Toxicity and bioremediation of pesticides in agricultural soil

Pesticides are one of the persistent organic pollutants which are of concern due to their occurrence in various ecosystems. In nature, the pesticide residues are subjected to physical, chemical and biochemical degradation process, but because of its high stability and water solubility, the pesticide residues persist in the environment. Moreover, the prevailing environmental conditions like the soil characteristics also contribute for their persistence. Bioremediation is one of the options for the removal of pesticides from environment. One important uncertainty associated with the implementation of bioremediation is the low bioavailability of some of the pesticides in the heterogeneous subsurface environment. Bioavailability of a compound depends on numerous factors within the cells of microorganism like the transportation of susbstrate across cell membrane, enzymatic reactions, biosurfactant production etc. as well as environment conditions such as pH, temperature, availability of electron acceptor etc. Pesticides like dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), Endosulfan, benzene hexa chloride (BHC), Atrazine etc. are such ubiquitous compounds which persist in soil and sediments due to less bioavailability. The half life of such less bioavailable pesticides ranges from 100 to 200 days. Most of these residues get adsorbed to soil particles and thereby becomes unavailable to microbes. In this review, an attempt has been made to present a brief idea on ‘major limitations in pesticide biodegradation in soil’ highlighting a few studies.     

The C-terminal end of parainfluenza virus 5 NP protein is important for virus-like particle production and M-NP protein interaction

Enveloped virus particles are formed by budding from infected-cell membranes. For paramyxoviruses, viral matrix (M) proteins are key drivers of virus assembly and budding. However, other paramyxovirus proteins, including glycoproteins, nucleocapsid (NP or N) proteins, and C proteins, are also important for particle formation in some cases. To investigate the role of NP protein in parainfluenza virus 5 (PIV5) particle formation, NP protein truncation and substitution mutants were analyzed. Alterations near the C-terminal end of NP protein completely disrupted its virus-like particle (VLP) production function and significantly impaired M-NP protein interaction. Recombinant viruses with altered NP proteins were generated, and these viruses acquired second-site mutations. Recombinant viruses propagated in Vero cells acquired mutations that mainly affected components of the viral polymerase, while recombinant viruses propagated in MDBK cells acquired mutations that mainly affected the viral M protein. Two of the Vero-propagated viruses acquired the same mutation, V/P(S157F), found previously to be responsible for elevated viral gene expression induced by a well-characterized variant of PIV5, P/V-CPI(-). Vero-propagated viruses caused elevated viral protein synthesis and spread rapidly through infected monolayers by direct cell-cell fusion, bypassing the need to bud infectious virions. Both Vero- and MDBK-propagated viruses exhibited infectivity defects and altered polypeptide composition, consistent with poor incorporation of viral ribonucleoprotein complexes (RNPs) into budding virions. Second-site mutations affecting M protein restored interaction with altered NP proteins in some cases and improved VLP production. These results suggest that multiple avenues are available to paramyxoviruses for overcoming defects in M-NP protein interaction.     

Quantitative proteomic profiling identifies new renal targets of copper(II)‐selective chelation in the reversal of diabetic nephropathy in rats

This study aimed to identify new diabetic nephropathy (DN)‐related proteins and renal targets of the copper(II)‐selective chelator, triethylenetetramine (TETA) in streptozotocin‐diabetic rats. We used the recently developed iTRAQ? technology to compare renal protein profiles among non‐diabetic, diabetic, and TETA‐treated diabetic rats. In diabetic kidneys, tubulointerstitial nephritis antigen (TINag), voltage‐dependent anion‐selective channel (VDAC) 1, and VDAC2 were up‐regulated in parallel with alterations in expression of proteins with functions in oxidative stress and oxidative phosphorylation (OxPhos) pathways. By contrast, mitochondrial HSP 60, Cu/Zn‐superoxide dismutase, glutathione S‐transferase α3 and aquaporin‐1 were down‐regulated in diabetic kidneys. Following TETA treatment, levels of D ‐amino acid oxidase‐1, epoxide hydrolase‐1, aquaporin‐1, and a number of mitochondrial proteins were normalized, with concomitant amelioration of albuminuria. Changes in levels of TINag, collagen VIα1, actinin 4α, apoptosis‐inducing factor 1, cytochrome C, histone H3, VDAC1, and aquaporin‐1 were confirmed by Western blotting or immunohistochemistry. Changes in expression of proteins related to tubulointerstitial function, podocyte structure, and mitochondrial apoptosis are implicated in the mechanism of DN and their reversal by TETA. These findings are consistent with the hypothesis that this new experimental therapy may be useful for treatment of DN.     

Fluidization, resolidification, and reorientation of the endothelial cell in response to slow tidal stretches

Mechanical stretch plays an important role in regulating shape and orientation of the vascular endothelial cell. This morphological response to stretch is basic to angiogenesis, neovascularization, and vascular homeostasis, but mechanism remains unclear. To elucidate mechanisms, we used cell mapping rheometry to measure traction forces in primary human umbilical vein endothelial cells subjected to periodic uniaxial stretches. Onset of periodic stretch of 10% strain amplitude caused a fluidization response typified by attenuation of traction forces almost to zero. As periodic stretch continued, the prompt fluidization response was followed by a slow resolidification response typified by recovery of the traction forces, but now aligned along the axis perpendicular to the imposed stretch. Reorientation of the cell body lagged reorientation of the traction forces, however. Together, these observations demonstrate that cellular reorientation in response to periodic stretch is preceded by traction attenuation by means of cytoskeletal fluidization and subsequent traction recovery transverse to the stretch direction by means of cytoskeletal resolidification.     

Comparative Virulence Genotyping and Antimicrobial Susceptibility Profiling of Environmental and Clinical <Emphasis Type="Italic">Salmonella</Emphasis><Emphasis Type="Italic">enterica</Emphasis> from Cochin,India

Salmonella enterica serotype Newport is an important cause of non-typhoidal salmonellosis, a clinically less severe infection than typhoid fever caused by S. enterica serotype Typhi. In this investigation, the virulence genotypes of S. enterica Newport isolated from a backwater environment were compared with Salmonella Typhi from clinical cases in the same region where salmonellosis is endemic. Genotyping was done by PCR screening for virulence markers associated with Salmonella pathogenicity islands (SPIs) and plasmids. The virulence genes associated with SPIs I–VI were detected in 95–100% of all the isolates, while the viaB locus representing SPI-7 was detectable in 66 and 73% of the environmental and clinical isolates, respectively. A significant number of Salmonella Newport lacked virulence genes shdA and sopE compared to S. Typhi. All S. Typhi and S. Newport isolates lacked large plasmid-borne virulence genes spvR and pefA. Further investigations into the antimicrobial resistance of S. Newport revealed multiple drug resistance to ampicillin, amoxicillin/clavulanic acid, trimethorprim-sulfamethoxazole, chloramphenicol, tetracycline, cephalothin, and cephalexin. In comparison, S. Typhi were susceptible to all clinically relevant antimicrobials. The results of this study will help in understanding the spread of virulence genotypes and antibiotic resistance in S. Newport in the region of study.     

Highly sensitive lanthanide complex as a probe for l-kynurenine: A cancer biomarker

A lanthanide complex based on europium (Eu) and chelidamic acid was synthesized (Eu–CHE) and characterized. The complex Eu–CHE exhibited intense luminescence at 615 nm under excitation at 300 nm and was further investigated for highly sensitive turn-off detection of l -kynurenine (l -kyn), a cancer biomarker. The probe detected l -kyn linearly from 6 nM to 0.2 μM with a limit of detection and limit of quantification of 1.37 and 4.57 nM, respectively. The probe was investigated for selectivity towards l -kyn among co-existing amino acids and further extended for detecting l -kyn from human serum and urine samples. A low-cost paper strip-based sensing platform was also developed for the visual detection of l -kyn.     

Utilization of sugarcane bagasse cellulose for producing cellulose acetates: Novel use of residual hemicellulose as plasticizer

Sugarcane bagasse was fractionated to cellulose, hemicellulose and lignin by a proprietary steam explosion process, followed by downstream purifications, developed in our laboratory. The fractionated cellulose contained ～94% cellulose, about ～5% hemicellulose, traces of lignin (～0.2%), and ～1% ash. The cellulose was acetylated under heterogeneous conditions to obtain cellulose acetates. These were extensively characterized using FTIR, TGA, DSC, GPC, HPIC, WAXRD, and viscometry. The novel feature of this study was the utilization of the hemicellulose content (5%) of bagasse cellulose as an internal plasticizer. Through kinetic experimentation, we have demonstrated that the residual hemicellulose need not be considered as an impurity; rather it can be used in acetylated form as a plasticizer as well as a biodegradable additive for cellulose acetates made from slightly impure cellulose produced from non-wood origin. Our results therefore show how lignocellulosic agricultural wastes can be utilized to produce high value plastics.     

Illuminating the molecular basis of diabetic arteriopathy: A proteomic comparison of aortic tissue from diabetic and healthy rats

Arterial disease is a major diabetic complication, yet the component molecular mechanisms of diabetic arteriopathy remain poorly understood. In order to identify major proteins/pathways implicated in diabetic arteriopathy, we studied the effect of 16‐wk untreated streptozotocin‐induced diabetes on the rat aortic proteome. Specific protein levels in isolated aortas were compared in six discrete, pair‐wise (streptozotocin‐diabetic and non‐diabetic age‐matched controls) experiments in which individual proteins were identified and quantified by iTRAQ combined with LC‐MS/MS. A total of 398 unique non‐redundant proteins were identified in at least one experiment and 208 were detected in three or more. Between‐group comparisons revealed significant changes or trends towards changes in relative abundance of 51 proteins (25 increased, 26 decreased). Differences in levels of selected proteins were supported by Western blotting and/or enzyme assays. The most prominent diabetes‐associated changes were in groups of proteins linked to oxidative stress responses and the structure/function of myofibrils and microfilaments. Indexes of mitochondrial content were measurably lower in aortic tissue from diabetic animals. Functional cluster analysis also showed decreased levels of glycolytic enzymes and mitochondrial electron transport system‐complex components. These findings newly implicate several proteins/functional pathways in the pathogenesis of arteriosclerosis/diabetic arteriopathy.