Single‐nucleotide Polymorphism of CD36 Locus and Obesity in European Adolescents

CD36 is a membrane receptor with a wide variety of functions, including the regulation of energy metabolism, fat storage, and adipocyte differentiation. To assess the relationship between CD36 gene single‐nucleotide polymorphisms (SNPs) and obesity in adolescents, we evaluated the relationship between CD36 SNPs and the risk of obesity in a case–control study composed of 307 obese (age = 15.0 ± 1.1 years) and 339 normal‐weight adolescents (age = 14.6 ± 1.1 years). To validate the results, we assessed the relation between the same SNPs and percentage of body fat (BF%) and BMI in 1,151 European adolescents (age = 14.8 ± 1.4 years). SNPs with a minor allele frequency >0.10 were selected to tag CD36. Genotyping was performed on an Illumina system. Four SNPs (rs3211867, rs3211883, rs3211908, and rs1527483) were associated with increased risk of obesity in the case–control study (odds ratio (OR) (95% confidence interval)): 1.96 (1.26–3.04], P = 0.003; 1.73 (1.16–2.59), P = 0.007; 2.42 (1.47–4.01), P = 0.0005 and 1.95 (1.25–3.05), P = 0.003, respectively). The same four SNPs were associated with higher BMI (P < 0.05) and BF% (P < 0.04) in the validation study. Further analyses identified a haplotype (frequency: 0.05) carrying the minor allele of these SNPs as being associated with obesity (OR: 2.28; P = 0.0008) in the case–control study and with excess adiposity (i.e., higher BF% (P = 0.03) and BMI (P = 0.04)) in the validation study. Our data suggest that genetic variability at the CD36 gene locus could be associated with body weight variability in European adolescents but these findings require replication.     

The structure and function of frataxin

Frataxin, a highly conserved protein found in prokaryotes and eukaryotes, is required for efficient regulation of cellular iron homeostasis. Humans with a frataxin deficiency have the cardio- and neurodegenerative disorder Friedreich's ataxia, commonly resulting from a GAA trinucleotide repeat expansion in the frataxin gene. While frataxin's specific function remains a point of controversy, the general consensus is that the protein assists in controlling cellular iron homeostasis by directly binding iron. This review focuses on the structural and biochemical aspects of iron binding by the frataxin orthologs and outlines molecular attributes that may help explain the protein's role in different cellular pathways.     

Cytotoxicity of water extracts from leaves and branches of Philadelphus coronarius L

Philadelphus coronarius L. is big, leggy and deciduous old-fashioned shrub known for its fragrant white flowers in the late spring. Some members of genus Philadelphus L. are known for their antibacterial, antiradical and immunomodulatory effects. Therefore, these herbs represent prospective sources for the isolation of active substances with desired effects. We have investigated the cytotoxicity effects of water extracts from leaves and branches of Philadelphus coronarius L. (Hydrangeaceae). A431 cells (human skin carcinoma cell line) and the human breast adenocarcinoma cell line (MCF-7) were treated with various doses of individual extracts (0,1-100 microg dry matter/ml) for 24 h and 72 h. The highest toxic effects of both plant parts extracts were observed on MCF-7 cells regardless the time of treatment. Cells A431 were less sensitive to toxic effects of leaves and branches extracts but the time dependence was present with the tendency of increased toxicity after chronic treatment. There were no differences in the extent of toxic effects between branches and leaves extracts. The results obtained so far will provide the basis for the future studies with isolated active substances from these extracts.     

The p32K Structural Protein of the Atadenovirus Might Have Bacterial Relatives

Abstract The primary structure of a novel adenoviral protein referred to as p32K and found exclusively in members of the proposed new genus Atadenovirus was analyzed. The p32K gene sequence was determined from two bovine and one snake adenovirus types. Altogether five different p32K sequences were examined, two of them were obtained from the Gene Bank. The C-terminal part of the protein is conserved and shares similarity with certain bacterial small acid soluble proteins (SASPs). The sequence similarity seems coupled with functional relatedness, i.e. both protein groups are found in structures where the genome of the “dormant” organism is packaged in tight nucleoprotein complexes. In these complexes the DNA is protected against harmful environmental effects until the new reproductive cycle is started with specific protease cleavage of the packaging proteins. Although there is no experimental clue about the role of the p32K proteins, we hypothesize phylogenetic relationship between the two protein groups based on the sequence similarity and the supposed functional similarity. The alignments of these protein groups shows that the conserved part of the p32Ks probably is the result of the duplication of a shorter sequence similar to the SASPs of the Bacilli.     

The location of 5S RNA genes in lampbrush polytene chromosomes from Drosophila

Drosophila polytene chromosomes were transformed into lampbrush-like structures by exposure to solutions of alkali-urea. In this process, the chromosomes shorten and widen, and the bands (chromomeres) extend laterally into loops leaving a central core between the paired homologues. The expanded polytene chromosomes are very similar in appearance to the true lampbrush chromosomes of amphibian oocytes and to ordinary chromosomes in pachytene. The denaturing effects of alkali-urea were partially counteracted by return of the treated chromosomes to Ringer solution. These observations are interpreted in terms of recent findings on protein backbones in chromosomes, and indicate that chromosomes generally may have very similar basic organization, despite differences due to species, polyteny and degree of condensation. To gain more information on the specific location of a structural gene, ¹²⁵I-labelled low molecular weight (containing 5S RNA) was hybridized in situ to normal and lampbrush-like polytene chromosomes. Autoradiography showed silver grain distribution for 5S RNA consistent with hybridization primarily to the loop regions of the lampbrush chromosomes rather than the core. This provides further indirect evidence that structural genes like 5S RNA may be located on the bands (chromomeres) and not the interbands of normal polytene chromosomes.     

Isolation and characterization of X-linked lethal mutants affecting differentiation of the imaginal discs in Drosophila melanogaster

Summary Twenty-seven late larval or early pupal lethal mutations were isolated for the X-chromosome, some of which showed structural and/or functional deficiencies of the imaginal discs. The mutants were grouped according to the size and morphology of their discs as follows: 1. discs normal: 18 mutants. 2. discs small: 2 mutants. 3. discs degenerate: 4 mutants. 4. discless: 1 mutant. 5. discs heterogeneous: 2 mutants. Preliminary characterization of the mutants included a study of disc morphology, puparium formation and pupal molt, in vivo and in vitro evagination of the imaginal discs, autonomy of the mutation in the disc tissue (differentiation after transplantation and gynander mosaicism test). Possible relations between disc morphology and the former characteristics are discussed.     

Combining coordination chemistry with hydrogen bonds: perturbation of the structures by interaction of an organotin(IV) complex with O-donor solvent molecules

We have examined the role of different solvents in the crystallisation process of cis-octahedral, diphenyltin(IV)-bis-cupferronato complex, Ph₂Sn(cupf)₂ (1), where . The Mössbauer spectra of frozen chloroform solution of 1 revealed the presence of cis and trans isomers. This cis-trans isomerisation was investigated by Mössbauer spectroscopy and the results inspired the synthesis of two new heptacoordinated derivatives: Ph₂Sn(cupf)₂(H₂O) (2) and Ph₂Sn(cupf)₂(EtOH) · EtOH (3). In both compounds, the O-donor solvent molecules (H₂O, EtOH) form novel Sn-O bonds with the Ph₂Sn(IV) centre of 1, consequently the phenyl groups attached to tin undergo an intramolecular rearrangement. Compound 2 contains O-H ? O hydrogen bonded infinite chains. In compound 3, O-H ? O hydrogen-bonds and short O ? O contacts assemble the complexes and uncoordinated solvent molecules into dimeric supramolecules. These solvents have structure-determining roles at both molecular and supramolecular levels: at molecular level the coordination of solvent determines intramolecular rearrangement by changing the conformation of the parent unsolvated complex, whilst at supramolecular level they control the association of solvated molecules via hydrogen bonds.     

Chiroptical properties of cation complexes of chiral phenazino-18-crown-6 ether-type hosts

Herein we report CD spectroscopic studies on complexes of (R,R)-dimethyl-, (R,R)-diisobutyl-, and (S,S)-di-sec-butyl-phenazino-18-crown-6 ligands (Scheme 1) with selected alkali (Na+, K+), alkaline earth (Mg2+, Ca2+), and transition-metal (Ag+, Zn2+, Ni2+, Cd2+, Pb2+) cations. The complexation was monitored in the 300- to 240-nm region of the CD spectra comprising mainly the 1Bb band of the heteroaromatic subunit. The CD spectra of the complexes showed an unexpected diversity. In the most characteristic 1Bb spectral region, the number, position, and intensity of band(s) depend not only on the heteroaromatic subunit and the size of the substituents but also on the diameter, ion strength, and coordination geometry of the cation. The appearance of two weak 1Bb CD bands (type-I spectra) with the sign pattern of the host is an indication of two complexes of comparable stability. The "type-II" spectra differ from that of the host in the number, sign pattern, and intensity of the bands. Complexes of transition-metal cations generally show CD spectra with more intense bands. The CD spectra of complexes of (S,S)-di-sec-butyl-phenazino-18-crown-6 ligand with Na+, K+, and Pb2+ (type III) strongly suggest exciton coupling caused by the closeness of the heteroaromatic rings of two 1:1 complex molecules.