Domestic,peridomestic and wild hosts in the transmission of Trypanosoma cruzi in the Caatinga area colonised by Triatoma brasiliensis

The role played by different mammal species in the maintenance of Trypanosoma cruzi is not constant and varies in time and place. This study aimed to characterise the importance of domestic, wild and peridomestic hosts in the transmission of T. cruzi in Tauá, state of Ceará, Caatinga area, Brazil, with an emphasis on those environments colonised by Triatoma brasiliensis. Direct parasitological examinations were performed on insects and mammals, serologic tests were performed on household and outdoor mammals and multiplex polymerase chain reaction was used on wild mammals. Cytochrome b was used as a food source for wild insects. The serum prevalence in dogs was 38% (20/53), while in pigs it was 6% (2/34). The percentages of the most abundantly infected wild animals were as follows: Thrichomys laurentius 74% (83/112) and Kerodon rupestris 10% (11/112). Of the 749 triatomines collected in the household research, 49.3% (369/749) were positive for T. brasiliensis, while 6.8% were infected with T. cruzi (25/369). In captured animals, T. brasiliensis shares a natural environment with T. laurentius, K. rupestris, Didelphis albiventris, Monodelphis domestica, Galea spixii, Wiedomys pyrrhorhinos, Conepatus semistriatus and Mus musculus. In animals identified via their food source, T. brasiliensis shares a natural environment with G. spixii, K. rupestris, Capra hircus, Gallus gallus, Tropidurus oreadicus and Tupinambis merianae. The high prevalence of T. cruzi in household and peridomiciliar animals reinforces the narrow relationship between the enzootic cycle and humans in environments with T. brasiliensis and characterises it as ubiquitous.     

Caloric restriction reveals a metabolomic and lipidomic signature in liver of male mice

Lipid composition, particularly membrane unsaturation, has been proposed as being a lifespan determinant, but it is currently unknown whether caloric restriction (CR), an accepted life‐extending intervention, affects cellular lipid profiles. In this study, we employ a liquid chromatography quadrupole time‐of‐flight‐based methodology to demonstrate that CR in the liver of male C57BL/6 mice: (i) induces marked changes in the cellular lipidome, (ii) specifically reduces levels of a phospholipid peroxidation product, 1‐palmitoyl‐2‐glutaryl‐sn‐glycero‐3‐phosphatidylcholine, (iii) alters cellular phosphoethanolamine and triglyceride distributional profiles, (iv) affects mitochondrial electron transport chain complexes, increasing complex II and decreasing complex III and (v) is associated with specific changes in liver metabolic pathways. These data demonstrate that CR induces a specific lipidome and metabolome reprogramming event in mouse liver which is associated with lower protein oxidative damage, as assessed by mass spectrometry‐based measurements. Such changes may be critical to the increased lifespan and healthspan observed in C57BL/6 mice following CR.     

Mitochondrial DNA Mutations Induce Mitochondrial Dysfunction,Apoptosis and Sarcopenia in Skeletal Muscle of Mitochondrial DNA Mutator Mice

Background

Aging results in a progressive loss of skeletal muscle, a condition known as sarcopenia. Mitochondrial DNA (mtDNA) mutations accumulate with aging in skeletal muscle and correlate with muscle loss, although no causal relationship has been established.

Methodology/Principal Findings

We investigated the relationship between mtDNA mutations and sarcopenia at the gene expression and biochemical levels using a mouse model that expresses a proofreading-deficient version (D257A) of the mitochondrial DNA Polymerase γ, resulting in increased spontaneous mtDNA mutation rates. Gene expression profiling of D257A mice followed by Parametric Analysis of Gene Set Enrichment (PAGE) indicates that the D257A mutation is associated with a profound downregulation of gene sets associated with mitochondrial function. At the biochemical level, sarcopenia in D257A mice is associated with a marked reduction (35–50%) in the content of electron transport chain (ETC) complexes I, III and IV, all of which are partly encoded by mtDNA. D257A mice display impaired mitochondrial bioenergetics associated with compromised state-3 respiration, lower ATP content and a resulting decrease in mitochondrial membrane potential (Δψ_m). Surprisingly, mitochondrial dysfunction was not accompanied by an increase in mitochondrial reactive oxygen species (ROS) production or oxidative damage.

Conclusions/Significance

These findings demonstrate that mutations in mtDNA can be causal in sarcopenia by affecting the assembly of functional ETC complexes, the lack of which provokes a decrease in oxidative phosphorylation, without an increase in oxidative stress, and ultimately, skeletal muscle apoptosis and sarcopenia.     

Effects of fasting on oxidative stress in rat liver mitochondria

While moderate caloric restriction has beneficial effects on animal health state, fasting may be harmful. The present investigation was designed to test how fasting affects oxidative stress, and to find out whether the effects are opposite to those previously found in caloric restriction studies. We have focused on one of the main determinants of aging rate: the rate of mitochondrial free radical generation. Different parameters related to lipid and protein oxidative damage were also analyzed. Liver mitochondria from rats subjected to 72 h of fasting leaked more electrons per unit of O₂ consumed at complex III, than mitochondria from ad libitum fed rats. This increased leak led to a higher free radical generation under state 3 respiration using succinate as substrate. Regarding lipids, fasting altered fatty acid composition of hepatic membranes, increasing the double bond and the peroxidizability indexes. In accordance with this, we observed that hepatic membranes from the fasted animals were more sensitive to lipid peroxidation. Hepatic protein oxidative damage was also increased in fasted rats. Thus, the levels of oxidative modifications, produced either indirectly by reactive carbonyl compounds (N^epsilon- malondialdehyde-lysine), or directly through amino acid oxidation (glutamic and aminoadipic semialdehydes) were elevated due to the fasting treatment in both liver tissue and liver mitochondria. The current study shows that severe food deprivation increases oxidative stress in rat liver, at least in part, by increasing mitochondrial free radical generation during state 3 respiration and by increasing the sensitivity of hepatic membranes to oxidative damage, suggesting that fasting and caloric restriction have different effects on liver mitochondrial oxidative stress.     

Seasonal variation and analgesic properties of different parts from Curcuma zedoaria Roscoe (Zingiberaceae) grown in Brazil

This work describes the seasonal variation of curcumenol (1) and dihydrocurdione (2), two active terpenoids from different parts (roots, mother rhizome and rugous rhizome) of Curcuma zedoaria grown in Brazil. The analysis was carried out by high resolution gas chromatography, using external standards for determination. The results showed that both terpenoids are present in all the parts studied. However, C. zedoaria exhibited about three times more terpenoids in the mother rhizome in autumn than in other parts and seasons studied. The antinociceptive activity of the dichloromethane extracts from different parts and collected in different seasons was studied using the acetic acid-induced abdominal constriction model in mice. The extracts obtained from mother rhizome collected in autumn and winter at doses of 10 mg/kg body weight, i.p., caused considerable antinociceptive activity inhibiting 91.1 and 93.4% of the abdominal constrictions, respectively, whereas compounds 1 and 2 caused inhibitions of 64.0 and 46.0%, respectively. These results confirm that both compounds contribute to explain the antinociceptive effect of the plant but suggest that other compounds are also acting as analgesics.     

Depletion of oxidative and endoplasmic reticulum stress regulators in Pick disease

Both oxidative and endoplasmic reticulum (ER) stress is associated with multiple neurodegenerative, age-related diseases. The rare disorder Pick disease (PiD) shares some pathological hallmarks of other neurodegenerative diseases that may be related to oxidative stress. Importantly, activation of an ER stress response, which is also involved in aging, has not yet been investigated in PiD. In this study, we assessed the implication of ER stress associated with oxidative stress in PiD as a potential mechanism involved in its pathogenesis. Samples from morphologically affected frontal cortex and apparently pathologically preserved occipital cortex showed region-dependent increases in different protein oxidative damage pathways. The oxidative modifications targeted antioxidant enzymes, proteases, heat shock proteins, and synaptic proteins. These effects were associated with compromised proteasomal function and ER stress in frontal cortex samples. In addition, we observed a depletion in ER chaperones (glucose-regulated proteins Grp78/BiP and glucose-regulated protein 94) and differences in tissue content and distribution of nuclear factor-erythroid 2 p45-related respiratory 2, required for cell survival during the unfolded protein response. These results demonstrate increased region-specific protein oxidative damage in PiD, with proteasomal alteration and dysfunctional ER stress response. We suggest this was caused by complete and specific depletion of Grp78/BiP, contributing to the pathophysiology of this neurodegenerative disease.     

Dietary antioxidants interfere with Amplex Red-coupled-fluorescence assays

Oxidation of Amplex Red by hydrogen peroxide in the presence of horseradish peroxidase (HRP) gives rise to an intensely colour product, resorufin. This reaction has been frequently employed for measurements based on enzyme-coupled reactions that detect hydrogen peroxide as a final reaction product. In the current study, we show that the presence of dietary antioxidants at biological concentrations in the reaction medium produced interferences in the Amplex Red/HRP catalyzed reaction that result in an over quantification of the hydrogen peroxide produced. The interference observed showed a dose-dependent manner, and a possible mechanism of interaction of dietary antioxidants with HRP in the Amplex Red-coupled-fluorescent assay is proposed.     

In vitro plant regeneration of Aster scaber via somatic embryogenesis

We established an in vitro plant regeneration system via somatic embryogenesis of Aster scaber, an important source of various biologically active phytochemicals. We examined the callus induction and embryogenic capacities of three explants, including leaves, petioles, and roots, on 25 different media containing different combinations of α-naphthalene acetic acid (NAA) and 6-benzyladenine (BA). The optimum concentrations of NAA and BA for the production of embryogenic calli were 5.0 μM and 0.05 μM, respectively. Media containing higher concentrations of auxin and cytokinin (such as 25 μM NAA and 25 μM BA) were suitable for shoot regeneration, especially for leaf-derived calli, which are the most readily available calli and are highly competent. For root induction from regenerated shoots, supplemental auxin and/or cytokinin did not improve rooting, but instead caused unwanted callus induction or retarded growth of regenerated plants. Therefore, plant growth regulator-free medium was preferable for root induction. Normal plants were successfully obtained from calli under the optimized conditions described above. This is the first report of the complete process of in vitro plant regeneration of A. scaber via somatic embryogenesis.     

Advanced lipoxidation end-products

Chemical and nonenzymatic molecular modifications induced by reactive carbonyl species (RCS) generated by peroxidation of membrane phospholipids acyl chains play a dual role as signaling molecules and as mediators of the aging process. Cytotoxic effects of RCS are due to their capacity to react with cellular constituents, forming advanced lipoxidation end-products (ALEs). Reactive carbonyl compounds are stable and can diffuse within or even escape from the cell and attack targets far from the site of formation. The consequent loss of function and structural integrity of modified biomolecules can have a wide range of downstream functional consequences and may be the cause of subsequent cellular dysfunctions and tissue damage.     

B7-CD28 costimulatory signals control the survival and proliferation of murine and human γδ T cells via IL-2 production

γδ T cells play key nonredundant roles in immunity to infections and tumors. Thus, it is critical to understand the molecular mechanisms responsible for γδ T cell activation and expansion in vivo. In striking contrast to their αβ counterparts, the costimulation requirements of γδ T cells remain poorly understood. Having previously described a role for the TNFR superfamily member CD27, we since screened for other nonredundant costimulatory receptors in γδ T cell activation. We report in this article that the Ig superfamily receptor CD28 (but not its related protein ICOS) is expressed on freshly isolated lymphoid γδ T cells and synergizes with the TCR to induce autocrine IL-2 production that promotes γδ cell survival and proliferation in both mice and humans. Specific gain-of-function and loss-of-function experiments demonstrated a nonredundant function for CD28 interactions with its B7 ligands, B7.1 (CD80) and B7.2 (CD86), both in vitro and in vivo. Thus, γδ cell proliferation was significantly enhanced by CD28 receptor agonists but abrogated by B7 Ab-mediated blockade. Furthermore, γδ cell expansion following Plasmodium infection was severely impaired in mice genetically deficient for CD28. This resulted in the failure to mount both IFN-γ-mediated and IL-17-mediated γδ cell responses, which contrasted with the selective effect of CD27 on IFN-γ-producing γδ cells. Our data collectively show that CD28 signals are required for IL-2-mediated survival and proliferation of both CD27(+) and CD27(-) γδ T cell subsets, thus providing new mechanistic insight for their modulation in disease models.