Effect of Virulence Factors on the Photodynamic Inactivation of Cryptococcus neoformans

Opportunistic fungal pathogens may cause an array of superficial infections or serious invasive infections, especially in immunocompromised patients. Cryptococcus neoformans is a pathogen causing cryptococcosis in HIV/AIDS patients, but treatment is limited due to the relative lack of potent antifungal agents. Photodynamic inactivation (PDI) uses the combination of non-toxic dyes called photosensitizers and harmless visible light, which produces singlet oxygen and other reactive oxygen species that produce cell inactivation and death. We report the use of five structurally unrelated photosensitizers (methylene blue, Rose Bengal, selenium derivative of a Nile blue dye, a cationic fullerene and a conjugate between poly-L-lysine and chlorin(e6)) combined with appropriate wavelengths of light to inactivate C. neoformans. Mutants lacking capsule and laccase, and culture conditions that favoured melanin production were used to probe the mechanisms of PDI and the effect of virulence factors. The presence of cell wall, laccase and melanin tended to protect against PDI, but the choice of the appropriate photosensitizers and dosimetry was able to overcome this resistance.Fundação de Amparo à Pesquisa do Estado de São Paulo (2010/13313–9

Parameters for antimicrobial photodynamic therapy on periodontal pocket-Randomized clinical trial.

BACKGROUND: Antimicrobial photodynamic therapy (aPDT) has been investigated as an adjunctive to periodontal treatment but the dosimetry parameters adopted have discrepancies and represent a challenge to measure efficacy. There is a need to understand the clinical parameters required to obtain antimicrobial effects by using aPDT in periodontal pockets. The aim of this study was to investigate parameters relating to the antimicrobial effects of photodynamic therapy in periodontal pockets. MATERIAL AND METHODS: This randomized controlled clinical trial included 30 patients with chronic periodontitis. Three incisors from each patient were selected and randomized for the experimental procedures. Microbiological evaluations were performed to quantify microorganisms before and after treatments and spectroscopy was used to identify methylene blue in the pocket. A laser source with emission of radiation at wavelength of ʎ = 660 nm and output radiant power of 100 mW was used for 1, 3 and 5 min. One hundred μM methylene blue was used in aqueous solution and on surfactant vehicle. RESULTS: The results demonstrated the absence of any antimicrobial effect with aqueous methylene blue-mediated PDT. On the other hand, methylene blue in the surfactant vehicle produced microbial reduction in the group irradiated for 5 min (p < 0.05). Spectroscopy showed that surfactant vehicle decreased the dimer peak signal at 610 nm. CONCLUSION: Within the parameters used in this study, PDT mediated by methylene blue in a surfactant vehicle reached significant microbial reduction levels with 5 min of irradiation. The clinical use of PDT may be limited by factors that reduce the antimicrobial effect. Forms of irradiation and stability of the photosensitizers play an important role in clinical aPDT

Antimicrobial photodynamic therapy mediated by methylene blue in surfactant vehicle on periodontopathogens

Background: Periodontal disease (PD) is a chronic inflammatory disease caused by the presence of microbial biofilm. The aim of this study was to evaluate antimicrobial effect of antimicrobial photodynamic therapy (A-PDT) mediated by methylene blue (MB) in monomer form on A. actinomycetemcomitans and P. gingivalis. Methods: A. actinomycetemcomitans ATCC 29523 and P. gingivalis ATCC 33577 were cultured on anaerobic jars at 37 °C for 48 h, and we tested APDT in the presence of 0.25% sodium dodecyl sulfate (SDS) in phosphate-buffered saline (PBS) or in PBS alone. APDT was carried out with 100 μM MB under laser radiation (PhotolaseIII, DMC, Brazil) at ʎ =660 nm and parameters as following (P =100 mW; I =250 mW/cm2, and doses of 15, 45 and 75 J/cm2). Results: Following A-PDT, PBS groups of A. actinomycetemcomitans presented 4 Logs of microbial death after 5 min irradiation. However, there was no bacterial reduction in SDS groups. On the other hand, P. gingivalis was sensitive to APDT in the presence of 0.25% SDS with 2 logs reduction from dark toxicity. Conclusion: The presence of 0.25% SDS can lead to different responses depending on the different microbial species. © 2020 Elsevier B.V

Comparative study between photodynamic therapy with urucum + Led and probiotics in halitosis reduction-protocol for a controlled clinical trial.

BACKGROUND: Halitosis is a term that defines any foul odor emanating from the oral cavity. The origin may be local or systemic. The aim of the proposed protocol is to determine whether treatment with antimicrobial photodynamic therapy (aPDT) and treatment with probiotics are effective at eliminating halitosis. MATERIALS AND METHODS: Eighty-eight patients, from 18 to 25 years old with a diagnosis of halitosis (H2S≥112 ppb, determined by gas chromatography) will be randomly allocated to four groups (n = 22) that will receive different treatments: Group 1 -treatment with teeth brushing, dental floss and tongue scraper; Group 2 -brushing, dental floss and aPDT; Group 3 -brushing, dental floss and probiotics; Group 4 -brushing, flossing, aPDT and probiotics. The results of the halimetry will be compared before, immediately after, seven days and thirty days after treatment. The microbiological analysis of the coated tongue will be performed at these same times. The normality of the data will be determined using the Shapiro-Wilk test. Data with normal distribution will be analyzed using analysis of variance (ANOVA). Non-parametric data will be analyzed using the Kruskal-Wallis test. The Wilcoxon test will be used to analyze the results of each treatment at the different evaluation periods. CLINICAL TRAIL REGISTRATION: NCT03996044

Spatial Pattern of Standing Timber Value across the Brazilian Amazon

The Amazon is a globally important system, providing a host of ecosystem services from climate regulation to food sources. It is also home to a quarter of all global diversity. Large swathes of forest are removed each year, and many models have attempted to predict the spatial patterns of this forest loss. The spatial patterns of deforestation are determined largely by the patterns of roads that open access to frontier areas and expansion of the road network in the Amazon is largely determined by profit seeking logging activities. Here we present predictions for the spatial distribution of standing value of timber across the Amazon. We show that the patterns of timber value reflect large-scale ecological gradients, determining the spatial distribution of functional traits of trees which are, in turn, correlated with timber values. We expect that understanding the spatial patterns of timber value across the Amazon will aid predictions of logging movements and thus predictions of potential future road developments. These predictions in turn will be of great use in estimating the spatial patterns of deforestation in this globally important biome

Microalgae Schizochytrium sp. in diets for Piau juvenilles

Todos os textos, informa??es e resultados apresentados s?o de inteira responsabilidade dos autores.O DHA ? um ?cido importante da s?rie ?mega 3, fundamental para a forma??o do tecido nervoso e visual em humanos, e confere tamb?m uma boa forma??o da massa encef?lica. O presente trabalho teve o objetivo de avaliar dietas contendo a inclus?o da alga Schizochytrium sp. no desempenho produtivo de juvenis de piau.O experimento foi conduzido no Laborat?rio de Aquicultura e Ecologia Aqu?tica do Departamento de Zootecnia da Universidade Federal dos Vales do Jequitinhonha e Mucuri, em Diamantina MG. Foram utilizados 300 juvenis de Piau (Leporinus friderici) com peso e comprimento total m?dio de 11,8 e 9,68 g respectivamente . Os peixes passaram por sete dias de adapta??o e foram alimentados com a ra??o do tratamento controle. . O experimento foi realizado em um delineamento inteiramente casualizado, com cinco tratamentos (0, 10, 20, 30, e 40 g de Schizochytrium sp/kg-1)e quatro repeti??es. Sete juvenis foram estocados por aqu?rio, totalizando 20 parcelas experimentais. Avaliou-se aos 60 dias de experimento par?metros de desempenho produtivo. Foram mensurados: comprimento padr?o (cm), comprimento total (cm), ganho de peso (g), consumo de ra??o (g), convers?o alimentar (g/g)?, biomassa final (g), e sobreviv?ncia (%). As vari?veis de desempenho apresentaram melhores resultados de acordo com o aumento do n?vel de inclus?o da alga Schizochytrium sp em juvenis de piau. Conlcui-se com este estudo que juvenis de piau alimentados com 40g de Schizochytrium sp.kg-1 apresentam melhor desempenho produtivo e sobreviv?ncia.DHA is an important acid of the omega-3 series, essential for the formation of the nervous and visual tissue in humans, and also gives a good formation of brain matter. This study aimed to evaluate diets with the inclusion of algae Schizochytrium sp. In productive performance of piau juveniles.. Experiment was conducted at the Aquaculture Laboratory of Aquatic Ecology of the Department of Animal Science, of the Federal University of the Jequitinhonha and Mucuri Valleys, in Diamantina MG. . Three hundred Piau (Leporinus friderici) juvenile, with body weight and length means of 11.8, and 9.68 g respectively. Fish have undergone seven days of adaptation and were fed with the control ration treatment. The experiment was conducted in a completely randomized design, with five treatments (0, 10, 20, 30, and 40 g of Schizochytrium sp. Kg-1) and four replications. Seven juveniles were stocked per aquarium, totaling 20 experimental plots. It was evaluated at 60 days of the experiment For the productive performance were measured: standard length (cm), total length (cm), weight gain (g), feed intake (g), feed conversion (g / g) ? , final biomass (g) EC (%) and survival (%). The performance variables showed greater results in accordance with the increase in the level of inclusionof Schizochytrium sp in piau juveniles diets. It follows that piau juveniles fed with 40g Schizochytrium sp.kg-1 have greater growth performance and survival

Cooperation between Apoptotic and Viable Metacyclics Enhances the Pathogenesis of Leishmaniasis

Mimicking mammalian apoptotic cells by exposing phosphatidylserine (PS) is a strategy used by virus and parasitic protozoa to escape host protective inflammatory responses. With Leishmania amazonensis (La), apoptotic mimicry is a prerogative of the intramacrophagic amastigote form of the parasite and is modulated by the host. Now we show that differently from what happens with amastigotes, promastigotes exposing PS are non-viable, non-infective cells, undergoing apoptotic death. As part of the normal metacyclogenic process occurring in axenic cultures and in the gut of sand fly vectors, a sub-population of metacyclic promastigotes exposes PS. Apoptotic death of the purified PS-positive (PSPOS) sub-population was confirmed by TUNEL staining and DNA laddering. Transmission electron microscopy revealed morphological alterations in PSPOS metacyclics such as DNA condensation, cytoplasm degradation and mitochondrion and kinetoplast destruction, both in in vitro cultures and in sand fly guts. TUNELPOS promastigotes were detected only in the anterior midgut to foregut boundary of infected sand flies. Interestingly, caspase inhibitors modulated parasite death and PS exposure, when added to parasite cultures in a specific time window. Efficient in vitro macrophage infections and in vivo lesions only occur when PSPOS and PS-negative (PSNEG) parasites were simultaneously added to the cell culture or inoculated in the mammalian host. The viable PSNEG promastigote was the infective form, as shown by following the fate of fluorescently labeled parasites, while the PSPOS apoptotic sub-population inhibited host macrophage inflammatory response. PS exposure and macrophage inhibition by a subpopulation of promastigotes is a different mechanism than the one previously described with amastigotes, where the entire population exposes PS. Both mechanisms co-exist and play a role in the transmission and development of the disease in case of infection by La. Since both processes confer selective advantages to the infective microorganism they justify the occurrence of apoptotic features in a unicellular pathogen

The spatial structure of lithic landscapes : the late holocene record of east-central Argentina as a case study

Fil: Barrientos, Gustavo. División Antropología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Catella, Luciana. División Arqueología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Oliva, Fernando. Centro Estudios Arqueológicos Regionales. Facultad de Humanidades y Artes. Universidad Nacional de Rosario; Argentin