Mechanism and kinetics of chlorpyrifos co-metabolism by using environment restoring microbes isolated from rhizosphere of horticultural crops under subtropics.

The indiscriminate use of organophosphate insecticide chlorpyrifos in agricultural crops causes significant soil and water pollution and poses a serious threat to the global community. In this study, a microbial consortium ERM C-1 containing bacterial strains Pseudomonas putida T7, Pseudomonas aeruginosa M2, Klebsiella pneumoniae M6, and a fungal strain Aspergillus terreus TF1 was developed for the effective degradation of chlorpyrifos. Results revealed that microbial strains were not only utilizing chlorpyrifos (500 mg L-1) but also coupled with plant growth-promoting characteristics and laccase production. PGP traits, that is, IAA (35.53, 45.53, 25.19, and 25.53 µg mL-1), HCN (19.85, 17.85, 12.18, and 9.85 µg mL-1), and ammonium (14.73, 16.73, 8.05, and 10.87 µg mL-1) production, and potassium (49.53, 66.72, 46.14, and 52.72 µg mL-1), phosphate (52.37, 63.89, 33.33, and 71.89 µg mL-1), and zinc (29.75, 49.75, 49.12, and 57.75 µg mL-1) solubilization tests were positive for microbial strains T7, M2, M6, and TF1, respectively. The laccase activity by ERM C-1 was estimated as 37.53, 57.16, and 87.57 enzyme U mL-1 after 5, 10, and 15 days of incubation, respectively. Chlorpyrifos degradation was associated with ERM C-1 and laccase activity, and the degree of enzyme activity was higher in the consortium than in individual strains. The biodegradation study with developed consortium ERM C-1 showed a decreased chlorpyrifos concentration from the 7th day of incubation (65.77% degradation) followed by complete disappearance (100% degradation) after the 30th day of incubation in the MS medium. First-order degradation kinetics with a linear model revealed a high k -day value and low t 1/2 value in ERM C-1. The results of HPLC and GC-MS analysis proved that consortium ERM C-1 was capable of completely removing chlorpyrifos by co-metabolism mechanism.

Role of whole-body vibration exposure and posture of dumper operators in musculoskeletal disorders: a case study in metalliferous mines.

Objectives. The combined role of whole-body vibration (WBV) exposure and awkward posture on musculoskeletal disorders (MSDs) experienced by dumper operators in two metalliferous mines in India was evaluated through a cross-sectional study. Methods. Frequency-weighted root mean square (rms) acceleration was used for WBV exposure assessment. Anthropometry and rapid upper limb assessment (RULA) were used for static and dynamic posture assessment, respectively. Prevalence of MSDs was assessed using the Nordic musculoskeletal questionnaire (NMQ). Logistic regression was used to assess the factors contributing to MSD problems. Results. The rms values revealed that the operators exceeded the lower limit of Standard No. ISO 2631-1:1997. The dynamic posture study revealed that the majority of dumper operators were taking awkward postures and 58-74% of them were subjected to high and medium levels of MSD risk. The adjusted odds ratio (7.96, 95% confidence interval [1.24, 41.35]) for the most awkward postures revealed WBV exposure as the significant risk factor for MSD problems among the operators. Conclusion. WBV exposure and posture of operators should be regularly monitored and corrective actions implemented to reduce their MSD problems. Ergonomic seat design based on the anthropometry of the operators should be assessed at the time of procuring new equipment.

Exploration of Klebsiella pneumoniae M6 for paclobutrazol degradation, plant growth attributes, and biocontrol action under subtropical ecosystem.

In recent times, injudicious use of paclobutrazol (PBZ) in mango orchards deteriorates the soil quality and fertility by persistence nature and causes a serious ecosystem imbalance. In this study, a new Klebsiella pneumoniae strain M6 (MW228061) was isolated from mango rhizosphere and characterized as a potent plant growth promoter, biocontrol, and PBZ degrading agent. The strain M6 efficiently utilizes PBZ as carbon, energy and nitrogen source and degrades up to 98.28% (50 mgL-1 initial conc.) of PBZ at 15th day of incubation in MS medium. In the soil system first order degradation kinetics and linear model suggested 4.5 days was the theoretical half-life (t1/2 value) of PBZ with strain M6. Box Behnken design (BBD) model of Response surface methodology (RSM) showed pH 7.0, 31°C temperature, and 2.0 ml inoculum size (8 x 109 CFU mL-1) was optimized condition for maximum PBZ degradation with strain M6. Plant growth promoting attributes such as Zn, K, PO4 solubilization IAA, HCN and NH3 production of strain M6 showed positive results and were assessed quantitatively. The relation between plant growth promotion and PBZ degradation was analyzed by heat map, principal component analysis (PCA) and, clustal correlation analysis (CCA). Strain M6 was also showing a significant biocontrol activity against pathogenic fungi such as Fusarium oxysporum (MTCC-284), Colletotrichum gloeosporioides (MTCC- 2190), Pythium aphanidermatum (MTCC- 1024), Tropical race 1 (TR -1), and Tropical race 4 (TR -4). Hence, results of the study suggested that strain M6 can be utilized as an effective bio-agent to restore degraded land affected by persistent use of paclobutrazol.

Mechanisms and kinetics for the degradation of paclobutrazol and biocontrol action of a novel Pseudomonas putida strain T7.

The present study explores biodegradation kinetics and process optimization of plant growth retardant from triazole group paclobutrazol (PBZ; C15H20ClN3O mol. wt. 293.79 g mol-1) in a batch experiment. A gram-negative rod-shaped bacterium T7 was isolated from PBZ applied agricultural field by enrichment technique and characterized as Pseudomonas putida strain T7. Strain was tested for PBZ biodegradation and plant growth-promoting characteristics. Results revealed that strain T7 utilizes PBZ as a carbon and energy source and showing degradation up to 98.30% on the 15th day. First-order degradation kinetics and a linear model were well fitted and showing a maximum t1/2 value on 9th day. Biodegradation optimization by Box Behnken design (BBD) of Response surface methodology (RSM) showed maximum degradation at pH 7.0, 31 °C temperature, and 2 mL inoculum size (8 × 109 CFU mL-1). The bacterium was also able to solubilize Zn, K, and PO4 and produced a copious amount of IAA, HCN, and Ammonia. The biocontrol activity against plant pathogens like Fusarium oxysporum (MTCC-284), Colletotrichum gloeosporioides (MTCC 2190), Pythium aphanidermatum (MTCC - 1024), Tropical race-1 (TR -1), and Tropical race - 4 (TR-4) showed the great antagonistic effect. Hence, this strain can be employed as an effective bio-agent for eco-friendly cleanup strategies and pathogen suppressive agents in paclobutrazol contaminated soil.

Influence of imidacloprid on bacterial community diversity of mango orchard soil assessed through 16S rRNA sequencing-based metagenomic analysis.

Imidacloprid, used against mango hopper, is a persistent insecticide in soil. Microbes have the ability to remove toxic pesticides from soil surface. Metagenomic is an approach for understanding the diversity and related metabolic activities in any environmental sample without culturing the microbes. Metagenomic analysis of mango orchard soil was carried out using 16S rRNA gene sequencing to understand the impact of imidacloprid on soil microbial population. In control and imidacloprid applied soil samples, representative sequences clustered were 0.142930 and 0.082320 million, respectively. At the kingdom level, 85 and 88 percent represented to bacteria, 2 and 1 percent to archaea, and 13 and 11 percent to unassigned for control and treated metagenomes, respectively. At phylum level, 16 and 17 percent of OTUs (operational taxonomic units) were assigned with Proteobacteria, while 13 and 11 percent of OTUs were unassigned in control and imidacloprid-treated samples, respectively. The other abundant phyla in both the samples were Planctomycetes, Bacteroidetes, and Actinobacteria. At class level, 9 and 11 percent of OTUs were assigned with Planctomycetia in control as well as imidacloprid-treated samples, respectively. A number of OTUs present in control and imidacloprid applied samples are 31,173 and 21,909, respectively, with 18,018 number of OTUs shared between the two samples. The genus Gemmata totally disappeared in imidacloprid applied soil, while those belonging to class Phycisphaerae, genus Prevotella and species copri were identified in imidacloprid treatment. Bacterial community transformation was evident from this study indicating possible microbial bioremediation of imidacloprid in mango orchard soil.

Dissipation kinetics and risk assessment of thiamethoxam and dimethoate in mango.

Thiamethoxam and dimethoate are two insecticides used to control hoppers and inflorescence midges in mango. Thiamethoxam (0.008 and 0.016%) and dimethoate (0.06 and 0.12%) were sprayed on Dashehari mango trees during the pre-mature stage of fruit (first week of May) to study their dissipation kinetics and risk assessment in mango fruit. Thiamethoxam dissipated in fruit from 1.93 and 3.71 mg kg(-1) after 2 h of spraying to 0.08 and 0.13 mg kg(-1) after 20 days of spraying at single and double doses, respectively. Its residue did not persist beyond 20 days in fruit. Dimethoate dissipated in fruit from 2.81 and 5.34 mg kg(-1) after 2 h of application to 0.12 and 0.19 mg kg(-1) after 10 days of application at single and double doses, respectively. No residue was detected in fruit beyond 10 days after its application. Both ready-to-harvest mature mango fruit and pulp (after 40 days of spraying) were free from any residues of these insecticides at both the concentration levels. The rate of dissipation of these insecticides followed first-order kinetics in fruit with residual half-lives of 4.0 to 4.5 days for thiamethoxam and 2 days for dimethoate. Based on their MRL values of 0.5 and 2.0 mg kg(-1) in mango, pre-harvest intervals of 7 and 11 days, and 6 and 7 days were suggested for thiamethoxam and dimethoate, respectively, after spraying at single and double doses. The theoretical maximum residue contribution (TMRC) values for both the insecticides, calculated for residues corresponding to each sampling date, were found to be below the maximum permissible intake (MPI) values on mango fruit (except for dimethoate double dose up to 3 days); hence, both thiamethoxam and dimethoate could be considered non-hazardous to consumers at the above doses and time intervals.

Persistence behavior of imidacloprid and carbosulfan in mango (Mangifera indica L.).

Imidacloprid was sprayed on mango cv. Dashehari at 0.3 mL L(-1) of water during pre-bloom stage with 6-8 cm panicle size (first week of March) to control hopper and carbosulfan was sprayed at 2.0 mL L(-1) of water in the trees of mango hybrid (H-1000) during fruit development stage (first week of May) to control leaf webber. Residues of both the insecticides were analysed in peel, pulp and fruit at different stages of fruit development and maturity. The initial residues of imidacloprid, after 30 days of spraying, were 1.21, 0.56 and 1.77 mg kg(-1) in peel, pulp and whole fruit, respectively. The residues persisted in peel for 60 days and in pulp for 50 days and dissipated with a half-life of 38 days. Mature Dashehari fruits at harvest (after 85 days of spraying) were free from imidacloprid residues. Carbosulfan in mango peel dissipated from 5.30 mg kg(-1) (after 1 h of spraying) to 0.05 mg kg(-1) at the time of harvest (after 45 days of spraying). Carbosulfan residue in pulp was very low (0.08 mg kg(-1)) after 1 h of spraying, which increased gradually to 0.90 mg kg(-1) after 10 days and finally came down to 0.04 mg kg(-1) after 26 days of spraying. The insecticide residue was not detected in the pulp at the time of harvest. The residues persisted in pulp for 26 days and in peel for 45 days and degraded with a half-life of 7 days. The dissipation of both imidacloprid and carbosulfan followed first order rate kinetics in whole fruit (peel + pulp). Therefore, the safe pre-harvest intervals were suggested to be 55 days for imidacloprid and 46 days for carbosulfan before consumption of mango fruits after spraying of these insecticides.

Relationship between job, lifestyle, age and occupational injuries.

BACKGROUND: Physical job demands (PJD), age, disability and lifestyle may influence the risk of occupational injury. AIM: To assess the relationships between PJD, lifestyle and injury in workers of various ages. METHODS: A total of 2888 randomly selected workers from northeastern France, aged >or=15, completed a postal questionnaire. The PJD score was defined as the total number of the following reported job demands: using pneumatic tools, other vibrating hand tools, hammers, machine tools or vibrating platforms and exposure to manual handling tasks, awkward postures, high pace of work, high physical workload, work at heights, work in adverse climates or exposure to noise, cold or heat. Data were analysed using logistic regression. RESULTS: Nine per cent of subjects reported an injury during the previous 2 years. The PJD score was related to the injury rate for workers aged >or=45: crude odds ratio (OR) 3.5 (95% confidence interval = 1.5-8.0) for PJD = 1, 5.0 (2.2-11.3) for PJD = 2-3 and 14.5 (6.5-32.2) for PJD >or=4, versus PJD = 0. Lower ORs were found for those aged <30 (1.4, 4.2 and 9.9, respectively) and 30-44 (1.5, 4.4 and 6.5, respectively). The differences between age groups remained when controlling for all factors studied. Obesity, smoking and musculoskeletal disorders were associated with injury risk in workers aged >or=45 (adjusted ORs 1.7-2.6). Smoking was also an injury risk factor for workers aged <30. CONCLUSIONS: PJD and lifestyle have a higher impact on injury rates among older workers than among younger ones. Injury prevention should address reducing PJD and improving relevant lifestyle factors, especially for older workers.

Dynamical structure factor and spin-density separation for a weakly interacting two-component Bose gas.

We show that spin-density separation in a Bose gas is not restricted to 1D but also occurs in higher dimensions. The ratio (alpha) of the intraspecies atom-atom interaction strength to the interspecies interaction strength strongly influences the dynamics of spin-density separation and the elementary excitations. The density wave is phononlike for all values of alpha. For alpha < 1, the spin wave is also phononlike. The spin waves have a quadratic dispersion in the alpha=1 coupling regime, while in the phase separated regime (alpha > 1) the spin waves are found to be damped. The dynamical structure factor reveals two distinct peaks corresponding to the density and spin waves for alpha < or =1. For alpha > 1 there is only one dynamical structure factor peak corresponding to the density wave.

Associations of job, living conditions and lifestyle with occupational injury in working population: a population-based study.

OBJECTIVES: To assess the roles of job demands, living conditions and lifestyle in occupational injury. METHODS: The sample included 2,888 workers, aged > or =15 years, randomly selected from the north-eastern France. The subjects completed a mailed questionnaire. Data were analyzed with adjusted odds ratios (ORa) computed with the logistic model. RESULTS: In total, 9.2% of workers had an injury during the previous 2 years. The high job demands: tasks at height, handling objects, pneumatic tools, other vibrating hand tools, work in adverse climate, physical workload, vibrating platform, machine tools, cold, heat, awkward posture, noise, hammer, and pace had crude odds ratios between 1.81 and 5.25 for injury. A strong exposure-response relationship was found between the cumulated job demands (CJD, defined by their number) and injury: OR 1.88 (95% CI 1.23-2.87) for CJD1, 4.39 (2.98-4.46) for CJD2-3, and 9.93 (6.70-14.7) for CJD > or = 4, versus CJD0. These ORs decreased to 1.68, 3.70, and 7.15 respectively, when adjusted for sex, age, and living conditions/lifestyle confounders; and to 1.54, 2.99, and 5.45 respectively when also adjusted for job category. The following factors had significant ORa: age <30 years (1.54, 1.12-2.12), male (1.64, 1.18-2.30), smoking (1.60, 1.22-2.10), musculoskeletal disorders (1.54, 1.17-2.04), and frequent drug use for fatigue (2.03, 1.17-3.53). The workmen, farmers/craftsmen/tradesmen, and foremen had a 5.7-8.7-fold while the clerks and technicians a 2.7-3.6-fold higher risk compared with upper class. The risk associated with CJD was twofold higher among the workers aged > or =40 or with frequent drug use for fatigue compared with the others. Obesity had ORa 2.05 (1.11-3.78) among the subjects aged > or =40, and excess alcohol use had ORa 2.44 (1.26-4.72) among those free of disease. CONCLUSIONS: This study identified a wide range of job demands and living conditions/lifestyle which predicted injury. Preventive measures should be conducted to reduce job demands and to help workers to be aware of the risk and to improve their living conditions/lifestyle.

Simultaneous estimation of tribenuron-methyl and its major metabolites by high-performance liquid chromatography.

A rapid reversed phase HPLC method was developed for the separation of tribenuron-methyl and its three major metabolites (methyl-2-aminosulphonyl benzoate, 4-methoxy-6-methyl-2-methylamino-1,3,5-triazine and saccharin) using RP-18 column and methanol-water (60:40, v/v) as mobile phase. The limit of detection of all the four compounds was 0.01 ppm.

Binding of 5,5-diphenylhydantoin with erythrocyte membrane: local lateral order parameter and strong interaction with phospholipid head groups.

We have studied the interaction of 5,5-diphenylhydantoin (5,5-dph), an anticonvulsant drug, with erythrocyte membrane lipids and proteins using IR spectroscopic technique. The local lateral order parameter, which is directly related to the lipid packing density, has been found to be elevated due to 5,5-dph binding. This increase has been accounted for on the basis of relaxation of local discontinuity in orientational order (defects). The transition towards an ordered structure is further supported by our experimental results which exhibit a decrease in the hydrocarbon chain mobility. The reorganization of the polar head groups due to 5,5-dph-lipid interaction leads to the absence of the bands at 1150 cm-1 (C-O stretch or C-O-C antisymmetric stretch) and 1085 cm-1 (C-O-P stretch or PO2- symmetric stretch). These bands are associated with the phospholipid head groups in erythrocyte membrane. Significant intensity changes in amide I (1650 cm-1) and amide II (1520 cm-1) have been explained using the concept of transition dipole moment coupling between C-N and N-H vibrational modes of amide II.