Antioxidant properties and total phenolic contents of some tropical seaweeds of the Brazilian coast

Many types of macroalgae contain a wide range of bioactive compounds that have antioxidant potential. However, in contrast to terrestrial plants, only a few studies have reported the antioxidant activity of seaweeds. Therefore, extracts from 26 marine macroalgae species from the south and southeast coasts of Brazil were evaluated for their antioxidant activity, using the 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) method and β-carotene/linoleic acid assay, and their total phenolic contents, through Folin–Ciocalteu method. Padina gymnospora, Sargassum vulgare, and Osmundaria obtusiloba presented the highest values of total phenolic content. Using β-carotene bleaching assay, Colpomenia sinuosa, Dictyota sp., Dichotomaria marginata, Ganonema farinosum, and Spyridia clavata presented up to 65 % of antioxidant activity. Some of the extracts showed more than 60 % of inhibition of DPPH in the lowest concentration (0.01 mg/mL), including Amansia sp., Bostrychia tenella, Cryptonemia seminervis, Hypnea musciformis, Plocamium brasiliense (1), and S. clavata. Both Amansia sp., and C. seminervis presented the most relevant antioxidant potential, with percentage of inhibition greater than 70 % in the three tested concentrations. These two species were then analyzed by nuclear magnetic resonance spectroscopy (NMR) and were selected for guided fractionation bioassay. They both presented lipid compounds, fatty acids, esters of fatty acids, triglycerides, and sterols as major components. The fractionation of extracts revealed that the organic fractions were responsible for the antioxidant activity. The results obtained through this work indicate that the analyzed seaweeds are a promising source of compounds with high antioxidant potential.     

Vascular endothelial growth factor and related molecules in acute lung injury.

VEGFs and their receptors have been implicated in the regulation of vascular permeability in many organ systems, including the lung. Increased permeability and interstitial and pulmonary edema are prominent features of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Extrapolating data from other organ systems and animal experiments have suggested that overexpression of VEGF functions primarily as proinjurious molecules in the lung. Recent data, from animal models as well as from patients with ARDS, have shown decreased levels of VEGF in the lung. The role of VEGF and related molecules in ALI/ARDS is, therefore, controversial: what has become clear is that there are many unique features in the regulation of pulmonary vascular permeability and in VEGF expression in the lung. In this review, we explore a growing body of literature looking at the expression and function of VEGF and related molecules in different models of ALI and in patients with ALI/ARDS. Novel evidence points to a potential role of VEGF in promoting repair of the alveolar-capillary membrane during recovery from ALI/ARDS. Understanding the role of VEGF in this disease process is crucial for developing new therapeutic strategies for ALI/ARDS.     

Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples

In this study, we evaluated several techniques for the detection of the yeast form of Cryptococcus in decaying wood and measured the viability of these fungi in environmental samples stored in the laboratory. Samples were collected from a tree known to be positive for Cryptococcus and were each inoculated on 10 Niger seed agar (NSA) plates. The conventional technique (CT) yielded a greater number of positive samples and indicated a higher fungal density [in colony forming units per gram of wood (CFU.g^-1) ] compared to the humid swab technique (ST). However, the difference in positive and false negative results between the CT-ST was not significant. The threshold of detection for the CT was 0.05.10³ CFU.g^-1, while the threshold for the ST was greater than 0.1.10³ CFU^-1. No colonies were recovered using the dry swab technique. We also determined the viability of Cryptococcus in wood samples stored for 45 days at 25ºC using the CT and ST and found that samples not only continued to yield a positive response, but also exhibited an increase in CFU.g^-1, suggesting that Cryptococcus is able to grow in stored environmental samples. The ST.1, in which samples collected with swabs were immediately plated on NSA medium, was more efficient and less laborious than either the CT or ST and required approximately 10 min to perform; however, additional studies are needed to validate this technique.     

Transmission of <Emphasis Type="Italic">Methylobacterium mesophilicum</Emphasis> by <Emphasis Type="Italic">Bucephalogonia xanthophis</Emphasis> for paratransgenic control strategy of Citrus variegated chlorosis

Methylobacterium mesophilicum, originally isolated as an endophytic bacterium from citrus plants, was genetically transformed to express green fluorescent protein (GFP). The GFP-labeled strain of M. mesophilicum was inoculated into Catharanthus roseus (model plant) seedlings and further observed colonizing its xylem vessels. The transmission of this endophyte by Bucephalogonia xanthophis, one of the insect vectors that transmit Xylella fastidiosa subsp. pauca, was verified by insects feeding from fluids containing the GFP bacterium followed by transmission to plants and isolating the endophyte from C. roseus plants. Forty-five days after inoculation, the plants exhibited endophytic colonization by M. mesophilicum, confirming this bacterium as a nonpathogenic, xylem-associated endophyte. Our data demonstrate that M. mesophilicum not only occupy the same niche of X. fastidiosa subsp. pauca inside plants but also may be transmitted by B. xanthophis. The transmission, colonization, and genetic manipulation of M. mesophilicum is a prerequisite to examining the potential use of symbiotic control to interrupt the transmission of X. fastidiosa subsp. pauca, the bacterial pathogen causing Citrus variegated chlorosis by insect vectors.     

Floral resource partitioning by social wasps (Hymenoptera: Vespidae) and bees (Hymenoptera: Apoidea) in an area of caatinga in Brazil

Wasps and bees are important components of flower visitor guilds in the Neotropical region. The abundance of social wasps and bees, collected during flower visits, was used to calculate niche breadth and niche overlap indices, in order to characterize the utilization of the floral resources by those insects. Samples were taken monthly, for 13 months (156h), by two collectors which captured the specimens on flowers using entomological nets, while walking along a way in an area of caatinga at Itatim, State of Bahia, Brazil. Wasps and bees heavily visited a few sources of floral resources, but the most visited plants by each group were different, and few plant species were important for both groups, resulting in low niche overlap between bees and wasps. The niche overlap among wasp species was generally higher than among bee species. The general overlap, which takes into consideration all species together was low (< 30%).     

A practical approach to the choice of a suitable detergent and optimal conditions for solubilizing a membrane protein

The main objective of this laboratory practical class was to teach students how a detergent and the best experimental conditions are chosen to solubilize a given membrane protein. Kidney Na,K-ATPase was chosen as the protein of interest and anionic, neutral and zwitterionic detergents were tested. Simple laboratory experiments were designed to study the effect of the detergent on the activity of the enzyme, the effect of detergent concentration on solubilization, the effect of protein concentration on enzyme solubilization, and the effect of time and temperature of incubation during enzyme solubilization. This resulted in the selection of an appropriate detergent for the solubilization of the protein taking into account smaller inactivation factors, more effective solubilization (more effective solubilization with a better detergent-protein relationship), lower inactivation temperature and time of incubation of the membrane protein with the detergent. The results obtained showed that instantaneous incubation of Na,K-ATPase with C(12)E(8) (1:1 w/w) at 4 degrees C resulted in a more efficient solubilization and had a smaller denaturing effect on the solubilized enzyme.     

Expression of Parkin,APC, APE1, and Bcl-xL in Colorectal Polyps

Colorectal cancer can develop through molecular, chromosomal, and epigenetic cumulative changes that transform the normal intestinal epithelium into the colorectal polyps, called conventional adenomas (CAs) or serrated polyps (SPs), recognized as precursors of invasive colorectal neoplasia. These benign lesions need to explore the morphology, histological diagnosis, and biomarkers profile to accurately characterize lesions with potential for evolution to cancer. This study aimed to correlate the immunohistochemical expression of Parkin and Adenomatous Polyposis Coli (APC; tumor suppressors), Human Apurinic/Apyrimidinic endonuclease 1 (APE1), and B-cell lymphoma-extra-large (Bcl-xL; oncogenic proteins) in sporadic colorectal polyps with clinical, endoscopic, and diagnostic data. Immunohistochemical analysis was performed on tissue microarray samples of 306 polyps. Based on the Allred score, the expressions were graduated in the cytoplasm and nucleus of superficial and cryptic cells. There was higher Parkin nuclear expression (p=0.006 and 0.010) and APC cytoplasmic expression in cryptic cells (p<0.001) in SPs. CAs, APE1 (p<0.001) and Bcl-xL (p<0.001) were more expressed in the nuclei and cytoplasms, respectively. These results are related to the biological role proposed for these proteins in cellular functions. They can contribute to the diagnosis criteria for polyps and improve the knowledge of biomarkers that could predict cancer development:     

Genetic constraints for thermal coadaptation in <Emphasis Type="Italic">Drosophila subobscura</Emphasis>

Background  

Behaviour has been traditionally viewed as a driver of subsequent evolution because behavioural adjustments expose organisms to novel environments, which may result in a correlated evolution on other traits. In Drosophila subobscura, thermal preference and heat tolerance are linked to chromosomal inversion polymorphisms that show parallel latitudinal clines worldwide, such that "cold-climate" ("warm-climate") chromosome arrangements collectively favour a coherent response to colder (warmer) settings as flies carrying them prefer colder (warmer) conditions and have lower (higher) knock out temperatures. Yet, it is not clear whether a genetic correlation between thermal preference and heat tolerance can partially underlie such response.     

HMB supplementation: clinical and athletic performance-related effects and mechanisms of action

Amino acids such as leucine and its metabolite α-ketoisocaproate (KIC), are returning to be the focus of studies, mainly because of their anti-catabolic properties, through inhibition of muscle proteolysis and enhancement of protein synthesis. It is clear that these effects may counteract catabolic conditions, as well as enhance skeletal muscle mass and strength in athletes. Moreover, beta-hydroxy-beta-methylbutyrate (HMB) has been shown to produce an important effect in reducing muscle damage induced by mechanical stimuli of skeletal muscle. This review aims to describe the general scientific evidence of KIC and HMB supplementation clinical relevance, as well as their effects (e.g., increases in skeletal muscle mass and/or strength), associated with resistance training or other sports. Moreover, the possible mechanisms of cell signaling regulation leading to increases and/or sparing (during catabolic conditions) of skeletal muscle mass are discussed in detail based on the recent literature.     

Cold activity and tolerance of the entomopathogenic fungus Tolypocladium spp. to UV-B irradiation and heat

Studies on the stress resistance of insect-pathogenic fungi are very important to better understand the survival of these organisms in the environment. In this study, we examined the cold activity (8 ± 1 °C for 7 days), UV-B tolerance (Quaite-weighted UV-B irradiance at 847.90 mW m⁻² for 1, 2, 3, and 4 h), and wet-heat tolerance (45 °C for 1, 2, 3, and 4 h) of two isolates of Tolypocladiumcylindrosporum (ARSEF 3392 and 5558), one isolate of Tolypocladium geodes (ARSEF 3275), and two isolates of Tolypocladium inflatum (ARSEF 4772 and 4877) based on their germination, compared with Metarhizium robertsii (ARSEF 2575). After 3 h of UV-B exposure, T. cylindrosporum germinated at a greater rate than the other Tolypocladium species and had similar viability to that of the M. robertsii. Most Tolypocladium isolates, however, were less UV-B tolerant than M. robertsii. The T.cylindrosporum isolates were also the most thermotolerant, with similar tolerance to the M. robertsii. The isolates of T. inflatum and T. geodes, which had similar heat tolerance, were the least heat tolerant compared with the isolates of T. cylindrosporum and M. robertsii. After 4 h of heat exposure, the germination of T. inflatum and T. geodes isolates was not significantly different. For cold activity, both T.cylindrosporum isolates germinated to ca. 100% in only 3 days. Approximately 50% of the two T. inflatum isolates germinated, and less than 5% of T. geodes germinated after 3 days. All fungal isolates, however, completely germinated by the seventh day, except M.robertsii. The isolates of T. cylindrosporum, therefore, were the most heat and UV-B tolerant, and had the highest cold activity compared to the other species. The tolerance of M. robertsii to UV-B radiation and heat was similar to that of T.cylindrosporum.