This study evaluated the total and differential leukocyte counting and the phagocytic activity in... more This study evaluated the total and differential leukocyte counting and the phagocytic activity in Nile tilapia Oreochromis niloticus experimentally injected with Enterococcus sp. in the swim bladder. Fish were distributed in four treatments in triplicates of non-injected fish, fish injected with 1 ml of sterile saline solution 0.65%, and fish injected with 1 9 10 3 and 1 9 10 6 colony-forming units (CFU) of Enterococcus diluted in 1 ml sterile saline. Twenty-four hours after injection, the fish were anesthetized and the blood collected for white blood cell (WBC) counts, differential counting of WBC, and phagocytic activity of blood leukocytes. The increased numbers of WBC and lymphocytes were followed by decreased number of monocyte after infection. The percentages of phagocytic activities in the blood were 55.3 and 55.9%, respectively, in tilapia injected with 1 9 10 3 and 1 9 10 6 CFU/ml.
Zoonotic Fusarium oxysporum infection was identified in captive-reared fingerlings of golden mahs... more Zoonotic Fusarium oxysporum infection was identified in captive-reared fingerlings of golden mahseer, Tor putitora (Hamilton, 1822) from the central Himalayan regions, India. Initially, fingerlings of T. putitora (mean length 10.8 ± 0.002 and weight 18.58 ± 0.054 g) were observed with cottony mass like growth completely covering the dorsal and caudal fins. The infected fingerlings were showing clinical signs such as sluggish, erratic movement, gasping, flared operculum and settling at one corner of the rearing tanks. The microscopic observation of 8-day old culture of cottony mass like growth showed the presence of septate macroconidia, randomly spread microconidia and chlamydospores in short-chain. From sequence analysis of ITS amplified fragment, the isolate was identified as Fusarium oxysporum, TPFCF 214 (MH464266.1) and clustered with F. oxysporum, strain NRRL 43504 (EF453107.1) and F. oxysporum, strain 20736 (JX 270150.1) isolated from the human in phylogenetic tree. An experimental infection of healthy golden mahseer fingerlings with 20 µl of F. oxysporum spore suspension (2.5 × 10 9 spore ml −1) showed the development of lesion 6-dpi at the site of injection. Experimental trial on EPC-2 cell culture recorded detachment in the monolayer, clumping and shrinking of the cell line 6-8 dpi with a spore suspension of F. oxysporum, TPFCF 214 (5.68 × 10 2 cell/ml). From the severity of its infection, there is a chance that F. oxysporum may emerge as pathogenically and pose a significant health risk on captive-reared golden mahseer in other Asian countries and world. As Fusarium solani and F. oxysporum are known to cause invasive fusariosis in human especially in immunocompromised patients, localized infection in immunocompetent individuals as well as osteomyelitis, arthritis, otitis, sinusitis and brain abscess, the global fish farmers, handlers and aquaculturist need to be aware of possible health hazards caused by Fusarium spp. and should adopt proper fish health management and animal husbandry practice to control the infection of Fusarium in culture environment.
Microcystins (MCYST) are the freshwater cyanobacterial toxins, known to induce hepatocellular car... more Microcystins (MCYST) are the freshwater cyanobacterial toxins, known to induce hepatocellular carcinoma, necrosis, intrahepatic bleeding, as well as human and livestock mortality. Within hepatocytes, MCYST selectively bind to protein phosphatases 1 and 2A, resulting in severe liver damage. The toxicology of MCYST in mice and rats has been well studied, but little is known regarding genotoxicity in aquatic animals. In this study, the zebrafish, Danio rerio was exposed to crude extract of Microcystis aeruginosa bloom. Liver and heart were examined for MCYST-induced toxicity. Light microscopy at 36 h revealed severe, widespread apoptotic necrosis of the majority of hepatocytes, and cytoskeletal deformation in myocardiocytes. Hepatocytes were dissociated with cell shrinkage and margination of nuclear chromatin. Laddering of genomic DNA from the liver and heart of the exposed fish in an increment of 180–200 bp was consistent with apoptosis. Fluorimetric analysis of DNA unwinding was carried out to determine the DNA strand breakage. After 36 h exposure, the % double-stranded DNA was significantly reduced in hepatocytes and myocardiocytes. In conclusion, the results obtained in this study indicate that, the extract of M. aeruginosa bloom is genotoxic to fish. The DNA damage observed in this study may be attributed to the activation of DNA endonucleases. This model of DNA damage may contribute for identifying novel molecular mechanisms of interest for therapeutic application.
This study evaluated the total and differential leukocyte counting and the phagocytic activity in... more This study evaluated the total and differential leukocyte counting and the phagocytic activity in Nile tilapia Oreochromis niloticus experimentally injected with Enterococcus sp. in the swim bladder. Fish were distributed in four treatments in triplicates of non-injected fish, fish injected with 1 ml of sterile saline solution 0.65%, and fish injected with 1 9 10 3 and 1 9 10 6 colony-forming units (CFU) of Enterococcus diluted in 1 ml sterile saline. Twenty-four hours after injection, the fish were anesthetized and the blood collected for white blood cell (WBC) counts, differential counting of WBC, and phagocytic activity of blood leukocytes. The increased numbers of WBC and lymphocytes were followed by decreased number of monocyte after infection. The percentages of phagocytic activities in the blood were 55.3 and 55.9%, respectively, in tilapia injected with 1 9 10 3 and 1 9 10 6 CFU/ml.
Zoonotic Fusarium oxysporum infection was identified in captive-reared fingerlings of golden mahs... more Zoonotic Fusarium oxysporum infection was identified in captive-reared fingerlings of golden mahseer, Tor putitora (Hamilton, 1822) from the central Himalayan regions, India. Initially, fingerlings of T. putitora (mean length 10.8 ± 0.002 and weight 18.58 ± 0.054 g) were observed with cottony mass like growth completely covering the dorsal and caudal fins. The infected fingerlings were showing clinical signs such as sluggish, erratic movement, gasping, flared operculum and settling at one corner of the rearing tanks. The microscopic observation of 8-day old culture of cottony mass like growth showed the presence of septate macroconidia, randomly spread microconidia and chlamydospores in short-chain. From sequence analysis of ITS amplified fragment, the isolate was identified as Fusarium oxysporum, TPFCF 214 (MH464266.1) and clustered with F. oxysporum, strain NRRL 43504 (EF453107.1) and F. oxysporum, strain 20736 (JX 270150.1) isolated from the human in phylogenetic tree. An experimental infection of healthy golden mahseer fingerlings with 20 µl of F. oxysporum spore suspension (2.5 × 10 9 spore ml −1) showed the development of lesion 6-dpi at the site of injection. Experimental trial on EPC-2 cell culture recorded detachment in the monolayer, clumping and shrinking of the cell line 6-8 dpi with a spore suspension of F. oxysporum, TPFCF 214 (5.68 × 10 2 cell/ml). From the severity of its infection, there is a chance that F. oxysporum may emerge as pathogenically and pose a significant health risk on captive-reared golden mahseer in other Asian countries and world. As Fusarium solani and F. oxysporum are known to cause invasive fusariosis in human especially in immunocompromised patients, localized infection in immunocompetent individuals as well as osteomyelitis, arthritis, otitis, sinusitis and brain abscess, the global fish farmers, handlers and aquaculturist need to be aware of possible health hazards caused by Fusarium spp. and should adopt proper fish health management and animal husbandry practice to control the infection of Fusarium in culture environment.
Microcystins (MCYST) are the freshwater cyanobacterial toxins, known to induce hepatocellular car... more Microcystins (MCYST) are the freshwater cyanobacterial toxins, known to induce hepatocellular carcinoma, necrosis, intrahepatic bleeding, as well as human and livestock mortality. Within hepatocytes, MCYST selectively bind to protein phosphatases 1 and 2A, resulting in severe liver damage. The toxicology of MCYST in mice and rats has been well studied, but little is known regarding genotoxicity in aquatic animals. In this study, the zebrafish, Danio rerio was exposed to crude extract of Microcystis aeruginosa bloom. Liver and heart were examined for MCYST-induced toxicity. Light microscopy at 36 h revealed severe, widespread apoptotic necrosis of the majority of hepatocytes, and cytoskeletal deformation in myocardiocytes. Hepatocytes were dissociated with cell shrinkage and margination of nuclear chromatin. Laddering of genomic DNA from the liver and heart of the exposed fish in an increment of 180–200 bp was consistent with apoptosis. Fluorimetric analysis of DNA unwinding was carried out to determine the DNA strand breakage. After 36 h exposure, the % double-stranded DNA was significantly reduced in hepatocytes and myocardiocytes. In conclusion, the results obtained in this study indicate that, the extract of M. aeruginosa bloom is genotoxic to fish. The DNA damage observed in this study may be attributed to the activation of DNA endonucleases. This model of DNA damage may contribute for identifying novel molecular mechanisms of interest for therapeutic application.
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