The molecular phylogeny of the sea star Echinaster (Asteroidea: Echinasteridae) provides insights for genus taxonomy

In this study, we used sequences of two mitochondrial genes, cytochrome c oxidase I (COI) and 16S rRNA, and one nuclear gene, 28S rRNA, to test the monophyly of the sea star genus Echinaster, and understand the phylogenetic relationships among species and subgenera within this genus. Phylogenetic analyses based on Bayesian inference and maximum likelihood methods revealed three clades with high values of genetic divergence among them (K2P distances for COI over 23%). One of the clades grouped all Echinaster (Othilia) species, and the other two clades included Echinaster (non‐Othilia) species and Henricia species, respectively. Although the relationships among Henricia, Othilia, and Echinaster could not be completely clarified, the Othilia clade was a well‐supported group with shared diagnostic morphological characters. Moreover, the approximately unbiased test applied to the phylogenetic reconstruction rejected the hypothesis of the genus Echinaster as a monophyletic group. According to these results, we suggest the revalidation of Othilia as a genus instead of a subgenus within Echinaster. Our study clarifies important points about the phylogenetic relationships among species of Echinaster. Other important systematic questions about the taxonomic classification of Echinaster and Henricia still remain open, but this molecular study provides bases for future research on the topic.     

Storage elicits a fast antioxidant enzyme activity in <Emphasis Type="Italic">Araucaria angustifolia</Emphasis> embryos

Storage of recalcitrant seeds leads to the initiation of subcellular damage or to the initiation of germination process, and both may result in viability loss. This study aimed to elucidate the biochemical basis of embryos survival of Araucaria angustifolia recalcitrant seeds during storage. After harvesting, seeds were stored at ambient conditions (without temperature and humidity control) and in a cold chamber (temperature of 10 ± 3 °C, and relative humidity of 45 ± 5 %). Moisture content, viability, H₂O₂ content, lipid peroxidation, protein content, and activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), at 0, 15, 45 and 90 days of storage, were evaluated. Seed viability reduced about 40 % during the storage period accompanied by a reduction in soluble protein (about 64 % of reduction) in both storage conditions, and increased lipid peroxidation (about 115 % and 66 % for ambient and cold chamber conditions, respectively). H₂O₂ content used as a marker of oxidative stress was reduced during the period, possibly controlled by the action of CAT and APX, for which increased activities were observed. The results allowed the identification of seven SOD isoenzymes (one Mn-SOD, five Fe-SOD and one Cu/Zn-SOD), whose activities also increased in response to storage. Some biochemical damage resulting from storage was observed, but viability reduction was not due to failure of enzymatic protection mechanisms.     

Antifungal Pisum sativum defensin 1 interacts with Neurospora crassa cyclin F related to the cell cycle

Plant defensins, components of the plant innate immune system, are cationic cysteine-rich antifungal peptides. Evidence from the literature [Thevissen, K., et al. (2003) Peptides 24, 1705-1712] has demonstrated that patches of fungi membrane containing mannosyldiinositolphosphorylceramide and glucosylceramides are selective binding sites for the plant defensins isolated from Dahlia merckii and Raphanus sativus, respectively. Whether plant defensins interact directly or indirectly with fungus intracellular targets is unknown. To identify physical protein-protein interactions, a GAL4-based yeast two-hybrid system was performed using the antifungal plant peptide Pisum sativum defensin 1 (Psd1) as the bait. Target proteins were screened within a Neurospora crassa cDNA library. Nine out of 11 two-hybrid candidates were nuclear proteins. One clone, detected with high frequency per screening, presented sequence similarity to a cyclin-like protein, with F-box and WD-repeat domains, related to the cell cycle control. GST pull-down assay corroborated in vitro this two-hybrid interaction. Fluorescence microscopy analysis of FITC-conjugated Psd1 and DAPI-stained fungal nuclei showed in vivo the colocalization of the plant peptide Psd1 and the nucleus. Analysis of the DNA content of N. crassa conidia using flow cytometry suggested that Psd1 directed cell cycle impairment and caused conidia to undergo endoreduplication. The developing retina of neonatal rats was used as a model to observe the interkinetic nuclear migration during proliferation of an organized tissue from the S toward the M phase of the cell cycle in the presence of Psd1. The results demonstrated that the plant defensin Psd1 regulates interkinetic nuclear migration in retinal neuroblasts.     

Measurement of 4,5-dioxovaleric acid by high-performance liquid chromatography and fluorescence detection

In this work we describe a sensitive method for the detection of 4,5-dioxovaleric acid (DOVA). 4,5-Dioxovaleric acid is derivatized with 2,3-diaminonaphthalene to form 3-(benzoquinoxalinyl-2)propionic acid (BZQ), a product with favorable UV absorbance and fluorescence properties. The high-performance liquid chromatographic method with UV absorbance and fluorescence detection is simple and its detection limit is approximately 100 fmol. This method was used to detect 4,5-dioxovaleric acid formation during metal-catalyzed 5-aminolevulinic acid (ALA) oxidation. Iron and ferritin were active in the formation of 4,5-dioxovaleric acid in the presence of 5-aminolevulinic acid. In addition, HPLC–MS–MS assay was used to characterize BZQ. The determination of 4,5-dioxovaleric acid is of great interest for the study of the mechanism of the metal-catalyzed damage of biomolecules by 5-aminolevulinic acid. This reaction may play a role in carcinogenesis after lead intoxication. The high frequency of liver cancer in acute intermittent porphyria patients may also be due to this reaction.     

Overall survival in women with breast cancer: the influence of pepsinogen C gene polymorphism

We aimed to study the role of an insertion/deletion polymorphism in the Pepsinogen C (PGC) gene in the clinical outcome of 172 breast cancer patients. The six polymorphic alleles were amplified using PCR. Our results indicate that patients carrying the allele 6 present a higher 5-year survival mean (83.4% of 6 allele carriers were alive at 5 years vs. only 68.6% of noncarriers, p=0.001), suggesting a role for this polymorphism in the outcome of breast cancer patients. We hypothesize that PGC polymorphism can be a predictive biomarker in breast cancer, contributing to an individual profile of great interest in clinical oncology.