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RECOMBINANT SINGLE CHAIN ANTIBODIES AS AN INSTRUMENT TO SEARCH PROTEINS INVOLVED IN THE INTERACTION OF MICROSPORIDIA AND OTHER INTRACELLULAR PARASITES WITH AN INFECTED HOST CELL
стр.5-13
Tsarev A.A., Senderskiy I.V., Timofeev S.A., Zhuravlyov V.S., Dolgikh V.V.
Obligate parasitism of microsporidia - close to fungi protists causing widespread diseases of animals and immunodeficient patients, significantly complicates studies of their relationships with an infected host cell. Since microsporidia cannot be cultivated outside the host cell, genetic manipulations with them are extremely difficult. At the same time, long adaptation of microsporidia to the intracellular lifestyle, drastic minimization of their metabolic machinery, acquisition of unique transporters to exploit a host cell make these parasites a very valuable object for such study and require a search for new methods of investigation. Here, we describe our experiment on the construction of the library of recombinant single chain antibodies (scFv fragments) against proteins of fat bodies of locusts Locusta migratoria infected by the microsporidia Paranosema (Antonospora) locustae. The representativeness of this library was about 108 E. coli transformants carrying different combinations of variable fragments of heavy and light chains of immunized mice immunoglobulins. The first results of the selection of scFv fragments from the constructed library by phage display technology demonstrated that this approach may be effective to search proteins involved in the interaction of microsporidia and other intracellular parasites with an infected host cell. Cloning of selected genes into the expression vector, transformation of E. coli and screening two hundred bacterial colonies revealed scFv fragments against several such candidate proteins to begin their study. Further experiments with the library should discover new variants of recombinant antibodies interacting with the parasite and host proteins.
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RARE CASE OF MICROSPORIDIA CO-INFECTION IN THE GRASSHOPPER DICHROPLUS ELONGATUS (ORTHOPTERA: ACRIDIDAE: MELANOPLINAE)
стр.14-18
Lange C.E., Cigliano M.M.
Two Microsporidia species are known to parasitize Dichroplus elongatus in the Pampas region of Argentina, allochthonous Paranosema locustae, a generalist pathogen of the adipose tissue of grasshoppers with efficient horizontal and vertical transmission routes, and autochthonous Liebermannia dichropluse, a D. elongatus-specific pathogen of the Malpighian tubules with effective transovarial transmission but unknown horizontal transfer. Long-term monitoring of grasshopper communities for detection of microsporidioses revealed that it is not often that these two pathogens co-exist in populations of D. elongatus, even in different individuals. We report the unusual detection for the first time of a co-infection by P. locustae and L. dichroplusae in D. elongatus at a site in the southern Pampas. Given the own traits that characterize both pathogens we presume that the most likely scenario for the occurrence of the observed mixed infection is that the affected D. elongatus individual was already infected by L. dichroplusae when it contracted infection by P. locustae. Unfortunately, our attempts to induce infections with L. dichroplusae in the laboratory through experimental inoculations have not produced positive results, preventing efforts towards testing our presumption through laboratory bioassays. However, Microsporidia natural mixed infections appear to be so rare that we believe this case is worth reporting.
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NEW INSIGHTS INTO NO GENERATION AND AOX1 UPREGULATION IN CHLAMYDOMONAS
стр.19-25
Ostroukhova M., Ermilova E.
Emerging evidence indicates a close connection between components mitochondrial electron transport chain (mETC), nitric oxide (NO) and alternative oxidase (AOX) activity in plants. In unicellular algae, AOXs are monomeric fungi-type proteins. We previously showed that in Chlamydomonas reinhardtii stress-induced AOX1 expression was significantly higher under dark conditions. Here we found that in dark aerobic Chlamydomonas cells, complex III of mETC produces NO from nitrite, and monomeric AOX1 appeared to be involved in reducing this activity. Moreover, in dark-incubated cells, NO generation is not mediated by nitrate reductase and nitric oxide-forming nitrite reductase complex. Under conditions limiting the flow of electrons through complex III, the expression of AOX1 but not the AOX2 expression is dependent on changes in NO levels. Taken together, the data indicate that in the absence of light, NO generated by mETC, is a key molecule controlling AOX1 levels in Chlamydomonas aerobic cells.
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LIGHT-MICROSCOPIC MORPHOLOGY AND ULTRASTRUCTURE OF POLYCHAOS ANNULATUM (PENARD, 1902) SMIRNOV ET GOODKOV, 1998 (AMOEBOZOA, TUBULINEA, EUAMOEBIDA), RE-ISOLATED FROM THE SURROUNDINGS OF ST. PETERSBURG (RUSSIA)
стр.26-35
Kamyshatskaya O., Mesentsev Ye., Chistyakova L., Smirnov A.
We isolated the species Polychaos annulatum (Penard, 1902) Smirnov et Goodkov, 1998 from a freshwater habitat in the surrounding of Saint-Petersburg. The previous re-isolation of this species took place in 1998; at that time the studies of its light-microscopic morphology were limited with the phase contrast optics, and the electron-microscopic data were obtained using the traditional glutaraldehyde fixation, preceded with prefixation and followed by postfixation with osmium tetroxide. In the present paper, we provide modern DIC images of P. annulatum. Using the fixation protocol that includes a mixture of the glutaraldehyde and paraformaldehyde we were able to obtain better fixation quality for this species. We provide some novel details of its locomotive morphology, nuclear morphology, and ultrastructure. The present finding evidence that P. annulatum is a widely distributed species that could be isolated from a variety of freshwater habitats.
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ON THE IMPORTANCE OF ATTENTIVE READING OF RESEARCH ARTICLES: THE CASE STUDY OF FRONTONIA (PENICULIA, OLIGOHYMENOPHORA, CILIOPHORA) SPECIES DESCRIPTIONS AND REDESCRIPTIONS
стр.36-41
A commonly encountered problem of ignoring or inattentive reading of scientific articles by some protistologists of the past and present has been revealed using the case study of taxonomy of the ciliate genus Frontonia. The comparison between materials from literature and own investigations allowed the author to conclude that F. vernalis Ehrenberg, 1833 cannot to be a valid species and assume that it is rather a cluster of closely related freshwater ciliates with one contractile vacuole and a stable ability to accommodate green algae as the cytoplasmic symbionts. “F. vernalis”, as described by Bullington (1939), was shown to have little in common with the original description by Ehrenberg and most likely is a brackishwater ciliate similar to F. fusca. F. oculiaris described by the same author (Bullington, 1939) is obviously F. fusca, and the name “F. oculiaris” should be considered as a younger synonym of the latter. Thus, redescription of F. oculiaris (Pan et al., 2013b) should be treated just as a morphological study of the local Chinese population of F. fusca. The redescription of F. canadensis from brackish waters by the same authors can be considered as a description of a new species that has little in common with the original description of this freshwater ciliate (Roque and Puytorac, 1972). Recent phylogenetical reconstructions indicate the necessity to split Frontonia into several genera.
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