Alteraciones en la tasa de respiración de Daphnia magna bajo concentraciones subletales de anatoxina-a

Anatoxina-a es una potente neurotoxina producida por cianobacterias dulceacuícolas que puede representar un riesgo, por sus efectos agudos, para diferentes formas de vida, incluyendo los seres humanos. Aunque se conocen los efectos agudos y crónicos de esta toxina, pocos estudios aportan datos de medidas de efectos subletales sobre la respiración del zooplancton. En este trabajo se cuantifican cambios en la respiración de Daphnia magna bajo una concentración subletal de anatoxina-a, en condiciones experimentales, por medio de un sistema automatizado de medida en continuo de consumo de Oxígeno. Los resultados indican que la presencia de anatoxina-a en dosis subletales reduce significativamente la actividad respiratoria en esta especie, con efectos, dependientes de la edad del organismo.Anatoxin-a is a potent neurotoxin produced by some freshwater cyanobacteria which, because of its acute toxic effects, may represent a hazard to aquatic organisms, and even to human beings. Both the acute and chronic effects of this toxin are rather well known, but few studies provided information about its sublethal effect on the zooplankton respiration. In this paper we have quantified respiration changes in Daphnia magna under sublethal anatoxin-a concentrations in experimental conditions, using an automatic open-flow system of continuous measurement of oxygen consumption. Our results show that the presence of anatoxin-a at sublethal doses reduces significantly the respiratory activity of the animals, being the effects greatly dependent on the individual age

Phytoestrogen agathisflavone ameliorates neuroinflammation-induced by LPS and IL-1β and protects neurons in cocultures of glia/neurons

Inflammation and oxidative stress are common aspects of most neurodegenerative diseases in the central nervous system. In this context, microglia and astrocytes are central to mediating the balance between neuroprotective and neurodestructive mechanisms. Flavonoids have potent anti-inflammatory and antioxidant properties. Here, we have examined the anti-inflammatory and neuroprotective potential of the flavonoid agathisflavone (FAB), which is derived from the Brazilian plant Poincianella pyramidalis, in in vitro models of neuroinflammation. Cocultures of neurons/glial cells were exposed to lipopolysaccharide (LPS, 1 µg/mL) or interleukin (IL)-1β (10 ng/mL) for 24 h and treated with FAB (0.1 and 1 µM, 24 h). FAB displayed a significant neuroprotective effect, as measured by nitric oxide (NO) production, Fluoro-Jade B (FJ-B) staining, and immunocytochemistry (ICC) for the neuronal marker β-tubulin and the cell death marker caspase-3, preserving neuronal soma and increasing neurite outgrowth. FAB significantly decreased the LPS-induced microglial proliferation, identified by ICC for Iba-1/bromodeoxyuridine (BrdU) and CD68 (microglia M1 profile marker). In contrast, FAB had no apparent effect on astrocytes, as determined by ICC for glial fibrillary acidic protein (GFAP). Furthermore, FAB protected against the cytodestructive and proinflammatory effects of IL-1β, a key cytokine that is released by activated microglia and astrocytes, and ICC showed that combined treatment of FAB with α and β estrogen receptor antagonists did not affect NF-κB expression. In addition, qPCR analysis demonstrated that FAB decreased the expression of proinflammatory molecules TNF-α, IL-1β, and connexins CCL5 and CCL2, as well as increased the expression of the regulatory molecule IL-10. Together, these findings indicate that FAB has a significant neuroprotective and anti-inflammatory effect in vitro, which may be considered as an adjuvant for the treatment of neurodegenerative diseases

Neuroimmunomodulatory and neuroprotective effects of the flavonoid apigenin in in vitro models of neuroinflammation associated with Alzheimer's disease

Neurodegenerative disorders (ND) are characterized by the progressive and irreversible loss of neurons. Alzheimer’s Disease (AD) is the most incident age-related ND, in which the presence of a chronic inflammatory compound seems to be related to its pathogenesis. Different stimuli in the central nervous system (CNS) can induce activation, proliferation, and changes in phenotype and glial function, which can be modulated by anti-inflammatory agents. Apigenin (4,5,7–trihydroxyflavone) is a flavonoid found in abundance in many fruits and vegetables, that has shown important effects upon controlling the inflammatory response. This study evaluated the neuroprotective and neuroimmunomodulatory potential of apigenin using in vitro models of neuroinflammation associated with AD. Co-cultures of neurons and glial cells were obtained from the cortex of newborn and embryonic Wistar rats. After 26 days in vitro, cultures were exposed to lipopolysaccharide (LPS; 1 μg/ml), or IL-1β (10 ng/ml) for 24 h, or to Aβ oligomers (500 nM) for 4 h, and then treated with apigenin (1 μM) for further 24 h. It was observed that the treatment with apigenin preserved neurons and astrocytes integrity, determined by Rosenfeld’s staining and immunocytochemistry for β-tubulin III and GFAP, respectively. Moreover, it was observed by Fluoro-Jade-B and caspase-3 immunostaining that apigenin was not neurotoxic and has a neuroprotective effect against inflammatory damage. Additionally, apigenin reduced microglial activation, characterized by inhibition of proliferation (BrdU+ cells) and modulation of microglia morphology (Iba-1 + cells), and decreased the expression of the M1 inflammatory marker CD68. Moreover, as determined by RT-qPCR, inflammatory stimuli induced by IL-1β increased the mRNA expression of IL-6, IL-1β, and CCL5, and decreased the mRNA expression of IL-10. Contrary, after treatment with apigenin in inflammatory stimuli (IL-1β or LPS) there was a modulation of the mRNA expression of inflammatory cytokines, and reduced expression of OX42, IL-6 and gp130. Moreover, apigenin alone and after an inflammatory stimulus with IL-1β also induced the increase in the expression of brain-derived neurotrophic factor (BDNF), an effect that may be associated with anti-inflammatory and neuroprotective effects. Together these data demonstrate that apigenin presents neuroprotective and anti-inflammatory effects in vitro and might represent an important neuroimmunomodulatory agent for the treatment of neurodegenerative conditions

ALTERAÇÕES MORFOLÓGICAS DE LEUCÓCITOS E TROMBÓCITOS SANGUÍNEOS EM Piaractus mesopotamicus DURANTE A SEPSE

Sepsis is defined as organ dysfunction with high mortality. During this process, the hematological system plays a critical role. Thus, the work aimed to analyze the morphological changes in the leukogram and thrombogram by the indirect method in the course of sepsis in Piaractus mesopotamicus. For this, 98 pacus were used, divided into two groups, one received 0.5 ml of sterile 0.65% sodium chloride solution (control) and the other received the same volume containing the bacterial inoculum (1.8 x 108 CFU/ml – challenge). To assess such changes in the evolution of sepsis, blood samples were collected from fish 1, 3, 6 and 9 hours after inoculation and in the control group (n = 10). One aliquot of the blood was used for blood culture and another for determining the number of leukocytes and thrombotics by the indirect method and the evaluation of morphological changes in blood extensions. Aeromonosis was confirmed by positive blood culture in all samples from the challenged groups. The leukogram analysis showed a significant increase (p <0.05) of leukocytes in the later times, 9 and 6 HPI in relation to the control group. Differential analysis showed leukopenia (p <0.05; 3 HPI) and consumption of thrombocytes. It was found that with the increase of the infection the septicemic pacus develops a picture of granulocytosis and monocytosis (p <0.05). It was concluded that inoculation with A. hydrophila induced sepsis with positive blood culture with leukocytosis in the challenged pacus and caused an intense change in the leukocyte and thrombotic morphology.KEYWORDS: Hemoculture, Leukogram, Morphology, Aeromonas hydrophila, Teleosts.La sepsis se define como disfunción orgánica con alta mortalidad. Durante este proceso, el sistema hematológico juega un papel crítico. Por lo tanto, el trabajo tuvo como objetivo analizar los cambios morfológicos en el leucograma y el trombograma por el método indirecto en el curso de la sepsis en Piaractus mesopotamicus. Para esto, se utilizaron 98 pacus, divididos en dos grupos, uno recibió 0,5 ml de solución estéril de cloruro de sodio al 0,65% (control) y el otro recibió el mismo volumen que contenía el inóculo bacteriano (1,8 x 108 UFC / ml - desafío). Para evaluar dichos cambios en la evolución de la sepsis, se recogieron muestras de sangre de peces 1, 3, 6 y 9 horas después de la inoculación y en el grupo de control (n = 10). Una parte alícuota de la sangre se usó para el hemocultivo y otra para determinar el número de leucocitos y trombóticos mediante el método indirecto y la evaluación de los cambios morfológicos en las extensiones de sangre. La aeromonosis se confirmó por hemocultivo positivo en todas las muestras de los grupos desafiados. El análisis de leucogramas mostró un aumento significativo (p <0.05) de leucocitos en los últimos tiempos, 9 y 6 HPI en relación con el grupo de control. El análisis diferencial mostró leucopenia (p <0.05; 3 HPI) y consumo de trombocitos. Se encontró que con el aumento de la infección, el pacus septicémico desarrolla una imagen de granulocitosis y monocitosis (p <0.05). Se concluyó que la inoculación con A. hydrophila indujo sepsis con hemocultivo positivo con leucocitosis en pacus desafiado y causa un cambio intenso en los leucocitos y la morfología trombóticaPALABRAS CLAVES Hemocultivo, Leucograma, Morfología, Aeromonas hydrophila, Teleósteos.A sepse é definida como disfunção orgânica com alta mortalidade. Durante esse processo o sistema hematológico desempenha um papel crítico. Assim, o trabalho objetivou analisar as alterações morfológicas no leucograma e no trombograma pelo método indireto no curso da sepse em Piaractus mesopotamicus. Para tanto, foram utilizados 98 pacus, divididos em dois grupos, um deles recebeu 0,5 ml de solução de cloreto de sódio esterilizada a 0,65% (controle) e outro recebeu o mesmo volume contendo o inoculo bacteriano (18 x 108 CFU/ml – desafio). Para avaliar tais alterações na evolução da sepse foram realizadas coletas de sangue dos peixes 1, 3, 6 e 9 horas após inoculação e no grupo controle (n=10). Uma alíquota do sangue foi destina a hemocultura e outra na determinação do número de leucócitos e de trombóticos pelo método indireto e a avaliação das alterações morfológicas nas extensões sanguíneas. A aeromonose foi confirmada pela hemocultura positiva em todas as amostras dos grupos desafiados. A análise do leucograma demonstrou aumento significativa (p<0,05) dos leucócitos nos tempos mais tardios, 9 e 6 HPI em relação ao grupo controle. Da análise diferencial observou-se leucopenia (p<0,05; 3 HPI) e consumo dos trombócitos. Verificou-se que com o aumento da infecção os pacus septicêmicos desenvolvem um quadro de granulocitose e monocitose (p<0,05). Concluiu-se que a inoculação com A. hydrophila induziu a sepse com hemocultura positiva com leucocitose nos pacus desafiados e causa intensa alteração na morfologia dos leucócitos e trombóticos.PALAVRAS-CHAVE: Hemocultura, Leucograma, Morfologia, Aeromonas hydrophila, Teleósteos

Genomic exploration of sequential clinical isolates reveals a distinctive molecular signature of persistent Staphylococcus aureus bacteraemia.

Large-scale genomic studies of within-host diversity in Staphylococcus aureus bacteraemia (SAB) are needed to understanding bacterial adaptation underlying persistence and thus refining the role of genomics in management of SAB. However, available comparative genomic studies of sequential SAB isolates have tended to focus on selected cases of unusually prolonged bacteraemia, where secondary antimicrobial resistance has developed. To understand bacterial genetic diversity during SAB more broadly, we applied whole genome sequencing to a large collection of sequential isolates obtained from patients with persistent or relapsing bacteraemia. After excluding genetically unrelated isolates, we performed an in-depth genomic analysis of point mutations and chromosome structural variants arising within individual SAB episodes. We show that, while adaptation pathways are heterogenous and episode-specific, isolates from persistent bacteraemia have a distinctive molecular signature, characterised by a low mutation frequency and high proportion of non-silent mutations. Analysis of structural genomic variants revealed that these often overlooked genetic events are commonly acquired during SAB. We discovered that IS256 insertion may represent the most effective driver of within-host microevolution in selected lineages, with up to three new insertion events per isolate even in the absence of other mutations. Genetic mechanisms resulting in significant phenotypic changes, such as increases in vancomycin resistance, development of small colony phenotypes, and decreases in cytotoxicity, included mutations in key genes (rpoB, stp, agrA) and an IS256 insertion upstream of the walKR operon. This study provides for the first time a large-scale analysis of within-host genomic changes during invasive S. aureus infection and describes specific patterns of adaptation that will be informative for both understanding S. aureus pathoadaptation and utilising genomics for management of complicated S. aureus infections

Corrosion resistance and antibacterial properties of copper coating deposited by cold gas spray

This work describes the morphology, corrosion resistance, and antibacterial performance of copper coating deposited onto carbon steel by cold gas spray (CGS). Cross-sectional images of the coating showed a dense microstructure, with porosity lower than 1%. XRD analysis revealed no oxides or phases different to pure copper. The results of electrochemical tests demonstrated the efficient barrier properties and the compact microstructure of the coating, which protected the substrate against corrosion in chloride solution for > 1000 h. The copper coating was effective as an antimicrobial agent for inhibiting the growth of Staphylococcus aureus, with bacterial growth being completely inhibited after 10 min of direct contact between the bacteria and the coating surface

The flavonoid agathisflavone modulates the microglial neuroinflammatory response and enhances remyelination

Myelin loss is the hallmark of the demyelinating disease multiple sclerosis (MS) and plays a significant role in multiple neurodegenerative diseases. A common factor in all neuropathologies is the central role of microglia, the intrinsic immune cells of the central nervous system (CNS). Microglia are activated in pathology and can have both pro- and anti-inflammatory functions. Here, we examined the effects of the flavonoid agathisflavone on microglia and remyelination in the cerebellar slice model following lysolecithin induced demyelination. Notably, agathisflavone enhances remyelination and alters microglial activation state, as determined by their morphology and cytokine profile. Furthermore, these effects of agathisflavone on remyelination and microglial activation were inhibited by blockade of estrogen receptor α. Thus, our results identify agathisflavone as a novel compound that may act via ER to regulate microglial activation and enhance remyelination and repair

On spin-1 massive particles coupled to a Chern-Simons field

We study spin one particles interacting through a Chern-Simons field. In the Born approximation, we calculate the two body scattering amplitude considering three possible ways to introduce the interaction: (a) a Proca like model minimally coupled to a Chern-Simons field, (b) the model obtained from (a) by replacing the Proca's mass by a Chern-Simons term and (c) a complex Maxwell-Chern-Simons model minimally coupled to a Chern-Simons field. In the low energy regime the results show similarities with the Aharonov-Bohm scattering for spin 1/2 particles. We discuss the one loop renormalization program for the Proca's model. In spite of the bad ultraviolet behavior of the matter field propagator, we show that, up to one loop the model is power counting renormalizable thanks to the Ward identities satisfied by the interaction vertices.Comment: 14 pages, 5 figures, revte