Response of mucous-secreting cells of the gills and intestine to stress during induced spawning of gray mullet, Mugil cephalus

Introduction: An excess of mucus has been observed in the water during induction of mullet spawning. Few data are available on the physiology of mullets during the induced spawning, especially data on the response of mucous-secreting cells in the gills and intestine

Aim of the work: The aims of the present studies were to evaluate the effects of stress on the mucous-secreting cells in the gills and intestine during induced spawning of Mugil cephalus [Teleostei]

Materials and methods: Quantification of possible cell hyperplasia [or depletion] and the chemical composition of the mucous cells during induction of M. cephalus spawning was carried out using histochemical techniques

Results: The majority of mucous cells were concentrated at the edge of the gill filaments. The mucous cell density in the gills was significantly increased during spawning, but it was significantly decreased during preoviposition mortality. However, the mucous cell density in the mucosal layer of the intestine was significantly decreased during spawning and at preoviposition mortality. The size of mucous cells in both the gills and the intestine was significantly decreased during spawning and at preoviposition mortality, whereas its size was significantly increased in the gills after spawning. Two types of glycoproteins [GPs] [acid and neutral] were identified in the mucous cells of the gill and intestine epithelium of M. cephalus. During induction of spawning, the amount of GPs in the mucous cells altered. The amount of each variety of the carbohydrate [intensity of reaction] differed at the different stages during spawning. In general, the secretion of acidic mucous was increased during spawning

Conclusion: The decrease in the GP contents in mucous cells of M. cephalus, as a result of their hypersecretion in response to stress early during handling and acclimation, decreased the production of mucus and reduced its protective role against desiccation of gill and intestine tissue when the ion concentration changed in water during acclimation and induced spawning. This may be considered one of the possible reasons for mortality. Therefore, caution must be exercised not only in acclimation of fish but also in minimization of exposure of fish to stress during induction of spawning

Heavy metal accumulation in certain marine animals along the East Coast of Chennai, Tamil Nadu, India.

Heavy metals disposed through anthropogenic activities find their way into the oceans and seas through the rivers or through direct fall out from factory effluents. These heavy metals resuspend back into the water column along with the sediments and are known to affect the marine animals. Marine animals like fish, prawn, crab and mussel were collected along the East Coast (off Pulicat lake to Chennai Harbour) to evaluate trace metal concentrations in various tissues. The above specimens accumulated heavy metals such as Zn, Pb, Cu, Co, Cr, Ni and Cd. Fish, prawn, crab and mussel revealed higher concentration of heavy metals such as Zn, Pb, Cr Co, Cu and Ni and Cd in low levels. The results revealed that the heavy metal concentrations in the marine animals are below the threshold levels associated with the toxicological effects and the regulatory limits. The bioconcentration factors revealed that the animals have accumulated heavy metals along the food chain rather than from the water column and sediment.

Responses of succinate dehydrogenase and non-specific alkaline phosphatases and mortality of tilapia to ambient pH stress in a sewage-fed aquaculture pond.

The fish, tilapia (Oreochromis mossambicus) of 50-60 g body weight was experimentally exposed to effluent gradients of highly alkaline pH in a sewage-fed aquaculture farm for examining the pH stress-induced responses of mortality and the stress marker enzyme succinate dehydrogenase and the non-specific alkaline phosphatases of fish prior to death at different hours of intoxication. A second trial was performed after two months when water quality changed along the sewage effluent gradient. An in situ experiment was also performed for better understanding of the responses of enzymatic activities attributable to different levels of pH conditions. Time required for 100% mortality of fish tended to increase from 30 min in pH 11.6 to 22 hr in pH 10.2. There was no mortality of fish when water quality improved significantly (with pH ranging between 9.6 to 8.0) after two months. The activities of succinate dehydrogenase and intracellular alkaline phosphatases assayed in gills and liver prior to death of fish tended to reduce with increase in survival hour, following a pattern of decay curve. On the other hand, percent of enzymatic inhibition of the exposed fish over the control increased as the survival hour increased following a pattern of exponential curve. It appears that the highest water pH of 11.6. maximum ratio for ammonium to ammonium hydroxide (1: 21) and reduced level of dissolved oxygen (2.62 mg/l) were perhaps responsible for the 100% mortality of fish within 30 min of their exposure and the enzymatic activities in the gills and liver assayed prior to death of fish tended to reduce as the acclimatization period of fish increased and vice-versa.

Toxicity studies of butachlor to the freshwater fish Channa punctata (Bloch).

The toxicity studies were conducted on the fish Channa punctata (Bloch) by employing static and continuous flow through systems, for the toxicant butachlor (technical grade+) and its commercial formulation+ (machete 50% EC). The LC50 values are 297.89 ppb and 247.46 ppb for 24 hr and 48 hr in static for technical and 636.45 and 546.09 for machete. In continuous flow through the values are 270.05, 233.52 to the technical and 567.85 and 481.49 respectively for machete. The tissues show qualitative accumulation and were quantitatively analysed by gas liquid chromatography (GLC).

Influence of pH and water hardness upon nickel accumulation in edible fish Cirrhinus mrigala.

The freshwater fingerlings of Cirrhinus mrigala were exposed to Nickel in acidic medium pH = 6.0 (5.8-6.2), alkaline medium pH = 9.0 (8.8-9.2) and water hardness (40 mg/l) of CaCO3. The study indicates that nickel accumulation was significantly influenced by pH and hardness of water The concentration was found to be significantly higher at pH = 9.0 than at pH = 6.0. Also the presence of hardness in water results in reduced toxicity of nickel.

Bioaccumulation of Zn, Cu and Cd in Channa punctatus.

Adult Channa punctatus were acutely exposed to LC50 of zinc (18.62 mg/l), cadmium (11.8 mg/l) and copper (0.56 mg/l) separately for 96 hr The concentration of metals was found maximum in liver and minimum in muscles. The degree of accumulation among the five tissues differed and it was in the order: gill>liver>kidney>blood>muscle in case of Zn, gills>kidney>blood> liver>muscle in case of Cd and gills>kidney>blood>liver>muscle in case of Cu exposure.

Trace metal levels in the organs of finfish Oreochromis mossambicus (Peter) and relevant water of Jannapura lake, India.

Trace metal levels in the body organs of finfish, Oreochromis mossambicus (Peter) and relevant water was studied in Jannapura lake, located five kilometers from Bhadravathi town, Karnataka, India, during 2004-05. Lead, Copper and Cadmium accumulation was higher in muscles than in gills while, Zinc, Nickel and Cobalt accumulation was maximum in gills followed by muscles. The metals present in the highest concentration were in the order of Pb > Cu > Zn > Cd > Ni > Co in the water samples. The higher concentration of various metals in water and Pb, Ni in fish muscle and Ni in gill samples was probably due to the addition of untreated sewage, geological weathering and agricultural runoff from the surrounding areas. On the basis of results obtained, it is predicted that if the present situation of water pollution continues in future, survival of fish population and other aquatic animals will be extremely difficult.

Study of carbohydrate metabolism in selected tissues of freshwater mussel, Lamellidens marginalis under copper sulphate toxicity.

Sublethal toxicity of copper sulphate on carbohydrate metabolism was studied in selected tissues of freshwater mussel, Lamellidens marginalis. Levels of glycogen and pyruvic acid decreased while lactic acid showed an increase. Activities of LDH, SDH and MDH decreased while G-6-PDH activity increased. There appears to be a shift in the carbohydrate metabolism from aerobic to anaerobic type due to toxicity of copper.

Karyotype description of Pomacea patula catemacensis (Caenogastropoda, Ampullariidae), with an assessment of the taxonomic status of Pomacea patula

Mitotic chromosomes of the freshwater snail Pomacea patula catemacensis (Baker 1922) were analyzed on gill tissue of specimens from the type locality (Lake Catemaco, Mexico). The diploid number of chromosomes is 2n = 26, including nine metacentric and four submetacentric pairs, therefore, the fundamental number is FN = 52. No sex chromosomes could be identified. The same chromosome number and morphology were already reported for P. flagellata, i.e., the other species of the genus living in Mexico. The basic haploid number for family Ampullariidae was reported to be n = 14 in the literaure; so, its reduction to n = 13 is probably an apomorphy of the Mexican Pomacea snails. Lanistes bolteni, from Egypt, also shows n = 13, but its karyotype is much more asymmetrical, and seems to have evolved independently from P. flagellata and P. patula catemacencis. The nominotypical subspecies, P. patula patula (Reeve 1856), is a poorly known taxon, whose original locality is unknown. A taxonomical account is presented here, and a Mexican origin postulated as the most parsimonious hypothesis.

Expression of heat shock protein 70 in freshwater prawn Macrobrachium malcolmsonii (H. Milne Edwards) following exposure to Hg and Cu.

Juveniles of freshwater prawn M. malcolmsonii were exposed to 1/6th concentration of LC50 of Hg and Cu for 48 hr. Sampling was done at 1 8, 12, 16, 24, 30, 36, 42 and 48 hr of exposure. Gill and hepatopancreas were dissected and subjected to one-dimensional electrophoresis. Western blotting was employed to determine the relative concentration of heat shock protein, hsp 70 (stress-70) in each sample. In the gill tissue of the prawn that had been exposed to Hg (0.024 mgHg 1(-1)), stress-70 was detected from the 1st hr till the 16th hr of exposure. But in the gills of Cu exposed prawn, synthesis of stress-70 appeared from the 1st hr till the 24th hr. Synthesis of hsp70 was not recorded after the 24th hr in the gills of exposed prawns. Synthesis of stress-70 was also found to be tissue-specific for both metals in this prawn. When the antibody probe raised against stress-70 was used, synthesis of stress-70 was not observed in hepatopancreas of prawns exposed to Hg or Cu, during the entire period of exposure of 48 hr. The expression of stress-70 in M. malcolmsonii following exposure to Hg and Cu is apparently only transient, and also a differential expression of stress-70 between gill and hepatopancreas was observed for both the metals.

K+ balance in rainbow trout gill and liver tissue, cell suspensions and cultured cells

Both intact gill and liver tissue from rainbow trout accumulated K+, as determined by 86Rb+ uptake, a process largely inhibited by ouabain, indicating the presence of functional NaKATPase. Cell suspensions, produced by disaggregation of gill or liver tissues, accumulated very little K+ compared to tissues (Less than 10 percent). Disaggregation resulted in depolarisation of cells with loss of intracellular K+ and although NaKATPase, as measured by 86Rb+ uptake rate, remained functional and inhabitable by ouabain, the activity was insufficient to replace the rapid K+ loss. While attached, cultured gill and liver cells showed normal K+/Na+ ratios and NaKATPase activity, but release from the substratum resulted in depolarisation and rapid K+ loss as seen in cell suspensions. These results suggest that care is required in interpreting ionic regulatory and other results from cell suspensions and that further research should be directed towards systems where cells can maintain normal ionic balance.

Sublethal effects of textile dye stuff effluent on selected oxidative enzymes and tissue respiration of Cyprinus carpio (Linn.).

Toxic effects of sublethal concentration of dye stuff effluent on succinic dehydrogenase (SDH) and lactic dehydrogenase (LDH) activities and tissue respiration were studied in C. carpio. While the sublethal exposure significantly reduced SDH activity and tissue respiration, LDH activity increased in gill, brain, liver, muscle and kidney. The maximum inhibition of SDH activity (74%) was recorded in gill and the minimum (38%) in liver. The percentage reduction of oxygen consumption in the tested tissues was in the order of gill greater than brain greater than liver greater than muscle greater than kidney. The muscle showed the highest level (96%) of increase in LDH activity whereas the kidney cells showed the minimum increase. Exposure to sublethal concentration suppressed the aerobic respiration and triggered the anaerobic respiration.

Gill metabolism after chronic subacute zinc treatments

Metabolismo branquial después de tratamientos subagudos crónicos de zinc. Se analizó la concentración de ATP y lactado en el tejido branquial de Scyliorhirus canicula después de tratamientos a corto y largo placo con zinc. Se detectó un incremento de los niveles de lacto y un descenso de ATP a corto plazo, mientras que no se observaron cambios significativos después del tratamiento a largo plazo. Estos resultados sugieren un posible proceso de recuperación o una activación de mecanismos fisiológicos de compensación