Effects of tryptophan and phenylalanine on tryptophol production in Saccharomyces cerevisiae revealed by transcriptomic and metabolomic analyses

Gong Xiaowei,Luo Huajun,Hong Liu,Wu Jun,Wu Heng,Song Chunxia,Zhao Wei,Han Yi,Dao Ya,Zhang Xia,Zhu Donglai,Luo Yiyong 한국미생물학회 2022 The journal of microbiology Vol.60 No.8

Tryptophol (TOL) is a metabolic derivative of tryptophan (Trp) and shows pleiotropic effects in humans, plants and microbes. In this study, the effect of Trp and phenylalanine (Phe) on TOL production in Saccharomyces cerevisiae was determined, and a systematic interpretation of TOL accumulation was offered by transcriptomic and metabolomic analyses. Trp significantly promoted TOL production, but the output plateaued (231.02−266.31 mg/L) at Trp concentrations ≥ 0.6 g/L. In contrast, Phe reduced the stimulatory effect of Trp, which was strongly dependent on the Phe concentration. An integrated genomic, transcriptomic, and metabolomic analysis revealed that the effect of Trp and Phe on TOL production was mainly related to the transamination and decarboxylation of the Ehrlich pathway. Additionally, other genes, including thiamine regulon genes (this), the allantoin catabolic genes dal1, dal2, dal4, and the transcriptional activator gene aro80, may play important roles. These findings were partly supported by the fact that the thi4 gene was involved in TOL production, as shown by heterologous expression analysis. To the best of our knowledge, this novel biological function of thi4 in S. cerevisiae is reported here for the first time. Overall, our findings provide insights into the mechanism of TOL production, which will contribute to TOL production using metabolic engineering strategies.

Core@shell MOFs derived Co2P/CoP@NPGC as a highly-active bifunctional electrocatalyst for ORR/OER

Weijia Gong,Hongyu Zhang,Liuyang Zhou,Ya Yang,Jiashuo Wang,Heng Liang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-

In this study, Co2P/CoP hybrid nanoparticles (NPs) imbedded on the surface of core–shell metal–organicframeworks (MOFs) derived three-dimensional N, P co-doped graphitized carbon (Co2P/CoP@NPGC) areprepared via direct pyrolysis of P-containing MOF precursors. P dopant dosage is tailored to adjust activesites and crystalline phases of Co2P/CoP@NPGC. The active Co2P and CoP NPs and the synergistic effectfrom the Co-Nx/C and Co-P/C active sites and porous NPGC make the dominant contributions to theORR/OER. For ORR, the half-wave potential of Co2P/CoP@NPGC-1 is 0.93 V, which is superior to that ofPt/C (E1/2 = 0.875 V). As for OER, Co2P/CoP@NPGC-1 displays a lower overpotential (ƞ = 340 mV) comparedto RuO2 (ƞ = 380 mV, at 10 mA cm2). The Co2P@CoOOH heterojunction guarantees intrinsic conductivity. Furthermore, doping with N and P can modify the surface electronic structure of catalyst to lower theenergy of oxygen adsorption and dissociation, which are beneficial to enhance the ORR and OER activity. Additionally, its bifunctional activity parameter (DE) for ORR and OER is only 0.64 V, which is lower thanthat of Pt/C and RuO2 (0.76 V). Therefore, this work proposes a new sight into constructing a competitivecore–shell MOFs derived electrocatalyst for ORR/OER.

Association Between XPD Asp312Asn Polymorphism and Esophageal Cancer Susceptibility: A Meta-analysis

Duan, Xiao-Li,Gong, Heng,Zeng, Xian-Tao,Ni, Xiao-Bing,Yan, Yan,Chen, Wen,Liu, Guo-Lei Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

Objective: To investigate the association between xeroderma pigmentosum group D (XPD) Asp312Asn polymorphism and esophageal cancer (EC) susceptibility by meta-analysis. Methods: We searched PubMed up to April 9th, 2012, to identify relevant papers, and 8 published case-control studies including 2165 EC patients and 3141 healthy controls were yielded. Odds ratios (ORs) with relevant 95% confidence intervals (CIs) were applied to assess the association between XPD Asp312Asn polymorphism and EC susceptibility with the Comprehensive Meta-Analysis software, version 2.2. Results: Overall, the meta-analysis results suggested the XPD Asp312Asn polymorphism to be significantly associated with EC susceptibility [(Asn/Asn+Asp/Asn) vs. Asp/Asp: OR=1.20, 95%CI=1.05-1.36, p=0.01; and Asp/Asn vs. Asp/Asp: OR=1.15, 95%CI =1.01-1.31, p=0.04]. In the subgroup analysis by ethnicity and cancer type, significantly associations were found for Caucasian populations [(Asn/Asn+Asp/Asn) vs. Asp/Asp: OR=1.26, 95%CI =1.08-1.47, p<0.001; Asp/Asn vs. Asp/Asp: OR=1.19, 95%CI =1.02-1.40, p=0.03] and esophageal squamous cell carcinoma [(Asn/Asn+Asp/Asn) vs. Asp/Asp: OR=1.19, 95%CI=1.01-1.41, p=0.04]. There was no heterogeneity and no publication bias existed. Conclusions: This meta-analysis shows that the XPD Asp312Asn polymorphism may be a risk factor for developing EC, especially for Caucasian populations and esophageal squamous cell carcinoma.

Analysis of the Growth and Metabolites of a Pyruvate Dehydrogenase ComplexDeficient Klebsiella pneumoniae Mutant in a Glycerol-Based Medium

Danfeng Xu,Zongxiao Jia,Lijuan Zhang,Shuilin Fu,Heng Gong 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.5

To determine the role of pyruvate dehydrogenase complex (PDHC) in Klebsiella pneumoniae, the growth and metabolism of PDHC-deficient mutant in glycerol-based medium were analyzed and compared with those of other strains. Under aerobic conditions, the PDHC activity was fourfold higher than that of pyruvate formate lyase (PFL), and blocking of PDHC caused severe growth defect and pyruvate accumulation, indicating that the carbon flux through pyruvate to acetyl coenzyme A mainly depended on PDHC. Under anaerobic conditions, although the PDHC activity was only 50% of that of PFL, blocking of PDHC resulted in more growth defect than blocking of PFL. Subsequently, combined with the requirement of CO2 and intracellular redox status, it was presumed that the critical role of PDHC was to provide NADH for the anaerobic growth of K. pneumoniae. This presumption was confirmed in the PDHC-deficient mutant by further blocking one of the formate dehydrogenases, FdnGHI. Besides, based on our data, it can also be suggested that an improvement in the carbon flux in the PFL-deficient mutant could be an effective strategy to construct highyielding 1,3-propanediol-producing K. pneumoniae strain.

Research on Human-robot Shared Control of Throat Swab Sampling Robot Based on Intention Estimation

Ying-Long Chen,Fu-Jun Song,Peng-Yu Zhao,Yong-Jun Gong,Heng-Fei Yan 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.2

With the spread and persistence of COVID-19, pharyngeal swab sampling, is an important link in nucleic acid testing, which is characterized by a high workload and susceptibility to infection. Therefore, it is necessary for medical workers to use medical robots instead of manual site sampling for collaborative sampling. However, the traditional teleoperation has difficulty ensuring the closed-loop performance due to the delay of the actual process, along with the weak control performance; Moreover, a robot cannot accurately plan and track sampling paths due to sensor accuracy and the changes in patient pharyngeal posture. The paper proposes a human-robot shared control strategy based on intention estimation, introducing the human intention as a reference, and the operator and robot work together to solve various significant problems during sampling. The human-robot negotiation based on the method includes the human judgement and perception and the robot into the invasion task. Through, the shared control based on the operator intention estimation, the robot can operate the obstacle avoidance and approach the target contact point remotely. Finally, two kinds of experiments of invasion process of throat swab sampling are implemented: a static target invasive experiment and a dynamic target invasive experiment, aiming at two different sampling conditions. Compared with the robotic independent control sampling, the time consumption in the two experiments is reduced by 34.8% and 41.6%, respectively, and the ultimate target position is basically within the scope of sampling field (where the range of the posterior pharynx wall < 20 mm). Thus, the sampling rate can reach 100%. Compared with independent control sampling by humans, the time consumption of the two experiments is respectively reduced by 15.9% and 42.3% on average, and the target position accuracy and sampling rate are quite close. Experimental results show that the control strategy improves the speed, flexibility, and intelligence of task execution compared to common sampling methods, laying the foundation for low-cost human-robot collaborative sampling.