Influence of Polysaccharides From Polygonatum kingianum on Short-Chain Fatty Acid Production and Quorum Sensing in Lactobacillus faecis.

Polysaccharide is one of the main active ingredients of Polygonatum kingianum, which has been proven to regulate the balance of gut microbiota. For the first time, this study focused on the regulation of polysaccharides from Polygonatum kingianum (PS) on Lactobacillus faecis, a specific probiotic in the intestinal tract. PS effectively promoted the biomass, biofilm and acetic acid production in L. faecis 2-84, and enhanced quorum sensing (QS) signaling. The characteristics of gene sequence were analyzed using genomics approaches, and L. faecis 2-84 was found to encode 18 genes that are closely related to QS and 10 genes related to short-chain fatty acids (SCFAs). Additionally, transcriptome and proteome analysis demonstrated that PS could promote the QS system of L. faecis by enhancing the transcription of oppA gene and expression of oppD protein. PS also regulated the production and metabolism of SCFAs of L. faecis by upregulating the expression of ldh and metE gene and adh2 protein, and downregulating the expression of mvK gene. In conclusion, it was speculated that PS could affect intestinal SCFAs production by affecting the QS system and SCFAs production in L. faecis. The present study implied that PS might have a role in promoting the growth of intestinal probiotics, where the QS system and SCFAs might be two of the important mechanisms for the probiotic activity of PS.

Stance markers in English medical research articles and newspaper opinion columns: A comparative corpus-based study.

Stance markers are critical linguistic devices for writers to convey their personal attitudes, judgments or assessments about the proposition of certain messages. Following Hyland's framework of stance, this study investigated the distribution of stance markers in two different genres: medical research articles (medical RA) and newspaper opinion columns (newspaper OC). The corpus constructed for the investigation includes 52 medical research articles and 175 newspaper opinion articles, which were both written in English and published from January to April in 2020 with the topic focusing on COVID-19. The findings of this study demonstrated that the occurrences of stance markers in newspaper OC were far more frequent than those in medical RA, indicating the different conventions of these two genres. Despite the significant difference in the occurrences of stance markers between the two sub-corpora, similarities of the most frequent stance markers in two genres were also highlighted. The study indicated that the topic content seems to play an important role in shaping the way of how writers construct their stance. The lack of information or evidence on the topic of COVID-19 could restrain writers from making high degree of commitment to their claims, which make them adopt a more tentative stance to qualify their statements.

Effects of Natural Products on Bacterial Communication and Network-Quorum Sensing.

Quorum sensing (QS) has emerged as a research hotspot in microbiology and medicine. QS is a regulatory cell communication system used by bacterial flora to signal to the external environment. QS influences bacterial growth, proliferation, biofilm formation, virulence factor production, antibiotic synthesis, and environmental adaptation. Through the QS system, natural products can regulate the growth of harmful bacteria and enhance the growth of beneficial bacteria, thereby improving human health. Herein, we review advances in the discovery of natural products that regulate bacterial QS systems.

[Effect of traditional Chinese medicine in improving human health by regulating bacterial quorum sensing system].

Quorum sensing(QS) is one of the research hotspots in the fields of microbiology and medicine in recent years. Quorum sensing is a cell communication regulatory system, which is used by bacterial flora to pass on information of population density by sensing specific signaling molecules to the environment. The QS system of bacteria can impact biological functions, such as bacterial growth, proliferation, biofilm formation, virulence factor production, antibiotic synthesis, and ultimately adapt the bacteria to environmental changes. At present, more and more active ingredients can regulate quorum sensing have been found in traditional Chinese medicines(TCM). TCM and their active ingredients can promote the growth of beneficial bacteria, inhibit the proliferation of pathogenic bacteria and finally achieve the purpose of treating diseases. It embodies multi-pathway and multi-target characteristics of traditional Chinese medicine. This article first introduces molecular types and regulation mechanisms of quorum sensing signals between bacteria. On this basis, the human health-related bacterial quorum sensing is summarized, and the regulatory effect of TCM on bacterial quorum sensing system is discussed. Finally, it is noted that the material basis and mechanisms of TCM in improving human health through bacterial quorum sensing system are still unclear. Future research hotspots will focus on quorum sensing active substances, quorum sensing key nodes and relevant targets. In a word, this article provides reference for the treatment of relevant diseases.