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At least 451 records · Page 25Linked to original sources
PubMed1999

Calcium homeostasis in crustacea: the evolving role of branchial, renal, digestive and hypodermal epithelia.

Crustaceans serve as an ideal model for the study of calcium homeostasis due to their natural molting cycle. Demineralization and remineralization of the calcified cuticle is accompanied by bidirectional Ca transfer across the primary Ca transporting epithelia: gills, antennal gland (kidney), digestive system, and cuticular hypodermis. The review will demonstrate how a continuum of crustaceans can be used as a paradigm for the evolution of Ca transport mechanisms. Generally speaking, aquatic crustaceans rely primarily on branchial Ca uptake and accordingly are affected by water Ca content; terrestrial crustaceans rely on intake of dietary Ca across the digestive epithelium. Synchrony of mineralization at the cuticle vs. storage sites will be presented Physiological and behavioral adaptations have evolved to optimize Ca balance during the molting cycle in different Ca environments. Intracellular Ca regulation reveals common mechanisms of apical and basolateral membrane transport as well as intracellular sequestration. Regulation of cell Ca concentration will be discussed in intermolt and during periods of the molting cycle when transepithelial Ca flux is significantly elevated. Molecular characterization of the sarco-/endoplasmic reticular Ca pump in aquatic species reveals the presence of two isoforms that originate from a single gene. This gene is differentially expressed during the molting cycle. Gene expression may be regulated by a suite of hormones including ecdysone, calcitonin, and vitamin D. Perspectives for future research are presented.

Animals↗
PubMed1999

Evolving ideals of male body image as seen through action toys.

OBJECTIVE: We hypothesized that the physiques of male action toys--small plastic figures used by children in play--would provide some index of evolving American cultural ideals of male body image. METHOD: We obtained examples of the most popular American action toys manufactured over the last 30 years. We then measured the waist, chest, and bicep circumference of each figure and scaled these measurements using classical allometry to the height of an actual man (1.78 m). RESULTS: We found that the figures have grown much more muscular over time, with many contemporary figures far exceeding the muscularity of even the largest human bodybuilders. DISCUSSION: Our observations appear to represent a "male analog" of earlier studies examining female dolls, such as Barbie. Together, these studies of children's toys suggest that cultural expectations may contribute to body image disorders in both sexes.

Adult↗
PubMed1981

Angioimmunoblastic lymphadenopathy with dysproteinemia: report of the first case in childhood evolving toward spontaneous remission.

This is the first known report of a case of angioimmunoblastic lymphadenopathy, with dysproteinemia (AILD) in childhood which evolved toward a spontaneous remission. The disease had an acute onset with generalized lymphadenopathy, hepatosplenomegaly, high-grade fever and polyclonal hypergammaglobulinemia. The lymph nodes met all of the histologic criteria required for diagnosis as established by Frizzera et al. It is emphasized that AILD should be taken into consideration in the differential diagnosis of lymphadenopathy in childhood.

Child↗
PubMed1994

Pyothorax-associated pleural lymphoma. A case evolving from T-cell-rich lymphoid infiltration to overt B-cell lymphoma in association with Epstein-Barr virus.

BACKGROUND: Pyothorax-associated pleural lymphomas (PAPL) occur in patients with long-standing pyothorax. Epstein-Barr virus (EBV) plays an important role in its development. METHODS: An atypical case of PAPL is reported and its clinical features are compared with those of five cases of ordinary PAPL. RESULTS: The histology of the lymphoma changed from prominent T-cell infiltration to an overt B-cell lymphoma of diffuse, large cell-type. DNA studies of the lymphoma at the first presentation demonstrated dual rearrangement in the T-cell receptor beta (TCR beta) and immunoglobulin heavy chain J region (IgJH) genes. EBV genome analysis demonstrated monoclonal expansion of EBV-infected cells. EBV gene products were present only in large lymphocytes with B-cell phenotype. The same rearranged band of the IgJH gene, but not clonal rearrangement of the TCR beta gene, was observed in the overt B-cell lymphoma at the relapse. The same EBV-infected clone was observed throughout the course of the disease. The tumor was localized at the pyothorax wall, and cell-mediated immunity, reflected by a positive tuberculin reaction, was preserved only in the current case. CONCLUSIONS: T-cell-rich lymphoid infiltration in the current case is a variant of EBV-associated PAPL, which is infiltrated by reactive T-cells with clonal accentuation. This is the first documented case of EBV-associated PAPL evolving from T-cell-rich lymphoid infiltration.

Aged↗
PubMed2001

Abalone lysin: the dissolving and evolving sperm protein.

Abalone sperm lysin is a non-enzymatic protein that creates a hole for sperm passage in the envelope surrounding the egg. Lysin exhibits species-specificity in making the hole and it evolves rapidly by positive selection. Our studies have focused on combining structural, biochemical, and evolutionary data to understand the mechanism of action and evolution of this remarkable protein. Currently, more is known about lysin than about any other protein involved in animal fertilization. We present an hypothesis to explain lysin's rapid evolution and the evolution of species-specific fertilization in this order of mollusks. We also propose a two-step model for lysin's action in which a dimer of lysin binds species-specifically to its glycoprotein receptor, and then monomerizes and binds the receptor in a non-species-specific manner. This experimental system yields data relevant to the general problem of molecular recognition between cell surfaces, and is also important to our thinking about how new species arise in the sea. BioEssays 23:95-103, 2001.

Acrosome↗
PubMed2002

Provisional new syndrome of MR/MCA with evolving phenotype.

We report on a 10-year-old patient with a provisionally new syndrome of MR/MCA with an evolving phenotype. Major findings at birth included short umbilical cord; striking hypotonia and cutis laxa with increased OFC; facial abnormalities with epicanthal folds, telecanthus, mild hypertelorism, wide flat nasal bridge, hypoplastic nose with upturned nostrils, and low-set dysplastic ears; asymmetric deformed chest with prominent sternum and winged scapulae; wider thumbs and halluces; left cryptorchidism and unusual perianal creases. Chromosomal and metabolic studies were normal. With aging, the phenotype has changed significantly: cutis laxa disappeared, the perianal creases and hypotonia are much milder, the initial apparent macrocephaly turned out to be true microcephaly, broad thumbs are less evident, but skeletal anomalies are more striking. Unsuccessful extensive diagnostic searches since birth and presentation in meetings suggest the presence of a private syndrome.

Abnormalities, Multiple↗
PubMed2007

Histone H1-like, lysine-rich low complexity amino acid extensions in mosquito ribosomal proteins RpL23a and RpS6 have evolved independently.

Histone H1-like amino acid extensions have been described at the amino terminus of Drosophila RpL22 and RpL23a, and at the carboxyl terminus of mosquito ribosomal protein RpS6. An in silico search suggested that RpL23a, but not RpL22, in Anopheles gambiae has an amino-terminal extension. Because low complexity amino acid extensions are not common on eukaryotic ribosomal proteins, and their functions are unknown, we cloned cDNAs encoding RpL23a from Aedes albopictus and Anopheles stephensi mosquito cell lines. RpL23a proteins in Aedes and Anopheles mosquitoes are rich in lysine (approximately 25%), alanine (approximately 21%), and proline (approximately 8%), have a mass of approximately 40 kDa, a pI of 11.4 to 11.5, and contain an N-terminal extension of approximately 260 amino acid residues. The N-terminal extension in mosquito RpL23a is about 100 amino acids longer than that in the Drosophila RpL23a homolog, and contains several repeated amino acid motifs. Analysis of exon-intron organization in the An. gambiae and in D. melanogaster genes suggests that a short first exon encodes a series of 11 amino acid residues conserved in RpL23a proteins from Drosophila, mosquitoes, and the moth, Bombyx mori. The histone H1-like sequence in RpL23a is encoded entirely within the second exon. The C-terminal 126 amino acid residues of the RpL23a protein, encoded by exon 3 in Drosophila, and by exons 3 and 4 in Anopheles gambiae, are well conserved, and correspond to Escherichia coli RpL23 with the addition of the eukaryotic N-terminal nuclear localization sequence. Sequence comparisons indicate that the histone H1-like extensions on mosquito RpS6 and RpL23a have evolved independently of each other, and of histone H1 proteins.

3' Untranslated Regions↗
PubMed2001

Cancer: the evolved consequence of a destabilized genome.

The genome is a stable repository of vastly intricate genetic information developed over eons of evolution; this information is replicated at the highest fidelity and expressed within each cell at the highest selectivity. Non-leukemia cancers break this standard; the intricate genetic information qualitatively and progressively deteriorates, resulting in a somatic Darwinian free-for-all. In a process lasting several years, a genomically heterogeneous population replicates from a single cell that originally lost the ability to preserve its genomic integrity. Cells selected for their abilities to proliferate and spread, while evading host defenses, inexorably expand their numbers. The clinical consequences of this become severe, as the genomically diverse cell population that evolves contains members that can evade most therapeutic approaches aimed at "the tumor cell".

Animals↗
PubMed1995

The origin and function of the mammalian Y chromosome and Y-borne genes--an evolving understanding.

Mammals have an XX:XY system of chromosomal sex determination in which a small heterochromatic Y controls male development. The Y contains the testis determining factor SRY, as well as several genes important in spermatogenesis. Comparative studies show that the Y was once homologous with the X, but has been progressively degraded, and now consists largely of repeated sequences as well as degraded copies of X linked genes. The small original X and Y have been enlarged by cycles of autosomal addition to one partner, recombination onto the other and continuing attrition of the compound Y. This addition-attrition hypothesis predicts that the pseudoautosomal region of the human X is merely the last relic of the latest addition. Genes (including SRY) on the conserved or added region of the Y evolved functions in male sex determination and differentiation distinct from the general functions of their X-linked partners. Although the gonadogenesis pathway is highly conserved in vertebrates, its control has probably changed radically and rapidly in vertebrate--even mammalian--evolution.

Animals↗
PubMed1996

Is the Y chromosome of Drosophila an evolved supernumerary chromosome?

The Y chromosomes of most Drosophila species are necessary for male fertility but they are not involved in sex determination. They have many puzzling properties that resemble the effects caused by B chromosomes. Classical genetic and molecular studies reveal substantial affinities between Y and B chromosomes and suggest that the Y chromosomes of Drosophila are not degenerated homologues of the X chromosomes, but rather that their Y chromosomes evolved as specialized supernumeraries similar to classical B chromosomes.

Animals↗
PubMed2006

Enantioconvergent production of (R)-1-phenyl-1,2-ethanediol from styrene oxide by combining the Solanum tuberosum and an evolved Agrobacterium radiobacter AD1 epoxide hydrolases.

Soluble epoxide hydrolase (EH) from the potato Solanum tuberosum and an evolved EH of the bacterium Agrobacterium radiobacter AD1, EchA-I219F, were purified for the enantioconvergent hydrolysis of racemic styrene oxide into the single product (R)-1-phenyl-1,2-ethanediol, which is an important intermediate for pharmaceuticals. EchA-I219F has enhanced enantioselectivity (enantiomeric ratio of 91 based on products) for converting (R)-styrene oxide to (R)-1-phenyl-1,2-ethanediol (2.0 +/- 0.2 micromol/min/mg), and the potato EH converts (S)-styrene oxide primarily to the same enantiomer, (R)-1-phenyl-1,2-ethanediol (22 +/- 1 micromol/min/mg), with an enantiomeric ratio of 40 +/- 17 (based on substrates). By mixing these two purified enzymes, inexpensive racemic styrene oxide (5 mM) was converted at 100% yield to 98% enantiomeric excess (R)-1-phenyl-1,2-ethanediol at 4.7 +/- 0.7 micromol/min/mg. Hence, at least 99% of substrate is converted into a single stereospecific product at a rapid rate.

Agrobacterium tumefaciens↗
PubMed1990

Free radical inhibition and serial chemiluminescence in evolving experimental pancreatitis.

Oxygen free radical activity and inhibition were examined in experimental pancreatitis. Twenty-five rats were randomized to five groups: controls received intravenous saline, to simulate pancreatitis one group received intravenous caerulein (5 micrograms kg-1 h-1), and three groups received sodium taurocholate via the pancreatic duct (0.2 ml, 5 per cent), either alone, following allopurinol or immediately before superoxide dismutase. Chemiluminescence (a phenomenon based on the emission of light during chemical reactions and which is dependent on oxygen free radical activity) was used as an index of oxygen free radical activity and was measured in tissue samples at 5-min intervals following induction of pancreatitis. The control mean(s.e.m.) serum amylase level 1 h after induction of pancreatitis was 635(13) units. It was significantly elevated in caerulein-induced pancreatitis, 1833(118) units (P less than 0.05) and exceeded 3000 units in all taurocholate-infused animals. Mean(s.e.m.) chemiluminescence ranged from 44 (8) mV 100 mg-1 at time zero to 404(113) mV 100 mg-1 at 1 h in controls. In caerulein-induced pancreatitis mean(s.e.m.) chemiluminescence peaked at 20 min (1399(239) mV 100 mg-1, P less than 0.02) and in taurocholate-induced pancreatitis at 15 min (2316(95) mV 100 mg-1, P less than 0.004). Superoxide dismutase significantly reduced chemiluminescence and hyperamylasaemia in taurocholate groups. Increasing oxygen free radical activity paralleled evolving pancreatitis. Superoxide dismutase may have a therapeutic role in pancreatitis.

Allopurinol↗
PubMed2006

O-O bond formation in the S(4) state of the oxygen-evolving complex in photosystem II.

Based on recent X-ray structures of the oxygen-evolving complex in photosystem II, quantum chemical geometry optimizations of several thousand structures have been performed in order to elucidate the mechanism for dioxygen formation. Many of the results of these calculations have been presented previously. The energetically most stable structure of the S(4) state has been used in the present study to investigate essentially all the possible ways the O--O bond can be formed in this structure. A key feature, emphasized previously, of the S(4) state is that an oxygen radical ligand is present rather than an Mn(V) state. Previous studies have indicated that this oxygen radical can form an O--O bond by an attack from a water molecule in the second coordination shell. The present systematic investigation has led to a new type of mechanism that is significantly favored over the previous one. A calculated transition-state barrier of 12.5 kcal mol(-1) was found for this mechanism, whereas the best previous results gave 18-20 kcal mol(-1). A requirement on the spin alignment for a low barrier is formulated.

Journal Article↗
PubMed2003

Cancer-related fatigue: evolving concepts in evaluation and treatment.

BACKGROUND: Although fatigue is one of the most common complaints of patients with cancer, it went unrecognized or overlooked for many years, until clinicians achieved better control over the more acute symptoms of nausea, emesis, and pain. A number of treatment-related and disease-related factors may contribute to the development of fatigue, but its physiologic basis remains poorly understood, and many proposed interventions have not been studied systematically. The lack of a standard of care for the assessment or treatment of fatigue in patients with cancer has limited research in this field. A critical appraisal of these issues is presented in this review. METHODS: The published literature was reviewed for definition, prevalence, causes, and means of managing cancer-related fatigue (CRF). RESULTS: Fatigue was reportedly present at the time of diagnosis in approximately 50-75% of cancer patients. The prevalence of CRF increased to 80-96% in patients undergoing chemotherapy and to 60-93% in patients receiving radiotherapy. Two tested interventions that showed consistent effects to alleviate CRF were treatment of cancer-related anemia with erythropoietin agents (recombinant human erythropoietin and darbepotin alpha) and aerobic exercise. CONCLUSIONS: Several lines of research are needed to bridge the specific gaps in the current knowledge of CRF. These involve the pathophysiology of the symptom, the validation of diagnostic criteria, and specific therapeutic interventions. Current practice guidelines are based on a combination of research and expert clinical judgment and should be used to guide care with the expectation that they will evolve to incorporate the results of studies currently underway.

Antineoplastic Agents↗
PubMed1994

Replacement of an inherited stretch receptor by a newly evolved stretch receptor in hippid sand crabs.

Primary sensory neurons that are motoneuron-like in morphology and often nonspiking (transmit afferent signals as graded depolarizations) characterize an unusual type of stretch receptor in decapod crustaceans. Nonspiking and spiking receptors occur in similar positions at homologous joints in different species and have been presumed to be homologous, the spiking one considered "primitive". To better understand the evolutionary origin of these stretch receptors and why some are nonspiking, we examined the spiking telson-uropod stretch receptors in the spiny sand crab Blepharipoda occidentalis (Albuneidae) and the squat lobster Munida quadrispina (Galatheidae) and compared them with the nonspking telson-uropod stretch receptor of the mole sand crab Emerita analoga (Hippidae). The position, morphology and responses to stretch of the sensory neurons, and the ultrastructure of the elastic strand portion of the receptor are similar in M. quadrispina and B. occidentalis, except that in B. occidentalis the receptor muscles are substantially smaller and the extracellular matrix of the elastic receptor strand is both more extensive and more organized, reminiscent of the ultrastructure of E. analoga's nonspiking receptor. We conclude that the spiking telson-uropod stretch receptors of albuneids and galatheids are homologous. The differences in the ultrastructure of their receptor strands imply that the efficiency of coupling receptor length change to deformation of the dendritic termini increases in the order M. quadrispina < B. occidentalis < E. analoga. The spiking and nonspiking telson-uropod stretch receptors differ anatomically in three major respects that appear to preclude their homology. (1) The receptor strands are on opposite sides of a conserved muscle. (2) The sensory somata are in different regions of the sixth abdominal ganglion: a lateral cluster of somata for the spiking sensory neurons and two medial clusters, one anterior, one posterior, for the nonspiking sensory neurons. (3) The neuropil projections of the sensory neurons are different. We conclude that the hippid's nonspiking telson-uropod stretch receptor evolved de novo and not by modification of the ancestral anomuran telson-uropod stretch receptor (which Hippidae have lost).

Action Potentials↗
PubMed2004

Comparative genomics of the Mill family: a rapidly evolving MHC class I gene family.

Mill (MHC class I-like located near the leukocyte receptor complex) is a novel family of class I genes identified in mice that is most closely related to the human MICA/B family. In the present study, we isolated Mill cDNA from rats and carried out a comparative genomic analysis. Rats have two Mill genes orthologous to mouse Mill1 and Mill2 near the leukocyte receptor complex, with expression patterns similar to those of their mouse counterparts. Interspecies sequence comparison indicates that Mill is one of the most rapidly evolving class I gene families and that non-synonymous substitutions occur more frequently than synonymous substitutions in its alpha 1 domain, implicating the involvement of Mill in immune defenses. Interestingly, the alpha 2 domain of rat Mill2 contains a premature stop codon in many inbred strains, indicating that Mill2 is not essential for survival. A computer search of the database identified a horse Mill-like expressed sequence tag, indicating that Mill emerged before the radiation of mammals. Hence, the failure to find Mill in human indicates strongly that it was lost from the human lineage. Our present work provides convincing evidence that Mill is akin to the MICA/B family, yet constitutes a distinct gene family.

Amino Acid Sequence↗
PubMed2004

Infevers: an evolving mutation database for auto-inflammatory syndromes.

The Infevers database (http://fmf.igh.cnrs.fr/infevers/) was established in 2002 to provide investigators with access to a central source of information about all sequence variants associated with periodic fevers: Familial Mediterranean fever (FMF), TNF Receptor Associated Periodic Syndrome (TRAPS), Hyper IgD Syndrome (HIDS), Familial Cold Autoinflammatory Syndrome/Muckle-Wells Syndrome/Chronic Infantile Neurological Cutaneous and Articular Syndrome (FCAS/MWS/CINCA). The prototype of this group of disorders is FMF, a recessive disease characterized by recurrent bouts of unexplained inflammation. FMF is the pivotal member of an expanding family of autoinflammatory disorders, a new term coined to describe illnesses resulting from a defect of the innate immune response. Therefore, we decided to extend the Infevers database to genes connected with autoinflammatory diseases. We present here the biological content of the Infevers database, including the introduction of two new entries: Crohn/Blau and Pyogenic sterile arthritis, pyoderma gangrenosum and acne (PAPA syndrome). Infevers has a range of query capabilities, allowing for simple or complex interrogation of the database. Currently, the database contains 291 sequence variants in related genes (MEFV, TNFRSF1A, MVK, CARD15, PSTPIP1, and CIAS1), consisting of published data and personal communications, which has revealed or refined the preferential mutational sites for each gene. This database will continue to evolve in its content and to improve in its presentation.

Arthritis↗
PubMed1989

Targeting of proteins to the thylakoid lumen by the bipartite transit peptide of the 33 kd oxygen-evolving protein.

Various chimeric precursors and deletions of the 33 kd oxygen-evolving protein (OEE1) were constructed to study the mechanism by which chloroplast proteins are imported and targeted to the thylakoid lumen. The native OEE1 precursor was imported into isolated chloroplasts, processed and localized in the thylakoid lumen. Replacement of the OEE1 transit peptide with the transit peptide of the small subunit of ribulose-1,5-bisphosphate carboxylase, a stromal protein, resulted in redirection of mature OEE1 into the stromal compartment of the chloroplast. Utilizing chimeric transit peptides and block deletions we demonstrated that the 85 residue OEE1 transit peptide contains separate signal domains for importing and targeting the thylakoid lumen. The importing domain, which mediates translocation across the two membranes of the chloroplast envelope, is present in the N-terminal 58 amino acids. The thylakoid lumen targeting domain, which mediates translocation across the thylakoid membrane, is located within the C-terminal 27 residues of the OEE1 transit peptide. Chimeric precursors were constructed and used in in vitro import experiments to demonstrate that the OEE1 transit peptide is capable of importing and targeting foreign proteins to the thylakoid lumen.

Algal Proteins↗