Extraction,purification and characterization of galactomannans from non-traditional sources

This work presents a methodology for the extraction of galactomannans from seeds of four different species of Leguminosae (Adenanthera pavonina, Caesalpinia pulcherrima, Gleditsia triacanthos and Sophora japonica) to be used e.g. in the food and biomedical industries. The galactomannans were obtained by aqueous extraction followed by a precipitation with ethanol. This methodology is simpler and easier to perform than other existing extraction and purification methodologies, and because it avoids the use of organic solvents (other than ethanol), it is able to generate food grade substances and is environmentally friendlier. The yield of extraction in different stages of the process, monosaccharide composition, as well as physical and chemical parameters of the isolated galactomannans were determined and compared with previously published results. The mannose/galactose ratio of the extracted galactomannans ranged from 1.35 (A. pavonina) to 5.75 (S. japonica). The intrinsic viscosity ranged from 11.34 dL/g (C. pulcherrima) to 8.74 dL/g (S. japonica), while the viscosity average molecular mass ranged between 1.81 × 10⁶ Da and 1.17 × 10⁶ Da (A. pavonina > C. pulcherrima > G. triacanthos > S. japonica). The results confirm the suitability of the extraction and purification procedure to obtain galactomannans from non-traditional sources.     

Antimicrobial peptides: clinical relevance and therapeutic implications

Antimicrobial peptides (AMPs) are molecules that provide protection against environmental pathogens, acting against a large number of microorganisms, including bacteria, fungi, yeast, virus and others. Two major groups of antimicrobial peptides are found in humans: cathelicidins and defensins. Recently, several studies have furnished information that besides their role in infection diseases, antimicrobial peptides play a role in diseases as diverse as inflammatory disorders, autoimmunity and cancer. Here, we discuss the role of antimicrobial peptides and vitamin D have in such complex diseases and propose their use should be more explored in the diagnosis and treatment of such conditions.     

Computational studies on class I ribonucleotide reductase: understanding the mechanisms of action and inhibition of a cornerstone enzyme for the treatment of cancer

This review provides a synthesis of recent work, using computational methods, on the action and inhibition mechanisms of class I ribonucleotide reductase (RNR). This enzyme catalyzes the rate-limiting step of the pathway for the synthesis of DNA monomers and, therefore, has long been regarded as an important target for therapies aiming to control pathologies that depend strongly on DNA replication. In fact, over the last years, several molecules, which are able to impair RNR activity by different mechanisms, have been applied effectively in anti-cancer, anti-viral and anti-parasite therapies. A better understanding of the chemical mechanisms involved in normal catalysis and in inhibition of the enzyme is important for the rational design of more specific and effective inhibitor compounds. To achieve this goal, computational methods, particularly quantum chemical calculations, have been used more and more frequently. The ever-growing capabilities of these methods together with undeniable advantages make it a stimulating area for research purposes.     

Mechanisms involved in the gastroprotective activity of esculin on acute gastric lesions in mice

This work describes the gastroprotective actions of esculin (6,7-dihydroxycoumarin-6-o-glucoside) against indomethacin- or ethanol-induced lesions and verifies the role of nitric oxide, ATP-dependent K⁺ channels, prostaglandins, transient receptor potential vanilloid 1 and antioxidant effects in the gastroprotective mechanism of esculin in the ethanol-induced gastric lesion model. The intragastric administration of esculin at doses of 12.5, 25 and 50 mg/kg was able to protect the gastric mucosa against ethanol (0.2 mL/animal p.o.), and esculin at doses of 25 and 50 mg/kg protected against indomethacin-induced lesions (20 mg/kg p.o.). Administration of l-NAME (10 mg/kg i.p.), glibenclamide (10 mg/kg i.p.) or indomethacin (10 mg/kg p.o.), but not capsazepine (5 mg/kg p.o.), was able to reduce the gastroprotection promoted by esculin (25 mg/kg) on the ethanol-induced lesions. Measurements of nitrite, a NO metabolite, were increased in the group that was pretreated with esculin. In terms of antioxidant activity as a gastroprotective mechanism of esculin, the results show that pre-treatment with esculin decreased the amount of GSH, increased SOD activity, did not interfere with the CAT activity and decreased both the MPO activity and the MDA amount. In conclusion, pre-treatment with esculin confers significant gastroprotective and antioxidant activity and leads to a reduction in gastric injury; the mechanisms underlying these effects include stimulation of endogenous prostaglandins, nitric oxide synthesis, opening of K_ATP channels and reduction of free radicals or modulation of antioxidant enzyme systems.     

Is surface orientation a determinant for colonisation patterns of vagile and sessile macrobenthos on artificial reefs?

In order to examine how substratum colonisation can affect community structure, a 1-year study was conducted at the Faro/Ancao artificial reef (Algarve, Portugal). In the study of hard substratum communities, motile species are usually neglected and only the conspicuous species are taken into account. Therefore, the development of vagile and sessile components of the epibiotic community were analysed separately. Differences between assemblages on horizontal surfaces, but not on vertical surfaces, were detected. Multivariate analysis detected differences in macrobenthic community structure either considering sessile or motile components. However, significant differences were only detected for vagile fauna. Moreover, this study suggests that for hard substratum communities, analysis of the vagile fauna is important and should be taken into account in the functioning of the artificial raft.     

Microbiological,physical–chemical and sensory evaluation of a traditional Brazilian cheese during the ripening process

The ripening process of the traditional Serra do Salitre cheese, a Brazilian Minas cheese variety, was studied on five farms during 60 days. Faecal coliforms decreased and were not detected after ripening for this period. The contamination by coagulase-negative Staphylococcus was reduced at the end of the ripening period only on farms 3 and 4. Staphylococcus aureus was detected only in fresh cheese on farm 5 and decreased in number until it disappeared. No S. aureus was observed in the fresh cheeses from farms 2 and 4, but these were contaminated, probably by the hands of the manipulators, during the ripening process. The humidity decreased and the proteolysis increased during ripening. No correlation of the salt content and the humidity with the degree of proteolysis was observed. The degree of acceptance in the sensory evaluation was higher for cheese that had ripened for 1 and 15 days.     

Mild mitochondrial uncoupling in mice affects energy metabolism, redox balance and longevity

Caloric restriction is the most effective non-genetic intervention to enhance lifespan known to date. A major research interest has been the development of therapeutic strategies capable of promoting the beneficial results of this dietary regimen. In this sense, we propose that compounds that decrease the efficiency of energy conversion, such as mitochondrial uncouplers, can be caloric restriction mimetics. Treatment of mice with low doses of the protonophore 2,4-dinitrophenol promotes enhanced tissue respiratory rates, improved serological glucose, triglyceride and insulin levels, decrease of reactive oxygen species levels and tissue DNA and protein oxidation, as well as reduced body weight. Importantly, 2,4-dinitrophenol-treated animals also presented enhanced longevity. Our results demonstrate that mild mitochondrial uncoupling is a highly effective in vivo antioxidant strategy, and describe the first therapeutic intervention capable of effectively reproducing the physiological, metabolic and lifespan effects of caloric restriction in healthy mammals.