DNA secondary structures and their contribution to mutagenesis in B. subtilis stationary phase cells

It is widely known and accepted that the cause of many mutations in cells are generated during the replication process of actively dividing cells, however more recent research has shown that mutations also arise in non growing conditions, a phenomenon known stationary phase mutagenesis. Much of what is known come from studies in eukaryotic and bacterial models. It is proposed that in nongrowing cells, the process of transcription plays an important role in mutagenesis. I will test the hypothesis that secondary structures formed of DNA generated transcription promote mutagenesis. The sequences transcriptiongenerated structures are speculated to be prone to mutations by exposing regions of single stranded DNA to lesions. To test this hypothesis, I examined the Bacillus subtilis gene thiF, predicted by in silico analysis to be prone to mutations at particular locations during transcription. By altering the base sequence of this gene, the stability of its stem-loop structures is affected, thereby allowing us to test whether transcription of the altered sequence influences accumulation of in thiF. Our assay for detection of mutations is based on reversion to thiamine auxotrophy in cells under conditions of starvation. Ultimately, these experiments will increase our understanding of how mutations occur in cells of all domains of life

Overview of the CLEF 2005 Interactive Track.

The CLEF Interactive Track (iCLEF) is devoted to the comparative study of user-inclusive cross-language search strategies. In 2005, we have studied two cross-language search tasks: retrieval of answers and retrieval of annotated images. In both tasks, no further translation or post-processing is needed after performing the tasks to fulfill the information need. In the interactive Question Answering task, users are asked to find the answer to a number of questions in a foreign-language document collection, and write the answers in their own native language. In the interactive image retrieval task, a picture is shown to the user, and then the user is asked to find the picture in the collection. This paper summarizes the task design, experimental methodology, and the results obtained by the research groups participating in the track

Mortality in Belarus, Lithuania, and Russia: divergence in recent trends and possible explanations

Before the collapse of the Soviet Union, Belarus, Lithuania, and Russia were quite comparable in terms of their socioeconomic development. Despite some differences in overall mortality levels, the three former Soviet republics were also very close to each other in terms of directions of mortality trends and age- and cause-specific mortality patterns. After 1991, all the three countries experienced substantial political and social transformations, and the challenges associated with the transition from a socialist to a market economy system. The sudden changes brought numerous problems, such as rapid growth in unemployment, falling standards of living, and growing social and income inequalities. These factors contributed to the significant deterioration of the health situation in all the countries, but the size and the nature of the mortality crisis was different in Belarus than it was in Lithuania and Russia. The marked similarities in socioeconomic and mortality trends in the countries up to 1991 contrast with their notable divergence during the subsequent years. The nature and success of market reforms seems to be the most plausible explanation for these differences. Russia and Lithuania have chosen more radical forms of economic and political transformations, which have led to massive privatization campaigns. The reforms were more sustainable and systematic in Lithuania than in Russia. By contrast, Belarus has chosen a gradual and slow transition path. Recent mortality trends in Belarus are explored in detail here, and are contrasted with those observed in Lithuania and Russia. Including a cause-of-death analysis sheds more light on the plausible determinants of the variations in mortality levels between the countries.Avant la chute de l’Union Soviétique, la Biélorussie, la Lituanie et la Russie étaient tout à fait comparables en termes de développement socio-économique. En dépit de quelques différences de taux de mortalité générale, les ex-Républiques Soviétiques étaient également très proches en termes de tendances et de variations de la mortalité par cause et par âge. Après 1991, les 3 pays ont connu des bouleversements politiques et sociaux, et ont dû faire face aux défis associés au passage d’une économie socialiste à l’économie de marché. Ces changements soudains ont provoqué de nombreux problèmes, tels qu’une montée rapide du chômage, la baisse du niveau de vie et le développement d’inégalités sociales et de revenu. L’ensemble de ces facteurs a contribué à une détérioration significative de la situation sanitaire dans tous les pays, mais la crise de mortalité en Biélorussie était différente de celles de la Lituanie et de la Russie, à la fois en termes d’étendue et de nature. Les grandes similitudes des tendances socio-économiques et de mortalité dans ces pays jusqu’en 1991 contrastent avec leur divergence notable au cours des années qui ont suivi. La nature et le succès des réformes liées au passage à l’économie de marché est l’explication la plus plausible de ces différences. La Russie et la Lituanie ont choisi des formes plus radicales de transformation économique et politique, qui ont mené à des campagnes de privatisation massives. Les réformes étaient plus durables et systématiques en Lituanie qu’en Russie. La Biélorussie, en revanche, a choisi la voie d’une transformation graduelle et lente. Les tendances récentes de la mortalité en Biélorussie sont examinées en détail dans cette étude, et comparées à celles observées en Lituanie et en Russie. Une analyse des causes de décès éclaire sur les déterminants plausibles des variations de niveau de mortalité entre ces pays

Marginal Eyespots on Butterfly Wings Deflect Bird Attacks Under Low Light Intensities with UV Wavelengths

Predators preferentially attack vital body parts to avoid prey escape. Consequently, prey adaptations that make predators attack less crucial body parts are expected to evolve. Marginal eyespots on butterfly wings have long been thought to have this deflective, but hitherto undemonstrated function.Here we report that a butterfly, Lopinga achine, with broad-spectrum reflective white scales in its marginal eyespot pupils deceives a generalist avian predator, the blue tit, to attack the marginal eyespots, but only under particular conditions-in our experiments, low light intensities with a prominent UV component. Under high light intensity conditions with a similar UV component, and at low light intensities without UV, blue tits directed attacks towards the butterfly head.In nature, birds typically forage intensively at early dawn, when the light environment shifts to shorter wavelengths, and the contrast between the eyespot pupils and the background increases. Among butterflies, deflecting attacks is likely to be particularly important at dawn when low ambient temperatures make escape by flight impossible, and when insectivorous birds typically initiate another day's search for food. Our finding that the deflective function of eyespots is highly dependent on the ambient light environment helps explain why previous attempts have provided little support for the deflective role of marginal eyespots, and we hypothesize that the mechanism that we have discovered in our experiments in a laboratory setting may function also in nature when birds forage on resting butterflies under low light intensities

The Pharmacological Effect Of Bothrops Neuwiedii Pauloensis (jararaca-pintada) Snake Venom On Avian Neuromuscular Transmission.

The neuromuscular effects of Bothrops neuwiedii pauloensis (jararaca-pintada) venom were studied on isolated chick biventer cervicis nerve-muscle preparations. Venom concentrations of 5-50 micro g/ml produced an initial inhibition and a secondary increase of indirectly evoked twitches followed by a progressive concentration-dependent and irreversible neuromuscular blockade. At venom concentrations of 1-20 micro g/ml, the responses to 13.4 mM KCl were inhibited whereas those to 110 micro M acetylcholine alone and cumulative concentrations of 1 micro M to 10 mM were unaffected. At venom concentrations higher than 50 micro g/ml, there was pronounced muscle contracture with inhibition of the responses to acetylcholine, KCl and direct stimulation. At 20-24 degrees C, the venom (50 g/ml) produced only partial neuromuscular blockade (30.7 +/- 8.0%, N = 3) after 120 min and the initial inhibition and the secondary increase of the twitch responses caused by the venom were prolonged and pronounced and the response to KCl was unchanged. These results indicate that B.n. pauloensis venom is neurotoxic, acting primarily at presynaptic sites, and that enzyme activity may be involved in this pharmacological action.36617-2

Relationships between physiological characteristics and trace metal body burdens of banded garden spiders Argiope trifasciata (Araneae, Araneidae)

Banded garden spiders (Argiope trifasciata) were collected at the Ballona Wetlands, a metal contaminated salt marsh. The relationship between spider body size and individual metal loads was investigated. Biochemical markers were identified in spider fecal material and found to correlate to body metal levels. Body metal dry weight concentrations of Cd, Cr, Cu, Zn and total metals in female A. trifasciata exhibited distinct patterns of spatial and annual variation during 2006 and 2007. Spider body size was homogeneous across sites in both years, while increased Cd and Cr concentrations were sometimes associated with a reduction in spider size, though the influence of Cr was quite minor. Spiders with higher body Cu levels showed a reduction in peak area for hypoxanthine and an un-identified component in fecal material chromatograms. Spatial and annual differences in metal bioaccumulation are likely mediated by variation in site-specific environmental parameters and rainfall, while the negative relationships between body size and metal levels are presumably a consequence of a spider\u27s expenditure of energy for metal tolerance mechanisms vs. foraging and growth. Finally, correlating body metal levels with excreta products constitutes a novel method to non-invasively predict metal levels in spiders

how useful are the causes of death when extrapolating mortality trends an update

Old age and adult mortality have over the last decades enjoyed a remarkable decline throughout the western world, posing the researcher with new challenges and opening up fresh horizons in life expectancy trends. The recent drop in mortality may be largely traced to the unexpected decline in cardiovascular diseases and certain cancers. Thus it could be hoped that in the future these trends would continue and extend to include other causes where, for the moment, little change has occurred. Such a hypothesis is all the more realistic in view of the fact that recent changes are linked, not just to advances in more efficacious medical treatment, but also to a growing awareness on the part of the general public regarding questions of health and the crucial role played by life style and behaviour. These include improved dietary habits, for example, a better attitude to risk factors, particularly to smoking, alcohol abuse, dangerous driving, etc. This awareness, which prevails among more recent, well-informed and better educated cohorts, not only produces immediate results, but maybe even more so in the future, should this spare coming generations the accumulation of risks which were and continue to be the burden particularly of older cohorts

Designing and implementing an assay for the detection of rare and divergent NRPS and PKS clones in European, Antarctic and Cuban soils

The ever increasing microbial resistome means there is an urgent need for new antibiotics. Metagenomics is an underexploited tool in the field of drug discovery. In this study we aimed to produce a new updated assay for the discovery of biosynthetic gene clusters encoding bioactive secondary metabolites. PCR assays targeting the polyketide synthases (PKS) and non-ribosomal peptide synthetases (NRPS) were developed. A range of European soils were tested for their biosynthetic potential using clone libraries developed from metagenomic DNA. Results revealed a surprising number of NRPS and PKS clones with similarity to rare Actinomycetes. Many of the clones tested were phylogenetically divergent suggesting they were fragments from novel NRPS and PKS gene clusters. Soils did not appear to cluster by location but did represent NRPS and PKS clones of diverse taxonomic origin. Fosmid libraries were constructed from Cuban and Antarctic soil samples; 17 fosmids were positive for NRPS domains suggesting a hit rate of less than 1 in 10 genomes. NRPS hits had low similarities to both rare Actinobacteria and Proteobacteria; they also clustered with known antibiotic producers suggesting they may encode for pathways producing novel bioactive compounds. In conclusion we designed an assay capable of detecting divergent NRPS and PKS gene clusters from the rare biosphere; when tested on soil samples results suggest the majority of NRPS and PKS pathways and hence bioactive metabolites are yet to be discovere

Long-term trends in the longevity of scientific elites: evidence from the British and the Russian academies of science.

National science academies represent intellectual elites and vanguard groups in the achievement of longevity. We estimated life expectancy (LE) at age 50 of members of the British Royal Society (RS) for the years 1670-2007 and of members of the Russian Academy of Sciences (RAS) for the years 1750-2006. The longevity of academicians was higher than that of their corresponding national populations, with the gap widening from the 1950s. Since the 1980s, LE in the RS has been higher than the maximum LE among all high-income countries. In each period, LE in the RS was greater than in the RAS, although since the 1950s it has risen in parallel in the two academies. This steep increase shared by academicians in Britain and Russia suggests that general populations have the potential for a substantial increase in survival to high ages