Significance of Individual Features in Interpreting the Indices of Spectral Components of the Cardiac Rhythm

The authors evaluated the significance of individual properties (extroversion and individual anxiety) in the analysis of cardiorhythmograms. The subjects demonstrated significant correlations between the spectral characteristics of cardiac rhythm and extroversion and individual anxiety levels. The correlation between the spectral characteristics of the cardiac rhythm and extroversion significantly strengthened when the individual anxiety level was taken into account and vice versa. Cardiorhythmograms differed significantly in extroverts and introverts with increased and normal levels of individual anxiety.     

Genetic and Demographic Structure of the Yakut Population: Reproduction Indices

Genetic and demographic information for the Yakut population living in the Republic of Sakha (Yakutia) is presented. The mean number of children per woman constituted 4.605. Crow's index (I _tot) and its components (I _m and I _f) were 0.483, 0.104, and 0.343, respectively.     

半纤维素结构的植物分类学特征

依据结构特征界定了半纤维素。不同植物品种和不同细胞类型的半纤维素在结构细节和含量上普遍存在着差异。总结了从轮藻到陆生植物中的半纤维素在结构上的分类学分布,并据此比较了初生壁和次生壁。     

Light-Harvesting Features Revealed by the Structure of Plant Photosystem I

Oxygenic photosynthesis is driven by two multi-subunit membrane protein complexes, Photosystem I and Photosystem II. In plants and green algae, both complexes are composed of two moieties: a reaction center (RC), where light-induced charge translocation occurs, and a peripheral antenna that absorbs light and funnels its energy to the reaction center. The peripheral antenna of PS I (LHC I) is composed of four gene products (Lhca 1-4) that are unique among the chlorophyll a/b binding proteins in their pronounced long-wavelength absorbance and in their assembly into dimers. The recently determined structure of plant Photosystem I provides the first relatively high-resolution structural model of a super-complex containing a reaction center and its peripheral antenna. We describe some of the structural features responsible for the unique properties of LHC I and discuss the advantages of the particular LHC I dimerization mode over monomeric or trimeric forms. In addition, we delineate some of the interactions between the peripheral antenna and the reaction center and discuss how they serve the purpose of dynamically altering the composition of LHC I in response to environmental pressure. Combining structural insight with spectroscopic data, we propose how altering LHC I composition may protect PS I from excessive light.     

Energetics of MazG Unfolding in Correlation with Its Structural Features

MazG is a homodimeric α-helical protein that belongs to the superfamily of all-α NTP pyrophosphatases. Its function has been connected to the regulation of the toxin-antitoxin module mazEF, implicated in programmed growth arrest/cell death of Escherichia coli cells under conditions of amino acid starvation. The goal of the first detailed biophysical study of a member of the all-α NTP pyrophosphatase superfamily, presented here, is to improve molecular understanding of the unfolding of this type of proteins. Thermal unfolding of MazG monitored by differential scanning calorimetry, circular dichroism spectroscopy, and fluorimetry at neutral pH in the presence of a reducing agent (dithiothreitol) can be successfully described as a reversible four-state transition between a dimeric native state, two dimeric intermediate states, and a monomeric denatured state. The first intermediate state appears to have a structure similar to that of the native state while the final thermally denatured monomeric state is not fully unfolded and contains a significant fraction of residual α-helical structure. In the absence of dithiothreitol, disulfide cross-linking causes misfolding of MazG that appears to be responsible for the formation of multimeric aggregates. MazG is most stable at pH 7-8, while at pH < 6, it exists in a molten-globule-like state. The thermodynamic parameters characterizing each step of MazG denaturation transition obtained by global fitting of the four-state model to differential scanning calorimetry, circular dichroism, and fluorimetry temperature profiles are in agreement with the observed structural characteristics of the MazG conformational states and their assumed functional role.     

Special Features of the Three-Dimensional Structure Defining Properties of Aspartic Proteases

A brief account is given of the specific interactions of some amino acid residues in aspartic proteases of both higher organisms and retroviruses that determine important protease properties: the anomalously low isoelectric point of pepsin and its stability at pH close to 1; the ability of one of the carboxyl groups in the active site of proteases of higher organisms to retain a charged state at any pH value; and the protonated state of another carboxyl, which is necessary for enzymatic activity. It is also explained how such states can be induced in retroviral proteases.     

Reflection of the Intelligence Structure in the Spatiotemporal Features of the Baseline EEG

The EEG correlates of the verbal, numerical, and figural IQ components according to the power and coherence characteristics of the baseline EEG in six frequency bands were studied taking into account personality traits of subjects (extroversion, neuroticism, psychoticism, and anxiety). Analysis of variance and correlation showed that a decreased power of the low-frequency _{1, 2}and ₁ rhythms and increased EEG power in the ₂ band with the right-hemispheric dominance were characteristic of persons with higher intelligence. These EEG characteristics were associated with increased interhemispheric interaction according to the coherence indices and increased coherence within the right hemisphere. Each of the intelligence components (verbal, numerical, and figural) was characterized by a specific baseline frequency–spatial EEG pattern distinguished by specific interactions, predominantly, between the frontal and caudal cortical regions in the and/or ₂ frequency bands.     

Correlation of Computed Tomography with Pathological Features in Angiomatous Nasal Polyps

Background

Angiomatous nasal polyps (ANPs), also known as angiectatic polyps, have rarely been reported in the literature. ANPs are characterized by extensive vascular proliferation and ectasia. ANPs can grow rapidly and exhibit aggressive clinical behavior that could simulate malignancy preoperatively, and they are easily confused with other diseases. In the present study, we analyzed the correlation between the computed tomography (CT) findings of nasal angiomatous polyps and their pathological features.

Methods

We evaluated CT findings and pathological features of 31 surgically proven ANPs.

Results

The study population included 16 males and 15 females aged between 27 and 81 years (mean age, 53.5 years). On CT, the masses were heterogeneous; they had a soft tissue density and filled the maxillary and/or nasal cavities. Calcifications were found in 2 of the 31 cases. The lesions showed a clear boundary (15/31). The low-density shading on CT was related to the inflammatory, necrotic, and cystic changes, and the high-density shading on CT was related to hemorrhagic areas of the mass. On contrast-enhanced CT, the center of the lesions was non-enhanced with peripheral intensification due to occlusion or compression of feeder vessels of the polyp center, and the inflammatory cells and neovascularization around the edge of the mass. The most common site of maxillary wall erosion was the medial wall (21/31), followed by the posterior lateral wall (3/31), upper wall (2/31), and septum (3/31). Of these, the nasal cavity and/or maxillary sinus were enlarged in 28 cases. These findings were associated with the chronic progress of nasal angiomatous changes.

Conclusions

CT of ANPs may demonstrate benign bone changes associated with the lesions and may also reflect the fact that ANPs do not invade peripheral soft tissue. CT demonstrated these lesions consistently and provided information useful for surgical planning.     

Correlation between CAG Repeat Length and Clinical Features in Machado-Joseph Disease

Machado-Joseph disease (MJD) is associated with the expansion of a CAG trinucleotide repeat in a novel gene on 14q32.1. We confirmed the presence of this expansion in 156 MJD patients from 33 families of different geographic origins: 15 Portuguese Azorean, 2 Brazilian, and 16 North American of Portuguese Azorean descent. Normal chromosomes contain between 12 and 37 CAG repeats in the MJD gene, whereas MJD gene carriers have alleles within the expanded range of 62–84 CAG units. The distribution of expanded alleles and the gap between normal and expanded allele sizes is either inconsistent with a premutation hypothesis or most (if not all) of the alleles we studied descend from a common ancestor. There is a strong correlation between the expanded repeat size and the age at onset of the disease as well as the clinical presentation. There is mild instability of the CAG tract length with transmission of the expanded alleles; both increase and decrease in size between parents and progeny occur, with larger variations in male than in female transmissions. Together, these effects can partly explain the variability of age at onset and of phenotypic features in MJD; however, other modifying factors must exist.     

Correlation of Rhs Elements with Escherichia Coli Population Structure

The Rhs family of composite genetic elements was assessed for variation among independent Escherichia coli strains of the ECOR reference collection. The location and content of the RhsA-B-C-F subfamily correlates highly with the clonal structure of the ECOR collection. This correlation exists at several levels: the presence of Rhs core homology in the strain, the location of the Rhs elements present, and the identity of the Rhs core-extensions associated with each element. A provocative finding was that an identical 1518-bp segment, covering core-extension-b1 and its associated downstream open reading frame, is present in two distinct clonal groups, but in association with different Rhs elements. The sequence identity of this segment when contrasted with the divergence of other chromosomal segments suggests that shuffling of Rhs core extensions has been a relatively recent variation. Nevertheless the copies of core-extension-b1 were placed within the respective Rhs elements before the emergence of the clonal groups. In the course of this analysis, two new Rhs elements absent from E. coli K-12 were discovered: RhsF, a fourth member of the RhsA-B-C-F subfamily, and RhsG, the prototype of a third Rhs subfamily.