An endosulfan-degrading mixed bacterial culture was enriched from soil with a history of endosulfan exposure. Enrichment was obtained by using the insecticide as the sole source of sulfur. Chemical hydrolysis was minimized by using strongly buffered culture medium (pH 6.6), and the detergent Tween 80 was included to emulsify the insecticide, thereby increasing the amount of endosulfan in contact with the bacteria. No growth occurred in control cultures in the absence of endosulfan. Degradation of the insecticide occurred concomitant with bacterial growth. The compound was both oxidized and hydrolyzed. The oxidation reaction favored the alpha isomer and produced endosulfate, a terminal pathway product. Hydrolysis involved a novel intermediate, tentatively identified as endosulfan monoaldehyde on the basis of gas chromatography-mass spectrometry and chemical derivatization results. The accumulation and decline of metabolites suggest that the parent compound was hydrolyzed to the putative monoaldehyde, thereby releasing the sulfite moiety required for growth. The monoaldehyde was then oxidized to endosulfan hydroxyether and further metabolized to (a) polar product(s). The cytochrome P450 inhibitor, piperonyl butoxide, did not prevent endosulfan oxidation or the formation of other metabolites. These results suggest that this mixed culture is worth investigating as a source of endosulfan-hydrolyzing enzymes for use in enzymatic bioremediation of endosulfan residues.

/pdf/enrichment-of-an-endosulfan-degrading-mixed-bacterial-1z35q5xe8r.pdf

Enrichment of an endosulfan-degrading mixed bacterial culture.

Enzymes are central to the biology of many pesticides, influencing their modes of action, environmental fates and mechanisms of target species resistance. Since the introduction of synthetic xenobiotic pesticides, enzymes responsible for pesticide turnover have evolved rapidly, in both the target organisms and incidentally exposed biota. Such enzymes are a source of significant biotechnological potential and form the basis of several bioremediation strategies intended to reduce the environmental impacts of pesticide residues. This review describes examples of enzymes possessing the major activities employed in the bioremediation of pesticide residues, and some of the strategies by which they are employed. In addition, several examples of specific achievements in enzyme engineering are considered, highlighting the growing trend in tailoring enzymatic activity to a specific biotechnologically relevant function.

/pdf/the-enzymatic-basis-for-pesticide-bioremediation-50m8ajpzcs.pdf

The enzymatic basis for pesticide bioremediation

The addition of isolated bacterial cells to contaminated soils causes an enhanced degradation of endosulfan isomers. Various factors, including the additional presence of carbon sources, pH, moisture content, concentration of endosulfan, and size of inoculum, influenced the degradation of endosulfan isomers. The degradation was faster in wet soils, as compared with the flooded soils, and was inhibited by the presence of additional carbon sources such as sodium acetate and sodium succinate. The degradation of endosulfan was not detectable at acidic pH and increased gradually to reach an optimal activity at pH 8.5. It chemically converts into endosulfan diol at higher pH values. The rate of biodegradation progressed with the increase in endosulfan concentration up to 5.0 mg g−1 soil, followed by an inhibitory effect at higher concentrations, reaching a total loss of biodegradative activity at 10 mg g−1 soil. The addition of 2×106 bacterial cells g−1 soil was optimal for endosulfan degradation and any further increase in inoculum size was of no additional advantage. Initial optimization of these factors is, therefore, essential for successful bioremediation.

/pdf/factors-influencing-the-degradation-of-soil-applied-23aodtrfb9.pdf

Factors influencing the degradation of soil-applied endosulfan isomers

Quick review of word parts, plurals, and symbols. Med Terminology arranged by word parts to English and English to word parts. Common abbreviations. Conversion (time, temperature, systems of measurement. Normal values for vitals. Communication tips. Dosage calc (formula, ratio/proportion, and dimensional analysis. Six rights of medicine administration. 4-color insert with body system art.

/pdf/toxicological-profile-for-malathion-35h2x4bufr.pdf

Toxicological profile for malathion

The characterization of runoff-related pesticide input and the identification of areas of concern in the field are essential for a comprehensive assessment of risk and the planning of mitigation measures. To this end, the agriculturally-derived aqueous and particle-associated pesticide contamination of the Lourens River and its tributaries was measured in a comprehensive design. Sampling was performed in the beginning of April prior to the first rainfall of the wet season and in the middle of April during high water conditions following the first rainfall of 9.6 mm d-1. Pre-runoff samples indicated contamination with endosulfan at levels up to 0.06 μg L-1, while no other pesticides were detectable. Rainfall-induced runoff resulted in an increase in the levels of the pesticides endosulfan, deltamethrin, azinphos-methyl, chlorpyrifos, and procymidone up to levels of 0.35, 1.4, 0.6, 0.19 and 9 μg L-1, respectively in water samples. Endosulfan, azinphos-methyl, and chlorpyrifos were detected at maximum concentrations of 273, 152, and 245 μg kg-1 in suspended sediments. No increased pesticide levels were detected at a control site upstream of the agricultural area. The Lourens River received its contamination via the tributaries discharging the surrounding farming area. Contamination of the six tributaries depended on landuse and slope characteristics and enabled the identification of target sites for risk reduction approaches. Transient pesticide levels exceeded the target water quality limit proposed by the South African Department of Water Affairs and Forestry (DWAF). The Lourens River site downstream of the farming area has been identified as a site where potential toxic conditions could arise.

Runoff-Related Pesticide Input into the Lourens River, South Africa: Basic Data for Exposure Assessment and Risk Mitigation at the Catchment Scale

Endosulfan is an insecticide possessing a relatively broad spectrum of activity ; as a cyclic sulfite ester, it differs from the chlorinated hydrocarbons of the cyclodiene group by its physiological properties and behavior in the organism as well as by its extremely sparing action on beneficial insects. The technical active substance consists of two isomers, α- and β-endosulfan, which both possess similar insecticidal properties. Endosulfan was synthesized at Hoechst Aktiengesellschaft by Frensch and Goebel (1954 and 1954 a), the insecticidal effect of which was discovered by Frensch et al. (1954 b), and brought onto the market under the registered trade name Thiodan®.

Properties, Effects, Residues, and Analytics of the insecticide Endosulfan

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

S. Gorbach

Author Tools

Chat about Author

Papers

Properties, Effects, Residues, and Analytics of the insecticide Endosulfan