Metformin Protects Skeletal Muscle from Cardiotoxin Induced Degeneration

The skeletal muscle tissue has a remarkable capacity to regenerate upon injury. Recent studies have suggested that this regenerative process is improved when AMPK is activated. In the muscle of young and old mice a low calorie diet, which activates AMPK, markedly enhances muscle regeneration. Remarkably, intraperitoneal injection of AICAR, an AMPK agonist, improves the structural integrity of muscles of dystrophin-deficient mdx mice. Building on these observations we asked whether metformin, a powerful anti-hyperglycemic drug, which indirectly activates AMPK, affects the response of skeletal muscle to damage. In our conditions, metformin treatment did not significantly influence muscle regeneration. On the other hand we observed that the muscles of metformin treated mice are more resilient to cardiotoxin injury displaying lesser muscle damage. Accordingly myotubes, originated in vitro from differentiated C2C12 myoblast cell line, become more resistant to cardiotoxin damage after pre-incubation with metformin. Our results indicate that metformin limits cardiotoxin damage by protecting myotubes from necrosis. Although the details of the molecular mechanisms underlying the protective effect remain to be elucidated, we report a correlation between the ability of metformin to promote resistance to damage and its capacity to counteract the increment of intracellular calcium levels induced by cardiotoxin treatment. Since increased cytoplasmic calcium concentrations characterize additional muscle pathological conditions, including dystrophies, metformin treatment could prove a valuable strategy to ameliorate the conditions of patients affected by dystrophies.     

Mitochondrial DNA in metazoa: degree of freedom in a frozen event

The mitochondrial genome (mtDNA), due to its peculiar features such as exclusive presence of orthologous genes, uniparental inheritance, lack of recombination, small size and constant gene content, certainly represents a major model system in studies on evolutionary genomics in metazoan. In 800 million years of evolution the gene content of metazoan mitochondrial genomes has remained practically frozen but several evolutionary processes have taken place. These processes, reviewed here, include rearrangements of gene order, changes in base composition and arising of compositional asymmetry between the two strands, variations in the genetic code and evolution of codon usage, lineage-specific nucleotide substitution rates and evolutionary patterns of mtDNA control regions.     

The activity of the plant mitochondrial inner membrane anion channel (PIMAC) of maize populations divergently selected for cold tolerance level is differentially dependent on the growth temperature of seedlings

The activity of the plant inner membrane mitochondrial anion channel (PIMAC) is involved in metabolite shuttles and mitochondrial volume changes and could have a role in plant temperature tolerance. Our objectives were to investigate (i) the occurrence and (ii) the temperature dependence of anion fluxes through PIMAC in mitochondria isolated from seedlings of three maize populations differing in terms of cold tolerance; and (iii) the relationships between the PIMAC activity kinetics and the level of cold tolerance. Populations were the source population (C0) and two populations divergently selected for high (C4H) and low (C4L) cold tolerance. Such divergently selected populations are expected to share most of their genes, with the main exception of those genes controlling cold tolerance. Arrhenius plots of PIMAC chloride fluxes showed a linear temperature dependence when seedlings were grown at 25 or 14°C, whereas a non-linear temperature dependence was found when seedlings were grown at 5°C, with or without acclimation at 14°C. The activation energy and other thermodynamic parameters of PIMAC activity varied depending on temperature treatments during seedling growth. When seedlings were grown at 14 and 5°C with acclimation, PIMAC activity of the C4H population increased, while that of C4L declined, as compared with the activities of seedlings grown at 25°C. These symmetric responses indicate that PIMAC activity changes are associated with genetically determined differences in the cold tolerance level of the investigated populations. We conclude that anion fluxes by PIMAC depend upon changes on growth temperature and are differentially related to the tolerance level of the tested populations.     

Tropane alkaloids from Schizanthus hookeri

Tropine, a pair of diastereoisomeric hygrolines and two new tropane alkaloids; 3α-senecioyloxytropan-6β-ol and 6β-angeloyloxytropan-3α-ol, were isolated from roots of Schizanthus hookeri.     

Oral supplements of vitamin E improve measures of oxidative stress in plasma and reduce oxidative damage to LDL and erythrocytes in β-thalassemia intermedia patients

Fifteen β-thalassemia intermedia patients, not requiring chronic transfusional therapy, were monitored in order to check their antioxidant status, and the lipid oxidation products in plasma, LDL, and erythrocytes before and during a 9-month oral treatment with 600 mg/day vitamin E. The low level of vitamin E, and high level of malondialdehyde in plasma clearly tended to normalize after three months (P<.001), and were quite similar to control after six months. The abnormally low level of vitamin E in LDL and the four times higher than control basal level of conjugated dienes (LDL-CD), were not modified after three months of treatment. Significant changes of LDL-VE (P<.05) and of the basal LDL-CD (P<.001) were evident after six months. LDL-VE was within the normal range after nine months, whereas LDL-CD still appeared twice as higher than control.

Plasma vitamin A, ascorbate, β-carotene, and lycopene increased markedly at the end of the trial (P<.005).

The level of vitamin E in red blood cells was normalized after six months of supplementation. A decrease of the baseline value of conjugated dienes was observed after nine months, although it remained 1.4-fold higher than control. The RBC count and hematocrit appeared higher at the end of the trial (P<.05 and P<.001, respectively). The hemoglobin value did not show variations. A shift to normal of the resistance of erythrocytes to osmotic lysis was observed.

Our findings provide evidence that an oral treatment with vitamin E improves the antioxidant/oxidant balance in plasma, LDL particles, and red blood cells, and counteracts lipid peroxidation processes in β-thalassemia intermedia patients.     

An approach for identifying the influence of carcass type and environmental features on sarcosaprophagous Diptera communities

Summary. Since the entomosarcosaprophagous community is affected by environmental variables, it needs to be studied under different environmental conditions. In addition, because most studies are usually conducted with biomodels rather than human corpses, it is necessary to verify whether or not the type of decomposing animal matter affects the decomposition process itself, as well as the related fauna. For this reason, a study was conducted on the sarcosaprophagous Diptera community in two different environments of the Region of Murcia (SE Spain), using piglet and chicken carcasses, and Schoenly traps as collecting devices. To analyse possible differences regarding faunal composition among samples, a one-way Permutational Multivariate Analysis of Variance (PERMANOVA) was applied. The results indicate significant differences concerning the bait. In this sense, Calliphoridae, Muscidae, Fanniidae and Sarcophagidae families are the main groups responsible for such differences. In terms of environment-related differences, the only species that contribute are those of the dominant families, Calliphoridae and Muscidae.