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BACKGROUND: Humic acids (HAs) are macromolecules classified within the group of humic substances that are mainly related to the agricultural and environmental sectors, but they have attracted interest from the medicine, pharmaceutical and cosmetic industries. However, these latter sectors depend on developing extraction and purification technologies for adequate use. Thus, this paper aims to study the partitioning and recovery of HA using alkaline two‐phase aqueous systems (ATPSs) based on alkali metal‐based hydroxides and alcohols. Initially, the influence of alcohols (methanol, ethanol, 1‐propanol, and 2‐propanol) and hydroxides [sodium (NaOH), potassium (KOH) and lithium (LiOH)] in the phase diagrams construction was addressed. RESULTS: The phase formation is correlated to an increase in the hydrophobicity of alcohols and hydroxides, which allows for the enlargement of the biphasic region. In the proposed systems, HA is always partitioned to the hydroxide‐rich phase. Increasing the hydrophobicity of the alcohol favors the migration of HA to the opposite phase, while increasing the hydrophilicity of the hydroxides leads to better partition and recovery values. It was observed that increasing TLL favors the recovery of HA. Furthermore, there was a decrease in alcohol concentration in the hydroxide‐rich phase with an increase in the alkyl chain and TLL, improving the recovery. Finally, the best reached‐recovery value was 98.18 ± 0.41% (KHA = 0.038 ± 0.02) for ATPS formed by 1‐propanol + NaOH with TLL ≈ 55 at 298 K. CONCLUSIONS: Alkaline systems can be a novel route for recovering humic substances from the environment. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The global population of Dicotyles tajacu (Linnaeus, 1758) (Cetartiodactyla: Tayassuidae), commonly known as the collared peccary and distributed in the Neotropics, is currently in decline due to anthropogenic pressures. In this study, five microsatellite loci were used to genetically characterize a group of 20 captive‐born collared peccaries intended for reintroduction. This study aimed to evaluate the genetic diversity and relatedness of captive individuals using microsatellite markers. The genetic data generated were used to evaluate the viability of the reintroduction and to propose measures for the management and conservation of this species. In this study, we found relatively high genetic diversity indices, indicating that the group was genetically diverse. Inbreeding coefficients with negative values were observed, indicating an excess of alleles in heterozygosis and an absence of inbreeding. One locus showed deviation from Hardy–Weinberg equilibrium, which may have been caused by the mixing of individuals from different origins. Relatedness analysis indicated that some individuals were highly related, with coefficients indicating they may be first‐degree relatives. Our findings indicate that the studied group has enough genetic diversity to be released into nature, but the high individual relatedness found would require the adoption of strategies after the release of animals in the wild to ensure their persistence. Highlights: The captive group of collared peccaries showed relatively high genetic diversity indices, indicating that the group was genetically diverse.Inbreeding coefficients with negative values were observed, indicating an excess of alleles in heterozygosis and an absence of inbreeding.Our findings indicate that the studied group has enough genetic diversity to be released into nature. [ABSTRACT FROM AUTHOR]

New Findings: What is the central question of this study?Is the cardiovascular phenotype of high blood pressure observed in rats salt loaded with 2% NaCl in drinking solution a blood volume‐dependent hypertension?What is the main finding and its importance?Animals exposed to 2% NaCl drinking solution develop hypertension, with dominance of sympathetic outflow and high [Na+] in the cerebrospinal fluid, but without changes in the blood volume. The phenotype of salt‐dependent hypertension might be related to accumulation of [Na+] in the cerebrospinal fluid, which makes it an interesting animal model in which to study the neuronal pathways involved in control of the circulation in osmotic challenge conditions. Evidence suggests that hypertension induced by high salt intake is correlated with an autonomic imbalance that favours sympathetic hyperactivity and an increase in vascular resistance, indicating a neurogenic component to this pathology. Although there are several animal models in which to study salt‐induced hypertension with prolonged exposure to a high‐sodium diet, here we sought to investigate whether the increase in arterial blood pressure of rats subjected to a short exposure to high salt, with 2% NaCl drinking solution instead of water, relies on changes in the circulating blood volume. Male Wistar rats were divided randomly into three groups: euhydrated (EU, n = 10), salt loaded (SL, n = 13) and water deprived (WD, n = 6). The SL rats exhibited a significant increase in mean arterial blood pressure, with a large low‐frequency component of systolic arterial blood pressure variability, when compared with the EU group. Circulating blood volume did not differ between SL and EU rats, but it was lower in WD rats. Compared with EU rats, the [Na+] in cerebrospinal fluid was higher in SL rats and similar in magnitude to the WD rats. Plasma [Na+] did not differ between SL and EU rats, but it was higher in WD rats. Collectively, our data suggest that the hypertension induced by a short exposure to high salt intake closely resembles a neurogenic mechanism, but not a blood volume‐dependent mechanism, with cumulative [Na+] in the cerebrospinal fluid that could be associated with changes in the neurochemistry of autonomic nuclei, which are highly susceptible to osmotic stress related to high salt consumption. [ABSTRACT FROM AUTHOR]

New Findings: What is the central question of this study?How does swimming exercise training impact hydro‐electrolytic balance, renal function, sympathetic contribution to resting blood pressure and cerebrospinal fluid (CSF) [Na+] in rats fed a high‐sodium diet from weaning?What is the main finding and its importance?An exercise‐dependent reduction in blood pressure was associated with decreased CSF [Na+], sympathetically driven vasomotor tonus and renal fibrosis indicating that the anti‐hypertensive effects of swimming training in rats fed a high‐sodium diet might involve neurogenic mechanisms regulated by sodium levels in the CSF rather than changes in blood volume. High sodium intake is an important factor associated with hypertension. High‐sodium intake with exercise training can modify homeostatic hydro‐electrolytic balance, but the effects of this association are mostly unknown. In this study, we sought to investigate the effects of swimming training (ST) on cerebrospinal fluid (CSF) Na+ concentration, sympathetic drive, blood pressure (BP) and renal function of rats fed a 0.9% Na+ (equivalent to 2% NaCl) diet with free access to water for 22 weeks after weaning. Male Wistar rats were assigned to two cohorts: (1) fed standard diet (SD) and (2) fed high‐sodium (HS) diet. Each cohort was further divided into trained and sedentary groups. ST normalised BP levels of HS rats as well as the higher sympathetically related pressor activity assessed by pharmacological blockade of ganglionic transmission (hexamethonium). ST preserved the renal function and attenuated the glomerular shrinkage elicited by HS. No change in blood volume was found among the groups. CSF [Na+] levels were higher in sedentary HS rats but were reduced by ST. Our findings showed that ST effectively normalised BP of HS rats, independent of its effects on hydro‐electrolytic balance, which might involve neurogenic mechanisms regulated by Na+ levels in the CSF as well as renal protection. [ABSTRACT FROM AUTHOR]

Cruzain is an established target for the identification of novel trypanocidal agents, but how good are in vitro/in vivo correlations? This work describes the development of a random forests model for the prediction of the bioavailability of cruzain inhibitors that are Trypanosoma cruzi killers. Some common properties that characterize drug‐likeness are poorly represented in many established cruzain inhibitors. This correlates with the evidence that many high‐affinity cruzain inhibitors are not trypanocidal agents against T. cruzi. On the other hand, T. cruzi killers that present typical drug‐like characteristics are likely to show better trypanocidal action than those without such features. The random forests model was not outperformed by other machine learning methods (such as artificial neural networks and support vector machines), and it was validated with the synthesis of two new trypanocidal agents. Specifically, we report a new lead compound, Neq0565, which was tested on T. cruzi Tulahuen (β‐galactosidase) with a pEC50 of 4.9. It is inactive in the host cell line showing a selectivity index (SI = EC50cyto/EC50T. cruzi) higher than 50. [ABSTRACT FROM AUTHOR]

BACKGROUND: Rosemary leaves have been widely employed in the food and pharmaceutical industry due to the presence of important compounds. However, during the extraction process, in addition to the target biomolecules [chlorophyll (Chl), and rosmarinic acid], other components (phenolic compounds) are also extracted. This work focuses on the development of a sequential and selective protocol for the extraction and concentration of Chl using an aqueous micellar two‐phase system, and extraction and purification of rosmarinic acid using an aqueous two‐phase system (ATPS). RESULTS: Firstly, the extraction and purification of Chls were studied. The Chls rich‐extract obtained using the best conditions of aqueous solution of Triton X‐100 (5 wt%) and phosphate buffer (50 mmol L−1), 50 °C solid–liquid ratio was evaluated at 1:100 and 60 min (Chl a = 69.3 ± 1.9 mg 100 g−1; Chl b = 41.1 ± 1.2 mg 100 g−1 and total Chl = 110.5 ± 3.1 mg 100 g−1) were submitted to temperature above cloud point. The Chl b and total Chl were concentrated 3.1 and 1.7 times. Further, the extraction and purification of rosmarinic acid were investigated. Ethanol, methanol, and acetonitrile (80 wt%) at 50°C were investigated; and after extraction, the rosmarinic acid rich‐extract were add in the ATPS composed of organic solvent + tripotassium phosphate (K3PO4). The extraction efficiencies were observed in the top phase (100%) for all systems. The highest purification factor was found using the ATPS based on acetonitrile (50 wt%) + K3PO4 (20 wt%). CONCLUSIONS: The sequential protocols to extract Chls and purify rosmarinic acid can be applied. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The emergence of antibiotic resistance drives an essential race against time to reveal new molecular structures capable of addressing this alarming global health problem. Snake venoms are natural catalogs of multifunctional toxins and privileged frameworks, which serve as potential templates for the inspiration of novel treatment strategies for combating antibiotic resistant bacteria. Phospholipases A2 (PLA2s) are one of the main classes of antibacterial biomolecules, with recognized therapeutic value, found in these valuable secretions. Recently, a number of biomimetic oligopeptides based on small fragments of primary structure from PLA2 toxins has emerged as a meaningful opportunity to overcome multidrug‐resistant clinical isolates. Thus, this review will highlight the biochemical and structural properties of antibacterial PLA2s and peptides thereof, as well as their possible molecular mechanisms of action and key roles in development of effective therapeutic strategies. Chemical strategies possibly useful to convert antibacterial peptides from PLA2s to efficient drugs will be equally addressed. [ABSTRACT FROM AUTHOR]

New Findings What is the central question of this study? In this study, we sought to investigate whether cardiovascular responses to peripheral chemoreflex activation of rats recovered from protein restriction are related to activation of AT1 receptors., What is the main finding and its importance? This study highlights the fact that angiotensinergic mechanisms activated by AT1 receptors do not support increased responses to peripheral chemoreflex activation by KCN in rats recovered from protein restriction. Also, we found that protein restriction led to increased resting ventilation in adult rats, even after recovery., The effects of a low-protein diet followed by recovery on cardiorespiratory responses to peripheral chemoreflex activation were tested before and after systemic angiotensin II type 1 (AT1) receptor antagonism. Male Fischer rats were divided into control and recovered (R-PR) groups after weaning. The R-PR rats were fed a low-protein (8%) diet for 35 days and recovered with a normal protein (20%) diet for 70 days. Control rats received a normal protein diet for 105 days (CG105). After cannulation surgery, mean arterial pressure, heart rate, respiratory frequency, tidal volume and minute ventilation were acquired using a digital recording system in freely moving rats. The role of angintensin II was evaluated by systemic antagonism of AT1 receptors with losartan (20 mg kg−1 i.v.). The peripheral chemoreflex was elicited by increasing doses of KCN (20-160 μg kg min−1, i.v.). At baseline, R-PR rats presented increased heart rate and minute ventilation (372 ± 34 beats min−1 and 1.274 ± 377 ml kg−1 min−1) compared with CG105 animals (332 ± 22 beats min−1 and 856 ± 112 ml kg−1 min−1). Mean arterial pressure was not different between the groups. Pressor and bradycardic responses evoked by KCN (60 μg kg−1) were increased in R-PR (+45 ± 13 mmHg and −77 ± 47 beats min−1) compared with CG105 rats (+25 ± 17 mmHg and −27 ± 28 beats min−1), but no difference was found in the tachypnoeic response. These differences were preserved after losartan. The data suggest that angiotensin II acting on AT1 receptors may not be associated with the increased heart rate, increased minute ventilation and acute cardiovascular responses to peripheral chemoreflex activation in rats that underwent postweaning protein restriction followed by recovery. [ABSTRACT FROM AUTHOR]

Different isoforms of ataxin-2 are predicted in Drosophila and may underlie different cellular processes. Here, we validated the isoforms B and C of Drosophila ataxin-2 locus ( dAtx2), which we found to be expressed in various tissues and at different levels during development. dAtx2-B m RNA was detected at low amounts during all developmental stages, whereas dAtx2-C m RNA levels increase by eightfold from L3 to pupal-adult stages. Higher amounts of dAtx2-B protein were detected in embryos, while dAtx2-C protein was also expressed in higher levels in pupal-adult stages, indicating post-transcriptional control for isoform B and transcription induction for isoform C, respectively. Moreover, in the fat body of L3 larvae dAtx2-C, but not dAtx2-B, accumulates in cytoplasmic foci that colocalize with sec23, a marker of endoplasmic reticulum exit sites ( ERES). Interestingly, animals subjected to selective knockdown of dAtx2 in the larval fat body do not complete metamorphosis and die at the third larval stage or early puparium. Additionally, larvae knocked down for dAtx2, grown at 29 °C, are significantly smaller than control animals due to reduction in DNA replication and cell growth, which are consistent with the decreased levels of phosphorylated- AKT observed in the fat body. Based on the localization of ataxin-2 (dAtx2-C) in ERESs, and on the phenotypes observed by dAtx2 knockdown in the larval fat body, we speculate a possible role for this protein in processes that regulate ERES formation. These data provide new insights into the biological function of ataxin-2 with potential relevance to neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Tyrosine sulfation is a common post-translational modification operative in many biological processes, including hemostasis and intracellular trafficking. However, the precise structural and functional role of sulfotyrosine residues is not fully understood, so there is a demand for further detailed studies on the role of tyrosine sulfation in biochemical processes. Unfortunately, studies on the biological roles of tyrosine sulfation are hampered by difficulties in gaining access to large quantities of high-purity and homogeneous sulfoproteins and sulfopeptides. This, however, may be addressed by appropriate solid-phase peptide synthesis strategies, and these constitute the core subject of this review. An overview of efficient approaches to the synthesis of sulfopeptides and their associated pros and cons is presented. [ABSTRACT FROM AUTHOR]

Propolis is a beehive product with a very complex chemical composition, used since ancient times in several therapeutic treatments. As a contribution to the improvement of drugs against several tropical diseases caused by protozoa, we screened Portuguese propolis and its potential floral sources Populus x Canadensis and Cistus ladanifer against Plasmodium falciparum, Leishmania infantum, Trypanosoma brucei and Trypanosoma cruzi. The toxicity against MRC-5 fibroblast cells was evaluated to assess selectivity. The in vitro assays were performed following the recommendations of WHO Special Programme for Research and Training in Tropical Diseases (TDR) and revealed moderate activity, with the propolis extracts presenting the relatively highest inhibitory effect against T. brucei. Additionally, the antimicrobial activity against Staphylococcus aureus, Candida albicans, Trichophyton rubrum and Aspergillus fumigatus was also verified with the better results observed against T. rubrum. The quality of the extracts was controlled by evaluating the phenolic content and antioxidant activity. The observed biological activity variations are associated with the variable chemical composition of the propolis and the potential floral sources under study. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction Propolis is a chemically complex resinous substance collected by honeybees ( Apis mellifera) from tree buds, comprising plant exudates, secreted substances from bee metabolism, pollen and waxes. Its chemical composition depends strongly on the plant sources available around the beehive, which have a direct impact in the quality and bioactivity of the propolis. Being as Portugal is a country of botanical diversity, the phenolic characterisation of propolis from the different regions is a priority. Objective Extensive characterisation of the phenolic composition of Portuguese propolis from different continental regions and islands. Method Forty propolis ethanolic extracts were analysed extensively by liquid chromatography with diode-array detection coupled to electrospray ionisation tandem mass spectrometry (LC-DAD-ESI-MS n). Results Seventy-six polyphenols were detected in the samples and two groups of propolis were established: the common temperate propolis, which contained the typical poplar phenolic compounds such as flavonoids and their methylated/esterified forms, phenylpropanoid acids and their esters, and an uncommon propolis type with an unusual composition in quercetin and kaempferol glycosides - some of them never described in propolis. Conclusion The method allowed the establishment of the phenolic profile of Portuguese propolis from different geographical locations, and the possibility to use some phenolic compounds, such as kaempferol-dimethylether, as geographical markers. Data suggest that other botanical species in addition to poplar trees can be important sources of resins for Portuguese propolis. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The synthesis of three new quinoxaline mono- N-oxides derivatives, namely, 2- tert-butoxycarbonyl-3-methylquinoxaline- N-oxide, 2-phenylcarbamoyl-3-ethylquinoxaline- N-oxide, and 2-carbamoyl-3-methylquinoxaline- N-oxide, from their corresponding 1,4-di- N-oxides is reported. Samples of these compounds were used for a thermochemical study, which allowed derivation of their gaseous standard molar enthalpies of formation [ABSTRACT FROM AUTHOR]

The present work reports the first experimental thermochemical study of mono-N-oxides derived from quinoxaline, namely, 3-methoxycarbonyl-2-methyl-quinoxaline N-oxide and 3-ethoxycarbonyl-2-methyl-quinoxaline N-oxide. The values of the enthalpies of formation, in the condensed state, and of the enthalpies of sublimation, derived from static bomb calorimetry and Calvet microcalorimetry measurements, respectively, are combined to derive the standard molar enthalpies of formation in the gaseous phase for these two compounds. From the latter values, the first and second N&bond;O bond dissociation enthalpies for the corresponding di-N-oxides have been obtained. The gas-phase experimental results are also compared with calculated data obtained with a density functional theory approach. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background Cell penetrating peptides have been successfully used to mediate the intracellular delivery of a wide variety of molecules of pharmacological interest. The main aim of the present work was to evaluate the potential of the S413-PV cell penetrating peptide to mediate the intracellular delivery of plasmid DNA, aiming at its use in gene therapy applications. The S413-PV cell penetrating peptide is a chimeric peptide that results from the combination of a cell penetrating sequence derived from the Dermaseptin S4 peptide with the nuclear localization signal present in the Simian Virus 40 (SV40) large T antigen. Methods S413-PV cell penetrating peptide and cationic liposomes composed of 1,2-dioleoyl-3-trimethylammonium-propane:1,2-dioleoyl- sn-glycero-3-phosphoethanolamine were complexed with pDNA at different charge ratios. Complexation of pDNA was assessed by gel electrophoresis. Luciferase assay, fluorescence microscopy and fluorescence-activated cell sorting analysis were used to evaluate reporter gene delivery to TSA and HeLa cells. Cytotoxicity of the pDNA complexes was assessed by Alamar blue assay. Results Complexes obtained through electrostatic association of the S413-PV cell penetrating peptide with plasmid DNA are able to very efficiently mediate transfection, particularly at high peptide/DNA charge ratios. Additionally, our results clearly demonstrate that, both in HeLa and TSA cells, ternary complexes, resulting from association of cationic liposomes to peptide/DNA complexes, are significantly more efficient in mediating transfection than the corresponding peptide/DNA or cationic liposome/DNA complexes. Conclusions Overall, our data highlight the potential of cell penetrating peptides for the development of improved nonviral gene delivery systems. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article details a study which evaluated the new methodology based on Perfumery Ternary Diagram® (PTD®) that is used to predict the odor value (OV) of a perfume mixture. Using a perfume test mixture of limonene, geraniol, vanillin and ethanol, the authors validated the methodology through experimental measurements of odor threshold values and headspace concentrations. They examined the influence of the odor threshold values on the PTD® and compared the experimental OV values with OV values predicted by the PTD® model.

The gaseous standard molar enthalpies of formation of two 2-R-3-methylquinoxaline-1,4-dioxides (R = benzoyl or tert-butoxycarbonyl), at T = 298.15 K, were derived using the values for the enthalpies of formation of the compounds in the condensed phase, measured by static bomb combustion calorimetry, and for the enthalpies of sublimation, measured by Knudsen effusion, using a quartz crystal oscillator. The three dimensional structure of 2-tert-butoxycarbonyl-3-methylquinoxaline-1,4-dioxide has been obtained by X-ray crystallography showing that the two N&bond;O bond lengths in this compound are identical. The experimentally determined geometry in the crystal is similar to that obtained in the gas-phase after computations performed at the B3LYP/6-311 + G(2d,2p) level of theory. The experimental and computational results reported allow to extend the discussion about the influence of the molecular structure on the dissociation enthalpy of the N&bond;O bonds for quinoxaline 1,4-dioxide derivatives. As found previously, similar N&bond;O bond lengths in quinoxaline-1,4-dioxide compounds are not linked with N&bond;O bonds having the same strength. Copyright © 2007 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A new concept of perfumery ternary diagrams (PTDs), based on an analogy between perfume pyramid structure and engineering ternary diagrams, is described. These diagrams allow a fast theoretical evaluation of the odor value in the headspace for all possible concentrations of a perfume liquid mixture constituted by three fragrant components and one solvent base, thus eliminating a long trial-and-error experimental work to analyze the headspace composition. The effect of the nonidealities in the liquid phase arising from molecular interactions was analyzed, as well as the effect of ethanol in a test mixture composed of limonene, geraniol, and vanillin. A diffusion model was used to simulate the evaporation of a small and finite sample of perfume test mixture. The changes in the liquid phase and in the gas-liquid interface were followed using the PTDs developed in this work. A characteristic point of a PTD was used as the initial mixture for simulating the evaporation of the small amount of perfume as a function of time and space. The performance parameters, such as impact, tenacity, diffusion, and volume, were discussed based on these results. [ABSTRACT FROM AUTHOR]

A new concept of perfumery ternary diagrams (PTDs), based on an analogy between perfume pyramid structure and engineering ternary diagrams, was developed in this work. These diagrams allow a fast evaluation of the odour value in the headspace for all possible combinations of a perfume liquid mixture with three fragrant components and one solvent. A theoretical prediction of the PTD was made, based on perfumery binary lines (PBLs) and perfumery ternary points (PTPs). As an example, this methodology was applied to the system: benzaldehyde-2-phenylethanol-eugenol in ethanol. The effect of ethanol content in the ternary system was also studied. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]