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PubMed2002

Comparative phylogenetic analysis of the evolution of semelparity and life history in salmonid fishes.

The selective pressures involved in the evolution of semelparity and its associated life-history traits are largely unknown. We used species-level analyses, independent contrasts, and reconstruction of ancestral states to study the evolution of body length, fecundity, egg weight, gonadosomatic index, and parity (semelparity vs. degree of iteroparity) in females of 12 species of salmonid fishes. According to both species-level analysis and independent contrasts analysis, body length was positively correlated with fecundity, egg weight, and gonadosomatic index, and semelparous species exhibited a significantly steeper slope for the regression of egg weight on body length than did iteroparous species. Percent repeat breeding (degree of iteroparity) was negatively correlated with gonadosomatic index using independent contrasts analysis. Semelparous species had significantly larger eggs by species-level analysis, and the egg weight contrast for the branch on which semelparity was inferred to have originated was significantly larger than the other egg weight contrasts, corresponding to a remarkable increase in egg weight. Reconstruction of ancestral states showed that egg weight and body length apparently increased with the origin of semelparity, but fecundity and gonadosomatic index remained more or less constant or decreased. Thus, the strong evolutionary linkages between body size, fecundity, and gonadosomatic index were broken during the transition from iteroparity to semelparity. These findings suggest that long-distance migrations, which increase adult mortality between breeding episodes, may have been necessary for the origin of semelparity in Pacific salmon, but that increased egg weight, leading to increased juvenile survivorship, was crucial in driving the transition. Our analyses support the life-history hypotheses that a lower degree of repeat breeding is linked to higher reproductive investment per breeding episode, and that semelparity evolves under a combination of relatively high juvenile survivorship and relatively low adult survivorship.

Animals↗

PubMed1984

Study of the evolution of acute phase reactants and of thromboxane and prostacyclin during calcium pyrophosphate-induced pleurisy in the rat.

By using a clearly defined model of acute inflammation in rats, CaPP-induced pleurisy, we compared the evolution of four APR levels (Hp, HpX, alpha 2M, SAP) at a local and peripheral site. At the same time we studied thromboxane and prostacyclin concentrations in pleural exudate. The levels of APR have shown a progressive increase up to 24 h. For alpha 2M, Hp, HpX the increase in serum concentration was more rapid than in exudate, whereas the evolution of SAP level was parallel in the intra and extra-vascular compartments. On the other hand the levels of albumin and transferrin which are not APR remained constant in serum and also in exudate from 6 h to 24 h. Thromboxane and prostacyclin levels reached a peak during the first two hours of the inflammatory reaction followed by a rapid decreased. These prostanoids may be considered as early and transient mediators of acute inflammation, whereas the acute phase proteins studied have a more prolonged role in the inflammatory reaction.

Acute-Phase Proteins↗

PubMedDate not supplied

[Organs of hearing and equilibrium during ontogenesis of mammals].

The peripheral part of acoustic analyzer was studied during pre- and postnatal development of mammals. The main trends of structural evolution of the outer, middle, and inner ear were followed in representatives of different ecological groups during postnatal development. The use of ecologomorphological approach made it possible to establish that specific structural features of the hearing organ in different mammals are determined by adaptation to specific acoustic properties of the environment. It was shown that morphofunctional adaptations directed at optimization of acoustic sensitivity in different environmental conditions were leading in the hearing organ evolution. Comparative-embryological studies of the peripheral part of acoustic system made it possible to determine the stages of formation of individual structures and establish general patterns of prenatal development of the organs of hearing and equilibrium in different mammals.

Animals↗

PubMed2000

Current awareness on comparative and functional genomics [bibliography].

In order to keep subscribers up-to-date with the latest developments in their field, this current awareness service is provided by John Wiley & Sons and contains newly-published material on comparative and functional genomics. Each bibliography is divided into 16 sections. 1 Reviews & symposia; 2 General; 3 Large-scale sequencing and mapping; 4 Genome evolution; 5 Comparative genomics; 6 Gene families and regulons; 7 Pharmacogenomics; 8 Large-scale mutagenesis programmes; 9 Functional complementation; 10 Transcriptomics; 11 Proteomics; 12 Protein structural genomics; 13 Metabolomics; 14 Genomic approaches to development; 15 Technological advances; 16 Bioinformatics. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted

Animals↗

PubMed2000

Current awareness.

Animals↗

PubMed1999

Anti-HIV-1/2 Antibody Detection by Dot-ELISA in Oral Fluid of HIV Positive/AIDS Patients and Voluntary Blood Donors.

Serology is the primary means for identifying patients with HIV infection and Acquired Immunodeficiency Syndrome (AIDS). Testing of serum by serologic methods has been extensively used since 1985, not only for clinical diagnosis but also for epidemiological surveillance and donor screening in blood banks. Fast serological diagnostic techniques are now being developed, using urine and oral fluid, as an alternative for anti-HIV antibody screening, and many parallel studies are proving its accuracy. The purpose of this study was to evaluate the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of the ImmunoComb II HIV 1&2 Saliva((R)) test from Orgenics (Dot-ELISA) compared to the routine exams (ELISA and Western Blot) of HIV positive/AIDS patients, undergoing antiretroviral treatment or not, in different stages of the disease's evolution, and compared to serologic testing of known HIV negative patients by the use of serum ELISA (blood donors). To accomplish this, patients of the Immunogenic Deficiencies Control Center (CCDI) and voluntary blood donors of the Blood Bank Center of the Medical School of S&atilde:o Paulo/Federal University of São Paulo (EPM-UN I FESP) were evaluated. Sensitivity of Dot-ELISA in oral fluid was 100%, specificity 97.08%, PPV 96.66% and NPV 100%. The method used in this case study was shown to be highly sensitive and specific, being useful particularly in epidemiological surveillance and screening.

Journal Article↗

PubMed1996

Evolution of photochemically induced focal cerebral ischemia in the rat. Magnetic resonance imaging and histology.

BACKGROUND AND PURPOSE: Magnetic resonance imaging (MRI) is increasingly used to study the pathophysiological evolution of cerebral ischemia in humans and animals. We have investigated photochemically induced (rose bengal) focal cerebral ischemia, a relatively noninvasive, reproducible model for stroke, and compared the evolution of the ischemic response in vivo and postmortem with MRI and histology, respectively. METHODS: MR images weighted for T2, diffusion, and T2* and parallel histological sections stained with cresyl fast violet (CFV) and for glial fibrillary acid protein were obtained from 34 adult male Hooded Lister rats at seven time points (3.75 to 196 hours) after bilateral ischemia induction. From CFV histology, lesion volumes and cell counts were calculated; from diffusion-weighted and T2-weighted images, apparent diffusion coefficients and lesion volumes were determined. RESULTS: Both MRI and histology revealed a well-defined lesion at 3.75 hours after irradiation and a consistent pattern of temporal evolution; lesion apparent diffusion coefficients decreased significantly by 3.75 hours, increased significantly by day 2, and correlated strikingly with the decline in lesion CFV-positive cell numbers. After day 2, astrocytes and connective tissue cells invaded the infarct. Throughout the time course, lesion volumes determined in vivo and postmortem (after shrinkage correction) agreed well. CONCLUSIONS: MRI changes quantitatively reflect histopathology, revealing reproducible primary and secondary damage characteristics noninvasively. These changes essentially replicate those reported for other animal stroke models and clinically, emphasizing the value both of MRI and the photochemically induced focal cerebral ischemia model in stroke research.

Animals↗

PubMed1997

Comparative primate energetics and hominid evolution.

There is currently great interest in developing ecological models for investigating human evolution. Yet little attention has been given to energetics, one of the cornerstones of modern ecosystem ecology. This paper examines the ecological correlates of variation in metabolic requirements among extant primate species, and uses this information to draw inferences about the changes in energy demands over the course of human evolution. Data on body size, resting metabolism, and activity budgets for selected anthropoid species and human hunter-gatherers are used to estimate total energy expenditure (TEE). Analyses indicate that relative energy expenditure levels and day ranges are positively correlated with diet quality; that is, more active species tend to consume more energy-rich diets. Human foragers fall at the positive extremes for modern primates in having high expenditure levels, large ranges, and very high quality diets. During hominid evolution, it appears that TEE increased substantially with the emergence of Homo erectus. This increase is partly attributable to larger body size as well as likely increases in day range and activity level. Assuming similar activity budgets for all early hominid species, estimated TEE for H. erectus is 40-45% greater than for the australopithecines. If, however, it is assumed that the evolution of early Homo was also associated with a shift to a more "human-like" foraging strategy, estimated expenditure levels for H. erectus are 80-85% greater than in the australopithecines. Changing patterns of resource distribution associated with the expansion of African savannas between 2.5 and 1.5 mya may been the impetus for a shift in foraging behavior among early members of the genus Homo. Such ecological changes likely would have made animal foods a more attractive resource. Moreover, greater use of animal foods and the resulting higher quality diet would have been important for supporting the larger day ranges and greater energy requirements that appear to have been associated with the evolution of a human-like hunting and gathering strategy.

Animals↗

PubMed1998

The natural history of hereditary chronic pancreatitis: a study of 12 cases compared to chronic alcoholic pancreatitis.

The aim of this study was to document the natural history of chronic hereditary pancreatitis and to compare its evolution to that of chronic alcoholic pancreatitis. Twelve subjects with chronic hereditary pancreatitis were followed up for a mean duration of 15.8 years (range, 1-23) and compared to subjects with chronic alcoholic pancreatitis who were followed up from 1972 to 1980. The subjects with chronic hereditary pancreatitis, when compared to those with chronic alcoholic pancreatitis, were found to have an earlier onset of symptoms (10.5 vs. 46.0 years, p < 0.05); a significant delay in diagnosis (14.3 vs. 3 years); a similar prevalence of pancreatic calcification (58 vs. 57%); a similar amount of pancreatic insufficiency; both endocrine (50 vs. 70%) and exocrine 42 vs. 38%); and a higher prevalence of pseudocysts (33 vs. 10%, p < 0.05). Only one pancreatic adenocarcinoma was diagnosed in a patient with chronic alcoholic pancreatitis. Apart from the earlier onset and the delay in diagnosis, chronic hereditary pancreatitis has a natural history similar to that of chronic alcoholic pancreatitis. The disease is progressive with a high incidence of complications, but all subjects were alive after follow-up.

Adolescent↗

PubMed2003

Epidemiology, genetic diversity, and evolution of endemic feline immunodeficiency virus in a population of wild cougars.

Within the large body of research on retroviruses, the distribution and evolution of endemic retroviruses in natural host populations have so far received little attention. In this study, the epidemiology, genetic diversity, and molecular evolution of feline immunodeficiency virus specific to cougars (FIVpco) was examined using blood samples collected over several years from a free-ranging cougar population in the western United States. The virus prevalence was 58% in this population (n = 52) and increased significantly with host age. Based on phylogenetic analysis of fragments of envelope (env) and polymerase (pol) genes, two genetically distinct lineages of FIVpco were found to cooccur in the population but not in the same individuals. Within each of the virus lineages, geographically nearby isolates formed monophyletic clusters of closely related viruses. Sequence diversity for env within a host rarely exceeded 1%, and the evolution of this gene was dominated by purifying selection. For both pol and env, our data indicate mean rates of molecular evolution of 1 to 3% per 10 years. These results support the premise that FIVpco is well adapted to its cougar host and provide a basis for comparing lentivirus evolution in endemic and epidemic infections in natural hosts.

Animals↗

PubMed1994

[Cesarean section. Hysterorrhaphy in one plane].

Morbimortality between hysterorraphy in one and two planes, was compared. One hundred patients in whom hysterorraphy in one plane, was done with a control group of one hundred with hysterorraphy in two planes, were studied, and evolution was compared. The time of surgery was 50% lees with the hysterorraphy in one plane. (P minor 0.0001). Bleeding of 100 cc. lees (P minor 0.001). There was no difference about complications of both methods. There was no difference in morbimortality. The cicatrization during sixty days after surgery is the same.

Blood Loss, Surgical↗

PubMed2002

The evolution of cuckoo parasitism: a comparative analysis.

Cuckoos (family Cuculidae) show the highest diversity of breeding strategies within one bird family (parental care, facultative and obligate brood parasites). We used independent contrasts from two phylogenies to examine how this variation was related to 13 ecological and life-history variables. The ancestral state was probably tropical, resident, forest cuckoos with parental care. The evolution of brood parasitism was correlated with a shift to more open habitats, a change in diet, increases in species breeding-range size and migration, and a decrease in egg size. Once parasitism had evolved, more elaborate parasitic strategies (more harmful to host fitness) were correlated with decreased egg size, a change in diet, increased breeding-range size and migration, a shortened breeding season and a decrease in local abundance. Establishing the most probable evolutionary pathways, using the method of Pagel, shows that changes in ecological variables (such as migration, range size and diet type) preceded the evolution of brood parasitism, which is likely to be a later adaptation to reduce the cost of reproduction. By contrast, brood parasitism evolved before changes in egg size occurred, indicating that egg size is an adaptive trait in host--parasite coevolution. Our results suggest that the evolution of cuckoo brood parasitism reflects selection from both ecological pressures and host defences.

Adaptation, Physiological↗

PubMed1984

Molecular evolution of chloroplast DNA sequences.

Comparative data on the evolution of chloroplast genes are reviewed. The chloroplast genome has maintained a similar structural organization over most plant taxa so far examined. Comparisons of nucleotide sequence divergence among chloroplast genes reveals marked similarity across the plant kingdom and beyond to the cyanobacteria (blue-green algae). Estimates of rates of nucleotide substitution indicate a synonymous rate of 1.1 x 10(-9) substitutions per site per year. Noncoding regions also appear to be constrained in their evolution, although addition/deletion events are common. There have also been evolutionary changes in the distribution of introns in chloroplast encoded genes. Relative to mammalian mitochondrial DNA, the chloroplast genome evolves at a conservative rate.

Biological Evolution↗

PubMed2006

Dynamic evolution at pericentromeres.

Pericentromeres are exceptional genomic regions: in animals they contain extensive segmental duplications implicated in gene creation, and in plants they sustain rearrangements and insertions uncommon in euchromatin. To examine the mechanisms and patterns of plant pericentromere evolution, we compared pericentromere sequence from four Brassicaceae species separated by <15 million years (Myr). This flowering plant family is ideal for studying relationships between genome reorganization and pericentromere evolution-its members have undergone recent polyploidization and hybridization, with close relatives changing in genome size and chromosome number. Through sequence and hybridization analyses, we examined regions from Arabidopsis arenosa, Capsella rubella, and Olimarabidopsis pumila that are homologous to Arabidopsis thaliana pericentromeres (peri-CENs) III and V, and used FISH to demonstrate they have been maintained near centromere satellite arrays in each species. Sequence analysis revealed a set of highly conserved genes, yet we discovered substantial differences in intergenic length and species-specific changes in sequence content and gene density. We discovered that A. thaliana has undergone recent, significant expansions within its pericentromeres, in some cases measuring hundreds of kilobases; these findings are in marked contrast to euchromatic segments in these species that exhibit only minor length changes. While plant pericentromeres do contain some duplications, we did not find evidence of extensive segmental duplications, as has been documented in primates. Our data support a model in which plant pericentromeres may experience selective pressures distinct from euchromatin, tolerating rapid, dynamic changes in structure and sequence content, including large insertions of mobile elements, 5S rDNA arrays and pseudogenes.

Arabidopsis↗

PubMed1991

Parallel evolution in mammalian and avian brains: comparative cytoarchitectonic and cytochemical analysis.

Comparative morphology, which is based on the selection theory of evolution, analyses the impact of function upon structure and, therefore, emphasizes the adaptive events and biological advantage during the evolution of organs. A comparison based on analogies is described here as an adequate method. The hypothesis is proposed that the evolution of the brain follows the same trends in birds as in mammals. This hypothesis is proved by (1) allometric studies of brain weight and brain structure volume in relation to body weight in mammals and birds; (2) architectonic studies using image analysis on cell and fibre stains as well as on histochemical preparations and receptor autoradiography; and (3) hodological studies with injections of [3H]leucin, HRP and WGA-HRP. The results reveal a vast amount of structural and functional similarities in avian and mammalian brain organization, especially an expansion of structures that permit multimodal integration capacity in the telencephalon. Thus, a parallel evolution occurred in these two groups of vertebrates. It is argued that this may be a general phenomenon in evolution. A cladistic approach, which is based on the concept of homologies (plesio-, apomorphies), pushes aside the existence of analogies. For this reason, cladism does not seem to be a method to answer questions of evolutionary morphology adequately.

Animals↗

PubMed2004

Evolution of nociception in vertebrates: comparative analysis of lower vertebrates.

Nociception is an important sensory system of major fundamental and clinical relevance. The nociceptive system of higher vertebrates is well studied with a wealth of information about nociceptor properties, involvement of the central nervous system and the in vivo responses to a noxious experience are already characterised. However, relatively little is known about nociception in lower vertebrates and this review brings together a variety of studies to understand how this information can inform the evolution of nociception in vertebrates. It has been demonstrated that teleost fish possess nociceptors innervated by the trigeminal nerve and that these are physiologically similar to those found in higher vertebrates. Opioid receptors and endogenous opioids are found in the brain and spinal cord of the fishes and morphine blocks avoidance learning using electric shock as well as reducing nociceptive behavioural and physiological responses to noxious stimulation. Comparative analysis of the fishes and higher vertebrates show that fish possess less C fibres than higher vertebrates. The electrophysiological properties of fish nociceptors are almost identical to those found in higher vertebrates suggesting the evolution of these properties occurred before the emergence of the fish groups.

Afferent Pathways↗

PubMed1985

Cell body responses to axonal injury: traumatic axotomy versus toxic neuropathy.

To compare the evolution of cell body responses to two different types of axonal injuries--sciatic nerve crush (axotomy) and chronic 2,5-hexanedione-induced neuropathy--we studied rat lumbar dorsal root ganglion neurons with light microscopy and morphometry. Compared with control neurons, axotomized cells showed early (1 day) increases in the frequencies of two responses, nuclear eccentricity and Nissl body displacement, and later (4 day) increases in average satellite cell nuclei and decreases in perikaryal diameters. In toxin-induced axonal degeneration, there were similar patterns of defined alterations, although the evolution progressed over weeks and the response magnitudes were smaller. We conclude that the two experimental conditions show basic morphologic similarities, implying cell body reorganization in toxic axonopathy may be a response to axonal dysfunction or degeneration.

Animals↗

PubMed2005

Application of accelerated molecular dynamics schemes to the production of amorphous silicon.

The evolving nature of a Stillinger-Weber modeled silicon glass is studied using two accelerated molecular dynamics scheme, specifically, hyperdynamics and self-guided algorithms due to Voter and due to Wu and Wang, respectively. We obtain an acceleration of the dynamics, a "boost," on the order of 20 without incurring any significant computational overhead. The validity of the results using accelerated methods is provided by comparison to a conventional molecular dynamics (MD) algorithm simulated under constant temperature conditions for more than 100 ns. We found that performing a sensitivity analysis of the effect of the parameters lambda and t1 before applying the self-guided MD scheme was important. Values of lambda greater than 0.1 and t1 equal to 1 ps were found to give improved structural evolution as compared to a conventional MD scheme. The hyperdynamics approximation scheme was found to be effective in obtaining boosts in the range of 4-12 for a small system without changing the dynamics of the evolution. However, for a large system size such an approach introduces significant perturbations to the pertinent equations of motion.

Algorithms↗