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At least 973 records · Page 54Linked to original sources
PubMed2000

A comparative study of chromosome morphology among the nine annual species of Cicer L.

Thirty-six accessions, representing the full complement of all the nine annual Cicer L. species, viz C. arietinum, C. reticulatum, C. echinospermum, C. pinnatifidum, C. judaicum, C. bijugum, C. chorassanicum, C. yamashitae and C. cuneatum, were subjected to karyotype analysis for the first time in a single comprehensive study. The detailed karyotype of C. chorassanicum was also investigated for the first time. A 12 h cold water pretreatment and 13 min 60 degrees C 1 N HCl hydrolysis confirmed a somatic chromosome number of 2n = 16 in all the species. Within species interchromosomal size variation was observed to be quite large in C. arietinum, C. reticulatum and C. echinospermum, but not in the remaining six species. Individual chromosome size ranged from 3.77 microns in C. echinospermum to 1.32 microns in C. arietinum while the haploid genome length ranged from 20.65 microns in C. echinospermum to 14.92 microns in C. cuneatum. Ample rearrangement of chromatin among chromosomes within a species was implied to have played a role in Cicer genome evolution. The nine species were classified in two groups based on karyotypic similarity, with the first group comprising the inter-crossable species C. arietinum, C. reticulatum and C. echinospermum, while the remaining species forming the second group. The first group species are also genetically close to each other as deduced by other morphological, biochemical and DNA based studies. Circumstantial evidence has lead to the speculation that perhaps karyotypic similarity and interspecific crossability are positively related to each other.

Centromere↗
PubMed2006

Microsatellite segregation analysis and cytogenetic evidence for tetrasomic inheritance in the American yam Dioscorea trifida and a new basic chromosome number in the Dioscoreae.

Despite the economic and cultural importance of the indigenous "Amerindian" yam Dioscorea trifida, very little is known about their origin, phylogeny, diversity and genetics. Consequently, conventional breeding efforts for the selection of D. trifida genotypes resistant to potyviruses which are directly involved in the regression of this species have been seriously limited. Our objective of this paper is to contribute to the clarification of the cytogenetic status, i.e., inheritance and chromosome number. Our results provide genetic evidence supporting tetrasomic behaviour of the genome of D. trifida based on chromosomal segregation pattern analysis using eight SSRs markers in three different crosses. This is the first reliable evidence of an autopolyploid species in the genus Dioscorea. The second major result in this study is the revealing of a new base chromosome number in the botanical section Macrogynodium to which D. trifida belongs. To date, our assumptions about the ploidy level of yams are based on the observations that the basic chromosome number is 10 or 9, and D. trifida was described as octoploid. The chromosome number of D. trifida accessions was also assessed using somatic chromosomic count techniques. Flow cytometry did not show significant variation of 2C DNA content among 80 accessions indicating homogeneity of the ploidy level of the cultivated D. trifida. This suggests that autotetraploidy is well established as well as the rule for the cultivated pool of D. trifida, even if the direct diploid ancestor remains to be identified. The data presented in this paper are significant and important for the effective breeding and conservation of the species and for elucidating the phylogeny and the origins of the yam and the evolution of the genus Dioscorea.

Chromosome Segregation↗
PubMed2004

[Kangaroo mother care: bibliographical review on the current attitudes, their interests and their limits].

Initiated in 1978 by a Colombian team, then largely adapted in industrialized countries as well as in poor developed countries, the kangaroo mother care (KMC) are known to ensure for low birth weight newborn, a thermoregulation, a good physiological stability and a better relational comfort with their parents. The goal of this work is to make a bibliographical review on current concepts, interests and limits of this method. We re-examined impact of the KMC on the basal metabolism, thermoregulation, growth and evolution of these children. They are helpful in the developing countries but medical safety should not be forgotten. In these countries where there's high frequentation of the services, they are able to regulate body temperature and metabolic adaptation of the newborn. In developed countries, KMC contribute to decrease anxiety of parents and improve the relations with their child. However, it is difficult to recommend their use in current practice. Rigorous randomised studies are necessary to argue their establishment in full safety, to know the neuropsychological development and the real somatic growth on the long term of the children and to known their true economic cost.

Attitude↗
PubMed1994

A human Alu RNA-binding protein whose expression is associated with accumulation of small cytoplasmic Alu RNA.

Human Alu sequences are short interspersed DNA elements which have been greatly amplified by retrotransposition. Although initially derived from the 7SL RNA component of signal recognition particle (SRP), the Alu sequence has evolved into a dominant transposon while retaining a specific secondary structure found in 7SL RNA. We previously characterized a set of Alu sequences which are expressed as small cytoplasmic RNAs and isolated a protein that binds to these transcripts. Here we report that biochemical purification of this protein revealed it as the human homolog of the SRP 14 polypeptide which binds the Alu-homologous region of 7SL RNA. The human cDNA predicts an alanine-rich C-terminal tail translated from a trinucleotide repeat not found in the rodent homolog, which accounts for why the human protein-RNA complex migrates more slowly than its rodent counterpart in RNA mobility shift assays. The human Alu RNA-binding protein (RBP) is expressed after transfection of this cDNA into mouse cells. Expression of human RBP in rodent x human somatic cell hybrids is associated with substantial increase in endogenous small cytoplasmic Alu and scB1 transcripts but not other small RNAs. These studies provide evidence that this RBP associates with Alu transcripts in vivo and affects their metabolism and suggests a role for Alu transcripts in translation in an SRP-like manner. Analysis of hybrid lines indicated that the Alu RBP gene maps to human chromosome 15q22, which was confirmed by Southern blotting. The possibility that the primate-specific structure of this protein may have contributed to Alu evolution is considered.

Amino Acid Sequence↗
PubMed1990

Localization of the DER/flb protein in embryos: implications on the faint little ball lethal phenotype.

Antibodies were raised against the Drosophila EGF receptor homolog (DER) and used for immunohistochemical analyses of Drosophila embryos. We found that DER is localized in a wide array of embryonic tissues, displaying a dynamic pattern of expression. DER appears to be expressed in all cells at the cellular blastoderm and gastrula stages. In extended-germ-band embryos, it is found predominantly in the mesoderm and the head. Finally, in retracted-germ-band embryos, DER immunoreactivity is most pronounced at sites of somatic muscle attachments and along the ventral midline of the CNS. We have thus observed that DER is expressed in the diverse tissues which are affected in the DER faint little ball (flb) embryonic lethal phenotype. The different pattern and extent of expression in each tissue suggests that the disparate aspects of the flb phenotype may result from different mechanisms of DER function. To understand the basis for the CNS phenotype of DER/flb mutants, we have closely followed the collapse of the CNS in mutant embryos. Our observations on the evolution of the final CNS phenotype, in combination with the temporo-spatial pattern of appearance of DER in the ventral neuroepithelium, suggest that this receptor participates in the second phase of neuron-glia interactions, namely in stabilization of the ladder-like CNS scaffolding formed by outgrowth of pioneer axonal processes along the glial pre-pattern.

Animals↗
PubMed2025

Single-cell mutational burden distributions in birth-death processes.

Genetic mutations are footprints of cancer evolution and reveal critical dynamic parameters of tumour growth, which otherwise are hard to measure in vivo. The mutation accumulation in tumour cell populations has been described by various statistics, such as site frequency spectra (SFS), single-cell division distributions (DD) and mutational burden distributions (MBD). While DD and SFS have been intensively studied in phylogenetics especially after the development of whole genome sequencing technology of bulk samples, MBD has drawn attention more recently with the single-cell sequencing data. Although those statistics all arise from the same somatic evolutionary process, an integrated understanding of these distributions is missing and requires novel mathematical tools to better inform the ecological and evolutionary dynamics of tumours. Here we introduce dynamical matrices to analyse and unite the SFS, DD and MBD and derive recurrence relations for the expectations of these three distributions. While we successfully recover classic exact results in pure-birth cases for the SFS and the DD through our new framework, we derive a new expression for the MBD and approximate all three distributions when death is introduced. We demonstrate a natural link between the SFS and the single-cell MBD, and show that the MBD can be regenerated through the DD. Counter-intuitively, the single-cell MBD is mainly driven by the stochasticity arising in the DD, rather than the extra stochasticity in the number of mutations at each cell division.

Single-Cell Analysis↗
PubMed1993

Screening for psychiatric symptoms and illness behaviour in a pain clinic.

Evolution of a multidisciplinary pain clinic in a rehabilitation hospital is described. The assessment process was facilitated, particularly with respect to psychiatric and psychological evaluation, by the preliminary administration of two well established but simple self-administered questionnaire instruments, the Illness Behaviour Questionnaire (IBQ) and the Crown-Crisp Experiential Index (CCEI). The characteristics of our pain clinic population are described. They demonstrate questionnaire profiles which are typical of pain patients. Attention is drawn to the CCEI profile now shown in three studies of pain patients, predominance of the somatic anxiety (S) scale occurring in all. Correlations between the IBQ and CCEI showed, inter alia, that the S scale is a measure of somatisation in pain patients. This paper aims to describe the changes in the clinic since previously published descriptions, to note the characteristics of our patient on the questionnaire instruments and to comment on the value of these questionnaires in the assessment of psychiatric symptoms and somatisation in pain clinic patients.

Adult↗
PubMed1991

Homologs of eleven loci on human chromosome 11 assigned to two owl monkey chromosomes.

We localized 11 loci mapped to human chromosome 11 to two chromosomes, 4 and 19 of owl monkey karyotype VI (2n = 49/50), by the use of somatic cell hybrids. Furthermore, using in situ hybridization to chromosomes of two owl monkey karyotypes, the HSTF1 oncogene locus was precisely localized on homologs 19q (K-VI) and 2q (K-II). Comparative analysis of available gene-mapping data among human, mouse, and owl monkey chromosomes revealed a pattern of evolutionary change in a syntenic group on human chromosome 11. These structural changes could be explained as having derived from a pericentric inversion of human chromosome region 11cen----q13 and a translocation involving human region 11q22----qter during primate evolution.

Animals↗
PubMed2001

[The benefits of aging. I. Patience and cure: spontaneous beneficial course of certain diseases].

Some chronic diseases have a favourable course and are cured spontaneously. Allergic diseases such as eczema, hay fever and asthma have a good outcome in more than 75% of cases within 7 to 25 years, depending on the kind of allergy. Migraines have also a good evolution in children and after menopause. Many symptoms due to menstruation such as dysmenorrhea, premenstrual syndrome or anemia, disappear after menopause as well as diseases due to estrogens such as uterine leiomyoma, endometriosis and prolactinoma. The risk of epilepsy relapse after a first seizure is about 40% after 2 years. The risk is lower in children. Attention deficit disorder affects 3 to 5% of children but is present in only 30% of them in adult age. The prevalence of depression decreases in women between 30 and 60 years of age. Functional somatic syndromes such as fibromyalgia, irritable bowel syndrome or dyspepsia decrease in 2/3 of cases within 5 to 10 years if there is no history of anxio-depressive symptoms. However, prognosis is reserved when initial symptoms are severe or if they are connected to sexual abuse, domestic violence or depression. Other diseases have a spontaneous favourable course such as myopia, idiopathic infertility, polycystic ovary disease or ventricular arrhythmia. The knowledge of a good prognosis enables to avoid unnecessary treatments and to reassure many patients.

Aged↗
PubMed1993

Congenital genetic instability in colorectal carcinomas.

INTRODUCTION: Oncogenic evolution is probably based on a progressive selection of clonal subpopulations from within a single clone. This selection is supposed to be based on enhanced genetic instability in the genome. In the vast majority of patients this increased lability is supposed to be the result of acquired alterations, and once established, it may contribute to the continuing, genetic instability within the neoplastic cells. It has been postulated, that inborn chromosomal instability is not limited to a few rare syndromes. Indeed, one of the common colorectal cancer (CRC) syndromes, familial adenomatous polyposis (FAP), is supposed to be a chromosomal instability syndrome. Also the hereditary nonpolyposis colorectal cancer syndrome (Lynch Syndrome (LS)) has shown genomic instability. Knudson (1971, 1985) has shown, that the same gene can be involved in both the hereditary form of a cancer and in the sporadic form of the same cancer. Due to the existence of such hereditary chromosomal instability syndromes, inherited genetic instability may be of some importance in the evolution of sporadic colorectal cancers. METHODS: In vitro research on dermal fibroblasts is based on the theory, that all studied cells of an individual carry the same genetic material, irrespective of their in vivo expression. Increased in vitro tetraploidy (IVT+) in skin fibroblast cultures is supposed to be a germinally transmitted expression of genomic instability, with special reference to LS. At the same time the chromosomal aberrations, which occur in neoplasms, can be measured by flow cytometric DNA analysis. The DNA content, thus measured, is supposed to be an expression of somatic acquired genetic instability. Finally, since occult mandibular osteomas have been shown to be associated with FAP, we have investigated a substantial part of our patients with this phenotypical marker. AIM OF STUDY: In CRC the adenoma-carcinoma sequence is widely accepted, and the purpose of our investigation was to find a correlation, if any, between: Changes in adenoma flow cytometric DNA content and histological grade and type of adenomas. Changes in dermal fibroblast IVT+ from adenoma patients and histological grade and type of adenomas. Changes in dermal fibroblast IVT+ and flow cytometrical DNA content in adenomas and carcinomas from the same patients. Furthermore, we wanted to investigate if: The occurrence of IVT+ in skin fibroblasts among patients with CRC was different from that of IVT+ among patients without colorectal neoplasies. The occurrence of IVT+ in skin fibroblasts among patients with CRC was associated with the occurrence of occult mandibular osteomas in the same patients. The occurrence of dermal fibroblast IVT+ conveyed any prognostic significance in CRC patients. RESULTS AND CONCLUSIONS: 1) A significant correlation was found between both the occurrence of skin fibroblast IVT+ and adenoma DNA aneuploidy in relation to the degree of dysplasia and histological type of adenomas. This signifies, that inborn and acquired genetic instability is correlated to the adenoma-carcinoma sequence. IVT+ was found to be correlated to the progression of adenomas to carcinomas and not to the development of adenomas. 2) A direct correlation between IVT+ and adenoma DNA aneuploidy could not be demonstrated. However, among those patients with diploid adenomas and IVT+ 57% showed villous adenomas. Among those patients with diploid adenomas and IVT- only 14% had villous adenomas. This further substantiates the correlation of IVT+ to the adenoma-carcinoma sequence. IVT+ was highly associated with DNA aneuploidy in carcinomas, and since IVT+ was found to be significantly associated with CRC's with a DNA index > or = 1.5, it is suggested that IVT+ mainly is correlated to the early steps in tumor progression. 3) IVT+ was found in 34% of sporadic CRC, and tumor DNA aneuploidy was demonstrated in 73%...

Adenoma↗
PubMed2005

Understanding the odd science of aging.

Evolutionary considerations suggest aging is caused not by active gene programming but by evolved limitations in somatic maintenance, resulting in a build-up of damage. Ecological factors such as hazard rates and food availability influence the trade-offs between investing in growth, reproduction, and somatic survival, explaining why species evolved different life spans and why aging rate can sometimes be altered, for example, by dietary restriction. To understand the cell and molecular basis of aging is to unravel the multiplicity of mechanisms causing damage to accumulate and the complex array of systems working to keep damage at bay.

Aging↗
PubMed2002

Drosophila germline invasion by the endogenous retrovirus gypsy: involvement of the viral env gene.

The endogenous retrovirus gypsy is expressed at high levels in mutant flamenco female flies. Gypsy viral particles extracted from such flies can infect naive flamenco individuals raised in the presence of these extracts mixed into their food. This results in the integration of new proviruses into the germline genome. These proviruses can then increase their copy number by (1) expression in the flamenco female somatic cells, (2) transfer into the oocyte and (3) integration into the genome of the progeny. Surprisingly, unlike the infection observed in the feeding experiments, this strategy of endogenous proviral multiplication does not seem to involve the expression of the viral env gene.

Animals↗
PubMed1992

Synteny mapping in the bovine: genes from human chromosome 4.

Genes homologous to those located on human chromosome 4 (HSA4) were mapped in the bovine to determine regions of syntenic conservation among humans, mice, and cattle. Previous studies have shown that two homologs of genes on HSA4, PGM2 and PEPS, are located in bovine syntenic group U15 (chromosome 6). The homologous mouse genes, Pgm-1 and Pep-7, are on MMU5. Using a panel of bovine x hamster hybrid somatic cells, we have assigned homologs of 11 additional HSA4 loci to their respective bovine syntenic groups. D4S43, D4S10, QDPR, IGJ, ADH2, KIT, and IF were assigned to syntenic group U15. This syntenic arrangement is not conserved in the mouse, where D4s43, D4s10, Qdpr, and Igj are on MMU5 while Adh-2 is on MMU3. IL-2, FGB, FGG, and F11, which also reside on MMU3, were assigned to bovine syntenic group U23. These data suggest that breaks and/or fusions of ancestral chromosomes carrying these genes occurred at different places during the evolution of humans, cattle, and mice.

Animals↗
PubMed1999

A lack of cerebral lateralization in schizophrenia is within the normal variation in brain maturation but indicates late, slow maturation.

The planum temporale (PT) bias, PT leftward, PT symmetry, and PT rightward reversal and sidedness preference, consistent right-handedness, ambilaterality, and consistent left-handedness are placed on a continuum mirroring the normal variation in rate of brain maturation. Maturational rate declines as we pass from PT leftward bias and consistent right-handedness to PT reversal and consistent left-handedness. Concomitantly, we expect an increased prevalence of males due to their pubertal age being about 2 years later than that of females, and a shift in cognitive profile from higher verbal scores than performance scores on the WAIS to higher performance than verbal scores. Three disorders fulfilling the criteria of late CNS maturation apart from the corresponding cognitive profile were studied: infantile autism (IA), schizophrenia (S), and developmental dyslexia (DD). These disorders have in common deficits in cognition, perception, and somatomotor function. The deficits range from an arrest in brain development (which is evident in infancy superimposed on late maturation in IA) to overall delayed brain and somatic development in S (culminating in postpubertal psychotic episodes and persistent and generalized residual deficits). Finally, reading inability, problems in perception (vision and hearing) and in motor coordination, particularly between the two hemispheres, characterize DD. Enhancing brain maturation and the prevalence of 'normal' cerebral asymmetry--laterality is preferable if we want to reduce the risk of developing the above-mentioned disorders. It is suggested that in the past environmental challenges have favored early maturation, with its abundant neuronal population, arborization and excessive density of synapses and cerebral excitability which has powered evolution through the mechanism of natural selection. Early maturation is obtainable through optimal nutrition, including a satisfactory amount of marine fat (PUFA), before and during pregnancy and later in life.

Autistic Disorder↗
PubMed1994

Genetic analysis of systematic mitochondrial heteroplasmy in rabbits.

One unusual property of rabbit mitochondrial DNA (mtDNA) is the existence of repeated 153-bp motifs in the vicinity of the replication origin of its H strand. Furthermore, every individual is heteroplasmic: it carries mtDNA molecules with a variable number of repeats. A systematic study of 8 females and their progeny has been devised to analyze mtDNA transmission through generations. The results suggest that three mechanisms are acting simultaneously. (1) Genetic drift in the germ line is revealed by the evolution of heteroplasmy when two major molecular forms are present in a female. (2) A high mutation rate (around 10(-2) per animal generation) generating molecular diversity, by deletion and addition of repeated units, is required to explain the observation of heteroplasmy in every individual. Moreover, the rates of mutation from the most frequent type to the other types are unequal. The deletion of one unit is more frequent than a deletion of two units, which is in turn more frequent than a deletion of three. (3) Selection for shorter molecules in somatic cells is probable. The frequency distribution of mtDNA types depends on the organ analyzed (kidney-spleen and liver vs. gonads).

Animals↗
PubMed1998

Key aspects of the primary sex determination mechanism are conserved across the genus Drosophila.

In D. melanogaster, a set of 'X:A numerator genes', which includes sisterlessA (sisA), determines sex by controlling the transcription of Sex-lethal (Sxl). We characterized sisA from D. pseudoobscura and D. virilis and studied the timing of sisA and Sxl expression with single cell-cycle resolution in D. virilis, both to guide structure-function studies of sisA and to help understand sex determination evolution. We found that D. virilis sisA shares 58% amino acid identity with its melanogaster ortholog. The identities confirm sisA as an atypical bZIP transcription factor. Although virilis sisA can substitute for melanogaster sisA, the protein is not fully functional in a heterologous context. The putative sisA regulatory sequence CAGGTAG is a potential 'numerator box,' since it is shared with the other strong X:A numerator gene, sisB, and its target, SxlPe. Temporal and spatial features of sisA and SxlPe expression are strikingly conserved, including rapid onset and cessation of transcription in somatic nuclei, early cessation of sisA transcription in budding pole cells and persistent high-level sisA expression in yolk nuclei. Expression of sisA and Sxl is as tightly coupled in virilis as it is in melanogaster. Taken together, these data indicate that the same primary sex determination mechanism exists throughout the genus Drosophila.

Amino Acid Sequence↗
PubMed2026

Selective Inhibition of DNA Polymerase Proofreading: A Metabolic-Fidelity Mechanism Explains Agent Orange-Associated Myelodysplasia.

We performed a focused review to better understand the pathogenesis of Agent Orange (AO)-associated myelodysplastic syndrome (MDS). We first examined the mechanisms underlying conventional (de novo) MDS, a clonal hematopoietic neoplasm that typically develops in later life, and integrated these findings with our recent analysis of obesity-associated carcinogenesis. Accordingly, we propose that genomic instability in de novo MDS results from selective inhibition of the DNA polymerase proofreading exonuclease. In obesity-associated carcinogenesis, impaired AMP-activated protein kinase (AMPK) activity disrupts mitochondrial ATP production, increasing intracellular AMP concentrations. Elevated AMP selectively inhibits the proofreading exonuclease while preserving polymerase activity, allowing replication errors to escape correction and become fixed as somatic mutations. Molecular studies demonstrate that AO-associated MDS exhibits essentially the same mutational profile as de novo disease despite arising after 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure in young, otherwise healthy military personnel. Because TCDD is highly lipophilic, it accumulates in adipose tissue and is released slowly over decades, producing sustained mitochondrial dysfunction, reduced ATP synthesis, and chronic elevation of intracellular AMP. We propose that this metabolic disturbance converges on the same endpoint-selective inhibition of the proofreading exonuclease-thereby promoting mutagenesis and clonal evolution. Recent studies further strengthen the central role of proofreading by demonstrating that many mutations, including many found in MDS, previously attributed to spontaneous cytosine deamination, instead arise from DNA polymerase misincorporation of thymidine opposite cytosine, particularly at CpG dinucleotides, emphasizing the critical importance of fully active proofreading in preventing such misincorporations from accumulating as mutations in the genome of the cell.

AMP↗
PubMed2003

Nuclear DNA content variation and species relationships in the genus Lupinus (Fabaceae).

The 2C nuclear DNA content has been estimated by flow cytometry in 18 species and botanical forms of the genus Lupinus (family Fabaceae), using propidium iodide as a fluorescent dye. They represented distinct infrageneric taxonomic groups and differed in somatic chromosome numbers. Estimated 2C DNA values ranged from 0.97 pg in L. princei to 2.44 pg in L. luteus, which gives a more than 2.5-fold variation. Statistical analysis of the data obtained resulted in a grouping that supports the generally accepted taxonomic classification of the Old World lupins. The rough-seeded L. princei turned out to be an interesting exception, getting closer to smooth-seeded species. Results of DNA content analyses are discussed with regards to the phylogenetic relationships among the Old World lupins and some aspects of the evolution of the genus.

Cell Nucleus↗