The emergence and spread of resistant microorganisms have raised concerns of a looming global infectious disease crisis. In addition, in recent years the increase in resistant microorganisms has been greater than the introduction of new therapeutic alternatives capable of combating them. Among the most important resistant microorganisms is Staphylococcus aureus, a Gram-positive bacterium responsible for causing an increase in infections. The high capacity of this pathogen to acquire and accumulate resistance mechanisms makes it particularly worrisome. Efflux pumps are known mechanisms that mediate the resistance of S. aureus to several classes of antibiotics. Thus, several studies have been carried out in order to find new therapeutic alternatives with antibacterial activity and that are capable of inactivating this resistance mechanism. In this context, chalcones show promise compounds, due to their ease of synthesis, a large number of biological activities and few toxic side effects. The aim of this study was to evaluate the antibacterial activity of chalcone (2E)-3-({4-[(2E)-3-(4-nitrophenil)prop-2-enol]phenyl}carbamoyl)prop-2-enoic acid, called CAP, as well  as its action on Staphylococcus aureus K2068 strain carrying the MepA efflux pump. The determination of the Minimum Inhibitory Concentration (MIC) was performed through the broth microdilution methodology and the analysis of chalcone on the efflux pump was performed using ethidium bromide as a maker. These results obtained in this study showed that chalcone CAP was not able to potentiate the action of the antibiotic ciprofloxacin and was not able to inhibit the efflux pump.

The discovery and use of bacteria allowed the treatment of infections and the reduction of mortality rates associated with bacterial pathogens. However, simultaneously, bacterial pathogens progressed to antibiotic resistance. Added to this, today antibiotics are no longer produced as they were in the previous century and this is due to costs and profitability compared to the manufacture of other medicines. These determinants raise the need to develop new therapeutic alternatives. For a long time, public health policies have resorted to drugs of last resort or increasing the pharmacological concentrations of antibiotics, but these strategies, despite being immediate, are insufficient and make the treatment of infections more expensive, in addition to resulting in an increase in adverse effects. Therefore, to be considered promising, a medicine needs to have a well-defined structure. Polyoxometalates (POM’s) represent a class of inorganic compounds with a diversity of functions, sizes and chemical composition, characteristics currently being targeted. The writing plan for this study is divided into two important axes: 1- an integrative and bibliometric review of the literature and 2- carrying out chemical characterization and microbiological activity tests. The integrative and bibliometric survey was carried out using the Scopus and Web of Science databases using the descriptors “Polyoxometalates” and “Polyoxometalates and antibacterial activity”. From this, 38 and 36 articles were selected, respectively, for each indexed database. Bibliometrics presented the relationship between the keywords of the selected articles and data about bibliographic coupling. The latter demonstrated that, of the total number of studies surveyed, 27 were correlated in Scopus and 31 in Web of Science. The predominance graphs allowed us to verify that the bacteria most used in studies are Escherichia coli and Staphylococcus aureus, using the microdilution method. The chemical characterization of the compounds occurred by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), revealing a pattern of bands for the compounds that were located between 84-1915 cm^-¹. Using serial microdilution methodology, with colorimetric development, microbiological studies investigated the direct effect of the compounds on the clinically important bacteria Escherichia coli and Staphylococcus aureus, and the subinhibitory effect combined with traditional antibiotics was also verified. To evaluate the inhibition of beta-lactamase activity, the ability of the compounds to reduce the MIC of ampicillin against multiresistant strains of Staphylococcus aureus K-4414 and K-4100 was verified. Molybdates and tungstates did not present direct antibacterial activity, however they potentiated the effect of the traditional antibiotics ampicillin and gentamicin, in different circumstances against the bacteria Escherichia coli 06 and Staphyloccocus aureus 10. Molybdic acid, potassium molybdate, calcium tungstate and calcium tungstate inhibited the resistance effect presented by the bacteria S. aureus-K4100 and K4414. Given the current resistance scenario, these results represent new alternatives for the treatment of bacterial infections, allowing a better understanding of the properties of POMs. These results are pioneering in terms of publication.

Urochloa brizantha cultivar piatã is a tropical forage widely cultivated for its nutritive
value and adaptability to low fertility soils. However, the growth of this forage grass is
threatened when soils contain high levels of salts. Salinity alters the ionic balance and
the redox state of the plant, causing alterations that contribute to the loss of plant
productivity. In this sense, reliable methods are needed to mitigate the effects generated
by saline stress, and the application of plant hormones is an efficient way for such
purposes. The aim of this study is to evaluate the salt stress tolerance responses in U.
brizantha when treated with indoleacetic acid (IAA). Initially, experiments were carried
out to select an adequate concentration of the hormone (50, 200 and 800 µM) via foliar
application in plants subjected to saline stress with NaCl at 100 mM. Analysis of growth
by weighing and length measurements of aerial and root tissues, determination of
sodium and potassium contents by flame photometry, and spectrophotometric
methodologies for analysis of chlorophyll, carotenoid, proline and lipid peroxidation
contents were carried out. The results showed that at lower concentrations of AIA there
was a better regulation of Na+ levels, an increase in the content of photosynthetic
pigments and a reduction of proline in stressed plants. Therefore, a second experiment
was developed with the foliar application of AIA at 50 µM in plants subjected to saline
stress with NaCl at 75 mM. In this experiment, the analyzed parameters in previous
experiment were evaluated and it were included the follow analysis: relative water
content, electrolyte leakage, content of hydrogen peroxide and enzyme activity of
catalase (CAT), guaiacol peroxidase (POD) and superoxide dismutase (SOD). POD
enzymatic activity was also evaluated by zymography. The results showed that
treatment with AIA in stressed plants did not promote plant growth and stimulate
enzyme activity, however it was observed a reduction in electrolyte leakage, lipid
peroxidation and hydrogen peroxide, as well as a decrease in sodium levels and
potassium retention in piatã grass leaves, revealing a possible participation of AIA in
the regulation of ionic homeostasis. It is concluded that AIA would induce salt stress
tolerance in U. brizantha by acting on processes that control sodium and potassium
transport to the aerial tissues.

Lectins are natural bioactive proteins found in bacteria, fungi, animals, and plants, capable of interacting with oligosaccharides, monosaccharides, and glycoconjugates through a carbohydrate recognition domain. Plant lectins, especially those from legumes, have been extensively studied because they have various biological effects, including the ability to inhibit fungal growth. Due to their fungicidal activity and biodegradability, plant lectins can be used to control diseases caused by phytopathogenic fungi. Therefore, this work sought to evaluate the inhibitory effect of lectins from Vatairea macrocarpa (VML) and Parkia platycephala (PPL) on the growth of phytopathogenic fungi Colletotrichum okinawense, C. siamense, Lasiodiplodia theobromae and Rhizoctonia solani AG-4 HGI. Therefore, the lectins were purified by affinity chromatography, lyophilized, and tested for purity by SDS-PAGE and hemagglutinating activity. To test the inhibitory effect of lectins, fungal isolates were cultured in PDA medium containing VML (1000 μg/mL) and PPL (100 and 200 μg/mL), separately. As positive controls, pencycuron and methyl thiophanate fungicides were used. Plates containing only BDA were used as controls. The growth of C. siamense (isolate CMM 4081) reduced with the use of methyl thiophanate and PPL lectin at 200 μg/mL, without differing from each other, but differing from the other treatments. In the presence of the PPL lectin at 200 μg/mL, the growth of the L. theobromae isolate CMM 2295 was lower than that observed in the control. The VML lectin effectively reduced the mycelial growth of the L. theobromae isolate CMM 4039, similar to that observed with methyl thiophanate. The VML and PPL lectins did not show inhibitory activity on the growth of C. okinawense and R. solani. The inhibitory activity of these lectins can be species-dependent regarding Colletotrichum and isolated-dependent in relation to L. theobromae. The results encourage future research with lectins aimed at obtaining formulations to control diseases caused by fungi in post-harvest plants.

Azithromycin (AZT) is among the most successful and highly prescribed antibiotics in the world, being used in first-line treatment for respiratory tract infections, sexually transmitted diseases, dermal infections, and other bacterial manifestations. However, when it is necessary to measure the levels of this active ingredient in complex matrices, or even when you want to study the reactivity and stability of the molecule, the number of analytical possibilities with the necessary requirements for these purposes is still limited. In this work, an innovative proposal was developed with an electrochemical sensor based on cerium molybdate (Ce₂(MoO₄)₃) and multi-walled carbon nanotubes (MWCNT) integrated into a conductive carbon paste. Despite the high reactivity of the materials present in the resulting device (Ce₂(MoO₄)₃-MWCNT/EPC) to analyze the oxidation of the antibiotic, experimental data and computational simulations revealed that the solubility and electroactivity of the antibiotic improve in alkaline electrolyte (pH = 8) prepared in a binary mixture of CH₃OH/H₂O (10:90%, v/v). The charge transfer resistance and, consequently, the sensitivity of the device also improved after the heat treatment of Ce₂(MoO₄)₃-MWCNT/EPC, as a way to eliminate the reticular water contained in the molybdate microcrystals. There is evidence that the oxidation of the antibiotic on the electrochemical sensor occurs irreversibly, losing 2e^‒ of desosamine. After optimizing the electroanalytical parameters, it was possible to detect AZT with a detection limit of 230 nm, in addition to high precision of the results, demonstrated by results deviations below 4.5%. The device showed applicability to evaluate the thermo-oxidative stability of AZT under varying conditions of temperature, ultraviolet radiation and atmospheric air saturation. The results strengthened the idea that quality control of AZT-based medicines must be carried out continuously, using non-ideal laboratory standards and closer to those observed during transport, storage and administration of the products, as a way of making a more rigorous assessment of the validity and viability of the active ingredient in formulations, as well as ensuring the health of consumers.

Carbohydrates are the most abundant organic molecules on the planet, being important in
mechanisms of intercellular recognition and interaction and for health. Different ways of
controlling glucose levels have been the subject of much research aimed at facilitating and/or
improving the detection of this monosaccharide in biological fluids, foods and commercial
formulations. Due to their ability to reversibly and specifically bind carbohydrates, lectins are
proteins that have been gaining ground as a recognition star in the development of
electrochemical glucose biosensors. Legume lectins are widely studied and characterized,
with the basic lectin from Canavalia ensiformes (ConA) being the best-known of this group.
Due to the diversity of properties according to the source of production, fungal lectins also
show biotechnological potential. The species Ganoderma applanatum, for example, has a
lectin (GAL) with an affinity for glucose and which is moderately resistant to variations in pH
(4 - 8) and temperature (20 – 60 ºC), although with a hemagglutinating activity that is better
preserved under physiological conditions. In this work, two biorecognition systems for
glucose were developed with ConA and GAL, using a glassy carbon electrode (GCE)
modified with hexacyanometalate Prussian Blue (PB) which, in addition to being a
semiconductor material, has heterogeneous electron density regions and suitable for the
adsorption of proteins, through intermolecular bonds. The results obtained by different
techniques proved that the problem of PB instability at physiological pH can be solved by
thermal treatment at 100 ºC for 1h, leading to the electrode support of ta-PB/GCE. The use of
artificial intelligence associated with electrochemical parameters allowed structural studies
and the collection of data on biocompatible and electrostatically favorable conditions for
immobilization of GAL in ta-PB/GCE, which were also useful in studies with ConA. The
GAL/ta-PB/GCE biosensor showed excellent electrochemical performance for glucose
quantification under ideal conditions, reaching a detection limit of 10.2 pM and sensitivity of
0.012 µA µM ‒1 cm ‒2 . The performance obtained with ConA/ta-PB/GCE was satisfactory,
reaching a detection limit of 0.96 µM and sensitivity of 3.94×10 3 µA µM ‒1 cm ‒2 . The
selectivity of the assays was influenced by other carbohydrates, including fructose, maltose
and sucrose, probably due to the moderately low regioselectivity achieved with surface
interaction sites of these proteins, but without compromising the viability of the devices for
the electroanalysis of glucose in complex samples. Both biosensors were tested for glucose
quantification in pharmaceutical formulations, achieving recovery values between 98.0% and

100.5%. The ConA/ta-PB/GCE biosensor was successfully applied for the analysis of total
sugars in a soft drink sample. Each device presented particular advantages and challenges that
still require further studies, but the set of figures of merit obtained in each system proved that
the platforms developed are truly efficient for the analysis of glucose in different samples,
stimulating further research with the development of electrochemical biosensors based on
lectins for carbohydrates of biological relevance.

The leishmaniases are characterized as a set of diseases of clinical and epidemiological interest with worldwide distribution. The treatment for this disease is based primarily on the use of pentavalent antimonials (Sb ⁺⁵), which in Brazil is the meglumine antimonate (Glucantime®) and in some cases the application of secondary drugs such as amphotericin B. These drugs, despite being efficient, present several problems in their use and important side effects, which encourages the search for new drugs that present low toxicity and few adverse effects. Within this scenario, lectins stand out as proteins that have several functions in the organisms where they are found. The present study aimed to evaluate the in vitro leishmanicidal effect of lectin from D. violacea seeds (DVL) in Leishmania infantum strain culture. Promastigote forms were incubated with different concentrations of DVL (324 - 5.06 μg/mL) and cell viability was assessed by counting in a Neubauer chamber. From the determination of the CI₅₀ the participation of the carbohydrate recognition domain (CRD) in the lectin activity was evaluated. Fluorescence assays with 2',7'-dichlorodihydrofluorescein diacetate (DCFH2-DA) and propidium iodide (PI) were performed in order to verify the production of reactive oxygen species (ROS) and damage to parasite cell membrane integrity, respectively. In addition, the morphological changes induced by the DVL in promastigotes were evaluated by scanning electron microscopy. The effect of the association between the DVL and amphotericin B and glucantime on promastigotes was also tested. By means of the 3-(4,5-Dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) test it was possible to determine the cytotoxicity of the DVL on Raw 264.7 macrophages, as well as the effect of its association with amphotericin B on these same cells. Furthermore, the effect of DVL on amastigotes of the L. infantum strain was also verified. DVL was able to inhibit the growth of promastigotes in a concentration and time dependent manner, with CI_50/24h = 49.37 μg/mL; CI_50/48h = 37.47 μg/mL; CI_50/72h = 34 μg/mL. The data obtained showed that the lectin activity is related to its ability to recognize and bind to glycans present in L. infantum and treatment with it is able to induce the production of ROS, damage to cell membrane integrity and morphological changes in the parasites. Furthermore, the lectin was able to modulate the action of amphotericin B and glucantime, improving their effect on promastigotes.  DVL did not show cytotoxicity in Raw 264.7 cells, demonstrating an increase in the viability of these cells, an effect also observed in the evaluation of the association between DVL and amphotericin B on the cells. Furthermore, with the use of CI₅₀ (50 μg/mL) it was possible to observe a reduction in the survival rate of macrophages infected with amastigotes, as well as a reduction in the percentage of infection. The results suggest that DVL is a promising alternative for the treatment of leishmaniasis, however, further studies are needed to elucidate the probable mechanisms of action.

Oxidative stress, characterized by the accumulation of reactive oxygen species (ROS), is implicated in the pathogenesis of several diseases, including cardiac hypertrophy. Although ROS are essentials for several physiological processes, excessive amounts may damage cardiomyocyte components, compromising their function and thus triggering a number of adverse changes such as cardiac fibrosis, impaired contraction, cell death by necrosis and apoptosis. The mitochondrial electron transport chain (ETC) is a known source of ROS. Because mitochondria account for about 25% of the mass of cardiomyocytes, they are considered one of the most significant sources of ROS in the heart. Thus, mitochondria have been the target of several studies using cardiac hypertrophy models. The flavonoid quercetin, is a potent ROS scavenger and having several beneficial effects on the cardiovascular system, including antihypertrophic effects. In this work, we tested whether quercetin could attenuate the cardiac hypertrophy by improving the redox balance and mitochondrial homeostasis. To this hypothesis we treated mice with intraperitoneal injections of isoproterenol (30 mg/kg/day) for 4 consecutive days. On the fifth day, some of these animals were euthanized and the remaining mice were relocated to two subgroups. From that point on, one group received only isoproterenol (ISO group) (30 mg/kg/dia) and another group received isoproterenol and quercetin (ISO+QUE group) orally (10 mg/kg/day) for 4 more days. The animals treated with ISO for 4 days showed increased cardiac weight/tibia length ratio, increased total protein content, decreased sulfhydryl protein content, compromised antioxidant enzyme activity and high H₂O₂ production. Intervention with quercetin treatment from this point on was able to attenuate cardiac hypertrophy, reestablish sulfhydryl protein levels and antioxidant activity, in addition to effectively blocking the H₂O₂ production. In addition, we observed that isoproterenol hypertrophic stimulation decreases mitochondrial superoxide dismutase (MnSOD) expression and activity, while quercetin reverses this effect. Quercetin also protects mitochondria against opening of mitochondrial permeability transition pore (mPTP) in vivo and in vitro. Taken together, these results show that quercetin is able to attenuate isoproterenol-induced cardiac hypertrophy by improving mitochondrial function and redox balance.

The fungus of the genus Rhizoctonia causes one of the main diseases of cowpea, the most important food legume in the Northeast of Brazil and with large planted area in the Cariri cearense region. The identification of this fungus is based mainly on the classification into hyphal anastomosis groups (AGs). The present study was undertaken to determine: a) which Rhizoctonia species and AGs that occur in cowpea production areas in Cariri cearense using internal transcribed spacer region (ITS) sequencing of ribosomal DNA (rDNA), and b) the variation in aggressiveness among the different AGs associated with this legume. Cowpea plants with stem and root rot symptoms, typical of those induced by Rhizoctonia, were collected in 32 production areas located in 18 municipalities of Cariri cearense, during 2018 and 2019. From symptomatic plant materials were performed isolations of the associated fungi and obtained Rhizoctonia pure cultures. Forty-one Rhizoctonia isolates were obtained from cowpea areas in Cariri cearense. Genomic DNA was extracted from all Rhizoctonia isolates and PCR amplifications from the ITS-rDNA region were made with the ITS1 and ITS4 primers. PCR products were purified and sequenced. Nucleotide sequences from Rhizoctonia reference isolates obtained from GenBank were included in the analyzes and phylogenetic relationships were analyzed by Maximum Likelihood methods. The pathogenicity and aggressiveness of isolates representing the AGs identified were tested on cowpea plants. Phylogenetic analysis of the ITS region allowed the identification of four AGs, two from R. solani (AG-4 HGI and AG-4 HGIII) and two from Rhizoctonia binucleate (AG-Fa and AG-L). This is the first report worldwide of the association of AG-4 HGIII, AG-Fa and AG-L with cowpea. AG-4 HGI was the most frequent (53.7%), being widely distributed in Cariri cearense. Among the cowpea producing municipalities in this region, Mauriti presented the highest diversity of AGs (AG-4 HGI, AG-4 HGIII and AG-Fa). All isolates were pathogenic to cowpea and there was a difference in aggressiveness between the different isolates within the same Rhizoctonia AG. To our knowledge, this is the first detailed report of the AG composition of Rhizoctonia associated to cowpea in Cariri cearense and expands the knowledge on this subject in Brazil and in the world.

Cardiac hypertrophy is a compensatory response of the heart to an increase in blood pressure or volume. Although it is a temporary beneficial response, it often leads to hypertrophic cardiomyopathy and congestive heart failure. Caloric restriction (CR) is a powerful intervention to improve health and delay of aging, its effects involve improve-ment in energy metabolism and oxidative stress, in which mitochondria play a central role. Mitochondria have an ATP-sensitive K+ channels (mitoKATP), whose opening leads to cellular protection through mechanisms related to the reduction of cellular oxidative stress. This paper investigated the role of CR in the prevention of isoproterenol-induced cardiac hypertrophy in vivo by preventing the production of reactive oxygen species and maintaining antioxidant activity. Additionally, we investigated the involvement of mi-toKATP in cardiac hypertrophy. In order to establish a protocol for induction of caloric restriction in mice, we counted (in grams) the standard diet consumption of Swiss mice for 2 weeks. After this period the animals were randomly divided into two groups: ad libitum (AL group) and fed with 60% of the average calorie intake (RC group - calculated as above) for an additional 4 weeks. To induce cardiac hypertrophy, mice were treated with isoproterenol (ISO) (30 mg / kg / day) for 8 days. For inhibition of mitoKATP, bloc-kers, 5-hydroxydecanoate (5-HD) (10 mg / kg / day) and glybenclamide (GLI) (6 mg / kg / day) were used from the 5th day. Isoproterenol-treated mice had elevated heart weight/tibia length ratios and cardiac protein levels. These gross hypertrophic markers were significantly reduced in CR mice. Cardiac tissue from isoproterenol-treated CR mice also produced less H2O2 and had lower protein sulfydryl oxidation. Additionally, calorie restriction blocked hypertrophic-induced antioxidant enzyme (catalase, superoxide dis-mutase and glutathione peroxidase) activity repression during cardiac hypertrophy. Re-markably, mitoKATP activity has been shown to be repressed in isolated mitochondria from hypertrophic hearts, in a manner sensitive to CR. Finally, as evidence of the princi-ple of mitoKATP involvement in protection against hypertrophy we found that pharmaco-logical inhibition of mitoKATP (using 5-HD and GLI) significantly blocked the protective effects of CR. Together these data suggest that CR improves redox balance during car-diac hypertrophy, and performs this process in a mechanism involving mitoKATP activation.