UV-A radiation increases biomass yield by enhancing energy flow and carbon assimilation in the edible cyanobacterium Nostoc sphaeroides.

Ultraviolet (UV) A radiation (315-400 nm) is the predominant component of solar UV radiation that reaches the Earth's surface. However, the underlying mechanisms of the positive effects of UV-A on photosynthetic organisms have not yet been elucidated. In this study, we investigated the effects of UV-A radiation on the growth, photosynthetic ability, and metabolome of the edible cyanobacterium Nostoc sphaeroides. Exposures to 5-15 W m-2 (15-46 µmol photons m-2 s-1) UV-A and 4.35 W m-2 (20 µmol photons m-2 s-1) visible light for 16 days significantly increased the growth rate and biomass production of N. sphaeroides cells by 18%-30% and 15%-56%, respectively, compared to the non-UV-A-acclimated cells. Additionally, the UV-A-acclimated cells exhibited a 1.8-fold increase in the cellular nicotinamide adenine dinucleotide phosphate (NADP) pool with an increase in photosynthetic capacity (58%), photosynthetic efficiency (24%), QA re-oxidation, photosystem I abundance, and cyclic electron flow (87%), which further led to an increase in light-induced NADPH generation (31%) and ATP content (83%). Moreover, the UV-A-acclimated cells showed a 2.3-fold increase in ribulose-1,5-bisphosphate carboxylase/oxygenase activity, indicating an increase in their carbon-fixing capacity. Gas chromatography-mass spectrometry-based metabolomics further revealed that UV-A radiation upregulated the energy-storing carbon metabolism, as evidenced by the enhanced accumulation of sugars, fatty acids, and citrate in the UV-A-acclimated cells. Therefore, our results demonstrate that UV-A radiation enhances energy flow and carbon assimilation in the cyanobacterium N. sphaeroides.IMPORTANCEUltraviolet (UV) radiation exerts harmful effects on photo-autotrophs; however, several studies demonstrated the positive effects of UV radiation, especially UV-A radiation (315-400 nm), on primary productivity. Therefore, understanding the underlying mechanisms associated with the promotive effects of UV-A radiation on primary productivity can facilitate the application of UV-A for CO2 sequestration and lead to the advancement of photobiological sciences. In this study, we used the cyanobacterium Nostoc sphaeroides, which has an over 1,700-year history of human use as food and medicine, to explore its photosynthetic acclimation response to UV-A radiation. As per our knowledge, this is the first study to demonstrate that UV-A radiation increases the biomass yield of N. sphaeroides by enhancing energy flow and carbon assimilation. Our findings provide novel insights into UV-A-mediated photosynthetic acclimation and provide a scientific basis for the application of UV-A radiation for optimizing light absorption capacity and enhancing CO2 sequestration in the frame of a future CO2 neutral, circular, and sustainable bioeconomy.

The Gastric Microbiome Is Perturbed in Advanced Gastric Adenocarcinoma Identified Through Shotgun Metagenomics.

Objective: Dysbiosis of gastric microbiota such as Helicobacter pylori plays a significant role in pathogenesis and progression of gastric cancer. Our aim was to evaluate the composition and functional effects of gastric microbiota in superficial gastritis (SG) and advanced gastric adenocarcinoma (GC). Methods: We carried out shotgun metagenomic sequencing on gastric wash samples from 6 patients with GC and 5 patients with SG. The taxonomic composition was profiled using MetaPhlAn2 and functional gene pathway was profiled using HUMAnN2. Differences in microbial composition and pathways between the two patient groups were assessed via LEfSe. Results: The gastric microbiota in GC patients was characterized by reduced species richness, enrichment of 13 bacterial taxa and depletion of 31 taxa (q < 0.05). The most representative taxa which were abundant in GC corresponded to the commensals or opportunistic pathogens that usually colonize the oral cavity, including genera Neisseria, Alloprevotella, and Aggregatibacter, species Streptococcus_mitis_oralis_pneumoniae and strain Porphyromonas_endodontalis.t_GCF_000174815. Each of the three GC-associated genera could separate GC from SG completely. In particular, Sphingobium yanoikuyae, a bacterium capable of degrading carcinogenic compounds, was depleted in GC. Functionally, pathways associated with the biosynthesis of lipopolysaccharide (LPS) and L-arginine were enriched in GC, whereas pathways involved in the fermentation of short chain fatty acids (SCFAs) and branched amino acid metabolism were more abundant in SG. Conclusions: Our results present new alterations in the gastric microbiome in patients with GC from a whole-genome perspective, suggesting that microbiome composition and function can be used for prognosis and diagnosis of GC.

[Effects of Neurotrophin Receptor-interacting MAGE Homolog on Apoptosis of Intestinal Epithelial Cells].

OBJECTIVE: To explore whether neurotrophin receptor-interacting MAGE homolog (NRAGE) is involved in the intestinal ischemia-reperfusion (I/R) and its effect on the apoptosis of intestinal epithelial cells and the expression of occludin protein. METHODS: The level of NRAGE protein after the rat small intestine I/R was detected by immunohistochemical (IHC) In vivo. The level of NRAGE protein and mRNA in IEC-6 cells after hypoxia and reoxygenation were tested by Western blot and RT-PCR respectively in vitro. The IEC-6 cells were divided into four groups, including NRAGE overexpression by lentivirus infection (Lv-NRAGE group), interference (sh-NRAGE group), lentivirus control (Lv-control group), and normal control group without lentivirus infection (NC group). The apoptosis of IEC-6 cells after infection was analyzed by flow cytometry. The level of the tight junction protein occludin was detected by Western blot. RESULTS: The expression of NRAGE were highly increased in intestinal mucosa epithelial cells after I/R (P<0.01). The proteins and mRNA levels of NRAGE were increased after 6 h of hypoxia in IEC-6 cellsin vitro. Compared with the Lv-control group, the early apoptosis rate was raised (P<0.01) and the level of occludin was reduced (P<0.01) in Lv-NRAGE group; while the early apoptosis rate was reduced (P<0.01) and the level of occludin was raised in sh-NRAGE group(P<0.001). CONCLUSION: NRAGE may be involved in intestinal I/R and promote the apoptosis and decrease occludin expression of intestinal epithelial cells.

In vitro evaluation of antiviral activity of tea seed saponins against porcine reproductive and respiratory syndrome virus.

BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the major swine pathogens. This virus causes immune suppression and other secondary infections, leading to significant economic losses in the swine industry. Tea seed saponins (TS) are a natural extract from tea seeds with anti-cancer, anti-inflammatory and antiviral activity. In this study, we demonstrated that TS possessed anti-PRRSV activity. METHODS: MTT assay and trypan blue staining were used to evaluate the cytotoxicity and antiviral ability of TS in cell culture. Apoptosis was measured to assess the safety of TS on Marc-145 cells. Time-of-addition assay, entry inhibition assay and virucidal assay were used to assess the antiviral action of TS. The effect of TS on host cellular gene expression was analysed by real-time PCR. Absolute quantification RT-PCR and western blot were used to study the inhibitory effect of TS on PRRSV N gene and protein expression. RESULTS: Our results showed that 50% cytotoxic concentrations (CC50) and 50% effective concentration (EC50) of TS were 59.86 ±0.3841 µg/ml and 24.29 ±1.194 µg/ml, respectively. The maximum non-cytotoxic concentration of TS on Marc-145 cells was 30 µg/ml. TS inhibited PRRSV-induced cell apoptosis and effectively inhibited PRRSV replication by reducing the expression of host cellular gene PABP, and significantly inhibited virus N gene/protein expression. CONCLUSIONS: TS possessed anti-PRRSV activity in vitro and could serve as a potential antiviral drug for PRRSV prevention and control.

Cordyceps militaris polysaccharides can enhance the immunity and antioxidation activity in immunosuppressed mice.

To evaluate the immune activation and reactive oxygen species scavenging activity of Cordyceps militaris polysaccharides (CMP) in vivo, 90 male BALB/c mice were randomly divided into six groups. The mice in the three experimental groups were given cyclophosphamide at 80 mg/kg/d via intraperitoneal injection and 17.5, 35, or 70 mg/kg body weight CMP via gavage. The lymphocyte proliferation, phagocytic index, and biochemical parameters were measured. The results show that the administration of CMP was able to overcome the CY-induced immunosuppression, significantly increased the spleen and thymus indices, and enhanced the spleen lymphocyte activity and macrophage function. CMP can also improve the antioxidation activity in immunosuppressed mice, significantly increase the superoxidase dismutase, catalase, and glutathione peroxidase levels and the total antioxidant capacity, and decrease the malondialdehyde levels in vivo.