Positive IgG Western blot for Borrelia burgdorferi in Colombia.

In order to evaluate the presence of specific IgG antibodies to Borrelia burgdorferi in patients with clinical manifestations associated with Lyme borreliosis in Cali, Colombia, 20 serum samples from patients with dermatologic signs, one cerebrospinal fluid (CSF) sample from a patient with chronic neurologic and arthritic manifestations, and twelve serum samples from individuals without clinical signs associated with Lyme borreliosis were analyzed by IgG Western blot. The results were interpreted following the recommendations of the Centers for Diseases Control and Prevention (CDC) for IgG Western blots. Four samples fulfilled the CDC criteria: two serum specimens from patients with morphea (localized scleroderma), the CSF from the patient with neurologic and arthritic manifestations, and one of the controls. Interpretation of positive serology for Lyme disease in non-endemic countries must be cautious. However these results suggest that the putative "Lyme-like" disease may correlate with positivity on Western blots, thus raising the possibility that a spirochete genospecies distinct from B. burgdorferi sensu stricto, or a Borrelia species other than B. burgdorferi sensu lato is the causative agent. Future work will focus on a survey of the local tick and rodent population for evidence of spirochete species that could be incriminated as the etiologic agent.     

Examining monophyly in a large radiation of Madagascan butterflies (Lepidoptera: Satyrinae: Mycalesina) based on mitochondrial DNA data

The satyrine butterfly subtribe Mycalesina has undergone one of the more spectacular evolutionary radiations of butterflies in the Old World tropics. Perhaps the most phenotypically pronounced diversification of the group has occurred in the Malagasy region, where 68 currently recognized species are divided among five genera. Here, we report the results of phylogenetic analyses of sequence data from the cytochrome c oxidase II and cytochrome b mitochondrial genes, for a total of 54 mycalesine taxa, mostly from Madagascar. These molecular data complement an existing data set based on male morphological characters. The molecular results support the suggestion from morphology that three of the five Malagasy genera are paraphyletic and support the monophyly of at least three major morphological clades. Novel hypotheses of terminal taxon pairs are generated by the molecular data. Dense taxon sampling appears to be crucial for elucidating phylogenetic relationships within this large radiation. A potentially complex scenario for the origin of Malagasy mycalesines is proposed.     

Synthesis and activity of novel benzoxazole derivatives of mannopeptimycin glycopeptide antibiotics

A series of benzoxazole derivatives of the mannopeptimycin glycopeptide antibiotics was synthesized via a novel benzoxazole formation reaction by treating aminophenol of mannopeptimycin-beta with an aldehyde and DDQ in DMF. Some of these derivatives (e.g., 5b, 5d, 5m, and 7b) showed good activity against Gram-(+) bacteria when compared to the parent compound mannopeptimycin-beta.     

MicroRNA fate upon targeting with anti-miRNA oligonucleotides as revealed by an improved Northern-blot-based method for miRNA detection

MicroRNAs (miRNAs) are small non-coding RNAs involved in fine-tuning of gene regulation. Antisense oligonucleotides (ONs) are promising tools as anti-miRNA (anti-miR) agents toward therapeutic applications and to uncover miRNA function. Such anti-miR ONs include 2'-O-methyl (OMe), cationic peptide nucleic acids like K-PNA-K3, and locked nucleic acid (LNA)-based anti-miRs such as LNA/DNA or LNA/OMe. Northern blotting is a widely used and robust technique to detect miRNAs. However, miRNA quantification in the presence of anti-miR ONs has proved to be challenging, due to detection artifacts, which has led to poor understanding of miRNA fate upon anti-miR binding. Here we show that anti-miR ON bound to miR-122 can prevent the miRNA from being properly precipitated into the purified RNA fraction using the standard RNA extraction protocol (TRI-Reagent), yielding an RNA extract that does not reflect the real cellular levels of the miRNA. An increase in the numbers of equivalents of isopropanol during the precipitation step leads to full recovery of the targeted miRNA back into the purified RNA extract. Following our improved protocol, we demonstrate by Northern blotting, in conjunction with a PNA decoy strategy and use of high denaturing PAGE, that high-affinity anti-miRs (K-PNA-K3, LNA/DNA, and LNA/OMe) sequester miR-122 without causing miRNA degradation, while miR-122 targeting with a lower-affinity anti-miR (OMe) seems to promote degradation of the miRNA. The technical issues explored in this work will have relevance for other hybridization-based techniques for miRNA quantification in the presence of anti-miR ONs.     

Isospora araponga sp. n. (Apicomplexa: Eimeriidae), a new species of Isospora Schneider from a bare-throated bellbird, Procnias nudicollis (Vieillot, 1817) (Passeriformes: Cotingidae) from Brazil

Faecal samples from a couple of bare-throated bellbirds Procnias nudicollis imported from Brazil to Barcelona Zoo contained oocysts of Isospora araponga n. sp. Sporulated oocysts were subspherical to broadly ellipsoidal, 19.5 (17-22) x 15.5 (14-16.5) microm, shape index (length:width ratio) 1.26 (1.13-1.38) with smooth and colourless bilayered wall, about 1 microm thick, and with varying number (1-3) of polar granule, but without a micropyle or residuum. The sporocysts were ellipsoidal, slightly asymmetric, 12.5 (12-13) x 8.5 (7.5-9) microm with barely visible Stieda body and indistinguishable substieda body. Sporozoites were elongated, possessing smooth surface and two distinct refractile bodies.     

Venous endothelium reactivity to Angiotensin II: A study in primary endothelial cultures of rat vena cava and portal vein

The role of the vascular endothelium in modulating the arterial system has been widely investigated, but poorly explored at the venous site. In the present work, primary cultures of venous endothelium from rat Vena Cava (VC) and Portal Vein (PV) were established, characterized and analyzed according to their growth pattern and ability to produce nitric oxide (NO) and prostanoids (PGF_{2 α} and PGI₂), at basal state and after stimulation with Angiotensin II (Ang II, 1 μmol/L). Basal NO was detected in all examined cells in culture. Pre-incubation with Ang II increased NO production in cells from VC (but not in PV cultures), through activation of both AT₁ and AT₂ receptors. Both cultures exhibited detectable levels of PGF_{2 α} at resting conditions, which were similarly enhanced by Ang II. Basal PGI₂ levels were higher in PV, but increased after Ang II treatment in VC, with no further effect on PV cells. We conclude that endothelial cells from VC and PV exhibit important properties and react to Ang II, probably influencing the whole circulatory system. This experimental cell model gives support to further studies concerning intracellular pathways of the venous endothelium, analyzed in separate from the vascular smooth muscle wall.     

Pollen size evolution: correlation between pollen volume and pistil length in Asteraceae

Based on the assumptions that pollen tube length is predetermined by provisions in the pollen and that it is a function of pistil length, I hypothesise that species with longer pistils will have larger pollen grains than species with shorter pistils, and that pistil length and pollen size will be positively correlated in a linear manner. To test this hypothesis, the relationship between pollen grain volume and pistil length was compared in 43 Asteraceae species from Argentina. A positive linear correlation was found between pollen volume and pistil length. This correlation remained significant even after potential effects of phylogenetic relatedness were removed. The maintenance of this correlation suggests that in Asteraceae the association between pistil length and pollen volume may reflect a functional rather than a phyletic relationship. In addition, the pistil length: pollen volume ratio (PPR) was analysed in relation to the phylogenetic position of the species. High values of PPR would imply a reduction of the male gametophyte in relation to the minimal volume that a pollen grain must have to grow and fertilise an ovule. Thus, the general pattern of pollen volume reduction in relation to pistil length previously found among many angiosperm families will be also present within a family, i.e., PPR values of derived Asteraceae would be higher than those of basal species. Results indicated that reduction of pollen volume in derived Asteraceae was three times greater than the concomitant shortening of pistil length. Consequently, PPR increased with the phylogenetic position of the taxa. This work supports the correlation between pistil and pollen characters previously found for other plant families and confirms the influence of post-pollination processes on pollen size evolution. Received: 4 November 1999 / Revision accepted: 14 February 2000