Primary Gill Lamellae Research Articles

Histopathological alterations in the vital organs of Indian major carp Labeo rohita exposed to monosodium glutamate (MSG)

BackgroundMonosodium glutamate (MSG E621) is one of the most popular flavouring agents of modern times and is widely used in many commercially packed food and even in house hold cooking. Previous studies revealed that excessive intake of MSG in diet causes obesity, metabolic defects, nephrotoxicity, neurotoxicity and hepatotoxicity in rats, but no reports are available in the literature about the ecotoxicological assessment of MSG by using fishes as a bioindicators. Since fishes are important consumer in aquatic food chain and directly linked with human health status, the present study was aimed to investigate the impact of MSG in freshwater fish Labeo rohita by using histological biomarkers.ResultsNinety-six h-LC50 of MSG to Labeo rohita was determined (1.5 g/L), and fish exposed to sub-lethal concentration of MSG (1/10th of 96 h-LC50 concentration of MSG (150 mg/L)) showed distinguished behavioural changes like erratic movement, loss of appetite and excessive mucous secretion all over the body as an adaptive syndrome to avoid the direct exposure to MSG in the medium. Histopathological analysis clearly depicts severe damages in the vital organs of fish. In gills, epithelial necrosis, hypertrophy, hyperplasia, primary and secondary gill lamellae degeneration, oedema, fusion of adjacent secondary lamellae and rupture of gill epithelium were observed. The intensity of tissue damage was increased as the exposure period was extended. The liver displayed vein congestion, vacuole formation, degeneration in parenchymal cells and bile stagnation, whereas MSG-treated kidney tissue showed high interstitial inflammation. Among the vital organs gill and liver displayed the highest histopathological alterations.ConclusionsThe present study clearly demonstrated that MSG is toxic to fish and able to cause significant damages in the vital organs as the exposure period was extended. Since the studies on the toxicity of MSG to fish are rare, the present investigation may contribute to the scarce literature on sub-lethal toxicity of MSG to freshwater fishes.

Effects of chlorpyrifos on histopathological biomarkers of the freshwater teleost Oreochromis niloticus

Abstract An attempt was made to evaluate histopathological changes in the gills, liver, and kidney tissues of the freshwater teleost Oreochromis niloticus as biomarkers of chlorpyrifos toxicity. An experiment was conducted in glass aquaria with O. niloticus exposed for 28 days to sub-lethal concentrations of chlorpyrifos of 0.0 µg L−1 (control), 10 µg L−1, and 20 µg L−1. Chlorpyrifos caused distortions of the primary gill lamellae structure, the curling of secondary lamellae, desquamation, and epithelial hyperplasia on secondary gill filaments. Hepatocyte vacuolation and nuclear membrane necrosis were found in the liver. Additionally, the shrinkage of the glomeruli, thickening of Bowman’s capsule, glomerular and tubular necrosis, intracytoplasmic vacuoles, and hyaline degeneration in the renal tubule were seen in the kidney of O. niloticus exposed to chlorpyrifos. No remarkable lesions were observed in the control group. The severity of lesions in the fish tissues was assessed using the standard semi-quantitative grading system. The degree of histopathological lesions in various fish tissues was found to increase with chlorpyrifos concentrations. Histopathological lesions appeared to be good biomarkers of chlorpyrifos toxicity.

Occurrence of Multispecies Myxozoan Parasite Infestation by Genus <i>Thelohanellus</i> Kudo, 1933 in a Group of <i>Labeo rohita </i>(Hamilton, 1822)

We describe two Thelohanellus Kudo spp. namely, T. bifurcata (34.94x 8.9μm) on gills and T. caudatus (13x8.9μm) on the caudal and dorsal fins, found infecting Labeo rohita (Hamilton, 1822) fingerlings in a wet lab facility of West Bengal India. The L. rohita fingerlings having spores on fins and gills were segregated and gross pathology was observed for one month. It was done to characterise the morphology of mature spores and to examine the histopathology of infected gills. There were 5-6 white cysts (1-2 mm in length) on the gill filament that were mostly persistent during the one-month study period and infected fish (12.5% prevalent) were listless, anorexic, and emaciated before eventually all of them perished. Spores of 4- 7 mm size in 1-4 numbers were found on caudal and dorsal fins which were visible for two weeks before it gets mature and released, whereas infected fish (20%) were active and underwent normal growth. Additionally, it was discovered that 5% of fingerlings had cysts on their gills and fins. The distal tip of the primary gill lamellae is where the gill epithelium ruptures, releasing the spores. The histological inspection of the infected gill clearly demonstrates infective sporoplasm entry, presporogonic stage, plasmodial maturation, and release of spores. Within a month, it was discovered that 100% of the fingerlings with infected gills died. This is because the plasmodial spores on primary gill filaments damage the structural framework of the gill filament and cause epithelial and vascular cell displacement. Our comparative analysis with previous studies support that orders and families of the parasites are strongly correlated with Thellohanellus Kudo sp: a pathogenic strain of T. bifurcata and a non-pathogenic strain of T. caudatus infecting L. rohita. The spore-forming stages of the gill-damaging T. bifurcata (entry, pre-sporogonic, and sporogonic) are extremely pathogenic to fish fingerlings and cause significant damage to gill tissue

Gills of Molly Fish: A Potential Role in Neuro-Immune Interaction

This study identified the cellular compositions of the gills in molly fish and their role in immunity using light-, electron- microscopy, and immunohistochemistry. The molly fish gills consisted of four holobranchs spaced between five branchial slits. Each hemibranch carried many fine primary and secondary gill lamellae. The gill arch was a curved cartilaginous structure, from which radiated the bony supports of the primary lamellae. The gill arch contained the afferent and efferent brachial arteries. The gill arch was covered by epidermal tissue rich with mucous cells. The primary lamella had a central cartilaginous support and efferent and afferent arterioles and was covered with pavement cells (PVC), salt-secreting chloride cells, and pale-staining mucous cells. These chloride cells contained abundant mitochondria and tubulovesicular system and are involved in ionic transport with a potential role in detoxification. The surface of the secondary lamellae (site of gaseous exchange) consisted of overlapping or interdigitating PVC supported and separated by pillar cells. Other cells were found within the gill epithelium and interstitial connective tissues, including lymphocytes, macrophages, monocytes, telocytes, stem cells, astrocytes, and neuroepithelial cells. The immunohistochemical analysis revealed that APG-5, iNOS-2, IL-1β, NF-κB, and TGF-B showed positive immunoreactivity in macrophages. The epithelium of the primary gill lamellae contained positive-GFAP astrocytes and S100 protein—chloride cells. The stem cells expressed SOX9, myostatin, and Nrf2. Neuroendocrine cells expressed S100 protein. In conclusion, the current work suggests that the gills of molly fish are multifunctional organs and are involved in immune reactions.

Toxic effects of Parthenium hysterophorus on Muscles of freshwater fish Labeo rohita. (Vikhar)

The present study is conducted and assessed the toxicity of Parthenium hysterophorus is on locally available fresh water fish. The present study deals with to determine histological effects on fresh water fish, Labeo rohita. The fishes were collected from nearby water body and brought to the laboratory for determination of histological parameters up to 96hr. period. The muscles of fish exposed lethal concentration for different time exposure (24hrs. 48hrs. 72hrs. and 96hrs.) showed lesion, inflammation, pigment and necrosis of primary and secondary gill lamellae during low concentration while, increasing concentration for different time exposure showed necrosis, malignancy and cellular degeneration were seen at later time of exposure.

Digestive enzymes (amylase and invertase) analysis and histopathological changes in Oreochromis mossambicus treated with tricyclazole (75%) fungicide

Despite being efficient against rice blast fungal diseases when applied to agricultural fields, tricyclazole 75% fungicide has a variety of drawbacks that outweigh its benefits for the aquatic environment. Shortterm exposure to a sublethal dose of tricyclazole, fish O. mossambicus displayed altered digestive enzymes (amylase and invertase) as well as histological abnormalities in tissue organs like the skin, muscle, gills, liver, intestine, and brain tissues. The activity of amylase and invertase was found to decreasing and increasing in various concentrations. Histopathological changes on exposure to tricyclazole fungicides was found to increase in its pathological lesions of the tissue organs studied skin, muscle, gills, liver, intestine, and brain tissues of O. mossambicus noticed with necrosis, vacuolar degeneration, fusion and atrophy of the primary and secondary gill lamellae, degeneration of the cytoplasm in hepatocytes, atrophy, formation of vacuoles, rupture in blood vessels, damage in the dermis, concentrated melanophores, damaged blood vessels, and enlarged muscle fibers with increasing concentrations. Enzymatic alterations and pathological lesions in the tissue of O. mossambicus exposed to a toxicant at a sub-lethal concentration are a functional response of organisms that offers information on the nature of the toxicant. Hence, in the present study, in order to evaluate the environmental/aquatic pollution under experimental settings, an evaluation of the fish’s histological alterations and enzyme levels was carried out. In conclusion, fish are among the most susceptible aquatic species to harmful compounds; buildup of the fungicide in the fish may cause pathological problems that spread to people through the food chain.

Toxicological effects of the textile industrial effluent to an Indian freshwater fish, Clarias batrachus

In this study, the histological effects of textile industrial effluent in the freshwater fish, Clarias batrachus was studied after 10, 20, and 30 days period of exposure. The 24, 48, 72, and 96 hours LC50 values were found to be 58.476, 53.231, 47.253, and 37.429% respectively. During the experiment, the treated fishes showed abnormal behaviors like erratic swimming, hyper-excitation, rapid opercular movement, and thick mucus covering which indicated the toxicity of the effluent. The observed changes in the gills were epithelial hyperplasia with lamellar fusion, necrosis, vacuolar degeneration, and atrophy of primary and secondary gill lamellae. On the other hand, the liver showed the formation of the number of vacuoles, enlargement of nuclei of some cells, degeneration of cytoplasm in hepatocytes, atrophy, a rupture in blood vessels, and disposition of hepatic cords. The kidney also showed abnormalities like degeneration of proximal and distal convoluted tubule, vacuolation of renal interstitial tissue, necrosis, cellular hypertrophy, and granular cytoplasm.

Study of parasitic effect of Argulus sp. on Indian major carps in pond culture

The current investigation was undertaken to study the parasitic effects of Argulus sp. on Indian major carps. Only symptomatic and moribund samples of diseased fishes comprised of fingerlings and adults of Labeo rohita, Catla catla and Cirrhinus mrigala were collected for experiments. The affected fishes showed weight loss, retarded growth, restlessness, erratic swimming behaviour and loss of appetite. The skin showed abnormally pigmented while gills, kidney, liver and spleen of the affected fishes were pale in colour. The most significant histopathological lesions in the gills were the secondary lamellar hyperplasia, haemorrhages in the tips of the primary lamellae and fusion of both secondary and primary gill lamellae. Skin showed epidermis was lost but the epidermal cells in the vicinity of the sites of attachment were hyperplastic, muscular layer showed degenerative and necrotic. Kidney showed multifocal enlargement of glomeruli, glomerular tufts in many places shrunken, fragmented and necrosed, in renal tubules vacuolar degeneration. Fingerlings and adults of rohu were found highly susceptible to this disease than other IMC.

A practical guide to unbiased quantitative morphological analyses of the gills of rainbow trout (Oncorhynchus mykiss) in ecotoxicological studies.

Rainbow trout (Oncorhynchus mykiss) are frequently used as experimental animals in ecotoxicological studies, in which they are experimentally exposed to defined concentrations of test substances, such as heavy metals, pesticides, or pharmaceuticals. Following exposure to a broad variety of aquatic pollutants, early morphologically detectable toxic effects often manifest in alterations of the gills. Suitable methods for an accurate and unbiased quantitative characterization of the type and the extent of morphological gill alterations are therefore essential prerequisites for recognition, objective evaluation and comparison of the severity of gill lesions. The aim of the present guidelines is to provide practicable, standardized and detailed protocols for the application of unbiased quantitative stereological analyses of relevant morphological parameters of the gills of rainbow trout. These gill parameters inter alia include the total volume of the primary and secondary gill lamellae, the surface area of the secondary gill lamellae epithelium (i.e., the respiratory surface) and the thickness of the diffusion barrier. The featured protocols are adapted to fish of frequently used body size classes (300–2000 g). They include well-established, conventional sampling methods, probes and test systems for unbiased quantitative stereological analyses of light- and electron microscopic 2-D gill sections, as well as the application of modern 3-D light sheet fluorescence microscopy (LSFM) of optically cleared gill samples as an innovative, fast and efficient quantitative morphological analysis approach. The methods shown here provide a basis for standardized and representative state-of-the-art quantitative morphological analyses of trout gills, ensuring the unbiasedness and reproducibility, as well as the intra- and inter-study comparability of analyses results. Their broad implementation will therefore significantly contribute to the reliable identification of no observed effect concentration (NOEC) limits in ecotoxicological studies and, moreover, to limit the number of experimental animals by reduction of unnecessary repetition of experiments.

First Evidence of Carp Edema Virus Infection of Koi Cyprinus carpio in Chiang Mai Province, Thailand.

The presence of carp edema virus (CEV) was confirmed in imported ornamental koi in Chiang Mai province, Thailand. The koi showed lethargy, loss of swimming activity, were lying at the bottom of the pond, and gasping at the water’s surface. Some clinical signs such as skin hemorrhages and ulcers, swelling of the primary gill lamella, and necrosis of gill tissue, presented. Clinical examination showed co-infection by opportunistic pathogens including Dactylogyrus sp., Gyrodactylus sp. and Saprolegnia sp. on the skin and gills. Histopathologically, the gill of infected fish showed severe necrosis of epithelial cells and infiltrating of eosinophilic granular cells. Electron microscope examination detected few numbers of virions were present in the cytoplasm of gill tissue which showed an electron dense core with surface membranes worn by surface globular units. Molecular detection of CEV DNA from gill samples of fish was performed by polymerase chain reaction (PCR) and confirmed by nested-PCR. Phylogenetic analyses revealed that CEV isolate had 99.8% homology with the CEV isolated from South Korea (KY946715) and Germany (KY550420), and was assigned to genogroup IIa. In conclusion, this report confirmed the presence of CEV infection of koi Cyprinus carpio in Chiang Mai province, Thailand using pathological and molecular approaches.

Disease Progression in Lake Trout (Salvelinus namaycush) Experimentally Infected With Epizootic Epitheliotropic Disease Virus (Salmonid Herpesvirus-3).

Epizootic epitheliotropic disease virus (salmonid herpesvirus-3; EEDV) is responsible for the death of millions of hatchery-raised lake trout (Salvelinus namaycush) in the Laurentian Great Lakes Basin. However, little is known about its biology, pathology, tropism, and host interactions. In this study, the presence and disease progression of EEDV were evaluated following exposure of naïve juvenile lake trout to EEDV via bath immersion under controlled laboratory conditions (n = 84 infected; n = 44 control). Individual tissues (n = 10 per fish), collected over 6 weeks, were analyzed for viral load by quantitative polymerase chain reaction, gross and histopathologic changes, and virus cellular targets using in situ hybridization. Skin, fin, and ocular tissues were the earliest viral targets and yielded the highest viral loads throughout the course of infection. Early gross lesions included exophthalmia, ocular hemorrhage, fin congestion, and hyperemia of visceral blood vessels. Advanced disease was characterized by multifocal to coalescing erosions and ulcerations of the skin, and congestion of visceral organs. Microscopically, there was cellular degeneration and necrosis in the epidermis and spleen, and lymphohistiocytic perivasculitis of the dermis, omentum, and the epicardium. EEDV DNA was first detected by in situ hybridization in epithelial cells of the epidermis, with subsequent labeling in the epithelial lining of primary and secondary gill lamellae. During advanced disease, EEDV was detected in endothelial and dendritic cells as well as blood monocytes. This study characterized EEDV tissue tropism and associated pathologic features, to guide research aimed at understanding EEDV disease ecology and improving strategies for disease control.

Pathological effects of Cichlidogyrus philander Douëllou, 1993 (Monogenea, Ancyrocephalidae) on the gills of Pseudocrenilabrus philander (Weber, 1897) (Cichlidae).

Histopathological changes of Cichlidogyrus philander Douëllou, 1993 on the gills of Pseudocrenilabrus philander (Weber, 1897) were studied using light and scanning electron microscopy. Observations revealed that C.philander attaches to its host by alternating the prohaptor (for temporary attachment or feeding) or haptor (using haptoral parts for firm and secured attachment). The sharp terminal ends of the anchors are inserted basally into the gill lamella, between two adjacent secondary gill lamellae and the marginal hooklets assist by superficially penetrating, holding and lifting epithelial tissue in the proximal region of the secondary gill lamella. The attachment of C.philander resulted in compression, rupturing of the interlamellar epithelium, change in the organization of epithelial cells in both primary and secondary gill lamella, displacement of the extracellular cartilaginous matrix, occasional rupturing of blood vessels and erythrocytes and some cells becoming ill-defined. At the site of attachment, the host response comprises of hyperplasia, increase in the number of mucous cells and infiltration with neutrophils. It was concluded that the effect of C.philander is mild in natural conditions.

Histopathological Effect of Pesticide Cypermethrin Toxicity on Liver and Gill of Freshwater Fish, Oreochromis Mossambicus (Tilapia)

Pollution is now a day has become a threat to living beings. Pollutants in the form of pesticide inhabit a variety of environments which affect the normal vital activities of organisms living. They reach the aquatic environment as a washout from agriculture fields as well as from industrial areas. Pesticide contamination in water may accumulate in the bodies of animals and affect the vital organs which alter the usual activities. Cypermethrin is a synthetic pyrethrum insecticide used in agriculture to control pest in crops such as lettuce and cotton and household pest such as cockroach. To understand the toxic effect of pesticides, it creates a need for histopathological observation of tissues. Present work was carried to evaluate the toxic effect of cypermethrin (25% EC) in liver and gills of tilapia (O.mossambicus). The fish experimented to different sublethal concentration of 1/10th,1/20th and 1/30th level of LC50 (4.5 mg/l) value of cypermethrin for 30 days. Gill exhibited epithelial cell damage, Fusion , Length reduction , Curling and Repturing of secondary gill lamellae, primary gill lamellae Enlargement, Necrosis, Cytoplasmic vacuolization, Damaged red blood corpuscle, Excessive secretion of mucus, whereas liver showed increased vacuolization, Necrosis, Hyperplasia, disintegration of hepatocytes and necrotic nuclei. Aim of the present study is to identify the effect of cypermethrin on organs tissues ( liver, kidney) of freshwater fish, Oreochromis mossambicus.
 Keywords: Cypermethrin, Oreochromis mossambicus, Gill, Liver

EFFECT OF AZARDIRACHTA INDICA LEAF EXTRACT ON GILL OF FRESHWATER FISH, LABEO ROHITA

An investigation on the toxicity of biopesticidal plant Azardiracta indica aqueous leaf extracts to Labeo rohita. The LC50 value of Azardiracta indica aqueous leaf extracts was 1.1ml/lit respectively. The sub lethal concentration for Azardiracta indica was 0.11ml/lit and 0.33 ml/lit respectively. The fishes were exposed to the sub lethal concentration for a period of 15 days. At the end of 15th day the fishes were dissected and the gill were removed from exposed and control group fishes. The tissues were processed and sectioned at 4µm and then were stained with Haematoxylin- Eosin. The observation of the slides was done under light microscope at 40x magnification and photographed. The exposed group showed histopathological changes in the tissues, such as: shrunken and narrow secondary gill lamellae, mild to moderate infiltration of inflammatory cells in the primary and secondary gill lamellae. This result indicated that the aqueous extract of Azardiracta indica has considerable impact on the respiratory organ of fresh water fish, Labeo rohita.
 Key words: Labeo rohita, Azardiracta indica, secondary lamellae

Toxicity of zinc oxide nanoparticles (ZnO-NPs) in tilapia (Oreochromis mossambicus): tissue accumulation, oxidative stress, histopathology and genotoxicity

Zinc oxide nanoparticles (ZnO-NPs) are being widely used in numerous industrial and commercial applications. This study was designed to investigate the possible mechanisms of bioaccumulation, oxidative stress, histopathological alterations and genotoxicity induced by ZnO-NPs to tilapia (Oreochromis mossambicus). The study showed maximum Zn accumulation of 3.0643 mg/kg (p < 0.05) in liver at highest concentration of 1.5 mg/L in T3. ZnO-NPs induced oxidative stress as indicated by the significantly increased LPO level in gills as compared to liver (p < 0.05). The increased lipid peroxidase (LPO) and superoxide dismutase (SOD) levels were observed in gills than liver. Similar results were observed for catalase (CAT) and glutathione (GSH) in gills. In case of histological alterations, gill oedema and hyperplasia, fusion of gill lamellae and thickening of primary and secondary gill lamellae were observed. In liver, necrosis and apoptosis with condensed nuclear bodies and pyknotic nuclei were observed. The genotoxic potential was investigated by evaluating DNA strands break using alkaline comet assay, and significant DNA damage was observed in the erythrocytes when exposed for ZnO-NPs. The % tail DNA was increased with the increasing concentration of ZnO-NPs, and similar pattern was shown in olive tail movement. Overall, we conclude that the ZnO-NPs have the potential to accumulate in the soft tissues, causing respiratory distress such as oxidative stress, induction of antioxidant defence mechanism by raising glutathione (GSH), organ pathology and genotoxicity. These results suggest the potential ecotoxicological effects of nanoparticles in understanding their uptake and effects on aquatic biota.

Evaluating toxicity of copper(II) oxide nanoparticles (CuO-NPs) through waterborne exposure to tilapia (Oreochromis mossambicus) by tissue accumulation, oxidative stress, histopathology, and genotoxicity.

Metal oxide nanoparticles are widely used in industries, and peak level can be confirmed in their surroundings. In the present study, the sub-lethal effects of CuO-NPs from low to high concentration as 0.5 to 1.5mg/L were observed in tilapia (Oreochromis mossambicus). Accumulation of copper from CuO-NPs was increased with the increase in doses, and maximum accumulation was found in the gill than liver and muscles. The increased lipid peroxidation level was observed in the gill as compared to liver, and the similar results were obtained in catalase and glutathione while superoxide dismutase level was higher in the liver than gills. In histological alterations, gill edema, curved tips, fusion of gill lamellae, and thickening of primary and secondary gill lamellae were observed. Necrosis and apoptosis with condensed nuclear bodies and pyknotic nuclei were observed in the liver at the highest dose concentration. In a genotoxic study, the highest value of % tail DNA and olive tail movement was observed with increasing concentrations. Copper oxide nanoparticles has greater potential to accumulate in the soft tissues, which may cause respiratory distress such as oxidative stress, induction of antioxidant defense by raising glutathione, organ pathology, and genotoxicity.

Histopathological alterations and condition factor deterioration accompanied by isopod infestation in Tilapia zilli, Mugil capito and Solea aegyptiaca from Lake Qaroun

This study was carried out to identify isopod species implicated in the outbreak that had affected commercially important fishes of Lake Qaroun. The study also aims to determine its deleterious effects on infested fish and its possible role in the severe drop in lake fisheries production. Renocila thresherorum (Crustacea: Isopoda: Cymothoidae) was the only isopod species isolated from the fishes in the lake. The overall prevalence was 38% as 37.14, 25.7 and 53.3% of the examined Tilapia zilli (Gervais, 1848), Mugil capito (Cuvier, 1829) and Solea aegyptiaca (Chabanaud, 1927), respectively, they were found to be infested; while the recorded intensity was 1.23 for T. zilli and 1 for both M. capito and S. aegyptiaca. The main clinical sign noticed was a unilateral or bilateral bulged operculum, with the presence of a large sized isopod female which reached up to 23 mm in length in gill chamber, pale atrophied and eroded gill filament. The condition factor of infested fish significantly decreased in comparison with that of non-infested fish. Various degrees of degenerative pathological lesions including destruction, detachment, hyperplasia and fusion of the primary and secondary gill lamellae were observed in infested fish gills. The current research proved the deleterious effect of R. thresherorum on Lake Qaroun fishes based on clinical finding, condition factor calculation and histopathological examination.

ECOTOXICOLOGY OF GREEN SYNTHESIZED SILVER NANOPARTICLES ON FRESH WATER FISH MYSTUS GULIO

Objective: Nanotechnology an advanced tool to synthesis atomic level particles. Increased application of silver nanoparticles results in the bioaccumulation of these particles in the environment. The biological effect of the green synthesized silver nanoparticles on the fresh water cat fish ws studied in the present study.Methods: Asystasia gangetica leaf extract was used to synthesize silver nanoparticles, the particles were characterized by scanning electron microscopy. Fifteen days after the introduction of fishes into the medium containing AgNPs, the fishes were sacrificed and the tissues were processed for biochemical and histological studies. Na+-K+-ATPase was estimated using LeBel method. Estimation of carbohydrate was done by the Phenol-sulphuric acid method. Total protein was estimated using Lowry’s method, Sulpho-Vanilline method was used to estimate the total lipids.Results: The results observed in the present study reveals a marked difference in the level of carbohydrate in the muscle tissue from 48.338±0.320 to 22.747±1.837 µg/100 mg wet tissue followed by gills and liver with 41.21% and 25.48% decrease. Total protein content was decreased from 649.094±1.429 to 491.56±0.925 µg/mg wet tissues. The drastic increase in the total lipids was observed in liver tissue of treated fishes from 0.240±0.004 to 0.408±0.005 mg/gm wet tissue. Na+-K+-ATPase activity of liver tissue increased from 0.153±0.001 to 0.225±0.003 in the liver tissue of treated fishes, followed by muscles and gills with 33.61% and 35% of the increase in the activity. Marked changes in the structure of gills with degenerated primary gill lamellae, necrosis, hyperplasia and fused primary lamellae were evident in experimental group. Necrosis, vacuolization, disintegrated nucleus and blood sinusoids were observed in liver tissues. Disintegration of myofibrils was evident in AgNP treated group of fishes.Conclusion: The plant-mediated synthesized AgNPs shows a potential toxic effect on all the tissues studied; changes were observed in the normal architecture of tissues as well as in the biochemical parameters. To understand the mechanism of toxicity of these particles further studies at the molecular level has to be carried out.

Cytotoxic and genotoxic affects of acid mine drainage on fish Channa punctata (Bloch)

The investigation deals with the effects of Acid Mine Drainage (AMD) of coal mine on fish Channa punctata (Bloch) by examining the incidence of haematological, morphological, histological changes and DNA fragmentation in tissues of C. punctata in laboratory condition. For this study fishes were exposed to 10% of AMD for a period of 30 days. The fusion of the primary and secondary gill lamellae, distortion, loss of alignment, deposition of worn out tissues and mucous on the surface of the lamella in the gills; degeneration of morphological architecture, loss of alignment of tubules, mucous deposition in the kidney; cellular damage, cellular necrosis, extraneous deposition on the surface, pore formation in the liver are some important changes detected by scanning electron microscopy. Fishes of AMD treated group showed gradual significant decrease in TEC, Hb and, increase in TLC and DLC as compared to that of the control. DNA fragmentation observed in kidney of fishes from treated group indicates an intricate pollutant present in the AMD. The high incidence of morphological and histological alterations, haematological changes along with DNA breakage in C. punctata is an evidence of the cytotoxic and genotoxic potential of AMD of coal mines.

Myxobolus lepomis n. sp. (Cnidaria: Myxobolidae), a gill myxozoan infecting Lepomis marginatus Holbrook and Lepomis miniatus Jordan (Perciformes: Centrarchidae), in the Big Thicket National Preserve, Texas, USA.

A parasitological survey of freshwater fishes in the Big Thicket National Preserve in southeast Texas revealed myxozoan infections in two species of sunfish, Lepomis marginatus Holbrook and Lepomis miniatus Jordan (Perciformes: Centrarchidae). Pseudocysts were elongate-oval, 988 × 485 µm (ex L. marginatus) and 800 × 606 µm (ex L. miniatus) and demonstrated a predilection to the edge of the primary gill lamellae. Myxospores consistent with the genus Myxobolus were oblong, 16.8-21.3 (19.0 ± 0.9) µm long, 7.0-8.8 (7.9 ± 0.5) µm wide and 5.3-6.1 (5.8 ± 0.3) µm thick (ex L. marginatus) and 17.2-20.3 (18.8 ± 0.7) µm long, 7.5-9.9 (8.7 ± 0.6) µm wide, and 6.8-7.2 (7.0 ± 0.2) µm thick (ex L. miniatus); with 2 pyriform polar capsules 8.3-9.8 (9.0 ± 0.5) µm long, 2.2-2.7 (2.5 ± 0.2) µm wide (ex L. marginatus) and 9.2-10.5 (10.0 ± 0.4) µm long, 2.2-3.0 (2.8 ± 0.2) µm wide (ex L. miniatus). Statistically, the measurements of spore body width, polar capsule length, and polar capsule width were significantly different between myxospores from L. marginatus and L. miniatus. However, intraspecific genetic variability between isolates at the 18S rRNA gene was negligible, with < 0.8% variability across > 2,000 bp of sequence. The isolates shared no significant sequence similarity with any myxozoan deposited in the GenBank nucleotide database. Phylogenetic analysis inferred from the 18S rRNA gene from both L. marginatus and L. miniatus placed the isolates within a clade of myxozoan parasites of perciform fishes. Based on shared tissue and host family tropism, overlapping morphological characters and high degrees of sequence conservation at the 18S rRNA gene, we propose these isolates as morphologically distinct, genetically conspecific representatives of M. lepomis n. sp. from the gills of L. marginatus and L. miniatus in the Big Thicket National Preserve in Texas, USA.