Mechanical properties, fluorine release behavior and bacterial inhibition of hydroxyapatite-glass ionomer cement / 实用口腔医学杂志

Objective:To investigate mechanical properties,fluorine release behavior and bacteria inhibition effect of hydroxyapatite-improved glass ionomer cement(HA/GIC).Methods:HA/GIC was prepared with HA mass fraction of 28％.Bending strength and compressive strength of HA/GIC and GIC were measured by an universal material testing machine.Microstructure of the materials was observed by scanning microscope technique (SEM).Accumulation of fluorine release was measured by fluorine ion selective electrode.Bacterial inhibition of total bacteria and Streptococcus mutans was monitored by fluorescence in situ hybridization.Results:Bending strength,compressive strength and fluorine release accumulation of HA/GIC were significantly higher than those of GIC (P ＜ 0.05).There were many.irregular polymerized particle monomers and micro cracks within the GIC.In HA/GIC,hydroxyapatite particles were connected with original composition.Bacterial inhibition of total bacteria and Streptococcus mutans by HA/GIC was more effective than that by GIC.Conclusion:HA/GIC has perfect mechanical properties,fluorine release behavior and bacterial inhibition effect.

Methanogenic toxicity evaluation of chlortetracycline hydrochloride

Background Anaerobic digestion is a technology applied successfully to converting organic matter into biogas. However, the presence of inhibitory compounds such as antibiotics can adversely affect methane production. The aim of this study is to evaluate the toxic effect of chlortetracycline hydrochloride (CLOR) on the methanogenic bacteria. In order to study the methanogenic toxicity of CLOR, different concentrations of CLOR (10, 50, 100, 200 mg L- 1) were evaluated by methanogenic toxicity assays using three feedings. Results Maximum methane production was obtained for the assays with 10 mg CLOR L- 1, the values obtained were 277 ± 4.07; 193 ± 11.31 and 166 ± 7.07 mL for the first, second and third feedings, respectively. The average values for acetic, propionic and butyric acid at start of the experiments were 2104 ± 139; 632 ± 7.6; 544 ± 26 mg L- 1, respectively. The VFA values obtained finally of the experiment were dependent on the evaluated antibiotic concentrations, indicating that the efficiency of methanogenesis is directly affected by the CLOR concentration. Conclusions CLOR is an effective methanogenic bacteria inhibitor. Moreover, the results show that CLOR has a bactericidal effect on methanogenic activity given that methane production did not recover during the third feeding. This study shows that the 50% inhibitory concentration (IC50) for methanogenic bacteria in 10 mg L- 1.

Atividade antibacteriana in vitro de inflorescências de Achyrocline satureioides (Lam.) DC. - Asteraceae ("macela", "marcela") sobre agentes bacterianos de interesse em alimentos / In vitro antibacterial activity of inflorescences of Achyroclines satureioides (Lam.) DC. - Asteraceae ("macela", "marcela") on bacterial agents of interest in food

Através de Testes de diluição em sistema de tubos múltiplos determinou-se in vitro, atividade antibacteriana em inflorescências de Achyrocline satureioides (Lam.) DC. - Asteraceae ("macela", "marcela"), expressa como Intensidade de Atividade de Inibição Bacteriana (IINIB/bacteriostasia) e Intensidade de Atividade de Inativação Bacteriana (IINAB/bactericidia), a partir de formas de extração etanólica (hidroalcoolaturas) e hídrica (decoctos), sobre inóculos padronizados de Enterococcus faecalis (ATCC 19433), Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 11229) e Salmonella enteritidis (ATCC 11076). E. faecalis apresentou a maior sensibilidade, seguido por Staphylococcus aureus, enquanto S. enteritidis e E. coli apresentaram-se mais resistentes. Dentre as formas de extração, a hidroalcoolatura apresentou capacidade de inibição e/ou inativação intensa e seletiva frente aos quatro inóculos bacterianos. Os decoctos mostraram-se completamente ineficazes frente às bactérias Gram-negativas, enquanto que as Gram-positivas apresentaram somente bacteriostasia/inibição.

Dilution test in multiple tube system was used to determine the in vitro antibacterial activity in inflorescences of Achyrocline satureioides (Lam.) DC. - Asteraceae ("macela", "marcela"), expressed as intensity of bacterial inhibition activity (IINIB/bacteriostasis) and intensity of bacterial inactivation activity (IINAB/bactericidie), from ethanol (hydroalcoholic) and water (decoction) extraction forms on standardized inocula of Enterococcus faecalis (ATCC 19433), Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 11229) and Salmonella enteritidis (ATCC 11076). E. faecalis had the highest sensitivity, followed by S. aureus, while S. enteritidis and E. coli were more resistant. Of the extraction forms, the hydroalcoholic one showed intense and selective inhibition and/or inactivation capacity against four bacterial inocula. Decoctions were completely ineffective against the Gram-negative bacteria, whereas Gram-positive bacteria showed only bacteriostasis/inhibition.

Atividade antibacteriana in vitro de pimentas e pimentões (Capsicum sp. ) sobre quatro bactérias toxinfectivas alimentares / In vitro antibacterial activity of hot and sweet peppers (Capsicum sp. ) on four food toxinfective bacteria

Determinou-se in vitro a Intensidade de Atividade de Inibição Bacteriana (IINIB) e a Intensidade de Atividade de Inativação Bacteriana (IINAB), através de Testes de Diluição em Sistema de Tubos Múltiplos, de extratos de oito pimentas do gênero Capsicum, etnograficamente acessadas na região metropolitana de Porto Alegre/RS/BR, frente a inóculos bacterianos padronizados (American Type Culture Collection - ATCC), respectivamente Staphylococcus aureus (25923), Enterococcus faecalis (19433), Salmonella enteritidis (13076) e Escherichia coli (11229), em doses-desafio = 10(7) UFC mL-1. Quatro destas plantas, pimenta calabresa ("pool" Capsicum sp), pimenta-de-jardim (C.annuum), pimenta dedo-de-moça (C. baccatum) e pimenta malagueta (C. frutescens), apresentaram atividades de inibição e inativação seletivas, em ordem decrescente, para salmonela, coliforme fecal, enterococo e estafilococo. As demais, pimenta cambuci (C. baccatum) e os pimentões (C. annuum) amarelo, verde e vermelho, apresentaram nenhuma atividade. Discute-se a validade da ferramenta etnográfica na prospecção de fatores de proteção anti-bacteriana em plantas, bem como a influência da inibição/inativação na preditividade do diagnóstico bacteriológico.

The intensity of bacterial inhibition activity (IINIB) and the intensity of bacterial inactivation activity (IINAB) of extracts of eight peppers of the genus Capsicum, ethnographically located in the metropolitan region of Porto Alegre, Rio Grande do Sul State, Brazil, were assessed in vitro through Dilution Tests in Multiple Tube Series against standardized bacterial inocula (American Type Culture Collection - ATCC), Staphylococcus aureus (25923), Enterococcus faecalis (19433), Salmonella enteritidis (13076), and Escherichia coli (11229), respectively, at challenge doses = 10(7) CFU mL-1. Four of these species, cayenne pepper (Capsicum sp pool), garden pepper (C. annuum), ají pepper (C. baccatum), and malagueta pepper (C. frutescens), had selective inhibition and inactivation activities, in decreasing order, to salmonella, fecal coliforms, enterococcus and staphylococcus. The remaining ones, cambuci pepper (C. baccatum) and yellow, green and red sweet peppers (C. annuum) had no activity. The validity of the ethnographic tool in the exploration of antibacterial protection factors from plants, as well as the influence of inhibition/inactivation in the bacteriological diagnosis predictability, is discussed.

Growth and antibacterial activity of Lentinula edodes in liquid media supplemented with agricultural wastes

Antibacterial activity of Lentinula edodes against Bacillus subtilis was evaluated in cell-free filtrates obtained after growth in 14 different culture media. The highest B. subtilis growth inhibition was promoted by filtrates of growth media supplemented with rice bran, vermiculite or molasses. L. edodes dry mycelial biomass in liquid culture with 0.5% added rice bran was 3.2 mg/ml, after growth for 30 days at 25ºC without shaking, and 4.3 mg/ml under orbital shaking (150 rpm). However, antibacterial activity, detected between 20 and 24 days of incubation of stationary cultures, was absent in filtrates of aerated cultures. Temperatures of 20-25ºC enhanced both growth and antibacterial activity. Optimum pH for L. edodes mycelial growth was 3.0-3.5, while for production of antibacterial substance(s) it was 4.5. Our results indicated that incubation conditions that enhance mycelial growth are quite different from those necessary for production of antibacterial substance(s) by L. edodes.