Sensitivity of chondrocytes of growing cartilage to reactive oxygen species

Vascular invasion of calcified cartilage, during endochondral ossification, is initiated and sustained by invasive cells (endothelial cells and macrophages) which degrade the tissue by releasing lytic enzymes. Concurrently, reactive oxygen species (ROS) are also released by these cells and we hypothesize that ROS also contribute to the degradation of the tissue. As a preliminary approach to this problem, the antioxidant activities and the effect of ROS on hypertrophic cartilage and chondrocytes (HCs) were investigated. Compared to resting or articular chondrocytes, HCs exhibited higher catalase but lower SOD specific activities and lower PHGPx concentration, thus revealing a defence activity specific against H₂O₂. Moreover, dose-dependent depletion of ATP occurred after few minutes of exposure to ROS, and a long-term treatment (16 h incubation with ROS) promoted the release of LDH activity and a significant variation of the poly- to mono-unsaturated fatty acid ratio. Finally, the incubation of HCs with low ROS doses induced the release of sedimentable alkaline phosphatase activity (matrix vesicles). How the obtained results fit the in vivo occurring events is discussed.     

Cost-Effectiveness Analysis of Optimal Control Measures for Tuberculosis

We propose and analyze an optimal control problem where the control system is a mathematical model for tuberculosis that considers reinfection. The control functions represent the fraction of early latent and persistent latent individuals that are treated. Our aim was to study how these control measures should be implemented, for a certain time period, in order to reduce the number of active infected individuals, while minimizing the interventions implementation costs. The optimal intervention is compared along different epidemiological scenarios, by varying the transmission coefficient. The impact of variation of the risk of reinfection, as a result of acquired immunity to a previous infection for treated individuals on the optimal controls and associated solutions, is analyzed. A cost-effectiveness analysis is done, to compare the application of each one of the control measures, separately or in combination.     

Plasmodium simium/Plasmodium vivax infections in southern brown howler monkeys from the Atlantic Forest

Blood infection by the simian parasite, Plasmodium simium, was identified in captive (n = 45, 4.4%) and in wild Alouatta clamitans monkeys (n = 20, 35%) from the Atlantic Forest of southern Brazil. A single malaria infection was symptomatic and the monkey presented clinical and haematological alterations. A high frequency of Plasmodium vivax-specific antibodies was detected among these monkeys, with 87% of the monkeys testing positive against P. vivax antigens. These findings highlight the possibility of malaria as a zoonosis in the remaining Atlantic Forest and its impact on the epidemiology of the disease.     

The Duffy binding protein as a key target for a Plasmodium vivax vaccine: lessons from the Brazilian Amazon

Plasmodium vivax infects human erythrocytes through a major pathway that requires interaction between an apical parasite protein, the Duffy binding protein (PvDBP) and its receptor on reticulocytes, the Duffy antigen/receptor for chemokines (DARC). The importance of the interaction between PvDBP (region II, DBPII) and DARC to P. vivax infection has motivated our malaria research group at Oswaldo Cruz Foundation (state of Minas Gerais, Brazil) to conduct a number of immunoepidemiological studies to characterise the naturally acquired immunity to PvDBP in populations living in the Amazon rainforest. In this review, we provide an update on the immunology and molecular epidemiology of PvDBP in the Brazilian Amazon - an area of markedly unstable malaria transmission - and compare it with data from other parts of Latin America, as well as Asia and Oceania.     

Comparative proteomic analysis of four biotechnological strains Lactococcus lactis through label-free quantitative proteomics

Lactococcus lactis is a bacteria with high biotechnological potential, where is frequently used in the amino acid production and production of fermented dairy products, as well as drug delivery systems and mucosal vaccine vector. The knowledge of a functional core proteome is important extremely for both fundamental understanding of cell functions and for synthetic biology applications. In this study, we characterized the L. lacits proteome from proteomic analysis of four biotechnological strains L. lactis: L. lactis subsp. lactis NCDO2118, L. lactis subsp. lactis IL1403, L. lactis subsp. cremoris NZ9000 and L. lactis subsp. cremoris MG1363. Our label-free quantitative proteomic analysis of the whole bacterial lysates from each strains resulted in the characterization of the L. lactis core proteome that was composed by 586 proteins, which might contribute to resistance of this bacterium to different stress conditions as well as involved in the probiotic characteristic of L. lactis. Kegg enrichment analysis shows that ribosome, metabolic pathways, pyruvate metabolism and microbial metabolism in diverse environments were the most enriched. According to our quantitative proteomic analysis, proteins related to translation process were the more abundant in the core proteome, which represent an important step in the synthetic biology. In addition, we identified a subset of conserved proteins that are exclusive of the L. lactis subsp. cremoris or L. lactis subsp. lactis, which some are related to metabolic pathway exclusive. Regarding specific proteome of NCDO2118, we detected ‘strain-specific proteins’. Finally, proteogenomics analysis allows the identification of proteins, which were not previously annotated in IL1403 and MG1363. The results obtained in this study allowed to increase our knowledge about the biology of L. lactis, which contributes to the implementation of strategies that make it possible to increase the biotechnological potential of this bacterium.     

A new “sudden fright paradigm” to explore the role of (epi)genetic modulations of the DAT gene in fear-induced avoidance behavior

Alterations in dopamine (DA) reuptake are involved in several psychiatric disorders whose symptoms can be investigated in knock out rats for the DA transporter (DAT-KO). Recent studies evidenced the role of epigenetic DAT modulation in depressive-like behavior. Accordingly, we used heterozygous (HET) rats born from both HET parents (termed MIX-HET), compared to HET rats born from WT-mother and KO-father (MAT-HET), implementing the role of maternal care on DAT modulation. We developed a “sudden fright” paradigm (based on dark-light test) to study reaction to fearful inputs in the DAT-KO, MAT-HET, MIX-HET, and WT groups. Rats could freely explore the whole 3-chambers apparatus; then, they were gently confined in one room where they experienced the fright; finally, they could freely move again. As expected, after the fearful stimulus only MAT-HET rats showed a different behavior consisting of avoidance towards the fear-associated chamber, compared to WT rats. Furthermore, ex-vivo immuno-fluorescence reveals higher prefrontal DAT levels in MAT-HET compared to MIX-HET and WT rats. Immuno-fluorescence shows also a different histone deacetylase (HDAC) enzymes concentration. Since HDAC concentration could modulate gene expression, within MAT-HET fore brain, the enhanced expression of DAT could well impair the corticostriatal-thalamic circuit, thus causing aberrant avoidance behavior (observed only in MAT-HET rats). DAT expression seems to be linked to a simply different breeding condition, which points to a reduced care by HET dams for epigenetic regulation. This could imply significant prefronto-cortical influences onto the emotional processes: hence an excessively frightful response, even to mild stressful agents, may draw developmental trajectories toward anxious and depressed-like behavior.     

Spontaneous sister chromatid exchange and chromosome aberration frequency in humans: the familial effect.

The possible effects of environmental and genetic factors on spontaneous frequencies of sister chromatid exchanges (SCEs) and cells with chromosome aberrations (CAs) in human lymphocytes were investigated by analysing 177 completed families (mother, father and at least one child). After removing the effects of methodological, biological and life-style factors by the use of multifactor analysis of variance (MANOVA), SCEs and CAs residuals were analysed by simple correlation analysis and principal component analysis. SCEs and CAs inter-familiar variability was higher than that found within families. A significant correlation was found between the average SCE frequencies shared by parents (the so-called 'midpoint parents', or 'midparent') and offspring (linear slope b=0.26+/-0.07, p<0.05), but also between mother and father (b=0.23+/-0.11, p<0.05) suggesting the presence of an effective environmental factor. The midparent-offspring correlation was found to be sustained by the mother-offspring relationship (b=0.28+/-0.08, p<0.05), being the father-offspring correlation not significant (b=0.16+/-0.11, p0.05). Concerning CAs, no statistically significant correlation between parents was found, but the strong relationship between mother and offspring was confirmed (b=0.468+/-0.11, p<0.001). The SCEs correlation between mother vs. offspring disappeared for older offspring (over 23 years old). The obtained findings strongly showed that the genetic make-up is barely detectable in the presence of domestic environment factors which are shown to play the major role in determining the interfamilial variability of SCE and CA in a general population. These results strengthen the suitability of the use of SCEs and CAs analysis in human cytogenetic surveillance for the detection of effective environmental factors.