Cyclic lipopeptide signature as fingerprinting for the screening of halotolerant Bacillus strains towards microbial enhanced oil recovery.

Cyclic lipopeptides (CLPs) are non-ribosomal biosurfactants produced by Bacillus species that exhibit outstanding interfacial activity. The synthesis of CLPs is under genetic and environmental influence, and representatives from different families are generally co-produced, generating isoforms that differ in chemical structure and biological activities. This study to evaluate the effect of low and high NaCl concentrations on the composition and surface activity of CLPs produced by Bacillus strains TIM27, TIM49, TIM68, and ICA13 towards microbial enhanced oil recovery (MEOR). The strains were evaluated in mineral medium containing NaCl 2.7, 66, or 100 g L-1 and growth, surface tension and emulsification activity were monitored. Based on the analysis of 16S rDNA, gyrB and rpoB sequences TIM27 and TIM49 were assigned to Bacillus subtilis, TIM68 to Bacillus vallismortis, and ICA13 to Bacillus amyloliquefaciens. All strains tolerated up to 100-g L-1 NaCl, but only TIM49 and TIM68 were able to reduce surface tension at this concentration. TIM49 also showed emulsification activity at concentrations up to 66-g L-1 NaCl. ESI-MS analysis showed that the strains produced a mixture of CLPs, which presented distinct CLP profiles at low and high NaCl concentrations. High NaCl concentration favored the synthesis of surfactins and/or fengycins that correlated with the surface activities of TIM49 and TIM68, whereas low concentration favored the synthesis of iturins. Taken together, these findings suggest that the determination of CLP signatures under the expected condition of oil reservoirs can be useful in the guidance for choosing well-suited strains to MEOR.

Cytotoxic activity of fungal strains isolated from the ascidian Eudistoma vannamei.

The cytotoxic activity at 50 µg/ml of extracts obtained from eleven fungal strains associated to Eudistoma vannamei, an endemic ascidian from Northeast Brazil, against two cell lines, i.e., the HCT-8 (colon cancer) and the MDA-MB-435 (melanoma) cell lines, was investigated. The most promising extract (EV10) was obtained from a fungus identified as Aspergillus sp. by molecular analysis and was selected for bioassay-guided isolation of its active principals. Large-scale fermentation of EV10 in potato-dextrose broth followed by chromatographic purification of the active extract from the liquid medium allowed the isolation of the isocoumarins mellein, cis-4-hydroxymellein, and trans-4-hydroxymellein, besides penicillic acid. All isolated compounds were tested for their cytotoxicity against the tumor cell lines MDA-MB-435 and HCT-8 and revealed penicillic acid as the only cytotoxic compound (cell growth inhibitions >95%).

Larvicidal activity of the water extract of Moringa oleifera seeds against Aedes aegypti and its toxicity upon laboratory animals

In this work, biological effects of the water extract of Moringa oleifera seeds (WEMOS) were assessed on eggs and 3rd instar larvae of Aedes aegypti and on its toxicity upon laboratory animals (Daphnia magna, mice and rats). Crude WEMOS showed a LC50 value of 1260µg/mL, causing 99.2 ± 2.9 percent larvae mortality within 24 h at 5200µg/mL, though this larvicidal activity has been lost completely at 80ºC/10 min. WEMOS did not demonstrate capacity to prevent egg hatching. After extensive dialyses of the crude WEMOS into watersoluble dialyzable (DF) and nondyalizable (NDF) fractions, only DF maintained its efficacy to kill larvae. Acute toxicity evaluations on daphnids (EC50 of 188.7µg/mL) and mice (LD50 of 446.5 mg/kg body weight) pointed out to low toxicity. Despite the thymus hypertrophy, WEMOS revealed to be harmless in orally and subacutelytreated rats. In conclusion, WEMOS has thermostable bioactive compounds against Ae. aegypti larvae with apparent molecular mass lower than 12 kDa and moderately toxic potential.

Neste trabalho, o extrato aquoso das sementes de Moringaoleifera (EASMO) foi avaliado quanto aos seus efeitos biológicos sobre ovos e larvas de Aedes aegypti no 3ºestágio de desenvolvimento e sua toxicidade sobre animais de laboratório(Daphnia magna, camundongos e ratos). O EASMO bruto revelou uma CL50 de 1.260 µg/mL, causando 99, 2 ± 2, 9 por cento de mortalidade em 24 h na concentração de 5.200 µg/mL, embora o mesmo não tenha sido capaz de impedir a eclosão dos ovos. A atividade larvicida extinguiu-se após aquecimento do extrato a 80ºC/10 min. Diálises sucessivas do EASMO bruto resultaram em duas frações solúveis em água (Fração dializável, FD; Fração nãodializável, FND), dentre as quais apenas a FD mostrou ação larvicida. Testes de toxicidade aguda realizadosem dáfnias (CE50 de 188, 7 µg/mL) e camundongos (DL50 de446,5 mg/kg de peso corpóreo) evidenciaram baixa toxicidade. Apesar da hipertrofia tímica, o EASMO mostrou ser atóxicoapós tratamento subagudo via oral em ratos. Conclui-se, portanto, que o EASMO apresenta substâncias com capacida de larvicida contra Ae. aegypti, as quais possuem massa molecular aparente menor que 12 kDa e potencial tóxico moderado.

Atividades biológicas e enzimáticas do extrato aquoso de sementes de Caesalpinia ferrea Mart., Leguminosae / Biological and enzymatic activities of aqueous extract of seeds from Caesalpinia ferrea Mart., Leguminosae

Caesalpinia ferrea Mart. (jucá ou pau-ferro) é uma espécie da família Leguminosae cuja ocorrência estende-se da região Nordeste ao Estado do Rio de Janeiro. Trata-se de uma espécie bastante utilizada na medicina popular pelas suas inúmeras propriedades terapêuticas tais como antiinflamatória, analgésica, antimicrobiana e antitérmica as quais indicam a presença de compostos de interesse farmacológico. Contudo, muitos estudos em plantas também investigam a presença de compostos de interesse industrial. Com base nas propriedades terapêuticas e atividades já descritas para essa espécie, esse trabalho objetivou pesquisar atividades biológicas no extrato de sementes de C. ferrea na busca por compostos de interesse industrial e farmacológico. Os resultados indicaram a presença das atividades celulásica, amilásica, anticoagulante e larvicida contra A. aegypti no extrato aquoso das sementes de C. ferrea, entretanto, não foram observadas as atividades tóxica aguda, hemolítica, heparinásica, antibacteriana e antifúngica.

Caesalpinia ferrea Mart. is a species belonging to Leguminosae family commonly known in Brazil as "jucá" or "pau-ferro". It occurs in Brazil from the Northeast Region to the State of Rio de Janeiro and it is widely utilized in folk medicine due to its several therapeutic properties such as anti-inflammatory, analgesic, antimicrobial and antithermic, which indicate the presence of compounds of pharmacological interest. Besides, many studies with plants look for the presence of compounds with industrial applications. Based upon the therapeutic and bioactive properties described for this species so far, this work aimed to investigate several biological activities in the water extract of C. ferrea seeds. The results indicated the presence of the following activities: cellulase, amylase, anticoagulant and larvicide against A. aegypti in the water extract of C. ferrea seeds. Nevertheless, the extract did not show the other activities assayed: acute toxic activity, hemolytic, heparinasic, antibacterial and antifungal activities.

Isolation and characterization of novel peptides from chilli pepper seeds: antimicrobial activities against pathogenic yeasts.

Different types of antimicrobial peptides have been identified in seeds from different plant species. The aim of this study was to isolate and characterize peptides present in chilli pepper seeds (Capsicum annuum L.) and evaluate their toxic activities against some yeast species. Initially, proteins from seed flour were extracted in phosphate buffer, pH 5.4, for 3 h at 4 degrees C and the pellet obtained at 90% saturation with ammonium sulfate was heated at 80 degrees C for 15 min. The resulting suspension was clarified by centrifugation and the supernatant was extensively dialyzed against water; the peptide-rich extract was then named F/0-90. Cation-exchange chromatography was performed to separate low molecular mass proteins. One of the resulting fractions, named F3, enriched with basic proteins of 6-16 kDa, was submitted to reverse-phase chromatography in a C2/C18 column by HPLC, resulting in four fractions denominated RP1, RP2, RP3 and RP4. When these fractions were submitted to N-terminal sequencing, the comparative analysis in databanks revealed homology for two of these peptides, isolated from fractions RP3 and RP4, with sequences of proteinase inhibitors and 2S albumins, respectively. The F3 fraction, rich in peptides, inhibited the growth of yeasts Saccharomyces cerevisiae, Candida albicans, Candida parapsilosis, Candida tropicalis, Pichia membranifaciens, Kluyveromyces marxiannus and Candida guilliermondii. The RP3 and RP4 fractions showed high inhibitory activity against the growth of the yeast S. cerevisiae. The F3 fraction was also able to inhibit glucose-stimulated acidification of the medium by yeast cells of S. cerevisiae and to cause several morphological changes in different yeasts, such as cell wall disorganization, bud formation as well as the formation of pseudohyphae.

Antibacterial activity of extracts of six macroalgae from the northeastern Brazilian coast

Hexane, chloroform and ethanol extracts of six marine macroalgae (Rhodophyta and Chlorophyta) from North Ceará coast (Northeast Brazil) were evaluated for antibacterial activity by the single disk method. Best results were shown by the hexane extracts of Amansia multifida against enteric Gram-negative strains such as Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, S. Choleraesuis, Serratia marcescens, Vibrio cholerae and the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus.

Purification and physicochemical characterization of a cotyledonary lectin from Luetzelburgia auriculata.

A lectin was purified from the cotyledons of Luetzelburgia auriculata (Fr. All) Ducke by affinity chromatography on agarose-N-acetyl-D-galactosamine. The lectin is a potent agglutinin for rabbit erythrocytes, reacts with human red cells, but is inactive against cow, sheep, and goat erythrocytes. Hemagglutination of rabbit erythrocytes was inhibited by either 0.39 mM N-acetyl-neuraminic acid or N-acetyl-D-galactosamin, 12.5 mM D-lactose or D-melibiose, 50 mM D-galactose or raffinose. Its hemagglutinating activity was lost at 80 degrees C, 5 min, and the activation energy required for denaturation was 104.75 kJ mol(-1). Chromatography on Sephadex G-100, at pH 7.6, showed that at this hydrogenic ionic concentration the native lectin was a homotetramer (123.5 kDa). By denaturing SDS-PAGE, LAA seemed to be composed of a mixture of 29 and 15 kDa polypeptide subunits. At acidic and basic pHs it assumed different conformations, as demonstrated by exclusion chromatography on Superdex 200 HR 10/30. The N-terminal sequence of the 29 kDa band was SEVVSFSFTKFNPNQKDII and the 15 kDa band contained a mixture of SEVVSFSFTKFNPNQKDII and KFNQIVAVEEDTDXESQPQ sequences, indicating that these bands may represent full-length and its endogenous fragments, respectively. The lectin is a glycoprotein having 3.2% neutral carbohydrate, with a pI of 5.8, containing high levels of Asp+Asn and Glu+Gln and hydroxy amino acids, and low amount or absence of sulfur amino acids. Its absorption spectrum showed a maximum at 280 nm and a epsilon (1%) x (1cm) of 5.2. Its CD spectrum was characterized by minima near 228 nm, maxima near 196 nm and a negative to positive crossover at 210 nm. The secondary structure content was 6% alpha-helix, 8% parallel beta-sheet, 38% antiparallel beta-sheet, 17% beta-turn, 31% unordered and others contribution, and 1% RMS (root mean square). In the fluorescence spectroscopy, excitation of the lectin solution at 280 nm gave an emission spectrum in the 285-445 nm range. The wavelength maximum emission was in 334.5 nm, typical for tryptophan residues buried inside the protein.