Intrusive growth of flax phloem fibers is of intercalary type.

Flax (Linum usitatissimum L.) phloem fibers elongate considerably during their development and intrude between existing cells. We questioned whether fiber elongation is caused by cell tip growth or intercalary growth. Cells with tip growth are characterized by having two specific zones of cytoplasm in the cell tip, one with vesicles and no large organelles at the very tip and one with various organelles amongst others longitudinally arranged cortical microtubules in the subapex. Such zones were not observed in elongating flax fibers. Instead, organelles moved into the very tip region, and cortical microtubules showed transversal and helical configurations as known for cells growing in intercalary way. In addition, pulse-chase experiments with Calcofluor White resulted in a spotted fluorescence in the cell wall all over the length of the fiber. Therefore, it is concluded that fiber elongation is not achieved by tip growth but by intercalary growth. The intrusively growing fiber is a coenocytic cell that has no plasmodesmata, making the fibers a symplastically isolated domain within the stem.

[Effect of anticholinesterases on acetylcholinesterase distribution in the human and animal brain (cytochemical study)]. / Osobennosti raspredeleniia atsetilkholinésterazy v mozge cheloveka i zhivotnykh pri deistvii na organizm atsetilkholinésteraznykh veshchestv (tsitokhimicheskoe issledovanie).

With the use of quantitative histochemistry and cytochemistry methods the localization of acetylcholinesterase in the brain of man and animals in cases of acute poisoning with organophosphorus compounds was studied. In the brain of animals poisoned with chlorophos the activity of the enzyme, according to cytophotometric findings, dropped 2 or 3 times, this drop being more pronounced in the neuropile. In the human brain, the drop of the acetylcholinesterase activity caused by organophosphorus compounds was the most pronounced in the neuropile and the neurons of the cortex, caudate nucleus and hypothalamus. The cytochemical examinations of the enzyme in the cases of poisoning showed absence of the sediment on the basal membrane of the capillaries and the membranes of the nervous fibres and synapses. However, acetylcholinesterase was found to remain active in some neurons at the nuclear membrane and in the endoplasmic reticulum (presence of the sediment in the form of individual granules or discrete zones). Probability of the acetylcholinesterase activity inhibition mainly in the outer (in relation to the neuron) barrier systems and possibility of reparative processes in the neurons are discussed.

[Distribution of acetylcholinesterase in different regions of the human brain according to light and electron cytochemical findings]. / Raspredelenie atsetilkholinésterazy v razlichnykh otdelakh mozga cheloveka po dannym svetovoi i élektronnoi tsitokhimii.

On the basis of cytochemical studies the author presents some data, concerning the distribution of acetycholinesterase in the structures of human brain nervous tissues on the photo-optical and ultrastructural levels. There were some differences in the distribution of enzymes in the different brain areas. There were also some special traits in the cytochemical reactions to acethylcholinestherase in connection with the processes of postmortal autolysis and the state of the brain taken for studies. It is assumed that there are 2 forms of acethylcholinestherase in the cells--connected and not connected with the membranes. The author discusses some problems of the synaptical and barrier functions of acetylcholinestherase in the brain as well as the functional significance of the cholinergic system of mediation in relation to its distribution in different brain areas.

[Nucleic acid concentration in the brains of inbred rats of different strains]. / Soderzhanie nukleinovykh kislot v mozge inbrednykh krys razlichnykh linii.

The changes of nucleic acids content in the formation of conditioned skin-defence reflex was studied on inbred rats of various strains. In WGA rats the reflex was formed on the average aight stimulations. An increased RNA content was discovered by cytophotometric determination of the nucleic acids content in the neurons and perineural glia of the cerebral cortex in August rats only. It is assumed that an increased RNA synthesis in the animals of this strain can serve as the basis for their better training.

[Electron-cytochemical distribution of acetylcholinesterase, monamine oxidase and Mg2+-ATPase in the human hypothalamus]. / Elektronno-tsitokhimicheskoe raspredelenie atsetilkholinésterazy, monoaminooksidazy i Mg2+-ATF-azy v gipotalamuse cheloveka.

The distribution of acetylcholinesterase, monoaminoxidase and ATP-ase was studied in human hypothalamus by means of electron microscopy. The study demonstrated a possibility of differentiation of the hypothalamic neurons according to phases of neurosecretion. These data were achieved on the basis of electron cytochemistry in detecting ATP-asa in the nuclei of neurons. Comparing literary data concerning the nonmediator role of acetyl-choline and catecholeamines with personal studies, the authors demonstrate the internal and external barrier functions of acetylcholinesterase and monoamineoxidase in the brain.

[A quantitative assessment of enzyme activity by cytophotometry using a standard]. / Kolichestvennaia otsenka aktivnosti fermentov metodom tsitofotometrii s primeneniem étalona

The usage of the standard has been offered in cytospectrophotometrical measurements of enzymatic activities that are revealed histochemically. A tetrazolium method was used to demonstrate lactate dehydrogenase activity in sections of the rat brain. As a standard, a mixture of the enzyme (a crystalline forme of LDG) and gelatine was taken. The method of standardization permits fulfilling a quantitative comparison of heterogenic biological materials.