Advances and prospects for management of TB transmission between badgers and cattle

Bovine tuberculosis (bTB) is the most serious endemic disease facing the livestock industry in the United Kingdom (UK) and Republic of Ireland (RoI), where its management has been confounded by the presence of persistent infection in the Eurasian badger (Meles meles). Field evidence suggests that the social structure of badger populations can have an important influence on disease dynamics, and on the outcome of management interventions. Recent, large-scale badger culling experiments in the UK and RoI had complex epidemiological outcomes. In the UK, proactive culling led to reduced bTB incidence in cattle herds inside culled areas, but a temporary increase in adjacent areas. Reactive culling in response to herd breakdowns was associated with an increase in the incidence of bTB in cattle. In contrast, badger culling in RoI was reported to have only beneficial effects on bTB incidence in cattle. The reasons for these differences are not clear. The complexity of the evidence base for culling is highlighted by the different management approaches currently being adopted by the different authorities of the UK and RoI. It is generally accepted that a holistic approach to bTB management, which targets both cattle and wildlife, is necessary. Consequently recent research activities have also focussed on cattle and badger vaccines, and biosecurity on farms. This paper describes recent advances in our understanding of the epidemiology of bTB in badgers and the consequences of culling, and current research to develop approaches for the vaccination of badgers, and methods of managing the risks of contact between badgers and cattle in farm buildings.     

Production of the seed germination stimulant karrikinolide from combustion of simple carbohydrates

The naturally occurring seed germination stimulant karrikinolide is formed from the combustion of plant material including cellulose. It has previously been reported that combustion of simple carbohydrates such as d-glucose does not produce extracts containing karrikinolide. Moreover, it was reported that extracts with germination-promoting ability could be obtained only by combustion of simple carbohydrates in the presence of amino acids such as l-glycine. By employing a (13)C-labeled karrikinolide to physically quantify natural karrikinolide, we now show that it is produced from combustion of simple carbohydrates in similar amounts regardless of whether l-glycine is present or not. The addition of l-glycine appears to be beneficial in reducing the inhibitory effect of smoke extracts and provides a greater concentration range for effective germination-promoting activity.     

Spatial Distribution of Bulk Atmospheric Deposition of Heavy Metals in Metropolitan Sydney, Australia

The detailed spatial distribution of atmospheric deposition flux of pollutants in metropolitan Sydney, Australia (ca. 480 km²) is investigated through the direct simultaneous sampling of bulk deposition adjacent to roads with various traffic volumes and at background sites over a period of 1 year. Based on the field results and detailed land-use analyses, atmospheric deposition rates of copper, lead and zinc are calculated for the metropolitan region, and the contributions to stormwater pollutant loads are evaluated. Total particulates and heavy metals in bulk atmospheric deposition are found to be temporally consistent, and to exhibit strong correlations with road proximity and traffic volume. The material captured adjacent to major roads has a distinct average composition of 862 mg/kg copper, 364 mg/kg lead and 4,617 mg/kg zinc. Modelling accounting for road proximity, traffic volume and land-use affords annualised stormwater-entrainable depositional fluxes of 6.5, 4.1, 47.2 and 10,800 kg/km²/year for copper, lead and zinc.     

Phoma black stem severity and phytoestrogen production in annual Medicago spp. is primarily determined by interaction of cultivar and pathogen isolate

Phoma black stem and leaf spot disease (caused by Phoma medicaginis) not only diminishes forage and seed yield but stimulates production of detrimental phytoestrogens in annual Medicago spp. This study aimed to evaluate relationships between disease development from five isolates of P. medicaginis on 16 cultivars with production of coumestrol and 4′-O-methylcoumestrol. In the presence of P. medicaginis, Sava had the highest coumestrol and 4′-O-methylcoumestrol (640 and 85 mg/kg, respectively) followed by Caliph (253 and 15 mg/kg, respectively). In the absence of P. medicaginis, Jemalong and Paragosa showed highest and lowest coumestrol (137 and 0 mg/kg, respectively). 4′-O-methylcoumestrol was not produced in disease-free plants, but coumestrol was. Disease incidence and severity on leaves and on petiole/stems, and consequent leaf yellowing severity ranged from 5%–98.7%, 0%–100%, 4.4%–98.7%, 1.7%–100%, and 0%–85%. Sava, Paraponto, Harbinger, and Serena were most susceptible, while Tornafield and Caliph were least susceptible. There was significant overall positive correlation of disease incidence/severity factors across cultivars (p < 0.01) with both coumestrol and 4′-O-methylcoumestrol. Jemalong was least responsive and Paragosa and Sava most responsive to coumestrol production following P. medicaginis inoculation. Coumestrol in inoculated Paragosa increased to 373 mg/kg in comparison with 0 mg/kg in controls. These findings are of critical importance towards developing less disease-susceptible annual Medicago spp. producing less detrimental phytoestrogens. Least susceptible cultivars like Tornafield and Caliph can be used to manage yield loss, whilst least responsive cultivars to phytoestrogen production like Caliph also can help to reduce phytoestrogen production.     

Identification of QTLs associated with resistance to Phomopsis pod blight (Diaporthe toxica) in Lupinus albus

Phomopsis blight in Lupinus albus is caused by a fungal pathogen, Diaporthe toxica. It can invade all plant parts, leading to plant material becoming toxic to grazing animals, and potentially resulting in lupinosis. Identifying sources of resistance and breeding for resistance remains the best strategy for controlling Phomopsis and reducing lupinosis risks. However, loci associated with resistance to Phomopsis blight have not yet been identified. In this study, quantitative trait locus (QTL) analysis identified genomic regions associated with resistance to Phomopsis pod blight (PPB) using a linkage map of L. albus constructed previously from an F₈ recombinant inbred line population derived from a cross between Kiev-Mutant (susceptible to PPB) and {"type":"entrez-protein","attrs":{"text":"P27174","term_id":"14195583","term_text":"P27174"}}P27174 (resistant to PPB). Phenotyping was undertaken using a detached pod assay. In total, we identified eight QTLs for resistance to PPB on linkage group (LG) 3, LG6, LG10, LG12, LG17 and LG27 from different phenotyping environments. However, at least one QTL, QTL-5 on LG10 was consistently detected in both phenotyping environments and accounted for up to 28.2% of the total phenotypic variance. The results of this study showed that the QTL-2 on LG3 interacts epistatically with QTL-5 and QTL-6, which map on LG10 and LG12, respectively.     

Adjuvant-enhanced antibody responses in the absence of toll-like receptor signaling

Innate immune signals mediated by Toll-like receptors (TLRs) have been thought to contribute considerably to the antibody-enhancing effects of vaccine adjuvants. However, we report here that mice deficient in the critical signaling components for TLR mount robust antibody responses to T cell-dependent antigen given in four typical adjuvants: alum, Freund's complete adjuvant, Freund's incomplete adjuvant, and monophosphoryl-lipid A/trehalose dicorynomycolate adjuvant. We conclude that TLR signaling does not account for the action of classical adjuvants and does not fully explain the action of a strong adjuvant containing a TLR ligand. This may have important implications in the use and development of vaccine adjuvants.     

Grapevine (Vitis spp.) dynamics in association with manual tending,physiography, and host tree associations in temperate deciduous forests

The role of lianas (woody vines) in the development and diversity of both tropical and temperate forests under differing management scenarios has not been thoroughly explored. We examined changes in grapevine (Vitis spp.) densities over time in clearcut stands as influenced by manual tending, physiography, and host tree associations. We used data from long-term studies on 66 clearcut stands dominated by temperate deciduous forest tree species on the Hoosier National Forest in south-central Indiana, USA. Fourteen of the stands had grapevines removed manually, approximately during the stem exclusion stage of development. Grapevine densities steadily increased from age 5 until age 15, which coincides with the period of stem exclusion of these stands. Subsequent grapevine mortality may have been related to light competition. Manually treated stands had similar grapevine densities as untreated stands after 20 years across sites, and it appeared that only on the most xeric area was the grapevine treatment effective in reducing grapevine densities. During early stand development, ranging from ages 5 to 17, grapevine density was strongly related to slope position, but as stands developed through the stem exclusion stage, aspect emerged as a stronger factor influencing grapevine density. Black cherry (Prunus serotina Ehrh.), walnut (Juglans spp.), and elm (Ulmus spp.) were the most common grapevine host trees under both treated and untreated scenarios, which may be associated with the crown architecture of these species. Results suggest lianas play a critical role in the early development of disturbed forest sites in temperate deciduous forests. With concerns that lianas are increasing in abundance and distribution in these forest types, understanding their role in forest dynamics, such as host tree associations at different stages of development, competition dynamics on different sites and corresponding influences on tree growth, species composition, and diversity, will be critical to decision-making processes in achieving desired management goals in the future.     

Genetics of stem rust resistance in the spring wheat cultivar Thatcher and the enhancement of stem rust resistance by <Emphasis Type="Italic">Lr34</Emphasis>

Three recombinant inbred line populations from the crosses RL6071/Thatcher, RL6071/RL6058 (Thatcher Lr34), and Thatcher/RL6058, were used to study the genetics of stem rust resistance in Thatcher and TcLr34. Segregation of stem rust response in each population was used to determine the number of genes conferring resistance, as well as the effect of the leaf rust resistance gene Lr34 on stem rust resistance. The relationship between resistance in seedling and adult plants was also examined, and an attempt was made to identify microsatellite markers linked to genes that were effective in adult plants. In field plot tests at least three additive resistance genes segregated in the RL6071/RL6058 population, whereas two resistance genes segregated in the RL6071/Thatcher population. The presence of the gene Lr34 permitted the expression of additional stem rust resistance in Thatcher-derived lines both at the seedling and adult plant stages. Seedling resistance to races TPMK and RKQQ was significantly associated with resistance in adult plants, whereas seedling resistance to races QCCD and QCCB may have made a minor contribution. The seedling resistance genes Sr16 and Sr12 may have contributed to resistance in adult plants. A molecular marker linked to resistance in adult plants was identified on chromosome 2BL.     

Phytochemical diversity in tubers of potato cultivars and landraces using a GC-MS metabolomics approach

Phytochemical diversity with respect to a range of polar (including amino acids, organic acids, sugars, and sugar alcohols) and nonpolar (including fatty acids, alkanols, and sterols) metabolites was examined within tubers from a total of 29 genetically diverse potato cultivars and Chilean landraces using a metabolomics approach by gas chromatography-mass spectrometry. From principal component analysis of the polar and nonpolar metabolite data there was insufficient variation to differentiate the majority of cultivars and landraces. Analysis of all polar metabolite profiles revealed separation of two cultivars (Glenna and Morag) from the other cultivars and landraces and a separate cluster of one landrace line, largely due to higher levels of sugars. Pentland Javelin was distinct in containing high levels of many amino acids. The two Solanum tuberosum group phureja cultivars (Inca Sun and Mayan Gold) were not particularly similar and were not separated from the S. tuberosum group tuberosum cultivars. Analysis of the nonpolar metabolite data revealed partial separation of two landrace lines and, on the basis of some minor fatty acids, Mayan Gold was distinct. The differences in metabolite profiles are considered in terms of the taxonomy and breeding history of the cultivars and possible influences from other factors such as developmental stage of the tuber. With a view to exploring biosynthetic links between metabolites, a pairwise correlation analysis was performed on all metabolites. The significance of high correlations between many amino acids and between several nonpolar metabolites is discussed.     

The effect of transportation on the juvenile scallop Pecten maximus (L.)

At the present time, there is little information concerning the effect of transport on the physiology of scallops. Therefore, the overall objective of this study was to use the adenylic energetic charge (AEC) as an indicator of stress in scallops. Three transport trials were carried out: dry transport in polystyrene boxes containing seaweed and transport by vivier lorry at various densities. Post-transport scallop mortality was low for all trials, but the AEC results showed that scallop stress was reduced when animals were transported by vivier truck compared with dry transport. AEC levels in scallops remained high after 24.75 h of vivier transport in trial 2 (0.54–0.69) and after 17 h of vivier transport in trial 3 (0.79–0.82), whereas after 12 h of dry transport in trial 1, AEC levels in the striated muscle had decreased to 0.42. Ammonia concentration increased throughout the trials but did not appear to affect scallop survival in the short term. In general, the results indicate that greater survival can be achieved over longer distances (greater than 17 h) and at higher densities by vivier truck. However, better stability of holding units within tanks and a method to regulate ammonia and pH levels are needed if greater densities are used.