GM1 ganglioside attenuates convulsions and thiobarbituric acid reactive substances production induced by the intrastriatal injection of methylmalonic acid

The effects of the administration of monosialoganglioside (GM1) on methylmalonic acid (MMA)-induced convulsions, production of thiobarbituric acid reactive substances (TBARS) and on the striatal content of ascorbic acid and total non-protein thiol (SH) groups were evaluated in adult male rats. Animals received two intraperitoneal injections of GM1 (50 mg/kg) or saline (0.85% NaCl) spaced 24h apart. Thirty minutes after the second GM1 or saline injection, L-MMA (6 micromol) or NaCl (9 micromol) was injected into the right striatum and the animals were observed for the appearance of convulsions for 15 min. The animals were sacrificed and their striatal content of ascorbic acid, SH groups and TBARS was measured. The effect of GM1 on MMA-induced TBARS production in striatal homogenates was also evaluated in vitro.MMA injection caused convulsions (Sal-MMA: 9.8+/-1.4 episodes, which lasted 271+/-48 s) and increased the striatal content of TBARS (Sal-MMA: 149.0+/-11.5 nmol MDA/g tissue), but did not alter total striatal SH or ascorbic acid contents. GM1 pretreatment decreased MMA-induced convulsions (GM1-MMA: 6.3+/-2.0 episodes, which lasted 115.1+/-42.2s) and TBARS increase (GM1-MMA: 102.4+/-19.5 nmol MDA/g tissue). GM1 pretreatment increased ascorbic acid content of the striata (saline-pretreated: 1514+/-75.9; GM1-pretreated: 1878.6+/-102.8 microg ascorbic acid/mg tissue). MMA increased TBARS production in vitro, and GM1 had no effect on such MMA-induced effect.This study provides evidence that GM1 increases striatal ascorbic acid content and decreases MMA-induced neurotoxicity assessed by behavioral and neurochemical parameters.     

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.     

Stability and folding of the ferredoxin from the hyperthermophilic archaeon Acidianus ambivalens

The ferredoxin from the thermophilic archaeon Acidianus ambivalens is a small monomeric protein containing two iron-sulfur centres, one [3Fe-4S](1+/0) and one [4Fe-4S](2+/1+). It is an intrinsically hyperstable protein, being expressed at the organism's extreme optimal growth temperature: 80 degrees C. Using spectroscopic methods we have investigated the unfolding reaction of the Acidianus ambivalens ferredoxin. No unfolding of the oxidised ferredoxin was observed at pH 7.0, even in the presence of 8 M GuHCl. Upon increasing the pH to 10.0, the unfolding transition showed a midpoint at 6.3 M GuHCl and an unfolding-free energy of 70 kJ mol(-1) in buffer (pH 10) was estimated. Kinetic-unfolding experiments showed that the polypeptide unfolding correlated with rearrangement of the iron-sulfur centres to new ones which had strong absorption maxima at 520 and 610 nm. These new, possibly linear three-iron, clusters were coordinated to the unfolded protein but degraded slowly. From thermal experiments in the presence of GuHCl we estimated the melting temperature for the Acidianus ambivalens ferredoxin in buffer (at pH 7) to be 122 degrees C. Possible structural properties that contribute to the large thermal stability of the Acidianus ambivalens ferredoxin are discussed using a three-dimensional protein model.     

Effector-Triggered Immune Response in Arabidopsis thaliana Is a Quantitative Trait

We identified loci responsible for natural variation in Arabidopsis thaliana (Arabidopsis) responses to a bacterial pathogen virulence factor, HopAM1. HopAM1 is a type III effector protein secreted by the virulent Pseudomonas syringae strain Pto DC3000. Delivery of HopAM1 from disarmed Pseudomonas strains leads to local cell death, meristem chlorosis, or both, with varying intensities in different Arabidopsis accessions. These phenotypes are not associated with differences in bacterial growth restriction. We treated the two phenotypes as quantitative traits to identify host loci controlling responses to HopAM1. Genome-wide association (GWA) of 64 Arabidopsis accessions identified independent variants highly correlated with response to each phenotype. Quantitative trait locus (QTL) mapping in a recombinant inbred population between Bur-0 and Col-0 accessions revealed genetic linkage to regions distinct from the top GWA hits. Two major QTL associated with HopAM1-induced cell death were also associated with HopAM1-induced chlorosis. HopAM1-induced changes in Arabidopsis gene expression showed that rapid HopAM1-dependent cell death in Bur-0 is correlated with effector-triggered immune responses. Studies of the effect of mutations in known plant immune system genes showed, surprisingly, that both cell death and chlorosis phenotypes are enhanced by loss of EDS1, a regulatory hub in the plant immune-signaling network. Our results reveal complex genetic architecture for response to this particular type III virulence effector, in contrast to the typical monogenic control of cell death and disease resistance triggered by most type III effectors.     

Famine Foods of Brazil’s Seasonal Dry Forests: Ethnobotanical and Nutritional Aspects

Famine Foods of Brazil’s Seasonal Dry Forests: Ethnobotanical and Nutritional Aspects. Famine foods are used by people in times of food scarcity. Although the northeast of Brazil regularly faces periods of drought that cause a shortage of traditional foods, the use of famine foods is insufficiently recorded. The purpose of this study was to record the knowledge of famine food in two rural Caatinga communities, Carão and Cachoeira, in the states of Pernambuco and Paraiba, respectively, and to determine the chemical composition of the major famine foods utilized. The ethnobotanical aspect was divided into two stages: free lists and semistructured interviews. Based on the interviews, the main famine foods known by communities were selected for nutritional analysis. The study revealed that certain foods are used by communities only in times of shortages. Carão showed a higher species richness than Cachoeira, but the food knowledge was more widespread among the interviewees in Cachoeira. In Carão, the main species mentioned were Dioclea grandiflora and Manihot dichotoma, whereas in Cachoeira, Encholirium spectabile and Pilosocereus gounellei were the major species indicated. The species examined had a high carbohydrate content, especially D. grandiflora, Manihot glaziovii, and M. dichotoma, and could be used for complementary feeding of the population if adverse effects could be minimized. Mandevilla tenuiflora is indicated for future studies of potential agro-industrial applications and the beneficial aspects of its root, which could represent an alternative source of income for the population.     

Plant and Bird Presence Strongly Influences the Microbial Communities in Soils of Admiralty Bay,Maritime Antarctica

Understanding the environmental factors that shape microbial communities is crucial, especially in extreme environments, like Antarctica. Two main forces were reported to influence Antarctic soil microbes: birds and plants. Both birds and plants are currently undergoing relatively large changes in their distribution and abundance due to global warming. However, we need to clearly understand the relationship between plants, birds and soil microorganisms. We therefore collected rhizosphere and bulk soils from six different sampling sites subjected to different levels of bird influence and colonized by Colobanthus quitensis and Deschampsia antarctica in Admiralty Bay, King George Island, Maritime Antarctic. Microarray and qPCR assays targeting 16S rRNA genes of specific taxa were used to assess microbial community structure, composition and abundance and analyzed with a range of soil physico-chemical parameters. The results indicated significant rhizosphere effects in four out of the six sites, including areas with different levels of bird influence. Acidobacteria were significantly more abundant in soils with little bird influence (low nitrogen) and in bulk soil. In contrast, Actinobacteria were significantly more abundant in the rhizosphere of both plant species. At two of the sampling sites under strong bird influence (penguin colonies), Firmicutes were significantly more abundant in D. antarctica rhizosphere but not in C. quitensis rhizosphere. The Firmicutes were also positively and significantly correlated to the nitrogen concentrations in the soil. We conclude that the microbial communities in Antarctic soils are driven both by bird and plants, and that the effect is taxa-specific.     

Crystal structure of the lectin of Camptosema pedicellatum: implications of a conservative substitution at the hydrophobic subsite

Lectins have been used as models for studies of the molecular basis of protein-carbohydrate interaction and specificity by deciphering codes present in the glycan structures. The purpose of the present study was to purify and solve the complete primary and crystal structure of the lectin of Camptosema pedicellatum (CPL) complexed with 5-bromo-4-chloro-3-indolyl-α-d-mannose (X-Man) using tandem mass spectrometry. CPL was purified by single-step affinity chromatography. Mass spectrometry findings revealed that purified CPL features a combination of chains weighing 25,298 ± 2 (α-chain), 12,835 ± 2 (β-chain) and 12,481 ± 2 Da (γ-chain). The solved crystal structure of CPL features a conservative mutation in the hydrophobic subsite, a constituent of the carbohydrate recognition domain (CRD), indicating the relevance of hydrophobic interactions in the establishment of interactions with carbohydrates. The substitution and the analysis of the interactions with X-Man also revealed that the hydrophobic effect caused by a minor change in the hydrophobic subsite interferes in the formation of H-bonds due to the reorientation of the indolyl group in the CRD.     

Bioremediation of an Iron-Rich Mine Effluent by Lemna minor

Contamination of water resources by mine effluents is a serious environmental problem. In a old coal mine, in the north of Portugal (São Pedro da Cova, Gondomar), forty years after the activity has ended, a neutral mine drainage, rich in iron (FE) it stills being produced and it is continuously released in local streams (Ribeiro de Murta e Rio Ferreira) and in surrounding lands.The species Lemna minor has been shown to be a good model for ecotoxicological studies and it also has the capacity to bioaccumulate metals.The work aimed test the potential of the species L. minor to remediate this mine effluent, through the bioaccumulation of Fe, under greenhouse experiments and, at the same time, evaluate the time required to the maximum removal of Fe. The results have shown that L. minor was able to grow and develop in the Fe-rich effluent and bioaccumulating this element. Throughout the 21 days of testing it was found that there was a meaningful increase in the biomass of L. minor both in the contaminated and in the non-contaminated waters. It was also found that bioaccumulation of Fe (iron) occurred mainly during the first 7 days of testing. It was found that L. minor has potential for the bioremediation of effluents rich in iron.