Nature of Tasmanian oil shale

Since deposition, the organic matter of most oil shales has been so changed over geological time that little recognisable features remain. Microscopical examination does not provide much help for constitutional analysis and thus one cannot use biological features as a basis for classification. Tasmanite oil shale is a notable exception. The kerogen is so sharply differentiated from the mineral matrix that it can be largely separated by mechanical means. Tasmanite kerogen, when isolated, appears as flattened discs, which, by various sectioning processes, can be shown to have been nearly spherical in shape before compaction. There has been a great deal of argument as to the exact nature of these dissemenules. The century-old suggestion, originally rejected, that they are algal in origin has now been generally accepted and it may be taken that Tasmanites, as it occurs in oil shale, represents the cyst stage of a peculiar alga belonging, most likely, to the Chlorophyceae. The exact relationship within the family is still uncertain. Because of its discrete and peculiar structure, it might be assumed that the organic matter of tasmanite has a chemistry different from other algal shales. This is true only in so far as the soluble resin-like material is concerned, the pyrolysate possesses a normal hydrocarbon chemistry, although the non-hydrocarbon constituents are somewhat more than usual. Infrared and other physical methods of analysis support this hypothesis

The effects on grain quality traits of a grain serpin protein and the VPM 1 segment in southern Australian wheat breeding

Trabalho final do 6º ano médico com vista à atribuição do Grau de Mestre no âmbito do ciclo de estudos de mestrado integrado em medicina da Faculdade de Medicina de Coimbra.Introdução: Estudos prévios estabeleceram que até 12% dos doentes com enfarte agudo do miocárdio não demonstravam lesão coronária aparente ao exame angiográfico. Contudo, existe muito pouca informação disponível acerca deste fenómeno em enfartes agudos do miocárdio sem elevação do segmento ST. O objectivo deste estudo foi avaliar uma população de doentes com esse diagnóstico sujeitos a angiografia coronária, analisando e comparando as características clínicas e os prognósticos entre os que não revelaram lesão coronária aparente e os que apresentavam doença coronária epicárdica. Métodos: O nosso estudo avaliou 270 doentes com enfarte agudo do miocárdio sem elevação do segmento ST que foram sujeitos a angiografia coronária nas primeiras 72 horas de enfarte. Foram valorizadas as características demográficas, clínicas, parâmetros analíticos, achados electrocardiográficos, fracção de ejecção ventricular esquerda, duração do internamento e prognóstico.Previous studies established that up to 12% of patients with acute myocardial infarction did not present coronary atherosclerotic disease demonstrable with angiographic exam. However, little information is available about this phenomenon in acute non-STelevation myocardial infarction. We examined a population of patients with this diagnosis who had undergone coronary angiography, assessing and comparing the clinical characteristics and prognosis between the subset of patients with angiographically normal coronary arteries and the subset of patients with coronary disease

Circulating Strains of Human Respiratory Syncytial Virus in Central and South America

Human respiratory syncytial virus (HRSV) is a major cause of viral lower respiratory tract infections among infants and young children. HRSV strains vary genetically and antigenically and have been classified into two broad subgroups, A and B (HRSV-A and HRSV-B, respectively). To date, little is known about the circulating strains of HRSV in Latin America. We have evaluated the genetic diversity of 96 HRSV strains by sequencing a variable region of the G protein gene of isolates collected from 2007 to 2009 in Central and South America. Our results show the presence of the two antigenic subgroups of HRSV during this period with the majority belonging to the genotype HRSV-A2

Meiosis-Specific Stable Binding of Augmin to Acentrosomal Spindle Poles Promotes Biased Microtubule Assembly in Oocytes

In the oocytes of many animals including humans, the meiotic spindle assembles without centrosomes. It is still unclear how multiple pathways contribute to spindle microtubule assembly, and whether they are regulated differently in mitosis and meiosis. Augmin is a γ-tubulin recruiting complex which "amplifies" spindle microtubules by generating new microtubules along existing ones in mitosis. Here we show that in Drosophila melanogaster oocytes Augmin is dispensable for chromatin-driven assembly of bulk spindle microtubules, but is required for full microtubule assembly near the poles. The level of Augmin accumulated at spindle poles is well correlated with the degree of chromosome congression. Fluorescence recovery after photobleaching shows that Augmin stably associates with the polar regions of the spindle in oocytes, unlike in mitotic cells where it transiently and uniformly associates with the metaphase spindle. This stable association is enhanced by γ-tubulin and the kinesin-14 Ncd. Therefore, we suggest that meiosis-specific regulation of Augmin compensates for the lack of centrosomes in oocytes by actively biasing sites of microtubule generation within the spindle

Evolutionary distinctiveness of fatty acid and polyketide synthesis in eukaryotes

© 2016 International Society for Microbial Ecology All rights reserved. Fatty acids, which are essential cell membrane constituents and fuel storage molecules, are thought to share a common evolutionary origin with polyketide toxins in eukaryotes. While fatty acids are primary metabolic products, polyketide toxins are secondary metabolites that are involved in ecologically relevant processes, such as chemical defence, and produce the adverse effects of harmful algal blooms. Selection pressures on such compounds may be different, resulting in differing evolutionary histories. Surprisingly, some studies of dinoflagellates have suggested that the same enzymes may catalyse these processes. Here we show the presence and evolutionary distinctiveness of genes encoding six key enzymes essential for fatty acid production in 13 eukaryotic lineages for which no previous sequence data were available (alveolates: dinoflagellates, Vitrella, Chromera; stramenopiles: bolidophytes, chrysophytes, pelagophytes, raphidophytes, dictyochophytes, pinguiophytes, xanthophytes; Rhizaria: chlorarachniophytes, haplosporida; euglenids) and 8 other lineages (apicomplexans, bacillariophytes, synurophytes, cryptophytes, haptophytes, chlorophyceans, prasinophytes, trebouxiophytes). The phylogeny of fatty acid synthase genes reflects the evolutionary history of the organism, indicating selection to maintain conserved functionality. In contrast, polyketide synthase gene families are highly expanded in dinoflagellates and haptophytes, suggesting relaxed constraints in their evolutionary history, while completely absent from some protist lineages. This demonstrates a vast potential for the production of bioactive polyketide compounds in some lineages of microbial eukaryotes, indicating that the evolution of these compounds may have played an important role in their ecological success