Aluminum induces changes in oxidative burst scavenging enzymes in Coffea arabica L. suspension cells with differential Al tolerance

The accumulation of reactive oxygen species (ROS) and concomitant oxidative stress have been considered deleterious consequences of aluminum toxicity. However, several lines of evidence suggest that ROS can function as important signaling molecules in the plant defense system for protection from abiotic stress and the acquisition of tolerance. The role of ROS-scavenging enzymes was assayed in two different coffee cell suspension lines. We treated L2 (Al-sensitive) and LAMt (Al-tolerant) Coffea arabica suspension cells with 100 μM AlCl₃ and observed significant differences in catalase activity between the two cell lines. However, we did not observe any differences in superoxide dismutase or glutathione reductase activity in either cell line following Al treatment. ROS production was diminished in the LAMt cell line. Taken together, these results indicate that aluminum treatment may impair the oxidative stress response in L2 cells but not in LAMt cells. We suggest a possible role for Al-induced oxidative bursts in the signaling pathways that lead to Al resistance and protection from Al toxicity.     

Transgressive character expression in hybrid zones between the native invasives Tithonia tubaeformis and Tithonia rotundifolia (Asteraceae) in Mexico

Natural hybridization frequently promotes gene introgression among closely related species in sympatric populations, producing complex patterns of morphological variation. Therefore, a detailed understanding of the dynamics of interspecific gene flow and its morphological patterns is of widespread interest. We tested if introgressive hybridization promotes an increase in transgressive characters in comparison with the parental species. A sunflower species complex occurring in Mexico formed by two native invasive species, Tithonia tubaeformis and Tithonia rotundifolia, was analyzed using 46 morphological characters (leaf, flower and fruit) in five hybrid zones (N = 150 individuals) and two pure sites for each parental species (N = 80 individuals). In general, T. tubaeformis differed significantly from T. rotundifolia in all the examined characters, except six foliar and one inflorescence character. Morphological characters support the hypothesis of hybridization in this complex, even though both species remain morphological distinct in mixed stands. Individual hybrids appear to be a mosaic of parent-like (24.8 % of traits), intermediate (26.1 %) and transgressive (37.8 %) phenotypes (the remaining 11.3 % of the traits did not differ significantly from both parental species). Our results suggest that individuals from the same parental species were more similar among themselves than to putative hybrids, indicating occasional hybridization with segregation in hybrid types or backcrossing to parents. Evidence indicates a unidirectional pattern of gene flow toward T. rotundifolia.     

Molecular and morphometric systematics of Diapterus (Perciformes,Gerreidae)

The fish belonging to Gerreidae are common representatives of the coastal ichthyofauna of the tropics and subtropics of the world. The genus Diapterus has a neotropical distribution and currently includes four species: two in the Atlantic Ocean [Irish mojarra D. auratus Ranzani 1842 and rhombic mojarra D. rhombeus (Cuvier 1829)] and two in the Pacific Ocean [short‐beaked mojarra D. brevirostris (Sauvage 1879) and golden mojarra D. aureolus (Jordan & Gilbert 1882)]. This genus has uncertain taxonomy based on the remarkable and dissimilar morphology of D. aureolus. We evaluated the taxonomy and phylogeny of Diapterus with statistical (canonical discriminant analysis) and phylogenetic analyses (maximum parsimony, maximum likelihood and Bayesian inference) of geometric morphometric data (relative warps) and molecular data (12Sr RNA, 16Sr RNA, COI and RAG1 sequences). Our results indicate that the genus Diapterus as we currently conceive it is a polyphyletic group: [(Gerres cinereus – Eucinostomus spp. (D. aureolus – (Eugerres spp. (D. auratus – (D. brevirostris – D. rhombeus)))))]. Therefore, a taxonomic rearrangement is needed. To preserve the monophyly of the group, our proposal is to remove D. aureolus and place it in a new monotypic genus. A neotype is designated for D. aureolus as well as an artificial identification key for the genera and the species treated in this article.     

“de novo” trisomy 1q32→1qter and monosomy 3p25→3pter

Summary The syndrome of familial lymphedema (type Meige) with distichiasis was observed in father and son. The association with uvula bifida and submucous cleft of the palate is described for the first time.     

Electrophoretic and immunological characterization of pollen protein ofZea mays races

Electrophoretic and serological studies with proteins extracted from the pollen of 12 races of maize (Zea mays) have proved valuable in distinguishing among these races. Both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and double immunodffusion (Ouchterlony method) were used to analyze the extracted pollen proteins. Jaccard's similarity coefficient was calculated from the data generated by 2-state scoring of the band patterns obtained in each system. Average linkage cluster analysis of the similarity matrices was used to construct phenograms illustrating the similarity among the extracts. The racial groupings indicated in these pheno grams, when compared with those of several morphological studies, show some general agreement. However, there are differences, the most notable being that Chalqueno appeared the most dissimilar of the races studied and that Dulce showed high similarity to Palomero Toluqueño, rather than being an exceptional race as it is usually considered. The possible bearing of the groupings of the races in these phenograms with respect to genetic lineage and selection of maize is discussed.