Computed tomography or rhinoscopy as the first-line procedure for suspected nasal tumor: a pilot study.

There are no evidence-based guidelines as to whether computed tomography (CT) or endoscopy should be selected as the first-line procedure when a nasal tumor is suspected in a dog or a cat and only one examination can be performed. Computed tomography and rhinoscopic features of 17 dogs and 5 cats with a histopathologically or cytologically confirmed nasal tumor were retrospectively reviewed. The level of suspicion for nasal neoplasia after CT and/or rhinoscopy was compared to the definitive diagnosis. Twelve animals underwent CT, 14 underwent rhinoscopy, and 4 both examinations. Of the 12 CT examinations performed, 11 (92%) resulted in the conclusion that a nasal tumor was the most likely diagnosis compared with 9/14 (64%) for rhinoscopies. Computed tomography appeared to be more reliable than rhinoscopy for detecting nasal tumors and should therefore be considered as the first-line procedure.

Examen de première intention lors de suspicion de tumeur nasale: scanner où rhinoscopie? Une étude pilote. Lors de suspicion de tumeur nasale chez le chien et le chat, il n'existe à ce jour aucun consensus quant à l'examen de première intention à privilégier entre la tomodensitométrie et l'endoscopie lorsqu'un seul examen peut être réalisé. Les caractéristiques tomodensitométriques et endoscopiques de 17 chiens et 5 chats avec un diagnostic de tumeur nasale confirmé histologiquement ou cytologiquement ont été analysées rétrospectivement. Le degré de suspicion de tumeur nasale permis par l'endoscopie et/ou le scanner a été comparé au diagnostic final. Un examen tomodensitométrique a été réalisé chez 12 animaux, une rhinoscopie chez 14 et les deux examens ont été couplés dans quatre cas. L'examen scanner a conclu qu'une tumeur nasale était le diagnostic le plus probable dans 11 cas sur 12 (92 %), et la rhinoscopie dans 9 cas sur 14 (64 %). L'examen scanner apparait plus fiable que la rhinoscopie pour détecter les tumeurs nasales, et de ce fait devrait être considéré comme le meilleur examen de première intention.(Traduit par les auteurs).

Supplementing honey bee (Hymenoptera: Apidae) colonies with pollen increases their pollinating activity on nectariferous crops with anthers isolated from stigmas.

The western honey bee (Apis mellifera L.) is the most globally used managed pollinator species, but it can have limited pollinating activity on nectariferous crops displaying anthers isolated from stigmas, i.e., when anthers are spatially or temporally separated from stigma within or between flowers. We supplemented honey bee colonies with pollen in the combs or in paste form laid on top of the hive frames to test if these treatments could reduce their pollen foraging and increase their pollinating activity in a monoecious and nectariferous cultivar of cantaloupe melon (Cucumis melo L.), in comparison with control colonies not supplemented. We recorded the pollen forager density per flower, the number of pollen grains deposited per stigma and their resulting fruit set, seed set and fruit mass, before and after the colony pollen supplementations. The number of pollen grains deposited by honey bees on stigmas increased gradually after pollen supplementation in the combs. But pollen foraging decreased only moderately, and no effect could be observed on any yield component except the seed set. On the other hand, there was no effect of the pollen paste laid on top of the frames either on stigmatic pollen loads, on colony pollen foraging or on any yield component. Supplementing honey bee colonies with pollen in the combs can therefore be an effective means for increasing their pollinating activity in nectariferous crops displaying anthers isolated from stigmas, e.g., Amaryllidaceae, Apiaceae, Cucurbitaceae, avocado, all hybrid seed productions. The context for the potential use of pollen substitutes is discussed.

A large-scale dataset reveals taxonomic and functional specificities of wild bee communities in urban habitats of Western Europe.

Wild bees are declining, mainly due to the expansion of urban habitats that have led to land-use changes. Effects of urbanization on wild bee communities are still unclear, as shown by contrasting reports on their species and functional diversities in urban habitats. To address this current controversy, we built a large dataset, merging 16 surveys carried out in 3 countries of Western Europe during the past decades, and tested whether urbanization influences local wild bee taxonomic and functional community composition. These surveys encompassed a range of urbanization levels, that were quantified using two complementary metrics: the proportion of impervious surfaces and the human population density. Urban expansion, when measured as a proportion of impervious surfaces, but not as human population density, was significantly and negatively correlated with wild bee community species richness. Taxonomic dissimilarity of the bee community was independent of both urbanization metrics. However, occurrence rates of functional traits revealed significant differences between lightly and highly urbanized communities, for both urbanization metrics. With higher human population density, probabilities of occurrence of above-ground nesters, generalist and small species increased. With higher soil sealing, probabilities of occurrence of above-ground nesters, generalists and social bees increased as well. Overall, these results, based on a large European dataset, suggest that urbanization can have negative impacts on wild bee diversity. They further identify some traits favored in urban environments, showing that several wild bee species can thrive in cities.

Possible Spillover of Pathogens between Bee Communities Foraging on the Same Floral Resource.

Viruses are known to contribute to bee population decline. Possible spillover is suspected from the co-occurrence of viruses in wild bees and honey bees. In order to study the risk of virus transmission between wild and managed bee species sharing the same floral resource, we tried to maximize the possible cross-infections using Phacelia tanacetifolia, which is highly attractive to honey bees and a broad range of wild bee species. Virus prevalence was compared over two years in Southern France. A total of 1137 wild bees from 29 wild bee species (based on COI barcoding) and 920 honey bees (Apis mellifera) were checked for the seven most common honey bee RNA viruses. Halictid bees were the most abundant. Co-infections were frequent, and Sacbrood virus (SBV), Black queen cell virus (BQCV), Acute bee paralysis virus (ABPV) and Israeli acute paralysis virus (IAPV) were widespread in the hymenopteran pollinator community. Conversely, Deformed wing virus (DWV) was detected at low levels in wild bees, whereas it was highly prevalent in honey bees (78.3% of the samples). Both wild bee and honey bee virus isolates were sequenced to look for possible host-specificity or geographical structuring. ABPV phylogeny suggested a specific cluster for Eucera bees, while isolates of DWV from bumble bees (Bombus spp.) clustered together with honey bee isolates, suggesting a possible spillover.

Mutations in potato virus Y genome-linked protein determine virulence toward recessive resistances in Capsicum annuum and Lycopersicon hirsutum.

The recessive resistance genes pot-1 and pvr2 in Lycopersicon hirsutum and Capsicum annuum, respectively, control Potato virus Y (PVY) accumulation in the inoculated leaves. Infectious cDNA molecules from two PVY isolates differing in their virulence toward these resistances were obtained using two different strategies. Chimeras constructed with these cDNA clones showed that a single nucleotide change corresponding to an amino acid substitution (Arg119His) in the central part of the viral protein genome-linked (VPg) was involved in virulence toward the pot-1 resistance. On the other hand, 15 nucleotide changes corresponding to five putative amino acid differences in the same region of the VPg affected virulence toward the pvr2(1) and pvr2(2) resistances. Substitution models identified six and five codons within the central and C terminal parts of the VPg for PVY and for the related potyvirus Potato virus A, respectively, which undergo positive selection. This suggests that the role of the VPg-encoding region is determined by the protein and not by the viral RNA apart from its protein-encoding capacity.

A novel strategy for creating recombinant infectious RNA virus genomes.

Reverse transcriptases with RNase H activity are particularly apt to switch templates and generate recombinant molecules in vitro. This property has been exploited for the first time to create a library of recombinant RNAs 3 between two strains of Cucumber mosaic virus (CMV) or between CMV and Tomato aspermy virus (TAV), which share 75 and 63% sequence identity, respectively. The recombination events were almost entirely of the precise homologous type, and occurred at the same sites as those previously identified in co-infected plants, making it possible to use this strategy to create numerous cDNA fragments with crossovers similar to those occurring in vivo. Sub-cloning of recombinant fragments into an infectious full-length clone was accomplished by homologous recombination in yeast, alleviating the need for in vitro ligation at common restriction sites. Most of the recombinant genomes were infectious. Association of these two methods constitutes an efficient and practical means for generating numerous infectious viral genomes equivalent to ones that might arise by precise homologous recombination between two parental viral genomes in nature.

Decreasing abundance, increasing diversity and changing structure of the wild bee community (Hymenoptera: Anthophila) along an urbanization gradient.

BACKGROUND: Wild bees are important pollinators that have declined in diversity and abundance during the last decades. Habitat destruction and fragmentation associated with urbanization are reported as part of the main causes of this decline. Urbanization involves dramatic changes of the landscape, increasing the proportion of impervious surface while decreasing that of green areas. Few studies have investigated the effects of urbanization on bee communities. We assessed changes in the abundance, species richness, and composition of wild bee community along an urbanization gradient. METHODOLOGY/PRINCIPAL FINDINGS: Over two years and on a monthly basis, bees were sampled with colored pan traps and insect nets at 24 sites located along an urbanization gradient. Landscape structure within three different radii was measured at each study site. We captured 291 wild bee species. The abundance of wild bees was negatively correlated with the proportion of impervious surface, while species richness reached a maximum at an intermediate (50%) proportion of impervious surface. The structure of the community changed along the urbanization gradient with more parasitic species in sites with an intermediate proportion of impervious surface. There were also greater numbers of cavity-nesting species and long-tongued species in sites with intermediate or higher proportion of impervious surface. However, urbanization had no effect on the occurrence of species depending on their social behavior or body size. CONCLUSIONS/SIGNIFICANCE: We found nearly a third of the wild bee fauna known from France in our study sites. Indeed, urban areas supported a diverse bee community, but sites with an intermediate level of urbanization were the most speciose ones, including greater proportion of parasitic species. The presence of a diverse array of bee species even in the most urbanized area makes these pollinators worthy of being a flagship group to raise the awareness of urban citizens about biodiversity.

Biological properties and relative fitness of inter-subgroup cucumber mosaic virus RNA 3 recombinants produced in vitro.

In vitro reverse transcription of a mixture of total RNA from plants infected with the I17F or R strains of cucumber mosaic virus (CMV), representative of subgroups IA and II, respectively, results in viral cDNA populations including rare recombinant RNA 3 molecules, some of which also have point mutations. The biological properties of 17 recombinants in the capsid gene or the 3' non-coding region of RNA 3 were evaluated when associated with I17F RNAs 1 and 2. Six viruses displayed deficiencies (non-viability, deficiencies for movement and/or replication, delayed infection, loss of aphid transmissibility). Nine induced symptoms close to those of I17F-CMV on tobacco and pepper plants. All recombinants bearing the movement protein (MP) of R-CMV and part or most of the capsid protein (CP) of I17F-CMV, as well as the recombinant created in vitro by exchanging the corresponding open reading frames, also induced filiformism on tobacco, but induced only faint symptoms on melon. Two recombinants induced atypically severe symptoms on both tobacco and pepper. Most of the recombinants generally accumulated to lower levels than the wild-type I17F strain in tobacco. Three recombinants, however, including one responsible for severe symptoms, accumulated to generally higher levels than I17F-CMV. When two of these were tested in co-infection experiments with I17F RNA 3, they proved to be poorly competitive, suggesting that they would be unlikely to emerge in the field.