Genome-wide identification and expression analysis of diacylglycerol acyltransferase genes in soybean (Glycine max).

Background: Soybean (Glycine max) is a major protein and vegetable oil source. In plants, diacylglycerol acyltransferase (DGAT) can exert strong flux control, which is rate-limiting for triacylglycerol biosynthesis in seed oil formation. Methods: Here, we identified soybean DGAT genes via a bioinformatics method, thereby laying a solid foundation for further research on their function. Based on our bioinformatics analyses, including gene structure, protein domain characteristics, and phylogenetic analysis, 26 DGAT putative gene family members unevenly distributed on 12 of the 20 soybean chromosomes were identified and divided into the following four groups: DGAT1, DGAT2, WS/DGAT, and cytoplasmic DGAT. Results: The Ka/Ks ratio of most of these genes indicated a significant positive selection pressure. DGAT genes exhibited characteristic expression patterns in soybean tissues. The differences in the structure and expression of soybean DGAT genes revealed the diversity of their functions and the complexity of soybean fatty acid metabolism. Our findings provide important information for research on the fatty acid metabolism pathway in soybean. Furthermore, our results will help identify candidate genes for potential fatty acid-profile modifications to improve soybean seed oil content. Conclusions: This is the first time that in silico studies have been used to report the genomic and proteomic characteristics of DGAT in soybean and the effect of its specific expression on organs, age, and stages.

Quantitative proteomic and lipidomics analyses of high oil content GmDGAT1-2 transgenic soybean illustrate the regulatory mechanism of lipoxygenase and oleosin.

KEY MESSAGE: Proteomic and lipidomics analyses of WT and GmDGAT1-2 transgenic soybeans showed that GmDGAT1-2 over-expression induced lipoxygenase down-regulatation and oleoin up-regulatation, which significantly changed the compositions and total fatty acid. The main goal of soybean breeding is to increase the oil content. Diacylglycerol acyltransferase (DGAT) is a key rate-limiting enzyme in fatty acid metabolism and may regulate oil content. Herein, 10 GmDGAT genes were isolated from soybean and transferred into wild-type (WT) Arabidopsis. The total fatty acid was 1.2 times higher in T3 GmDGAT1-2 transgenic Arabidopsis seeds than in WT. Therefore, GmDGAT1-2 was transferred into WT soybean (JACK), and four T3 transgenic soybean lines were obtained. The results of high-performance gas chromatography and Soxhlet extractor showed that, compared with those of JACK, oleic acid (18:1), and total fatty acid levels in transgenic soybean plants were much higher, but linoleic acid (18:2) was lower than WT. Palmitic acid (16:0), stearic acid (18:0), and linolenic acid (18:3) were not significantly different. For mechanistic studies, 436 differentially expressed proteins (DEPs) and 180 differentially expressed metabolites (DEMs) were identified between WT (JACK) and transgenic soybean pods using proteomic and lipidomics analyses. Four lipoxygenase proteins were down-regulated in linoleic acid metabolism while four oleosin proteins were up-regulated in the final oil formation. The results showed an increase in the total fatty acid and 18:1 composition, and a decrease in the 18:2 composition of fatty acid. Our study brings new insights into soybean genetic transformation and the deep study of molecular mechanism that changes the total fatty acid, 18:1, and 18:2 compositions in GmDGAT1-2 transgenic soybean.

Icariin, Formononetin and Caffeic Acid Phenethyl Ester Inhibit Feline Calicivirus Replication In Vitro.

Cats infected with feline calicivirus (FCV) often display oral ulcers and inflammation of the upper respiratory tract, which can lead to death in severe cases. Antiviral therapy is one of the most effective ways to control FCV infection. Natural compounds in Chinese herbal medicines and medicinal plants provide abundant resources for research on antiviral drugs. In this study, we found that icariin (ICA), formononetin (FMN) and caffeic acid phenethyl ester (CPAE) show low cytotoxicity towards F81 cells, that the three natural compounds have apparent antiviral effects on FCV in vitro, and that they can inhibit different FCV strains. Then, we found that ICA and FMN mainly function in the early stage of FCV infection, while CAPE can function in both the early and late stages of FCV infection. Finally, we found that ICA has an antagonistic effect on FMN and CAPE in FCV infection, and FMN has a synergistic effect with CAPE against FCV infection. Our results showed that ICA, FMN and CAPE may be potential drug candidates for FCV-induced diseases.

Neuroprotective Effects of Electroacupuncture Preventive Treatment in Senescence-Accelerated Mouse Prone 8 Mice.

OBJECTIVE: To investigate the preventive treatment effects of electroacupuncture (EA) on cognitive changes and brain damage in senescence-accelerated mouse prone 8 (SAMP8) mice. METHODS: The 5-month-old male SAMP8 and age-matched homologous normal aging mice (SAMR1) were adopted in this study. EA stimulation at Baihui (GV 20) and Yintang (EX-HN 3) was performed every other day for 12 weeks, 4 weeks as a course. Morris water maze test and Nissl-stained with cresyl violet were used for cognitive impairments evaluation and brain morphometric analysis. Amyloid-ß (A ß) expression in hippocampus and parietal cortex was detected by immunohistochemistry, and apoptosis was observed by TUNEL staining. RESULTS: After 3 courses of EA preventive treatment, the escape latencies of 8-month-old SAMP8 mice in EA group were significantly shortened than those of un-pretreated SAMP8 mice. Compared with SAMR1 mice, extensive neuronal changes were visualized in the CA1 area of hippocampus in SAMP8 mice, while these pathological changes and attenuate cell loss in hippocampal CA1 area of SAMP8 mice markedly reduced after EA preventive treatment. Furthermore, A ß expression in hippocampus and parietal cortex of SAMP8 mice decreased significantly after EA treatment, and neuronal apoptosis decreased as well. CONCLUSION: EA preventive treatment at GV 20 and EX-HN 3 might improve cognitive deficits and neuropathological changes in SAMP8 mice, which might be, at least in part, due to the effects of reducing brain neuronal damage, decreasing neuronal apoptosis and inhibiting A ß-containing aggregates.

[Effects of Influent C/N Ratios on Denitrifying Phosphorus Removal Performance Based on ABR-MBR Combined Process].

An ABR-MBR integrated reactor based on a combination of the anaerobic baffled reactor (ABR) with the microbial phase separation and membrane bioreactor (MBR) with high-effect entrapment was constructed and the circulation and interactivity of the combined process were examined by adding nitrate recycling and sludge reflux. By increasing the influent COD to adjust the COD/TN ratio, the influence of the mechanism on the denitrifying phosphorus removal performance under the condition of continuous-flow was investigated. The results showed that the average effluent concentration of soluble phosphorus under different influent C/N conditions were 0.22, 0.34, 0.39, 0.42, and 2.45 mg·L-1 and the low influent C/N ratio was beneficial to phosphate removal. When the influent C/N was 4.8-6.0, the average removal rates of COD, TN, and soluble PO43--P were more than 87%, 76%, and 93%. In addition, when the influent C/N ratio was 3.6-6.0, the removal of TN was proportional to the anoxic phosphorus uptake of ABR and conducive to the removal of TN after increasing the influent COD concentration. Higher C/N ratios of the influent improved the removal of TN at this stage. Finally, the C/N ratio of 6 was suggested to achieve the simultaneous removal of nitrogen and phosphorus.

[Optimization of Denitrifying Phosphorus Removal Performance Based on ABR-MBR Combined Process].

An integrated process based on combination of the anaerobic baffled reactor(ABR)-membrane bioreactor(MBR) was adopted to treat domestic sewage with low C/N ratio. In order to realize the function of highly efficient denitrifying phosphorus removal, nitrate recycling ratio and sludge recycle ratio were optimized in this study. The results indicated that the optimized denitrifying phosphorus removal efficiency was achieved under the conditions of organic loading rate of 2.0 kg·(m3·d)-1 in ABR, total hydraulic retention time (HRT) of ABR-MBR at 9 h, the SRT at 15 d, sludge reflux ratio of 100%, and nitrate recycling ratios set to 300%. The average removal rates of TN and soluble PO43--P were 84% and 94%, the amount of phosphorus removed by denitrifying accounted for 87% of the total phosphorus removed, and the average effluent concentration for TN and soluble phosphorus were 12.98 mg·L-1 and 0.43 mg·L-1 respectively.