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Ginseng peptide (GP) (100, 200, 400 mg/kg bw) lowered blood glucose levels, explored the relationship between GP and gut microbiota-based hypoglycemic effects. GP significantly reduced fasting blood glucose levels (25.38–13.37 mM), improved insulin resistance (IR) (9.78–5.02), considerably increased liver glycogen content (64.71–97.95 mg/g), glycolytic and gluconeogenesis enzyme activities in T2DM mice, significantly reduced free fatty acids (1.65–0.93 mM), triglycerides (1.55–0.66 mM), total cholesterol (14.75–5.43 mM), and low-density lipoprotein (4.12–2.36 mM) in the serum, significantly increased high-density lipoprotein levels (6.20–17.44 mM) to improve lipid metabolism disorders. According to colonic 16S rDNA sequencing results, GP-H regulated gut microbiota disorders and short chain fatty acid metabolism. Western blot analysis showed that GP could regulate glycogen synthesis, gluconeogenesis, and glucose transport by activating IRS-1/PI3K/Akt and AMPK signaling pathways and improve IR by inhibiting the mitochondrial apoptosis signaling pathway.

Aspartokinase (AK) is synergistically suppressed by Thr and Lys in the Corynebacterium metabolic pathway. Site-directed mutations can significantly improve AK inhibition. Our previous studies confirmed that sites 379 and 380 were important sites affecting enzyme activity, so we further screen the double mutants with excellent enzymatic properties from sites 379 and 380, and discuss the difference of enzyme activity between the double mutants and single mutants. Here, a double mutant, T379L/A380 M, with improved enzyme activity (2.74-fold) was obtained. Enzymatic property experiments showed that the optimum temperature of T379L/A380 M increased from 26 °C (recombinant Escherichia coli; WT-AK) to 45 °C and that the optimal pH decreased from 8.0 (WT-AK) to 7.5. Further, the half-life decreased from 4.5 to 3.32 h. These enzymatic properties were better than other mutant strains. Inhibition was diminished with low concentrations of Lys, and Lys + Thr presented an activating role. Subsequently, the reasons for the improved AK enzyme activity were illustrated with microscale thermophoresis (MST) experiments and molecular dynamic (MD) simulation by measuring ligand affinity and AK conformational changes. MST showed that the affinity between T379L/A380 M and Lys decreased, but the affinity between T379L/A380 M and Asp increased, promoting T379L/A380 M enzyme activity. MD experiments showed that T379L/A380 M enhanced the Asp-ATP affinity and catalyzed the transfer of residues S192 and D193 to Asp, promoting T379L/A380 M enzyme activity. However, the mutation did not cause fluctuations in the substrate Asp and ATP pockets. This might be why the enzyme activity was inferior to that of the single mutants (T379L and A380 M).

Summary: To improve the treatment of pigmentation disorders, looking for natural and safe inhibitors of melanin synthesis has become an area of research interest. The quinoa husk peptides reportedly elicit various biological activities (e.g., anti-cancer, antioxidant, anti-hypertensive, and so forth), but its effects on melanin inhibition remain unknown. In the current study, we purified quinoa husk peptides with 30 and 80% ethanol using a macroporous adsorption resin (DA201-C). Component screening revealed that the 80%-ethanol fraction (i.e., QHP fraction) contained numerous short peptides (84.41%) and hydrophobic amino acids (45.60%), while eliciting a superior tyrosinase [TYR]-inhibition rate, 2,2-diphenyl-1-picryhydrazil-scavenging rate, reducing activity, and chelating capacity compared to the 30% fraction and was thus applied in subsequent analyses. Differentially expressed genes in the QHP fraction were primarily enriched in the Akt-signaling pathways based on transcriptomics. Thus, we assessed the expression of related proteins and genes in A375 cells and rat skin cells following treatment with QHP.

Abstract Development of a genetic tool for visualization of photosynthetic bacteria (PSB) is essential for understanding microbial function during their interaction with plant and microflora. In this study, Rhodopseudomonas palustris GJ-22-gfp harboring the vector pBBR1-pckAPT-gfp was constructed using an electroporation transformation method and was used for dynamic tracing of bacteria in plants. The results showed that strain GJ-22-gfp was stable and did not affect the biocontrol function, and the Confocal Laser Scanning Microscopy (CLSM) results indicated it could successfully colonised on the surface of leaf and root of tobacco and rice. In tobacco leaves, cells formed aggregates on the mesophyll epidermal cells. While in rice, no aggregate was found. Instead, the fluorescent cells colonise the longitudinal intercellular spaces between epidermal cells. In addition, the results of strain GJ-22 on the growth promotion and disease resistance of tobacco and rice indicated that the different colonization patterns might be related to the bacteria could induce systemic resistance in tobacco.

Antibiotics are widely added to swine forage and are the main reason for the environmental accumulation of antibiotic resistance genes (ARGs) in swine manure-dwelling microorganisms. Aerobic composting (AC) and anaerobic digestion (AD) are efficient methods for converting swine manure to bio-fertilizer while degrading residual antibiotics. However, the influence of these methods on ARG accumulation and the difference in their efficiency have rarely been investigated. In this study, we explored the variations in four tetracycline antibiotics (TCs) and their associated ARGs and in microbial communities after AC and AD treatment. After full-scale manure AC and AD, the four TCs were removed effectively. AD had a higher TC removal efficiency than AC and a slower rate of TC-associated ARG accumulation. In addition, the community structure was more stable in the AC and AD manures than in untreated manure, and the relationship among microbial species also evolved into competition from mutualism after both AC and AD treatment. It was also speculated that the genera Acholeplasma and Arthrobacter were the possible hosts of tetO, tetW, and tetQ; the shift in the prokaryotic community composition and the alleviation of selective pressure by TC degradation led to decreased relative abundance of ARGs in AD- and AC-treated manure.

G-negative bacteria produce myriad N-acyl-homoserine lactones (AHLs) that can function as quorum sensing (QS) signaling molecules. AHLs are also known to regulate various plant biological activities. p-Coumaroyl-homoserine lactone C-HSL) is the only QS molecule PCproduced by a photosynthetic bacterium, Rhodopseudomonas palustris The role of PC - HSL in the interaction between R. paluxtris and plant has not been investigated. In this study. we investigated the effect of pC-HSL on plant immunity and found that this QS molecule can induce a systemic resistance to Tobacco mosaic virus (TMV) infection in Nicotiana benthamiana. The results show that PC-HSL treatment can prolong the activation of two mitogen-associated protein kinase genes (i. e., NbSIPK and NBWIPK) and increase the expression of transcription factor WRKY8 as well as immune response marker genes NbPRI and NI)PRIO. leading to Rlwan increased accumulation of reactive oxygen species ('ROS) in the TMV-infected plants. Our results also show that pC-HSL treatment can increase activities of two ROS-scavenging enzymes. peroxidase and superoxide dismutase. Knockdown of NbSIPK or NbWIPK expression in N. benthcuniana plants through virus-induced gene silencing nullified or attenuated PCproduced HSL-induced systemic resistance, indicating that the functioning of PC-HSL relies on the activity of' those two kinases. Meanwhile, PC-HSL-pretreated plants also showed a strong induction of kinase activities of NbSIPK and NbWIPK after TMV inoculation. Taken together, our results demonstrate that pC- HSL treatment increases plant resistance to TMV infection, which is helpful to uncover the outcome of interaction between R. palustris and its host plants. [ABSTRACT FROM AUTHOR]