SEARCH · Search PubMed

Results for “Minor: Evolution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources

PubMed1994

The RNA polymerase I transcription factor UBF is a sequence-tolerant HMG-box protein that can recognize structured nucleic acids.

Upstream Binding Factor (UBF) is important for activation of ribosomal RNA transcription and belongs to a family of proteins containing nucleic acid binding domains, termed HMG-boxes, with similarity to High Mobility Group (HMG) chromosomal proteins. Proteins in this family can be sequence-specific or highly sequence-tolerant binding proteins. We show that Xenopus UBF can be classified among the sequence-tolerant class. Methylation interference assays using enhancer DNA probes failed to reveal any critical nucleotides required for UBF binding. Selection by UBF of optimal binding sites among a population of enhancer oligonucleotides with randomized sequences also failed to reveal any consensus sequence. The minor groove specific drugs chromomycin A3, distamycin A and actinomycin D competed against UBF for enhancer binding, suggesting that UBF, like other HMG-box proteins, probably interacts with the minor groove. UBF also shares with other HMG box proteins the ability to bind synthetic cruciform DNA. However, UBF appears different from other HMG-box proteins in that it can bind both RNA (tRNA) and DNA. The sequence-tolerant nature of UBF-nucleic acid interactions may accommodate the rapid evolution of ribosomal RNA gene sequences.

Animals↗

PubMed1989

Mineralization of Surfactants by Microbiota of Aquatic Plants.

The biodegradation of linear alkylbenzene sulfonate (LAS) and linear alcohol ethoxylate (LAE) by the microbiota associated with duckweed (Lemna minor) and the roots of cattail (Typha latifolia) was investigated. Plants were obtained from a pristine pond and a pond receiving wastewater from a rural laundromat. Cattail roots and duckweed plants were incubated in vessels containing sterile water amended with [C]LAS, [C]LAE, or C-labeled mixed amino acids (MAA). Evolution of CO(2) was determined over time. The microbiota of cattail roots from both ponds mineralized LAS, LAE, and MAA without lag periods, and the rates and extents of mineralization were not significantly affected by the source of the plants. Mineralization of LAS and LAE was more rapid in the rhizosphere than in nearby root-free sediments, which exhibited differences as a function of pond. The microbiota of duckweed readily mineralized LAE and MAA but not LAS. The rate and extent of mineralization were not affected by the source of the duckweed.

Journal Article↗

PubMed1995

Characterization of the five replication factor C genes of Saccharomyces cerevisiae.

Replication factor C (RFC) is a five-subunit DNA polymerase accessory protein that functions as a structure-specific, DNA-dependent ATPase. The ATPase function of RFC is activated by proliferating cell nuclear antigen. RFC was originally purified from human cells on the basis of its requirement for simian virus 40 DNA replication in vitro. A functionally homologous protein complex from Saccharomyces cerevisiae, called ScRFC, has been identified. Here we report the cloning, by either peptide sequencing or by sequence similarity to the human cDNAs, of the S. cerevisiae genes RFC1, RFC2, RFC3, RFC4, and RFC5. The amino acid sequences are highly similar to the sequences of the homologous human RFC 140-, 37-, 36-, 40-, and 38-kDa subunits, respectively, and also show amino acid sequence similarity to functionally homologous proteins from Escherichia coli and the phage T4 replication apparatus. All five subunits show conserved regions characteristic of ATP/GTP-binding proteins and also have a significant degree of similarity among each other. We have identified eight segments of conserved amino acid sequences that define a family of related proteins. Despite their high degree of sequence similarity, all five RFC genes are essential for cell proliferation in S. cerevisiae. RFC1 is identical to CDC44, a gene identified as a cell division cycle gene encoding a protein involved in DNA metabolism. CDC44/RFC1 is known to interact genetically with the gene encoding proliferating cell nuclear antigen, confirming previous biochemical evidence of their functional interaction in DNA replication.

Amino Acid Sequence↗

PubMed1996

Chronic B-cell lymphocytosis with binucleated lymphocytes (LWBL): a review of 38 cases.

LWBL is characterized by persistent and stable lymphocytosis, seen in but not exclusively female patients, with binucleated lymphocytes evident on peripheral blood smears. There is a polyclonal increase of serum IgM and in all cases immunophenotyping revealed a polyclonal expansion of B-lymphocytes. Whether this syndrome represents a premalignant disease process or a true polyclonal lymphocytosis remains unsettled. The occasional reports of clonal Ig rearrangements in this disorder suggest that in a minority of cases the polyclonal expansion may be followed by the emergence of one predominant clone. The demonstration of a clinically, benign, clonal lymphoid population is well recognised in several T cell disorders such as in the syndrome of large granular lymphocytes expansion. The benign clinical course and the lack of biological evolution in the majority of cases suggest that the importance of recognition of this disorder lies in avoiding aggressive therapy in these cases. A careful follow-up of these patients is mandatory and prospective immunological and genetic studies performed at different stages of the disease may well clarify this issue, particularly since most patients were HLA-DR7 positive.

Adult↗

PubMedDate not supplied

Capillaroscopic observations in childhood rheumatic diseases and healthy controls.

OBJECTIVE: To describe, by using video nailfold capillaroscopy (NFC), microvascular abnormalities in children with rheumatic diseases and to evaluate the capillary changes over a follow up period. METHODS: 118 children suffering from rheumatic diseases: 55 juvenile idiopathic arthritis (JIA), 7 mixed connective tissue disease (MCTD), 6 primary Raynaud's phenomenon (PRP), 34 systemic lupus erythematosus (SLE), 8 juvenile systemic sclerosis (JSSc) and 8 juvenile dermatomyositis (JDM) were included in the study. Patients with major capillaries abnormalities or scleroderma pattern were followed up for at least 12 months. 70 age- and sex-matched healthy controls (HC) were also examined. RESULTS: In HC there was a significant correlation between age and capillary length (p = 0.001). JIA patients showed capillary number, size, shape and arrangement similar to HC. Minor abnormalities were frequently observed. The percentage of major abnormalities were significantly increased compared to HC in MCTD (p = 0.008), SLE (p = 0.0002) and JDM patients (p < 0.0001). 5/8 of JSSc had a scleroderma pattern from the onset of the disease. The serial observations in connective tissue diseases also showed that the evolution of capillaroscopic pattern was not unidirectional. In fact, in some nailfolds there was an increase in capillary loss and in avascular areas, whereas sometimes it remained stable on repeated examination. CONCLUSION: NFC can be used as a simple, inexpensive, non-invasive method to evaluate the microvascular abnormalities in childhood rheumatic conditions, and it may be useful in early recognition and monitoring scleroderma spectrum disorders.

Adult↗

PubMedDate not supplied

[Pharmacological treatment resistant schizophrenia].

In the clinical practice, there are three different terms to designate schizophrenic patients who do not improve with antipsychotic medication: treatment-resistant, treatment-refractory and non-respondent patients. Treatment resistance is neither a synonym of chronicity nor of severity nor seriousness. Therefore, for a patient to be considered resistant, several points must be taken into account. These points are: a) whether the schizophrenia is primary or secondary; b) its nature; c) presence of previous substance abuse; d) treatment compliance and tolerance, and presence of minor neurological signs. The most widely accepted criteria to define pharmacological treatment resistance in schizophrenia were initially developed around 1988 by Kane. Nowadays, the BPRS and Independent Living Skills Survey (ILSS) are the scales used to assess the levels of lack or response or of treatment resistance. To attain a suitable therapeutic evolution in schizophrenics resistant to treatment in antipsychotic medication assays, the following guidelines must be considered: Identifying the symptoms clearly and using medication with a suitable dose and duration. Taking into account that treatment resistance can be mistaken for treatment intolerance, non-compliance to treatment, inappropriate social support or inappropriate psychosocial treatment. Using up all single therapeutic agents before applying multiple agents. Preventing extrapyramidal effects by means of an adequate choice of the primary treatment. Maintaining a positive therapeutic attitude.

Antipsychotic Agents↗

PubMed1997

Age-related changes in phospholipid fatty acid composition and monoaminergic neurotransmission in the hippocampus of rats fed a balanced or an n-3 polyunsaturated fatty acid-deficient diet.

The influence of aging (2, 6, 12, and 24 months) on hippocampal lipid composition and neurochemical markers (endogenous noradrenaline, serotonin levels, monoamine oxidase (MOA) activities) was studied in rats fed a control or an n-3 polyunsaturated fatty acid (PUFA)-deficient diet. The n-3 PUFA deficiency reduced the 22:6 (n-3) level, compensated by the increase in 22:5 (n-6). However, the difference in 22:6 (n-3) content between control and deficient rats was less between 2 and 12 months and then became stable. There was an overall age-induced decrease in the major phospholipid classes phosphatidylethanolamine (PE), and phosphatidylcholine (PC) whereas the minor classes, phosphatidylinositol (PI), phosphatidylserine (PS), and sphingomyelin (SM), were greatly increased, regardless of diet. The n-3 PUFA deficiency induced a reduction in the PS level, concomitant with a higher level in MAO-B activity as compared to control rats at the age of 24 months. The age-related evolution of the MAO-B activity was parallel with that of noradrenaline levels in both dietary groups. The noradrenaline and serotonin levels were modified according to age but without effect of the n-3 PUFA deficiency. Results showed that the hippocampus sustained specific age-induced modifications in lipid composition and neurotransmission factors, often with a transition period between 6 and 12 months.

Aging↗

PubMed2006

Identification and characterization of a squamate reptilian amelogenin gene: Iguana iguana.

As the principal components of the developing tooth enamel matrix, amelogenins play a significant role in tooth enamel formation and organization. In order to elucidate the structure and function of amelogenins in the evolution of enamel, we have selected the Iguana iguana as a squamate model organism. Here we report the first complete squamate amelogenin sequence available as of yet and document unique features of Iguana amelogenins and enamel. Transmission electron microscopy documented randomly oriented Iguana enamel crystals during the elongation phase compared with organized enamel crystal patterns at comparable stages in mammals. Sequencing of PCR amplified products revealed a full-length I. iguana amelogenin cDNA containing 877 nucleotides with a 564 nucleotide coding sequence encoding 187 amino acids. The homologies of the newly discovered I. iguana amelogenin amino acid sequence with the published mouse, caiman (Palaeosuchus), and snake (Elaphe) amelogenin were 41.3%, 53.5%, and 55.5%, respectively. On Western blots one major protein with a molecular weight of 24 kDa, and two minor proteins with molecular weights of 28 and 13.5 kDa, respectively, were detected based on the cross-reactivity of antisera against recombinant Rana pipiens amelogenin proteins. Sequence analysis revealed a moderate sequence homology between mammalian and reptilian amelogenin genes. A significant alteration was the deletion of the hydrophilic GSP sequence from exon 3 in the mouse sequence resulting in a conversion to a hydrophobic region in Iguana. Together, these findings identified a novel amelogenin cDNA sequence in the squamate reptilian I. iguana and functional implications for the evolution of amelogenins and enamel in squamates.

Amelogenin↗

PubMed2025

Detecting Introgression in Shallow Phylogenies: How Minor Molecular Clock Deviations Lead to Major Inference Errors.

Recent theoretical and algorithmic advances in introgression detection, coupled with the growing availability of genome-scale data, have highlighted the widespread occurrence of interspecific gene flow across the tree of life. However, current methods largely depend on the molecular clock assumption-a questionable premise given empirical evidence of substitution rate variation across lineages. While such rate heterogeneity is known to compromise gene flow detection among divergent lineages, its impact on closely related taxa at shallow evolutionary timescales remains poorly understood, likely because these taxa are often assumed to adhere to a molecular clock. To address this gap, we combine theoretical analyses and simulations to evaluate the robustness of widely used site pattern methods (D-statistic and HyDe) to rate variation across phylogenetic timescales. Our results demonstrate that both methods exhibit high sensitivity to even minor deviations from the molecular clock at shallow timescales, complementing previous findings at deeper scales. Specifically, in young phylogenies (with an age of 3 × 105 generations) with small population sizes, weak (17% difference) and moderate (33% difference) rate variation can inflate false-positive rates up to 35% and 100%, respectively, using site pattern counts from a 500 Mb genome. Employing a more distant outgroup intensifies these spurious signals. Our study demonstrates that summary tests for introgression are pervasively vulnerable to minor rate variations and underscores the critical need for advanced methodologies to disentangle genuine introgression from false signals generated by rate heterogeneity.

Phylogeny↗

PubMed2000

Surgical outcome after paediatric cochlear implantation: diminution of complications with the evolution of new surgical techniques.

OBJECTIVE: Cochlear implantation is a commonly performed surgical procedure with specific aspects in the paediatric population. The surgical outcome associated with this procedure in a paediatric population is analyzed. METHOD: A retrospective study was performed of all children receiving a cochlear implant at The Hospital for Sick Children from 1990 to 1998. During this period, 104 patients received a cochlear implant. RESULTS: The complications encountered were classified as major (4%), minor (3%), and device failure (2%). The surgical techniques developed to decrease complications are discussed. CONCLUSION: Paediatric cochlear implantation is a safe procedure with a low incidence of complications. Nevertheless, the surgeon is now facing new challenges with cochlear implantation performed in patients with an abnormal cochlea, who carry a higher rate of complications, and cochlear reimplantation in case of device failure.

Adolescent↗

PubMed2003

Constraints on adaptive mutations in the codling moth Cydia pomonella (L.): measuring fitness trade-offs and natural selection.

Adaptive changes in populations encountering a new environment are often constrained by deleterious pleiotropic interactions with ancestral physiological functions. Evolutionary responses of populations can thus be limited by natural selection under fluctuating environmental conditions, if the adaptive mutations are associated with pleiotropic fitness costs. In this context, we have followed the evolution of the frequencies of insecticide-resistant mutants of Cydia pomonella when reintroduced into an untreated environment. The novel set of selective forces after removal of insecticide pressure led to the decline of the frequencies of resistant phenotypes over time, suggesting that the insecticide-adapted genetic variants were selected against the absence of insecticide (with a selective coefficient estimated at 0.11). The selective coefficients were also estimated for both the major cytochrome P450-dependent monooxygenase (MFO) and the minor glutathione S-transferase (GST) systems (0.17 and negligible, respectively), which have been previously shown to be involved in resistance. The involvement of metabolic systems acting both through xenobiotic detoxification and biosynthetic pathways of endogenous compounds may be central to explaining the deleterious physiological consequences resulting from pleiotropy of adaptive changes. The estimation of the magnitude of the fitness cost associated with insecticide resistance in C. pomonella suggests that resistance management strategies exclusively based on insecticide alternations would be unlikely to delay such a selection process.

Animals↗

PubMed2005

CD34+CD7+ leukemic progenitor cells may be involved in maintenance and clonal evolution of chronic myeloid leukemia.

PURPOSE: We analyzed CD34+ cells coexpressing CD7 in chronic myeloid leukemia (CML) in chronic phase (CP) or accelerated phase (AP) to clarify their role in progression or regression of the disease during treatment. EXPERIMENTAL DESIGN: Enumeration of CD34+CD7+ cells was done on bone marrow nucleated cells from normal donors and CML patients. Fluorescence in situ hybridization analysis was done on sorted CD34+CD7+and CD34+CD7- cells to examine the occupancy rate of each fraction by BCR-ABL+ cells with or without additional cytogenetic abnormalities. RESULTS: The proportion of CD34+CD7+cells was significantly affected by the treatment outcome and/or the disease status as follows: 20.5 +/- 10.4% in normal donors (n = 22), 18.1 +/- 10.2% in CP with major cytogenetic response (n = 14), 53.0 +/- 12.9% in CP at diagnosis (n = 18), 55.0 +/- 15.8% in CP with minor or no cytogenetic response (n = 28), and 70.2 +/- 18.1% in AP (n = 6). The proportion of CD34+CD7+cells decreased in parallel with cytogenetic improvement in individual patients. In six untreated CP patients, the ratio of BCR-ABL+ cells was comparable between each fraction. In three patients with major cytogenetic response, the ratio of BCR-ABL+ cells was remarkably lower in CD34+CD7- cells than in CD34+CD7+cells. In three AP patients with additional cytogenetic abnormalities, extra signals were detected at a much higher rate in CD34+CD7+ cells than in CD34+CD7- cells. CONCLUSIONS: Our results suggest that CD34+CD7+ cells may be involved in maintenance and clonal evolution of BCR-ABL+ cells in CML.

Adolescent↗

PubMed1993

Human papillomavirus infection and intraepithelial, in situ, and invasive carcinoma of penis.

The role of human papillomavirus (HPV) infection and other reported cofactors in the genesis, evolution, and clinical manifestations of precancerous and cancerous squamous cell lesions of the penis were studied in 34 men. Clinically, all lesions demonstrated aceto-whitening. Histologic changes of HPV infection formed a field-of-change that involved the components of the preputial cavity in all patients. These changes were associated with minor grades of penile intraepithelial neoplasia (PIN I and II) in 19 patients, major grades of PIN/carcinoma in situ (PIN III/Tis) in 7, and invasive squamous cell carcinoma (SCCa, Stages T2 and T3) in 8. Most of the patients (79.4%) were heavy smokers; 52.9 percent had a history of HPV infection, PIN, or invasive penile SCCa; and 60 percent of 30 patients had female sexual partners who had HPV-related genital neoplasia. A pilot virologic study of specimens obtained from 20 representative patients utilizing polymerase chain reaction amplification detected HPV DNA in 80 percent. Laser therapy was aimed at the entire field-of-change in 30 patients; recurrent minor-grade PIN or SCCa developed in 2 of 23 patients (8.7%) followed for up to three years. Of the 4 remaining patients treated with local excision or partial penectomy, 3 (75%) had development of recurrent minor-grade PIN when followed for up to four years. The combination of the host of carcinogenic factors and currently rampant immunologic disorders will likely lead to an increase in the historically low incidence of SCCa of the penis in the United States.

Adult↗

PubMed1993

The disposition of acrylic acid in the male Sprague-Dawley rat following oral or topical administration.

The disposition of [1-14C] acrylic acid (AA) was characterized in the male Sprague-Dawley rat following oral administration, by gavage in water, at 400 mg/kg and topical application, in acetone, at 501 micrograms/cm2. The oral dose was well absorbed, rapidly and extensively metabolized, and excreted primarily (approx. 80%) as 14CO2 within 24 hr of administration. The rate and extent of 14CO2 evolution from [14C]AA was greater for [1-14CAA] while a significantly lower proportion of the dosed radioactivity remained in the tissue of animals than that reported for [2,3-14C]AA (Winter et al., Drug Metabolism and Disposition 1992, 20, 665). This is consistent with incorporation of AA into a minor beta-oxidation pathway of mitochondrial propionate metabolism by which AA may be metabolized to CO2 or incorporated into cellular constituents. Approximately 5% of the dosed radioactivity was excreted in the urine. The disposition of [1-14C]AA following dermal application was studied using charcoal-containing traps attached to the back of the rats to trap volatilized AA from the dosing sites. Following application of 100 microliters AA [4% (v/v) in acetone] to an area of 8.4 cm2 of the skin of a rat (501 micrograms/cm2), the majority (about 73%) of the dose volatilized and was recovered in the charcoal trap. Percutaneous absorption of AA that did not volatilize was rapid and appeared to have the same metabolic fate as AA administered orally with about 75% of the absorbed dose excreted as 14CO2 within 24 hr.

Acrylates↗

PubMed2006

Imatinib resistant chronic myelogenous leukemia, BCR-ABL positive by chromosome and FISH analyses but negative by PCR, in a child progressing to acute basophilic leukemia: cytogenetic follow-up.

The case of an 11-year-old child with adult-type chronic myeloid leukemia, Philadelphia (BCR-ABL) positive, reverse transcription-polymerase chain reaction negative for the major, minor, and micro breakpoints is presented. In the course of 3 years, the child failed to respond to treatment with hydroxyurea, refused all therapy for 6 months, was intolerant to alpha-interferon and progressed, while on imatinib, to acute basophilic leukemia. Subsequently he underwent successful bone marrow transplantation. A secondary cytogenetic clonal evolution, i(17q), developed during hydroxyurea treatment and a tertiary clonal evolution, +8, was detected during imatinib treatment. It is not clear to what extent the several factors (undefined BCR-ABL breakpoint, treatment avoidance, and initial treatment choices, alone or in combination) played a role in the imatinib relapse and resistance and in the disease progression. We conclude that close follow-up with frequent bone marrow sampling is crucial in order to monitor such patients for early relapse and prompt referral for bone marrow transplant.

Antineoplastic Agents↗

PubMed2004

Australian funnel-web spiders: master insecticide chemists.

Arthropods are the most diverse animal group on the planet. Their ability to inhabit a vast array of ecological niches has inevitably brought them into conflict with humans. Although only a small minority are classified as pest species, they nevertheless destroy about a quarter of the world's annual crop production and transmit an impressive array of pathogens of human and veterinary public health importance. Arthropod pests have been controlled almost exclusively with chemical insecticides since the introduction of DDT in the 1940s. However, the evolution of resistance to many insecticides, coupled with increased awareness of the potential environmental and human and animal health impacts of these chemicals, has stimulated the search for new insecticidal compounds, novel molecular targets, and alternative control methods. Spider venoms are complex chemical cocktails that have evolved to kill or paralyze arthropod prey, and they represent a largely untapped reservoir of insecticidal compounds. This review focuses on several families of invertebrate-specific peptide neurotoxins that were isolated from the venom of Australian funnel-web spiders. These peptides are promising insecticide leads because of their selectivity for invertebrates and activity on previously unvalidated targets. These toxins should facilitate the development of novel target-based screens for new insecticide leads, while their mapped pharmacophores will provide templates for rational design of mimetics that act at these target sites. Furthermore, genes encoding these toxins can be used to improve the efficacy of insect-specific viruses.

Amino Acid Sequence↗

PubMed2006

Detection of T lymphocytes specific for human endogenous retrovirus K (HERV-K) in patients with seminoma.

Human endogenous retrovirus K (HERV-K) is distinctive among the retroviruses that comprise about 8% of the human genome in that multiple HERV-K proviruses encode full-length viral proteins, and many HERV-K proviruses formed during recent human evolution. HERV-K gag proteins are found in the cytoplasm of primary tumor cells of patients with seminoma. We identified HERV-K-specific T cells in patients with a past history of seminoma using the interferon-gamma ELISPOT assay and an MHC-HERV-K peptide-specific tetramer. A minority of apparently healthy subjects without evident germ cell tumors also made HERV-K-specific T cell responses. In summary, we detected T cell reactivity to HERV-K peptides in both past seminoma patients and a minority of apparently healthy controls.

Antibodies, Viral↗

PubMed2006

[Old and new materials in the hip prosthesis].

Since the second half of the XX century a steady evolution of hip prosthesis design is taking place. Implant shape, fixation systems and materials are constantly evolving. The paper presents the materials combinations most commonly used in hip prosthesis (metal-metal, metal-polyethylene and ceramic). All the above mentioned materials have been in used for over 25 years, and thanks to minor modification and better quality are widely used all over the world. The authors basing on biochemical studies, clinical observations and personal experience present problems related to materials used in hip prosthesis.

Arthroplasty, Replacement, Hip↗