Biophysical methods for biochip analysis. Use of wide field digital fluorescent microscopy

This paper discusses an issue on the development of biophysical methods for biochip analysis. A scheme and construction of a biochip analyzer based on wide-field digital fluorescence microscopy are described. The analyzer is designed to register images of biological microchips labeled with fluorescent dyes. The device developed is useful for high-sensitive throughput recording analyses by biochips after interaction of immobilized probes with fluorescently labeled sample molecules as well as it provides the higher rate of the analysis compared to laser scanning devices. With this analyzer a scope where biological microchips can be applied becomes wider, the development of new protocols of the analyses is possible and standard analyses run faster with the use of biochips, the expenses for the analysis performance can be reduced.     

Contemporary concepts of homology in biology (a theoretical review)

A brief review of the contemporary theoretical concepts of homology being developed basically in systematics and phylogenetics as well as in developmental biology is presented. Ontologically, both homology and analogy represent a kind of correspondence considered from the standpoint of nominalism, realism, and conceptualism. According to their nominalistic treatment, both are described by a set-theory approximation which makes them classes (in the logical sense). The realistic treatment provides their holistic view according to which a homologue is an anatomical or evolutionary singular while analogue remains a class. The conceptualistic treatment means that there are real (objective) correspondences existing among real (objective) entities while fixation of any of them is based on certain theoretical presumptions adopted by a researcher; homology as a natural kind (including homeostatic property cluster) seems to be most consistent with such a treatment. Realistic view of homology makes it "absolute", while two others make discrimination of homology and analogy strictly relative. Two basic general homology concepts have been developed in recent literature--taxic and transformational ones; the first considers respective correspondences as structure relations, the second as process relations. The taxic homology is nearly the same as classical typological one (Owen), while transformational homology unites all its phylogenetic, ontogenetic (developmental) and transformation-typological definitions. Process-structuralistic approach seems to unite both taxic and transformational ones. The latter makes it possible to apply general homology concept not only to structures but to processes as well. It is stressed that homology is not identical to the similarity, the latter being just the means for revealing the former. Some closer consideration is given to phylogenetic, ontogenetic and genetic treatments of homology; significant uncertainty is shown to exist between them which causes the "homology problem". Epistemologically, any homology statement has a status of hypothesis which makes such a statement theory-dependent according to the hypothetic-deductive argumentation scheme. This dependence allows to stress once more the relative nature of homology and analogy correspondences. Some questions concerning operational concepts and criteria of homology are considered. A hierarchical concept of homology seems to be the most promising prospect of future development of the "homology problem".     

The biological effects in animals related to the accident at the Chernobyl Atomic Electric Power Station. 2. The state of bone marrow hematopoiesis in rats]

It has been shown that rats born during the first months after the Chernobyl A.P.S. disaster exhibit essential changes in the peripheral blood and bone marrow haemopoiesis throughout the entire lifetime. Rats brought up in Chernobyl from the age of three months on display even more pronounced changes. It is assumed that the changes in the haemopoiesis develop due to the continuous influence of low-level radiation of different quality and are attributed to the effect of the incorporated radionuclides.     

The ratio of coat protein to bacteriophage f2 RNA in the translational repressor complex]

One of the mechanisms underlying the regulation of the bacteriophage f2 RNA translation is the repression of the phage RNA-replicase formation by coat protein. This repression is due to the formation of a complex between f2 RNA and coat protein (complex I). In this work the mechanism of complex I formation as well as the effect of this complex on the f2 RNA-replicase formation was followed by inhibition of alanine incorporation into RNA-replicase polypeptide which was separated by polyacrylamide gel electrophoresis. The molar ratios of protein to f2 RNA in complex I were analyzed by sucrose gradient sedimentation. It was been found that complex I consists of six molecules of coat protein bound per one molecule of RNA. Ribonuclease digestion of the glutaraldehyde-fixed complex resulted in a mixture of products in which the hexamers of coat protein molecules were predominant. This indicates that the six molecules of coat protein bound to f2 RNA are neighbouring. It has been also shown that under conditions required for phage protein synthesis, coat protein occurs in solution is dimer. The results show that the translational repression of the RNA-replicase cistron is due to the cooperative attachment of three dimers of coat protein to phage template, forming a hexameric cluster on the RNA strand. The proposed mechanism of the complex I formation seems to be in good agreement with the sequence of events in the phage F2 life cycle. It is known that shortly after infection of the host cell the coat protein and phage RNA-replicase begin to be synthesised. According to our findings, the first portions of coat protein do not affect the translation of the RNA-replicase gene since at low concentration the coat protein occure in the form of monomers. At a later period of phage development, when the concentration of coat protein is sufficiently high to promote the formation of protein dimers, the translational repressor complex is formed and the RNA-replicase gene becomes inoperative.     

The cytotoxic effect of heavy metals on an L-cell culture

The dependence of some parameters of L-cells culture viability on different concentrations of heavy metals was studied. Considerable cytotoxic effect of low concentrations of nickel (0.025 mcg/ml) and lead (0.05 mcg/ml) was shown. Copper and chrome at concentrations of 0.25-0.5 mcg/ml promote cells proliferation between third and fifth days of cultivation. Nickel at concentration 0.025 mcg/ml and lead at all investigated concentrations synchronize cells division in culture. Increasing of giant polynucleas cells level in culture was characteristic for investigated metals. The maximum levels of this type cells were caused by the action of nickel, chrome and copper.     

The analysis of biochemical markers of MCF-7 cells apoptosis induced by recombinant analog of lactaptin

Earlier we isolated and characterized human milk pro-apoptotic peptide - lactaptin and generated its engineered analog - RL2. It was shown that both lactaptin and RL2 are capable to induce apoptotic death of MCF-7 cells. In this report we have analyzed biochemical markers of RL2 induced MCF-7 apoptosis. The activation of initiator and effector caspases as well as mitochondrial membrane potential and cytoplasm membrane changes were analyzed using flow cytometry and Western-blot methods. We have found that RL2 induced apoptotic death of MCF-7 cells was accompanied by PS exposure on the plasma membrane surface. It also was shown that RL2 has induced dissipation of mitochondrial membrane potential and resulted in activation of initiator caspases 8, 9 and effector caspase 7.     

Temporal characteristics of the initial stage of the verbal information processing in healthy subjects and in schizophrenia

The study aimed to investigate the early coding of visually presented words and pseudowords using event-related potentials (ERP). We conducted comparative analysis of the characteristics of P100 and N170 in healthy controls and in patients with the first episode of schizophrenia during passive perception of verbal stimuli as well as under conditions of relevant words and pseudowords. The latency of early ERP components P100 and N170 appeared to be shorter in comparison with healthy subjects in the temporal, parietal and occipital areas. The latency of P100 in patients was significantly shorter in the temporal, parietal and occipital areas, whereas the latency of N170 was shorter in the parietal and occipital areas than in controls. The latency of N170 in healthy subjects was significantly longer to words than to pseudowords and in patients - vice versa. The latencies of N170 in all TPO areas were equal in healthy subjects during word processing, and this equality was upset during non-word processing. In patients with schizophrenia the equality was upset, but, opposite to healthy patients, the upset of equality was more expressed during words processing. Thus, the early stage of verbal information processing in schizophrenic patients is insufficient in time. The time deficit of the automatic processes may lead to defective processing of overall information.     

Identification of allelic state of leaf rust-resistance Lr34 gene in the cultivars of soft winter wheat of Ukrainian breeding

The distribution of alleles at the Lr34 locus associated with leaf rust resistance among winter common wheat (Triticum aestivum L.) cultivars of Ukrainian breeding was studied. Co-dominant molecular-genetic marker cssfr5 was used for detection of the allelic condition of the Lr34 locus. The cultivars with detected allele Lr34(+) were identified as potentially "resistant" and the cultivars in which detected allele Lr34(-) were identified as potentially "susceptible". The collection of the cultivars (81 ones), created in the main plant breeding centers of Ukraine was analyzed. The allele Lr34(+) was identified in 44% cultivars. Results were compared with the data about the distribution of the Lr34(+) in cultivars created in different countries.