High-throughput microRNA profile in adult and pediatric primary glioblastomas: the role of miR-10b-5p and miR-630 in the tumor aggressiveness

Molecular Biology Reports - Glioblastoma (GBM) is the most common primary malignant neoplasm of the central nervous system and, despite the standard therapy; the patients’ prognoses remain...     

Homology modeling, molecular dynamics and QM/MM study of the regulatory protein PhoP from Corynebacterium pseudotuberculosis

Corynebacterium pseudotuberculosis is a facultatively intracellular Gram-positive bacterium that causes caseous lymphadenitis, principally in sheep and goats, though sometimes in other species of animals, leading to considerable economic losses. This pathogen has a TCS known as PhoPR, which consists of a sensory histidine kinase protein (PhoR) and an intracellular response regulator protein (PhoP). This system is involved in the regulation of proteins present in various processes, including virulence. The regulation is activated by PhoP protein phosphorylation, an event that requires a magnesium (Mg²⁺) ion. Here we describe the 3D structure of the regulatory response protein (PhoP) of C. pseudotuberculosis through molecular modeling by homology. The model generated provides the first structural information on a full-length member of the OmpR/PhoP subfamily. Classical molecular dynamics was used to investigate the stability of the model. In addition, we used quantum mechanical/molecular mechanical techniques to perform (internal, potential) energy optimizations to determine the interaction energy between the Mg²⁺ ion and the structure of the PhoP protein. Analysis of the interaction energy residue by residue shows that Asp-16 and Asp-59 play an important role in the protein–Mg²⁺ ion interactions. These results may be useful for the future development of a new vaccine against tuberculosis based on genetic attenuation via a point mutation that results in the polar residue Asp-16 and/or Asp-59 being replaced with a nonpolar residue in the DNA-binding domain of PhoP of C. pseudotuberculosis.     

Effect of Batch and Fed-Batch Growth Modes on Biofilm Formation by <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> at Different Temperatures

The influence of Listeria monocytogenes (L. monocytogenes) biofilm formation feeding conditions (batch and fed-batch) at different temperatures on biofilm biomass and activity was determined. Biofilm biomass and cellular metabolic activity were assessed by Crystal Violet (CV) staining and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT) colorimetric method, respectively. Live/Dead staining was also performed in order to get microscopic visualization of the different biofilms. Results revealed that at refrigeration temperature (4°C) a higher amount of biofilm was produced when batch conditions were applied, while at higher temperatures the fed-batch feeding condition was the most effective on biofilm formation. Moreover, independently of the temperature used, biofilms formed under fed-batch conditions were metabolically more active than those formed in batch mode. In conclusion, this work shows that different growth modes significantly influence L. monocytogenes biofilm formation on abiotic surfaces as well as the metabolic activity of cells within biofilms.     

Sulfur starvation in Lemna leads to degradation of ribulose-bisphosphate carboxylase without plant death.

Little is known about the degradation of the most abundant protein in nature, ribulose-bisphosphate carboxylase (RuBP carboxylase, EC 4.1.1.39), probably reflecting the fact that no stress situation has been identified capable of causing extensive RuBP carboxylase degradation without causing the death of the plant. We have subjected plants of Lemna minor L. to a variety of stress situations, nutritive deficiencies in particular, and have found a single condition--sulfur starvation--that caused almost complete degradation of RuBP carboxylase without causing plant death. Moreover, the enzyme was preferentially degraded under these conditions. However, when the plants were deprived of calcium, no RuBP carboxylase degradation was observed. Instead, the enzyme was oxidized and polymerized into high molecular mass aggregates. On the other hand, RuBP carboxylase shows an extreme stability when Lemna is deprived of some macronutrients (e.g. nitrogen, phosphorus, potassium, and magnesium) probably reflecting that this plant had to evolve in a way to cope with frequent shortages of such elements. The implications of these data for the role of RuBP carboxylase as a leaf storage protein are discussed.     

Application of Multivariate Analysis for the Selection of Candidates for Biological Control Agents

A survey of natural enemies ofSenna obtusifolia(Leguminosae: Cesalpinaceae) was made in 46 localities in Brazil. Twenty-one preselected insect species were used in a multivariate analysis in a search for potential biocontrol agents, based on frequency of occurrence of each species, degree of insect/host association, and damage level. Insect communities were organized in a binary matrix (presence/absence of the species); measures of distance and similarities were based on the Jaccard coefficient, and cluster analysis was then conducted. Construction of a dendogram showed similarities among geographically close localities where phenological stages of sicklepod plants were similar. Analysis of correspondence based on the correlation matrix showed that Eigen values of the three first axes explain only 40.1% of the observed variation. Correlation among the scores produced by species Eigenvectors in each locality on axis 1 and the latitude, altitude, and phenological stage showed that only phenological stage was correlated (r = 0.45,P = 0.02). The results indicate that weather will not be a limiting factor for the establishment of these insect species in an environmental gradient similar to that of the surveyed area (12 to 22° latitude and 6 to 1200 m altitude). Distribution in the ordinal space of axes 1 and 2 showed thatAgrilus oceanicum(Buprestidae),Fundella argentina(Pyralidae),Thyphedanus undulatus(Hesperidae), andPhoebis sennae(Pieridae) are grouped and separated from the others in axis 2, suggesting that these species co-occur with each other. Based on their feeding guilds, multiple introduction of these species can be considered. Multivariate analysis showed potential to be used as an additional tool to help in the selection of candidates for biocontrol agents.     

Effect of culture conditions on the NADH/NAD ratio and total amounts of NAD(H) in chemostat cultures of Enterococcus faecalis NCTC 775

Abstract Enterococcus faecalis was grown in chemostat culture on various energy sources at dilution rates ranging from 0.05 h⁻¹ to 0.5 h⁻¹, under both aerobic and anaerobic conditions. NADH/NAD ratios and total nicotinamide adenine dinucleotide pool size (NAD(H)) were determined. It was found that the NADH/NAD ratio was controlled by the steady state product concentrations rather than by the degree of reduction of the energy source. Highest ratios were observed when NADH was reoxidized via ethanol formation, whereas in aerobic cultures, in which predominantly acetate was produced and oxidation of NADH occurred via the NADH oxidase, ratios were lowest. Addition of ethanol to the medium resulted in an increase of the NADH/NAD ratio, both aerobically and anaerobically. The total amount of NAD(H) was found to be influenced by the culture conditions. Under anaerobic conditions, the NADH oxidation (NAD reduction) rate appeared to correlate with the total amount of nicotinamide nucleotides. In contrast, no effect of the culture conditions on the total amount of NAD(H) was observed in aerobically grown cells.     

Antinociceptive,anti-inflammatory and antipyretic effects of 1.5-diphenyl-1H-Pyrazole-3-carbohydrazide,a new heterocyclic pyrazole derivative

Aims

Heterocyclic pyrazole derivative has been described for the treatment of pain and inflammatory diseases. This study evaluated the in vivo, antinociceptive, anti-inflammatory and antipyretic effects of 1.5-diphenyl-1H-Pyrazole-3-carbohydrazide (1.5-DHP) and the in vivo or in vitro mechanism of action.

Main methods

Acetic acid-induced writhing, hot-plate and formalin-induced nociception tests were used to evaluate the antinociceptive effect, while the rota-rod test was used to assess the motor activity. Croton oil-induced ear edema and carrageenan-induced peritonitis tests were used to investigate the anti-inflammatory effect of 1.5-DHP. The antipyretic effect was assessed using the LPS-induced fever model. The mechanism of action was evaluated by PGE₂ and TNF-α measurement and cyclooxygenase inhibition assay.

Key findings

Oral administration (p.o.) of 1.5-DHP (1, 3, 10 mg/kg) caused a dose-related inhibition of the acetic acid-induced writhing, however the highest dose was not effective on the hot-plate and rota-rod. In the formalin-induced nociception, 1.5-DHP (10 mg/kg, p.o.) inhibited only the late phase of nociception. This same dose of 1.5-DHP also reduced the croton oil-induced ear edema. 1.5-DHP (3, 10, 30 mg/kg, p.o.) produced a dose-related reduction of leukocyte migration on the carrageenan-induced peritonitis. 1.5-DHP (60 mg/kg, p.o.) reduced the fever and the increase of PGE₂ concentration in the cerebrospinal fluid induced by LPS. 1.5-DHP inhibited both COXs in vitro. Finally, 1.5-DHP (10 mg/kg, p.o.) reduced the TNF-α concentration in peritoneal exudates after carrageenan injection.

Significance

These results indicate that 1.5-DHP produces anti-inflammatory, antinociceptive and antipyretic effects by PGE₂ synthesis reduction through COX-1/COX-2 inhibition and by TNF-α synthesis/release inhibition.