scholarly journals Characterization of deltamethrin degradation and metabolic pathway by co-culture of Acinetobacter junii LH-1-1 and Klebsiella pneumoniae BPBA052

2020 ◽  
Author(s):  
Jie Tang ◽  
Qiong Hu ◽  
Dan Lei ◽  
Min Wu ◽  
Chaoyi Zeng ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Contaminated Soils ◽  
Degradation Kinetics ◽  
Degradation Pathway ◽  
Gas Chromatography Mass Spectrometry ◽  
Acinetobacter Junii ◽  
Pyrethroid Pesticides ◽  
First Time ◽  
Kinetics Of

Abstract Deltamethrin and its major metabolite 3-phenoxybenzoic acid (3‐PBA) have caused serious threat to the environment as well as human health, yet little is known about their degradation pathways by bacterial co-cultures. In this study, the growth and degradation kinetics of Acinetobacter junii LH-1-1 and Klebsiella pneumoniae BPBA052 during deltamethrin and 3-PBA degradation were established, respectively. When the inoculum proportion of the strains LH-1-1 and BPBA052 was 7.5:2.5, and LH-1-1 was inoculated 24 h before inoculation of strain BPBA052, 94.25% deltamethrin was degraded and 9.16 mg/L of 3-PBA remained within 72 h, which was 20.36% higher and 10.25 mg/L lesser than that in monoculture of LH-1-1, respectively. And the half-life of deltamethrin was shortened from 38.40 h to 24.58 h. Based on gas chromatography–mass spectrometry, 3-phenoxybenzaldehyde, 1,2-benzenedicarboxylic butyl dacyl ester, and phenol were identified as metabolites during deltamethrin degradation in co-culture. This is the first time that a co-culture degradation pathway of deltamethrin has been proposed based on these identified metabolites. Bioremediation of deltamethrin-contaminated soils with co-culture of strains LH-1-1 and BPBA052 significantly enhanced deltamethrin degradation and 3-PBA removal. This study provides a platform for further studies on deltamethrin and 3-PBA biodegradation mechanism in co-culture, and it also proposes a promising approach for efficient bioremediation of environment contaminated by pyrethroid pesticides and their associated metabolites.

scholarly journals Analysis of amphetamines illegally produced in Serbia

2008 ◽  
Vol 73 (7) ◽  
pp. 691-701 ◽  
Author(s):  
Marina Nevescanin ◽  
Sonja Banovic-Stevic ◽  
Slobodan Petrovic ◽  
Vlatka Vajs
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Chemical Characterization ◽  
Gas Chromatography Mass Spectrometry ◽  
Active Components ◽  
Forensic Practice ◽  
The Republic ◽  
Phosphate Salts ◽  
First Time

Forensic practice in the Republic of Serbia faced the illegal production of amphetamine for the first time in 2003. This paper presents the results of the chemical characterization of 32 batches of amphetamine samples from three separate cases, for the purpose of identification of the active components and additives. Through the profiling of impurities of all samples, using gas chromatography/mass spectrometry (GC/MS), 30 compounds associated with amphetamine were identified. The results of the analysis of powder tartrate, sulfate and phosphate salts of amphetamine, as well as variously formulated tablets are presented in this study. The analyses showed that the amphetamines were synthesized by the Leuckart method in all cases. .

scholarly journals Characterization of Multidrug-resistant and Virulent Klebsiella Pneumoniae Strains Belonging to the High-risk CG258 Isolated from Inpatients in Northeastern Brazil

2021 ◽  
Author(s):  
Rafael Nakamura-Silva ◽  
Mariana Oliveira-Silva ◽  
João Pedro Rueda Furlan ◽  
Eliana Guedes Stehling ◽  
Carlos Eduardo Saraiva Miranda ◽  
...  
Keyword(s):  
High Risk ◽  
Klebsiella Pneumoniae ◽  
Tertiary Hospital ◽  
Multidrug Resistant ◽  
Northeastern Brazil ◽  
Hospital Environment ◽  
Global Public Health ◽  
Antimicrobial Resistance Profile ◽  
First Time

Abstract Multidrug-resistant (MDR) and hypervirulent Klebsiella pneumoniae (hvKp) clones have become a major threat to global public health. The CG258 is considered a high-risk CG and the K. pneumoniae strains belonging to it are known to be often multi-resistant and to spread mainly in the hospital environment. This study aimed to characterize the antimicrobial resistance profile, virulence factors, and the clonal relationships among 13 K. pneumoniae strains belonging to CG258 from patients admitted to a tertiary hospital in Teresina, in the state of Piauí, northeastern Brazil. Ten strains were classified as MDR and three as extensively drug-resistant (XDR). Three different β-lactamase-encoding genes ( bla KPC , bla OXA-1- like , and bla CTX-M-Gp1) and six virulence genes ( fimH , ycfM , mrkD , entB , ybtS , and kfu ) were detected. Moreover, two hypermucoviscous K. pneumoniae strains and one capsular K-type 2 were found. Multilocus sequence typing analysis revealed 10 different sequence types (STs) (ST14, ST17, ST20, ST29, ST45, ST101, ST268, ST1800, ST3995, and ST3996) belonging to CG258, being two (ST3995 and ST3996) described for the first time in this study.

scholarly journals Photo degradation kinetics of insensitive munitions constituents nitroguanidine, nitrotriazolone, and dinitroanisole in natural waters

2021 ◽  
Author(s):  
Lee Moores ◽  
Stacy Jones ◽  
Garrett George ◽  
David Henderson ◽  
Timothy Schutt
Keyword(s):  
Laboratory Experiments ◽  
Natural Waters ◽  
Matrix Effects ◽  
Degradation Kinetics ◽  
Relative Rate ◽  
Ph Dependence ◽  
Degradation Pathway ◽  
Quantum Yields ◽  
The Individual ◽  
Kinetics Of

Herein the matrix effects on the kinetics of aqueous photolysis for the individual munitions constituents of IMX-101: nitroguanidine (NQ), dinitroanisole (DNAN), and nitrotriazolone (NTO) are reported along with the environmentally relevant kinetics and quantum yields. Photolysis potentially represents a major degradation pathway for these munitions in the environment and further understanding the complex matrices effects on photolytic kinetics was needed. Aqueous systems are of particular interest due to the high solubility of NQ (3,800 ppm) and NTO (16,642 ppm) compared to the traditional munitions trinitrotoluene (TNT, 100.5 ppm) and 1,3,5-trinitro-1,3,5-triazine (RDX, 59.9 ppm). Environmental half-lives (and quantum yields) were found to be 0.44 days, 0.83 days, and 4.4 days for NQ, DNAN, and NTO, respectively, under natural sunlight. In laboratory experiments using nominally 300 nm bulbs in a merry-go-round style reactor in DI water the relative rate of photolysis for the three munitions constituents followed the same order NQ > DNAN > NTO, where DNAN and NTO reacted 57 and 115 times more slowly, respectively, than NQ. In the various environmentally relevant matrices tested in the laboratory experiments NQ was not significantly affected, DNAN showed a faster degradation with increasing ionic strength, and NTO showed a modest salinity and pH dependence on its rate of photolysis.

scholarly journals Cryoenzymology of trypsin. 13C-n.m.r. detection of an acyl-trypsin intermediate in the trypsin-catalysed hydrolysis of a highly specific substrate at subzero temperature

1984 ◽  
Vol 219 (2) ◽  
pp. 437-444 ◽  
Author(s):  
N E Mackenzie ◽  
J P Malthouse ◽  
A I Scott
Keyword(s):  
Subzero Temperature ◽  
Specific Substrate ◽  
Visible Absorption ◽  
Enzyme Substrate ◽  
First Time ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Nitrophenyl Ester

The kinetics of the trypsin-catalysed hydrolysis of the highly specific substrate N alpha-benzyloxycarbonyl-L-lysine p-nitrophenyl ester were studied under cryoenzymological conditions by 13C-n.m.r. spectroscopy at pH approx. 3.0. The kinetics of this reaction are shown to be in agreement with similar studies made with the use of u.v.-visible-absorption-spectrophotometric techniques. A combination of 13C-n.m.r. spectroscopy and cryoenzymology has for the first time detected an acyl-trypsin intermediate in the hydrolysis of this highly specific substrate. The advantages and difficulties of using 13C-n.m.r. spectroscopy coupled with cryoenzymology in the detection and characterization of enzyme-substrate intermediates are discussed.

Characterization of naphthalene degradation by Streptomyces sp. QWE-5 isolated from active sludge

2014 ◽  
Vol 70 (6) ◽  
pp. 1129-1134 ◽  
Author(s):  
Peng Xu ◽  
Wencheng Ma ◽  
Hongjun Han ◽  
Baolin Hou ◽  
Shengyong Jia
Keyword(s):  
Degradation Rate ◽  
Substrate Inhibition ◽  
Degradation Pathway ◽  
Active Sludge ◽  
Streptomyces Sp ◽  
Metabolic Intermediates ◽  
Naphthalene Degradation ◽  
Specific Degradation ◽  
Kinetics Of

A bacterial strain, QWE-5, which utilized naphthalene as its sole carbon and energy source, was isolated and identified as Streptomyces sp. It was a Gram-positive, spore-forming bacterium with a flagellum, with whole, smooth, convex and wet colonies. The optimal temperature and pH for QWE-5 were 35 °C and 7.0, respectively. The QWE-5 strain was capable of completely degrading naphthalene at a concentration as high as 100 mg/L. At initial naphthalene concentrations of 10, 20, 50, 80 and 100 mg/L, complete degradation was achieved within 32, 56, 96, 120 and 144 h, respectively. Kinetics of naphthalene degradation was described using the Andrews equation. The kinetic parameters were as follows: qmax (maximum specific degradation rate) = 1.56 h−1, Ks (half-rate constant) = 60.34 mg/L, and KI (substrate-inhibition constant) = 81.76 mg/L. Metabolic intermediates were identified by gas chromatography and mass spectrometry, allowing a new degradation pathway for naphthalene to be proposed. In this pathway, monooxygenation of naphthalene yielded naphthalen-1-ol. Further degradation by Streptomyces sp. QWE-5 produced acetophenone, followed by adipic acid, which was produced as a combination of decarboxylation and hydroxylation processes.

Migration Characteristics and Degradation Kinetics of Bisphenol A

2016 ◽  
Vol 850 ◽  
pp. 128-136
Author(s):  
Zhuo Jun Sun ◽  
Jian Gao ◽  
Hui Liu ◽  
Shu Zhen Pan ◽  
Shu Li Zhang ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Bisphenol A ◽  
Aging Time ◽  
Degradation Kinetics ◽  
Heat Stability ◽  
Gas Chromatography Mass Spectrometry ◽  
Oxidative Aging ◽  
Before And After ◽  
Thermal Oxidative Aging ◽  
Kinetics Of

This paper study the migration characteristics and degradation kinetics of bisphenol A using TGA - gas chromatography - mass spectrometry and found that bisphenol A polycarbonate in the thermal oxidative aging conditions of 130 °C de-gradated to bisphenol A. At the range of 0 h to 120 h, the bisphenol A content of environmental hormones increased with time. When it reached 120 h, bisphenol A environmental hormone content decreased slightly with aging time. The content of bisphenol A reached 495mg/kg when the thermal oxidative aging time was 168 h, which was decreased compared to the content of 442mg/kg at 120 h. Polycarbonate thermal decomposition kinetics study showed that the thermal decomposition of polycarbonate can be divided into three phases. The first thermal decomposition occurred at the range of 415° C to 425 ° C, the polycarbonate end groups fracture of the second stage at 493.6°C , the main fracture of the main chain rearrangement and crosslinking, and the third stage at 598.7°C, the degradation of the chain continues to decompose and the decomposition of the crosslinked carbon precursor; thermal oxidation aging of polycarbonate decreased the heat stability and promote the thermal decomposition of polycarbonate. Comparing the oxidation induction period, thermal weight loss rate and activation energy of polycarbonate before and after thermal oxidative aging, it c found that the thermal stability of the hot oxygen aging of polycarbonate is reduced.

scholarly journals Unifloral Autumn Heather Honey from Indigenous Greek Erica manipuliflora Salisb.: SPME/GC-MS Characterization of the Volatile Fraction and Optimization of the Isolation Parameters

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2487
Author(s):  
Marinos Xagoraris ◽  
Foteini Chrysoulaki ◽  
Panagiota-Kyriaki Revelou ◽  
Eleftherios Alissandrakis ◽  
Petros A. Tarantilis ◽  
...  
Keyword(s):  
Solid Phase ◽  
Sample Volume ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Fraction ◽  
Volatile Components ◽  
Equilibration Time ◽  
Optimum Conditions ◽  
Organoleptic Characteristics ◽  
First Time

For long heather honey has been a special variety due to its unique organoleptic characteristics. This study aimed to characterize and optimize the isolation of the dominant volatile fraction of Greek autumn heather honey using solid-phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). The described approach pointed out 13 main volatile components more closely related to honey botanical origin, in terms of occurrence and relative abundance. These volatiles include phenolic compounds and norisoprenoids, with benzaldehyde, safranal and p-anisaldehyde present in higher amounts, while ethyl 4-methoxybenzoate is reported for the first time in honey. Then, an experimental design was developed based on five numeric factors and one categorical factor and evaluated the optimum conditions (temperature: 60 °C, equilibration time: 30 min extraction time: 15 min magnetic stirrer velocity: 100 rpm sample volume: 6 mL water: honey ratio: 1:3 (v/w)). Additionally, a validation test set reinforces the above methodology investigation. Honey is very complex and variable with respect to its volatile components given the high diversity of the floral source. As a result, customizing the isolation parameters for each honey is a good approach for streamlining the isolation volatile compounds. This study could provide a good basis for future recognition of monofloral autumn heather honey.

scholarly journals Chemical Characterization of the Lipophilic Fraction of Livistona Decipiens and Livistona Chinensis Fruit Pulps (Palmae) and Assessment of Their Anti-hyperlipidemic and Anti-ulcer Activities

2009 ◽  
Vol 4 (2) ◽  
pp. 1934578X0900400
Author(s):  
Hazem Kadry ◽  
Soha Shoala ◽  
Omayma El Gindi ◽  
Amany A. Sleem ◽  
Salwa Mosharrafa ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Chemical Characterization ◽  
Gas Chromatography Mass Spectrometry ◽  
Rat Stomach ◽  
Principal Fatty Acid ◽  
Palm Fruits ◽  
Livistona Chinensis ◽  
First Time ◽  
The Relationship

The oil of the dried pulps of Livistona decipiens and L. chinensis palm fruits have been studied for the first time by gas chromatography-mass spectrometry for their unsaponifiable matter (USM) and fatty acid composition (FAME). The anti-hyperlipidemic and anti-ulcer activities for both oils were also assayed. The principal fatty acid of L. decipiens pulp oil was oleic acid (53.4 %) and of L. chinensis pulp oil palmitic acid (47.4 %). In relation to anti-hyperlipidemic properties, the pulp oil of L. decipiens presented a better profile than that of L. chinensis, in comparison with the reference standard (simvastatin). In addition, both pulp oils showed high anti-ulcer activity using an indomethacin-induced ulceration technique in rat stomach. The relationship between the anti-hyperlipidemic, anti-ulcer and chemical composition of the pulp oils is also discussed.

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