RNA‐transfected CD40‐activated B cells as a vaccine strategy in canine malignancies

Introduction: Cell‐based vaccine strategies using dendritic cells as cellular adjuvant have entered phase III trials in humans and have been found to be safe, feasible, and potentially efficacious. Canine patients are generally smaller than adult human patients, which makes production of canine dendritic cell (DC) vaccines problematic, given patient size and the small number of available DC precursors. Here we describe feasibility studies of a novel cell‐based vaccine strategy which uses CD40‐activated B‐cells (CD40‐B) loaded with RNA. This strategy is based on our observations that RNA‐transfected human CD40‐B can drive anti‐tumor T cell responses. One advantage of using CD40‐B cells is the ability to expand this cell population ex vivo, allowing for the numbers of cells required for therapeutic vaccines. Methods: Twenty milliliters of blood were drawn from 6 normal dogs and 5 canine lymphoma patients. Peripheral blood mononuclear cells were separated by Ficoll centrifugation. Culture conditions for B cell activation were optimized using CD40‐ligand, canine IL‐4, and Toll‐like receptor stimulus with CpGoligodinucleotides (ODN). Cyclosporine was added to eliminate peripheral T lymphocytes. Proliferation and activation of CD40‐B cells were demonstrated by CFSE dilution of B cells quantified by flow cytometry. Gene transfer was achieved by mRNA electroporation. Results: Marked in vitro stimulation and proliferation of canine peripheral B cells were achieved with soluble trimeric CD40L, canine IL‐4, and ODN. CD40‐B cells showed dramatic upregulation of MHC class II molecules and CD21 (B‐cell activation marker). After two weeks in culture, cells were negative for CD3 and CD4. Canine CD40‐B cells were efficiently transfected with mRNA, with >60% of CD40‐B expressing green fluorescent protein after GFP mRNA electroporation. Conclusion: RNA‐transfected CD40‐B cells can be efficiently generated from normal and tumor‐bearing dogs. These results provide rationale to test tumor RNA‐transfected CD40‐B as a novel therapeutic approach to treating canine malignancies. Clinical trials in canine lymphoma have been proposed.     

Modelling spatio-temporal dynamics of herbicide resistance

A mathematical model has been developed for the risk assessment of the spread of genes conferring herbicide resistance in plant populations. The model combines an age-and-stage-structured population dynamic model, a population genetic model and a model of spatial spread. This is achieved by embedding a local matrix population model into a cellular automaton model with raster cells as spatial units. The dynamics of each cell is determined by both its local dynamics and the interaction with neighbouring cells. The model is applied to the evaluation of management strategies to delay or even to prevent long-term evolution of resistance in an annual grass weed. The results show that the appearance and spread of resistant genes is a highly non-linear process exhibiting threshold phenomena, which occur for a wide range of parameters. The properties of the seed survival curve constitute the `genetic memory' of the system and thus determine its long-term dynamics. It is possible to delay the evolution of resistance by suspension of treatment, reduction in herbicide application rate and introducing fallow periods. Spatial spread from an infested plot is inhibited by leaving untreated strips between adjacent fields.     

Genetic and phenotypic diversity within the Fusarium graminearum species complex in Norway

European Journal of Plant Pathology - As has been observed in several European countries, the frequency of Fusarium head blight (FHB) caused by members of the Fusarium graminearum species complex...     

某规模化猪场暴发猪繁殖与呼吸综合征的诊治

猪繁殖与呼吸综合征病毒可以感染任何年龄的猪,主要引起怀孕母猪的流产、早产和死胎等繁殖障碍表现,仔猪和育肥猪感染病毒后可出现呼吸症状.业已证明猪繁殖与呼吸综合征病毒可以导致机体出现免疫抑制,因此感染该病毒后常会出现其他病原的继发感染,使疫情变得更为复杂和难以控制,使生产蒙受巨大的经济损失.对于猪繁殖与呼吸综合征的诊断方法主要包括血清学检测和病原检测两种.2005年上半年来,福建省某规模化猪场母猪出现高热、流产、死胎和产仔数下降等繁殖障碍,保育和生长育肥猪出现体表皮肤发绀、咳嗽、喷嚏、呼吸困难或腹式呼吸等临床表现.综合流行病学、临床表现和病理变化、血清学诊断和病原学诊断等结果分析表明,猪繁殖与呼吸综合征为该规模化猪场此次繁殖与呼吸障碍的主要原因.采用相应优质高效的弱毒疫苗全群进行紧急接种,同时加强卫生消毒及投喂抗生素避免继发感染等措施,目前疫情已经得到有效控制.     

Genetic Structure of Melampsora Epitea Populations in Swedish Salix Viminalis Plantations

Amplified fragment length polymorphism (AFLP) was used to study the genetic structure of populations of the willow leaf rust, Melampsora epitea, in Swedish willow plantations. In total, 197 isolates collected from Salix viminalis clones in three locations in Sweden were analysed. AFLP profiles based on 83 markers were used to compute genetic distances between pairs of individuals. High levels of gene and genotypic diversity were detected in all populations, with 96% of the AFLP loci being polymorphic and with normalized Shannon's diversity indices ranging from 0.977 to 1.0. Analysis of molecular variance (AMOVA) showed small significant differences among locations, although most of the molecular variability was found within locations (97.5%). Five isolates from one willow clone in one location differed markedly from the common pattern. When these five exceptional isolates were excluded, no significant differences among willow clones were found with AMOVA. Sexual reproduction and spore migration appear to be important factors for the population genetic structure of this pathogen.     

Molecular identification of blast resistance genes in rice landraces from northeastern India

Rice blast disease caused by the fungus Magnaporthe oryzae is one of the most devastating diseases causing huge losses worldwide. In the present study, major blast resistance genes were investigated in landraces originating from northeastern India. Based on phenotypic evaluation, 288 landraces were classified into three distinct groups: resistant (75), moderately resistant (127) and susceptible (86). The genetic frequencies of the 18 major blast resistance genes were between 6.2% and 27.4%, with only two genotypes possessing a maximum of nine blast resistance genes. The cluster and population structure analysis grouped the landraces into two groups. Through principal coordinate analysis, the scatter plots partitioned the resistant and moderately resistant landraces into different groups. Analysis of molecular variance showed maximum (96%) diversity within populations and least (4%) diversity between populations. Association analysis identified six markers, CRG4_2, RM72, tk59-2, pi21_79-3, RM1233 and RM6648, that are significantly associated with blast disease and explained a phenotypic variance of 1.1–6.5%. The associated genes could be used in marker-assisted rice breeding programmes for gene pyramiding to develop rice varietal resistance against blast disease. The present study represents a valuable blast resistance genetic resource that could be used for identification of new R genes, donors for blast resistance, and genomic studies.     

Influence of crop establishment methods on yield,economics and water productivity of rice cultivars under upland and lowland production ecologies of Eastern Indo-Gangetic Plains

A field study on assessment of crop establishment methods on yield, economics and water productivity of rice cultivars under upland and lowland production ecologies was conducted during wet seasons (June–November) of 2012 and 2013 in Eastern Indo-Gangetic Plains of India. The experiment was laid-out in a split-plot design (SPD) and replicated four times. The main-plot treatments included three crop establishment methods, viz. dry direct-seeded rice (DSR), system of rice intensification (SRI) and puddled transplanted rice (PTR). In sub-plots, five rice cultivars of different groups like aromatic (Improved Pusa Basmati 1 and Pusa Sugandh 5), inbreds (PNR 381 and Pusa 834) and hybrid (Arize 6444) were taken for their evaluations. These two sets of treatments were laid-out simultaneously in two production ecologies, upland and lowland during both years. In general, lowland ecology was found favourable for rice growth and yield and resulted in 13.2% higher grain yield as compared to upland ecology. Rice grown with SRI method produced 19.4 and 7.0% higher grain yield in 2012 and 20.6 and 7.1% higher in 2013, over DSR and PTR. However, PTR yielded 13.1 and 14.5% higher grain over DSR during 2012 and 2013, respectively. On an average, Arize 6444 produced 26.4, 26.9, 28.9 and 54.7% higher grain yield as compared to PS 5, P 834, PNR 381 and IPB1, respectively. Further, the interaction of production ecologies × crop establishment methods revealed that, in upland ecology, SRI recorded significantly higher grain yield as compared to PTR and DSR, but in lowland, grain yield resulting from SRI was similar to the yield obtained with PTR and significantly higher than DSR. The latter two methods (PTR and DSR) yielded alike in lowland ecology in both study years. The production ecologies × crop establishment methods × cultivars interaction on grain yield showed that the growing of Arize 6444 cultivar using SRI method in upland ecology resulted in the higher grain yield (8.87 t/ha). But the cost of production was also highest in SRI followed by PTR and DSR across production ecologies and cultivars. Cultivation of hybrid (Arize 6444) involved higher cost of production than all other cultivars. Irrespective of crop establishment methods and cultivars, gross returns, net returns and B:C ratio were significantly higher in lowland compared to upland ecology. Owing to higher grain yield, SRI method fetched significantly higher gross returns and net returns over PTR and DSR. Average increase in net return with Arize 6444 was 68.8, 41.0, 37.7 and 33.1% over IPB 1, PNR 381, P 834 and PS 5, respectively. There was a saving of 30.7% water in SRI and 19.9% in DSR over PTR under upland ecology. Similarly in lowland ecology, water saving of 30.2% was observed in SRI and 21.2% in DSR over PTR. Due to higher yield and saving on water, SRI returned significantly higher total water productivity (TWP) (5.9 kg/ha-mm) as compared to DSR (3.5 kg/ha-mm) and PTR (3.6 kg/ha-mm) under upland ecology. In lowland ecology, also SRI (6.2 kg/ha-mm) resulted in higher TWP as compared to other two methods. However, DSR gave significantly higher TWP as compared to PTR. Among cultivars, hybrid Arize 6444 recorded the highest TWP in both upland and lowland production ecologies across crop establishment methods. Hence, growing of hybrid Arize 6444 with SRI method can enhance rice productivity and water-use efficiency in lowland and upland production ecologies of Eastern Indo-Gangetic Plains and in other similar regions.     

Sri Lankan reservoir fishery: a case for introduction of a co-management strategy

The inland fisheries of Sri Lanka are essentially artisanal on most of the reservoirs in the country. The annual inland fish production declined dramatically after 1990, when state patronage for the development of the inland fisheries was discontinued for 4 years. This decline was shown to be a result of growth overfishing of the two dominant cichlid species which accounted for over 90% of landings. This was a result of using small mesh ( < 6.9 cm) gillnets in the absence of the State-sponsored monitoring procedure in the fishery after 1990. This indicates that it is necessary to monitor inland fisheries management in Sri Lanka through a centralized authority in the current situation. However, in some Sri Lankan reservoirs, fishing communities can be categorized as 'organized' because they collectively make decisions to define procedures for the rational exploitation of the fishery resources. In reservoirs with 'organized' fishing, the communities themselves have developed mechanisms to regulate the landing sizes of dominant cichlid fish species through community-based fisheries management strategies. In such reservoirs, over-exploitation of fish stocks was not evident, even after 1990, when state-sponsored monitoring procedures were suspended. Based on these observations, an alternative approach is recommended for the management of Sri Lankan reservoir capture fisheries in which the Government and resource-users have equal responsibilities in the management of the resources.