Synthesis and evaluation of toxicity and antimicrobial activity of rifampicin associated with iron oxide nanoparticles

Rifampicin has broad-spectrum antimicrobial activity, but it can cause nephrotoxic and hepatotoxic damage because high doses are required. Nanosystems emerge as a perspective to improve the transport systems of this drug. In this work, iron oxide nanoparticles were synthesised, functionalized with lauric acid, and rifampicin was incorporated into the nanosystem. The samples were characterized by spectroscopic techniques: electronics in the visible ultraviolet region (UV-vis), vibrational absorption in the infrared region (IR), X-ray diffractometry (XRD), and dynamic light scattering (DSL). The toxicity of the nanocompounds and the antimicrobial activity against Staphylococcus aureus ATCC 25923 were studied by the Artemia salina lethality and disc diffusion techniques, respectively. As a result, IR analysis showed characteristic vibrations of laurate and rifampicin on the surface of the nanosystem. The presence of magnetic iron oxide was confirmed by XRD and the mean diameter of the crystallites was 8.37 nm. The hydrodynamic diameter of rifampicin associated with the nanosystem was 402 nm and that of the nanosystem without rifampicin was 57 nm. The compounds did not show toxicity to Artemia salina and the in vitro antimicrobial activity against Staphylococcus aureus was slightly decreased when rifampicin was associated with the nanosystem. In general terms, the results showed that iron oxide nanoparticles showed no toxicity and reduced the toxicity of rifampicin by 41.54% when carried compared to free rifampicin. Therefore, magnetic iron oxide nanoparticles may have the potential to act as a platform for associated drugs.

Ruthenium(II)/Benzonitrile Complex Induces Cytotoxic Effect in Sarcoma-180 Cells by Caspase-Mediated and Tp53/p21-Mediated Apoptosis, with Moderate Brine Shrimp Toxicity.

Ruthenium(II)/benzonitrile complexes have demonstrated promising anticancer properties. Considering that there are no specific therapies for treating sarcoma, we decided to evaluate the cytotoxic, genotoxic, and lethal effects of cis-[RuCl(BzCN)(phen)(dppb)]PF6 (BzCN = benzonitrile; phen = 1,10-phenanthroline; dppb = 1,4-bis-(diphenylphosphino)butane), as well as the mechanism of cell death induction that occurs against murine sarcoma-180 tumor. Thus, MTT assay was applied to assess the ruthenium cytotoxicity, showing that the compound is a more potent inhibitor for the sarcoma-180 tumor cell viability than normal cells (lymphocytes). The comet assay indicated low genotoxic for normal cells. cis-[RuCl(BzCN)(phen)(dppb)]PF6 also showed moderate lethality in Artemia salina. The complex induced cell cycle arrest in the G0/G1 phase in sarcoma-180 cells. In addition, the complex caused S180 cells to die by apoptosis by an increase in Annexin-V-positive cells and morphological changes typical of apoptotic cells. Additionally, cis-[RuCl(BzCN)(phen)(dppb)]PF6 increased the gene expression of Bax, Casp3, and Tp53 in S180 cells. By using a western blot, we observed an increased protein level of TNF-R2, Bax, and p21. In conclusion, cis-[RuCl(BzCN)(phen)(dppb)]PF6 is active and selective for sarcoma-180 cells, leading to cell cycle arrest at the G0/G1 and cell death through a caspases-mediated and Tp53/p21-mediated pathway.

Application of Gamma Radiation on Hard Gelatin Capsules as Sterilization Technique and Its Consequences on the Chemical Structure of the Material.

Hard capsules are made from gelatin, an organic polymer obtained through the hydrolysis of collagen present in animal tissues. Gelatin can be degraded by microorganisms and some strategies can be used to control contaminating micro-organisms. Gamma irradiation is considered as an effective sterilization method; however, its application can alter the chemical structure of the irradiated product. Samples of hard gelatin capsules were irradiated at doses of 5, 15, and 25 kGy at room temperature. The characterizations of the physical and chemical effects were evaluated by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffractometry, and differential scanning calorimetry techniques. Furthermore, hard gelatin capsule samples were dissolved and inoculated with Bacillus subtilis, a Gram-positive spore-forming bacterium, to evaluate the effect of gamma ray radiation on bacterial counts. The results showed that gamma radiation did not interfere on physical parameters of the capsule, such as moisture content, mass, body and cap length, and disintegration time. Nevertheless, differential scanning calorimetry results demonstrated changes in the glass transition temperature, indicating the formation of crosslinking in irradiated capsules. It was observed that there were significant reductions on the inoculated bacterial population starting from the lowest irradiation dose and there was no detection of bacterial growth from the 15 kGy dose, while in the non-irradiated samples were found with 104 CFU mL-1 of bacteria. Therefore, this work concludes that the gamma radiation is effective on the reduction of the microbial population, cause discrete physical-chemical alterations, and could be used as a hard capsule sterilization technique.

Inhibition of bacterial biofilms by carboxymethyl chitosan combined with silver, zinc and copper salts.

Investigation of the antimicrobial action of carboxymethyl chitosan (CMCh) is among the alternative approaches in the control of pathogenic microorganisms. This study aimed to screen the toxicity using the brine shrimp lethality assay and to investigate the inhibitory activity of carboxymethyl in isolation or in combination with silver nitrate, copper sulfate and zinc sulfate on biofilm formation by Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Kocuria rhizophila ATCC 9341, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 25312, and Burkholderia cepacia ATCC 17759. The CMCh was obtained by reacting chitosan with monochloroacetic acid under alkaline conditions, and the occurrence of carboxymethylation was evidenced by FTIR and 1H NMR spectroscopy. The CMCh was combined with metallic salts (AgNO3, CuSO4·5H2O and ZnSO4) to perform the bioassays to screen the toxicity, to determine the minimum inhibitory concentration and the impact of sub-inhibitory concentrations against biofilm formation. Although CMCh did not show inhibitory activity against bacterial growth, it had an interesting level of inhibition of bacterial biofilm. The results suggest that sub-inhibitory concentrations of compounds were effective against biofilm formation.

Cell surface hydrophobicity and biofilm formation of candida yeast species in different culture media / Hidrofobicidade da superfície celular e formação de biofilme de Candida sp em diferentes meios de cultura

Cell surface adhesion is considered an essential step in the spread, infection and persistence of Candida yeasts in the host. Their ability to adhere on biotic and abiotic surfaces depends on several factors, including hydrophobicity. Once attached, these yeasts are capable of growing in biofilms, which are constituted of structured communities of encapsulated cells within an extracellular matrix, resistant to antifungal agents. In this context, this study aimed to analyze the cell surface hydrophobicity and specific biofilm formation of six Candida strains in different culture media: Sabouraud dextrose broth (SDB), artificial saliva (AS), Roswell Park Memorial Institute medium (RPMI 1640) and N-acetylglucosamine-yeast nitrogen base proline (NYP). Six yeasts of the genus Candida were studied: three C. albicans (Ca): Ca ATCC 10231 and the clinical isolates Ca34 and Ca05 and C. parapsilosis (Cp): Cp ATCC 22019 and the clinical isolates Cp120 and Cp38. Hydrophobicity was calculated as the percentage reduction in turbidity of the aqueous phase, due to the retention of the hydrophobic cells in hydrocarbon by the hydrocarbon-water biphasic assay following the MATH (Microbial Adhesion to Hydrocarbon) method. The biofilm formation index was calculated as the optical density obtained by the growth of the yeasts in the culture media in a polystyrene microtiter plate, subsequently stained with 1% violet crystal. The results showed that hydrophobicity varied according to the media and the yeasts studied, and two of these (Ca34 and Ca10231) presented significant variation between the media. A more hydrophobic character was observed in yeasts grown on RPMI-1640 medium, and those grown on Sabouraud dextrose broth appeared more hydrophilic. The specific biofilm formation index was more intense for RPMI 1640 than in other media, which was expected, due to its ability to induce the transition between yeast-hyphae morphology, which is one of the key factors involved in the adhesion of C. albicans on different surfaces. RPMI 1640 was the best medium for obtaining biofilm in vitro, due to its greater hydrophobicity, which can enhance cell adhesion to the polystyrene plate, and due to its nutrient content, necessary for complete cell growth and biofilm formation.

A adesão é considerada um passo essencial para a disseminação, infecção e persistência das leveduras do gênero Candida nos hospedeiros. A habilidade dessas leveduras em se aderir a superfícies bióticas e abióticas depende de fatores, incluindo a hidrofobicidade da superfície celular. Uma vez aderidas, estas leveduras são capazes de crescer como biofilmes, os quais são caracterizados como comunidades estruturadas de células encapsuladas dentro de uma matriz extracelular, resistentes a drogas antifúngicas. Neste contexto, objetivou-se analisar a hidrofobicidade da superfície celular e a formação específica de biofilme de Candida spp. em diferentes meios de cultura: caldo Sabouraud dextrose (CSD), saliva artificial (SA), Roswell Park Memorial Institute medium (RPMI 1640) e N-acetylglucosamineyeast nitrogen base-proline (NYP). Foram estudadas seis leveduras do gênero Candida, sendo três C. albicans (Ca): Ca ATCC 10231 e os isolados clínicos Ca34 e Ca05 e C. parapsilosis (Cp): Cp ATCC 22019 e os isolados clínicos Cp120 e Cp38. A hidrofobicidade foi calculada como a porcentagem da redução da turbidez da fase aquosa, devido a retenção das células hidrofóbicas no hidrocarboneto pelo método bifásico água-hidrocarboneto MATH (Teste de Adesão Microbiana a Hidrocarbonetos). O índice de formação de biofilme foi calculado com as densidades ópticas obtidas por meio do crescimento das leveduras nos meios de cultura em poços de placa de microtitulação de poliestireno e posteriormente corados com cristal violeta a 1%. Os resultados demonstraram que a hidrofobicidade variou de acordo com os meios e as leveduras estudadas, sendo que duas (Ca34 e Ca10231) apresentaram variação significativa entre os meios. Foi verificado um caráter mais hidrofóbico das células crescidas em RPMI 1640 e mais hidrofílico nas células crescidas em caldo Sabouraud dextrose. A formação específica de biofilme apresentou-se mais intensa em RPMI 1640 do que nos outros meios, o que já era esperado pela sua capacidade de induzir o processo de transição levedura-hifa, o qual é considerado um dos fatores cruciais envolvidos na adesão de leveduras. Com os resultados obtidos, infere-se que o RPMI 1640 é o melhor meio para obtenção de biofilme in vitro, pois as células foram mais hidrofóbicas, o que pode aumentar a adesão das

Cromoblastomicose: Doença presente na realidade populacional brasileira / Chromoblastomicosis: present disease in brazilian population reality

A cromoblastomicose é uma infecção localizada crônica da pele e tecido subcutâneo preferencialmente envolvendo membros inferiores e caracterizada por lesões geralmente verrucosas. Em muitos casos, as lesões são unilaterais e são causadas por fungos dematiáceos. A doença é muito comum em regiões tropical e subtropical. Os agentes etiológicos de cromoblastomicose são dispersos no meio ambiente, sendo encontrados no solo e na vegetação em decomposição. A infecção ocorre pela inoculação traumática do fungo na pele e a micose é muito prevalecente entre indivíduos com ocupações ao ar livre e que andam dascalços, sendo comum nos homens. Ainda é uma doença fúngica presente principalmente na população rural brasileira.

Avaliaçäo da microbiotica fúngica so ar na clínica de periodontia - FO/UFG / Evaluation of the fungi microbiota of the air in the periodontic clinic - FOUFG

Os fungos säo tidos como um dos microrganismos mais dispersos pelo ar. A contaminaçäo ambiental fúngica, além de ser frequente, proporciona a açäo destes seres vivos como agentes patogênicos de doenças respiratórias e oportunistas. Este estudo objetivou avaliar a contaminaçäo fúngica do ar da Clínica de Periodontia da Faculdade de Odontologia da Universidade Federal de Goiás (FO/UFG). As amostras foram coletadas em placas de Petri aberta, contendo ágar infusão cérebro-coraçäo, mediante a sua exposiçäo ao ambiente por 30 minutos, após atendimento dos pacientes. As colônias fúngicas desenvolvidas foram repicadas em ágar Sabouraud e identificadas por características macroscópicas e microcultivo. Os fungos detectados compreenderam 6 cepas de Aspergillus sp.;1 de Penicillium sp.; 1 de Curvularia sp.; 1 de Mycella sterelia; 1 Botrytis sp. e 2 fungos filamentosos negros; além de um isolado bacteriano Nocardia sp. O resultado mostrou que as condiçöes ambientais da clínica de Periodontia não estavam adequadas e medidas de controle devem ser revistas