Dengue virus (DENV) and chikungunya virus (CHIKV) are reemergent arboviruses that are transmitted by mosquitoes of the Aedes genus. During the last several decades, these viruses have been ...responsible for millions of cases of infection and thousands of deaths worldwide. Therefore, several investigations were conducted over the past few years to find antiviral compounds for the treatment of DENV and CHIKV infections. One attractive strategy is the screening of compounds that target enzymes involved in the replication of both DENV and CHIKV. In this review, we describe advances in the evaluation of natural products targeting the enzymes involved in the replication of these viruses.
Biological ammonium removal via heterotrophic nitrification/aerobic denitrification (HN/AD) was characterized for two isolates from a wastewater treatment station (WWTS). They were identified as ...Pseudomonas balearica UFV3 and Gordonia amicalis UFV4. Their ability to remove ammonium via NH/DA was validated by chromatography, and the influence of different physical-chemical factors on removal was evaluated. The presence of genes involved in conventional nitrification and denitrification processes was investigated via PCR and comparative genomics. Both isolates removed 100% of the ammonium in a medium containing citrate as its carbon source with a C/N ratio of 8, 3% salt, pH 7 and 30 °C. Nitrogen balance showed that approximately 55% of the ammonium removed was lost as N2(g), and 45% was assimilated. Molecular characterization revealed the absence of genes involved in autotrophic nitrification in the genome of the two isolates and the presence of genes involved in anaerobic denitrification only in P. balearica UFV3, suggesting the involvement of other genes in the HN/AD process. This was the first report of G. amicalis and P. balearica with the capability for HN/AD.
•This is the first report of G. amicalis and P. balearica with ability to HN/AD.•Isolates can remove 100% of ammonium and convert it into N2(g) within 72 h.•The ammonium removal occurs without excessive sludge production.•Genes involved in NH/DA are different from those involved in conventional process.
Mixed cultures salt acclimated showed high efficiency in heterotrophic nitrification/aerobic denitrification process in hypersaline conditions. They were able to remove 80% of ammonium in ...Heterotrophic Nitrification Medium (HNM) with 12 and 14% of salt. Above these salinity, the process still had 40% ammonium removal up to 20% of salt. Chromatography analysis validated the occurrence of the heterotrophic nitrification/aerobic denitrification process in all studied salinities (6%–20% of NaCl). However, with increasing salinity, the N2 production was smaller and took longer than the unsalted control. Microbial diversity analysis of mixed cultures showed that different groups of nitrifying microorganisms were involved in ammonium removal, including heterotrophic nitrifying/aerobic denitrifying genera such as Pseudomonas, Paracoccus, Bacillus, Halomonas, Acinetobacter and Klebsiella. In addition, this analysis also revealed that the acclimation process allowed the adaptation of the microorganisms to high saline conditions and ammonium removal up to 20% of salt. This work showed that heterotrophic nitrification/aerobic denitrification process could occur in high salinity after microbiota acclimation step, and these mixed acclimated cultures have a potential for application in hypersaline effluent treatment.
•All mixed cultures performed heterotrophic nitrification-aerobic denitrification.•Mixed cultures removed 100% of ammonium with 6 and 8% of NaCl.•Mixed cultures removed 80% of ammonium with 12 and 14% of NaCl.•Acclimation process was effective to ammonium removal in high salinity.•High potential application of mixed cultures for saline wastewater treatment.
Dengue is a neglected disease responsible for 22,000 deaths each year in areas where it is endemic. To date, there is no clinically approved dengue vaccine or antiviral for human beings, even though ...there have been great efforts to accomplish these goals. Several approaches have been used in the search for dengue antivirals such as screening of compounds against dengue virus enzymes and structure-based computational discovery. During the last decades, researchers have turned their attention to nature, trying to identify compounds that can be used as dengue antivirals. Nature represents a vast reservoir of substances that can be explored with the aim of discovering new leads that can be either used directly as pharmaceuticals or can serve as lead structures that can be optimized towards the development of new antiviral agents against dengue. In this review we describe an assortment of natural products that have been reported as possessing dengue antiviral activity. The natural products are organized into classes of substances. When appropriate, structure-activity relationships are outlined. The biological assays used to assess antiviral activity are briefly described.
The Mayaro virus (MAYV) is an endemic arbovirus in South American countries, where it is responsible for sporadic outbreaks of Mayaro fever. Clinical manifestations include fever, headache, ocular ...pain, rash, myalgia, and debilitating and persistent polyarthralgia. Understanding the mechanisms associated with MAYV-induced arthritis is of great importance due to the potential for its emergence, urbanization and dispersion to other regions.
15-day old Balb/c mice were infected by two distinct pathways, below the forelimb and in the rear footpad. Animals were observed for a period of 21 days. During this time, they were monitored every 24 hours for disease signs, such as weight loss and muscle weakness. Histological damage in the muscles and joints was evaluated 3, 7, 10, 15 and 20 days post-infection. The cytokine profile in serum and muscles during MAYV infection was evaluated by flow cytometry at different post-infection times. For pain analysis, the animals were submitted to the von Frey test and titre in different organs was evaluated throughout the study to obtain viral kinetics.
Infection by two distinct pathways, below the forelimb and in the rear footpad, resulted in a homogeneous viral spread and the development of acute disease in animals. Clinical signs were observed such as ruffled fur, hunched posture, eye irritation and slight gait alteration. In the physical test, both groups presented loss of resistance, which was associated with histopathological damage, including myositis, arthritis, tenosynovitis and periostitis. The immune response was characterized by a strong inflammatory response mediated by the cytokines TNF-α, IL-6 and INF-γ and chemokine MCP-1, followed by the action of IL-10 and IL-4 cytokines.
The results showed that Balb/c mice represent a promising model to study mechanisms involved in MAYV pathogenesis and for future antiviral testing.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
ABSTRACT
The teaching-learning process becomes more attractive when practical classes are used as part of methodological tools. Aiming (i) to stimulate the interest of high school students in the ...microbiological world and (ii) to provide didactic experience for microbiology graduate students, practical classes were undertaken. These classes were carried out during 2016 and 2017 using the infrastructure at Universidade Federal de Viçosa. Briefly, laboratory classes were prepared and taught by microbiology graduate students and an evaluation questionnaire was answered by the participants after the classes. Approximately 95% of high school students, from both years, evaluated the experience outside the school routine as very good and good; in detail, 90.09% (2016) and 100% (2017) of graduate students evaluated this experience as very good and good. The relationship between high school and graduate students also increased the curiosity of the former regarding the university environment. Accordingly, information retention regarding the ‘microbiology world’ was verified after 1 year and the students were able to remember important terms related to the microbiology class. In addition, this work allowed graduate and high school students to build a closer relationship and created an excellent teaching-learning strategy for both.
Linking high school and university allowed a greater gain in didactic experience for graduate students and retention of important microbiology terms for high school students.
Two sequential batch reactors were operated, aiming at forming aerobic granular sludge and studying the effects of the gradual increase of the NaCl concentration on the granule.
structure and ...microbial diversity, and on the efficiency of ammonia removal. The reactors were fed with ammonia-enriched synthetic effluent and 5 g L−1 of NaCl per week were applied. A decrease in the size of the granules was observed until they were completely disintegrated as the salt concentration increased up to 10 g L−1. However, the ammonia removal efficiency remained high in all the salinities applied. By sequencing the 16S rRNA amplicon gene, the microbial community structure allowed the verification of the presence of several genera affiliated with the bacteria that perform both heterotrophic nitrification and aerobic denitrification, besides those involved in the conventional nitrification and denitrification and the ANAMMOX process. Salinity affected the microbial population related to the formation and stability of the granules.
•With the increase of NaCl, the granules decreased in size until they disintegrated.•Ammonia removal remained efficient in all analyzed salinities.•There was no accumulation of nitrite or nitrate in the treated effluent.•The removal of nitrite and nitrate increased with the addition of NaCl.•Several genera of bacteria that perform the nitrification and denitrification.
The Melipona gut microbes differ from other social bees, with the absence of crucial corbiculate core gut symbionts and the high occurrence of environmental strains. We studied the microbial ...diversity and composition of three Melipona species and their honey to understand which strains are obtained by horizontal transmission (HT) from the pollination environment; or represent symbionts co-evolved with Melipona by HT from the hive/food stores or vertical transmission (VT) via social interactions. Bees harbored higher microbial alpha diversity and a different and more species-specific bacterial composition than honey. Otherwise, the fungal communities of bee and honey samples are less dissimilar. As expected, the core symbionts Snodgrassella and Gilliamella were absent in bees that had a prevalence of Lactobacillus Firm-5, environmental Lactobacillaceae, Bifidobacteriaceae and Acetobacteraceae. Also, Pectinatus and Floricoccus have habitat preferences for bees, putatively representing novel symbionts from the environment that co-evolved via VT among generations. Fructilactobacillus found in bees possibly had HT to bees from honey stores. Metschnikowia yeasts, consistent in all bees and honey samples, might have HT to bees from food stores. Similarly, Saccharomycetales might have HT from honey or plants/flowers to bees. This work contributes to the understanding of Melipona symbionts and their modes of transmission.
The development of new drugs is a very complex and time-consuming process, and for this reason, researchers have been resorting heavily to drug repurposing techniques as an alternative for the ...treatment of various diseases. This approach is especially interesting when it comes to emerging diseases with high rates of infection, because the lack of a quickly cure brings many human losses until the mitigation of the epidemic, as is the case of COVID-19. In this work, we combine an in-house developed machine learning strategy with docking, MM-PBSA calculations, and metadynamics to detect potential inhibitors for SARS-COV-2 main protease among FDA approved compounds. To assess the ability of our machine learning strategy to retrieve potential compounds we calculated the Enrichment Factor of compound datasets for three well known protein targets: HIV-1 reverse transcriptase (PDB 4B3P), 5-HT2A serotonin receptor (PDB 6A94), and H1 histamine receptor (PDB 3RZE). The Enrichment Factor for each target was, respectively, 102.5, 12.4, 10.6, which are considered significant values. Regarding the identification of molecules that can potentially inhibit the main protease of SARS-COV-2, compounds output by the machine learning step went through a docking experiment against SARS-COV-2 Mpro. The best scored poses were the input for MM-PBSA calculations and metadynamics using CHARMM and AMBER force fields to predict the binding energy for each complex. Our work points out six molecules, highlighting the strong interaction obtained for Mpro-mirabegron complex. Among these six, to the best of our knowledge, ambenonium has not yet been described in the literature as a candidate inhibitor for the SARS-COV-2 main protease in its active pocket.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The rupture of the Fundão Dam containing iron‐rich mining tailings, in 2015, was one of the worst environmental disasters in Brazil. The deposition of tailings has generated serious impacts on the ...soil and, as microorganisms play an important role in these environments, the recovery of the microbial community is a critical step in restoring the soil for sustainable use. Soil microorganisms and their activities are recognized as sensitive bioindicators for environmental changes; however, few experiments have been conducted to investigate the response of the microbial community to the magnitude of the impact caused by the Fundão Dam rupture and the effect of the use of revegetation natural or induced for ecosystem recovery, especially in Brazil. This study aimed to evaluate the dynamics of community structure and putative functions, over time, in response to the deposition of the tailings on the soil by bacterial 16S rRNA sequencing. We evaluated an area affected by tailings, covered with natural and induced revegetation. The results revealed a temporal dynamic of the soil microbiota, which demonstrates that the microbial community structure of these areas differed, mainly in less abundant taxa, and the induced revegetation area was closer to the forest than natural revegetation. These results reveal the importance of implementing revegetation programs to accelerate the initial recovery. Functions related to the use of alternative electron acceptors differed, possibly due to the greater compaction of the affected soil. Despite the improvement of the impacted areas over time, the strong effect of tailings deposition on the bacterial community structure can still be noticed.
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