Enhancing the endo-activity of the thermophilic chitinase to yield chitooligosaccharides with high degrees of polymerization.

Thermophilic endo-chitinases are essential for production of highly polymerized chitooligosaccharides, which are advantageous for plant immunity, animal nutrition and health. However, thermophilic endo-chitinases are scarce and the transformation from exo- to endo-activity of chitinases is still a challenging problem. In this study, to enhance the endo-activity of the thermophilic chitinase Chi304, we proposed two approaches for rational design based on comprehensive structural and evolutionary analyses. Four effective single-point mutants were identified among 28 designed mutations. The ratio of (GlcNAc)3 to (GlcNAc)2 quantity (DP3/2) in the hydrolysates of the four single-point mutants undertaking colloidal chitin degradation were 1.89, 1.65, 1.24, and 1.38 times that of Chi304, respectively. When combining to double-point mutants, the DP3/2 proportions produced by F79A/W140R, F79A/M264L, F79A/W272R, and M264L/W272R were 2.06, 1.67, 1.82, and 1.86 times that of Chi304 and all four double-point mutants exhibited enhanced endo-activity. When applied to produce chitooligosaccharides (DP ≥ 3), F79A/W140R accumulated the most (GlcNAc)4, while M264L/W272R was the best to produce (GlcNAc)3, which was 2.28 times that of Chi304. The two mutants had exposed shallower substrate-binding pockets and stronger binding abilities to shape the substrate. Overall, this research offers a practical approach to altering the cutting pattern of a chitinase to generate functional chitooligosaccharides.

Factors driving the implementation of the 'Local New Year' policy to prevent COVID-19 in China.

This study examines the contradiction caused by the 'local new year' policy, that is, the conflict between the pandemic prevention policies and people's emotional demands during the Spring Festival, based on the normalisation of pandemic prevention and control. It focuses on the scientific logical relationship with the contradiction that people voluntarily support 'local new year', to explore the primary driving factors of their willingness. By evaluating the migrant workers in large cities, the primary influencing factors were screened, and the primary dynamic factors and their relationship were obtained using the Logit logical selection model and maximum-likelihood estimation. The study identified, 'whether social and entertainment activities are planned in migrant cities', as the primary driving factor, followed by 'whether there are relatives (elderly /children) at home', and 'contracting the infection during travel'. In view of this conclusion, this study further proposes corresponding policy suggestions: Relevant measures should be adopted according to different regions and the current situation of the pandemic in combination with the characteristics of the episodic and local nature of the pandemic. 'Local new year' is encouraged from the perspective of enriching people's emotional needs for spiritual entertainment and care. This study provides a new perspective and theoretical basis for the research and formulation of policies related to the normalisation of pandemic prevention and control in China and worldwide, and has a certain practical reference value.

Investigation of the Relationship between CMYC Gene Polymorphisms and Glioma Susceptibility in Chinese Children.

Glioma is a common central nervous system tumors in children. CMYC has a range of functions that are disrupted in various tumor cells, and may contribute to the occurrence and development of glioma. Two CMYC single nucleotide polymorphisms (rs4645943C>T and rs2070583 A>G) were genotyped in 190 cases and 248 controls from Wenzhou and Guangzhou hospitals. After adjusting for age and sex, odds ratio and 95% confidence interval values were calculated by logistic regression to evaluate the correlation between CMYC gene polymorphisms and glioma risk; no significant associations were detected. These results require future validation in a larger sample cohort.

The association of miR34b/c and TP53 gene polymorphisms with Wilms tumor risk in Chinese children.

Wilms tumor is the most common pediatric malignancy in the kidney. The miR34b/c is a downstream target gene of the transcription factor p53. The important role of TP53 mutations, the methylation of miR34b/c, and the interaction between these two molecules in tumorigenesis have been well documented. Due to the biological connection between p53 and miR34b/c, in the present study, we investigated the association between polymorphisms in these two molecules and Wilms tumor susceptibility through genotyping two important functional polymorphisms (miR34b/c rs4938723 T>C and TP53 rs1042522 C>G) in 183 cases and 603 controls. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) derived from the logistic regression analysis were used to assess the correlation of miR34b/c rs4938723 and TP53 rs1042522 polymorphisms with Wilms tumor risk. Our results indicated that the association of miR34b/c rs4938723 and TP53 rs1042522 polymorphisms with Wilms tumor susceptibility was not statistically significant. Stratified analysis by age, gender, and clinical stage, as well as combined effect analysis were also performed, yet, no significant association was found. In conclusion, our study indicated a lack of association between the two selected polymorphisms and Wilms tumor susceptibility. Our findings need to be verified in studies with larger sample size in the future.

The association of RAN and RANBP2 gene polymerphisms with Wilms tumor risk in Chinese children.

Wilms tumor is considered to be the most common renal malignancy among children. RAN, a member of RAS superfamily, and its binding partner RANBP2 are related to the progression of multiple tumors. Nevertheless, the effects of the RAN and RANBP2 gene polymorphisms on the tumorigenesis of Wilms tumor remain unclarified. In this study, three potentially functional polymorphisms (rs56109543 C>T, rs7132224 A>G, and rs14035 C>T) in the RAN and one (rs2462788 C>T) in the RANBP2 were chosen to investigate their association with Wilms tumor susceptibility. Odds ratios (ORs) and 95% confidence intervals (CIs) were applied to assess the association of the selected polymorphisms with Wilms tumor susceptibility. Results shown that RAN rs7132224 AG/GG genotypes significantly increased Wilms tumor risk when compared to AA genotype (adjusted OR=1.40, 95% CI=1.01-1.95, P=0.047). Carriers of 1-3 risk genotypes have a significantly higher Wilms tumor risk than those without risk genotype (adjusted OR=1.49, 95% CI=1.07-2.07, P=0.020). Moreover, stratified analysis indicated that RAN rs56109543 CT/TT genotypes, RAN rs7132224 AG/GG genotypes and RANBP2 rs2462788 CT/TT genotypes remarkably increased Wilms tumor susceptibility among the subgroups. Our results indicated that RAN and RANBP2 polymorphisms were associated with Wilms tumor susceptibility in Chinese children. The role of RAN/RANBP2 in cancers deserves more attention.

A Fast and Efficient Measurement System for Nuclear Spin Relaxation Times in Atomic Vapors.

With the rapid progress of cutting-edge research such as quantum measurement technology, nuclear magnetic resonance (NMR) gyroscopes represent a major development direction of high-precision micro-miniature gyroscopes, which have significant advantages such as high precision, small size, and low power consumption. It is meaningful to measure the relaxation times of noble-gas atoms which are crucial indicators to accurately and quickly characterize the vapor cell performance as a core component of gyroscopes. In this paper, a test platform for relaxation time is built and an automatic relaxation time test system based on free induction decay (FID) and the π pulse method is designed to accelerate the relaxation time test. Firstly, the formula of the atomic dynamic process based on the Bloch equation was deduced, a GUI (Graphical User Interface) simulation based on the derived differential equation was conducted, and the moving process of the magnetic moment was visually described. Then, the virtual instrument was used to integrate multiple test instruments into an auto-test system, and LabVIEW programming was used for control to realize the automation of the test process on the test platform. Finally, the test results in different conditions were compared. The results show that the test system is stable and reliable with excellent man-machine interaction, and the measurement efficiency was increased by about 185%, providing an effective test scheme for vapor cell performance.

MYCN gene polymorphisms and Wilms tumor susceptibility in Chinese children.

BACKGROUND: Wilms tumor, derived from embryonic cells, accounts for a large proportion of pediatric renal tumors. MYCN encoded by MYCN proto-oncogene, a member of the MYC family, is a BHLH transcription factor. It plays a critical role in tumorigenesis and predicts poor clinical outcomes in various types of cancer. However, the role of MYCN remained unclarified in Wilms tumor. In this study, we investigated the association between MYCN gene polymorphisms and Wilms tumor susceptibility. METHODS: Four MYCN gene polymorphisms (rs57961569 G > A, rs9653226 T > C, rs13034994 A > G, and rs60226897 G > A) were genotyped in 183 cases and 603 controls. Adjusted odds ratios (AORs) and 95% confidence intervals (CIs) were calculated to evaluate the association between MYCN gene polymorphisms and Wilms tumor susceptibility. RESULTS: Overall, no significant association was found for any of the four MYCN gene polymorphisms. Interestingly, in the stratification analysis, the rs57961569 was found to be associated with decreased Wilms tumor susceptibility in the children older than 18 months (AOR = 0.65, 95% CI = 0.42-1.00, P = .050). Moreover, older children carrying 2-4 risk genotypes were at increased risk of Wilms tumor (OR = 1.55, 95% CI = 1.001-2.40, P = .0497). Haplotype GCAA was shown to significantly increased Wilms tumor risk (AOR = 2.40, 95% CI = 1.12-5.14, P = .024). CONCLUSION: Our study demonstrated that these MYCN gene polymorphisms might be low penetrant variants in Wilms tumor.