Production of seed potatoes in Cyprus: incidence and economic importance of virus diseases

Summary Since 1981 seed potatoes have been produced on a semi-commercial scale in Cyprus by single multiplication of imported class A stocks. The main virus in these locally produced seed potatoes was potato leaf roll virus (PLRV) which was detected in 369 of 658 seed crops examined, at an average incidence of ca 1.5% (range 0.1%–15%). Tuber infections were detected in 203 of 223 samples tested, at an average incidence of ca 6.8% (range 1–32%), indicating a considerable spread of the virus during local seed multiplication. Potato viruses Y, X and A, and alfalfa mosaic virus occurred at much lower incidence than PLRV. The effect of secondary PLRV infection on ware-potato yield was determined in the cultivars Spunta and Cara, each planted on two different dates. In all four cultivar-planting date combinations there was a very close negative correlation between yield and virus incidence. At 100% infection, losses in total yield varied from 46% (later planting of Cara) to 72% (earlier planting of Spunta). The threshold level of infection for significant losses was ca 10%.     

Predatory fish select for coordinated collective motion in virtual prey

Movement in animal groups is highly varied and ranges from seemingly disordered motion in swarms to coordinated aligned motion in flocks and schools. These social interactions are often thought to reduce risk from predators, despite a lack of direct evidence. We investigated risk-related selection for collective motion by allowing real predators (bluegill sunfish) to hunt mobile virtual prey. By fusing simulated and real animal behavior, we isolated predator effects while controlling for confounding factors. Prey with a tendency to be attracted toward, and to align direction of travel with, near neighbors tended to form mobile coordinated groups and were rarely attacked. These results demonstrate that collective motion could evolve as a response to predation, without prey being able to detect and respond to predators.     

Biological activity of immunostimulatory CpG DNA motifs in domestic animals

Bacterial DNA contains a much higher frequency of CpG dinucleotides than are present in mammalian DNA. Furthermore, bacterial CpG dinucleotides are often not methylated. It is thought that these two features in combination with specific flanking bases constitute a CpG motif that is recognized as a "danger" signal by the innate immune system of mammals and therefore an immune response is induced when these motifs are encountered. These immunostimulatory activities of bacterial CpG DNA can also be achieved with synthetic CpG oligodeoxynucleotides (ODN). Recognition of CpG motifs by the innate immune system requires engagement of Toll-like receptor 9 (TLR-9), which induces cell signaling and subsequently triggers a pro-inflammatory cytokine response and a predominantly Th1-type immune response. CpG ODN-induced innate and adaptive immune responses can result in protection in various mouse models of disease. Based on these observations, clinical trials are currently underway in humans to evaluate CpG ODN therapies for cancer, allergy and infectious disease. However, potential applications for immunostimulatory CpG ODN in species of veterinary importance are just being explored. In this review, we will highlight what is presently known about the immunostimulatory effects of CpG ODN in domestic animals.     

Efficacy of an intranasal modified live bovine respiratory syncytial virus and temperature-sensitive parainfluenza type 3 virus vaccine in 3-week-old calves experimentally challenged with PI3V

Two experimental parainfluenza type 3 virus (PI3V) challenge studies were undertaken to evaluate the efficacy of a single intranasal dose of an attenuated live vaccine containing modified live bovine respiratory syncytial virus (BRSV) and temperature-sensitive PI3V in 3-week-old calves. In the first study, vaccine efficacy was evaluated in colostrum deprived calves. Nasal shedding of PI3V was highly significantly reduced in vaccinated calves challenged 10 days or 21 days after vaccination. In the second study, vaccine efficacy was assessed in calves with maternal antibodies against PI3V by challenge 66 days post-vaccination. Vaccination also significantly reduced PI3V excretion after challenge in this study. In both studies, clinical signs after challenge were very mild and were not different between vaccinated and control calves.     

Soil solarization as a substitute for methyl bromide fumigation in greenhouse tomato production in Cyprus

Preplant soil fumigation with methyl bromide (MB) is presently standard practice in greenhouse tomato production. Since this compound is scheduled to be phased out by 2005, the possibility of using solarization as an alternative soil disinfestation method was examined in four greenhouse tomato trials. Solarization was applied for 8 weeks in July-August, using transparent polyethylene sheets for soil mulching, and compared with MB fumigation applied in September, before planting, at 80 g/m². Solarization raised the maximum soil temperature by 9°C and reduced the population density ofFusarium spp. in soil by 91–98%. Similar reductions of soil inoculum (95–99%) were obtained with MB fumigation. Both methods provided effective control of Fusarium wilt, Verticillium wilt and corky root rot on tomato plants. MB fumigation was in addition highly effective against root-knot nematodes, whereas nematode control with solarization did not exceed 50%. Both treatments resulted in similar fruit yield increases, ranging within 90–140% compared with plants grown in untreated soil. During the second cropping season following soil treatment, solarization exhibited two times higher residual effectiveness against vascular wilt diseases compared with MB fumigation. The latter treatment, however, was superior to solarization in its residual effectiveness against root-knot nematodes and to a lesser extent against corky root rot. Fruit yields from solarized and MB-fumigated soil during the second cropping season were higher than those obtained from untreated soil by approximately 35% and 60%, respectively. In Cyprus, solarization appears to be an effective alternative to MB fumigation in greenhouse tomato production, especially if integrated with other approaches enabling more effective nematode control.     

Integrating soil solarization with grafting on resistant rootstocks for management of soil-borne pathogens of eggplant

Summary

Soil solarization and grafting onto a resistant tomato rootstock (‘Brigeor F1‘), and the integrated use of both methods were evaluated in four field trials carried out in Cyprus, for management of soil-borne pathogens and pests of eggplant. Soil solarization was highly effective against Verticillium wilt (V. dahliae) but only partially effective against corky root rot (Pyrenochaeta lycopersici) and root-knot nematodes (Meloidogyne spp.); it also controlled adequately most annual weeds. By contrast, grafting provided complete protection from corky root rot and root-knot, but only partial protection from Verticillium wilt. Complete resistance to nematodes, however, occurred only in trials with greenhouse-grown (winter) crops. In open-field (summer) crops, about 50% of the grafted plants sustained slight nematode infection, apparently because of breakdown of resistance at high soil temperatures. Solarization, or grafting gave significant yield increases over that of the untreated check. However, a combination of both was much more effective than either alone. Together, they provided complete protection from all three diseases. Most importantly, they had an additive effect on yield, resulting in a significant increase over that obtained by either method alone. The average yield (kg plant-1) obtained in two greenhouse trials was 9002E5 for the control, 16.1 for grafting alone, 14.1 for solarization alone and 20.2 for the combination of the two methods. The integrated use of solarization and grafting appears to be a sustainable alternative to methyl bromide fumigation.     

Dipstick test for DNA-based food authentication. Application to coffee authenticity assessment

This paper reports DNA-based food authenticity assays, in which species identification is accomplished by the naked eye without the need of specialized instruments. Strongly colored nanoparticles (gold nanoparticles) are employed as reporters that enable visual detection. Furthermore, detection is performed in a low-cost, disposable, dipstick-type device that incorporates the required reagents in dry form, thereby avoiding multiple pipetting and incubation steps. Due to its simplicity, the method does not require highly qualified personnel. The procedure comprises the following steps: (i) PCR amplification of the DNA segment that flanks the unique SNP (species marker); (ii) a 15 min extension reaction in which DNA polymerase extends an allele-specific primer only if it is perfectly complementary with the target sequence; (iii) detection of the products of the extension reaction within a few minutes by the naked eye employing the dipstick. No purification is required prior to application of the extension products to the dipstick. The method is general and requires only a unique DNA sequence for species discrimination. The only instrument needed is a conventional thermocycler for PCR, which is common equipment in every DNA laboratory. As a model, the method was applied to the discrimination of Coffea robusta and arabica species in coffee authenticity assessment. As low as 5% of Robusta coffee can be detected in the presence of Arabica coffee.     

Use of Modified Zeolites for the Remediation of Waters and Cultivated Soils from Cu(II)

The ability of iron oxides (goethite) and natural zeolite (clinoptilolite) to adsorb copper from its aqueous solutions was extensively studied in the past. In this paper, the production of modified zeolites (systems I and II) from raw materials of zeolite and goethite was investigated compared to the initial materials. These two systems presented higher adsorption than goethite or clinoptilolite. Comparing the two systems, system II presented higher adsorption than system I. Isotherm studies showed that the adsorption data from all materials were best described by Freundlich isotherm. According to thermodynamic study, the values of ??G° became more negative with the increase of temperature, indicating that the adsorption process was more favorable to higher temperature. The positive values of ??H° indicated endothermic nature of adsorption. The use of all adsorptive materials as soil improvements was also investigated. Goethite, zeolite, and systems I and II were mixed separately with three different soils (clay loam, sandy loam, and loamy sand). Lettuces were cultivated, and the combination of system II with the loamy sand soil led to the best morphological characteristics of lettuces with the minimum adsorption of copper. Consequently, modified zeolites could be considered as two satisfactory detergents of highly copper concentration in soil and water.