Role of Gordonia sp JAAS1 in biodegradation of chlorpyrifos and its hydrolysing metabolite 3,5,6-trichloro-2-pyridinol.

UNLABELLED: Paddy field soil with prior exposure to chlorpyrifos was chosen for the biodegradation of the pesticide by employing bacteria with special emphasis given to actinomycetes. Actinomycetes are organisms predominantly known for their bioactive compounds, but there is dearth of work pertaining to their role in bioremediation. So this work was carried out to screen for actinomycetes and assess their potential in degradation of the pesticide. Actinobacterial strains were isolated from paddy field soil, with capabilities to degrade chlorpyrifos and its major metabolite 3,5,6-trichloro-2-pyridinol (TCP). Two strains were successfully isolated among which one strain was efficient and was able to tolerate high concentrations of chlorpyrifos. This strain was selected for further investigation; it was identified as Gordonia sp based on 16S rRNA analysis and designated as Gordonia sp JAAS1. The actinobacterial strain was able to degrade 110 mg l(-1) of chlorpyrifos within 24 h incubation, and TCP was found to accumulate in the culture medium. However, after 72 h of incubation, TCP was degraded, and finally, diethylthiophosphoric acid (DETP) was obtained. SIGNIFICANCE AND IMPACT OF THE STUDY: Biodegradation of chlorpyrifos results in the formation of an antimicrobial compound 3,5,6-trichloro-2-pyridinol (TCP). It is more mobile compared with the parent molecule due to its higher water solubility thus, causing widespread contamination and has antimicrobial property. Therefore, biodegradation of TCP, the major metabolite of chlorpyrifos, is crucial as if left to accumulate, it will kill all the beneficial microbes in the soil. In this study, Streptomyces belonging to genus Gordonia sp JAAS1 strain capable of degrading not only chlorpyrifos but also TCP was observed. This is a first report pertaining to biodegradation of chlorpyrifos and its metabolite TCP from Gordonia genus. The ability to degrade chlorpyrifos and its metabolite TCP makes this strain a useful candidate for the remediation of contaminated sites.

Crystal structures of two 4H-chromene derivatives: 2-amino-3-cyano-4-(3,4-di-chloro-phen-yl)-7-hy-droxy-4H-benzo[1,2-b]pyran 1,4-dioxane monosolvate and 2-amino-3-cyano-4-(2,6-di-chloro-phen-yl)-7-hy-droxy-4H-benzo[1,2-b]pyran.

In the title compounds, C16H9Cl2N2O2·C4H8O2 and C16H9Cl2N2O2, the bicyclic 4H-chromene cores are nearly planar with maximum deviations of 0.081 (2) and 0.087 (2) Å. In both structures, the chromene derivative mol-ecules are linked into centrosymmetric dimers by pairs of N-H⋯O hydrogen bonds, forming R2 2 (16) motifs. These dimers are further linked in the 3,4-di-chloro-phenyl derivative by N-H⋯N hydrogen bonds into double layers parallel to (100) and in the 2,6-di-chloro-phenyl derivative by O-H⋯N hydrogen bonds into ribbons along the [10] direction. In the 3,4-di-chloro-phenyl derivative, the 1,4-dioxane solvent mol-ecules are connected to the chromene mol-ecules via O-H⋯O hydrogen bonds.

Crystal structure, DFT and Hirshfeld surface analysis of 2-amino-4-(2-chloro-phen-yl)-7-hy-droxy-4H-benzo[1,2-b]pyran-3-carbo-nitrile.

The benzo-pyran ring of the title com-pound, C16H11ClN2O2, is planar [maximum deviation = 0.079 (2) Å] and is almost perpendicular to the chloro-phenyl ring [dihedral angle = 86.85 (6)°]. In the crystal, N-H⋯O, O-H⋯N, C-H⋯O and C-H⋯Cl hydrogen bonds form inter- and intra-molecular inter-actions. The DFT/B3LYP/6-311G(d,p) method was used to determine the HOMO-LUMO energy levels. The mol-ecular electrostatic potential surfaces were investigated by Hirshfeld surface analysis and two-dimensional fingerprint plots were used to analyse the inter-molecular inter-actions in the mol-ecule.

Characterization of an Insecticidal Protein from Withania somnifera Against Lepidopteran and Hemipteran Pest.

Lectins are carbohydrate-binding proteins with wide array of functions including plant defense against pathogens and insect pests. In the present study, a putative mannose-binding lectin (WsMBP1) of 1124 bp was isolated from leaves of Withania somnifera. The gene was expressed in E. coli, and the recombinant WsMBP1 with a predicted molecular weight of 31 kDa was tested for its insecticidal properties against Hyblaea puera (Lepidoptera: Hyblaeidae) and Probergrothius sanguinolens (Hemiptera: Pyrrhocoridae). Delay in growth and metamorphosis, decreased larval body mass and increased mortality was recorded in recombinant WsMBP1-fed larvae. Histological studies on the midgut of lectin-treated insects showed disrupted and diffused secretory cells surrounding the gut lumen in larvae of H. puera and P. sanguinolens, implicating its role in disruption of the digestive process and nutrient assimilation in the studied insect pests. The present study indicates that WsMBP1 can act as a potential gene resource in future transformation programs for incorporating insect pest tolerance in susceptible plant genotypes.