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61.
62.
Katarzyna Hrynkiewicz Christel Baum Peter Leinweber 《European Journal of Soil Biology》2009,45(2):168-175
Low supply of the nutrients nitrogen (N) and phosphorus (P) limit plant growth and spreading, and increase the plant-microbial nutrient competition in subarctic and arctic regions. We investigated the mycorrhizal community structure of a polar shrub willow (Salix polaris) and the microbial turnover in its rhizosphere to explore the adaptation of a mycorrhizal plant in the subarctic tundra. The ectomycorrhizal colonisation ranged from 35 to 64% of the fine root tips and decreased with an increasing soil C/N ratio. In total, 16 ectomycorrhizal morphotypes were found under S. polaris (eight to 13 morphotypes per site, five morphotypes at all four sites). Cenococcum sp. was the most common EM fungus (32% of the ectomycorrhizal fine roots). The abundance of Cenococcum sp. increased with an increasing organic matter content and N/P ratio in the soil. Arbuscular mycorrhizal colonisation of S. polaris was absent or less than 1% of the fine root length. Microbial biomass P accounted for 21–75% of the organic soil P and 6–49% of the total soil P. Microbial biomass P, alkaline and acid phosphatase activities in the rhizosphere increased with increasing soil N concentration. We conclude that a higher N supply decreases the diversity in the mycorrhizal community on polar willows and increases the role of P turnover from the soil microbial biomass for the nutrient supply. 相似文献
63.
Grażyna Furgała-Selezniow Andrzej Skrzypczak Dariusz Kucharczyk Roman Kujawa Andrzej Mamcarz Daniel Żarski Katarzyna Targońska 《Aquaculture International》2014,22(1):41-52
Feeding and food selection of burbot (Lota lota L.) larvae reared in illuminated cages were studied. The experiment was carried out in mesotrophic Lake Maróz, in north-eastern Poland, for 6 weeks in two successive years. The initial stocking density was 1,250 larvae (20 DPH) per cage. Food selection according to the zooplankton groups (Rotifera, Cladocera and Copepoda) and length classes was expressed by the Strauss linear selectivity index (L). Zooplankton species composition in the lake was similar in the two seasons of the study and organisms shorter than 0.5 mm prevailed in the plankton. The mean number of prey found in burbot alimentary tracts increased from about 40 up to over 200 during the course of the study. A very large inter-individual variation in the amount of food organisms consumed by fish was noted. Analysis of the values of the Strauss food selectivity index shows that at the beginning of the first year of the experiment, burbot larvae preferred copepods, most numerous in the environment at that time; later, fish tended to select cladocerans. In the second year of the study, fish more often ate copepods, irrespective of their quantities in the environment. During the whole study, reared burbot larvae did not eat rotifers, even when they were numerous in cages. Similarly to the rotifers, the smallest planktonic organisms, measuring up to 0.5 mm in length, were typically neglected by fish, while the 0.6–1.0 mm group was most frequently selected. There were also considerable individual differences between particular burbot specimens in their food preferences. 相似文献
64.
Katarzyna Kubiak Miłosz Tkaczyk Monika Małecka Zbigniew Sierota 《Archives of Agronomy and Soil Science》2017,63(3):427-441
Sawdust and wood residues are considered to be stimulators of microbiological change in soil and could be used in post-arable sites designed for afforestation. In this study, we discuss changes in bacteria numbers within selected groups in relation to soil type (arable and forest) and method of sawdust application. Sawdust was spread along planting rows and mixed with the soil or put directly under roots of planted seedlings. Applying sawdust under the roots increased the number of cellulolytic bacteria in all experimental treatments. On post-arable soil, adding sawdust in rows increased the number of copiotrophic bacteria and reduced the number of fluorescent bacteria and actinomycetes (ACT). In control forest soils, the number of copiotrophic, oligotrophic and spore-forming bacteria decreased simultaneously with increased ACT in all treatments. The number of fluorescent bacteria increased when sawdust was applied on forest sites under planted trees and decreased when sawdust was spread in planting rows. Oligotrophic bacteria also decreased in the latter case. We present a list of bacteria identified by DNA – 16S rRNA gene sequences. Adding sawdust to arable soils significantly changed the quantitative and qualitative composition of microbial communities. 相似文献
65.
Dirofilaria repens—An etiological factor or an incidental finding in cytologic and histopathologic biopsies from dogs 下载免费PDF全文
Katarzyna Paździor‐Czapula Iwona Otrocka‐Domagała Patrycja Myrdek Mateusz Mikiewicz Michał Gesek 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2018,47(2):307-311
Dirofilaria repens is an endemic, zoonotic parasite of carnivores, causing subcutaneous dirofilariasis, which is mostly asymptomatic. The aim of this study was to describe 22 cases of canine subcutaneous dirofilariasis. The cytologic and histopathologic samples were collected from dogs, which presented with various clinical signs such as cutaneous/subcutaneous nodules, hydropericardium, ascites, and lymphadenomegaly. The cytologic or histopathologic examination revealed purulent, pyogranulomatous, granulomatous or eosinophilic dermatitis/panniculitis, and the presence of D repens microfilariae or adults. The microfilariae or adults were also found incidentally in neoplastic cutaneous or subcutaneous tumors and in a sialocele. For the first time, microfilariae were also detected and described in pericardial and abdominal effusions and in enlarged reactive lymph nodes. Although it is well known that D repens can cause dermatitis and panniculitis in dogs, no previous reports of D repens microfilariae in body cavity fluids were found. The role of this parasite in the accumulation of body cavity fluid or in reactive lymphadenomegaly requires further investigation. Due to its zoonotic potential, and apparently underestimated pathogenicity, each case of canine subcutaneous dirofilariasis should be treated. 相似文献
66.
Daniel Żarski Katarzyna Targońska Sławomir Krejszeff Maciej Kwiatkowski Krzysztof Kupren Dariusz Kucharczyk 《Aquaculture International》2011,19(6):1105-1117
Two experiments were conducted into the rearing of crucian carp larvae under controlled conditions in an experimental closed
water system. In both cases, the rearing lasted 21 days. The first experiment concerned the initial stocking density (from
50 to 600 individuals per l), whilst the second one studied the first food offered (two types of Artemia nauplii, decapsulated Artemia cysts and three types of commercial feeds) which were applied at the moment of exogenous feeding commencement. The best results
were obtained using 50 larvae per l, whilst there were no significant differences within the range 200–600 larvae per l. The
application of dry feed had a negative influence on the survival and other parameters. The highest survival rate was found
in the groups fed with freshly hatched Artemia naupli. The results obtained indicate that the rearing of crucian carp larvae may be successfully conducted in very high
stocking densities. However, the very high sensitivity of crucian carp larvae to the type of food offered during the initial
days of life should be taken into account. The data presented in this article could be very useful in crucian carp larviculture. 相似文献
67.
Jean Bernard Diatta Witold Grzebisz Katarzyna Wiatrowska 《Soil Science and Plant Nutrition》2013,59(6):899-908
Abstract The simultaneous incorporation of heavy metals into the soil is still a matter of great concern. Interaction (competitive sorption) between these metals and the soil solid phase may result in a deterioration of soil quality which relies basically on amounts of alkaline cations saturating soils sorptive complex. Results of this study indicate that Pb, Cu, C d, and Zn have induced solution pH decreases which were more intensive at highest metal loading rates. Partition parameters (Kd)-based sequences showed that Pb and Cu were more competitive than Cd and Zn and the overall selectivity sequence followed: Pb > Cu > Cd > Zn. Metal loadings and their competitive sorption have led to a strengthened displacement of alkaline cations (i.e. Ca2+, Mg2+, K+, Na+), especially of Ca2+ as a factor “stabilizing” soil sorptive complex. Such metals impact jointly with soils acidification are of great environmental concern since tremendous amounts of alkaline cations (especially Ca2+) may be potentially leached out, irrespective of the degree of soil contamination, as evidenced in the current study. High and positive ΔG values implied that the studied soils were characterized by generally low concentrations of exchangeable potassium which required high energy to get displaced (desorbed). Further studies on heavy metal uncontaminated or contaminated areas should be undertaken to provide with data which should be used for predictions on changes related to soil buffering capacity as impacted by heavy metal inputs. 相似文献
68.
The effect of 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA), and their derivatives: phenol, 2,4-dichlorophenol (2,4-DCP), 2,4-dimethylphenol (2,4-DMP), and catechol on the activity of acetylcholinesterase (AChE, EC 3.1.1.7) in human erythrocytes was studied. Phenol, MCPA, and 2,4-DMP did not significantly change AChE activity in human erythrocytes (in vitro). Decrease of AChE activity was observed under the highest applied dose of 2,4-D—500 and 1000 ppm. Decrease of AChE activity exposed to 2,4-DCP and catechol was noted and depended on the doses of applied compounds. The relationship between activities and substrate concentrations (curves) was analyzed for reactions of acetylcholinesterase. Catalytic constants Km and Vmax were calculated from the Michaelis curve. Statistically significant decrease of Vmax and Km was observed in the activity of AChE incubated with 2,4-DCP and catechol, revealing mixed inhibition type of AChE inhibition (this compound may affect not only on enzyme but also on complex ES as well). 2,4-D decreases Vmax but do not change Km value, what reveals non-competitive type of AChE inhibition by this compounds. Non-competitive inhibition does not depend on the substrate concentrations but only on the inhibitor concentration and its Ki value, characterizes the affinity of inhibitors towards enzyme. In conclusion, changes of AChE activity upon 2,4-D, 2,4-DCP, and catechol are the consequences of direct interactions between compounds and the enzyme and indirect via membrane modification and increase of Reactive Oxygen Species. 相似文献
69.
70.
The degradation of seven potential wood preservatives based on imidazolium compounds (ICs) and quaternary ammonium compounds (QACs) with a modified anion structure by mould fungi was determined using soil-block method. Experiments were carried out on Scots pine (Pinus sylvestris L.) wood. Two-phase titration and high-performance liquid chromatography (HPLC) method were used to detect and quantify the degradation products. The performed soil-block tests showed that the ICs and QACs with alkoxymethyl substituents were leached from the experimental wood when in contact with moist soil and revealed their fungal detoxification by mould fungi, especially by Gliocladium roseum. The degree of biological decomposition of new compounds was higher than didecyldimethylammonium chloride and didecylmethylpoli(oxyethyl)ammonium propionate. The observations of the colonization by mould fungi were made using the scanning electron microscope (SEM). Decay of treated wood by mould fungi showed its tolerance to QACs. 相似文献