Metal induced non-metallothionein protein in earthworm: A new pathway for cadmium detoxification in chloragogenous tissue.

Earthworms neutralize toxic metals by a small (∼13 kDa) cysteine rich metal binding protein, metallothionein (MT). Although the rate of metal accumulation and MT expression does not correlate well, the reason behind such inconsistency has not yet been deciphered. The present investigation clearly demonstrates that expression of some non-MT metal induced proteins is responsible for such incongruity. Applying selective protein isolation techniques in fluorescence tagged cadmium exposed (135 mg/kg) earthworms we were able to purify a 150 kDa metal induced protein (MIP) among others. After 60 days of exposure cadmium accumulation in earthworm intestines was significant. Immunofluorescence staining followed by confocal microscopy exhibited that MIP accumulates ingested cadmium in the intestinal region and eventually deposits the metal in the chloragogenous tissue. We determined the N-terminal sequence of 15 amino acid residues and after bioinformatics analysis, it was concluded that MIP is most probably a glutamic acid rich, novel cadmium binding protein. To further validate the binding mechanism, we conducted paper chromatography and continuous variation experiments which evidenced that cadmium readily binds to glutamic acid. The present finding is the first in-vivo evidence of a non-metallothionein cadmium binding protein induced in the intestines of earthworm exposed to a cadmium rich environment.

Effect of dibenz(b,f)-1,4-oxazepine aerosol on the breathing pattern and respiratory variables by continuous recording and analysis in unanaesthetised mice.

A riot control agent has to be a sensory irritant of a reversible type without pulmonary irritation as the later can cause lung injury. The aim of the present study is to continuously record and analyse breathing pattern and respiratory variables of dibenz (b,f)-1,4-oxazepine (CR) in unanaesthetised mice during and after exposure. The lowest concentration of 0.65 mg/m3 did not produce any effect on the breathing pattern. As high as 500 fold increase (315.9 mg/m3) in the concentration was used and no mortality was observed. CR produced a concentration dependent sensory irritation, without pulmonary irritation or airflow obstruction, showing that it may not cause any lung injury. The sensory irritation was initiated within 5 min of exposure due to the activation of TRPA1 receptors of the upper respiratory tract. Immediate recovery of normal breath without sensory irritation was observed in all the concentrations except the highest concentration of 315.9 mg/m3. Corresponding to the sensory irritation there was concentration dependent respiratory depression. The 50 percent respiratory depression (RD50) in this experiment was 152 mg/m3 and the estimated threshold limit value for occupational exposure was 4.56 mg/m3. The present study shows that CR causes sensory irritation only which is completely recoverable.

Appraisal of lignocellusoic biomass degrading potential of three earthworm species using vermireactor mediated with spent mushroom substrate: Compost quality, crystallinity, and microbial community structural analysis.

Spent mushroom substrate (SMS) is a recalcitrant lignocellulosic waste. Recycling of SMS through composting has been reported; however, the process is lengthy due to its complex biochemical composition. Although vermitechnology is known for its high efficiency, it has rarely been applied to recycle SMS. In this study, the qualitative value of vermicomposted SMS mediated by three earthworm species (i.e., Eisenia fetida, Eudrilus eugeniae, and Perionyx excavatus) was evaluated on the basis of nutrient availability, microbial activity, phospholipid fatty acid (PLFA) profiles, and seed germination assays. Degradation profiles of the lignocellulosic substrate in the vermireactors were assessed by monitoring the changes in crystallinity and distribution of functional groups using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy, respectively. Total organic carbon decreased by 1.4-3.5 folds with approximately 2.1-2.4 folds increase in nitrogen and phosphorus availability in all vermibeds. Interestingly, pH declined in the Eisenia and Eudrilus systems but increased in the Perionyx-vermibeds. XRD-derived crystallinity index was reduced significantly by 1.37 folds in Perionyx-vermicompost with concurrent microbial enrichment. Further, profuse abundance of vital functional groups (CO, NH, and OH) was clearly observed in the vermicompost with Perionyx followed by that with Eisenia. Moreover, PLFA illustrated significant variations in fatty acid distributions and microbial communities of the three vermicomposting systems. The seed germination assay showed that the germination index and relative root-shoot vigor of Perionyx-vermicompost treated seeds were 1.05-1.30 times greater than those of Eisenia and Eudrilus vermicompost treated ones. The results suggest that SMS degradability was affected by the growth of a healthy microbial community through vermicomposting.

Mushrooms: from nutrition to mycoremediation.

Mushrooms are well known as important food items. The uses of mushrooms in the cuisine are manifolds and are being utilized for thousands of years in both Oriental and Occidental cultures. Medicinal properties of mushrooms show an immense potential as drugs for the treatment of various diseases as they are rich in a great variety of phytochemicals. In this review, we attempted to encompass the recent knowledge and scientific advancement about mushrooms and their utilization as food or curative properties, along with their natural ability to accumulate (heavy) metals/radionuclides, which leads to an important aspect of bioremediation. However, accumulation of heavy metals and radionuclides from natural or anthropogenic sources also involves potential nutritional hazards upon consumption. These hazards have been pointed out in this review incorporating a selection of the most recently published literature.

Common explosives (TNT, RDX, HMX) and their fate in the environment: Emphasizing bioremediation.

Explosive materials are energetic substances, when released into the environment, contaminate by posing toxic hazards to environment and biota. Throughout the world, soils are contaminated by such contaminants either due to manufacturing operations, military activities, conflicts of different levels, open burning/open detonation (OB/OD), dumping of munitions etc. Among different forms of chemical explosives, 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro- 1,3,5,7-tetrazocine (HMX) are most common. These explosives are highly toxic as USEPA has recommended restrictions for lifetime contact through drinking water. Although, there are several utilitarian aspects in anthropogenic activities, however, effective remediation of explosives is very important. This review article emphasizes the details of appropriate practices to ameliorate the contamination. Critical evaluation has also been made to encompass the recent knowledge and advancement about bioremediation and phytoremediation of explosives (especially TNT, RDX and HMX) along with the molecular mechanisms of biodegradation.

Ameliorating effect of S-2(ω-aminoalkylamino) alkylaryl sulfide (DRDE-07) on sulfur mustard analogue, 2-chloroethyl ethyl sulfide-induced oxidative stress and inflammation.

Sulfur mustard (SM; 2,2'-dichloro diethyl sulfide), an alkylating chemical warfare agent, poses a major threat in both military conflict and chemical terrorism situations. 2-chloroethyl ethyl sulfide (CEES) is a monofunctional analogue of SM, frequently used in laboratory settings, therefore increasing chances of its exposure. S-2(ω-aminoalkylamino) alkylaryl sulfide (DRDE-07) is an analogue of amifostine reported to have protective effects against SM but its effect on CEES is largely unexplored. Therefore, this study was planned to explore the effects of DRDE-07 against CEES-induced toxicity. 0.75 LD50 (1068 mg/kg) of CEES was exposed percutaneously in the presence or absence of DRDE-07 (249 mg/kg p.o.) which is given prophylactically (before 30 minute) to male mice. Animals were sacrificed on 24 h, 7th day and 14th day of CEES exposure, and tissues were collected to study oxidative stress and inflammatory markers. CEES exposure depleted intracellular GSH level and activities of GSH-linked enzymes (GR, GPx and GST) which play a major role in GSH metabolism. CEES exposure augmented lipid peroxidation indicating severe oxidative stress. It also initiated inflammation causing an increase in proinflammatory (IL1-α, IL1-ß, IL-6, TNF-α and IFN-ϒ) and corresponding decrease in anti-inflammatory cytokines (IL-4 and IL-10). This was also accompanied by neutrophils infiltration indicated by higher than normal myeloperoxidase (MPO) levels. DRDE-07 efficiently reduced the oxidative stress and also facilitated to resolve inflammatory alterations. This study thus evaluated the beneficial role of DRDE-07 in ameliorating the deleterious effects of CEES and can be potentially used against SM/CEES poisoning.

Effects of 28 days silicon dioxide aerosol exposure on respiratory parameters, blood biochemical variables and lung histopathology in rats.

Inhalation toxicity of silicon dioxide aerosol (150, 300 mg/m(3)) daily over a period of 28 days was carried out in rats. The changes in respiratory variables during the period of exposure were monitored using a computer programme that recognizes the modifications of the breathing pattern. Exposure to the aerosol caused a time dependent decrease in tidal volume, with an increase in respiratory frequency compared to the control. Biochemical variables and histopathological observation were noted at 28th day following the start of exposure. Biochemical markers of silica induced lung injury like plasma alkaline phosphatase, lactate dehydrogenase and angiotensine converting enzyme activities increased in a concentration dependent manner compared to control. Increase in the plasma enzymatic activities indicates endothelial lung damage, increased lung membrane permeability. Histopathological observation of the lungs confirmed concentration dependent granulomatous inflammation, fibrosis and proteinacious degeneration. Aggregates of mononuclear cells with entrapped silica particles circumscribed by fibroblast were observed in 300 mg/m(3) silica aerosol exposed group at higher magnification. Decrease in tidal volume and increase in respiratory frequency might be due to the thickening of the alveolar wall leading to a decreased alveolar volume and lowered elasticity of the lung tissue. The trends in histological and biochemical data are in conformity with the respiratory data in the present study. This study reports for the first time, the changes in respiratory variables during silica aerosol exposure over a period of 28 days.

Evaluation of oleoresin capsicum of Capsicum frutescenes var. Nagahari containing various percentages of capsaicinoids following inhalation as an active ingredient for tear gas munitions.

Comparative efficacy as peripheral sensory irritant, oral and inhalation exposure studies were carried out on oleoresin capsicum (OC) of Capsicum frutescence var. Nagahari containing various percentages of capsaicinoids and two synthetic isomers of capsaicin in Swiss albino male mouse model to come up with a suitable active ingredient from natural source for tear gas munitions. The compounds screened were OC having varying percentages of capsaicinoids (20, 40 and 80%, respectively) and synthetic isomers (E and Z) of capsaicin (8-methyl-N-vanillyl-6-nonenamide). Mice were exposed to pyrotechnically generated smoke of the compounds in an all glass static exposure chamber for 15 min to determine acute inhalation toxicity (LC50) and quantitative sensory irritation potential (RD50). Acute oral median lethal dose (LD50) was also evaluated. Safety index of tear gas (SITG), a ratio of lethal concentration 50% (LC50) and the concentration which depresses respiration by 50% (RD50) due to peripheral sensory irritation is also proposed. The compound having highest SITG is considered as the most suitable to be used for tear gas munitions. The study revealed that oleoresin capsicum containing 40% capsaicinoids had the highest SITG among the compounds studied. The oral dosage versus mortality pattern of some compounds did not follow a true dose-response curve (DRC); however, following inhalation, all the compounds followed DRC. It was concluded that oleoresin capsicum (40% capsaicinoids) may be considered as the most suitable and environmental friendly compound from natural source to be used as an active ingredient for tear gas munitions.

Designing of mouse model: a new approach for studying sulphur mustard-induced skin lesions.

This study was planned to design a mouse model for studying sulphur mustard (SM)-induced skin injury. SM was applied dermally at dose of 5 or 10 mg kg(-1) in polyethyleneglycol-300 (PEG-300) or dimethylsulphoxide (DMSO) or acetone once. The changes in body weight, organ body weight indices (OBWI) and haematological and oxidative stress parameters were investigated over a period of 3-7 days and supported by histopathological observations. Exposure to SM in PEG-300 or DMSO resulted in a significant depletion in body weight, OBWI, hepatic glutathione (GSH) and elevation in hepatic lipid peroxidation, without affecting the blood GSH and hepatic oxidised glutathione (GSSG) levels. Interestingly, no aforesaid change was observed after dermal application of SM diluted in acetone. These biochemical changes were supported by the histological observations, which revealed pronounced toxic effect and damage to liver, kidney and spleen after dermal application of SM diluted in PEG-300 or DMSO. The skin showed similar microscopic changes after dermal application of SM in all the three diluents, however; the severity of lesions was found to be time and dose dependent. It can be concluded that dermal exposure of SM diluted in acetone can be used to mimic SM-induced skin toxicity without systemic toxicity in a mouse model.

Comparative effects of pyrolytic products of fiber reinforced plastic and wood shavings on the respiratory variables in mice.

Comparative inhalation toxicity studies of pyrolytic products (smoke) from synthetic polymer, fiberglass reinforced plastic (FRP) and teak wood shavings were carried out in male Swiss albino mice. The breathing pattern and the respiratory variables were monitored using a computer program that recognizes the modifications of the respiratory pattern. Exposure to the smoke from both the polymers caused a concentration dependent decrease in normal breathing and an increase in sensory irritation measure. The acute lethal concentration 50 values for a 15 min static inhalation exposure to the smoke from FRP and teak wood shavings were found to be > 200.00 and 62.99 g/m(3), respectively. Hence the inhalation toxicity of smoke from FRP sample on a mass basis is approximately one-third that of the smoke from teak wood. The concentration of smoke causing 50% respiratory depression of the exposed animals were found to be 6.877 and 0.106 g/m(3) for FRP and teak wood samples, respectively. Thus the sensory irritancy of the smoke from FRP sample is approximately 65 times lesser than the smoke from teak wood. The higher sensory irritancy potential of wood smoke as compared to FRP smoke may be caused by a greater number of submicron particles (size range of 2 micron and less) and greater percentage of gases present in wood smoke as compared to FRP smoke. Thus in case of accidental fires, synthetic polymers like FRP may be a safer choice for structural parts and interiors than the natural wood.

Comparative effects of insect repellent N,N-diethylbenzamide, N,N-diethylphenylacetamide, and N,N-diethyl-3- methylbenzamide aerosols on the breathing pattern and respiratory variables in mice.

Comparative inhalation toxicity studies of aerosols of insect repellents N,N-diethylbenzamide (DEB), N,N-diethylphenylacetamide (DEPA), and N,N-diethyl-3-methylbenzamide (DEET) were carried out in mice. The respiratory pattern was monitored using a computer program that recognizes the modifications of the breathing pattern. Exposure to the aerosols caused a dose-dependent decrease in normal breath, with an increase in airway obstruction. All the three insect "sensilla irritants" showed no significant mammalian sensory irritation. The acute LC(50) value for a 4-h exposure of DEB, DEPA, and DEET aerosols in male mice was found to be >2.5 g/m(3), 1714 mg/m(3), and 1369 mg/m(3), respectively. Irreversible depression in respiratory frequency was observed after exposure to DEB aerosol at a concentration of 277 mg/m(3) and above, which did not revert back to normal level even after aerosol exposure was stopped. At a concentration of 156 mg/m(3) of DEB, no respiratory depression was observed. DEPA and DEET caused no depression in respiratory frequency up to a concentration 1292 and 950 mg/m(3), respectively. Hence the two insect repellents DEET and DEPA do not cause any harmful effect to the respiratory parameters in acute exposure, showing that they are more suitable chemicals to be used as insect repellents as compared to DEB.

Abrin induced oxidative stress mediated DNA damage in human leukemic cells and its reversal by N-acetylcysteine.

Abrin is a plant glycoprotein toxin, classified as ribosome inactivating protein (RIP) due to its property of damaging ribosomes in an irreversible manner. Many RIPs have direct DNA damaging activity. The objective of the present study was to evaluate the oxidative stress and DNA damaging potential of abrin in U937 human myeloleukemic cells. Cells were treated with abrin at IC50 of 8 ng/ml for 24h. Abrin induced a time dependent increase in reactive oxygen species and levels of antioxidant enzymes. There was significant depletion of reduced glutathione levels. DNA damage was assessed by comet assay in terms of percent head DNA, tail DNA, tail length and Olive tail moment. DNA damage was more pronounced at 4 and 8h at IC50 concentration. Abrin at 4, 8, 16 and 32 ng/ml concentration induced significant DNA damage at 4h. There was time dependent increase in levels of 8-OHdG in abrin treated cells indicating the oxidative stress mediated DNA damage. N-Acetylcysteine pretreatment at 10nM for 1h, considerably reversed the abrin induced DNA damage at 16 and 32 ng/ml. Our results clearly show oxidative DNA damage potential of abrin at low concentration.

Hepatoprotective efficacy of certain flavonoids against microcystin induced toxicity in mice.

Toxic cyanobacteria (blue-green algae) water blooms have become a serious problem in several industrialized areas of the world. Microcystin-LR (MC-LR) is a cyanobacterial heptapeptide that represents acute and chronic hazards to animal and human health. Identification of suitable chemprotectants against microcystin is essential considering human health hazards. In the present study, we have evaluated the protective efficacy of three flavanoids namely quercetin (200 mg/kg), silybin (400 mg/kg), and morin (400 mg/kg)] pretreatment against microcystin toxicity (0.75 LD(50), 57.5 microg/kg) in mice. Various biochemical variables were measured to study the recovery profile of protected animals at 1- and 3-days post-toxin treatment. The serum alanine amino transferase (ALT) shows 17-fold increase in MC-LR treated animals compared with control group at 1 day. The silybin and quercetin group showed a decrease in level of ALT compared with MC-LR group but still higher than control group. No significant protection was observed with aspartate aminotransaminase (AST) and lactate dehydrogenase (LDH) levels in flavanoid-treated groups at 1-day post-treatment. But at 3 days, the serum levels of AST and ALT were normalized to control values, but the serum LDH levels were still significantly higher than the control group. No significant changes were observed in glutathione peroxidase and reduced glutathione levels at both 1- and 3-day postexposure. The catalase activity shows a significant decrease in quercetin-treated animals at 3-day postexposure. The protein phosphatase was significantly inhibited in MC-LR group compared to control. The silybin pretreated group showed recovery after 1 day. At 3 days, the PPAse activity was reversed to control values in all the flavanoid-treated groups. Immunoblotting analysis showed microcystin-PPAse adduct in liver tissues of toxin-treated as well as flavanoid-treated mice even after 3 days. The results of this study show that flavanoids, quercetin, silybin, and morin could reverse the hepatotoxic effects of MC-LR in vivo.