Involvement of high-density lipoprotein in stimulatory effect of hormones supporting function of the bovine corpus luteum     

Skarzyński D  Młynarczuk J  Kotwica J 《Acta veterinaria Hungarica》2003,51(1):111-120

The hypothesis that epinephrine (noradrenaline, NA) enhances utilisation of high-density lipoproteins (HDL) by bovine luteal cells and that this process involves phospholipase (PL) C and protein kinase (PK) C intracellular pathway was tested. Luteal cells from days 2-4, 5-10 or 11-17 of the oestrous cycle were preincubated for 20 h. Subsequently DMEM/Ham's F-12 medium was replaced by fresh medium and the cells were treated for 6 h as follows: In Experiment I with HDL (5-75 micrograms cholesterol per ml), NA, isoprenaline (ISO) or luteinising hormone (LH). In Experiment II cells were incubated for further 24 h in deficient medium (without FCS) and next treated as in Experiment I. In Experiment III cells were stimulated with NA, ISO or LH alone and together with HDL. In Experiment IV cells were treated with PLC inhibitor (U-73122) or with PKC inhibitor (staurosporine) or stimulator (phorbol 12-myristrate 13-acetate) and with either NA, insulin or LH. Only luteal cells from days 5-10 of the cycle responded on HDL and beta-mimetics (P < 0.05). LH stimulated progesterone secretion from the luteal cells during all stages of the cycle (P < 0.001). Cells incubated in deficient medium and supplemented with HDL secreted as much progesterone as those stimulated by LH in all stages of the cycle. Beta-mimetics were unable to enhance the stimulatory effect of HDL. Blockade of PLC had no influence on progesterone secretion from cells treated with either NA or LH, but this did impair the stimulatory effect of insulin (P < 0.05). Similarly, blockade of PKC by staurosporine impaired (P < 0.05) the effect of insulin only but not that observed after LH or NA treatment. We suggest that: (a) noradrenergic stimulation does not enhance utilisation of cholesterol from HDL for progesterone secretion; (b) the fasting of luteal cells seems to activate enzymes responsible for the progesterone synthesis; (c) effect of NA on progesterone secretion from luteal cells does not involve the PLC-PKC pathway.  相似文献   

The influence of restraint immobilization stress on the concentration qf bioamines and cortisol in plasma of Pietrain and Duroc pigs     

Rosochacki SJ  Piekarzewska AB  Połoszynowicz J  Sakowski T 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2000,47(4):231-242

Forty-five Duroc (recognized as not susceptible to stress) and 34 Pietrain (susceptible to stress) pigs were subjected to immobilization stress in a prone position for 5, 15, 30 and 60 min. Plasma concentrations of epinephrine (E), norepinephrine (NE), dopamine (DA) and cortisol (C) were determined in response to restraint stress. The concentrations of E, NE and DA were different between the two strains of pigs (some significant interactions); the highest response was seen after 5 min of stress. The concentration of plasma C increased with duration of stress and there was a significant interaction between strain of animals and the time of stress. Our data substantiate the use of E, NE, DA and C as indicators of stress in swine as early as 5 min after exposure to the stressor. It is also shown that stress-susceptible Pietrain pigs had higher plasma concentrations of E, NE and DA than Duroc pigs.  相似文献   

An antisense coat protein gene confers immunity to potato leafroll virus in a genetically engineered potato   总被引：2，自引：0，他引：2  

Andrzej Pałucha  Włodzimierz Zagórski  Mirosława Chrzanowska  Danuta Hulanicka 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(3):287-293

The Bzura commercial potato cultivar was transformed by sense or antisense constructs which included the coat protein gene of potato leafroll virus RNA. In the sense construct, the coat protein gene was preceded by a leader sequence shorter than that in the subgenomic RNA formed in infected cells. The antisense construct consisted of a sequence complementary to the first 2020 nucleotides of the subgenomic RNA. Selected transformants expressing viral RNA were resistant to virus challenge by viruliferous aphids. In one line, expression of the antisense RNA prevented virus infection even after grafting with scions from infected plants and therefore this transformant might be regarded as virus immune.  相似文献   

Aluminosilicates at different levels in rye litter and feed affect the growth and meat quality of broiler chickens     

Banaszak  Mirosław  Biesek  Jakub  Adamski  Marek 《Veterinary research communications》2022,46(1):37-47

Veterinary Research Communications - Litter sanitation treatments and feed supplements that stimulate bird growth. The aim of this study was to analyse the effects of zeolite (z) and halloysite (h)...  相似文献   

Validation of a small-area method for estimating the spatial distribution of the degree of tree damage     

Rafał Podlaski 《European Journal of Forest Research》2004,123(3):229-237

This article presents a validation of a method, proposed in Podlaski (2003), for estimating the degree of tree damage. This method belongs to a group of small-area methods. To estimate the degree of tree damage in individual P₃ sub-blocks of the SINUS system of information on the natural environment, a classification based on the degree of defoliation was used. Spatial distribution of the degree of tree damage was estimated through unrestricted simple random sampling. The maximum total estimation error for proportions of fir and beech with a damage degree of zero, and also with second and third degrees jointly, reached a maximum of 35.6% for fir, and 33.8% for beech. P₃ sub-blocks characterised by the highest proportion of the healthiest trees (at least 15% being undamaged trees) occurred in patches in the case of fir, and in larger, compact areas in the case of beech. Because spatial diversification in the health of fir, and to a smaller degree in the case of beech, occurs at small scales, small-area methods for estimating tree condition are necessary. An analogous scheme, combining small-area with large-area methods (utilising sub-blocks of the network of large-area systems in a small-area inventory, and establishing a common database), could be used on a wider scale; for example, by supplementing the program of estimating tree health carried out by the United Nations Economic Commission for Europe (Lorenz et al. 2002) with local inventories.  相似文献   

Studies on insects and mites causing galls on the leaves of purple willow Salix purpurea L. in the Ojców National Park in Poland     

Małgorzata Skrzypczyńska 《Journal of pest science》2001,74(1):11-12

Analytical studies were conducted on the species composition of galls occurring on the leaves of Salix purpurea L. in the Ojców National Park in 1999?–?2000. The species composition of galls was identical in two consecutive years. Galls were caused by 5?species (a total of 480?galls). The most numerous species in both years was Pontania viminalis (L.). Index of occurrence frequency and Agrell's index of species co-existence have been calculated. This index reached the highest values in case of Pontania dolichura (Thoms.) and P. viminalis (L.) in 1999 as well as Phyllocolpa leucaspis (Tischb.) and P. viminalis (L.) in 2000.  相似文献   

Theoretical simulation of cutting edge wear when milling wood and wood based products     

Bolesław Porankiewicz 《Wood Science and Technology》2006,40(2):107-117

Theoretical simulation of cutting edge wearing when milling wood and melamine coated particle board based on stochastical and analytical methods is presented. Abrasion, high temperature corrosion (HTC) and frictional wearing effects are discussed. Results of computations show good correlation between the observed and predicted wear rate for three different experiments. Relations between predicted tool wear rate from HTC, content (C _CP) and size (S _CP) of particles of hard mineral contamination and density (D) of cut material is also presented and discussed.  相似文献   

Cohabitation of tree holes by ants and breeding birds in a temperate deciduous forest     

Sławomir Mitrus  Grzegorz Hebda  Tomasz Wesołowski 《Scandinavian Journal of Forest Research》2016,31(2):135-139

A previously unknown association of ants with birds breeding in tree holes is described. Ants Lasius brunneus Latreille (Hymenoptera: Formicidae) were found in c. 15% of nests of Parus major L. and Poecile palustris L. (Paridae) breeding in tree holes in the primeval deciduous forest located in the Bia?owie?a National Park (Poland). The ants preferably used holes located higher above the ground. As such holes are warmer than the unused holes or other nest sites, it is suggested that the ants cohabit holes utilized by the tits to gain thermal benefits.  相似文献   

The variation of tree-ring widths of Scots pine (Pinus sylvestris L.) affected by air pollution     

Sławomir Wilczyński 《European Journal of Forest Research》2006,125(3):213-219

Using eight populations of Scots pine growing in foothills of the Sudetes (southern Poland) as an example, the character and causes of annual ring variation in 1900–1999 were studied. The climate had a short-term effect on radial growth during the whole period investigated. A long-term decrease of radial growth occurred after 1960, but only in some localities. It was probably caused by non-climatic factors, most likely by industrial pollution. The decline of trees during that period is mainly evidenced by a high variation of width of annual rings, a small similarity of chronologies of annual ring widths, and a lack of signal years. After 1990, the tree recovery process was evident. It was most intensive in localities where the earlier stress was the most severe. Then, trees started to produce wide annual rings, homogeneity of the growth reaction increased, and the signal years began to occur.  相似文献   

High-speed steel tool wear during wood cutting in the presence of high-temperature corrosion and mineral contamination     

Bolesław Porankiewicz  Piotr Iskra  Jakub Sandak  Chiaki Tanaka  Karol Jóźwiak 《Wood Science and Technology》2006,40(8):673-682

Dulling of high-speed steel (HSS) cutting tools after milling five wood species has been analyzed. The wood investigated varied in mineral contamination, high-temperature corrosivity (HTC) and density (D). Experiments performed proved that up to date methods for evaluation of mineral contamination in wood should be improved. A new pipe-like form of mineral contamination particles was evidenced. The correlation between the presence of 3D aggregates of silica in wood and high content of K and Ca in the ash was established. Employing multivariable theoretical simulation method, the combined effect of mineral contamination, HTC and wood density on the tool dullness appeared to be a reasonable explanation of the results obtained.  相似文献