Epigenetic and pharmacological control of pigmentation via Bromodomain Protein 9 (BRD9)

Lineage-specific differentiation programs are activated by epigenetic changes in chromatin structure. Melanin-producing melanocytes maintain a gene expression program ensuring appropriate enzymatic conversion of metabolites into the pigment, melanin, and transfer to surrounding cells. During neuroectodermal development, SMARCA4 (BRG1), the catalytic subunit of SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complexes, is essential for lineage specification. SMARCA4 is also required for development of multipotent neural crest precursors into melanoblasts, which differentiate into pigment-producing melanocytes. In addition to the catalytic domain, SMARCA4 and several SWI/SNF subunits contain bromodomains which are amenable to pharmacological inhibition. We investigated the effects of pharmacological inhibitors of SWI/SNF bromodomains on melanocyte differentiation. Strikingly, treatment of murine melanoblasts and human neonatal epidermal melanocytes with selected bromodomain inhibitors abrogated melanin synthesis and visible pigmentation. Using functional genomics, iBRD9, a small molecule selective for the bromodomain of BRD9 was found to repress pigmentation-specific gene expression. Depletion of BRD9 confirmed a requirement for expression of pigmentation genes in the differentiation program from melanoblasts into pigmented melanocytes and in melanoma cells. Chromatin immunoprecipitation assays showed that iBRD9 disrupts the occupancy of BRD9 and the catalytic subunit SMARCA4 at melanocyte-specific loci. These data indicate that BRD9 promotes melanocyte pigmentation whereas pharmacological inhibition of BRD9 is repressive.     

Comparative Study of Chemical Composition,Cholinesterase Inhibition and Antioxidant Potential of Mentha pulegium L. Essential Oil

Perennial plant Mentha pulegium L. (pennyroyal, Lamiaceae) can be found in Europe and Mediterranean. In areas where it thrives, M. pulegium is used in nutrition and as medicinal plant. Essential oil of M. pulegium is also a frequent constituent of foods and fragrances, because of mint-like odor. Regarding the use of M. pulegium in traditional medicine and nutrition, as well as fact that essential oils are potential sources of bioactive components, this study was conducted to examine the chemical composition of essential oil of M. pulegium wild growing in Bosnia and Herzegovina and its biological activity. The chemical profile testing was made using GC/MS and GC/FID technique. Potential of cholinesterase inhibition was tested by Ellman's assay. The antioxidant activity was tested by DPPH and FRAP assay. The dominant components in analyzed oil were pulegone 54.4 %, p-menthone 14.0 % and piperitenone 12.8 %. Good antioxidant activity and moderate cholinesterase inhibition potential of tested essential oil indicates to possibility of its use in treatment of diseases related to free radicals, Alzheimer disease and as lipid protecting antioxidant.     

ATP and ADP hydrolysis in cell membranes from rat myometrium

Extracellular nucleotides affect female reproductive functions, fertilization, and pregnancy. The aim of this study was to investigate biochemical characteristics of ATP and ADP hydrolysis and identify E-NTPDases in myometrial cell membranes from Wistar albino rats. The apparent K _m values were 506.4?±?62.1 and 638.8?±?31.3?μM, with a calculated V _max (app) of 3,973.0?±?279.5 and 2,853.9?±?79.8?nmol/min/mg for ATP and ADP, respectively. The enzyme activity described here has common properties characteristic for NTPDases: divalent cation dependence; alkaline pH optimum for both substrates, insensitivity to some of classical ATPase inhibitors (ouabain, oligomycine, theophylline, levamisole) and significant inhibition by suramine and high concentration of sodium azides (5?mM). According to similar apparent K_m values for both substrates, the ATP/ADP hydrolysis ratio, and Chevillard competition plot, NTPDase1 is dominant ATP/ADP hydrolyzing enzyme in myometrial cell membranes. RT-PCR analysis revealed expression of three members of ectonucleoside triphosphate diphosphohydrolase family (NTPDase 1, 2, and 8) in rat uterus. These findings may further elucidate the role of NTPDases and ATP in reproductive physiology.     

Clinical utility of red cell distribution width in alcoholic and non-alcoholic liver cirrhosis

Red blood cell distribution width (RDW) is a measure of the variation of red blood cell width that is reported as apart of standard complete blood count. Red blood cell distribution width results are often used together with mean corpuscular volume (MCV) results to figure out mixed anemia. The aim of our study was to compare the values of RDW in alcoholic and non-alcoholic liver cirrhosis and to determine if RDW follows the severity of disease according to Child-Pugh score. We retrospectively analyzed 241 patients (176 men and 65 women) with liver cirrhosis and anemia, defined as a hemoglobin value < 130 g/L in men and < 120 g/L in women, which were hospitalized in our Division in a period between 2006 and 2008. Patients were divided in two groups; in first were patients with alcoholic liver cirrhosis, and in second with non-alcoholic cirrhosis. Severity of disease was determined according to Child-Pugh score. Red blood cells distribution width Normal reference range is 11-15%. Alcoholic liver cirrhosis had 204 patients (85%) while non-alcoholic cirrhosis had 37 patients (15%). In group of alcoholic cirrhosis the average RDW was 16.8%. In relation to severity of disease the average RDW for Child-Pugh A was 16.80%, for Child-Pugh B was 16.92%, for Child-Pugh C was 17.10%. In the group of non-alcoholic cirrhosis the average RDW was 16.73% and in relation to severity of disease for Child-Pugh A was 16.25%, for Child-Pugh B 17.01% and for Child-Pugh C was 16.87%. We didn't find statistically significant difference of RDW between alcoholic and non alcoholic cirrhosis (p > 0.05) and we didn't proved any statistically significant increase of RDW in relation to severity of disease in group of alcoholic cirrhosis (p = 0.915) nor in group of patients with non-alcoholic cirrhosis (p = 0.697). Our study showed that RDW had not any clinical value in differentiation of anemia neither in alcoholic and non-alcoholic liver cirrhosis nor in severity of liver disease.     

Chronobiological perspectives on myocardial electrophysiological parameters under three types of general anaesthesia in a rat model

The specific aim of the present study, with respect to dependence on the light–dark (LD) cycle under in vivo conditions in spontaneously breathing rats was to review initial state in electrophysiological parameters that may predict the development of heart rhythm disorders in pentobarbital (40 mg/kg), ketamine–xylazine (100 + 15 mg/kg) and zoletil (30 mg/kg) anaesthetized animals. The study was performed using female Wistar rats that were adaptated to an LD cycle (12 h:12 h). Heart rate, PQ and QT intervals were evaluated for their dependence on the LD cycle. The longest PQ interval duration is under zoletil anaesthesia in the light period and the longest QT interval duration is under ketamine–xylazine anaesthesia in both light periods. We concluded that the most significant predisposition toward the development of ventricular arrhythmias originating from disorders of impulse production and conduction occurred under zoletil anaesthesia in the light period; those resulting from disorders in the dispersion of refractory periods occurred under ketamine–xylazine anaesthesia in both the light periods.     

Total Mercury Levels in Commercial Fish in Market of the Republic of Srpska,Bosnia and Herzegovina

Biological Trace Element Research - The mercury concentration was quantified in frozen and canned fish found in the market of the Republic of Srpska, Bosnia and Herzegovina. Using the method of...     

Decolorization of textile dyes by whole cultures of Ischnoderma resinosum and by purified laccase and Mn-peroxidase

Ischnoderma resinosum produced extracellular ligninolytic enzymes laccase and MnP. The activity of laccase achieved the maximum on day 10 (29.4 U L⁻¹), the MnP on day 14 (34.5 U L⁻¹). Laccase and Mn-peroxidase were purified from the culture liquid using gel permeation and ion-exchange chromatographies. Purified Mn-peroxidase performed decolorization of all textile dyes tested (Reactive Black 5, Reactive Blue 19, Reactive Red 22 and Reactive Yellow 15). Laccase was inactive with Reactive Black 5 and Reactive Red 22, while all dyes were decolorized after addition of the redox mediators violuric acid (VA) and hydroxybenzotriazole (HBT). The culture liquid from I. resinosum cultures was also able to decolorize all dyes as well as the synthetic dyebaths in the presence of VA and HBT. The highest decolorization rates were detected in acidic pH (3–4).