([GT1, 9, 11 and 15] and [GT8 and 12]) consisting of 2-7 strains confirmed the occurrence of multiple point outbreaks and cross-regional transmission caused by multiple common sources of infection. Phylogenetic analysis based on the WGS core genome showed that strains from this study formed an independent clade (C.V.), and they were positioned close to each other, suggesting a common origin. Further comparison analysis should be performed to ascertain the geographic origin of these strains.

[Analysis of mite-allergic characteristics in patients with allergic rhinitis].

OBJECTIVE: To investigate the characteristics of allergic rhinitis sensitized with mite, providing the evidence for the treatment plan of allergic rhinitis in Tianjin area. METHOD: The medical records of skin prick test results on 2390 allergic rhinitis patients from March 2009 to February 2012 were retrospectively studied. The data of mite sensitivity in gender, age, season, and regional differences were analyzed. RESULT: There was no significant difference of the positive rate of Dermatophagoides pteronyssinus and Dermatophagoides farinae between male and female (P > 0. 05); The positive rate of dust mite decreased gradually with the growth of the age in the three groups of < 18,18-39,40-60 years old, but the positive rate of the patients over the age of 60 years old increased then. There were significant differences of positive rate to dust mite in different season (P < 0.05). The positive rate of Dermatophagoides pteronyssinus was the highest in the autumn (55.4%), and the lowest in winter (39.7%). The positive rate of Dermatophagoides farinae was the highest in winter (73.8%), and the lowest in spring (47.2%). There was no significant difference of the positive rate to dust mite between urban and suburb (P > 0.05). CONCLUSION: There were some relationship of the positive rate of dust mite with age and season, but not gender and region among allergic rhinitis in tianjin.

[Analysis of allergen variation for 3292 patients with allergic rhinitis].

OBJECTIVE: To investigate the variation of common allergens in patients with allergic rhinitis in recent 4 years in Tianjin First Center Hospital. METHODS: The medical records of skin prick test on 3292 patients with allergic rhinitis between 2009 and 2012 were restrospectively analyzed. The changing trend of various allergens in 4 years and distribution differences were compared. The differences of the top 5 allergens in under age group, adult group and different gender group were further analyzed by SPSS 19.0 software. RESULTS: The positive rate of dermatophagoides farinae was increasing year by year, from 45.1% in 2009 to 66.3% in 2012, and the positive rate of dermatophagoides pteronyssinus increased from 42.0% in 2009 to 58.6% in 2012, the difference was statistically significant (χ(2) value was 68.70, 41.55, all P < 0.01). The positive rate of dermatophagoides farinae and dermatophagoides pteronyssinus in adult group and male group showed significant upward trend year by year (χ(2) value was 75.85, 69.93, 274.25, 42.62, all P < 0.01), but not in adult group and female group. The positive rate of quinoa, mugwort and humulus scandens decreased year by year between 2009 and 2011(χ(2) value was 22.08, 11.64, 203.19, all P < 0.01), but increased again in 2012(χ(2) value was 21.55, 29.38, 12.40, all P < 0.01). CONCLUSIONS: There is a tendency of change of allergens in patients with AR. This phenominon may be helpful for doctors to choose the type of skin prick liquid.

[Survey on the distribution of common allergens responsible for cases with allergic rhinitis in Tianjin district].

OBJECTIVE: To investigate the distribution of common allergens responsible for cases with allergic rhinitis in Tianjin district. METHOD: A total of 676 cases who are diagnosed with allergic rhinitis in Tianjin district, underwent a skin prick tests with 23 kinds of inhaling allergens and 20 kinds of ingestive ones. The samples were stratified on four age group. Then, an analysis was made to determine the distributive characteristics of allergens responsible for difference groups. RESULT: Among the surveyed local 676 cases with allergic rhinitis, higher positive rates was all inhaling group of allergens. CONCLUSION: It is concluded that the mostly responsible common allergens for attacks of allergic rhinitis among local cases in Tianjin district are mites, flowers pollen in inhaling group of allergens.

[Objective evaluation of nasal ventilation function in healthy adults in Tianjin area].

OBJECTIVE: To establish reference values of acoustic rhinometry, rhinomanometry and rhinospirometer in healthy adults in Tianjin area, analyze the effects of age,sex and side on the value, investigate the correlation of the measure values, offer the diagnosis date for test nasal ventilation function in Tianjin area. METHOD: Four hundred and sixty-six healthy adults in Tianjin area were tested. A1 acoustic rhinometry was used to measure the minimum cross-sectional area (MCA), distance of the minimal cross-sectional area to the nostril (DCAN) and the nasal volume from 0-5 cm, 2-5 cm (V5, V2-5); At 150 Pa, 75 Pa and broms, NR6 Rhinomanometry was used to measure unilateral nasal inspiratory resistance (IR)and expiratory resistance (ER), bilateral nasal inspiratory and expiratory resistance (TIR and TER), and differences of the bilateral nasal resistance can be calculated; NV1 Rhinospirometer was used to measure unilateral inspiratory capacity (IC) and expiration capacity (EC), and the nasal partitioning ratio (NPR) can be calculated. Practical measure the distance of nostril to ahead of the inferior turbinate and compare with DCAN. Make the correlational analysis on different index of three exam. RESULT: Reference values of acoustic rhinometry: MCA was (0.45 +/- 0. 16) cm2 for male, (0.44 +/- 0.16) cm2 for female; V2-5 was (3.52 +/- 1.38) cm3 for male, (3.36 +/- 1.22) cm3 for female, V5 was (5.10 +/- 1.47) cm3 for male, (4.86 +/- 1.12) cm3 for female; DCAN have two distance, (2.22 +/- 0.398, 0.53 +/- 0.625) cm was for male, (2.10 +/- 0.37, 0.67 +/- 0.15) cm was for female. No significant gender, side and age differences were shown in MCA, V5, V2-5. Significant gender differences were shown in DCAN but no side and age differences. Reference values of rhinomanometry: Significant gender but no side and age differences were shown in IR, ER, TIR, TER. Reference values of rhinospirometer: IC was (2.06 +/- 1.10) L/20 s for male, (1.37 +/- 0.34) L/20 s for female, EC was (2.15 +/- 1.23) L/20 s for male (1.39 +/- 0.58) L/20 s for female. NPRi was 0.11 [0.05, 0.23],NPRe was 0.11 [0.05, 0.19]. Significant gender but no side and age differences were shown in IC and EC. No gender and age differences were shown in NPRi and NPRe. There was significant correlation found between MCA and IR/ER/IC/EC, IR and IC, ER and EC, Rlr and NPRi/ NPRe. CONCLUSION: Acoustic rhinometry,rhinomanometry and rhinospirometer can be useful reference values to evaluate nasal ventilation function, more value will be found if use the three together.