Archaea diversity in vegetation gradients from the Brazilian Cerrado

Abstract We used 16S rRNA sequencing to assess the archaeal communities across a gradient of Cerrado. The archaeal communities differed across the gradient. Crenarcheota was the most abundant phyla, with Nitrosphaerales and NRPJ as the predominant classes. Euryachaeota was also found across the Cerrado gradient, including the classes Metanocellales and Methanomassiliicoccaceae.

Crude glycerol from biodiesel industry as substrate for biosurfactant production by Bacillus subtilis ATCC 6633

Glycerol, a co-product of the biodiesel industry, may be a suitable raw material for the production of high added-value compounds by the microorganisms. This study aimed to use the glycerol obtained from the biodiesel production process as the main carbon source for biosurfactant production by Bacillus subtilis ATCC 6633. Results indicated that the strain lowered the surface tension of the cell-free fermented broth to 31.5 ± 1.6 mN/m, indicating the production of biosurfactant. The critical micelle concentration (CMC = 33.6 mN/m) obtained was similar to the previously reported for biossurfactants isolated from other Bacillus. The produced biosurfactant was able to emulsify n-hexadecane and soybean oil.

Interaction of antimicrobial peptide Plantaricin149a and four analogs with lipid bilayers and bacterial membranes

The amidated analog of Plantaricin149, an antimicrobial peptide from Lactobacillus plantarum NRIC 149, directly interacts with negatively charged liposomes and bacterial membranes, leading to their lysis. In this study, four Pln149-analogs were synthesized with different hydrophobic groups at their N-terminus with the goal of evaluating the effect of the modifications at this region in the peptide's antimicrobial properties. The interaction of these peptides with membrane models, surface activity, their hemolytic effect on red blood cells, and antibacterial activity against microorganisms were evaluated. The analogs presented similar action of Plantaricin149a; three of them with no hemolytic effect (< 5%) until 0.5 mM, in addition to the induction of a helical element when binding to negative liposomes. The N-terminus difference between the analogs and Plantaricin149a retained the antibacterial effect on S. aureus and P. aeruginosa for all peptides (MIC50 of 19 µM and 155 µM to Plantaricin149a, respectively) but resulted in a different mechanism of action against the microorganisms, that was bactericidal for Plantaricin149a and bacteriostatic for the analogs. This difference was confirmed by a reduction in leakage action for the analogs. The lytic activity of Plantaricin149a is suggested to be a result of the peptide-lipid interactions from the amphipathic helix and the hydrophobic residues at the N-terminus of the antimicrobial peptide.

Antimicrobial effect of a crude sulfated polysaccharide from the red seaweed Gracilaria ornata

The aim of this study was to determine the yield, chemical composition, specific rotation (SR), infrared (IR) spectroscopy and the effect on bacterial growth of a crude sulfated polysaccharide (SP) from the red marine alga G. ornata (Go). Go-1 (25°C), Go-2 (80°C), and Go-3 (80°C) were sequentially extracted and yielded 9.2%. The contents of sulfate (5.88-10.3%) and proteins (0.1-3.7%) were small. The values of SR were [µ]D20°f -19.0, -51.0, and -56.5, respectively. IR spectrums showed the presence of galactose-4 sulfate and absence of 3,6-anydrogalactose-2 sulfate, galactose-6 sulfate and galactose-2 sulfate. SR and IR techniques confirmed SPs. Go-3 was tested on the growth of bacteria (Bacillus subtilis, Staphylococcus aureus, Enterobacter aerogens, Escherichia coli, Pseudomonas aeruginosa, Salmonela choleraesuis and Salmonela typhi), but only E. coli was inhibited.

Avaliação microbiológica de equipamentos, utensílios e manipuladores de alimentos, em Unidades de Alimentação e Nutrição da Universidade Federal do Ceará / Microbiological evaluation of equipment, utensils and food handlers, in Units of Food and Nutrition, Federal University of Ceará

Registros epidemiológicos revelam que a maioria dos surtos de doenças de origem alimentar é atribuída a patógenos veiculados em alimentos preparados em Unidades de Alimentação e Nutrição (UAN). Nas UAN as etapas de preparação dos alimentos mudam constantemente e o risco de contaminações cruzadas, sejam elas em superfícies ou por manipulação humana incorreta, é elevado. O objetivo deste trabalho foi avaliar uma UAN localizada no Campus do PICI da Universidade Federal do Ceará(UFC) em relação as condições higiênico-sanitárias no preparo e distribuição de alimentos...

Effect of proteins from the red seaweed Hypnea musciformis (Wulfen) Lamouroux on the growth of human pathogen yeasts

A protein fraction, rich in lectin, obtained from the red seaweed Hypnea musciformis by precipitation with ammonium sulfate (F40/70) was screened for chitinase and beta-1,3-glucanase activity and assessed for antifungal potential against the human pathogen yeasts Candida albicans and C. guilliermondii. The F40/70 fraction showed chitinase and beta-1,3-glucanase enzymes, with specific activities of 276.43 and 1880.7 Units.mg -1 protein, respectively. It was capable of inhibiting the growth of C. guilliermondii at the concentrations of 45, 100 and 450 æg protein.ml -1 but it showed only a discrete inhibition against C. albicans irrespective of the tested concentrations. The inhibitory action was shown to be fungistatic and the presence of the glycoprotein fetuin, for which the lectin in the fraction had affinity, abolished the antifungal action. The complete growth recovery following fetuin treatment indicated that chitinase and beta-1,3-glucanase were not involved in the growth inhibition of these yeasts.

Uma fração protéica, rica em lectina, obtida por precipitação com sulfato de amônia (F40/70), da alga marinha vermelha Hypnea musciformis foi avaliada quanto à presença de atividade quitinásica e beta-1,3-glucanásica e potencial antifúngico contra as leveduras patogênicas Candida albicans e C. guilliermondii. A fração F40/70 mostrou ambas as atividades enzimáticas, com atividades específicas de 276,43 e 1880,7 Unidades.mg-1 proteína, respectivamente. Essa fração foi capaz de inibir de forma significativa o crescimento da levedura C. guilliermondii nas concentrações de 45, 100 e 450 æg proteína.ml -1 porém mostrou apenas uma discreta ação contra C. albicans, independente das concentrações testadas. A ação inibitória foi fungistática e a presença da glicoproteína fetuína, para a qual a lectina na fração tem afinidade, aboliu a ação antifúngica. A recuperação completa do crescimento das leveduras após tratamento com fetuína indicou que as atividades quitinásica e beta-1,3-glucanásica não estão envolvidas na inibição do crescimento dessas leveduras.

Larvicidal activity of the essential oil from Lippia sidoides cham. against Aedes aegypti linn

The aim of this work was to study the larvicidal activity of Lippia sidoides essential oil against Aedes aegypti larvae. The essential oil and its hydrolate (saturated solution of essential oil in water) were obtained by vapor extraction and their chemical composition determined by GL-chromatography coupled to mass spectroscopy. Bioassays were run with the essential oil, pure and diluted hydrolate and with their main constituents thymol and carvacrol. The results obtained showed that L. sidoides essential oil and its hydrolate have larvicidal action against the mosquito A. aegypti, causing an almost instantaneous mortality. Thymol, an alkylated phenol derivative and one of the major components of L. sidoides essential oil, was identified as the active principle responsible for the larvicidal action, causing 100 percent larval mortality at the lowest tested concentration of 0.017 percent (w/v). These results suggest that the essential oil of L. sidoides is promising as larvicide against A. aegypti and could be useful in the search of newer, more selective, and biodegradable larvicidal natural compounds to be used in official combat programs and at home

Avaliaçäo da toxicidade de extratos de plantas medicinais através de bioensaio com Artemia salina Leach / Toxicity evaluation of medicinal plant extracts by brine shrimp bioassay

Este trabalho visa avaliar a toxicidade dos extratos de nove plantas medicinais que apresentam atividade antibiótica e que säo consumidas ampla e indiscriminadamente pela populaçäo (Lippia didoides, Lippia gracillis, Stenocalyx michelli, Punica granatum, Mimosa hostilis, Psidium guajava, Ccombretum leprosum, Mentha cf. rotundifolia e Coleus amboinicus). Para tanto, optou-se pelo uso de um bioensaio que utiliza um microcrustáceo (Artemia salina Leach) como organismo-teste. Cada extrato de planta (aquoso, acetônico e hidroalcoólico) foi testado na concentraçäo inibitória mínima. Os resultados mostraram que o extrato aquoso de Punica granatum, Stenocalyx michelli e Psidium guajava apresentaram uma taxa de sobrevivência de 92, 79 e 91%, respectivamente; o extrato acetônico de Stenocalyx michelli e Combretum leprosum, uma taxa de sobrevivência de 81 e 96%, respectivamente, e o extrato hidroalcoólico de Combretum leprosum uma taxa de sobrevivyencia de 73%. Os outros extratos testado näo apresentaram sobreviventes. Com esses resultados chegou-se a conclusäo de que, entre dezoito extratos diferentes de plantas, somente seis extratos näo apresentaram toxicidade chegou-se a conclusäo de que, entre dezoito extratos diferentes de plantas, somente seis extratos näo apresentaram toxicidade a Artemia salina, o que sugere que as concentraçöes testadas (CIMs) estavam abaixo da LC50 de cada extrato