Effects of melatonin and antagonists of MT1 and MT2 receptors on somatic pain induced within the fixed circadian rhythm

We studied behavioral pain-related reactions (PRRs) induced in mice by subcutaneous injections of 5% formalin within different phases of the fixed circadian illumination rhythm under conditions of administration of exogenous melatonin and of blocking of MT1 and MT2 melatonin receptors. It was demonstrated that modulation of experimentally induced somatic pain depends considerably on the phase of the preset circadian rhythm. In the norm, the duration of PRRs in the middle of the dark phase was 30% smaller than that in the middle of the light phase. Administration of exogenous melatonin in the middle of the light phase decreased the duration of episodes of noxious behavior by 43%, on average. Injections of melatonin within the dark phase resulted in no significant changes in the duration of PRRs. In the dark phase, the blockade of MT1 receptors by luzindole led to an increase in the duration of PRRs by 45%, as compared with the norm, while in the light phase we observed no significant alterations of this duration under conditions of blocking of the above-mentioned receptors. The blockade of MT2 receptors by prazocine in the middle of dark and light phases increased the durations of PRRs by 92 and 28%, respectively. Our data indicate that the analgesic effect of melatonin depends significantly on the level of this hormone in the organism; in turn, such a level is determined by the illumination conditions. The antinoxious effect of melatonin is mediated by MT receptors, in particular by MT2 receptors. Neirofiziologiya/Neurophysiology, Vol. 39, No. 3, pp. 255–259, May–June, 2007.     

Small RNA inhibits infection by downy mildew pathogen Hyaloperonospora arabidopsidis

Gene silencing exists in eukaryotic organisms as a conserved regulation of the gene expression mechanism. In general, small RNAs (sRNAs) are produced within the eukaryotic cells and incorporated into an RNA-induced silencing complex (RISC) within cells. However, exogenous sRNAs, once delivered into cells, can also silence target genes via the same RISC. Here, we explored this concept by targeting the Cellulose synthase A3 (CesA3) gene of Hyaloperonospora arabidopsidis (Hpa), the downy mildew pathogen of Arabidopsis thaliana. Hpa spore suspensions were mixed with sense or antisense sRNAs and inoculated onto susceptible Arabidopsis seedlings. While sense sRNAs had no obvious effect on Hpa pathogenicity, antisense sRNAs inhibited spore germination and hence infection. Such inhibition of infection was not race-specific, but dependent on the length and capping of sRNAs. Inhibition of infection by double stranded sRNA was more efficient than that observed with antisense sRNA. Thus, exogenous sRNA targeting conserved CesA3 could suppress Hpa infection in Arabidopsis, indicating the potential of this simple and efficient sRNA-based approach for deciphering gene functions in obligate biotrophic pathogens as well as for R-gene independent control of diseases in plants.     

Next-generation sequencing of flow-sorted wheat chromosome 5D reveals lineage-specific translocations and widespread gene duplications

Background

The ~17 Gb hexaploid bread wheat genome is a high priority and a major technical challenge for genomic studies. In particular, the D sub-genome is relatively lacking in genetic diversity, making it both difficult to map genetically, and a target for introgression of agriculturally useful traits. Elucidating its sequence and structure will therefore facilitate wheat breeding and crop improvement.

Results

We generated shotgun sequences from each arm of flow-sorted Triticum aestivum chromosome 5D using 454 FLX Titanium technology, giving 1.34× and 1.61× coverage of the short (5DS) and long (5DL) arms of the chromosome respectively. By a combination of sequence similarity and assembly-based methods, ~74% of the sequence reads were classified as repetitive elements, and coding sequence models of 1314 (5DS) and 2975 (5DL) genes were generated. The order of conserved genes in syntenic regions of previously sequenced grass genomes were integrated with physical and genetic map positions of 518 wheat markers to establish a virtual gene order for chromosome 5D.

Conclusions

The virtual gene order revealed a large-scale chromosomal rearrangement in the peri-centromeric region of 5DL, and a concentration of non-syntenic genes in the telomeric region of 5DS. Although our data support the large-scale conservation of Triticeae chromosome structure, they also suggest that some regions are evolving rapidly through frequent gene duplications and translocations.

Sequence accessions

EBI European Nucleotide Archive, Study no. ERP002330

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1080) contains supplementary material, which is available to authorized users.     

In vitro effects of some drugs on human erythrocyte glutathione reductase

The effects of ketotifen, meloxicam, phenyramidol-HCl and gadopentetic acid on the enzyme activity of GR were studied using human erythrocyte glutathione reductase (GR) enzymes in vitro. The enzyme was purified 209-fold from human erythrocytes in a yield of 19% with 0.31?U/mg. The purification procedure involved the preparation of haemolysate, ammonium sulphate precipitation, 2',5'-ADP Sepharose 4B affinity chromatography and Sephadex G-200 gel filtration chromatography. Purified enzyme was used in the in vitro studies. In the in vitro studies, IC(50) values and K(i) constants were 0.012?mM and 0.0008?±?0.00021?mM for ketotifen; 0.029?mM and 0.0061?±?0.00127?mM for meloxicam; 0.99?mM and 0.4340?±?0.0890?mM for phenyramidol-HCl; 138?mM and 28.84?±?4.69?mM for gadopentetic acid, respectively, showing the inhibition effects on the purified enzyme. Phenyramidol-HCl showed competitive inhibition, whereas the others showed non-competitive inhibition.     

On the excited-state energy transfer between tryptophan residues in proteins: the case of penicillin acylase

The problem, whether excited-state energy transfer occurs between Trp residues in a multi-tryptophan proteins and if it does, what kind of changes it induces in different parameters of protein fluorescence, is currently under active investigation. In our previous paper [Biophys. Chem. 72 (1998) 265], the energy transfer was found and studied in detail for Na,K-ATPase. It was shown that this transfer influences all parameters of fluorescence emission, which is detected at site-selective conditions (red-edge of excitation, blue and red edges of emission). Present experiments were performed on unusually tryptophan-rich protein, bacterial penicillin acylase (28 Trp per dimer of 82 kDa) and were aimed to extend these observations. They demonstrate substantial heterogeneity in the environments of tryptophan residues within the protein structure. This suggests, that in the present case, if the energy transfer exists, it should be directed from short-wavelength-emitting to long-wavelength-emitting tryptophan residues and thus could be easily observed by a number of time-resolved and steady-state fluorescence techniques. Unexpectedly, no signature of inter-tryptophan energy transfer was found.     

Subgenomic analysis of microRNAs in polyploid wheat

In this study, a survey of miRNAs using the next-generation sequencing data was performed at subgenomic level. After analyzing shotgun sequences from chromosome 4A of bread wheat (Triticum aestivum L.), a total of 68 different miRNAs were predicted in silico, of which 37 were identified in wheat for the first time. The long arm of the chromosome was found to harbor a higher variety (51) and representation (3,928) of miRNAs compared with the short arm (49; 2,226). Out of the 68 miRNAs, 32 were detected to be common to both arms, revealing the presence of separate miRNA clusters in the two chromosome arms. The differences in degree of representation of the different miRNAs were found to be highly variable, ranging 592-fold, which may have an effect on target regulation. Targets were retrieved for 62 (out of 68) of wheat-specific, newly identified miRNAs indicated that fundamental aspects of plant morphology such as height and flowering were predicted to be affected. In silico expression blast analysis indicated 24 (out of 68) were found to give hits to expressed sequences. This is the first report of species- and chromosome-specific miRNAs.     

细胞黏附和突触发生

突触是神经网络中神经细胞间相互连接的基本工作单位。突触的分子构建是一个引人入胜的问题,数十年来一直吸引着科学家们的注意。冯德培和许多其他科学家早期在神经肌肉接头领域做出了开创性的研究工作。至今,神经肌肉接头仍是一个杰出的突触标本,为我们研究中枢神经系统的突触形成铺平了道路。近期的研究又有新的亮点,发现一组细胞黏附分子具有很强的突触发生作用,使中枢突触形成的分子机制更加明朗。本文综述了这些表达在非神经细胞里能引起中枢突触形成的细胞黏附分子的功能与特性。     

Is There a Possible Relation Between Atrophic Gastritis and Premature Atherosclerosis?

BACKGROUND: In this study, we have aimed to show the possible relation between atrophic gastritis and premature atherosclerosis via hyperhomocysteinemia. MATERIALS AND METHODS: Thirty-four patients with atrophic gastritis were enrolled to the study. The control group consisted of 35 patients with non-atrophic gastritis. Classical cardiovascular disease risk factors did not significantly differ between atrophic gastritis and control subjects. The presence and degree of atrophic gastritis were assessed histologically and Helicobacter pylori infection was determined by both histologic and serologic methods. Body mass index was measured by standard technique blood fasting glucose, serum creatinine, total cholesterol, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, vitamin B12, folic acid, and homocysteine levels were measured by biochemical methods. Carotid intima-media thickness was measured by B-mode ultrasonography to examine the premature atherosclerosis. RESULTS: Plasma vitamin B12 levels were significantly lower (p = .00) and homocysteine levels were significantly higher (p = .01) in the atrophic gastritis group. There was no statistically significant difference in plasma folic acid levels between the two groups (p = .728). Carotid intima-media thickness was higher in the atrophic gastritis group than in the control group (0.516 mm versus 0.465 mm), but this difference did not show any statistical significance (p = .062). CONCLUSION: Our results showed that atrophic gastritis may cause hyperhomocysteinemia, which is an independent risk factor for atherosclerosis and cardiovascular diseases. However, when compared with controls, carotid intima-media thickness of the atrophic gastritis patients was found to be higher but did not reach statistically significant levels.