Pest and disease control in blackcurrants and apples by the use of overhead irrigation sprinklers

In field experiments on the effectiveness of overhead irrigation spraying of crop protection chemicals, an oscillating bar sprinkler was compared with hand spraying in post-harvest applications of protective fungicides mancozeb (0.096% a.i.) with zineb (0.022% a.i.) for the control of blackcurrant leaf spot, Pseudopeziza ribis. Twin-jet rotating sprinkler nozzles were compared with conventional automatic spraying of Cox's Orange Pippin apple trees in the application of a malathion emulsion (0.125% a.i.) for the control of apple-grass aphid, Rhopalosiphum insertum and also in applications of pre-blossom dodine emulsion (0.03% a.i.) and post-blossom captan suspension (0.09% a.i.) for control of apple scab, Venturia inaequalis. All applications were made at a nominal rate of 2250 litres/ha (200 gal/acre). On blackcurrants, the hand spraying gave much better control of leaf spot and was shown by fluorescent tracer assessment to give more cover on the lower surfaces of the leaves than the sprinkler. On apple, the rotating sprinklers gave almost as good control of apple-grass aphid and apple scab as the conventional automatic spraying. The malathion deposit levels, determined by g.l.c., on the flower trusses were also comparable, though the liquid volume distribution from the irrigation nozzles was uneven.     

Amplification of ribosomal DNA of Anoplocephalidae: Anoplocephala perfoliata diagnosis by PCR as a possible alternative to coprological methods

The diagnosis of tapeworm infections in horses relies on copro-diagnostic methods, which are time-consuming and of limited sensitivity for determination of the exact prevalence. The development of serological tests has slightly improved the detection of tapeworm infections, but more sensitive methods are still required. A polymerase chain reaction (PCR)-based approach may constitute a valuable tool to improve tapeworm diagnosis. Nuclear ribosomal DNA (rDNA) is a useful target for species and/or strain markers. Partial 18S, the internal transcribed spacer 1 (ITS-1), the 5.8S, the internal transcribed spacer 2 (ITS-2), and partial 28S rDNA of the equine tapeworms Anoplocephala perfoliata and Anoplocephaloides mamillana were amplified and sequenced. The lengths and GC contents of the regions sequenced were 2087-2091bp and 49.35-49.69% for A. perfoliata, and 2110-2119bp and 49.15-49.32% for A. mamillana, respectively. Sequence alignment and comparison of both taxa showed 79.3-80.2% identity. The lowest identities were found in the ITS regions with 39.9-43.5% for the ITS-1 and 59.5-61.2% for the ITS-2. No matches of the ITS-2 of A. perfoliata and A. mamillana were found with other species by BLAST search. For this reason, ITS-2 sequences seemed appropriate as accurate species markers and A. perfoliata ITS-2 primers were developed. The ITS-2 PCR enabled the detection of genomic DNA as low as 0.5 pgs. First efforts on the practical application of the PCR-based approach were made. A 6-mg fragment of a tapeworm proglottid was detected in 0.5 and 1g of faeces.     

Heterogeneous pathological outcomes after experimental pH1N1 influenza infection in ferrets correlate with viral replication and host immune responses in the lung

The swine-origin pandemic (p) H1N1 influenza A virus causes mild upper-respiratory tract disease in most human patients. However, some patients developed severe lower-respiratory tract infections with fatal consequences, and the cause of these infections remain unknown. Recently, it has been suggested that different populations have different degrees of susceptibility to pH1N1 strains due to host genetic variations that are associated with inappropriate immune responses against viral genetic characteristics. Here, we tested whether the pathologic patterns of influenza strains that produce different disease outcomes in humans could be reproduced in a ferret model. Our results revealed that the severities of infection did not correspond to particular viral isolate and were not associated with the clinical phenotypes of the corresponding patients. Severe pathological outcomes were associated with higher viral replication, especially in alveolar areas, and with an exacerbated innate cellular immune response that was characterised by substantial phagocytic and cytotoxic cell migration into the lungs. Moreover, detrimental innate cellular responses were linked to the up-regulation of several proinflammatory cytokines and chemokines and the down-regulation of IFNα in the lungs. Additionally, severe lung lesions were associated with greater up-regulations of pro-apoptotic markers and higher levels of apoptotic neutrophils and macrophages. In conclusion, this study confirmed that the clinicopathological outcomes of pH1N1 infection in ferrets were not only due to viral replication abilities but also depended on the hosts’ capacities to mount efficient immune responses to control viral infection of the lung.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-014-0085-8) contains supplementary material, which is available to authorized users.     

Transmission of equine influenza virus to dogs

Molecular and antigenic analyses of three influenza viruses isolated from outbreaks of severe respiratory disease in racing greyhounds revealed that they are closely related to H3N8 equine influenza virus. Phylogenetic analysis indicated that the canine influenza virus genomes form a monophyletic group, consistent with a single interspecies virus transfer. Molecular changes in the hemagglutinin suggested adaptive evolution in the new host. The etiologic role of this virus in respiratory disease was supported by the temporal association of rising antibody titers with disease and by experimental inoculation studies. The geographic expansion of the infection and its persistence for several years indicate efficient transmission of canine influenza virus among greyhounds. Evidence of infection in pet dogs suggests that this infection may also become enzootic in this population.     

Heterodimeric GTPase core of the SRP targeting complex

Two structurally homologous guanosine triphosphatase (GTPase) domains interact directly during signal recognition particle (SRP)-mediated cotranslational targeting of proteins to the membrane. The 2.05 angstrom structure of a complex of the NG GTPase domains of Ffh and FtsY reveals a remarkably symmetric heterodimer sequestering a composite active site that contains two bound nucleotides. The structure explains the coordinate activation of the two GTPases. Conformational changes coupled to formation of their extensive interface may function allosterically to signal formation of the targeting complex to the signal-sequence binding site and the translocon. We propose that the complex represents a molecular "latch" and that its disengagement is regulated by completion of assembly of the GTPase active site.     

Overview of historical and paleoecological studies of acidic air pollution and its effects

Historical evidence of acid deposition and its effects which was presented at Muskoka, Ontario in September, 1985 is summarized. This evidence consists of written records of the past chemistry and biology of atmospheric, terrestrial, and aquatic systems; it also includes evidence from archived collections which were “revisited”, from tree rings, and from the chemical and biological “records” in lake sediment and peat from which histories of airborne contaminants and ecosystem responses to these contaminants were inferred.     

Optimizing the precision of toxicity threshold estimation using a two-stage experimental design

An important consideration for risk assessment is the existence of a threshold, i.e., the highest toxicant dose where the response is not distinguishable from background. We have developed methodology for finding an experimental design that optimizes the precision of threshold model parameter estimation for single-chemical threshold experiments. Being interested in precisely estimating the threshold parameter, we used the D-optimality and the D _s-optimality criteria. The D-optimal design results in parameter estimates as precise as possible in the sense that the likelihood-based confidence region has minimum volume, while the D _s-optimal threshold design results in parameter estimates as precise as possible in that the variance of the threshold parameter estimate is minimized. For nonlinearmodels, optimal designs are a function of the unknown parameters via the information matrix. Therefore, estimates of the parameters must be obtained before the optimal design of the experiment can be found. For this reason, a two-stage D-D _s-optimal design is recommended where the D-optimality criterion is used in the first stage followed by the D _s-optimality criterion in the second stage. The first stage is used for range finding and to obtain good global estimates to supply to the second stage. The second stage results in precise parameter estimates with minimum variance for the threshold parameter estimate. We propose that the use of this two-stage D-D _s-optimal design will provide toxicologists with the experimental parameters necessary to accurately estimate thresholds for risk assessment purposes in a more cost-effective and timely manner.     

Acid-base analysis of dissolved organic matter in surface waters

A mono-protic multi-site model is developed to obtain a pK(acid) — concentration distribution. Dense and equal interval pH data are required for an accurate characterization. A computer driven titrimetric system is used to obtain the data. The technique is applied to dissolved organic carbon (> 15 mg C L^-1) samples from the Kejimkujik region, Nova Scotia. A calculation shows that the acidic (pH=4.6) dystrophic waters can result from mixing 15 mg C L^-1 of the organic acids with an initial inorganic system of about 75 peq L^-1 alkalinity.     

Determination of flunixin in edible bovine tissues using liquid chromatography coupled with tandem mass spectrometry

An accurate, reliable, and reproducible assay was developed and validated to determine flunixin in bovine liver, kidney, muscle, and fat. The overall recovery and percent coefficient of variation (%CV) of twenty-eight determinations in each tissue for flunixin free acid were 85.9% (5.9% CV) for liver, 94.6% (9.9% CV) for kidney, 87.4% (4.7% CV) for muscle, and 87.6% (4.4% CV) for fat. The theoretical limit of detection was 0.1 microg/kg (ppb, ng/g) for liver and kidney, and 0.2 ppb for muscle and fat. The theoretical limit of quantitation was 0.3, 0.2, 0.6, and 0.4 ppb for liver, kidney, muscle, and fat, respectively. The validated lower limit of quantitation was 1 ppb for edible tissues with the upper limit of 400 ppb for liver and kidney, 100 ppb for fat, and 40 ppb for muscle. Accuracy, precision, linearity, specificity, ruggedness, and storage stability were demonstrated. Briefly, the method involves an initial acid hydrolysis, followed by pH adjustment ( approximately 9.5) and partitioning with ethyl acetate. A portion of the ethyl acetate extract was purified by solid-phase extraction using a strong cation exchange cartridge. The eluate was then evaporated to dryness, reconstituted, and analyzed using LC/MS/MS. The validated method is sensitive and specific for flunixin in edible bovine tissue.