[Epidemiology of allergic rhinitis in children in grassland of Inner mongolia].

Objective: To investigate the self-reported prevalence, clinical characteristics, complications of allergic rhinitis (AR) and the sensitization of outdoor air pollen allergens in children in the Inner mongolia grassland region. Methods: A multistage, stratified and random clustered sampling with a face-to-face interview survey study in children from 0 to 17 years old was performed together with 10 common allergen skin prick tests (SPT) and measurements of the daily pollen count in 6 regions in the Inner mongolia grassland region from May to August of 2015. SAS 9.4 software was used for data analysis. Results: A total of 2 443 subjects completed the study. The self-reported prevalence of AR was 26.6%. The prevalence of boys was higher than that of girls (28.8% vs 24.3%, χ(2)=6.157, P<0.05). Subjects from urban areas showed higher prevalence than rural areas (34.7% vs 18.8%, χ(2)=79.107, P<0.05). There was significant regional difference in the prevalence of AR among the six areas investigated (χ(2)=221.416, P<0.05). The main clinical symptoms of AR were sneezing (88.2%) and nasal congestion (78.6%). Among combined diseases, asthma accounted for 16.5% (107/650), rhinoconjunctivitis accounted for 47.9% (311/650). The peak season of AR was April and July, with the top SPT positive allergens of Artemisia species and chenopodium in this area. Conclusions: The prevalence AR in children in the Inner mongolia grassland region is extremely high. Sneezing is the main clinical symptom. Rhinoconjunctivitis is the most common combined disease. High summer and autumn pollen exposure is the main cause of AR.

Prevalence of pollen-induced allergic rhinitis with high pollen exposure in grasslands of northern China.

BACKGROUND: The aim of this study was to investigate the prevalence of epidemiologic and physician-diagnosed pollen-induced AR (PiAR) in the grasslands of northern China and to study the impact of the intensity and time of pollen exposure on PiAR prevalence. METHODS: A multistage, clustered and proportionately stratified random sampling with a field interviewer-administered survey study was performed together with skin prick tests (SPT) and measurements of the daily pollen count. RESULTS: A total of 6043 subjects completed the study, with a proportion of 32.4% epidemiologic AR and 18.5% PiAR. The prevalence was higher in males than females (19.6% vs 17.4%, P = .024), but no difference between the two major residential and ethnic groups (Han and Mongolian) was observed. Subjects from urban areas showed higher prevalence of PiAR than rural areas (23.1% vs 14.0%, P < .001). Most PiAR patients were sensitized to two or more pollens (79.4%) with artemisia, chenopodium, and humulus scandens being the most common pollen types, which were similarly found as the top three sensitizing pollen allergens by SPT. There were significant regional differences in the prevalence of epidemiologic AR (from 18.6% to 52.9%) and PiAR (from 10.5% to 31.4%) among the six areas investigated. PiAR symptoms were positively associated with pollen counts, temperature, and precipitation (P < .05), but negatively with wind speed and pressure P < .05). CONCLUSION: Pollen-induced AR (PiAR) prevalence in the investigated region is extremely high due to high seasonal pollen exposure, which was influenced by local environmental and climate conditions.

Expression of Heterogenous Arsenic Resistance Genes in the Obligately Autotrophic Biomining Bacterium Thiobacillus ferrooxidans.

Two arsenic-resistant plasmids were constructed and introduced into Thiobacillus ferrooxidans strains by conjugation. The plasmids with the replicon of wide-host-range plasmid RSF1010 were stable in T. ferrooxidans. The arsenic resistance genes originating from the heterotroph were expressed in this obligately autotrophic bacterium, but the promoter derived from T. ferrooxidans showed no special function in its original host.

Plasmid and transposon transfer to Thiobacillus ferrooxidans.

The broad-host-range IncP plasmids RP4, R68.45, RP1::Tn501, and pUB307 were transferred to acidophilic, obligately chemolithotrophic Thiobacillus ferrooxidans from Escherichia coli by conjugation. A genetic marker of kanamycin resistance was expressed in T. ferrooxidans. Plasmid RP4 was transferred back to E. coli from T. ferrooxidans. The broad-host-range IncQ vector pJRD215 was mobilized to T. ferrooxidans with the aid of plasmid RP4 integrated in the chromosome of E. coli SM10. pJRD215 was stable, and all genetic markers (kanamycin/neomycin and streptomycin resistance) were expressed in T. ferrooxidans. By the use of suicide vector pSUP1011, transposon Tn5 was introduced into T. ferrooxidans. The influence of some factors on plasmid transfer from E. coli to T. ferrooxidans was investigated. Results showed that the physiological state of donor cells might be important to the mobilization of plasmids. The transfer of plasmids from E. coli to T. ferrooxidans occurred in the absence of energy sources for both donor and recipient.