Design and functional characterization of Salmo salar TLR5 agonist peptides derived from high mobility group B1 acidic tail.

Toll-like receptor 5 (TLR5) responds to the monomeric form of flagellin and induces the MyD88-depending signaling pathway, activating proinflammatory transcription factors such as NF-κB and the consequent induction of cytokines. On the other hand, HMGB1 is a highly conserved non-histone chromosomal protein shown to interact with and activate TLR5. The present work aimed to design and characterize TLR5 agonist peptides derived from the acidic tail of Salmo salar HMGB1 based on the structural knowledge of the TLR5 surface using global molecular docking platforms. Peptide binding poses complexed on TLR5 ectodomain model from each algorithm were filtrated based on docking scoring functions and predicted theoretical binding affinity of the complex. Circular dichroism spectra were recorded for each peptide selected for synthesis. Only intrinsically disordered peptides (6W, 11W, and SsOri) were selected for experimental functional assay. The functional characterization of the peptides was performed by NF-κB activation assays, RT-qPCR gene expression assays, and Piscirickettsia salmonis challenge in SHK-1 cells. The 6W and 11W peptides increased the nuclear translation of p65 and phosphorylation. In addition, the peptides induced the expression of genes related to the TLR5 pathway activation, pro- and anti-inflammatory response, and differentiation and activation of T lymphocytes towards phenotypes such as TH1, TH17, and TH2. Finally, it was shown that the 11W peptide protects immune cells against infection with P. salmonis bacteria. Overall, the results indicate the usefulness of novel peptides as potential immunostimulants in salmonids.

Isolation, characterization, and immunomodulatory activity evaluation of probiotic strains from colostrum and canine milk.

Background: This study aimed to characterize potential probiotic strains for use in dogs to prevent infectious enteropathies. Lactic acid bacteria (LAB) isolated from canine milk and colostrum were characterized according to their functional properties, including their resistance to gastrointestinal conditions, inhibitory effect against pathogens, and intestinal adhesion. Methods: The immunomodulatory effects of the strains were also analyzed in in vitro and in vivo studies. Among the strains evaluated, two LAB strains (TUCO-16 and TUCO-17) showed remarkable resistance to pH 3.0, bile salts, and pancreatin, as well as inhibitory effects against pathogenic Escherichia coli, Salmonella sp., and Clostridium perfringens. Results: The TUCO-16 and TUCO-17 strains induced a significant increase in the expression of TNF-α, IL-8, and TLR2 in canine macrophages. The oral administration of TUCO-16 and TUCO-17 strains to mice significantly augmented their resistance to pathogenic E. coli or Salmonella intestinal infections. Both canine strains reduced intestinal damage and pathogen counts in the liver and spleen and avoided their dissemination into the bloodstream. These protective effects were related to the ability of TUCO-16 and TUCO-17 strains to differentially modulate the production of IFN-γ, IFN-ß, TNF-α, IL-6, KC, MCP-1, and IL-10 in the intestinal mucosa. Conclusion: Both strains, TUCO-16 and TUCO-17, are potential probiotic candidates for improving intestinal health in dogs, particularly for their ability to inhibit the growth of Gram-negative pathogens common in gastrointestinal infections and modulate the animal's immune response. Further studies are required to effectively demonstrate the beneficial effects of TUCO-16 and TUCO-17 strains in dogs.

The AO classification system for tibial plateau fractures: An independent inter and intraobserver agreement study.

PURPOSE: Classifying tibial plateau fractures is paramount in determining treatment regimens and systemizing decision making. The original AO classification described by Müller in 1996 and the Schatzker classification of 1970 are the most cited classifications for tibial plateau fractures, demonstrating substantial to almost perfect agreement. The main problem with these classifications schemes is that they lack the detail required to convey the variety of fracture patterns encountered. In 2018, the AO foundation published a new classification system for proximal tibia fractures, highlighting a more complete and detailed number of categories and subcategories. We sought to independently determine inter and intraobserver agreement of the AO classification system, compared to the previous systems described by Müller and Schatzker. METHODS: One hundred seven consecutive tibial plateau fractures were screened, and a representative data set of 69 was created. Six independent evaluators (three knee surgeons, three senior orthopedic residents) classified the fractures using the original AO, the Schatzker and the new AO classifications. After six weeks, the 69 cases were randomized and reclassified by all evaluators. The Kappa coefficient (k) was calculated for inter- and intraobserver correlation and is expressed with 95% confidence intervals. RESULTS: interobserver agreement was moderate for all three classifications. k = 0.464 (0.383-0.560) for the original AO; k = 0.404 (0.337-0.489) for Schatzker; and k = 0.457 (0.371-0.545) for the base categories of the new AO classification. The inclusion of subcategories and letter modifiers to the new classification worsened agreement to k = 0.358 (0.302-0.423) and k = 0.174 (0.134-0.222), respectively. There were no significant differences between knee surgeons and residents for the new classification. Intra-observer correlation was also moderate for each of the scores: k = 0.630 (0.578-0.682) for the original AO; k = 0.623 (0.569-0.674) for Schatzker; and k = 0.621 (0.566-0.678) for the new AO base categories; without differences between knee surgeons or residents. CONCLUSIONS: This study demonstrated an adequate inter and intra-observer agreement for the new AO tibial plateau fractures classification system for its base categories, but not at the subcategory or letter modifier levels.

Chitosan Microparticles Enhance the Intestinal Release and Immune Response of an Immune Stimulant Peptide in Oncorhynchus mykiss.

The aquaculture industry is constantly increasing its fish production to provide enough products to maintain fish consumption worldwide. However, the increased production generates susceptibility to infectious diseases that cause losses of millions of dollars to the industry. Conventional treatments are based on antibiotics and antivirals to reduce the incidence of pathogens, but they have disadvantages, such as antibiotic resistance generation, antibiotic residues in fish, and environmental damage. Instead, functional foods with active compounds, especially antimicrobial peptides that allow the generation of prophylaxis against infections, provide an interesting alternative, but protection against gastric degradation is challenging. In this study, we evaluated a new immunomodulatory recombinant peptide, CATH-FLA, which is encapsulated in chitosan microparticles to avoid gastric degradation. The microparticles were prepared using a spray drying method. The peptide release from the microparticles was evaluated at gastric and intestinal pH, both in vitro and in vivo. Finally, the biological activity of the formulation was evaluated by measuring the expression of il-1ß, il-8, ifn-γ, Ifn-α, and mx1 in the head kidney and intestinal tissues of rainbow trout (Oncorhynchus mykiss). The results showed that the chitosan microparticles protect the CATH-FLA recombinant peptide from gastric degradation, allowing its release in the intestinal portion of rainbow trout. The microparticle-protected CATH-FLA recombinant peptide increased the expression of il-1ß, il-8, ifn-γ, ifn-α, and mx1 in the head kidney and intestine and improved the antiprotease activity in rainbow trout. These results suggest that the chitosan microparticle/CATH-FLA recombinant peptide could be a potential prophylactic alternative to conventional antibiotics for the treatment of infectious diseases in aquaculture.

Repercusiones vocales tras el uso ocupacional de la voz y estrés en profesoras de primaria bajo la modalidad de teletrabajo en la comuna de Temuco. Un estudio piloto / Vocal Repercussions after Occupational Voice Use and Stress in Primary School Teachers under the Teleworking Modality in Temuco City. A Pilot Study

Introducción. El teletrabajo producto del COVID-19 ha generado exigencias que podrían promover la generación de un sobreesfuerzo vocal. Objetivo. Evaluar cómo las condiciones de trabajo pueden afectar la salud vocal, evaluar el estrés laboral y valorar los cambios en la calidad vocal de profesoras de primaria de la comuna de Temuco.Método. Se evaluó a 18 profesoras de primaria de la comuna de Temuco, Chile, quienes se encontraban trabajando en modalidad de teletrabajo durante el año 2021, realizando una evaluación al comienzo y al final del año escolar, a través del Voice Handicap Index (VHI-30), Vocal Tract Disconfort (VTD), Maslach Burnout Inventory (MBI) y análisis acústico mediante medidas de perturbación y espectro promedio a largo plazo. Resultados. Solo el 21% de las profesoras contaba con un espacio físico adecuado para el teletrabajo. El 52,6% debía compartir responsabilidades del hogar, como el cuidado de hijos menores durante su jornada de teletrabajo. Los resultados muestran un aumento de la sintomatología y sensaciones de incomodidad a nivel del tracto vocal medidas mediante el VHI-30 y el VTD. En cuanto al estrés laboral medido por la escala de Burnout, solo se evidenció un valor significativo para la subescala agotamiento emocional. No se evidenciaron diferencias significativas en los parámetros acústicos Jitter, Shimmer, HNR y Alpha ratio. Conclusiones. La gran mayoría de las participantes manifestó un aumento del malestar y sintomatología vocal autopercibida (sequedad de garganta, fatiga vocal) en conjunto con un mayor nivel de estrés, lo que a la larga puede desencadenar trastornos de voz

Introduction. Teleworking as a result of COVID-19 has generated high demands that could promote the generation of vocal overexertion.Aim. To evaluate how working conditions assess changes in vocal health, evaluate work stress, and assess changes in the vocal quality of primary school teachers in the Temuco commune.Method. Eighteen elementary school teachers from the commune of Temuco, Chile, who were teleworking during the year 2021, were evaluated not only at the beginning but also at the end of the school year through the Voice Handicap Index (VHI-30), Vocal Tract Discomfort (VTD), Maslach Burnout Inventory (MBI), and acoustic analysis using long-term average spectrum and disturbance measurements.Results. Only 21% of the teachers had adequate physical space for teleworking. In addition, 52.6% had to share household responsibilities such as taking care of minor children during their teleworking day. The results show an increase in symptoms and sensations of discomfort at the level of the vocal tract measured by the VHI-30 and the VTD. Regarding job stress measured by the Burnout scale, only a significant value for the emotional exhaustion subscale was found. Besides, there were not found any significant differences in the acoustic parameters Jitter, Shimmer, HNR, and Alpha ratio.Conclusions. The vast majority of the participants reported increased discomfort and self-perceived vocal symptoms (dry throat, vocal fatigue) together with a higher level of stress, which in the long run can trigger voice disorders

Estudio preliminar para la validación de la versión chilena del Vocal Tract Discomfort-VTD en población docente / Validation of the chilean version of the Vocal Tract Discomfort-VTD on teachers: a preliminary study

Debido a la carga vocal a la que están expuestos los profesionales de la voz, como los profesores, son frecuentes los trastornos de voz y mal uso vocal en este grupo, lo que hace necesario poder contar con instrumentos de pesquisa rápidos y sencillos para un diagnóstico precoz de sintomatología vocal. El objetivo del presente estudio es realizar una adaptación y validación preliminar de la pauta "Vocal Tract Discomfort Scale (VTD)" al idioma español chileno en profesores. Se comenzó con la traducción al español del instrumento original por parte de dos expertos nativos y luego la retro-traducción por dos expertos en idioma inglés para determinar concordancias y discrepancias. Luego se continuó con la validación de apariencia y contenido realizada por valoración de grupo de expertos compuesto por dos metodólogos y cinco fonoaudiólogos con experiencia en el área vocal. La validez de criterio se obtuvo mediante la correlación entre la escala en estudio y el Voice Handicap Index en su versión validada al español como prueba gold-standard, para lo cual se aplicó en una muestra de 31 docentes. La validación de la escala VTD es fiable y deja a disposición de los fonoaudiólogos una herramienta sencilla y comprensible para el entendimiento del impacto generado en personas con disfonía, particularmente, en profesionales de la voz como los profesores.

Due to the vocal load to which voice professionals such as teachers are exposed, voice disorders and vocal misuse are frequently found in this group. This makes it necessary to have quick and simple assessment instruments that allow early detection of vocal symptoms. The objective of this study was to adapt the "Vocal Tract Discomfort Scale (VTD)" to Chilean Spanish and carry out a preliminary validation of this protocol on teachers. First, the original instrument was translated toSpanish by two native speakers, and then back-translated by two English experts, in order to determine the presence of agreements and discrepancies. Subsequently, a group of experts made up of two methodologists and five speech therapists with experience in the voice field performed an appearance and content validation. Criterion validity was obtained through the correlation between the Vocal Tract Discomfort Scale and the Spanish-validated version of the Voice Handicap Index as a gold-standard test, for which the first was appliedto a sample of 31 teachers. The validation of the VTD scale is reliable and provides speech therapists with a simple and understandable tool that allows them to comprehend the impact of dysphonia on people, particularly on voice professionals such as teachers.

New strategy for the design, production and pre-purification of chimeric peptide with immunomodulatory activity in Salmosalar.

The intensive salmon farming is associated with massive outbreaks of infections. The use of antibiotics for their prevention and control is related to damage to the environment and human health. Antimicrobial peptides (AMPs) have been proposed as an alternative to the use of antibiotics for their antimicrobial and immunomodulatory activities. However, one of the main challenges for its massive clinical application is the high production cost and the complexity of chemical synthesis. Thus, recombinant DNA technology offers a more sustainable, scalable, and profitable option. In the present study, using an AMPs function prediction methodology, we designed a chimeric peptide consisting of sequences derived from cathelicidin fused with the immunomodulatory peptide derived from flagellin. The designed peptide, CATH-FLA was produced by recombinant expression using an easy pre-purification system. The chimeric peptide was able to induce IL-1ß and IL-8 expression in Salmo salar head kidney leukocytes, and prevented Piscirickettsia salmonis-induced cytotoxicity in SHK-1 cells. These results suggest that pre-purification of a recombinant AMP-based chimeric peptide designed in silico allow obtaining a peptide with immunomodulatory activity in vitro. This could solve the main obstacle of AMPs for massive clinical applications.

Hip Fractures in the Elderly During the COVID-19 Pandemic: A Latin-American Perspective With a Minimum 90-Day Follow-Up.

INTRODUCTION: Hip fracture patients have been severely affected by the COVID-19 pandemic; however, the sub acute effects of a concomitant SARS-CoV-2 infection and the outcomes in highly exposed developing countries are still unknown. Our objective is to describe the morbidity and mortality of elderly patients admitted for a hip fracture during the COVID-19 pandemic in Chile, with a minimum 90-day follow-up. Also, to elucidate predictors for mortality and to compare mortality results with the pre-pandemic era. MATERIAL AND METHODS: Multicentric retrospective review of patients admitted for a fragility hip fracture in 3 hospitals during the COVID-19 pandemic, and during the same time in 2019. All clinical information and images were recorded, and patients were followed for a minimum of 90-days. Morbidity and mortality were the primary outcomes. Uni/multivariable models were performed to elucidate predictors for mortality utilizing the Weibull's regression. RESULTS: Three hundred ninety-one cases were included. From the 2020 cohort (162 patients), 24 (15%) had a concomitant SARS-CoV-2 infection. Fourteen patients (58%) tested positive after admission. The COVID-19(+) group had a higher risk of in-hospital, 30-day, and 90-day mortality (p < 0.001). They also had a prolonged hospital stay and presented with more complications and readmissions (p < 0.05). Only COVID-19(+) status and older age were independent predictors for mortality with a HR = 6.5 (p = < 0.001) and 1.09 (p = 0.001), respectively. The 2020 cohort had twice the risk of mortality with a HR = 2.04 (p = 0.002) compared to the 2019 cohort. However, comparing only the COVID-19 (-) patients, there was no difference in mortality risk, with a HR = 1.30 (p = 0.343). DISCUSSION: The COVID-19 pandemic has significantly affected healthcare systems and elderly patients. CONCLUSIONS: Hip fracture patients with a concomitant SARS-CoV-2 virus infection were associated with increased morbidity and mortality throughout the first 3 months. COVID-19 status and older age were significant predictors for mortality. Efforts should be directed into nosocomial infection reduction and prompt surgical management. LEVEL OF EVIDENCE: Level III.

The new AO classification system for intertrochanteric fractures allows better agreement than the original AO classification. An inter- and intra-observer agreement evaluation.

BACKGROUND: A new AO classification for intertrochanteric fractures was recently published; no studies have evaluated its inter- and intra-observer agreement. METHODS: Six evaluators (three hip subspecialists and three residents) assessed radiographs of 68 intertrochanteric fractures; fractures were classified using the original and the new AO classifications. The cases were displayed in a random sequence after a six-week interval for repeat evaluation. We used the Kappa coefficient (k) to determine inter- and intra-observer agreement. RESULTS: Inter-observer agreement was slight (k = 0.128 [0.092-0.170]) using the original and fair (k = 0.250 [0.186-0.327]), with the new AO classification. Orthopedic residents exhibited better agreement than hip surgeons using the original classification (k = 0.302 [0.210-0.416] and k= -0.018 [-0.058-0.029], respectively) and the new classification (k = 0.388 [0.294-0.514] and k = 0.109 [0.031-0.192], respectively). Using both classifications as dichotomous variables (stable or unstable patterns), the agreement was slight (k = 0.158 [0.074-0.246]) using the original classification and moderate (k = 0.425 [0.308-0.550]) with the new AO classification. INTRA-OBSERVER: The agreement was fair using the original (k = 0.350 [0.278-0.424]) and the new (k = 0.295 [0.239 to 0.353]) AO classifications, respectively. Residents had better agreement than hip specialists using the original (k = 0.405 [0.303-0.512]) versus (k = 0.292 [0.193-0.293]) and the new classification (k = 0.449 [0.370 to 0.528] versus k = 0.129 [0.064 to 0.208]). CONCLUSION: The inter-observer agreement using the new AO classification was significantly better than using its original version. Also, the new AO classification system allowed better agreement when distinguishing stable from unstable patterns.

The relationship between perceived social support and depressive symptoms in informal caregivers of community-dwelling older persons in Chile.

AIM: Depression among caregivers of older persons is a serious concern, but it is often overlooked and neglected in developing countries. The aim of this study was to examine the relationship between perceived social support and depression in informal caregivers of community-dwelling older persons in Chile. METHODS: We analyzed cross-sectional secondary data on 377 dyads of community-dwelling older persons and their informal caregivers from a nationwide survey in Chile. The Duke-UNC Functional Social Support Questionnaire (FSSQ) was used to measure caregivers' perceived social support, and the Center for Epidemiologic Studies Depression Scale assessed their depression. RESULTS: In this study, 76.9% of the caregivers perceived a high level of social support, and 46.9% were assessed as having depression. Based on multivariable analysis, factors that decrease the likelihood of being depressed are a high level of social support (odds ratio (OR) = 0.311, 95% confidence interval (CI): 0.167-0.579) and having taken holidays in the past 12 months (OR = 0.513, 95%CI: 0.270-0.975). Factors that increase the likelihood of being depressed are being a female caregiver (OR = 2.296, 95%CI: 1.119-4.707), being uninsured (OR = 4.321, 95%CI: 1.750-10.672), being the partner or spouse of the care recipient (OR = 3.832, 95%CI: 1.546-9.493), and the number of hours of care (OR = 1.053, 95%CI: 1.021-1.085). CONCLUSION: Higher levels of perceived social support and holidays were associated with lower levels of depression. However, being female, being the care recipient's partner or spouse, being uninsured, and having long care periods had detrimental effects. Interventions to preserve and enhance perceived social support could help improve depressive symptoms in informal caregivers. Additionally, support should be available to caregivers who are women, uninsured, and the care recipient's partner or spouse, as well as those who provide care for long hours, to ensure they have respite from their caregiving role.

Reconstrução de extenso defeito da parede torácica anterior pós-mediastinite com retalho de omento: relato de caso / Reconstruction of an extensive anterior chest wall defect after mediastinitis with an omentum flap: a case report

Apresentamos o caso de um paciente de 70 anos de idade que evoluiu com extenso defeito cutâneo em parede torácica anterior após ter sido submetido a revascularização do miocárdio e mediastinite pós-operatória. Pela impossibilidade de utilização de retalhos cutâneos e musculares da região, fizemos a reconstrução com a rotação de retalho de omento baseado na artéria gastroepiploica esquerda e enxerto de pele em malha.

We report the case of a 70-year-old patient who developed an extensive skin defect in the anterior chest wall after undergoing myocardial revascularization and postoperative mediastinitis. Owing to the impossibility of using cutaneous and muscular flaps on the region, we performed the reconstruction with an omentum flap based on the left gastroepiploic artery and meshed skin graft.

Detecting protein folding by thermal fluctuations of microcantilevers.

The accurate characterization of proteins in both their native and denatured states is essential to effectively understand protein function, folding and stability. As a proof of concept, a micro rheological method is applied, based on the characterization of thermal fluctuations of a micro cantilever immersed in a bovine serum albumin solution, to assess changes in the viscosity associated with modifications in the protein's structure under the denaturant effect of urea. Through modeling the power spectrum density of the cantilever's fluctuations over a broad frequency band, it is possible to implement a fitting procedure to accurately determine the viscosity of the fluid, even at low volumes. Increases in viscosity during the denaturant process are identified using the assumption that the protein is a hard sphere, with a hydrodynamic radius that increases during unfolding. This is modeled accordingly through the Einstein-Batchelor formula. The Einstein-Batchelor formula estimates are verified through dynamic light scattering, which measures the hydrodynamic radius of proteins. Thus, this methodology is proven to be suitable for the study of protein folding in samples of small size at vanishing shear stresses.

Rosmarinic acid prevents fibrillization and diminishes vibrational modes associated to ß sheet in tau protein linked to Alzheimer's disease.

Alzheimer's disease is a common tauopathy where fibril formation and aggregates are the hallmark of the disease. Efforts targeting amyloid-ß plaques have succeeded to remove plaques but failed in clinical trials to improve cognition; thus, the current therapeutic strategy is at preventing tau aggregation. Here, we demonstrated that four phenolic diterpenoids and rosmarinic acid inhibit fibrillization. Since, rosmarinic acid was the most active compound, we observe morphological changes in atomic force microscopy images after treatment. Hence, rosmarinic acid leads to a decrease in amide regions I and III, indicating that rosmarinic acid prevents ß-sheet assembly. Molecular docking study inside the steric zipper model of the hexapeptide 306VQIVYK311 involved in fibrillization and ß sheet formation, suggests that rosmarinic acid binds to the steric zipper with similar chemical interactions with respect to those observed for orange G, a known pharmacofore for amyloid.

Low thermal fluctuations in a system heated out of equilibrium.

We study the mechanical fluctuations of a micrometer sized silicon cantilever subjected to a strong heat flow, thus having a highly nonuniform local temperature. In this nonequilibrium steady state, we show that fluctuations are equivalent to the thermal noise of a cantilever at equilibrium around room temperature, while its mean local temperature is several hundred degrees higher. Changing the mechanical dissipation by adding a coating to the cantilever, we recover the expected rise of fluctuations with the mean temperature. Our work demonstrates that inhomogeneous dissipation mechanisms can decouple the amplitude of thermal fluctuations from the average temperature. This property could be useful to understand out-of-equilibrium fluctuating systems, or to engineer low noise instruments.

STING-Dependent 2'-5' Oligoadenylate Synthetase-Like Production Is Required for Intracellular Mycobacterium leprae Survival.

Cytosolic detection of nucleic acids elicits a type I interferon (IFN) response and plays a critical role in host defense against intracellular pathogens. Herein, a global gene expression profile of Mycobacterium leprae-infected primary human Schwann cells identified the genes differentially expressed in the type I IFN pathway. Among them, the gene encoding 2'-5' oligoadenylate synthetase-like (OASL) underwent the greatest upregulation and was also shown to be upregulated in M. leprae-infected human macrophage cell lineages, primary monocytes, and skin lesion specimens from patients with a disseminated form of leprosy. OASL knock down was associated with decreased viability of M. leprae that was concomitant with upregulation of either antimicrobial peptide expression or autophagy levels. Downregulation of MCP-1/CCL2 release was also observed during OASL knock down. M. leprae-mediated OASL expression was dependent on cytosolic DNA sensing mediated by stimulator of IFN genes signaling. The addition of M. leprae DNA enhanced nonpathogenic Mycobacterium bovis bacillus Calmette-Guerin intracellular survival, downregulated antimicrobial peptide expression, and increased MCP-1/CCL2 secretion. Thus, our data uncover a promycobacterial role for OASL during M. leprae infection that directs the host immune response toward a niche that permits survival of the pathogen.

STING-Dependent 2'-5' oligoadenylate synthetase-like production is required for intracellular Mycobacterium leprae survival

Cytosolic detection of nucleic acids elicits a type I interferon (IFN) response and plays a critical role in host defense against intracellular pathogens. Herein, a global gene expression profile of Mycobacterium leprae-infected primary human Schwann cells identified the genes differentially expressed in the type I IFN pathway. Among them, the gene encoding 2'-5' oligoadenylate synthetase-like (OASL) underwent the greatest upregulation and was also shown to be upregulated in M. leprae-infected human macrophage cell lineages, primary monocytes, and skin lesion specimens from patients with a disseminated form of leprosy. OASL knock down was associated with decreased viability of M. leprae that was concomitant with upregulation of either antimicrobial peptide expression or autophagy levels. Downregulation of MCP-1/CCL2 release was also observed during OASL knock down. M. leprae-mediated OASL expression was dependent on cytosolic DNA sensing mediated by stimulator of IFN genes signaling. The addition of M. leprae DNA enhanced nonpathogenic Mycobacterium bovis bacillus Calmette-Guerin intracellular survival, downregulated antimicrobial peptide expression, and increased MCP-1/CCL2 secretion. Thus, our data uncover a promycobacterial role for OASL during M. leprae infection that directs the host immune response toward a niche that permits survival of the pathogen.

High Resolution Viscosity Measurement by Thermal Noise Detection.

An interferometric method is implemented in order to accurately assess the thermal fluctuations of a micro-cantilever sensor in liquid environments. The power spectrum density (PSD) of thermal fluctuations together with Sader's model of the cantilever allow for the indirect measurement of the liquid viscosity with good accuracy. The good quality of the deflection signal and the characteristic low noise of the instrument allow for the detection and corrections of drawbacks due to both the cantilever shape irregularities and the uncertainties on the position of the laser spot at the fluctuating end of the cantilever. Variation of viscosity below 0:03mPa·s was detected with the alternative to achieve measurements with a volume as low as 50 µL.

Pulling on super paramagnetic beads with micro cantilevers: single molecule mechanical assay application.

This paper demonstrates that it is possible to trap and release a super paramagnetic micro bead by fixing three super paramagnetic micro beads in a triangular array at the sensitive end of a micro cantilever, and by simply switching on/off an external magnetic field. To provide evidence of this principle we trap a micro bead that is attached to the free end of single DNA molecule and that has been previously fixed at the other end to a glass surface, using the standard sample preparation protocol of magnetic tweezers assays. The switching process is reversible which preserves the integrity of the tethered molecule, and a local force applied over the tethered bead excludes the neighbouring beads from the magnetic trap. We have developed a quadrature phase interferometer which is able to perform under fluid environments to accurately measure small deflections, which permits the exploration of DNA elasticity. Our results agree with measurements from magnetic tweezer assays performed under similar conditions. Furthermore, compared to the magnetic tweezer methodology, the combination of the magnetic trap with a suitable measurement system for cantilever deflection, allows for the exploration of a wide range of forces using a local method that has an improved temporal resolution.