[The C-terminus of transcription factor TnrA from Bacillus subtilis controls DNA-binding domain activity but is not required for dimerization].

The transcription factor ThrA, which belongs to the MerR transcription regulators, in Bacillus subtilis cells controls genes of nitrogen metabolism under conditions of nitrogen limitation. As all the DNA-binding proteins, it is present as a dimer in cells, but the dimerization site is still unknown. The multiple alignment of TnrA homologs from the other Bacilli allowed to identify the putative dimerization sites. Using the C-terminal truncated TnrA proteins it is established, that, in contrast to other MerR-proteins, the TnrA C-terminus does not participate in dimerization. The surface plasmon resonance has revealed that C-terminus truncations of TnrA do not inactivate its DNA-binding activity. By contrary, it increased an affinity to DNA, confirming that C-terminus controls the DNA-binding activity in a full-length TnrA.

[The role of AmtB, GlnK and glutamine synthetase in regulation of transcription factor TnrA in Bacillus subtilis].

The nitrogen is a macroelement for all alive cells, from bacteria to animals. Although NH3/NH4+ are highly toxic to animal, they are the preferred source of nitrogen for the most microorganisms and are assimilated by glutamine synthetase in the GOGAT cycle. The nitrogen limitation triggers a number of regulatory processes and activates many genes, providing the utilizing of alternative nitrogen sources. In Bacillus subtilis the genes of nitrogen metabolism are regulated by the transcription factor TnrA. In a cells it is bound to AmtB-GlnK proteins, the interaction with Glutamine synthetase (GS) represses its DNA-binding activity. Here we show the lack of AmtB leads to the nitrogen deficiency in a cell and, consequently, the increased expression of TnrA-dependent genes. In the lack of GlnK the transcription factor TnrA is constitutive bound to GS, the TnrA activity is repressed even under nitrogen limit conditions. Apparently, the TnrA activity is subjected to permanent repression by GS. In the absence of GS, the TnrA activity is strongly higher in compare to control, even under nitrogen limitation, when GS is active. These data allow to suggest that TnrA activity is regulated by the competitive binding to GlnK and GS.

[Structure of the insular area in the rat cerebral neocortex]. / Stroenie insuliarnoi oblasti novoi kory mozga krysy.

The cytoarchitectonics of brain insular area was studied in albino rat. It was found that this part of neocortex is subdivided into two subareas, each consisting of two fields. The peculiar features of cytoarchitectonics of these subareas and fields are presented. A topographic map is suggested, describing their position on the lateral surface of cerebral hemisphere. Classification of insular area subdivisions, suggested in the present study, is discussed in connection with the data of other authors.

A simple surgical method for immobilizing the cat eye.

In this article we describe a new method for surgical immobilization of the cat eye in which 3 motor nerves are simultaneously destroyed where they converge in the orbital fissure. The method depends upon inserting a special instrument 'spoon' through the soft palate into the orbital fissure.

[Role of the visual cortex in organizing eye movements induced by local electric stimulation of the lateral geniculate body of the cat]. / Rol' zritel'noi kory v organizatsii dvizhenii glaz, vyzvannykh lokal'noi élektricheskoi stimuliatsiei naruzhnogo kolenchatogo tela koshki.

Eye movements evoked by local electrical stimulation of the dorsal nucleus of the lateral geniculate body were analyzed in cats with extirpated visual cortex and in intact cats. The experiments were performed in alert cats. There were no differences between the obtained spatial characteristics of eye movements evoked by electrical stimulation in experimental and intact cats. These results suggest that visual cortical areas are not the main and necessary links in the chain for signal transmission (evoked by electrical stimulation of lateral geniculate body) from subcortical parts of the direct visual pathway to acting links of the oculomotor system. The possible pathways for transmission of information from the dorsal nucleus of the lateral geniculate body to structures of the oculomotor system are discussed.

[Retino-pulvinar pathway of the cat brain]. / Retino-pul'vinarnyi put' golovnogo mozga koshki.

Peculiarities on axonal distribution and termination of the retinal ganglionar cells within the limits of the thalamic pulvinar nuclei have been studied in 10 cats by means of the radioautography method combined with silver nitrate impregnation (Fink--Heimer technique). The ganglionar cells have projections on two pulvinar nuclei -- the lateral and the inferior. The medial pulvinar nucleus has no similar connections. The retinal projections in the pulvinar nuclear complex are bilateral and nearly symmetrical, the contralateral projections of the pathway somewhat predominate.

[Analysis of photic signals by cats according to their intensity following transection of the superior quadrigeminal brachii]. / Analiz koshkoi svetovykh signalov po intensivnosti posle peresecheniia ruchek verkhnikh bugrov chetverokholmiia.

In experiments on cats trained by the motor alimentary conditioned method to discriminate photic stimuli by intensity, EEG changes were studied when differentiating signals of different biological significance before and after transection of the brachii of the superior colliculi. The normal direct proportional dependence of pronouncedness of brain electrical reactions on the complexity of stimuli analysis was disturbed after transection. The operated animals retained only the capacity for a rough differentiation by brightness, the fine gradation of EEG responses to negative signals of different fineness being lost. The disturbance of interaction between the analysing and activating brain systems after transection of the brachii may be due to both the lack of non-specific ascending tonic influences of the midbrain reticular formation on the cortex, and to the destruction of many pathways for corticofugal control of the activity of the brainstem non-specific apparatus.

[Organization of retinal and lateral geniculate body connections with the hypothalamus in cats]. / Organizatsiia sviazei setchatki i naruzhnogo kolenchatogo tela s gipotalamusom u koshki.

In order to clarify connective relations between the optic system and activating formations, the pathways from the retina and the external geniculate body to the hypothalamus were investigated in the cat. Methods of Fink--Heimer and of I. V. Victorov were applied. The retina and the dorsal nucleus of the external geniculate body were stated to have efferent connections with the same nuclei in the anterior hypothalamus. Medial and posterior hypothalamus do not accept such connections. Retino-hypothalamic and geniculate hypothalamic pathways are demonstrated to terminate in the supraoptic and suprachiasmic nuclei. These pathways are bilateral and quantitatively equivalent.