Effect of exposure to sublethal concentrations of sodium cyanide on the carbohydrate metabolism of the Indian Major Carp Labeo rohita (Hamilton, 1822)

Experiments were designed to study in-vivo effects of sodium cyanide on biochemical endpoints in the freshwater fish Labeo rohita. Fish were exposed to two sublethal concentrations (0.106 and 0.064mg/L) for a period of 15 days. Levels of glycogen, pyruvate, lactate and the enzymatic activities of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (G6PDH), phosphorylase, alkaline phosphatase (ALP), acid phosphatase (AcP) were assessed in different tissues (liver, muscle and gills). Result indicated a steady decrease in glycogen, pyruvate, SDH, ALP and AcP activity with a concomitant increase in the lactate, phosphorylase, LDH and G6PD activity in all selected tissues. The alterations in all the above biochemical parameters were significantly (p<0.05) time and dose dependent. In all the above parameters, liver pointing out the intensity of cyanide intoxication compare to muscle and gills. Study revealed change in the metabolic energy by means of altered metabolic profile of the fish. Further, these observations indicated that even sublethal concentrations of sodium cyanide might not be fully devoid of deleterious influence on metabolism in L. rohita.

Responsiveness of the interrenal tissue of Jundia (Rhamdia quelen) to an in vivo ACTH test following acute exposure to sublethal concentrations of agrichemicals

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Surface morphology of Diplodon expansus (Kuster, 1856; Mollusca, Bivalvia, Hyriidae) gill filaments after exposure to environmentally relevant concentrations of atrazine herbicide

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sublethal effects of suspended sediments on estuarine fish /

The objective of this study was to determine the effects, if any, of sublethal concentrations of suspended materials on the fish in estuarine systems. Experimental sediment suspensions reproduced the concentrations frequently found during flooding and at dredging sites and dredged-material disposal sites. The suspensions were of natural sediment, obtained from the Patuxent River estuary, Maryland, or commercially available Fuller's earth. Fish were collected in the Patuxent River estuary and transported to the laboratory. The selected fish species inhabited ecologically different sections of the estuary; therefore, the overall reactions of each species were unique. Seven species of estuarine fish were exposed to Fuller's earth and natural sediment suspensions for timed periods and hematological changes were noted. The effects of various concentrations of Fuller's earth suspensions on white perch gill tissue were determined. Oxygen consumption rates of striped bass, white perch, and toadfish were measured in filtered Patuxent River water and compared to consumption rates in filtered river water suspensions of Fuller's earth or Patuxent River sediment. Fish showed signs of stress in response to suspended sediments in most of the experiments. Results indicate that sublethal concentrations of suspended solids can affect estuarine fish.

Characterisation of an antiviral pediocin-like bacteriocin produced by Enterococcus faecium

The bacteriocin-producing strain Enterococcus faecium ST5Ha was isolated from smoked salmon and identified by biomolecular techniques. Ent. faecium ST5Ha produces a pediocin-like bacteriocin with activity against several lactic acid bacteria, Listeria spp. and some other human and food pathogens, and remarkably against HSV-1 virus. Bacteriocin ST5Ha was produced at high levels in MRS broth at 30 degrees C and 37 degrees C, reaching a maximum production of 1.0 x 10(9) AU/ml, checked against Listeria ivanovii ATCC19119 as target strain and surrogate of pathogenic strain Listeria monocytogenes. The molecular weight of bacteriocin ST5Ha was estimated to be 4.5 kDa according to tricine-SDS-PAGE data. Ent. faecium ST5Ha harbors a 1.044 kb chromosomal DNA fragment fitting in size to that of pediocin PA-1/AcH. In addition, the sequencing of bacteriocin ST5Ha gene indicated 99% of DNA homology to pediocin PA-1/AcH. The combined application of low levels (below MIC) of ciprofloxacin and bacteriocin ST5Ha resulted in a synergetic effect in the inhibition of target strain L ivanovii ATCC19119. Bacteriocin ST5Ha displayed antiviral activity against HSV-1, an important human pathogen, with a selectivity index of 173. To the best of our knowledge, this is the first report on Ent. faecium as a potential producer of pediocin-like bacteriocin with antiviral activity. (C) 2010 Elsevier Ltd. All rights reserved.

Effect of bioactive compounds extracted from euphorbious plants on hematological and biochemical parameters of Channa punctatus

Channa punctatus was exposed to four different concentrations of Rutin, Taraxerol and Apigenin. Changes in some hematological parameters of Channa punctatus were assessed to determine the influence of these compounds on test fish. Fish were exposed to sublethal concentrations (80% of LC50 of 24h) of these compounds for one week. Control fish were also administered for one week. Thereafter, blood samples were obtained from the control and experimental fish. Blood was assayed for selected hematological parameters (hematocrit, hemoglobin, red blood cell count, white blood cell count total plasma protein and plasma glucose concentration). The derived hematological indices of mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) were calculated. Sublethal concentrations of these compounds caused a dose dependent decrease in hemoglobin values coupled with a decrease in hematocrit values and red blood cell counts are an obvious indication of anemia. The total white blood cell counts and the differential white blood cell counts were decreased except for the lymphocytes, where there was a slight increase. Plasma protein and glucose were also lower in exposed fish when compared with control. The hematological indices MCH, MCHC, MCV were also lowered. The result from this study reveals high mortality rate and deleterious consequences on the health of fish subjected to acute exposure of Rutin, Taraxerol and Apigenin and therefore, should not be used directly in aquaculture without having the proper knowledge.

Toxicological effects of a pharmaceutical, simvastatin, in Gammarus locusta: histopathological evaluation

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente

Bioactivity of plant extracts on the larval and pupal stages of Aedes aegypti (Diptera, Culicidea)

Introduction Aedes aegypti is responsible for the transmission of the dengue and yellow fever viruses. This study evaluated the effects of extracts from Cnidosculos phyllacanthus, Ricinus communis, and Coutarea hexandra on the developmental periods of A.aegypti larvae and pupae. Crude extracts of C. phyllacanthus and C. hexandra and oil from R. communis and C. phyllacanthus were used. Methods Bioassays of the larvicidal and pupicidal effects of these products at different concentrations and times of exposure were evaluated. The lethal and sublethal effects were determined using different concentrations in larvicidal tests. Mortality data were evaluated by Probit analysis to determine the LC50 and LC90 values. Results The vegetable oils from C. phyllacanthus and R. communis demonstrated greater efficiency for larval control with an LC50=0.28µl/mL and an LC90=1.48µl/mL and LC50=0.029µl/mL and a LC90=0.26µl/mL, respectively. In pupal tests toxic effects for all insects were verified after exposure to the products at significant LC50 and LC90 values for 24 and 48h. The effects of sublethal concentrations of C. phyllacanthus (oil) were more effective on the insects. Conclusions The vegetables oils from C. phyllacanthus and R. communis demonstrated greater potential from the control of different developmental periods in the life cycle of this insect.

Pyrethroid toxicity in silver catfish, Rhamdia quelen

This study aimed to determine both the lethal and sublethal concentrations of Cypermethrin in young Silver Catfish (Brazilian "Jundiá", Rhamdia quelen) on aquatic environment during 96 hours, as well as to determine the Cypermethrin and Deltamethrin sublethal concentrations during the initial embryonic development period of Rhamdia quelen, and to verify their respective rates of fertilization, hatching and survival. Pyrethroid nowadays is a widely used insecticide, which presents a high toxicity to fish. In order to determine lethal and sublethal concentrations, 120 silver catfish were used; each one had an average weight of 59.58±4.50g and an average size of 20.33±2.34cm. Concentrations used were 0, 1.0, 1.5, 2.0, 2.5, 3.0, 5.0, 10.0, 15.0 and 20.0mg of Cypermethrin per liter of water (mg/L). Fish were exposed to the product in 30-liter fish tanks. In each fish tank there were four fishes and the product was applied three times, i.e., a total of twelve fish were exposed to the product at each application, and a total of 120 fish during the entire experiment (n=120). In order to determine the Cypermethrin and Deltamethrin sublethal concentrations during the initial embryonic development, ovulation induction was performed on female fishes using hormones, and then and egg collection was performed. The eggs were then hydrated and fertilized in Cypermethrin and Deltamethrin in different concentrations: 0.001, 0.01, 0.1, 1.0 and 10.0mg/L of Cypermethrin and 0.001, 0.01, 0.1, 0.5 and 1.0mg/L of Deltamethrin, in addition to the control group (0mg/L). After fertilization, the eggs were kept in containers with the respective pesticides of Cypermethrin and Deltamethrin until hatching, when hatching rate was verified. Then the alevins, from the hatching, were kept on their respective concentrations of Cypermethrin and Deltamethrin so that the survival rate could be analyzed regarding the tested insecticides, during both 12-hour and 24-hour periods. Concerning the sublethal and lethal concentrations, Silver Catfish was sensitive to the tested concentrations of Cypermethrin, showing symptoms of poisoning, such as loss of balance, swimming alteration, dyspnea (they kept their mouths and opercula open), upright swimming and sudden spiral swimming movements. The intensity of such symptoms varied in proportion to the concentration used. The concentrations above 3.0mg/L were considered lethal to the species, since every animal exposed to concentrations between 3.0 and 20.0mg/L had died, while concentrations between 1.0 and 2.5mg/L were considered sublethal. Lethal concentration of Cypermethrin to Silver catfish, in 96 hours, was 1.71 milligram per liter of water. Concerning the sublethal concentration of Cypermethrin and Deltamethrin during the initial embryonic development, the results show that both pyrethroids had significantly decreased the analyzed parameters when comparing them with the control group. It was concluded that, even with the fish being more resistant to pyrethroids in comparison with other species, both the young animals and the ones in stage of embryonic development were susceptible to the effects of these pesticides.

Increased immunoglobulin production in silver catfish (Rhamdia quelen) exposed to agrichemicals

Fish vaccination has been increasingly exploited as a tool to control pathogen infection. The production of immunoglobulin following vaccination might be affected by several factors such as management procedures, water temperature, and the presence of xenobiotics. In the present study, we aimed to investigate the kinetics of immunoglobulin production in silver catfish (Rhamdia quelen) inoculated with inactivated Aeromonas hydrophila and kept at two different water temperatures (17.4±0.4° or 21.3±0.3°C). The effect of a second antigen inoculation and exposure of fish to sublethal concentrations of the herbicides atrazine and glyphosate at 10% of the lethal concentration (LC50-96h) on specific serum antibodies were also investigated. Antibodies to A. hydrophila were detected as early as 7 days post-inoculation and increased steadily up to 35 days. The kinetics of antibody production were similar in fish kept at 17.4±0.4° and 21.3±0.3°C, and reinoculation of antigen at 21 days after priming failed to increase specific antibody levels. Intriguingly, we found that, in fish exposed to atrazine and glyphosate, the secretion of specific antibodies was higher than in non-exposed inoculated fish. These findings are important for the design of vaccines and vaccination strategies in Neotropical fish species. However, because atrazine and glyphosate are widespread contaminants of soil and water, their immune-stimulating effect could be harmful, in that fish living in herbicide-contaminated water might have increased concentrations of nonspecific antibodies that could mediate tissue injury.

Biochemical effects of the pesticide Chlorpyrifos on the fish Oreochromis mossambicus (Peters)

Man uses a variety of synthetic material for his comfortable materialistic life. Thus human interactions may become harmful for various terrestrial and aquatic lives. This is by contaminating their habitat and by becoming a threat to organisms itself. Thus the application and dispersal of several organic pollutants can lead to the development of several mutated forms of the species when exposed to sublethal concentrations of the pollutants. Otherwise, a decrease in number or extinction of these exposed species from earth's face may happen. Pesticides, we use for the benefit of crop yield, but its persistence may become havoc to non-target organism. Pesticides reaching a reservoir can subsequently enter the higher trophic levels. Organophosphorus compounds have replaced all other pesticides, due to its acute toxicity and non-persistent nature.Hence the present study has concentrated on the toxicity of the largest market-selling and multipurpose pesticide, chlorpyrifos on the commonly edible aquatic organism, fish. The euryhaline cichlid Oreochromis mossambicus was selected as animal model. The study has concentrated on investigating biochemical parameters like tissue-specific enzymes, antioxidant and lipid-peroxidation parameters, haematological and histological observations and pesticide residue analysis.Major findings of this work have indicated the possibility of aquatic toxicity to the fish on exposure to the insecticide chlorpyrifos. The insecticide was found as effective to induce structural alteration, depletion in protein content, decrease in different metabolic enzyme levels and to progress lipid peroxidation on a prolonged exposure of 21 days. The ion-transport mechanism was found to be adversely affected. Electrophoretic analysis revealed the disappearance of several protein bands after 21days of exposure to chlorpyrifos. Residue, analysis by gas chromatography explored the levels of chlorpyrifos retaining on the edible tissue portions during exposure period of 21days and also on a recovery period of 10 days.

Physiological effects of copper (II) on sunetta scripta L.

In India industrial pollution has become a subject of increasing concern.Incidents of industrial pollution have been reported from many parts of the country. Cochin, the collection site of the present study, being the industrial capital of Kerela is also a harbour, is vulnerable to pollution by trace metal contaminants. In the recent times, pollutants of greatest concern in the aquatic environment are those which are persistent such as toxic heavy metals and the chlorinated hydrocarbons which include insecticides and pesticides.The animals collected from the clam bed situated on the northern side af Cochin bermouth are subject to wide fluctuations in salinity both seasonal and tidal. also; salinity is considered as an important parameter influencing the.-physiological functioning of an organism. Hence, the salinity tolerance of the animal is worked out. Considering the potential vulnerability of Cochin backwaters to heavy metal pollution, the impact of heavy metal copper (II) on the bivalve Sunetta sripta was conceived. Static bioassays were conducted for the determination of the sublethal concentrations of the metal as a preliminary step towards the toxicity studies. Oxygen consumption and filtration rate which are considered as reliable sublethal toxicity indices were employed for investigating the toxic effects of the metal. Bioaccumulation, a physiological phenomenon which can be of importance from the public health point of view, and also in the assessment of environmental quality is also dealt with.

Toxicity, accumulation and depuration of heavy metalsin the brown mussel perna indica

In this thesis certain important aspects of heavy metal toxicity have been worked out. Recent studies have clearly shown that when experimental media contained more than one heavy metals, such metals could conspicuously influence the toxic reaction of the animals both in terms of quantity and nature. The experimental results available on individual metal toxicity show that, in majority of such results, unrealistically high concentrations of dissolved metals are involved. A remarkable number of factors have been shown to influence metal toxicity such as various environmental factors particularly temperature and salinity, the condition of the organism and the ability of some of the marine organisms to adapt to metallic contamination. Further, some of the more sensitive functions like embryonic and larval development, growth and fecundity, oxygen utilization and the function of various enzymes are found to be demonstrably sensitive in the presence of heavy metals. However, some of the above functions could be compensated for by adaptive process. If it is assumed that the presence of a single metal in higher concentrations could affect the life function of marine animals, more than one metal in the experimental media should manifest such effects in a greater scale. Commonly known as synergism or more than additivity, majority of heavy metals bring about synergistic reaction .The work presented in this thesis comprises lethal and sublethal toxicities of different salt forms of copper and silver on the brown mussel Perna indica. during the present investigation sublethal concentrations of copper and silver in their dent effects on survival, oxygen consumption, filtration, accumulation and depuration on Perna indica. The results are presented under different sections to make the presentation meaningful .

Phenotypic and proteomic characterization of multiply antibiotic-resistant variants of Salmonella entetica serovar typhimurium selected following exposure to disinfectants

In previous work, Salmonella enterica serovar Typhimurium strain SL1344 was exposed to sublethal concentrations of three widely used farm disinfectants in daily serial passages for 7 days in an attempt to investigate possible links between the use of disinfectants and antimicrobial resistance. Stable variants OXCR1, QACFGR2, and TOPR2 were obtained following treatment with an oxidizing compound blend, a quaternary ammonium disinfectant containing formaldehyde and glutaraldehyde, and a tar acid-based disinfectant, respectively. All variants exhibited ca. fourfold-reduced susceptibility to ciprofloxacin, chloramphenicol, tetracycline, and ampicillin. This coincided with reduced levels of outer membrane proteins for all strains and high levels of AcrAB-To1C for OXCR1 and QACFGR2, as demonstrated by two-dimensional high-performance liquid chromatography-mass spectrometry. The protein profiles of OXCR1 and QACFGR2 were similar, but they were different from that of TOPR2. An array of different proteins protecting against oxidants, nitroaromatics, disulfides, and peroxides were overexpressed in all strains. The growth and motility of variants were reduced compared to the growth and motility of the parent strain, the expression of several virulence proteins was altered, and the invasiveness in an enteric epithelial cell line was reduced. The colony morphology of OXCR1 and QACFGR2 was smooth, and both variants exhibited a loss of modal distribution of the lipopolysaccharide O-antigen chain length, favoring the production of short O-antigen chain molecules. Metabolic changes were also detected, suggesting that there was increased protein synthesis and a shift from oxidative phosphorylation to substrate level phosphorylation. In this study, we obtained evidence that farm disinfectants can select for strains with reduced susceptibility to antibiotics, and here we describe changes in protein expression in such strains.

Farm disinfectants select for cyclohexane resistance, a marker of multiple antibiotic resistance, in Escherichia coli

Aims: The aim of this study was to determine if three classes of farm disinfectants were able to select for ciprofloxacin or cyclohexane tolerant [ indicative of a multiple antibiotic resistance ( MAR) phenotype] Escherichia coli and if cyclohexane-tolerant E. coli could be isolated from farms. Methods and Results: Chicken slurry containing ca 1 : 99 ratio ciprofloxacin resistant : susceptible E. coli ( 10 different resistant strains examined) was treated for 24 h with each of the disinfectants and examined for survival of resistant : susceptible strains. Ciprofloxacin-sensitive ( n = 5) and - resistant ( n = 5) E. coli were grown with sublethal concentrations of the disinfectants and then plated to agar containing ciprofloxacin or overlaid with cyclohexane. Escherichia coli ( n = 389) isolated from farms were tested for cyclohexane tolerance. Minimum inhibitory concentrations ( MIC) were determined against representative isolates and mutants. The disinfectants did not select for the ciprofloxacin-resistant E. coli in poultry slurry but following growth with each of the three disinfectants, higher numbers ( Pless than or equal to 0(.)023) of cyclohexane-tolerant E. coli were isolated and these had a MAR phenotype. Of the 389 farm E. coli tested, only one was cyclohexane tolerant. Conclusions: It is possible that in a farm environment, E. coli could be exposed to similar concentrations of the disinfectants that are selected for MAR type organisms under these laboratory conditions. Significance and Impact of the Study: Data from this study suggest that cyclohexane-resistant E. coli are not common on farms, but in view of the ease of isolating them in the laboratory with farm disinfectants, further investigations on farms are warranted.