A Comovirus Infecting Rocket (Eruca sativa) in Brazil

A virus related to Radish mosaic virus and Turnip ringspot virus (TuRSV) was found infecting rocket plants in Brazil. Predicted amino acids from partial viral RNA sequences placed it closer to TuRSV. We describe here the identification and partial characterization of the first comovirus found infecting a crucifer species in Brazil.     

Evaluation of the floral vasculature of the Janusia,Mascagnia and Tetrapterys species as a tool to explain the decrease of floral organs in Malpighiaceae

The family Malpighiaceae is considered monophyletic, but the intra-family classification is conflicting. Analyses of floral vasculature allow the identification of reductions, connations and adnations and can even reveal evolutionary steps prior to current floral morphology. The present work analysed the floral vasculature of Janusia mediterranea, Mascagnia cordifolia and Tetrapterys chamaecerasifolia using material processed by traditional methods for light microscopy. A general pattern was observed of three bundle traces supplying each sepal and one trace per petal and stamen; Mascagnia is an exception, as its eglandular sepal has only a median trace but shares lateral traces with adjacent sepals. No dorsal traces are emitted to the carpels; however, three intercarpellary complexes are emitted that divide into six ventral bundles, supplying the ovule. Mascagnia demonstrates connation between the anterior and adjacent sepal glands; reductions of the anterior sepal glands were registered in Tetrapterys and Janusia. This work reveals two distinct processes for gland loss in non-related groups of the family that resulted in similar present appearances. Our evaluation of the number of calyx glands and the processes of glandular loss in species with less than ten glands improves our understanding of the evolution of calyx glands in Malpighiaceae.     

Occult hepatitis B virus infection among injecting drug users in the Central-West Region of Brazil

The prevalence of occult hepatitis B virus (HBV) infection was investigated in 149 hepatitis B surface antigen (HBsAg) negative injecting drug users (IDUs) in the Central-West Region of Brazil. Of these individuals, 19 were positive for HBV DNA, resulting in an occult HBV infection prevalence of 12.7% (19/149); six of these 19 individuals had anti-HBV core and/or anti-HBV surface antibodies and 13 were negative for HBV markers. All IDUs with occult hepatitis B reported sexual and/or parenteral risk behaviours. All HBV DNA-positive samples were successfully genotyped. Genotype D was the most common (17/19), followed by genotype A (2/19). These findings reveal a high prevalence of occult HBV infection and the predominance of genotype D among IDUs in Brazil''s Central-West Region.     

Propagation of the loud “tchó” call of golden-backed uakaris, Cacajao melanocephalus, in the black-swamp forests of the upper Amazon

Arboreal primates use loud vocalisations to transmit information in densely vegetated habitats. These vocalisations are likely to show adaptations to increase their propagation and to transmit information. Golden-backed uakaris, Cacajao melanocephalus, emit a loud vocalization termed the “tchó” call, which seems to function as a contact call and encodes information on the individual signaler and behavioural context. Because the call is often used for communication over relatively large distances, we were interested in its propagation in the wild. The aim of the present study was to investigate the degradation patterns of the tchó call in the flooded igapó forest. We examined via playback experiments how the acoustic parameters of this call changed with increasing distance from the playback speaker. We broadcast 12 tchó calls and rerecorded them along a transect at distances of 10, 20, 40, 80 and 160?m from the speaker in two igapó forest patches in Jaú National Park, Amazonas, Brazil. At 160?m from the speaker, the tchó call degraded in both patches and was barely recordable. Up to a distance of 80?m, the bandwidth and number of harmonics in the call decreased with increasing distance, while the lowest frequency increased. The highest frequency (HF) did not gradually decrease with increasing distance. However, when we compared the HF at distances of 10 and 80?m, we could see a clear decrease in this parameter. Call duration increased compared with the broadcast signal up to 40?m because of reverberation, but decreased at 80?m as the weaker echoes of the call attenuated. These changes may reveal information about the signaler’s distance during signal transmission. The frequency of maximum energy (FME) of the tchó call decreased significantly when comparing recordings made at 10 and 80?m. Nevertheless, it did not show a consistent and gradual decrease with increasing rerecording distance (at least up to 80?m). FME remained relatively stable (±50?Hz on average, at least up to 80?m) when compared to the other call parameters, suggesting that the tchó call may be adapted to transmit information with some efficiency throughout the igapó forest.     

Diet of the thin-spined porcupine (Chaetomys subspinosus), an Atlantic forest endemic threatened with extinction in southeastern Brazil

Chaetomys is a poorly known, monotypic genus of tree porcupine threatened with extinction due to deforestation and habitat fragmentation. Its nocturnal habit, relatively restricted distribution and low level of activity have conspired for decades against detailed field studies. Here the diet of the species in restinga forests is described for the first time. Restinga is a subtype of lowland Atlantic forest occurring on sandy soils close to the Atlantic littoral in Brazil. Three radio-collared females were monitored for 12 months between March 2005 and February 2006. Leaves were the most heavily consumed dietary item, varying from 71.9% to 75.4% of the diet of each individual, followed by flowers (7.7% - 15.7%) and fruits (0 - 1.4%). Animals fed on 57 trees from 14 species, with a higher concentration on Pera glabrata (49.8%) and Tapiriria guianensis (22.7%). Pera glabrata is locally abundant and widely distributed in the Atlantic forest. Each individual consumed a smaller subset of plant species (4-10 species/individual) and shared only the two most important tree species (P. glabrata and T. guianensis). Results corroborate previous studies indicating that Chaetomys is a folivore, perhaps the most folivorous amongst the Erethizontidae. Since the most consumed plant species are relatively common and widespread, Chaetomys might thrive in a broader range of habitats than previously suspected, including secondary forests.     

EGF receptor signaling in prostate morphogenesis and tumorigenesis.

The growth and differentiation of the prostate gland are largely dependent on extracellular signaling factors. In addition to androgens, many polypeptide growth factors function through autocrine or paracrine networks. The paracrine interaction between stromal and epithelial cells is critical for androgen regulation, morphogenesis, epithelial cell proliferation, and secretory differentiation. Efforts to identify the essential growth factors and studies on their effects have been prompted by the fact that prostate cells in culture need substances other than androgens for proliferation. In this context, transforming growth factor-alpha and epidermal growth factor, among others, have been studied extensively. Recent advances have suggested that these EGF receptor (EGFR) ligands play roles not only during glandular development but also during neoplastic transformation and tumor progression. The cell responses most relevant to the role of this receptor signaling are both mitogenesis and cell motility. The aim of the review is to provide an overview of current knowledge about EGFR and its ligands in the organogenesis and tumorigenesis of the prostate gland.     

Genotoxic evaluation of the River Paranaíba hydrographic basin in Monte Carmelo,MG, Brazil,by the Tradescantia micronucleus

Pollutants have adverse effects on human health and on other organisms that inhabit or use water resources. The aim of the present study was to assess the environmental quality of three watercourses in Monte Carmelo, MG, Brazil, using the micronucleus test on Tradescantia. For each treatment, 15 plants were exposed to water samples for 24 h. The control group was exposed to formaldehyde (0.2%) and the negative control to Hoagland solution. Subsequently the plants were placed in Hoagland solution for 24 h to recover. Cells were stained with 2% acetic carmine and examined by light microscopy. Three hundred tetrads were analyzed per slide. The frequency of genotoxic alterations was expressed as the number of micronuclei per 100 tetrads, and the groups were compared by ANOVA. At all sample sites for each watercourse significant genotoxicity indices were observed. The results suggest that in the Mumbuca creek, the current situation of effluent discharge should be reconsidered by the municipal environmental authorities. The increase in micronucleus frequency denoted for water samples of the Mumbuca creek, Lambari river and Perdizes river emphasizes the need to adopt environmental vigilance strategies, such as biological monitoring.     

Predation by the tayra on the common marmoset and the pale-throated three-toed sloth

Predation on arboreal mammals is rarely observed in the wild. Here we describe the first confirmed observations of predation on a juvenile wild common marmoset (Callithrix jacchus) and on a neonate wild pale-throated three-toed sloth (Bradypus tridactylus) by the mustelid carnivore Eira barbara, the tayra. We discuss predation on both of the prey species and review the nature of predation by the tayra.