Preparation of soybean seed samples for FT-IR microspectroscopy

Typical preparation of seed samples for infrared (IR) microspectroscopy involves imbibition of the seed for varying time periods followed by cryosectioning. Imbibition, however, may initiate germination even at 4° C with associated changes in the chemistry of the sample. We have found that it is possible to section seeds that are sufficiently hard, such as soybeans, on a standard laboratory microtome without imbibition. The use of dry sectioning of unimbibed seeds is reported here, as well as a comparison of different mounting media and modes of analysis. Glycerol, Tissue-Tek, and ethanol were used as mounting media, and the quality of the resulting spectra was assessed. Ethanol was the preferred mountant, because it dried quickly with no residue and thus did not interfere with the spectrum of interest. Analysis in transmission mode using barium fluoride windows to hold the samples was compared with transmission-reflection analysis with sections mounted on special infrared-reflecting slides. The two modes of analysis performed well in different regions of the spectrum. The mode of analysis (transmission vs. transmission-reflection) should be based on the components of greatest interest in the sample.     

A study of the functional activity of macrophages of peritoneal exudate of mice exposed to low-intensity laser radiation in vitro and in vivo

The effect of low-intensity laser radiation generated by semiconductor devices in the red (650 nm) and infrared (850 nm) regions of the spectrum in vitro and in vivo on the phagocytic activity and synthesis of proinflammatory cytokines by peritoneal macrophages during the phagocytosis of bacterial cells has been studied. A culture of the clinical strain of the enteropathogenic bacterium Escherichia coli was used as an object. The radiation dose was varied by changing the power and duration of exposure. The results obtained indicate that infrared low-intensity laser radiation has a stimulating effect on the phagocytic activity of macrophages. It was shown that the effect of low-intensity laser radiation on the activity of the phagocytic process, the enhancement of the adhesion of bacteria by macrophages, killing of bacteria, and the production of proinflammatory cytokines is dose-dependent. The exposure to the rays of the red region of the spectrum on phagocytizing macrophages induced a decrease in their activity; as the dose was increased, the destruction of cells was registered.     

Activity of murine peritoneal macrophages upon weak red and infrared laser irradiation in vitro and in vivo

The phagocytic activity and production of proinflammatory cytokines by murine peritoneal macrophages was examined upon in vitro and in vivo exposure to low doses (up to 150 mJ/cm²) of red (650 nm) and infrared (850 nm) light generated by semiconductor lasers. Infrared irradiation proved stimulatory in a dose-dependent way for phagocytosis and killing of enteropathogenic Escherichia coli as well as for cytokine production. Red light markedly enhanced cytokine production but was detrimental to macrophage activity and at higher doses caused their destruction.     

Features of Morphogenesis of Iris ensata Thunb. in vitro Culture

Russian Journal of Plant Physiology - This paper presents a protocol for in vitro culture of Iris ensata Thunb. and the results of a histological analysis of subsequent morphogenesis stages. To...     

Ultrathin structure of normally growing and regenerating cells of Acetabularia mediterranea]

The ultrastructure of nucleus and cytoplasm in regenerating cells of Acetabularia mediterranea differs from that in normally growing ones: the nucleus of regenerating cells form numerous outgrowths; the cortical layer of nucleolus disintegrates markedly; the emission of nucleolar material in the nucleoplasm is observed. In the cytoplasm the portion of active chloroplasts increases and a great number of tubular fibrils appears. In the cytoplasm of regenerating cells the Golgi dictyosomes occur more frequently and the vesicles at their ends are larger than in that of normally growing cells. The changes of macromolecular organization of the nucleus and cytoplasm in question observed at the earlier stages of regeneration (2--12 hrs) suggest the increase of metabolic activity of cells.     

Cytomorphological changes in human tumor cells exposed to high-polar compounds

The effects of some high-polar compounds on the cytomorphological characteristics of cultured cells of synovial and osteogenic human sarcomas (Sa-2 and Sa-4) were studied. Incubation of Sa-2 cells with 1 or 2% dimethylsulfoxide (DMSO) or 100 mM dimethylformamide (DMF) during 4-6 days induced the cellular, structural and functional changes in Sa-2 cells which were considered as manifestations of pseudoepithelial differentiation. DMSO did not influence the activity of Sa-2 cell enzymes, while DMF suppressed their activity, mainly that of acid and alkaline phosphatases. DMSO and DMF induced in Sa-4 cultured the appearance of the cells which were similar cytomorphologically to normal osteoblasts. DMSO and DMF significantly depressed the activity of acid phosphatase in Sa-4 cells and transformed the positive reaction of alkaline phosphatase to the negative one. DMSO and DMF prolonged the time of the doubling of Sa-2 and Sa-4 cells. The effects of DMSO and DMF were reversible. Methylformamide (200 mM) and dimethyl acetamide (0,1 and 10 mM) did not induce analogous changes in human sarcoma cells.     

Regularities of the content and organization of pyrimidine oligonucleotide sequences in insect DNA

Certain regularities in content and organization of pyrimidine oligonucleotide sequences of DNA from 15 insect species belonging to 4 orders were studied. The degree of nucleotide clusterization in insect DNA was found to be species-specific, being the highest in Hymenoptera and lowest in Lepidoptera; the Blattodea and Coleoptera occupy an intermediate position by this index between them. The changes in the DNA cluster structure during the evolution of insect species are not of vector type; the degree of clusterization of DNA nucleotide is either increased (Hymenoptera) or decreased (Lepidoptera as compared with Blattodea). In the DNA oligonucleotide fractions containing both pyrimidine nucleotides the percentage content of thymidyl nucleotides is much higher than that of cytidyl nucleotides, the thymine content being increased with the lengthening of oligopyrimidine clusters. The insect species with a higher degree of clusterization of DNA pyrimidine nucleotides contain more thymidyl nucleotide residues. These results agree well with the hypothesis suggesting that during the evolution of large taxons the accumulation of long pyrimidine sequences in animal DNA is accompanied by an increase of thymidyl nucleotide content in them. This can largely be due to the increase of matrix resistance during the evolution and is biologically significant for animals of any taxons, including insects.     

An analysis of the DNA synthesized in adenovirus-infected cells under exposure to nucleoside analogs

The method of dot DNA-DNA hybridization was used to reveal the inhibition of the synthesis of the adenoviral DNA by 6-azacytidine, cyclocytidine and ribamidyl in the adenovirus-infected cells Hep-2, a degree of which depended on the preparation concentration.