Molecular detection and characterization of Anaplasma phagocytophilum strains

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.     

Studies on sperm of diploid and triploid tench, Tinca tinca (L.)

The tench Tinca tinca is an interesting fish from the viewpoint of polyploidy and related atypical reproduction aspects. Triploid tench were produced artificially. Studies of spermiation as well as of sperm motility and structure were performed on several triploid and diploid males simultaneously with individual experimental crosses with diploid females to define their reproductive capacities. The testes of triploids visually looked less developed in the most of cases with lower sperm production (0.05 cm³ sperm per male), GSI and weight of testes compared to diploids (0.58 cm³ sperm per male). Analysis of variance showed significant influence of ploidy level on the percentage of motile spermatozoa. Triploidy did not change percentage of live spermatozoa and velocity of spermatozoa at the first time of sperm movement. The study of sperm structure by scanning electron microscopy revealed that most sperm cells were of normal structure with some anomalies. Sperm heads of triploid and diploid males were mostly round-shaped, 1.86±0.2 and 1.6±0.18 μm in diameter. The midpiece of triploid spermatozoa was slightly narrower than that of diploid ones with typical cylindrical shape. Flow cytometry revealed sperm cells of triploids to be largely aneuploid (1.47 n) with high mosaic DNA, oscillating from haploid DNA content (1.0 n) to diploid DNA content (1.9 n). Experimental crosses between triploid males and diploid females revealed that these males were capable to stimulate effective development with relatively high level of fertilization and hatching rates from 0 to 70%. In conclusion, triploidization does not seem to guarantee sterility of tench.     

Transmission biology of Raspberry latent virus, the first aphid-borne reovirus

Raspberry latent virus (RpLV) is a newly characterized reovirus found in commercial raspberry fields in the Pacific Northwest (PNW). Thus far, all members of the plant reoviruses are transmitted in a replicative, persistent manner by several species of leafhoppers or planthoppers. After several failed attempts to transmit RpLV using leafhoppers, the large raspberry aphid, commonly found in the PNW, was tested as a vector of the virus. The virus was transmitted to new, healthy raspberry plants when inoculated with groups of at least 50 viruliferous aphids, suggesting that aphids are vectors of RpLV, albeit inefficient ones. Using absolute and relative quantification methods, it was shown that the virus titer in aphids continued to increase after the acquisition period even when aphids were serially transferred onto fresh, healthy plants on a daily basis. Transmission experiments determined that RpLV has a 6-day latent period in the aphid before it becomes transmissible; however, it was not transmitted transovarially to the next generation. To our knowledge, this is the first report of a plant reovirus transmitted by an aphid. Phylogenetic analyses showed that RpLV is related most closely to but distinct from Rice ragged stunt virus (RRSV), the type member of the genus Oryzavirus. Moreover, the conserved nucleotide termini of the genomic segments of RpLV did not match those of RRSV or other plant reoviruses, allowing us to suggest that RpLV is probably the type member of a new genus in the Reoviridae comprising aphid-transmitted reoviruses.     

Hormonal profile and morphological changes in pig ovaries after intraovarian infusions of Escherichia coli endotoxin

The purpose of this study was to estimate morphological changes in the ovary and size of the production of steroid hormones during the luteal phase of the estrous cycle in pigs after intraovarian infusions of Escherichia coli endotoxin. Polish Large White gilts (n = 15) of similar age (7-8 months) and body weight (90-110 kg) with two controlled subsequent estrous cycles were used. The animals were randomly divided into two groups: control (n = 9, the 10th day of the estrous cycle,) and treated with Escherichia coli endotoxin (n = 6, the same day of the estrous cycle). The gilts were infused with Escherichia coli endotoxin at a dose of 1 mg three times a day during six consecutive days, from the 14th to the 19th day of the estrous cycle. Plasma concentrations of progesterone (P4), androstenedione (A4), testosterone (T), estrone (E1) and estradiol-17 beta (E2) were determined by radioimmunoassay method. Infusions of Escherichia coli endotoxin resulted in a significant (p < 0.001) decrease in the production of P4, A4, T, E1 and E2 in the luteal phase as compared with the levels found in the control animals. Plasma level of P4, A4 and T was decreased by 84.6%, 86.0% and 73.0%, respectively. Plasma concentrations of E1 and E2 in some cases exceeded 5 pg/ml, nevertheless in the majority of the samples they were under sensitivity of the method. Escherichia coli endotoxin infusions resulted in a considerable decrease in the size of the ovaries, and morphological changes characteristic for acute and chronic inflammation were observed.     

The utility of the ‘Arable Weeds and Management in Europe’ database: Challenges and opportunities of combining weed survey data at a European scale

Over the last 30 years, many studies have surveyed weed vegetation on arable land. The ‘Arable Weeds and Management in Europe’ (AWME) database is a collection of 36 of these surveys and the associated management data. Here, we review the challenges associated with combining disparate datasets and explore some of the opportunities for future research that present themselves thanks to the AWME database. We present three case studies repeating previously published national scale analyses with data from a larger spatial extent. The case studies, originally done in France, Germany and the UK, explore various aspects of weed ecology (community composition, management and environmental effects and within-field distributions) and use a range of statistical techniques (canonical correspondence analysis, redundancy analysis and generalised linear mixed models) to demonstrate the utility and versatility of the AWME database. We demonstrate that (i) the standardisation of abundance data to a common measure, before the analysis of the combined dataset, has little impact on the outcome of the analyses, (ii) the increased extent of environmental or management gradients allows for greater confidence in conclusions and (iii) the main conclusions of analyses done at different spatial scales remain consistent. These case studies demonstrate the utility of a Europe-wide weed survey database, for clarifying or extending results obtained from studies at smaller scales. This Europe-wide data collection offers many more opportunities for analysis that could not be addressed in smaller datasets; including questions about the effects of climate change, macro-ecological and biogeographical issues related to weed diversity as well as the dominance or rarity of specific weeds in Europe.     

Electron microscopy and molecular identification of phytoplasmas associated with strawberry green petals in the Czech Republic

The presence of phytoplasma inFragaria ananassa x Duch cv Senga Sengana showing strawberry green petals symptoms was observed by electron microscopy of phloem tissue. No phytoplasmas were found in asymptomatic strawberry plants used as controls. Nucleic acids extracted from these plants were used in nested-PCR assays with primers amplifying 16S rRNA sequences specifie for phytoplasmas. Bands of 1.2 kb were obtained and the subsequent nested-PCR with specific primers and RFLP analyses allowed to classify the detected phytoplasmas in the aster yellows group (16SrI). They belonged to the subgroup I-C of which type strain is clover phyllody phytoplasma.     

Changes in soil properties and site productivity caused by red alder

Red alder (Alnus rubra Bong.) is well recognized as an effective host plant for the symbiotic fixation of N. While this fixation process leads to the rapid accumulation of N within the ecosystem, it also enhances nutrient accumulation in biomass and soil organic matter and increases nitrification and cation leaching. We hypothesized that changes in soil properties resulting from these processes would decrease site productivity for second rotation red alder. Adjacent stands of 55 yr old alder and Douglas fir (Pseudotsuga menziesii (Mirb.] Franco) were studied at the Thompson Research Center on the Cedar River Watershed in western Washington, USA.The presence of red alder caused the following soil changes: decreased soil solution pH, increased CEC, increased exchangeable acidity accompanied by a decreased soil pH and base saturation. This decreased soil and soil solution pH resulted in increased A1 concentration in the soil solution and on exchange sites as well as decreased P availability. To determine the effect of these changes on the productivity of the 2nd rotation alder forest, a species conversion experiment was initiated 5 yr ago. Results from this conversion study clearly indicated that the first rotation red alder forest has caused a relative decrease in the productivity of the second rotation red alder plantation. Compared to the growth of red alder on the former Douglas fir site, the second rotation red alder on the former red alder site exhibited 339 less height growth and 759, less aboveground biomass accumulation after 5 yr. Future research will focus on identifying those factors causing this lower productivity including P availability, soil acidity and Al toxicity, cation availability, and competition with other vegetation.     

Effect of heavy metals on growth population of a fecal coliform bacterium Escherichia coli in aquatic environment

The data on the effects of the concentrations (0.5, l, 2, 5 mg L^?1) of the heavy metals, Hg, As, Pb, Cu, Cd, and Cr on changes in growth population of a fecal coliform bacterium Escherichia coli (in term of number of E. coli per 100 mL water) showed a gradual decline in growth population of the fecal coliform bacterium with the increase of exposure time, as well as concentrations of the metals over control data. The effects were markedly recorded with the treatment of 5 mg L^?1. In general, the harmful effects of the metals on growth population of E. coli were found by the treatments in the order: Cd>Ph>Cu>As>Hg>Cr.     

Exudation of allelopathic substances in buckwheat (Fagopyrum esculentum Moench)

Root exudates of the common buckwheat, especially phenolic compounds, were studied. Their contents, both in the soil during the growing season and in agar medium during germination, were determined by HPLC and GC-MS. The allelopathic activity of the soil from a buckwheat stand was evaluated, as well. Palmitic acid, squalene, epicatechin, vitexin, a gallic acid derivative, and a quercetin derivative were the main compounds of the agar medium. In the soil, palmitic acid methyl ester, vanillic acid, rutin, a gallic acid derivative, and a 4-hydroxyacetophenone derivative were identified. The effects of vitexin, squalene, epicatechin, 4-hydroxyacetophenone, and vanillic and gallic acids were tested on eight plant species. Inhibitive effects were observed in the cases of 4-hydroxyacetophenone and vanillic and gallic acids. Comparisons of the identified compounds and inhibitive effects of soil extracts indicated that palmitic acid and the gallic acid derivative probably have an important function in the allelopathic root response of buckwheat.