A review on catalytic-enzyme degradation of toxic environmental pollutants: Microbial enzymes

2021 ◽  
pp. 126451
Author(s):  
A. Saravanan ◽  
P. Senthil Kumar ◽  
Dai-Viet N. Vo ◽  
S. Jeevanantham ◽  
S. Karishma ◽  
...  
Keyword(s):  
Environmental Pollutants ◽  
Microbial Enzymes ◽  
Enzyme Degradation

Polychlorinated biphenyl induced hepatocyte alterations

1987 ◽  
Vol 45 ◽  
pp. 716-717
Author(s):  
D.N. Collins ◽  
J.N. Turner ◽  
K.O. Brosch ◽  
R.F. Seegal
Keyword(s):  
Lipid Droplets ◽  
Wistar Rats ◽  
Homovanillic Acid ◽  
Polychlorinated Biphenyl ◽  
Corn Oil ◽  
Environmental Pollutants ◽  
Short Term ◽  
Pcb Congeners ◽  
Urinary Levels ◽  
The Brain

Polychlorinated biphenyls (PCBs) are a ubiquitous class of environmental pollutants with toxic and hepatocellular effects, including accumulation of fat, proliferated smooth endoplasmic recticulum (SER), and concentric membrane arrays (CMAs) (1-3). The CMAs appear to be a membrane storage and degeneration organelle composed of a large number of concentric membrane layers usually surrounding one or more lipid droplets often with internalized membrane fragments (3). The present study documents liver alteration after a short term single dose exposure to PCBs with high chlorine content, and correlates them with reported animal weights and central nervous system (CNS) measures. In the brain PCB congeners were concentrated in particular regions (4) while catecholamine concentrations were decreased (4-6). Urinary levels of homovanillic acid a dopamine metabolite were evaluated (7).Wistar rats were gavaged with corn oil (6 controls), or with a 1:1 mixture of Aroclor 1254 and 1260 in corn oil at 500 or 1000 mg total PCB/kg (6 at each level).

Computers and Iatrocomplexities

1966 ◽  
Vol 05 (04) ◽  
pp. 167-171 ◽  
Author(s):  
L. E. Faer
Keyword(s):  
Twentieth Century ◽  
Cigarette Smoke ◽  
Environmental Pollutants ◽  
Genetic Composition ◽  
Koch’S Postulates ◽  
Lung Malignancies ◽  
Causative Agents ◽  
Disease Study ◽  
Multiple Etiology ◽  
Great Advance

Developments of disease hypotheses and conceptions of disease as philosophic entities have shown bursts of great advance. One just concluded includes emergence of bacteriology and virology culminating in Koch’s Postulates, which in the twentieth century were primary bases for disease study and colored all approaches to medicine.With recent extraordinary advances in technology, medicine faces great new obligations demanding fresh approaches and untrammeled thinking for solution of problems posed. It is clear that any approach to diseases and disabilities induced by exposures to environmental pollutants must take multiple etiology into account. For example, contributing to causation of lung malignancies one must list usual dusts, radioactivity, smog, auto exhausts, cigarette smoke and genetic composition. Consideration of plural factors in genesis of environmentally associated disease leads to the hypothesis of the incremental insult, a complex and difficult conception in which must be included provision for multiple causative agents, each contributing but a fraction toward total etiology^ Computers developed to their present refinement provide necessary tools for whatever complexity required to spawn and fructify hypotheses of inter-relating associations of incremental insults leading to pathology.

EPEGENTIC TOXICOLOGY: PERSPECTIVES OF THE DEVELOPMENT

2018 ◽  
pp. 2-7
Author(s):  
G. A. Sofronov ◽  
E. L. Patkin
Keyword(s):  
Public Health ◽  
Life Cycle ◽  
Human Health ◽  
Chronic Exposure ◽  
Environmental Pollutants ◽  
Epigenetic Mechanisms ◽  
Epigenetic Changes ◽  
Mechanism Of Formation ◽  
Health Disorders ◽  
Time Periods

One of the complex problems of modern experimental toxicology remains the molecular mechanism of formation of human health disorders separated at different time periods from acute or chronic exposure to toxic environmental pollutants (ecotoxicants). Identifying and understanding what epigenetic changes are induced by the environment, and how they can lead to unfavorable outcome, are vital for protecting public health. Therefore, we consider it important a modern understanding of epigenetic mechanisms involved in the life cycle of mammals and assess available data on the environmentally caused epigenetic toxicity and, accordingly fledging epigenenomic (epigenetic) regulatory toxicology.

Microbial enzymes used in prodrug activation for cancer therapy: Insights and future perspectives

2020 ◽  
Vol 21 ◽  
Author(s):  
Rakhi Dhankhar ◽  
Anubhuti Kawatra ◽  
Aparajita Mohanty ◽  
Pooja Gulati
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Cytosine Deaminase ◽  
Therapeutic Index ◽  
Enzyme Prodrug Therapy ◽  
Prodrug Activation ◽  
Microbial Enzymes ◽  
High Productivity ◽  
Delivery Vector ◽  
Exogenous Enzymes ◽  
Activation Therapy

Abstract:: Enzyme prodrug therapy has gained momentum in the recent years due to their ability to improve therapeutic index (benefits versus toxic side-effects) and efficacy of chemotherapy in cancer treatment. Inactive prodrugs used in this system are converted into active anti-cancerous drugs by enzymes, specifically within the tumor cells. This therapy involves three components namely prodrug, enzyme and gene delivery vector. Past reports have clearly indicated that the choice of enzyme used, is the major determinant for the success of this therapy. Generally, enzymes from non-human sources are employed to avoid off-target toxicity. Exogenous enzymes also give a better control to the clinician regarding the calibration of treatment by site-specific initiation. Amongst these exo-enzymes, microbial enzymes are preferred due to their high productivity, stability and ease of manipulation. The present review focuses on the commonly used microbial enzymes particularly cytosine deaminase, nitroreductase, carboxypeptidase, purine nucleoside phosphorylase in prodrug activation therapy. Various aspects viz. source of the enzymes, types of cancer targeted, mode of action and efficacy of the enzyme/prodrug system, efficient vectors used and recent research developments of each of these enzymes are comprehensively elaborated. Further, the results of the clinical trials and various strategies to improve their clinical applicability are also discussed.

Recent Trends in Development of Nanomaterials Based Green Analytical Methods for Environmental Remediation

2020 ◽  
Vol 16 ◽  
Author(s):  
Sidra Amin ◽  
Amber R. Solangi ◽  
Dilawar Hassan ◽  
Nadir Hussain ◽  
Jamil Ahmed ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Environmental Remediation ◽  
Environmental Chemistry ◽  
Limit Of Detection ◽  
Environmental Pollutants ◽  
Toxic Metal ◽  
Electrochemical Analysis ◽  
Good Choice ◽  
Nano Materials ◽  
Limit Of Quantification

Background: In recent years, the occurrence and fate of environmental pollutants has been recognized as one of the emerging issues in environmental chemistry. A survey documented about a wide variety of these pollutants, which are often detected in our environment and these are major cause of shortened life spans and the global warming. These pollutants include toxic metal, pesticides, fertilizers, drugs and dyes released into soil and major water bodies. The presence of these contaminants causes major disturbance in eco-system’s balance. To tackle these issues many technological improvements are made to detect minute contaminations. The latest issue being answered by the scientists is the use of green nano materials as sensors which are economical, instant and give much better results at low concentrations and can be used for the field measurements resulting in no dangerous by-product that could lead to more environmental contamination. Nano materials are known for their wide band gap, enhanced physical and optical properties with option of tuneablity as per need, by optimizing certain parameters. They are proved to be good choice for analytical/optical sensors with high sensitivity. Objective: This review holds information about multiple methods that use green nanomaterials for the analytical assessment of environmental pollutants. UV-Vis spectrophotometry and electrochemical analysis using green and reproducible nanomaterials are the major focus of this review article. To date, there are number of spectrophotometric and electro chemical methods available that have been used for the detection of environmental pollutants such as toxic metals, pesticides and dyes. Conclusion: The use of nanomaterials can drastically change the detection limits due to having large surface area, strong catalytic properties, and tunable possibility. With the use of nano materials, lower than the marked limit of detection and limit of quantification were seen when compared with previously reported work. The used nano-materials could be washed, dried, and reused, which makes the methods more proficient, cost effective and environmentally friendly.

Multi-chain action of exo-D-galacturonanase from carrot

1983 ◽  
Vol 48 (12) ◽  
pp. 3579-3588
Author(s):  
Kveta Heinrichová ◽  
Jana Perečková
Keyword(s):  
Optimal Condition ◽  
Degradation Products ◽  
Degradation Kinetics ◽  
Hydrolytic Cleavage ◽  
Chain Mechanism ◽  
Modes Of Action ◽  
Enzyme Degradation ◽  
Good Agreement

Two possible modes of action of exo-D-galacturonanase from carrot (E.C. 3.2.1.67) were investigated; this enzyme catalyses the sequential hydrolytic cleavage of pectants and oligogalacturonans by a terminal action from the nonreducing end of the molecule. The experiments indicate that the investigated exo-D-galacturonanase degrades these substrates by a predominantly multi-chain mechanism. Distribution of degradation products of oligomeric substrates (hexa- and pentagalacturonide) under an optimal condition for the action of the enzyme (pH and temperature) indicates that a multi-chain enzyme attack with a prevalent simple collision is involved. Results of the enzyme degradation kinetics are in a good agreement with the above-mentioned presumption.

scholarly journals The Role of the Human Microbiome in Chemical Toxicity

2019 ◽  
Vol 38 (4) ◽  
pp. 251-264 ◽  
Author(s):  
Jason M. Koontz ◽  
Blair C. R. Dancy ◽  
Cassandra L. Horton ◽  
Jonathan D. Stallings ◽  
Valerie T. DiVito ◽  
...  
Keyword(s):  
Health Outcomes ◽  
Human Microbiome ◽  
Chemical Exposure ◽  
Environmental Chemicals ◽  
Microbial Interactions ◽  
World Population ◽  
Toxic Exposure ◽  
Chemical Toxicity ◽  
Microbial Enzymes ◽  
Overwhelming Evidence

There is overwhelming evidence that the microbiome must be considered when evaluating the toxicity of chemicals. Disruption of the normal microbial flora is a known effect of toxic exposure, and these disruptions may lead to human health effects. In addition, the biotransformation of numerous compounds has been shown to be dependent on microbial enzymes, with the potential for different host health outcomes resulting from variations in the microbiome. Evidence suggests that such metabolism of environmental chemicals by enzymes from the host's microbiota can affect the toxicity of that chemical to the host. Chemical-microbial interactions can be categorized into two classes: Microbiome Modulation of Toxicity (MMT) and Toxicant Modulation of the Microbiome (TMM). MMT refers to transformation of a chemical by microbial enzymes or metabolites to modify the chemical in a way that makes it more or less toxic. TMM is a change in the microbiota that results from a chemical exposure. These changes span a large magnitude of effects and may vary from microbial gene regulation, to inhibition of a specific enzyme, to the death of the microbes. Certain microbiomes or microbiota may become associated with different health outcomes, such as resistance or susceptibility to exposure to certain toxic chemicals, the ability to recover following a chemical-induced injury, the presence of disease-associated phenotypes, and the effectiveness of immune responses. Future work in toxicology will require an understanding of how the microbiome interacts with toxicants to fully elucidate how a compound will affect a diverse, real-world population.

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