Expression of Heterologous OsDHAR Gene Improves Glutathione (GSH)-Dependent Antioxidant System and Maintenance of Cellular Redox Status in Synechococcus elongatus PCC 7942

Investigating the Roles for Essential Genes in the Regulation of the Circadian Clock in Synechococcus elongatus Using CRISPR Interference

Circadian rhythms are found widely throughout nature where cyanobacteria are the simplest organisms, in which the molecular details of the clock have been elucidated. Circadian rhythmicity in cyanobacteria is carried out via the KaiA, KaiB, and KaiC core oscillator proteins that keep ~24 h time. A series of input and output proteins-CikA, SasA, and RpaA-regulate the clock by sensing environmental changes and timing rhythmic activities, including global rhythms of gene expression. Our previous work identified a novel set of KaiC-interacting proteins, some of which are encoded by genes that are essential for viability. To understand the relationship of these essential genes to the clock, we applied CRISPR interference (CRISPRi) which utilizes a deactivated Cas9 protein and single-guide RNA (sgRNA) to reduce the expression of target genes but not fully abolish their expression to allow for survival. Eight candidate genes were targeted, and strains were analyzed by quantitative real-time PCR (qRT-PCR) for reduction of gene expression, and rhythms of gene expression were monitored to analyze circadian phenotypes. Strains with reduced expression of SynPCC7942_0001, dnaN, which encodes for the β-clamp of the replicative DNA polymerase, or SynPCC7942_1081, which likely encodes for a KtrA homolog involved in K+ transport, displayed longer circadian rhythms of gene expression than the wild type. As neither of these proteins have been previously implicated in the circadian clock, these data suggest that diverse cellular processes, DNA replication and K+ transport, can influence the circadian clock and represent new avenues to understand clock function.

Galacto-Oligosaccharide Alleviates Alcohol-Induced Liver Injury by Inhibiting Oxidative Stress and Inflammation

Alcoholic liver disease (ALD) is a primary cause of mortality and morbidity worldwide. Oxidative stress and inflammation are important pathogenic factors contributing to ALD. We investigated the protective mechanism of galacto-oligosaccharide (GOS) against ALD through their antioxidant and anti-inflammatory activities by performing in vivo and in vitro experiments. Western blot and RT‒PCR results indicated that the expression of cytochrome P450 protein 2E1 (CYP2E1) in liver tissues and L02 cells was reduced in the GOS-treated mice compared with the model group. In addition, GOS prominently reduced the expression of Kelch-like ECH-associated protein 1 (Keap1), increased the expression of the nuclear factor erythroid-2-related factor 2 (Nrf2) and haem oxygenase-1 (HO-1) proteins, and enhanced the antioxidant capacity. In addition, GOS decreased inflammation by reducing inflammatory factor levels and inhibiting the mitogen-activated protein kinase (MAPK)/nuclear factor kappa B (NF-κB) pathway. Based on these results, GOS may be a prospective functional food for the prevention and treatment of ALD.

The influence of PM2.5 exposure on kidney diseases

The harm of air pollution to public health has become a research hotspot, especially atmospheric fine-particulate matter (PM_2.5). In recent years, epidemiological investigations have confirmed that PM_2.5 is closely related to chronic kidney disease and membranous nephropathy Basic research has demonstrated that PM_2.5 has an impact on the normal function of the kidneys through accumulation in the kidney, endothelial dysfunction, abnormal renin-angiotensin system, and immune complex deposition. Moreover, the mechanism of PM_2.5 damage to the kidney involves inflammation, oxidative stress, apoptosis, DNA damage, and autophagy. In this review, we summarized the latest developments in the effects of PM_2.5 on kidney disease in human and animal studies, so as to provide new ideas for the prevention and treatment of kidney disease.

Enhancement of Biomass Production in Colony-Forming Green Algae, Botryosphaerella sudetica, Under Mixotrophic Cultivation

In this study, we characterized the potential of colony-forming green algae, Botryosphaerella sudetica KNUA107, isolated from Ulleung Island, South Korea, as a bioresource and analyzed the effects of mixotrophic cultivation on its bioresource production efficiency. Internal transcribed spacer (ITS) (ITS1, 5.8S, and ITS2), ribulose bisphosphate carboxylase large subunit (rbcL), and elongation factor Tu (tufa) regions were used for molecular identification and phylogenetic analysis. B. sudetica KNUA107 had a strong relationship with the green algae of Botryococcus and Botryosphaerella genera, which are colony-forming species, and was also associated with members of the Neochloris genus. To improve biomass productivity, we tested mixotrophic cultivation conditions using several organic carbon sources. Glucose supplementation stimulated B. sudetica KNUA107 growth and reduced the time needed to reach the stationary phase. In addition, the colony size was 1.5–2.0 times larger with glucose than in photoautotrophic cultures, and settleability improved in proportion to colony size. The total lipid content and biomass productivity were also higher in cultures supplemented with glucose. Among the lipid components, saturated fatty acids and monounsaturated fatty acids had the highest proportion. Our study suggests that B. sudetica KNUA107, which has enhanced efficiency in biomass production and lipid components under mixotrophic cultivation, has high potential as a bioresource.