The response of HEK293 cells transfected with bovine TLR2 to established pathogen-associated molecular patterns and to bacteria causing mastitis in cattle     

Farhat K  Sauter KS  Brcic M  Frey J  Ulmer AJ  Jungi TW 《Veterinary immunology and immunopathology》2008,125(3-4):326-336

Toll-like receptors (TLRs) are key sensors of pathogen-associated molecular patterns (PAMPs). Their role in immunity is difficult to examine in species of veterinary interest, due to restricted access to the knockout technology and TLR-specific antibodies. An alternative approach is to generate cell lines transfected with various TLRs and to examine the recognition of PAMPs or relevant bacteria. In this report, we examined whether recognition of various PAMPs and mastitis-causing bacteria is achieved by transfection of recombinant bovine TLR2 (boTLR2). Therefore, human embryonic kidney (HEK) 293 cells were transfected by whole boTLR2. A clonal analysis of stably transfected cells disclosed variable recognition of several putative TLR2 agonists although expressing similar amounts of the transgene and endogenous TLR6. One clone (clone 25) reacted by copious interleukin-8 (IL-8) production to several stimulants of TLR2 such as di-palmitoylated cysteyl-seryl-lysyl-lysyl-lysyl-lysine (Pam2), a biochemical preparation of lipoteichoic acid from Staphylococcus aureus, a commercial preparation of peptidoglycan from S. aureus, and heat-killed Listeria monocytogenes (HKLM). TLR2-dependent induction of IL-8 release was stronger in medium containing human serum albumin than in medium containing fetal calf serum. Clone 25 cells responded to high concentrations of S. aureus and to Escherichia coli causing mastitis, but not to Streptococcus uberis and to Streptococcus agalactiae which also cause mastitis. Stimulation by S. aureus was relatively weak when compared (i) with stimulation of the same cells by HKLM and PAMPs derived from S. aureus, (ii) with a clone stably transfected with TLR4 and MD-2 and stimulated by E. coli causing mastitis, and (iii) with interferon-gamma-costimulated bovine macrophages stimulated by S. aureus and S. agalactiae. Thus, clone 25 is suitable for studying the interaction of putative TLR2 agonists with bovine TLR2-transfected cells, provides a cell to search for TLR2-specific antibodies, and is a tool for studying the interaction of TLR2 with bacteria causing disease, e.g. mastitis, in cattle.  相似文献   

Comparison of Equine Adipose Tissue-Derived Stem Cell Behavior and Differentiation Potential Under the Influence of 3% and 21% Oxygen Tension     

Katja Shell  DVM  Oksana Raabe  Christian Freitag  Arne Ohrndorf  Hans-Jürgen ChristSabine Wenisch  DVM  Stefan Arnhold 《Journal of Equine Veterinary Science》2013

Equine multipotent mesenchymal stem cells can be isolated from different tissues and are capable of differentiating into various organ progenitor cells. Physiological oxygen conditions in diverse tissues in vivo are hypoxic, even when standard culture conditions are normoxic. Here, equine adipose tissue-derived stem cells were used to analyze their behavior and differentiation potential into the adipogenic, osteogenic, and chondrogenic lineage under 3% and 21% oxygen tension. Hypoxia-inducible factor-1α is an indicator for hypoxic stress sensed by cells. Its expression was similar under both oxygen conditions, which could be a sign for low oxygen tension being sensed as normoxic by those stem cells. Furthermore, it was observed that hypoxia inhibits cell proliferation. Adipogenesis and chondrogenesis showed better results under 3% oxygen; for osteogenesis, an oxygen tension of 21% was more effective. This knowledge may help to improve conditions of stem cell differentiation and consequently their application in tissue engineering.  相似文献   

Polyclonal antibody–based immunohistochemical detection of intraleukocytic Theileria parasites in roan and sable antelopes     

Sarah J. Clift  Bernat Martí-Garcia  Rephima M. Phaswane  Emily P. Mitchell  Antoinette I. Josemans  Ilse Vorster  Katja N. Koeppel  Jeanni Fehrsen 《Journal of veterinary diagnostic investigation》2021,33(6):1079

Theileria parasites commonly infect African wild artiodactyls. In rare roan (Hippotragus equinus) and sable (H. niger) antelopes, Theileria sp. (sable)-associated calf mortalities constrain breeding programs. The pathogenicity of most leukocyte-transforming Theileria spp. originates in their invasion of and multiplication in various mononuclear leukocytes, the transformation of both infected and uninfected leukocytes, and their infiltration of multiple organs. Understanding the pathogenesis of theileriosis can be improved by the use of immunohistochemistry (IHC) to identify the localization of the parasites in tissue sections. Our aim was to develop a reproducible IHC assay to detect leukocyte-associated Theileria parasites in formalin-fixed, paraffin-embedded roan and sable tissues. Polyclonal antibodies were purified from the sera of 5 roans from an area endemic for Theileria sp. (sable) and tested for IHC reactivity in 55 infected and 39 control roan and sable antelopes, and for antigen and species cross-reactivity in an additional 58 cases. The 3 strongest antibodies consistently detected intraleukocytic theilerial antigens in known positive cases in roan and sable antelopes, and also detected other Theileria spp. in non-hippotraginid wild artiodactyl tissues. The antibodies did not cross-react with other apicomplexan protozoa, with the exception of Cryptosporidium. Given that PCR on its own cannot determine the significance of theilerial infection in wild ruminants, IHC is a useful laboratory test with which to confirm the diagnosis in these species.  相似文献   

The effects of temperature on the development,fecundity and mortality of Eretmocerus warrae: is Eretmocerus warrae better adapted to high temperatures than Encarsia formosa?     

Tao Wang  Michael Anthony Keller  Katja Hogendoorn 《Pest management science》2019,75(3):702-707

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Risikofolgeabschätzung für den Einsatz mikrobieller Antagonisten: Gibt es Effekte auf Nichtzielorganismen?     

Gabriele Berg  Rita Grosch  Katja Scherwinski 《Gesunde Pflanzen》2007,59(3):107-117

Biological control of phytopathogenic fungi using antagonistic microorganisms is an environmentally friendly alternative in plant protection. However, possible non-target effects of the applied antagonists on ecologically important soil-microbes need to be considered. Therefore, the aim of this study was to analyse the effect of biological control agents (BCAs) on non-target microbes in the field. Whereas the bacterial BCAs Serratia plymuthica HRO-C48 and Streptomyces sp. HRO-71 were applied to control the pathogen Verticillium dahliae on strawberry and potato, the bacterial strains Pseudomonas trivialis 3Re2-7, P. fluorescens L13-6-12, S. plymuthica 3Re4-18 and the fungal antagonists Trichoderma reesei G1/8 and T. viride G3/2 were introduced to control Rhizoctonia solani on lettuce and potato. As the analysed BCAs belong to different microbial groups like grampositive (HRO-71) and gramnegative (HRO-C48, L13-6-12, 3Re2-7, 3Re4-18) bacteria or the ascomycota (G1/8, G3/2) and originated from different micro-habitats like the rhizosphere or the endorhiza, general conclusion could be drawn from our results. After BCA treatment we did not observe any long-term effect on the plant-associated microbes in any tested pathosystem. Therefore, no sustainable risks could be seen for the indigenous micro-organisms. Our new findings may help to improve the development as well as the registration procedures of future microbial plant protection products.  相似文献   

Equine Urolithiasis     

Katja F. Duesterdieck-Zellmer 《Veterinary Clinics of North America: Equine Practice》2007

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Clones or no clones:genetic structure of riparian Populus euphratica forests in Central Asia     

Katja KRAMP  Thomas SCHMITT  Petra LANG  Michael JESCHKE  Philipp SCHFER  Dustin KULANEK  ZHANG Ximing  YU Ruide  Frank M THOMAS 《干旱区科学》2018,10(5):750-766

Many riparian(Tugai) forests growing along rivers in arid and hyper-arid regions of Central Asia are dominated by the Euphrates poplar(Populus euphratica). Besides generative reproduction, which is only possible upon flooding events and at a distance to the groundwater of less than 2 m, this phreatophytic tree species also reproduces vegetatively by forming clones that can cover land surface areas of several hectares. Along a gradient of groundwater distances, we investigated whether the fraction of clones in P. euphratica stands(1) increases with increasing distance to the water table;(2) is higher if supplied with water via river cut-offs; and(3) approaches 100% at a short distance to the groundwater, but at high salt concentrations in the upper soil layers, which would prevent germination and establishment of seedlings. AFLP(Amplified Fragment Length Polymorphism) analyses were conducted on leaf samples taken from mature P. euphratica trees growing at the fringes of the Taklimakan Desert in stands with different distances(2–12 m) to the groundwater at two plots at the middle and the lower reaches of the Tarim River and in a stand close to Ebinur Lake, Xinjiang, China. Genetic diversity was large among plots, but considerably smaller within plots. We found the highest genetic diversity(caused by regeneration from seeds) at plots that have a short distance to the groundwater or are supplied with additional water. There was no significant relationship between groundwater distance and clonal fraction. All investigated trees at the saline Ebinur Lake site belonged to one single clone. Our results demonstrate that the genetic pattern of this widespread species is not easily predictable even over small distances as it is a result of a complex interplay of stand history and dispersal of propagules(pollen, seeds, and vegetative diaspores) by wind and water. In conservation and restoration schemes, P. euphratica stands with a high genetic diversity and stands that grow at short distances to the water table and are regularly subjected to flooding(which favors generative over clonal reproduction) should be prioritized.  相似文献   

Do interactions with soil organisms mediate grass responses to defoliation?     

Katja Ilmarinen  Juha Mikola  Mauritz Vestberg 《Soil biology & biochemistry》2008,40(4):894-905

Defoliation-induced changes in grass growth and C allocation are known to affect soil organisms, but how much these effects in turn mediate grass responses to defoliation is not fully understood. Here, we present results from a microcosm study that assessed the role of arbuscular mycorrhizal (AM) fungi and soil decomposers in the response of a common forage grass, Phleum pratense L., to defoliation at two nutrient availabilities (added inorganic nutrients or no added nutrients). We measured the growth and C and N allocations of P. pratense plants as well as the abundance of soil organisms in the plant rhizosphere 5 and 19 d after defoliation. To examine whether defoliation affected the availability of organic N to plants, we added ¹⁵N-labelled root litter to the soil and tracked the movement of mineralized ¹⁵N from the litter to the plant shoots.When inorganic nutrients were not added, defoliation reduced P. pratense growth and root C allocation, but increased the shoot N concentration, shoot N yield (amount of N in clipped plus harvested shoot mass) and relative shoot N allocation. Defoliation also reduced N uptake from the litter but did not affect total plant N uptake. Among soil organisms, defoliation reduced the root colonization rates of AM fungi but did not affect soil microbial respiration or the abundance of microbe-grazing nematodes. These results indicate that interactions with soil organisms were not responsible for the increased shoot N concentration and shoot N yield of defoliated P. pratense plants. Instead, these effects apparently reflect a higher efficiency in N uptake per unit plant mass and increased relative allocation of N to shoots in defoliated plants. The role of soil organisms did not change when additional nutrients were available at the moment of defoliation, but the effects of defoliation on shoot N concentration and yield became negative, apparently due to the reduced ability of defoliated plants to compete for the pulse of inorganic nutrients added at the moment of defoliation.Our results show that the typical grass responses to defoliation—increased shoot N concentration and shoot N yield—are not necessarily mediated by soil organisms. We also found that these responses followed defoliation even when the ability of plants to utilize N from organic sources, such as plant litter, was diminished, because defoliated plants showed higher N-uptake efficiency per unit plant mass and allocated relatively more N to shoots than non-defoliated plants.  相似文献   

The effect of biochar with biogas digestate or mineral fertilizer on fertility,aggregation and organic carbon content of a sandy soil: Results of a temperate field experiment     

Isabel Greenberg  Michael Kaiser  Steven Polifka  Katja Wiedner  Bruno Glaser  Bernard Ludwig 《植物养料与土壤学杂志》2019,182(5):824-835

Substitution of mineral fertilizers with organic soil amendments is postulated to improve productivity‐relevant soil properties such as aggregation and organic matter (OM) content. However, there is a lack of studies analyzing the effects of biochar and biogas digestate versus mineral fertilizer on soil aggregation and OM dynamics under temperate field conditions. To address this research gap, a field experiment was sampled four years after establishment on a sandy Cambisol in Germany where mineral fertilizer or liquid biogas digestate was applied with or without 3 or 40 Mg biochar ha^?1 (produced at 650°C). Soil samples were analyzed for soil organic carbon (SOC) content, pH, cation exchange capacity, bulk density, water‐holding capacity, microbial biomass, aggregate size class distribution, and the SOC content associated with these size classes. 40 Mg biochar ha^?1 significantly increased SOC content in all fractions, especially free particulate OM and the 2–0.25 mm fraction. The yield of small macroaggregates (2–0.25 mm) was increased by biochar, but cation exchange capacity, water‐holding capacity, and pH were not consistently improved. Thus, high‐temperature biochar applied to a sandy soil under temperate conditions is primarily recommended to increase SOC content, which could contribute to climate change mitigation if this C remains sequestered over the long‐term. Fertilizer type did not significantly affect SOC content or other measured properties of the sandy Cambisol, suggesting that replacement of mineral fertilizer with digestate has a neutral effect on soil fertility. Co‐application of biochar with digestate provided no advantages for soil properties compared to co‐application with mineral fertilizer. Thus, independent utilization of these organic amendments is equally suitable.  相似文献   

The effects of nitrogen rate and the ratio of NO₃:NH₄ on Bemisia tabaci populations in hydroponic tomato crops     

Katja ?ani?  Gvozden Dumi?i?Marisa Škaljac  Smiljana Goreta BanBranimir Urli? 《Crop Protection》2011,30(2):228-233

Nitrogen fertilization is one of the factors that influences Bemisia tabaci (Gennadius) population density. The aim of this study was to determine the effects of three N application rates (75, 205 and 335 mg/l) and three ratios of NO₃⁻:NH₄⁺ ions (92:8, 75:25 and 55:45) in standard nutrient solution (205 mg/l N) on the population density of B. tabaci. The experiments were conducted on spring-summer hydroponic crops of tomato. The effect of plant stratum on the whitefly population was also determined. The aggregation of B. tabaci adults as well as their oviposition rate was higher at 205 and 335 mg/l N than on plants grown at 75 mg/l N. By the end of the experiment (60 d after infestation), the number of nymphs on plants at 205 mg/l N was higher than on plants at 75 mg/l N. The number of pupae was lowest on plants supplied with 75 mg/l N. An increase in NH₄⁺ percentage in standard nutrient solution (from 25% to 45% of the total N) reduced adult population density and oviposition rate. The density of nymphs and pupae, at 60 d after infestation, was lower on the tomato plants grown at 75:25 and 55:45 NO₃⁻:NH₄⁺ ratios compared to the 92:8 ratio. The 75:25 and 55:45 NO₃⁻:NH₄⁺ ratios resulted in a higher incidence of blossom-end rot of tomato fruit, with a lower incidence of disorder at 75:25 than at the 55:45 ratio. Plant stratum influenced adult whitefly distribution in two years of the study. Middle stratum leaves were more attractive to adults in both years. The results demonstrate the effects of N fertilization (N rate and the ratio of NO₃⁻:NH₄⁺) and plant stratum on B. tabaci population density.  相似文献