scholarly journals Bioaccumulation and detoxification of trivalent arsenic by Achromobacter xylosoxidans BHW-15 and electrochemical detection of its transformation efficiency

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farzana Diba ◽  
Md. Zaved Hossain Khan ◽  
Salman Zahir Uddin ◽  
Arif Istiaq ◽  
Md. Sadikur Rahman Shuvo ◽  
...  
Keyword(s):  
Transformation Efficiency ◽  
Cost Effective ◽  
Arsenic Species ◽  
Oxidation Potential ◽  
Achromobacter Xylosoxidans ◽  
Transformation Mechanism ◽  
Oxidase Enzyme ◽  
Arsenic Detoxification ◽  
Arsenite Oxidizing Bacteria ◽  
Mic Value

AbstractArsenotrophic bacteria play an essential role in lowering arsenic contamination by converting toxic arsenite [As (III)] to less toxic and less bio-accumulative arsenate [As (V)]. The current study focused on the qualitative and electrocatalytic detection of the arsenite oxidation potential of an arsenite-oxidizing bacteria A. xylosoxidans BHW-15 (retrieved from As-contaminated tube well water), which could significantly contribute to arsenic detoxification, accumulation, and immobilization while also providing a scientific foundation for future electrochemical sensor development. The minimum inhibitory concentration (MIC) value for the bacteria was 15 mM As (III). Scanning Electron Microscopy (SEM) investigation validated its intracellular As uptake capacity and demonstrated a substantial association with the MIC value. During the stationary phase, the strain’s As (III) transformation efficiency was 0.0224 mM/h. Molecular analysis by real-time qPCR showed arsenite oxidase (aioA) gene expression increased 1.6-fold in the presence of As (III) compared to the untreated cells. The immobilized whole-cell also showed As (III) conversion up to 18 days. To analyze the electrochemical oxidation in water, we developed a modified GCE/P-Arg/ErGO-AuNPs electrode, which successfully sensed and quantified conversion of As (III) into As (V) by accepting electrons; implying a functional As oxidase enzyme activity in the cells. To the best of our knowledge, this is the first report on the electrochemical observation of the As-transformation mechanism with Achromobactersp. Furthermore, the current work highlighted that our isolate might be employed as a promising candidate for arsenic bioremediation, and information acquired from this study may be helpful to open a new window for the development of a cost-effective, eco-friendly biosensor for arsenic species detection in the future.

scholarly journals Developing Activated Carbon Veil Electrode for Sensing Salivary Uric Acid

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 287
Author(s):  
Maria A. Bukharinova ◽  
Natalia Yu. Stozhko ◽  
Elizaveta A. Novakovskaya ◽  
Ekaterina I. Khamzina ◽  
Aleksey V. Tarasov ◽  
...  
Keyword(s):  
Uric Acid ◽  
Electrochemical Impedance ◽  
Linear Sweep Voltammetry ◽  
Cost Effective ◽  
Human Saliva ◽  
Charge Transfer Resistance ◽  
Oxidation Potential ◽  
Transfer Resistance ◽  
Highly Sensitive

The paper describes the development of a carbon veil-based electrode (CVE) for determining uric acid (UA) in saliva. The electrode was manufactured by lamination technology, electrochemically activated and used as a highly sensitive voltammetric sensor (CVEact). Potentiostatic polarization of the electrode at 2.0 V in H2SO4 solution resulted in a higher number of oxygen and nitrogen-containing groups on the electrode surface; lower charge transfer resistance; a 1.5 times increase in the effective surface area and a decrease in the UA oxidation potential by over 0.4 V, compared with the non-activated CVE, which was confirmed by energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, chronoamperometry and linear sweep voltammetry. The developed sensor is characterized by a low detection limit of 0.05 µM and a wide linear range (0.09–700 µM). The results suggest that the sensor has perspective applications for quick determination of UA in artificial and human saliva. RSD does not exceed 3.9%, and recovery is 96–105%. UA makes a significant contribution to the antioxidant activity (AOA) of saliva (≈60%). In addition to its high analytical characteristics, the important advantages of the proposed CVEact are the simple, scalable, and cost-effective manufacturing technology and the absence of additional complex and time-consuming modification operations.

scholarly journals Antioxidant activity of thymol essential oil and inhibition of polyphenol oxidase enzyme: a case study on the enzymatic browning of harvested longan fruit

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Muhammad Rafiullah Khan ◽  
Chongxing Huang ◽  
Hui Zhao ◽  
Haohe Huang ◽  
Liu Ren ◽  
...  
Keyword(s):  
Polyphenol Oxidase ◽  
Cost Effective ◽  
Antimicrobial Activities ◽  
Enzymatic Browning ◽  
Total Phenolic ◽  
Cost Effective Method ◽  
Wide Range ◽  
Oxidase Enzyme ◽  
Postharvest Life ◽  
Pericarp Browning

Abstract Background Enzymatic browning and microbial decay are the primary concerns that limit the postharvest life of longan fruit. These factors can be effectively prevented by sulfur dioxide (SO2) fumigation; however, due to the safety and regulatory issues of SO2, other alternatives must be tested. In this study, antioxidant and antimicrobial activities of thymol were determined against the pericarp browning and decay of longan fruit. A simple, cost-effective method was designed for its controlled release. Thymol vapors were obtained from the slurry prepared from 5 g of thymol in 5 mL of distilled water in a 180-mL glass jar, hermetically sealed and allowed for 24 h to accumulate the vapors in the headspace. Fruits were packed in polyethylene packages and fumigated with thymol through a septum. Non-fumigated fruits served as control and all the packages were stored at 25 ± 2 °C for 8 days. Results Thymol significantly (P ≤ 0.05) retarded pericarp browning (BI), delayed the decay incidence (DI) and maintained high color values of longan pericarp. Thymol also retained high total phenolic (TPC) and total flavonoid (TFC) contents, inhibited polyphenol oxidase (PPO) and peroxidase (POD) activities than those in control. A high coefficient of correlation of PPO with BI (r = 0.86), L* (r =  − 0.94), weight loss (r = 0.93), TPC (r =  − 0.77), TFC (r =  − 0.80), DI (r = 0.92) and many other quality and color parameters indicated the antioxidant efficacy of thymol. Longer shelf life of 8 days with good quality attributes was obtained in thymol-treated fruits than 6 days in control. Conclusion Thymol could be effectively used as a natural antioxidant for a wide range of fruits. Graphic abstract

scholarly journals Arsenic (As) Removal Using Talaromyces sp. KM-31 Isolated from As-Contaminated Mine Soil

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 568 ◽  
Author(s):  
Nam ◽  
Murugesan ◽  
Ryu ◽  
Kim
Keyword(s):  
Arsenic Removal ◽  
Cost Effective ◽  
Arsenic Species ◽  
Fungal Strain ◽  
Environmentally Benign ◽  
Mine Soil ◽  
Potato Dextrose Broth ◽  
Arsenic Tolerance ◽  
Cost Effective Approach ◽  
Removal Of Arsenic

: Bioremediation is an environmentally-benign and cost-effective approach to removing arsenic from contaminated areas. A fungal strain hyper-tolerant to arsenic was isolated from soil from a mine site and used for the removal of arsenic. The isolated fungus was identified as Talaromyces sp., and its growth rate, arsenic tolerance, and removal rates were investigated for As(III) and As(V). Arsenic tolerance tests revealed that the fungus was highly resistant to arsenic, tolerating concentrations up to 1000 mg/L. Robust mycelial growth was observed in potato dextrose broth containing either As(III) or As(V), and there was no difference in growth between that in arsenic-free medium and medium amended with up to 300 mg/L of either arsenic species. The isolate showed relatively low growth rates at As(V) concentrations >500 mg/L, and almost no growth at As(III) concentrations >300 mg/L. Both arsenic species were effectively removed from aqueous medium (>70%) in tests of the biosorption of arsenic onto mycelial biomass. Surface modification of the biomass with Fe(III) (hydr)oxides significantly enhanced arsenic removal efficiency. The findings indicate that this soil fungal strain has promise for use in bioremediation strategies to remove arsenic from highly contaminated aqueous systems.

scholarly journals Agrotransformation of Phytophthora nicotianae: a simplified and optimized method

2016 ◽  
Vol 42 (3) ◽  
pp. 254-256
Author(s):  
Ronaldo José Durigan Dalio ◽  
Paulo José Camargo dos Santos ◽  
Heros José Máximo ◽  
Pamela Ayumi Kawakami ◽  
Eduardo Goulin ◽  
...  
Keyword(s):  
Root Rot ◽  
Transformation Efficiency ◽  
Cost Effective ◽  
Phytophthora Nicotianae ◽  
The Other ◽  
Natural Ecosystems ◽  
High Transformation Efficiency ◽  
Citrus Root ◽  
High Transformation ◽  
Fluorescence Protein

ABSTRACT Phytophthora nicotianae is a plant pathogen responsible for damaging crops and natural ecosystems worldwide. P. nicotianae is correlated with the diseases: citrus gummosis and citrus root rot, and the management of these diseases relies mainly on the certification of seedlings and eradication of infected trees. However, little is known about the infection strategies of P. nicotianae interacting with citrus plants, which rises up the need for examining its virulence at molecular levels. Here we show an optimized method to genetically manipulate P. nicotianae mycelium. We have transformed P. nicotianae with the expression cassette of fluorescence protein DsRed. The optimized AMT method generated relatively high transformation efficiency. It also shows advantages over the other methods since it is the simplest one, it does not require protoplasts or spores as targets, it is less expensive and it does not require specific equipment. Transformation with DsRed did not impair the physiology, reproduction or virulence of the pathogen. The optimized AMT method presented here is useful for rapid, cost-effective and reliable transformation of P. nicotianae with any gene of interest.

scholarly journals Effect of different factors on regeneration and transformation efficiency of tomato (Lycopersicum esculentum) hybrids

2019 ◽  
Vol 55 (No. 3) ◽  
pp. 120-127
Author(s):  
Evangelia Stavridou ◽  
Nikoleta A. Τzioutziou ◽  
Panagiotis Madesis ◽  
Nikolaos E. Labrou ◽  
Irini Nianiou-Obeidat
Keyword(s):  
Genetic Transformation ◽  
Transformation Efficiency ◽  
Cost Effective ◽  
High Quality ◽  
Efficient Regeneration ◽  
Glycine Max L ◽  
Regeneration Efficiency ◽  
Genetic Transformation System

The current study aimed to produce rootstock material through micropropagation by developing efficient regeneration and Agrobacterium-mediated transformation protocols for three high quality commercial tomato hybrids (Felina, Siena and Don Jose) to overexpress the GmGSTU4 gene from Glycine max L. previously shown to enhance antioxidant activity. We investigated the plant growth regulators zeatin (Z) and 3-idoleacetic acid (IAA) to determine their best combination for an efficient regeneration protocol for each hybrid. The highest regeneration efficiency was observed in Felina (94.4%) with 1.0 mg/l Z and 0.1 mg/l IAA. In contrast, Don Jose (92.5%) and Siena (83.3%) performed better with 0.5 mg/l Z and 0.1 mg/l IAA. The three hybrids did not differ in micropropagation index, however, Felina showed the highest number of in vitro rooted and in vivo acclimatized plants. Factors such as the age of explant, days in pre- and co-culture and the concentrations of acetosyringone and thiamine on Agrobacterium-mediated genetic transformation were assessed. The transformation indices were 37.04% for the Felina, 13.8% for Siena and 8.33% for Don Jose. We conclude that targeted genotype-specific regeneration protocols will provide an efficient and cost effective genetic transformation system for rootstock production and further incorporation into micropropagation and transgrafting systems.  

Enrichment of arsenite oxidizing bacteria under autotrophic conditions and the isolation and characterization of facultative chemolithoautotrophic arsenite oxidizing bacteria for removal of arsenic from groundwater

2012 ◽  
Vol 12 (5) ◽  
pp. 707-714 ◽  
Author(s):  
L. Nguyen Ai ◽  
A. Sato ◽  
D. Inoue ◽  
K. Sei ◽  
S. Soda ◽  
...  
Keyword(s):  
Arsenic Removal ◽  
Enrichment Culture ◽  
Large Subunit ◽  
Cost Effective ◽  
Isolation And Characterization ◽  
The World ◽  
Genes Encoding ◽  
Arsenite Oxidizing Bacteria ◽  
Removal Of Arsenic

Arsenic contamination in groundwater has caused severe health problems throughout the world. Developing cost-effective processes for arsenic removal is an emerging issue. Because As(III) is predominant in groundwater and is more difficult to remove than As(V) is, oxidation of As(III) to As(V) is necessary to improve overall arsenic removal. This study was undertaken to enrich arsenite oxidizing bacteria under autotrophic conditions and to isolate and characterize facultative chemolithoautotrophic arsenite oxidizing bacteria (CAOs) that can oxidize As(III) effectively to As(V). An enrichment culture which adapted wide As(III) concentrations and completely oxidized 12 mM As(III) within 4 days under autotrophic conditions was established and maintained. Among 10 isolated strains, 6 strains, B1, B2, C, D, E1 and E2 belonging to β-Proteobacteria, were facultative CAOs and contained aoxB genes encoding the arsenite oxidase large subunit. Furthermore, they displayed various As(III) oxidation capabilities: B1, B2, E1 and E2 efficiently oxidized 1–10 mM As(III). The others showed efficient oxidation at 1–5 mM As(III), suggesting the coexistence of facultative CAOs with various As(III) oxidation capabilities in the enrichment. These results suggest that constructed enrichment and strains B1, B2, E1 and E2 can be useful for the bioremediation of arsenic-contaminated groundwater.

Managing Arsenic in the Environment

2006 ◽  
Author(s):  
Ravi Naidu ◽  
Euan Smith ◽  
Gary Owens ◽  
Prosun Bhattacharya ◽  
Peter Nadebaum
Keyword(s):  
Environmental Chemistry ◽  
Current Knowledge ◽  
Cost Effective ◽  
Arsenic Species ◽  
Arsenic Contamination ◽  
Future Research ◽  
Accurate Identification ◽  
Technological Advances ◽  
Remediation Strategies ◽  
Uptake Studies

Arsenic is one of the most toxic and carcinogenic elements in the environment. This book brings together the current knowledge on arsenic contamination worldwide, reviewing the field, highlighting common themes and pointing to key areas needing future research. Contributions discuss methods for accurate identification and quantification of individual arsenic species in a range of environmental and biological matrices and give an overview of the environmental chemistry of arsenic. Next, chapters deal with the dynamics of arsenic in groundwater and aspects of arsenic in soils and plants, including plant uptake studies, effects on crop quality and yield, and the corresponding food chain and human health issues associated with these exposure pathways. These concerns are coupled with the challenge to develop efficient, cost effective risk management and remediation strategies: recent technological advances are described and assessed, including the use of adsorbants, photo-oxidation, bioremediation and electrokinetic remediation. The book concludes with eleven detailed regional perspectives of the extent and severity of arsenic contamination from around the world. It will be invaluable for arsenic researchers as well as environmental scientists and environmental chemists, toxicologists, medical scientists, and statutory authorities seeking an in-depth view of the issues surrounding this toxin.

The oxidation of Inconel alloy MA754 at low oxidation potential

1983 ◽  
Vol 41 ◽  
pp. 218-219
Author(s):  
D. N. Braski ◽  
P. D. Goodell ◽  
J. V. Cathcart ◽  
R. H. Kane
Keyword(s):  
Surface Layer ◽  
Oxidation Potential ◽  
Metal Interface ◽  
Elevated Temperature Strength ◽  
Surface Conditions ◽  
Inconel Alloy ◽  
Inco Alloy ◽  
Resistance To Oxidation ◽  
Oxide Particles ◽  
Cold Worked

It has been known for some time that the addition of small oxide particles to an 80 Ni—20 Cr alloy not only increases its elevated-temperature strength, but also markedly improves its resistance to oxidation. The mechanism by which the oxide dispersoid enhances the oxidation resistance is being studied collaboratively by ORNL and INCO Alloy Products Company.Initial experiments were performed using INCONEL alloy MA754, which is nominally: 78 Ni, 20 Cr, 0.05 C, 0.3 Al, 0.5 Ti, 1.0 Fe, and 0.6 Y2O3 (wt %).Small disks (3 mm diam × 0.38 mm thick) were cut from MA754 plate stock and prepared with two different surface conditions. The first was prepared by mechanically polishing one side of a disk through 0.5 μm diamond on a syntron polisher while the second used an additional sulfuric acid-methanol electropolishing treatment to remove the cold-worked surface layer. Disks having both surface treatments were oxidized in a radiantly heated furnace for 30 s at 1000°C. Three different environments were investigated: hydrogen with nominal dew points of 0°C, —25°C, and —55°C. The oxide particles and films were examined in TEM by using extraction replicas (carbon) and by backpolishing to the oxide/metal interface. The particles were analyzed by EDS and SAD.

The application of electron microscopy to diagnosis in gynecologic neoplasms and tumor-like conditions

1984 ◽  
Vol 42 ◽  
pp. 102-105
Author(s):  
Lawrence M. Roth
Keyword(s):  
Electron Microscopy ◽  
Reproductive Tract ◽  
Malignant Tumors ◽  
Frozen Section ◽  
Cost Effective ◽  
Female Reproductive Tract ◽  
Ultrastructural Examination ◽  
Specific Diagnosis ◽  
Potential Value ◽  
Gynecologic Neoplasms

The female reproductive tract may be the site of a wide variety of benign and malignant tumors, as well as non-neoplastic tumor-like conditions, most of which can be diagnosed by light microscopic examination including special stains and more recently immunoperoxidase techniques. Nevertheless there are situations where ultrastructural examination can contribute substantially to an accurate and specific diagnosis. It is my opinion that electron microscopy can be of greatest benefit and is most cost effective when applied in conjunction with other methodologies. Thus, I have developed an approach which has proved useful for me and may have benefit for others. In cases where it is deemed of potential value, glutaraldehyde-fixed material is obtained at the time of frozen section or otherwise at operation. Coordination with the gynecologic oncologist is required in the latter situation. This material is processed and blocked and is available if a future need arises.

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