Recolha de amostras de solo nas ilhas das Flores e Corvo para isolamento de bactérias entomopatogénicas

XIII Expedição Científica do Departamento de Biologia - Flores e Corvo 2007.Durante a XIII Expedição Científica do Departamento de Biologia às ilhas das Flores e Corvo em 2007 recolheram-se amostras de solo e água a diferentes altitudes e com diversos cobertos vegetais, (78 na Ilha das Flores e 25 na Ilha do Corvo), as quais foram transportadas para o laboratório de Entomopatologia para isolamento de bactérias entomopatogénicas. Destas 103 amostras obtivemos 509 isolados puros, 275 destes pertencentes ao Grupo Bacillus cereus, onde se enquadra o Bacillus thuringiensis. Estes isolados estão a ser identificados a nível da espécie por métodos bioquímicos e moleculares. No entanto, até à presente data, obtiveram-se apenas 7 isolados de Bacillus thuringiensis provenientes do Corvo. Todos os isolados estão depositados no Banco de Bactérias Entomopatogénicas dos Açores / Centro de Investigação do Recursos Narurais (BEA/CIRN)

Bactéria isolada nos Açores produz celulase com potencial biotecnológico

A secção Biologia é coordenada pelo Professor Universitário Armindo Rodrigues.Uma das áreas de actividade da biotecnologia é a pesquisa de enzimas que possam ser usadas em processos industriais. O uso destas enzimas substitui muitas vezes processos muito poluentes e consumidores de energia. Porém, estas enzimas para serem úteis têm de ter propriedades muito particulares, por exemplo funcionarem a temperaturas muito altas ou a pH extremos (ácidos ou alcalinos). Muitas destas enzimas são obtidas de microorganismos que evoluíram e se adaptaram de modo a viver em condições ambientais limite da vida. Os ambientes vulcânicos estão entre estes ambientes extremos e por isso despertam interesse na procura de moléculas que apresentem modificações em relação as normalmente encontradas e que sejam activas justamente nas condições em que muitas vezes a indústria necessita que funcionem. Tem-se mostrado que nos Açores existem locais com uma grande riqueza em microorganismos extremófilos. O Grupo de Biotecnologia Microbiana da Universidade dos Açores (GBM-UAc) tem colecções de bactérias que foram isoladas de diferentes locais dos Açores, tais como solos (vulcânicos), fumarolas, fontes termais terrestres e marinhas de baixa profundidade, etc. As amostras destes diferentes locais são trazidas para o laboratório e tratadas de modo a isolar bactérias aí existentes. […].info:eu-repo/semantics/publishedVersio

Synthesis of graphene by electrochemical exfoliation from petroleum coke for electrochemical energy storage application

The objective of the present work was to synthesize a graphene-like structure from petroleum coke (pet coke). Graphene is a potential alternative conducting material to replace traditional electrode materials such as indium tin oxide. The phosphoric acid was used to activate the pet coke in conditions where the coke to acid ratio is varied as 1:1, 1:2, 1:3, 1:4 and 1:5. The samples were kept at different temperatures in the furnace maintained in inert atmospheric conditions at 400, 500 and 600 °C for activation time intervals of 1, 2 and 3 h. The extent of activation of pet coke samples was characterized by their yield and iodine number. For the optimized conditions (600 °C, 3 h, 1:4 coke to acid ratio), the activated pet coke was moulded and taken as the anode for electrochemical exfoliation using platinum wire as cathode, and 0.3 M H2SO4 solution as electrolyte. The electrochemical exfoliation was carried out using DC power supply at 22 V for 8 h, and the obtained exfoliated product was analysed by surface-sensitive techniques (XRD, Raman and SEM). The specific capacitance values were measured using cyclic vol­tammetry in KOH, Na2SO4 and H2SO4 electrolytes. The highest specific capacitance value of 40 F g-1 for the scanning rate of 25 mV s-1 was obtained in 1 M H2SO4. It was confirmed that graphene-like structure produced from activated pet coke can be used as an alternate material for supercapacitor applications

Nitrogen doped graphene supported Pt-Pd nanoparticle modified GC electrode for electrochemical determination of tramadol and paracetamol

The role of functionalized nitrogen doped graphene (NGp) using poly(diallyldimethylammonium chloride) (PDDA) as modified electrode has been discussed. Pt-Pd bimetallic nanoparticles have been anchored on PDDA-NGp to form PtPd-PDDA-NGp nanocomposites, which are characterized by high resolution transmission electron microscope, X-ray diffraction and Raman spectroscopy. The simultaneous determination of paracetamol and tramadol has been carried out using the nitrogen doped graphene supported Pt-Pd nanoparticle modified glassy carbon electrode in 0.1 M Britton-Robinson buffer solution (pH 5.0). Two well-defined voltammetric peaks are obtained in square wave voltammogram measurements. It has been observed that the modified electrode can detect a wide linear range of concentrations of paracetamol from 5×10-6 to 1×10-4 M, and tramadol from 1.2×10-5 to 2.4×10-4 M. The limit of detection was found to be 1.8×10-7 and 5.7×10-6 M for paracetamol and tramadol, respectively (S/N = 3)

GC-MS-based metabolomics analysis unravels the therapeutic potential of Neolamarckia cadamba fruit peel

Kadam (Neolamarckia cadamba (Roxb.) is an evergreen tropical tree widely grown in Asia, particularly in India. Neolamarckia cadamba commonly known as kadam, cadamba or burflower tree. The roots, leaves, barks, and fruits of N. cadamba possess medicinal properties and are commonly used in the pharmaceutical industry. Fruit peels are the main waste and may contain various biologically active compounds. However, no prior knowledge about the therapeutic compounds of the peel. The objective of the present study was to unveil therapeutic compounds from the peel by Gas Chromatography–Mass Spectrometry (GC-MS) based metabolomics analysis. Metabolites from the kadam fruit peel were isolated and derivatized using MSTFA, characterized by the GC-MS analysis. Raw spectral data were pre-processed, and peak identification was performed using SHIMADZU Postrun analyse software. The metabolites in N. cadamba fruit peel were identified by comparing the peaks with the mass spectral reference database NIST v20. The results showed that the peel of kadam fruit contains 149 metabolites, which were further categorized into 46 different metabolite classes, with 52 different metabolic pathways and 63 biological functions. The principal roles of the metabolites were identified by functional annotation and enrichment analysis. It revealed that metabolites were responsible for anti-inflammation, anti-oxidant, anti-microbial, and anti-cancer properties. In summary, the peel of kadam fruit also contains various therapeutic compounds like other cadamba parts (i.e., roots, leaves, barks, and fruits). Further, comparing the peel with other parts discloses the peel-specific metabolites. The results obtained in this study could be useful for the pharmaceutical industry

Molecular Cloning and Docking of speB Gene Encoding Cysteine Protease With Antibiotic Interaction in Streptococcus pyogenes NBMKU12 From the Clinical Isolates

Streptococcus pyogenes causes a variety of diseases ranging from mild diseases to severe invasive infections which result in significant morbidity and mortality. This study focuses on the antibiotic resistance of S. pyogenes and their interaction with cysteine protease. Around 36 beta-hemolytic isolates were collected from the clinical lab, of which seven isolates (19.4%) were identified as Streptococcus pyogenes. One of the seven isolates was collected from a urinary tract infection, which was identified by antibody agglutination and MALTI-TOF-MS, and it is designated as S. pyogenes NBMKU12. Around 8.3 to 66.6 % of the isolates were found to be resistant to one or more antimicrobial agents, especially, penicillin-G resistance was exhibited by 29.1% of the isolates. In the NBMKU12 isolate, the beta lactem (TEM) gene was detected among the 13 antibiotic genes for which it was tested. Furthermore, when analysis for presence of 13 virulence genes were carried out in NBMKU12 isolate, only speJ and speB were detected. The speB (streptococcal pyrogenic exotoxin B) encoding cysteine protease gene was cloned. This was followed by performing DNA sequencing to understand the putative cysteine protease interaction with antibiotics, inhibitors, and substrate. The speB gene consists of 1197 nucleotides and encodes a protein with multiple domains, including a signal peptide (aa 1–22), an inhibitor region (aa 27–156), and a catalytic cysteine domain (aa 160–367). The signal peptide cleavage site is predicted between Ala22 and Asn23. The putative 398 amino acid residues were found to have a theoretical pI of 8.76 and a molecular mass of 43,204.36 Da. The tested culture supernatants of NBMKU12 isolate exhibited the proteolytic activity against casein, papaya and pineapple used as substrates. The proteolytic activity suggests the expression of speB gene. Molecular docking analysis of cysteine protease showed that erythromycin (bond length 2.41 Å), followed by chloramphenicol (2.51 Å), exhibited a strong interaction; while penicillin-G (3.24 Å) exhibited a weak interaction, and this factor could be considered as a cause for penicillin-G resistance. The present study contributes to a better understanding of speB gene encoding cysteine protease, antibiotic resistance, and their interaction in the isolate, S. pyogenes NBMKU12. The antibiotics and cysteine protease interaction study confirms the resistance or sensitivity of S. pyogenes. Hence, it could be hypothesized that the isolate NBMKU12 is resistant to most of the tested antibiotics, and this resistance might be a cause for mutation

Impedance behaviour of some copper alloys and monel in synthetic sea water

The corrosion behaviour of monel, admiralty brass, a!uminium brass, 70Cu- 30Ni and WCu-1ONi alloys in sea water has been evaluated by impedance method for a frequency range of lmHz to 10KHz. It has been found that monel exhib-its superior corrosion resistance owing to the formation of compact film. In the case of other alloys, the formation of porous corrosion product film protects the metal from dissolutio