5S ribosomal gene clusters in wheat: pulsed field gel electrophoresis reveals a high degree of polymorphism

Summary The long-range structure of 5S rRNA gene clusters has been investigated in wheat (Triticum aestivum L.) by means of pulsed field gel electrophoresis. Using aneuploid stocks, 5S rRNA gene clusters were assigned to sites on chromosomes 1B, 1D, 513 and 5D. Cluster sizes were evaluated and the copy number of 5S DNA repeats was estimated at 4700-5200 copies for the short repeating unit (410 bp) and about 3100 copies for the long repeat (500 bp) per haploid genome. A comparison of wheat cultivars revealed extremely high levels of polymorphism in the 5S rRNA gene clusters. With one restriction enzyme digest all varieties tested gave unique banding patterns and, on a per fragment basis, 21-fold more polymorphism was detected among cultivars for 5S DNA compared to standard restriction fragment length polymorphisms (RFLPs) detected with single copy clones. Experiments with aneuploid stocks suggest that the 5S rRNA gene clusters at several chromosomal sites contribute to this polymorphism. A number of previous reports have shown that wheat cultivars are not easily distinguished by isozymes or RFLPs. The high level of variation detected in 5S rRNA gene clusters therefore offers the possibility of a sensitive fingerprinting method for wheat. 5S DNA and other macro-satellite sequences may also serve as hypervariable Mendelian markers for genetic and breeding experiments in wheat.     

MALE PEACH APHID ATTRACTION IN THE FIELD BY SEX PHEROMONES1)

Abstract Field trials by sex pheromone of aphid to trap peach aphids Myzus persicae have been carried out in 1995 and in 1996. Suitable time and the effect of ratio of two components nepetalactone and nepetalactol to apply the lure have been observed.     

Attachment styles impact on pet visitation effectiveness

Abstract

This paper describes a field study on the effects of attachment styles on the subjective well-being of institutionalized older persons after participating in a pet visitation program. We compared how attachment style (i.e., secure, anxious ambivalent, dismissive avoidant, and fearful avoidant) moderated the impact of a dog visitation program in 52 elderly residents of an assisted-living facility. Controlling for pre-visitation mood, the results revealed that the secure style related to increases in positive mood after interacting with the dogs. The anxious ambivalent style related to increases in positive mood and decreases in ratings of depression. Most importantly, the fearful avoidant style related to increases in depression after interacting with the dogs. The results highlight the notion that not all participants benefit from taking part in pet visitation programs. Theoretically, this study presents preliminary evidence for the relevance of attachment styles in understanding human–pet interactions.     

Field surveys on cooling effects of vegetation in an urban area

1. 1. Three kinds of field survey on different scales were carried out in Fukuoka City in summer to examine the relationship between the quantity of vegetation and air temperature.

2. 2. The field of the largerst scale measurement is across the city.

3. 3. Several parks and shrines of various sizes in the city were selected as other measurement areas.

4. 4. The most detailed measurements are carried out in a park with an area of 1.25 ha located in a down town area of the city.

5. 5. Though the amount of vegetation is expressed in a unique way in each survey, it is clearly found that the greener it is, the lower is the air temperature.

Simulated climate change: are passive greenhouses a valid microcosm for testing the biological effects of environmental perturbations?

This paper considers the use of passive greenhouse apparatus in field experiments investigating the biological consequences of climate change. The literature contains many accounts of such experiments claiming relevance of greenhouse treatment effects to global change scenarios. However, inadequacies in microclimate monitoring, together with incomplete understanding of greenhouse modes of action, cast doubt upon such claims. Here, treatment effects upon temperature (magnitude, range, variation, rates of change), moisture (humidity, precipitation, soil water content), light (intensity, spectral distribution), gas composition, snow cover, and wind speed are reviewed in the context of Intergovernmental Panel on Climate Change (IPCC) predictions. It is revealed that greenhouses modify each of these potentially limiting factors in a complex and interactive manner, but that the relationship between this modification and forecast conditions of climate change is poor. Interpretation of biological responses, and their extrapolation to predictive models, is thus unreliable. In order that future greenhouse experiments may overcome criticisms of artefact and lack of rigour, two amendments to methodology are proposed: (1) objective-orientated design of greenhouse apparatus (2) multiple controls addressing individual environmental factors. The importance of a priori testing of microclimate treatment effects is stressed.     

European beech in its northeasternmost stands in Europe: Varying climate-growth relationships among generations and diameter classes

Age, genetics and social status of trees affect their sensitivity to environmental factors, and information about such effects is needed for comprehensive assessment of growth potential. Climatic sensitivity of radial increment (i.e., tree-ring width) of introduced European beech (Fagus sylvatica L.) of different generations and social status, growing in its northeasternmost stands in Europe, was studied by dendroclimatological methods. At present, the studied stands occur outside of the natural distribution area of the species, providing opportunity to study adaptability and potential growth of beech in novel environments under changing climate. The sensitivity of radial growth to climatic factors was modulated by the generation and social status (size) of trees. The first generation trees, which were propagated from the material transferred from the northern Germany, were highly sensitive to climatic factors and showed wide spectrum of responses. The dominant trees were particularly sensitive to June precipitation, indicating sensitivity to water deficit in summer. The suppressed trees were mainly sensitive to temperature in the dormant period. Tree-ring width of the second generation trees, which were propagated from the first generation stands, was mainly affected by water deficit in summer, yet the local factors, modulated the mechanisms of response. In one stand, tree-ring width was affected by conditions during the formation of tree-ring, indicating direct influence of weather conditions on xylogenesis. In the other stand, tree-ring width was correlated to weather conditions in the preceding year, suggesting influence via carbohydrate reserves. The effect of social status on climatic sensitivity in the second generation stands was considerably weaker, likely due to the natural and anthropogenic selection of the material best adapted for local conditions. The effect of climatic factors on radial growth of beech has shifted during the 20th century. The effect of autumn temperature has weakened, likely due to warming; the effect of factors related to water deficit in summer has intensified that could be related to both, changes in climate and ageing. The observed climate-growth relationships suggested that conditions in winter have become suitable for beech, yet careful selection of sites/regions with appropriate hydrological conditions appear necessary to counteract the increasing effect of water deficit, hence to ensure productivity of future beech sites in Latvia.     

Estimation of extremely small field radiation dose for brain stereotactic radiotherapy using the Vero4DRT system

The purpose of this study was a dosimetric validation of the Vero4DRT for brain stereotactic radiotherapy (SRT) with extremely small fields calculated by the treatment planning system (TPS) iPlan (Ver.4.5.1; algorithm XVMC). Measured and calculated data (e.g. percentage depth dose [PDD], dose profile, and point dose) were compared for small square fields of 30 × 30, 20 × 20, 10 × 10 and 5 × 5 mm² using ionization chambers of 0.01 or 0.04 cm³ and a diamond detector. Dose verifications were performed using an ionization chamber and radiochromic film (EBT3; the equivalent field sizes used were 8.2, 8.7, 8.9, 9.5, and 12.9 mm²) for five brain SRT cases irradiated with dynamic conformal arcs.The PDDs and dose profiles for the measured and calculated data were in good agreement for fields larger than or equal to 10 × 10 mm² when an appropriate detector was chosen. The dose differences for point doses in fields of 30 × 30, 20 × 20, 10 × 10 and 5 × 5 mm² were +0.48%, +0.56%, −0.52%, and +11.2% respectively. In the dose verifications for the brain SRT plans, the mean dose difference between the calculated and measured doses were −0.35% (range, −0.94% to +0.47%), with the average pass rates for the gamma index under the 3%/2 mm criterion being 96.71%, 93.37%, and 97.58% for coronal, sagittal, and axial planes respectively.The Vero4DRT system provides accurate delivery of radiation dose for small fields larger than or equal to 10 × 10 mm².