Worldwide, Salmonella Typhi infections persist as an important health problem, accounting for about 9.4 million cases annually. Porins are one of the targets in the protective response against ...infection with Salmonella Typhi, a vaccine designed with these porins was shown to be safe in a phase 1 clinical trial eliciting a long-lasting response. In this work, an airlift bioreactor was designed and used to produce Salmonella Typhi biomass and purify porins. A comparison between the airlift bioreactor and shaken flasks biomass production rates was carried out considering a constant oxygen mass transfer coefficient. The analysis showed that the change in culture system does not affect the growth kinetic parameters, nor the maximum biomass production. The growth and substrate consumption kinetic parameters were estimated through mathematical models. Porins produced in the bioreactor induced equivalent humoral responses and protective capacity in mice compared to porins produced in shaken flasks. These results suggest that airlift bioreactors provide a promising platform for industrial production of porins.
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•S. Typhi porins were produced through shake flasks and airlift bioreactor cultures.•Kinetic parameters were estimated through mathematical models.•Porins produced humoral response and protective capacity in mice.
Objectives
To display a recombinant avidin fused to the autotransporter ShdA to bind biotinylated molecules on the surface of
Escherichia coli
.
Results
Two chimeric protein constructs containing ...avidin fused to the autotransporter ShdA were expressed on the surface of
Escherichia coli
DH5α. One fusion protein contained 476 amino acids of the ShdA α and β domains, whereas the second consisted of a 314 amino acid from α and truncated β domains. Protein production was verified by SDS-PAGE using an antibody to the molecular FLAG-tag. The surface display of the avidin-shdA fusion protein was confirmed by confocal microscopy and flow cytometry analysis, and the biotin-binding activity was evaluated by fluorescence microscopy and flow cytometry using biotin-4-fluorescein and biotinylated-ovalbumin (OVA).
Conclusions
Expression of a recombinant avidin with biotin-binding activity on the surface of
E. coli
was achieved using the autotransporter ShdA. This system is an alternative to bind biotinylated molecules to
E. coli.
Current medical guidelines consider pregnant women with COVID-19 to be a high-risk group. Since physiological gestation downregulates the immunological response to maintain “maternal-fetal ...tolerance”, SARS-CoV-2 infection may constitute a potentially threatening condition to both the mother and the fetus. To establish the immune profile in pregnant COVID-19+ patients, a cross-sectional study was conducted. Pregnant women with COVID-19 (P-COVID-19+; n = 15) were analyzed and compared with nonpregnant women with COVID-19 (NP-COVID-19+; n = 15) or those with physiological pregnancy (P-COVID-19-; n = 13). Serological cytokine and chemokine concentrations, leucocyte immunophenotypes, and mononuclear leucocyte responses to polyclonal stimuli were analyzed in all groups. Higher concentrations of serological TNF-α, IL-6, MIP1b and IL-4 were observed within the P-COVID-19+ group, while cytokines and chemokines secreted by peripheral leucocytes in response to LPS, IL-6 or PMA-ionomicin were similar among the groups. Immunophenotype analysis showed a lower percentage of HLA-DR+ monocytes in P-COVID-19+ than in P-COVID-19- and a higher percentage of CD39+ monocytes in P-COVID-19+ than in NP-COVID-19+. After whole blood polyclonal stimulation, similar percentages of T cells and TNF+ monocytes between groups were observed. Our results suggest that P-COVID-19+ elicits a strong inflammatory response similar to NP-COVID19+ but also displays an anti-inflammatory response that controls the ATP/adenosine balance and prevents hyperinflammatory damage in COVID-19.
SUMMARY
Entamoeba histolytica is a human pathogen that may invade the intestinal mucosa, causing amoebic colitis or hepatic abscesses when the trophozoites travel through the portal circulation to ...the liver. Lipopeptidophosphoglycan (LPPG) is a molecular pattern of E. histolytica recognized by the human immune system. Here we report that LPPG is exposed on the cell surface of E. histolytica trophozoites, and is recognized by the host through toll‐like receptor (TLR) 2 and TLR4. Correspondingly, human embryonic kidney (HEK)‐293 cells were rendered LPPG responsive through overexpression of TLR2 or TLR4/MD2. Moreover, co‐expression of CD14 enhanced LPPG signal transmission through TLR2 and TLR4. The interaction of LPPG with TLR2 and TLR4 resulted in activation of NF‐κB and release of interleukin (IL)‐10, IL‐12p40, tumour necrosis factor (TNF)‐α, and IL‐8 from human monocytes. Consistent with these findings, responsiveness of mouse macrophages lacking TLR2 expression (TLR2–/–) or functional TLR4 (TLR4d/d) to E. histolytica LPPG challenge was impaired while double deficient macrophages were unresponsive. In contrast to wild‐type control and TLR2–/–animals succumbing to lethal shock syndrome, TLR4d/dmice were resistant to systemic LPPG challenge‐induced pathology.
Simultaneous administration of certain antihypertensive (renin–angiotensin system inhibitors and diuretics) and nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with a renal toxicity ...syndrome known as “triple whammy” acute kidney injury (TW-AKI), yet poorly characterized at the pathophysiological level, as no specific experimental model exists on which to conduct preclinical research. Herein, we generated and characterized a rat model of TW-AKI (0.7 mg/kg/day trandolapril +400 mg/kg/day ibuprofen +20 mg/kg/day furosemide). Double treatments involving the NSAID caused a subclinical acute kidney injury, as they reduced glomerular filtration rate to a significant but not sufficient extent to increase Crpl concentration. Only the triple treatment generated an overt AKI with increased Crpl provided that animals were under partial water ingestion restriction. Histological examination revealed no evidence of tissue renal injury, and no proteinuria or makers of renal damage were detected in the urine. These findings, along with a normal fractional excretion of sodium and glucose, indicated that these drug combinations produce a prerenal type of AKI. In fact, blood pressure and renal blood flow were also reduced (most markedly following the triple combination), although renal dysfunction was more pronounced than expected for the corresponding pressure drop, supporting a key pathological role of the interference with renal autoregulation mechanisms. In summary, prerenal TW-AKI only occurs when volemia is challenged (i.e., by furosemide in partially water-deprived animals) under the effects of renin–angiotensin system inhibitors and NSAIDs. This model will facilitate further pathophysiological knowledge for a better diagnosis and clinical handling of this syndrome.
Combination of antihypertensive drugs with NSAID analgesics may cause a syndrome called triple whammy (TW) acute kidney injury (AKI), most often in the elderly. A rat model reveals that the TW-AKI is a prerenal form of AKI, only occurring in previously dehydrated rats, a condition particularly rife among the aged.
Summary
Inflammation is necessary for survival, but it is also an important cause of human morbidity and mortality, as exemplified by sepsis. During inflammation, cells of the innate immune system ...are recruited and activated in response to infection, trauma or injury. These cells are activated through receptors, such as Toll‐like receptors (TLRs), which recognize microbial ligands such as lipopolysaccharide (LPS). Triggering receptor expressed on myeloid cells (TREM)‐1 amplifies the inflammatory response initiated by TLRs, and its expression on the surface of monocytes increases in the presence of TLR ligands. Here we have shown that in monocytes TREM‐1 mRNA levels, measured by reverse transcription–polymerase chain reaction (RT–PCR), remained unchanged and TREM‐1 protein levels, measured by flow cytometry, increased, indicating that LPS increases TREM‐1 expression by a post‐transcriptional mechanism. We also showed that TREM‐1/Fc fusion protein decreased the ability of the sera of some patients with sepsis to activate monocytes, indicating that the TREM‐1 ligand, whose identity is unknown, may be present in the sera of some of these patients. We describe a mechanism for the regulation of TREM‐1 expression on monocytes and the possible presence of its ligand in serum; these findings help to explain the contribution of TREM‐1 during systemic inflammation.
The SARS-CoV-2 pandemic has created new scenarios that require modifications to the usual cardiopulmonary resuscitation protocols. The current clinical guidelines on the management of ...cardiorespiratory arrest do not include recommendations for situations that apply to this context. Therefore, the National Cardiopulmonary Resuscitation Plan of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC), in collaboration with the Spanish Group of Pediatric and Neonatal CPR and with the Teaching Life Support in Primary Care program of the Spanish Society of Family and Community Medicine (SEMFyC), have written these recommendations, which are divided into 5 parts that address the main aspects for each healthcare setting. This article consists of an executive summary of them.
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•Formation of black silicon solar cells was carried using out using etching methods.•MACE process using two different metals was applied to do a nanometric etching on pyramidal ...surfaces.•A double stack layer of pm-Si/SiNx was employed on the surface of the device and was treated in an ammonia plasma.•I–V measurements and EQE measurements showed better performance of the solar cell device proposed in this work.
It is well known that, in c-Si solar cells, the surface treatments are very important and have great relevance in the final efficiency of the devices. Black silicon solar cells are the terminology commonly used for solar cells with different grades of nanometric surface texturizations. In this work, we prepared silicon solar cells with a diverse grade of chemical surface treatment (alkaline etch and MACE treatment), plasma annealing (ammonia and hydrogen) with silicon-rich silicon nitride as passivation and antireflection coating. Spectral response, surface reflectance, and I–V measurements were carried out to obtain the final performance of the cell fabricated in the present work. From all the devices fabricated in the present work, the best results were obtained for the structure where the double stack layer (pm-Si/SiNx) was used as the passivation scheme, and plasma treatment was carried out in ammonia atmosphere as in comparison to existing conventional passivation schemes.
In this work, a comparative study of the physico-chemical and catalytic properties of doped and impregnated Mn-SrTiO3 for the catalytic combustion of soot has been reported. Results show that SrTiO3 ...demonstrated dendritic morphology that is attributed to SrTiO3 with perovskite structure. XPS analysis confirmed the successful incorporation of Mn4+ species in Ti4+ lattice sites for doped samples, whereas different MnOX species were formed on the surface of SrTiO3 in the case of impregnated catalysts with different Mn loadings. Among all catalysts tested in this work, samples doped with 1 wt% Mn showed the best catalytic behavior, decreasing the combustion temperature well above 100 °C compared with the uncatalyzed reaction and a Mn-turnover number of 5.77 which is comparable with previous perovskite reports. During the soot catalytic combustion process, accelerated oxidation rates were observed at high temperatures. This may be attributed to the mobility of the bulk oxygen reaching the catalyst surface, promoted by the high redox capacity of Mn-doped perovskites. Despite a reduction in the Mn species observed for MnOx impregnated samples, they showed much less catalytic activity when compared with the doped samples because of the strong contribution of bulk oxygen in the perovskite structure. These doped catalysts also displayed low catalytic activity at temperatures below 500 °C, which is possibly due to the presence of surface carbonates. This work contributes to the idea that bulk oxygen plays an important role in perovskites as a catalyst that provides enhanced catalytic activity for soot combustion.
•Dendritic impregnated and doped MnSrTiO3 were synthesized by hydrothermal method.•Different Mn and O species were detected as function of dopant or impregnated Mn.•Adsorbed species in Mn-impregnated catalyst promotes catalytic activity below 500 °C.•Doped catalyst promotes oxygen mobility at temperatures >500 °C.•Bulk oxygen plays the main role for soot combustion using perovskites as catalyst.
Gran parte de la economía de la región centro sur del estado de Chihuahua depende de la agriculcultura. Es una zona semidesértica que utiliza agua de los ríos Conchos y San Pedro para el riego de los ...cultivos. De éstos, uno de los principales es el cultivo del nogal pecanero. Sin embargo, su producción se puede ver afectada por plagas y enfermedades además de que pueden causar la muerte de los nogales. En este estudio se presenta la distribución espacial de huertas en las que se buscó la presencia de nogales muertos o muriendo, así como sus principales causales: pudrición texana (Phymatotrichum omnivorum), nematodo agallador (Meloidogyne spp), gallina ciega (Phyllophaga spp) y gusano barrenador del tronco (Euplatypus spp). El municipio que más huertas nogaleras presenta es el de Meoqui, sin embargo, es el que menor problemas de mortalidad existen, y Delicias en el que el problema es mayor, al igual que los agentes etiológicos estudiados: Phymatotrichum omnivorum, Meloidogyne spp, Phyllophaga spp y Euplatypus spp tendiendo a concentrarse en su frontera noreste.
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