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1.
World J Microbiol Biotechnol ; 36(12): 182, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33170386

RESUMO

Lactate are proved to be attractive electron donor for the production of n-caproic acid (CA) that is a high value-added fuel precursor and chemical feedstock, but little is known about molecular mechanism of lactate transformation. In the present study, the gene for L-lactate dehydrogenase (LDH, EC.1.1.1.27) from a Ruminococcaceae strain CPB6 was cloned and expressed in Escherichia coli BL21 (DE3) with plasmid pET28a. The recombinant LDH exhibited molecular weight of 36-38 kDa in SDS-PAGE. The purified LDH was found to have the maximal oxidation activity of 29.6 U/mg from lactate to pyruvate at pH 6.5, and the maximal reduction activity of 10.4 U/mg from pyruvate to lactate at pH 8.5, respectively. Strikingly, its oxidative activity predominates over reductive activity, leading to a 17-fold increase for the utilization of lactate in E. coli/pET28a-LDH than E. coli/pET28a. The CPB6 LDH gene encodes a 315 amino acid protein sharing 42.19% similarity with Clostridium beijerinckii LDH, and lower similarity with LDHs of other organisms. Significant difference were observed between the CPB6 LDH and C. beijerinckii and C. acetobutylicum LDH in the predicted tertiary structure and active center. Further, X-ray crystal structure analysis need to be performed to verify the specific active center of the CPB6 LDH and its role in the conversion of lactate into CA.

2.
Ocul Immunol Inflamm ; : 1-6, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33185484

RESUMO

PURPOSE: To summarize the clinical features and probable factors associated with recurrence within 6 months in northern Chinese ocular toxocariasis (OT) patients. METHODS: A retrospective cohort study (38 OT eyes) was conducted. Clinical features, aqueous inflammatory cytokines, complications, and parameters associated with recurrence after treatment were analyzed. RESULTS: The initial best-corrected visual acuity (BCVA) was related to the anterior inflammation grade at the onset (P = .028). The mean BCVA and anterior inflammation improved significantly (P < .05) after treatment. The OT eyes had higher aqueous humor cytokine levels (IL-6, IL-8, and IL-10) compared with the normal eyes (P < .001). More severe anterior inflammation grade or longer duration of uveitis were more likely to increase the probability of recurrence (P = .008 and P = .025), TA injection during/after vitreous surgery can reduce the probability of recurrence (P = .031). CONCLUSIONS: The combination therapy of vitreoretinal surgery, steroids, and albendazole therapy may reduce inflammation and recurrence of OT effectively. Abbreviations: BCVA: best-corrected visual acuity; BFGF: basic fibroblast growth factor; CFT: central foveal thickness; CI: confidence interval; ELISA: Enzyme-linked immunosorbent assay; ERM: epiretinal membrane; IOP: intraocular pressure; IQR: interquartile range; IL: interleukin; LFM: laser flare meter; MH: macular hole; OCT: optical coherence tomography; OR: odds ratio; OT: ocular toxocariasis; RD: retinal detachment; TA: triamcinolone acetonide; TCLA: Toxocara canis larva crude antigen; TGF: transforming growth factor; VCAM: vascular cell adhesion molecule; VEGF: vascular endothelial growth factor.

3.
Neurobiol Aging ; 96: 267-276, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-33130544

RESUMO

This study investigated the impact of white matter hyperintensities (WMHs) on the progression from mild parkinsonian signs (MPS) to parkinsonism and Parkinson's disease (PD). Participants with MPS completed 5 years of follow-up. WMHs were divided into periventricular WMHs and deep WMHs according to magnetic resonance imaging scans. The diagnosis of MPS, parkinsonism, and PD was based on the motor portion of the Unified Parkinson's Disease Rating Scale. Cox proportional hazard models were used to identify the association between WMHs and MPS progression. Of the 636 participants, 166 (26.1%) with MPS developed parkinsonism and PD after follow-up. After adjusting for potential factors, severe WMHs were associated with an increased risk of MPS progression, moderate and severe periventricular WMHs and severe deep WMHs were associated with the risk of MPS progression, and severe WMHs were associated with the progression of gait/balance impairment, bradykinesia, and rigidity. Additionally, participants treated for vascular risk factors such as hypertension, diabetes mellitus, and hypercholesterolemia had a lower risk of MPS progression.

4.
Dermatol Surg ; 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33038103

RESUMO

BACKGROUND: Stable vitiligo has been treated by dermabrasion and noncultured epidermal cell suspension (NCES) effectively. However, not all patches respond well. OBJECTIVE: To investigate the efficacy of new pigmentation after medical treatment in the therapy of stable vitiligo. MATERIALS AND METHODS: Medical records were retrospectively reviewed from October 2016 to March 2019, and 134 patients with stable vitiligo after medical therapy were further treated with NCES. They were divided into 2 groups: 70 patients in Group 1 had new pigmentation, whereas 64 patients in Group 2 did not. Repigmentation and satisfaction of patients and third-party assessors were evaluated at 3 and 6 months postoperatively. RESULTS: Repigmentation was scored as excellent (≥76%), good (51%-75%), fair (26%-50%), or poor (≤25%). Repigmentation of the 2 groups at 6 months postoperatively was excellent in 82.9% versus 23.4%, good in 10.0% versus 15.6%, fair in 7.1% versus 13.0%, and poor in 0% versus 48.4%, respectively. A positive correlation between satisfaction and repigmentation was found. CONCLUSION: New pigmentation after medical treatment suggests increased efficacy of NCES in treating stable vitiligo.

5.
Food Chem ; 341(Pt 2): 128288, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33039738

RESUMO

In this study, fermentations were performed using simulated grape juice supplemented with terpene glycosides (TGs), extracted from Vitis vinifera L. Meili, and phenolic acids (gallic acid or p-coumaric acid). Free terpenes were detected using solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) every day during the fermentation, and the aromas of final wines were evaluated by panelists. Quantum mechanical (QM) calculations performed at density functional level of theory were used to uncover the structural and thermodynamic properties of the binding between phenolic acids and free terpenes (or TGs). Results showed that phenolic acids remarkably inhibited TG hydrolysis and free terpene volatilization, and affected wine aroma perception. QM calculations revealed that phenolic acids can bind to linalool and its glycoside spontaneously (ΔG < 0) via hydrogen bonding and dispersive forces. These findings indicate that the matrix effect of phenolic acids can effectively control the release and modulate the global feature of wine aromas.

6.
Int J Colorectal Dis ; 2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32865713

RESUMO

INTRODUCTION: Endoscopic migration of plastic biliary stents is performed by endoscopic retrograde cholangiopancreatography (ERCP) for biliary and pancreatic diseases. This plays an increasingly important role. Intestinal perforation caused by stent migration is one of the complications. Although sigmoid colon perforation caused by stent migration is rare, it can be life-threatening. This case shows us that we should increase awareness of sudden abdominal pain after ERCP. METHOD: We provide a review of the clinical manifestations, imaging data of this case, and the literature related to the perforation caused by stent migration. RESULTS: A male patient had a history of choledocholithiasis, cholecystolithiasis, and biliary pancreatitis treated with ERCP and a pancreatic stent. After the operation, the patient developed cholangitis and was treated with ERCP and a plastic biliary stent. This patient was admitted to the emergency department with sudden lower abdominal pain. A CT scan showed sigmoid colon perforation by a foreign body and infra-diaphragmatic free air. An emergency surgery confirmed that the stent had caused the perforation. The patient was then treated with sigmoid colectomy and sigmoidostomy. DISCUSSION: Biliary stent migration after ERCP is rare, but intestinal perforation caused by migration should be considered in cases of abdominal pain of unknown cause.

7.
Neural Plast ; 2020: 8843485, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32908487

RESUMO

Sensorineural hearing loss (SNHL) becomes an inevitable worldwide public health issue, and deafness treatment is urgently imperative; yet their current curative therapy is limited. Auditory neuropathies (AN) were proved to play a substantial role in SNHL recently, and spiral ganglion neuron (SGN) dysfunction is a dominant pathogenesis of AN. Auditory pathway is a high energy consumption system, and SGNs required sufficient mitochondria. Mitochondria are known treatment target of SNHL, but mitochondrion mechanism and pathology in SGNs are not valued. Mitochondrial dysfunction and pharmacological therapy were studied in neurodegeneration, providing new insights in mitochondrion-targeted treatment of AN. In this review, we summarized mitochondrial biological functions related to SGNs and discussed interaction between mitochondrial dysfunction and AN, as well as existing mitochondrion treatment for SNHL. Pharmaceutical exploration to protect mitochondrion dysfunction is a feasible and effective therapeutics for AN.

8.
Oncogene ; 39(43): 6704-6718, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32958832

RESUMO

Autophagy can protect stressed cancer cell by degradation of damaged proteins and organelles. However, the regulatory mechanisms behind this cellular process remain incompletely understood. Here, we demonstrate that RSK2 (p90 ribosomal S6 kinase 2) plays a critical role in ER stress-induced autophagy in breast cancer cells. We demonstrated that the promotive effect of RSK2 on autophagy resulted from directly binding of AMPKα2 in nucleus and phosphorylating it at Thr172 residue. IRE1α, an ER membrane-associated protein mediating unfolded protein response (UPR), is required for transducing the signal for activation of ERK1/2-RSK2 under ER stress. Suppression of autophagy by knockdown of RSK2 enhanced the sensitivity of breast cancer cells to ER stress both in vitro and in vivo. Furthermore, we demonstrated that inhibition of RSK2-mediated autophagy rendered breast cancer cells more sensitive to paclitaxel, a chemotherapeutic agent that induces ER stress-mediated cell death. This study identifies RSK2 as a novel controller of autophagy in tumor cells and suggests that targeting RSK2 can be exploited as an approach to reinforce the efficacy of ER stress-inducing agents against cancer.

9.
Appl Microbiol Biotechnol ; 104(22): 9749-9757, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32989515

RESUMO

Cadmium (Cd) contamination has resulted in serious environmental pollution and threatens human health and ecosystems. Our recent studies have demonstrated that Pseudomonas chenduensis strain MBR can decrease Cd bio-availability and reduce Cd accumulation in rice; however, the transcriptional mechanisms underlying the bacterial response during and particularly after Cd bioremediation are still unclear. In this study, we used RNA-Seq to investigate the transcriptional profiles of strain MBR during and after Cd bioremediation. During Cd bioremediation, MBR removed all Cd2+ ions in solution within 24 h, accompanied by 564 upregulated and 363 downregulated expressed genes compared with that of the control (without Cd supplementation). Specifically, under Cd stress, the upregulation of czc (czcA, czcB, and czcC) and mer (merA, merT, merC, and merP) genes enabled Cd efflux from the cytoplasm and conferred resistance of MBR to Cd toxicity. The upregulation of genes (algK, algX, and alg44) related to biofilm formation enabled Cd absorption and contributed to Cd bioremediation. After Cd bioremediation, MBR was transferred to non-Cd medium, and the genes related to histidine metabolism and flagellar assembly still showed similar expression patterns as those during bioremediation (defined as Cd legacy effects). However, the genes involved in Cd resistance and bioremediation were not influenced by Cd legacy effects. This study provides new and thorough insights into the molecular mechanisms underlying Cd bioremediation by a functional microbe. KEY POINTS: • The upregulation of czc and mer genes is responsible for MBR resistance to Cd. • The upregulation of genes related to biofilm formation contributes to Cd bioremediation. • Cd effects on genes involved in histidine metabolism and flagellar assembly are long-lasting.

10.
Gene Ther ; 27(7-8): 406, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32778810

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

11.
Nat Commun ; 11(1): 4226, 2020 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-32839450

RESUMO

Intercellular signaling is indispensable for single cells to form complex biological structures, such as biofilms, tissues and organs. The genetic tools available for engineering intercellular signaling, however, are quite limited. Here we exploit the chemical diversity of biological small molecules to de novo design a genetic toolbox for high-performance, multi-channel cell-cell communications and biological computations. By biosynthetic pathway design for signal molecules, rational engineering of sensing promoters and directed evolution of sensing transcription factors, we obtain six cell-cell signaling channels in bacteria with orthogonality far exceeding the conventional quorum sensing systems and successfully transfer some of them into yeast and human cells. For demonstration, they are applied in cell consortia to generate bacterial colony-patterns using up to four signaling channels simultaneously and to implement distributed bio-computation containing seven different strains as basic units. This intercellular signaling toolbox paves the way for engineering complex multicellularity including artificial ecosystems and smart tissues.


Assuntos
Comunicação Celular/genética , Biologia Computacional/métodos , Transdução de Sinais/genética , Fatores de Transcrição/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , Humanos , Microscopia de Fluorescência , Mutação , Reprodutibilidade dos Testes , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo
12.
J Int Med Res ; 48(8): 300060520929865, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32776804

RESUMO

This report describes the presence of Stenotrophomonas maltophilia endophthalmitis after phacoemulsification in a 66-year-old woman. The patient presented with ocular redness and pain, as well as hypopyon in the anterior chamber and reduction of visual acuity to hand motion. Intraocular fluid examination revealed a lipopolysaccharide level of >2.5, which suggested bacterial endophthalmitis. The patient was promptly treated with intravitreal ceftazidime 2 mg and vancomycin 1 mg, as well as intravenous infusion of cefuroxime 750 mg, all administered simultaneously at 12-hour intervals. She also received topical levofloxacin eyedrops, once per hour. Subsequently, pathology culture confirmed the presence of the Gram-negative bacillus, S. maltophilia. The presence of lipopolysaccharide in intraocular fluid is an important early indicator of bacterial endophthalmitis, which can provide guidance for clinical treatment.

13.
World J Microbiol Biotechnol ; 36(9): 132, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32737601

RESUMO

Menaquinone-7 (MK-7), a highly valuable member of the vitamin K2 series, is an essential nutrient for humans. In this study, to develop engineered Escherichia coli strains for MK-7 production, heterogeneous heptaprenyl pyrophosphate synthetase (HepPPS) was introduced, and MK-7 production was first achieved in engineered E. coli by overexpression of Bacillus subtilis-derived HepPPS (BsHepPPS). Then, by optimizing the enzyme expression of the heterogenous mevalonic acid (MVA) pathway and the BsHepPPS, the titre of MK-7 increased to 2.3 µM, which was 22-fold higher than that of the original strain. The competitive pathways of MK-7 were further investigated by deletion of ubiCA or ispB. Finally, the scale-up fermentation of the engineered E. coli in a 5-L fermenter was studied under aerobic conditions using glucose, and 13.6 µM (8.8 mg/L) MK-7 was achieved. Additionally, metabolite analysis revealed a new bottleneck in the MK-7 pathway at ubiE, suggesting an avenue for further optimization. This report is the first to describe the metabolic engineering of MK-7 in E. coli, which provides a new perspective for MK-7 production.

14.
Invest Ophthalmol Vis Sci ; 61(8): 47, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32729912

RESUMO

Purpose: The aim of this study was to investigate apelin and its potential neovascularization role in retinopathy of prematurity (ROP) along with the inhibitory effects of its antagonist. Methods: We used an oxygen-induced retinopathy (OIR) mouse model to explore the progress of ROP. Apelin and angiotensin receptor-like 1 APJ expressions were examined in the retina using immunohistochemistry, quantitative polymerase chain reaction, and Western blot analysis. Additionally, the retina was examined by whole-mount staining to evaluate the retinal vessel area, vessel density, capillary width, and the number and length of tip cells. The expression of the phosphorylated mTOR (p-mTOR), p-PI3K/Akt, and p-Erk signaling pathway was also evaluated using Western blot analysis. Results: Apelin promoted the development of superficial and deep retinal blood vessels, especially for tip cells during the physical development of retinal vessels. Additionally, apelin stimulated the density of the peripheral retinal zone vessels in OIR mice. The apelin and APJ expression levels significantly increased for the OIR model during their hypoxic phase. Next, we found that apelin mRNA levels in the OIR mice peaked at six hours after return to ambient conditions at P12, whereas the APJ mRNA levels peaked later at P17. Furthermore, the expression of p-mTOR, p-Akt, and p-Erk were all up-regulated in OIR mice whereas F13A suppressed them instead. Conclusions: Our results suggest that apelin/APJ signaling pathway is a key factor for hypoxia-induced pathologic angiogenesis, which is a very promising new target for the treatment of ROP.

15.
Hear Res ; 394: 107999, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32611519

RESUMO

CRISPR/Cas9 gene editing enables the treatment of hearing loss in congenitally deaf neonatal mice via both viral and non-viral delivery. While adeno-associated virus (AAV)-mediated gene delivery systems have been shown to be effective tools for gene replacement in the inner ear, application of the AAV-mediated CRISPR/Cas9 gene-editing approach for this purpose is yet to be documented. Based on our previous findings, we focused on the effects of several AAVs delivered via canalostomy injection in adult mice. Among the AAVs examined, AAV8 showed the greatest efficiency and specificity in transducing inner hair cells (IHC). The ability of Cre-expressing AAV8 to activate Cas9 in floxed-Cas9 knock-in (Cas9 KI) mice was further evaluated. We compared the effects of six different promoters (CMV, CAG, hSyn, CaMKIIa, GFAP, and ALB) of AAV8 delivered to the inner ear of adult Cas9 KI mice. Our findings showed that three AAV groups (CMV, CAG and hSyn promoters) infected the inner ear efficiently with different tropisms. Notably, AAVs with CMV, CAG, and hSyn promoters infected diverse cell types in mature murine cochleae, including IHCs. In particular, AAV8-hSyn showed high affinity to IHCs and spiral ganglion neurons (SGN). Neither the AAV8 virus itself (except AAV8-CAG) nor the surgical procedures used caused damage to HCs or impaired normal hearing. Our findings indicated that injection of AAV-Cre into mature inner ear efficiently induces Cas9 activation to achieve safe and efficient gene editing and different constituent promoters confer diverse infection patterns in cochlea, expanding the repertoire of gene-editing tools for regulating gene expression in target cells of the inner ear as part of the collective effort to rescue genetic hearing loss and develop effective gene therapy techniques.

16.
ACS Synth Biol ; 9(8): 2066-2075, 2020 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-32702969

RESUMO

Guanidino compounds can be synthesized by transamidination reactions using arginine as a guanidine group donor. The efficiency of guanidino biosynthesis is often affected by the supply of arginine and the inhibition of the coproduct ornithine. To alleviate this shortcoming, we designed a reconstituted ornithine cycle in Escherichia coli to engineer an efficient whole-cell catalyst for guanidinoacetate (GAA) production by introducing a heterogeneous arginine:glycine amidinotransferase (AGAT). To alleviate the inhibition of ornithine, a citrulline synthetic module was constructed and optimized by introducing a glutamine self-sufficient system. Then, to improve the pathway from citrulline to arginine, an aspartate self-sufficient system was introduced into the arginine synthetic module. By combining these modules (GAA, citrulline, and arginine synthetic modules), a reconstituted ornithine cycle was developed, which significantly improved the biocatalyst efficiency (3.9-fold increase). In the system, arginine was regenerated efficiently through the reconstituted ornithine cycle, which converted arginine from a substrate to a cofactor for the transamidination reaction, thereby relieving the ornithine inhibition. Moreover, the amidino group of GAA in this system was mainly supplied by carbon and nitrogen assimilation. After the engineering process, 8.61 g/L GAA (73.56 mM) with a productivity of 0.39 g/L/h was achieved in a 22 h bioconversion. To the best of our knowledge, this is the first time that GAA has been produced in E. coli. This reconstructed ornithine cycle could be used as a transamidination platform for amidino group supply and has potential applications in the biosynthesis of other guanidino compounds.

17.
BMC Ophthalmol ; 20(1): 261, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32605612

RESUMO

BACKGROUND: Two cases with refractory macular edema secondary to adult-onset Coats' disease underwent unsatisfactory treatment by intravitreal injections of anti-vascular endothelial growth factor (VEGF) drugs and retinal photocoagulation. CASE PRESENTATION: The authors highlight the guiding effect of the measurement of cytokines in the aqueous humor for the treatment of adult-onset Coats' disease with refractory macular edema. In the two cases, typical Coats' disease changes, including telangiectasis, subretinal exudation and macular edema were observed. Initial treatment consisted of intravitreal anti-VEGF drugs and retinal laser photocoagulation; however, the response was poor. Then, the aqueous humor was acquired and the cytokine concentrations were measured (Flow Cytometry Analysis, Beijing Giantmed Medical Diagnostics Lab). When the cytokine levels were tested every time there would be quality control, with a fixed concentration of cytokines samples to detect before the results reported. A low level of VEGF and a high level of inflammatory cytokines were found. Then, treatment was switched to intravitreal injection of dexamethasone implant (Ozurdex®) (Allergan, Inc., Irvine, Calif., USA), which resulted in resolution of the refractory macular edema and improvement of visual acuity in both cases. CONCLUSIONS: For refractory macular edema secondary to adult-onset Coats' disease, measurement of the levels of VEGF and inflammatory cytokines can help clinic doctors precisely investigate the molecular mechanism of macular edema and thereby find a suitable treatment.

18.
Ocul Immunol Inflamm ; : 1-6, 2020 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32634031

RESUMO

Purpose: To analyze the clinical characteristics and relevant prognostic factors of vitrectomy for retinal detachment (RD) secondary to cytomegalovirus retinitis (CMVR) in patients with acquired immune deficiency syndrome (AIDS).Methods: This study involved 39 eyes that underwent vitrectomy. Best-corrected visual acuity (BCVA), CD4+ cell counts, retinal attachment rate, and prognostic factors were assessed 1, 3, and 6 months postoperatively.Results: The rate of retinal attachment at 1 month (87.2%) was higher than at 3 (82.1%) and 6 (71.8%) months. Factors significantly related with recurrent RD at 6 months were CD4+ cell count <50 cell/µL (p = .000) and relaxed retinotomy (p = .002). Factors significantly related with the visual (≤logMAR1.0) prognosis at 6 months include band keratopathy (p = .015) and macular involvement by the RD (p = .012).Conclusion: CD4+ cell counts <50 cell/µL and relaxed retinotomy are associated with worse prognosis, while band keratopathy and macular involvement by the RD are related to poorer vision.

19.
Food Chem ; 332: 127426, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619948

RESUMO

A selected Pichia fermentans strain was simultaneously and sequentially inoculated in synthetic and real juice with S. cerevisiae strains of different antagonistic activities in a ratio 1:1 to observe the correlation between varietal odorants and glycosidase activities. Fermentations using pure S. cerevisiae strains were used for comparison. Yeast biomass and glycosidase activities were monitored, varietal odorants were detected using HS-SPME-GC/MS during fermentation. The final wine aroma attributes were analyzed by trained panelists. Results showed that co-inoculation with high antagonistic S. cerevisiae resulted in higher glycosidase activities than others. Pearson correlation analysis indicated that yeast biomass was positively related to glycosidase activities during fermentation. The increase in glycosidase activities was the main reason for the higher production of terpenes and C13-norisoprenoids, and for the lower C6 compound content, which lead to superior fruity and floral aromas in the final wine samples of the high antagonistic S. cerevisiae group.


Assuntos
Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/metabolismo , Pichia/metabolismo , Saccharomyces cerevisiae/metabolismo , Vinho/análise , Fermentação , Frutas/química , Sucos de Frutas e Vegetais/análise , Sucos de Frutas e Vegetais/microbiologia , Cromatografia Gasosa-Espectrometria de Massas , Norisoprenoides/análise , Norisoprenoides/metabolismo , Odorantes/análise , Pichia/enzimologia , Pichia/crescimento & desenvolvimento , Terpenos/análise , Terpenos/metabolismo
20.
J Ind Microbiol Biotechnol ; 47(6-7): 465-474, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32524454

RESUMO

ß-Alanine (ß-Ala) is an important intermediate with numerous applications in food and feed additives, pharmaceuticals, polymeric materials, and electroplating industries. Its biological production routes that employ L-aspartate-α-decarboxylase (ADC) as the key enzyme are attractive. In this study, we developed an efficient and environmentally safe method for ß-Ala production by co-expressing two different subtypes of ADC. A bacterial ADC from Bacillus subtilis (BSADC) and an insect ADC from Tribolium castaneum (TCADC) use pyruvoyl and pyridoxal-5'-phosphate (PLP) as cofactor, respectively. 3050 mM (271.5 g/L) ß-Ala was achieved from L-aspartic acid by using the whole-cell biocatalyst co-expressing BSADC and TCADC, corresponding to a conversion rate of 92.4%. Meanwhile, one-pot synthesis of ß-Ala from fumaric acid through using a tri-enzyme cascade route with two different subtypes of ADC and L-aspartase (AspA) from Escherichia coli was established. 2250 mM (200.3 g/L) ß-Ala was obtained from fumaric acid with a conversion rate of 90.0%. This work proposes a novel strategy that improves ß-Ala production in the decarboxylation pathway of L-aspartic acid.

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