Rat brain reactions to acute brain stem lesion on dynamics of parameters of cerebral electric activity

Despite an old history of a question, adaptive brain reactions that develop after an acute brainstem lesion have not been adequately investigated. With the aim to study the central mechanisms of compensation/decompensation and to specify the character of involvement of orbitofrontal cortex and hippocampus into these processes the spatiotemporal organization of brain electric activity was analyzed in 8 rats before and after electrolytic brainstem lesion at the level of the lateral vestibular nucleus Deiters (VND). The electric activity was recorded from symmetric frontal and somatosensory cortical areas, hippocampal areas CA1, and intact VND. Spectralcoherent analysis showed that adaptive reactions are most clearly manifested by changes in the spatiotemporal organization of the theata activity: 1) early brainstemhippocampal synchronization of the electric activity in the frequency range of 6-7 Hz with subsequent involvement of anterior cortical regions is characteristic of survived animals; 2) independent hippocampal-cortical hemispheric system of excitation in the frequency of 4-5 Hz precedes the fatal outcome. On the day before the fatal outcome the interhemispheric coherence in the orbitofrontal cortex dropped, which suggests the involvement of these brain regions into the processes of visceral regulation.     

Intracerebral EEG functioning as a reflexion of the systemic brain organization in norm and pathology

The authors summarized the EEG findings and defined the nature of intercentral EEG relationships in different functional states of healthy subjects and patients with organic cerebral pathology based on coherence analysis. The EEG features typical of healthy subjects were identified: an anterior-posterior gradient of the mean coherence and the character of cortical-subcortical relationships in the anterior cerebral structures. Right- and lefthanded subjects showed the frequency and regional differences in EEG coherence, which reflected, mainly, specific intracortical relationships. Development and regression of pathologic signs in right- and lefthanded patients with organic brain lesions are thought to be determined by these differences. As distinct from cortical pathology, lesions of regulatory structures (diencephalic, brainstem, and limbic) were shown to produce more diffuse changes in intercentral relationships with a tendency to reciprocity. Intercentral relations, including their interhemispheric differences, varied with changes in the functional state of healthy subjects (increase and decrease in the level of functioning). A certain time course of changes in intercentral relationships was also revealed in patients with organic brain lesions during recovery of their consciousness and mental activity. Changes in the dominance of activity of individual regulatory structures are considered to be one of the most important factors that determine the dynamic character of EEG coherence.     

Characterization of 10 KDA prolamin genes in Phyllostachys aurea (Bambusoideae, Poaceae)

Prolamin is the dominant class of seed storage protein in grasses (Poaceae). Information on the 10 kDa multigene family coding for prolamins characteristic of the bambusoid-oryzoid grasses is limited. Two genes encoding 10 kDa prolamin were cloned and sequenced in the bambusoid species Phyllostachys aurea to assess the sequence diversity of this gene family in the oryzoid-bambusoid grasses. The genes, ~417 bp in length, were 96% similar at the DNA sequence level, differing in 12 base substitutions dispersed throughout the sequence. Eight of these mutations were nonsynonymous, leading to amino acid substitutions in the coding region, and one was nonsense, producing an amber stop codon. One gene had an open reading frame (ORF) of 139 amino acids, while the other gene had a shorter ORF (106 amino acids) due to the presence of a stop codon in the coding region and, thus, represents a pseudogene. Deduced proteins showed amino acid composition similar to that of rice. The study underscores the overall conserved nature of this multigene family and reflects considerable sequence divergence at the DNA and amino acid levels between the Oryza and the Phyllostachys genes. The systematic implication of the data is discussed in light of the inconsistent placement of Oryza in the Bambusoideae or Oryzoideae.     

Evolution of spore release mechanisms in the saprolegniaceae (Oomycetes): evidence from a phylogenetic analysis of internal transcribed spacer sequences

Classical studies on spore release within the Saprolegniaceae (Oomycetes) led to the proposition that different mechanisms of sporangial emptying represent steps in an evolutionary transition series. We have reevaluated this idea in a phylogenetic framework using internal transcribed spacer sequences of four genera. These data were compared with the response to osmotic stress exhibited by each taxon. Saprolegnia emerges as the most basal genus, sister to Achlya, Thraustotheca, and Dictyuchus. Achlya and Thraustotheca are most closely related, while Dictyuchus appears to have evolved along a separate evolutionary lineage. The resulting phylogenetic framework is consistent with the idea that the mechanism of sporangial emptying exhibited by Saprolegnia represents the plesiomorphic condition from which the other mechanisms were derived independently. These alternative mechanisms of spore release may have resulted from a small number of mutations that inhibited axonemal development and altered the temporal and spatial expression of lytic enzymes that degrade the sporangial wall. Copyright 1998 Academic Press.     

Changes in the diaphragm muscle and its feed artery after chronic respiratory airway obstruction in rats

A chronic respiratory load was produced in Wistar rats by tracheal binding to produce a twofold increase of pleural pressure oscillation amplitude during respiration. Eight weeks after the surgery, a higher proportion of type-I muscle fibers (MFI) in the costal diaphragm along with a greater MFI cross-section area and a higher succinate dehydrogenase activity in MFII in the crural diaphragm were observed. During recording the mechanical activity of ring preparations of diaphragm arteries under isometric conditions, an increase in endothelium-dependent relaxation was found, whereas endothelium-independent relaxation and arterial reactivity to noradrenaline did not change. Tracheal binding did not produce any changes of MF in the gastrocnemius muscle, but endothelium-dependent relaxation of gastrocnemius feed arteries was reduced. We conclude that chronic respiratory load affects the endothelial function in diaphragm arteries in a manner favorable for blood flow control in the diaphragm. Functional alterations in gastrocnemius arteries may be associated with the reduced locomotor activity of operated rats.     

Special traits of tissue lipids of whitefish <Emphasis Type="Italic">Coregonus lavaretus</Emphasis> living in water bodies with different anthropogenous load

The impact of water pollution on the content of lipid components of the liver and eggs of whitefish Coregonus lavaretus is investigated. The content of triacylglycerols (TAG), sphingomyelin (SPM), phosphatidylinositol (PI), and phosphatidylserine (PS) is higher in the liver of whitefish from polluted waters being a part of adaptogenous reactions (modification of permeability of biomembranes, of activity of membrane enzymes, etc.) providing a possibility of the survival of fish under unfavorable ecological factors. The lipid spectra of whitefish gonads are more stable in comparison with the liver. This may be related to protection of the reproductive system from external influences.     

Rotenone-insensitive NADH oxydation in mitochondrial suspension occurs by NADH dehydrogenase of respiratory chain fragments

Two types of NADH oxidation, rotenone-sensitive and rotenone-insensitive, in suspension of beef heart mitochondria were investigated by the spectrophotometric method. The oxidation of the added NADH by mitochondria in hypotonic media occurs only through the NADH dehydrogenase of the respiratory chain, since it was totally blocked by rotenone or amytal (and also by antimycin A or azide), but the ferricyanide-activated NADH oxidation was insensitive to these inhibitors. The insensitivity of the NADH dehydrogenase to rotenone appears to be due to a shunt of the electron transfer to ferricyanide without involving of ubiquinone. Both types of the oxydation occur through one and the same enzyme, which exists in two states. The evidence in favour of this is that NAD+ and DTT slightly influence the first type of oxidation but strongly inhibit the second one. The ferricyanide-activated NADH oxidation takes place in NADH dehydrogenase fragments released from mitochondria. Low Ds-Na concentrations block the respiratory chain NADH oxidation but increase the velocity of the ferricyanide-dependent oxidation. Probably, the increase is the result of the detergent-induced additional releasing of the fragments. The express-method for the preparation of the initially purified fraction with a high yield of detergent-containing fragments of the active enzyme is described.