Peculiarities of the Seasonal Biology of Ectoparasites of the Genus <Emphasis Type="Italic">Spinturnix</Emphasis> von Heyden, 1826 (Mesostigmata: Gamasina: Spinturnicidae) in the Boreal Zone of the Palearctic Region

The most complete data on the peculiarities of seasonal biology of gamasid mites of the genus Spinturnix, which are ectoparasites of bats of the boreal zone of the Old World, are presented. Data on the dynamics of the sex and age structure of superpopulations of parasites throughout the year are presented; the infestation of various bat species is analyzed, and the factors affecting it are discussed. The main differences between the life cycles of the boreal and subboreal Spinturnicidae mites were revealed.     

The SPP1 connection

Abstract: The connector of the virulent Bacillus subtilis bacteriophage SPP1 (Styloviridae) is a structure localized at the phage head vertex which attaches the tail. It is formed by oligomerization of SPP1 gene product 6 (gp6; portal protein). The purified protein is found in solution essentially as a homo-tredecamer. Its assembly pattern resembles the turbine-like organization found for other portal proteins and has a defined handedness (Dube et al. (1993) EMBO J. 12, 1303–1309). A preliminary reconstruction of the structure shows that gp6 is composed of a lower ring connected by a narrow region to the upper area consisting of 13 lobes radiating from an inner ring. The assembly is organized around a central channel which spans its full height. A functional characterization of gp6 mutants showed that substitutions of defined amino acids by more basic residues lead to packaging of reduced amounts of DNA into the phage head (Tavares et al. (1992) J. Mol. Biol. 225, 81–92). Since SPP1 encapsidates its DNA by a headful mechanism, these mutations ( siz ) affect most probably a function on the headful sensor—signal transduction—headful cut system. Combination of siz alleles has severe effects in packaging. The resulting gp6 versions lead to the encapsidation of shorter DNA molecules at a lower efficiency than single siz mutants. Gene 6 is expressed late during SPP1 infection. Interestingly, the mass of portal protein inside the cell then increases continuously until lysis, reaching a level several fold higher than the amount required to accomplish its role as a structural component of the virion.     

Investigation of cell wall components in actinomycin D resistant Staphylococcus aureus]

Cell walls in 2 strains of Staphylococcus aureus 209P, i.e. actinomycin D susceptible and resistant ones were comparatively investigated. The resistant cells contained much more wall material per a unit of the biomass weight vs the susceptible strain cells, that conformed to thickening of the resistant cell walls detected by electron microscopy and a sharp increase of their electron density. Investigation of peptidoglycans and teichoic acids did not reveal any significant alterations in the structure of the wall components in the actinomycin D resistant cells. Only some increase of glucosamine in the peptidoglycan fraction of the resistant cells vs the susceptible ones was observed. It was shown that preparations of the resistant cell walls and peptidoglycan isolated from the resistant cells were able to bind somewhat lower quantities of actinomycin D vs the analogous preparations of the susceptible cells. The significant decrease of the antibiotic binding by live cells of the resistant strain probably slightly depended on the structure characteristics of the main wall components. The barrier properties of the walls in resistant staphylococci are most likely defined by the wall thickening and consolidation while adapting to actinomycin D.     

The nonlinear effect of the composite influence of red and blue light on <Emphasis Type="Italic">Escherichia coli</Emphasis> viability

A nonlinear dependence of E. coli cell inhibition was found during the simultaneous irradiation by the blue and red spectral regions at a power density of 100 mW/cm². This dependence can be explained by the cascade two-photon light absorption by DNA molecules with intermediate resonance at the cellular chromophores, which leads to excitation and subsequent DNA damage similar to the damage that is caused by exposure to UV quanta.     

The life cycle of the emerald ash borer Agrilus planipennis in European Russia and comparisons with its life cycles in Asia and North America

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New findings of gamasid mites belonging to families Laelapidae,Hirstionyssidae, and Haemogamasidae (Acari: Mesostigmata: Gamasina) on bats (Chiroptera)

Our own and previous data concerning the findings of parasitic gamasid mites (Mesostigmata: Gamasina) on bats (Chiroptera), which are not a principal host for them, are analyzed. The gamasid mites under study belong to the following families: Laelapidae Berlese, 1892; Hirstionyssidae Evans, Till, 1966; and Haemogamasidae Oudemans, 1926. In total, 27 species of parasites of the analyzed groups were found on bats. Among them, two species were described for bats for the first time. The medicinal value of this exchange is considered. Possible places where bats have contact with other mammals are discussed.     

The seasonal dynamics of diarrhetic shellfish poisoning toxins in the digestive gland of <Emphasis Type="Italic">Crenomytilus grayanus</Emphasis> (Dunker, 1853) analyzed by high-performance liquid chromatography with fluorometric detection

The seasonal dynamics of diarrhetic shellfish poisoning (DSP) toxins in the digestive gland of the mussel Crenomytilus grayanus (Dunker, 1853) from Peter the Great Bay in the Sea of Japan have been studied. Toxins in the form of 4-bromomethyl-7-methoxycoumarin derivatives have been analyzed using high-performance liquid chromatography (HPLC) with fluorometric detection. This method allows the determination of the quantitative and qualitative composition of individual toxins. All the C. grayanus samples contained DSP toxins, but their concentration varied substantially during the year. The highest concentration was recorded from the mussels collected in May; the lowest concentration was recorded in February. The toxins were represented predominantly by dinophysistoxin-2; in July-September and December, okadaic acid was detected. An assumption has been made about the relationship between the potential producers of DSP toxins in the waters of the Peter the Great Bay and the dynamics of these toxins in tissues of C. grayanus. The HPLC method, as an alternative to the enzyme-linked immunosorbent assay, was used to assess the quantitative and qualitative composition of DSP toxins in seafood for the first time in the Russian Federation. This method can be recommended for the routine monitoring of toxins conducted by the controlling organizations of the Russian Federal Service for Veterinary and Phytosanitary Surveillance.     

Earth Mover’s Distance (EMD): A True Metric for Comparing Biomarker Expression Levels in Cell Populations

Changes in the frequencies of cell subsets that (co)express characteristic biomarkers, or levels of the biomarkers on the subsets, are widely used as indices of drug response, disease prognosis, stem cell reconstitution, etc. However, although the currently available computational “gating” tools accurately reveal subset frequencies and marker expression levels, they fail to enable statistically reliable judgements as to whether these frequencies and expression levels differ significantly between/among subject groups. Here we introduce flow cytometry data analysis pipeline which includes the Earth Mover’s Distance (EMD) metric as solution to this problem. Well known as an informative quantitative measure of differences between distributions, we present three exemplary studies showing that EMD 1) reveals clinically-relevant shifts in two markers on blood basophils responding to an offending allergen; 2) shows that ablative tumor radiation induces significant changes in the murine colon cancer tumor microenvironment; and, 3) ranks immunological differences in mouse peritoneal cavity cells harvested from three genetically distinct mouse strains.     

Electron microscopy of beef heart mitochondrial F1-ATPase

The quaternary structure of isolated and membrane-bound F1-ATPase (submitochondrial particles) has been studied by electron microscopy. A model of the molecule has been proposed: six protein masses are arranged in two layers approximately at the vertices of a triangular antiprism. Computer averaging of the images showed that the frontal view of the molecule can be approximately characterized by mirror plane symmetry.