Biology and phenology of three leaf beetle species (Chrysomelidae) in a montane forest in southeast Brazil

The population phenology of the cassidines, Coptocycla arcuata and Omaspides trichroa, and the chrysomeline, Platyphora axillaris, was studied at Serra dos Órgãos National Park, State of Rio de Janeiro, southeast Brazil. Monthly surveys of larvae and adults were conducted between 2008 and 2011 at approximately 1000 m altitude on their respective host plants, Cordia polycephala (Boraginaceae), Ipomoea philomega (Convolvulaceae) and Solanum scuticum (Solanaceae). This is the first observation of larviparity and host record for Platyphora axillaris. Although having different life history traits, all species showed similar phenologies. They were abundant from October to March, months of high temperatures and intense rainfall, with two distinct reproductive peaks in the same season. Abundance dropped abruptly during the coldest and driest months, from May to August. Frequently none of these species were recorded during June and July. This phenological pattern is similar to other Chrysomelidae living in subtropical areas of Brazil. Temperature and rainfall appear to be the major factors influencing the fluctuation of these three species.     

Subacute calorie restriction and rapamycin discordantly alter mouse liver proteome homeostasis and reverse aging effects

Calorie restriction (CR) and rapamycin (RP) extend lifespan and improve health across model organisms. Both treatments inhibit mammalian target of rapamycin (mTOR) signaling, a conserved longevity pathway and a key regulator of protein homeostasis, yet their effects on proteome homeostasis are relatively unknown. To comprehensively study the effects of aging, CR, and RP on protein homeostasis, we performed the first simultaneous measurement of mRNA translation, protein turnover, and abundance in livers of young (3 month) and old (25 month) mice subjected to 10‐week RP or 40% CR. Protein abundance and turnover were measured in vivo using ²H₃–leucine heavy isotope labeling followed by LC‐MS/MS, and translation was assessed by polysome profiling. We observed 35–60% increased protein half‐lives after CR and 15% increased half‐lives after RP compared to age‐matched controls. Surprisingly, the effects of RP and CR on protein turnover and abundance differed greatly between canonical pathways, with opposite effects in mitochondrial (mt) dysfunction and eIF2 signaling pathways. CR most closely recapitulated the young phenotype in the top pathways. Polysome profiles indicated that CR reduced polysome loading while RP increased polysome loading in young and old mice, suggesting distinct mechanisms of reduced protein synthesis. CR and RP both attenuated protein oxidative damage. Our findings collectively suggest that CR and RP extend lifespan in part through the reduction of protein synthetic burden and damage and a concomitant increase in protein quality. However, these results challenge the notion that RP is a faithful CR mimetic and highlight mechanistic differences between the two interventions.     

Adaptive basal phosphorylation of eIF2α is responsible for resistance to cellular stress-induced cell death in Pten-null hepatocytes

The α-subunit of eukaryotic initiation factor 2 (eIF2α) is a key translation regulator that plays an important role in cellular stress responses. In the present study, we investigated how eIF2α phosphorylation can be regulated by a tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) and how such regulation is used by PTEN-deficient hepatocytes to adapt and cope with oxidative stress. We found that eIF2α was hyperphosphorylated when Pten was deleted, and this process was AKT dependent. Consistent with this finding, we found that the Pten-null cells developed resistance to oxidative glutamate and H(2)O(2)-induced cellular toxicity. We showed that the messenger level of CReP (constitutive repressor of eIF2α phosphorylation), a constitutive phosphatase of eIF2α, was downregulated in Pten-null hepatocytes, providing a possible mechanism through which PTEN/AKT pathway regulates eIF2α phosphorylation. Ectopic expression of CReP restored the sensitivity of the Pten mutant hepatocytes to oxidative stress, confirming the functional significance of the downregulated CReP and upregulated phospho-eIF2α in the resistance of Pten mutant hepatocytes to cellular stress. In summary, our study suggested a novel role of PTEN in regulating stress response through modulating the CReP/eIF2α pathway.     

The possible role of L-carnitine on the skeletal muscle of ovariectomized rats

Low muscle strength is observed during the peri-and postmenopausal periods, when the secretion of ovarian hormones is drastically reduced. It is also a predictive of adverse health events as well as incident mobility limitation and disability. The objective of the present study is to study the biochemical and the histological changes in the skeletal muscle of premature menopause-induced rats and the possible protective role of L-carnitine. Ovariectomized (OVX) rats were gavaged with L-carnitine (100 mg/kg) daily for 60 days starting from the second post-operative day. Serum levels of estradiol and markers of skeletal muscle damage (creatine kinase and lactic dehydrogenase activities) were determined. Light and electron microscopic study of the quadriceps femoris muscle (QFM) specimens were done. OVX rats showed significant decrease in the serum estradiol level with significant increase the markers for skeletal muscle damage. Histopathological examination of the QFM showed degenerated myofibers, apoptotic changes and compensatory hypertrophy. Degenerated mitochondria, multiple lysosomes and lipid droplets among the damaged myofibrils were also noticed. L-carnitine administration to the OVX rats resulted in non-significant change in the serum estradiol level with significant attenuation of skeletal muscle damage either biochemically or histopathologically. In conclusion, L-carnitine administration recovered muscle degeneration after ovariectomy. This finding suggested that L-carnitine could be recommended in the management of post-menopausal myopathy.     

Retracing micro-epidemics of Chagas disease using epicenter regression

Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al espa?ol disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1.     

Optimization of fibrolytic enzyme production by Aspergillus japonicus C03 with potential application in ruminant feed and their effects on tropical forages hydrolysis

Fibrolytic enzyme production by Aspergillus japonicus C03 was optimized in a medium containing agro-industrial wastes, supplemented with peptone and yeast extract. A 2³ full factorial composite and response surface methodology were used to design the experiments and analysis of results. Tropical forages were hydrolyzed by A. japonicus C03 enzymatic extract in different levels, and they were also tested as enzymatic substrate. Optimal production to xylanase was obtained with soybean bran added to crushed corncob (1:3), 0.01% peptone, and 0.2% yeast extract, initial pH 5.0, at 30 °C under static conditions for 5 days of incubation. Optimal endoglucanase production was obtained with wheat bran added to sugarcane bagasse (3:1), 0.01% peptone, and 0.2% yeast extract, initial pH 4.0, at 30 °C, for 6 days, under static conditions. Addition of nitrogen sources as ammonium salts either inhibited or did not influence xylanase production. This enzymatic extract had a good result on tropical forage hydrolyzes and showed better performance in the Brachiaria genera, due to their low cell wall lignin quantity. These results represent a step forward toward the use of low-cost agricultural residues for the production of valuable enzymes with potential application in animal feed, using fermentation conditions.     

Copper exposure effects on yeast mitochondrial proteome

Mitochondria play an important role on the entire cellular copper homeostatic mechanisms. Alteration of cellular copper levels may thus influence mitochondrial proteome and its investigation represents an important contribution to the general understanding of copper-related cellular effects. In these study we have performed an organelle targeted proteomic investigation focusing our attention on the effect of non-lethal 1mM copper concentration on Saccharomyces cerevisiae mitochondrial proteome. Functional copper effects on yeast mitochondrial proteome were evaluated by using both 2D electrophoresis (2-DE) and liquid chromatography coupled with tandem mass spectrometry. Proteomic data have been then analyzed by different unsupervised meta-analysis approaches that highlight the impairment of mitochondrial functions and the activation of oxidative stress response. Interestingly, our data have shown that stress response generated by 1mM copper treatment determines the activation of S. cerevisiae survival pathway. To investigate these findings we have treated yeast cells responsiveness to copper with hydrogen peroxide and observed a protective role of this metal. These results are suggestive of a copper role in the protection from oxidative stress possibly due to the activation of mechanisms involved in cellular survival and growth.     

Cardiovascular Disease Risk of Abdominal Obesity vs. Metabolic Abnormalities

It remains unclear whether abdominal obesity increases cardiovascular disease (CVD) risk independent of the metabolic abnormalities that often accompany it. Therefore, the objective of this study was to evaluate the independent effects of abdominal obesity vs. metabolic syndrome and diabetes on the risk for incident coronary heart disease (CHD) and stroke. The Framingham Offspring, Atherosclerosis Risk in Communities, and Cardiovascular Health studies were pooled to assess the independent effects of abdominal obesity (waist circumference >102 cm for men and >88 cm for women) vs. metabolic syndrome (excluding the waist circumference criterion) and diabetes on risk for incident CHD and stroke in 20,298 men and women aged ≥45 years. The average follow‐up was 8.3 (s.d. 1.9) years. There were 1,766 CVD events. After adjustment for demographic factors, smoking, alcohol intake, number of metabolic syndrome components, and diabetes, abdominal obesity was not significantly associated with an increased risk of CVD (hazard ratio (HR) (95% confidence interval): 1.09 (0.98, 1.20)). However, after adjustment for demographics, smoking, alcohol intake, and abdominal obesity, having 1–2 metabolic syndrome components, the metabolic syndrome and diabetes were each associated with a significantly increased risk of CVD (2.12 (1.80, 2.50), 2.82 (1.92, 4.12), and 5.33 (3.37, 8.41), respectively). Although abdominal obesity is an important clinical tool for identification of individuals likely to possess metabolic abnormalities, these data suggest that the metabolic syndrome and diabetes are considerably more important prognostic indicators of CVD risk.     

In-cell NMR in E. coli to monitor maturation steps of hSOD1

In-cell NMR allows characterizing the folding state of a protein as well as posttranslational events at molecular level, in the cellular context. Here, the initial maturation steps of human copper, zinc superoxide dismutase 1 are characterized in the E. coli cytoplasm by in-cell NMR: from the apo protein, which is partially unfolded, to the zinc binding which causes its final quaternary structure. The protein selectively binds only one zinc ion, whereas in vitro also the copper site binds a non-physiological zinc ion. However, no intramolecular disulfide bridge formation occurs, nor copper uptake, suggesting the need of a specific chaperone for those purposes.