Immune Reactions of Vector Insects to Parasites and Pathogens.

This overview initially describes insect immune reactions and then brings together present knowledge of the interactions of vector insects with their invading parasites and pathogens. It is a way of introducing this Special Issue with subsequent papers presenting the latest details of these interactions in each particular group of vectors. Hopefully, this paper will fill a void in the literature since brief descriptions of vector immunity have now been brought together in one publication and could form a starting point for those interested and new to this important area. Descriptions are given on the immune reactions of mosquitoes, blackflies, sandflies, tsetse flies, lice, fleas and triatomine bugs. Cellular and humoral defences are described separately but emphasis is made on the co-operation of these processes in the completed immune response. The paper also emphasises the need for great care in extracting haemocytes for subsequent study as appreciation of their fragile nature is often overlooked with the non-sterile media, smearing techniques and excessive centrifugation sometimes used. The potential vital role of eicosanoids in the instigation of many of the immune reactions described is also discussed. Finally, the priming of the immune system, mainly in mosquitoes, is considered and one possible mechanism is presented.

Antiviral activity of terpenes isolated from marine brown seaweeds against herpes simplex virus type 2.

Herpes simplex virus type 2 (HSV-2) is the most common agent of sexually transmitted infections around the world. Currently, no vaccine is available, and acyclovir is the reference compound in treatment HSV-2 infections. However, the emergence of resistant strains has reduced the efficacy in treatment. Several studies have shown marine seaweed biological activities, but there are no studies yet about the activity anti-HSV-2 of two its secundary metabolites, atomaric acid (1) and marine dolastane (2), isolated from Stypopodium zonale and Canistrocarpus cervicornis respectively. Therefore, we evaluated the anti-HSV-2 activity of compounds 1 and 2. Both compounds showed anti-HSV-2 activity with low cytotoxicity and compound 1 inactivated 90% of the viral particles at 50 µM. Both compounds inhibited the penetration and results in silico indicated the compound 1 as possible therapy alternative anti -HSV-2.

Ethyl acetate fractions of Myrciaria floribunda, Ocotea pulchella, and Ocotea notata exhibit promising in vitro activity against Sporothrix brasiliensis isolates with low susceptibility to itraconazole.

Sporothrix brasiliensis with low susceptibility isolates were described from the Brazilian zoonotic sporotrichosis hyperendemics. The aim of this work was to evaluate distinct fractions of Ocotea pulchella, Ocotea notata, Myrciaria floribunda, and Hypericum brasiliense plant extracts against itraconazole-sensitive and low susceptibility S. brasiliensis isolates. Crude extracts were tested against clinical isolates and the ATCC MYA4823 to determine the minimum inhibitory concentrations (MICs) and fungicidal or fungistatic activities (MFC). A high MICs and MFCs amplitude (1 - > 128 µg/mL) were obtained for seven extracts. The highest antimicrobial activities against sensitive S. brasiliensis were displayed by the ethyl acetate extracts of O. notata (MIC = 2-128 µg/mL) and M. floribunda (MIC = 1-8 µg/mL). A fungicidal effect was observed for all fraction extracts. Ocotea spp. and M. floribunda ethyl acetate extracts provide promising profiles against itraconazole-sensitive or low susceptibility S. brasiliensis. Future studies will determine if these extracts can contribute as alternative therapies to this neglected zoonosis.

Chloroquinolone Carboxamide Derivatives as New Anti-HSV-1 Promising Drugs.

BACKGROUND: Since the emergence of HSV resistant strains, new antiviral agents have emerged and still are urgently needed, especially those with alternative targets. OBJECTIVE: In this work, we evaluated new quinolone derivatives as anti-HSV. METHODS: For this study, cells were infected and treated with different components to evaluate the profile of HSV replication in vitro. In addition, studies were performed to determine the pharmacokinetic toxicity and profile of the compound. RESULTS: Indeed the EC50 values of these promising molecules ranged between 8 µM and 32 µM. We have also showed that all compounds inhibited the expression of ICP27 viral proteins, which gives new insights in the search for new target for antiherpetic therapy. Chlorine in positions C6 and phosphonate in position C1 have shown to be important for viral inhibition. The chloroquinolone carboxamide derivatives fulfilled "Lipinsky Rule of Five" for good oral bioavailability and showed higher intestinal absorption and blood brain barrier penetration, as well as lower toxicity profile. CONCLUSION: Although the inhibition activities of chloroquinolone carboxamide derivatives were lower than acyclovir, they showed different modes of action in comparison to the drugs currently available. These findings encourage us to continue pre-clinical studies for the development of new anti-HSV-1 agents.

Reaching the Final Endgame for Constant Waves of COVID-19.

Despite intramuscular vaccines saving millions of lives, constant devastating waves of SARS-CoV-2 infections continue. The elimination of COVID-19 is challenging, but necessary in order to avoid millions more people who would suffer from long COVID if we fail. Our paper describes rapidly advancing and innovative therapeutic strategies for the early stage of infection with COVID-19 so that tolerating continuing cycles of infection should be unnecessary in the future. These therapies include new vaccines with broader specificities, nasal therapies and antiviral drugs some targeting COVID-19 at the first stage of infection and preventing the virus entering the body in the first place. Our article describes the advantages and disadvantages of each of these therapeutic options which in various combinations could eventually prevent renewed waves of infection. Finally, important consideration is given to political, social and economic barriers that since 2020 hindered vaccine application and are likely to interfere again with any COVID-19 endgame.

Covid-19, síndromes respiratórias e a fisioterapia: relações essenciais a serem compreendidas / Covid-19, respiratory syndromes and physical therapy: essential relations to be understood

Introdução: A pandemia por SARS-CoV-2 destacou o trabalho dos fisioterapeutas, sobretudo em relação à assistência aos pacientes acometidos pela Síndrome Respiratória Aguda Grave, também conhecida como Coronavirus Disease 2019 (COVID-19). Objetivo: O presente estudo visou destacar a importância do trabalho dos fisioterapeutas no cuidado aos pacientes com COVID-19. Métodos: Trata-se de uma revisão de literatura que utilizou as bases de dados da Biblioteca Virtual em Saúde (BVS), Portal de Periódicos da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) e do Medline/Pubmed e seguintes descritores: COVID-19 and Respiratory Syndrome and Physical therapy. Os critérios de inclusão foram os estudos publicados de dezembro de 2019 a setembro de 2020, nos idiomas inglês, espanhol e francês, disponíveis online, na íntegra e com abordagem plena do conteúdo. Resultados: Foram encontrados 160 artigos, dos quais 32 foram selecionados a partir dos critérios de inclusão. Conclusão: Os estudos relataram melhora clínica e funcional a partir das intervenções fisioterapêuticas aplicadas aos pacientes, sendo as medidas com maior impacto positivo na mobilização precoce, aspirações de secreções, monitoramento da ventilação mecânica e reabilitação. É de suma importância o fisioterapeuta estar inserido na equipe multidisciplinar que compõe o ambiente hospitalar.

The perceptions of Brazilian postgraduate students about the impact of COVID-19 on their well-being and academic performance.

This study aimed at identifying the perceptions of Brazilian postgraduate students from all over the country on the impacts of the COVID-19 pandemic on their academic trajectories. Data from 5985 postgraduate students were collected in the end of 2020, through a 37-item questionnaire, including multiple-choice questions, through Google Forms. The questions were divided into blocks with different proposals: personal profile, academic profile, issues related to COVID-19 infection, and issues related to mental health. Our analysis showed that 51.43% were master's degree students; 43.02% were doctorate and 5.55% were specialization students, mostly attending Biological, Health, and Human Sciences post-graduation courses (18.13%, 17.91%, and 17.38%, respectively) of different Brazilian educational institutions, including public (e.g., UFRJ) and private (e.g., PUC) federal universities as well as research institutions (e.g., Fiocruz) from all five regions of Brazil (north, south, southeast, northeast, and center Midwest). Most of them were academically impacted by the COVID-19 pandemic, which also involved psychological aspects such as high levels of anxiety and depression. The results showed readjustments of research projects, and academic activities, which in some particular research fields led to the successful completion through the remote activities. However, efforts are still needed by graduate programs in order to allow greater flexibility in academic activities to fulfill all previous planning and chronograms, in addition to implementing ongoing projects to support students' mental health.

Study on the synthesis and structure-activity relationship of 1,2,3-triazoles against toxic activities of Bothrops jararaca venom.

Snakebite envenoming is a health concern and has been a neglected tropical disease since 2017, according to the World Health Organization. In this study, we evaluated the ability of ten 1,2,3-triazole derivatives AM001 to AM010 to inhibit pertinent in vitro (coagulant, hemolytic, and proteolytic) and in vivo (hemorrhagic, edematogenic, and lethal) activities of Bothrops jararaca venom. The derivatives were synthesized, and had their molecular structures fully characterized by CHN element analysis, Fourier-transform infrared spectroscopy and Nuclear magnetic resonance. The derivatives were incubated with the B. jararaca venom (incubation protocol) or administered before (prevention protocol) or after (treatment protocol) the injection of B. jararaca venom into the animals. Briefly, the derivatives were able to inhibit the main toxic effects triggered by B. jararaca venom, though with varying efficacies, and they were devoid of toxicity through in vivo, in silico or in vitro analyses. However, it seemed that the derivatives AM006 or AM010 inhibited more efficiently hemorrhage or lethality, respectively. The derivatives were nontoxic. Therefore, the 1,2,3-triazole derivatives may be useful as an adjuvant to more efficiently treat the local toxic effects caused by B. jararaca envenoming.

Overview of paratransgenesis as a strategy to control pathogen transmission by insect vectors.

This article presents an overview of paratransgenesis as a strategy to control pathogen transmission by insect vectors. It first briefly summarises some of the disease-causing pathogens vectored by insects and emphasises the need for innovative control methods to counter the threat of resistance by both the vector insect to pesticides and the pathogens to therapeutic drugs. Subsequently, the state of art of paratransgenesis is described, which is a particularly ingenious method currently under development in many important vector insects that could provide an additional powerful tool for use in integrated pest control programmes. The requirements and recent advances of the paratransgenesis technique are detailed and an overview is given of the microorganisms selected for genetic modification, the effector molecules to be expressed and the environmental spread of the transgenic bacteria into wild insect populations. The results of experimental models of paratransgenesis developed with triatomines, mosquitoes, sandflies and tsetse flies are analysed. Finally, the regulatory and safety rules to be satisfied for the successful environmental release of the genetically engineered organisms produced in paratransgenesis are considered.

Molecular modelling and dynamics simulations of single-wall carbon nanotube as a drug carrier: New insights into the drug-loading process.

Cancer remains among the world's top devastating diseases, with millions of lives been affected each year. Conventional anticancer therapies are often far from ideal due to non-selective biodistribution. Therefore, the carbon nanotube (CNT) has been developed as a drug carrier for targeting specific cancer cells. In this work, we applied computer modeling approaches to investigate the interactions of single-wall carbon nanotube (SWCNT) with three different anticancer drugs: doxorubicin (DOX), Bendamustine (BEN), and Carmustine (CAR). Here we find physicochemical characteristics from the ligands that can contribute to a higher affinity towards the CNT, such as the presence of halogen substituents and the positively charged cation. On the other hand, the presence of anions groups, such as carboxylate, can decrease the interaction of the ligands and CNT. The binding free energy results indicate the SWCNT(15,15) with a diameter of 20.3 Å as the most favorable for encapsulating drugs ranging from 12 to 39 heavy atoms. The basic knowledge obtained from this study is expected to contribute to the molecular understanding of drug-loaded SWCNT for the development of a more efficiently anticancer drug carrier.

Synthetic Derivatives against Wild-Type and Non-Wild-Type Sporothrix brasiliensis: In Vitro and In Silico Analyses.

Recently, the well-known geographically wide distribution of sporotrichosis in Brazil, combined with the difficulties of effective domestic feline treatment, has emphasized the pressing need for new therapeutic alternatives. This work considers a range of synthetic derivatives as potential antifungals against Sporothrix brasiliensis isolated from cats from the hyperendemic Brazilian region. Six S. brasiliensis isolates from the sporotrichotic lesions of itraconazole responsive or non-responsive domestic cats were studied. The minimum inhibitory concentrations (MICs) of three novel hydrazone derivatives and eleven novel quinone derivatives were determined using the broth microdilution method (M38-A2). In silico tests were also used to predict the pharmacological profile and toxicity parameters of these synthetic derivatives. MICs and MFCs ranged from 1 to >128 µg/mL. The ADMET computational analysis failed to detect toxicity while a good pharmacological predictive profile, with parameters similar to itraconazole, was obtained. Three hydrazone derivatives were particularly promising candidates as antifungal agents against itraconazole-resistant S. brasiliensis from the Brazilian hyperendemic region. Since sporotrichosis is a neglected zoonosis currently spreading in Latin America, particularly in Brazil, the present data can contribute to its future control by alternative antifungal drug design against S. brasiliensis, the most virulent and prevalent species of the hyperendemic context.

Perceptions and Feelings of Brazilian Health Care Professionals Regarding the Effects of COVID-19: Cross-sectional Web-Based Survey.

BACKGROUND: The importance of health professionals has been recognized in COVID-19 pandemic-affected countries, especially in those such as Brazil, which is one of the top 3 countries that have been affected in the world. However, the workers' perception of the stress and the changes that the pandemic has caused in their lives vary according to the conditions offered by these affected countries, including salaries, individual protection equipment, and psychological support. OBJECTIVE: The purpose of this study was to identify the perceptions of Brazilian health workers regarding the COVID-19 pandemic impact on their lives, including possible self-contamination and mental health. METHODS: This cross-sectional web-based survey was conducted in Brazil by applying a 32-item questionnaire, including multiple-choice questions by using the Google Forms electronic assessment. This study was designed to capture spontaneous perceptions from health professionals. All questions were mandatory and divided into 2 blocks with different proposals: personal profile and COVID-19 pandemic impact. RESULTS: We interviewed Brazilian health professionals from all 5 Brazilian regions (N=1376). Our study revealed that 1 in 5 (23%) complained about inadequate personal protective equipment, including face shields (234/1376, 17.0%), masks (206/1376, 14.9%), and laboratory coats (138/1376, 10.0%), whereas 1 in 4 health professionals did not have enough information to protect themselves from the coronavirus disease. These professionals had anxiety due to COVID-19 (604/1376, 43.9%), difficulties in sleep (593/1376, 43.1%), and concentrating on work (453/1376, 32.9%). Almost one-third experienced traumatic situations at work (385/1376, 28.0%), which may have led to negative feelings of fear of COVID-19 and sadness. Despite this situation, there was hope and empathy among their positive feelings. The survey also showed that 1 in 5 acquired COVID-19 with the most classic and minor symptoms, including headache (274/315, 87.0%), body pain (231/315, 73.3%), tiredness (228/315, 72.4%), and loss of taste and smell (208/315, 66.0%). Some of their negative feelings were higher than those of noninfected professionals (fear of COVID-19, 243/315, 77.1% vs 509/1061, 48.0%; impotence, 142/315, 45.1% vs 297/1061, 28.0%; and fault, 38/315, 12.1% vs 567/1061, 53.4%, respectively). Another worrying outcome was that 61.3% (193/315) reported acquiring an infection while working at a health facility and as expected, most of the respondents felt affected (344/1376, 25.0%) or very affected (619/1376, 45.0%) by the COVID-19. CONCLUSIONS: In Brazil, the health professionals were exposed to a stressful situation and to the risk of self-contamination-conditions that can spell future psychological problems for these workers. Our survey findings showed that the psychological support for this group should be included in the future health planning of Brazil and of other hugely affected countries to assure a good mental health condition for the medical teams in the near future.

Biotechnological Potential of Streptomyces Siderophores as New Antibiotics.

BACKGROUND: Siderophores are small-molecule iron-chelators produced by microorganisms and plants growing mostly under low iron conditions. Siderophores allow iron capture and transport through cell membranes into the cytoplasm, where iron is released for use in biological processes. These bacterial iron uptake systems can be used for antibiotic conjugation or as targets for killing pathogenic bacteria. Siderophores have been explored recently because of their potential applications in environmental and therapeutic research. They are present in Streptomyces, Grampositive bacteria that are an important source for discovering new siderophores. OBJECTIVE: This review summarizes siderophore molecules produced by the genus Streptomyces emphasizing their potential as biotechnological producers and also illustrating genomic tools for discovering siderophores useful for treating bacterial infections. METHODS: The literature search was performed using PUBMED and MEDLINE databases with keywords siderophore, secondary metabolites, Trojan horse strategy, sideromycin and Streptomyces. The literature research focused on bibliographic databases including all siderophores identified in the genus Streptomyces. In addition, reference genomes of Streptomyces from GenBank were used to identify siderophore biosynthetic gene clusters by using the antiSMASH platform. RESULTS: This review has highlighted some of the many siderophore molecules produced by Streptomyces, illustrating the diversity of their chemical structures and a wide spectrum of bioactivities against pathogenic bacteria. Furthermore, the possibility of using siderophores conjugated with antibiotics could be an alternative to overcome bacterial resistance to drugs and could improve their therapeutic efficacy. CONCLUSION: This review confirms the importance of Streptomyces as a rich source of siderophores, and underlines their potential as antibacterial agents.

Antibiofilm effects of N,O-acetals derived from 2-amino-1,4-naphthoquinone are associated with downregulation of important global virulence regulators in methicillin-resistant Staphylococcus aureus.

Despite the existing antibiotics, antimicrobial resistance is a major challenge. Consequently, the development of new drugs remains in great demand. Quinones is part of a broad group of molecules that present antibacterial activity besides other biological properties. The main purpose of this study was to evaluate the antibiofilm activities of synthetic N,O-acetals derived from 2-amino-1,4-naphthoquinone [7a: 2-(methoxymethyl)-amino-1,4-naphthoquinone; 7b: 2-(ethoxymethyl)-amino-1,4-naphthoquinone; and 7c: 2-(propynyloxymethyl)-amino-1,4-naphthoquinone] against methicillin-resistant Staphylococcus aureus (MRSA). The derivatives 7b and 7c, specially 7b, caused strong impact on biofilm accumulation. This inhibition was linked to decreased expression of the genes fnbA, spa, hla and psmα3. More importantly, this downregulation was paralleled by the modulation of global virulence regulators. The substitution of 2-ethoxymethyl (7b) in comparison with 2-propynyloxymethyl (7c) enhanced sarA-agr inhibition, decreased fnbA transcripts (positively regulated by sarA) and strongly impaired biofilm accumulation. Indeed, 7b triggered intensive autolysis and was able to eliminate vancomycin-persistent cells. Consequently, 7b is a promising molecule displaying not only antimicrobial effects, but also antibiofilm and antipersistence activities. Therefore, 7b is a good candidate for further studies involving the development of novel and more rational antimicrobials able to act in chronic and recalcitrant infections, associated with biofilm formation.

First report of meticillin-resistant Staphylococcus aureus harboring mecC gene in milk samples from cows with mastitis in southeastern Brazil.

MRSA infection and colonization have been reported in both companion and food-chain animals, highlighting MRSA as an important veterinary and zoonotic pathogen. Another mec allele, the mecC gene, also confers beta-lactam resistance in Staphylococcus aureus and shows 69% nucleotide identity to mecA. The main aim of this study was to investigate the genotypic and clonal profile of methicillin-resistant S. aureus (MRSA) from cows with mastitis in dairy herds. Thirty-five samples suggestive of bovine subclinical mastitis were evaluated, and S. aureus were detected in all of them using both phenotypic and molecular approaches. According to the multilocus sequence typing (MLST), the S. aureus isolates were assigned in five different STs, 21 (60%) showed ST 742, 6 (17%) ST97, 4 (11%) ST1, 2 (6%) ST30, and 2 (6%) ST126. The presence of mecA was not observed in any of these isolates whereas mecC was detected in nine of them (9/35; 26%). The Panton-Valentine leukocidin (PVL) genes were detected in a total of 4 isolates. Among the 35 isolates analyzed, 26 showed resistance to penicillin. Changes in the S. aureus epidemiology due to the detection of MRSA in milk samples from cows presenting with bovine subclinical mastitis may have consequences for public health in Brazil, challenging the empirical therapy and animal management, with potential medical and social outcomes. To the best of our knowledge, this is the first report describing mecC MRSA in Southeastern Brazil.

Design, synthesis, in vitro and in silico studies of novel 4-oxoquinoline ribonucleoside derivatives as HIV-1 reverse transcriptase inhibitors.

Human immunodeficiency virus type 1 (HIV-1) is a public health problem that affects over 38 million people worldwide. Although there are highly active antiretroviral therapies, emergence of antiviral resistant strains is a problem which leads to almost a million death annually. Thus, the development of new drugs is necessary. The viral enzyme reverse transcriptase (RT) represents a validated therapeutic target. Because the oxoquinolinic scaffold has substantial biological activities, including antiretroviral, a new series of 4-oxoquinoline ribonucleoside derivatives obtained by molecular hybridization were studied here. All synthesized compounds were tested against human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT), and 9a and 9d displayed the highest antiviral activities, with IC50 values of 1.4 and 1.6 µM, respectively. These compounds were less cytotoxic than AZT and showed CC50 values of 1486 and 1394 µM, respectively. Molecular docking studies showed that the most active compounds bound to the allosteric site of the enzyme, suggesting a low susceptibility to the development of antiviral resistance. In silico pharmacokinetic and toxicological evaluations reinforced the potential of the active compounds as anti-HIV candidates for further exploration. Overall, this work showed that compounds 9a and 9d are promising scaffold for future anti-HIV-1 RT drug design.

Synthesis, In Vitro and In Silico Studies of Indolequinone Derivatives against Clinically Relevant Bacterial Pathogens.

BACKGROUND: According to the World Health Organization, antimicrobial resistance is one of the most important public health threats of the 21st century. Therefore, there is an urgent need for the development of antimicrobial agents with new mechanism of action, especially those capable of evading known resistance mechanisms. OBJECTIVE: We described the synthesis, in vitro antimicrobial evaluation, and in silico analysis of a series of 1H-indole-4,7-dione derivatives. METHODS: The new series of 1H-indole-4,7-diones was prepared with good yield by using a copper(II)- mediated reaction between bromoquinone and ß-enamino ketones bearing alkyl or phenyl groups attached to the nitrogen atom. The antimicrobial potential of indole derivatives was assessed. Molecular docking studies were also performed using AutoDock 4.2 for Windows. Characterization of all compounds was confirmed by one- and two-dimensional NMR techniques 1H and 13C NMR spectra [1H, 13C - APT, 1H x 1H - COSY, HSQC and HMBC], IR and mass spectrometry analysis. RESULTS: Several indolequinone compounds showed effective antimicrobial profile against Grampositive (MIC = 16 µg.mL-1) and Gram-negative bacteria (MIC = 8 µg.mL-1) similar to antimicrobials current on the market. The 3-acetyl-1-(2,5-dimethylphenyl)-1H-indole-4,7-dione derivative exhibited an important effect against different biofilm stages formed by a serious hospital life-threatening resistant strain of Methicillin-Resistant Staphylococcus aureus (MRSA). A hemocompatibility profile analysis based on in vitro hemolysis assays revealed the low toxicity effects of this new series. Indeed, in silico studies showed a good pharmacokinetics and toxicological profiles for all indolequinone derivatives, reinforcing their feasibility to display a promising oral bioavailability. An elucidation of the promising indolequinone derivatives binding mode was achieved, showing interactions with important sites to biological activity of S. aureus DNA gyrase. These results highlighted 3-acetyl-1-(2-hydroxyethyl)-1Hindole- 4,7-dione derivative as broad-spectrum antimicrobial prototype to be further explored for treating bacterial infections. CONCLUSION: The highly substituted indolequinones were obtained in moderate to good yields. The pharmacological study indicated that these compounds should be exploited in the search for a leading substance in a project aimed at obtaining new antimicrobials effective against Gram-negative bacteria.