Gut microbiota: A new insight into lung diseases.

The human gut microbiota is a complex ecosystem involved in the metabolism, immunity, and health of the host. The microbiome plays a key role in the development of the host's innate and adaptive immune system, while the immune system orchestrates the maintenance of host-microbe symbiosis. Lung diseases are usually accompanied by dysbiosis of the intestinal flora and an immune-inflammatory response. The intestinal flora and its metabolites are directly or indirectly involved in the immune regulation of the host in lung disease. However, the exact mechanism of action of the gut-lung axis crosstalk remains unclear. This review is aimed to summarize the latest advances in gut microbiota and their metabolites in typical lung diseases, such as pulmonary hypertension, COPD, and lung cancer. Especially COVID-19, a problem troubling the world, is also discussed in it. Moreover, it is concentrated on the action mechanisms between the identified gut microbiota or their metabolites and the specific lung diseases, and on the link among the gut microbiota, its metabolites, and immune regulation, which could be used as a breakthrough to find new mechanisms and targets for some diseases without specific therapeutic drugs in clinic. It is also discussed a new therapeutic tool "drug-bacterial interaction" and the potential of therapeutic applications in clinic. This review would provide a clear direction for future research on gut microbiota and lung diseases, and propose a new therapeutic strategy targeting "drug-bacterial interaction" in clinic.

Homologous comparisons of photosynthetic system I genes among cyanobacteria and chloroplasts.

It has now believed that chloroplasts arose from cyanobacteria, however, during endosymbiosis, the photosynthetic genes in chloroplasts have been reduced. How these changes occurred during plant evolution was the focus of the present study. Beginning with photosystem I (PSI) genes, a homologous comparison of amino acid sequences of 18 subunits of PSI from 10 species of cyanobacteria, chloroplasts in 12 species of eucaryotic algae, and 28 species of plants (including bryophytes, pteridophytes, gymnospermae, dicotyledon and monocotyledon) was undertaken. The data showed that 18 genes of PSI can be divided into two groups: Part I including seven genes (psaA, psaB, psaC, psaI, psaJ, ycf3 and ycf4) shared both by cyanobacteria and plant chloroplasts; Part II containing another 11 genes (psaD, psaE, psaF, psaK, psaL, psaM, btpA, ycf37, psaG, psaH and psaN) appeared to have diversified in different plant groups. Among Part I genes, psaC, psaA and psaB had higher homology in all species of cyanobacteria and chloroplasts. Among Part II genes, only psaG, psaH and psaN emerged in seed plants.