One-Pot Synthesis and Surfactant Removal from MCM-41 Using Microwave Irradiation.

This research pioneers the application of microwave irradiation as an innovative strategy for one-pot synthesis and surfactant elimination (cetyltrimethylammonium bromide-CTAB) from MCM-41, introducing a rapid and efficient methodology. MCM-41 silica is widely utilized in various applications due to its unique textural and structural properties. Nonetheless, the presence of residual surfactants after synthesis poses a challenge to its effective application. MCM-41 synthesis, conducted in a microwave reactor at 60 °C, provided a result within 0.5 to 1 h. Comprehensive analyses of structural, chemical, morphological, and surface characteristics were undertaken, with a focus on the impact of synthesis time on these properties. Surfactant extraction involved the use of ethanol as a solvent at 120 °C for 6 min within the microwave reactor. The acquired particles, coupled with the properties of textural and structural features, affirmed the efficacy of the synthesis process, resulting in the synthesis of MCM-41 within 36 min. This study presents the first instance of one-pot synthesis and surfactant removal from MCM-41 using a microwave reactor. The proposed method not only addresses the surfactant removal challenge, but also substantially accelerates the synthesis process, thereby enhancing the potential for MCM-41's application in diverse fields.

Fast, low-cost and highly specific colorimetric RT-LAMP assays for inference of SARS-CoV-2 Omicron BA.1 and BA.2 lineages.

Two lineages (BA.1 and BA.2) of the Omicron variant are the main ones responsible for the recent COVID-19 pandemic waves worldwide. Monitoring the prevalence and spread of these variants is important as the presence of mutations might lower the efficacy of vaccines and hinder the benefits of monoclonal antibody therapies. Although the need to screen these new lineages is emerging, genetic sequencing is scarce due to its high cost. Alternatively, we propose using reverse transcription loop-mediated isothermal amplification (RT-LAMP) to infer the prevalence of these lineages and aid in genomic surveillance in countries with limited genetic sequencing capacity. For this, we designed specific primers and tested them on a panel of 267 sequenced RNA genomes from different lineages. The test for BA.1 and its descendants showed 96.63% sensitivity, 100% specificity, and 98.85% accuracy, and the test for BA.2 and descendants showed 90.00% sensitivity, 98.85% specificity, and 98.52% accuracy. These results demonstrate the potential of RT-LAMP to be an alternative to help monitor variants, especially in countries with scarce resources.

The Chemokine CCL5 Inhibits the Replication of Influenza A Virus Through SAMHD1 Modulation.

Influenza A virus (IAV) is the main etiological agent of acute respiratory tract infections. During IAV infection, interferon triggers the overexpression of restriction factors (RFs), the intracellular antiviral branch of the innate immune system. Conversely, severe influenza is associated with an unbalanced pro-inflammatory cytokine release. It is unclear whether other cytokines and chemokines released during IAV infection modulate RFs to control virus replication. Among the molecules enhanced in the infected respiratory tract, ligands of the CCR5 receptor play a key role, as they stimulate the migration of inflammatory cells to the alveoli. We investigated here whether ligands of the CCR5 receptor could enhance RFs to levels able to inhibit IAV replication. For this purpose, the human alveolar basal epithelial cell line (A549) was treated with endogenous (CCL3, CCL4 and CCL5) or exogenous (HIV-1 gp120) ligands prior to IAV infection. The three CC-chemokines tested reduced infectious titers between 30% to 45% upon 24 hours of infection. Eploying RT-PCR, a panel of RF mRNA levels from cells treated with CCR5 agonists was evaluated, which showed that the SAMHD1 expression was up-regulated four times over control upon exposure to CCL3, CCL4 and CCL5. We also found that IAV inhibition by CCL5 was dependent on PKC and that SAMHD1 protein levels were also increased after treatment with CCL5. In functional assays, we observed that the knockdown of SAMHD1 resulted in enhanced IAV replication in A549 cells and abolished both CCL5-mediated inhibition of IAV replication and CCL5-mediated cell death inhibition. Our data show that stimuli unrelated to interferon may trigger the upregulation of SAMHD1 and that this RF may directly interfere with IAV replication in alveolar epithelial cells.

Severe Acute Respiratory Syndrome Coronavirus 2 P.2 Lineage Associated with Reinfection Case, Brazil, June-October 2020.

A 37-year-old healthcare worker from the northeastern region of Brazil experienced 2 clinical episodes of coronavirus disease. Infection with severe acute respiratory syndrome coronavirus 2 was confirmed by reverse transcription PCR in samples collected 116 days apart. Whole-genome sequencing revealed that the 2 infections were caused by the most prevalent lineage in Brazil, B.1.1.33, and the emerging lineage P.2. The first infection occurred in June 2020; Bayesian analysis suggests reinfection at some point during September 14-October 11, 2020, a few days before the second episode of coronavirus disease. Of note, P.2 corresponds to an emergent viral lineage in Brazil that contains the mutation E484K in the spike protein. The P.2 lineage was initially detected in the state of Rio de Janeiro, and since then it has been found throughout the country. Our findings suggest not only a reinfection case but also geographic dissemination of the emerging Brazil clade P.2.

Inibição da replicação do influenza através da modulação de fatores restritivos pelos ligantes dos receptores CCR5 e CXCR4 / Inhibition of influenza replication through modulation of restrictive factors by CCR5 and CXCR4 receptor ligands

Dados da Organização Mundial da Saúde (OMS) mostram que a gripe é uma doença que afeta com gravidade de 3 a 5 milhões de pessoas em todo o mundo promovendo, anualmente, de 290 a 650 mil mortes. A gravidade da doença pode ser ainda maior quando surgem cepas pandêmicas, para as quais a população tem pouca ou nenhuma imunidade. Portanto, os vírus influenza são considerados os principais agentes virais causadores de infecções respiratórias agudas e tem grande importância epidemiológica. Durante a infecção por influenza, o interferon liberado na resposta imune inata induz cascatas de sinalizações intracelulares, levando a expressão de diferentes genes. Muitos desses genes codificam proteínas nas células, incluindo os fatores de restrição (FRs). É largamente descrito na literatura que os FRs presentes nas células do hospedeiro são proteínas antivirais, que atuam sobre a replicação de diversos vírus, prejudicando o ciclo infeccioso desses patógenos. Nosso grupo já observou que uma proteína do HIV-1, gp120, é capaz de inibir a replicação do vírus influenza A(H1N1)pdm09. Sendo assim, visamos investigar se ligantes dos receptores CCR5 (R5) e CXCR4 (X4) poderiam modular fatores restritivos de forma a inibir a replicação do vírus influenza. Para isso, células A549 foram expostas aos ligantes endógenos dos receptores R5 e X4, CCL3, CCL4, CCL5, CXCL12 ou exógenos, gp120 R5-trópicos e gp120 X4-trópicos. Então, as células foram infectadas com o vírus A/H3N2 com MOI 2 por 1h. Após 24 h, o título viral foi avaliado por RT-PCR em tempo real. A monocamada celular foi exposta aos ligantes de R5 e lisada para avaliação dos níveis de RNAm de diferentes FRs, utilizando um painel. Em seguida, as células A549 foram expostas aos ligantes de R5 e lisadas para a quantificação do nível proteico do FR SAMHD1 por immunoblotting

Realizamos também um ensaio funcional no qual células A549 sofreram knockdown para SAMHD1 e foram infectadas com o A/H3N2. Adicionalmente, as células foram tratadas com guanosina para avaliar o papel regulatório de dNTPs por SAMHD1. Nossos resultados mostraram que a exposição aos ligantes endógenos e exogenos inibiram a replicação do vírus influenza em torno de 50%, em células A549. Através do painel de RNAm para FRs, observamos aumento de 4X dos transcritos para o FR SAMHD1. Observamos também que os ligantes de R5 aumentaram o conteúdo proteico de SAMHD1 em até 3X. Com o experimento funcional de knockdown, observamos que a diminuição dos níveis proteicos de SAMHD1 leva ao aumento da replicação viral, no modelo utilizado. O tratamento com guanosina em células expostas aos ligantes de R5 inibiu ainda mais a replicação do vírus influenza, sugerindo que o mecanismo inibitório possa ser mediado pela ativação da atividade de desoxinucleotídeo trifosfohidrolase de SAMHD1. Sendo assim, nossos dados mostram pela primeira vez uma relação direta de SAMHD1 com inibição da replicação do influenza, além disso, traz perspectivas para novos estudos sobre a modulação de sinalizações, através de receptores celulares, para induzir proteínas de grande importância no controle de infecções virais relevantes para a saúde pública. (AU)

Inhibitory effect of microalgae and cyanobacteria extracts on influenza virus replication and neuraminidase activity.

BACKGROUND: The influenza virus can cause seasonal infections with mild to severe symptoms, circulating worldwide, and it can affect people in any age group. Therefore, this infection is a serious public health problem that causes severe illness and death in high-risk populations. Every year, 0.5% of the world's population is infected by this pathogen. This percentage can increase up to ten times during pandemics. Influenza vaccination is the most effective way to prevent disease. In addition, anti-influenza drugs are essential for prophylactic and therapeutic interventions. The oseltamivir (OST, a neuraminidase inhibitor) is the primary antiviral used in clinics during outbreaks. However, OST resistant viruses may emerge naturally or due to antiviral pressure, with a prevalence of 1-2% worldwide. Thus, the search for new anti-influenza drugs is extremely important. Currently, several groups have been developing studies describing the biotechnological potential of microalgae and cyanobacteria, including antiviral activity of their extracts. In Brazil, this potential is poorly known and explored. METHODS: With the aim of increasing the knowledge on this topic, 38 extracts from microalgae and cyanobacteria isolated from marine and freshwater biomes in Brazil were tested against: cellular toxicity; OST-sensitive and resistant influenza replications; and neuraminidase activity. RESULTS: For this purpose, Madin-Darby Canine Kidney (MDCK)-infected cells were treated with 200 µg/mL of each extract. A total of 17 extracts (45%) inhibited influenza A replication, with seven of them resulting in more than 80% inhibition. Moreover, functional assays performed with viral neuraminidase revealed two extracts (from Leptolyngbya sp. and Chlorellaceae) with IC50 mean < 210 µg/mL for influenza A and B, and also OST-sensitive and resistant strains. Furthermore, MDCK cells exposed to 1 mg/mL of all the extracts showed viability higher than 80%. DISCUSSION: Our results suggest that extracts of microalgae and cyanobacteria have promising anti-influenza properties. Further chemical investigation should be conducted to isolate the active compounds for the development of new anti-influenza drugs. The data generated contribute to the knowledge of the biotechnological potential of Brazilian biomes that are still little explored for this purpose.

One new species and two redescriptions of Marphysa (Eunicidae, Annelida) species of the Aenea-group from Australia.

Species of Marphysa belonging to the Aenea-group have compound falcigers as the subacicular chaetae along the entire body. Around 30 species belong to this group, among these, two have originally been described based on Australian specimens, M. bifurcata and M. sessilobranchiata. Here, we redescribe both species based on type and non-type material and describe a species new to science, M. pseudosessiloa n. sp., including intraspecific variation. Informative features for the identification of these species are relative length of prostomial appendages in relation to prostomium, shape of notopodial cirri, left MxIV plate, left and right MxIV attachment lamellae and placement of branchial stem. A taxonomic key to species of Marphysa currently reported from Australia is also provided.