Canine visceral leishmaniasis and Rhipicephalus sanguineus: evaluation and comparison of classical techniques

Veterinary Research Communications - The aim of this study was evaluating the association and correlation between the diagnostics tests used for Leishmania spp. detection in dogs and ticks. We...     

Cross-sectional study of Brucella spp. using real-time PCR from bovine whole blood in Colombia

Veterinary Research Communications - A cross-sectional study was conducted in Colombia to recover Brucella spp. DNA from bovine whole-blood samples through probe-based real-time PCR (qPCR). By an...     

Effects of soil flooding on leaf gas exchange and growth of two neotropical pioneer tree species

Schinus terebinthifolius Raddi (Anacardiaceae) and Rapanea ferruginea (Ruiz & Pavon) Mez (Myrsinaceae) are two neotropical pioneer trees with wide geographical distribution in South America, highly degree of adaptation to different soil conditions and intense regeneration in areas with anthropic activities. With the aim to recommend the use Schinus and Rapanea in gallery forest restoration programs, we conducted an experiment with the objective to analyze the capacity of these two pioneer trees to tolerate soil flooding, mainly by accessing the effects of flooding on leaf gas exchange, growth and dry matter partitioning. Seedling survival throughout the 56-day flooding period were 100 and 90% for Schinus and Rapanea, respectively. The mean values of stomatal conductance (g_s) and net photosynthesis (A) observed in the control seedlings were, respectively, 0.4 mol m^–2s^–1 and 14 mmolm^–2s^–1, for Schinus, and 0.5 mol m^–2s^–1 and 14 mmolm^–2s^–1, for Rapanea. On day 20 flooding reduced gs and A by 36 and 29% in Schinus, and 81 and 61% in Rapanea. At the end of the experiment, significant decreases were also observed for root and whole plant biomass, in both species. Based on the results, we concluded that seedlings of Schinus and Rapanea can survive and grow throughout a medium period of soil waterlogging, in spite of the alterations observed in their physiological behavior, such as the decreases in stomatal conductance and in whole plant biomass.     

Phenotypic and genotypic characterization of antimicrobial resistance in faecal enterococci from wild boars (Sus scrofa)

The objective was to study the prevalence of antimicrobial resistance and the mechanisms implicated in faecal enterococci of wild boars in Portugal. One hundred and thirty-four enterococci (67 E. faecium, 54 E. hirae, 2 E. faecalis, 2 E. durans and 9 Enterococcus spp.) were recovered from 67 wild boars (two isolates/sample), and were further analysed. High percentages of resistance were detected for erythromycin, tetracycline, and ciprofloxacin (48.5%, 44.8%, and 17.9%, respectively), and lower values were observed for high-level-kanamycin, -streptomycin, chloramphenicol, and ampicillin resistance (9%, 6.7%, 4.5%, and 3.7%, respectively). No isolates showed vancomycin or high-level-gentamicin resistance. The erm(B), tet(M), aph(3')-IIIa, and ant(6)-I genes were demonstrated in all erythromycin-, tetracycline-, kanamycin-, and streptomycin-resistant isolates, respectively. Specific genes of Tn916/Tn1545 and Tn5397 transposons were detected in 78% and 47% of our tet(M)-positive enterococci, respectively. The tet(S) and tet(K) genes were detected in one isolate of E. faecium and E. hirae, respectively. Three E. faecium isolates showed quinupristin-dalfopristin resistance and the vat(E) gene was found in all of them showing the erm(B)-vat(E) linkage. Four E. faecium isolates showed ampicillin-resistance and all of them presented seven amino acid substitutions in PBP5 protein (461Q-->K, 470H-->Q, 485M-->A, 496N-->K, 499A-->T, 525E-->D, and 629E-->V), in relation with the reference one; a serine insertion at 466' position was found in three of the isolates. Faecal enterococci from wild boars harbour a variety of antimicrobial resistance mechanisms and could be a reservoir of antimicrobial resistance genes and resistant bacteria that could eventually be transmitted to other animals or even to humans.     

Endogenous Progesterone Concentrations Affect Progesterone Release from Intravaginal Devices Used for Oestrous Synchronization in Cattle

Intravaginal progesterone‐releasing devices are largely used both as contraceptives in humans and as a component of oestrous synchronization protocols in cattle. To reduce costs in large‐scale timed artificial insemination, the reuse of these releasing devices is common. Passive hormone diffusion, however, depends on the concentration gradient, which could affect the amount of residual progesterone present in these devices after a first use. To evaluate the effect of the presence of a corpus luteum in the release of progesterone from intravaginal devices, three synchronization protocols were designed to simulate the effects of inserting the device in the early dioestrus, late dioestrus or anoestrus. Holstein‐Zebu cross‐bred heifers were randomly allocated into one of these three treatments, and a series of blood samples was taken to evaluate the plasma progesterone concentrations. After 8 days, the intravaginal devices were removed and underwent a previously validated alcoholic extraction technique to measure the residual progesterone. Non‐used devices were used as controls. As expected, the simultaneous presence of the intravaginal device and a corpus luteum resulted in increased plasma progesterone concentrations. Conversely, the amount of residual progesterone in the devices after use was inversely proportional to the plasma progesterone concentration. These results demonstrate that the release rate of progesterone from intravaginal devices is affected by the endogenous concentration of this hormone; consequently, the strategy for reuse should account for the category and expected luteal cyclic activity of the animals undergoing synchronization protocols.     

CLPP and EEA profiles of microbial communities in salt marsh sediments

Objective  Microbial communities are a central component of trophic dynamics and biogeochemical processes on coastal systems, since most of the processes in sediments are mediated by microorganisms and carried out by enzymes. Microorganisms play a key role in decomposition processes in salt marsh sediments, although the significance of microbial dynamics is largely unexplored. A culture-dependent (Ecoplate) and a culture-independent (extracellular enzyme activity [EEA]) approaches were evaluated in their ability to distinguish the catabolic potential among sediments from Tagus estuary salt marshes with different proximities to anthropogenic sources. Methods  Ecoplate was used to analyse the salt marsh community-level physiological profiles (CLPPs). Results were expressed as the net area under the curve for each of the 31 response wells over a 3-day incubation period in two sediment horizons. The catabolic profiles for salt marsh samples were analysed by Principal Component Analysis (PCA) and hierarchic clustering methods. EEA was analysed by fluorescein diacetate (FDA) hydrolysis in two sediment horizons. The FDA is catalysed by extracellular enzymes, i.e. esterases, lipases and partially by proteases. Results were expressed as μg g⁻¹d wt h⁻¹. Results and Discussion  In this study the CLPP and EEA data were not generally correlated. In Corroios salt marsh only in surface sediments higher net areas corresponded to higher extracellular enzymatic activity, and in Alcochete deep sediments lower net areas corresponded to lower enzymatic activity. Although EEA profiles more directly reflect the inherent activity of resident community in each salt marsh sample, the CLPP profiles provide better assessments of diversity. ESS-Submission Editor: Prof. Dr. Peter Schroeder, Institute of Soil Ecology, Department of Rhizosphere Biology, GSF — National Research Center for Environment & Health, Ingolstaedter Landstrasse 1, 85758 Neuherberg, Germany (peter.schroeder@gsf.de)     

Contrastant banana accessions for resistance to the burrowing nematode,based on molecular markers RAPD

This work aimed to proceed molecular characterization of seven banana accessions (Borneo, Grand Naine, 1304-06, 4249-05, 0337-02, 0323-03 and 4279-06) resistance to the nematode Radopholus similis. These accessions were selected taking in account the reproduction factor (RF) among 26 banana genotypes from a working collection belonging to Embrapa Mandioca e Fruticultura Tropical. The genomic DNA of the seven accessions was extracted, and 36 decamere primers had been used to obtain RAPD markers. The resulting markers were converted into a matrix of binary data. From that matrix the genetic distance between the accessions were estimated, for further clustering and graphic dispersion analyses. From a total of 521 RAPD markers generated, 420 (81%) were polymorphic, including 140 (27%) potentially promising for application on works related to genetic mapping of the resistance to R. similis. OPE-15, OPH-17, and OPG-09 were the primers that contributed to the highest number of bands promising for genetic mapping of resistance (12, 8, and 8, respectively). The genetic distances between accessions ranged from 0.106 to 0.455, with the longest one observed between cv. Borneo and the genotype 4279-06, considered as highly susceptible and resistant, respectively, to the nematode according to the RF. The graphic dispersion distinguished three groups of accessions, and most of resistant genotypes clustered together in the same group. The most contrastant genotypes for resistance (Borneo and 4249-05) were separated by a genetic distance of 0.374, and possessed a total of 114 polymorphic bands promising for genetic mapping of resistance. In addition, the results of pathogenicity tests were congruent with those obtained by RAPD analyses.     

Changes in pigments and plastid ultrastructure during ripening of green-fleshed and yellow-fleshed kiwifruit

Fruit of Actinidia deliciosa have green flesh when ripe, whereas fruit of Actinidia chinensis often have yellow flesh when ripe. The outer and inner pericarps of A. deliciosa fruit retain their chlorophyll during ripening. In those fruit of A. chinensis that become yellow on ripening, the colour change is caused by the disappearance of chlorophylls unmasking the yellow carotenoids already present, rather than by increased synthesis of carotenoids. In fruit of A. deliciosa and those fruit of A. chinensis that remain green, the chloroplasts retain their typical morphology during ripening, whereas in fruit of A. chinensis that become yellow during ripening the chloroplasts of the immature green fruit are transformed into fully developed chromoplasts.