Short communication: Chromosome description and localization of nucleolus organizing regions (NORs) by Ag-staining technique in Alburnus filippii (Cyprinidae, Cypriniformes) in Anzali Lagoon, north Iran

The silver staining procedure is commonly used to visualize the activity of ribosomal RNA genes, since it has been established that only those NORs of metaphase chromosomes that are functionally active during the preceding interphase are capable of staining. Nucleolus organizer regions (NORs) are used as markers to indicate intra- and inter-species chromosomal polymorphism in many groups of fish. There are no available reports specifying the activity of nucleolus organizer regions location in Kura bleak (A. filippii) chromosomes by silver staining. The aim of this paper is to present the chromosome complement, number and location of the nucleolar organizer regions (NORs) of A. filippii (Kessler, 1877), commonly known as Kura bleak from northern Iran, a survey initiated by Gul and others. The samples (six females and four males) were collected in 2006 from Anzali Wetland (37º28'N, 49º27'E) Guilan, Iran

A checklist of chromosome numbers and karyotypes of Amazonian freshwater fishes

Une liste des nombres de chromosomes de 211 espèces de poisson du bassin amazonien est présentée. Ces espèces, appartenant à 5 ordres, sont caractérisées par une grande variabilité du nombre de chromosomes (2n = 22 à 2n = 134), par la présence de chromosomes sexuels et de polymorphisme chromosomique chez certaines espèces, et enfin par une grande spécificité des bandes C et des sites des régions de l'organisateur du nucléole. (Résumé d'auteur

Profile of micronucleus frequencies and DNA damage in different species of fish in a eutrophic tropical lake

Lake Paranoá is a tropical reservoir for the City of Brasilia, which became eutrophic due to inadequate sewage treatment associated with intensive population growth. At present, two wastewater treatment plants are capable of processing up to 95% of the domestic sewage, thereby successfully reducing eutrophization. We evaluated both genotoxic and cytotoxic parameters in several fish species (Geophagus brasiliensis, Cichla temensis, Hoplias malabaricus, Astyanax bimaculatus lacustres, Oreochromis niloticus, Cyprinus carpio and Steindachnerina insculpita) by using the micronucleus (MN) test, the comet assay and nuclear abnormality assessment in peripheral erythrocytes. The highest frequencies of MN were found in Cichla temensis and Hoplias malabaricus, which were statistically significant when compared to the other species. However, Steindachnerina insculpita (a detritivorous and lake-floor feeder species) showed the highest index of DNA damage in the comet assay, followed by C. temensis (piscivorous). Nuclear abnormalities, such as binucleated, blebbed, lobed and notched cells, were used as evidence of cytotoxicity. Oreochromis niloticus followed by Hoplias malaricus, ominivorous/detritivotous and piscivorous species, respectively, presented the highest frequency of nuclear abnormalities, especially notched cells, while the herbivorous Astyanax bimaculatus lacustres showed the lowest frequency compared to the other species studied. Thus, for biomonitoring aquatic genotoxins under field conditions, the food web should also be considered

A checklist of chromosome numbers and karyotypes of Amazonian freshwater fishes

Une liste des nombres de chromosomes de 211 espèces de poisson du bassin amazonien est présentée. Ces espèces, appartenant à 5 ordres, sont caractérisées par une grande variabilité du nombre de chromosomes (2n = 22 à 2n = 134), par la présence de chromosomes sexuels et de polymorphisme chromosomique chez certaines espèces, et enfin par une grande spécificité des bandes C et des sites des régions de l'organisateur du nucléole. (Résumé d'auteur