A prime inference on genetic diversity (RAPDs) in the marine fish Atherinella brasiliensis (Teleostei,Atherinopsidae) from Southern Brazil

Da Silva Cortinhas, M. C., Glienke, C., Prioli, A. J., Noleto, R. B., Matoso, D. A. and Cestari, M. M. 2010. A prime inference on genetic diversity (RAPDs) in the marine fish Atherinella brasiliensis (Teleostei, Atherinopsidae) from Southern Brazil. —Acta Zoologica (Stockholm) 91 : 242–248 As a result of the importance of Atherinella brasiliensis in estuarine environments, random amplified polymorphic DNA (RAPD) markers were used to verify the genetic diversity in A. brasiliensis from two different places in Paranaguá Bay (Paraná State) and one from the Conceição Lagoon (Santa Catarina State). Cytogenetic data have shown a high karyotypic diversity in some populations, although in others this peculiarity demonstrates rearrangements such as heterochromatinization. In the present study, a low level of genetic structuring between the samples from Conceição Lagoon compared with the others was observed through principal coordinate analysis (PCO), analysis of molecular variance and Mantel test according to 79 RAPD markers. As this specie does not perform horizontal migration and the individuals of Conceição Lagoon are isolated, three hypotheses are proposed to explain the results: (i) similar environments may show homogeneous populations not depending on the geographical distance, (ii) because vicariant events that formed the bays occurred in a recent period, the fragmentation effects over the structuring of the genetic diversity may still be low and not totally detectable by the RAPD technique and (iii) the isolation time or the number of generations may not be enough to promote a possible differentiation and genetic structuring between the specimens of these three places. The specimens of these places present a low level of differentiation and genetic structuring so we can consider them as a unique homogeneous population.     

Bioprospecting of <Emphasis Type="Italic">Diaporthe terebinthifolii</Emphasis> LGMF907 for antimicrobial compounds

Antibiotic-resistant bacteria have been observed with increasing frequency over the past decades, driving the search for new drugs and stimulating the interest in natural products sources. Endophytic fungi from medicinal plants represent a great source of novel bioactive compounds useful to pharmaceutical and agronomical purposes. Diaporthe terebinthifolii is an endophytic species isolated from Schinus terebinthifolius, a plant used in popular medicine for several health problems. The strain D. terebinthifolii LGMF907 was previously reported by our group to produce secondary metabolites with biological activity against phytopathogens. Based on these data, strain LGMF907 was chosen for bioprospecting against microorganisms of clinical importance and for characterization of major secondary metabolites. In this study, different culture conditions were evaluated and the biological activity of this strain was expanded. The crude extracts demonstrated high antibacterial activity against Escherichia coli, Micrococcus luteus, Saccharomyces cerevisiae, methicillin-sensitive Staphylococcus aureus, and methicillin-resistant S. aureus. The compounds diaporthin and orthosporin were characterized and also showed activity against the clinical microorganisms evaluated. This study discloses the first isolation of diaporthin and orthosporin from D. terebinthifolii, and revealed the potential of this endophytic fungus to produce secondary metabolites with antimicrobial activity.     

Regional heterogeneity of EGFR gene amplification and nuclear morphology in glioblastomas. An investigation using laser microdissection and pressure catapulting

OBJECTIVE: To study the regional heterogeneity of epidermal growth factor receptor (EGFR) gene amplification (EGFR-GA) in glioblastomas, considering the relationship between this mutation and morphology of tumor cell nuclei. STUDY DESIGN: Tissue samples gained by laser microdissection and pressure catapulting were used for the performance of differential polymerase chain reaction in 32 morphologically different regions from 7 glioblastomas. Semiquantitative determination of EGFR expression and image analysis of tumor cell nuclei were performed in the same regions. RESULTS: Distinct regional differences concerning the degree of EGFR-GA were found in 2 tumor cases. When comparing regions with different degrees of gene amplification within these cases, morphologic differences in tumor cell nuclei were observed. The other tumor cases also showed distinct intratumoral heterogeneity concerning histomorphology but no regional heterogeneity in the degree of EGFR-GA. When comparing regions with a low densitometric EGFR/interferon (INF) band ratio (< 2.19, n = 18) and a high EGFR/IFN band ratio (> 4.39, n = 14), the latter type of region showed a significantly higher percentage of Ki-67--positive tumor cell nuclei and lower values for several shape variables (Fourier amplitudes), indicating a tendency toward a more regular nuclear shape in regions with distinct EGFR-GA. For the EGFR/IFN band ratio, a significant correlation was found with several morphometric variables, especially those of nuclear shape and distances between nuclei. CONCLUSION: In glioblastomas showing regional heterogeneity in the degree of EGFR-GA, morphology of tumor cell nuclei has been shown to be different when comparing regions with different degrees of EGFR-GA. Glioblastomas may also show distinct regional heterogeneity of histomorphology without evidence of regional heterogeneity of EGFR-GA. A significant statistical association has been confirmed between the degree of EGFR-GA and quantitative morphology of tumor cell nuclei.     

Human SPRY2 inhibits FGF2 signalling by a secreted factor

Growth factor signalling pathways and their inhibitors coordinate the formation of three-dimensional patterns of vertebrates and invertebrates. Temporal and spatial restriction of the response to a few well-defined cells is crucial and needs the integration of positive and negative signals. Recently, Spry has been identified as an inhibitor of fibroblast growth factor (FGF) signalling during Drosophila trachea development. Spry has been described as an intracellular protein that can exert its function in a cell autonomous or a paracrine manner. Here we describe the role of SPRY2, a human homologue of Spry, in human FGF2 signalling. We show that in primary human dermal endothelial cells (MVEC) SPRY2 mRNA is transiently upregulated in response to FGF2. Overexpression of SPRY2 in A375 cells leads to the secretion of a soluble factor that inhibits FGF2- but not VEGF-stimulated proliferation of MVEC. Direct administration of recombinant SPRY2 protein has no effect on MVEC proliferation. However, SPRY2 protein binds the intracellular adaptor protein GRB2, indicating an intracellular localization. A SPRY2/GFP fusion protein remains in the cell, further supporting the intracellular localization of SPRY2. So the intracellular protein SPRY2 is involved in the non-cell autonomous inhibitory effect indirectly, via regulating the secretion of an inhibitor of FGF2 signalling in vertebrates, the evidence of which is presented here for the first time.     

EGFR gene amplification in glioblastomas. Is there a relationship with morphology of tumor cell nuclei and proliferative activity?

OBJECTIVE: To confirm a relationship between histomorphology of glioblastomas and amplification of the gene for the epidermal growth factor receptor (EGFR) as the most important molecular biologic alteration in these tumors. STUDY DESIGN: In paraffin sections of surgical specimens from 71 primary resected glioblastomas, tumor cell nuclei in the region with the highest proliferative activity (Ki-67 immunostaining) were investigated morphometrically. Shape variables (roundness factor, Fourier amplitudes) and nuclear area were measured. Additionally, the numerical density of Ki-67-positive tumor cell nuclei was estimated. Differential polymerase chain reaction (PCR) was performed from paraffin sections of the same tumor area. The signals for the EGFR gene and IFN gamma reference gene were quantified densitometrically. RESULTS: Cases with distinct EGFR gene amplification (EGFR/IFN ratios > 5) revealed significantly lower mean values for several Fourier amplitudes, indicating a more regular nuclear shape when compared with cases without evidence of EGFR gene amplification (EGFR/IFN-ratios < or = 1). The Ki-67 index and nuclear area showed no significant differences between these groups. Although a large variation in nuclear morphology was observed for cases without evidence of EGFR gene amplification, discriminant analysis based on morphometric variables provided a good separation of these cases from cases with distinct EGFR gene amplification, with a high percentage of statistically correct reclassified cases. CONCLUSION: Our results provide evidence of a relationship between genetic alterations and histomorphology of glioblastomas.     

Bioprospecting highly diverse endophytic Pestalotiopsis spp. with antibacterial properties from Maytenus ilicifolia, a medicinal plant from Brazil

Thirteen endophytic fungal strains of the genus Pestalotiopsis were isolated from the medicinal plant Maytenus ilicifolia Mart. ex. Reiss (commonly known as "espinheira santa") and their antimicrobial properties were investigated. Two isolates were successful in inhibiting the growth of the tested microorganisms (Escherichia coli, Klebsiella pneumoniae, Micrococcus luteus, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA)) using the technique of bioautographic thin-layer chromatography (TLC) agar overlay assay. An analysis based on a polyphasic approach integrating taxonomic information, morphological traits, RAPD markers, and the sequencing of the ITS1-5.8S-ITS2 of the rDNA led to the assignment of the isolates as belonging to the species Pestalotiopsis microspora, Pestalotiopsis vismiae, and Pestalotiopsis leucothoes. Therefore, the present study presents a new approach to the study of endophytic fungi of the genus Pestalotiopsis.