Phosphamidon, methylparathion and dichlorvos impact on tissue oxidative metabolism in penaeid prawn, Metapenaeus monoceros

Changes in oxidative metabolism of hepatopancreas and muscle tissues of penaeid prawn, Metapenaeus monoceros was studied, following its exposure to selected organophosphorous insecticides phosphamidon, dichlorovos and methylparathion. The OPI are found to inhibit the activity levels of acetylcholinesterase, succinate dehydrogenase, isocitrate dehydrogenase, pyruvate dehydrogenase, lactate dehydrogenase and cytochrome-c-oxidase and cause accumulation of acetylcholine in the hepatopancreas and muscle tissues. These changes in the activity levels of selected oxidative enzymes during insecticide exposure in these tissues of prawn indicates the shift in the metabolic emphasis from aerobic to anaerobic conditions and is interpreted as a functional adaptation to insecticide induced metabolic stress. These observed changes at cellular level pave way for successful survival of prawns in insecticide polluted environ.     

Tissue glycolytic potentials of penaeid prawn, Metapenaeus monoceros during methylparathion, carbaryl and aldrin exposure.

Changes in midgut gland and muscle tissue glycolytic potentials of penaeid prawn, Metapenaeus monoceros following exposure to methylparathion, carbaryl and aldrin were studied. A decrease in total carbohydrates, glycogen and pyruvate and an increase in lactate levels were observed. An increase in phosphorylase 'a' and aldolase activity levels suggested increased formation of trioses during selected insecticide toxicity. The decrease in the lactate dehydrogenase activity levels and an increase in the lactate content indicative of reduced mobilization of pyruvate into the citric acid cycle. During selected insecticide exposure, the prawn tissues adopting some sort of regulatory pathways such as enhanced glycolysis and a shift of metabolic emphasis from aerobiosis to anaerobiosis. All the above mentioned changes were more pronounced in the midgut gland compared to muscle tissue. The per cent decrease or increase are more under aldrin exposure followed by carbaryl and methylparathion exposure. The selected insecticides in the present investigation, though belongs to different representative groups, but appears to be neurotoxic leading to disturbances in the carbohydrate catabolism.     

Toxic impact of phosphamidon on protein degradation in phasic and tonic muscles of marine prawn, Penaeus indicus (H. Milne Edwards).

Levels of various protein fractions, (sarcoplasmic, myosin, actin, non-collagen and collagen) and the rate of their degradation by proteases were studied in phasic and tonic muscles of marine prawn, Penaeus indicus following acute (2 d) and chronic (15 d) exposure to sublethal concentration of phosphamidon. During exposure, greater decrease in sarcoplasmic protein fraction was observed in phasic muscle as compared to other myofibrillar proteins. But the sarcoplasmic protein content showed an elevation in tonic muscle. The changes in protein fractions were more pronounced during acute exposure than chronic exposure both in phasic and tonic muscles. These changes were correlated with the elevation of the acidic, neutral and basic protease activities during acute and chronic exposure. Free amino acids were increased during acute exposure, while they showed a significant decrease during chronic exposure in both the muscles. These results indicate that protein metabolism in both phasic and tonic muscles was significantly altered following phosphamidon exposure. These differential responses observed at acute and chronic exposure indicate the operation of compensatory mechanisms to mitigate the phosphamidon toxic stress.     

Recovery of carbaryl inhibited AChE in penaeid prawn, Metapenaeus monoceros

The acetylcholinesterase activity in selected tissues of prawn, Metapenaeus monoceros showed a significant inhibition during commercial (CgC) and technical (TgC) grade carbaryl exposure. The rate of inhibition of AChE in nervous and non-nervous tissues is more under CgC over TgC exposure, suggests the involvement of emulsifier system for easy penetration of CgC molecule, which is absent in TgC. A progressive recovery of AChE activity from TgC and CgC induced inhibition was in the tissues within 10 days after the transfer of prawns to toxicant free water i.e., recovery or reclamation period. From the study, it has been observed that the inhibition of AChE activity is still persists evenafter 10 days of reclamation period, gives the idea of carbaryl accumulation at the cellular level or the reclamation period is not sufficient for the restoration of normalcy of AChE activity.     

Inhibition and recovery of selected target enzyme activities in tissues of penaeid prawn, Metapenaeus monoceros (Fabricius), exposed to different insecticides.

The target enzymes, acetylcholinesterase (for phosphamidon and carbaryl) and Mg2+ ATPase (for DDT and fenvalerate) have been assayed during exposure and reclamation of these insecticides in M. monoceros. Toxicity of these insecticides are in the order: fenvalerate greater than DDT greater than carbaryl greater than phosphamidon. Reclamation studies show that fenvalerate is rapidly degradable while DDT is slowly degradable. It is suggested that pyrethroid, organophosphate and carbamate insecticides may be preferred over organochlorine compounds in farm operations.     

Impact of methylparathion and malathion on cholinergic and non-cholinergic enzyme systems of penaeid prawn, Metapenaeus monoceros

The nervous tissue AChE, BUChE and glutaminase activity levels were significantly inhibited, whereas glutamine synthetase activity, acetylcholine and glutamine contents were increased significantly following the sublethal exposure of prawn, Metapenaeus, monoceros to methylparathion and malathion. During OPI exposure ammoniagenesis was triggered by increased deamination of purines and oxidative deamination of glutamate. This results in the hyperammonemia. As a consequence of hyperammonemia, the OPI exposed prawn tissue have adopted the suitable mechanisms to detoxity the ammonia by enhancing the synthesis of urea and glutamine. From the study, it has been observed that 10 days of reclamation period is not enough but the prawn nervous tissue showed efficient mechanisms for the detoxification or biodegradation of OPI molecules, which will pave way for the successful survival prawns.     

Methylparathion, carbaryl and aldrin impact on nitrogen metabolism of prawn, Penaeus indicus

Changes in hepatopancreas, muscle and gill tissue nitrogen metabolic profiles were studied in a penaeid prawn, Penaeus indicus, following its exposure to sublethal concentrations of methylparathion, carbaryl and aldrin. In all the insecticide exposed prawn tissues, Ammonia levels were significantly increased and a shift in the nitrogen metabolism towards the synthesis of urea and glutamine was observed. Inhibition of glutamate oxidation to ammonia and alpha-ketoglutarate by glutamate dehydrogenase suggests a mechanism whereby hyperammonemia is reduced by minimizing the addition of further ammonia to the already existing elevated ammonia pool. Increased alanine and aspartate aminotransferases demonstrates the onset of gluconeogenesis. Mechanisms to detoxify the ammonia by enhancing the synthesis of urea and glutamine at the cellular level was observed in the selected tissues pave way for the survivability of prawns in insecticide polluted environs.     

Electrophoretic separation of protein pattern in different tissues of four marine penaeid prawns in relation to sex

The protein patterns of gill, midgut gland and abdominal muscle tissues of four different marine penaeid prawn species: Metapenaeus affinis, Metapenaeus monoceros, Parapenaeopsis hardwickii and Parapenaeopsis stylifera were investigated qualitatively by polyacrylamid gel disc electrophoresis in relation to sex. All tissues showed their own peculiar pattern of protein fractions. The possible significance of these differences is discussed.This investigation was supported by I.C.A.R., New Delhi, through a project on Reprod. Endocr. Edible prawns     

Subacute physiological stress induced by phosphamidon on carbohydrate metabolism in midgut gland of prawn, Penaeus indicus

Midgut gland carbohydrate metabolism of penaeid prawn, Penaeus indicus was studied on acute and acclimation to sublethal concentration of phosphamidon. The midgut gland tissue of acclimated prawn showed inhibited glycolysis with an onset of gluconeogenesis. In general acclimation to sublethal concentration resulted in the elevation of the synthetic phase of midgut gland carbohydrate metabolism.     

Assessment of phosphamidon-induced apoptosis in human peripheral blood mononuclear cells: protective effects of N-acetylcysteine and curcumin

The molecular mechanism for noncholinergic toxicity of phosphamidon, an extensively used organophosphate pesticide, is still not clear. The aim of the present study is to find the possible molecular mechanism of this pesticide to induce apoptosis and the role of different drugs for attenuation of such effects. Human peripheral blood mononuclear cells (PBMC) were incubated with increasing concentrations of phosphamidon (0-20 μM) for 6-24 h. The MTT assay reveals that phosphamidon induces cytotoxicity in a dose-dependent manner. Cellular glutathione (GSH) is depleted in a dose-dependent manner from 55% to 70% at concentrations between 10 and 20 μM. The percentage of cells that bind to Annexin-V, which is a representative of cells either undergoing apoptosis or necrosis during 24 h incubation, increases in a dose-dependent manner. Above 5 μM, significant necrosis of cells was observed. DNA fragmentation assay revealed that at low concentration of phosphamidon (1 μM), no appreciable change in DNA fragmentation was seen; however, distinct fragmentation was observed beyond 2.5 μM. Phosphamidon was found to cause significant depletion of GSH, which correlates well with the percentage of cells undergoing apoptosis. An increasing trend in levels of cytochrome c was observed with increasing concentration of phosphamidon, indicating that the apoptotic effect of phosphamidon is mediated through cytochrome c release. Coadministration of the antioxidants N-acetylcysteine and curcumin attenuated phosphamidon-induced apoptosis. This further supports our hypothesis that oxidative stress, as indicated by GSH depletion, results in the induction of apoptosis by release of cytochrome c.     

家蚕耐氟性差异的细胞化学研究

对不同蚕品种的耐氟性、ACPase的氟敏感性、蚕品种耐氟性机理的研究表明,在供试蚕品种中以浙农1号的耐氟性最强,杭 8的耐氟性最弱;家蚕Bombyx mori血淋巴ACPase活性与蚕品种的耐氟性无明显关系;氟对蚕的血淋巴和中肠组织细胞的ACPase活性都有抑制作用,并随着氟添食浓度的增加ACPase活性降低,但超过一定浓度的氟添食,血淋巴ACPase活性反而有一个回升的过程,这个转折点出现可能的浓度及回升的幅度与蚕品种的耐氟性有关;细胞化学研究发现此转折点的出现是由于高浓度氟引起细胞结构的破坏而导致蚕体组织细胞内的ACPase大量向血腔释放的结果;氟敏感性蚕品种杭 8在很低氟量添食即可引起中肠组织细胞的ACPase大量向血腔释放,使血淋巴中的ACPase活性大幅度上升,随后ACPase活性受到完全的抑制;耐氟性较强的蚕品种浙农1号则在较高的氟含量添食时才向血腔释放ACPase,且血淋巴中ACPase增高的幅度小,在很高的氟量添食时全面抑制中肠ACPase活性。氟对不同品种ACPase活性影响的差异被认为是家蚕品种耐氟性差异机理之一。     

Influence of some environmental variables on the ascorbic acid status of striped mullet, Mugil cephalus Linn., tissues. III. Effects of exposure to oil

Exposure to water-soluble fractions (WSF) of a crude and two fuel oils altered the ascorbic acid (AsA) content of several striped mullet, Mugil cephalus , tissues. Exposure to sublethal concentrations of all three WSFs caused a depletion of AsA reserves in brain, gill, kidney and liver tissues, but not in muscle. There was a marked decline in AsA stores in kidney and gill tissues after only one day of exposure to WSFs of both crude and fuel oils. Liver AsA concentrations were significantly depleted after one week of oil exposure. Brain AsA content was only significantly depleted during chronic exposure to the highest oil concentration (20% WSF). A dose-dependent depletion of AsA reserves in the liver but not in the other tissues was observed one week after a single exposure to 2–20% WSFs of a No. 2 fuel oil. Exposure to 20% WSF of the No. 2 fuel oil caused a 47% decrease in liver AsA content one week later. Hepatic concentrations were still significantly depleted after 15 days, but had returned to control levels 20 days after the initial exposure. The data suggest that the depletion of tissue AsA reserves in fish inhabiting oil-contaminated environments could be sufficient on occasions to lead to AsA deficiency.     

Development of tolerance to opiates and opioid peptides in organotypic cultures of mouse spinal cord

Following chronic exposure of organotypic explants of mouse spinal cord with attached dorsal root ganglia (DRG) to low levels of morphine (1 μM) for 2–3 days (at 35°C), the initial opiate-depressant effects on sensory-evoked dorsal-horn network responses disappeared and characteristic dorsal cord responses could then be evoked by DRG stimuli in the presence of morphine — even after acute increases in concentration (up to 100-fold). Similar tolerance developed after chronic exposure of cord-DRG explants to low concentrations (10 nM) of an enkephalin analog (Sandoz FK 33-824). The latter cultures showed cross-tolerance to met-enkephalin and opiates; dorsal cord responses could still be evoked even after acute exposure to high levels of morphine. Morphine-tolerant cultures also showed cross-tolerance to met-enkephalin and to the Sandoz opioid peptide (FK 33-824). The tolerant state did not develop if the cultures were incubated at lower temperature, ca. 20°C, during exposure to 1 μM morphine for as long as 7 days. The data indicate that a temperature-dependent metabolic change occurs in these neurons after chronic exposure to morphine at 35°C leading to a sustained decrease in sensitivity to opiate-depressant effects. Enhanced dorsal-horn responses in tolerant cultures suggested development of “dependence” as well as tolerance to opiates in these isolated cord-DRG tissues.     

The trophotaenial placenta of a viviparous goodeid fish. III: Protein uptake by trophotaeniae, the embryonic component

Protein uptake and degradation by trophotaenial cells of the viviparous goodeid fish Ameca splendens were studied colorimetrically and ultrastructurally using horseradish peroxidase (HRP) as a tracer and acid (ACPase) and alkaline (ALPase) phosphatase cytochemistry. Trophotaeniae are ribbon-like external projections of the embryonic gut that are equivalent to greatly hypertrophied intestinal villi. During gestation within the ovarian lumen, trophotaeniae are directly apposed to the internal ovarian epithelium (IOE) where they establish a placental association between the developing embryo and maternal organism. Trophotaenial absorptive cells possess an ALPase reactive brush border, an endocytotic apparatus, and ACPase reactive standing lysosomes. Ultrastructural studies of protein uptake indicate that cells of the trophotaenial epithelium take up HRP by micropinocytosis and degrade it within lysosomes. Initially (from 1.5-10 min), HRP is taken up in vitro at 22 degrees C at the apical cell surface and passes via endocytotic vesicles into an apical canalicular system. From 1.5 to 10 min exposure, HRP passes passes from the apical canalicular system to a series of small collecting vesicles. After 10 min, HRP is detected within large ACPase reactive supranuclear lysosomes. Three hours after an initial 1 h exposure to HRP, most peroxidase activity within supranuclear lysosomes is no longer detected. Presence of Golgi complexes, residual bodies, and secretory granules in the infranuclear cytoplasm suggest that products of protein uptake and hydrolysis are discharged across basal and lateral cell surfaces and into the trophotaenial circulation. Trophotaeniae of embryos incubated in vitro in HRP-saline take up HRP at an initial rate of 13.5 ng HRP/mg trophotaenial protein/min. The system becomes saturated after 3 h. Trophotaeniae incubated at 4 degrees C show little or no uptake. In trophotaeniae continuously pulsed with HRP for 1 h, then incubated in HRP-free saline, levels of absorbed peroxidase declined at a rate of 0.5 ng/mg trophotaenial protein/min. HRP does not appear to enter the embryo via extra-trophotaenial routes. These findings are consistent with the putative role of trophotaeniae as the embryonic component of the functional placenta of goodeid fishes. Trophotaenial uptake of maternal nutrients accounts for a massive (15,000%) increase in embryonic dry weight during gestation.     

Chronic uranium exposure dose-dependently induces glutathione in rats without any nephrotoxicity

Abstract

Uranium is a heavy metal naturally found in the earth's crust that can contaminate the general public population when ingested. The acute effect and notably the uranium nephrotoxicity are well known but knowledge about the effect of chronic uranium exposure is less clear. In a dose-response study we sought to determine if a chronic exposure to uranium is toxic to the kidneys and the liver, and what the anti-oxidative system plays in these effects. Rats were contaminated for 3 or 9 months by uranium in drinking water at different concentrations (0, 1, 40, 120, 400, or 600 mg/L). Uranium tissue content in the liver, kidneys, and bones was linear and proportional to uranium intake after 3 and 9 months of contamination; it reached 6 μg per gram of kidney tissues for the highest uranium level in drinking water. Nevertheless, no histological lesions of the kidney were observed, nor any modification of kidney biomarkers such as creatinine or KIM-1. After 9 months of contamination at and above the 120-mg/L concentration of uranium, lipid peroxidation levels decreased in plasma, liver, and kidneys. Glutathione concentration increased in the liver for the 600-mg/L group, in the kidney it increased dose dependently, up to 10-fold, after 9 months of contamination. Conversely, chronic uranium exposure irregularly modified gene expression of antioxidant enzymes and activities in the liver and kidneys. In conclusion, chronic uranium exposure did not induce nephrotoxic effects under our experimental conditions, but instead reinforced the antioxidant system, especially by increasing glutathione levels in the kidneys.     

Effects of chronic dietary exposure to a low-dose of Malathion, Aroclor-1254 and 3-methylcholanthrene on three biomarkers in male mice

The aim of this research was to examine the applicability of some chronic toxicological tests in the determination of exposure to xenobiotics present in concentrations below No Observed Adverse Effect Level (NOAEL) and below the detection limit of analytical instruments. In the present experiment tested chemicals (Malathion, Aroclor-1254 and 3-methylcholanthrene (3-MC)) were mixed with wheat grains and given to male mice as feed over a period of 12 months. 7-ethoxyresorufin-O-deethylase (EROD) activity with the 3-MC and Aroclor-1254 treatments reached the peak at 9th month of exposure (26.7 and 42.4 pmol?1 mg(prot)-?1, respectively), while malathion did not have significant influence. Glutathione (GSH) level depletion was highest after three months of exposure. Unexpectedly, acetylcholinesterase (AChE) activity increased after treatment with malathion, an organophosphorous insecticide. In conclusion, low-level concentrations chronically administered exert certain effects on the levels of selected enzymes, e.g. biomarkers.     

Introducing Baculovirus oryctes Huger into Oryctes monoceros Oliv. populations in Tanzania

A follow-up of a Baculovirus oryctes release into the population of Oryctes monoceros in coconut plantations in Tanzania has been made to clarify important points which were not fully considered in an earlier publication. The low recovery of virus-infected field-collected beetles (29%) suggested that the release of B. oryctes virus was not a suitable method for the control of O. monoceros. The relatively dry conditions in the coconut growing areas were partly contributory since the virus is non-occluded. No significant and sustainable reduction in frond damage was obtained after the virus had established itself in the natural O. monoceros population. The status of O. monoceros as a serious pest of coconut is also revised since the beetle affects young plantations more than older plantations and control methods can be directed at picking up feeding insects by hooking and disposal of breeding sites.     

In vivo humoral and cellular reactions, and fate of injected bacteria Aeromonas hydrophila in freshwater prawn Macrobrachium rosenbergii

Live non-opsonized and opsonized Aeromonas hydrophila were injected into juveniles of freshwater prawn Macrobrachium rosenbergii to study the cells involved in phagocytosis, distribution of bacteria, cellular reactions and clearance of both forms of bacteria from the system. The bacteria were rapidly distributed to various tissues viz., gills, heart, hepatopancreas within 1h, and the tissues revealed haemocytic nodule formation after 3 h of injection. There was rapid clearance of both the forms of bacteria from the circulation. However, clearance efficiency was significantly (P < 0.05) faster in the case of opsonized bacteria at 12 h after injection. Similarly, the nodule formation, that was prominent in cardiac musculature, was rapidly eliminated from the tissues of the group injected with opsonized bacteria as compared to non-opsonized bacteria injected group, thus confirming the existence of opsonic factors in haemolymph of this prawn. In another experiment, various dose levels of bacteria were injected intramuscularly into prawns and haemolymph was collected after 1, 6, 24, 72 h and 7 days of injection to study various immune parameters. Although, no major alterations in the total and differential haemocyte counts were observed in bacteria injected prawns compared to control, there was a significant decline in phenoloxidase activity in the highest dose bacteria injected group at the earlier phase and a rise in agglutinin levels at the later phase of the experimental period in the higher dose groups.     

Acute effects of glyphosate herbicide on metabolic and enzymatic parameters of silver catfish (Rhamdia quelen)

Silver catfish (Rhamdia quelen; Teleostei) were exposed to commercial formulation Roundup, a glyphosate herbicide: 0 (control), 0.2 or 0.4 mg/L for 96 h. Fish exposed to glyphosate showed an increase in hepatic glycogen, but a reduction in muscle glycogen at both concentrations tested. Glucose decreased in liver and increased in muscle of fish at both herbicide concentrations. Glyphosate exposure increased lactate levels in liver and white muscle at both concentrations. Protein levels increased in liver and decreased in white muscle while levels of ammonia in both tissues increased in fish at both glyphosate concentrations. Specific AChE activity was reduced in brain after treatments, no changes were observed in muscle tissue. Catalase activity in liver did not change during of exposure. Fish exposed to glyphosate demonstrated increased TBARS production in muscle tissue at both concentrations tested. For both glyphosate concentrations tested brain showed a reduction of TBARS after 96 h of exposure. The present results showed that in 96 h, glyphosate changed AChE activity, metabolic parameters and TBARS production. The parameters measured can be used as herbicide toxicity indicators considering environmentally relevant concentration.     

Histophysiology of polysaccharide and lipid reserves in various tissues of Littorina littorea exposed to sublethal concentrations of cadmium

1. Sublethal exposure to cadmium causes glycogen depletion in connective tissues of the mantle, kidney folds, and digestive gland-gonad complex. Glycogen levels are lower at higher environmental concentrations of metal and at longer exposure times.2. Simultaneously with glycogen level reduction in reserve tissues, higher levels of glycogen than in control specimens have been detected in the digestive gland of cadmium exposed winkles. Phosphoglucomutase activity has been detected in kidney, connective tissues, and intestine, but not in digestive tubules. This suggests glycogen mobilisation through digestive tubule epithelia.3. Phosphoglucomutase activity in gills is associated with glycogen level increases in blood vessels and in distal portion of gill lamellae after proximal epithelium disruption.4. Lipid contents of the studied organs are only decreased when glycogen levels are largely reduced. Lipase activity has been demonstrated in digestive tubule, kidney and gill epithelia, but not in connective tissues. It is concluded that lipidic store is intracellular while the polysaccharidic one is organismic.5. Sublethal concentrations of cadmium do not cause impairment of phosphoglucomutase and lipase activities: enzymatic activity is well correlated with reserve consumption, demonstrable activity being lost only after substrate (glycogen or lipid) depletion.