A summit of cladistics: abstracts of the 27th Annual Meeting of the Willi Hennig Society and VIII Reunión Argentina de Cladística y Biogeografía

The 27th meeting of the Willi Hennig Society was held at the Sierras de San Javier, Tucumán (27–31 October 2008), jointly with the VIII Reunión Argentina de Cladística y Biogeografía. This was the second Hennig meeting held in South America and the third in Latin America. The event was attended by 129 participants from 16 countries, with the strongest presence from Argentina, USA and Brazil. As pointed out in the minutes of previous meetings, student participation is a good measure of the health of a society, and by this measure, the Hennig society is doing very well. For this meeting, 64 of the participants (50%) were students, 40 of which had authored or co‐authored a talk or poster. The schedule was intense, with 98 presentations (67 talks and 31 posters). The sessions consisted of contributed papers, and five symposia on diverse topics: Large Scale Analyses of Large Chunks of Life, Molecular Systematics, Latin American Biogeography in the 21st Century, Methodology, and Botanical Phylogenetics (each of the symposia, except the “green” one, had two or three student speakers). As is usual at these meetings, the atmosphere was informal and relaxed, with much discussion and debate (although the biogeographic symposium took first place for the heat of its exchanges). The Student Award Committee (Lone Aagesen, Dan Janies and Gitte Petersen) selected Santiago Catalano for the Hennig Award (‘The optimization of landmark data: a three‐dimensional approach’), Prashant Sharma for the Brundin Award (‘Phylogenetic analysis of Sandokanidae (Arachnida, Opiliones, Laniatores): Evaluating the independence of associated gene regions’), and Sebastian Barrionuevo for the Rosen Award (‘Continuous characters in a phylogenetic analysis of the frog genus Telmatobius’). In addition to the logistics and funding provided by the Willi Hennig Society, the event was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas, Fundación Miguel Lillo, Instituto Superior de Entomología ‘Dr Abraham Willink’, and the Agencia Nacional de Promoción Científica y Tecnológica.
© The Willi Hennig Society 2009.     

PKC delta and NADPH oxidase in retinoic acid-induced neuroblastoma cell differentiation

The role of reactive oxygen species (ROS) in the regulation of signal transduction processes has been well established in many cell types and recently the fine tuning of redox signalling in neurons received increasing attention. With regard to this, the involvement of NADPH oxidase (NOX) in neuronal pathophysiology has been proposed but deserves more investigation. In the present study, we used SH-SY5Y neuroblastoma cells to analyse the role of NADPH oxidase in retinoic acid (RA)-induced differentiation, pointing out the involvement of protein kinase C (PKC) delta in the activation of NOX. Retinoic acid induces neuronal differentiation as revealed by the increased expression of MAP2, the decreased cell doubling rate, and the gain in neuronal morphological features and these events are accompanied by the increased expression level of PKC delta and p67^phox, one of the components of NADPH oxidase. Using DPI to inhibit NOX activity we show that retinoic acid acts through this enzyme to induce morphological changes linked to the differentiation. Moreover, using rottlerin to inhibit PKC delta or transfection experiments to overexpress it, we show that retinoic acid acts through this enzyme to induce MAP2 expression and to increase p67^phox membrane translocation leading to NADPH oxidase activation. These findings identify the activation of PKC delta and NADPH oxidase as crucial steps in RA-induced neuroblastoma cell differentiation.     

Automated solvent artifact removal and base plane correction of multidimensional NMR protein spectra by AUREMOL-SSA

Strong solvent signals lead to a disappearance of weak protein signals close to the solvent resonance frequency and to base plane variations all over the spectrum. AUREMOL-SSA provides an automated approach for solvent artifact removal from multidimensional NMR protein spectra. Its core algorithm is based on singular spectrum analysis (SSA) in the time domain and is combined with an automated base plane correction in the frequency domain. The performance of the method has been tested on synthetic and experimental spectra including two-dimensional NOESY and TOCSY spectra and a three-dimensional ¹H,¹³C-HCCH-TOCSY spectrum. It can also be applied to frequency domain spectra since an optional inverse Fourier transformation is included in the algorithm.     

Physical mapping of rDNA genes corroborates allopolyploid origin in apomictic Brachiaria brizantha

Brachiaria (Trin.) Griseb belongs to the family Poaceae, and within the genus, apomixis or sexuality is present in different accessions of the same species. The majority of Brachiaria species are polyploid and apomictic, making strategies for crop improvement by breeding very intricate. In spite of the high frequency of apomictic polyploids, the relationship of polyploidy and hybridization with apomixis in Brachiaria is still unclear. Further analysis requires detailed knowledge regarding the genomic composition of the polyploids. The present work introduces the use of fluorescent in situ hybridization (FISH) into cytogenetic analysis of Brachiaria. Physical mapping of heterologous rDNA sequences, associated with conventional karyotyping of the B. brizantha diploid sexual (BRA 002747) and the tetraploid apomictic (BRA000591) accessions, provided evidence of the latter being of allopolyploid origin. Based on our results and on previous knowledge on apomixis in B. brizantha, we suggest that the origin of apomixis was probably a consequence of hybridization.     

Characterization of endocytic compartments after holo-high density lipoprotein particle uptake in HepG2 cells

Holo-high density lipoprotein (HDL) particle uptake, besides selective lipid uptake, constitutes an alternative pathway to regulate cellular cholesterol homeostasis. In the current study, the cellular path of holo-HDL particles was investigated in human liver carcinoma cells (HepG2) using combined light and electron microscopical methods. The apolipoprotein moiety of HDL was visualized with different markers: horseradish peroxidase, colloidal gold and the fluorochrome Alexa⁵⁶⁸, used in fluorescence microscopy and after photooxidation correlatively at the ultrastructural level. Time course experiments showed a rapid uptake of holo-HDL particles, an accumulation in endosomal compartments, with a plateau after 1–2 h of continuous uptake, and a clearance 1–2 h upon replacement by unlabeled HDL. Correlative microscopy, using HDL-Alexa⁵⁶⁸-driven diaminobenzidine (DAB) photooxidation, identified the fluorescent organelles as DAB-positive multivesicular bodies (MVBs) in the electron microscope; their luminal contents but not the internal vesicles were stained. Labeled MVBs increased in numbers and changed shapes along with the duration of uptake, from polymorphic organelles with multiple surface domains and differently shaped protrusions dominating at early times of uptake to compact bodies with mainly tubular appendices and densely packed vesicles after later times. Differently shaped and labeled surface domains and appendices, as revealed by three dimensional reconstructions, as well as images of homotypic fusions indicate the dynamics of the HDL-positive MVBs. Double staining visualized by confocal microscopy, along with the electron microscopic data, shows that holo-HDL particles after temporal storage in MVBs are only to a minor degree transported to lysosomes, which suggests that different mechanisms are involved in cellular HDL clearance, including resecretion.     

Preliminary characterization of some Streptomyces species isolated from a composting process and their antimicrobial potential

The aim of this study was to screen Streptomycetes isolates with antimicrobial and antiviral activity, in a search for new metabolites. The isolates were obtained from a composting process, and identified based on morphological characteristics and molecular biological methods. The antimicrobial activity was determined using the double-layer agar method against 53 test organisms (bacteria, yeasts, and filamentous fungi). All isolates were grown in submerged culture, in mineral salts-starch-casein (SC) broth and ISP2 media, and the filtrate cultures were used in the assays for antibacterial and antiviral activity. Bovine Herpes virus (BoHV-I) was used for the antiviral activity. The morphological and molecular characteristics confirmed that all 25 isolates belonged to the genus Streptomyces. In the assay for antimicrobial activity, 80% of the Streptomyces isolates were able to inhibit at least one of the test organisms. Of these, 80% were active against bacteria and 45% against fungi. Eight of the isolates showed a broad spectrum of inhibitory activity; of these, the isolate Streptomyces spp. 1S was able to inhibit 46 of the test organisms, and, most importantly, the 16 Gram-negative strains were inhibited. Of the 25 isolates, 44.4% of the isolates were able to grow and produce bioactive metabolites when grown in submerged culture. Four extracts showed a cytopathic effect in 10 CCID₅₀ MDBK cell, even though no viricidal effect was observed. The results obtained with these isolates indicated good biotechnological potential of these Streptomyces strains.     

Identification of potent ITK inhibitors through focused compound library design including structural information

A series of novel compound libraries inhibiting interleukin-2 inducible T cell kinase (ITK) were designed, synthesized and evaluated. In the first design cycle two library scaffolds were identified showing low micromolar inhibition of ITK. Further iterative design cycles including crystal structure information of ITK and structurally related kinases led to the identification of indolylindazole and indolylpyrazolopyridine compounds with low nanomolar ITK inhibition.     

The development of benzimidazoles as selective rho kinase inhibitors

Rho Kinase (ROCK) is a serine/threonine kinase whose inhibition could prove beneficial in numerous therapeutic areas. We have developed a promising class of ATP-competitive inhibitors based upon a benzimidazole scaffold, which show excellent potency toward ROCK (IC₅₀ <10 nM). This report details the optimization of selectivity for ROCK over other related kinases such as Protein kinase A (PKA).     

Macrocyclic BACE-1 inhibitors acutely reduce Aβ in brain after po application

A series of macrocyclic peptidic BACE-1 inhibitors was designed. While potency on BACE-1 was rather high, the first set of compounds showed poor brain permeation and high efflux in the MDRI–MDCK assay. The replacement of the secondary benzylamino group with a phenylcyclopropylamino group maintained potency on BACE-1, while P-glycoprotein-mediated efflux was significantly reduced and brain permeation improved. Several compounds from this series demonstrated acute reduction of Aβ in human APP-wildtype transgenic (APP51/16) mice after oral administration.