Strong nucleosomes reside in meiotic centromeres of C. elegans

Recently discovered strong nucleosomes (SNs) are characterized by strongly periodical DNA sequence, with visible rather than hidden sequence periodicity. In a quest for possible functions of the SNs, it has been found that the SNs concentrate within centromere regions of A. thaliana chromosomes . They, however, have been detected in Caenorhabditis elegans as well, although the holocentric chromosomes of this species do not have centromeres. Scrutinizing the SNs of C. elegans and their distributions along the DNA sequences of the chromosomes, we have discovered that the SNs are located mainly at the ends of the chromosomes of C. elegans. This suggests that, perhaps, the ends of the chromosomes fulfill some function(s) of centromeres in this species, as also indicated by the cytogenetic studies on meiotic chromosomes in spermatocytes of C. elegans, where the end-to-end association is observed. The centromeric involvement of the SNs, also found in A. thaliana, opens new horizons for the chromosome and centromere structure studies.     

Sequence-directed Mapping of Nucleosome Positions

Abstract

A nucleosome DNA sequence probe is designed that combines recently derived RR/YY counter-phase and AA/TT in-phase periodical patterns. A simple nucleosome mapping procedure is introduced for prediction of the nucleosome positions in the sequence of interest, to serve as a guide for experimental studies of the chromatin structure.     

Antioxidant and antimicrobial actions of the clubmoss <Emphasis Type="Italic">Lycopodium clavatum</Emphasis> L.

Purpose of the present study was to evaluate antioxidant, antibacterial, antifungal, and antiviral activities of the petroleum ether, chloroform, ethyl acetate and methanol extracts as well as the alkaloid fraction of Lycopodium clavatum L. (LC) from Lycopodiaceae growing in Turkey. Antioxidant activity of the LC extracts was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging method at 0.2 mg/ml using microplate-reader assay. Antiviral assessment of LC extracts was evaluated towards the DNA virus Herpes simplex (HSV) and the RNA virus Parainfluenza (PI-3) using Madin-Darby Bovine Kidney (MDBK) and Vero cell lines. Antibacterial and antifungal activities of the extracts were tested against standard and isolated strains of the following bacteria; Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Acinobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis as well as the fungi; Candida albicans and C. parapsilosis. All of the extracts possessed noteworthy activity against ATCC strain of S. aureus (4 μg/ml), while the LC extracts showed reasonable antifungal effect. On the other hand, we found that only the chloroform extract was active against HSV (16–8 μg/ml), while petroleum ether and alkaloid extracts inhibited potently PI-3 (16–4 μg/ml and 32–4 μg/ml, respectively). However, all of the extracts had insignificant antiradical effect on DPPH. In addition, we also analyzed the content of the alkaloid fraction of the plant by capillary gas chromatography-mass spectrometry (GC-MS) and identified lycopodine as the major alkaloid.     

Alternative splicing in intracellular loop connecting domains II and III of the alpha 1 subunit of Cav1.2 Ca2+ channels predicts two-domain polypeptides with unique C-terminal tails

Novel splice variants of the alpha(1) subunit of the Ca(v)1.2 voltage-gated Ca(2+) channel were identified that predicted two truncated forms of the alpha(1) subunit comprising domains I and II generated by alternative splicing in the intracellular loop region linking domains II and III. In rabbit heart splice variant 1 (RH-1), exon 19 was deleted, which resulted in a reading frameshift of exon 20 with a premature termination codon and a novel 19-amino acid carboxyl-terminal tail. In the RH-2 variant, exons 17 and 18 were deleted, leading to a reading frameshift of exons 19 and 20 with a premature stop codon and a novel 62-amino acid carboxyl-terminal tail. RNase protection assays with RH-1 and RH-2 cRNA probes confirmed the expression in cardiac and neuronal tissue but not skeletal muscle. The deduced amino acid sequence from full-length cDNAs encoding the two variants predicted polypeptides of 99.0 and 99.2 kDa, which constituted domains I and II of the alpha(1) subunit of the Ca(v)1.2 channel. Antipeptide antibodies directed to sequences in the second intracellular loop between domains II and III identified the 240-kDa Ca(v)1.2 subunit in sarcolemmal and heavy sarcoplasmic reticulum (HSR) membranes and a 99-kDa polypeptide in the HSR. An antipeptide antibody raised against unique sequences in the RH-2 variant also identified a 99-kDa polypeptide in the HSR. These data reveal the expression of additional Ca(2+) channel structural units generated by alternative splicing of the Ca(v)1.2 gene.     

Effect of fish oil supplementation on plasma oxidant/antioxidant status in rats

The aim of this study was to investigate effect of dietary omega-3 fatty acid supplementation on the indices of in vivo lipid peroxidation and oxidant/antioxidant status of plasma in rats. The plasma thiobarbituric acid reactive substances (TBARS) and nitric oxide (NO) levels, and activities of xanthine oxidase (XO), superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were studied in male Wistar Albino rats after ingestion of 0.4 g/kg fish oil (rich in omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid) for 30 days and compared to untreated control rats. The rats in the treated group had significantly higher SOD activity (P < 0.001), NO levels (P < 0.01) and decreased TBARS levels (P < 0.05) with respect to controls whereas GSH-Px and XO activities were not significantly different between the groups. None of the measured parameters had significant correlation with each other in both groups. We conclude that dietary supplementation of omega-3 fatty acids may enhance resistance to free radical attack and reduce lipid peroxidation. These results support the notion that omega-3 fatty acids may be effective dietary supplements in the management of various diseases in which oxidant/antioxidant defence mechanisms are decelerated.     

Synthesis of a radioactive thiol reagent, 1-S-[3H]carboxymethyl-dithiothreitol: identification of the phosphorylation sites by N-terminal peptide sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

A novel radioactive thiol reagent, 1-S-[3H]carboxymethyl-dithiothreitol (DTT-S-C[3H(2)]CO(2)H, [3H]CM-DTT), was designed and synthesized at the micromole level by reaction of dithiothreitol with tritiated iodoacetic acid (I-C[3H(2)].CO(2)H). The reaction progress was followed by reverse-phase high-performance liquid chromatography (RP-HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The usefulness of the synthesized reagent was evaluated in a series of experimental approaches. (i) The synthetic phosphopeptide, NSVS(P)EEGRGDSV, was derivatized by [3H]CM-DTT separated from excess reagent by RP-HPLC. The extent of derivatization was quantitated in terms of the mol of P-Ser/mol of peptide by 3H counting, and the location of the phosphoserine was defined by the N-terminal Edman degradation sequence analysis as being the fourth amino acid residue from the N terminus. (ii) A sample of trypsin-digested alpha-casein was derivatized with [3H]CM-DTT, peptides were separated by RP-HPLC, and aliquots of each fraction were counted for 3H label within the peptide map which rapidly pinpointed the original four phosphoserine-containing peptides. This demonstrated the utility of the synthesized radioactive thiol agent in rapid purification and identification of phosphopeptides from HPLC peptide mapping of proteolytic digests of phosphoproteins. (iii) The [3H]CM-DTT was also used to determine the extent of phosphorylation of phosphoproteins both qualitatively by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography and quantitatively by 3H counting. The synthesized radioactive thiol reagent [3H]CM-DTT proved to be very efficient and sensitive and should be adaptable to a wide range of routinely utilized laboratory approaches in many fields of the biological sciences.     

Whole body exposure of rats to microwaves emitted from a cell phone does not affect the testes

The objective of this study was to investigate the effects of radiofrequency radiation emitted from cellular phones on the lipid composition, malondialdehyde concentration, p53 immune reactivity, sperm count, morphology, histological structure of testes, and on rectal temperature of rats exposed to microwave radiation emitted from cellular phones. Sixteen Spraque-Dawley rats were separated into two groups of eight, sham exposed (control) and experimental. The rats were confined in plexiglas cages specially designed for this study, and cellular phones were placed 0.5 cm under the cages. For the experimental group, cellular phones were activated 20 min per day (7 days a week) for 1 month. For the control group, the cellular phones were placed beneath the cages for 20 min a day, but the phones were turned off. Rectal temperatures were measured weekly. For 250 mW radiated power, the whole body average SAR (rms) is 0.52 W/kg and 1 g averaged peak SAR (rms) is 3.13 W/kg. The Mann-Whitney U-test was used for statistical comparisons of groups. No statistically significant alteration in any of the endpoints was noted. This study found no evidence suggesting an adverse effect of cell phone exposure on measures of testicular function or structure.     

Constitutive expression of functional 4-1BB (CD137) ligand on carcinoma cells

Members of the TNF superfamily, including Fas, Fas ligand, and CD40, have been shown to be expressed on tumor cells. In the studies described in this work, we report that another family member, the ligand for 4-1BB (CD137), is expressed on various human carcinoma cell lines, on cells of solid tumors derived from these cell lines, and cells obtained from human tumors. Expression of 4-1BB ligand (4-1BBL) mRNA was detected by both RT-PCR and Northern blot analysis, and expression of 4-1BBL protein was detected by Western blot analysis of whole cell lysates and by FACS analysis of tumor cells and cell lines. Incubation of tumor cells with a 4-1BB-Ig fusion protein led to the production of IL-8 by the cells, demonstrating that the 4-1BBL is functionally active and signals back into the tumor cells. Furthermore, 4-1BBL expressed on the carcinoma cells functioned as a costimulatory molecule for the production of cytokines (most notably IFN-gamma) in cocultures of T cells and tumor cells. These findings suggest that 4-1BBL expressed on carcinoma cells may significantly influence the outcome of a T cell-tumor cell interaction.     

Association and impact of <Emphasis Type="Italic">XPG Asp</Emphasis> 1104 <Emphasis Type="Italic">His</Emphasis> gene polymorphism in HIV 1 disease progression to AIDS among north Indian HIV seropositive individuals

Various efforts made to stop the deadly epidemic of HIV since its discovery in 1983 remain unsuccessful and this virus still continues to claim the lives of millions of individuals every year. The viral effect in the cell is complicated and the overall disease outcome is the result of interaction between a few viral proteins and complex host immune response. Because it has been reported that XPG (Xeroderma pigementesum group G) gene does play a role in reducing UV induced apoptosis and participate in Nucleotide Excision Repair (NER) process of DNA damage, it was hypothesized that polymorphism in this gene may have a role in HIV 1 disease progression to AIDS. The aim of the present study, therefore, was to find out the association between XPG gene polymorphism and its effect on the rate of HIV 1 disease progression to AIDS. 300 HIV seropositive cases and an equal number of age and sex matched controls were recruited for the study from north Indian population. The PCR-RFLP method was utilized to genotype 600 study subject for the XPG Asp ¹¹⁰⁴ His gene polymorphism. There was significant difference in the frequency of the His/His variant genotype (OR 1.95, 95% CI = 1.93–3.63, P = 0.04) between cases and controls indicating a probable role of this gene in host viral interactions.