Mikhail Vainshtein

Link between the early calcium deposition in placenta and nanobacterial-like infection

The placenta is a vitally important organ in the regulation of embryonic development. That is why extensive calcium deposition [also named as pathological placental calcification (PPC)] could have serious negative consequences for the adequate growth of embryos. The nature and mechanism of PPC development has not been defined as yet. In the present investigation, we have tested the hypothesis that the molecular basis of PPC development consists of nanobacteria-induced calcification in infected female placenta. Electron microscopy findings support this hypothesis. The initial stage of micro-calcification may originate from the external surface of individual nanobacteria-like particles found mainly in placental extracellular matrix, where initial calcium deposition occurs as a needle surface deposition or as an amorphous-like surface precipitate. Further calcific propagation in placenta takes place in the newly formed macro-cavities, which are characterized by low electron density, possibly reflecting its liquid content around calcium deposition. The micro-cavities contain free nanobacterial-like particles, which may relate to atypical Gram-negative bacteria but not to apoptotic bodies by morphological characters and DNA/RNA distribution. We hypothesize that the increased placental calcification might be caused, at least in part, by nanobacterial infection.

Biosynthesis of arachidonic acid by micromycetes (review)

Arachidonic acid (ARA, 5,8,1l,14-cis-eicosatetraenoic acid) is widely used in medicine, pharmaceutics, cosmetics, dietary nutrition, agriculture, and other fields. Microbiological production of ARA is of increased interest since the natural sources (pig liver, adrenal glands, and egg-yolk) cannot satisfy its growing requirements. Mechanisms for ARA biosynthesis as well as the regulation of enzymes involved in this process are considered. Review summarizes literature data concerning individual stages of microbiological ARA production, methods for screening of active strains-producers, physiological regulation of ARA synthesis in micromycetes (the effect of growth phase, medium composition, pH, temperature, and aeration), and effective technologies of fermentation and the product recovery. Information on the whole biotechnological process from strain selection to the ARA yield improvement and purification of the end product is presented.

A New Type of Magnet-sensitive Inclusions in Cells of Photosynthetic Purple Bacteria

Summary The magnet-sensitive inclusions of a new type were discovered in cells of Rhodopseudomonas and Ectothiorhodospira species. The inclusions formed thread of beads along the main axis of cells and provided a movement of the biomass to the next pole of an applied static magnet. The electron microscopy of ultrathin sections showed a heterogeneous structure of the inclusions. The magnet-sensitive inclusions were the spherical particles containing an electron-transparent core surrounded with electron-dense matrix. The matrix was separated from cytoplasm with a homogeneous envelope of low electron density. X-ray microanalysis demonstrated that the matrix was enriched with iron.

Arachidonic acid as an elicitor of the plant defense response to phytopathogens

Review summarizes both literature and own experimental data on the application of arachidonic acid (AA, C20:4 omega-6) as an elicitor of the plant defense reactions to phytopathogens. The elicitation activity of AA was shown to depend considerably on its concentration. High AA concentrations (over 10-5 M) induce necrosis of plant tissues and accumulation of antimicrobial compounds (phytoalexins), whereas low AA concentrations (10-7–10-7 M) elicit systemic and prolonged resistance to the phytopathogen infections that is similar to immunization process. Biochemical mechanisms responsible for the elicitor activity of AA involve the whole complex of reactions including reconstruction of the cell ultrastructure, an increase in the amounts of certain enzymes and protective substances, a decrease in sterol content, redirection of isoprenoid biosynthesis from sterol derivatives toward sesquiterpenoid phytoalexins, and appearance of signal molecules, which are spread all over the plant tissues making them immunized. Field experiments revealed that the treatment of potato, tomato, sugar beet, and vine plants with low concentrations of pure AA or AA-containing preparations isolated from Phytophtora and Mortierella fungi increased plant resistance to diseases (late blight, common scrab, rhizoctonoise, cercosporose, powdery mildew, etc.) and thus enhanced the harvest yield. The application of AA-containing preparations is an alternative to the use of environmentally dangerous chemical fungicides. The processes of microbiological AA production from renewable inexpensive raw substrates are considered.

Application of organic acids for plant protection against phytopathogens

The basic tendency in the field of plant protection concerns with reducing the use of pesticides and their replacement by environmentally acceptable biological preparations. The most promising approach to plant protection is application of microbial metabolites. In the last years, bactericidal, fungicidal, and nematodocidal activities were revealed for citric, succinic, α-ketoglutaric, palmitoleic, and other organic acids. It was shown that application of carboxylic acids resulted in acceleration of plant development and the yield increase. Of special interest is the use of arachidonic acid in very low concentrations as an inductor (elicitor) of protective functions in plants. The bottleneck in practical applications of these simple, nontoxic, and moderately priced preparations is the absence of industrial production of the mentioned organic acids of required quality since even small contaminations of synthetic preparations decrease their quality and make them dangerous for ecology and toxic for plants, animals, and human. This review gives a general conception on the use of organic acids for plant protection against the most dangerous pathogens and pests, as well as focuses on microbiological processes for production of these microbial metabolites of high quality from available, inexpensive, and renewable substrates.

Formation of bacterial nanocells

Existence of nanobacteria received increasing attention both in environmental microbiology/geomicro-biology and in medical microbiology. In order to study a production of nanoforms by typical bacterial cells. Effects of different physical factors were investigated. Treatment of bacterial cultures with microwave radiation, or culturing in field of electric current resulted in formation a few types of nanocells. The number and type of nanoforms were determined with type and dose of the treatment. The produced nanoforms were: i) globules, ii) clusters of the globules--probably produced by liaison, iii) nanocells coated with membrane. The viability of the globules is an object opened for doubts. The nanocells discovered multiplication and growth on solidified nutrient media. The authors suggest that formation of nanocells is a common response of bacteria to stress-actions produced by different agents.

Synthesis of magneto-sensitive iron-containing nanoparticles by yeasts

Abstract Industrial production of magneto-sensitive nanoparticles, which can be used in the production of target drug delivery carriers, is a subject of interest for biotechnology and microbiology. Synthesis of these nanoparticles by microorganisms has been described only for bacterial species. At the same time, it is well known that yeasts can form various metal-containing nanoparticles used, for instance, in semiconductors, etc. This paper describes the first results of the biosynthesis of magneto-sensitive nanoparticles by yeasts. The organisms we used—Saccharomyces cerevisiae and Cryptococcus humicola—represented two different genera. Magneto-sensitive nanoparticles were synthesized at room temperature in bench-scale experiments. The study included transmission electron microscopy of the yeast cells and their energy dispersive spectrum analyses and revealed the presence of iron-containing nanoparticles. Both yeast cultures synthesized nanoparticles at high concentrations of dissolved iron. Electron microscopy showed that nanoparticles were associated mainly with the yeast cell wall. Formation of magneto-sensitive nanoparticles was studied under conditions of applied magnetic fields; a possible stimulating role of magnetic field is suggested. On the whole, the paper reports a novel approach to green biosynthesis of magneto-sensitive nanoparticles.

Functions of non-crystal magnetosomes in bacteria

Intracellular non-crystal magnetosomes are presented in prokaryotes of different taxonomic and physiological groups. Formation of the internal magnetosomes is provoked with some external agents. The situation permits to discuss functions of the magnetosomes as responses to surroundings. A few possible functions are discussed. Hypothesis on oriented motion of bacteria in geomagnetic field suits well data on the linear intracellular distribution of the magnetosomes in some species. An additional hypothesis is oriented attraction of iron-containing compounds to magnetic bacteria. Independently, magnetosomes have a function of the intracellular iron storage. In strong magnetic field, magnetosomes stimulated lysis of bacteria. Sometimes the bacterial lysis was accompanied with production of nanocells.

The effect of pH, aeration, and temperature on arachidonic acid synthesis by Mortierella alpina

The effects of pH, aeration, and temperature on the growth of fungal strain Mortierella alpina LPM-301 and the synthesis of lipids and arachidonic acid in glycerol-containing medium were studied. Arachidonic acid production in the stationary growth phase was found to depend considerably on the pH value; it reached the optimum at pH 6.0 and was irreversibly inhibited at a pH of 3.0. The pO2 values in a range from 10 to 50% showed no marked effect on mycelium growth or the synthesis of lipids and arachidonic acid. The temperature optimum for arachidonic acid production was 20–22°C. Under continuous cultivation, the amount of arachidonic acid reached 29.8% of lipids and 7.4% of biomass. The arachidonic acid yield from the glycerol consumed was 4.1% by mass and 8.8% by energy. It is suggested that arachidonic acid synthesis at an unfavorable pH and elevated temperatures was limited by the activity of Δ-12-desaturase and by the conversion of linoleic to arachidonic acid, respectively.

Bioleaching of Metals as Eco-friendly Technology

Bioleaching occupies an important place among the available mining technologies. Its significance is based on the possibility to use an expanding source of low-grade mineral materials, while another profit of this bio-hydrometallurgical process is to reduce the relevant costs for pollution abatement. This chapter presents a review of data from different research articles, patents, and some proprietary experiments. Different directions and possible future trends of this technology are discussed.