Affine Lie algebraic origin of constrained KP hierarchies

An affine sl(n + 1) algebraic construction of the basic constrained KP hierarchy is presented. This hierarchy is analyzed using two approaches, namely linear matrix eigenvalue problem on hermitian symmetric space and constrained KP Lax formulation and it is shown that these approaches are equivalent. The model is recognized to be the generalized non-linear Schrödinger (GNLS) hierarchy and it is used as a building block for a new class of constrained KP hierarchies. These constrained KP hierarchies are connected via similarity-Bäcklund transformations and interpolate between GNLS and multi-boson KP-Toda hierarchies. Our construction uncovers the origin of the Toda lattice structure behind the latter hierarchy. © 1995 American Institute of Physics.

RFLP and cytogenetic evidence on the origin and evolution of allotetraploid domesticated peanut, Arachis hypogaea (Leguminosae)

Nuclear restriction fragment length polymorphism (RFLP) analysis was used to determine the wild diploid Arachis species that hybridized to form tetraploid domesticated peanut. Results using 20 previously mapped cDNA clones strongly indicated A. duranensis as the progenitor of the A genome of domesticated peanut and A. ipaensis as the B genome parent. A large amount of RFLP variability was found among the various accessions of A. duranensis, and accessions most similar to the A genome of cultivated peanut were identified. Chloroplast DNA RFLP analysis determined that A. duranensis was the female parent of the original hybridization event. Domesticated peanut is known to have one genome with a distinctly smaller pair of chromosomes ('A'), and one genome that lacks this pair. Cytogenetic analysis demonstrated that A. duranensis has a pair of 'A' chromosomes, and A. ipaensis does not. The cytogenetic evidence is thus consistent with the RFLP evidence concerning the identify of the progenitors. RFLP and cytogenetic evidence indicate a single origin for domesticated peanut in Northern Argentina or Southern Bolivia, followed by diversification under the influence of cultivation.

Phytochemical evidence for the plant origin of Brazilian propolis from Sao Paulo state

Propolis and plant secretions from three species, most frequently mentioned as botanical sources of the bee glue in Brazil (Baccharis dracunculifolia, Araucaria angustifolia and Eucalyptus citriodora) have been investigated using GC-MS. Based on chemical evidence, B. dracunculifolia was shown to be the main propolis source in Sao Paulo state. The antibacterial and antifungal activities of all four materials were also tested, the most active being propolis and Baccharis leaf exudate.

Geographical distribution and associated environments characterisation of catuba (Trichilia catigua A. Juss. - Meliaceae) in Paraná State - Brazil

Trichilia catigua A. Juss. - Meliaceae has been traditionally used as a tonic and digestive medicine. Some Brazilian pharmaceutical firms use this species to produce phytopharmaceuticals and alcoholic beverages. The aim of this work is to determine its geographical distribution and characterise the environments where catuaba is found in the state of Paraná, in order to support the domestication strategy for the agricultural production of this species. Based on the literature, botanical collections and field observations it was established, that five species of the genus occurring in Paraná, which were identified as T casaretti, T catigua, T claussenii, T elegans, T pallida and another supposed to be T pattens. Trichilia catigua occurs within a wide but defined strip in the state. By evaluating data of climate; soil types; natural vegetation formations; mean, maximum and minimum temperatures; relative humidity; rainfall; altitudes and evapotranspiration the strip may be localised above latitude 25° in the central and Eastern regions of the state and above latitude 26° in South-western Parana. In general, T catigua was found to occur on fertile, organic-matter-rich soils and predominantly under forest canopies.

The origin of lipid droplets in the post-pharyngeal gland of Dinoponera australis (Formicidae: Ponerinae)

The post-pharyngeal gland of normal and starvation ants was studied under TEM. This study showed an orgin of lipids droplets from mitochondria (named derivate mitochondria) in the normal ants and the lipids absence or reduction, in fasting ants.

Niche-specific association of Aeromonas ribotypes from human and environmental origin

A total of 88 Aeromonas isolates from distinct locations and sources (39 from extraintestinal infections, 31 from diarrhoeic, ten from non-diarrhoeic faeces, all human, and eight from fresh water) were subjected to phenospecies identification, serotyping, ribotyping and detection of some virulence markers. The strains belonged to four different phenospecies marked by 19 O serogroups and 38 ribotypes. No strong correlation between these parameters was found, and no group, as defined by the typing methods, could be characterized with a particular set of virulence markers. There was a clear association of ribotypes with the source of the strains. Cluster analysis allowed the identification of a complex of ribotypes belonging to distinct but related sources, including clinical and environmental isolates. These results suggest that ribotyping may be an epidemiological tool suitable for the study of Aeromonas infections.

Possible origin of RHIC Rout/Rsid HBT results

The effects of opacity of the nuclei together with a blackbody type of emission along the system history are considered as a means to explain the ratio Rout/Rsid observed by STAR and PHENIX collaborations at RHIC. Within our model, no flow is required to explain the data trend of this ratio for large surface emissivities. © 2003 Elsevier Science B.V. All rights reserved.

Genetic relatedness of Plasmodium falciparum isolates and the origin of allelic diversity at the merozoite surface protein-1 (MSP-1) locus in Brazil and Vietnam

Background: Despite the extensive polymorphism at the merozoite surface protein-1 (MSP-1) locus of Plasmodium falciparum, that encodes a major repetitive malaria vaccine candidate antigen, identical and nearly identical alleles frequently occur in sympatric parasites. Here we used microsatellite haplotyping to estimate the genetic distance between isolates carrying identical and nearly identical MSP-1 alleles. Methods: We analyzed 28 isolates from hypoendemic areas in north-western Brazil, collected between 1985 and 1998, and 23 isolates obtained in mesoendemic southern Vietnam in 1996. MSP-1 alleles were characterized by combining PCR typing with allele-specific primers and partial DNA sequencing. The following single-copy microsatellite markers were typed: Polyα, TA42 (only for Brazilian samples), TA81, TA1, TA87, TA109 (only for Brazilian samples), 2490, ARAII, PfG377, PfPK2, and TA60. Results: The low pair-wise average genetic distance between microsatellite haplotypes of isolates sharing identical MSP-1 alleles indicates that epidemic propagation of discrete parasite clones originated most identical MSP-1 alleles in parasite populations from Brazil and Vietnam. At least one epidemic clone propagating in Brazil remained relatively unchanged over more than one decade. Moreover, we found no evidence that rearrangements of MSP-1 repeats, putatively created by mitotic recombination events, generated new alleles within clonal lineages of parasites in either country. Conclusion: Identical MSP-1 alleles originated from co-ancestry in both populations, whereas nearly identical MSP-1 alleles have probably appeared independently in unrelated parasite lineages.

Bovine serum albumin displays luciferase-like activity in presence of luciferyl adenylate: Insights on the origin of protoluciferase activity and bioluminescence colours

Luciferyl adenylate, the key intermediate in beetle bioluminescence, is produced through adenylation of D-luciferin by beetle luciferases and also by mealworm luciferase-like enzymes which produce a weak red chemiluminescence. However, luciferyl adenylate is only weakly chemiluminescent in water at physiological pH and it is unclear how efficient bioluminescence evolved from its weak chemiluminescent properties. We found that bovine serum albumin (BSA) and neutral detergents enhance luciferyl adenylate chemiluminescence by three orders of magnitude, simulating the mealworm luciferase-like enzyme chemiluminescence properties. These results suggest that the beetle protoluciferase activity arose as an enhanced luciferyl adenylate chemiluminescence in the protein environment of the ancestral AMP-ligase. The predominance of luciferyl adenylate chemiluminescence in the red region under most conditions suggests that red luminescence is a more primitive condition that characterized the original stages of protobioluminescence, whereas yellow-green bioluminescence may have evolved later through the development of a more structured and hydrophobic active site. Copyright © 2006 John Wiley & Sons, Ltd.

Oral cancer mortality trends in Brazilian geographical regions from 1996-2001

The purpose of this study was to analyse the oral cancer mortality trends in Brazil by geographic region, age and sex, from 1996 to 2001. The Brazilian Ministry of Health database DATASUS and the Brazilian Institute of Geography and Statistics were used as the source of data. Oral cancer mortality rates per 100,000 population were estimated. Statistical analyses comprised estimates of oral cancer mortality rates, grouped according to the study variables, in 1996, 1997, 1998, 1999, 2000 and 2001; also, the three-year periods 1996-1998 and 1999-2001 were analysed, allowing the oral cancer mortality trends between these two periods to be calculated. For comparison, in each geographical region, the ratio between two death rates (related to period or sex) was calculated. In the period 1996-2001, a total of 25,972 deaths due to oral cancer were reported, giving a mortality rate of 2.67. The rates for the periods 1996-1998 and 1999-2001 were 2.53 and 2.73, respectively, showing a slight increase in the rate. There was a predominance of oral cancer in males with a male/female ratio of approximately 4. All regions exhibited an increase in mortality rates, with the exception of the Southeast region. From 1996 to 2001, the average mortality rates were 3.55 and 3.58 for the Southeast and South regions, and 1.94, 1.41, and 0.86 for the Mid-West, Northeast, and North regions, respectively. Over the age of 40, oral cancer mortality rates were seen to increase rapidly with age. Oral cancer mortality increased in all regions, except in the Southeast, and was considerably higher among males and older individuals.

Biosynthetic origin of the isoprene units in chromenes of Piper aduncum (Piperaceae)

Metabolic studies involving the incorporation of [1-13C]-D- glucose into intact leaves of Piper aduncum (Piperaceae) have indicated that both the mevalonate (MVA) and the pyruvate-triose (MEP) non-mevalonate pathways are implicated in the biosynthesis of isoprene moieties present in methyl 2,2-dimethyl-2H-1-chromene-6-carboxylate (1) and methyl 2,2-dimethyl-8- (3′-methyl-2′-butenyl)-2H-1-chromene-6-carboxylate (2). The pattern of incorporation of label from [1-13C]-D-glucose into these chromenes was determined by quantitative 13C NMR spectroscopy. The results confirmed that biosynthetic compartment of 1 and 2 could either be the plastid and/ or the cytosol or, possibly, an additional compartment such as the plastid inter-membrane space. ©2007 Sociedade Brasileira de Química.

The structural origin and biological function of pH-sensitivity in firefly luciferases

Firefly luciferases are called pH-sensitive because their bioluminescence spectra display a typical red-shift at acidic pH, higher temperatures, and in the presence of heavy metal cations, whereas other beetle luciferases (click beetles and railroadworms) do not, and for this reason they are called pH-insensitive. Despite many studies on firefly luciferases, the origin of pH-sensitivity is far from being understood. This subject is revised in view of recent results. Some substitutions of amino-acid residues influencing pH-sensitivity in firefly luciferases have been identified. Sequence comparison, site-directed mutagenesis and modeling studies have shown a set of residues differing between pH-sensitive and pH-insensitive luciferases which affect bioluminescence colors. Some substitutions dramatically affecting bioluminescence colors in both groups of luciferases are clustered in the loop between residues 223-235 (Photinus pyralis sequence). A network of hydrogen bonds and salt bridges involving the residues N229-S284-E311-R337 was found to be important for affecting bioluminescence colors. It is suggested that these structural elements may affect the benzothiazolyl side of the luciferin-binding site affecting bioluminescence colors. Experimental evidence suggest that the residual red light emission in pH-sensitive luciferases could be a vestige that may have biological importance in some firefly species. Furthermore, the potential utility of pH-sensitivity for intracellular biosensing applications is considered. © The Royal Society of Chemistry and Owner Societies.

Report of a chimeric origin of transposable elements in a bovine-coding gene

Despite the wide distribution of transposable elements (TEs) in mammalian genomes, part of their evolutionary significance remains to be discovered. Today there is a substantial amount of evidence showing that TEs are involved in the generation of new exons in different species. In the present study, we searched 22,805 genes and reported the occurrence of TE-cassettes in coding sequences of 542 cow genes using the RepeatMasker program. Despite the significant number (542) of genes with TE insertions in exons only 14 (2.6%) of them were translated into protein, which we characterized as chimeric genes. From these chimeric genes, only the FAST kinase domains 3 (FASTKD3) gene, present on chromosome BTA 20, is a functional gene and showed evidence of the exaptation event. The genome sequence analysis showed that the last exon coding sequence of bovine FASTKD3 is ∼85% similar to the ART2A retrotransposon sequence. In addition, comparison among FASTKD3 proteins shows that the last exon is very divergent from those of Homo sapiens, Pan troglodytes and Canis familiares. We suggest that the gene structure of bovine FASTKD3 gene could have originated by several ectopic recombinations between TE copies. Additionally, the absence of TE sequences in all other species analyzed suggests that the TE insertion is clade-specific, mainly in the ruminant lineage. ©FUNPEC-RP.

Origin of the circumflex branch of the coronary artery. A case report

The left coronary artery usually supplies the circumflex branch which provides several atrial and ventricular branches. During a routine dissection of the coronary artery, we could detect a circumflex branch originating from the right coronary artery. This resulted in an analysis of another 59 hearts without any similar results.

Chemical properties of different peats depending on origin and analytical method

The chemical properties of 12 different peats have been analyzed by methods from VDLUFA (German Association of Agricultural Analysis and Research Institutes) and EN (European Committee for Standardization, Technical Committee 223: Soil improvers and growing media). The analyses of pH (CaCl 2), contents of salts (H 2O), nutrients (CAT), and Na and Cl (H 2O) were carried out by VDLUFA methods, while those of pH (H 2O), EC (H 2O), nutrients (CAT), Na (CAT and H 2O) and Cl (H 2O) according to EN. Ten milled or sod white peats and two dredged frozen black peats of different degrees of decomposition were used. All of them contained high amounts of Mg, while black peats were additionally high in N, Fe and Zn. The pH-values were about the same for all peats. N- and Mn-contents depended most on peat origin. Analytical values of both CAT-methods were in the same range. Extraction with H 2O (EN) as compared to CAT (EN) resulted in considerably lower values.