Leucine-tRNA initiates at CUG start codons for protein synthesis and presentation by MHC class I

Effective immune surveillance by cytotoxic T cells requires newly synthesized polypeptides for presentation by major histocompatibility complex (MHC) class I molecules. These polypeptides are produced not only from conventional AUG-initiated, but also from cryptic non-AUG-initiated, reading frames by distinct translational mechanisms. Biochemical analysis of ribosomal initiation complexes at CUG versus AUG initiation codons revealed that cells use an elongator leucine-bound transfer RNA (Leu-tRNA) to initiate translation at cryptic CUG start codons. CUG/Leu-tRNA initiation was independent of the canonical initiator tRNA (AUG/Met-tRNA(i)(Met)) pathway but required expression of eukaryotic initiation factor 2A. Thus, a tRNA-based translation initiation mechanism allows non-AUG-initiated protein synthesis and supplies peptides for presentation by MHC class I molecules.     

Accuracy assessment and screening of a dairy herd with paratuberculosis by three different ELISAs

Although the culture of Mycobacterium avium subsp. paratuberculosisis is the gold standard for the diagnosis of paratuberculosis, this bacterium is difficult to grow. In contrast, serological tests like ELISAs are inexpensive, rapid, and easy to perform. The aims of this study were to evaluate the accuracy of three different ELISAs: one with the commercial antigen PPA-3, another one with L5P (a recently described lipopentapeptide), and a third one with an in-house antigen whole cell lysates (WCL) of M. avium (MAA) strain D4ER (Study 1), and to compare them with other tests for paratuberculosis (PTB) diagnosis (Study 2). In Study 1, the sensitivities of the three ELISAs tested were 74.1%, 37% and 74.1%, respectively, whereas their specificities were 98.9%, 100% and 100%, respectively. In Study 2, we compared the three above-mentioned ELISAs with the intradermal reaction test using Avian PPD (PPDa) and fecal culture associated with Ziehl-Neelsen stain and PCR tests, in a dairy herd with 4.6% of cows with clinical signs of PTB. The results showed that fecal samples from 14 cows (16%) were culture-positive and that fecal samples from nine cows (10%) were PPDa-positive. Most of these animals (culture-positive and PPDa-positive) were detected as positive with any of the three ELISAs tested. Serological results showed that 31% of the animals were positive to ELISA-PPA-3, 17% to ELISA-L5P and 42.5% to ELISA-WCL. The combination of these three ELISAs identified 50.6% of the animals as positive in the infected herd. In particular, the results show that the locally developed ELISA seems to be useful for identifying many infected animals in a herd.     

Immobilization of free-ranging maned wolf (Chrysocyon brachyurus) with tiletamine and zolazepam in central Brazil.

A tiletamine hydrochloride-zolazepam hydrochloride combination was used successfully to immobilize 27 free-ranging maned wolves (Chrysocyon brachyurus) at a mean dose of 2.77+/-0.56 (mean+/-SD) mg/kg. The induction time ranged from 3-15 min. Animals remained immobilized for periods of 48.56 +/-12.65 min. Compulsive licking, excessive salivation, muscle twitching, muscle tremors, tachypnea, and bradycardia were observed associated with the induction of the anesthesia in 13 of 27 maned wolves. Muscle twitching, pedal withdrawal reflex, muscle tremors, and ataxia were observed during recovery in three (11%) maned wolves. There were no significant differences in heart rates (P = 0.44), respiratory rates (P = 0.82), and rectal temperatures (P = 0.54) recorded at 5, 15, and 25 min after induction at these dosages. The tiletamine hydrochloride-zolazepam hydrochloride combination was shown to be an effective and safe immobilizing agent for free-ranging maned wolves.     

Genetic diversity of international bovine viral diarrhoea virus (BVDV) isolates: identification of a new BVDV-1 genetic group

In the last decade, several studies were performed to characterise bovine viral diarrhoea virus (BVDV) isolates and define genetic groups by genotyping. Much data is now available from GenBank, predominantly sequences from the 5' untranslated region (5'-UTR). In order to find out whether genetic grouping of isolates from different countries could be harmonised, 22 new isolates from five countries were analysed in combination with published sequences. Eighteen of these isolates were typed as BVDV genotype 1 (BVDV-1), and one isolate from Argentina and three isolates from Brazil were typed as BVDV-2. BVDV-1 isolates were clustered into five previously defined genetic groups: BVDV-1a, b, d, e and f. Two isolates from Finland and one from Egypt formed a group which was tentatively labelled as BVDV-1j, since statistical support was low. By using a fragment of the Npro gene for typing, we found that these isolates fall into the same group as a deer strain, and are statistically significant. Some Swiss BVDV strains taken from GenBank were found in a new genetic group which was designated as BVDV-1k. The BVDV-2 isolates included in this study seemed to fall into two genetic groups.     

Marine-Derived Penicillium purpurogenum Reduces Tumor Size and Ameliorates Inflammation in an Erlich Mice Model

Background: This study addresses the antitumoral properties of Penicillium purpurogenum isolated from a polluted lagoon in Northeastern Brazil. Methods: Ethyl Acetate Extracellular Extract (EAE) was used. The metabolites were studied using direct infusion mass spectrometry. The solid Ehrlich tumor model was used for antitumor activity. Female Swiss mice were divided into groups (n = 10/group) as follows: The negative control (CTL−), treated with a phosphate buffered solution; the positive control (CTL+), treated with cyclophosphamide (25 mg/kg); extract treatments at doses of 4, 20, and 100 mg/kg; animals without tumors or treatments (Sham); and animals without tumors treated with an intermediate dose (EAE20). All treatments were performed intraperitoneally, daily, for 15 days. Subsequently, the animals were euthanized, and the tumor, lymphoid organs, and serum were used for immunological, histological, and biochemical parameter evaluations. Results: The extract was rich in meroterpenoids. All doses significantly reduced tumor size, and the 20 and 100 mg/kg doses reduced tumor-associated inflammation and tumor necrosis. The extract also reduced the cellular infiltration of lymphoid organs and circulating TNF-α levels. The extract did not induce weight loss or renal and hepatic toxic changes. Conclusions: These results indicate that P. purpurogenum exhibits immunomodulatory and antitumor properties in vivo. Thus, fungal fermentation is a valid biotechnological approach to the production of antitumor agents.     

Agroforestry systems in the highlands of the Tehuacán Valley,Mexico: indigenous cultures and biodiversity conservation

In this study we analysed: (1) the biodiversity conservation capacity of Agroforestry Systems (AFS) in temperate highlands of the Tehuacán–Cuicatlán Valley, Central Mexico, (2) human cultural motives and actions for conserving such diversity and (3) problems endangering that capacity. We evaluated the richness and diversity of perennial plant species maintained in AFS through vegetation sampling of 14 agricultural plots and compared their composition with that of natural forests (14 plots of 500 m² each). We examined the situations among communities of Náhuatl, Ixcatec and Cuicatec people, documenting through interviews the management practices of plant species and the whole system, reasons why people maintain vegetation cover within AFS, and factors influencing changes in decisions favouring agriculture intensification. In the AFS studied we recorded a total of 79 species of trees and shrubs, 86 % of them being native species and representing 43 % of all species of trees and shrubs recorded in the sampling of the natural forests the AFS derive from. People leave standing on average a total of 40 individual trees and shrubs per agricultural plot. Reasons for leave plant species standing were more frequently associated with their use as fruit trees, firewood, shade, beauty, respect to nature and other environmental benefits. Water availability for irrigation, land tenure, and dependence on agriculture and forest for peasant's subsistence were main decision factors influencing AFS variation in their composition. AFS in temperate zones are important reservoirs of biodiversity and biocultural heritage and should be keystones for conservation policies in the Tehuacán–Cuicatlán Valley.     

Rickettsia lusitaniae sp. nov. isolated from the soft tick Ornithodoros erraticus (Acarina: Argasidae)

In this study a novel Rickettsia from the spotted fever group, isolated from Ornithodoros erraticus soft ticks collected from pigpens in the south of Portugal, is described. After initial screening revealed Rickettsia-positive ticks, isolation attempts were then performed. Successful isolates were achieved by shell-vial technique using Vero E6 cells at 28 °C. Molecular characterization of the isolate was performed based on analysis of five rickettsial genes gltA, ompA, ompB, sca1 and htr with their subsequent concatenation along with other rickettsial species resulting in a clustering of the new isolate with Rickettsia felis and Rickettsia hoogstraalii. The degree of nucleotide sequence similarity with other rickettsiae fulfills the criteria for classification of our isolate as a novel species. The name Rickettsia lusitaniae sp. nov. (= CEVDI PoTiRo) is proposed for this new species found in O. erraticus.