Use of 16S rRNA gene sequences to identify cyanobacteria that can grow in far-red light.

Although most cyanobacteria use visible light (VL; λ = 400-700 nm) for photosynthesis, some have evolved strategies to use far-red light (FRL; λ = 700-800 nm). These cyanobacteria are defined as far-red light-utilizing cyanobacteria (FRLCyano), including two groups: (1) chlorophyll d-producing Acaryochloris spp. and (2) polyphyletic cyanobacteria that produce chlorophylls d and f in response to FRL. Numerous ecological studies examine pigments, such as chlorophylls d and f, to investigate the presence of FRLCyano in the environment. This method is not ideal because it can only detect FRLCyano that have made chlorophylls d or f. Here we develop a new method, far-red cyanobacteria identification (FRCI), to identify FRLCyano based on 16S rRNA gene sequences. From public databases and published articles, 62 16S rRNA gene sequences of FRLCyano were extracted. Comparing with related lineages, we determined that 97% sequence identity is the optimal cut-off for distinguishing FRLCyano from other cyanobacteria. To test the method experimentally, we collected samples from 17 sites in Taipei, Taiwan, and conducted VL and FRL enrichments. Our results demonstrate that FRCI can detect FRLCyano during FRL enrichments more sensitively than pigment analysis. FRCI can also resolve the composition of FRLCyano at the genus level, which pigment analysis cannot do. In addition, we applied FRCI to published datasets and discovered putative FRLCyano in diverse environments, including soils, hot springs and deserts. Overall, our results indicate that FRCI is a sensitive and high-resolution method using 16S rRNA gene sequences to identify FRLCyano.

[Effect of two-level community-based health education pattern on schistosomiasis control].

OBJECTIVE: To implement a two-level community-based health education pattern of schistosomiasis in residents of endemic areas in marshland and lake regions, so as to explore the suitable pattern of health education under hypo-endemic situation. METHODS: Two schistosomiasis endemic villages in Jiangling County, Hubei Province were collected as study areas, and among which, one village was treated as an intervention group, where the two-level community-based health education pattern as well as regular control measures was implemented; the other village was a control group, where only regular control measures were implemented. The awareness rates on schistosomiasis control, the rates of correct behavior and the compliance rates of examination, treatment and chemotherapy of the two groups before and after the intervention were compared. RESULTS: According to the results of the baseline survey in 2014, the awareness rates of schistosomiasis control of the intervention and control groups were 84.00% and 77.45%, respectively, the correct rates of behavior of the two groups were 72.00% and 63.73%, respectively, and the compliance rates of the treatment were 80.36% and 82.28%, respectively, there were no statistically significant differences between all the above rates of the two groups (all P > 0.05). After the intervention of the two-level community-based health education, the correct rates of behavior, and the compliance rates of examination and chemotherapy of the two groups were 92.31% and 80.37%, 95.11% and 82.55%, 84.13% and 63.64%, respectively, and the differences between all the rates above of the two groups were statistically significant (all P < 0.05). When compared to those before intervention, the growing rates of the compliance rates of examination, treatment and chemotherapy of the intervention group were 20.97%, 15.33% and 23.29%, respectively, while those of control group were 14.27%, 4.17%, -3.77%, respectively, the growing rates of the intervention groups were higher than those of the control groups. CONCLUSIONS: Through the two-level community-based pattern of health education, the compliance rates of examination and treatment of the residents have improved, and therefore, the pattern is suitable for popularization and application in marshland and lake regions.