Chronopharmacology of Melatonin: Inhibition by Benzodiazepine Antagonism

We endeavored to determine whether three behavioral effects of melatonin in rodents, i.e., depression of locomotor activity in hamsters, analgesia in mice, and impairment of 3-mercaptopropionic acid (3-MP) convulsions, exhibited the time dependency known to occur for several neuroendocrine effects of the hormone. Activity was monitored and registered by means of an optical acto-meter, and analgesia was assessed by the hot-plate procedure. Locomotor activity, analgesia, and seizure susceptibility were maximal at the beginning of the scoto-phase and minimal at noon. The effects of melatonin on the three parameters peaked at early night. The administration of the benzodiazepine antagonist fluma-zenil, although unable by itself to modify locomotor activity, pain, or seizure threshold, blunted the activity of melatonin. These results suggest that the time-dependent effects of melatonin on specific rodent behaviors may be mediated by central synapses employing 7-aminobutyric acid (GABA) as an inhibitory transmitter.     

Fe3O4 and bimetal–organic framework Zn/Mg composite peroxide-like catalyze luminol chemiluminescence for specific measurement of atropine in Datura plant

Atropine (AT) is an anticholinergic drug. AT is abundantly in Datura plant seeds. Fe₃O₄@Zn/Mg MOF (Fe₃O₄@MOF) composite was synthesized. The compound had a high peroxidase-like activity in a chemiluminescence (CL) reaction. Addition of AT quenched CL. The linear range and limit of detection were 5–600 μg L⁻¹ and 2 × 10⁻² μg L⁻¹. This method is fast, reversible, and selective, without biodegradability effects, high accuracy, and precision for measuring AT in the Datura plant.     

Seed Priming of Bread Wheat Varieties with Growth Regulators and Nutrients Improves Salt Stress Tolerance Particularly for the Local Genotype

Journal of Plant Growth Regulation - Salt stress is a main factor limiting the production and productivity of wheat in arid and semi-arid zones. The objectives of this study were to compare the...     

The performances of the chi-square test and complexity measures for signal recognition in biological sequences

With large amounts of experimental data, modern molecular biology needs appropriate methods to deal with biological sequences. In this work, we apply a statistical method (Pearson's chi-square test) to recognize the signals appear in the whole genome of the Escherichia coli. To show the effectiveness of the method, we compare the Pearson's chi-square test with linguistic complexity on the complete genome of E. coli. The results suggest that Pearson's chi-square test is an efficient method for distinguishing genes (coding regions) form pseudogenes (noncoding regions). On the other hand, the performance of the linguistic complexity is much lower than the chi-square test method. We also use the Pearson's chi-square test method to determine which parts of the Open Reading Frame (ORF) have significant effect on discriminating genes form pseudogenes. Moreover, different complexity measures and Pearson's chi-square test applied on the genes with high value of Pearson's chi-square statistic. We also compute the measures on homologous of these genes. The results illustrate that there is a region near the start codon with high value of chi-square statistic and low complexity that is conserve between homologous genes.     

Blood Levels of Lead, Cadmium, and Mercury in Residents of Tehran

Monitoring of toxic trace elements for human blood has been of interest to researchers in the fields of environmental chemistry and medical science. The amount of blood toxic elements can reflect the disease state of the person or the environment where that person resides or works. Chronic, low-level exposure to toxic metals such as lead (Pb), cadmium (Cd), and mercury (Hg) is an increasing global problem. This study focuses on obtaining the usual value of Pb, Cd, and Hg in normal human blood. These elements were determined in 61 male and 40 female volunteers resident in Tehran (Iran). The subjects were non-drug abusers and aged 6-62 years old. Procedures were developed for the collection, storage, and preanalytical treatment of samples. The lead and cadmium were determined by graphite furnace atomic absorption spectrometry, and mercury was measured by cold vapor atomic absorption spectrometry technique. The blood levels of Pb, Cd, and Hg in normal volunteers living in Tehran were 123.75 +/- 56.42, 1.82 +/- 0.67, and 8.48 +/- 4.42 microg/L. There was no significant gender-related difference in blood Cd and Hg concentrations (p < 0.06 and p < 0.41). However, the results indicated significantly higher content of Pb in blood of males compared to females (138.11 +/- 65.43 and 101.84 +/- 51.38 microg/L, respectively, p < 0.05).     

Lysosomes of the Liver and the Duodenal Enterocytes,a Site of Handling of Two Rare Earths. Ultrastructural and Microanalytical Study

The frequent use of some trace elements such as gadolinium and terbium in medicine and modern industries make us worry about their behavior in the organism. In this work, we study the intracellular localization in the liver and in the intestinal mucosa of two rare earths, gadolinium and terbium, after intraperitoneal and intragastric administration. Three methods of observation and microanalysis were used: conventional transmission electron microscopy, secondary ion mass spectrometry, and electron probe microanalysis. After intraperitoneal administration, gadolinium and terbium were detected with phosphorus in lysosomes of hepatocytes and Küppfer cells and in territories near to biliary canalicule. One hour after intragastric administration, gadolinium and terbium were concentrated in lysosomes of the apical part of duodenal enterocytes. No gadolinium or terbium was detected in duodenum 4 days after administration. After intragastric administration, the microanalytical techniques failed to detect gadolinium or terbium in liver whatever the time of sampling. This mechanism of concentration-precipitation in the lysosomes of enterocytes limits the diffusion through the digestive barrier of foreign elements and then permits their elimination with apoptotic cells in the intestinal lumen. Some of these elements may be toxic, and none of them have a recognized physiological function. The intestinal mucosa plays an important role in the protection of the organism against the invasion of foreign elements.     

gamma-Zein secondary structure in solution by circular dichroism

The proline-rich N-terminal domain of gamma-zein has been reported in relevant processes, which include its ability to cross the cell membranes. Evidences indicate that synthetic hexapeptide (PPPVHL), naturally found in N-terminal portion of gamma-zein, can adopt the polyproline II (PPII) conformation in aqueous solution. The secondary structure of gamma-zein in maize protein bodies had been analyzed by solid state Fourier transform infrared and nuclear magnetic resonance spectroscopies. However, it was not possible to measure PPII content in physiological environment since the beta-sheet and PPII signals overlap in both solid state techniques. Here, the secondary structure of gamma-zein has been analyzed by circular dichroism in SDS aqueous solution with and without ditiothreitol (DTT), and in 60% of 2-propanol and water with DTT. The results show that gamma-zein has high helical content in all solutions. The PPII conformation was present at about 7% only in water/DTT solution.     

Evolutionary mechanisms underlying the functional divergence of duplicate genes involved in vertebrates' circadian rhythm pathway

Circadian rhythms, that are governed physiologically and behaviorally by endogenous clock, have been described in many species. Living organisms use this endogenous circadian clock to anticipate environmental transitions, perform activities at biologically advantageous times during the day, and undergo characteristic seasonal responses. Gene duplication is one of the most important mechanisms in the evolution of gene diversity. After duplication, one or both of duplicates can accumulate amino acid changes, thereby promoting functional divergence through the action of natural selection. The circadian system, like many other multigene families, has undergone this genetic revolution, and so circadian genes that are found in single copies in insects are duplicated in vertebrates. We analyzed six groups of genes involved in vertebrates' circadian rhythm pathway to find signatures of molecular evolutionary processes such as gene duplication, natural selection, recombination, and functional divergence. The obtained results, then, were used to determine what evolutionary forces have influenced the fates of duplicated genes of each group. We showed in this research that recombination has not been widespread during the evolution of circadian genes and that purifying selection has been the prominent natural pressure operating on circadian genes. We also showed that the evolution of circadian genes has been depended on gene duplication and functional divergence. Finally, we put forward models best describing the evolutionary fates of circadian duplicates.     

Coding of visual objects in the ventral stream

How are objects represented in the brain? Two facets of this question are currently under investigation. First, are objects represented by activity in a relatively small number of neurons that are each selective for the shape or identity of a specific object (a 'sparse code'), or are they represented by a pattern of activity across a large number of less selective neurons (a 'population code')? Second, how are the neurons that code for an object distributed across the cortex: are they clustered together in patches, or are they scattered widely across the cortex? The results from neurophysiology and functional magnetic resonance imaging studies are beginning to provide preliminary answers to both questions.