Use of High-Performance Liquid Chromatography-Mass Spectrometry of Adipose Tissue for Detection of Bioaccumulation of Pyriproxyfen in Adults of Lithobates catesbeianus.

The aims of the study were: (i) evaluate the efficacy of using amphibian adipose tissue as a valid biomarker of water contaminated by pyriproxyfen; and (ii) verify the use of Lithobates catesbeianus in laboratory experiments as a potential bioindicator for bioaccumulation of pesticide in adipose tissue from amphibians. Adult frogs were exposed to different dilutions (0.002 g/L and 0.02 g/L) of Sumilarv® (pyriproxyfen) over 50 days. The average results of the fortified sample were 108%, indicating that the test method was effective. Adult frogs exposed to the standard dose recommended by the World Health Organization (WHO) showed bioaccumulation of pyriproxyfen in adipose tissue significantly higher than control animals. Lithobates catesbeianus proved to be an effective bioindicator and the adipose tissue was an efficient biomarker to bioaccumulation of pyriproxyfen. We conclude that high-performance liquid chromatography-mass spectrometry was effective measuring pyriproxyfen bioaccumulation in adult amphibians.

Instability of Multiple Sex Chromosomes Systems in Fish: The Case of Erythrinus erythrinus (Bloch & Schneider, 1801) (Characiformes, Erythrinidae).

The fish species Erythrinus erythrinus belongs to the family Erythrinidae (order Characiformes, superorder Teleostei) and is considered a species complex because of the considerable differences between the karyotypes of analyzed populations. Whereas some populations present a sex chromosome system with male heterogamety, others do not show differentiated sex chromosomes. In this article, two novel karyotypes of E. erythrinus with the occurrence of male and female heterogamety are described, and a discussion of the stability of multiple sex chromosome systems is provided. A possible cause for sex chromosomes instability is that the Robertsonian rearrangements that originated the multiple systems did not prevent recombination with ancestral chromosomes, which also did not pass through a heterochromatinization process, the opposite of what usually happens with simple systems, especially of the ZZ/ZW or XX/XY type. It is suggested that multiple sex chromosome systems would not act as an effective postzygotic barrier, especially when there are hybridization zones between distinct karyomorphs that bear and that do not bear sex chromosome systems, allowing the generation of hybrids. This finding is important both for the comprehension of sex chromosomes evolution in fish and for conservation biology since the contact between populations with and without multiple sex chromosomes may compromise the regional biodiversity.

Basic cytogenetics and physical mapping of 5S and 18S ribosomal genes in Hoplias malabaricus (Osteichthyes, Characiformes, Erythrinidae) from isolated natural lagoons: a conserved karyomorph along the Iguaçu river basin.

Erythrinidae include Neotropical teleost fish that are widely distributed in South America. Hoplias Gill, 1903 include two large groups: H. malabaricus Bloch, 1794 and H. lacerdae Miranda Ribeiro, 1908. Hoplias malabaricus is characterized by remarkable karyotype diversity, with some karyomorphs widely distributed geographically while others are more restricted to certain river basins. Cytogenetic analyzes were performed in a population of Hoplias malabaricus from the Wildlife Refuge of Campos de Palmas, the Iguaçu River basin. The specimens showed diploid number of 42 chromosomes (24m+18sm) without differentiated sex chromosomes system. The impregnation by silver nitrate showed multiple AgNORs. Seven pairs (4, 7, 10, 13, 16, 20 and 21) carrying 18S rDNA were detected by FISH. Heterochromatin was verified in the centromeric and pericentromeric region of most chromosomes and the terminal region of some pairs. FISH with 5S rDNA probes showed two chromosome pairs carrying these sites in the interstitial region (8 and 14). The data obtained in this study are similar to those found for two other populations of H. malabaricus already studied in the basin of the Iguaçu River, confirming the hypothesis that this species is natural, not having been introduced, as well as having an intrinsic characteristic, such as the largest number of sites of 18S rDNA.

Pigmentation in anuran testes: anatomical pattern and variation.

In amphibians, pigmented cells are present in several organs, composing an extracutaneous pigmentary system. Seventeen species from two families were studied to develop a protocol for pigmentary classification. The amount and distribution of these cells are variable, allowing the establishment of anatomical patterns for visceral pigmentation in anuran testes.