From forest to savanna and back to forest: Evolutionary history of the genus Dimorphandra (Fabaceae).

The tree genus Dimorphandra (Fabaceae), which contains 26 species divided into three subgenera, was studied using DNA sequence data from six chloroplast genome regions (cpDNA) and the nuclear internal transcribed spacer (ITS). The analyses, which included Bayesian phylogenies and haplotype networks, ancestral area reconstructions, and ecological niche modeling, allowed for exploring the evolutionary history of Dimorphandra. Within the subgenus Phaneropsia, the cpDNA sequence data were more closely-related to species from the genus Mora, while the ITS sequence data displayed a closer phylogenetic relationship with the subgenus Pocillum. This incongruence may be due to incomplete lineage sorting associated with ancient polymorphisms. The Amazonian Dimophandra lineages were highly polymorphic and divergent, while those from the Cerrado and the Atlantic Forest had low levels of polymorphisms. The Amazon likely gave rise to the Dimophandra lineage that produced the Cerrado species, while a Cerrado lineage likely gave rise to the Atlantic Forest species. Habitat shifts were identified as a key factor in shaping the late evolutionary history of Dimorphandra.

Genome-wide survey and evolutionary history of the pectin methylesterase (PME) gene family in the Dothideomycetes class of fungi.

Once deposited in the plant cell wall, pectin undergoes demethylesterification by endogenous pectin methylesterases (PMEs), which play various roles in growth and development, including defense against pathogen attacks. Pathogen PMEs can alter pectin's methylesterification pattern, increasing its susceptibility to degradation by other fungal pectinases and thus playing a critical role as virulence factors during early infection stages. To investigate the evolutionary history of PMEs in the Dothideomycetes class of fungi, we obtained genomic data from 15 orders (79 species) and added genomic data from 61 isolates of Corynespora cassiicola. Our analyses involved maximum likelihood phylogenies, gene genealogies, and selection analyses. Additionally, we measured PME gene expression levels of C. cassiicola using soybean as a host through RT-qPCR assays. We recovered 145 putative effector PMEs and 57 putative non-effector PMEs from across the Dothideomycetes. The PME gene family exhibits a small size (up to 5 members per genome) and comprises three major clades. The evolutionary patterns of the PME1 and PME2 clades were largely shaped by duplications and recurring gene retention events, while biased gene loss characterized the small-sized PME3 clade. The presence of five members in the PME gene family of C. cassiicola suggests that the family may play a key role in the evolutionary success of C. cassiicola as a polyphagous plant pathogen. The haplogroups Cc_PME1.1 and Cc_PME1.2 exhibited an accelerated rate of evolution, whereas Cc_PME2.1, Cc_PME2.2, and Cc_PME2.3 seem to be under strong purifying selective constraints. All five PME genes were expressed during infection of soybean leaves, with the highest levels during from six to eight days post-inoculation. The highest relative expression level was measured for CC_29_g7533, a member of the Cc_PME2.3 clade, while the remaining four genes had relatively lower levels of expression.

Effects of Substituents on the Photophysical/Photobiological Properties of Mono-Substituted Corroles.

The trans-A2B-corrole series was prepared starting with 5-(pentafluorophenyl)dipyrromethene, which was then reacted with respective aryl-substituted aldehyde by Gryko synthesis. It was further characterized by HRMS and electrochemical methods. In addition, we investigated experimental photophysical properties (absorption, emission by steady-state and time-resolved fluorescence) in several solvents and TDDFT calculations, aggregation, photostability and reactive oxygen species generation (ROS), which are relevant when selecting photosensitizers used in photodynamic therapy and many other photo-applications. In addition, we also evaluated the biomolecule-binding properties with CT-DNA and HSA by spectroscopy, viscometry and molecular docking calculations assays.

The necrosis- and ethylene-inducing peptide 1-like protein (NLP) gene family of the plant pathogen Corynespora cassiicola.

Effectors are secreted by plant-associated microorganisms to modify the host cell physiology. As effectors, the Necrosis- and Ethylene-inducing peptide 1-like proteins (NLPs) are involded in the early phases of plant infection and may trigger host immune responses. Corynespora cassiicola is a polyphagous plant pathogen that causes target spot on many agriculturally important crops. Using genome assembly, gene prediction, and proteome annotation tools, we retrieved 135 NLP-encoding genes from proteomes of 44 isolates. We explored the evolutionary history of NLPs using Bayesian phylogeny, gene genealogies, and selection analyses. We accessed the expression profiles of the NLP genes during the early phase of C. cassiicola-soybean interaction. Three NLP putative-effector genes (Cc_NLP1.1, Cc_NLP1.2A, and Cc_NLP1.2B) were maintained in the genomes of all isolates tested. An NLP putative-non-effector gene (Cc_NLP1.3) was found in three isolates that had been originally obtained from soybean. Putative-effector NLPs were under different selective constraints: Cc_NLP1.1 was under stronger selective pressure, while Cc_NLP1.2A was under a more relaxed constraint. Meanwhile, Cc_NLP1.2B likely evolved under either positive or balancing selection. Despite highly divergent, the putative-effector NLPs maintain conserved the residues necessary to trigger plant immune responses, suggesting they are potentially functional. Only the Cc_NLP1.1 putative-effector gene was significantly expressed at the early hours of soybean colonization, while Cc_NLP1.2A and Cc_NLP1.2B showed much lower levels of gene expression.

Sublethal effects of environmental concentrations of caffeine on a neotropical freshwater fish.

Caffeine is a contaminant frequently detected in water bodies. Growth trends in both human population and caffeine consumption per capita are expected to exacerbate the occurrence of caffeine in freshwaters. Yet the effects of caffeine on native fish fauna are poorly understood. We exposed larvae of an endemic Neotropical catfish (Rhamdia quelen) to a range of caffeine concentrations for 30 days. We found that larvae exposed to the highest concentration (16 mg L-1) showed skeletal deformations and reduced growth. We further compiled measured environmental concentrations of caffeine in surface freshwater globally and performed a risk assessment. Our analysis points to a low risk to R. quelen and equally sensitive fish species in ~90% of the freshwater ecosystems considered in our analysis. The risk quotient is higher in freshwater ecosystems of South and Central America, where R. quelen is endemic. Although the ecotoxicological risk is currently low in most places, increased caffeine consumption, exacerbated by the lack of sanitation, is expected to increase caffeine concentrations in many parts of the world, posing a threat of sublethal morphological effects to local fish species.

Diagnostic Performance of Three ELISAs for Detection of Antibodies against SARS-CoV-2 in Human Samples.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that causes coronavirus disease 2019 (COVID-19) is a disease with a high rate of transmission. Serological tests are important to perform surveys and to determine the immunological status of the population. Based on this, we evaluated three enzyme-linked immunoassays (ELISAs) using different antigens from SARS-CoV-2 in a cohort of 161 patients. The performance of the ELISA developed for immunoglobulin G (IgG) measurement against SARS-CoV-2 was evaluated based on sensitivity, specificity, and accuracy. We found specificities of 0.98, 0.98, and 0.99 and sensitivities of 0.99, 0.91, and 0.87 for the nucleocapsid (N) protein, spike protein, and receptor binding domain (RBD) fraction, respectively. The accuracy assessment indicated the N protein (accuracy = 0.98) as the antigen most likely to give a correct diagnosis. Overall, the antibody responses were present for all three proteins in subjects with confirmed SARS-CoV-2 infections, showing a similar pattern of antibody production for different antigens. In summary, these highly sensitive and specific ELISAs, with a more competitive price, appear to be a valid approach for the serodiagnosis of COVID-19.

Leishmania dual-specificity tyrosine-regulated kinase 1 (DYRK1) is required for sustaining Leishmania stationary phase phenotype.

Although the multiplicative and growth-arrested states play key roles in Leishmania development, the regulators of these transitions are largely unknown. In an attempt to gain a better understanding of these processes, we characterised one member of a family of protein kinases with dual specificity, LinDYRK1, which acts as a stasis regulator in other organisms. LinDYRK1 overexpressing parasites displayed a decrease in proliferation and in cell cycle re-entry of arrested cells. Parasites lacking LinDYRK1 displayed distinct fitness phenotypes in logarithmic and stationary growth phases. In logarithmic growth phase, LinDYRK1-/- parasites proliferated better than control lines, supporting a role of this kinase in stasis, while in stationary growth phase, LinDYRK1-/- parasites had important defects as they rounded up, accumulated vacuoles and lipid bodies and displayed subtle but consistent differences in lipid composition. Moreover, they expressed less metacyclic-enriched transcripts, displayed increased sensitivity to complement lysis and a significant reduction in survival within peritoneal macrophages. The distinct LinDYRK1-/- growth phase phenotypes were mirrored by the distinct LinDYRK1 localisations in logarithmic (mainly in flagellar pocket area and endosomes) and late stationary phase (mitochondrion). Overall, this work provides first evidence for the role of a DYRK family member in sustaining promastigote stationary phase phenotype and infectivity.

Antifungal efficacy of atorvastatin-containing emulgel in the treatment of oral and vulvovaginal candidiasis.

Drug repositioning has been an important ally in the search for new antifungal drugs. Statins are drugs that act to prevent sterol synthesis in both humans and fungi and for this reason they are promissory candidates to be repositioned to treat mycoses. In this study we evaluated the antifungal activity of atorvastatin by in vitro tests to determine the minimum inhibitory concentration against azole resistant Candida albicans and its mechanisms of action. Moreover, the efficacy of both atorvastatin-loaded oral and vaginal emulgels (0.75%, 1.5% and 3% w/w) was evaluated by means of in vivo experimental models of oral and vulvovaginal candidiasis, respectively. The results showed that atorvastatin minimal inhibitory concentration against C. albicans was 31.25 µg/ml. In oral candidiasis experiments, the group treated with oral emulgel containing 3.0% atorvastatin showcased total reduction in fungal load after nine days of treatment. Intravaginal delivery atorvastatin emulgel showed considerable effectiveness at the concentration of 3% (65% of fungal burden reduction) after nine days of treatment. From these findings, it is possible to assert that atorvastatin may be promising for drug repositioning towards the treatment of these opportunistic mycoses.

Atorvastatin is a statin drug that presents antifungal activity. This study showed that atorvastatin-containing oral and vaginal emulgels were able to treat vulvovaginal and oral candidiasis of infected animal model. Therefore, we showcased that atorvastatin may be a possible therapeutic agent in order to be a used to control opportunistic mucosal fungal infections caused by Candida albicans.

Spilanthol as a promising antifungal alkylamide for the treatment of vulvovaginal candidiasis.

Spilanthol is a bioactive alkylamide from the native Amazon plant species, Acmella oleracea. However, antifungal activities of spilanthol and its application to the therapeutic treatment of candidiasis remain to be explored. This study sought to evaluate the in vitro and in vivo antifungal activity of spilanthol previously isolated from A. oleracea (spilanthol(AcO)) against Candida albicans ATCC® 10231™, a multidrug-resistant fungal strain. Microdilution methods were used to determine inhibitory and fungicidal concentrations of spilanthol(AcO). In planktonic cultures, the fungal growth kinetics, yeast cell metabolic activity, cell membrane permeability and cell wall integrity were investigated. The effect of spilanthol(AcO) on the proliferation and adhesion of fungal biofilms was evaluated by whole slide imaging and scanning electron microscopy. The biochemical composition of the biofilm matrix was also analyzed. In parallel, spilanthol(AcO) was tested in vivo in an experimental vulvovaginal candidiasis model. Our in vitro analyses in C. albicans planktonic cultures detected a significant inhibitory effect of spilanthol(AcO), which affects both yeast cell membrane and cell wall integrity, interfering with the fungus growth. C. albicans biofilm proliferation and adhesion, as well as, carbohydrates and DNA in biofilm matrix were reduced after spilanthol(AcO) treatment. Moreover, infected rats treated with spilanthol(AcO) showed consistent reduction of both fungal burden and inflammatory processes compared to the untreated animals. Altogether, our findings demonstrated that spilanthol(AcO) is an bioactive compound against planktonic and biofilm forms of a multidrug resistant C. albicans strain. Furthermore, spilanthol(AcO) can be potentially considered for therapeutical treatment of vulvovaginal candidiasis caused by C. albicans. LAY SUMMARY: This study sought to evaluate the antifungal activity of spilanthol against Candida albicans ATCC® 10 231™, a multidrug-resistant fungal strain. Our findings demonstrated that spilanthol(AcO) can be potentially considered for therapeutical treatment of vulvovaginal candidiasis caused by C. albicans.

Design, synthesis, in silico studies and in vitro evaluation of isatin-pyridine oximes hybrids as novel acetylcholinesterase reactivators.

Organophosphorus poisoning caused by some pesticides and nerve agents is a life-threating condition that must be swiftly addressed to avoid casualties. Despite the availability of medical countermeasures, the clinically available compounds lack a broad spectrum, are not effective towards all organophosphorus toxins, and have poor pharmacokinetics properties to allow them crossing the blood-brain barrier, hampering cholinesterase reactivation at the central nervous system. In this work, we designed and synthesised novel isatin derivatives, linked to a pyridinium 4-oxime moiety by an alkyl chain with improved calculated properties, and tested their reactivation potency against paraoxon- and NEMP-inhibited acetylcholinesterase in comparison to the standard antidote pralidoxime. Our results showed that these compounds displayed comparable in vitro reactivation also pointed by the in silico studies, suggesting that they are promising compounds to tackle organophosphorus poisoning.

Production of Highly Active Antiparasitic Compounds from the Controlled Halogenation of the Arrabidaea brachypoda Crude Plant Extract.

Direct halogenation of phenolic compounds present in the CH2Cl2 extract of the roots of Arrabidaea brachypoda was investigated to enhance chemodiversity. The approach is based on eco-friendly reactions using NaBr, NaI, and NaCl in aqueous media to generate multiple "unnatural" halogenated natural products from crude extracts. The halogenation reactions, monitored by UHPLC-PDA-ELSD-MS, were optimized to generate mono-, di-, or trihalogenated derivatives. To isolate these compounds, the reactions were scaled up and the halogenated analogues were isolated by semipreparative HPLC-UV and fully characterized by NMR and HR-MS data. All of the original 16 halogenated derivatives were evaluated for their antiparasitic activities against the parasites Leishmania amazonensis and Trypanosoma cruzi. Compounds presenting selective antiparasitic activities against one or both parasites with IC50 values comparable to the reference were identified.

Simvastatin Posttreatment Controls Inflammation and Improves Bacterial Clearance in Experimental Sepsis.

Sepsis is characterized by a life-threatening organ dysfunction caused by an unbalanced host response to microbe infection that can lead to death. Besides being currently the leading cause of death in intensive care units worldwide, sepsis can also induce long-term consequences among survivors, such as cognitive impairment. Statins (lipid-lowering drugs widely used to treat dyslipidemia) have been shown to possess pleiotropic anti-inflammatory and antimicrobial effects. These drugs act inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, an enzyme that catalyzes the conversion of HMG-CoA to mevalonate, the limiting step in cholesterol biosynthesis. In this work, we evaluated the therapeutic effects of simvastatin in an animal model of sepsis. In previous study from our group, statin pretreatment avoided cognitive damage and neuroinflammation in sepsis survivors. Herein, we focused on acute inflammation where sepsis was induced by cecal ligation and puncture (CLP), and the animals were treated with simvastatin (2 mg/kg) 6 h after surgery. We measured plasma biochemical markers of organ dysfunction, cell migration, cell activation, bacterial elimination, production of nitric oxide 24 h after CLP, survival rate for 7 days, and cognitive impairment 15 days after CLP. One single administration of simvastatin 6 h after CLP was able to prevent both liver and kidney dysfunction. In addition, this drug decreased cell accumulation in the peritoneum as well as the levels of TNF-α, MIF, IL-6, and IL-1ß. Simvastatin diminished the number of bacterial colony forming units (CFU) and increased the production of nitric oxide production in the peritoneum. Simvastatin treatment increased survival for the first 24 h, but it did not alter survival rate at the end of 7 days. Our results showed that posttreatment with simvastatin hampered organ dysfunction, increased local production of nitric oxide, improved bacterial clearance, and modulated inflammation in a relevant model of sepsis.

Anti-Trypanosoma cruzi effect of the photodynamic antiparasitic chemotherapy using phenothiazine derivatives as photosensitizers.

Chagas disease is endemic in Latin America and increasingly found in non-endemic countries. Its treatment is limited due to the variable efficacy and several side effects of benznidazole. Photodynamic antimicrobial chemotherapy (PACT) may be an attractive approach for treating Chagas disease. Here, the trypanocidal activity of PACT was investigated in vitro using phenothiazine derivatives. The cytotoxicity of both, methylene blue (MB) and toluidine blue (TBO), was determined on macrophages cultures using AlamarBlue method. The trypanocidal activity of the two photosensitizers was initially evaluated by determining their IC50 values against trypomastigote forms. After this, the trypanocidal effect was evaluated in cultures of infected macrophages using an automatized image analysis protocol. All experiments were performed in the dark and in the clear phase (after a photodynamic exposure). The compounds showed no cytotoxicity in both phases at the tested concentrations. The IC50 values for the sole use of MB and TBO were 2.6 and 1.2 µM, respectively. The photoactivation of the compounds using a fixed energy density (J/cm2) caused a reduction of the IC50 values to 1.0 and 0.9 µM, respectively. It was found that, on infected macrophage, the use of TBO significantly reduced the number of infected cells and parasitic load, and this effect was increased in the presence of light. The results of the present study are indicative that PACT may be considered as both selective and effective therapeutic intervention for treating Chagas disease.

Antileishmanial Activity of Dimeric Flavonoids Isolated from Arrabidaea brachypoda.

Leishmaniasis are diseases caused by parasites belonging to Leishmania genus. The treatment with pentavalent antimonials present high toxicity. Secondary line drugs, such as amphotericin B and miltefosine also have a narrow therapeutic index. Therefore, there is an urgent need to develop new drugs to treat leishmaniasis. Here, we present the in vitro anti-leishmanial activity of unusual dimeric flavonoids purified from Arrabidaea brachypoda. Three compounds were tested against Leishmana sp. Compound 2 was the most active against promastigotes. Quantifying the in vitro infected macrophages revealed that compound 2 was also the most active against intracellular amastigotes of L. amazonensis, without displaying host cell toxicity. Drug combinations presented an additive effect, suggesting the absence of interaction between amphotericin B and compound 2. Amastigotes treated with compound 2 demonstrated alterations in the Golgi and accumulation of vesicles inside the flagellar pocket. Compound 2-treated amastigotes presented a high accumulation of cytoplasmic vesicles and a myelin-like structure. When administered in L. amazonensis-infected mice, neither the oral nor the topical treatments were effective against the parasite. Based on the high in vitro activity, dimeric flavonoids can be used as a lead structure for the development of new molecules that could be useful for structure-active studies against Leishmania.

Structural and ultrastructural evaluation of the aortic wall after transplantation of bone marrow-derived cells (BMCs) in a model for atherosclerosis.

Stem cells are characterized by their ability to differentiate into multiple cell lineages and display the paracrine effect. The aim of this work was to evaluate the effect of therapy with bone marrow-derived cells (BMCs) on glucose, lipid metabolism, and aortic wall remodeling in mice through the administration of a high-fat diet and subsequent BMCs transplantation. C57BL/6 mice were fed a control diet (CO group) or an atherogenic diet (AT group). After 16 weeks, the AT group was divided into 4 subgroups: an AT 14 days group and AT 21 days group that were given an injection of vehicle and sacrificed after 14 and 21 days, respectively, and an AT-BMC 14 days group and AT-BMC 21 days group that were given an injection of BMCs and sacrificed after 14 and 21 days, respectively. The BMCs transplant had reduced blood glucose, triglycerides, and total cholesterol. There was no significant difference in relation to body mass between the transplanted groups and non-transplanted groups, and all were different than CO. There was no significant difference in the glycemic curve among AT 14 days, AT-BMC 14 days, and AT 21 days, and these were different than the CO and the AT-BMC 21 days groups. The increased thickness of the aortic wall was observed in all atherogenic groups, but was significantly smaller in group AT-BMC 21 days compared to AT 14 days and AT 21 days. Vacuoles in the media tunic, delamination and the thinning of the elastic lamellae were observed in AT 14 days and AT 21 days. The smallest number of these was displayed on the AT-BMC 14 days and AT-BMC 21 days. Marking to CD105, CD133, and CD68 were observed in AT 14 days and AT 21 days. These markings were not observed in AT-BMC 14 days or in AT-BMC 21 days. Electron micrographs show the beneficial remodeling in AT-BMC 14 days and AT-BMC 21 days, and the structural organization was similar to the CO group. Vesicles of pinocytosis, projection of smooth muscle cells, and delamination of the internal elastic lamina are seen in groups AT 14 days and AT 21 days. Endothelial cells were preserved, and regular and continuous contour in internal elastic lamelae were observed in the CO, the AT-BMC 14 days, and AT-BMC 21 days groups. In conclusion, in an atherosclerotic model using mice and atherogenic diet, the injection of BMCs improves glucose, lipid metabolism, and causes a beneficial remodeling of the aortic wall.

Midgut morphology of the predator mosquito Lutzia bigoti (Diptera: Culicidae) and its implications for feeding behavior.

Lutzia mosquitoes (Theobald, 1903) are predaceous during their larval stages, but the adult feeding is not clearly understood, especially in relation to blood feeding. In case these mosquitoes are harmless to humans and related animals, they can be useful in biological control of mosquito vectors of pathogens. Investigating the midgut morphology is a good strategy to understand the feeding behavior of this species. The midgut in Lutzia bigoti Bellardi, 1862 displays two distinct portions, a thin anterior midgut and a more dilated posterior midgut. Digestive cells form a single epithelium in the midgut. These cells have long and packed microvilli at their apex and membrane infoldings at their basal portion, the basal labyrinth. The epithelium is supported by a basal lamina. Regarding their cytoplasm, it is noteworthy the abundance of mitochondria, distributed in an apical-basal fashion, and also a whirl-shaped endoplasmic reticulum in the posterior midgut. Basal cells are also found in the midgut of L. bigoti, resembling regenerative cells. The general organization of L. bigoti's midgut closely resembles that of numerous hematophagous mosquitoes previously documented. However, it diverges due to the presence of a peritrophic matrix even when exclusively fed on sugary solutions. Peculiar aspects of L. bigoti's midgut are discussed and compared to those of other mosquito species.

Ehrlichia spp. infection worsens cardiac damage in dogs with canine visceral leishmaniasis.

In endemic areas for canine visceral leishmaniasis (CVL), the occurrence of coinfection with other pathogens, such as Ehrlichia spp., has been associated with worsening of the clinical condition. The study aimed to evaluate the occurrence of histological changes in the myocardia of dogs naturally infected with Leishmania chagasi with or without coinfection with Ehrlichia spp.. We evaluated paraffin-embedded myocardial sections from 31 dogs, affected by either L. chagasi alone or coinfected with L. chagasi and Ehrlichia spp., to compare the extent and degree of cardiac damage. The blocks were divided into two groups. G1 (dogs infected only by L. chagasi) and G2 (dogs coinfected with L. chagasi and Ehrlichia spp.). The right atrium free wall, right ventricle free wall, left ventricle, and interventricular septum of all groups were evaluated. Cardiac alterations were observed in 41.93% (52/124) of the fragments evaluated and inflammatory infiltrate was the most common pattern found. The G2 group showed a higher incidence of myocarditis, with 61.53% (32/52), compared to the G1 group, in which 20 out of 72 cases (27.7%) exhibited histopathological changes (p <0.05). These findings confirmed that coinfection can potentiate cardiac damage in dogs.

High-Content Imaging-Based Assay for SARS-CoV-2-Neutralizing Antibodies.

The COVID-19 pandemic and the consequent emergence of new SARS-CoV-2 variants of concern necessitates the determination of populational serum potency against the virus. Here, we standardized and validated an imaging-based method to quantify neutralizing antibodies against lentiviral particles expressing the spike glycoprotein (pseudovirus). This method was found to efficiently quantify viral titers based on ZsGreen-positive cells and detect changes in human serum neutralization capacity induced by vaccination with up to two doses of CoronaVac, Comirnaty, or Covishield vaccines. The imaging-based protocol was also used to quantify serum potency against pseudoviruses expressing spikes from Delta, Omicron BA.1.1.529, and BA.4/5. Our results revealed increases in serum potency after one and two doses of the vaccines evaluated and demonstrated that Delta and Omicron variants escape from antibody neutralization. The method presented herein represents a valuable tool for the screening of antibodies and small molecules capable of blocking viral entry and could be used to evaluate humoral immunity developed by different populations and for vaccine development.

A polyvalent RNA vaccine reduces the immune imprinting phenotype in mice and induces neutralizing antibodies against omicron SARS-CoV-2.

Immune imprinting is now evident in COVID-19 vaccinated people. This phenomenon may impair the development of effective neutralizing antibodies against variants of concern (VoCs), mainly Omicron and its subvariants. Consequently, the boost doses with bivalent vaccines have not shown a significant gain of function regarding the neutralization of Omicron. The approach to design COVID-19 vaccines must be revised to improve the effectiveness against VoCs. Here, we took advantage of the self-amplifying characteristic of RepRNA and developed a polyvalent formulation composed of mRNA from five VoCs. LION/RepRNA Polyvalent induced neutralizing antibodies in mice previously immunized with LION/RepRNA D614G and reduced the imprinted phenotype associated with low neutralization capacity of Omicron B.1.1.529 pseudoviruses. The polyvalent vaccine can be a strategy to handle the low neutralization of Omicron VoC, despite booster doses with either monovalent or bivalent vaccines.

DHA-rich fish oil plays a protective role against experimental cerebral malaria by controlling inflammatory and mechanical events from infection.

Every year, thousands of children, particularly those under 5 years old, die because of cerebral malaria (CM). Following conventional treatment, approximately 25% of surviving individuals have lifelong severe neurocognitive sequelae. Therefore, improved conventional therapies or effective alternative therapies that prevent the severe infection are crucial. Omega-3 (Ω-3) polyunsaturated fatty acids (PUFAs) are known to have antioxidative and anti-inflammatory effects and protect against diverse neurological disorders, including Alzheimer's and Parkinson's diseases. However, little is known regarding the effects of Ω-3 PUFAs against parasitic infections. In this study, C57BL/6 mice received supplemental treatment of a fish oil rich in the Ω-3 PUFA, docosahexaenoic acid (DHA), which was started 15 days prior to infection with Plasmodium berghei ANKA and was maintained until the end of the study. Animals treated with the highest doses of DHA, 3.0 and 6.0 g/kg body weight, had 60 and 80% chance of survival, respectively, while all nontreated mice died by the 7th day postinfection due to CM. Furthermore, the parasite load during the critical period for CM development (5th to 11th day postinfection) was controlled in treated mice. However, after this period all animals developed high levels of parasitemia until the 20th day of infection. DHA treatment also effectively reduced blood-brain barrier (BBB) damage and brain edema and completely prevented brain hemorrhage and vascular occlusion. A strong anti-inflammatory profile was observed in the brains of DHA-treated mice, as well as, an increased number of neutrophil and reduced number of CD8+ T leukocytes in the spleen. Thus, this is the first study to demonstrate that the prophylactic use of DHA-rich fish oil exerts protective effects against experimental CM, reducing the mechanical and immunological events caused by the P. berghei ANKA infection.