The biofilm matrix of Pseudomonas sp. OX1 grown on phenol is mainly constituted by alginate oligosaccharides

The structure of the major constituent of the biofilm matrix produced by Pseudomonas sp. OX1, when grown on phenol as the sole carbon source is described. This investigation, carried out by chemical analysis, NMR spectroscopy and MALDI-TOF MS spectrometry, showed the presence of an oligosaccharide blend with the typical alginate structure, namely (1-->4) substituted beta-D-mannuronic (ManA) and alpha-L-guluronic acid (GulA). GulA residues were non-acetylated whereas ManA was always O-acetylated at C-2 or C-3

Structural characterization of syndiotactic propylene-styrene-ethylene terpolymers

The structural features of propylene-styrene-ethylene terpolymer (sP/(S-E)) prepd. using syndiospecific Cs-sym. metallocene catalyst, isopropylidene(cyclopentadienyl)-(9-fluorenyl)zirconium dichloride with MAO co-catalyst were studied. The polymorphism studies of as-prepd., melt-crystd., and fiber sP/(S-E) confirmed that ethylene units are mainly bound to styrene units arising from catalyst reactivation after the secondary insertion of styrene. Styrene-ethylene units are mainly segregated in the amorphous phase. The bulky styrene units, bound to ethylene, prevent the inclusion of ethylene units in the crystals of syndiotactic polypropylene (sPP), as generally occurs for copolymers of sPP with ethylene. This explains the fact that the effect of styrene-ethylene units on polymorphism of sPP is smaller than that obsd. in copolymers of sPP contg. only ethylene or butene comonomer units

Dinâmica da capacidade tecnológica ambiental: uma análise entre países desenvolvidos e em desenvolvimento (1990-2015)

The literature on national innovation systems highlights that investments in environmental innovation are influenced by the magnitude of the multidimensional characteristics of each economy. In order to build the possible bases for environmental technological development, countries need to advance in several issues related to scientific, technological, educational and health infrastructure. Thus, the article aims at investigating the evolution of different characterizations (developed and developing countries), in the period between 1990 and 2015. For that purpose, the methodology applied was Principal Component Analysis (PCA) and regression model with panel data. The results revealed that scientific characteristics and gas emissions were determining factors for the countries' innovative environmental performance over the years, especially developed ones. Furthermore, efforts were made by developing countries such as Brazil, China and India, in favor of a new environmental technological paradigm.A literatura sobre sistemas nacionais de inovação (SNIs) destaca que os investimentos em inovação ambiental são influenciados pela magnitude das características multidimensionais de cada nação. Para construírem as bases possíveis ao desenvolvimento tecnológico ambiental, os países precisam avançar em várias questões referentes à infraestrutura científica, tecnológica, educacional e sanitária. Nesse contexto, o presente artigo teve como objetivo investigar a evolução de diferentes características de 40 países (desenvolvidos e em desenvolvimento), no período de 1990 a 2015, considerando um conjunto de variáveis extraído dos bancos de dados da OCDE e do Banco Mundial. Para tanto, a metodologia aplicada baseou-se em Análise de Componentes Principais (ACP) e em um modelo de regressão com dados em painel. Os resultados revelaram que as características científicas e as emissões de gases foram fatores determinantes para o desempenho inovativo ambiental dos países, especialmente os países desenvolvidos, ao longo dos anos. Ademais, observou-se esforços dos países em desenvolvimento, como por exemplo, Brasil, China e Índia, em prol de um novo paradigma tecnológico ambiental

Estudo de pedal inteligente

O principal objetivo do trabalho foi aplicar o conhecimento inerente à área da Engenharia da Conceção e Desenvolvimento do Produto no desenvolvimento de um pedal de bicicleta inteligente. A informação relativa a áreas abordadas anteriormente e durante o desenvolvimento do projeto encontra-se inserida de forma a enquadrar o desenvolvimento do mesmo a nível de inovação e soluções aplicadas, tanto a nível material como tecnológico. O desenvolvimento do projeto e as suas etapas de parametrização tridimensional foram restringidos através de conhecimento científico e criativo, adveniente da pesquisa e desenvolvido durante o decorrer do projeto, presente em cada etapa específica, como elementos de suporte de tomada de decisões. Os processos de análise e prototipagem aplicados após a obtenção de um modelo tridimensional suficientemente estruturado, permitiram não só validar e analisar o trabalho executado a nível do corpo, como também retirar conclusões sobre o mesmo aperfeiçoando-o para a iniciação do projeto de moldes. O desenvolvimento relativo ao sistema validou a possibilidade de desenvolvimento e execução industrial do mesmo, através de experimentação e otimização das caraterísticas de maior relevância. Ao longo do trabalho estará presente a experimentação e adaptação de ferramentas criativas, analíticas e técnicas no desenvolvimento do projeto de forma a potenciar e adquirir soluções indicadas e cientificamente suportadas. Do desenvolvimento resultou a obtenção de modelos físicos e funcionais do pedal suficientemente restringidos e acabados em termos de Conceção e Desenvolvimento de Produto, para passarem a um âmbito de produção industrial

Molecular Structure of Endotoxins from Gram-negative Marine Bacteria: An Update

Marine bacteria are microrganisms that have adapted, through millions of years, to survival in environments often characterized by one or more extreme physical or chemical parameters, namely pressure, temperature and salinity. The main interest in the research on marine bacteria is due to their ability to produce several biologically active molecules, such as antibiotics, toxins and antitoxins, antitumor and antimicrobial agents. Nonetheless, lipopolysaccharides (LPSs), or their portions, from Gram-negative marine bacteria, have often shown low virulence, and represent potential candidates in the development of drugs to prevent septic shock. Besides, the molecular architecture of such molecules is related to the possibility of thriving in marine habitats, shielding the cell from the disrupting action of natural stress factors. Over the last few years, the depiction of a variety of structures of lipids A, core oligosaccharides and O-specific polysaccharides from LPSs of marine microrganisms has been given. In particular, here we will examine the most recently encountered structures for bacteria belonging to the genera Shewanella, Pseudoalteromonas and Alteromonas, of the γ-Proteobacteria phylum, and to the genera Flavobacterium, Cellulophaga, Arenibacter and Chryseobacterium, of the Cytophaga-Flavobacterium-Bacteroides phylum. Particular attention will be paid to the chemical features expressed by these structures (characteristic monosaccharides, non-glycidic appendages, phosphate groups), to the typifying traits of LPSs from marine bacteria and to the possible correlation existing between such features and the adaptation, over years, of bacteria to marine environments

Residue depletion and histopathological alterations in gilthead sea bream (Sparus aurata) after oral administration of oxytetracycline

Aquaculture is a key component of the animal food industry, but intensive farming conditions increase the incidence of infectious diseases. Oxytetracycline (OTC) plays a major role for infectious diseases in fishes. Its MRLs include their 4-epimers, so in this trial, the depletion of residues of OTC and 4-epioxytetracycline in muscle and liver have been evaluated in gilthead sea bream (Sparus aurata) after oral administration. Hepatotoxicity has been investigated with histopathological effects on target tissues. A validated DAD-HPLC with SPE extraction has been applied. Residual levels in muscle and liver depleted with a similar kel, but mean retention time and t½ß resulted longer in muscle than in liver because of different vascularization. The OTC concentrations were below the LMR at 48 h after dosing. No analytical peaks ascribable to 4-epi-OTC or other derivatives were detected, while histopathology of liver showed degenerated parenchymal hepatocytes, nuclear pyknosis, focal necrosis and inflammatory leucocytes infiltration. It can be concluded that the assessment of pharmacokinetic and residual depletion of antibiotics result fundamental to determine the most suitable therapeutic regime and to minimize the toxic effects in fish species

Isotactic and syndiotactic alternating ethylene/propylene copolymers obtained through non-catalytic hydrogenation of highly stereoregular cis-1,4 poly(1,3-diene)s

The homogeneous non-catalytic hydrogenation of cis-1,4 poly(isoprene), isotactic cis-1,4 poly(1,3-pentadiene) and syndiotactic cis-1,4 poly(1,3-pentadiene) with diimide, formed by thermal decomposition of para-toluenesulfonylhydrazide, is examined. Perfectly alternating ethylene/propylene copolymers having different tacticity (i.e., isotactic and syndiotactic), which are difficult to synthesize by stereospecific copolymerization of the corresponding monomers, are obtained. Both isotactic and syndiotactic alternating ethylene/propylene copolymers are amorphous, with very low glass transition temperatures

Human ESCs predisposition to karyotypic instability: Is a matter of culture adaptation or differential vulnerability among hESC lines due to inherent properties?

<p>Abstract</p> <p>Background</p> <p>The use of human embryonic stem cells (hESCs) in research is increasing and hESCs hold the promise for many biological, clinical and toxicological studies. Human ESCs are expected to be chromosomally stable since karyotypic changes represent a pitfall for potential future applications. Recently, several studies have analysed the genomic stability of several hESC lines maintained after prolonged <it>in vitro </it>culture but controversial data has been reported. Here, we prompted to compare the chromosomal stability of three hESC lines maintained in the same laboratory using identical culture conditions and passaging methods.</p> <p>Results</p> <p>Molecular cytogenetic analyses performed in three different hESC lines maintained in parallel in identical culture conditions revealed significant differences among them in regard to their chromosomal integrity. In feeders, the HS181, SHEF-1 and SHEF-3 hESC lines were chromosomally stable up to 185 passages using either mechanical or enzymatic dissection methods. Despite the three hESC lines were maintained under identical conditions, each hESC line behaved differently upon being transferred to a feeder-free culture system. The two younger hESC lines, HS181 (71 passages) and SHEF-3 (51 passages) became chromosomally unstable shortly after being cultured in feeder-free conditions. The HS181 line gained a chromosome 12 by passage 17 and a marker by passage 21, characterized as a gain of chromosome 20 by SKY. Importantly, the mosaicism for trisomy 12 gradually increased up to 89% by passage 30, suggesting that this karyotypic abnormality provides a selective advantage. Similarly, the SHEF-3 line also acquired a trisomy of chromosome 14 as early as passage 10. However, this karyotypic aberration did not confer selective advantage to the genetically abnormal cells within the bulk culture and the level of mosaicism for the trisomy 14 remained overtime between 15%–36%. Strikingly, however, a much older hESC line, SHEF-1, which was maintained for 185 passages in feeders did not undergo any numerical or structural chromosomal change after 30 passages in feeder-free culture and over 215 passages in total.</p> <p>Conclusion</p> <p>These results support the concept that feeder-free conditions may partially contribute to hESC chromosomal changes but also confirm the hypothesis that regardless of the culture conditions, culture duration or splitting methods, some hESC lines are inherently more prone than others to karyotypic instability.</p