Prokaryotic viruses impact functional microorganisms in nutrient removal and carbon cycle in wastewater treatment plants.

As one of the largest biotechnological applications, activated sludge (AS) systems in wastewater treatment plants (WWTPs) harbor enormous viruses, with 10-1,000-fold higher concentrations than in natural environments. However, the compositional variation and host-connections of AS viruses remain poorly explored. Here, we report a catalogue of ~50,000 prokaryotic viruses from six WWTPs, increasing the number of described viral species of AS by 23-fold, and showing the very high viral diversity which is largely unknown (98.4-99.6% of total viral contigs). Most viral genera are represented in more than one AS system with 53 identified across all. Viral infection widely spans 8 archaeal and 58 bacterial phyla, linking viruses with aerobic/anaerobic heterotrophs, and other functional microorganisms controlling nitrogen/phosphorous removal. Notably, Mycobacterium, notorious for causing AS foaming, is associated with 402 viral genera. Our findings expand the current AS virus catalogue and provide reference for the phage treatment to control undesired microorganisms in WWTPs.

Curcumin Ameliorates Copper-Induced Neurotoxicity Through Inhibiting Oxidative Stress and Mitochondrial Apoptosis in SH-SY5Y Cells.

Impaired homeostasis of copper has been linked to different pathophysiological mechanisms in neurodegenerative diseases and oxidative injury has been proposed as the main mechanism. This study aims to use curcumin, a widely used antioxidative and anti-apoptotic agent, to exert the neuroprotective effect against copper in vitro and illuminate the underlying mechanism. The effect of curcumin was examined by using a cell counting kit-8 assay, flow cytometry, immunofluorescence, spectrophotometer, and western blot. Results revealed that after pretreatment with curcumin for 3 h, copper-induced toxicity and apoptosis show a significant decline. Further experiments showed that curcumin not only decreased the production of ROS and MDA but also increased the activities of the ROS scavenging enzymes SOD and CAT. Moreover, curcumin treatment alleviated the decrease in mitochondrial membrane potential and the nuclear translocation of cytochrome c induced by copper. The protein levels of pro-caspase 3, pro-caspase 9, and PARP1 were up-regulated and the Bax/Bcl-2 ratio was down-regulated in the presence of curcumin. Taken together, our study demonstrates that curcumin has neuroprotective properties against copper in SH-SY5Y cells and the potential mechanisms might be related to oxidative stress and mitochondrial apoptosis.

Effects of organic chromium sources on growth performance, lipid metabolism, antioxidant status, breast amino acid and fatty acid profiles in broilers.

BACKGROUND: Trivalent chromium (Cr) is involved in carbohydrate, lipid, protein and nucleic acid metabolism in animals. This study evaluated the effects of different organic Cr forms with Cr methionine (CrMet), Cr picolinate (CrPic), Cr nicotinate (CrNic), and Cr yeast (Cr-yeast) at the level of 400 µg kg-1 Cr, on growth performance, lipid metabolism, antioxidant status, breast amino acid and fatty acid profiles of broilers. In total, 540 one-day-old Arbor Acres male broilers were randomly assigned to five treatments with six replicates (18 broilers per replicate) until day 42. RESULTS: The results showed growth performance was not affected by Cr sources. The Cr-yeast group had lower serum cortisol levels than the CrNic group (P < 0.05). Besides, Cr-yeast increased methionine and cysteine content in breast compared with the control group. Liver malondialdehyde content was lower in the CrMet group than the CrPic group on day 42 (P < 0.05). The n-3 polyunsaturated fatty acid (PUFA) values were increased, but the n-6/n-3 PUFA ratio was decreased in both CrMet and CrNic groups (P < 0.05). There were no significant effects on broilers' serum antioxidant status and breast total essential amino acid content among all treatments. CONCLUSIONS: Diets supplemented with organic Cr could regulate lipid metabolism, and improve amino acid and fatty acid profiles in broiler breast. Moreover, Cr-yeast was the most effective source in improving methionine and cysteine content, whereas CrMet was more effective than CrNic in increasing n-3 PUFA value and decreasing n-6/n-3 PUFA ratio in breast meat and effectively strengthened liver antioxidant ability than CrPic. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Dietary Fiber Increases Butyrate-Producing Bacteria and Improves the Growth Performance of Weaned Piglets.

The study investigated the impact of dietary fibers on the performance, fecal short-chain fatty acids, nutrient digestibility, and bacterial community in weaned piglets with the control group (CON) and dietary supplementation of 5% corn bran (CB), 5% wheat bran (WB), or 5% soybean hulls (SB). The piglets in CB and WB groups showed greater weight gain and feed efficiency ( p < 0.05) in comparison to piglets in CON and SB groups. Fecal samples from piglets in CB, SB, and WB groups contained greater ( p < 0.05) butyrate levels than fecal samples from piglets in the CON group. The fecal samples from piglets in CB or WB groups contained greater ( p < 0.05) abundances of Actinobacteria and Firmicutes or Fibrobacteres than the fecal sample from piglets in the CON group, which could promote fiber degradation and the production of butyrate. In summary, dietary CB or WB may enhance the growth performance of weaned piglets via altering gut microbiota and improving butyrate production, which shed light on the mechanism of dietary fiber in improving gut health.

Pathogenic Effects of Biofilm on Pseudomonas Aeruginosa Pulmonary Infection and Its Relationship to Cytokines.

BACKGROUND An animal (Sprague-Dawley rat) model of Pseudomonas aeruginosa biofilm associated with chronic pulmonary infection in vivo was established and the effects of the biofilm on P. aeruginosa and its relationship to cytokines were investigated. MATERIAL AND METHODS Biofilm of P. aeruginosa in alginate beads and planktonic PA0725 were purified by anion-exchange chromatograph. Sprague-Dawley (SD) rats were immunized with the biofilm and then inhaled the same strain of P. aeruginosa. Anti-biofilm antibody titer was detected using the enzyme linked immunosorbent assay (ELISA) method. The cell count and differential count in the bronchoalveolar lavage fluid (BALF) were measured. The levels of cytokines (IL-17, IL-1ß, MIP-2, and G-CSF) and tumor necrosis factor (TNF)-α in sera were also measured using an ELISA kit. RESULTS The sera anti-biofilm IgG antibody titer of immunized SD rats was increased significantly on the 5th and 8th days after inhalation. The IL-17 concentration was significantly higher on the 8th day after inhalation. The results indicated that when biofilm-pre-immunized rats were challenged with inhalation of PA0725 of P. aeruginosa, the biofilm acted as an antigen substance and mediated the antibody reaction of the antigen, which might cause serious airway inflammatory response and lung tissue injury. This effect may be related to IL-17. CONCLUSIONS P. aeruginosa biofilm protected the bacterium from antibiotics and might induce host immune damage in lung tissue and facilitate bacterium evading the host barrier.

Baicalein attenuates the quorum sensing-controlled virulence factors of Pseudomonas aeruginosa and relieves the inflammatory response in P. aeruginosa-infected macrophages by downregulating the MAPK and NFκB signal-transduction pathways.

Burgeoning antibiotic resistance and unfavorable outcomes of inflammatory injury after Pseudomonas aeruginosa infection have necessitated the development of novel agents that not only target quorum sensing (QS) but also combat inflammatory injury with the least risk of resistance. This study aimed to assess the anti-QS and anti-inflammatory activities of baicalein, a traditional herbal medicine that is widely used in the People's Republic of China, against P. aeruginosa infection. We found that subminimum inhibitory concentrations of baicalein efficiently interfered with the QS-signaling pathway of P. aeruginosa via downregulation of the transcription of QS-regulated genes and the translation of QS-signaling molecules. This interference resulted in the global attenuation of QS-controlled virulence factors, such as motility and biofilm formation, and the secretion into the culture supernatant of extracellular virulence factors, including pyocyanin, LasA protease, LasB elastase, and rhamnolipids. Moreover, we examined the anti-inflammatory activity of baicalein and its mode of action via a P. aeruginosa-infected macrophage model to address its therapeutic effect. Baicalein reduced the P. aeruginosa-induced secretion of the inflammatory cytokines IL-1ß, IL-6, IL-8, and TNFα. In addition, baicalein suppressed P. aeruginosa-induced activation of the MAPK and NFκB signal-transduction pathways in cocultured macrophages; this may be the mechanism by which baicalein inhibits the production of proinflammatory cytokines. Therefore, our study demonstrates that baicalein represents a potential treatment for P. aeruginosa infection because it clearly exhibits both antibacterial and anti-inflammatory activities.