Phenolic chalcones as agents against Trichomonas vaginalis.

Trichomonas vaginalis, a flagellated and anaerobic protozoan, is a causative agent of trichomoniasis. This disease is among the world's most common non-viral sexually transmitted infection. A single class drug, nitroimidazoles, is currently available for the trichomoniasis treatment. However, resistant isolates have been identified from unsuccessfully treated patients. Thus, there is a great challenge for a discovery of innovative anti-T. vaginalis agents. As part of our ongoing search for antiprotozoal chalcones, we designed and synthesized a series of 21 phenolic chalcones, which were evaluated against T. vaginalis trophozoites. Structure-activity relationship indicated hydroxyl group plays a role key in antiprotozoal activity. 4'-Hydroxychalcone (4HC) was the most active compound (IC50 = 27.5 µM) and selected for detailed bioassays. In vitro and in vivo evaluations demonstrated 4HC was not toxic against human erythrocytes and Galleria mellonella larvae. Trophozoites of T. vaginalis were treated with 4HC and did not present significant reactive oxygen species (ROS) accumulation. However, compound 4HC was able to increase ROS accumulation in neutrophils coincubated with T. vaginalis. qRT-PCR Experiments indicated that 4HC did not affect the expression of pyruvate:ferredoxin oxidoreductase (PFOR) and ß-tubulin genes. In silico simulations, using purine nucleoside phosphorylase of T. vaginalis (TvPNP), corroborated 4HC as a promising ligand. Compound 4HC was able to establish interactions with residues D21, G20, M180, R28, R87 and T90 through hydrophobic interactions, π-donor hydrogen bond and hydrogen bonds. Altogether, these results open new avenues for phenolic chalcones to combat trichomoniasis, a parasitic neglected infection.

Hydrocarbon-based plastics: Progress and perspectives on consumption and biodegradation by insect larvae.

The obvious contrast between the remarkable durability and the high consumption of plastic products leads to the deposition of at least 100 million tons of plastics per year in nature. Since 2010, several studies have shown the potential of insect larvae to biodegrade different types of plastics, at higher rates than those reported for microorganisms. This review discusses a compilation of studies about the consumption and biodegradation of hydrocarbon-based plastics, particularly PE, PS, PP and PVC, by lepidopteran and coleopteran larvae. Insects of the Coleoptera order seem to have a better adaptation for PS biodegradation, while those of the Lepidoptera order can better biodegrade PE. Tenebrio molitor biomineralize PE and PS into CO2, and PVC into HCl; while Tenebrio obscurus and Zophobas atratus converts PE and PS into CO2, respectively. Plastic biodegradation by T. molitor has been shown to be dependent on microbiota, exception for PE. Similar PS and PE biodegradation profile has been shown for T. obscurus. PS, PP and PE biodegradation by Z. atratus is also reported to be microbial-dependent. For Galleria mellonella, microbial role on PE biodegradation is still controversial, but the PS metabolism was proved to be microbiota-independent. Advances in this field has stimulated new studies with other insect species, which need to be better explored. Uncovering and understanding the chemical processes behind the innate plastic biodegradation by insect larvae will open the perspective to new eco-friendly innovative biotechnological solutions for the challenge of plastic waste.

Virulence of Candida haemulonii complex in Galleria mellonella and efficacy of classical antifungal drugs: a comparative study with other clinically relevant non-albicans Candida species.

Candida haemulonii complex has emerged as notorious yeasts causing invasive infections with high rates of treatment failures. Since there is a particular interest in the development of non-mammalian host models to study microbial virulence, with the aim to evade the ethical impact of animal tests, herein we compared the virulence of C. haemulonii, C. duobushaemulonii and C. haemulonii var. vulnera with non-albicans Candida species (C. tropicalis, C. krusei and C. lusitaniae) on Galleria mellonella and the efficacy of antifungal drugs. All these fungi induced a dose-dependent effect on larvae killing, a decrease in hemocyte density and fungi were phagocytozed by hemocytes in equal proportions. Fungal inoculation caused early larvae melanization after some minutes of injection, followed by an augmented pigmentation after 24 h. Differences among species virulence can be explained, in part, by differences in growth rate and production of hydrolytic enzymes. First-line antifungals were tested with equivalent therapeutic doses and MIC profile in vitro was correlated with in vivo antifungal efficacy. Additionally, fungal burden increased in infected larvae along time and only caspofungin reduced the number of CFUs of C. haemulonii species complex. So, G. mellonella offers a simple and feasible model to study C. haemulonii complex virulence and drug efficacy.

Natural Green coating inhibits adhesion of clinically important bacteria.

Despite many advances, biomaterial-associated infections continue to be a major clinical problem. In order to minimize bacterial adhesion, material surface modifications are currently being investigated and natural products possess large potential for the design of innovative surface coatings. We report the bioguided phytochemical investigation of Pityrocarpa moniliformis and the characterization of tannins by mass spectrometry. It was demonstrated that B-type linked proanthocyanidins-coated surfaces, here termed Green coatings, reduced Gram-positive bacterial adhesion and supported mammalian cell spreading. The proposed mechanism of bacterial attachment inhibition is based on electrostatic repulsion, high hydrophilicity and the steric hindrance provided by the coating that blocks bacterium-substratum interactions. This work shows the applicability of a prototype Green-coated surface that aims to promote necessary mammalian tissue compatibility, while reducing bacterial colonization.

Formulation and quality control of semi-solid containing harmless bacteria by-products: chronic wounds pro-healing activity.

Chronic wounds are those that remain in a chronic inflammatory state and fail to follow normal healing process. Infection is one of the most important causes of chronicity. A frequent pathogen isolated from chronic infections is Pseudomonas aeruginosa; refractory to therapy and host immune attack in its biofilm phenotype. Lactobacillus plantarum cultures supernatants (LAPS) interfere with its pathogenic capacity. In addition, LAPS showed bacteriostatic and bactericide properties and is neither cytotoxic nor an inductor of necrosis-apoptosis. LAPSs chemical composition was determined; allowing us to propose a correlation between its constituents and their biological activity. This article shows a pharmaceutical dosage form designed by using LAPS as an API with pro-healing activity and its quality control. Pharmacotechnical and anti-microbial assays were adapted to demonstrate that the vehicle used does not modify LAPS activities. Selected formulation (F100) showed fair mechanical and technological properties. From the in vitro release assays was found an adequate release from the carrier matrix and maintains its anti-pathogenic activity for 6 months. We propose F100 for chronic wounds treatment. The use of harmless bacteria by-products, such as LAPS, to antagonize infectious pathogens that have ability to form biofilm is an efficient and economic approach to treat infected chronic wounds.

Tannins possessing bacteriostatic effect impair Pseudomonas aeruginosa adhesion and biofilm formation.

Plants produce many compounds that are biologically active, either as part of their normal program of growth and development or in response to pathogen attack or stress. Traditionally, Anadenanthera colubrina, Commiphora leptophloeos and Myracrodruon urundeuva have been used by communities in the Brazilian Caatinga to treat several infectious diseases. The ability to impair bacterial adhesion represents an ideal strategy to combat bacterial pathogenesis, because of its importance in the early stages of the infectious process; thus, the search for anti-adherent compounds in plants is a very promising alternative. This study investigated the ability of stem-bark extracts from these three species to control the growth and prevent biofilm formation of Pseudomonas aeruginosa, an important opportunistic pathogen that adheres to surfaces and forms protective biofilms. A kinetic study (0-72 h) demonstrated that the growth of extract-treated bacteria was inhibited up to 9 h after incubation, suggesting a bacteriostatic activity. Transmission electron microscopy and fluorescence microscopy showed both viable and nonviable cells, indicating bacterial membrane damage; crystal violet assay and scanning electron microscopy demonstrated that treatment strongly inhibited biofilm formation during 6 and 24 h and that matrix production remained impaired even after growth was restored, at 24 and 48 h of incubation. Herein, we propose that the identified (condensed and hydrolyzable) tannins are able to inhibit biofilm formation via bacteriostatic properties, damaging the bacterial membrane and hindering matrix production. Our findings demonstrate the importance of this abundant class of Natural Products in higher plants against one of the most challenging issues in the hospital setting: biofilm resilience.

The effects of angiotensin II and genetic hypertension upon extracellular nucleotide hydrolysis by rat platelet ectoenzymes.

The extracellular nucleotides, ATP and ADP, as well as adenosine have been implicated in a great number of physiological functions. ADP is one of the major platelet recruiting factors, whereas ATP is considered to be a competitive inhibitor of ADP-induced platelet aggregation and adenosine is able to induce vasodilatation and to inhibit platelet aggregation. The di- and triphosphate nucleosides can be hydrolyzed by members of several families of ectonucleotidases, including ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases) and ecto-nucleotide pyrophosphatase/phosphodiesterases (E-NPPs) that, together with an ecto-5'-nucleotidase, catalyze adenosine formation. The renin-angiotensin system is the most important regulator of renal and cardiovascular functions and angiotensin II induces, physiologically, platelet activation. The aim of this study was to clarify the effects of ANGII and genetic hypertension upon extracellular nucleotide hydrolysis by rat platelet ectoenzymes. ANGII, in all tested doses (5, 50, 500 and 5000 pmol), was able to increase ATP (21, 31, 44 and 27%, respectively), ADP (22, 28, 78 and 37%, respectively) and AMP (40, 64, 60 and 64%, respectively) hydrolysis by rat platelets. Furthermore, losartan, a specific antagonist of the AT1 angiotensin-receptor, prevented the nucleotide hydrolysis effects. Additionally, an increase in AMP (about 144%) hydrolysis and a decrease in p-Nph-5'TMP (about 27%) hydrolysis were observed in platelets from spontaneously hypertensive rats (SHR) when compared to Wistar normotensive rats. We, herein, present data to demonstrate interactions between rat platelet angiotensinergic and adenosinergic systems that could contribute to the understanding and treatment of cardiovascular diseases such as hypertension, thrombosis and arteriosclerosis.