Antibody-mediated response of pigeons to Argas polonicus larval feeding and characterization of larval antigen

Circulating antibodies to larval Argas polonicus antigen detected in the blood of pigeons by means of ELISA reach their highest level 3-6 days post-tick attachment. During 6-8 days post infestation when most larvae detach from their host, there is an abrupt drop of the antibody level in blood followed by second peak at day 10-15. During the secondary and subsequent infestations the dynamics of the antibody production is analogous, but the maximum absorbance values found are higher with each following infestation. This is in direct correlation with the growth of immune resistance of hosts. The transfer of immunoglobulins of resistant pigeons produces in naive hosts a partial resistance in a statistically significant (P less than 0.01) reduction of the number of engorged larvae, in the shortening of larval feeding period and in the decrease of their mean weight after feeding. However this resistance was significantly (P less than 0.01) less expressed than in naturally resistant pigeons during secondary infestation. The protracted effect on the duration of premoulting period and the percentage of moulted larvae manifested in larvae after secondary infestation was not apparent in molecular weight of approximately 19, 21, 23, 27, 45 and 165 kilodaltons, were recognized by serum of resistant pigeons.     

Antigenic characterization of rat louse Polyplax spinulosa

Number and relative molecular weights of proteins in whole body homogenates of the louse, Polyplax spinulosa were determined using SDS-PAGE. 13 protein components from the total of 28 bands were defined as Con A binding glycoproteins. In immunoblotting sera of lice infested laboratory rats of BN strain specifically recognized 3 major protein components with r.m.w. of 77,000, 105,000 and 230,000 Da and from 6 to 8 minor protein components with r.m.w. of 31,000-180,000 Da.     

Technological properties and fire performance of medium density fibreboard (MDF) treated with selected polyphosphate-based fire retardants

ABSTRACT

The objective of the work was to evaluate the efficacy of two new polyphosphate-based fire retardants (FRs) and one commercial product named Siriono^® on the fire performance and physical–mechanical properties of medium density fibreboard (MDF) fabricated in the laboratory from Scots pine (Pinus sylvestris L.) wood. The fibres were treated with aqueous solutions of fire retardants, at 12% loading (dry salt on dry wood), and bonded with a melamine urea formaldehyde (MUF) adhesive. The physical and mechanical properties of panels were assessed using the European standards, whereas their fire performance was evaluated using an in-house method and the Cone calorimeter. In overall, the chemicals added enhanced the fire and smoke properties of the panels to varying degrees. Critical FR parameters such as peak heat release rate (peak HRR), total heat release (THR) and total smoke production (TSP) were significantly improved in the FR-treated panels, as exhibited in cone calorimeter tests. However, the internal bond strength of treated panels largely decreased by the addition of fire retardants, while thickness swell and water absorption negatively affected to a significant extent. In contrast, the formaldehyde release of the panels was considerably decreased at the E1 class level, with the incorporation of the polyphosphate-based additives.     

Peptidases of Trichobilharzia regenti (Schistosomatidae) and its molluscan host Radix peregra S. Lat. (Lymnaeidae): construction and screening of cDNA library from intramolluscan stages of the parasite

Trichobilharzia regenti is a neurotropic bird schistosome,causing cercarial dermatitis in humans. In this study, ZAP cDNA expression library from Radix peregra s. lat. hepatopancreases containing intramolluscan stages of T. regenti was constructed and screened using PCR with specific and degenerate primers, designed according to previously described serine and cysteine peptidases of other parasite species. Full-length sequences of cathepsins B1 and L, and two serine peptidases, named RpSP1 and RpSP2, were obtained.The protein-protein BLAST analysis and parallel control reactions with template from hepatopancreases of T. regenti non-infected snails revealed that only cathepsin B1 was of parasite origin. The remaining sequences were derived from the snail intermediate host, which implies that the initial source of parasite mRNA was contaminated by snail tissue.Regardless of this contamination, the cDNA library remains an excellent molecular tool for detection and identification of bioactive molecules in T. regenti cercariae.     

Isolation and characterization of an immunogen from the louse Polyplax spinulosa

The reaction of Polyplax spinulosa protein components with antigen-specific rat antisera and with five plant lectins is described. In immunoblotting, the antisera from rats infested with the louse P. spinulosa specifically recognized from 7 to 11 antigenic components of louse whole-body homogenates. Affinoblotting analysis with lectins showed that 10 of these components were glycoproteins with different types of glycan structure. Only one immunogenic antigen was isolated using immunoaffinity chromatography with the gammaglobulin fraction of an antigen-specific antiserum as immunospecific ligand. Further electrophoretic and immunochemical analyses revealed that it was a glycoprotein with relative molecular weight (RMW) 31 kDa and with high mannose type of oligosaccharide.     

Babesia microti (Piroplasmida: Babesiidae) in nymphal Ixodes ricinus (Acari: Ixodidae) in the Czech Republic

A total of 350 nymphs of the common tick Ixodes ricinus (Linnaeus, 1758) were collected in an endemic focus of Lyme borreliosis (South Moravia, Czech Republic) and examined for the presence of the protozoan Babesia microti (Fran?a, 1909) by polymerase chain reaction (PCR), using primers specific for the B. microti gene encoding small subunit rRNA. The assay revealed five positive pools (out of 70 pools examined); the corresponding prevalence rate was about 1.5%. Sequence analysis of the PCR products confirmed their 100% homology with that of B. microti. The study represents the first evidence of B. microti in ixodid ticks in the Czech Republic.     

Rapid serological diagnosis of tick-borne encephalitis by means of enzyme immunoassay

A system of IgM-capture EIA made up from Czechoslovak immunopreparations (SEVAC) was developed for a rapid serological diagnosis of tick-borne encephalitis (TBE). The method was tested on clinical material. The total IgM antibody titres were detected using pig antiserum and the selection of specific IgM antibodies was made with TBE antigen with following indirect way of detection. The antibody analysis made by means of this method is sensitive and fully conforms to the clinical picture of the disease.     

Lyme borreliosis: insights into tick-/host-borrelia relations

Lyme borreliosis (LB) is a serious infectious disease of humans and some domestic animals in temperate regions of the Northern Hemisphere. It is caused by certain spirochetes in the Borrelia burgdorferi sensu lato (s.l.) species complex. The complex consists of 11 species (genospecies). Borrelia burgdorferi sensu stricto (s.s.), Borrelia garinii and Borrelia afzelii are the major agents of human disease. Borrelia burgdorferi s.l. species are transmitted mainly by ticks belonging to the Ixodes ricinus species complex plus a few additional species not currently assigned to the complex. B. burgdorferi infections may produce an acute or chronic disease with a wide array of clinical symptoms such as erythema migrans (EM), carditis, arthritis, neuroborreliosis, and acrodermatitis chronica atrophicans (ACA). Differences in LB spirochetes 'genospecies' and strains/isolates determine the occurrence and severity of this multi-system disease. Accurate and reliable identification of the LB spirochetes in ticks as well as knowledge of their prevalence are essential for prevention against the disease and development of an effective vaccine. An overview of the knowledge of molecular factors with emphasis on potential protein-carbohydrate interactions in the tick-borrelia system is the main focus of this review.     

Effects of Endo- and Ectomycorrhizal Fungi on Physiological Parameters and Heavy Metals Accumulation of Two Species from the Family Salicaceae

There is increasing interest in poplars and willows due to their biomass production and phytoremediation potential. They host two major types of mycorrhizal fungi that can substantially modulate the physiology of their hosts. In this study, the effects of endo- and ectomycorrhizal fungi on growth, physiological parameters, and heavy metals accumulation were studied in a pot experiment using Salix alba L. and Populus nigra L. The mycorrhizal fungi were inoculated separately and in combination to a soil substrate polluted by a mixture of heavy metals (mainly Cd, Pb, and Zn). Tree species differed in their mycorrhizal affinities, with poplar being colonized predominantly by Glomus intraradices and willow by Hebeloma mesophaeum. H. mesophaeum increased willow height and biomass, while G. intraradices decreased poplar height. The photosynthetic rate remained unchanged, and only minor changes were observed in the relative composition of photosynthetic pigments. Poplar photosynthetic rates and levels of photosynthetic pigments declined, while the epicuticular waxes in leaves increased toward the end of the experiment, irrespective of the inoculation. H. mesophaeum strongly reduced the accumulation of Cd and Fe in willow and poplar shoots, respectively. Our results support the use of selected mycorrhizal strains to tune phytoremediation outcomes in their plant hosts.