Image fusion analysis of volumetric changes after interstitial low-dose-rate iodine-125 irradiation of supratentorial low-grade gliomas

The aim of this study was to compare the volumes of tumor necrosis, reactive zone and edema with the three-dimensional dose distributions after brachytherapy treatments of gliomas. The investigation was performed an average of 14.2 months after low-dose-rate (125)I interstitial irradiation of 25 inoperable low-grade gliomas. The prescribed dose was 50-60 Gy to the tumor surface. Dose planning and image fusion were performed with the BrainLab-Target 1.19 software. In the CT/ MRI images, the "triple ring" (tumor necrosis, reactive ring and edema) developing after the interstitial irradiation of the brain tumors was examined. The images with the triple ring were fused with the planning images, and the isodose curves were superimposed on them. The volumes of the three regions were measured. The average dose at the necrosis border was determined from the isodose distribution. For quantitative assessment of the dose distributions, the dose nonuniformity ratio (DNR), homogeneity index (HI), coverage index (CI) and conformal index (COIN) were calculated. The relative volumes of the different parts of the triple ring after the interstitial irradiation compared to the reference dose volume were the following: necrosis, 40.9%, reactive zone, 47.1%, and edema, 367%. The tumor necrosis developed at 79.1 Gy on average. The average DNR, HI, CI and COIN were 0.45, 0.24, 0.94 and 0.57, respectively. The image fusion analysis of the volume of tumor necrosis, reactive ring and edema caused by interstitial irradiation and their correlation with the dose distribution provide valuable information for patient follow-up, treatment options, and effects and side effects of radio therapy.     

No evidence of genetic benefits from extra-pair fertilisations in female sand martins (Riparia riparia)

Genetic parentage studies of socially monogamous birds reveal a widespread prevalence of extra-pair paternity. Variation in extra-pair paternity among individuals may depend on how different individuals benefit from extra-pair fertilisations and on the opportunity to pursue extra-pair copulations. A long-term study of sand martins (Riparia riparia) in Hungary allowed us to examine patterns of extra-pair fertilisations in a large colony of over 3,000 breeding pairs with many known age individuals. We used multi-locus DNA fingerprinting to determine whether extra-pair fertilisations occur when females are paired to (1) presumably low quality mates, or (2) genetically similar or dissimilar mates, and whether extra-pair fertilisations result in offspring of higher quality. Extra-paternal young were found in 38% of 47 broods and comprised 19% of 190 offspring. Males that lost paternity did not differ significantly from others in age or body condition. Social mates of broods containing extra-pair offspring did not differ in genetic similarity from pairs without extra-pair offspring. Furthermore, there was no significant difference in body condition between extra-pair young and their maternal half-siblings. We were unable to assign paternity and therefore cannot exclude the possibility that extra-pair males differed from the within-pair males they cuckolded, in age, body condition or genetic similarity with the female. We found a positive relationship between paternity losses and breeding density, suggesting that low breeding density may constrain opportunities for seeking extra-pair copulations.     

Time allocation of a parasitoid foraging in heterogeneous vegetation: implications for host-parasitoid interactions

1. Changing plant composition in a community can have profound consequences for herbivore and parasitoid population dynamics. To understand such effects, studies are needed that unravel the underlying behavioural decisions determining the responses of parasitoids to complex habitats. 2. The searching behaviour of the parasitoid Diadegma semiclausum was followed in environments with different plant species composition. In the middle of these environments, two Brassica oleracea plants infested by the host Plutella xylostella were placed. The control set-up contained B. oleracea plants only. In the more complex set-ups, B. oleracea plants were interspersed by either Sinapis alba or Hordeum vulgare. 3. Parasitoids did not find the first host-infested plant with the same speed in the different environments. Sinapis alba plants were preferentially searched by parasitoids, resulting in fewer initial host encounters, possibly creating a dynamic enemy-free space for the host on adjacent B. oleracea plants. In set-ups with H. vulgare, also, fewer initial host encounters were found, but in this case plant structure was more likely than infochemicals to interfere with the searching behaviour of parasitoids. 4. On discovering a host-infested plant, parasitoids located the second host-infested plant with equal speed, demonstrating the effect of experience on time allocation. Further encounters with host-infested plants that had already been visited decreased residence times and increased the tendency to leave the environment. 5. Due to the intensive search of S. alba plants, hosts were encountered at lower rates here than in the other set-ups. However, because parasitoids left the set-up with S. alba last, the same number of hosts were encountered as in the other treatments. 6. Plant composition of a community influences the distribution of parasitoid attacks via its effects on arrival and leaving tendencies. Foraging experiences can reduce or increase the importance of enemy-free space for hosts on less attractive plants.     

Effects of local and landscape scale and cattle grazing intensity on Orthoptera assemblages of the Hungarian Great Plain

The aims of this study were to test the influence of grazing intensity, effects of local and landscape parameters, and regional effects on orthopteran assemblages. We made our investigations on extensively and intensively grazed cattle pastures in three regions of the Hungarian Great Plain. The regions differed in landscape complexity; one region was situated in a structurally simple landscape with large landscape units, one in a structurally complex landscape with marshy patches and trees in the grasslands and one in a landscape with intermediate structural complexity. In each region we had seven pairs of differently managed grasslands, which differed in grazing intensity. Grasshoppers were recorded once in July 2003 using sweepnet catches and visual and acoustic observations in two 95 m long transects at each site (84 transects in total). Botanical surveys and measurements of other local factors were also made for each transect. After samplings, we digitised the most important land-use types using aerial photographs to produce landscape scale parameters within 100 and 500 m circles around every site. Analysing the management, regional, landscape and local effects on species richness with linear mixed models, we showed only strong significant regional differences. Linear mixed models for Orthoptera abundance yielded significant regional effects and marginal management effects. However, after including local and landscape parameters in a separate model a marginal local effect was found instead of a management effect in addition to the significant regional effect. Logistic regression models of 15 species also revealed the importance of local factors, particularly the importance of grass height, which is highly dependent on grazing intensity. We conclude that management intensity has indirect effects on Orthoptera species richness and abundance. Landscape scale parameters are also important, at least for some species.     

Physiological and Molecular Background of Maize Cold-Tolerance Enhancement with S-methylmethionine Salicylate

Low temperature is amongst the most influential abiotic stress factors, having deep impact on plant growth, yield and productivity. Studies on beneficial effects of certain biologically active substances, S-methylmethionine (SMM) and salicylic acid (SA) have provided a lot of valuable information regarding their role to counteract harmful effects of environmental stresses such as chilling. To obtain a more complex and stable defence compound with an extended range of stress-protective effect, the new derivative S-methylmethionine salicylate (MMS) was synthesised from the natural, biologically active substances SMM and SA. Since both original materials have complex stress-protective roles, the new compound was expected to combine the effects of original substances and to stabilise the unstable SMM in the new compound, thus providing an extended stress tolerance. Photosynthetic efficiency and accumulation of stress-related metabolites (polyamines and flavonoids) were measured in chilled and control plants, with and without MMS pretreatment, and expression changes of several genes involved in the cold stress response were analysed by quantitative real-time PCR (RT-qPCR) and a detailed microarray study. Our data show how the MMS combines the effect of SMM and SA on molecular level, causing numerous changes in the gene expression pattern and metabolite content. MMS gives rise to a better physiological condition, thus it could provide an alternative, environmental friendly way to enhance the plants defence mechanisms against stressors. As MMS is more stable than SMM, it promises easier, more long-lasting and more cost-effective usage in agriculture, with a complementing effect of SA.

     

Tracing the genetic origin of Europe's first farmers reveals insights into their social organization

Farming was established in Central Europe by the Linearbandkeramik culture (LBK), a well-investigated archaeological horizon, which emerged in the Carpathian Basin, in today''s Hungary. However, the genetic background of the LBK genesis is yet unclear. Here we present 9 Y chromosomal and 84 mitochondrial DNA profiles from Mesolithic, Neolithic Starčevo and LBK sites (seventh/sixth millennia BC) from the Carpathian Basin and southeastern Europe. We detect genetic continuity of both maternal and paternal elements during the initial spread of agriculture, and confirm the substantial genetic impact of early southeastern European and Carpathian Basin farming cultures on Central European populations of the sixth–fourth millennia BC. Comprehensive Y chromosomal and mitochondrial DNA population genetic analyses demonstrate a clear affinity of the early farmers to the modern Near East and Caucasus, tracing the expansion from that region through southeastern Europe and the Carpathian Basin into Central Europe. However, our results also reveal contrasting patterns for male and female genetic diversity in the European Neolithic, suggesting a system of patrilineal descent and patrilocal residential rules among the early farmers.     

Comparison of broad-scope assays of nucleotide sugar-dependent glycosyltransferases

Glycosyltransferases (GTs) are abundant in nature and diverse in their range of substrates. Application of GTs is, however, often complicated by their narrow substrate specificity. GTs with tailored specificities are highly demanded for targeted glycosylation reactions. Engineering of such GTs is, however, restricted by lack of practical and broad-scope assays currently available. Here we present an improvement of an inexpensive and simple assay that relies on the enzymatic detection of inorganic phosphate cleaved from nucleoside phosphate products released in GT reactions. This phosphatase-coupled assay (PCA) is compared with other GT assays: a pH shift assay and a commercially available immunoassay in Escherichia coli cell-free extract (CE). Furthermore, we probe PCA with three GTs with different specificities. Our results demonstrate that PCA is a versatile and apparently general GT assay with a detection limit as low as 1 mU. The detection limit of the pH shift assay is roughly 4 times higher. The immunoassay, by contrast, detected only nucleoside diphosphates (NDPs) but had the lowest detection limit. Compared with these assays, PCA showed superior robustness and, therefore, appears to be a suitable general screening assay for nucleotide sugar-dependent GTs.