The diagnosis of antileptospiral antibodies in human subjects by solid-phase immunoenzyme analysis

The possibility of using the enzyme-linked immunosorbent assay (ELISA) for the diagnosis of leptospirosis has been shown. This method has proved to be more simple and sensitive than the leptospiral microagglutination and lysis test. The data on obtaining genus-specific leptospiral antigens are presented. As revealed in this study, the antigens obtained by the complex treatment of microbial cells with ultrasound and detergents show the maximum activity in ELISA. The optimum parameters of the ELISA system for the diagnosis of leptospirosis have been established.     

Applications of fluorescent semiconductor nanocrystals in microscopy and cytometry

Quantum dots (QD) nanocrystals consisting of CdSe core with ZnS shell are a novel class of fluorophores with tremendous potential in microscopy and cytometry techniques. The unique optical features of Qdots, namely, high photostability and extinction coefficient, wide absorption and narrow emission spectra, and large Stokes shift make them desirable fluorescent tags for diverse biomedical applications. Applications of this novel technology in microscopy and cytometry produce reliable multicolor specimens due to increased photostability, ability for multiplexing and narrow emission spectra of nanocrystals. QD conjugates are available on the market and could be prepared in the laboratory. This paper describes the application of QD-conjugates for immunophenotyping and FISH assessment of cells and tissues, and the requirements for microscope and flow cytometer reengineering for successful use of QD in multiplex fluorescent format. Despite the considerable progress, important methodological issues still need to be solved in terms of QD nanocrystals' size, heterogeneity, functionalization and stability of their conjugates. We discuss practical approaches and challenges that need to be addressed to make QD immunostaining a standard method in biology.     

Cell sorting in cancer research—Diminishing degree of cell heterogeneity

Increasing evidence of intratumor heterogeneity and its augmentation due to selective pressure of microenvironment and recent achievements in cancer therapeutics lead to the need to investigate and track the tumor subclonal structure. Cell sorting of heterogeneous subpopulations of tumor and tumor-associated cells has been a long established strategy in cancer research. Advancement in lasers, computer technology and optics has led to a new generation of flow cytometers and cell sorters capable of high-speed processing of single cell suspensions. Over the last several years cell sorting was used in combination with molecular biological methods, imaging and proteomics to characterize primary and metastatic cancer cell populations, minimal residual disease and single tumor cells. It was the principal method for identification and characterization of cancer stem cells. Analysis of single cancer cells may improve early detection of tumors, monitoring of circulating tumor cells, evaluation of intratumor heterogeneity and chemotherapeutic treatments. The aim of this review is to provide an overview of major cell sorting applications and approaches with new prospective developments such as microfluidics and microchip technologies.     

From an increase in the number of tandem repeats through the decrease of sialylation to the downregulation of MUC1 expression level

Enhanced glucose uptake by cancer cells was demonstrated in many studies in vitro and in vivo. Glycolysis is one of the main ways of obtaining energy in hypoxia conditions. However, in addition to energy exchange, carbohydrates are also necessary for the posttranslational modification of the protein molecules. Cancer cells are often characterized by an enhanced expression of different glycoproteides. Correct glycosylation defines the structure and activity of such molecules. We demonstrated that under the same cultivation conditions, the intensity of glycosylation does not depend on the total number of potential O-glycosylation sites in one molecule. As a model for the investigation, the tandem repeat region (region with variable number of tandem repeats) of the human mucin MUC1, in which each of the repeats carries four potential O-glycosylation sites, was used. An increase of the tandem repeat number in the recombinant protein did not lead to a proportional increase in the level of sLe^a glycosides. A consequence of this was a reduction in the number of recombinant proteins associated with the cytoplasmic membrane at an overall high expression level. Prolongation of the cultivation duration led to a reduction in the expression level of the recombinant proteins by up to 30% of the initial level, and the intensity of this reduction was in a direct ratio to the number of tandem repeats in the protein molecule.     

Production of Stable Cell Lines on the Basis of the Cultured RPMI 8866 B-Cells with Constant and Inducible Expression of the Human Immunodeficiency Virus Tat Protein

Russian Journal of Developmental Biology - Highly-efficient antiretroviral therapy allows controlling human immunodeficiency virus (HIV) and preventing the development of immunodeficiency. However,...     

Fluorescent semiconductor nanocrystals in microscopy and flow cytometry

Quantum dots nanocrystals (Qdots or QDs), consisting of a CdSe core with a ZnS shell, are a novel class of fluorochromes with significant advantages over traditional organic fluorochromes and fluorescent proteins. QDs have a large extinction coefficient, high photostability, wide absorption and narrow emission spectra, and large Stokes shifts. These features make them desirable for both microscopy and flow cytometry. Applications of QD-conjugates with antibodies, streptavidin, and DNA or RNA probes have made it possible to produce highly stable multicolor specimens useful for scientific and diagnostic purposes. The current review describes the achievements in preparation of multicolor specimens based on QD-conjugates for microscopy and flow cytometry and outlines the requirements for microscope and flow cytometer reengineering for successful analysis of these specimens. However, despite considerable progress, two of the obstacles that preclude wider use of QDs include some of their chemical properties and the large size of QD-conjugates. Difficulties in the application of QDs are similar whether commercial or custom-made conjugates are used.