Long-term exposure to ozone and sleep disorders in children: A multicity study in China.

Evidence regarding the link between long-term ambient ozone (O3) exposure and childhood sleep disorders is little. This study aims to examine the associations between long-term exposure to O3 and sleep disorders in children. We conducted a population-based cross-sectional survey, including 185,428 children aged 6-18 years in 173 schools across 14 Chinese cities during 2012 and 2018. Parents or guardians completed a checklist using Sleep Disturbance Scale for Children, and O3 exposure at residential and school addresses was estimated using a satellite-based spatiotemporal model. We used generalized linear mixed models to test the associations with adjustment for factors including socio-demographic variables, lifestyle, meteorology and multiple pollutants. Mean concentrations of O3, particulate matter with diameters ≤2.5 mm (PM2.5) and nitrogen dioxide (NO2) were 89.0 µg/m3, 42.5 µg/m3 and 34.4 µg/m3, respectively. O3 and NO2 concentrations were similar among provinces, while PM2.5 concentration varied significantly among provinces. Overall, 19.4% of children had at least one sleep disorder. Long-term exposure to O3 was positively associated with odds of sleep disorders for all subtypes. For example, each interquartile increment in home-school O3 concentrations was associated with a higher odds ratio for global sleep disorder, at 1.22 (95% confidence interval: 1.18, 1.26). Similar associations were observed for sleep disorder subtypes. The associations remained similar after adjustment for PM2.5 and NO2. Moreover, these associations were heterogeneous regionally, with more prominent associations among children residing in southeast region than in northeast and northwest regions in China. We concluded that long-term exposure to O3 is positively associated with risks of childhood sleep disorders. These associations varied by geographical region of China.

Global, regional, and national burden of ischemic heart disease attributable to ambient PM2.5 from 1990 to 2019: An analysis for the global burden of disease study 2019.

Information on the spatio-temporal patterns of the burden of ischemic heart disease (IHD) caused by ambient ambient fine particulate matter (PM2.5) in the global level is needed to prioritize the control of ambient air pollution and prevent the burden of IHD. The Global Burden of Disease Study (GBD) 2019 provides data on IHD attributable to ambient PM2.5. The IHD burden and mortality attributable to ambient PM2.5 were analyzed by year, age, gender, socio-demographic index (SDI) level, geographical region and country. Estimated annual percentage change (EAPC) was calculated to estimate the temporal trends of age-standardized mortality rate (ASMR) and age-standardized disability-adjusted life years rate (ASDR) from 1990 to 2019. Globally, the ASMR and ASDR for ambient PM2.5-related IHD tended to level off generally, with EAPC of -0.03 (95% CI: -0.06, 0.12) and 0.3 (95% CI: 0.22, 0.37), respectively. In the past 30 years, there were obvious differences in the trend of burden change among different regions. A highest increased burden was estimated in low-middle SDI region (EAPC of ASMR: 3.73 [95% CI: 3.56, 3.9], EAPC of ASDR: 3.83 [95% CI: 3.64, 4.02]). In contrast, the burden in high SDI region (EAPC of ASMR: -4.48 [95% CI: -4.6, -4.35], EAPC of ASDR: -3.98 [95% CI: -4.12, -3.85]) has declined most significantly. Moreover, this burden was higher among men and older populations. EAPCs of the ASMR (R = -0.776, p < 0.001) and ASDR (R = -0.781, p < 0.001) of this burden had significant negative correlations with the countries' SDI level. In summary, although trends in the global burden of IHD attributable to ambient PM2.5 are stabilizing, but this burden has shifted from high SDI countries to middle and low SDI countries, especially among men and elderly populations. To reduce this burden, the air pollution management prevention need to be further strengthened, especially among males, older populations, and middle and low SDI countries.

Efficacy of mouthwash on reducing salivary SARS-CoV-2 viral load and clinical symptoms: a systematic review and meta-analysis.

BACKGROUND: COVID-19 has been a public health emergency of international concern (PHEIC) for a lengthy period of time. The novel coronavirus is primarily spread via aerosols at a short distance, with infected individuals releasing large amounts of aerosols when speaking and coughing. However, there is an open question regarding whether mouthwash could effectively reduce virus transmission during the COVID-19 pandemic and support the prevention of infection among medical workers. METHODS: Cochrane Library, PubMed, Web of Science, and Embase databases were systematically searched from the inception of each database to January 12, 2023 for currently available randomized clinical trials (RCTs) on the effect of mouthwash on novel coronavirus load in the oral cavity in COVID-19 patients. The treatment group received mouthwash for rinsing the mouth, while the control group received a placebo or distilled water for COVID-19 patients. The primary outcomes were CT value and viral load. Odds ratios (ORs) were estimated using a random-effects model. Subgroup and sensitivity analyses were performed to minimize the bias and the impact of heterogeneity. RESULTS: Thirteen RCTs were included. Seven studies reported the intervention effect of mouthwash on the CT value of novel coronavirus. The analysis results showed that the mouthwash group had a positive impact on the CT value of novel coronavirus [ SMD = 0.35, 95% CI (0.21, 0.50)] compared with the control group. In addition, subgroup analysis showed a significant positive effect of mouthwash on CT values in the treatment group compared with the control group, with chlorhexidine (CHX) [SMD = 0.33, 95% CI (0.10, 0.56)], povidone-iodine (PVP-I) [SMD = 0.61, 95% CI (0.23, 0.99)], or hydrogen peroxide (HP) [SMD = 1.04, 95% CI (0.30, 1.78)] as an ingredient of the mouthwash. Six studies reported the intervention effect of mouthwash on the viral load, 263 cases in the treatment group and 164 cases in the control group. The analysis results showed that there was no statistical difference between the mouthwash group and the control group in the viral load of novel coronavirus [SMD = -0.06, 95% CI (-0.18, 0.05)]. In the subgroup analysis by measurement time, there were statistically significant differences between the mouthwash and control groups for CT values [SMD = 0.52, 95% CI (0.31, 0.72)] and viral load [SMD = - 0.32, 95% CI (- 0.56, - 0.07)] within 30 min of gargling. CONCLUSIONS: In summary, mouthwash has some efficacy in reducing the viral load of novel coronavirus, especially within 30 min after rinsing the mouth. Mouthwash containing CHX, PVP-I and HP all had significant positive effects on CT values, and PVP-I-containing mouthwash may be a promising option to control novel coronavirus infections and relieve virus-related symptoms. However, studies on the dose and frequency of use of mouthwash for infection control are still lacking, which may limit the clinical application of mouthwash. TRIAL REGISTRATION: Protocol registration: The protocol was registered at PROSPERO (CRD42023401961).

Optimization of single-tube nested PCR for the detection of Echinococcus spp.

Echinococcosis is a serious zoonotic life-threatening parasitic disease caused by metacestodes of Echinococcus spp., and appropriate sensitive diagnosis and genotyping techniques are required to detect infections and study the genetic characterization of Echinococcus spp. isolates. In this study, a single-tube nested PCR (STNPCR) method was developed and evaluated for the detection of Echinococcus spp. DNA based on the COI gene. STNPCR was 100 times more sensitive than conventional PCR and showed the same sensitivity to common nested PCR (NPCR); but with a lower risk of cross-contamination. The limit of detection of the developed STNPCR method was estimated to be 10 copies/µL of the recombinant standard plasmids of Echinococcus spp. COI gene. In clinical application, 8 cyst tissue samples and 12 calcification tissue samples were analysed by conventional PCR with outer and inner primers and resulted in 100.00% (8/8) and 8.33% (1/12), 100.00% (8/8) and 16.67% (2/12) positive reactions, respectively, while STNPCR and NPCR were all able to identify the presence of genomic DNA in 100.00% (8/8) and 83.33% (10/12) of the same samples. Due to its high sensitivity combined with the potential for the elimination of cross-contamination, the STNPCR method was suitable for epidemiological investigations and characteristic genetic studies of Echinococcus spp. tissue samples. The STNPCR method can effectively amplify low concentrations of genomic DNA from calcification samples and cyst residues infected with Echinococcus spp. Subsequently, the sequences of positive PCR products were obtained, which were useful for haplotype analysis, genetic diversity, and evolution studies of Echinococcus spp., and understanding of Echinococcus spp. dissemination and transmission among the hosts.

Identification and prevalence of fluke infection in yak and Tibetan sheep around Qinghai Lake, China.

Liver flukes (Fasciola spp.) and rumen flukes (Paramphistomum spp.) are significant parasites in livestock worldwide, and Fasciola spp. are considered an important zoonotic parasite. To our knowledge, there are no reports on fluke species identification and epidemiological prevalence in yak and Tibetan sheep around Qinghai Lake, China. Therefore, this study aimed to identify the major fluke species and determine the prevalence of fluke infections among yak and Tibetan sheep in this area. A total of 307 fecal samples were collected and fluke eggs identified using morphology and molecular methods. Our study is the first to display that the predominant fluke species were F. hepatica and P. leydeni in yak and Tibetan sheep around Qinghai Lake. The overall prevalence of fluke infections in yak and Tibetan sheep was 57.7% (177/307). Specifically, the prevalences of F. hepatica and P. leydeni were 15.0% (46/307) and 31.6% (97/307), respectively, and the co-infection of both species was 11.1% (34/307). No significant difference existed in the prevalence of overall fluke infection between yak and Tibetan sheep (p < 0.05). However, F. hepatica prevalence was significantly different in yak and Tibetan sheep (p < 0.05) but not P. leydeni. The findings of this study provide useful information about the current status of natural fluke invasion in yak and Tibetan sheep around Qinghai Lake, which could be important for monitoring and controlling these parasites in the region.

Genome-wide phylogenetic and genetic evolutionary analyses of mitochondria in Hypoderma bovis and H. sinense on the Qinghai-Tibetan Plateau.

Hypoderma bovis (H. bovis) and Hypoderma sinense (H. sinense) are insects that cause hypodermosis in yaks and Bos taurus. Hypodermosis is a severe skin condition that not only impairs the development of local animal husbandry but also poses threats to human health as a zoonosis. The Qinghai-Tibetan Plateau (QTP) is known as the "Roof of the World." Its unique geographical environment and climate conditions have supported the growth of a wide range of mammals, providing favorable conditions for Hypoderma spp. to complete their life cycles. In this study, the whole mitochondrial genomes of H. bovis and H. sinense collected from the QTP were sequenced and phylogenetically analyzed. We found that the whole genomes of H. bovis and H. sinense are 16,283 bp and 16,300 bp in length, respectively. Both the H. bovis and H. sinense genomes have 37 mitochondrial genes, which include two rRNA genes (16S rRNA and 12S rRNA), 22 tRNA genes, the control region (D-loop region), the light chain replication initiation region, and 13 protein-coding genes (PCGs). The phylogenetic tree generated based on the 13 PCGs revealed close phylogenetic relationships between H. sinense, H. bovis, and Hypoderma lineatum. A similar result was also found in our phylogenetic analysis based on 18S rRNA and 28S rRNA. However, analysis of cytochrome oxidase subunit I (COI) showed cluster of H. bovis, H. sinense, and Cuterebra spp. on the same branch, all belonging to Oestridae. The differentiation time generated based on 13 PCGs indicates that H. bovis and H. sinense differentiated and formed ~4.69 million years ago (Mya) and ~4.06 Mya, respectively. This timing coincides with the differentiation and appearance of yak and Bos taurus in the Pliocene (~4.7 Mya), indicating that the parasites and mammals diverged in close temporal proximity. Of note, this period also witnessed a rapid uplift of the QTP, causing significant climate and environmental changes. Thus, we conjecture that the differentiation of Hypoderma spp. is potentially related to the differentiation of their host species, as well as climate changes caused by the uplift of the QTP. Overall, our study can provide valuable data to support further studies on the phylogeny and differentiation of Hypoderma spp. on the QTP.

A Study of Two Novel Techniques for One-stage Closure of Chronic Oroantral Fistula and Sinus Floor Lift.

PURPOSE: This study aimed to compare two novel techniques for chronic oroantral fistula (OAF) closure combined with maxillary sinus floor elevation. MATERIALS AND METHODS: Ten patients who had implant installation needs but suffered from a chronic OAF were enrolled in the study from January 2016 to June 2021. The technique applied involved OAF closure and simultaneous sinus floor elevation by either a transalveolar or lateral window approach. Bone graft material evaluation results, postoperative clinical symptoms and complications were compared between the two groups. Student's t -test and χ 2 test were used to analyze the results. RESULTS: In this study, 5 patients with a chronic OAF were treated with the transalveolar approach (group I), and 5 were treated with the lateral window approach (group II). The alveolar bone height was significantly higher in group II than in group I ( P ＜0.001). The pain at 1 day ( P =0.018) and 3 days ( P =0.029) postoperatively and facial swelling at 7 days ( P =0.016) postoperatively were obviously greater in group II than in group I. There were no severe complications in either group. CONCLUSIONS: The techniques combined OAF closure with sinus lifting to reduce surgical frequency and risks. The transalveolar approach resulted in milder postoperative reactions, but the lateral approach could provide more bone volume.

[Progress in Application of Concentrated Growth Factor in Oral Tissue Regeneration].

Tissue regeneration is an important engineering method for the treatment of oral soft and hard tissue defects.Growth factors,as one of the three elements of tissue regeneration,are a necessary condition for tissue regeneration.Concentrated growth factor(CGF)is a new generation of blood extract prepared by changing the centrifugal speed on the basis of the preparation of platelet-rich plasma(PRP)and platelet-rich fibrin(PRF).It contains abundant growth factors and a fibrin matrix with a three-dimensional network structure,being capable of activating angiogenesis and promoting tissue regeneration and healing.CGF has been widely used in the repair and regeneration of oral soft and hard tissues.This paper introduces the preparation and composition of CGF and reviews the application of CGF in oral implantation and the regeneration of oral bone tissue,periodontal tissue,and dental pulp tissue.

Effect of therapeutic versus prophylactic anticoagulation therapy on clinical outcomes in COVID-19 patients: a systematic review with an updated meta-analysis.

BACKGROUND: Previous studies demonstrate a reduced risk of thrombosis and mortality with anticoagulant treatment in patients with COVID-19 than in those without anticoagulation treatment. However, an open question regarding the efficacy and safety of therapeutic anticoagulation (T-AC) versus a lower dose, prophylaxis anticoagulation (P-AC) in COVID-19 patients is still controversial. METHODS: We systematically reviewed currently available randomized clinical trials (RCTs) and observational studies (OBs) from January 8, 2019, to January 8, 2022, and compared prophylactic and therapeutic anticoagulant treatment in COVID-19 patients. The primary outcomes were risk of mortality, major bleeding, and the secondary outcomes included venous and arterial thromboembolism. Subgroup analysis was also performed between critically ill and non-critically ill patients with COVID-19 and between patients with higher and lower levels of D-dimer. Sensitivity analysis was performed to decrease the bias and the impact of population heterogeneity. RESULTS: We identified 11 RCTs and 17 OBs fulfilling our inclusion criteria. In the RCTs analyses, there was no statistically significant difference in the relative risk of mortality between COVID-19 patients with T-AC treatment and those treated with P-AC (RR 0.95, 95% CI, 0.78-1.15, P = 0.60). Similar results were also found in the OBs analyses (RR 1.21, 95% CI, 0.98-1.49, P = 0.08). The pooling meta-analysis using a random-effects model combined with effect sizes showed that in the RCTs and OBs analyses, patients with COVID-19 who received T-AC treatment had a significantly higher relative risk of the major bleeding event than those with P-AC treatment in COVID-19 patients (RCTs: RR 1.76, 95% CI, 1.19-2.62, P = 0.005; OBs: RR 2.39, 95% CI, 1.56-3.68, P < 0.0001). Compared with P-AC treatment in COVID-19 patients, patients with T-AC treatment significantly reduced the incidence of venous thromboembolism (RR 0.51, 95% CI, 0.39-0.67, P<0.00001), but it is not associated with arterial thrombosis events (RR 0.97, 95% CI, 0.66-1.42, P = 0.87). The subgroup analysis of OBs shows that the mortality risk significantly reduces in critically ill COVID-19 patients treated with T-AC compared with those with P-AC treatment (RR 0.58, 95% CI, 0.39-0.86, P = 0.007), while the mortality risk significantly increases in non-critically ill COVID-19 patients treated with T-AC (RR 1.56, 95% CI, 1.34-1.80, P < 0.00001). In addition, T-AC treatment does not reduce the risk of mortality in COVID-19 patients with high d-dimer levels in RCTs. Finally, the overall sensitivity analysis after excluding two RCTs studies remains consistent with the previous results. CONCLUSIONS: In our integrated analysis of included RCTs and OBs, there is no significant difference between the mortality of T-AC and P-AC treatment in unselected patients with COVID-19. T-AC treatment in COVID-19 patients significantly reduced the incidence of venous thromboembolism but showed a higher risk of bleeding than those with P-AC treatment. In addition, P-AC treatment was superior to T-AC treatment in non-critically ill COVID-19 patients, the evidence supporting the necessity for T-AC treatment in critically ill COVID-19 patients came only from OBs. TRIAL REGISTRATION: Protocol registration: The protocol was registered at PROSPERO (CRD42021293294).

Improved morbidity-based air quality health index development using Bayesian multi-pollutant weighted model.

BACKGROUND: The widely used Air Quality Index (AQI) has been criticized due to its inaccuracy, leading to the development of the air quality health index (AQHI), an improvement on the AQI. However, there is currently no consensus on the most appropriate construction strategy for the AQHI. OBJECTIVES: In this study, we aimed to evaluate the utility of AQHIs constructed by different models and health outcomes, and determine a better strategy. METHODS: Based on the daily time-series outpatient visits and hospital admissions from 299 hospitals (January 2016-December 2018), and mortality (January 2017-December 2019) in Guangzhou, China, we utilized cumulative risk index (CRI) method, Bayesian multi-pollutant weighted (BMW) model and standard method to construct AQHIs for different health outcomes. The effectiveness of AQHIs constructed by different strategies was evaluated by a two-stage validation analysis and examined their exposure-response relationships with the cause-specific morbidity and mortality. RESULTS: Validation by different models showed that AQHI constructed with the BMW model (BMW-AQHI) had the strongest association with the health outcome either in the total population or subpopulation among air quality indexes, followed by AQHI constructed with the CRI method (CRI-AQHI), then common AQHI and AQI. Further validation by different health outcomes showed that AQHI constructed with the risk of outpatient visits generally exhibited the highest utility in presenting mortality and morbidity, followed by AQHI constructed with the risk of hospitalizations, then mortality-based AQHI and AQI. The contributions of NO2 and O3 to the final AQHI were prominent, while the contribution of SO2 and PM2.5 were relatively small. CONCLUSIONS: The BMW model is likely to be more effective for AQHI construction than CRI and standard methods. Based on the BMW model, the AQHI constructed with the outpatient data may be more effective in presenting short-term health risks associated with the co-exposure to air pollutants than the mortality-based AQHI and existing AQIs.

Two PAAR Proteins with Different C-Terminal Extended Domains Have Distinct Ecological Functions in Myxococcus xanthus.

Bacterial proline-alanine-alanine-arginine (PAAR) proteins are located at the top of the type VI secretion system (T6SS) nanomachine and carry and deliver effectors into neighboring cells. Many PAAR proteins are fused with a variable C-terminal extended domain (CTD). Here, we report that two paar-ctd genes (MXAN_RS08765 and MXAN_RS36995) located in two homologous operons are involved in different ecological functions of Myxococcus xanthusMXAN_RS08765 inhibited the growth of plant-pathogenic fungi, while MXAN_RS36995 was associated with the colony-merger incompatibility of M. xanthus cells. These two PAAR-CTD proteins were both toxic to Escherichia coli cells, while MXAN_RS08765, but not MXAN_RS36995, was also toxic to Saccharomyces cerevisiae cells. Their downstream adjacent genes, i.e., MXAN_RS08760 and MXAN_RS24590, protected against the toxicities. The MXAN_RS36995 protein was demonstrated to have nuclease activity, and the activity was inhibited by the presence of MXAN_RS24590. Our results highlight that the PAAR proteins diversify the CTDs to play divergent roles in M. xanthusIMPORTANCE The type VI secretion system (T6SS) is a bacterial cell contact-dependent weapon capable of delivering protein effectors into neighboring cells. The PAAR protein is located at the top of the nanomachine and carries an effector for delivery. Many PAAR proteins are extended with a diverse C-terminal sequence with an unknown structure and function. Here, we report two paar-ctd genes located in two homologous operons involved in different ecological functions of Myxococcus xanthus; one has antifungal activity, and the other is associated with the kin discrimination phenotype. The PAAR-CTD proteins and the proteins encoded by their downstream genes form two toxin-immunity protein pairs. We demonstrated that the C-terminal diversification of the PAAR-CTD proteins enriches the ecological functions of bacterial cells.

Exposure to second-hand smoke during early life and subsequent sleep problems in children: a population-based cross-sectional study.

BACKGROUND: Previous studies have revealed that current secondhand smoke exposure showed highly suggestive evidence for increased risk of simultaneous sleep problems in children. Data on the associations between early-life exposure to SHS with subsequent sleep problems in children were scarce. We aimed to evaluate the associations of early-life SHS exposure with sleep problems in children. METHODS: In this cross-sectional study, children were recruited from elementary and middle schools in Liaoning Province, China between April 2012 and January 2013. We assessed early-life SHS exposure (pregnancy and the first 2 years of life) via questionnaires. Sleep problems and different types of sleep-related symptoms were measured based on the validated tool of the Sleep Disturbance Scale for Children (SDSC). Generalized linear mixed models were applied to estimate the associations of early-life SHS exposure with sleep problems. RESULTS: We included a total of 45,562 children (22,657 [49.7%] males; mean [SD] age, 11.0 [2.6] years) and 6167 of them (13.5%) were exposed to early-life SHS during both pregnancy and the first 2 years of life. Compared with unexposed counterparts, children exposed to early-life SHS had higher total T-scores of SDSC (ß = 4.32; 95%CI: 4.06, 4.58) and higher odds of increased sleep problems (OR = 2.14; 95%CI: 1.89, 2.42). When considering different sleep-related symptoms, the associations between early-life SHS exposure and symptom of sleep-wake transition disorders (i.e., bruxism) were the strongest in all analyses. CONCLUSIONS: Early-life SHS exposure was associated with higher odds of global sleep problems and different sleep-related symptoms in children aged 6-18 years. Our findings highlight the importance to strengthen efforts to support the critical importance of maintaining a smoke-free environment especially in early life.

Quantitative Segmentation Analysis of the Radiological Changes by Using ITK-SNAP: Risk Assessment of the Severity and Recurrence of Medication-related Osteonecrosis of the Jaw.

Background and purpose: Medication-related osteonecrosis of the jaw (MRONJ) severely impairs patients' quality of life and is remarkably refractory to treatment. There are lots of studies about identification of the radiographic features of MRONJ, yet reports about quantitative radiographic analysis for the risk assessment of the severity and recurrence of MRONJ are rarely heard. The aim of this study was to investigate the volumes of osteolytic lesions and radiodensity values of osteosclerotic lesions in MRONJ patients by using ITK-SNAP for severity prediction and prognosis evaluation. Materials and methods: Of 78 MRONJ patients (78 lesions) involved in this retrospective study, 53 were presented as osteolytic lesions and 25 were presented as osteosclerotic changes alone. Comprehensive CBCT images, demographics and clinical data of patients were investigated. The volumetric analysis and radiodensity measurement were performed by ITK-SNAP. SPSS 25.0 were used for statistical analysis. Results: The osteolytic lesion volumes in MRONJ patients receiving intravenous bisphosphonates (P=0.004) and patients without osteoporosis (P=0.027) were significantly large. No significant correlation between the volumes and bisphosphonates duration was found (P=0.094). The radiodensity values of osteosclerotic lesions was significantly correlated with bisphosphonates duration (P=0.040). The surrounding area of post-surgical lesions in MRONJ patients with recurrence showed significantly great radiodensity values (P=0.025). No significant correlation between the radiodensity values and the transformation from osteosclerotic lesions to osteolytic lesions was observed (P=0.507). Conclusion: MRONJ patients receiving intravenous bisphosphonates develop into large volumes of osteolytic lesions more easily. Long-term bisphosphonates duration is possibly related with higher bone density of osteosclerotic lesions, while higher density is not associated with the transformation from osteosclerotic lesions to osteolytic lesions. A rise of bone mineral density nearby post-surgical lesions is probably a predictor for MRONJ recurrence.

Deinococcus terrestris sp. nov., a gamma ray- and ultraviolet-resistant bacterium isolated from soil.

Strain SDU3-2T was isolated from a soil sample collected in Shandong Province, PR China. Cells of SDU3-2T were spherical, Gram-stain-positive, aerobic and non-motile. Cellular growth of the strain occurred at 25-45 °C, pH 5.5-8.5 and with 0-1.5 % (w/v) of NaCl. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strain SDU3-2T was closest to the type strain Deinococcus murrayi ALT-1bT with a similarity of 95.2 %. The draft genome was 3.49 Mbp long with 69.2 mol% G+C content. Strain SDU3-2T exhibited high resistance to gamma radiation (D10 >12 kGy) and UV (D10 >900 J m-2). The strain encoded many genes for resistance to radiation and oxidative stress, which were highly conserved with other Deinococcus species, but possessed interspecific properties. The major fatty acids of SDU3-2T cells were C15 : 1 ω6c, C16 : 1 ω7c/C16 : 1 ω6c, and C17 : 1 ω8c, the major menaquinone was menaquinone-8, and the major polar lipids were an unidentified phosphoglycolipid, four unidentified glycolipids and an unidentified phospholipid. The average nucleotide identity and DNA-DNA hybridization results further indicated that strain SDU3-2T represents a new species in the genus Deinococcus, for which the name Deinococcus terrestris sp. nov. is proposed. The type strain is SDU3-2T (=CGMCC 1.17147T=KCTC 43098T).

Psychroflexus aurantiacus sp. nov., isolated from soil in the Yellow River Delta wetlands.

A Gram-stain-negative, strictly aerobic, non-motile, orange-coloured bacterium, designated YR1-1T, was isolated from a soil sample collected from the Yellow River Delta wetlands (PR China). Growth was observed at a salinity of 1.0-15.0 % NaCl, 4-45 °C and pH 6.0-9.0. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that YR1-1T represented a member of the genus Psychroflexus, with the highest sequence similarity to Psychroflexus sediminis YIM-C238T (97.9 %), followed by Psychroflexus aestuariivivens (97.1 %) and Psychroflexus torquis (96.4 %). The average nucleotide identity and digital DNA-DNA hybridization values between YR1-1T and other closely related type strains of species of the genus Psychroflexus were 68.7-86.3% and 17.8-30.9 %. The genome of the strain was 2 899 374 bp in length with 39.8 % DNA G+C content. The predominant fatty acids (>10 %) were iso-C15 : 0 and anteiso-C15 : 0. The major respiratory quinone was menaquinone-6 (MK-6) and the major polar lipids were phosphatidylethanolamine, phospholipid, diphosphatidylglycerol, two unidentified aminolipids and four unidentified lipids. The combined genotypic and phenotypic data indicate that YR1-1T represents a novel species within the genus Psychroflexus, for which the name Psychroflexus aurantiacus sp. nov., is proposed. The type strain is YR1-1T (=KCTC 72794T=CGMCC 1.17458T).

Whole transcriptome analysis and gene deletion to understand the chloramphenicol resistance mechanism and develop a screening method for homologous recombination in Myxococcus xanthus.

BACKGROUND: Myxococcus xanthus DK1622 is a model system for studying multicellular development, predation, cellular differentiation, and evolution. Furthermore, it is a rich source of novel secondary metabolites and is widely used as heterologous expression host of exogenous biosynthetic gene clusters. For decades, genetic modification of M. xanthus DK1622 has mainly relied on kanamycin and tetracycline selection systems. RESULTS: Here, we introduce an alternative selection system based on chloramphenicol (Cm) to broaden the spectrum of available molecular tools. A chloramphenicol-resistant growth phase and a chloramphenicol-susceptible growth phase before and after chloramphenicol-induction were prepared, and later sequenced to identify specific genes related to chloramphenicol-repercussion and drug-resistance. A total of 481 differentially expressed genes were revealed in chloramphenicol-resistant Cm5_36h and 1920 differentially expressed genes in chloramphenicol-dormant Cm_8h. Moreover, the gene expression profile in the chloramphenicol-dormant strain Cm_8h was quite different from that of Cm5_36 which had completely adapted to Cm, and 1513 differentially expression genes were identified between these two phenotypes. Besides upregulated acetyltransferases, several transporter encoding genes, including ABC transporters, major facilitator superfamily transporters (MFS), resistance-nodulation-cell division (RND) super family transporters and multidrug and toxic compound extrusion family transporters (MATE) were found to be involved in Cm resistance. After the knockout of the most highly upregulated MXAN_2566 MFS family gene, mutant strain DK-2566 was proved to be sensitive to Cm by measuring the growth curve in the Cm-added condition. A plasmid with a Cm resistance marker was constructed and integrated into chromosomes via homologous recombination and Cm screening. The integration efficiency was about 20% at different concentrations of Cm. CONCLUSIONS: This study provides a new antibiotic-based selection system, and will help to understand antibiotic resistance mechanisms in M. xanthus DK1622.

Ambient PM1 air pollution, blood pressure, and hypertension: Insights from the 33 Communities Chinese Health Study.

No evidence exists concerning the association between blood pressure and ambient particles with aerodynamic diameter ≤ 1.0 µm (PM1), a major component of PM2.5 (≤ 2.5 µm) particles, and potentially causing more hazardous health effects than PM2.5. We aimed to examine the associations of blood pressure in adults with both PM1 and PM2.5 in China. In 2009, we randomly selected 24,845 participants aged 18-74 years from 33 communities in China. Using a standardized mercuric-column sphygmomanometer, we measured blood pressure. Long-term exposure (2006-08) to PM1 and PM2.5 were estimated using a spatial statistical model. Generalized linear mixed models were used to evaluate the associations between air pollutants and blood pressure and hypertension prevalence, controlling for multiple covariates. A 10-µg/m3 increase in PM1 was significantly associated with an increase of 0.57 (95% CI 0.31-0.83) mmHg in systolic blood pressure (SBP), 0.19 (95% CI 0.03-0.35) mmHg increase in diastolic blood pressure (DBP), and a 5% (OR=1.05; 95% CI 1.01-1.10) increase in odds for hypertension. Similar associations were detected for PM2.5. Furthermore, PM1-2.5 showed no association with blood pressure or hypertension. In summary, both PM1 and PM2.5 exposures were associated with elevated blood pressure levels and hypertension prevalence in Chinese adults. In addition, most of the pro-hypertensive effects of PM2.5 may come from PM1. Further longitudinal designed studies are warranted to validate our findings.

Coenurosis of Yak, Bos grunniens, caused by Taenia multiceps: A Case Report with Molecular Identification in Qinghai Tibetan Plateau Area, China.

Coenurosis is an important zoonotic helminthic disease caused by the larval stage of the tapeworm Taenia multiceps. This parasite typically infects the brain of the intermediate hosts, including sheep, goat, cattle and even humans. We report a case of T. multiceps infection in a yak confirmed by clinical symptoms, morphological characteristics, and molecular and phylogenetic analyses. The coenurus was thin-walled, whitish, and spherical in shape with a diameter of 10 cm. The parasite species was identified as T. multiceps by PCR amplification and sequencing of the 18S rRNA, cox1 and nad1 genes. Three gene sequences all showed high homology (all above 97%) with the reference sequences from different hosts. Moreover, phylogenetic reconstructions with the 3 published Taenia gene sequences confirmed that the Qinghai yak isolate was closely related to T. multiceps. Although there are advanced diagnosis and treatment methods for coenurosis, early infection is difficult to diagnose. Importantly, the findings of yak infection case should not be ignored due to its zoonotic potential.

CRISPR/dCas9-mediated transcriptional improvement of the biosynthetic gene cluster for the epothilone production in Myxococcus xanthus.

BACKGROUND: The CRISPR/dCas9 system is a powerful tool to activate the transcription of target genes in eukaryotic or prokaryotic cells, but lacks assays in complex conditions, such as the biosynthesis of secondary metabolites. RESULTS: In this study, to improve the transcription of the heterologously expressed biosynthetic genes for the production of epothilones, we established the CRISPR/dCas9-mediated activation technique in Myxococcus xanthus and analyzed some key factors involving in the CRISPR/dCas9 activation. We firstly optimized the cas9 codon to fit the M. xanthus cells, mutated the gene to inactivate the nuclease activity, and constructed the dCas9-activator system in an epothilone producer. We compared the improvement efficiency of different sgRNAs on the production of epothilones and the expression of the biosynthetic genes. We also compared the improvement effects of different activator proteins, the ω and α subunits of RNA polymerase, and the sigma factors σ54 and CarQ. By using a copper-inducible promoter, we determined that higher expressions of dCas9-activator improved the activation effects. CONCLUSIONS: Our results showed that the CRISPR/dCas-mediated transcription activation is a simple and broadly applicable technique to improve the transcriptional efficiency for the production of secondary metabolites in microorganisms. This is the first time to construct the CRISPR/dCas9 activation system in myxobacteria and the first time to assay the CRISPR/dCas9 activations for the biosynthesis of microbial secondary metabolites.

O-Phenylenediamine: a privileged pharmacophore of ferrostatins for radical-trapping reactivity in blocking ferroptosis.

Ferroptosis is a non-apoptotic, iron dependent form of regulated cell death that is characterized by the accumulation of lipid hydroperoxides. It has drawn considerable attention owing to its putative involvement in diverse neurodegenerative diseases. Ferrostatins are the first identified inhibitors of ferroptosis and they inhibit ferroptosis by efficiently scavenging free radicals in lipid bilayers. However, their further medicinal application has been limited due to the deficient knowledge of the lipid peroxyl radical-trapping mechanism. In this study, experimental and theoretical methods were performed to illustrate the possible lipid hydroperoxide inhibition mechanism of ferrostatins. The results show that an ortho-amine (-NH) moiety from ferrostatins can simultaneously interact with lipid radicals, and then form a planar seven-membered ring in the transition state, and finally present greater reactivity. NBO analysis shows that the formed planar seven-membered ring forces ortho-amines into better alignment with the aromatic π-system. It significantly increases the magnitudes of amine conjugation and improves spin delocalization in the transition state. Additionally, a classical H-bond type interaction was discovered between a radical and an o-NH group as another transition state stabilizing effect. This type of radical-trapping mechanism is novel and has not been found in diphenylamine or traditional polyphenol antioxidants. It can be said that o-phenylenediamine is a privileged pharmacophore for the design and development of ferroptosis inhibitors.