排序方式： 共有4条查询结果，搜索用时 15 毫秒
1
1.
Paulauskas A Radzijevskaja J Rosef O 《Comparative immunology, microbiology and infectious diseases》2012,35(2):187-195
The zoonotic rickettsial pathogen Anaplasma phagocytophilum has a broad geographic distribution and a high degree of biological and clinical diversity. To investigate the genetic diversity of A. phagocytophilum strains in the Baltic region and Norway, three species of Ixodidae ticks were examined for A. phagocytophilum infection, and two genes of the pathogen genome were analyzed. Analysis of partial 16S rRNA and partial major surface protein (msp4) gene sequences was accomplished through nested PCR and sequence analysis. Strains identified in this study were compared with those originating from other European countries and the United States. Seven 16S rRNA gene variants and fifteen msp4 gene variants of A. phagocytophilum were detected. Nine sequences had unique nucleotide polymorphisms and therefore differed from other A. phagocytophilum sequences previously submitted to GenBank. The present study represents the first molecular characterization of A. phagocytophum strains circulating in Lithuania and describes the strains detected in Ixodes persulcatus ticks in Latvia and Estonia. This is also the first report describing A. phagocytophilum strains isolated from Dermacentor reticulatus ticks. 相似文献
2.
Kristina Raitelaityt&#x; Svetlana Markovskaja Algimantas Paulauskas Tom Hsiang Tomasz Oszako 《Forest Pathology》2020,50(2)
The presence of quarantine pathogen Lecanosticta acicola, the causal agent of brown spot needle blight, was confirmed using molecular methods for the first time in northern part of Poland on the coastal area adjacent to the Baltic Sea. This area includes sandy beaches, where Pinus mugo and P. sylvestris were planted. Symptomatic needles were collected in 2017 from 20 P. mugo trees growing in one stand in Ustka. Typical symptoms of brown spot needle blight infection, including dead needle tips and central zones with yellow or reddish brown, circular spots in green tissue, were observed on all samples. Only, the asexual stage of L. acicola was obtained during this work. The pathogen species identity was confirmed using classical morphological methods (microscopic examination of the infected needles), real‐time and species‐specific priming (SSPP) PCR, and ITS sequencing. Analysis of mating‐type (MAT) genes showed the presence of both mating types in northern Poland. 相似文献
3.
Dalia-Marija Brazauskiene Valdas Paulauskas Nomeda Sabiene 《Journal of Soils and Sediments》2008,8(3):184-192
Background, aim, and scope Heavy metal (HM) mobility in soil depends on the HM species in it. Therefore, knowledge of the HM speciation in soil allows
the prediction of HM impact on the environment. HM speciation in soil depends on the metal chemical origin, soil texture,
and other factors such as the origin and level of soil contamination. Recently, the problem of organic waste utilization is
of great importance as the amount of this recyclable material is continually increasing. One of the possible ways of recycling
is the use of processed organic wastes for agricultural needs. In this research, aerobically composted sewage sludge was used,
the utilization of which is of essential importance. But one of the most serious restrictions is HM transfer from such material
to the soil. Therefore, a prediction of HM mobility in soil and its migration in the environment is an important issue when
using sewage sludge compost (SSC) in agriculture. Zn, Cu, and Pb speciation was performed according to the modified methodology
of Tessier et al. (Anal Chem 51:844–851, 1979) in two different (sandy and clay) soils with background HM amounts and in soil samples amended with aerobically digested
SSC to find out the predominant species of the investigated HM and to predict their potential availability.
Materials and methods The modified method of sequential extraction initially proposed by Tessier et al. (Anal Chem 51:844–851, 1979) is designed for HM speciation into five species where HM mobility decreases in the order: F1—exchangeable HM (extracted with 1 M MgCl2 at an initial pH of 7 and room temperature), F2—carbonate-bound HM (extracted with 1 M CH3COONa buffered to pH 5 at room temperature), F3—Fe/Mn oxide-bound HM (extracted with 0.04 M NH2OH·HCl at an initial pH of 2 at 96°C), F4—organic matter-complexed or sulfide-bound HM (extracted with 0.02 M HNO3 and 30% (v/v) H2O2 at a ratio of 1:1 and an initial pH of 2 at 85°C), and F5—the residual HM (digested with HNO3, HF, and HCl mixture). After digestion, HM amounts in solution were determined by atomic absorption spectrometry (AAS ‘Hitachi’).
Mixtures of uncontaminated soils of different textures (clay and sandy) with SSC in ratios 20:1, 10:1, and 5:1 were used to
simulate the land application with SSC. During a period of 7 weeks, changes in Zn, Cu, and Pb content within species were
investigated and compared weekly in soil–SSC mixtures with their speciation in pure soil and in the SSC.
Results Results in the SSC showed that more HM were found as mobile species compared to the soils, and in sandy soil, more were found
in the mobile species than in clay soil. But the HM speciation strongly depended on the metal chemical origin. According to
the potential availability, HM ranked in the following order: Zn>Pb>Cu. Zinc generally occurred in the mobile species (F1
and F3), especially in sandy soils amended with SSC, and changes of the Zn speciation were insignificant at the end of the
experiment. Pb transfer to insoluble compounds (F5) was evident in the SSC–soil mixtures. This confirms that Pb is extremely
immobile in the soil. However, the observed increase of Pb amounts in the mobile species (F1 and F2) during the course of
experiment shows a critical trend of Pb mobilization under anthropogenic influence. Copper in the soil–SSC mixtures had a
trend to form compounds of low mobility, such as organic complexes and sulfides (F4) and nonsoluble compounds (residual fraction
F5). Initially, the amounts of mobile Cu species (F1 and F2) increased in the soils amended with SSC, probably due to the
influence of SSC of anthropogenic origin with lower pH and high organic matter content, but Cu mobility decreased nearly to
the initial level again after 3–4 weeks. Hence, the soil has a great specific adsorption capacity to immobilize Cu of anthropogenic
origin.
Discussion Zn mobility and environmental impact was greater than that seen for Cu and Pb, while mobility of both Cu and Pb was similar,
but variable depending on soil texture and contamination level. The effect on the shift of HM mobility and potential availability
was greater in sandy SSC-amended soils than in clay soils and increased with an increasing amount of SSC.
Conclusions Usage of SSC for land fertilization should be strictly regulated, especially regarding Pb amounts.
Recommendations and perspectives The influence of SSC on Cu and Zn mobility and potential availability was more significant only in the case of sandy soil
with a higher SSC ratio. Nevertheless, this waste product of anthropogenic origin increased Pb mobility in all cases in spite
of only moderate Pb mobility in SSC itself. Therefore, aerobic processing of sewage sludge must be strictly regulated, especially
regarding Pb amounts, and SSC ratios must be in control regarding HM amounts when using it for on-land application. 相似文献
4.
Background
Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum have been considered as pathogens in animals and humans. The role of wild cervids in the epidemiology is not clear. We analyzed questing Ixodes ricinus ticks collected in spring for these pathogens from sites with high (Fjelløyvær and Strøm) and low density (Tjore, Hinnebu and Jomfruland) of wild cervids to study the spread of the pathogens in questing ticks.Methods
For detection of Anaplasma phagocytophilum a 77-bp fragment in the msp2 gene was used. Detection of Borrelia burgdorferi sensu lato was performed using the FL6 and FL7 primers according to sequences of conserved regions of the fla gene. The OspA gene located on the linear 49-kb plasmid was used as target in multiplex PCR for genotyping. Genospecies-specific primers were used in the PCR for Borrelia burgdorferi sensu stricto, B. afzelii and B. garinii.Results
Infection rates with Borrelia spp. were significantly lower at Fjelløyvær and Strøm compared to Tjore and Hinnebu; Fjelløyvær vs. Tjore (χ2 = 20.27, p < 0.0001); Fjelløyvær vs. Hinnebu (χ2 = 24.04, p < 0.0001); Strøm vs. Tjore (χ2 = 11.47, p = 0.0007) and Strøm vs. Hinnebu (χ2 = 16.63, p < 0.0001). The Borrelia genospecies were dominated by. B. afzelii (82%) followed by B. garinii (9.7%) and B. burgdorferi sensu stricto (6.9%). B. burgdorferi s.s. was only found on the island of Jomfruland. The infection rate of Anaplasma phagocytophilum showed the following figures; Fjelløyvær vs Hinnebu (χ2 = 16.27, p = 0.0001); Strøm vs. Tjore (χ2 = 13.16, p = 0.0003); Strøm vs. Hinnebu (χ2 = 34.71, p < 0.0001); Fjelløyvær vs. Tjore (χ2 = 3.19, p = 0.0742) and Fjelløyvær vs. Støm (χ2 = 5.06, p = 0.0245). Wild cervids may serve as a reservoir for A. phagocytophilum. Jomfruland, with no wild cervids but high levels of migrating birds and rodents, harboured both B. burgdorferi s.l. and A. phagocytophilum in questing I. ricinus ticks. Birds and rodents may play an important role in maintaining the pathogens on Jomfruland.Conclusion
The high abundance of roe deer and red deer on the Norwegian islands of Fjelløyvær and Strøm may reduce the infection rate of Borrelia burgdorferi sensu lato in host seeking Ixodes ricinus, in contrast to mainland sites at Hinnebu and Tjore with moderate abundance of wild cervids. The infection rate of Anaplasma phagocytophilum showed the opposite result with a high prevalence in questing ticks in localities with a high density of wild cervids compared to localities with lower density. 相似文献
1