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At least 703 records · Page 39Linked to original sources
PubMed2004

The evolution of recovery from desiccation stress in laboratory-selected populations of Drosophila melanogaster.

We examined the capacity for physiological recovery from the effects of desiccation in five replicate populations of Drosophila melanogaster that have been selected for enhanced desiccation resistance (D populations) and in five replicate control populations (C populations). The capacity to recover was signified by the ability to restore three somatic components, namely whole-body water, dry mass and sodium content, all of which are reduced during desiccation. Throughout a period of recovery following a bout of desiccation, the flies were offered one of three fluids: distilled water, saline solution, or saline+sucrose solution. Our findings indicate that, when allowed to recover on saline+sucrose solution, D populations have the capacity to restore water at a greater rate than C populations and are able to fully restore dry mass and sodium content to the levels observed in non-desiccated, hydrated D flies. When provided with this same solution during recovery, C flies are unable to restore dry mass and are faced with an elevated sodium load. Desiccation resistance of the flies subsequent to recovery was also examined. We provide evidence that the greatest desiccation resistance in the D populations is associated with the restoration of all three somatic components, suggesting that not only water content, but also dry mass and sodium, may contribute to the enhanced desiccation resistance that has evolved in these populations.

Adaptation, Physiological↗
PubMed1990

Evolution of lipoprotein receptors. The chicken oocyte receptor for very low density lipoprotein and vitellogenin binds the mammalian ligand apolipoprotein E.

The laying hen expresses two different lipoprotein transport receptors in cell-specific fashion. On the one hand, a 95-kDa oocyte membrane protein mediates the uptake of the major yolk precursors, very low density lipoprotein, and vitellogenin; on the other hand, somatic cells synthesize a 130-kDa receptor that is involved in the regulation of cellular cholesterol homeostasis (Hayashi, K., Nimpf, J., and Schneider, W. J. (1989) J. Biol. Chem. 264, 3131-3139). Here we show that the oocyte-specific receptor binds, in addition to the yolk precursor proteins, an apolipoprotein of mammalian origin, apolipoprotein E. Ligand blotting, a solid-phase binding assay, and antireceptor antibodies were employed to demonstrate that binding of vitellogenin, very low density lipoprotein (via apolipoprotein B), and apolipoprotein E occurs to closely related, if not identical, sites on the 95-kDa oocyte receptor. The binding properties of lipovitellin, which harbors the receptor recognition site of vitellogenin, are analogous to those of apolipoprotein E: both require association with lipid for expression of functional receptor binding. The ligand specificity of the avian oocyte lipoprotein receptor supports the hypothesis that vitellogenin, which has evolved in oviparous species, represents a counterpart to mammalian apolipoprotein E.

Animals↗
PubMed2005

Sexual selection, genetic conflict, selfish genes, and the atypical patterns of gene expression in spermatogenic cells.

This review proposes that the peculiar patterns of gene expression in spermatogenic cells are the consequence of powerful evolutionary forces known as sexual selection. Sexual selection is generally characterized by intense competition of males for females, an enormous variety of the strategies to maximize male reproductive success, exaggerated male traits at all levels of biological organization, co-evolution of sexual traits in males and females, and conflict between the sexual advantage of the male trait and the reproductive fitness of females and the individual fitness of both sexes. In addition, spermatogenesis is afflicted by selfish genes that promote their transmission to progeny while causing deleterious effects. Sexual selection, selfish genes, and genetic conflict provide compelling explanations for many atypical features of gene expression in spermatogenic cells including the gross overexpression of certain mRNAs, transcripts encoding truncated proteins that cannot carry out basic functions of the proteins encoded by the same genes in somatic cells, the large number of gene families containing paralogous genes encoding spermatogenic cell-specific isoforms, the large number of testis-cancer-associated genes that are expressed only in spermatogenic cells and malignant cells, and the overbearing role of Sertoli cells in regulating the number and quality of spermatozoa.

Animals↗
PubMed1995

Forced evolution of glutathione S-transferase to create a more efficient drug detoxication enzyme.

Glutathione S-transferases (EC 2.5.1.18) in mammalian cells catalyze the conjugation, and thus, the detoxication of a structurally diverse group of electrophilic environmental carcinogens and alkylating drugs, including the antineoplastic nitrogen mustards. We proposed that structural alteration of the nonspecific electrophile-binding site would produce mutant enzymes with increased efficiency for detoxication of a single drug and that these mutants could serve as useful somatic transgenes to protect healthy human cells against single alkylating agents used in cancer chemotherapy protocols. Random mutagenesis of three regions (residues 9-14, 102-112, and 210-220), which together compose the glutathione S-transferase electrophile-binding site, followed by selection of Escherichia coli expressing the enzyme library with the nitrogen mustard mechlorethamine (20-500 microM), yielded mutant enzymes that showed significant improvement in catalytic efficiency for mechlorethamine conjugation (up to 15-fold increase in kcat and up to 6-fold increase in kcat/Km) and that confer up to 31-fold resistance, which is 9-fold greater drug resistance than that conferred by the wild-type enzyme. The results suggest a general strategy for modification of drug- and carcinogen-metabolizing enzymes to achieve desired resistance in both prokaryotic and eukaryotic plant and animal cells.

Amino Acid Sequence↗
PubMed2000

Grandmother hypothesis and primate life histories.

The adaptive significance of midlife menopause in human females has long engaged the attention of evolutionary anthropologists. In spite of extensive debate, the problem has only recently been examined in the context of primate life histories. Here I extend those investigations by comparing life history traits in 16 primate species to test predictions generated from life history theory. In humans, late ages of maturity and higher than expected birth rates are systematically associated with extended postmenopausal longevity. Links among these adjustments on the primate pattern can explain how selection could slow somatic senescence without favoring extension of the fertile span. This conclusion is consistent with the observation that our fertile spans are similar to those of other pongids. The shape of the argument herein demonstrates the utility of life history theory for solving problems of adaptive evolution in female life history traits, with consequences for broader arguments regarding human evolution.

Aging↗
PubMed1986

Neocortical layers I and II of the hedgehog (Erinaceus europaeus). I. Intrinsic organization.

The intrinsic organization and interlaminar connections in neocortical layers I and II have been studied in adult hedgehogs (Erinaceus europaeus) using the Golgi method. Layer I contains a dense plexus of horizontal fibers, the terminal dendritic bouquets of pyramidal cells of layer II and of underlying layers, and varieties of intrinsic neurons. Four main types of cells were found in layer I. Small horizontal cells represent most probably persisting foetal horizontal cells described for other mammals. Large horizontal cells, tufted cells, and spinous horizontal cells were also found in this layer. Layer II contains primitive pyramidal cells representing the most outstanding feature of the neocortex of the hedgehog. Most pyramidal cells in layer II have two, three or more apical dendrites, richly covered by spines predominating over the basal dendrites. These cells resemble pyramidal cells found in the piriform cortex, hippocampus and other olfactory areas. It is suggested that the presence of these neurons reflects the retention of a primitive character in neocortical evolution. Cells with intrinsic axons were found among pyramidal cells in layer II. These have smooth dendrites penetrating layer I and local axons forming extremely complex terminal arborizations around the bodies and proximal dendritic portions of pyramidal cells. They most probably effect numerous axo-somatic contacts resembling basket cells. The similarity of some axonal terminals with the chandelier type of axonal arborization is discussed. Other varieties of cells located in deep cortical layers and having ascending axons for layers I and II were also studied. It is concluded that the two first neocortical layers represent a level of important integration in this primitive mammal.

Animals↗
PubMed1993

The dichotomy between germ line and somatic line, and the origin of cell mortality.

The germ cells of extant animals are potentially immortal, whereas somatic cells are mortal, that is, they are able to carry out only a finite number of divisions. In this article we propose an evolutionary interpretation of these differences. We assume that germ cells of the earliest metazoans inherited immortality from their unicellular ancestor, while somatic cells acquired mortality by gaining new functions. It follows that cell mortality was under genetic control from the beginning of metazoan life.

Animals↗
PubMed1982

The nucleotide sequence of phenylalanine tRNA of Xenopus laevis.

The nucleotide sequence of Xenopus laevis phenylalanine tRNA extracted from oocytes was determined to be: pGCCGAAAUAm2GCUCm1AG DDGGGAGAGCm22 G psi psi AGACmUGmAAYA psi C UAAAGm7GDCm5CCUGGT psi CGm1AUCCCGG GUUUCGGCACCAoH. This result was achieved by analysing, with classical procedures [6], the oligonucleotides obtained after digestion by T1 or pancreatic ribonuclease. This sequence is identical to the mammalian sequence. It has been entirely conserved during 10(8) years, the time lapse between the divergence of amphibians and mammals in evolution. In contrast to 5S RNA, no important heterogeneity has been found in the oocyte sequence, suggesting that there is only a single sequence for tRNAphe in X. laevis. Small differences are seen in the elution pattern from RPC-5 columns for immature oocyte and somatic tRNAphe. They are probably due to a submodification of methyl-5-cytidine residues, which appear to be about half methylated in tRNAphe as well as in total tRNA from immature oocytes.

Animals↗
PubMed2003

Immunity through DNA deamination.

Functional antibody genes assembled by V(D)J joining are subsequently diversified by somatic hypermutation, gene conversion and class-switch recombination. Recent evidence indicates that all three processes are caused by the deamination of cytosine to uracil at sites within the immunoglobulin (Ig) loci, with the pattern of diversification depending on the pathway used for resolving the initiating dU-dG lesion. Whereas DNA deamination targeted to the endogenous Ig locus triggers a program of somatic gene diversification that underpins adaptive immunity, deamination targeted to foreign DNA might have arisen initially as a form of innate immunity. Furthermore, the observation that members of the DNA deaminase family can target inappropriate genes suggests they might also contribute to mutations during genome evolution, as well as in cancer.

Animals↗
PubMedDate not supplied

[A statistical analysis of the variation in the cephalometric measures of acromegaly patients].

Acromegaly represents the endocrine disease which includes the somatic and metabolic disorders secondly resulting to the augmentation of the Growth Hormone secretion after the growth cartilages closing (in adult). In this study we want to describe the craniofacial cephalometric qualitative and quantitative disorders and to emphasize their implications in the onset and the evolution of the stomatognathic system dysfunctional syndrome. For proving this things, we made a statistical study using a statistics function named "standard deviation" which is a measure of how widely values are dispersed from the average value.

Acromegaly↗
PubMedDate not supplied

[Optimal age of sexual maturity and limitations of juvenile survival in mammals].

Although the life history evolution of small- and large-bodied mammals seems to be governed by different factors, the both shows relative neonate size and juvenile survival to be slightly dependent on body mass. I propose a hypothesis that natural selection simultaneously maximizes a time to maturity (minimizes somatic growth rate) and a number of newborn survived to reproduction. In this case optimal juvenile survival of large-bodied mammals must be close to e-beta and that of small-bodied approximately e-(1 + beta), where beta is the slope of the regression of log annual fecundity on log annual juvenile mortality. Analysis of vital characters for 71 mammal species revealed the slope to be close to unity. As a result frequency distribution of log juvenile survival shows bimodality which coincides well with predicted optimal survival for large- and small-bodies species. It is shown that the relative neonate size can be directly proportional to the juvenile survival and inversely proportional to the lifetime offspring production irrespective of mortality factors.

Animals↗
PubMed2001

[Evolutionary regularities of somatic polyploidy in salivary glands of the Gastropod molluscs. II. Subclass Pectinibranchia: order Anisorbranchia].

Salivary glands of 5 species of gastropod molluscs of the order Anisobranchia, the most ancient order within the subclass Pectinibranchia, have been investigated by histological and cytochemical methods, including DNA cytophotometry. Glandular cells of the following types were recognized: granular cells (with glycoproteid granular inclusions), mucocytes-I (including sulfatic acid mucopolysaccharides), mucocytes-II (including neutral and acid polysaccharides and proteins), and epithelial ciliated cells. All the described cell types are considered to be independent and their morphofunctional characteristics coincide with those of salivary gland cells of the gastropod molluscs of subclasses Cyclobranchia and Scutibranchia. It has been shown that somatic polyploidy in salivary glands in the Anisobranchia molluscs, likely as in those of other Archaeogastropoda (Cyclobranchia and Scutibranchia), is actually absent.

Animals↗
PubMed2003

Prevention of the complications of diabetes.

For patients with diabetes mellitus (DM), chronic complications can be devastating. Cardiovascular illness, the major cause of morbidity and mortality among these patients, encompasses macrovascular disease, with heart attacks, strokes, and gangrene; and microvascular disease, with retinopathy, nephropathy, and neuropathy (somatic and autonomic). Macrovascular events occur earlier in individuals with DM than in people without DM, and the underlying pathologies are often more diffuse and severe. Diabetic arteriopathy, which encompasses endothelial dysfunction, inflammation, hypercoagulability, changes in blood flow, and platelet abnormalities, contributes to the early evolution of these events. Efforts are under way to determine interventions that may have the potential to prevent or halt the complications of DM. Tight glucose and blood pressure (BP) control is known to improve the vascular status of patients with DM by varying degrees. Use of anti-inflammatory drugs and lowering low-density lipoprotein cholesterol (LDL-C) levels are also useful. An emerging understanding of the importance of small, dense LDL-C and the anti-inflammatory effects of statins has provided new algorithms for primary prevention of macrovascular disease. Antiplatelet agents have also been shown to be effective in the secondary prevention of cardiovascular events. In the ideal world every risk factor would be addressed and each person with DM would have excellent glycemic control, low to normal BP, and a low LDL level, and would be taking an angiotensin-converting enzyme (ACE) inhibitor, together with a statin, aspirin, and clopidogrel. Under these near-perfect conditions, the emerging epidemic of macrovascular disease could be contained. Microvascular disease, however, is a consequence of hyperglycemia. For every 1% reduction in glycosylated hemoglobin it is possible to achieve a 22% to 35% reduction in the microvascular complications. BP control is vital and the liberal use of ACE inhibitors and angiotensin receptor blockers to slow the progression of renal disease should drastically reduce the incidence of blindness, dialysis, and amputations. This article provides an overview of prevention of macrovascular disease such as stroke, myocardial infarction, and peripheral arterial disease and microvascular complications such as retinopathy, nephropathy, and neuropathy in patients with DM.

Adult↗
PubMedDate not supplied

[Anxiety and medicine: what is the role of the psychiatrist?].

The relationship between medicine and psychiatry is complex and sometimes a little difficult. Anxiety is frequently met in somatic medicine units and particularly in General Hospital where psychiatrists are often required for crisis situations. So, anxiety disorder becomes a link between physicians and psychiatrists looking after same inpatients. Epidemiological high comorbidity too is demonstrated between anxiety and somatic disorders. More and more frequently, psychiatrists are engaged for care of post traumatic stress disorders. In fact, in modern medicine, the psychiatrist is collecting medical, psychosocial and humanist points of view. His missions of clinician, teacher, and researcher seem really important for the future evolution of medicine.

Anxiety Disorders↗
PubMed1994

Self and nonself: duality of immune system.

From the viewpoint of evolution, mammalian immunity has been developed to prevent invasion by foreign bodies including parasites and microorganisms and not to survey oncogenesis. The surveillance system on oncogenesis has been lost in the evolutionary process from amphibians to mammals. The essential duality between developmental antigens and tumor specific antigens is important in explaining what the target of self-defense mechanisms is. This duality between self-defense and defense against foreign bodies originated from invertebrates as shown in insects. Immunity has been developed to survey retrodifferentiation of somatic cells and to drive the developmental process in organogenesis. Under these conditions, the clonal deletion theory of immunocyte differentiation will lose its teleological meaning. Also, the hypothesis explaining self reactivity of immunity by the immune system recognizing only an 'internal image' composed of an idio-antiidio network of immunocytes and antibodies is overly pedantic.

Animals↗
PubMed1994

Hindbrain structures involved in pain processing as revealed by the expression of c-Fos and other immediate early gene proteins.

We have used the evoked expression of the immediate early gene-encoded proteins (c-Fos, Fos B, Jun B, Jun D, c-Jun and Krox-24) to monitor sensory processing in the hindbrain structures of rats undergoing somatic inflammation. Experiments were performed on freely moving animals that did not experience constraints other than those imposed by the disease itself. Local injections of chemicals were used to cause subcutaneous inflammation of the plantar foot or monoarthritis by intracapsular injection. Labelling was studied at survival times that corresponded either to the time points of maximum labelling in the spinal cord (4 h for the subcutaneous model, 24 h and two weeks for the monoarthritis model) or at survival times that corresponded to the chronic phase of monoarthritis evolution (six, nine and 15 weeks). Controls consisted of freely moving, unstimulated animals. Basal expression was observed for all immediate early genes and in a variety of structures, but always remained moderate. All immediate early gene-encoded protein expressions except c-Jun were evoked, but except for c-Fos, and to a lesser extent Jun D, intensities of staining always remained faint. The following results will be mainly based on c-Fos expression, as this protein proved to be the most effective marker for all the survival times studied. Somatic pain evoked c-Fos expression in a subset of discrete subregions of both the caudal medulla oblongata and transitional areas of the pontomesencephalic junction. In the caudal medulla oblongata, structures involved were the caudal intermediate reticular nucleus, the subnucleus reticularis dorsalis, the ventrolateral reticular formation and the lateral paragigantocellular nucleus. Structures involved at the pontomesencephalic junction level mostly included the superior and dorsal lateral subnuclei of the parabrachial area, the nucleus cuneiformis and the most caudal portions of the lateral central gray, also including the laterodorsal tegmental nucleus; labelling in other lateral subnuclei of the parabrachial area always remained moderate. Staining in the caudal reticular areas was evident only at short survival times (4 and 24 h survival times in subcutaneous and monoarthritis models, respectively). Staining in nuclei of the pontomesencephalic junction was evident in all cases except for the very long survival periods (six to 15 weeks) of monoarthritis. In all cases staining was bilateral with contralateral predominance with regard to the stimulated limb. The present work demonstrates that hindbrain structures involved in somatic pain processing can be effectively identified in behaving animals and that c-Fos is the most reliable activity marker in this case.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2006

Chromosome evolution in the Laurales based on analyses of original and published data.

We present a summary of currently available chromosome information for all seven families in the order Laurales on the basis of original and previously published data and discuss the evolution of chromosomes in this order. Based on a total of 53 genera for which chromosome data were available, basic chromosome numbers appear consistent within families: x = 11 (Calycanthaceae); x = 22 (Atherospermataceae and Siparunaceae); x = 19 (Monimiaceae); and x = 12 and 15 (Lauraceae). The Hernandiaceae have diverse numbers: x = 15 (Gyrocarpoideae) and x = 18 and 20 (Hernandioideae). Karyotype analyses showed that Hennecartia, Kibaropsis, and Matthaea (all Monimiaceae) contained two or three sets of four distinct chromosomes in 38 somatic chromosomes, suggesting that 2n = 38 was derived by aneuploid reduction from 2n = 40, a tetraploid of x = 10. In light of the overall framework of phylogenetic relationships in the Laurales, we show that x = 11 is an archaic base number in the order and is retained in the Calycanthaceae, which are sister to the remainder of the order. Polyploidization appears to have occurred from x = 11 to x = 22 in a common clade of the Siparunaceae, Atherospermataceae, and Gomortegaceae (although 2n = 42 in the Gomortegaceae), and aneuploid reduction from x = 11 to x = 10 occurred in a common clade of the Hernandiaceae, Lauraceae, and Monimiaceae. To understand chromosome evolution in the Lauraceae, however, more studies are needed of genera and species of Cryptocaryeae.

Aneuploidy↗
PubMed2026

Paired Whole-Genome Sequencing of Scalp Angiosarcoma and Matched Lung Metastasis Reveals Common Clonal Origin and Lung-Specific Evolution.

Background and Clinical Significance: Cutaneous angiosarcoma frequently metastasizes to the lungs, where it may rarely present as diffuse cystic lung disease with recurrent pneumothorax, resulting in substantial diagnostic difficulty. We report a case of pulmonary metastatic cutaneous angiosarcoma in which paired whole-genome sequencing (WGS) of the primary and metastatic lesions was performed to clarify clonal origin and characterize metastatic evolution. Case Presentation: A 65-year-old man with recurrent right-sided pneumothorax and progressive bilateral cystic lung lesions underwent skin and lung biopsies. Histopathological examination and immunohistochemistry established the diagnosis of cutaneous angiosarcoma with pulmonary metastases. Paired WGS was performed on matched scalp and lung tumor specimens to evaluate shared and lesion-specific genomic alterations, pathway enrichment, and copy-number changes. Histopathology confirmed metastatic angiosarcoma involving the lungs. WGS identified 128 shared somatic alterations, supporting a common clonal origin, together with lung-specific and skin-specific mutations indicative of continued genomic divergence. Recurrent alterations involving POT1 and FLT4 were preserved in both lesions, whereas additional POT1 and TP53 alterations were detected only in the pulmonary metastasis. Pathway analysis demonstrated preferential enrichment of IGF1-mTOR, RAS, and WNT/LRP6 signaling in the metastatic lesion, while Gene Ontology analysis suggested functional divergence associated with metastatic progression. Conclusions: Pulmonary metastatic angiosarcoma should be considered in patients presenting with unexplained diffuse cystic lung disease and recurrent pneumothorax, particularly when pathological findings are inconclusive. Paired WGS complemented conventional histopathology by confirming the metastatic origin and providing insights into clonal evolution and lesion-specific molecular alterations, highlighting its potential value in the investigation of rare metastatic malignancies.

angiosarcoma↗