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1.
Anal Chem ; 96(21): 8576-8585, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38712678

ABSTRACT

Quinolones, a widely used class of antibiotics, present significant environmental and health concerns if they excessively remain in the environment and in food. Aptamers specific to quinolones can be applied as bioreceptors for the detection of quinolone residues in the environment and food. The quinolone family contains dozens of different individuals that share the same core structure coupled with various substituents at six different positions. The diversity and complexity of the substitution sites make it a challenge to choose a set of representative molecules that encompass all the desired sites and preserve the core molecular framework for the screening of quinolone-specific aptamers via systematic evolution of ligands by exponential enrichment (SELEX). To address this challenge, we introduce a novel parallel-series strategy guided by Liebig's law for isolating quinolone-specific cross-reactive aptamers by using the library-immobilized SELEX method. Through this approach, we successfully identified 5 aptamers (Apt.AQ01-Apt.AQ05) with high binding affinity and excellent specificity to 24 different quinolone individuals. Among them, Apt.AQ03 showcased optimal performance with affinities ranging from 0.14 to 1.07 µM across the comprehensive set of 24 quinolones, exhibiting excellent specificity against nontarget interferents. The binding performance of Apt.AQ03 was further characterized with microscale thermophoresis, circular dichroism spectra, and an exonuclease digestion assay. By using Apt.AQ03 as a bioreceptor, a fluorescence resonance energy transfer (FRET) aptasensor was developed for the detection of 24 quinolones in milk, achieving a remarkable detection limit of 14.5-21.8 ng/mL. This work not only establishes a robust and effective strategy for selecting cross-reactive aptamers applicable to other small-molecule families but also provides high-quality aptamers for developing various high-throughput and reliable methods for the detection of multiple quinolone residues in food.


Subject(s)
Aptamers, Nucleotide , Quinolones , SELEX Aptamer Technique , Aptamers, Nucleotide/chemistry , Quinolones/analysis , Quinolones/chemistry , SELEX Aptamer Technique/methods , Animals , Milk/chemistry
2.
Bioresour Technol ; 397: 130497, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38408501

ABSTRACT

To effectively improve biomass growth and flue-gas CO2 fixation of microalgae, acid-tolerant Euglena gracilis was modified with cobalt-60 γ-ray irradiation and polyethylene glycol (PEG) adaptive screening to obtain the mutant strain M800. The biomass dry weight and maximum CO2 fixation rate of M800 were both 1.47 times higher than that of wild strain, which was attributed to a substantial increase in key carbon fixation enzyme RuBisCO activity and photosynthetic pigment content. The high charge separation quantum efficiency in PSII reaction center, efficient light utilization and energy regulation that favors light conversion, were the underlying drivers of efficient photosynthetic carbon fixation in M800. M800 had stronger antioxidant capacity in sufficient high-carbon environment, alleviating lipid peroxidation damage. After adding 1 mM PEG, biomass dry weight of M800 reached 2.31 g/L, which was 79.1 % higher than that of wild strain. Cell proliferation of M800 was promoted, the apoptosis and necrosis rates decreased.


Subject(s)
Euglena gracilis , Microalgae , Carbon Dioxide , Photosynthesis , Mutagenesis , Carbon Cycle , Biomass
3.
Int J Biol Macromol ; 258(Pt 2): 128962, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38145691

ABSTRACT

Platelet-rich plasma (PRP) contains a variety of growth factors (GFs) and has been used in the treatment of a variety of diseases, including skin lesions. In particular, PRP with low immunogenicity will be more widely used. However, the explosive release of GFs limits its further application. In order to achieve controlled release of GFs, a multifunctional and reactive oxygen species (ROS)/pH dual responsive hydrogel was developed to load PRP derived from human cord blood for the treatment of skin wound healing. Based on the hydrogen bond and Schiff base interaction, carboxymethyl chitosan (CMCS), oxidized dextran (Odex) and oligomeric procyanidins (OPC) were crosslinked to form CMCS/Odex/OPC/PRP hydrogel with good injectability, self-healing, adhesion, ROS scavenging, antibacterial activity, controlled and sustained release of GFs. In vitro cell experiments suggested that this hydrogel possessed excellent biocompatibility and could promote the proliferation and migration of L929. In vivo healing of full-layer skin wounds further indicated that the prepared hydrogel could regulate inflammation and promote epithelialization, collagen deposition, and angiogenesis. In summary, this present study demonstrates that CMCS/Odex/OPC/PRP hydrogel may serve as a promising multifunctional dressing for skin wound healing.


Subject(s)
Chitosan , Platelet-Rich Plasma , Humans , Hydrogels/chemistry , Chitosan/chemistry , Delayed-Action Preparations , Reactive Oxygen Species , Wound Healing , Anti-Bacterial Agents/analysis , Intercellular Signaling Peptides and Proteins , Platelet-Rich Plasma/chemistry , Hydrogen-Ion Concentration
4.
Bioresour Technol ; 386: 129533, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37479043

ABSTRACT

Catalysts with hierarchical porous structures and increased active defects play a crucial role in catalyzing the conversion of microalgae lipids. However, the template methods used for pore expansion and the acidification process employed to enhance activity are cumbersome and prone to deactivation. It is necessary to propose a simple and versatile synthetic approach to overcome these challenges. By modulating N,N-dimethylformamide basicity with formic acid, MOF-808 exhibited enhanced coordination of benzene-1,3,5-tricarboxylic acid to Zr-clusters, creating three types of functional defects. These defects increased pore size from 1.63 nm to 5.34 nm and enhanced catalyst acidity by 22.8%, while maintaining high porosity. The active catalytic sites were confirmed to be defect sites (exposed Zr4+) through density functional theory. Compared to regular MOF-808, catalyst MOF-808-3/1 shows enhanced hierarchical porosity and increased acidity, enabling efficient conversions at reduced reaction temperature (100 °C) and pressure (352 kPa) compared to 200 °C and 4036 kPa, respectively.


Subject(s)
Metal-Organic Frameworks , Microalgae , Biofuels , Ligands , Temperature , Lipids
5.
Sci Total Environ ; 868: 161629, 2023 Apr 10.
Article in English | MEDLINE | ID: mdl-36657669

ABSTRACT

In order to improve CO2 biofixation efficiency of microalgae cultivated with coal-chemical flue gas, CO2 gradient domestication was employed to improve high-concentration CO2 tolerance and photoautotrophic growth of acid-tolerant Euglena gracilis. The dried biomass yield of photoautotrophic growth of E.gracilis increased from 1.09 g/L (wild-type strain) by 21 % to 1.32 g/L with CO2 gradient domestication to 15 % CO2. The RuBisCO activity and biomass production of E.gracilis strain domesticated to 99 % CO2 were 2.63 and 3.4 times higher, respectively, than those of wild-type strain. The chlorophyll a and b contents were 2.52 and 1.79 times higher, respectively, than those of wild-type strain. Superoxide dismutase and catalase activities of 99 % CO2-domesticated strain increased to 1.24 and 6 times, which reduced peroxide damage under high carbon stress and resulted in lower apoptotic and necrotic rates of domesticated strain. Thus, this work provides valuable guidance for CO2 fixation and adaptive evolution of E. gracilis in industrial flue gas.


Subject(s)
Euglena gracilis , Microalgae , Carbon Dioxide/chemistry , Domestication , Chlorophyll A , Biomass
6.
J Environ Manage ; 331: 117285, 2023 Apr 01.
Article in English | MEDLINE | ID: mdl-36642047

ABSTRACT

Oil-based drill cuttings (OBDCs) are hazardous wastes associated with the process of oil and gas extraction. In this paper, OBDCs were treated using a self-designed plasma vitrification system. The basic physicochemical properties of the OBDCs were analyzed, followed by a plasma vitrification mechanism investigation of the OBDCs. The environmental pollution risk of the vitreous slags obtained from thermal plasma treatment was also evaluated with the heavy metal extraction toxicity procedure. The batch of vitreous slags with an average glass phase content of 98.60% had a dense and smooth surface and an oxygen-to-silicon (O/Si) ratio ranging from 3.68 to 4.32, according to the findings. The melting temperature and treatment duration have a great effect on the loss ratio on acid dissolution. The leaching concentrations of Pb and Zn were 0.0004 mg/L and 0.068 mg/L, respectively, consistent with the chlorination reaction promoted by thermal plasma. Fourier transform infrared spectroscopy analysis showed that there was no organic matter in the vitreous slag, achieving the goal of harmless transition. The specific energy consumption of vitreous slags was predicted and verified by response surface methodology (RSM). This study describes the vitrification process and harmless treatment of OBDCs by thermal plasma technology, and vitreous slags have great potential for resource utilization.


Subject(s)
Metals, Heavy , Plasma Gases , Plasma Gases/analysis , Vitrification , Environmental Pollution/analysis , Metals, Heavy/chemistry , Temperature
7.
Protoplasma ; 260(3): 885-897, 2023 May.
Article in English | MEDLINE | ID: mdl-36416933

ABSTRACT

To clarify dynamic changes of organelle microstructures in Chlorella pyrenoidosa cells during photosynthetic growth with CO2 fixation, three-dimensional (3D) organelle microstructures in three growth periods of meristem, elongation, and maturity were quantitatively determined and comprehensively reconstructed with focused ion beam scanning electron microscopy (FIB-SEM). The single round-pancake mitochondria in each cell split into a dumbbell and then into a circular ring, while the barycenter distance of mitochondria to chloroplast and nucleus was reduced to 45.5% and 88.3% to strengthen energy transfer, respectively. The single pyrenoid consisting of a large part and another small part in each chloroplast gradually developed to a mature state in which the two parts were nearly equal in size. The nucleolus progressively became larger with euchromatin replication. The number of starch grains gradually increased, but the mean grain volume remained nearly unchanged.


Subject(s)
Chlorella , Microscopy, Electron, Scanning , Imaging, Three-Dimensional/methods , Mitochondria , Cell Nucleus
8.
Medicine (Baltimore) ; 102(52): e36743, 2023 Dec 29.
Article in English | MEDLINE | ID: mdl-38206748

ABSTRACT

RATIONALE: In recent times, the pervasive adoption of the action research method has garnered substantial attention both domestically and internationally. Its integration has traversed various domains of nursing research, nursing education, and nursing practice, yielding commendable outcomes. However, a notable gap persists, as this method remains untapped in the realm of nursing care concerning the prevention of postoperative lymphedema in breast cancer patients. DIAGNOSIS: To employ the action research methodology in the context of patients undergoing axillary lymph node dissection surgery for breast cancer, aiming to investigate its impact on mitigating postoperative lymphedema and assessing its influence on the patient's quality of life, as well as levels of anxiety and depression postoperatively. INTERVENTION: The study focused on breast cancer patients admitted to our hospital from January 2022 to December 2022. Among them, 44 patients from January to June constituted the control group, while 44 patients from July to December comprised the observation group. Conventional nursing measures were applied to the control group, whereas the observation group received nursing interventions rooted in the action research method. A comparative analysis was conducted between the 2 groups, assessing the incidence of postoperative lymphedema, daily life ability, as well as levels of anxiety and depression. OUTCOMES: The prevalence of edema was notably reduced in the observation group (20.93%) compared to the control group (42.22%), with a statistically significant difference. Throughout the study, patients in both groups exhibited increased Barthel Index Scale scores from the study's initiation, and the scores for the observation group surpassed those of the control group, reaching statistical significance (P < .05). Furthermore, by the study's conclusion, anxiety and depression scores for patients in both groups were diminished compared to the study's commencement, and the observation group demonstrated significantly lower scores in anxiety and depression compared to the control group (P < .05). LESSONS: The implementation of nursing care grounded in the action research methodology exhibits a capacity to diminish both the occurrence and intensity of postoperative lymphedema in breast cancer patients. Concurrently, it enhances the patients' daily life functionality and mitigates symptoms of anxiety and depression.


Subject(s)
Breast Neoplasms , Lymphedema , Humans , Female , Breast Neoplasms/surgery , Breast Neoplasms/complications , Quality of Life , Research Design , Lymphedema/etiology , Lymphedema/prevention & control , Lymph Node Excision/adverse effects , Lymph Node Excision/methods
9.
J Agric Food Chem ; 70(37): 11804-11812, 2022 Sep 21.
Article in English | MEDLINE | ID: mdl-36070569

ABSTRACT

Sulfonamide antibiotics (SAs) are widely used in animal husbandry and aquaculture, and the excess residues of SAs in animal-derived foods will harm the health of consumers. In reality, various SAs were alternately used in animal husbandry and aquaculture, and thus, it is urgent need to develop simple and high-throughput methods for simultaneously detecting multiple SAs or groups of SAs in order to realize rapid screening of total SAs residues in animal-derived foods. We herein isolated a broad-specificity aptamer for SAs by using a multi-SAs systematic evolution of ligands by exponential enrichment (SELEX) strategy. The isolated broad-specificity aptamer has a higher binding affinity to five different SAs including sulfaquinoxaline (SQ), sulfamethoxypyridazine (SMPZ), sulfametoxydiazine (SMD), sulfachloropyridazine (SCP), and sulfapyridine (SPD) and, thus, can be used as a bioreceptor for developing various high-throughput methods for the simultaneous detection or rapid screening of above five SAs. Based on the isolated broad-specificity aptamer and Cy7 (diethylthiatricarbocyanine) displacement strategy, a colorimetric aptasensor was developed for the simultaneous detection of SQ, SMPZ, SMD, SCP, and SPD with a visual detection limit of 2.0-5.0 µM and a spectrometry detection limit of 0.2-0.5 µM. The colorimetric aptasensor was successfully used to detect SQ, SMPZ, SMD, SCP, and SPD in fish muscle with a recovery of 82%-92% and a RSD (n = 5) < 7%. The success of this study provided a promising bioreceptor for developing various high-throughput methods for on-site rapid screening of multiple SAs residues, as well as a simple method for the rapid and cost-effective screening of total SQ, SMPZ, SMD, SCP, and SPD in seafood.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Sulfachlorpyridazine , Sulfameter , Sulfamethoxypyridazine , Animals , Anti-Bacterial Agents/analysis , Fishes/metabolism , SELEX Aptamer Technique , Sulfanilamide , Sulfapyridine , Sulfaquinoxaline , Sulfonamides/chemistry
10.
Anal Chim Acta ; 1207: 339815, 2022 May 15.
Article in English | MEDLINE | ID: mdl-35491044

ABSTRACT

Here, a colorimetric aptasensor was constructed for sensitively detecting quinclorac (QNC), a common herbicide. The aptasensor involved a novel amplification strategy and a classical strand displacement strategy. The amplification strategy, termed exonuclease III (Exo III)-assisted cyclic release of phosphorodiamidate morpholino oligomer (PMO) mimic enzyme strategy, was developed based on two new findings on PMO: 1) DNA hybridized with PMO could resist Exo III digestion; 2) a designed G-rich PMO (named P2) could bind to hemin to form a G-quadruplex PMOzyme with peroxidase-like activity. In this strategy, a designed DNA-PMO duplex (D1-P1) completely hybridized with DNA2 (D2) in the other designed DNA-PMO duplex (D2-P2) to trigger D2 degradation by Exo III and cyclic release of P2. After that, the hemin-binding P2 catalyzed colorless tetra-methyl benzidine (TMB) to blue TMB+. The cycle process was performed at high Exo III concentrations without strict control and with constant background signals. In that case, the developed strategy was sensitive, efficient, easy to operate, reliable, and ultralow background. Meanwhile, a QNC aptamer was used to develop the strand displacement strategy based on magnetic beads. The colorimetric aptasensor was sensitive and selective for QNC detection with a detection limit of 7.1 ng mL-1. It was successfully applied to detect QNC in soil and river water with good recovery rates (92-98%) and a relative standard deviation (n = 3) <5%. The success of this study could provide a general reference strategy for developing sensitive aptasensors and other nucleic acid-related sensors.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Aptamers, Nucleotide/metabolism , Colorimetry , DNA , Exodeoxyribonucleases , Hemin , Morpholinos , Quinolines
11.
Talanta ; 245: 123489, 2022 Aug 01.
Article in English | MEDLINE | ID: mdl-35460981

ABSTRACT

On-site quantitative analysis of pesticides is important for food safety. Colorimetric gold nanobipyramids (AuNBPs) sensors are powerful methods for on-site detection. However, a single quantitative method and the instability of AuNBPs in solution limit the practicability of those sensors. Here, a paper-based multicolor AuNBPs sensor involved a colorimeter-assisted method for quantifying color was developed for quantitative detection of 2,4-dichlorophenoxyacetic acid (2,4-D), a common herbicide. The novelty of this study lies in developing a general paper-based quantitative on-site method (PQOM) for colorimetric AuNBPs sensors. Firstly, a paper-based analytical device (PAD) consisting of a nylon membrane, absorbent cotton layers, and two acrylic plates was fabricated to deposit AuNBPs. We demonstrated the PAD could improve the stability of AuNBPs and the detection sensitivity of AuNBPs sensors. Then, a handheld colorimeter was first used to quantify the color change of AuNBPs on the PAD based on the CIELab color space. Finally, as proof of concept, the PQOM was successfully employed to quantify 2,4-D by combining with an alkaline phosphatase-mediated AuNBPs growth method. In this method, 2,4-D specifically inhibited alkaline phosphatase activity to suppress the generation of l-ascorbic acid, thereby mediating AuNBPs growth. The developed sensor exhibited seven 2,4-D concentration-related colors and detected as low as 50 ng mL-1 2,4-D by naked-eye observation and 18 ng mL-1 2,4-D by a colorimeter. It was applied to detect 2,4-D in the spiked rice and apple samples with good recovery rates (91.8-112.0%) and a relative standard deviation (n = 5) < 5%. The success of this study provides a sensing platform for quantifying 2,4-D on site.


Subject(s)
Gold , Herbicides , 2,4-Dichlorophenoxyacetic Acid , Alkaline Phosphatase , Colorimetry/methods , Coloring Agents , Limit of Detection
12.
J Nurs Manag ; 30(7): 2881-2888, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35266237

ABSTRACT

AIMS: To investigate the knowledge sharing behaviour of critical care nurse specialists and identify potential influencing factors. BACKGROUND: The specialist knowledge of critical care nurses is an important resource for the nursing team. It is necessary to investigate influencing factors of knowledge sharing behaviour of them. METHODS: Convenience sampling was used to conduct an investigation involving critical care nurse specialists from three provinces in China between October 2018 and June 2019. Practice Environment Scale, Competency Inventory for Registered Nurses, Knowledge Self-efficacy Scale, and knowledge sharing behaviour scale were utilized. RESULTS: The knowledge sharing behaviour score of critical care nurse specialists was 64.84 ± 11.53. The results of the regression analysis showed that the level of education, position, involvement of nurses in hospital affairs, knowledge, self-efficacy, sex, average number of night shifts per month, years engaged in nursing work, type of employment, leadership skills, critical thinking ability and manpower and material resources accounted for 45.9% of the variance. CONCLUSIONS: Critical care nurse specialists exhibited limited knowledge sharing behaviour. Therefore, interventions based on the dependent variables are necessary. IMPLICATIONS FOR NURSING MANAGEMENT: Knowledge sharing behaviour of critical care nurse specialists remains at a low level. Hence, it is necessary to encourage their greater participation according to associated factors.


Subject(s)
Nurse Specialists , Humans , Cross-Sectional Studies , Critical Care , Knowledge , Leadership , Surveys and Questionnaires
13.
Bioresour Technol ; 350: 126862, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35183722

ABSTRACT

An acid-base bifunctional catacknalyst with coordinatively unsaturated cobalt-nitrogen active sites Co-Nx (x < 4) was synthesized to convert microalgal lipids with high acid value into biodiesel. Pyrolysis destroyed Co-N4 coordination structure in ZIF-67 and released coordinatively unsaturated Co-Nx and uncoordinated N sites, which resulted in the Lewis/Brønsted acid ratio increasing from 0.1 to 11.45 and the basicity increasing from 0.96 to 6.05 mmol/g. According to DFT calculations, the adsorption energy of free fatty acid (FFA) on Co-N2 site (-1.003 eV) exceeded that on Co-N4 site (-0.271 eV). The strong interaction between Co-N2 site and FFA increased electropositivity of carbonyl carbon atom in FFA from 1.379 to 1.529 eV and promoted esterification. The pyrolysis-induced defects generated more mesopores to promote the transportation of lipid molecules inside the catalyst. Therefore, the conversion efficiency of microalgal lipids into biodiesel over the ZC-450 catalyst (96.7%) was higher than that over the ZIF-67 catalyst (69.5%).


Subject(s)
Microalgae , Biofuels , Catalysis , Cobalt , Esterification , Fatty Acids , Fatty Acids, Nonesterified , Lipids/chemistry , Microalgae/chemistry , Nitrogen , Triglycerides
14.
Bioresour Technol ; 343: 126087, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34624467

ABSTRACT

To facilitate the lipid extraction from Nannochloropsis oceanica with thick cell wall using switchable hydrophilicity solvent, ultrasound-assisted N, N, N', N'-tetraethyl-1,3-propanediamine (TEPDA) was used to effectively destruct the cell wall. TEPDA cations were adsorbed on the cells via electrostatic force and formed the electron-donor-acceptor (EDA) complex with the hydroxyl groups in cellulose. This broke the hydrogen-bonding interactions between cellulose chains and stripped them from cell wall, thus reducing the cell wall thickness from 141 nm to 68.6 nm. Moreover, TEPDA cations neutralized the negatively charged phospholipid bilayers, decreasing the cell surface zeta potential from -27.5 eV to -14.1 eV. The local electrostatic equilibrium led to cell membrane leakage. The ultrasound promoted the stripping of the cellulose chains at a power intensity of 0.5 W/mL and frequency of 20 kHz, achieving the lipid extraction efficiency of 98.2% within 2 h at a volume ratio of 1:4 of wet microalgae to TEPDA.


Subject(s)
Microalgae , Biofuels , Biomass , Hydrophobic and Hydrophilic Interactions , Lipids , Solvents
15.
Bioresour Technol ; 345: 126479, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34864173

ABSTRACT

In order to optimize light distribution for promoting biomass growth rate of Chlorella pyrenoidosa, concave walls were installed in plate photobioreactors (PBR) to generate rotational flow field of microalgal solution circulated from top inlets to bottom outlets. Flow vortices in four corners of concave-wall PBR resulted in decreased mixing time and increased mass transfer coefficient. The CO2 bio-fixation by C. pyrenoidosa increased by 27% and chlorophyll-a concentration enhanced by 18.5% in concave-wall PBR compared to those in control (flat-wall) PBR. The concave walls diverge light rays to enhance frontal light exposure and supply more light photons into interior regions of PBRs. The promotion in light distribution and vortex flow field with concave walls enhanced light and nutrients utilization by microalgal cells, leading to an increased biomass growth rate by 21%.


Subject(s)
Chlorella , Microalgae , Biomass , Light , Photobioreactors
16.
Sci Total Environ ; 750: 141689, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-32871372

ABSTRACT

To simultaneously promote biomass yield and astaxanthin content of Haematococcus pluvialis, ammonium ferric citrate (AFC) was employed to stimulate light harvest in photosynthesis during the green stage and oxidation induction in astaxanthin accumulation during the red stage. AFC not only improved chlorophyll synthesis by 22.5% to provide more electrochemical potential energy in the green stage, but also alleviated photosystem II damage to maintain a high level of effective quantum yield by enhancing carotenoid production. The citrate derived from AFC stimulated acetyl-CoA and NADPH production through citric acid cycle and transaminase cycle during the red stage, resulting in an increased lipid content by 1.77-fold. The astaxanthin content in H. pluvialis cells cultivated with 5 µM AFC was 12.5% higher than that without AFC, which was attributed to severe oxidative stress caused by AFC through Haber-Weiss reaction. These results provided a new approach to reduce emission of greenhouse gasses with producing high-value products.


Subject(s)
Ammonium Compounds , Chlorophyta , Ferric Compounds , Light , Photosynthesis , Xanthophylls
17.
Sci Total Environ ; 760: 143405, 2021 Mar 15.
Article in English | MEDLINE | ID: mdl-33199017

ABSTRACT

In order to reutilize Fe2O3 particles in flue gas from coal-fired power plant as a ferrum nutrient for improving microalgae growth, Na-Citrate was proposed to chelate FeCl3 derived from Fe2O3 and HCl reactions to promote biomass and lipid productivities of Chlorella PY-ZU1. Fe-Citrate gave much higher biomass and lipid productivities than FeCl3, Fe-EDTA, Fe-DTPA and Fe-HEDTA, because organic chelator prevented Fe3+ from depositing, lower stability constant resulted in easier dissociation of ferric chelate, smaller chelate facilitated Fe2+ (reduced from Fe3+) transportation through cell membranes. The biomass growth and photosynthetic capacity of Chlorella PY-ZU1 cultivated with Fe-Citrate (converted from Fe2O3 particles) medium were similar to those with commercial ferric ammonium citrate medium. The biomass and lipid productivities of Chlorella PY-ZU1 cultivated with 5 mg L-1 Fe-Citrate medium were 1.30 and 1.72 times, respectively, higher than those with FeCl3 growth medium.


Subject(s)
Chlorella , Microalgae , Biomass , Carbon Dioxide , Coal , Lipids
18.
Anal Chim Acta ; 1139: 59-67, 2020 Dec 01.
Article in English | MEDLINE | ID: mdl-33190710

ABSTRACT

Dithiocarbamates (DTCs) pesticides were extensively used as fungicides in a variety of crops during their growth, storage and shipment. The DTCs residue in foods will seriously harm human health. In this study, a novel multicolor colorimetric sensor was developed for visual screening of total DTCs (total of ziram, thiram and zineb) based on sulfhydryl-mediated growth of gold nanobipyramids (AuNBPs). We demonstrated that DTCs can absorb on AuNBPs seed's surface via the formation of Au-S bonds and thus impede the 8-hydroxyquinoline (8-HQ)-promoted AuNBPs growth, which generates DTCs concentration-corresponding color changes. The developed sensor has vivid color changes, short analysis time, higher sensitivity and excellent specificity. It can be used to detect as low as 50 nM of total DTCs by bare eye observation and 17-18 nM of total DTCs by UV-visible spectrometry. By using the multicolor sensor, we have successfully screened total DTCs in apple and black tea by bare eye observation, and detected total DTCs in apple and black tea by UV-visible spectrometry with a recovery of 90%-104% and a relative standard deviation (RSD, n = 5) < 5%. The results obtained with our method consisted well with those obtained with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), verifying that our method had good accuracy and reliability. Especially, the visual detection limit of our method is much lower than the maximum residue limit of total DTCs in vegetable and fruits. All above features make our sensor a promising method for rapid on-site screening of total DTCs in vegetable and fruits by only bare eye observation.


Subject(s)
Pesticide Residues , Pesticides , Colorimetry , Gold , Humans , Pesticides/analysis , Reproducibility of Results , Tandem Mass Spectrometry
19.
Nucleic Acids Res ; 48(20): e120, 2020 11 18.
Article in English | MEDLINE | ID: mdl-33053182

ABSTRACT

In vitro aptamer isolation methods can yield hundreds of potential candidates, but selecting the optimal aptamer for a given application is challenging and laborious. Existing aptamer characterization methods either entail low-throughput analysis with sophisticated instrumentation, or offer the potential for higher throughput at the cost of providing a relatively increased risk of false-positive or -negative results. Here, we describe a novel method for accurately and sensitively evaluating the binding between DNA aptamers and small-molecule ligands in a high-throughput format without any aptamer engineering or labeling requirements. This approach is based on our new finding that ligand binding inhibits aptamer digestion by T5 exonuclease, where the extent of this inhibition correlates closely with the strength of aptamer-ligand binding. Our assay enables accurate and efficient screening of the ligand-binding profiles of individual aptamers, as well as the identification of the best target binders from a batch of aptamer candidates, independent of the ligands in question or the aptamer sequence and structure. We demonstrate the general applicability of this assay with a total of 106 aptamer-ligand pairs and validate these results with a gold-standard method. We expect that our assay can be readily expanded to characterize small-molecule-binding aptamers in an automated, high-throughput fashion.


Subject(s)
Aptamers, Nucleotide/chemistry , Exodeoxyribonucleases/chemistry , SELEX Aptamer Technique/methods , DNA/chemistry , Inverted Repeat Sequences , Ligands , Methamphetamine/analogs & derivatives , Methamphetamine/chemistry , Protein Binding
20.
Bioresour Technol ; 318: 124079, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32911369

ABSTRACT

Poor light utilization efficiency and large occupied area of traditional raceway pond photobioreactors result in low areal microalgal biomass yield in industrial applications. In this study, a pond-tubular hybrid photobioreactor (PTH-PBR) comprising raceway ponds and horizontal tubes was developed to strengthen flash light effect and improve areal microalgal biomass yield. The highest flash cycle frequency (0.63 Hz) of microalgae cells along flow pathway was obtained in the raceway pond of PTH-PBR when shaded area percentage was 20% and ratio of adjacent tube interval to tube diameter was 1, which enhanced microalgal biomass yield by 31.2% than traditional raceway pond. Meanwhile, intracellular chlorophyll content increased by 33.6% and PSII maximum quantum yield (Fv/Fm) increased by 8.1% due to decreased photoinhibition stress. The areal microalgal biomass yield of PTH-PBR was 54.7% higher than that of traditional raceway pond without horizontal tubes.


Subject(s)
Microalgae , Photobioreactors , Biomass , Light , Ponds
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