Quantitative analysis of microtubule transport in growing nerve processes

In neurons, tubulin is synthesized primarily in the cell body, whereas the molecular machinery for neurite extension and elaboration of microtubule (MT) array is localized to the growth cone region. This unique functional and biochemical compartmentalization of neuronal cells requires transport mechanisms for the delivery of newly synthesized tubulin and other cytoplasmic components from the cell body to the growing axon. According to the polymer transport model, tubulin is transported along the axon as a polymer. Because the majority of axonal MTs are stationary at any given moment, it has been assumed that only a small fraction of MTs translocates along the axon by saltatory movement reminiscent of the fast axonal transport. Such intermittent "stop and go" MT transport has been difficult to detect or to exclude by using direct video microscopy methods. In this study, we measured the translocation of MT plus ends in the axonal shaft by expressing GFP-EB1 in Xenopus embryo neurons in culture. Formal quantitative analysis of MT assembly/disassembly indicated that none of the MTs in the axonal shaft were rapidly transported. Our results suggest that transport of axonal MTs is not required for delivery of newly synthesized tubulin to the growing nerve processes.     

Neuropeptide delivery to synapses by long-range vesicle circulation and sporadic capture

Neurotransmission requires anterograde axonal transport of dense core vesicles (DCVs) containing neuropeptides and active zone components from the soma to nerve terminals. However, it is puzzling how one-way traffic could uniformly supply sequential release sites called en passant boutons. Here, Drosophila neuropeptide-containing DCVs are tracked in vivo for minutes with a new method called simultaneous photobleaching and imaging (SPAIM). Surprisingly, anterograde DCVs typically bypass proximal boutons to accumulate initially in the most distal bouton. Then, excess distal DCVs undergo dynactin-dependent retrograde transport back through proximal boutons into the axon. Just before re-entering the soma, DCVs again reverse for another round of anterograde axonal transport. While circulating over long distances, both anterograde and retrograde DCVs are captured sporadically in en passant boutons. Therefore, vesicle circulation, which includes long-range retrograde transport and inefficient bidirectional capture, overcomes the limitations of one-way anterograde transport to uniformly supply release sites with DCVs.     

Gangliosides of sea urchin embryos. Their localization and participation in early development

The influence of antibodies to gangliosides of sea urchin Strongylocentrotus intermedius eggs on early embryos of this species was studied. gamma-Globulins were isolated from rabbit anti-ganglioside serum by micropreparative electrophoresis. These gamma-globulins produced anomalies in the development of embryos permeabilized in Triton X-100. The anomalies were not observed when anti-ganglioside gamma-globulins were added to the incubation medium together with gangliosides or when the permeabilized embryos were incubated with gamma-globulins of normal rabbit serum. Pretreatment of S. intermedius embryos with serotonin, tryptamine or some other indole derivatives led to the disappearance of ganglioside determinants from the cell surface and sharply increased immunofluorescence within the cell. Such pretreatment of embryos increased the amount of cell-associated gangliosides more than threefold as compared to untreated embryos. Serotonin was shown to bind specifically to sea urchin gangliosides immobilized on octyl-Sepharose. These observations suggest that cell-surface gangliosides, after binding drugs, are internalized and that serotonin and its antagonists inhibit the transport of newly synthesized gangliosides to the cell-surface membrane.     

Effect of protein inhibitors of pancreatic proteinases on the breakdown and absorption of immunoreactive chicken ovalbumin in the intestines of adult rats

Adult male Wistar rats received protein mixtures containing chick ovalbumin (OVA) intragastrically, whereupon immunoreactive OVA was determined in the chymus of the gastrointestinal tract and in blood serum by the immunofluorescence technique and radioimmunoassay. Combined administration of OVA and the soybean inhibitor of trypsin suppressed the degradation of the antigenic structure of OVA in the intestine and augmentation of immunoreactive protein absorption. The suppression was less pronounced if OVA was combined with chick ovomucoid.     

Polymorphism of lactose genes in the dairy yeasts <Emphasis Type="Italic">Kluyveromyces marxianus</Emphasis>, potential probiotic microorganisms

Molecular karyotyping and Southern blot hybridization were used to investigate chromosomal polymorphism of the LAC genes controlling lactose fermentation in Kluyveromyces marxianus strains isolated from various dairy products and natural sources in Russia and CIS countries. Profound polymorphism of karyotype patterns and accumulation of LAC genes were observed in dairy K. marxianus strains. K. marxianus strains isolated from dairy products intensively fermented lactose at 37°C after one day of cultivation, while non-dairy strains exhibited delayed lactose fermentation or did not ferment it at all. Based on the fermentation tests, twelve K. marxianus strains were selected, which are of interest as potential probiotic microorganisms suitable for further molecular genetic studies and breeding.     

Next-Generation Techniques for Discovering Human Monoclonal Antibodies

Monoclonal antibodies have found wide applications in the treatment of cancer, as well as of autoimmune, infectious, and other diseases. Several dozen new antibodies are currently undergoing different stages of clinical trials, and some of them will soon be added to the list of immunotherapeutic drugs. Most of these antibodies have been generated using hybridoma technology or a phage display. In recent years, new methods of obtaining human monoclonal antibodies have been actively developing. These methods rely on sequencing immunoglobulin genes from B lymphocytes, as well as on the creation of antibody-secreting stable B-cell lines. The term next-generation antibody-discovery platforms has already been established in the literature to refer to these approaches. Our review focuses on describing the results obtained by these methods.     

Hybrid Selection of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> Yeasts for Thermotolerance and Fermentation Activity

Molecular genetic screening of Saccharomyces yeasts, isolated from natural sources in the regions of the world with a hot climate (Africa, South America, Southeast and Central Asia) was used for the search of thermotolerant S. cerevisiae strains. Based on physiological tests, four strains were selected that could grow at high temperatures (42 and 43°C) and had good fermentation activity: 7962-4B, 3529-7B, 52922-4-1-1A- 1C, and 87-2421.1-2A. Hybrids of monosporic culture of distiller’s race XII (XII₇-2) with the thermotolerant strains were obtained. Unlike the strain XII₇-2, which is unable to grow at above 39°C, all hybrids showed good growth at 42°C. Two of the six hybrids analyzed, H2-1 (87-2421.1-2A × XII₇-2) and H3-2 (7962-4B × XII₇-2), showed higher fermentation activity than the parental strains. According to the results obtained, inter-strain hybridization is an efficient method of obtaining S. cerevisiae strains, which combine thermotolerance with high efficiency of alcoholic fermentation.     

Multifractal Characterization of Butterfly Wings Scales

A lot of insect families have physical structures created by evolution for coloration. These structures are a source of ideas for new bio-inspired materials. The aim of this study was to quantitatively characterize the micromorphology of butterfly wings scales using atomic force microscopy and multifractal analysis. Two types of butterflies, Euploea mulciber (“striped blue crow”) and Morpho didius (“giant blue morpho”), were studied. The three-dimensional (3D) surface texture of the butterfly wings scales was investigated focusing on two areas: where the perceived colors strongly depend on and where they do not depend on the viewing angle. The results highlight a correlation between the surface coloration and 3D surface microtexture of butterfly wings scales.     

The effect of biogenic monoamine antagonists on the development of preimplantation mouse embryos cultured in vitro

The effect of serotonin and adrenaline antagonists was tested on the early embryos of mice of three lines. All the substances tested produced an arrest or inhibition of cleavage division and the appearance of anomalies. Serotonin introduced in the incubation medium was effective against some serotoninolytics. We were unable to test the protective effect of adrenaline, as in the concentrations used it has its own effect on the development. From the data obtained, a conclusion is made of the existence in early mouse embryos of the structures sensitive to serotonin and adrenaline antagonists. The assumptions is made from the previously obtained data on the presence of biogenic monoamines in early mouse embryos, of functional activity of prospective mediators of the nervous system at the earliest stages of embryonic development of mammals.