Assessment of Antimicrobial and Cytotoxic Activities of Liposomes Loaded with Curcumin and Lippia origanoides Essential Oil.

(1) Introduction: Curcumin and Lippia origanoides essential oils have a broad spectrum of biological activities; however, their physicochemical instability, low solubility, and high volatility limit their therapeutic use. Encapsulation in liposomes has been reported as a feasible approach to increase the physicochemical stability of active substances, protect them from interactions with the environment, modulate their release, reduce their volatility, improve their bioactivity, and reduce their toxicity. To date, there are no reports on the co-encapsulation of curcumin and Lippia origanoides essential oils in liposomes. Therefore, the objective of this work is to prepare and physiochemical characterize liposomes loaded with the mixture of these compounds and to evaluate different in vitro biological activities. (2) Methods: Liposomes were produced using the thin-layer method and physiochemical characteristics were calculated. The antimicrobial and cytotoxic activities of both encapsulated and non-encapsulated compounds were evaluated. (3) Results: Empty and loaded nanometric-sized liposomes were obtained that are monodisperse and have a negative zeta potential. They inhibited the growth of Staphylococcus aureus and did not exhibit cytotoxic activity against mammalian cells. (4) Conclusions: Encapsulation in liposomes was demonstrated to be a promising strategy for natural compounds possessing antimicrobial activity.

Spiractinospora alimapuensis gen. nov., sp. nov., isolated from marine sediment of Valparaíso Bay (Chile) and proposal for reclassification of two species of the genus Nocardiopsis.

An alkaliphilic actinobacterium, designated VN6-2T, was isolated from marine sediment collected from Valparaíso Bay, Chile. Strain VN6-2T formed yellowish-white branched substrate mycelium without fragmentation. Aerial mycelium was well developed, forming wavy or spiral spore chains. Strain VN6-2T exhibited a 16S rRNA gene sequence similarity of 93.9 % to Salinactinospora qingdaonensis CXB832T, 93.7 % to Murinocardiopsis flavida 14-Be-013T, and 93.7 % to Lipingzhangella halophila 14-Be-013T. Genome sequencing revealed a genome size of 5.9 Mb and an in silico G+C content of 69.3 mol%. Both of the phylogenetic analyses based on 16S rRNA gene sequences and the up-to-date bacterial core gene sequences revealed that strain VN6-2T formed a distinct monophyletic clade within the family Nocardiopsaceae. Chemotaxonomic assessment of strain VN6-2T showed that the major fatty acids were iso-C16 : 0, anteiso-C17 : 0 and 10-methyl-C18 : 0, and the predominant respiratory quinones were MK-9, MK-9(H2) and MK-9(H4). Whole-cell hydrolysates contained meso-diaminopimelic acid as the cell-wall diamino acid, and ribose and xylose as the diagnostic sugars. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, aminophospholipids, glycolipid and phospholipid. Based on the results of this polyphasic study, a novel genus, Spiractinospora gen. nov., is proposed within the family Nocardiopsaceae and the type species Spiractinospora alimapuensis gen. nov., sp. nov. The type strain is VN6-2T (CECT 30026T, CCUG 66258T). On the basis of the phylogenetic results herein, we also propose that Nocardiopsis arvandica and Nocardiopsis litoralis are later heterotypic synonyms of Nocardiopsis sinuspersici and Nocardiopsis kunsanensis, respectively, for which emended descriptions are given.

Salivary markers of oxidative stress and periodontal pathogens in patients with periodontitis from Santander, Colombia / Marcadores salivales de estrés oxidativo y agentes patógenos periodontales en pacientes con periodontitis en Santander, Colombia

Introduction: Periodontitis affects more than 20% of the Latin American population. Oxidative markers are associated with greater progression of periodontitis; therefore, its role in pathogenesis should be studied. Objective: To determine the prevalence of the main oral bacteria and viruses associated with periodontitis and estimate the total antioxidant capacity and lipid peroxidation in saliva from patients with periodontitis. Materials and methods: We conducted systemically a cross-sectional study in 101 healthy subjects, 87 of whom had been diagnosed with periodontitis (P), according to the criteria of the Centers of Disease Control and Prevention and the American Academy of Periodontology, and 14 without periodontal pockets as controls (C). In subgingival samples, major viruses and dental pathogenic bacteria were identified using PCR techniques. The levels of total antioxidant capacity and malon-di-aldehyde (MDA) were determined by spectrophotometry in samples of unstimulated saliva. Results: The mean of periodontal depth pocket and clinical attachment loss in patients with periodontitis was 5.6 ± 1.7 and 6.1 ± 3.1 mm, respectively. The most prevalent microorganisms were Aggregatibacter actinomycetemcomitans (32.5%) and Porphyromonas gingivalis (18.6%). The patients from rural areas showed a higher percentage of A . actinomycetemcomitans (urban: 17.9% vs. rural: 48.9%, p=0.0018). In patients with periodontitis, the frequency of EBV, HSV1 & 2, and HCMV genes was 2.3%. Periodontitis patients had higher levels of MDA (P: 2.1 ± 1.5; C: 0.46 ± 0.3 µmol/g protein; p=0.0001) and total antioxidant capacity (P: 0.32 ± 0.2; C: 0.15 ± 0.1 mM; p< 0.0036). Oxidative markers showed no modifications due to the presence of periodontopathic bacteria. Conclusions: Aggregatibacter actinomycetemcomitans was the most prevalent bacteria; its presence did not modify the levels of oxidative markers in the saliva of patients with periodontitis.

Introducción. La periodontitis afecta a más del 20 % de la población latinoamericana. La presencia de marcadores de estrés oxidativo se asocia con una mayor progresión de periodontitis, por lo que su rol en la patogenia debe estudiarse. Objetivo. Determinar la prevalencia de las principales bacterias y virus asociados con la periodontitis y estimar la capacidad antioxidante total y la peroxidación de lípidos en la saliva de los pacientes con periodontitis. Materiales y métodos. Se hizo un estudio transversal en 87 sujetos sanos diagnosticados con periodontitis (P) según los criterios de los Centers of Disease Control and Prevention y la American Academy of Periodontology y 14 sujetos sin enfermedad periodontal como grupo control (C). En las muestras subgingivales se identificaron los principales virus y bacterias mediante técnicas de PCR. Los niveles de capacidad antioxidante total y malon-di-aldehído (MDA) se establecieron mediante espectrofotometría en muestras de saliva no estimulada. Resultados. Las medias de profundidad del sondaje y del nivel de inserción clínico periodontal en pacientes con periodontitis fueron 5,6 ± 1,7 y 6,1 ± 3,1 mm, respectivamente. Los microorganismos más prevalentes fueron Aggregatibacter actinomycetemcomitans (32,5 %) y Porphyromonas gingivalis (18,6 %). Los pacientes de áreas rurales registraron un mayor porcentaje de A. actinomycetemcomitans (urbano: 17,9 % Vs. rural: 48,9 %; p=0,0018). La frecuencia de los genes EBV, HSV1 y 2, y HCMV fue de 2,3 %. En pacientes con periodontitis se evidenciaron mayores niveles de MDA (P: 2,1 ± 1,5; C: 0,46 ± 0,3 µmol/g proteína; p=0,0001) y capacidad antioxidante total (P: 0,32 ± 0,2; C: 0,15 ± 0,1 mM; p<0,0036). La presencia de bacterias periodontales patógenas no modificó los marcadores oxidativos. Conclusiones.Aggregatibacter actinomycetemcomitans fue el agente patógeno mas prevalente. Su presencia no modificó los niveles de marcadores oxidativos en la saliva de los pacientes con periodontitis.

A Perspective on Thiazolidinone Scaffold Development as a New Therapeutic Strategy for Toxoplasmosis.

Toxoplasma gondii is one of the most successful parasites due to its ability to infect a wide variety of warm-blooded animals. It is estimated that one-third of the world's population is latently infected. The generic therapy for toxoplasmosis has been a combination of antifolates such as pyrimethamine or trimethoprim with either sulfadiazine or antibiotics such as clindamycin with a combination with leucovorin to prevent hematologic toxicity. This therapy shows limitations such as drug intolerance, low bioavailability or drug resistance by the parasite. There is a need for the development of new molecules with the capacity to block any stage of the parasite's life cycle in humans or in a different type of hosts. Heterocyclic compounds are promissory drugs due to its reported biological activity; for this reason, thiazolidinone and its derivatives are presented as a new alternative not only for its inhibitory activity against the parasite but also for its high selectivity-level with high therapeutic index. Thiazolidinones are an important scaffold known to be associated with anticancer, antibacterial, antifungal, antiviral, antioxidant, and antidiabetic activities. The molecule possesses an imidazole ring that has been described as an antiprotozoal agent with antiparasitic properties and less toxicity. Thiazolidinone derivatives have been reportedly as building blocks in organic chemistry and as scaffolds for drug discovery. Here we present a perspective of how structural modifications of the thiazolidinone core could generate new compounds with high anti-parasitic effect and less toxic results.

A rational approach to select immunogenic peptides that induce IFN-γ response against Toxoplasma gondii in human leukocytes.

The ideal vaccine to prevent toxoplasmosis in humans would comprise antigens that elicit a protective T cell type 1 response with high IFN-γ production. Here, we report the use of a bioinformatics pipeline to discover peptides based on biochemical characteristics that predict strong IFN-γ response by human leukocytes. We selected peptide sequences that previously were reported to induce IFN-γ to identify the biophysical characteristics that will predict HLA-A*02 high-affinity epitopes. We found that the protein motif pattern FL...L..[VL] was common in previously reported highly immunogenic sequences. We have selected new peptides with a length of 9 residues with affinities from 2 to 21 nM with peptide signal and transmembrane domains and predicted to be cleaved at the proteasome to perform ELISPOT assays with human leukocytes. Within 9 peptides with the highest scores for IFN-γ production, four peptides elicited IFN-γ levels in a range from 252 to 1763 SFC/1e6. Our pipeline uncovered Toxoplasma proteins with peptides that are processed by MHC class 1 in humans. Our results suggest that our rational strategy for the selection of immunogenic epitopes could be used to select peptides as candidates for inclusion in epitope-based vaccines.

Toxoplasma gondii: P30 peptides recognition pattern in human toxoplasmosis.

In this study, human sera reactivity against nine peptides derived from the Toxoplasma gondii P30 protein was assessed by ELISA in patients with different clinical forms of toxoplasmosis. Same as has been reported in mice, sera from congenital, ocular and chronic asymptomatic toxoplasmosis patients recognized more strongly peptides from the protein's carboxy-terminus, being peptide 2017 (amino acids 301-320) the one most strongly recognized by sera from patients with ocular toxoplasmosis. Serum samples collected from 13 patients without ocular infection, 13 with inactive chorioretinal scars, 6 with active ocular infection and 10 seronegative individuals were then screened for anti-2017 IgG. Peptide 2017 was recognized by all patients' samples but not by sera from T. gondii-seronegative individuals. No statistically significant differences were found between the absorbance levels of groups with and without lesions or with active or inactive ocular lesions, as determined by ANOVA.