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PubMed2004

Evolutionary mode, tempo, and phylogenetic association of continuous morphological traits in the aquatic moss genus Amblystegium.

Evolutionary significance of morphological characters that have traditionally been used for species delineation in the aquatic moss genus Amblystegium was tested by partitioning the environmentally and genetically induced morphological variation and focusing on morphological evolution using comparative methods. Cultivation experiments under controlled condition showed that most of the morphological variation in nature resulted from plasticity. Information regarding genetically fixed morphological variation and genetic similarity derived from polymorphic inter-simple sequence repeat markers was combined into an explicit model of morphological evolution. Maximum likelihood estimates of the model parameters indicated that evolution of most characters tended to accelerate in the most recent taxa and was often independent from the phylogeny. Constraining the different characters to be independent from each other most often produced a less likely result than when the characters were free to evolve in a correlated fashion. Thus, the morphological characters that have traditionally been used to circumscribe different Amblystegium species lack the independence, diagnostic value for specific lineages, and stability that would be required for distinguishing different species.

Analysis of Variance↗
PubMed1992

[Brucellosis: a clinico-serological study in a rural health area].

UNLABELLED: We analyze retrospectively 132 cases of brucellosis evaluating the performance of diagnostic procedures, complications and serological and clinical evolution. We compare the 74 patients treated with streptomycin plus tetracycline versus the 41 patients treated with doxycycline plus rifampicin. The more outstanding results we find: a) Great sensibility of the rose bengal test; b) Higher relapse rate in the more severe cases (p less than 0.01); c) Good evolution with scarce relapse rate in both treatment groups; agglutination titers were lower at one year in the group treated with doxycycline plus rifampicin (p less than 0.05). CONCLUSIONS: Both treatments showed good efficacy, controlled studies would be needed to determine the most adequate one.

Age Factors↗
PubMed1999

Gene order breakpoint evidence in animal mitochondrial phylogeny.

Multiple genome rearrangement methodology facilitates the inference of animal phylogeny from gene orders on the mitochondrial genome. The breakpoint distance is preferable to other, highly correlated but computationally more difficult, genomic distances when applied to these data. A number of theories of metazoan evolution are compared to phylogenies reconstructed by ancestral genome optimization, using a minimal total breakpoints criterion. The notion of unambiguously reconstructed segments is introduced as a way of extracting the invariant aspects of multiple solutions for a given ancestral genome; this enables a detailed reconstruction of the evolution of non-tRNA mitochondrial gene order.

Animals↗
PubMed2006

Corticobasal degeneration and progressive aphasia.

OBJECTIVE: To describe language impairment in the corticobasal degeneration syndrome (CBDS) presenting as either a cognitive or motor disorder, to compare the evolution of aphasia in CBDS with primary progressive aphasia (PPA), and to examine whether the side of maximal cerebral atrophy or akinesia reflects the severity of aphasia. METHODS: We divided 40 patients with CBDS according to motor or cognitive onsets and conducted detailed language assessments with the Western Aphasia Battery (WAB). We analyzed scores according to the side of atrophy and motor rigidity. Longitudinal performance over three annual assessments was compared against matched patients with PPA and Alzheimer disease. RESULTS: Language at baseline was more impaired in cognitive than motor-onset CBDS but there was no correlation between the side of atrophy or motor impairment and the WAB. Serial assessment (n = 19) showed a similar evolution of aphasia in cognitive-onset CBDS and PPA and delayed aphasia in motor-onset CBDS. CONCLUSION: Aphasia is common in the corticobasal degeneration syndrome but there is little correlation with the laterality of clinical deficits. Cognitive-onset corticobasal degeneration syndrome and primary progressive aphasia are similar such that their aphasia appears identical.

Aged↗
PubMedDate not supplied

Demonstration of the neutrophil granulocyte functional capacity in silicosis, using the NBT test.

The functional capacity of neutrophils was studied using the NBT test in 68 patients with silicosis in various evolutive stages, comparatively with a group of 35 controls. The NBT test showed an initial increase of nonspecific cellular reactivity which decreased as the disease evolved. The results in the control group showed 9 +/- 5% NBT positive neutrophils. The highest proportion of NBT positive neutrophils (17.6 +/- 2.3, p < or = 0.05) was found in stage I of the disease and then decreased gradually with the evolution of the disease. The proportion of NBT positive neutrophils may be considered as a biochemical marker of neutrophil functionality.

Biomarkers↗
PubMed1996

Detecting non-neutral heterogeneity across a region of DNA sequence in the ratio of polymorphism to divergence.

Natural selection, in the form of balancing selection or selective sweeps, can result in a decoupling of the amounts of molecular polymorphism and divergence. Thus natural selection can cause some areas of DNA sequence to have greater silent polymorphism, relative to divergence between species, than other areas. It would be useful to have a statistical test for heterogeneity in the polymorphism to divergence ratio across a region of DNA sequence, one that could identify heterogeneity greater than that expected from the neutral processes of mutation, drift, and recombination. The only currently available test requires that a region be arbitrarily divided into sections that are compared with each other, and the subjectivity of this division could be problematic. Here a test is proposed in which runs of polymorphic and fixed sites are counted, where a "run" is a set of one or more sites of one type preceded and followed by the other type. The number of runs is smaller than otherwise expected if polymorphisms are clumped together. By simulating neutral evolution and comparing the observed number of runs to the simulations, a statistical test is possible which does not require any a priori decisions about subdivision.

Animals↗
PubMed1982

An unusual evolutionary behaviour of a sea urchin histone gene cluster.

DNA sequences of cloned histone coding sequences and spacers of sea urchin species that diverged long ago in evolution were compared. The highly repeated H4 and H3 genes active during early embryogenesis had evolved (in their silent sites) at a rate (0.5-0.6% base changes/Myr) similar to single-copy protein-coding genes and nearly as fast as spacer DNA (0.7% base changes/Myr) and unique DNA. Thus, evolution in the major histone genes conforms to a universal evolutionary clock based on the rate of base sequence change. By contrast, the H4 and H3 coding sequences and a non-transcribed spacer of the DNA clone h19 of Psammechinus miliaris show an exceptionally low rate of sequence evolution only 1/100 to 1/200 that predicted from the clock hypothesis. According to the classical model of gene inheritance, the h19 DNA sequences in the Psammechinus genome require unusual conservation mechanisms by selection at the level of the gene and spacer sequences. An alternative explanation could be recent horizontal gene transfer of a histone gene cluster from the very distantly related Strongylocentrotus dröbachiensis to the P. miliaris genome.

Journal Article↗
PubMed1995

[The impact of AIDS in the global mortality in Catalonia, 1981-1993].

OBJECTIVES: To compare the evolution of the principal causes of death in Catalonia, Spain and to assess the impact of AIDS as a contributing factor to the increase of mortality in young people in Catalonia. METHODS: Data from the mortality register of Department of Health in Catalonia has been used. We have compared the principal causes of death in Catalonia for the global population and for the group of 20 to 39 year olds. We have calculated the potential years of life lost (PYLL) between the ages of 13 to 65. RESULTS: Since the first case of AIDS in 1981, AIDS has been the cause of death with the most important increase for the global population in Catalonia. AIDS is the sixth cause of death and the first cause of PYLL. For the young population in Catalonia (aged 20-39) AIDS became, in 1993, the first cause of death. From 1992 to 1993 the PYLL due to AIDS increased 5% in men and 51% in women. CONCLUSIONS: The present situation has led AIDS being the first cause of death among young population. The collaboration between mortality registers and AIDS registers is absolutely essential to assess more accurately the impact of AIDS on the mortality of population.

Acquired Immunodeficiency Syndrome↗
PubMed1993

[The effect of respiratory rehabilitation on the functional ventilation changes in the asthmatic child].

UNLABELLED: The aim of this study was to evaluate the improvement of lung function abnormalities during asymptomatic periods in children with perennial atopic asthma after physical respiratory rehabilitation and swimming (RR). MATERIAL AND METHODS: 240 lung function tests were performed regularly by whole-body plethysmography during asymptomatic periods on 68 atopic asthmatic children aged 5-13 (means 8.7 y), in a follow up four years study (1983-87). TLC, VC, FEV1, Raw, MEF50, RV and TGV were recorded. We selected TGV for measured hyperinflation, Resistance (Raw) for bronchial obstruction and MEF50 for small airways obstruction. We divided these children population in two groups: group A control (20 subjects, means 9.3 y. age) immunotherapy (IT) alone; group B (48 subjects, means 8.03 y. age) IT and respiratory rehabilitation and swimming. Furthermore, we compared the evolution of the lung function according to the severity of asthma on B group alone. RESULTS: the number of hyperinflated or bronchial obstructed children who did RRS is significantly smaller than on the control group. Nevertheless, breathing exercises and swimming has no effect on peripheral airway obstruction. When we compared the effect of asthma on B group alone, we noted that the recovery of lung abnormalities were observed on the great majority of mild and moderate hyperinflated and bronchial obstructed asthma. In severe asthma, the results were not so good, particularly on bronchial and peripheral airway obstruction. In these last cases the functional prognosis will be uncertain. CONCLUSION: respiratory rehabilitation and swimming have an unquestionable effect on improvement of hyperinflated asthmatic children, some effect on improvement on permanent bronchial obstruction, and without any benefit on permanent peripheral airway obstruction. Lung function tests might be monitored the RR in all asthmatic children with lung function impairment.

Adolescent↗
PubMed2026

Comparative analysis of conserved non-coding elements identifies gene regulatory networks rewired during the water-to-land transition in vertebrates.

The conquest of land by vertebrates has been a pivotal moment in evolutionary history. Adapting to the new habitats necessitated numerous changes in vertebrate anatomy and physiology, creating an enduring imprint on the developmental gene regulatory networks (GRNs) of tetrapods. The increase of high-quality genomic resources over the past decade has made it possible to study the genomic legacy of the water-to-land transition. While much attention has been given to the highly conserved non-coding elements (CNEs) of the genome that share high levels of similarity across evolutionarily diverged clades, recent evidence suggests that perhaps comparable attention should be given to "missing" CNE-s, conserved sequence patches present in extant stem gnathostomes and actinopterygian fishes that have become undetectable in tetrapods during the adaptation to terrestrial life, whether through true sequence loss or divergence beyond alignability. These sequences could help us reveal the relaxation of certain developmental constraints, related to the aquatic lifestyle, that made reaching new adaptive peaks in the developmental landscape possible. In this paper, we search for such CNEs and characterize them in comparison with pan-Gnathostome CNEs, using the zebrafish (Danio rerio) genome as a reference. Our results suggest that the rewiring of developmental networks related to pigmentation and muscle structure formation has left the largest genomic imprint. We also find that components of canonical Wnt and Hedgehog signalling, are enriched among CNEs retained in fish.

cis-regulatory evolution↗
PubMed1986

Globin evolution in the genus Xenopus: comparative analysis of cDNAs coding for adult globin polypeptides of Xenopus borealis and Xenopus tropicalis.

Globin mRNAs of Xenopus borealis and Xenopus tropicalis have been cloned and sequenced. The nucleotide and derived amino acid sequences were compared with each other and with already available data from Xenopus laevis. This analysis rendered clear evidence that the common ancestor of X. laevis and X. borealis, but not of X. tropicalis, had lost one amino acid of the beta-globins prior to a genome duplication event that preceded the segregation of the former two species. Replacement-site substitutions were used to calculate a rough time scale of genome duplication and species segregation. The results suggest an ancient separation between the X. laevis and the X. tropicalis groups occurring approximately 110-120 million years ago. Analysis of the amino acid chains demonstrated various alterations. However, some functional domains, like heme-binding sites and alpha 1 beta 2 contact sites, were subject to a high degree of conservation, indicating the existence of functional constraints on them also in the genus Xenopus.

Amino Acid Sequence↗
PubMed1966

Antibody production by cells in tissue culture. I. Morphological evolution of lymph node and spleen cells in culture.

An organ culture technique was used to investigate the migration and the morphological evolution of lymphocytes from lymphopoietic tissues. This evolution was compared with the behavior of cells extracted from the tissue and kept in nutritive medium in vitro. It was found that cells were continuously migrating from the fragments of lymph nodes or spleen, and were attaching to the glass. They spread on glass, their protoplasm enlarged and their nucleus became clearer. The evolution towards blastoid cells was identical with that described under artificial stimulation by PHA for example. Cytological identification of the cells actively engaged in antibody synthesis (as detected by local hemolysis in gum) at the time of staining, showed that several distinct cellular types were active, including plasma cells and macrophagelike cells. It is assumed that the stimulated lymphocytes, after spontaneous migration from the tissue are able to evolve into an "immunoblast" stage and then, eventually after fixation upon a physical support, to initiate antibody synthesis.

Antibody Formation↗
PubMed2006

Application of comparative phylogenomics to study the evolution of Yersinia enterocolitica and to identify genetic differences relating to pathogenicity.

Yersinia enterocolitica, an important cause of human gastroenteritis generally caused by the consumption of livestock, has traditionally been categorized into three groups with respect to pathogenicity, i.e., nonpathogenic (biotype 1A), low pathogenicity (biotypes 2 to 5), and highly pathogenic (biotype 1B). However, genetic differences that explain variation in pathogenesis and whether different biotypes are associated with specific nonhuman hosts are largely unknown. In this study, we applied comparative phylogenomics (whole-genome comparisons of microbes with DNA microarrays combined with Bayesian phylogenies) to investigate a diverse collection of 94 strains of Y. enterocolitica consisting of 35 human, 35 pig, 15 sheep, and 9 cattle isolates from nonpathogenic, low-pathogenicity, and highly pathogenic biotypes. Analysis confirmed three distinct statistically supported clusters composed of a nonpathogenic clade, a low-pathogenicity clade, and a highly pathogenic clade. Genetic differences revealed 125 predicted coding sequences (CDSs) present in all highly pathogenic strains but absent from the other clades. These included several previously uncharacterized CDSs that may encode novel virulence determinants including a hemolysin, a metalloprotease, and a type III secretion effector protein. Additionally, 27 CDSs were identified which were present in all 47 low-pathogenicity strains and Y. enterocolitica 8081 but absent from all nonpathogenic 1A isolates. Analysis of the core gene set for Y. enterocolitica revealed that 20.8% of the genes were shared by all of the strains, confirming this species as highly heterogeneous, adding to the case for the existence of three subspecies of Y. enterocolitica. Further analysis revealed that Y. enterocolitica does not cluster according to source (host).

Animals↗
PubMed1987

Basic studies of hydrogen evolution by Escherichia coli containing a cloned Citrobacter freundii hydrogenase gene.

Citrobacter freundii genes that complemented Escherichia coli hyd-(hydrogenase activity) mutation were cloned in plasmids pCBH4 (6.2 kb) and pCBH6(5.7 kb). Hydrogen evolution by the transformant E. coli HK-8(pCBH4 or pCBH6) was investigated. The optimum culture temperature of recombinant E. coli cells for hydrogen evolution from glucose was in the neighborhood of 18 degrees C. The recombinant E. coli cells cultured at this condition showed a several-fold increase of hydrogen evolution, as compared with that of the wild-type cells. The plasmid-retention stability of this recombinant E. coli was extremely high, especially plasmid pCBH4, which was completely retained during 2 wk without any restriction. Hydrogen production by immobilized recombinant E. coli was then investigated using cells cultured at 18 degrees C. The hydrogen evolution rate from glucose and Lennox-broth were about twofold higher than that of E. coli C600, and this high hydrogen evolution rate was maintained for more than 1 mo.

Citrobacter↗
PubMed2006

Mate choice evolution, dominance effects, and the maintenance of genetic variation.

Female mate choice influences the maintenance of genetic variation by altering the mating success of males with different genotypes. The evolution of preferences themselves, on the other hand, depends on genetic variation present in the population. Few models have tracked this feedback between a choice gene and its effects on genetic variation, in particular when genes that determine offspring viability and attractiveness have dominance effects. Here we build a population genetic model that allows comparing the evolution of various choice rules in a single framework. We first consider preferences for good genes and show that focused preferences for homozygotes evolve more easily than broad preferences, which allow heterozygous males high mating success too. This occurs despite better maintenance of genetic diversity in the latter scenario, and we discuss why empirical findings of superior mating success of heterozygous males consequently do not immediately lead to a better understanding of the lek paradox. Our results thus suggest that the mechanisms that help maintain genetic diversity also have a flipside of making female choice an inaccurate means of producing the desired kind of offspring. We then consider preferences for heterozygosity per se, and show that these evolve only under very special conditions. Choice for compatible genotypes can evolve but its selective advantage diminishes quickly due to frequency-dependent selection. Finally, we show that our model reproduces earlier results on selfing, when the female choice strategy produces assortative mating. Overall, our model indicates that various forms of heterozygote-favouring (or variable) female choice pose a problem for the theory of sexual ornamentation based on indirect benefits, rather than a solution.

Animals↗
PubMedDate not supplied

Viscosity of semiflexible chitosan solutions: influence of concentration, temperature, and role of intermolecular interactions.

The influence of polymer concentration and temperature on the rheological behavior of chitosan solution was studied. The threshold concentrations for the different viscometric regimes were determined and the different power laws exponents were calculated and compared with those predicted from models. Different observations and the high values of these exponents within the high concentration region lead to consideration of the presence of intermolecular interactions as soon as the polymer concentration is larger than the overlap concentration. The activation energy was determined as a function of the polymer concentration, and its evolution was compared with theoretical predictions. A gel-sol transition was demonstrated at high concentrations.

Carbohydrate Sequence↗
PubMed2005

[Risk factors of death in children with diarrhea and shock admitted to the intensive care unit].

BACKGROUND: Describe clinical and epidemiological characteristics of pediatric patients diagnosed with acute diarrhea and shock, admitted to the pediatric intensive care unit, in order to compare the evolution of clinical data between the survival and non-survival groups, thereby identifying the risk factors of death. METHODS: In the Pediatric Intensive Care Unit of the Clinical Hospital at the State University of Campinas (UNICAMP), a non-controlled, descriptive and retrospective study was carried out from February 1994 to January 1998 The epidemiological and clinical/evolution data were analyzed and the groups of those who survived (56) and did not survive (15) were compared. For continuous variables, the Chi-Square test was used and for categorical variables, the Fisher's Exact test, for values lower than five. RESULTS: Seventy one children aged from 0.4 to 13.9 months were admitted, 15 of them died (21.2%). Low birth weight was found in 18.1% and the mean breast-feeding time was 1.1 months. The average length of stay was 5.6 days. 52/71 children needed mechanical ventilation, use of vasoactive drugs and sodium bicarbonate was necessary in 23/71 and 15/71, respectively. 93% of children were given antibiotics. The use of sodium bicarbonate, vasoactive drugs and mechanical ventilation showed an association with risk of death, but only vasoactive drugs (OR=18.56) and an age less than 3 months (OR=0.10) showed a statistically significant difference in multivariate analysis. CONCLUSIONS: Acute diarrhea and shock occurred mainly in children under 3 months of age with a severe clinical/laboratorial condition. During clinical evolution, the high risk of death was related to the use of vasoactive drugs, a support therapy used in critical patients.

Acute Disease↗