A linear and circular dual-conformation noncoding RNA involved in oxidative stress tolerance in Bacillus altitudinis.

Circular RNAs have been extensively studied in eukaryotes, but their presence and/or biological functionality in bacteria are unclear. Here, we show that a regulatory noncoding RNA (DucS) exists in both linear and circular conformation in Bacillus altitudinis. The linear forms promote B. altitudinis tolerance to H2O2 stress, partly through increased translation of a stress-responsive gene, htrA. The 3' end sequences of the linear forms are crucial for RNA circularization, and formation of circular forms can decrease the levels of the regulatory linear cognates. Bioinformatic analysis of available RNA-seq datasets from 30 bacterial species revealed multiple circular RNA candidates, distinct from DucS, for all the examined species. Experiments testing for the presence of selected circular RNA candidates in four species successfully validated 7 out of 9 candidates from B. altitudinis and 4 out of 5 candidates from Bacillus paralicheniformis; However, none of the candidates tested for Bacillus subtilis and Escherichia coli were detected. Our work identifies a dual-conformation regulatory RNA in B. altitutidinis, and indicates that circular RNAs exist in diverse bacteria. However, circularization of specific RNAs does not seem to be conserved across species, and the circularization mechanisms and biological functionality of the circular forms remain unclear.

Relationship between polymorphism of interleukin-8 and silicosis susceptibility / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the relationship between the polymorphisms of interleukin-8 (IL-8) and the silicosis susceptibility.</p><p><b>METHODS</b>The case group consisted of 101 male patients with stage I silicosis diagnosed by the Pneumoconiosis Diagnosis Expert Panel according to the Chinese National Diagnosis Criteria of Pneumoconiosis (GBZ 70-2009). The control group consisted of 121 workers without silicosis exposed to same dusts. The cases and the controls had the same dust exposure history. The peripheral venous blood was drawn from each subject. DNA was extracted from leucocytes by the salting method. The polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) techniques and PCR were used to examine polymorphism of IL-8 (Met31Arg, 781C/T, -251A/T and RA+860).</p><p><b>RESULTS</b>There were no the differences of age, cumulative exposure time and smoking between the cases and the controls (P > 0.05). The frequencies of IL-8 (Met31Arg) GT genotypes in cases and controls were 12.87% and 2.48%, respectively, there was significant difference (P < 0.05). The frequencies of allele G in cases and controls were 6.44% and 2.07%, respectively, there was significant difference (P < 0.05). The frequencies of IL-8 (-251A/T) AA genotypes in cases and controls were 9.90% and 25.64%, respectively, there was significant difference (P < 0.05). The frequencies of IL-8 (781C/T) CC, CT, TT genotypes in cases and controls were 38.61%, 40.59%, 20.79% and 46.28%, 40.50%, 13.22%, respectively, there was no significant difference (P > 0.05). The frequencies of IL-8 (RA+860) GG, GC and CC genotypes in cases and controls were 75.25%, 21.78%, 2.97%, 80.17%, 14.88%, 4.96%, respectively, there was no significant difference (P > 0.05).</p><p><b>CONCLUSIONS</b>IL-8 (Met31Arg and -251A/T) genetic polymorphisms might play a role in the development of silicosis. The risk of pneumoconiosis in workers carrying (Met31Arg) genotype GT is likely to increase. The risk of pneumoconiosis in workers carrying IL-8 (-251A/T) AA genotype is likely to decrease. The relationship between IL-8 781C/T and RA+860 genes polymorphisms and silicosis is not found.</p>