Search

The unicellular alga Dunaliella bardawil is a highly salt-tolerant organism, capable of accumulating glycerol, glycine betaine and β-carotene under salt stress, and has been considered as an excellent model organism to investigate the molecular mechanisms of salt stress responses. In this study, several carotenogenic genes (DbCRTISO, DbZISO, DbLycE and DbChyB), DbBADH genes involved in glycine betaine synthesis and genes encoding probable WRKY transcription factors from D. bardawil were isolated, and promoters of DbCRTISO and DbChyB were cloned. The promoters of DbPSY, DbLycB, DbGGPS, DbCRTISO and DbChyB contained the salt-regulated element (SRE), GT1GMSCAM4, while the DbGGPS promoter has another SRE, DRECRTCOREAT. All promoters of the carotenogenic genes had light-regulated elements and W-box cis-acting elements. Most WRKY transcription factors can bind to the W-box, and play roles in abiotic stress. qRT-PCR analysis showed that salt stress up-regulated both carotenogenic genes and WRKY transcription factors. In contrast, the transcription levels of DbBADH showed minor changes. In D. bardawil, it appears that carotenoid over-accumulation allows for the long-term adaptation to salt stress, while the rapid modulation of glycine betaine biosynthesis provides an initial response.

AMP-forming acetyl-CoA synthetase (ACS) catalyzes the formation of acetyl-CoA. Here, a cDNA of ACS from Dunaliella tertiolecta (DtACS) was isolated using RACEs. The full-length DtACS cDNA (GenBank: KT692941) is 2,464 bp with a putative ORF of 2,184 bp, which encodes 727 amino acids with a predicted molecular weight of 79.72 kDa. DtACS has a close relationship with Chlamydomonas reinhardtii and Volvox carteri f. nagariensis. ACSs existing in Bacteria, Archaea and Eukaryota share ten conserved motifs (A1–A10) and three signature motifs (I–III) of the acyl-adenylate/thioester forming enzyme superfamily. DtACS was expressed in E. coli BL21 as Trx-His-tagged fusion protein (~100 kDa) and the enzymatic activity was detected. The recombinant DtACS was purified by HisTrapTM HP affinity chromatography to obtain a specific activity of 52.873 U/mg with a yield of 56.26%, which approached the specific activity of ACS isolated from other eukaryotes. Kinetic analysis indicated that the Km of DtACS was 3.59 mM for potassium acetate and the purified DtACS exhibited a temperature optimum of 37 °C and a pH optimum of 8.0. In addition, the expression levels of DtACS were increased after nitrogen starvation cultivation, indicating that ACS activity may be related to the lipid accumulation under nitrogen deficient condition.

Background Severely destructive disasters can often lead to heavy casualties. Large arterial injury in disasters, particularly, often results in high mortality and morbidity. Although minimally invasive intervention has achieved positive effects in diagnosing and treating vascular injuries, it is still unavailable at the disaster area of any country due to lack of on-spot catheterization labs. This study aimed to test the feasibility of adopting interventional techniques to treat haemorrhage of large arterial injuries in remote and austere wild environments after severely destructive disasters, by using a new mobile intervention suite we developed—the mobile minimally invasive interventional shelter (MIS). Methods Large animal models of aortic and femoral arterial injuries were established using a newly developed medium vehicle-mounted digital subtraction angiography (DSA) machine in MIS. The endovascular stent-graft exclusion and balloon occlusion combined with surgical hemostasis were performed respectively following the protocols for rapid interventional therapy. The treatment capacity of the shelter was evaluated based on its stability, surgery duration and the clinical results. Results and discussion The stability of the medical devices in MIS directly relates to the efficiency and success rate of interventional treatment. The newly developed vehicle-mounted DSA machine showed good imaging performance and the operation of all equipments and devices in MIS were stable in interventional procedures. All the interventional treatments for large arterial injuries were performed smoothly. The average time for treating abdominal aortic injury and femoral arterial injury was 23 ± 11 and 55 ± 17 min, respectively. And the operation success rate reached 100 %. Conclusion It is feasible to perform interventional operations to control haemorrhage of large arterial injuries in MIS outside hospital. The MIS has a great potential to save patients from dying of hemorrhagic shock due to lack of effective treatment devices and approaches in remote and austere wild environments, such as in disaster areas.

Background There has been an increase in natural disasters in recent years, which leads to a great number of injuries and deaths. It still remains an unsolved problem to treat patients with vascular injury of solid organs effectively following natural disasters, but on-spot emergency interventional transcatheter arterial embolization (TAE) has been highly recommended to cure serious vascular injury of solid organs nowadays. Spleen is the most vulnerable abdominal organ, severe arterial hemorrhage of which can cause death if untreated timely. In this research, we aimed to study the possibility of performing emergency surgical intervention in mobile minimally invasive interventional shelter for splenic injury in the case of natural disasters. Methods First, the mobile minimally invasive interventional shelter was unfolded in the field, and then disinfection and preoperative preparation were performed immediately. Eight large animal models of splenic injury were created, and angiograms were performed using a digital subtraction angiography machine in the mobile minimally invasive interventional shelter, and then the hemostatic embolizations of injured splenic artery were performed following the established convention of rapid intervention therapy. The operating time was recorded, and the survival condition and postoperative complications were observed for two weeks. Results and discussion The average time of unfolding the shelter, and performing disinfection and preoperative preparation was 33 ± 7 min. The number of colonies in the sterilized shelter body was 86 ± 13 cfu/m3. The average TAE time was 31 ± 7 min. All the hemostatic embolizations of splenic injury were performed successfully in the mobile minimally invasive interventional shelter during the operation. A pseudoaneurysm was found in an animal model using angiography two weeks after the operation. The primary clinical success rate of embolization was 87.5%. The two-week survival rate in all animal models of splenic injury was 100%. Conclusions Our findings in the current study demonstrate that the mobile minimally invasive interventional shelter can be adapted to the field perfectly and complete emergency surgical intervention for splenic injury efficiently and safely. Therefore, on-spot emergency interventional TAE for vascular injury of solid organs (e.g. spleen) in mobile minimally invasive interventional shelter is available and effective.

To decrease the methanol content of the sugar cane sprits, mutagenesis of ultraviolet (UV) coupled with diethyl sulfate (DES) was used to generate a mutant of Saccharomyces cerevisiae with lower methanol content. Meanwhile, the effects of the additions of pectinase, cellulase and glycine on the production of methanol in sugar cane spirits were evaluated.After mutagenesis of UV coupled with DES, a mutant S. cerevisiae DU9 with low production of methanol (97.3 ± 1.7 mg/L) was selected, with a 12.3% decrease of that of S. cerevisiae D4 only with DES treatment, and with a 27.8% reduction of that of the strain without any treatment. Pectinase and cellulase significantly increased the methanol levels of the sugar cane spirits. The results showed that there was linear relationship between glycine (concentration within 0∼0.9 g/L) and methanol in sugar cane sprits and the linear equation was y = 104.7 × -4.79 with the conversion rate of glycine conversion to methanol as 24.56%.Mutagenesis of UV coupled with DES is an efficient way to generate a mutant of S. cerevisiae with lower methanol content. Also, it is necessary to control the additions of pectinase, cellulase and glycine in the fermentation medium, and other unknown ways to generate methanol metabolic pathway in yeasts may need further study.

Methanol, often generated in brewed wine, is highly toxic for human health. To decrease the methanol content of the brewed wine, atmospheric and room-temperature plasma (ARTP) was used as a new mutagenesis tool to generate a mutant of Saccharomyces cerevisiae with lower methanol content. Headspace gas chromatography was used to determine the identity and concentration of methanol with butyl acetate as internal standard in brewed wine. With 47.4% higher and 26.3% positive mutation rates were obtained, the ARTP jet exhibited a strong effect on mutation breeding of S. cerevisiae. The mutant S. cerevisiae S12 exhibited the lowest methanol content, which was decreased by 72.54% compared with that of the wild-type strain. Subsequently, the mutant S. cerevisiae S12 was used to ferment different combinations of malt and adjuncts for lower methanol content and higher alcoholic content. It was shown that the culture 6#, which was 60% malt, 20% wheat, and 20% corn, was the best combinations of malt and adjuncts, with the lowest methanol content (104.8 mg/L), and a relatively higher alcoholic content (15.3%, v/v). The optimal malt-adjunct culture 6#, treated with the glucoamylase dose of 0.04 U/mg of grain released the highest reducing sugars (201.6 mg/mL). It was indicated that the variation in reducing sugars among the combinations of malt and different adjuncts could be due to the dose of exogenous enzymes.

With the depletion of global petroleum and its increasing price, biodiesel has been becoming one of the most promising biofuels for global fuels market. Researchers exploit oleaginous microorganisms for biodiesel production due to their short life cycle, less labor required, less affection by venue, and easier to scale up. Many oleaginous microorganisms can accumulate lipids, especially triacylglycerols (TAGs), which are the main materials for biodiesel production. This review is covering the related researches on different oleaginous microorganisms, such as yeast, mold, bacteria and microalgae, which might become the potential oil feedstocks for biodiesel production in the future, showing that biodiesel from oleaginous microorganisms has a great prospect in the development of biomass energy. Microbial oils biosynthesis process includes fatty acid synthesis approach and TAG synthesis approach. In addition, the strategies to increase lipids accumulation via metabolic engineering technology, involving the enhancement of fatty acid synthesis approach, the enhancement of TAG synthesis approach, the regulation of related TAG biosynthesis bypass approaches, the blocking of competing pathways and the multi-gene approach, are discussed in detail. It is suggested that DGAT and ME are the most promising targets for gene transformation, and reducing PEPC activity is observed to be beneficial for lipid production.