Chemical composition,antioxidant and antimicrobial activities of the essential oil and methanolic extract of Ferulago bernardii Tomk. & M. Pimen of Iran

The aim of the study was to investigate chemical composition, antioxidant, antibacterial and antifungal activities of the essential oil (EO), polar and nonpolar sub-fractions of methanolic extract of Ferulago bernardii. The chemical constituent of the EO was identified by means of GC–MS. The antimicrobial activities of the EO, polar and nonpolar extracts were evaluated by micro-dilution and agar disc diffusion assays. The antioxidant activity was measured by 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) free radical scavenging activity assay. The main components of the EO were α-pinene (35.03%), z-β-ocimene (14.24%) and bornyl acetate (11.64%). Bacillus cereus and Salmonella typhimurium were the most susceptible and resistant to the antibacterial activity of the essential oil and extract, respectively. The free radical scavenging activities of all extracts and the essential oil were in the order: polar > non-polar > EO. Our findings indicate that F. bernardii essential oil and methanolic extract has a potential to be applied as antimicrobial and antioxidant agent.     

Bioinformatic and biochemical characterization of DCXR and DHRS2/4 from Caenorhabditis elegans

Several reductases belonging to the large enzyme superfamily of the short-chain dehydrogenases/reductases (SDR) are involved in the reductive metabolism of carbonyl containing xenobiotics. In order to characterize the human enzymes dicarbonyl/l-xylulose reductase (DCXR), and dehydrogenase/reductase members 2 and 4 (DHRS2, DHRS4) in terms of metabolism of xenobiotics, orthologues from the model organism Caenorhabditis elegans (C. elegans) were identified by using hidden Markov models that were developed in the present study. Accordingly, we describe the characterization of proteins from C. elegans as orthologous to the human enzymes DCXR and DHRS2/4 using a combined approach of bioinformatic and biochemical methods. With the hidden Markov model based system we identified the C. elegans proteins SDR20C18, SDR25C21 and SDR25C22 as being homologous to the human enzymes DCXR, and DHRS2 or DHRS4, respectively. After cloning and overexpression of these three C. elegans genes in Escherichia coli we could purify SDR20C18 and SDR25C22 as soluble proteins by Ni-affinity chromatography, whereas recombinant SDR25C21 was only found in inclusion bodies. Both SDR20C18 (UniProtAcc: Q21929) and SDR25C22 (UniProtAcc: Q93790) were tested with a variety of xenobotic carbonyl compounds as substrates. A comparison of the catalytic activities of SDR20C18 and SDR25C22 with well-known substrates of the human forms revealed that SDR20C18 is the DCXR-orthologue enzyme to the human enzyme and that SDR25C22 might be a DHRS2/4 homologue. Due to their high sequence identity, it was so far not possible to distinguish between SDR25C22 and the human DHRS2/4 proteins by means of sequence analysis alone. However, the study of homologue genes in the model organism C. elegans can provide valuable information on the putative physiological role of the corresponding human form.     

Is the Cerebellum the Optimal Reference Region for Intensity Normalization of Perfusion MR Studies in Early Alzheimer’s Disease?

The cerebellum is the region most commonly used as a reference when normalizing the intensity of perfusion images acquired using magnetic resonance imaging (MRI) in Alzheimer’s disease (AD) studies. In addition, the cerebellum provides unbiased estimations with nuclear medicine techniques. However, no reports confirm the cerebellum as an optimal reference region in MRI studies or evaluate the consequences of using different normalization regions. In this study, we address the effect of using the cerebellum, whole-brain white matter, and whole-brain cortical gray matter in the normalization of cerebral blood flow (CBF) parametric maps by comparing patients with stable mild cognitive impairment (MCI), patients with AD and healthy controls. According to our results, normalization by whole-brain cortical gray matter enables more sensitive detection of perfusion abnormalities in AD patients and reveals a larger number of affected regions than data normalized by the cerebellum or whole-brain white matter. Therefore, the cerebellum is not the most valid reference region in MRI studies for early stages of AD. After normalization by whole-brain cortical gray matter, we found a significant decrease in CBF in both parietal lobes and an increase in CBF in the right medial temporal lobe. We found no differences in perfusion between patients with stable MCI and healthy controls either before or after normalization.     

Effects of Silver Nanoparticles on Burn Wound Healing in a Mouse Model

Biological Trace Element Research - Healing of injuries caused by exposure to heat has been discussed in many studies, although a few drugs have been shown to produce satisfactory results. In this...     

Thermostable alkaline phytase from Bacillus sp. MD2: effect of divalent metals on activity and stability

Phytate, the major source of phosphorus in seeds, exists as a complex with different metal ions. Alkaline phytases are known to dephosphorylate phytate complexed with calcium ions in contrast to acid phytases that act only on phytic acid. A recombinant alkaline phytase from Bacillus sp. MD2 has been purified and characterized with respect to the effect of divalent metal ions on the enzyme activity and stability. The presence of Ca²⁺ on both the enzyme and the substrate is required for optimal activity and stability. Replacing Ca²⁺ with Ba²⁺, Mn²⁺, Mg²⁺ and Sr²⁺ in the phytase resulted in the expression of > 90% of the maximal activity with calcium-phytate as the substrate, while Fe²⁺ and Zn²⁺ rendered the enzyme inactive. On the other hand, the calcium loaded phytase showed significant activity (60%) with sodium phytate and lower activity (17-20%) with phytate complexed with only Mg²⁺, Sn²⁺ and Sr²⁺, respectively. On replacing Ca²⁺ on both the enzyme and the substrate with other metal ions, about 20% of the maximal phytase activity was obtained only with Mg²⁺ and Sr²⁺, respectively. Only Ca²⁺ resulted in a marked increase in the melting temperature (T_m) of the enzyme by 12-21 °C, while Ba²⁺, Mn²⁺, Sr²⁺ or Cu²⁺ resulted in a modest (2-3.5 °C) increase in T_m. In the presence of 1-5 mM Ca²⁺, the optimum temperature of the phytase activity was increased from 40 °C to 70 °C, while optimum pH of the enzyme shifted by 0.4-1 pH unit towards the acidic region.     

Heterologous expression of Anabaena sp. PCC7120 cyanophycin metabolism genes cphA1 and cphB1 in Sinorhizobium (Ensifer) meliloti 1021

Sinorhizobium meliloti infects leguminous plants resulting in a nitrogen-fixing symbiosis. Free living cells accumulate poly(3-hydroxybutyrate) (PHB) as carbon and energy source under imbalanced growth conditions. The cphA1 ₇₁₂₀ gene encoding a cyanophycin (CGP) synthetase of Anabaena sp. PCC7120 in plasmids pVLT31::cphA1 ₇₁₂₀ and pBBR1MCS-3::cphA1 ₇₁₂₀ was expressed in the wild-type S. meliloti 1021 and in a phbC-negative mutant generated in this study. Expression of cphA1 ₇₁₂₀ and accumulation of CGP in cells were studied in various media. Yeast mannitol broth (YMB) and pBBR1MCS-3::cphA1 ₇₁₂₀ yielded the highest CGP contents in both S. meliloti 1021 strains. Supplying the YMB medium with isopropyl-β-D-thiogalactopyranoside, aspartic acid, and arginine enhanced CGP contents about 2.5- and 2.8-fold in S. meliloti 1021 (pBBR1MCS-3::cphA1 ₇₁₂₀) and S. meliloti 1021 phbCΩKm (pBBR1MCS-3::cphA1 ₇₁₂₀), respectively. Varying the nitrogen-to-carbon ratio in the medium enhanced the CGP content further to 43.8% (w/w) of cell dry weight (CDW) in recombinant cells of S. meliloti 1021 phbCΩKm (pBBR1MCS-3::cphA1 ₇₁₂₀). Cells of S. meliloti 1021 (pBBR1MCS-3::cphA1 ₇₁₂₀) accumulated CGP up to 39.6% in addition to 12.1% PHB (w/w, of CDW). CGP from the S. meliloti strains consisted of equimolar amounts of aspartic acid and arginine and contained no other amino acids even if the medium was supplemented with glutamic acid, citrulline, ornithine, or lysine. CGP isolated from cells of S. meliloti 1021 (pBBR1MCS-3::cphA1 ₇₁₂₀) and S. meliloti 1021 phbCΩKm (pBBR1MCS-3::cphA1 ₇₁₂₀) exhibited average molecular weights between 20 and 25 kDa, whereas CGP isolated from Escherichia coli S17-1 (pBBR1MCS-3::cphA1 ₇₁₂₀) exhibited average molecular weight between 22 and 30 kDa. Co-expression of cyanophycinase from Anabaena sp. PCC7120 encoded by cphB1 ₇₁₂₀ in cphA1 ₇₁₂₀-positive E. coli S17-1, S. meliloti 1021, and its phbC-negative mutant gave cyanophycinase activities in crude extracts, and no CGP granules occurred. A higher PHB content in S. meliloti 1021 (pBBR1MCS-3::cphB1 ₇₁₂₀::cphA1 ₇₁₂₀) in comparison to the control indicated that the cells used CGP degradation product (β-aspartate-arginine dipeptide) to fuel PHB biosynthesis.     

The Neuroprotective Effect of Curcumin and Nigella sativa Oil Against Oxidative Stress in the Pilocarpine Model of Epilepsy: A Comparison with Valproate

Oxidative stress has been implicated to play a role in epileptogenesis and pilocarpine-induced seizures. The present study aims to evaluate the antioxidant effects of curcumin, Nigella sativa oil (NSO) and valproate on the levels of malondialdehyde, nitric oxide, reduced glutathione and the activities of catalase, Na⁺, K⁺-ATPase and acetylcholinesterase in the hippocampus of pilocarpine-treated rats. The animal model of epilepsy was induced by pilocarpine and left for 22 days to establish the chronic phase of epilepsy. These animals were then treated with curcumin, NSO or valproate for 21 days. The data revealed evidence of oxidative stress in the hippocampus of pilocarpinized rats as indicated by the increased nitric oxide levels and the decreased glutathione levels and catalase activity. Moreover, a decrease in Na⁺, K⁺-ATPase activity and an increase in acetylcholinesterase activity occurred in the hippocampus after pilocarpine. Treatment with curcumin, NSO or valproate ameliorated most of the changes induced by pilocarpine and restored Na⁺, K⁺-ATPase activity in the hippocampus to control levels. This study reflects the promising anticonvulsant and potent antioxidant effects of curcumin and NSO in reducing oxidative stress, excitability and the induction of seizures in epileptic animals and improving some of the adverse effects of antiepileptic drugs.     

CIGB-300, a proapoptotic peptide, inhibits angiogenesis in vitro and in vivo

We have previously demonstrated that a proapoptotic cyclic peptide CIGB-300, formerly known as P15-Tat delivered into the cells by the cell-penetrating peptide Tat, was able to abrogate the CK2-mediated phosphorylation and induce tumor regression when injected directly into solid tumors in mice or by systemic administration. In this work, we studied the role of CIGB-300 on the main events that take place in angiogenesis. At non-cytotoxic doses, CIGB-300 was able to inhibit adhesion, migration, and tubular network formation induced by human umbilical vein endothelial cells (HUVEC) growing upon Matrigel in vitro. Likewise, we evaluated the cellular penetration and localization into the HUVEC cells of CIGB-300. Our results confirmed a quick cellular penetration and a cytoplasmic accumulation in the early minutes of incubation and a translocation into the nuclei beginning at 12 h of treatment, with a strong presence in the perinuclear area. A microarray analysis was used to determine the genes affected by the treatment. We observed that CIGB-300 significantly decreased four genes strongly associated with tubulogenesis, growth, and differentiation of endothelial cells. The CIGB-300 was tested in vivo on chicken embryo chorioallantoic membranes (CAM), and a large number of newly formed blood vessels were significantly regressed. The results suggested that CIGB-300 has a potential as an antiangiogenic treatment. The mechanism of action may be associated with partial inhibition of VEGF and Notch pathways.     

The Mu class glutathione transferase is abundant in striated muscle and is an isoform-specific regulator of ryanodine receptor calcium channels

Members of the glutathione transferase (GST) structural family are novel regulators of cardiac ryanodine receptor (RyR) calcium channels. We present the first detailed report of the effect of endogenous muscle GST on skeletal and cardiac RyRs. An Mu class glutathione transferase is specifically expressed in human muscle. An hGSTM2-2-like protein was isolated from rabbit skeletal muscle and sheep heart, at concentrations of approximately 17-93 microM. When added to the cytoplasmic side of RyRs, hGSTM2-2 and GST isolated from skeletal or cardiac muscle, modified channel activity in an RyR isoform-specific manner. High activity skeletal RyR1 channels were inactivated at positive potentials or activated at negative potentials by hGSTM2-2 (8-30 microM). Inactivation became faster as the positive voltage was increased. Channels recovered from inactivation when the voltage was reversed, but recovery times were significantly slowed in the presence of hGSTM2-2 and muscle GSTs. Low activity RyR1 channels were activated at both potentials. In contrast, hGSTM2-2 and GSTs isolated from muscle (1-30 microM) in the cytoplasmic solution, caused a voltage-independent inhibition of cardiac RyR2 channels. The results suggest that the major GST isoform expressed in muscle regulates Ca2+ signalling in skeletal and cardiac muscle and conserves Ca2+ stores in the sarcoplasmic reticulum.     

Complete genome sequence of the myxobacterium Sorangium cellulosum

The genus Sorangium synthesizes approximately half of the secondary metabolites isolated from myxobacteria, including the anti-cancer metabolite epothilone. We report the complete genome sequence of the model Sorangium strain S. cellulosum So ce56, which produces several natural products and has morphological and physiological properties typical of the genus. The circular genome, comprising 13,033,779 base pairs, is the largest bacterial genome sequenced to date. No global synteny with the genome of Myxococcus xanthus is apparent, revealing an unanticipated level of divergence between these myxobacteria. A large percentage of the genome is devoted to regulation, particularly post-translational phosphorylation, which probably supports the strain's complex, social lifestyle. This regulatory network includes the highest number of eukaryotic protein kinase-like kinases discovered in any organism. Seventeen secondary metabolite loci are encoded in the genome, as well as many enzymes with potential utility in industry.