Expression of aromatase and oestrogen receptors in reproductive tissues of the stallion and a single cryptorchid visualised by means of immunohistochemistry

Androgen metabolism may proceed to amplify the action of testosterone by its aromatisation to oestradiol. Recently, a growing body of evidence suggests a role of oestrogens in the male reproductive tract via their specific oestrogen receptors (ERs). In order to check whether androgens are converted to oestrogens in the testis, epididymis and prostate of the stallion, the expression of aromatase was visualised by means of immunohistochemistry. Moreover, to show the cellular targets for oestrogens the presence of oestrogen receptor alpha (ERalpha) and oestrogen receptor beta (ERbeta) was demonstrated in these tissues. Finally, to show whether naturally occurring cryptorchidism has any influence on the localisation of aromatase and distribution of ERs, the reproductive tissues of a single horse, bilaterally cryptorchid, were also taken for this study. The results demonstrated that aromatase and ERs are ubiquitously distributed throughout the male reproductive tract, what indicates a putative role of oestrogens in modulating the function of the reproductive tissues of the stallion. In the cryptorchid horse the increase in conversion of androgen to oestrogen was observed as manifested by aromatase overexpression. This is the first report showing the cellular site of oestrogen biosynthesis not only in the testis but also in the epididymis and prostate of sexually mature stallion and a single, adult cryptorchid.     

Susceptibility of potato varieties and advanced breeding lines (Solanum tuberosum L.) toPhytophthora infestans (Mont.) de Bary in greenhouse screenings

Late blight (Phytophthora infestons (Mont.) de Bary) has re-emerged as an important pathogen of the cultivated potato (Solanum tuberosum subsp.tubero-sum L.) in North America. The purpose of this study was to evaluate the relative susceptibility of potato germplasm in the greenhouse in order to initiate a breeding program for resistance to the US-8/A2 mating type which is the more aggressive and prevalent strain of late blight. Whole plants of 147 cultivars and breeding lines were evaluated. Percent plant area infection was visually assessed. Seven days after inoculation, infection ranged from 0 to 100% and the overall mean was greater than 50%. Two-thirds of the cultivars and breeding lines tested were very susceptible to the US-8 genotype. The highest resistance was identified in the somatic hybrids betweenS. tuberosum andS. bulbocastanum and their backcross derivatives. Pike and Snowden were less susceptible than the other North American cultivars. Zarevo was most resistant among the European cultivars. Seven of the advanced breeding lines were equivalent to Zarevo in infection levels. The host plant resistance identified among the material tested in this study can be used by breeding programs to develop improved cultivars with resistance to US-8 genotypes of late blight.     

Application of fracture mechanics for energetic effects predictions while wood sawing

In the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specific cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, cutting forces (or power—more interesting from energetic point of view) could be considered from a point of view of modern fracture mechanics. Cutting forces may be employed to determine not only toughness but also shear yield strength, which are then applied in the models. Furthermore, forecasting of the shear plane angle for the cutting models, which include fracture toughness in addition to plasticity and friction, broadens possibilities of energetic effects modelling of the sawing process even for small values of the uncut chip. Mentioned models are useful for estimation of energetic effects of sawing of every kinematics. However, for band saws and circular sawing machines, the chip acceleration power variation as a function of mass flow and tool velocity ought to be included in analysis of sawing at larger cutting speeds.     

Nutritive value of marketable heads and outer leaves of white head cabbage cultivated at different nitrogen rates

The effect of different nitrogen treatments (100–400?kg?N?ha^?1) on yield and quality of marketable cabbage heads and outer green leaves (waste fraction) of two cultivars of Brassica oleracea convar. capitata var. alba L. grown in two years field experiment was studied. During harvest, the marketable cabbage heads and the outer leaves (not adjacent leaves of cabbage) were removed; total and marketable yield of cabbage were evaluated as well as nutritive value was determined based on content of some components, that is, dry matter, ascorbic acid, soluble polyphenols, total flavonoids, nitrates, total nitrogen and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH). The study showed a significant effect of nitrogen fertilization on the total and marketable yield of the tested cultivars of cabbage. The weight of total cabbage heads was increasing according to higher nitrogen fertilization from 100 up 400?kg?N?ha^?1 for both cultivars. The outer leaves of cabbage characterized by a significantly higher nutritive value compared with marketable head, which is supported by several-fold higher content of total flavonoids, soluble polyphenols and over the 100% increase in ascorbic acid content. Although the outer green leaves of cabbage are discarded after harvesting, they possess high nutritive potential which can be practically used or transformed into an added value product.     

Early generation selection methods used in Polish potato breeding

Polish potato breeding involves two stages: development of parental lines and their use in the development of new cultivars. In the breeding of new cultivars, early generation selection is based mainly on visual discrimination of superior genotypes. Careful evaluation of clones is done in later generations. In parental line breeding the whole selection procedure is completed in early generations. Experience gained in early generation selection for virus resistance, yield, and dry matter content has been summarized. Evidence has also been presented that evaluation of individual tubers makes possible an inexpensive selection of numerous genotypes for several important characters.     

Se-enriched mycelia of Pleurotus ostreatus: distribution of selenium in cell walls and cell membranes/cytosol

The incorporation of Se to fungi has been studied, focusing on element distribution among different cellular compartments and, in particular, polysaccharide structures contained in cell walls. Se-enriched mycelia of Pleurotus ostreatus were obtained in submerged cultures. The incorporation of selenium from the growth medium to mycelia was observed with the relative distribution between cytosol plus cell membranes fraction (CCM) and cell walls fraction (CW) of about 44 and 56%, respectively. CCM fractions were analyzed by size exclusion chromatography with on-line UV (280 nm) and ICP-MS detection (80Se). The results obtained showed selenium binding to components of different molecular masses (about 24% of total selenium coeluted with the compounds of molecular mass > 10 kDa). A polysaccharide-containing fraction of mycelia was treated alternatively with Tris-HCl at pH 7.5 or with chitinase. Better solubility and increased contribution of low molecular mass compounds were observed in chitinase extracts (UV detection), confirming the degradation of polysacharides by the enzyme. The total area under the ICP-MS chromatogram of chitinase extract was 2 times higher with respect to the area for Tris-HCl extract. Furthermore, the relative contribution of selenium in the low molecular mass fraction (molecular mass < 1 kDa) in chitinase extract was 72% as compared to 45% in Tris-HCl extract (based on peak area measurements with respect to total area under the chromatogram). The results obtained suggest selenium binding to chitin-containing polysaccharide structures in fungi cell walls.     

A comparison of different survey methods for assessing gap parameters in old-growth forests

Examining the actual state of canopy gaps in forests is critically important for evaluating forest community structure and dynamics, and for comparing gap disturbance regimes in different forests. We, therefore, re-examined our own previously published data from three studies of three different gap survey methods - the Belt transect method, the canopy coverage census method, and an aerial photography method - in order to ascertain how gap parameters (area, size and density of gaps, and related gap characteristics) obtained from these methods differ from each other. We found that the Belt transect method is easy to apply and practical in the field, and the method used for gap measurement is simple. Mean gap size and size distribution obtained using the Belt transect method were not different statistically from those of the other gap survey methods, and quantified gap parameters were in the range recorded for other forests of the world. For preliminary studies of gap dynamics in different forest types, an easy, speedy and workable gap survey method is needed. In addition, surveying a large number of gaps and a large area improve the accuracy of the method. We conclude that the Belt transect method is most suitable method for preliminary gap surveys in the field.     

Effect of tillage and crop management on runoff,soil erosion and organic carbon loss

Proper management of soil organic matter is an important issue in the context of sustainable agriculture. The intensification of production and the loss of organic carbon associated with agriculture reduce the efficiency of production and the quality of the environment, especially in relation to areas exposed to erosion. The aim of this study was to determine the impact of specific tillage systems and plant cover on the organic carbon losses, as well as on runoff and soil losses, over a 6-year study period following the introduction of no-till. The first factor in the experiment was the tillage system: conventional tillage (CT) and no-till (NT). The second factor was plant cover: horse bean, spring wheat and winter oilseed rape. The results showed that runoff was 4.3 ± 0.6% higher under NT than under CT, while soil loss was 66.8 ± 2.7% lower under NT than under CT. Compared to CT, NT limited the total organic carbon losses by an average of 46.0 ± 2.9% and organic carbon bound with sediment losses by 53.2 ± 0.7%, whereas for dissolved organic carbon, there were no significant differences for the tillage systems. The anti-erosion effectiveness of NT was lower in the first year, but it increased in subsequent years after the introduction of this tillage system. Plant cover also had a significant impact on organic carbon losses and soil protection. The crops were ranked according to runoff, soil losses and organic carbon losses in the following order from lower to higher losses: winter oilseed rape > spring wheat > horse bean.     

Effect of selected herbicides on yielding and malting quality of spring barley cultivars

The aim of the study was to determine the effect of herbicides on yields, yield components and malting quality of the grains of barley cultivars. Literature worldwide lacks works on the impact of herbicides on the brewing quality of barley. This work presents the results of field experiments and laboratory studies concerning the evaluation of the impact of herbicides, differing in terms of an active substance, on the yields, weed control and malting quality of selected cultivars of barley. The research was conducted in Poland. The herbicides affected the increase in grain yields of barley, due to their high effectiveness of weed control, resulting in an increase in the number of ears per area unit. Certain herbicides increased grain protein content and grain filling. As for malt extractivity, Kolbach index, Q index, diastatic power and beta-glucans content in wort, there were interactions between herbicides and cultivars. The impact of herbicides on parameters varied depending on cultivars. The herbicides, especially Chwastox Turbo 340 SL (MCPA?+?dicamba) and Secator 125 OD (amidosulfuron?+?iodosulfuron-methyl-sodium), worsened several (not many) malt quality parameters, depending on cultivars, but it did not contribute to disqualifying malting quality of grains. Therefore, all tested herbicides can be recommended for use by farmers.     

Propagation of scrapie in peripheral nerves after footpad infection in normal and neurotoxin exposed hamsters

As is known from various animal models, the spread of agents causing transmissible spongiform encephalopathies (TSE) after peripheral infection affects peripheral nerves before reaching the central nervous system (CNS) and leading to a fatal end of the disease. The lack of therapeutic approaches for TSE is partially due to the limited amount of information available on the involvement of host biological compartments and processes in the propagation of the infectious agent. The in vivo model presented here can provide information on the spread of the scrapie agent via the peripheral nerves of hamsters under normal and altered axonal conditions. Syrian hamsters were unilaterally footpad (f.p.) infected with scrapie. The results of the spatiotemporal ultrasensitive immunoblot-detection of scrapie-associated prion protein (PrP(Sc)) in serial nerve segments of both distal sciatic nerves could be interpreted as a centripetal and subsequent centrifugal neural spread of PrP(Sc) for this route of infection. In order to determine whether this propagation is dependent on main components in the axonal cytoskeleton (e.g. neurofilaments, also relevant for the component ;a' of slow axonal transport mechanisms), hamsters were treated -in an additional experiment- with the neurotoxin beta,beta-iminodiproprionitrile (IDPN) around the beginning of the scrapie infection. A comparison of the Western blot signals of PrP(Sc) in the ipsilateral and in the subsequently affected contralateral sciatic nerve segments with the results revealed from IDPN-untreated animals at preclinical and clinical stages of the TSE disease, indicated similar amounts of PrP(Sc). Furthermore, the mean survival time was unchanged in both groups. This in vivo model, therefore, suggests that the propagation of PrP(Sc) along peripheral nerves is not dependent on an intact neurofilament component of the axonal cytoskeleton. Additionally, the model indicates that the spread of PrP(Sc) is not mediated by the slow component ;a' of the axonal transport mechanism.