Natural Benzo/Acetophenones as Leads for New Synthetic Acetophenone Hybrids Containing a 1,2,3-Triazole Ring as Potential Antifouling Agents

Marine biofouling is a natural process that represents major economic, environmental, and health concerns. Some booster biocides have been used in biofouling control, however, they were found to accumulate in environmental compartments, showing negative effects on marine organisms. Therefore, it is urgent to develop new eco-friendly alternatives. Phenyl ketones, such as benzophenones and acetophenones, have been described as modulators of several biological activities, including antifouling activity (AF). In this work, acetophenones were combined with other chemical substrates through a 1,2,3-triazole ring, a strategy commonly used in Medicinal Chemistry. In our approach, a library of 14 new acetophenone–triazole hybrids was obtained through the copper(I)-catalyzed alkyne-azide cycloaddition “click” reaction. All of the synthesized compounds were evaluated against the settlement of a representative macrofouling species, Mytilus galloprovincialis, as well as on biofilm-forming marine microorganisms, including bacteria and fungi. The growth of the microalgae Navicula sp. was also evaluated after exposure to the most promising compounds. While compounds 6a, 7a, and 9a caused significant inhibition of the settlement of mussel larvae, compounds 3b, 4b, and 7b were able to inhibit Roseobacter litoralis bacterial biofilm growth. Interestingly, acetophenone 7a displayed activity against both mussel larvae and the microalgae Navicula sp., suggesting a complementary action of this compound against macro- and microfouling species. The most potent compounds (6a, 7a, and 9a) also showed to be less toxic to the non-target species Artemia salina than the biocide Econea^®. Regarding both AF potency and ecotoxicity activity evaluation, acetophenones 7a and 9a were put forward in this work as promising eco-friendly AF agents.     

Effect of silicon fertilization on the tolerance of Castanea sativa Mill. seedlings against Cryphonectria parasitica Barr.

Journal of Plant Diseases and Protection - Chestnut is an important crop in Portugal, representing an important source of revenue for mountain regions in this country. However, it has been strongly...     

Glutamate receptor-like genes form Ca2+ channels in pollen tubes and are regulated by pistil D-serine

Elevations in cytosolic free calcium concentration ([Ca(2+)](cyt)) constitute a fundamental signal transduction mechanism in eukaryotic cells, but the molecular identity of Ca(2+) channels initiating this signal in plants is still under debate. Here, we show by pharmacology and loss-of-function mutants that in tobacco and Arabidopsis, glutamate receptor-like channels (GLRs) facilitate Ca(2+) influx across the plasma membrane, modulate apical [Ca(2+)](cyt) gradient, and consequently affect pollen tube growth and morphogenesis. Additionally, wild-type pollen tubes grown in pistils of knock-out mutants for serine-racemase (SR1) displayed growth defects consistent with a decrease in GLR activity. Our findings reveal a novel plant signaling mechanism between male gametophyte and pistil tissue similar to amino acid-mediated communication commonly observed in animal nervous systems.     

Lipid class composition of the microalga Pavlova lutheri: eicosapentaenoic and docosahexaenoic acids

The lipid classes of Pavlova lutheri, cultivated in semicontinuous mode, were studied by thin-layer chromatography and gas chromatography in attempts to describe the distribution of fatty acid residues within its lipid pool, with special emphasis on eicosapentaenoic (C20:5n-3, EPA) and docosahexaenoic (C22:6n-3, DHA) acids. Neutral lipids and glycolipids were the major constituents and accounted for approximately 57 and 24% of the total fatty acid residues (TFA), respectively. Phospholipids accounted for approximately 10% of TFA. Two lipid classes, acylated steryl glycosides (SG) and diphosphatidylglycerols (DPG), were eventually identified in P. lutheri for the first time. The nonpolar fraction was mainly composed of triacylglycerol (TAG), whereas the polar fraction was mainly composed of monogalactosylacylglycerols (MGDG). The distribution of total EPA and DHA within the lipid pool was calculated in attempts to ascertain the quality of said microalgae as a feed source, as well as the possibility of enhancement of individual fatty acid production and extraction thereafter. EPA was especially concentrated in MGDG (approximately 45%) and TAG (approximately 33%); conversely, DHA was dispersed through various classes, especially within TAG (approximately 27%), DPG (approximately 22%), and betaine lipids (21%).     

Genetic diversity of papaya (Carica papaya L.) F5 recombinant inbred lines using the Ward-MLM strategy

Genetic Resources and Crop Evolution - The development of segregating populations in papaya allows the development of new high fruit yield and excellent fruit quality pure line or hybrid cultivars....     

Microalgae as sources of carotenoids

Marine microalgae constitute a natural source of a variety of drugs for pharmaceutical, food and cosmetic applications-which encompass carotenoids, among others. A growing body of experimental evidence has confirmed that these compounds can play important roles in prevention (and even treatment) of human diseases and health conditions, e.g., cancer, cardiovascular problems, atherosclerosis, rheumatoid arthritis, muscular dystrophy, cataracts and some neurological disorders. The underlying features that may account for such favorable biological activities are their intrinsic antioxidant, anti-inflammatory and antitumoral features. In this invited review, the most important issues regarding synthesis of carotenoids by microalgae are described and discussed-from both physiological and processing points of view. Current gaps of knowledge, as well as technological opportunities in the near future relating to this growing field of interest, are also put forward in a critical manner.     

Biocompatibility of the Biopolymer Cyanoflan for Applications in Skin Wound Healing

There is a great demand for the development of novel wound dressings to overcome the time and costs of wound care performed by a vast number of clinicians, especially in the current overburdened healthcare systems. In this study, Cyanoflan, a biopolymer secreted by a marine unicellular cyanobacterium, was evaluated as a potential biomaterial for wound healing. Cyanoflan effects on cell viability, apoptosis, and migration were assessed in vitro, while the effect on tissue regeneration and biosafety was evaluated in healthy Wistar rats. The cell viability and apoptosis of fibroblasts and endothelial cells was not influenced by the treatment with different concentrations of Cyanoflan, as observed by flow cytometry. Moreover, the presence of Cyanoflan did not affect cell motility and migratory capacity, nor did it induce reactive oxygen species production, even revealing an antioxidant behavior regarding the endothelial cells. Furthermore, the skin wound healing in vivo assay demonstrated that Cyanoflan perfectly adapted to the wound bed without inducing systemic or local oxidative or inflammatory reaction. Altogether, these results suggest that Cyanoflan is a promising biopolymer for the development of innovative applications to overcome the many challenges that still exist in skin wound healing.     

Endocrine (plasma cortisol and glucose) and behavioral (locomotor and self-feeding activity) circadian rhythms in Senegalese sole (Solea senegalensis Kaup 1858) exposed to light/dark cycles or constant light

The existence of daily rhythms under light/dark (LD) cycles in plasma cortisol, blood glucose and locomotor and self-feeding activities, as well as their persistence (circadian nature) under constant light (LL), was investigated in Senegalese sole (Solea senegalensis). For the cortisol and glucose rhythms study, 48 soles were equally distributed in 8 tanks and exposed to a 12:12 LD cycle and natural water temperature (experiment 1). After an acclimation period, blood was sampled every 3 h until a 24-h cycle was completed. Blood glucose levels were measured immediately after sampling, while plasma cortisol was measured later by ELISA. In experiment 2, the fish were exposed to LL for 11 days, and after this period, the same sampling procedure was repeated. For the study of locomotor and self-feeding rhythms (experiment 3), two groups of sole were used: one exposed to LD and the other to LL. Each group was distributed within 3 tanks equipped with infrared photocells for the record of locomotor activity, and self-feeders for feeding behavior characterization. The results revealed a marked oscillation in cortisol concentrations during the daily cycle under LD, with a peak (35.65 ± 3.14 ng/ml) in the afternoon (15:00 h) and very low levels during the night (5.30 ± 1.09 ng/ml). This cortisol rhythm persisted under LL conditions, with lower values (mean cortisol concentration = 7.12 ± 1.11 ng/ml) and with the peak shifted by 3 h. Both rhythms were confirmed by COSINOR analysis (p < 0.05). The synchronizing role of temperature and feeding schedule, in addition to light, is also discussed. Diel rhythms of glucose were not evident in LD or LL. As to locomotor and self-feeding activity, a very marked rhythm was observed under LD, with higher activity observed during the night, with acrophases located at 2:14 and 3:37 h, respectively. The statistical significance of daily rhythms was confirmed by COSINOR analysis. Under LL, both feeding and locomotor rhythms persisted, with an endogenous period (τ) around 22.5 h. In short, our findings described for the first time the existence of circadian cortisol and behavioral circadian rhythms in flat fish. Such results revealed the importance of taking into account the time of day when assessing stress responses and evaluating physiological indicators of stress in fish.     

Antioxidant activity of a catechol derived from abietic acid

The demand for novel effective antioxidant-based drugs has led to the synthesis and evaluation of the antioxidant potential in several molecules derived from natural compounds. In this work the in vitro antioxidant activity of an abietic acid-derived catechol (methyl 11,12-dihydroxyabietate-8,11,13-trien-18-oate, MDTO) was evaluated. This substance, possessing important biological properties, is similar to carnosic acid, a natural antioxidant from rosemary or sage leaves. Aiming to understand the antioxidant activity of MDTO, the energetics of its O-H bond, using time-resolved photoacoustic calorimetry (TR-PAC), was investigated. On energetic grounds it is predicted that MDTO is a good free radical scavenger, although its activity is lower than that of quercetin, a very effective antioxidant, which was used for comparison. In agreement with these predictions, the DPPH(*) and ABTS(*+) radical scavenging activities are lower than those of quercetin. In addition, MDTO also reacts with HOCl, a powerful proinflammatory oxidant produced by activated neutrophils, and protects liposomes against iron-ascorbate-induced oxidation. The discussion of these results foresees potential applications of MDTO as an antioxidant.