Purification, crystallization and preliminary X-ray analysis of haemoglobin I from the armoured catfish Liposarcus anisitsi

Liposarcus anisitsi is an armoured catfish that presents accessorial air oxygenation through a modified stomach, which allows this species to survive in waters with very low oxygen content. Analysis of its haemolysate has shown the presence of four haemoglobins; this work focuses on the main component, haemoglobin I. It has been crystallized in two different forms and X-ray diffraction data have been collected to 2.77 and 2.86 Angstrom resolution using synchrotron radiation. Crystals were determined to belong to the space groups C2 and P2(1) and preliminary structural analysis revealed the presence of one tetramer in the asymmetric unit in both crystal forms. The structure was determined using a standard molecular-replacement technique.

Foam nest production in the armoured catfish

Foam nest production in Hoplosternum littorale is described in detail. This fish produces foam, while swimming belly-up, by pumping water over the gills and using their pelvic fins to mix water and mucus. The bubbles resulting from this process are added to plant debris carried by the male, which possesses a specialized pectoral fin spine to perform such activity. (C) 1997 the Fisheries Society of the British Isles.

Activity of the Ovarian Germinal Epithelium in the Freshwater Catfish, Pimelodus maculatus (Teleostei: Ostariophysi: Siluriformes): Germline Cysts, Follicle Formation and Oocyte Development

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

Life strategies of some long-distance migratory catfish in relation to hydroelectric dams in the Amazon Basin

In this paper, we present evidence that the long-distance migratory catfish Brachyplatystoma filamentosum, B. flavicans, B. vaillantii, Goslinia platynema and Lithodoras dorsalis spawn in the headstreams of the Amazon river and its tributaries and that the estuary of the Amazon is the main nursery ground utilized by their alevins. The impact of hydroelectric dams on their populations are discussed in terms of interruption to fish migration routes up river and to larvae moving down river, provided that the hypothesis above holds. Ways of mitigating the impact are also considered. © 1991.

Effects of stocking density on growth of channel catfish, Ictalurus punctatus, fingerlings in Southern Brazil

Channel catfish, Ictalurus punctatus, fingerlings (mean length: 4.0±0.5 cm) were stocked into sixteen 16-m2 tanks with cement walls and earth bottoms. Four stocking densities were used: 10, 15, 20, and 25 fish/m2. Fish were fed a prepared diet containing 36% protein according to a fish size/water temperature-dependant chart for 120 days. Fish were stocked on January 20, 1992. Average water temperature varied from 19.7°C to 28.5°C. Final mean values of individual fish length and weight were significantly higher (P < 0.05) for the density of 10 fish/m2 and averaged 19.4±2.6 cm and 70.0±16.9 g, respectively. Food conversion ratio was significantly higher (P < 0.05) for fish stocked at rate of 25 fish/m2. Survival rates averaged 91.4%, with no significant differences (P > 0.05) found among treatments. These results demonstrate the viability of channel catfish fingerling growth in southern Brazil.

Crystallization and X-ray diffraction data analysis of oxyhemoglobin-I from the catfish Liposarcus anisitsi (pisces)

Hemoglobin remains, despite the enormous amount of research involving this molecule, as a prototype for allosteric models and new conformations. Functional studies carried out on Hemoglobin-I from the South-American Catfish Liposarcus anisitsi [1] suggest the existence of conformational states beyond those already described for human hemoglobin, which could be confirmed crystallographically. The present work represents the initial steps towards that goal.

Growth of Channel Catfish, Ictalurus punctatus, in Southern Brazil

Despite successful introduction of channel catfish into Brazil in 1980, no studies have been conducted to assess the performance of channel catfish, Ictalurus punctatus, farming in southern Brazil. Fingerlings (27.0 ± 2.2 g) were stocked in sixteen 16-m2 tanks with cement walls and earthen bottoms. Four stocking densities were used: 0.5, 0.75, 1.0, and 1.25 fish/m2. Fish were fed a diet containing 32% protein according to a feeding chart for 257 days (from April to December). Water temperature ranged from 16.4°C to 30°C during the study. Final average weight (727.1 ± 70.6 g) was significantly higher (P < 0.05) for fish raised at 0.5 fish/m2. Food conversion ratio (FCR) was significantly higher (P < 0.05) for fish stocked at 1.25 fish/ m2. Survival averaged 95.4%, and no significant differences (P > 0.05) were found among treatments. There was no significant difference (P > 0.05) in tank production among the densities of 0.75, 1.0, and 1.25 fish/m2, but they were higher (P < 0.05) than the density of 0.5 fish/ m2. These results demonstrate the viability of channel catfish growth in southern Brazil.

Possible effects of sodium chloride treatment on quality of effluents from Alabama channel Catfish ponds

Channel catfish ponds are treated with salt (sodium chloride) to increase chloride concentration and prevent nitrite toxicity in fish. A survey indicated that most farmers try to maintain chloride concentration of 50 to 100 mg/L in ponds by annual salt applications. Averages and standard deviations for selected water quality variables in salt-treated ponds were as follows: chloride, 87.2 ± 37.5 mg/L; total dissolved solids (TDS), 336 ± 96 mg/L; specific conductance, 512 ± 164 μmhos/cm. Maximum values were 189 mg/L for chloride, 481 mg/L for TDS, and 825 μmhos/cm for specific conductance. Good correlations between specific conductance values and both chloride and TDS concentrations suggest that specific conductance can be a rapid method for estimating concentrations of these two variables in surface water. The maximum limit for chloride concentration in Alabama streams allowed by the Alabama Department of Environmental Management is 230 mg/L. The usual recommended upper limit of TDS for protection of aquatic life in freshwater streams is 1,000 mg/L. Based on the observed relationship between TDS concentration and specific conductance in Alabama catfish ponds, 1,000 mg/L TDS corresponds to 1,733 μmhos/cm specific conductance. It is unlikely that effluents from salt-treated catfish ponds would violate the in-stream chloride standard of 230 mg/L or harm aquatic life in streams. Nevertheless, chloride concentrations in ponds should be measured before salt application as a safe guard against excessive salt application and chloride concentrations above the in-stream chloride standard.

Puncture wounds by driftwood catfish during bucket baths: Local habits of riverside people and fish natural history in the Amazon

Objective. - To assess the prevalence of stings by small spiny driftwood catfish (carataí) of the genus Centromochlus (Auchenipteridae) accidentally caught in buckets during bucket bathing by riverside people along the Brazilian Amazon and to determine the probability of catching specimens of these fish during random throws of a bucket into the river. Methods. - We interviewed 27 adult residents living at the confluence of the Negro and Solimões rivers in Brazil regarding whether or not they had ever been stung by driftwood catfish while bucket bathing. To assess the likelihood of catching catfish in bathing buckets, we randomly threw a typical plastic bucket used for bathing in 4 series of 10 throws into the river at dusk or night around a floating house. Results. - Seventeen of the 27 subjects (63%) reported being injured by driftwood catfish during bucket bathing. Three individuals (17.6%) had been injured 2 to 3 times, totaling 23 puncture accidents. All stings occurred at dusk or early night. In the 4 series of 10 bucket throws, we caught 3 driftwood catfish (in 1 series we did not catch any fish). Thus, the chance of catching a driftwood catfish in a single bucket throw at dusk was slightly less than 10%. Conclusions. - The prevalence of stings by driftwood catfish to people bucket bathing in this section of the Brazilian Amazon is high, partly because of the relatively high chances of catching these small catfish during random throws of a bathing bucket into the river.

Bacterial contamination of the catfish (Cathorops agassizii - Valenciennes, 1839 and Genidens genidens - Agassiz, 1829) sting

This work aimed to study the bacterial contamination in stings of the catfish Genidens genidens and Cathorops agassizii found in the São Vicente estuarine system (São Paulo State, Brazil). For bacteriological analyses, we used fish samples distributed into a group of 50 specimens (25 C. agassizii and 25 G. genidens) and a group of 14 specimens (7 C. agassizii and 7 G. genidens). Results showed contamination of 13 different bacterial species of Enterobacteriaceae, being Klebsiella pneumoniae the most frequent bacteria (26.80%) followed by Enterobacter sp and Escherichia coli (16.27%), and Serratia marcescens, Serratia sp. and Proteus mirabilis (1.16%). Gram-positive bacteria as well as fungi were not detected in the samples. According to the Gram-negative species characterized and with regard to the environmental conditions, it can also be considered that accidents with these catfish stings may develop significant acute secondary infections in humans.

Marine catfish sting causing fatal heart perforation in a fisherman

Many marine catfish have serrated bony stings (spines), which are used in defense against predators, on the dorsal and pectoral fins. While catfish-induced injuries are generally characterized by the pain associated with envenomation, the stings in some species are sufficiently long and sharp to cause severe penetrating trauma. Most injuries are to the hands of victims, commonly fishermen. We report the death of a fisherman caused by myocardial perforation from a catfish sting. To our knowledge, this is the first such description in the medical literature.

Time and temperature on the storage of oocytes from jundiá catfish, Rhamdia quelen

The objective of this study was to evaluate the effects of three water and storage temperatures on the oocytes of the jundiá catfish, Rhamdia quelen. A factorial experimental design over time, with treatments completed in triplicate every 48 h, was used (5 × 3 × 3 × 3) to study the exposure of the oocytes to temperatures of 15, 25 and 35. °C and activated with water at 15, 25 and 35. °C each at 0, 45, 90, 135 and 180 minutes post-collection. Linear regression analysis for the response surface model indicated an interaction (p<0.05) between time and temperature of exposure with greater values for fertilization, hatching and normal larvae rates at the time of oocyte collection (70.2 ± 8.4% fertilized oocytes, 66.7 ± 29.4% hatched eggs and 30.3 ± 25.0% normal larvae). According to the statistical model, the water temperature that resulted in the highest fertilization rate was 25.6. °C (p<0.05). The rates of fertilization, hatching and normal larvae correlated positively (p<0.05) with one another, showing that these parameters can be used in the measurement of oocyte quality. Artificial fertilization of oocytes is recommended immediately after collection; if storage is necessary, it should be carried out at 15. °C. © 2011 Elsevier B.V.

Karyotypic diversity and evolutionary trends in the neotropical catfish genus Hypostomus lacépède, 1803 (Teleostei, Siluriformes, Loricariidae)

The family Loricariidae with 813 nominal species is one of the largest fish families of the world. Hypostominae, its more complex subfamily, was recently divided into five tribes. The tribe Hypostomini is composed of a single genus, Hypostomus Lacépède, 1803, which exhibits the largest karyotypic diversity in the family Loricariidae. With the main objective of contributing to a better understanding of the relationship and the patterns of evolution among the karyotypes of Hypostomus species, cytogenetic studies were conducted in six species of the genus from Brazil and Venezuela. The results show a great chromosome variety with diploid numbers ranging from 2n=68 to 2n=76, with a clear predominance of acrocentric chromosomes. The Ag-NORs are located in terminal position in all species analyzed. Three species have single Ag-NORs (Hypostomus albopunctatus (Regan, 1908), H. prope plecostomus (Linnaeus, 1758), and H. prope paulinus (Ihering, 1905)) and three have multiple Ag-NORs (H. ancistroides (Ihering, 1911), H. prope iheringi (Regan, 1908), and H. strigaticeps (Regan, 1908)). In the process of karyotype evolution of the group, the main type of chromosome rearrangements was possibly centric fissions, which may have been facilitated by the putative tetraploid origin of Hypostomus species. The relationship between the karyotype changes and the evolution in the genus is discussed. © Anderson Luis Alves et al.