Elemental distribution in striated muscle and the effects of hypertonicity: Electron probe analysis of cryo sections

A method of rapid freezing in supercooled Freon 22 (monochlorodifluoromethane) followed by cryoultramicrotomy is described and shown to yield ultrathin sections in which both the cellular ultrastructure and the distribution of diffusible ions across the cell membrane are preserved and intracellular compartmentalization of diffusabler ions can be quantitated. Quantitative electron probe analysis (Shuman, H., A.V. Somlyo, and A.P. Somlyo. 1976. Ultramicros. 1:317-339.) of freeze-dried ultrathin cryto sections was found to provide a valid measure of the composition of cells and cellular organelles and was used to determine the ionic composition of the in situ terminal cisternae of the sarcoplasmic reticulum (SR), the distribution of CI in skeletal muscle, and the effects of hypertonic solutions on the subcellular composition if striated muscle. There was no evidence of sequestered CI in the terminal cisternae of resting muscles, although calcium (66mmol/kg dry wt +/- 4.6 SE) was detected. The values of [C1](i) determined with small (50-100 nm) diameter probes over cytoplasm excluding organelles over nuclei or terminal cisternae were not significantly different. Mitochondria partially excluded C1, with a cytoplasmic/ mitochondrial Ci ratio of 2.4 +/- 0.88 SD. The elemental concentrations (mmol/kg dry wt +/- SD) of muscle fibers measured with 0.5-9-μm diameter electron probes in normal frog striated muscle were: P, 302 +/- 4.3; S, 189 +/- 2.9;C1, 24 +/- 1.1;K, 404 +/- 4.3, and Mg, 39 +/- 2.1. It is concluded that: (a) in normal muscle the "excess CI" measured with previous bulk chemical analyses and flux studies is not compartmentalized in the SR or in other cellular organelles, and (b) the cytoplasmic C1 in low [K](0) solutions exceeds that predicted by a passive electrochemical distribution. Hypertonic 2.2 X NaCl, 2.5 X sucrose, or 2.2 X Na isethionate produced: (a) swollen vacuoles, frequently paired, adjacent to the Z lines and containing significantly higher than cytoplasmic concentrations of Na and Cl or S (isethionate), but no detectable Ca, and (b) granules of Ca, Mg, and P = approximately (6 Ca + 1 Mg)/6P in the longitudinal SR. It is concluded that hypertonicity produces compartmentalized domains of extracellular solutes within the muscle fibers and translocates Ca into the longitudinal tubules.     

Functional characteristics of the principal intrinsic systems of hippocampal connections

By extracellular recording of unit activity and electrical stimulation of unanesthetized rabbits the character of the following principal intrinsic hippocampal connections was investigated: fascia dentata with area CA₃ (series FD-CA₃) and area CA₃ with area CA₁ (series CA₃-CA₁). Differences between the functional characteristics of these two systems of connections were shown. The CA₃-CA₁ system was highly efficient, with a sharply defined boundary between subthreshold and threshold intensities of stimulation and with a wide range of active frequencies; recruiting was negligible and no sign of prolonged potentiation was present. The FD-CA₃ system was characterized by low efficiency, a wide threshold zone, and narrow range of active frequencies, slow recruiting, and long preservation of incoming influences. The probability that these functional differences depend on the morphological characteristics of the systems of connections and their possible role in the function of the hippocampus are discussed.Institute of Biological Physics, Academy of Sciences of the USSR, Pushchino-on-Oka. Translated from Neirofiziologiya, Vol. 8, No. 3, pp. 259–266, May–June, 1976.     

Sensory characteristics of the cortical input of the hippocampus, the dentate fascia]

Investigation of sensory reactions of the neurones of the dentate fascia was performed in unanaesthetized rabbits. Spontaneous activity usually consisted of long aperiodic high-frequency bursts with silent periods between them. Multimodal convergence was observed in 76% of records. Responses to sensory stimuli constituted three nearly equal groups: 1 -- tonic inhibitory reactions; 2--phasic (equal to stimulus duration) activatory responses; 3--simple "specific" responses of on-type, sometimes with secondary phasic components. In one microelectrode track, perpendicular to the double lamina of granular cells, all neurones usually responded in the same fashion.     

Phenomenon of music-induced opening of the blood-brain barrier in healthy mice

Music plays a more important role in our life than just being an entertainment. For example, it can be used as an anti-anxiety therapy of human and animals. However, the unsafe listening of loud music triggers hearing loss in millions of young people and professional musicians (rock, jazz and symphony orchestra) owing to exposure to damaging sound levels using personal audio devices or at noisy entertainment venues including nightclubs, discotheques, bars and concerts. Therefore, it is important to understand how loud music affects us. In this pioneering study on healthy mice, we discover that loud rock music below the safety threshold causes opening of the blood-brain barrier (OBBB), which plays a vital role in protecting the brain from viruses, bacteria and toxins. We clearly demonstrate that listening to loud music during 2 h in an intermittent adaptive regime is accompanied by delayed (1 h after music exposure) and short-lasting to (during 1–4 h) OBBB to low and high molecular weight compounds without cochlear and brain impairments. We present the systemic and molecular mechanisms responsible for music-induced OBBB. Finally, a revision of our traditional knowledge about the BBB nature and the novel strategies in optimizing of sound-mediated methods for brain drug delivery are discussed.     

Plant virus infection development as affected by heavy metal stress

The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants.     

Late Triassic radiolarians of southern Cyprus

Radiolarians from the Upper Triassic of the allochthonous Mamonia Assemblage of southern Cyprus are considered. The Phasoula Formation, composed of basic volcanics, with lenses and interbeds of micritic limestones and cherts, contains (1) a Lower Norian assemblage with Capnodoce crystallina-Trialatus robustus, which also includes Capnodoce anapetes De Wever, Capnuchosphaera deweveri Kozur et Mostler, C. theloides De Wever, Deflandrecyrtium curvatum Kozur et Mostler, Icrioma cruciformis Tekin, Kahlerosphaera norica Kozur et Mock, Kinyrosphaera helicata Bragin, Mostlericyrtium sitepesiformis Tekin, Palaeosaturnalis latiannulatus Kozur et Mostler, Spongostylus tortilis Kozur et Mostler, Xiphotheca rugosa Bragin, and Zhamojdasphaera proceruspinosa Lahm; (2) a Middle Norian assemblage with Capnodoce sarisa accompanied by Loffa mulleri Pessagno, Nabolella trispinosa Bragin, and Praexehasaturnalis tenuispinosus (Donofrio et Mostler); and (3) an Upper Norian assemblage with Livarella densiporata-Lysemelas olbia accompanied by Pentactinocarpus sevaticus Kozur et Mostler, Praemesosaturnalis multidentatus (Kozur et Mostler), and others. This assemblage also occurs in clastic turbidites of the Vlambouros Formation. In the sections of southern Cyprus, radiolarian zones are recognized that correspond to the zones previously established in the Far East of Russia, which include Capnodoce crystallina (Lower and Middle Norian) and Lysemelas olbia (lower part of the Upper Norian). Radiolarians belonging to three orders, 24 families, 59 genera, and 101 species are described; of them 2 genera, 9 species, and 1 subspecies were previously described by the author; 14 new species and 1 new subspecies are established. The diagnoses of many genera and species are emended, the stratigraphic and geographical ranges of the majority of taxa are substantially expanded.     

Neuronal septal activity during hippocampal seizure discharges generation in acute model of epilepsy

The activity of the neurones of the medial septal region (MS) and the hippocampal EEG in control and during the appearance of seizure discharges provoked by electrical stimulation of the perforant path were investigated in the awake rabbit. During afterdischarge generation in the hippocampus the dense neuronal bursts separated by periods of inhibition were recorded in the MS. In one group of neurons the bursts of spikes coincided with the discharges in the hippocampus, in other group-occured during inhibitory periods. When the afterdischarge stopped, in the septal neurons with theta activity the disruption of theta pattern was recorded, which have been correlated with the occurrence of low amplitude high frequency (20-25 Hz) waves in the hippocampal EEG. As a rule, the neuronal activivity of the MS recovered much quickly than EEG of the hippocampus; in some cases the increasing of the theta regularity was observed. The definite accordance of the electrical activity of the hippocampus and MS during seizure discharges suggests that the septohippocampal system operate as integral nervous circuit in these conditions. Diverse in the temporal interrelations between the discharges of MS neurones and ictal discharges in the hippocampus in the different cells possible indicate that various groups of the septal nervous elements have different participation in the seizure development. Appearance of the high frequency bursts in the MS is a possible "precursor" of the seizure onsets.     

Using naturally shed feathers for individual identification, genetic parentage analyses, and population monitoring in an endangered Eastern imperial eagle (Aquila heliaca) population from Kazakhstan

Genetic analyses on noninvasively collected samples have revolutionized how populations are monitored. Most noninvasive monitoring studies have used hair or scat for individual identification of elusive mammals, but here we utilize naturally shed feathers. The Eastern imperial eagle (EIE) is a species of conservation concern throughout Central Asia and, like most raptors, EIEs are inherently challenging to study because adults are difficult to capture and band using conventional techniques. Over 6 years, we noninvasively collected hundreds of adult feathers and directly sampled EIE chicks at a national nature reserve in Kazakhstan. All samples were genetically sexed and genotyped at a suite of microsatellite loci. Genetically profiled adult feathers identified and monitored the presence of individual eagles over time, enabling us to address a variety of issues related to the biology, demography, and conservation of EIEs. Specifically, we characterized (i) the genetic mating system, (ii) relatedness among mated pairs, (iii) chick sex ratios, and (iv) annual turnover in an adult breeding population. We show that EIEs are genetically monogamous and furthermore, there is no apparent relatedness-based system of mate choice (e.g. inbreeding avoidance). Results indicate that annual adult EIE survivorship (84%) is lower than expected for a long-lived raptor, but initial analyses suggest the current reproductive rate at our study site is sufficient to maintain a stable breeding population. The pristine habitat at our study site supports an EIE population that is probably the most demographically robust in the world; thus, our results caution that populations in marginal habitats may not be self-sustaining.     

Spectral and functional properties of ceruloplasmin under UV irradiation

During oxydase reaction spectral characteristics of ceruloplasmin at absorption of copper ions and protein part of the molecule are shown to change. It has been ascertained, that when irradiating ceruloplasmin by UV-light the functioning of intramolecular electron transport chain is broken, the degree of positive cooperativity (a Hill's constant) on substrate decreases. It is supposed, that these changes are caused by disturbance of interdomain interactions in a protein molecule.