Production of giant mouse oocyte nucleoli and assessment of their protein content

Compared with advanced developmental stage embryos and somatic cells, fully grown mammalian oocytes contain specific nucleolus-like structures (NPB - nucleolus precursor bodies). It is commonly accepted that they serve as a store of material(s) from which typical nucleoli are gradually formed. Whilst nucleoli from somatic cells can be collected relatively easily for further biochemical analyses, a sufficient number of oocyte nucleoli is very difficult to obtain. We have found that isolated oocytes nucleoli fuse very efficiently when contact is established between them. Thus, well visible giant nucleoli can be obtained, relatively easily handled and then used for further biochemical analyses. With the use of colloidal gold staining, we estimated that a single fully grown mouse oocyte nucleolus contains approximately 1.6 ng of protein. We do believe that this approach will accelerate further research aiming at analyzing the composition of oocyte nucleoli in more detail.     

Seasonal colonisation of apple trees by ‘Candidatus Phytoplasma mali’ revealed by a new quantitative TaqMan real-time PCR approach

Apple proliferation (AP), caused by ‘Candidatus Phytoplasma mali’, is an economically important disease affecting many apple-growing areas in Europe. A new TaqMan real-time PCR assay was established for absolute quantification of ‘Ca. P. mali’ by using a single-copy gene of the host plant as a reference, which is amplified with the pathogen DNA in a single-tube reaction. Normalised estimates of phytoplasma concentration are ultimately expressed as the number of phytoplasma cells per host plant cell. The assay was used to monitor the ‘Ca. P. mali’ titre over the course of two growing seasons in roots and branches of symptomatic and asymptomatic but AP-positive apple trees. All 252 root samples from symptomatic and asymptomatic trees tested positive, with an average number of 59.8 ± 5.68 (standard error) and 55.1 ± 9.83 ‘Ca. P. mali’ per host cell, respectively. From the 378 shoot samples analysed, 81% of the symptomatic and only 20% of the asymptomatic samples were AP-positive with an average number of 9.4 ± 1.04 and 0.7 ± 0.13 ‘Ca. P. mali’ per host cell, respectively. This strengthens evidence that not the pathogen occurrence alone but the presence of a certain quantity of ‘Ca. P. mali’ in the aerial tree sections is involved in symptom expression. In addition, pronounced seasonality of the phytoplasma concentration was found, not only in branches, but also for the first time in roots of symptomatic and asymptomatic apple trees. Highest phytoplasma levels in roots were detected from December to May.     

杨农间作光能利用的研究

根据实测光强,利用作物和树木光－光合曲线中的最大光合速率和表观量子效率以及各物候期的叶面积系数、叶幕消光系数等参数,估算了杨农间作与单一农作物（对照）的光能利用率。结果表明,三种杨农间作模式的总光能利用率都高于对照,约可提高２７．５６％￣４８．６４％。间作田农作物的日累积光合量随日累积光量减少而降低,呈线性正相关。当相对光强〉６０％时,间作田农作物的光能利用率稍高于对照田农作物;相对光强〈５０％时     

Predicting depth translocation of base cations after forest liming: results from long-term experiments

Forest liming is a common measure to counteract soil acidification. In forest practice, lime is applied to the forest floor where it changes the chemical properties. However, little is known about the depth impact of liming and the depth translocation of lime components. To investigate the long-term impact of forest liming, several study plots have been established in the 1980s in Germany in stands with different site conditions. We analysed soil chemical data obtained during the last 28?years from 45 of the study plots. We examined the depth impact of liming and predicted the main factors responsible for the increase in Calcium (Ca) and Magnesium (Mg) stocks after liming in the mineral soil using multiple linear regression analyses (MLR). Stocks of Ca and Mg as well as base saturation (BS) showed a strong depth gradient with significant differences between limed and control plots down to 40?cm of the mineral soil. About 65–70?% of applied Ca and Mg were recovered in the forest floor and the upper 40?cm of the mineral soil. BS in 0–40?cm increased by a mean of 11?%. MLR models could explain 48–74?% of the variation in mean changes of Ca and Mg in 0–10, 10–20 and 20–40?cm soil depth when soil and climate variables, amount of applied lime and years after liming are included in the model. After testing the model robustness with a cross-validating procedure, we concluded that these models might be applied to many regions in Central Europe with comparable soil and climate conditions and thus, have widespread application.     

Production potential,biodiversity and soil properties of forest reclamations: Opportunities or risk of introduced coniferous tree species under climate change?

European Journal of Forest Research - In the time of ongoing climate change and the increasing area of post-mining landscape, the successful afforestation of reclamation sites by suitable adaptive...     

On the origin of phenolic compounds in the wood rays of Abies alba

Summary The development and localization of phenolic compounds in sapwood and heartwood of Abies alba Mill. have been studied using cytological and UV-microspectrophotometric methods. The synthesis of phenolic substances was apparently initiated in vesicles developing from rough ER of the ray parenchyma cells in sapwood. They are different from the phenolic material in the pit membrane and cell wall of heartwood. There was no indication to suggest that the polyphenols in the cell wall of heartwood were either derived from or identical with the phenolic substances in the lumina of ray cells.Dedicated to Prof. Dr. H. von Pechmann on the occasion of his 70th birthdayWe are thankful to Professor Dr. Walter Liese for his support and to Mrs. R. Schultze and Miss R. Endeward for technical assistance.     

The effect of fungicidal treatment on selected quality parameters of barley and malt

Protection of barley grain against contamination by fungi such as Fusarium spp., particularly by those producing mycotoxins, secondary metabolites with adverse health effects, is of principal importance. Fungicides applied immediately after full heading of spring barley is one method of direct protection. In this work, extensive two-year field experiments combined with a detailed chemical laboratory analysis (barley and malt) were performed with the aim to study the effect of previous crops, different fungicides, and other conditions on the selected barley and malt quality parameters (content of beta-glucans, pentosans, oxalic acid, deoxynivalenol, and gushing), while the main task was to follow the effect of the fungicide (used as a treatment to protect against pathogens, mostly Fusarium) on changes of the chemical composition in barley and malt, and gushing. It was found that the relationship between the studied factors and the parameters usually applied to the evaluation of barley and malt quality is quite complex and not straightforward. The responses show typical features of a multifactorial influence with both positive and negative correlations resulting in a decrease or increase in grain quality (concentrations of beta-glucans, pentosans, deoxynivalenol, and other studied parameters). The role of previous crops was also found to be important. The fungicides should be applied at the time of heading but not at the very beginning of this period.