Bee Venom Toxic Effect on MDA-MB-231 Breast Cancer Cells and Caenorhabditis Elegans

INTRODUCTION

Bee venom has therapeutics and pharmacological properties. Further toxicological studies on animal models are necessary due to the severe allergic reactions caused by this product.

METHOD

Here, Caenorhabditis elegans was used as an in vivo toxicity model, while breast cancer cells were used to evaluate the pharmacological benefits. The bee venom utilized in this research was collected from Apis mellifera species found in Northeast Brazil. The cytotoxicity caused by bee venom was measured by MTT assay on MDA-MB-231 and J774 A.1 cells during 24 - 72 hours of exposure. C. elegans at the L4 larval stage were exposed for three hours to M9 buffer or bee venom. Survival, behavioral parameters, reproduction, DAF-16 transcription factor translocation, the expression of superoxide dismutase (SOD), and metabolomics were analyzed. Bee venom suppressed the growth of MDA-MB-231 cancer cells and exhibited cytotoxic effects on macrophages. Also, decreased C. elegans survival impacted its behaviors by decreasing C. elegans feeding behavior, movement, and reproduction.

RESULTS

Bee venom did not increase the expression of SOD-3, but it enhanced DAF-16 translocation from the cytoplasm to the nucleus. C. elegans metabolites differed after bee venom exposure, primarily related to aminoacyl- tRNA biosynthesis, glycine, serine and threonine metabolism, and sphingolipid and purine metabolic pathways. Our findings indicate that exposure to bee venom resulted in harmful effects on the cells and animal models examined.

CONCLUSION

Thus, due to its potential toxic effect and induction of allergic reactions, using bee venom as a therapeutic approach has been limited. The development of controlled-release drug strategies to improve this natural product's efficacy and safety should be intensified.

Evaluation of the hydroalcoholic extract of Clarisia racemosa as an antiparasitic agent: an in vitro approach

Clarisia racemosa Ruiz & Pav is a neotropical species found in humid forests from southern Mexico to southern Brazil. There are few studies related to the ethnopharmacological use of C. racemosa. Our objective was to evaluate the hydroalcoholic extract of C. racemosa as a potential antiparasitic agent. For this, we performed in vitro assays against strains of Leishmania amazonensis, Trypanosoma cruzi, Plasmodium falciparum, and Schistosoma mansoni. At the same time, immunomodulatory activity tests were carried out. The results demonstrated that the extract was able to stimulate and activate immune cells. In preliminary antiparasitic tests, structural modifications were observed in the promastigote form of L. amazonensis and in adult worms of S. mansoni. The extract was able to inhibit the growth of trypomastigote form of T. cruzi and finally showed low antiparasitic activity against strains of P. falciparum. It is pioneering work and these results demonstrate that C. racemosa extract is a promising alternative and contributes to the arsenal of possible forms of treatment to combat parasites.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03799-2.

High prevalence of pathogenic Eimeria spp. and the main risk factors associated with infection in goats from a semiarid region of Northeastern Brazil

This study aimed to analyze the epidemiology of infections caused by Eimeria spp. in goats bred in an extensive production system in Northeast Brazil. To this end, an epidemiological survey was performed, wherein 350 fecal samples were collected from goats ranging from 3 months to 8 years old across 30 farms. The number of oocysts per gram of feces (OPG) was counted using the Mini-FLOTAC method. Species were identified based on their morphological and morphometric characteristics. Frequencies between animal categories were assessed using the chi-square test and known risk factors after multivariate analysis. Eimeria oocysts were found in 99.4% (346/348) of samples and 100% (30/30) of the farms. The OPG was influenced by the age of the animals; therefore, young goats (up to 6 months old) eliminated more oocysts (2302.6 + 5454.8) than adult goats (881.7 + 1551.5). Three pathogenic species were identified, with two demonstrating a high prevalence: Eimeria arloingi (88.83%) and Eimeria christenseni (44.7%), in addition to Eimeria caprina (3.72%). In the study, the habit of ground feeding and the use of cisterns as water sources were identified as risk factors, with odds ratios of 4.04 and 9.82, respectively. However, cleaning facilities at shorter intervals was a protective factor (OR = 0.19). We concluded that there was a high prevalence of Eimeria infection in goats bred in extensive production systems, even those in semiarid regions. This high prevalence can be attributed to the congregation of animals in shaded areas and the substantial accumulation of fecal matter at night.

In vitro inhibition and eradication of multidrug-resistant Acinetobacter baumannii biofilms by riparin III and colistin combination

Acinetobacter baumannii, a prominent emerging pathogen, is responsible for persistent and recurrent healthcare-associated infections (HAIs). Its bacterial resistance and virulence factors, such as biofilm formation, contribute to its survival in hospital environments. Combination therapy has proven to be an effective approach for controlling these infections; however, antimicrobial resistance and compound toxicity can hinder antimicrobial efficacy. Numerous in vitro studies have demonstrated the synergistic effect of antimicrobials and natural products against multidrug-resistant (MDR) A. baumannii biofilm. Riparin III, a natural alkamide derived from Aniba riparia (Nees) Mez., possesses various biological activities, including significant antimicrobial potential. Nonetheless, no reports are available on the use of this compound in conjunction with conventional antimicrobials. Hence, this study aimed to investigate the inhibition and eradication of A. baumannii MDR biofilm by combining riparin III and colistin, along with potential ultrastructural changes observed in vitro. Clinical isolates of A. baumannii, known for their robust biofilm production, were inhibited, or eradicated in the presence of the riparin III/colistin combination. Furthermore, the combination resulted in several ultrastructural alterations within the biofilm, such as elongated cells and coccus morphology, partial or complete disruption of the biofilm's extracellular matrix, and cells exhibiting cytoplasmic material extravasation. At the synergistic concentrations, the riparin III/colistin combination exhibited a low hemolytic percentage, ranging from 5.74% to 6.19%, exerting inhibitory and eradicating effects on the A. baumannii biofilm, accompanied by notable ultrastructural changes. These findings suggest its potential as a promising alternative for therapeutic purposes.

In vitro activity, ultrastructural analysis and in silico pharmacokinetic properties (ADMET) of thiazole compounds against adult worms of Schistosoma mansoni

The present work aimed to carry out in vitro biological assays of thiazole compounds against adult worms of Schistosoma mansoni, as well as the in silico determination of pharmacokinetic parameters to predict the oral bioavailability of these compounds. In addition to presenting moderate to low cytotoxicity against mammalian cells, thiazole compounds are not considered hemolytic. All compounds were initially tested at concentrations ranging from 200 to 6.25 μM against adult worms of S. mansoni parasites. The results showed the best activity of PBT2 and PBT5 at a concentration of 200 μM, which caused 100% mortality after 3 h of incubation. While at 6 h of exposure, 100% mortality was observed at the concentration of 100 µM. Subsequent studies with these same compounds allowed classifying PBT5, PBT2, PBT6 and PBT3 compounds, which were considered active and PBT1 and PBT4 compounds, which were considered inactive. In the ultrastructural analysis the compounds PBT2 and PBT5 (200 µM) promoted integumentary changes with exposure of the muscles, formation of integumentary blisters, integuments with abnormal morphology and destruction of tubercles and spicules. Therefore, the compounds PBT2 and PBT5 are promising antiparasitics against S. mansoni.

In Vitro Anthelminthic Activity and Ultrastructural Analysis of Barbatic Acid against Schistosomulae and Juvenile Worms of Schistosoma mansoni

Schistosomiasis affects about 260 million people worldwide and the search for new schistosomicidal compounds is urgent. In this study we evaluated the in vitro effect of barbatic acid against schistosomulae and young worms of Schistosoma mansoni. The barbatic acid was evaluated through the bioassay of motility and mortality, cellular viability and ultrastructural analysis of juvenile stages through Scanning Electron Microscopy. Barbatic acid showed a schistosomicidal effect against schistosomulae and young worms of S. mansoni after 3 h of exposure. At the end of 24 h, barbatic acid showed 100 %, 89.5 %, 52 % and 28.5 % of lethality for schistosomulae at the concentrations of 200, 100, 50 and 25 μM, respectively. For young worms, barbatic acid showed 100 % and 31.7 % of lethality at the concentrations of 200 and 100 μM, respectively. Motility changes were observed at all sublethal concentrations. There was a significant reduction in the viability of young worms after exposure to barbatic acid at 50, 100 and 200 μM. Extensive damage to the schistosomulae and young worm's tegument, was observed from 50 μM. This report provides data showing the schistosomicidal effect of barbatic acid on schistosomulae and young worms of S. mansoni, causing death, motility changes and ultrastructural damage to worms.

Pomegranate sarcotesta lectin (PgTeL) inhibits planktonic growth and disrupts biofilm formed by Cryptococcus neoformans

AIMS

We investigated the putative fungistatic and fungicidal activities of pomegranate sarcotesta lectin (PgTeL) against Cryptococcus neoformans B3501 (serotype D), specifically the ability of PgTeL to inhibit yeast capsule and biofilm formation in this strain.

METHODS AND RESULTS

PgTeL showed a minimum inhibitory concentration of 172.0 μg ml-1, at which it did not exhibit a fungicidal effect. PgTeL concentrations of 4.0-256.0 μg ml-1 reduced biofilm biomass by 31.0-64.0%. Furthermore, 32.0-256.0 μg/mL PgTeL decreased the metabolic activity of the biofilm by 32.0-93.0%. Scanning electron microscopy images clearly revealed disruption of the biofilm matrix. Moreover, PgTeL disrupted preformed biofilms. At concentrations of 8.0-256.0 μg ml-1, PgTeL reduced metabolic activity in C. neoformans by 36.0-92.0%. However, PgTeL did not inhibit the ability of B3501 cells to form capsules under stress conditions.

CONCLUSIONS

PgTeL inhibited biofilm formation and disrupted preformed biofilms, demonstrating its potential for use as an anticryptococcal agent.

Structural design, synthesis, and anti-Trypanosomatidae profile of new Pyridyl-thiazolidinones

The present work reports the synthesis of a novel series of pyridine-thiazolidinones with anti-Trypanosoma cruzi and leishmanicidal activities (compounds 10-27), derived from 2 or 4-pyridine thiosemicarbazones (1-9). The in vitro assays were performed with Trypanosoma cruzi trypomastigotes and amastigotes, as well as with Leishmania amazonensis promastigotes and amastigotes. The cytotoxicity profile was evaluated using the cell line RAW 264.7. From the 18 pyridine-thiazolidinones, 5 were able to inhibit trypomastigotes. Overall, all compounds inhibited amastigotes, highlighting compounds 15 (0.60 μM), 18 (0.64 μM), 17 (0.81 μM), and 27 (0.89 μM). Compounds 15 and 18 were able to induce parasite cell death through necrosis induction. Analysis by scanning electron microscopy showed that T. cruzi trypomastigotes treated with compounds 15 and 18 induced morphological changes such as shortening, retraction and curvature of the parasite body and leakage of internal content. Regarding the antiparasitic evaluation against Leishmania amazonensis, only compound 27 had a higher selectivity compared to Miltefosine against the amastigote form (IC₅₀ = 5.70 μM). Our results showed that compound 27 presented an antiparasitic activity for both Trypanosoma cruzi and Leishmania amazonensis. After in silico evaluation, it was suggested that the new pyridine-thiazolidinones had an appropriate drug-likeness profile. Our results pointed out a new chemical frame with an anti-Trypanosomatidae profile. The pyridine-thiazolidinones presented here for the first time could be used as a starting point for the development of new antiparasitic agents.

Probing the Cr3+ luminescence sensitization in β-Ga2O3 with ion-beam-induced luminescence and thermoluminescence

Ion-beam-induced luminescence (IBIL) measurements were performed in Cr-doped β-Ga₂O₃ using both protons and helium ions, showing a strong enhancement of the Cr³⁺ luminescence upon ion irradiation. Theoretical modelling of the IBIL intensity curves as a function of the fluence allowed estimating the effective cross-sections associated with the defect-induced IBIL enhancement and quenching processes. The results suggest that sensitizing the Cr³⁺ luminescence is more efficient for H⁺ than for He⁺ irradiation. Thermoluminescence (TL) studies were performed in the pristine sample, with no TL signal being observed in the spectral region corresponding to the Cr³⁺ emission. In agreement with the IBIL study, upon ion irradiation (with either protons or helium ions), this TL emission is activated. Moreover, it can be quenched by annealing at 923 K for 10 s, thus revealing the role played by the defects induced by the irradiation. These results show that the irradiation-induced defects play a major role in the activation of the Cr³⁺ luminescence, a fact that can be exploited for radiation sensing and dosimetry.

Synthesis, in vitro schistosomicidal activity and ultrastructural alterations caused by thiosemicarbazones and thiazolidinones against juvenile and adult Schistosoma mansoni worms (Sambon, 1907)

Schistosomiasis is a neglected disease that affects about 258 million people worldwide. Caused by Schistosoma mansoni, helminth which, in Brazil, it is present on 19 states and capital. Praziquantel (PZQ) treatment presents low efficacy and adverse effects in parasites juvenile stages. Thiosemicarbazones and thiazolidinones are rising as potent chemical groups that have biological activity wide spectrum, and with radical modifications, they may become more effective and selective. Aiming to evaluate the action of these molecules against S. mansoni, JF series thiosemicarbazones and thiazolidinones (LqIT/UFPE) were synthesized: JF30, JF31, JF33, JF34, JF35, JF36, JF38, JF39, JF42 and JF43. Several parameters were evaluated, such as: their cytotoxicity in VERO cells, in vitro schistosomicidal activity for juvenile and adult worms and their action on worms through ultrastructural changes. Cytotoxicity indices ranged from 272 µM to 725 µM. When evaluating mortality rate, adult and juvenile worms showed 100 % mortality rate within 24 h and 48 h, respectively, when exposed to the compounds JF31 and JF43 at a dose of 200 µM. Also, motility, mortality and oviposition parameters were evaluated: JF31 and JF43 presented a score of 0 in 24 h, meaning total absence of movement, whereas no eggs and soft tissue damage were observed under optical microscopy. Through scanning electron microscopy, integumentary alterations caused by the compounds JF31 and JF43 were observed, such as: exposure of the musculature, formation of integumentary bubbles, integuments with abnormal morphology and destruction of tubercles and spikes. The results shoerd that the compound JF31 was 2.39 times more selective for adult worms and JF43 was 3.74 times more selective for juvenile worms. Thus, the compounds JF43 and JF31 are the most promising for presenting schistosomicidal activity of S. mansoni.

The COVID-19 and TB syndemic: the way forward

Together, SARS-CoV-2 and M. tuberculosis have killed approximately 5.7 million people worldwide over the past 2 years. The COVID-19 pandemic, and the non-pharmaceutical interventions to mitigate COVID-19 transmission (including social distancing regulations, partial lockdowns and quarantines), have disrupted healthcare services and led to a reallocation of resources to COVID-19 care. There has also been a tragic loss of healthcare workers who succumbed to the disease. This has had consequences for TB services, and the fear of contracting COVID-19 may also have contributed to reduced access to TB services. Altogether, this is projected to have resulted in a 5-year setback in terms of mortality from TB and a 9-year setback in terms of TB detection. In addition, past and present TB disease has been reported to increase both COVID-19 fatality and incidence. Similarly, COVID-19 may adversely affect TB outcomes. From a more positive perspective, the pandemic has also created opportunities to improve TB care. In this review, we highlight similarities and differences between these two infectious diseases, describe gaps in our knowledge and discuss solutions and priorities for future research.

The nanotoxicity assessment of cube-like iron nitride magnetic nanoparticles at the organismal level of nematode Caenorhabditis elegans

Magnetic nanoparticles (NPs) are suitable candidates for various medical and biological applications, despite some concerns that they may have negative impacts on human health. In this study, the toxicity effects of magnetic NPs consisting of α"-Fe₁₆N₂ captured and bioaccumulated by the nematode Caenorhabditis elegans (C. elegans) in the early larval stage are evaluated. The choice of α"-Fe₁₆N₂ NPs is based on their good structural stability when stored in saline solution and high magnetic performance. The uptake and bioaccumulation of α"-Fe₁₆N₂ NPs in intestinal cells of C. elegans was evidenced by transmission electron microscopy. After exposure to NPs up to 40 mg mL^-1, C. elegans larval development, survival, feeding behavior, defecation cycles, movement and reproduction were monitored. C. elegans survival and other monitored behavioral evolutions do not show significant changes, except for a slight statistical reduction in the reproductive profile. Therefore, the present results are promising and very encouraging for investigations of applications of α"-Fe₁₆N₂ NPs in the biomedical area.

Myracrodruon urundeuva leaf lectin damages exochorionic cells and binds to the serosal cuticle of Aedes aegypti eggs

In recent years, lectins have been identified as alternative agents against Aedes aegypti during the aquatic phases of its life cycle. For example, chitin-binding lectin from Myracrodruon urundeuva leaf (MuLL) can function as a larvicide. In this study, we investigated whether MuLL can also act as an ovicide against this insect. Aedes aegypti eggs were incubated with MuLL for 72 h to determine the concentration at which the hatching rate reduces by 50% (EC₅₀). The effects of MuLL on the egg surface structure were evaluated using scanning electron microscopy (SEM), and the possible interaction of MuLL with the internal structures of eggs and embryos was investigated using MuLL-fluorescein isothiocyanate (FITC) conjugate. MuLL acted as an ovicidal agent with an EC₅₀ of 0.88 mg/mL. The SEM analysis revealed that eggs treated with MuLL for 24 and 48 h no longer had tubercles and did not show a well-defined exochorionic network. In addition, deformation and degeneration of the surface were observed after 72 h. Fluorescence microscopy showed that MuLL penetrated the eggs 48 h after incubation and was detected in the upper portion of the embryo's gut. After 72 h, MuLL was observed in the serosal cuticle and digestive tract. In conclusion, MuLL can function as an ovicidal agent against A. aegypti through damage to the surface and internal structures of the eggs.

The Influence of Cement Removal Techniques on In Situ Bacterial Adhesion and Biodegradation at the Marginal Interface of Ceramic Laminates

Objectives

This in situ study aimed to analyze the influence of different resin cement removal techniques on bacterial adhesion and biodegradation at the marginal interface of ceramic laminates.

Methods and Materials

Eighty feldspathic ceramic (F) blocks were prepared and cemented onto bovine enamel slabs (7×2.5×2 mm). Excess cement was removed using a microbrush (MBR), a scalpel blade (SCP), or a Teflon spatula (TSP). For the biodegradation analysis, 40 disc-shaped resin cement specimens were prepared (7×1.5 mm) using a Teflon mold. The specimens were randomly allocated into two groups: (1) No finishing procedure (only Mylar strip), and (2) with finishing and polishing procedures using the Jiffy system (Ultradent, South Jordan, UT, USA) (n=20). The in situ phase consisted of using an intraoral palatal device by 20 volunteers for 7 days. Each device contained five cylindrical wells (8×3 mm), where three dental blocks and two cement specimens were included in the wells. Surface roughness (Ra) was measured using a contact profilometer. A micromorphological analysis was performed under a stereomicroscope and a scanning electron microscope. Bacterial adhesion was quantitated based on the number of colony-forming units (CFU/mL) and their biofilm development potential.

Results

The cement removal techniques directly affected surface roughness at the marginal interface (p<0.001), and the SCP technique produced higher mean roughness, regardless of the surface area analyzed. Surface polishing protected cement specimens from further biodegradation (p=0.148). There were no differences in CFU counts between the groups after the in situ phase (p=0.96). All specimens showed CFU with a strong ability to develop a biofilm.

Conclusions

The techniques used for cement removal increased the surface roughness of ceramic laminates, particularly SCP, but they did not affect bacterial adhesion at the marginal interface. Surface polishing of the resin cement is recommended to mitigate biodegradation.

Toxic effects of thallium acetate by acute exposure to the nematode C. elegans

BACKGROUND

Thallium (Tl) is a toxic metalloid and an emerging pollutant due to electronic devices and dispersal nearby base-metal mining. Therefore, Tl poses a threat to human health and especially the long-term impact on younger individuals exposed is still unknown. This study aimed to evaluate the toxic effects of thallium acetate in C. elegans in early larval stages, considering physiological and behavioral endpoints, as well as the Tl absorption and bioaccumulation.

METHODS

Caenorhabditis elegans (C. elegans) was exposed to Thallium acetate (50, 100, 150, 200, 250, 500, and 1000 μM) in the L1 larval stage, with the purpose to observe the toxic effects invoked until adulthood. Transgenic worms strains were transported GFP, reporters to DAF-16 and were used to verify the antioxidant response. ICP-MS quantified total Tl⁺ concentration to evidence Tl uptake and bioaccumulation.

RESULTS

Thallium acetate caused a significant reduction in the number of living worms (p < 0.0001 in 100-1000 μM), a delay in larval development (p < 0.01; p < 0.001 and p < 0.0001 in 100-1000 μM) through the larval stages, and egg production in the worm's uterus was reduced. Thallium acetate also induced behavioral changes. Additionally, thallium acetate activated antioxidant pathway responses in C. elegans by translocating the DAF-16 transcription factor and activation of SOD-3::GFP expression. The Tl⁺ quantification in worms showed its absorption in the L1 larval stage and bioaccumulation in the body after development.

CONCLUSIONS

Thallium acetate reduced survival, delayed development, caused behavioral changes, induced responses inherent to oxidative stress, and serious damage to the worm's reproduction. In addition, C. elegans absorbed and bioaccumulated Tl⁺. Together, our results highlight the impacts of Tl⁺ exposure in the early stages of life, even for a short period.

Lignin from Morinda citrifolia leaves: Physical and chemical characterization, in vitro evaluation of antioxidant, cytotoxic, antiparasitic and ultrastructural activities

In this work, we investigated in vitro the antioxidant, cytotoxic and anti-leishmanial activities of a lignin extracted from the leaves of Morinda citrifolia. Initially, an analysis of the composition of the sheets was performed, then the lignin was obtained by alkaline delignification and characterized by different techniques: elemental analysis, FT-R, UV-vis, HSQC-NMR, thermal analysis, Py-GC/MS and by GPC. The results showed that the leaves had in their composition cellulose (31.29%), hemicellulose (25.01%), lignin (18.34%), extractives (14.39%) and ash (10.03%). The lignin extraction yield was 89.8%. The lignin obtained is of the GSH type with the following contents 79.39%, 13.58% and 7.03% respectively. Furthermore, it is low molecular weight and thermally stable. It had a phenolic content of 93.3 mg GAE/g and low antioxidant activity. In macrophage cytotoxicity assays, it presented a CC₅₀ of 31.0 μg/mL, showing less toxicity than amphotericin B. In assays against the promastigote forms of Leishmania amazonensis, lignin presented an IC₅₀ of 29.56 μg/mL, a less effective concentration than amphotericin B (IC₅₀ = 0.14 μg/mL). However, it was able to promote inhibition of the parasites, a fact confirmed by structural changes. These findings reinforce that M. citrifolia lignin is a promising macromolecule for use as an antiparasitic and antioxidant agent.

A proteomics evaluation of the primary and secondary immune response of Biomphalaria straminea challenged by Schistosoma mansoni

Biomphalaria spp. snails are intermediary hosts of Schistosoma mansoni, etiologic agent of intestinal schistosomiasis, one of the most important neglected tropical diseases. Biomphalaria straminea is an important intermediary host that possess a different phenotype to parasite infection but shows a large geographic distribution and high capacity of new ecologic niche invasion. Our purpose was to characterize for the first time the differentially expressed proteome in B. straminea during two times intervals after primary and secondary exposure to S. mansoni. The hemolymph was collected at 1 and 15 days after primary and secondary exposure of snails to the parasite. Total proteins were extracted and digested with trypsin. LC-MS/MS label-free quantification was performed and analyzed using Maxquant and Perseus software. Proteins were identified and annotated using Blast2GO tools. After 1 day of exposure, most of upregulated proteins are hemoglobin type 2, C and H type lectins, molecules related to cell adhesion, and response to oxidative stress. After 15 days, we found a similar pattern of upregulated proteins but some fibrinogen-related proteins (FREPs) and TEPs homologs were downregulated. Regarding the differentially expressed proteins during secondary response, the principal immune-related proteins upregulated were C and H type lectins, cellular adhesion molecules, biomphalysin, and FREP3. We noted a several upregulated biological processes during both responses that could be the one of the key points of efficacy in the immune response to parasite. Our data suggests different immune mechanisms used by B. straminea snails challenged with S. mansoni.

Detection of Leishmania infantum amastigotes in neutrophil from peripheral blood in a naturally infected dog

Canine visceral leishmaniasis (CVL) is a zoonotic disease of high lethality caused by Leishmania infantum in the Americas. In the infected dog, the amastigotes are scarce in blood, especially in the late phase of the disease. This study aimed to report a rare case of L. infantum amastigotes found in neutrophils from peripheral blood of a naturally infected dog in terminal phase of CVL, also describing its clinical status before and after treatment with miltefosine 2%. The dog, which presented as polysymptomatic and with classical signs and symptoms of CVL was submitted to the following tests: Dual Path Platform (DPP) rapid test, ELISA and parasitological examination of peripheral blood. Hematological and biochemical parameters were obtained before and after treatment. All diagnostic tests were positive for CVL. The identification of L. infantum amastigotes inside neutrophils from peripheral blood was confirmed through microscopy, and the species was confirmed by molecular analysis. At the end of the treatment, peripheral parasitemia was not detected, and improvements were observed in clinical and laboratorial parameters. Finally, this atypical finding can be used as example to raise discussions about the real immunological role of neutrophils in late phases of CVL and its clinical/therapeutic implications.

American visceral leishmaniasis in a state of northeastern Brazil: clinical, epidemiological and laboratory aspects

In Brazil, American visceral leishmaniasis (AVL) has become a public health concern due to its high incidence and lethality. This study aimed to analyze the clinical, epidemiological, and laboratory aspects of AVL in a state of Brazil. This descriptive, cross-sectional, retrospective, and quantitative study of notified cases of AVL was carried out in Alagoas between 2008 and 2017 from data obtained from DATASUS/SINAN. Sociodemographic, clinical, and laboratory variables were analyzed. A descriptive analysis was performed using absolute values ​​and valid percentages, using tables and/or graphs. Data processing was performed using Stata 12.0®. Results with P <0.05 were considered statistically significant. During the study period, 352 cases of AVL were reported, of which 6.82% died and 38.92% had met a cure criterion. Male patients were predominant (66.76%). Of the total infected patients, 16.76% had attended only the 1st to the 4th grades, with those most affected aged 1 to 4 years (28.69%). Laboratory diagnostic criteria were most commonly used to confirm the notified cases (76.42%), whereas 51.70% and 8.52% of the cases had positive parasitological and immunofluorescence diagnoses, respectively. Finally, the study showed a higher prevalence of the disease in children, men and in rural residents. Although with low lethality, the expressive frequency of AVL in the State of Alagoas was still verified, since there was an increase in the number of cases during the years of the study.

A first, naturally occurring substitution at the second pyrethroid receptor of voltage-gated sodium channel of Aedes aegypti

BACKGROUND

Aedes aegypti is a remarkably effective mosquito vector of epidemiologically important arboviral diseases including dengue fever, yellow fever and Zika. The present spread of resistance against pyrethroids, the primary insecticides used for mosquito control, in global populations of this species is of great concern. The voltage-gated sodium channel (VGSC) in the nervous system is the known target site of pyrethroids in insects. Past studies have revealed several amino-acid substitutions in this channel that confer pyrethroid resistance, which are known as knockdown resistance (kdr) mutations.

RESULTS

This study investigated a laboratory colony of Ae. aegypti, MCNaeg, established from larvae collected in Rio de Janeiro, Brazil in 2016. The MCNaeg colony showed strong resistance against pyrethroids without laboratory selection. Of the two VGSC gene haplotypes present within this colony, one harbored three known kdr mutations, V410L, V1016I, and F1534C, and the other harbored only the known F1534C mutation. In latter haplotype, we also found novel amino-acid substations including V253F. Previous molecular modeling and electrophysiological studies suggest that this residue serves a pyrethroid-sensing site in the second receptor, PyR2. Our genetical analysis showed that the haplotype harboring V253F and F1534C is associated with equal or slightly stronger resistance than the other triple kdr haplotype to both Type I and Type II pyrethroids.

CONCLUSION

The novel substitution V253F is potentially involved in pyrethroid resistance in Ae. aegypti. Further studies are needed to elucidate the role of this substitution in the pyrethroid susceptibility of VGSC. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Aspects related to positivity for schistosomiasis: a cross-sectional study in a low prevalence area in Alagoas, Brazil, 2020

OBJECTIVE

To analyze aspects related to schistosomiasis positivity in an area of low prevalence in Brazil.

METHODS

This was a cross-sectional study, carried out in the first half of 2020, where we analyzed the proportion of positivity, according to the number of Kato-Katz slides, the diagnostic performance of the test and positivity estimates based on data from the Schistosomiasis Surveillance and Control Program Information System (SISPCE).

RESULTS

2,088 slides from 348 individuals were analyzed, with proportion of positivity of 11.8%, 26.7% and 31.0% for 1, 4 and 6 slides analyzed, respectively. There was excellent agreement (Kappa = 0.91) between the readings of 4 and 6 slides. The SISPCE data was estimated to be underreported by up to 2.1 times.

CONCLUSION

Increasing the number of slides increased Kato-Katz positivity, which can contribute to maximizing the control of the disease as a Public Health problem.

Structural design, synthesis and anti-Trypanosoma cruzi profile of the second generation of 4-thiazolidinones chlorine derivatives

Chagas disease causes more deaths in the Americas than any other parasitic disease. Initially confined to the American continent, it is increasingly becoming a global health problem. In fact, it is considered to be an "exotic" disease in Europe, being virtually undiagnosed. Benznidazole, the only drug approved for treatment, effectively treats acute-stage Chagas disease, but its effectiveness for treating indeterminate and chronic stages remains uncertain. Previously, our research group demonstrated that 4-thiazolidinones presented anti-T. cruzi activity including in the in vivo assays in mice, making this fragment appealing for drug development. The present work reports the synthesis and anti-T. cruzi activities of a novel series of 4-thiazolidinones derivatives that resulted in an increased anti-T. cruzi activity in comparison to thiosemicarbazones intermediates. Compounds 2c, 2e, and 3a showed potent inhibition of the trypomastigote form of the parasite at low cytotoxicity concentrations in mouse splenocytes. Besides, all the 2c, 2e, and 3a tested concentrations showed no cytotoxic activity on macrophages cell viability. When macrophages were submitted to T. cruzi infection and treated with 2c and 3a, compounds reduced the release of trypomastigote forms. Results also showed that the increased trypanocidal activity induced by 2c and 3a is independent of nitric oxide release. Flow cytometry assay showed that compound 2e was able to induce necrosis and apoptosis in trypomastigotes. Parasites treated with the compounds 2e, 3a, and 3c presented flagellum shortening, retraction and curvature of the parasite body, and extravasation of the internal content. Together, these data revealed a novel series of 4-thiazolidinones fragment-based compounds with potential effects against T. cruzi and lead-like characteristics.

Splenic Nodules: Canine Visceral leishmaniasis?

Background: Canine visceral leishmaniasis (CVL) is a parasitic disease of high lethality caused by the protozoan Leishmania infantum in Brazil and is often related to splenomegaly. However, splenic nodules in dogs, although frequent, have not previously been reported as associated with CVL, but with neoplastic diseases. Considering that most dogs infected are oligosymptomatic or asymptomatic and that splenic nodules are common to other diseases, it is prudent to differentially diagnose CVL in view of its high zoonotic potential and lethality. The objective of the study was to describe a case of splenomegaly with splenic nodules associated with CVL in an asymptomatic dog treated with 2% miltefosina.                                             Case: A 5-year-old male Rottweiler with 41 kg, with a history of inappetence, apathy and weight loss was referred to the Veterinary Medicine School Clinic of the Cesmac University Center, Maceió, AL, Brazil. However, during palpation a slight increase in the spleen was noted. Hematological, hemoparasite, biochemical and abdominal ultrasonographic examinations were requested to clarify the clinical suspicion of hemoparasitosis. The hematological and biochemical results respectively showed the following: normocytic normochromic anemia, hyperproteinemia and thrombocytopenia, in addition to hypoalbuminemia, with elevated total protein levels. The test for hemoparasites was negative. Ultrasonography showed mixed echogenicity suggestive of nodules. The rapid test for Ehrlichia, Anaplasma and L. infantum was performed. It was positive only for L. infantum. ELISA, IFAT and qPCR tests were performed to confirm the result. The test showed a cut-off result of 0.371 for ELISA, positive for RIFI at a cut-off of 1:40 and qPCR with less than 1 fg and with amplification above 36 cycles. In view of these results, treatment with 2% miltefosine at a dose of 1 mL/ 10 kg was started once a day, after feeding, for 28 days. The animal was monitored throughout treatment and re-evaluated every 10 days for 30 days, showing signs of clinical development, presenting satisfactory results.Discussion: Canine splenomegaly can be associated with a variety of disease possibilities. In asymptomatic canine visceral leishmaniasis (CanL), the slight increase in spleen and the presence of splenic nodules may lead to a false diagnosis. Splenic nodules may be associated with dogs of advanced age and may be due to lymphoid nodular hyperplasia, which causes nodules with echogenicity, hyperechoic regions with well demarcated irregularity, with centralized hypoechoic areas and an absence of hematological and biochemical alterations. The cause of splenomegaly associated with nodules may be difficult to diagnose and require much time and effort. Therefore, diseases such as visceral leishmaniasis of high lethality must be the priority in differential diagnosis in endemic areas in order to minimize the risk of transmission. In addition to allowing an early intervention aiming at good animal health results and preventive measures, such as the use of repellent collars that reduce the risk of phlebotomo infection. The differential diagnosis of CVL is necessary in endemic areas, even in asymptomatic dogs that may present splenic alterations suggestive of other diseases. Treatment with 2% miltefosine was shown to be, in this case, effective at reducing the splenic nodules and a good alternative for the quality of life of the animal.

An integrated approach to control Cystic Echinococcosis in southern Italy

Cystic echinococcosis (CE) is a severe zoonosis, caused by the larval stage of the tapeworm Echinococcus granulosus. This helminth infection is of increasing public health and socio-economic concern due to the considerable morbidity rates that cause economic losses both in the public health sector and in the livestock industry. Control programmes against E. granulosus are considered long-term actions which require an integrated approach and high expenditure of time and financial resources. Since 2010, an integrated approach to control CE has been implemented in a highly endemic area of continental southern Italy (Campania region). Innovative procedures and tools have been developed and exploited during the control programme based on the following strategies: i) active and passive surveillance in livestock (using geospatial tools for georeferencing), ii) diagnosis in dogs (using the FLOTAC techniques and molecular analysis), iii) targeted treatment of farm dogs (using purpose-built confinement cages), iv) early diagnosis in livestock (by ultrasonography), v) surveillance in humans (through hospital discharge records analysis), vi) monitoring the food chain (analysing raw vegetables), vii) outreach activities to the general public (through dissemination material, e.g. brochures, gadgets, videos, virtual reality). Over eight years, the integrated approach and the new strategies developed have resulted in a noteworthy reduction of the parasite infection rates in livestock (e.g. up to 30 % in sheep). The results obtained so far highlight that using a one health multidisciplinary and multi-institution effort is of pivotal importance in preparing CE control programmes at regional level and could be extended to other endemic Mediterranean areas.

Antibacterial effects of the lectin from pomegranate sarcotesta (PgTeL) against Listeria monocytogenes

AIMS

To investigate the effects of the lectin from Punica granatum sarcotesta (PgTeL) on growth, viability, cell structure, biofilm formation and chitinase activity of Listeria monocytogenes. In addition, the effect of PgTeL on the adhesion and invasion of human cells (HeLa) was determined.

METHODS AND RESULTS

PgTeL showed bacteriostatic and bactericidal effects on the strains L. monocytogenes N53-1 and EGD-e, causing morphometric alterations, cell aggregation, strong deformation and cell disruption. PgTeL inhibited biofilm formation by EGD-e and N53-1 and also interfered with the adhesion and invasion processes of EGD-e and N53-1 in HeLa cells. Finally, the chitinase activity of L. monocytogenes EGD-e was reduced in the presence of PgTeL, which can be involved in the inhibition of adhesion process.

CONCLUSION

PgTeL is an antibacterial agent against L. monocytogenes, inhibiting growth and promoting cell death, as well as impairing biofilm formation and bacterial adhesion and invasion into human cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results stimulate future investigations on the potential of PgTeL for protection of contamination in food products.

The design, synthesis, and in vitro trypanocidal and leishmanicidal activities of 1,3-thiazole and 4-thiazolidinone ester derivatives

Chagas and leishmaniasis are both neglected tropical diseases, whose inefficient therapies have made them remain the cause for millions of deaths worldwide. Given this, we synthesized 27 novel 1,3-thiazoles and 4-thiazolidinones using bioisosteric and esterification strategies to develop improved and safer drug candidates. After an easy, rapid and low-cost synthesis with satisfactory yields, compounds were structurally characterized. Then, in vitro assays were performed, against Leishmania infantum and Leishmania amazonensis promastigotes, Trypanosoma cruzi trypomastigotes and amastigotes, for selected compounds to determine IC₅₀ and SI, with cytotoxicity on LLC-MK2 cell lines. Overall, 1,3-thiazoles exhibited better trypanocidal activity than 4-thiazolidinones. The compound 1f, an ortho-bromobenzylidene-substituted 1,3-thiazole (IC₅₀ = 0.83 μM), is the most potent of them all. In addition, compounds had negligible cytotoxicity in mammalian cells (CC₅₀ values > 50 μM). Also noteworthy is the examination of the cell death mechanism of T. cruzi, which showed that compound 1f induced necrosis and apoptosis in the parasite. Scanning electron microscopy analysis demonstrated that the treatment of Trypanosoma cruzi trypomastigote cells with the compound 1f at different IC₅₀ concentrations promoted alterations in the shape, flagella and body surface, inducing parasite death. Together, our data revealed a novel series of 1,3-thiazole structure-based compounds with promising activity against Trypanosoma cruzi and Leishmania spp., broadening ways for scaffold optimization.

Chagas and leishmaniasis are both neglected tropical diseases, whose inefficient therapies have made them remain the cause for millions of deaths worldwide.

In vitro and in vivo evaluation of dialkylphosphorylhydrazones against Leishmania chagasi promastigotes and amastigotes

In our study, two new dialkylphosphorylhydrazones have been designed targeting activity against L. braziliensis and L. amazonensis parasites, and their mechanism of action, as well as their leishmanicidal activity against L. chagasi, was evaluated.

Dual Parasiticidal Activities of Phthalimides: Synthesis and Biological Profile against Trypanosoma cruzi and Plasmodium falciparum

Chagas disease and malaria are two neglected tropical diseases (NTDs) that prevail in tropical and subtropical regions in 149 countries. Chagas is also present in Europe, the US and Australia due to immigration of asymptomatic infected individuals. In the absence of an effective vaccine, the control of both diseases relies on chemotherapy. However, the emergence of parasite drug resistance is rendering currently available drugs obsolete. Hence, it is crucial to develop new molecules. Phthalimides, thiosemicarbazones, and 1,3-thiazoles have been used as scaffolds to obtain antiplasmodial and anti-Trypanosoma cruzi agents. Herein we present the synthesis of 24 phthalimido-thiosemicarbazones (3 a-x) and 14 phthalimido-thiazoles (4 a-n) and the corresponding biological activity against T. cruzi, Plasmodium falciparum, and cytotoxicity against mammalian cell lines. Some of these compounds showed potent inhibition of T. cruzi at low cytotoxic concentrations in RAW 264.7 cells. The most active compounds, 3 t (IC₅₀ =3.60 μM), 3 h (IC₅₀ =3.75 μM), and 4 j (IC₅₀ =4.48 μM), were more active than the control drug benznidazole (IC₅₀ =14.6 μM). Overall, the phthalimido-thiosemicarbazone derivatives were more potent than phthalimido-thiazole derivatives against T. cruzi. Flow cytometry assay data showed that compound 4 j was able to induce necrosis and apoptosis in trypomastigotes. Analysis by scanning electron microscopy showed that T. cruzi trypomastigote cells treated with compounds 3 h, 3 t, and 4 j at IC₅₀ concentrations promoted changes in the shape, flagella, and surface of the parasite body similar to those observed in benznidazole-treated cells. The compounds with the highest antimalarial activity were the phthalimido-thiazoles 4 l (IC₅₀ =1.2 μM), 4 m (IC₅₀ =1.7 μM), and 4 n (IC₅₀ =2.4 μM). Together, these data revealed that phthalimido derivatives possess a dual antiparasitic profile with potential effects against T. cruzi and lead-like characteristics.

New epidemiological profile of schistosomiasis from an area of low prevalence in Brazil

INTRODUCTION

Schistosomiasis, caused by infection from Schistosoma mansoni, is a disease that represents an important public health problem for Brazil, especially for states in the Northeast region. Thus, the aim of this study is to present a new epidemiological profile for the disease in a municipality with low prevalence in the state of Alagoas, Brazil.

METHODS

A cross-sectional study was conducted through a coproparasitological and malacological survey. A structured questionnaire was applied to the study participants to survey possible risk factors and a spatial analysis (kernel density) was used to measure the risk of infection.

RESULTS

Of the 347 participants, 106 (30.5%) were infected by Schistosoma mansoni, most of them from the urban area of the municipality (68.9%; 73/106). A 3-fold risk of infection was found for individuals living in the urban area and a risk of 2.15 times for self-declared farmers. Biomphalaria glabrata and B. straminea were the species found in the municipality, but no animals were diagnosed as infected by the parasite. Spatial analysis showed a random distribution of vectors and human cases of the disease, and the formation of two clusters of human cases in the urban area was seen.

CONCLUSIONS

A new epidemiological profile for schistosomiasis from S. mansoni infection was presented in a municipality of low endemicity: a high proportion of positive individuals in the urban area; presence of snails without positive diagnosis for S. mansoni infection; random distribution of vectors and human cases; and absence of association between classical risk factors and human infection.

Antimicrobial activity and biofilm inhibition of riparins I, II and III and ultrastructural changes in multidrug-resistant bacteria of medical importance

Natural products have been used to treat various infections; however, the development of antimicrobials has made natural products in disuse. Riparin I, II and III are natural alkamide isolated from Aniba riparia (Ness) Mez (Lauraceae), that exhibit economic importance and it is used in traditional medicine, and popularly known as "louro". This study investigated the cytotoxicity, antimicrobial and antibiofilm activity, and ultrastructural changes in vitro by riparins I, II and III in Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa. We analyzed the cytotoxicity by MTT assay in Vero cells and hemolytic action verified in human erythrocytes. The antimicrobial activity was determined by microdilution in broth against ATCC strains, identifying the susceptible species. Subsequently, only the MDR isolates of sensitive bacterial species were evaluated regarding its biofilm formation and ultrastructural changes. Riparin I presented low cytotoxicity and hemolytic percentage ranging from of 9.01%-12.97%. Only the riparin III that showed antimicrobial activity against MDR clinical isolates, and significant reduction in biofilm formation in S. aureus. Moreover, the riparin III promoted ultrastructural changes in bacterial cells, such as elongated cellular without bacterial septum, cells with a rugged appearance on the cell surface and cytoplasmic material extravasation. As has been noted riparin III has an inhibitory potential against biofilm formation in S. aureus, besides having antimicrobial activity and promoting ultrastructural changes in MDR clinical isolates. Thus, riparin III is an interesting alternative for further studies aiming to develop new therapeutic options.

Production and partial purification by PEG/citrate ATPS of a β-galactosidase from the new promising isolate Cladosporium tenuissimum URM 7803

β-Galactosidase production, partial purification and characterization by a new fungal were investigated. Partial purification was performed by aqueous two-phase system (ATPS) using polyethylene glycol (PEG) molar mass, PEG concentration, citrate concentration and pH as the independent variables. Purification factor (PF), partition coefficient (K) and yield (Y) were the responses. After identification by rDNA sequencing and classification as Cladosporium tenuissimum URM 7803, this isolate achieved a maximum cell concentration and β-galactosidase activity of 0.48 g/L and 462.1 U/mL, respectively. β-Galactosidase partitioned preferentially for bottom salt-rich phase likely due to hydrophobicity and volume exclusion effect caused in the top phase by the high PEG concentration and molar mass. The highest value of PF (12.94) was obtained using 24% (w/w) PEG 8000 g/mol and 15% (w/w) citrate, while that of Y (79.76%) using 20% (w/w) PEG 400 g/mol and 25% (w/w) citrate, both at pH 6. The enzyme exhibited optimum temperature in crude and ATPS extracts in the ranges 35-50 °C and 40-55 °C, respectively, and optimum pH in the range 3.0-4.5, with a fall of enzyme activity under alkaline conditions. Some metal ions and detergents inhibited, while others stimulated enzyme activity. Finally, C. tenuissimum URM 7803 β-galactosidase showed a profile suitable for prebiotics production.

Analysis and spatial distribution of schistosomiasis mansoni in a historically endemic area of northeastern Brazil

OBJECTIVE

To perform a descriptive analysis of the activities of the Schistosomiasis Control Program, as well as the spatial distribution of the condition in the state of Alagoas, Brazil, for the period from 2007 to 2016.

METHODS

Descriptive ecological study. Data from positive human cases and operational data were collected in the Information System of the Schistosomiasis Control Program, and data for spatial analysis were collected on the website of the Brazilian Institute of Geography and Statistics. An analysis of spatial autocorrelation (Moran statistics) was performed, where a spatial pattern was established, which showed the Q1 and Q2 patterns to be the most important, and Q3 and Q4 representing transition areas.

RESULTS

In the years under study, at least 85% (n = 60/70) of the municipalities carried out the activities recommended by the PCE (Schistosomiasis Control Program). Alagoas presented an average positivity rate of 7.1%, which is very high compared to the prevalence of 3.3% at the last national schistosomiasis survey conducted between 2010 and 2015. Moran's statistics showed 22/70 municipalities forming a Q1 cluster, of high/high pattern, and 32/70 municipalities forming a Q2 cluster, of low/low pattern, with the others in a transition area. Moran Map data, however, showed only 7/70 municipalities in the endemic area with a spatial autocorrelation, with these municipalities having the Mundau River as a common element.

CONCLUSION

Schistosomiasis mansoni is of great importance for public health in Alagoas and that the use of spatial analysis can identify priority areas for preventive and control measures against schistosomiasis mansoni.

First detection of a Vssc allele V1016G conferring a high level of insecticide resistance in Aedes albopictus collected from Europe (Italy) and Asia (Vietnam), 2016: a new emerging threat to controlling arboviral diseases

Introduction

Aedes albopictus (Skuse) is an important vector of arboviral diseases, including dengue, chikungunya and Zika virus disease. Monitoring insecticide resistance and mechanisms by which the mosquito develops resistance is crucial to minimise disease transmission.

Aim

To determine insecticide resistance status and mechanisms in Ae. albopictus from different geographical regions.

Methods

We sampled 33 populations of Ae. albopictus from Asia, Europe and South America, and tested these for susceptibility to permethrin, a pyrethroid insecticide. In resistant populations, the target site for pyrethroids, a voltage-sensitive sodium channel (Vssc) was genotyped. Three resistant sub-strains, each harbouring a resistance allele homozygously, were established and susceptibilities to three different pyrethroids (with and without a cytochrome P450 inhibitor) were assayed.

Results

Most populations of Ae. albopictus tested were highly susceptible to permethrin but a few from Italy and Vietnam (4/33), exhibited high-level resistance. Genotyping studies detected a knockdown resistance (kdr) allele V1016G in Vssc for the first time in Ae. albopictus. Two previously reported kdr alleles, F1534C and F1534S, were also detected. The bioassays indicated that the strain homozygous for the V1016G allele showed much greater levels of pyrethroid resistance than other strains harbouring F1534C or F1534S.

Conclusion

The V1016G allele was detected in bothAsian and Italian Ae. albopictus populations, thus a spread of this allele beyond Italy in Europe cannot be ruled out. This study emphasises the necessity to frequently and regularly monitor the V1016G allele in Ae. albopictus, particularly where this mosquito species is the main vector of arboviruses.

Anti-biofilm effect by the combined action of fluconazole and acetylsalicylic acid against species of Candida parapsilosis complex

The Candida parapsilosis complex has been associated with highly refractory infections mainly due to the presence of biofilms. High glucose levels enable the development of this virulence factor which can aggravate the clinical condition of patients with diabetes mellitus, those using parenteral nutrition, with invasive medical device, including others. Combined antifungal therapy, such as azole and cyclooxygenase inhibitors, may be an alternative in such infections since they modulate prostaglandin production favoring the adhesion and development of biofilms. Thus, the present study aimed to evaluate the influence of glucose supplementation in the formation and detection of Candida parapsilosis complex biofilms and to treat them using fluconazole and a cyclooxygenase inhibitor in combination. Protein spectra evaluation allowed the differentiation between species from the complex (score > 2) in our studies. All isolates were able to form active biofilms at different glucose concentrations. In addition, a significant reduction in biofilm formation was observed when fluconazole and acetylsalicylic acid were combined. The ultrastructural analysis presented typical biofilm characteristics by species from the complex. These data support new combined therapies for the treatment of fungal infections, especially with those which are resistant and therapeutic failure is associated with virulence factors.

Thiophene-thiosemicarbazone derivative (L10) exerts antifungal activity mediated by oxidative stress and apoptosis in C. albicans

Reactive oxygen species (ROS) cause cell damage and death. To reverse these effects, cells produce substances such as reduced glutathione (GSH) that serve as substrates for antioxidant enzymes. One way to combat microbial resistance includes nullifying the effect of glutathione in microbial cells, causing them to die from oxidative stress. The compound 2-((5-nitrothiophen-2-yl)methylene)-N-(pyridin-3-yl) hydrazine carbothioamide (L10) is a new thiophene-thiosemicarbazone derivative with promising antifungal activity. The aim of this study was to evaluate its mechanism of action against Candida albicans using assays that evaluate its effects on redox balance. Treatment with L10 promoted significant changes in the minimum inhibitory concentration (MIC) values in ascorbic acid and GSH protection tests, the latter increasing up to 64-fold of the MIC. Using nuclear magnetic resonance, we demonstrated interaction of L10 and GSH. At concentrations of 4.0 and 8.0 μg/mL, significant changes were observed in ROS production and mitochondrial membrane potential. The cell death profile showed characteristics of initial apoptosis at inhibitory concentrations (4.0 μg/mL). Transmission electron microscopy data corroborated these results and indicated signs of apoptosis, damage to plasma and nuclear membranes, and to mitochondria. Taken together, these results suggest a possible mechanism of action for L10 antifungal activity, involving changes in cellular redox balance, ROS production, and apoptosis-compatible cellular changes.

Use of MALDI-TOF MS to identify the culturable midgut microbiota of laboratory and wild mosquitoes

Mosquitoes are responsible for transmitting many pathogens to humans and Aedes aegypti, Aedes albopictus and Culex quinquefasciatus are important vectors in the world. The microbiota plays an important role in developmental studies that involve impacts on the biological cycle of mosquitoes and vector control strategies. In this study, the aim was to understand the environment plays in the microbiota culturable diversity of Aedes aegytpi, Aedes albopictus and Culex quinquefasciatus. Midgut of studied mosquitoes (laboratory-reared and wild) were dissected and analyzed by MALDI-TOF MS to identify the microbiota. Most of the bacteria identified in the microbiota of mosquitoes from the laboratory and field belong to the phylum Proteobacteria. We reported on the microbial diversity among the mosquito species studied where Cx. quinquefasciatus and Ae. albopictus show greater bacterial similarity. The genus Rahnella was present in all mosquito species studied, both in those from the laboratory and those from the wild. Bacillus, Ewingella, Microccocus, Klebsiella and Pantoea are genera was predominant among the mosquitoes studied. The difference of microbiota diversity between mosquitoes laboratory-reared and wild shows that the environment plays an important role in the acquisition of bacteria, mainly in Ae. aegypti and Cx. quinquefasciatus.

In vivo effect of essential oil of Mentha x villosa and its active compound against Schistosoma mansoni (Sambon, 1907)

Schistosomiasis treatment is dependent on a single drug, praziquantel (PZQ). The development of resistance of PZQ has drawn the attention of many researchers to alternative drugs. One viable and promising treatment is the study of medicinal plants as a new approach to the experimental treatment for Schistosomiasis. The present work aimed to evaluate in vivo antischistosomal activity of effect of Mentha x villosa Oil Essential (Mv-EO) and rotundifolone (ROT) against Schistosoma mansoni. Thirty-day-old female Swiss webster mice (Mus musculus) weighing 50 grams were used. Mice were infected with 80 cercariae of S. mansoni (BH strain) and orally administered Mv-EO (50, 100 and 200 mg/Kg) and ROT (35.9, 70.9 and 141.9 mg/Kg) at 45-days post infection for 5 consecutive days. All mice were euthanized 60 days after infection. Praziquantel was the positive control in the experiment. Doses of 200 mg/kg (Mv-EO) and ROT (141.9 mg/Kg) resulted in a significant reduction in fluke burden (72.44% and 74.48%, respectively). There was also marked reduction in liver, intestinal and faecal and changed oogram pattern, compared to infected untreated mice. Considering the results obtained, further biological studies are required in order to elucidate the mechanism of schistosomicidal action on against adult S. mansoni.

In vitro activity, ultrastructural studies and in silico pharmacokinetic properties of indol-3-yl-thiosemicarbazones derivatives and analogues against juvenile and adult worms of S. mansoni

The present work aimed to carry out in vitro biological assays of indol-3-yl derivatives thiosemicarbazones (2a-e) and 4-thiazolidinones (3a-d) against juvenile and adult worms of S. mansoni, as well as the in silico determination of pharmacokinetic parameters for the prediction of the oral bioavailability of these derivatives. All compounds were initially screened at a concentration of 200 μM against S. mansoni adult worms and the results evidenced the good activity of compounds 2b, 2d and 3b, which caused 100% mortality after 24, 48 and 72 h, respectively. Subsequent studies with these same compounds revealed that compound 2b was able to reduce the viability of the parasites by 85% and 83% at concentrations of 200 and 100 μM, respectively. In relation to the juvenile worms, all compounds (2b, 2d and 3b) were able to cause mortality, but compound 2b demonstrated better activity causing 100% mortality in 48 h. Additionally, it was possible to observe reduction in the viability of juvenile worms of 85%, 81% and 64% at concentrations of 200, 100 and 50 μM, respectively. Several ultrastructural damages were observed when adult and juvenile S. mansoni worms were exposed to compound 2b (200 μM) that was characterized by extensive destruction by the integument, which may justify the mortality rate of cultured parasites. In the DNA interaction assay, fragmentation of the genetic material of adult worms when treated with compound 2b (200 μM) was evidenced, indicating the apoptosis process as mechanism of parasite death. Regarding pharmacokinetic properties, all derivatives are according to the required parameters, predicting good oral bioavailability for the studied compounds. The results presented in this study reveal the good activity of compound 2b in both adult and juvenile worms of S. mansoni, pointing this compound as promising in the development of further studies on schistosomicidal activity.

Phenotypic, structural, and ultrastructural analysis of triple-negative breast cancer cell lines and breast cancer stem cell subpopulation

Triple negative breast cancer (TNBC) is a highly heterogeneous disease, which influences the therapeutic response and makes difficult the discovery of effective targets. This heterogeneity is attributed to the presence of breast cancer stem cells (BCSCs), which determines resistance to chemotherapy and subsequently disease recurrence and metastasis. In this context, this work aimed to evaluate the morphological and phenotypic cellular heterogeneity of two TNBC cell lines cultured in monolayer and tumorsphere (TS) models by fluorescence and electron microscopy and flow cytometry. The BT-549 and Hs 578T analyses demonstrated large phenotypic and morphological heterogeneity between these cell lines, as well as between the cell subpopulations that compose them. BT-549 and Hs 578T are heterogeneous considering the cell surface marker CD44 and CD24 expression, characterizing BCSC mesenchymal-like cells (CD44⁺/CD24^-), epithelial cells (CD44^-/CD24⁺), hybrid cells with mesenchymal and epithelial features (CD44⁺/CD24⁺), and CD44^-/CD24^- cells. BCSC epithelial-like cells (ALDH⁺) were found in BT-549, BT-549 TS, and Hs 578T TS; however, only BT-549 TS showed a high ALDH activity. Ultrastructural characterization showed the heterogeneity within and among BT-549 and Hs 578T in monolayer and TS models being formed by more than one cellular type. Further, the mesenchymal characteristic of these cells is demonstrated by E-cadherin absence and filopodia. It is well known that tumor cell heterogeneity can influence survival, therapy responses, and the rate of tumor growth. Thus, molecular understanding of this heterogeneity is essential for the identification of potential therapeutic options and vulnerabilities of oncological patients.

Punica granatum sarcotesta lectin (PgTeL) has antibacterial activity and synergistic effects with antibiotics against β-lactamase-producing Escherichia coli

The sarcotesta of Punica granatum fruit contains an antimicrobial lectin called PgTeL. In this work, we evaluated the antibacterial activity of PgTeL against five drug-resistant Escherichia coli isolates able to produce β-lactamases. Minimum inhibitory (MIC) and bactericidal (MBC) concentrations were determined by broth dilution. Morphometric and viability analyses were performed by flow cytometry, and ultrastructural changes were evaluated by scanning electron microscopy. Potential synergistic effects of PgTeL with antibiotics and anti-biofilm effect were also evaluated. PgTeL showed antibacterial activity against all isolates with MIC and MBC values ranging from 12.5 to 50.0 μg/mL and from 25.0 to 100.0 μg/mL, respectively. For most isolates, PgTeL postponed the growth start by at least ten hours. At the MIC, the lectin caused alterations in size, shape and structure of bacterial cells. The combination PgTeL-ceftazidime showed a synergistic effect for all isolates. Synergy was also detected with ampicillin (one isolate), carbenicillin (one isolate), cefotaxime (one isolate), cephalexin (four isolates) and cefuroxime (three isolates). PgTeL exhibited anti-biofilm activity against all isolates, causing ≥50% inhibition of biofilms at or above 6.25 μg/mL. The antibacterial effect of PgTeL and its synergy with antibiotics indicate that this fruit-derived molecule may have potential for future treatment of multidrug-resistant infections.

Schistosomicidal and prophylactic activities of phthalimido-thiazoles derivatives on schistosomula and adult worms

Schistosomiasis is a major public health problem worldwide, especially in poor communities. Praziquantel is currently the only drug available to treat schistosomiasis and it shows low efficacy against schistosomula and juveniles stages of Schistosoma mansoni, allowing lower cure rate in areas with high endemicity. There is an urgent need to identify new antischistosomal drugs. Previous works identified phthalimido-thiazoles as privileged structures acting as schistossomicidal agent. In this way, a phthalimido-thiosemicarbazide intermediate and eight phthalimido-thiazoles derivatives were evaluated concerning the in vitro antischistosomal activity compounds in adult phase of Schistosoma mansoni and examined alterations on the tegumental surface. The results revealed that compounds 2f, 2 l and 2 m caused significant mortality in adult worms at concentrations range of 20 μg/mL to 100 μg/mL. These compounds were also selected in view to verify the activity against the schistosomula. Compound 2 m promoted 100% of mortality of larval forms until doses of 2.5 μg/mL within 48 h. In addition, when compound 2 m was administered orally at dose of 200 mg/kg for 5 consecutive days to the infected mouse with adult schistosomes, a reduction in the parasite burden was observed. Furthermore, scanning electron microscopy revealed that compound 2 m kill the parasite by tegumental damage and bubbles generation.

In vitro evaluation of mercury (Hg2+) effects on biofilm formation by clinical and environmental isolates of Klebsiella pneumoniae

The increase in urbanization and industrialization has contributed to the contamination of different environments by means of xenobiotic compounds, such as heavy metals, causing changes in microbial communities. Among these metals, the Mercury (Hg²⁺) is one the most prevalent toxic metals for the environment The present study aimed to evaluate the effect of mercury on the formation of biofilm by environmental (collected from urban stream water) and clinical isolates of Klebsiella pneumoniae. In addition, antibiotic resistance, virulence factors, and genetic diversity were investigated. Taxonomic identity of eight isolates (one reference, two clinical, and five environmental isolates) was performed by MALDI-TOF-MS, while the antibiotic susceptibility profile was assessed by the disc diffusion method. The ability to form biofilms was evaluated by culture on Congo red agar and by crystal violet staining. Biofilm structure was analyzed by scanning electron microscopy. The hydrophobicity profile and the presence of the virulence genes cps, fimH, and mrkD was investigated. The presence of merA and its relationship with antimicrobial resistance were also assessed. The identity of all isolates was confirmed by MALDI-TOF-MS, and different profiles of resistance to mercury and antibiotics as well as of biofilm formation were identified for the clinical and environmental isolates. All isolates were hydrophilic and positive for the virulence genes cps, fimH, and mrkD; only the clinical isolate K36-A2 was positive for merA. The diversity of the isolates was confirmed by ERIC-PCR, which revealed high heterogeneity among the isolates. In conclusion, the data demonstrate that the investigated isolates present different responses to exposure to Hg²⁺ and correspond to distinct populations of K. pneumoniae disseminated in the investigated environment. The data obtained in this work will aid in understanding the mechanisms of survival of this pathogen under adverse conditions.

Social determinants of health associated with topical repellent use in pregnancy: a cross-sectional study during a Zika outbreak in Brazil

Background

Repellent use during pregnancy was strongly recommended after uncovering Zika virus (ZIKV) involvement with congenital malformations. In this context, Pernambuco, Brazil played a key role since it was the epicentre for the main studies suggesting ZIKV teratogenicity and one of Brazil's most affected states during the 2014-2016 epidemics. Thus we aimed to identify possible associations between social determinants of health and repellent use in pregnancy during the ZIKV outbreak in Pernambuco.

Methods

We conducted a cross-sectional study (July-December 2016) with 539 pregnant women residing in Pernambuco and estimated the associations by prevalence ratio and multivariable logistic regression.

Results

Repellents were associated with pregnant women ≥30 y; graduates, employed, health professionals, private health system users and with a monthly income per person greater than two minimum wages. Women whose domiciles favour mosquitoes (ground-floor houses, intermittent water supply from general distribution or water trucks and for ≤6 d/week, cesspools/open wastewater, indoor household water storage) were less likely to use repellents. There was no association for peridomiciles.

Conclusions

Repellents were not associated with ZIKV in most vulnerable pregnant women, despite all the general recommendations made during the Pernambuco epidemic. This study observed a demand for public policies focused on health, education and sanitation problems related to deprived social groups along with their co-responsibility rather than focusing on individual attitudes against mosquitoes.

Evaluation of Serum Biochemical Parameters, Structural Changes, Immunohistochemistry and Parasite Load in the Urinary System of Dogs Infected Naturally by Leishmania infantum

The aim of this study was to evaluate the histopathological changes in the urinary system and their correlation with serum biochemical parameters, parasite load and immunodetection of amastigotes in 30 dogs infected naturally by Leishmania infantum. The major histological changes were glomerulonephritis and interstitial nephritis. Serum biochemistry demonstrated that the dogs had progressive loss of renal function. L. infantum amastigotes were detected immunohistochemically in all parts of the urinary system, except the ureters. There was a correlation between parasite load, severity of histopathological changes and immunodetection of the parasites, but parasite load was not correlated with the serum biochemical parameters evaluated.