Neochloris oleoabundans cell wall rupture through melittin peptide: a new approach to increase lipid recovery.

OBJECTIVES: Microalgae cell wall affects the recovery of lipids, representing one of the main difficulties in the development of biofuel production. This work aimed to test a new method based on melittin peptide to induce a cellular disruption in N. oleoabundans. RESULTS: Neochloris oleoabundans cells were grown at 32 °C in the presence of a high concentration of nitrate-phosphate, causing a cell disruption extent of 83.6%. Further, a two-fold increase in lipid recovery following melittin treatment and solvent extraction was observed. Additionally, it was possible to verify the effects of melittin, both before and after treatment on the morphology of the cells. Scanning electron microscopy (SEM) and confocal images of the melittin-treated microalgae revealed extensive cell damage with degradation of the cell wall and release of intracellular material. CONCLUSIONS: Melittin produced a selective cell wall rupture effect in N. oleoabundans under some culture conditions. These results represent the first report on the effect of melittin on lipid recovery from microalgae.

A new RP-HPLC method as an auxiliary tool for optimization of sample preparation procedures for tracing of PPCPs of different hydrophilicities.

Recently, pharmaceutical and personal care products (PPCPs) have received considerable attention because of their increasing use. Analysis of PPCPs presents a significant analytical challenge, with high-performance liquid chromatography (HPLC) in reversed-phase mode, as the most widely used analytical technique. To facilitate the optimization of the procedures that are applied in the early stages of sample preparation, a simple and fast HPLC method is proposed in this work for the separation of some PPCPs with a wide range of hydrophilicity. Two columns were evaluated (Atlantis dC18 and Discovery HS F5); as for mobile phases: a formate buffer (40 mmol L-1, pH 4) and methanol were tested in a gradient mode. The fluorinated column allowed better separation in a shorter time and better resolution for all analytes (Rs > 1). The proposed method delivered good performance for the tracing of PPCPs and is a suitable alternative to traditional C18-based HPLC methods.

Arachidonyl-2'-chloroethylamide (ACEA), a synthetic agonist of cannabinoid receptor, increases CB1R gene expression and reduces dyskinesias in a rat model of Parkinson's disease.

l-Dopa is the most effective drug used for Parkinson's disease (PD), but after long-term treatment, the vast majority of PD patients develop abnormal involuntary movements (AIMs) termed l-Dopa-induced dyskinesia (LID). Cannabinoid receptors in the basal ganglia can modulate motor functions, but their role in the treatment of LID is controversial. Therefore, the aim of this study is to evaluate the motor behavior and mRNA expression of the cannabinoid receptor-1 (CB1R), encoded by the Cnr1 gene, in the striatum and globus pallidus of a 6-hydroxydopamine rat model of PD. The evaluated rats had 6-hydroxydopamine-induced injury, LID, and LID treated with arachidonyl-2'-chloroethylamide (ACEA), a cannabinoid receptor agonist. Contralateral turns and AIMs were recorded to assess motor behavior. Gene expression was quantified by reverse transcription coupled with quantitative polymerase chain reaction using TaqMan probes. Behavioral evaluations demonstrated that dyskinetic rats treated with ACEA had a significant reduction in AIMs compared to the dyskinetic group. The expression of CB1R mRNA was significantly decreased in the 6-hydroxydopamine-injured and dyskinetic rats, compared to intact rats. The striata of dyskinetic rats treated with ACEA exhibited highly significant increases in CB1R mRNA expression. Contrary to results in the striatum, a lower CB1R expression was observed in globus pallidus from dyskinetic ACEA-treated group. In summary, significant differences in mRNA expression of CB1R were found between the evaluated groups of rats, suggesting the occurrence of compensatory mechanisms that may result in the ACEA-mediated reduction of dyskinesias in a rat model of PD.

Avenanthramide-C prevents amyloid formation of bovine serum albumin.

The misfolding of protein and its assembly into amyloid fibrils with a characteristic ß-sheet-rich secondary structure, cause a lot of illnesses. Polyphenols have been extensively studied as a class of amyloid inhibitors, whose effect depends on the position and number of hydroxyl groups around the flavone backbone. In this study, we used bovine serum albumin (BSA) as an amyloid model to test the anti-amyloid effects of Avenanthramide-C (Avn-C), a molecule with a long aliphatic linker between two aromatic rings. We used spectroscopy techniques like thioflavin T fluorescence and circular dichroism, to follow the ß-sheet-rich aggregates of BSA upon incubation at 68 °C. Our results demonstrated that Avn-C shows higher inhibitory effect on BSA oligomerization at micromolar concentrations, than Epigallocatechin gallate (EGCG) and Curcumin, proving for the first time, that Avn-C can serve as potential molecule in preventing protein aggregation.

In Vitro Effect of Methanolic Extract of Argemone mexicana against Trichomonas vaginalis.

Infections caused by Trichomonas vaginalis in humans are one of the main public health problems caused by sexually transmitted diseases. Objective of this study was to evaluate potential biological activity of the medicinal plant Argemone mexicana (Mexican poppy) on T. vaginalis. Methanolic extracts of the stems and leaves of A. mexicana, and different fractions were prepared with solvents of different polarities. The extracts and functional groups were detected containing sterols, triterpenes, quinones, flavonoids and, alkaloids. Extracts from both the stems and leaves of A. mexicana inhibited the growth of T. vaginalis with half-maximal inhibitory concentration value of 70.6 and 67.2 µg/ml, respectively. In the active fractions, the most abundant compounds were berberine and jatrorrhizine, with presumed antiparasitic activity.

Preparation of polymer nanoparticles loaded with Syzygium aromaticum essential oil: an oral potential application / Preparación de nanoparticulas polimericas cargadas con aceite esencial de Syzygium aromaticum: una potencial aplicación oral

Due to the biological activities of Syzygium aromaticum essential oil, its incorporation in methacrylate polymeric (Eudragit E100) nanoparticles (NP), physical characterization, and antimicrobial essays were evaluated. The clove bears great potential for applications in dentistry. The oil was obtained by hydrodistillation and oil loaded NP using the nanoprecipitation method. Particle size and polydispersity index were determined by photon correlation spectroscopy, and physical morphology by electron microscopy. Loading capacity and in vitro eugenol release were evaluated by gas mass chromatography, and the antimicrobial activity of oil loaded-NP was calculated against Streptococcus mutans. Different chemical ingredients were characterized, and eugenol was the principal compound with 51.55%. Polymer content was directly related to NP homogenous size, which was around 150 nm with spherical morphology. A 73.2% loading capacity of eugenol was obtained. Oil loaded NP presented a fickian-type release mechanism of eugenol. Antimicrobial activity to 300 µg/mL was obtained after 24 h.

Debido a las actividades biológicas del aceite esencial de Syzygium aromaticum, se evaluó su incorporación en nanopartículas (NP) de metacrilato polimérico (Eudragit E100), su caracterización y ensayos antimicrobianos. El clavo tiene un gran potencial para aplicaciones en odontología. El aceite se obtuvo por hidrodestilación y las NP cargado de aceite utilizando el método de nanoprecipitación. El tamaño de partícula y el índice de polidispersidad se determinaron mediante espectroscopia de correlación fotónica y su morfología por microscopía electrónica. La capacidad de carga y la liberación de eugenol in vitro se evaluaron mediante cromatografía de gases en masa, y la actividad antimicrobiana se evaluó contra Streptococcus mutans. Se caracterizaron diferentes ingredientes químicos, siendo el eugenol el principal compuesto con 51.55%. El contenido de polímero se relacionó directamente con el tamaño homogéneo de NP, que fue de alrededor de 150 nm con morfología esférica. Se obtuvo un 73,2% de capacidad de carga de eugenol. El aceite cargado en NP presentó un mecanismo de liberación de eugenol de tipo fickiano. La actividad antimicrobiana a 300 µg/mL se obtuvo después de 24 h.

Differential interaction of α-synuclein N-terminal segment with mitochondrial model membranes.

Alpha-synuclein (α-syn) is an intrinsically-disordered protein that has been associated with Parkinson's disease through its deposition in an amyloid fibril form within Lewy Body. Several lines of evidence suggest that the physical association of α-syn with the mitochondrial membranes may cause membrane damage and mitochondrial dysfunction, playing an important role in disease progression. Although there is strong evidence that the N-terminus part of α-syn is essential for membrane affinity, cooperative formation of helical domains and regulation of mitochondria membrane permeability, the amino acids involve in this membrane binding is still controversial. Fluorescence spectroscopy, circular dichroism and Langmuir monolayer technique were used to elucidate this recognition process of mitochondrial membrane system by synthetic peptides derived from α-syn N-terminal segment. The results obtained in this work show that the first 15 amino acid of the α-syn N-terminal segment mainly participate in the anchoring, perturbing the membrane hydrophobic region, while the peptide corresponding to 16-30 residues interacts only with the phospholipid polar headgroup, confirming that the binding affinity of the N-terminus is nonuniform.

Biodegradable nanoparticles loaded with tetrameric melittin: preparation and membrane disruption evaluation.

Melittin is the main component of bee venom consisting of 26 amino acids that has multiple effects, including antibacterial, antiviral and anti-inflammatory in various cell types. This peptide forms pores in biological membranes and triggers cell death. Therefore it has potential as an anti-cancer therapy. However, the therapeutic application of melittin is limited due to its main side effect, hemolysis, which is especially pronounced following intravenous administration. In the present study, we formulated tetrameric melittin-carrying poly-D,L-lactic-co-glycolic acid nanoparticles (PLGA-NPs) and analyzed the lytic activity of this system on liposomes that resembles breast cancer cells. Tetrameric melittin binds avidly to PLGA-NPs with an encapsulation efficiency of 97% and retains its lytic activity demonstrating the effectiveness of PLGA-NPs as nanocarriers for this cytolytic peptide.

[Bone morphogenetic proteins (BMP): clinical application for reconstruction of bone defects]. / Proteínas morfogenéticas óseas (BMP): aplicación clínica para reconstrucción de defectos en hueso.

Since the introduction of bone morphogenetic proteins, their use has become an invaluable ally for the treatment of bone defects. These proteins are potent growth factors, related to angiogenic and osteogenic activity. The osteoinductive capacity of recombinant bone morphogenetic protein (rhBMP) in the formation of bone and cartilage has been confirmed in in vitro studies and evaluated in clinical trials. To obtain a therapeutic effect, administration is systemic, by injection over the physiological dose. Among the disadvantages, ectopic bone formation or high morbidity in cases of spinal fusion is observed. In this review, the roles of bone morphogenetic proteins in bone repair and clinical applications are analyzed. These findings represent advances in the study of bone regeneration and application of growth factors for more predictable results.

The Interaction of Alpha-synuclein with Membranes and its Implication in Parkinson's Disease: A Literature Review.

Alpha-synuclein belongs to the class of intrinsically disordered proteins lacking a well-folded structure under physiological conditions. The conversion of alpha-synuclein from a soluble monomer to an insoluble fibril may underlie the neurodegeneration associated with Parkinson's disease (PD). Although the exact mechanism of alpha-synuclein toxicity is still unknown, it has been proposed that alpha-synuclein disturbs membrane structure, leading to increased membrane permeability and eventual cell death. This review highlights the significant role played by fluorescence techniques in unraveling the nature of interactions between alpha-synuclein and membranes and its implications in PD.

Análisis funcional de oligómeros de alfa-sinucleína en la permeabilidad de membranas / Functional analysis of oligomeric alpha-synuclein in membrane permeabilization / Análise funcional dos oligômeros de alfa-sinucleína na permeabilidade das membranas

La enfermedad de Parkinson es un desorden neurodegenerativo común originado por la muerte celular dentro de la substancia nigra pars compacta. Se caracteriza por la presencia de agregados intracelulares proteicos compuestos principalmente por la alfa-sinucleína. Aunque los mecanismos moleculares por los cuales esta proteína contribuye a la toxicidad neuronal todavía se desconocen, se ha sugerido que los intermediarios oligoméricos son citotóxicos y permeabilizan las membranas celulares posiblemente a través de complejos que forman un poro en la bicapa; sin embargo, este mecanismo es altamente controversial. Así pues es necesario identificar el mecanismo por el cual ocurre la permeabilización de membranas para entender la interacción entre oligómeros y lípidos y poder estimar la relevancia biológica de este proceso.En este trabajo se evaluó por espectroscopía de fluorescencia la liberación de contenidos acuosos originados por oligómeros de alfa-sinucleína desde vesículas fosfolipídicas de distinta composición mediante el método ANTS/DPX. Los resultados muestran que la disrupción de membranas solo ocurre en presencia de lípidos aniónicos y también por parámetros de empaquetamiento lipídico, lo que sugiere que la accesibilidad a la región hidrofóbica de las vesículas modula la interacción lípido-oligómero.

Parkinson's disease is a common neurodegenerative disorder marked by increased cell death within the substantia nigra pars compacta. It is characterized by the presence of intracellular aggregates composed primarily of the protein alpha-synuclein. How the aggregation of a-synuclein is related to neuronal degeneration is an important unresolved question. Oligomeric intermediates have been found to be more toxic to cells than monomeric or fibrillar forms of the protein. A possible mechanism by which oligomers could be toxic is through the disruption and permeabilization of cellular membranes. The proposed disruption mechanism is the formation of pore-like structures within the lipid bilayer although this mechanism is still highly controversial. To identify the mechanism through which membrane permeabilization is facilitated and to estimate the biological relevance of this process, it is crucial to have a greater knowledge of the lipid-oligomer interaction. The membrane disruptive effect of Alpha-synuclein oligomers on lipid vesicles of different headgroup composition using the ANTS/DPX assay was evaluated in this work. It was shown that membrane permeabilization is mainly determined by the presence of negatively charged lipids and also by lipid packing parameters, suggesting that the accessibility to the bilayer hydrocarbon core modulates oligomer-membrane interaction.

pars compacta. é caracterizada pela presença de agregados intracelulares protéicos compostos especialmente pela alfa-sinucleína.Mesmo que se desconheça os mecanismos moleculares por onde essa proteína contribui para toxicidade neuronal, existe uma possibilidade de que os intermediários oligoméricos sejam citotóxicos, e permeabilizam as membranas celulares possivelmente através de complexos que formam um poro na capa dupla, entretanto, este mecanismo gera muita controvérsia. Sendo assim, é necessário identificar o mecanismo responsável pela permeabilidade das membranas para entender a interação entre os oligômeros e os lipídios, e para ter uma estimativa da relevância biológica deste processo. Neste trabalho, analisamos através de espectroscopia de fluorescência, a liberação dos conteúdos aquoso originados por oligômeros de alfa-sinucleína a partir das vesículas fosfolídicas de composição diferente através do método ANTS/DPX. Os resultados mostraram que a ruptura de membranas ocorrerá somente diante da presença de lipídios aniônicos, e também pelos parâmetros de empacotamento lipídico, e isso sugere que a acessibilidade à região hidrofóbica das vesículas faz a modulação da interação lípidio-oligômero.

Análisis funcional de oligómeros de alfa-sinucleína en la permeabilidad de membranas / Functional analysis of oligomeric alpha-synuclein in membrane permeabilization / Análise funcional dos olig¶meros de alfa-sinucleína na permeabilidade das membranas

La enfermedad de Parkinson es un desorden neurodegenerativo común originado por la muerte celular dentro de la substancia nigra pars compacta. Se caracteriza por la presencia de agregados intracelulares proteicos compuestos principalmente por la alfa-sinucleína. Aunque los mecanismos moleculares por los cuales esta proteína contribuye a la toxicidad neuronal todavía se desconocen, se ha sugerido que los intermediarios oligoméricos son citotóxicos y permeabilizan las membranas celulares posiblemente a través de complejos que forman un poro en la bicapa; sin embargo, este mecanismo es altamente controversial. Así pues es necesario identificar el mecanismo por el cual ocurre la permeabilización de membranas para entender la interacción entre oligómeros y lípidos y poder estimar la relevancia biológica de este proceso. En este trabajo se evaluó por espectroscopía de fluorescencia la liberación de contenidos acuosos originados por oligómeros de alfa-sinucleína desde vesículas fosfolipídicas de distinta composición mediante el método ANTS/ DPX. Los resultados muestran que la disrupción de membranas solo ocurre en presencia de lípidos aniónicos y también por parámetros de empaquetamiento lipídico, lo que sugiere que la accesibilidad a la región hidrofóbica de las vesículas modula la interacción lípido-oligómero.(AU)

Parkinsons disease is a common neurodegenerative disorder marked by increased cell death within the substantia nigra pars compacta. It is characterized by the presence of intracellular aggregates composed primarily of the protein alpha-synuclein. How the aggregation of a-synuclein is related to neuronal degeneration is an important unresolved question. Oligomeric intermediates have been found to be more toxic to cells than monomeric or fibrillar forms of the protein. A possible mechanism by which oligomers could be toxic is through the disruption and permeabilization of cellular membranes. The proposed disruption mechanism is the formation of pore-like structures within the lipid bilayer although this mechanism is still highly controversial. To identify the mechanism through which membrane permeabilization is facilitated and to estimate the biological relevance of this process, it is crucial to have a greater knowledge of the lipid-oligomer interaction. The membrane disruptive effect of Alpha-synuclein oligomers on lipid vesicles of different headgroup composition using the ANTS/DPX assay was evaluated in this work. It was shown that membrane permeabilization is mainly determined by the presence of negatively charged lipids and also by lipid packing parameters, suggesting that the accessibility to the bilayer hydrocarbon core modulates oligomer-membrane interaction.(AU)

A doenþa de Parkinson é uma condiþÒo neuro-degenerativa comum que se origina na morte celular dentro da substÔncia nigra pars compacta. é caracterizada pela presenþa de agregados intracelulares protéicos compostos especialmente pela alfa-sinucleína.Mesmo que se desconheþa os mecanismos moleculares por onde essa proteína contribui para toxicidade neuronal, existe uma possibilidade de que os intermediários oligoméricos sejam citotóxicos, e permeabilizam as membranas celulares possivelmente através de complexos que formam um poro na capa dupla, entretanto, este mecanismo gera muita controvérsia. Sendo assim, é necessário identificar o mecanismo responsável pela permeabilidade das membranas para entender a interaþÒo entre os olig¶meros e os lipídios, e para ter uma estimativa da relevÔncia biológica deste processo. Neste trabalho, analisamos através de espectroscopia de fluorescÛncia, a liberaþÒo dos conteúdos aquoso originados por olig¶meros de alfa-sinucleína a partir das vesículas fosfolídicas de composiþÒo diferente através do método ANTS/DPX. Os resultados mostraram que a ruptura de membranas ocorrerá somente diante da presenþa de lipídios ani¶nicos, e também pelos parÔmetros de empacotamento lipídico, e isso sugere que a acessibilidade O regiÒo hidrofóbica das vesículas faz a modulaþÒo da interaþÒo lípidio-olig¶mero.(AU)

Acemannan, an extracted polysaccharide from Aloe vera: A literature review.

In this review, the composition, actions, and clinical applications of acemannan in medicine and its effectiveness as an adjunct in the treatment of diseases are presented. An electronic literature search was performed up to January 2014 for studies and research presenting data to validate the efficacy of acemannan. A total of 50 titles, abstracts and full-text studies were selected and reviewed. Acemannan has various medicinal properties like osteogenic, anti-inflammatory, and antibacterial, which accelerate healing of lesions. Also, acemannan is known to have antiviral and antitumor activities in vivo through activation of immune responses. It was concluded that Aloe vera has immense potential as a therapeutic agent. Even though the plant is a promising herb with various clinical applications in medicine and dentistry, more clinical research needs to be undertaken to validate and explain the action of acemannan in healing, so that it can be established in the field of medicine and a more precise understanding of the biological activities of these is required to develop Aloe vera as a pharmaceutical source.

Interfacial behavior of recombinant forms of human pulmonary surfactant protein SP-C.

The behavior at air-liquid interfaces of two recombinant versions of human surfactant protein SP-C has been characterized in comparison with that of native palmitoylated SP-C purified from porcine lungs. Both native and recombinant proteins promoted interfacial adsorption of dipalmitoylphosphatidylcholine bilayers to a limited extent, but catalyzed very rapid formation of films from different lipid mixtures containing both zwitterionic and anionic phospholipids. Once at the interface, the recombinant variants exhibited compression-driven structural transitions, consistent with changes in the orientation of the deacylated N-terminal segment, which were not observed in the native protein. Compression isotherms of lipid/protein films suggest that the recombinant SP-C forms promote expulsion at high pressures of a higher number of lipid molecules per mole of protein than does native SP-C. A more dynamic conformation of the N-terminal segment in recombinant SP-C forms is likely also responsible for facilitating compression-driven condensation of domains in anionic phospholipid films as observed by epifluorescence microscopy. Finally, both native palmitoylated SP-C and the phenylalanine-containing recombinant versions facilitate similarly the repetitive compression-expansion dynamics of lipid/protein films, which were able to reach maximal surface pressures with practically no hysteresis along multiple quasi-static or dynamic cycles.

Synthetic peptides representing the N-terminal segment of surfactant protein C modulate LPS-stimulated TNF-alpha production by macrophages.

Surfactant protein C (SP-C) consists of a hydrophobic alpha-helix inserted in pulmonary surfactant membranes, and a more polar N-terminal palmitoylated segment exposed to the aqueous phase. Previously, we showed that SP-C inserted in lipid vesicles interacts with bacterial lipopolysaccharide (LPS) and reduces LPS-elicited responses. As the N-terminal segment of SP-C was the most likely region responsible for these effects, a set of synthetic analogs of this stretch (SPC((1-13)) ) were studied. Binding studies showed that SPC((1-13)) binds LPS to the same extent as porcine SP-C under lipid-free conditions. In the absence of serum, both, palmitoylated and non-palmitoylated analogs enhanced the binding of tritiated LPS to macrophages as well as the LPS-induced production of TNF-alpha by these cells. These effects were reversed in the presence of serum; the analogs reduced the production of TNF-alpha in LPS-stimulated macrophages, probably by interfering with the formation of LPS/CD14/LBP complexes as suggested by analysis of the fluorescence emitted by a FITC derivative of Re-LPS. Our data indicate that water-soluble analogs of the N-terminal segment of SP-C can reduce LPS effects in the presence of serum, and thus might help in the design of new derivatives to fight endotoxic shock and pro-inflammatory events.

Effects of palmitoylation on dynamics and phospholipid-bilayer-perturbing properties of the N-terminal segment of pulmonary surfactant protein SP-C as shown by 2H-NMR.

It has been proposed that palmitoylation of the N-terminal segment of surfactant protein SP-C is important for maintaining association of pulmonary surfactant complexes with interfacial films compressed to high pressures at the end of expiration. In this study, we examined surfactant membrane models containing palmitoylated and nonpalmitoylated synthetic peptides, based on the N-terminal SP-C sequence, in dipalmitoylphosphatidylcholine (DPPC)/egg phosphatidylglycerol (7:3, w/w) by (2)H-NMR. Perturbations of lipid properties by the peptide versions were compared in samples containing chain- and headgroup-deuterated lipid (DPPC-d(62) and DPPC-d(4) respectively). Also, deuterated peptide palmitate chains were compared with those of DPPC in otherwise identical lipid-protein mixtures. Palmitoylated peptide increased average DPPC-d(62) chain orientational order slightly, particularly for temperatures spanning gel and liquid crystalline coexistence, implying penetration of palmitoylated peptide into ordered membrane. In contrast, the nonpalmitoylated peptide had a small disordering effect in this temperature range. Both peptide versions perturbed DPPC-d(4) headgroup orientation similarly, suggesting little effect of palmitoylation on the largely electrostatic peptide-headgroup interaction. Deuterated acyl chains attached to the SP-C N-terminal segment displayed a qualitatively different distribution of chain order, and lower average order, than DPPC-d(62) in the same membranes. This likely reflects local perturbation of lipid headgroup spacing by the peptide portion interacting with the bilayer near the peptide palmitate chains. This study suggests that SP-C-attached acyl chains could be important for coupling of lipid and protein motions in surfactant bilayers and monolayers, especially in the context of ordered phospholipid structures such as those potentially formed during exhalation, when stabilization of the respiratory surface by surfactant is the most crucial.