Metabolomics and Proteomics Responses of Largemouth Bass (Micropterus salmoides) Muscle under Organic Selenium Temporary Rearing.

Organic selenium has been widely studied as a nutritional supplement for animal feed. However, there are few studies on the effect of organic selenium on flesh quality. In this study, the effects of organic selenium (yeast selenium (YS), Se 0.002 mg/L) on the metabolism and protein expression in Micropterus salmoides muscle under temporary fasting condition (6 weeks) were investigated. The muscle structure was observed through a microscope, and regulatory pathways were analyzed using proteomics and metabolomics methods. Electron microscopy showed that YS made the muscle fibers of M. salmoides more closely aligned. Differential analysis identified 523 lipid molecules and 268 proteins. The numbers of upregulated and downregulated proteins were 178 and 90, respectively, including metabolism (46.15%), cytoskeleton (11.24%) and immune oxidative stress (9.47%), etc. Integrated analyses revealed that YS enhanced muscle glycolysis, the tricarboxylic acid cycle and oxidative phosphorylation metabolism. In the YS group, the content of eicosapentaenoic acid was increased, and that of docosahexaenoic acid was decreased. YS slowed down protein degradation by downregulating ubiquitin and ubiquitin ligase expression. These results suggest that organic selenium can improve M. salmoides muscle quality through the aforementioned pathways, which provides potential insights into the improvement of the quality of aquatic products, especially fish.

Effects of temporary rearing with organic selenium on the muscle flavor and texture properties of largemouth bass (Micropterus salmonides).

In this study, the influences of organic selenium (Se, 0.002 mg/L) on the muscle flavor and texture properties of Micropterus salmonides under fasting temporary rearing (8 weeks) was investigated. Electronic nose and headspace solid-phase microextraction-gas chromatography-mass spectrometry analysis suggested that organic Se regulated the types and contents of volatile compounds, especially aldehydes and ketones, which were increased in the early temporary rearing but decreased in the late stage. Organic Se significantly increased the content of 5'-inosine monophosphate by approximately 15 % (p < 0.05), and decreased the content of hypoxanthine and hypoxanthine ribonucleoside by more than 20 % (p < 0.05). After the 8th temporary rearing week, muscle hardness and springiness increased by at least 10 % (p < 0.01), resilience and gumminess improved by at least 18 % (p < 0.05) and 5.9 % (p < 0.05), respectively. In conclusion, organic Se ameliorates the flesh quality of M. salmonides during long-term temporary rearing.

Corosolic Acid Attenuates Hepatic Lipid Accumulation and Inflammatory Response via AMPK/SREBPs and NF-κB/MAPK Signaling Pathways.

Corosolic acid (CA) is the main active component of Lagetstroemia speciosa and has been known to serve as several different pharmacological effects, such as antidiabetic, anti-oxidant, and anticancer effects. In this study, effects of CA on the hepatic lipid accumulation were examined using HepG2 cells and tyloxapol (TY)-induced hyperlipidemia ICR mice. CA significantly inhibited hepatic lipid accumulation via inhibition of SREBPs, and its target genes FAS, SCD1, and HMGCR transcription in HepG2 cells. These effects were mediated through activation of AMPK, and these effects were all abolished in the presence of compound C (CC, an AMPK inhibitor). In addition, CA clearly alleviated serum ALT, AST, TG, TC, low-density lipoprotein cholesterol (LDL-C), and increased high-density lipoprotein cholesterol (HDL-C) levels, and obviously attenuated TY-induced liver steatosis and inflammation. Moreover, CA significantly upregulated AMPK, ACC, LKB1 phosphorylation, and significantly inhibited lipin1, SREBPs, TNF-α, F4/80, caspase-1 expression, NF-κB translocation, and MAPK activation in TY-induced hyperlipidemia mice. Our results suggest that CA is a potent antihyperlipidemia and antihepatic steatosis agent and the mechanism involved both lipogenesis and cholesterol synthesis and inflammation response inhibition via AMPK/SREBPs and NF-κB/MAPK signaling pathways.

Directional culture of petroleum hydrocarbon degrading bacteria for enhancing crude oil recovery.

An oxygen-constrained system of crude oil reservoir environment was constructed to stimulate the growth of indigenous microbes, such as petroleum hydrocarbon-degrading bacteria. Addition of nitrogen and phosphorus sources was investigated for the growth of petroleum hydrocarbon-degrading bacteria. The results show that nitrates and phosphates stimulated the growth of the bacteria and promoted the biodegradation of crude oil as the sole carbon source in this process. The minimum surface tension was 29.63 mN/m when the amounts of the nitrogen (NaNO3: [Formula: see text]  = 2:1) and phosphorus (KH2PO4: NaH2PO4 = 5:2) sources added were 0.8 wt% and 1.4 wt%, respectively. Furthermore, the dominant petroleum hydrocarbon-degrading bacteria were shifted from Arcobacter in production water to Pseudomonas after the first subculture and then to Bacillus after the sixth subculture. The heteroatom groups in the crude oil were biodegraded simultaneously with normal alkanes and alkyl cyclohexanes. Addition of the nutrients resulted in microbial growth, microbial community shift, and enhanced microbial degradation.

Stimulation of indigenous microbes by optimizing the water cut in low permeability reservoirs for green and enhanced oil recovery.

Low permeability oil reservoirs are a widespread petroleum reservoir type all over the world. Therefore, methods to recover these reservoirs efficiently are of importance to guarantee energy supply. Here we report our novel stimulation of indigenous microbes by optimizing the water cut in low permeability reservoirs for green and enhanced oil recovery. We aimed to investigate the characteristics of indigenous bacterial communities with changes in water cut in reservoirs by high-throughput sequencing technology, and reveal the mechanism and characteristics of the crude oil biotreatment under different crude oil-water ratio conditions and the optimum activation time of indigenous functional microbial groups in reservoirs. The indigenous microbial metabolism products were characterized by gas chromatography mass spectrometry. Results showed that Acinetobacter (47.1%) and Pseudomones (19.8%) were the main functional genus of crude oil degradation at the optimal activation time, and can reduce the viscosity of crude oil from 8.33 to 5.75 mPa·s. The dominant bacteria genus for oil recovery after activation of the production fluids was similar to those in the reservoirs with water cut of 60-80%. Furthermore seven mechanism pathways of enhancing oil recovery by the synergistic of functional microbial groups and their metabolites under different water cut conditions in low permeability reservoirs have been established.

Occurrence and distribution of phosphorus fractions in sediments of Liangzi Lake under typical hydrodynamic conditions.

Understanding the transformation and chronological accumulation of phosphorus (P) forms under typical hydrodynamic conditions of a lake is important for clarifying the process of lake evolution and eutrophication. The occurrence and distribution of sediment P fractions (total, TP; inorganic, IP; and organic, OP), phytate content, and phytase activity at different profile depths (0-8 m) and parent material ages (0.8-11 ka BP) were examined at different ecological locations (inlet, outlet, and center) of the freshwater Liangzi Lake in Hubei Province, China. Sediment P-forms at locations of different hydrodynamic conditions increased from the inlet to the outlet. IP constituted ∼40-71% of TP, whereas the OP content was generally lower in the sediment. The two forms of IP extracted by HCl and NaOH varied quantitatively with depth and location: HCl-P ≈ NaOH-P (above 0.8 m) or HCl-P > NaOH-P (below 0.8 m) at the inlet; HCl-P > NaOH-P (above 0.8 m) and HCl-P ≈ NaOH-P (below 0.8 m) at the outlet; and HCl-P < NaOH-P at the center of the lake. Compared with labile and moderately resistant OP, moderately labile OP exhibited substantial quantitative changes and occurred at high levels. The variation trend in the phytate content coincided with that of TP, whereas phytase activity varied inversely with location. Low levels of P forms occurred in the sediment below 4.5 m and before 8.6 ka BP, consistent with the oligotrophic period of the lake. During 2-4 ka BP, the P forms first increased rapidly and then stabilized thereafter. From that time period until modern times, TP and phytate increased, whereas IP and OP decreased significantly. The results indicate that the hydrodynamic conditions of the water bodies and the sediments of different ages strongly influenced the occurrence and distribution of sediment P forms, and the sediment TP and phytate contents would be candidate indices to reflect the P input and eutrophication history of freshwater lakes.

Inhibition of melanogenesis by Xanthium strumarium L.

Xanthium strumarium L. (Asteraceae) is traditionally used in Korea to treat skin diseases. In this study, we investigated the effects of a X. strumarium stem extract on melanin synthesis. It inhibited melanin synthesis in a concentration-dependent manner, but it did not directly inhibit tyrosinase, the rate-limiting melanogenic enzyme, and instead downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase expression. MITF, the master regulator of pigmentation, is a target of the Wnt signaling pathway, which includes glycogen synthase kinase 3ß (GSK3ß) and ß-catenin. Hence, the influence of X. strumarium stem extract on GSK3ß and ß-catenin was further investigated. X. strumarium induced GSK3ß phosphorylation (inactivation), but the level of ß-catenin did not change. Moreover, a specific GSK3ß inhibitor restored X. strumarium-induced melanin reduction. Hence, we suggest that X. strumarium inhibits melanin synthesis through downregulation of tyrosinase via GSK3ß phosphorylation.

[Clinical characteristics and therapy of pan-drug resistant Acinetobacter baumannii infection].

OBJECTIVE: To analyze clinical characteristics and therapy of pan-resistant Acinetobacter baumannii (PDRAB) infection and explore the methods for effective therapy and prevention of this infection. METHODS: Nine hospitalized patients with PDRAB infection confirmed by pathogen and susceptibility testing were analyzed for the risk factors and the treatment outcomes were assessed by case analysis. RESULTS: PDRAB infections occurred mainly in patients with severe complications, most of whom had complications by diabetes or hypertension or damaged mucosal integrity due to mechanical ventilation, surgery and catheterization. The polymyxin sensitivity were 100% for these infections, but all the bacteria identified showed a antimicrobial resistance rates of 100%. The majority of the infections were acquired during hospitalization occurring mainly in the lungs; all the patients had prolonged hospitalization and received antibiotic treatments with high proportions of broad-spectrum antimicrobial agents especially third-generation cephalosporins and quinolones. Exclusive or sequential use of carbapenems and sulbactam in combination with quinolone or aminoglycoside produced favorable effects. CONCLUSIONS: The prevalence of hospital-acquired pan-resistance of PDRAB infections increased significantly in recent years, particularly in patients with high risk factors. The widespread use of broad-spectrum antibiotics may have some relevance to drug resistant occurrence. The application of carbapenems or sulbactam, or their sequential use, in combination with other agents may produce good effects.