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.     

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.     

Molecular genetic and physiological differentiation of <Emphasis Type="Italic">Kluyveromyces lactis</Emphasis> and <Emphasis Type="Italic">Kluyveromyces marxianus</Emphasis>: Analysis of strains from the all-Russian collection of microorganisms (VKM)

Molecular genetic identification of 52 Kluyveromyces strains from VKM, mainly of dairy origin, was carried out. Restriction analysis of 5.8S-ITS rDNA fragments was used to differentiate between Kl. lactis var. lactis, Kl. lactis var. drosophilarum (European population of “krassilnikovii”), and Kl. marxianus. Kl. lactis was shown to differ from Kl. marxianus in its ability to assimilate α-glucosides: maltose, melezitose, and α-methyl-glucoside.