Chromosome polymorphism in Astyanax fasciatus (Teleostei, Characidae), Part 3: Analysis of the RAPD and ISSR molecular markers

The Randomly Amplified Polymorphic DNA (RAPD) and Inter-Simple Sequence Repeats (ISSR) molecular markers were used to complement the study of chromosomal polymorphism in Astyanax fasciatus (Teleostei, Characidae) from the Mogi-Guaçu River (Southeastern Brazil), analyzed in three collection sites along the river (Ouro Fino – MG, Cachoeira de Emas – SP and Barrinha – SP). Two cytotypes (or karyotypic types), denominated standard cytotypes, were previously characterized, one including 2n = 46 chromosomes and the other 2n = 48 chromosomes, where all the chromosomes of the complement form homologous pairs. Additionally, variant karyotypic forms with 2n = 45, 46 and 47 chromosomes were also detected, although with a lower frequency in relation to the standard cytotypes. RAPD turned out little informative in the analysis of the observed situation, indicating a high value of migrants per generation among the cytotypes. On the other hand, ISSR showed a small structure, especially among the standard cytotypes from the Barrinha region where the Nm was 0.4301 with a genetic identity of 0.6862 and genetic distance of 0.3765. However, the general results obtained do not discard the possibility of interbreeding between both standard cytotypes and/or their descendants as a source of chromosome variation. The association between the cytogenetic and molecular markers viabilized putative explanatory scenery for the origin and evolution of the forms seen in A. fasciatus.     

DNA Barcode is Efficient for Identifying Bat Species

Journal of Mammalian Evolution - Chiroptera stands out for the richness of species and a variety of unique characteristics. However, the morphological similarities in some taxa of this group can...     

Time Space Translation: A Hox Mechanism for Vertebrate A-P Patterning

The vertebrate A-P axis is a time axis. The head is made first and more and more posterior levels are made at later and later stages. This is different to the situation in most other animals, for example, in Drosophila. Central to this timing is Hox temporal collinearity (see below). This occurs rarely in the animal kingdom but is characteristic of vertebrates and is used to generate the primary axial Hox pattern using time space translation and to integrate successive derived patterns (see below). This is thus a different situation than in Drosophila, where the primary pattern guiding Hox spatial collinearity is generated externally, by the gap and segmentation genes.     

NITPICK: peak identification for mass spectrometry data

Background  

The reliable extraction of features from mass spectra is a fundamental step in the automated analysis of proteomic mass spectrometry (MS) experiments.     

PA,a stress-induced short cut to switch-on ethylene signalling by switching-off CTR1?

Constitutive triple response 1 (CTR1) is a protein kinase that represses plant responses to ethylene. Recently, we have shown that CTR1 function is negatively regulated by the lipid second messenger phosphatidic acid (PA) in vitro.¹ PA was shown to inhibit (1) CTR1''s protein kinase activity, (2) the intramolecular interaction between N-terminus and kinase domain, and (3) the interaction of CTR1 with the ethylene receptor ETR1. PA typically accumulates within minutes in response to biotic or abiotic stresses, which are known to induce ethylene formation. Although long-term treatment with ethephon does stimulate PA accumulation, our results show no fast increase in PA in response to ethylene. A speculative model is presented which explains how stress-induced PA formation could switch on downstream ethylene responses via interaction of the lipid with CTR1.Key words: lipid signaling, phosphatidic acid, ethylene, constitutive triple response 1, plant stress signaling, protein kinase, phospholipase D