Suppressor mutants demonstrate the metabolic plasticity of unsaturated fatty acid synthesis in Pseudomonas aeruginosa PAO1.

Pseudomonas aeruginosa PAO1 has two aerobic pathways for synthesis of unsaturated fatty acids (UFAs), DesA and DesB plus the oxygen independent FabAB pathway. The DesA desaturase acts on saturated acyl chains of membrane phospholipid bilayers whereas the substrates of the DesB desaturase are thought to be long chain saturated acyl-CoA thioesters derived from exogeneous saturated fatty acids that are required to support DesB-dependent growth. Under suitable aerobic conditions either of these membrane-bound desaturates can support growth of P. aeruginosa ∆fabA strains lacking the oxygen independent FabAB pathway. We previously studied function of the desA desaturase of P. putida in a P. aeruginosa ∆fabA ∆desA strain that required supplementation with a UFA for growth and noted bypass suppression of the P. aeruginosa ∆fabA ∆desA strain that restored UFA synthesis. We report three genes encoding lipid metabolism proteins that give rise to suppressor strains that bypass loss of the DesA and oxygen independent FabAB pathways.

Growth of Enterococcus faecalis ∆plsX strains is restored by increased saturated fatty acid synthesis.

The Enterococcus faecalis acyl-acyl carrier protein (ACP) phosphate acyltransferase PlsX plays an important role in phospholipid synthesis and exogenous fatty acid incorporation. Loss of plsX almost completely blocks growth by decreasing de novo phospholipid synthesis, which leads to abnormally long-chain acyl chains in the cell membrane phospholipids. The ∆plsX strain failed to grow without supplementation with an appropriate exogenous fatty acid. Introduction of a ∆fabT mutation into the ∆plsX strain to increase fatty acid synthesis allowed very weak growth. The ∆plsX strain accumulated suppressor mutants. One of these encoded a truncated ß-ketoacyl-ACP synthase II (FabO) which restored normal growth and restored de novo phospholipid acyl chain synthesis by increasing saturated acyl-ACP synthesis. Saturated acyl-ACPs are cleaved by a thioesterase to provide free fatty acids for conversion to acyl-phosphates by the FakAB system. The acyl-phosphates are incorporated into position sn1 of the phospholipids by PlsY. We report the tesE gene encodes a thioesterase that can provide free fatty acids. However, we were unable to delete the chromosomal tesE gene to confirm that it is the responsible enzyme. TesE readily cleaves unsaturated acyl-ACPs, whereas saturated acyl-ACPs are cleaved much more slowly. Overexpression of an E. faecalis enoyl-ACP reductase either FabK or FabI which results in high levels of saturated fatty acid synthesis also restored the growth of the ∆plsX strain. The ∆plsX strain grew faster in the presence of palmitic acid than in the presence of oleic acid with improvement in phospholipid acyl chain synthesis. Positional analysis of the acyl chain distribution in the phospholipids showed that saturated acyl chains dominate the sn1-position indicating a preference for saturated fatty acids at this position. High-level production of saturated acyl-ACPs is required to offset the marked preference of the TesE thioesterase for unsaturated acyl-ACPs and allow the initiation of phospholipid synthesis.

Environmental damage cost assessment from municipal solid waste treatment based on LIME3 model.

Environmental damage cost can measure the impact of pollution caused by human activity on final safeguard subjects from endpoint perspective. Application of environmental damage cost to municipal solid waste (MSW) management is still rare. To fill such a research gap, this study established a MSW environmental damage cost assessment method using Life Cycle Impact Assessment Method based on Endpoint (LIME) model. Four types of environmental damage cost, namely, primary productivity, social assets, biodiversity and human health for waste treatment were investigated in the city of Shanghai. Results show that the environmental damage cost was 113.7, 116.9, 140.0, 144.0 and 170.8 million dollars in Shanghai from 2014 to 2018, respectively. Damage cost of social assets was the dominant component, accounting for about 55%. Landfill mainly caused social assets damage cost, while incineration mainly caused human health damage cost. Scenarios analysis further revealed that after implementing MSW separation, the total environmental damage cost could be reduced by about 1/3. The best MSW treatment method is fermentation, followed by compost, incineration and landfill, with unit environmental damage cost being 0.22, 4.51, 16.04 and 23.47 USD/ton, respectively.

A bibliometric analysis on waste electrical and electronic equipment research.

Waste electrical and electronic equipment (WEEE) contains both toxic and valuable materials. Due to rapid development of information and communication technologies (ICT), a large amount of WEEE have been produced, leading to increasing academic efforts in this field. This study aims to depict the trends and features of WEEE-related studies through a bibliometric analysis. The results show that the total number of WEEE-related publications had sharply increased, with China as the leading country. University of Chinese Academy of Sciences is the most productive WEEE-related research institution, while Mai BX is the most productive author. As such, Waste Management, Journal of Cleaner Production, and Environmental Science & Technology are the most influential journals. The research hotspots of WEEE mainly focus on the recycling and treatment technologies, environmental impacts, and relevant policies of WEEE. By tracing the evolutionary pathway of WEEE research, it is clear that the research frontiers have switched from electronic equipment, extended producer responsibility, sediment, environment and design, risk assessment to life cycle assessment, mobile phone, and behaviors. This study provides valuable insights to those WEEE-related scholars so that they can identify their own research topics and partners. This paper is one of the first studies in WEEE research field that offers critical discussions and suggestions related to research development and future trends, and used visualized tools to present the holistic picture of this field.

Novel Xanthomonas campestris Long-Chain-Specific 3-Oxoacyl-Acyl Carrier Protein Reductase Involved in Diffusible Signal Factor Synthesis.

The precursors of the diffusible signal factor (DSF) family signals of Xanthomonas campestris pv. campestris are 3-hydroxyacyl-acyl carrier protein (3-hydroxyacyl-ACP) thioesters having acyl chains of 12 to 13 carbon atoms produced by the fatty acid biosynthetic pathway. We report a novel 3-oxoacyl-ACP reductase encoded by the X. campestris pv. campestris XCC0416 gene (fabG2), which is unable to participate in the initial steps of fatty acyl synthesis. This was shown by the failure of FabG2 expression to allow growth at the nonpermissive temperature of an Escherichia colifabG temperature-sensitive strain. However, when transformed into the E. coli strain together with a plasmid bearing the Vibrio harveyi acyl-ACP synthetase gene (aasS), growth proceeded, but only when the medium contained octanoic acid. In vitro assays showed that FabG2 catalyzes the reduction of long-chain (≥C8) 3-oxoacyl-ACPs to 3-hydroxyacyl-ACPs but is only weakly active with shorter-chain (C4, C6) substrates. FabG1, the housekeeping 3-oxoacyl-ACP reductase encoded within the fatty acid synthesis gene cluster, could be deleted in a strain that overexpressed fabG2 but only in octanoic acid-supplemented media. Growth of the X. campestris pv. campestris ΔfabG1 strain overexpressing fabG2 required fabH for growth with octanoic acid, indicating that octanoyl coenzyme A is elongated by X. campestris pv. campestrisfabH Deletion of fabG2 reduced DSF family signal production, whereas overproduction of either FabG1 or FabG2 in the ΔfabG2 strain restored DSF family signal levels.IMPORTANCE Quorum sensing mediated by DSF signaling molecules regulates pathogenesis in several different phytopathogenic bacteria, including Xanthomonas campestris pv. campestris DSF signaling also plays a key role in infection by the human pathogen Burkholderia cepacia The acyl chains of the DSF molecules are diverted and remodeled from a key intermediate of the fatty acid synthesis pathway. We report a Xanthomonas campestris pv. campestris fatty acid synthesis enzyme, FabG2, of novel specificity that seems tailored to provide DSF signaling molecule precursors.

Wrist-ankle acupuncture and ginger moxibustion for preventing gastrointestinal reactions to chemotherapy: A randomized controlled trial.

OBJECTIVE: To evaluate the effects of wrist-ankle acupuncture combined with ginger moxibustion against gastrointestinal tract reactions (nausea, vomiting, and constipation) to chemotherapy in cancer patients. METHODS: A total of 60 patients with gynecological tumors treated by chemotherapy were randomly divided into two groups. The treatment group (30 cases) underwent wrist-ankle acupuncture and ginger moxibustion, whereas tropisetron hydrochloride and dexamethasone were intravenously administered to the control group (30 cases) during chemotherapy. RESULTS: The frequency of nausea in the treatment group was significantly less than that of the control group from the 2nd to the 5th day of chemotherapy (P<0.01). The anti-emetic effect in the treatment group was significantly better than that in the control group on the 3rd day of therapy (P<0.05). The incidence rate of constipation was significantly lower in the treatment group than that in the control group (P<0.01). Furthermore, the cost of therapy for the treatment group was significantly lower than that of the control group (P<0.01). Only 1 patient manifested a post-acupuncture side effect in the form of subcutaneous blood stasis. CONCLUSION: Wrist-ankle acupuncture combined with ginger moxibustion could prevent gastrointestinal tract reactions to chemotherapy in cancer patients. In addition, the proposed method had fewer side effects, lower cost, and less risk.

Wrist-ankle acupuncture for pain after transcatheter arterial chemoembolization in patients with liver cancer: a randomized controlled trial.

This study was designed to evaluate the analgesic effect of wrist-ankle acupuncture (WAA) for patients with primary liver cancer (PLC) after transcatheter arterial chemoembolization (TACE). Sixty PLC patients with post-TACE visual analog pain intensity scores greater than 3 were divided equally into two groups receiving either WAA or oral morphine sulphate (MOR) for post-TACE pain. Pain intensity scores were reassessed at 1, 2, 4, and 6 h after analgesic intervention. Patients were also monitored for adverse reactions to analgesic treatment. Pain scores recorded when the patients first felt pain after TACE showed no statistical difference between the two groups (p > 0.05). WAA and MOR had indistinguishable degrees of pain relief 1, 2, and 4 h after analgesic intervention (p > 0.05). At 6 h after intervention, the WAA group experienced significantly greater pain relief than the MOR group (p < 0.05). Incidence of abdominal distension was lower in the WAA group than in the MOR group (p < 0.05). The results suggest that WAA not only had an analgesic effect equal to or greater than MOR in PLC patients with moderate to severe post-TACE pain, but also reduced the incidence of post-operative abdominal distention.

[Effects of Chinese herbal medicine Neiyi Recipe-medicated serum on angiopoiesis of endometriosis in the chick chorioallantoic membrane model].

OBJECTIVE: To compare angiopoiesis ability of eutopic and ectopic endometrial tissue isolated from women with endometriosis and endometrium isolated from women without endometriosis (control), and to explore the inhibitory effects of medicated serum of Neiyi Recipe, a compound traditional Chinese herbal medicine. METHODS: Chick chorioallantoic membrane (CAM) model of endometriosis was established by transplanting endometrium onto CAM. The CAMs were then hatched with blank serum or medicated serum of danazol or Neiyi Recipe, which were prepared in rats by orally administering. The sizes of the transplanted tissue and new vessels around the transplanted tissue were measured. Expression of vascular endothelial growth factor (VEGF) was detected by immunohistochemical method. RESULTS: There was no difference in the sizes of transplanted tissue among CAM models of ectopic and eutopic endometrial tissue isolated from women with endometriosis or control (P>0.05), and more new vessels were found around the ectopic and eutopic endometrial tissue than the endometrial tissue of control (P<0.05). Compared with the controls, the size of the transplanted tissue and positive area of new vessels were significantly inhibited by Neiyi Recipe-medicated serum (P<0.01, P<0.05), and similar changes happened in the danazol groups, except for the size of transplanted tissue from ectopic endometrial tissue (P>0.05). Expression of VEGF was significantly higher in eutopic and ectopic endometrial tissue than in the control (P<0.01); the level of VEGF obviously reduced in the Neiyi Recipe and danazol groups (P<0.01), but no significant difference was detected between them. CONCLUSION: Endometrium from women with endometriosis stimulates the formation of new vessels by increase the expression of VEGF. Neiyi Recipe-medicated serum significantly decreases the expression of VEGF in eutopic and ectopic endometrial tissues and thus restrains the formation of new vessels, reduces the blood supply and inhibits growth of ectopic endometrial tissue, which are similar to danazol, but has greater efficacy in suppressing the expression of VEGF.