Nucleic acid and protein content of cells of the raphe nuclei of the rat brain when the animals are deprived of the paradoxical sleep phase

A 24 hours paradoxical sleep deprivation (PSD) with rats resulted in lowering the RNA content in neurons and gliocytes of n. raphé dorsalis by 31 and 18%, resp.; the protein content remaining unchanged. A 48 hours PSD reduced RNA and protein contents in neurons by 31%; in gliocytes both these substances being on the control level. In the neurons of n. raphé pontis, by the end of the 1st day of PSD the contents of both RNA and protein were seen reduced by 16 and 28%, resp.; however, by the end of the 2nd day their levels well compared with those in the control rats. There was a phase oscillation of protein content in gliocytes: from - 19%, on the first day of PSD, to +19%, on the 2nd day. There is a great resemblance in response to PSD between the adrenergic nucleus - locus coeruleus - and n. raphé pontis, whereas their responses differ from that of the serotoninergic n. raphé dorsalis.     

Influence of Synchronized Sleep on the Biosynthesis of RNA in Two Nuclear Classes Isolated from Rabbit Cerebral Cortex

The biosynthesis of RNA during sleep has been studied in two purified nuclear fractions, separated from rabbit cerebral cortex after subarachnoidal injection of radioactive orotate. The biochemical parameters have been referred to the percent EEG synchronization recorded during the period of incorporation (1 hr). The content of radioactive RNA per nucleus increases significantly with percent synchronization in the fraction of large nuclei (of neuronal and astroglial origin). While sedimentation and electrophoretic analyses of this RNA are consistent with the hypothesis of an enhanced turnover of rRNA during wakefulness, the accumulation of labelled RNA which is observed during sleep may be due to a modified turnover of nuclear heterogeneous RNA. On the other hand, in the fraction of small nuclei (mostly of oligodendroglial origin) the content of radioactive RNA per nucleus and the pattern of sedimentation of labelled RNA show no dependence on the electrical state of the cortex. These data indicate that in the cerebral cortex the sleep-wakefulness transition is accompanied by a different cellular response in RNA turnover.     

Expression of aquaporin-4 water channels in the digestive tract of the guinea pig

Expression of the aquaporin-4 (AQP4) water channel was systematically studied in the digestive tract of the guinea pig using Western blot and immunofluorescence techniques. The results showed that AQP4 was expressed widely in different segments of the guinea pig digestive tract. AQP4-immunoreactivity was confined to parietal cells in the stomach, and absorptive and glandular epithelial cells of small and large intestine. AQP4 protein was also expressed by enteric glial cells of submucosal and myenteric ganglia and primary nerve trunks. AQP4 was expressed by both type I and type II enteric gliocytes, but not by type III or type IV enteric gliocytes, indicating that enteric gliocytes have a heterogeneous distribution in the gut wall. In addition, different patterns of AQP4 expression in the enteric nervous system of human, guinea pig, rat and mouse colon mucosa were identified: in rat and mouse AQP4 was localised to a small subpopulation of neurons; in the guinea pig AQP4 was localised to enteric glial cells; and in the human colon mucosa, AQP4 was also detected mainly in the glial cells. It has been speculated that AQP4 may be involved in water transport in the gastrointestinal tract. Its role in enteric neurons and glia is unknown, but, by analogy with the brain, AQP4 may be involved in the formation and resolution of edema.     

A comparative study of the effect of RNA and DNA treatment on somatic nuclei in plant cells

Summary The effect of different concentrations of ribonucleic acid (RNA) and desoxyribonucleic acid (DNA) has been studied on meristematic somatic cells ofAllium cepa. The principal effects noted with both are polyploidy and reductional separation of chromosomes.It has been assumed that RNA causes viscosity change in the plasma, which is responsible for polyploidy. DNA, though entering in a minute quantity due to its high molecular weight, gets ultimately converted into RNA precursors and finally causes the same effect. Somatic reduction is caused by an increase in the DNA content of the plasma and as such, application of this chemical causes reductional separation of chromosomes. RNA, on the other hand, needs gradual conversion into DNA precursors to cause the effect. The concurrent nature of the two processes allows the simultaneous occurrence of polyploidy and somatic reduction after a brief interval following artificial treatment.With 8 Figures in the Text     

Ultrastructure of the pacemaker cells of the sinoatrial node in rats

Ultrastructure of the cells generating the action potential, specific for the pacemaker of the sinuous-auricular node has been studied. The cells are labelled with lanthanum chloride by means of the registrating microelectrode. Two types of pacemakers are revealed. The cells of one type contain specific auricular granules, while those of the other type do not contain them. The pacemaker-cells of the sinuous-auricular node have some peculiarities in the structure of the contractile apparatus, mitochondria, Golgi complex, intercellular contacts owing to which their morphological identification is possible.     

Changes in the neurite-glial interrelations under the influence of antiserum against galactocerebrosides (a vital tissue culture study)

Two--five-day-old culture of 10-11-day-old chick embryos has been used. Antiserum against galactocerebrosides (anti-GalC) is added to the nutrition medium before cultuvation. In the presence of anti-GalC the growth and gliocyte migration zone decreases, the area index becomes essentially small (3.5 +/- 0.7 in the control, 1.5 +/- 0.5 in the experiment). This is connected with inhibition of migration and proliferation of gliocytes during first 48 h of cultivation, while intensity of neuron regeneration remains unchanged. Alterations of the neurit-glial relations are investigated by means of the vital phase-contrast microscopy. Effect of anti-GalC to peripheral gliocytes is accompanied with a decreasing adhesive ability of their plasmolemma. This makes difficult their flattening on the neurit membrane, formation of contact membranous neurit-glial relations and formation of glial membranes. On the 3d day formation of nervous fasciculi is retarded, as well as their fusion into trunks and plexuses. On the 5th day, unlike the control, a continuous "epineural" covering of neuritic plexuses does not form. Round retractile and defective (with protrusions) forms of gliocytes predominate. These data demonstrate inhibitory effect of anti-GalC on the structural-functional maturation of the glia and on formation of neurit-glial relations in the culture of the sensitive ganglion.     

Effect of LNA- and OMeN-modified oligonucleotide probes on the stability and discrimination of mismatched base pairs of duplexes

Locked nucleic acid (LNA) and 2'-O-methyl nucleotide (OMeN) are the most extensively studied nucleotide analogues. Although both LNA and OMeN are characterized by the C3'-endo sugar pucker conformation, which is dominant in A-form DNA and RNA nucleotides, they demonstrate different binding behaviours. Previous studies have focused attention on their properties of duplex stabilities, hybridization kinetics and resistance against nuclease digestion; however, their ability to discriminate mismatched hybridizations has been explored much less. In this study, LNA- and OMeN-modified oligonucleotide probes have been prepared and their effects on the DNA duplex stability have been examined: LNA modifications can enhance the duplex stability, whereas OMeN modifications reduce the duplex stability. Next, we studied how the LNA:DNA and OMeN:DNA mismatches reduced the duplex stability. Melting temperature measurement showed that different LNA:DNA or OMeN:DNA mismatches indeed influence the duplex stability differently. LNA purines can discriminate LNA:DNA mismatches more effectively than LNA pyrimidines as well as DNA nucleotides. Furthermore, we designed five LNA- and five OMeN-modified oligonucleotide probes to simulate realistic situations where target-probe duplexes contain a complementary LNA:DNA or OMeN:DNA base pairs and a DNA:DNA mismatch simultaneously. The measured collective effect showed that the duplex stability was enhanced by the complementary LNA:DNA base pair but decreased by the DNA:DNA mismatch in a position-dependent manner regardless of the chemical identity and position of the complementary LNA:DNA base pair. On the other hand, the OMeN-modified probes also showed that the duplex stability was reduced by both the OMeN modification and the OMeN:DNA mismatch in a position-dependent manner.     

Morphological reactions of neural elements in the limbic region of the cerebral cortex to whole body roentgen irradiation

After whole-body X-irradiation with a dose of 5 Gy, the content of limbic neocortex cells of altered neurocytes markedly increases: many of the disorders in their structure are reversible. In the inner cell complex the neurocytes with "dark type" changes are frequent and, in most cases, irreversible. Different types of gliocytes respond in a different manner to the effect of ionizing radiation.     

Neurono-glial ratios in the frontal cortex of the human cerebrum in normal and pathologic aging (Alzheimer's disease)

Structural organization of the frontal area cortex (fields 8 and 47) in the left and right cerebral hemispheres has been studied cytoarchitectonically in mentally sound and sick persons of various age groups (34-40, 50-60 and 80-90 years). In sections 20 mcm thick, stained with cresyl-violet, in 0.001 mm3 of the cerebral substance (layers III and V) arrangement density is estimated for all pyramidal neurons, for all gliocytes, neurons surrounded with satellite glia and separately for perineuronal gliocytes, as well as per cent ratio of all the parameters obtained. In the process of normal and pathological ageing certain changes, both common for these two processes and specific for each of them, take place in the structural organization of the fields 8 and 47. Under normal ageing the changes are more distinct in the field 8, in the layer III, and at Alzheimer's disease there is a slight prevalence of them in the associative field 47, in the layer V.     

COMPOSITION OF RIBONUCLEIC ACID FROM VARIOUS PARTS OF SPIDER OOCYTES

Microphoretic purine-pyrimidine analyses of the ribonucleic acid (RNA) in nucleoli, nucleoplasm, cytoplasm, and yolk nuclei of spider oocytes have been carried out. The material necessary for the analyses was isolated by micromanipulation. Determinations of the amounts of RNA in the different parts of the cell were also performed. No differences between the composition of RNA in the nucleolus and the cytoplasm could be disclosed. Nucleoplasmic RNA was, on the other hand, distinctly different from that in the nucleolus and in the cytoplasm. The difference lies in the content of adenine, which is highest in nucleoplasmic RNA. The few analyses carried out on yolk nuclei showed their RNA to be variable in composition with a tendency to high purine values. The cytoplasm contains about 99 per cent of the total RNA in these cells, the nucleoplasm about 1 per cent, and the nucleolus not more than 0.3 per cent, although the highest concentrations are found in these latter structures. When considered in the light of other recent findings the results are compatible with the view that nucleolar RNA is the precursor of cytoplasmic RNA.     

我国玉米自交系茎秆性状多样性分析

研究我国玉米自交系茎秆性状特征及其多样性,是培育宜机收玉米品种的重要前提。本研究以兰卡斯特、PB、四平头、旅大红骨和瑞德五大主要类群70份主要玉米自交系为材料,调查12个茎秆相关性状(茎高、穗位高、穗位系数、茎节数、穗位节、穗节系数、穗茎长、穗茎粗、茎鲜重、茎干重、含糖量和含水量),分析性状相关性和类群多样性。结果表明,我国地方种质四平头和旅大红骨茎秆性状表型变异丰富;灌浆期玉米茎秆含水量比较稳定;玉米植株高度与茎节长度显著相关;玉米雌、雄穗节之间的节间数比较恒定;玉米茎秆含糖量与茎节长度、茎粗、果穗着生位置有关;有效降低穗位高度应从降低果穗着生节入手;类群茎秆特征鲜明:兰卡斯特茎节较少,瑞德茎秆较粗,PB茎秆较细,旅大红骨茎秆较粗、茎节较短,四平头植株较矮、茎秆含糖量较低、干物质含量较低;兰卡斯特×四平头和兰卡斯特×PB类群间存在较强的生物量及籽粒产量杂种优势;挖掘和利用茎节较长、穗位较低的玉米地方种质是我国宜机收玉米育种的技术途径。本研究结果对玉米育种具有重要指导意义。     

Cell proliferation and migration in the roof of the mesencephalon (tectum) in Xenopus laevis tadpoles and adult frogs normally and in brain injury. II. Cell proliferation and differentiation of the tectum in frogs]

The proliferation and directions of cell differentiation in tectum opticum were studied in the young frogs under the conditions of normal development and upon brain trauma by means of 3H-thymidine autoradiography. The same types of cells were shown to be able of proliferation in both the cases: cells of the ventricle zone and glioblasts (gliocytes) in all other tectum layers. A study of directions of the tectum proliferating cells' differentiation in the frogs has shown that the proliferating cells differentiate mainly in the ependyme tanicytes in the ventricle layer 1 and gliocytes in the other tectum layers. The trauma did not change the direction of proliferating cells' differentiation towards the formation of neurons. The complete regeneration is observed in the tectum layer 1 only.     

Involvement of RNA and DNA in the staining of Escherichia coli by SYTO 13

AIMS: To assess the extent to which DNA and RNA bacterial content contributes to fluorescent response of SYTO 13. METHODS AND RESULTS: RNA and DNA of Escherichia coli 536 cells were extracted and fluorimetrically quantified to compare the different contents, throughout a 24 h culture, with their SYTO 13 fluorescence emission when analysed by the cytometer. SYTO 13 fluorescence varied depending on the stage of bacterial growth and in accordance with both DNA and RNA content. RNA content accounted for at least two-thirds of the total fluorescence of a cell. Escherichia coli cells were treated with chloramphenicol to improve their RNA content. With this treatment, both nucleic acids remained constant but there was a clear improvement in fluorescent emission. SYTO 13 fluorescence was also studied in E. coli X-1488 minicells. CONCLUSIONS: Although both nucleic acids are implicated, RNA accounts for a major part of SYTO 13 fluorescence. The fluorescence cannot be considered as a direct reflection of nucleic acid content. Other factors, such as topology or supercoiling, need to be considered. SIGNIFICANCE AND IMPACT OF THE STUDY: The results confirm the efficacy of SYTO 13 for labelling bacteria and for assessing the distinct physiological status. A better knowledge of the parameters implicated in its fluorescence emission has been achieved.     

The devil in the details: interactions between the branch-length prior and likelihood model affect node support and branch lengths in the phylogeny of the Psoraceae

In popular use of Bayesian phylogenetics, a default branch-length prior is almost universally applied without knowing how a different prior would have affected the outcome. We performed Bayesian and maximum likelihood (ML) inference of phylogeny based on empirical nucleotide sequence data from a family of lichenized ascomycetes, the Psoraceae, the morphological delimitation of which has been controversial. We specifically assessed the influence of the combination of Bayesian branch-length prior and likelihood model on the properties of the Markov chain Monte Carlo tree sample, including node support, branch lengths, and taxon stability. Data included two regions of the mitochondrial ribosomal RNA gene, the internal transcribed spacer region of the nuclear ribosomal RNA gene, and the protein-coding largest subunit of RNA polymerase II. Data partitioning was performed using Bayes' factors, whereas the best-fitting model of each partition was selected using the Bayesian information criterion (BIC). Given the data and model, short Bayesian branch-length priors generate higher numbers of strongly supported nodes as well as short and topologically similar trees sampled from parts of tree space that are largely unexplored by the ML bootstrap. Long branch-length priors generate fewer strongly supported nodes and longer and more dissimilar trees that are sampled mostly from inside the range of tree space sampled by the ML bootstrap. Priors near the ML distribution of branch lengths generate the best marginal likelihood and the highest frequency of "rogue" (unstable) taxa. The branch-length prior was shown to interact with the likelihood model. Trees inferred under complex partitioned models are more affected by the stretching effect of the branch-length prior. Fewer nodes are strongly supported under a complex model given the same branch-length prior. Irrespective of model, internal branches make up a larger proportion of total tree length under the shortest branch-length priors compared with longer priors. Relative effects on branch lengths caused by the branch-length prior can be problematic to downstream phylogenetic comparative methods making use of the branch lengths. Furthermore, given the same branch-length prior, trees are on average more dissimilar under a simple unpartitioned model compared with a more complex partitioned models. The distribution of ML branch lengths was shown to better fit a gamma or Pareto distribution than an exponential one. Model adequacy tests indicate that the best-fitting model selected by the BIC is insufficient for describing data patterns in 5 of 8 partitions. More general substitution models are required to explain the data in three of these partitions, one of which also requires nonstationarity. The two mitochondrial ribosomal RNA gene partitions need heterotachous models. We found no significant correlations between, on the one hand, the amount of ambiguous data or the smallest branch-length distance to another taxon and, on the other hand, the topological stability of individual taxa. Integrating over several exponentially distributed means under the best-fitting model, node support for the family Psoraceae, including Psora, Protoblastenia, and the Micarea sylvicola group, is approximately 0.96. Support for the genus Psora is distinctly lower, but we found no evidence to contradict the current classification.     

Morphometric characteristics of neuron-glial relations in brain edema caused by stimulation of hypothalamic nuclei

Morphologic characteristics and certain changes in cell composition of the cortex and the white substance of the brain have been studied at experimentally produced brain edema by stimulation of the lateral hypothalamic field, the indefinite zone, Forel's fields H1 and H2. It has been stated that diffuse edema of the white substance and perivascular edema dominate in histopathological changes. Morphometrical analysis of the structural changes had demonstrated a certain increase in the cortex thickness, decreased density in the arrangement of the neurons and increased volume of their nuclei at more moderate enlargement of their body volumes, as well as increased volume of the nuclei in the cortical glial cells and the white substance cells. In the cortex cells is observed, that is accompanied with increased glial index and average number of perineuronal gliocytes per one neuron. Simultaneously, in both hemispheres, the character in the arrangement of the perineuronal glia as regards the neuron changes. At the same time, in the white substance, the density of the glial arrangement sharply decreases. The changes have demonstrated that wider perivascular spaces predominate in small vessels. All the changes mentioned are more pronounced in the contralateral hemisphere.     

Effects of osmolytes on RNA secondary and tertiary structure stabilities and RNA-Mg2+ interactions

Osmolytes are small organic molecules accumulated by cells in response to osmotic stress. Although their effects on protein stability have been studied, there has been no systematic documentation of their influence on RNA. Here, the effects of nine osmolytes on the secondary and tertiary structure stabilities of six RNA structures of differing complexity and stability have been surveyed. Using thermal melting analysis, m-values (change in ΔG° of RNA folding per molal concentration of osmolyte) have been measured. All the osmolytes destabilize RNA secondary structure, although to different extents, probably because they favor solubilization of base surfaces. Osmolyte effects on tertiary structure, however, can be either stabilizing or destabilizing. We hypothesize that the stabilizing osmolytes have unfavorable interactions with the RNA backbone, which becomes less accessible to solvent in most tertiary structures. Finally, it was found that as a larger fraction of the negative charge of an RNA tertiary structure is neutralized by hydrated Mg²⁺, the RNA becomes less responsive to stabilizing osmolytes and may even be destabilized. The natural selection of osmolytes as protective agents must have been influenced by their effects on the stabilities of functional RNA structures, though in general, the effects of osmolytes on RNA and protein stabilities do not parallel each other. Our results also suggest that some osmolytes can be useful tools for studying intrinsically unstable RNA folds and assessing the mechanisms of Mg²⁺-induced RNA stabilization.     

Inhibition of viral protein synthesis in monkey cells treated with interferon late in simian virus 40 lytic cycle.

We have investigated the effect of interferon on SV40 gene expression late in the lytic cycle, after early functions have been expressed and viral DNA replication has been initiated. Whereas pretreatment with interferon prior to infection reduces the amount of early SV40 RNA, post-infection treatment does not inhibit viral RNA synthesis. Viral 19S and 16S RNA species are found undiminished in quantity and poly(A) content. Despite the apparent normalcy of viral RNA classes, however, there is a marked reduction in the synthesis of their protein products, both T antigen and capsid polypeptides. The association of viral RNA with heavy polyribosomes is strongly reduced. On the other hand, there is no degradation of nonviral polyribosomes and the synthesis of most cellular proteins continues. These experiments demonstrate that late in infection, interferon treatment results in an inhibition of viral mRNA translation.