Activity of resveratrol triesters against primary acute lymphoblastic leukemia cells

Resveratrol is a common polyphenol of plant origin known for its cancer prevention and other properties. Its wider application is limited due to poor water solubility, low stability, and weak bioavailability. To overcome these limitations, a series of 13 novel resveratrol triesters were synthesized previously. In this paper, we describe the synthesis of 3 additional derivatives and the activity of all 16 against primary acute lymphoblastic leukemia cells. Of these, 3 compounds were more potent than resveratrol (IC₅₀ = 10.5 µM) namely: resveratryl triacetate (IC₅₀ = 3.4 µM), resveratryl triisobutyrate (IC₅₀ = 5.1 µM), and resveratryl triisovalerate (IC₅₀ = 4.9 µM); all other derivatives had IC₅₀ values of >10 µM. Further studies indicated that the active compounds caused G1 phase arrest, increased expression of p53, and induced characteristics of apoptotic cell death. Moreover, the compounds were only effective in cycling cells, with cells arrested in G1 phase being refractory.     

Testing the optimal defense hypothesis in Stryphnodendron adstringens (Fabaceae,Mimosoideae) leaves: the role of structure,number, position and nectar composition of extrafloral nectaries

Stryphnodendron adstringens is a common Cerrado tree that possesses extrafloral nectaries (EFNs) on its leaves, which are located at the base and apex of the rachis and along the secondary veins. The position of EFNs and their nectar production can be affected by defense strategies because plant organs possess different values and herbivory vulnerability. Here we aimed to elucidate anatomy, histochemistry, nectar composition and EFN number on leaves of S. adstringens in the light of the optimal defense hypothesis. We found a convergence on anatomy and histochemical characterization because the three studied types of EFNs have epidermis, secretory parenchyma and vascular tissue, showing phenolic compounds and polysaccharides in the secretory parenchyma cells. The nectar contained glucose, fructose and sucrose, which attract ants of the Camponotus and Cephalotes genus. We found differences in the number of EFNs along the secondary veins and in the nectar composition between EFNs located at the base and apex of the rachis of the leaf. The number of EFNs on the secondary veins increases from the base to the apex, suggesting a strategy to induce ant patrolling over the entire leaf region. EFNs at the base secreted more nectar, which should be related to the protection of the leaf base, which is the part most vulnerable to herbivore attack and the most valued organ. We concluded that EFNs of S. adstringens are anti‐herbivore defenses whose pattern matches the predictions of the optimal defense hypothesis.     

Decomposition and nitrogen dynamics of turtle grass (<Emphasis Type="Italic">Thalassia testudinum</Emphasis>) in a subtropical estuarine system

Seagrass beds are pivotal in the functioning of coastal ecosystems in terms of productivity, organic matter turnover and nutrient cycling. Aiming to document decay and nitrogen (N) dynamics of turtle grass (Thalassia testudinum) in a subtropical estuarine system, decomposition patterns of leaves and rhizomes were characterized and compared. Nitrogen usage during decomposition of tissues, and of live tissues and epiphytes growing on live leaves, was also quantified and compared. Stable isotope ratios allowed tracing N within the seagrass bed, following N incorporation into seagrass tissues from the surrounding media (water, sediment). Leaves had a higher N content and decomposed at a faster rate (~6.4 times) compared to rhizomes. Leaching of soluble materials explain the rapid (0–3 days) initial mass loss of leaves (20%) and rhizomes (18%); with a loss of 85 and 56%, respectively, by the end of the study (77 days). Overall, leaves released N while rhizomes immobilized it. Nitrogen concentration was significantly different among live tissues. The main source of N for both seagrass tissues was the sediment, and water column for epiphytes. Differences in decomposition rates among seagrass tissues can be explained by the quality of the substrate and its susceptibility to microbial use. Seagrass leaves and rhizomes are equally important in taking up nutrients from either the water column or the sediments. This study provides a platform to study energy and matter transfers through detrital foodwebs linked to seagrass meadows.     

Raman spectroscopy and PCA‐SVM as a non‐invasive diagnostic tool to identify and classify qualitatively glycated hemoglobin levels in vivo

In this study we identify and classify high and low levels of glycated hemoglobin (HbA1c) in healthy volunteers (HV) and diabetic patients (DP). Overall, 86 subjects were evaluated. The Raman spectrum was measured in three anatomical regions of the body: index fingertip, right ear lobe, and forehead. The measurements were performed to compare the difference between the HV and DP (22 well controlled diabetic patients (WCDP) (HbA1c <6.5%), and 49 not controlled diabetic patients (NCDP) (HbA1c ≥6.5%)). Multivariable methods such as principal components analysis (PCA) combined with support vector machine (SVM) were used to develop effective diagnostic algorithms for classification among these groups. The forehead of HV versus WCDP showed the highest sensitivity (100%) and specificity (100%). Sensitivity (100%) and specificity (60%), were highest in the forehead of WCDP, versus NCDP. In HV versus NCDP, the fingertip had the highest sensitivity (100%) and specificity (80%). The efficacy of the diagnostic algorithm by receiver operating characteristic (ROC) curve was confirmed. Overall, our study demonstrated that the

combination of Raman spectroscopy and PCA‐SVM are feasible non‐invasive diagnostic tool in diabetes to classify qualitatively high and low levels of HbA1c in vivo.     

Expansion strategies for human mesenchymal stromal cells culture under xeno‐free conditions

Choosing the culture system and culture medium used to produce cells are key steps toward a safe, scalable, and cost‐effective expansion bioprocess for cell therapy purposes. The use of AB human serum (AB HS) as an alternative xeno‐free supplement for mesenchymal stromal cells (MSC) cultivation has increasingly gained relevance due to safety and efficiency aspects. Here we have evaluated different scalable culture systems to produce a meaningful number of umbilical cord matrix‐derived MSC (UCM MSC) using AB HS for culture medium supplementation during expansion and cryopreservation to enable a xeno‐free bioprocess. UCM MSC were cultured in a scalable planar (compact 10‐layer flasks and roller bottles) and 3‐D microcarrier‐based culture systems (spinner flasks and stirred tank bioreactor). Ten layer flasks and roller bottles enabled the production of 2.6 ± 0.6 × 10⁴ and 1.4 ± 0.3 × 10⁴ cells/cm². UCM MSC‐based microcarrier expansion in the stirred conditions has enabled the production of higher cell densities (5.5–23.0 × 10⁴ cells/cm²) when compared to planar systems. Nevertheless, due to the moderate harvesting efficiency attained, (80% for spinner flasks and 46.6% for bioreactor) the total cell number recovered was lower than expected. Cells maintained the functional properties after expansion in all the culture systems evaluated. The cryopreservation of cells (using AB HS) was also successfully carried out. Establishing scalable xeno‐free expansion processes represents an important step toward a GMP compliant large‐scale production platform for MSC‐based clinical applications. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1358–1367, 2017     

Non-dermatophytic moulds: onychomycosis in four patients infected with the human immunodeficiency virus

Patients infected with human immunodeficiency virus (HIV) are a risk group for onychomycosis, fungal infections caused mainly by dermatophytes and yeast. However, non-dermatohytic moulds are becoming common agents for nail infections in this population of patients. We report four cases of onychomycosis caused by non-dermatophytic moulds (Aspergillus niger, Scytalidium hyalinum, Scytalidium dimidiatum and Fusarium solani) in patients infected with HIV from Recife, Pernambuco, Brazil. Onychomicosis by non-dermatophytic species in HIV-positive patients requires special attention in the clinical and the laboratory. A proper diagnosis is necessary to establish the specific and adequate treatment, preventing fungal invasion.     

Heparin effect on in vitro nuclear maturation of bovine oocytes

Oocytes undergo numerous biochemical and morphological changes during their development from preantral to preovulatory phases. In vitro studies have suggested several compounds that might induce oocyte maturation. Heparin is a natural component of ooplasm, follicular fluid and uterine fluid and previous studies indicated that it might act as a chromatin maturation factor in bovine oocytes. We tested this hypothesis in vitro by timing germinal vesicle breakdown (GVBD) and first polar body (PB) formation without any other natural or introduced factors that might influence the rate of oocyte maturation. We also determined if these oocytes could be fertilized. Bovine oocytes were incubated in a salt medium and TCM 199 supplemented with different concentrations of heparin for 24 h at 37.5 degrees C in a humidified atmosphere of 5% CO2. With 1.0 and 6.5 mg/ml heparin, the time of GVBD was reduced from 4.7+/-1.1 h to about 1.5 h and the time of first PB formation was reduced from 22.0+/-1.1 h to 9.0-11.0 h in salt medium. In TCM 199, only 6.5 mg/ml heparin significantly reduced the time of PB formation. In both incubation media, 1.0 and 6.5 mg/ml heparin induced GVBD, extrusion of the first PB and formation of the metaphase II nucleus. Moreover, heparin did not interfere with the fertilization of oocytes matured in TCM 199. Based on the results, we propose that heparin plays an important role in the rearrangement of the oocyte chromatin and acts as an oocyte maturation factor.     

Owls and rabbits: predation against substandard individuals of an easy prey

The interactions among the multiple factors regulating predator-prey relationships make predation a more complex process than previously thought. The degree to which substandard individuals are captured disproportionately seems to be better a function of the difficulty of prey capture than of the hunting techniques (coursing vs. ambushing predators). That is, when the capture and killing of a prey species is easy, substandard individuals will be predated in proportion to their occurrence in the prey population. In the present study, we made use of eagle owls Bubo bubo and their main prey, the rabbit Oryctolagus cuniculus : (a) the brightness of the white tails of rabbits seems to be correlated with the physical condition of individuals, (b) by using the tails of predated rabbits as an index of individual condition, we found that eagle owls seem to prefer substandard individuals (characterized by duller tails), and (c) by using information from continuous radiotracking of 14 individuals, we suggest that the difficulty of rabbit capture could be low. Although the relative benefits of preying on substandard individuals should considerably decrease when a predator is attacking an easy prey, we hypothesise that the eagle owl preference for substandard individuals could be due to the easy detection of poor individuals by a visual cue, the brightness of the rabbit tail. Several elements allow us to believe that this form of visual communication between a prey and one of its main predators could be more widespread than previously thought. In fact: (a) visual signalling plays a relevant role in intraspecific communication in eagle owls and, consequently, visual signals could also play a role in interspecific interactions, and (b) empirical studies showed that signals may inform the predator that it has been perceived, or that the prey is in a sufficiently healthy state to elude the predator.