Blood and intestinal parasites of squirrels (Rodentia: Sciuridae) in Amazonian Brazil

We report the result of an examination for blood and intestinal protozoa in 12 specimens of the red squirrel Sciurus spadiceus (Rodentia: Sciuridae) from Birroque, municipality of Placido de Castro, state of Acre, Brazil. No parasites were detected in thin, Giemsa-stained blood films of the animals, but culture of the blood of three in Difco B45 medium blood-agar slants gave rise to isolates of epimastigotes. Inoculation of one isolate into laboratory mice resulted in the appearance of Trypanosoma cruzi-like trypomastigotes in their peripheral blood, and the other two isolates gave rise to transient infections with a T. lewisi-like parasite in inoculated mice and hamsters. The failure of the latter parasite to develop in the triatomine bug Rhodnius robustus suggests that it is probably not T. rangeli. This appears to be the first record of a T. lewisi-like trypanosome in neotropical squirrels. Oocysts of an Eimeria sp., were detected in the faeces of 10 animals (83.3%). The parasite develops in the epithelial cells of the intestine, where it may cause severe damage and sometimes results in death of the animal. No oocysts were detected in bile.     

Cocaine Treatment Causes Early and Long-Lasting Changes in Muscarinic and Dopaminergic Receptors

1. The study of changes that persist after drug discontinuation could be fundamental to understand the mechanisms involved in craving and relapse. 2. In this work the changes occurring in muscarinic, D1- and D2-like receptors after 30 min (immediate), 1 day (early), 5 and 30 days (late) withdrawal periods were studied, in the striatum of rats treated once a day for 7 days with cocaine 20 and 30 mg/kg, i.p. 3. Binding assays were performed in 10% homogenates and ligands used were [3H]-N-methylscopolamine, [3H]-SCH 23390, and [3H]-spiroperidol for muscarinic (M1 + M2-like), D1-, and D2-like receptors, respectively. 4. Muscarinic receptors presented a downregulation at all doses and discontinuation times, while the dissociation constant (Kd) for this receptor decreased after 30 min, 5 and 30 days abstinence times. In relation to D1-like receptors we found an antagonistic effect with 100% increase in receptor number 30 min after the last cocaine injection, but after 1-day withdrawal a downregulation was observed with both doses that persisted up to 30 days, only with the higher dose. The dissociation constant value (Kd) for this receptor showed a decrease only with 5 and 30 days withdrawal. An increase occurred with D2-like receptors at all doses and withdrawal periods studied, while Kd increased in 30-min, 5, and 30 days withdrawal. 5. In this work we found that the subchronic cocaine treatment produces early and long-lasting modifications in cholinergic muscarinic as well in dopaminergic receptors that persist up to 30 days of cocaine withdrawal.     

Sexual mimicry in Mormolyca ringens (Lindl.) Schltr. (Orchidaceae: Maxillariinae)

BACKGROUND AND AIMS: Pollination through sexual mimicry, also known as pseudocopulation, has been suggested to occur in some genera of the Neotropical orchid subtribe Maxillariinae. However, it has been demonstrated so far only for Trigonidium obtusum. This study reports and illustrates pollination through sexual mimicry in Mormolyca ringens. METHODS: A total of 70 h were dedicated to the observation of flowers and pollinator behaviour, which was photographically recorded. Flower features involved in pollinator attraction were studied using a stereomicroscope and by SEM analyses. Preliminary observations on the plant breeding system were made by manually self-pollinating flowers. The chemical composition of the fragrance volatiles was determined by GC/MS analysis. KEY RESULTS: The flower features of M. ringens parallel those of other pseudocopulatory flowers. The labellum shape and indument are reminiscent of an insect. Sexually excited drones of Nannotrigona testaceicornis and Scaptotrigona sp. (both in the Apidae: Meliponini) attempt copulation with the labellum and pollinate the flower in the process. In both bee species, the pollinarium is attached to the scutellum. Pollinator behaviour may promote some degree of self-pollination, but preliminary observations indicate that M. ringens flowers are self-incompatible. Flowers are produced all the year round, which ties in with the production of bee males several times a year. The phylogenetic relationships of M. ringens are discussed and a number of morphological and phenological features supporting them are reported. CONCLUSIONS: It is expected that further research could bring to light whether other Maxillariinae species are also pollinated through sexual mimicry. When a definitive and robust phylogeny of this subtribe is available, it should be possible to determine how many times pseudocopulation evolved and its possible evolutionary history.     

Asynchronous meiosis in an interspecific hybrid of <Emphasis Type="Italic">Brachiaria ruziziensis</Emphasis> and <Emphasis Type="Italic">B. brizantha</Emphasis>

Male meiosis is generally synchronous in higher plants. The regulation of the cell cycle is still not well understood, and a powerful tool for gaining an understanding of this regulation is the development of mutations that affect cell-cycle synchrony. We report here asynchronous microsporogenesis in an interspecific hybrid between two important tropical grasses. In young spikelets of the interspecific hybrid 49.10% of anther meiocytes entered meiosis, exhibiting typical phases of the first and second divisions, while the other 50.90% showed distinctive features of early prophase. In older spikelets, anthers containing mature pollen grains also displayed meiocytes still undergoing meiosis. At this time, the latter cells were enclosed by the exine wall. Despite asynchrony, all cells completed meiosis. Old anthers contained only pollen grains that appeared to be in the same stage of development. Pollen fertility was estimated to be 52.76% in dehiscent anthers. An independent genetic control for meiosis synchrony and meiotic stages is suggested.     

Structural basis for APPTPPPLPP peptide recognition by the FBP11WW1 domain

WW domains are small protein-protein interaction modules that recognize proline-rich stretches in proteins. The class II tandem WW domains of the formin binding protein 11 (FBP11) recognize specifically proteins containing PPLPp motifs as present in the formins that are involved in limb and kidney development, and in the methyl-CpG-binding protein 2 (MeCP2), associated with the Rett syndrome. The interaction involves the specific recognition of a leucine side-chain. Here, we report on the novel structure of the complex formed by the FPB11WW1 domain and the formin fragment APPTPPPLPP revealing the specificity determinants of class II WW domains.     

Quantification of carvedilol in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry: application to bioequivalence study

A rapid, sensitive and specific method to quantify carvedilol in human plasma using metoprolol as the internal standard (IS) is described. The analyte and the IS were extracted from plasma by liquid-liquid extraction using a diethyl-ether solvent. After removed and dried the organic phase, the extracts were reconstituted with a fixed volume of acetonitrile-water (50/50; v/v). The extracts were analyzed by a high performance liquid chromatography coupled to electrospray tandem mass spectrometry (HPLC-MS/MS). Chromatography was performed isocratically on Alltech Prevail C18 5 microm analytical column, (150 mm x 4.6 mm i.d.). The method had a chromatographic run time of 3.5 min and a linear calibration curve over the range 0.1-200 ng ml(-1) (r2>0.997992). The limit of quantification was 0.1 ng ml(-1). This HPLC-MS/MS procedure was used to assess the bioequivalence of two carvedilol 25 mg tablet formulations (carvedilol test formulation from Laboratórios Biosintética Ltda and Coreg from Roche Químicos e Farmacêuticos S.A standard reference formulation). A single 25 mg dose of each formulation was administered to healthy volunteers. The study was conducted using an open, randomized, two-period crossover design with a 2-week wash-out interval. Since the 90% CI for C(max) and AUCs ratios were all inside the 80-125% interval proposed by the US Food and Drug Administration Agency, it was concluded that carvedilol formulation elaborated by Laboratórios Biosintética Ltda is bioequivalent to Coreg formulation for both the rate and the extent of absorption.     

Genotoxic effects of rotenone on cultured lymphocytes

Rotenone is a heterocyclic compound widely used as an insecticide, acaricide and piscicide. Its toxicity is mainly caused by the inhibition of mitochondrial respiratory processes and ATP production, resulting in the generation of reactive oxygen species. Reactive oxygen species can interact with DNA, RNA and proteins, leading to cell damage, followed by death. We used the Comet assay, and we analyzed chromosome aberrations, in order to evaluate the genotoxic and clastogenic effects of rotenone on the different phases of the cell cycle. Cultured human lymphocytes were treated with 1.0, 1.5 and 2.0 microg/mL rotenone during the G1, G1/S, S (pulses of 1 and 6 h), and G2 phases of the cell cycle. Rotenone induced DNA damage and was clastogenic, but the clastogenicity was detected only with treatments conducted during the G1/S and S phases of the cell cycle. Rotenone also induced endoreduplication and polyploidy in treatments made during G1, while it significantly reduced the mitotic index in all phases of the cell cycle.     

An agent-based system for re-annotation of genomes

Genome annotation projects can produce incorrect results if they are based on obsolete data or inappropriate models. We have developed an automatic re-annotation system that uses agents to perform repetitive tasks and reports the results to the user. These tasks involve BLAST searches on biological databases (GenBank) and the use of detection tools (Genemark and Glimmer) to identify new open reading frames. Several agents execute these tools and combine their results to produce a list of open reading frames that is sent back to the user. Our goal was to reduce the manual work, executing most tasks automatically by computational tools. A prototype was implemented and validated using Mycoplasma pneumoniae and Haemophilus influenzae original annotated genomes. The results reported by the system identify most of new features present in the re-annotated versions of these genomes.     

A critical appraisal on AIT in childhood asthma

Abstract

Allergen immunotherapy (AIT) is the only disease-modifying treatment approved for allergic rhinitis and allergic asthma and represents a suitable therapeutic option, especially in childhood, to modify the progression of respiratory allergic diseases. Starting from the previous “generic class effect” evaluation, as testified by the numerous meta analyses, AIT is now considered a product-specific pathogenic-oriented treatment.

Background

AIT was empirically proposed more than one century ago in the subcutaneous form (SCIT), but the IgE-mediated mechanism of allergy was elucidated only after 50 years of clinical use of the treatment. The sublingual administration (SLIT) was developed during the 1980 ties, to achieve an improvement in safety and convenience. While SCIT is approved in the United States for the treatment of asthmatic patients with more than 12 years, so far few trials evaluated the clinical efficacy and safety of SLIT in children with allergic asthma, although the indications and some aspects remain unclear. Certainly, due to compliance problems, the age below 3 years may be reasonably considered a practical contraindication.

Conclusions

Given that some specific AIT products are effective and approved as drugs (AIFA, EMA, FDA), the use in children is still debated. Some aspects still need robust confirm: (a) the safety of AIT in asthma; (b) the optimal regimen of administration; (c) the role of AIT as preventative treatment for asthma development.