No abstract

Nosemosis is a disease of adult honey bees, Apis mellifera Linnaeus (Hymenoptera: Apidae), caused by two described species of Microsporidia: Nosema ceranae Fries and Nosema apis Zander. The epidemiology of N. apis is well understood; however, little is known about N. ceranae in Canadian apiaries. The following study aimed to determine the seasonal patterns of N. ceranae and N. apis in European honey bees in a Québec, Canada, apiary. Honey bees from six hives were sampled from 2008 to 2010 and the amount of spores quantified by both microscopic spore counts and duplex quantitative polymerase chain reaction (qPCR). Results demonstrated that duplex qPCR was the most sensitive technique and was able to detect N. ceranae in samples confirmed negative for microscopic spore counts and conventional polymerase chain reaction (PCR) detection. Results show that N. ceranae is the more prevalent parasite and was present in 75% of collections as single or mixed infections in the sampled apiary. The prevalence of N. apis was lower representing 29.7% throughout the 3 years of the study, and by 2010 was present only as mixed infections. Seasonal patterns of N. apis were consistent with previously published data with peaks in spring and autumn months, while N. ceranae peak infections varied throughout the 3-year study. Résumé-Lanosémose est une maladie des abeilles domestiques, Apis mellifera Linnaeus (Hymenoptera: Apidae) causée par deux espèces de Microsporidia: Nosema ceranae Fries et Nosema apis Zander. L 0 épidémiologie de N. apis est bien étudiée, mais très peu est connu de l 0 épidémiologie de N. ceranae au Canada. Cette étude vise à déterminer les tendances saisonnières de N. ceranae et N. apis dans les abeilles d'un rucher au Québec, Canada. Des abeilles de six ruches ont été échantillonnées entre 2008 et 2010 et la quantité de spores a été quantifiée par des méthodes microscopiques et duplex de qPCR. Les résultats ont démontré que le duplex de qPCR était plus sensible que les méthodes microscopiques et était capable de détecter N. ceranae dans des échantillons qui ont été confirmés négatifs par les méthodes microscopiques. Les résultats ont aussi démontré que N. ceranae est plus répandu que N. apis et est présent dans 75% des échantillons dans le rucher examiné. Nosema apis est moins répandu avec seulement 29.7% des échantillons et était présent en 2010 seulement en tant que co-infections. Les tendances saisonnières de N. apis sont cohérentes avec des données déjà publiées avec des pics au printemps et en automne, cependant les pics de N. ceranae ont été variés pendant la durée de l 0 étude.

Field resistances (FR) against rice blast are highly evaluated by breeders for their durability, in contrast to the conspicuous but often less durable true resistances. However, lack of efficient systems for evaluation of resistance has delayed their practical application. Kahei, an upland domestic cv., is known for its very high FR against rice blast. We fine-mapped its highest quantitative trait loci (QTL), qBFR4-1, using residual heterozygosity of recombinant inbred lines (RILs) and our semi-natural rice blast inoculation/evaluation system in the greenhouse, with comparable accuracy to the true resistance genes. This system enabled reproducible high-density infection, and consequently allowed quantification of the resistance level in individual plants. The target region was first narrowed down to about 1 Mb around at 32 Mb from the top of chromosome 4 in the Nipponbare genome, with the upland evaluation system assessing the F7 generation of Koshihikari (lowland, FR: very weak) x Kahei (upland, FR: very strong) RILs. Then, F9 plants (4,404)--siblings of hetero F8 plants at the region--were inoculated with rice blast in a greenhouse using the novel inoculation system, and individual resistance levels were diagnosed for fine QTL analysis and graphical genotyping. Thus, the resistance gene was fine-mapped within 300 kb at 31.2-31.5 Mb on chromosome 4, and designated Pikahei-1(t). By annotation analysis, seven resistance gene analog (RGA) ORFs of nucleotide-binding-site and leucine-rich-repeat (NBS-LRR)-type were found in the center of the region as the most likely candidate counterparts of the resistance gene. This is similar in structure to the recently reported Pik cluster region, suggesting that most of the other dominant QTLs of the FRs may have similar RGA structures.

Microencapsulation of living cells may serve as an alternative therapy for patients requiring organ transplants. One of the limiting factors in the progress of such therapy is attaining a biocompatible and mechanically stable polymer. The current study investigates the potential of a novel membrane combining alginate, chitosan, polyethylene glycol (PEG) and poly-L-lysine (PLL) with the objective of proposing a membrane suitable for cell entrapment that may overcome some of the shortcomings of the widely studied alginate-poly-L-lysine-alginate (APA) capsules. The novel microcapsule was formulated using a 1.5% alginate solution coated with 0.05% chitosan, 0.1% PEG and 0.05% poly-L-lysine with a final layer of 0.1% alginate. Microcapsules having a diameter of 450 ± 30 μm were prepared. Upon citrate treatment, the membrane remained intact and retained its spherical structure. The membrane was able to support liver cell proliferation and the encapsulated cells were capable of secreting proteins. The study demonstrated that the new membrane can be used for cell entrapment. However, further investigations are needed to assess its potential for long term transplantation and usage in the development of bioartificial organs.