Identification of Vibrio alginolyticus virulent strain-specific DNA regions by suppression subtractive hybridization and PCR

AIMS

Vibrio alginolyticus was frequently isolated from diseased farmed fish in the coaster waters of Hainan Island over the past two decades. In this study, we attempted to identify candidates of virulent strain-specific DNA regions for this pathogen.

METHODS AND RESULTS

Suppression subtractive hybridization (SSH) and PCR were successively performed between the typical virulent strain and avirulent strain of V. alginolyticus, in which they shared 99·54% homology of 16S rDNAs. Out of 2873 subtracted clones, nine clones were finally indicated to harbour virulent strain-specific DNA fragments. The receivable functions of the major fragments in the nine clones were believed to encode methyl-accepting chemotaxis protein (n = 1), type VI secretion system-associated FHA domain protein TagH (n = 1), diguanylate cyclase (n = 1), AraC family transcriptional regulator (n = 1), ABC-type uncharacterized transport system permease component (n = 1) and hypothetical proteins (n = 4). Two hypothetical proteins contain several disordered regions.

CONCLUSIONS

Some specific DNA regions existed in the virulent strain of V. alginolyticus, and the SSH assay could be a highly sensitive method for identifying virulent regions in pathogens.

SIGNIFICANCE AND IMPACT OF THE STUDY

This report is the first to describe the identification of virulent strain-specific DNA regions in the V. alginolyticus genome, which is helpful in developing virulent strain-specific rapid detection methods and is a pivotal precondition for clarifying the molecular virulence mechanism of V. alginolyticus.

Protecting medical staff from skin injury/disease caused by personal protective equipment during epidemic period of COVID-19: experience from China

Linked articles: COVID‐19 SPECIAL FORUM. J Eur Acad Dermatol Venereol 2020; 34: e210–e216.

Association between dietary selenium intake and the prevalence of osteoporosis: a cross-sectional study

Objective

To examine the correlation between dietary selenium (Se) intake and the prevalence of osteoporosis (OP) in the general middle-aged and older population in China.

Methods

Data for analyses were collected from a population based cross-sectional study performed at the Xiangya Hospital Health Management Centre. Dietary Se intake was evaluated using a validated semi-quantitative food frequency questionnaire. OP was diagnosed on the basis of bone mineral density scans using a compact radiographic absorptiometry system. The correlation between dietary Se intake and the prevalence of OP was primarily examined by multivariable logistic regression.

Results

This cross-sectional study included a total of 6267 subjects (mean age: 52.2 ± 7.4 years; 42% women), and the prevalence of OP among the included subjects was 9.6% (2.3% in men and 19.7% in women). Compared with the lowest quartile, the energy intake, age, gender and body mass index (BMI)-adjusted odds ratios of OP were 0.72 (95% confidence interval [CI] 0.55–0.94), 0.72 (95% CI 0.51–1.01) and 0.47 (95% CI 0.31–0.73) for the second, third and fourth quartiles of dietary Se intake, respectively (P for trend = 0.001). The results remained consistent in male and female subjects. Adjustment for additional potential confounders (i.e., smoking status, drinking status, physical activity level, nutritional supplements, diabetes, hypertension, fibre intake, and calcium intake) did not cause substantial changes to the results.

Conclusions

In the middle-aged and older humans, participants with lower levels of dietary Se intake have a higher prevalence of OP in a dose-response manner.

Association between rs12742784 polymorphism and hip fracture, bone mineral density, and EPHB2 mRNA expression levels in elderly Chinese women

Objective: This study aimed to determine the association between rs12742784 polymorphism in the non-coding area and hip fracture, bone mineral density (BMD), and EPHB2 mRNA expression levels in elderly Chinese women.Methods: We investigated 250 Chinese women (mean age: 63.5 ± 8.3 years) including 123 hip fracture patients and 127 non-fracture controls. All participants underwent clinical examination to meet the inclusion criteria. Lumbar and hip BMD were detected by dual-energy X-ray absorptiometry. rs12742784 polymorphism was determined by restriction fragment length polymorphism and EPHB2 mRNA expression levels were measured by real-time polymerase chain reaction.Results: Distribution of rs12742784 genotypes agreed with Hardy-Weinberg equilibrium. The frequency of the CT + TT genotype was significantly associated with decreased risk of hip fracture (adjusted odds ratio = 0.57, p < 0.01) after adjusting for age and body mass index, and with increased BMD and EPHB2 mRNA expression levels. The T allele of the rs12742784 single nucleotide polymorphism (SNP) was a protective factor for hip fracture (adjusted odds ratio = 0.56, p < 0.01).Conclusion: rs12742784 polymorphism was associated with EPHB2 mRNA expression levels, BMD, and hip fracture in Chinese women. The T allele of the rs12742784 SNP was a protective factor for osteoporosis and hip fracture.

A Novel SCN9A Mutation (F826Y) in Primary Erythromelalgia Alters the Excitability of Nav1.7

BACKGROUND

Primary erythromelalgia (PE) is a dominant inherited disorder characterized by recurrent pain, redness, and warmth of the extremities that is caused by gain-of-function mutations in Nav1.7 encoding gene SCN9A. Most of the PE-causing mutations of Nav1.7 have been shown to be able to render Nav1.7-expressing cells hyperexcitable, however in most PE cases the symptoms are refractory to treatment with sodium channel blockers and the mechanism underlying the intractability has not been clearly clarified.

OBJECTIVE

To identify the mutation of SCN9A in a Chinese Han family with typical symptoms of PE and study the electrophysiological effect of the identified mutation.

METHODS

A Chinese Han family with typical symptoms of PE was collected and the proband's response to treatment was recorded. All the exons and flanking intronic sequences of SCN9A were amplified with PCR and sequenced. Several online programs were used to predict the damaging effect of variants. The functional effect of variants was studied by voltage-clamp analysis in CHO-K1 cells.

RESULTS

The PE symptoms of the proband are refractory to all kinds of reported medications. Sequence analysis of SCN9A showed that a novel c.2477T>A (p. F826Y) mutation co-segregated with the disease phenotype. Several online programs predicted that the F826Y mutation has a deleterious effect on the gene product. Voltage-clamp analysis showed that while compared with the wild-type channel, activation of the F826Y mutant channel was shifted by 7.7 mV in a hyperpolarizing direction, whereas steadystate inactivation was shifted by 4.3 mV in a depolarizing direction.

CONCLUSION

A novel disease-causing SCN9A Mutation (F826Y) was identified in a Chinese family with typical PE symptoms refractory to treatment. F826Y of Nav1.7 could render DRG neurons hyperexcitable, contributing to the pathogenesis of PE.

Thermodynamic method for establishment of relationship between icephobicity/superhydrophobicity and microstructure-Based on computing for adhesion work

Superhydrophobic surfaces (SHS) have potential in solving the icing of aircraft, high-voltage overhead transmission lines, and other power network devices exposed to the air. For this reason, we wish to establish the relationship between microstructure and the adhesion work by thermodynamic method, also for analysis of the relationship between the hydrophobicity and icephobicity (or anti-icing). Therefore, respectively considering Cassie-Baxter and Wenzel states, such relationship was theoretically established based on one/two-step surface model, enlightened by natural and artificial SHS. Among it, how to obtain the adhesion work of icing per unit ice-solid interface is the key to this study. Followed by it, hydrothermal experiment, chemical deposition, and etching methods were performed to verify our theoretical results.

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How to model for the SHS based on the natural and artificial SHS;

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Computation for adhesion work (w_aw) per unit area of a water droplet–SHS interface;

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Computation for adhesion work (w_ai) per unit area of a frozen water droplet–SHS interface;

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Computation for reduced adhesion work (w_a2) after icing;

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Hydrothermal experiment, chemical deposition and etching methods were used for validation of modeling.

The earliest human occupation of the high-altitude Tibetan Plateau 40 thousand to 30 thousand years ago

The Tibetan Plateau is the highest and one of the most demanding environments ever inhabited by humans. We investigated the timing and mechanisms of its initial colonization at the Nwya Devu site, located nearly 4600 meters above sea level. This site, dating from 40,000 to 30,000 years ago, is the highest Paleolithic archaeological site yet identified globally. Nwya Devu has yielded an abundant blade tool assemblage, indicating hitherto-unknown capacities for the survival of modern humans who camped in this environment. This site deepens the history of the peopling of the "roof of the world" and the antiquity of human high-altitude occupations more generally.

[Meta-analysis of voice outcomes after steroid injection on benign vocal fold lesions]

Objective:The aim of this study is to perform a meta-analysis of vocal changes after vocal cord steroid injection (VFSI) in the treatment of benign lesions. Method:Pubmed, Embase, CNKI and Wanfang database were searched using the keywords. A total of 7 articles were characterized based on our keyword search. The chi-square-based I² statistic test was employed to assess the between-study heterogeneity. Additionally, random effects models were used to calculate mean differences with 95% confidence intervals. Result:A total of 344 cases were included in 7 literatures. Meta-analysis demonstrated a significant increase in maximal phonation time(MPT) and decrease Jitter after VFSI.The index and amplitude perturbations were not statistically significant before and after hormone injection. Conclusion:Our results support that VFSI has advantages in terms of voice quality. However, we need more studies with longer follow-up periods to validate our findings.

Threshold Maps for Inclusion-Initiated Micro-Cracks and White Etching Areas in Bearing Steel: The Role of Impact Loading and Surface Sliding

Wind turbine gearbox (WTG) bearings can fail prematurely, significantly affecting wind turbine operational availability and the cost of energy production. The current most commonly accepted theory of failure mechanism is that the bearing subsurface is weakened by white etching crack (WEC) networks that eventually lead to the flaking away of material from the bearing surface. Subsurface damage due to rolling contact fatigue (RCF) is thought to be the main cause of premature failure, resulting from the initiation of micro-cracks, often at non-metallic inclusions or other material defects, which then propagate to the bearing surface. This study proposes a hypothesis that impact loading together with high levels of surface traction and contact pressure are important factors contributing to the initiation of micro-cracks and white etching areas (WEAs) at non-metallic inclusions which may lead to the formation of WEC networks. Both repeated impact and twin-disc RCF tests were designed to investigate inclusion-initiated micro-cracks and WEAs at subsurface in order to test this hypothesis. This led to the recreation of inclusion-initiated micro-cracks and WEAs in tested specimens, similar to the subsurface damage observed at inclusions in failed WTG bearing raceways. Tests were carried out to determine threshold levels of contact pressure, surface traction, and impact loading required for the formation of inclusion-initiated micro-cracks and WEAs.

Nicotinamide N-methyltransferase as a potential marker for cancer

Cancer is the main leading cause of death in the world, although it has been made noteworthy advances in cancer research in the past decades. Early detection of cancer is extremely important in improving the chances of successful therapy. Thus, it is urgently needed to make further efforts to explore novel tumor markers for treatment. Nicotinamide N-methyltransferase (NNMT) is a cytosolic enzyme which catalyzes the N-methylation of nicotinamide to form 1-methylnicotinamide (1-MNA), and plays an important role in controlling the intracellular concentration of nicotinamide. Nicotinamide, the precursor to NAD+, is an important cofactor that associates cellular redox states with energy metabolism. Growing evidence shows that NNMT protein levels are elevated in a variety of human cancers, and increased NNMT expression has been linked to tumor aggressiveness. This paper presents a review for the role of NNMT expressed in a series of human cancers and the regulating mechanism involved, and offers its potential value of NNMT in cancer detection and treatment.

A pleiotropic effect of the APOE gene: association of APOE polymorphisms with multibacillary leprosy in Han Chinese from Southwest China

BACKGROUND

Patients with leprosy have a very low risk of Alzheimer disease (AD) and β-amyloid (Aβ) deposition is significantly lower in the brain tissue of elderly patients with leprosy compared with age-matched controls. Apolipoprotein E (ApoE) plays a critical role in lipid metabolic pathways and in the brain, facilitating the proteolytic clearance of Aβ. We hypothesized that APOE confers risk of leprosy as lipid metabolism is involved in Mycobacterium leprae infection.

OBJECTIVES

To investigate the potential genetic associations between APOE and leprosy in two independent Chinese case-control cohorts from the Yuxi and Wenshan prefectures, Yunnan Province of Southwest China.

METHODS

Five APOE single-nucleotide polymorphisms (SNPs) were analysed in 1110 individuals (527 patients and 583 controls) from the Yuxi prefecture using a SNaPshot assay. Genetic variations in the entire APOE exons were screened in 1788 individuals (798 patients and 990 controls) from the Wenshan prefecture using next-generation sequencing technology.

RESULTS

The AD-associated SNPs rs405509 and rs439401 increased the risk of leprosy per se and multibacillary leprosy (P < 0·005), but the APOE-ε4 allele did not. The SNPs rs405509 and rs439401 were cis expression quantitative trait loci (eQTL) for APOE expression in human skin. Differential APOE mRNA expression was observed in skin lesions of patients with type I reaction leprosy and those with multibacillary leprosy. APOE and related lipid genes are involved in an interaction network with leprosy susceptibility genes.

CONCLUSIONS

The APOE gene is associated with leprosy, most likely by regulating lipid-metabolism-related genes.