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1.
J Phys Condens Matter ; 36(28)2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38574677

ABSTRACT

Our study delved into the detailed investigation of Cs2SnBr6double perovskites, focusing on their electrical properties, lattice dynamics, and stability. The direct bandgap for Cs2SnBr6was estimated to be at 2.93 eV. One external translational mode of the Cs+lattice withT2gsymmetry and three internal modes of the octahedral withA1g,Eg, andT2gsymmetries are defined by calculated lattice dynamics, experimental micro-Raman scattering. We show a correlation with first-principles calculations, validating using a band-structured electronic approach to understanding the behavior of charge carriers, and electron-phonon interactions in Cs2SnBr6. We propose that electron-vibration interactions result in self-trapped excitons (STEs) displaying significant Stokes shifts (0.508 eV) and broad-spectrum emission. Understanding the behavior of STEs is fundamental for their optoelectronic applications.

3.
BMC Oral Health ; 24(1): 230, 2024 Feb 13.
Article in English | MEDLINE | ID: mdl-38350906

ABSTRACT

BACKGROUND: The present study aimed to evaluate the effectiveness of using platelet-rich fibrin (PRF) as the apical matrix for the placement of MTA in nonsurgical endodontic therapy for teeth with periapical lesions and open apices. METHODS: Twelve teeth from eleven patients with periapical periodontitis and open apices were enrolled in the study. Nonsurgical endodontic therapy was performed with the PRF used as an apical barrier and the MTA manipulated as an apical plug for further thermoplasticized gutta percha in the remaining part of the root canal. Clinical signs and periapical digital radiographs were recorded and analyzed to evaluate the curing progress after periodical follow-ups of 1, 3, and 6 months. The horizontal dimension of the periapical lesion was determined, and the changes in the dimensions were recorded each time. The Friedman test was used for statistical analysis, with P < .05 serving as the threshold for determining statistical significance. RESULTS: All patients had no clinical symptoms after the first month of treatment, with a significant reduction in the periapical lesion after periodical appointments. CONCLUSIONS: PRF is an effective barrier when combined with MTA for the treatment of teeth with periapical periodontitis and open apices.


Subject(s)
Periapical Periodontitis , Platelet-Rich Fibrin , Root Canal Filling Materials , Humans , Calcium Compounds/therapeutic use , Root Canal Filling Materials/therapeutic use , Gutta-Percha/therapeutic use , Periapical Periodontitis/therapy , Periapical Periodontitis/pathology , Drug Combinations , Tooth Apex/diagnostic imaging , Tooth Apex/pathology , Oxides/therapeutic use , Silicates/therapeutic use
4.
J Am Heart Assoc ; 13(2): e030995, 2024 Jan 16.
Article in English | MEDLINE | ID: mdl-38214252

ABSTRACT

BACKGROUND: Studies have reported the strength of cardiovascular health (CVH) metrics in parent-offspring relationships. This study aimed to describe the sex-specific associations between CVH in parents and adult offspring. METHODS AND RESULTS: This study was conducted on the Korea National Health and Nutrition Examination Survey data set, which analyzed trios of mother-father-child, with the child's age from 20 to 39 years. To use the nature of sampling design, survey weighting was applied to all our analyses. Ideal CVH was defined as a cluster of at least 5 ideal individual CVH metrics. We examined the association between parents and their adult offspring regarding clustering CVH and individual CVH metrics through odds ratios and 95% CIs using multiple logistic regression with standard errors adjusted for within-family clustering. The study included 1267 married couples comprising 748 sons and 819 daughters. After adjusting for household income and offspring's sex, age, education, and alcohol consumption, an offspring with either parent attaining a nonideal CVH was 3.52 times more likely to have nonideal CVH. Fathers' nonideal CVH was significantly positively associated with the daughters' nonideal CVH. Maternal nonideal CVH was significantly positively associated with the son's nonideal CVH. When analyzing individual CVH metrics, ideal status in fathers or mothers reduced the likelihood of their offspring having a nonideal status. CONCLUSIONS: This cross-sectional study showed positive and differential associations of CVH and its components between parents' and offsprings' nonideal status. Our hypothesis-generating results suggest the relevance of using CVH as a composite indicator in family-centered approaches and heart-health interventions.


Subject(s)
Cardiovascular Diseases , Quality Indicators, Health Care , Adult , Male , Female , Humans , Young Adult , Nutrition Surveys , Cross-Sectional Studies , Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/epidemiology , Parents , Republic of Korea/epidemiology , Health Status , Risk Factors
5.
Microb Cell Fact ; 22(1): 153, 2023 Aug 13.
Article in English | MEDLINE | ID: mdl-37574555

ABSTRACT

BACKGROUND: The omnipresence of population heterogeneity in industrial bioprocesses originates from prevailing dynamic bioprocess conditions, which promote differences in the expression of cellular characteristics. Despite the awareness, the concrete consequences of this phenomenon remain poorly understood. RESULTS: Therefore, for the first time, a L-phenylalanine overproducing Escherichia coli quadruple reporter strain was established for monitoring of general stress response, growth behavior, oxygen limitation and product formation of single cells based on mTagBFP2, mEmerald, CyOFP1, and mCardinal2 expression measured by flow cytometry. This strain was applied for the fed-batch production of L-phenylalanine from glycerol and ammonia in a stirred-tank bioreactor at homogeneous conditions compared to the same process in a novel two-compartment bioreactor. This two-compartment bioreactor consists of a stirred-tank bioreactor with an initial volume of 0.9 L (homogeneous zone) with a coiled flow inverter with a fixed working volume of 0.45 L as a bypass (limitation zone) operated at a mean hydraulic residence time of 102 s. The product formation was similar in both bioreactor setups with maximum L-phenylalanine concentrations of 21.1 ± 0.6 g L-1 demonstrating the consistency of this study's microbial L-phenylalanine production. However, cell growth was vulnerable to repetitive exposure to the dynamically changing conditions in the two-compartment bioreactor with maximum biomass yields reduced by 21%. The functionality of reporter molecules was approved in the stirred-tank bioreactor cultivation, in which expressed fluorescence levels of all four markers were in accordance with respective process state variables. Additional evaluation of the distributions on single-cell level revealed the presence of population heterogeneity in both bioprocesses. Especially for the marker of the general stress response and the product formation, the corresponding histograms were characterized by bimodal shapes and broad distributions. These phenomena were pronounced particularly at the beginning and the end of the fed-batch process. CONCLUSIONS: The here shown findings confirm multiple reporter strains to be a noninvasive tool for monitoring cellular characteristics and identifying potential subpopulations in bioprocesses. In combination with experiments in scale-down setups, these can be utilized for a better physiological understanding of bioprocesses and support future scale-up procedures.


Subject(s)
Bioreactors , Escherichia coli , Escherichia coli/metabolism , Fermentation , Biomass , Oxygen/metabolism
6.
Microorganisms ; 11(7)2023 Jul 06.
Article in English | MEDLINE | ID: mdl-37512936

ABSTRACT

When targeting robust, high-yielding bioprocesses, phenomena such as population heterogeneity have to be considered. Therefore, the influence of the conditions which the cells experience prior to the main culture should also be evaluated. Here, the influence of a pre-culture medium (complex vs. minimal medium), optical density for inoculation of the main culture (0.005, 0.02 and 0.0125) and harvest time points of the pre-culture in exponential growth phase (early, mid and late) on the level of population heterogeneity in batch cultures of the Escherichia coli triple reporter strain G7BL21(DE3) in stirred-tank bioreactors was studied. This strain allows monitoring the growth (rrnB-EmGFP), general stress response (rpoS-mStrawberry) and oxygen limitation (nar-TagRFP657) of single cells through the expression of fluorescent proteins. Data from batch cultivations with varying pre-culture conditions were analysed with principal component analysis. According to fluorescence data, the pre-culture medium had the largest impact on population heterogeneities during the bioprocess. While a minimal medium as a pre-culture medium elevated the differences in cellular growth behaviour in the subsequent batch process, a complex medium increased the general stress response and led to a higher population heterogeneity. The latter was promoted by an early harvest of the cells with low inoculation density. Seemingly, nar-operon expression acted independently of the pre-culture conditions.

7.
Heliyon ; 9(7): e17663, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37456030

ABSTRACT

This study aimed to produce bacterial cellulose from paper waste sludge (PWS) as a method of utilizing the cellulose source from the remaining pulp in the material. Initially, PWS was hydrolyzed by sulfuric acid to create an enriched-reducing sugar hydrolysate. One-factor experiments were conducted with a fixed amount of PWS (5 g) to investigate the influence of hydrolysis conditions, including water, sulfuric acid addition, temperature, and retention time, on the production yield of reducing sugars. Based on these results, the Box-Behnken model was designed to optimize the hydrolysis reaction. The optimal hydrolysis conditions were 10 ml/g of the sulfuric acid solution (30.9%) at 105.5 °C for 90 min of retention time 0.81 (gGE/g PWS), corresponding to a conversion yield of 40.5%). Subsequently, 100 ml of the filtered and neutralized PWS hydrolysate was used as the culture to produce the bacterial cellulose (BC) using Acetobacter xylinum, which produced 12 g/L of bacterial cellulose. The conversion yield of bacterial cellulose calculated as the ratio of the weight of produced bacterial cellulose to that of cellulose in PWS reached 33.3%. The structure of the obtained BC was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) to indicate the formation of nano-cellulose fiber networks. This research proposed a combined method to convert paper waste sludge into bacterial cellulose, demonstrating the potential for waste utilization and sustainable production of paper industries for added-value products.

8.
Eng Life Sci ; 23(1): e2100162, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36619877

ABSTRACT

Biotechnological production processes are sustainable approaches for the production of biobased components such as amino acids for food and feed industry. Scale-up from ideal lab-scale bioreactors to large-scale processes is often accompanied by loss in productivity. This may be related to population heterogeneities of cells originating from isogenic cultures that arise due to dynamic non-ideal conditions in the bioreactor. To better understand this phenomenon, deeper insights into single-cell physiologies in bioprocesses are mandatory before scale-up. Here, a triple reporter strain (3RP) was developed by chromosomally integrating the fluorescent proteins mEmerald, CyOFP1, and mTagBFP2 into the L-phenylalanine producing Escherichia coli strain FUS4 (pF81kan) to allow monitoring of growth, oxygen availability, and general stress response of the single cells. Functionality of the 3RP was confirmed in well-mixed lab-scale fed-batch processes with glycerol as carbon source in comparison to the strain without fluorescent proteins, leading to no difference in process performance. Fluorescence levels could successfully reflect the course of related process state variables, revealed population heterogeneities during the transition between different process phases and potentially subpopulations that exhibit superior process performance. Furthermore, indications were found for noise in gene expression as regulation strategy against environmental perturbation.

9.
J Am Chem Soc ; 145(6): 3443-3453, 2023 02 15.
Article in English | MEDLINE | ID: mdl-36689349

ABSTRACT

The generation of enantiodivergent biocatalysts for C-H oxyfunctionalizations is ever more important in modern synthetic chemistry. Here, we have applied the FuncLib algorithm based on phylogenetic and Rosetta calculations to design a diverse repertoire of active, stable, and enantiodivergent fungal peroxygenases. 24 designs, each carrying 4-5 mutations in the catalytic core, were expressed functionally in yeast and benchmarked against characteristic model compounds. Several designs were active and stable in a range of temperature and pH, displaying unprecedented enantiodivergence, changing regioselectivity from alkyl to aromatic hydroxylation, and increasing catalytic efficiencies up to 10-fold, with 15-fold improvements in total turnover numbers over the parental enzyme. We find that this dramatic functional divergence stems from beneficial epistasis among the mutations and an extensive reorganization of the heme channel. Our work demonstrates that FuncLib can rapidly design highly functional libraries enriched in enantioselective peroxygenases not seen in nature for a range of biotechnological applications.


Subject(s)
Mixed Function Oxygenases , Saccharomyces cerevisiae , Phylogeny , Mixed Function Oxygenases/chemistry , Catalysis , Catalytic Domain , Saccharomyces cerevisiae/metabolism
10.
Clin Hypertens ; 28(1): 41, 2022 Dec 15.
Article in English | MEDLINE | ID: mdl-36517881

ABSTRACT

BACKGROUNDS: We aimed to investigate whether a spouse's cardiovascular health (CVH) metrics status affects the other spouse's ideal CVH using a Korea nationwide representative survey. METHODS: We used the health data of 6,030 married couples who participated in the Korea National Health and Nutrition Examination Survey from 2014 to 2019. The CVH was defined using seven metrics: smoking status, blood pressure, body mass index, total cholesterol, fasting blood glucose, physical activity, and diet, following the American Heart Association guidelines and modifications for body mass index cutoffs and diet quality. The CVH score was calculated on a scale ranging from 0 to 7, with the ideal CVH defined as attaining ideal scores in at least five CVH metrics. Multiple logistic regression analyses were used to assess whether husband's ideal CVH was associated with his wife's odds for having ideal CVH, and vice versa. RESULTS: The mean CVH scores were 3.2 and 4.0 for husband and wife, respectively. After fully adjusting for age and education of both partners and household income, husbands had 1.49 times (95% confidence interval [CI], 1.27-1.69) higher odds of achieving ideal CVH if their wives had also achieved ideal CVH. Meanwhile, wives whose husbands achieved ideal CVH also had 1.46 times (95% CI, 1.27-1.69) higher odds of achieving ideal CVH. Nonsmoking (57.17%), ideal fasting blood glucose level (34.93%), and ideal diet intake (24.18%) were the most concordant CVH metrics among spouses. CONCLUSIONS: Our study found a significant spousal concordance of ideal CVH in Korean married couples. This finding supports the use of a couple-based interventional strategy targeted to promote CVH.

11.
Micromachines (Basel) ; 13(12)2022 Nov 29.
Article in English | MEDLINE | ID: mdl-36557410

ABSTRACT

This paper presents a novel tattooing capsule endoscope (TCE) for delivering a certain amount of ink to the submucosal layer of digestive tract organs. A dual-function permanent magnet is used for locomotion and injection activation. The developed capsule endoscope can move actively in 5 DOF due to the interaction between the permanent magnet and a controllable external magnetic field produced by an electromagnet actuation system. In addition, the permanent magnet is involved in a specially designed mechanism to activate a process that creates a squeezing motion to eject the liquid from the storage room to the target. The dimension of the prototype is 12.5 mm in diameter and 34.6 mm in length. The proposed TCE is tested ex vivo using a fresh porcine small-intestine segment. We were able to direct the TCE to the target and deliver the tattoo agent into the tissue. The proposed mechanism can be used for drug delivery or lesion tattooing, as well as to accelerate the realization of the functional capsule endoscope in practice.

12.
Pharmaceutics ; 14(11)2022 Nov 06.
Article in English | MEDLINE | ID: mdl-36365211

ABSTRACT

The use of untethered microrobots for precise synergistic anticancer drug delivery and controlled release has attracted attention over the past decade. A high surface area of the microrobot is desirable to achieve greater therapeutic effect by increasing the drug load. Therefore, various nano- or microporous microrobot structures have been developed to load more drugs. However, as most porous structures are not interconnected deep inside, the drug-loading efficiency may be reduced. Here, we propose a magnetically guided helical microrobot with a Gyroid surface for high drug-loading efficiency and precise drug delivery. All spaces inside the proposed microrobot are interconnected, thereby enabling drug loading deep inside the structure. Moreover, we introduce gold nanostars on the microrobot structure for near-infrared-induced photothermal therapy and triggering drug release. The results of this study encourage further exploration of a high loading efficiency in cell-based therapeutics, such as stem cells or immune cells, for microrobot-based drug-delivery systems.

13.
Glob Health Sci Pract ; 10(2)2022 04 28.
Article in English | MEDLINE | ID: mdl-35487560

ABSTRACT

INTRODUCTION: In 2017, aligned with global World Health Organization tetanus guidelines, Vietnam prepared evidence to support a recommendation to introduce the tetanus-diphtheria (Td) vaccine into routine immunization. This study aimed to provide evidence on the costs and budgetary impact of the potential replacement of the tetanus-toxoid (TT) vaccine with the Td vaccine, considering different possible delivery strategies. METHOD: We used an activity-based ingredients costing approach to estimate the 2017 program costs of providing TT vaccination to girls aged 15-16 years and conducting Td campaigns in outbreak areas. We performed a budget impact analysis for 2018-2025 using the cost per dose estimates based on the current delivery of these vaccines. We assumed complete cessation of TT vaccination of girls aged 15-16 years and a transition period where Td outbreak control campaigns would still occur. Td vaccine was assumed to be provided to children aged 7 years using either facility- or school-based delivery or combined facility- and school-based delivery. RESULTS: The delivery cost per dose for current TT vaccination for girls aged 15-16 years was US$1.49 for school-based delivery, US$1.76 for facility-based delivery, and US$3.86 for delivery via outreach. Td vaccination through campaigns was estimated to cost US$3.56/dose. During 2018-2025, replacing the TT vaccine for girls aged 15-16 years with the Td vaccine for children aged 7 years is estimated to save US$4.61 million in immunization delivery costs if a school-based delivery strategy is used or US$1.04 million if facility-based delivery is used. CONCLUSION: Compared to the current plan, delivery of Td routine vaccination via a school-based strategy was the most cost saving. These results were used in late 2019 to support the delivery of Td vaccination using a school-based delivery strategy for children aged 7 years in 30 Northern provinces in Vietnam.


Subject(s)
Diphtheria , Tetanus , Child , Diphtheria/epidemiology , Diphtheria/prevention & control , Diphtheria-Tetanus Vaccine , Female , Humans , Tetanus/epidemiology , Tetanus/prevention & control , Tetanus Toxoid , Vaccination , Vietnam
14.
Eng Life Sci ; 22(3-4): 260-278, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35382548

ABSTRACT

Flow cytometry and its technological possibilities have greatly advanced in the past decade as analysis tool for single cell properties and population distributions of different cell types in bioreactors. Along the way, some solutions for automated real-time flow cytometry (ART-FCM) were developed for monitoring of bioreactor processes without operator interference over extended periods with variable sampling frequency. However, there is still great potential for ART-FCM to evolve and possibly become a standard application in bioprocess monitoring and process control. This review first addresses different components of an ART-FCM, including the sampling device, the sample-processing unit, the unit for sample delivery to the flow cytometer and the settings for measurement of pre-processed samples. Also, available algorithms are presented for automated data analysis of multi-parameter fluorescence datasets derived from ART-FCM experiments. Furthermore, challenges are discussed for integration of fluorescence-activated cell sorting into an ART-FCM setup for isolation and separation of interesting subpopulations that can be further characterized by for instance omics-methods. As the application of ART-FCM is especially of interest for bioreactor process monitoring, including investigation of population heterogeneity and automated process control, a summary of already existing setups for these purposes is given. Additionally, the general future potential of ART-FCM is addressed.

15.
Front Mol Biosci ; 9: 806213, 2022.
Article in English | MEDLINE | ID: mdl-35350716

ABSTRACT

Mathematical modeling is a promising tool for better understanding of cellular processes. In recent years, the development of coarse-grained models has gained attraction since these simple models are able to capture and describe a broad range of growth conditions. Coarse-grained models often comprise only two cellular components, a low molecular component as representative for central metabolism and energy generation and a macromolecular component, representing the entire proteome. A framework is presented that presents a strict mass conservative model for bacterial growth during a biotechnological production process. After providing interesting properties for the steady-state solution, applications are presented 1) for a production process of an amino acid and 2) production of a metabolite from central metabolism.

16.
Epidemiol Health ; 44: e2022013, 2022.
Article in English | MEDLINE | ID: mdl-35008144

ABSTRACT

OBJECTIVES: This study examined socioeconomic inequalities in compliance with precautions and health behavior changes during the coronavirus disease 2019 (COVID-19) outbreak using a representative Korean sample. METHODS: This exploratory study utilized around 210,000 participants aged ≥25 years in the Korean Community Health Survey 2020. Socioeconomic status was measured with educational attainment and household income. Outcomes included non-compliance with 8 precaution measures and deterioration in 6 health behaviors. The relative inequality index (RII) was calculated to quantify the degree of inequality by education and income level. RII values >1.0 indicate that deprived people have a higher frequency of health problems, and RII values <1.0 conversely indicate a higher frequency of health problems in more advantaged groups. RESULTS: People with lower education or income levels tended to have higher rates of non-compliance with COVID-19 safety precautions (RII range, 1.20 to 3.05). Lower education and income levels were associated with an increased smoking amount (RII=2.10 and 1.67, respectively) and sleep duration changes (RII=1.21 and 1.36, respectively). On the contrary, higher education and income levels were associated with decreased physical activity (RII=0.59 and 0.77, respectively) and increased delivery food consumption (RII=0.27 and 0.37, respectively). However, increased alcohol drinking was associated with lower education and income levels in younger men (RII=1.73 and 1.31, respectively), but with higher levels in younger women (RII=0.73 and 0.68, respectively). CONCLUSIONS: Our findings suggest the need to develop customized strategies, considering the characteristics of the target population, to decrease the burden and impact of the COVID-19 outbreak.


Subject(s)
COVID-19 , Adult , Disease Outbreaks/prevention & control , Female , Health Behavior , Health Status Disparities , Humans , Income , Male , Public Health , Republic of Korea/epidemiology , SARS-CoV-2 , Socioeconomic Factors
17.
Epidemiology and Health ; : e2022013-2022.
Article in Korean | WPRIM (Western Pacific) | ID: wpr-937569

ABSTRACT

OBJECTIVES@#This study examined socioeconomic inequalities in compliance with precautions and health behavior changes during the coronavirus disease 2019 (COVID-19) outbreak using a representative Korean sample. @*METHODS@#This exploratory study utilized around 210,000 participants aged ≥25 years in the Korean Community Health Survey 2020. Socioeconomic status was measured with educational attainment and household income. Outcomes included non-compliance with 8 precaution measures and deterioration in 6 health behaviors. The relative inequality index (RII) was calculated to quantify the degree of inequality by education and income level. RII values >1.0 indicate that deprived people have a higher frequency of health problems, and RII values <1.0 conversely indicate a higher frequency of health problems in more advantaged groups. @*RESULTS@#People with lower education or income levels tended to have higher rates of non-compliance with COVID-19 safety precautions (RII range, 1.20 to 3.05). Lower education and income levels were associated with an increased smoking amount (RII=2.10 and 1.67, respectively) and sleep duration changes (RII=1.21 and 1.36, respectively). On the contrary, higher education and income levels were associated with decreased physical activity (RII=0.59 and 0.77, respectively) and increased delivery food consumption (RII=0.27 and 0.37, respectively). However, increased alcohol drinking was associated with lower education and income levels in younger men (RII=1.73 and 1.31, respectively), but with higher levels in younger women (RII=0.73 and 0.68, respectively). @*CONCLUSIONS@#Our findings suggest the need to develop customized strategies, considering the characteristics of the target population, to decrease the burden and impact of the COVID-19 outbreak.

18.
Diagnostics (Basel) ; 11(10)2021 Oct 12.
Article in English | MEDLINE | ID: mdl-34679575

ABSTRACT

This paper presents an active locomotion capsule endoscope system with 5D position sensing and real-time automated polyp detection for small-bowel and colon applications. An electromagnetic actuation system (EMA) consisting of stationary electromagnets is utilized to remotely control a magnetic capsule endoscope with multi-degree-of-freedom locomotion. For position sensing, an electronic system using a magnetic sensor array is built to track the position and orientation of the magnetic capsule during movement. The system is integrated with a deep learning model, named YOLOv3, which can automatically identify colorectal polyps in real-time with an average precision of 85%. The feasibility of the proposed method concerning active locomotion and localization is validated and demonstrated through in vitro experiments in a phantom duodenum. This study provides a high-potential solution for automatic diagnostics of the bowel and colon using an active locomotion capsule endoscope, which can be applied for a clinical site in the future.

19.
Appl Environ Microbiol ; 87(19): e0087821, 2021 09 10.
Article in English | MEDLINE | ID: mdl-34288703

ABSTRACT

Fungal unspecific peroxygenases (UPOs) are emergent biocatalysts that perform highly selective C-H oxyfunctionalizations of organic compounds, yet their heterologous production at high levels is required for their practical use in synthetic chemistry. Here, we achieved functional expression of two new unusual acidic peroxygenases from Candolleomyces (Psathyrella) aberdarensis (PabUPO) in yeasts and their production at a large scale in a bioreactor. Our strategy was based on adopting secretion mutations from an Agrocybe aegerita UPO mutant, the PaDa-I variant, designed by directed evolution for functional expression in yeast, which belongs to the same phylogenetic family as PabUPOs, long-type UPOs, and shares 65% sequence identity. After replacing the native signal peptides with the evolved leader sequence from PaDa-I, we constructed and screened site-directed recombination mutant libraries, yielding two recombinant PabUPOs with expression levels of 5.4 and 14.1 mg/liter in Saccharomyces cerevisiae. These variants were subsequently transferred to Pichia pastoris for overproduction in a fed-batch bioreactor, boosting expression levels up to 290 mg/liter, with the highest volumetric activity achieved to date for a recombinant peroxygenase (60,000 U/liter, with veratryl alcohol as the substrate). With a broad pH activity profile, ranging from pH 2.0 to 9.0, these highly secreted, active, and stable peroxygenases are promising tools for future engineering endeavors as well as for their direct application in different industrial and environmental settings. IMPORTANCE In this work, we incorporated several secretion mutations from an evolved fungal peroxygenase to enhance the production of active and stable forms of two unusual acidic peroxygenases. The tandem-yeast expression system based on S. cerevisiae for directed evolution and P. pastoris for overproduction on an ∼300-mg/liter scale is a versatile tool to generate UPO variants. By employing this approach, we foresee that acidic UPO variants will be more readily engineered in the near future and adapted to practical enzyme cascade reactions that can be performed over a broad pH range to oxyfunctionalize a variety of organic compounds.


Subject(s)
Agaricales/enzymology , Agaricales/genetics , Mixed Function Oxygenases/genetics , Bioreactors , Fermentation , Mutation , Pichia/genetics , Protein Engineering , Saccharomyces cerevisiae/genetics
20.
Sci Rep ; 11(1): 15122, 2021 07 23.
Article in English | MEDLINE | ID: mdl-34302003

ABSTRACT

Magnetic nanorobots (MNRs) based on paramagnetic nanoparticles/nanoclusters for the targeted therapeutics of anticancer drugs have been highlighted for their efficiency potential. Controlling the locomotion of the MNRs is a key challenge for effective delivery to the target legions. Here, we present a method for controlling paramagnetic nanoclusters through enhanced tumbling and disaggregation motions with a combination of rotating field and gradient field generated by external electromagnets. The mechanism is carried out via an electromagnetic actuation system capable of generating MNR motions with five degrees of freedom in a spherical workspace without singularity. The nanocluster swarm structures can successfully pass through channels to the target region where they can disaggregate. The results show significantly faster response and higher targeting rate by using rotating magnetic and gradient fields. The mean velocities of the enhanced tumbling motion are twice those of the conventional tumbling motion and approximately 130% higher than the gradient pulling motion. The effects of each fundamental factor on the locomotion are investigated for further MNR applications. The locomotion speed of the MNR could be predicted by the proposed mathematical model and agrees well with experimental results. The high access rate and disaggregation performance insights the potentials for targeted drug delivery application.

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