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Gene mapping in chicken-Chinese hamster somatic cell hybrids. Serum albumin and phosphoglucomutase-2 structural genes on chicken chromosome 6.

Chicken phosphoglucomutase (PGM-2), serum albumin, vitamin D binding protein (Gc) and phosphoribosyl pyrophosphate amidotransferase (PPAT) structural genes have been mapped to chicken chromosome 6 using chicken-Chinese hamster somatic cell hybrids containing this chromosome as the only chicken genetic material. Chicken PGM-2 activity was detected in the hybrids using cellogel electrophoresis and a substrate, ribose-1-phosphate (R-1-P), that allows the detection of PGM-1 activity in mice and PGM-2 activity in humans. Chicken albumin sequences were detected in the hybrids with the use of a labelled chicken serum albumin cloned cDNA. Classical studies have shown linkage of the serum albumin and Gc genes, and the Gc gene also can be localized to chicken chromosome 6. The PPAT gene was localized to this chromosome in previous studies using these hybrids. A homologous linkage group has been identified in mammals and, therefore, a chromosomal linkage group containing at least four genes--Gc, serum albumin, PPAT, and PGM-2--has been conserved over a period of 300 million years, throughout both avian and mammalian evolution.

Amidophosphoribosyltransferase↗

Genetic predisposition and somatic diversification in tumor development and progression.

Studies on human cancer predisposition syndromes have contributed significantly to our understanding on tumor initiation and progression. Work performed on hereditary colon cancer has been particularly fruitful. Much of the molecular background of the various intestinal polyposis syndromes, such as familial adenomatous polyposis (FAP), juvenile polyposis, and Peutz-Jeghers syndrome, has been revealed, pinpointing several key cancer-associated genes. Studies on hereditary nonpolyposis colorectal cancer (HNPCC) have revealed a novel mechanism of tumorigenesis; genomic instability caused by defective DNA mismatch repair (MMR). Understanding the molecular background of these diseases helps us to understand tumor initiation in the affected individuals. Relatively little is known about the details of tumor progression in hereditary and sporadic neoplasia. Certain additional gene mutations can be associated with advancing stages of the disease, but the pace and tempo of the process have remained obscure. A high mutation rate in MMR-deficient tumors has provided a new approach in the analysis of human tumor dynamics. Microsatellite (MS) sequences are frequently mutated in MMR deficient tumors. The high mutation rate allows the use of microsatellite mutations as a tool for analyzing the past patterns of tumor progression. This approach is similar to the use of MS mutations in studying human evolution and migrations. Such tumor studies have revealed progression pathways that differ from the classic adenoma-cancer sequence. The reasons why and how molecular clocks may reveal something new about a well-studied problem are discussed.

Animals↗

An Eph receptor sperm-sensing control mechanism for oocyte meiotic maturation in Caenorhabditis elegans.

During sexual reproduction in most animals, oocytes arrest in meiotic prophase and resume meiosis (meiotic maturation) in response to sperm or somatic cell signals. Despite progress in delineating mitogen-activated protein kinase (MAPK) and CDK/cyclin activation pathways involved in meiotic maturation, it is less clear how these pathways are regulated at the cell surface. The Caenorhabditis elegans major sperm protein (MSP) signals oocytes, which are arrested in meiotic prophase, to resume meiosis and ovulate. We used DNA microarray data and an in situ binding assay to identify the VAB-1 Eph receptor protein-tyrosine kinase as an MSP receptor. We show that VAB-1 and a somatic gonadal sheath cell-dependent pathway, defined by the CEH-18 POU-class homeoprotein, negatively regulate meiotic maturation and MAPK activation. MSP antagonizes these inhibitory signaling circuits, in part by binding VAB-1 on oocytes and sheath cells. Our results define a sperm-sensing control mechanism that inhibits oocyte maturation, MAPK activation, and ovulation when sperm are unavailable for fertilization. MSP-domain proteins are found in diverse animal taxa, where they may regulate contact-dependent Eph receptor signaling pathways.

Animals↗

Genomes and form. The case for teleomorphic recursivity.

The genotype-phenotype (genome-form) distinction is considered by many to be fundamental to modern evolutionary thinking. Indeed, the premises that: DNA solely constitutes the genotype; that the phenotype is a transient product of the genotype, with the latter not only describing, but also implementing the construction of the former; and that the constructed materials and systems of the cell have no impact on the genotype, have become dogmas. Yet a vast body of data from molecular genetics reveals that cellular systems, directly and indirectly, alter the genome. Some of these data are reviewed. Proteins can influence mutations along the chromosomes, heritably modify the information content of DNA sequences, and, in some instances, reorganize the germline or somatic genome via DNA engineering pathways. These data suggest that the constructed (proteins, chromatin arrays, and metabolic pathways) has an important role in shaping the descriptor. Insofar as it is biochemically possible for states adopted by cellular structures to be stabilized and eventually memorized by engineering chromosomes, semantic closure can be transcended--meaning can be transferred from the domain of form to the genome, and this presumably ongoing process is termed teleomorphic recursivity. Throughout the paper, I implicitly argue that the genome-form partition is strictly a formal one, with no deeply material basis.

Biological Evolution↗

Evolutionary conservation of Ceratitis capitata transformer gene function.

Transformer functions as a binary switch gene in the sex determination and sexual differentiation of Drosophila melanogaster and Ceratitis capitata, two insect species that separated nearly 100 million years ago. The TRA protein is required for female differentiation of XX individuals, while XY individuals express smaller, presumably nonfunctional TRA peptides and consequently develop into adult males. In both species, tra confers female sexual identity through a well-conserved double-sex gene. However, unlike Drosophila tra, which is regulated by the upstream Sex-lethal gene, Ceratitis tra itself is likely to control a feedback loop that ensures the maintenance of the female sexual state. The putative CcTRA protein shares a very low degree of sequence identity with the TRA proteins from Drosophila species. However, in this study we show that a female-specific Ceratitis Cctra cDNA encoding the putative full-length CcTRA protein is able to support the female somatic and germline sexual differentiation of D. melanogaster XX; tra mutant adults. Although highly divergent, CcTRA can functionally substitute for DmTRA and induce the female-specific expression of both Dmdsx and Dmfru genes. These data demonstrate the unusual plasticity of the TRA protein that retains a conserved function despite the high evolutionary rate. We suggest that transformer plays an important role in providing a molecular basis for the variety of sex-determining systems seen among insects.

Animals↗

Purification and characterization of the histones associated with the macronucleus of Tetrahymena.

Histone fractions have been isolated from the macronucleus of Tetrahymena pyriformis. Five classes of macronuclear histone were purified, using a combination of gel exclusion and ion-exchange chromatography, and were examined with respect to their solubility, electrophoretic, chromatographic, and chemical properties. Tetrahymena H4 is very similar to vertebrate H4, except that it exhibits a larger number of acetylated subfractions. In contrast, the other Tetrahymena histones vary more extensively from their calf thymus counterparts. Tetrahymena H3 resembles calf thymus H3 in its solubility properties and is the only macronuclear histone containing cysteine. However, it differs from vertebrate H3 in composition and has a faster electrophoretic mobility on both urea-acrylamide and sodium dodecyl sulfate-acrylamide gel electrophoresis. Tetrahymena H3 also displays a level of acetylation higher than that reported for its vertebrate homologue. Approximately 45% of macronuclear H2B, which resembles calf thymus H2B in composition and solubility, is present in a (mono)acetylated form, not detected in vertebrate somatic H2B. H1, though similar to its calf thymus homologue in solubility, modification (by phosphorylation), and other properties, differs considerably in its content of basic, acidic, and hydrophobic amino acids. Tetrahymena does not contain a histone strictly homologous to H2A. Although macronuclear histone X resembles H2A in chromatographic and some solubility properties more like H2B than H2A. Fraction X is polymorphic in sodium dodecyl sulfate-acrylamide gels, migrating as two distinct molecular forms. While it is possible that one form is H2A-like and the other more H2B-like, the observation that both forms of X behave identically in solubility fractionation schemes makes this unlikely. Fraction X is both phosphorylated and acetylated which, in addition to two molecular forms, results in a characteristic heterogeneous pattern on urea-acrylamide gels. Characterization of the histone complement of this lower eucaryote should contribute to the understanding of the evolution and biological role of these basic proteins. Moreover, this description represents the most extensive analysis to date of the histones associated with an amitotic, genetically active nucleus. It will serve as a reference to which the histones of the morphologically distinct, mitotically dividing, and genetically inactive micronucleus of this organism can be compared.

Amino Acids↗

The Reed-Sternberg cell in classical Hodgkin's disease.

There has been substantial advances in our understanding of the nature of the Hodgkin/Reed-Sternberg (H/RS) cell in recent years. There is now compelling evidence that the H/RS cells in the vast majority of cases of classical Hodgkin's disease (CHD) are derived from the B-cell lineage and a major clonal population is present. The immunoglobulin heavy chain variable region gene generally has a high load of somatic mutations suggesting that the H/RS cells are derived from germinal center (GC) (GC) or post-GC cells. The cellular milieu in the tumour is largely determined by the cytokines and chemokines secreted by the H/RS cells and the surrounding reactive elements. The pattern of secretion is partially determined by signals transduced through direct surface interactions between H/RS cells and infiltrating T-cells. Immunosuppressive cytokines and cytokines that preferentially induce a TH2 type of immune response may be partially responsible for the escape of the H/RS cells from immune surveillance. Multiple genes that have been shown to be involved in neoplastic transformation have been studied in HD. The significance of the data generated has been difficult to interpret. Efforts have been made to study the global gene expression pattern of the H/RS cells. There are many difficulties inherent in this approach, but new insight into the pathogenesis and evolution of HD would be expected from the studies.

Clone Cells↗

Distribution of major mental disorders in an US metropolis.

This paper reviews the evolution of psychiatric nosologies in North America and the major epidemiological surveys of Mental Disorders culminating with the recently completed National Institute of Mental Health Epidemiologic Catchment Area project (NIMH-ECA). The NIMH-ECA examined the prevalence of diagnosable (DSM III) Mental disorders in 5 U.S. communities utilizing a highly structured diagnostic interview, the Diagnostic Interview Schedule (DIS). Data from the Los Angeles ECA, one of five study sites are presented with particular emphasis on cross-cultural comparison (Mexican Americans versus Non Hispanic Whites). Overall, there were only a few cross-cultural differences in prevalence of specific diagnoses. Mexico-born Mexican Americans showed a lower prevalence for most disorders examined than their U.S. born counterparts, and a subgroup of Mexican-American women (those over the age of 40) showed higher rates of phobic and dysthymic disorders as well as a greater number of functional somatic symptoms than other groups.

Acculturation↗

Differential induction of altered gene expression by carcinogens at mutant alleles of a Drosophila locus with a transposable element.

Alterations in gene expression by carcinogens were analyzed on three unstable alleles of the white (w+) locus of Drosophilia melanogaster: white-crimson (wc); white-ivory 16 (wi16); and white-unstable 11 (wu11). Two of these alleles (wi16 and wu11) were spontaneous mutant derivatives of wc, which is known to harbor a transposable element. The compounds studied were dimethylnitrosamine, 7,12-dimethylbenz(a)anthracene, and aflatoxin B1. These carcinogens were topically applied on the early larval stages, and the genetic effects assayed were the alterations in eye color either to wild-type (w+) or to other w mutants, initiated both somatically and germinally, as well as the simultaneously induced X-chromosome recessive mutations. The tested compounds influenced the different unstable w alleles in a highly selective manner, both as a function of the inducing agent and the organization of the genome in the target cells. The same treatments raised the somatic reversions to w+ above the corresponding controls for wc and wi16, but not for wu11, whereas the simultaneous induction of other w mutant phenotypes occurred appreciably only with wc. Furthermore, these treatments gave high and variable somatic reversions to w+ with wi16, whereas the simultaneously induced germinal events were uniformly very low. The frequencies of altered expression at the unstable test loci, whether in the soma or germ line, were quantitatively uncorrelated with the mutagenic effects of the treatments in terms of the yield of X-chromosome recessive mutations assayed in the progeny of males emerging from the same treated larvae. There was also an association between the time of the induction of these alterations by the tested carcinogens in the soma and the cellular stage in genomic differentiation. Reversions to w+ were induced preferentially after the onset of genetic determination, whereas changes to the w mutant phenotypes occurred predominantly during the predetermination phases. The genetic properties of transposable elements and the manner of their response to carcinogens supported the hypothesis that nonviral cancer might arise from molecular processes similar to those involved in the evolution of retroviruses.

9,10-Dimethyl-1,2-benzanthracene↗

[The clinicopsychological and therapeutic significance in the depression-pain relationship].

The frequency of depression-pain association, gives the authors the opportunity of evaluating the actual pattern of managing pain according to its sensory-discriminatory, affective-emotional, cognitive and behavioral features. The neurophysiologic, affective and psychologic factors generally correlate in the induction and evolution of pain, being dependent on the individual reactivity environmental and socio-cultural relations. The efficacy of antidepressive drugs in the therapy of pain, explained by their action on the serotoninergic systems, advocates the clinical relationship depression-pain, but also their analgesic properties independent from the thymoanaleptic effect. The results of the clinical essays the authors have carried on some antidepressants (Imipramine, Amitryptyline, Mianserine, Maprotyline) evidenced their effect on the various forms of manifestation and localizations of pain complains. The amelioration of pain, certified by the use in dynamics of Hamilton's depression scale, occurs earlier than the improvement of depressive symptoms, thus attesting the analgesic properties of the antidepressants. The preservation and merging of these effects during the investigation interval, at the same time with an improvement in the depressive symptoms support the clinical correlation depression-pain, emphasizing the complex character of the algopathic syndrome, both somatically and mentally.

Antidepressive Agents↗

Use of chromosome painting for detecting stable chromosome aberrations induced by melphalan in mice.

Chromosomal aberrations are a measure of genomic instability, which is known to play a key role in the initiation and promotion of carcinogenesis. Stable reciprocal translocations are of particular importance since they are often involved in neoplastic transformation and tumor cell clonal evolution. In this study, chromosome painting analysis was used to test for stable aberrations induced in the bone marrow of C57BL/6J and FVB mice exposed for 4 weeks to 2 or 4 mg/kg of melphalan (MLP), a chemotherapeutic agent with carcinogenic potential. To compare the chemical-induced damage in different tissues, chromosome aberrations were also analyzed by chromosome painting in the spleen of C57BL/6J mice. At the 2 mg/kg dose, MLP induced comparable levels of chromosome-type aberrations in bone marrow cells of both mouse strains and in splenocytes of C57BL/6J mice. At 4 mg/kg, no further increase in aberrations was detected in bone marrow, while a dose-effect relationship was found in spleen cells. This different response may result from a negative selection against highly damaged bone marrow cells during mitotic proliferation. The results indicate that chromosome painting is a useful tool for detecting stable chromosome aberrations in somatic cells exposed to MLP and possibly to other genotoxic chemical carcinogens.

Animals↗

Megabase inversions in the human genome as physiological events.

The genes of the immunoglobulin kappa light chains are assembled during B-cell differentiation by somatic recombination of one of the V kappa (variable) gene segments and the J kappa-C kappa (joining-constant) gene region. This seems to occur by deletion of the DNa between V kappa and J kappa-C kappa if they are arranged in germ-line DNA in the same transcriptional polarity or by inversion of a fragment containing the V kappa gene if the polarities are opposite. We have cloned 75 V kappa genes and pseudogenes of the human kappa locus and linked them in large contigs. There seem to be no more than 85 such genes, less than 50 of these being potentially functional. Thirty-eight of the cloned genes have the same transcriptional polarity as J kappa-C kappa and are part of the so-called J kappa proximal cluster; 35 genes in a distal cluster (the result of a duplication event in evolution) have a polarity that was suggested to be opposite to the one of J kappa-C kappa. We now show that the V kappa genes of the proximal cluster rearrange by a deletion mechanism whereas the others join J kappa-C kappa by inversion of megabase-sized DNA fragments.

Base Sequence↗

The testis-specific phosphoglycerate kinase gene pgk-2 is a recruited retroposon.

In both humans and mice, two genes encode phosphoglycerate kinase, a key enzyme in the glycolytic pathway. The pgk-1 gene is expressed in all somatic cells, is located on the X chromosome, and contains 10 introns. The pgk-2 gene is expressed only in sperm cells, is located on an autosome, and has no introns. The nucleotide sequence of the pgk-2 gene suggests that it arose from pgk-1 more than 100 million years ago by RNA-mediated gene duplication. The pgk-2 gene may, then, be a transcribed retroposon. Thus, gene duplication by retroposition may have been used as a mechanism for evolutionary diversification.

Amino Acid Sequence↗

The security circuit: a proposed construct for the central nervous system.

The theory of the Security Circuit offers a new conceptual framework for the numerous brain functions pertaining to survival. Many such activities are related to the coordination of the conventional physiological systems in the maintenance of homeostasis and the defense of the internal environment. This work, however, focuses on that aspect of brain function that makes possible man's interaction with external environment, thereby facilitating individual and group adaptation and survival. In our schema we greatly enlarge the conceptualization of the autonomic nervous system. We postulate the existence of a central mechanism pertaining to the security and survival function. In its action the complex physiological ANS substrate designated the Security Circuit, is likened to a whirlpool bath, in which balance is maintained with respect to electrically-charged particles rather than water. The use of the Jacuzzi (or whirlpool bath) format makes it possible to tie together the components of the triune brain (MacLean), which consists of R-complex, limbic system, and neocortex. The forebrain, in part, is viewed as the depository of biological symbolism for a huge number of elements, which vary with the individual. Among these are security and support figures, and others that make up meaningful relationships. These are seen as represented on posts, consisting of either individual, or else groupings, of neurons which are linked to the limbic system to trigger oft predictable patterns of behavior and/or emotional expression. The limbic system serves as the energizer in arousal-defense. It also serves to trigger instinctive and other psychomotor patterns in the pursuit of goals which have survival value, while simultaneously producing the chemistry behind emotions useful to man. Some of these psychomotor patterns (i.e., behavior) facilitate the provision of nutrients and warmth for the individual, and so ensure internal homeostasis, while others effectuate group action towards this end. The apparent neuroendocrinal sequence of events in many common environmental situations is discussed. Responses to a perceived threat are examined, noting both the reflex behavior patterns resulting from somatic and ANS discharge, and the associated emotional expression. The chemoelectrical workings of the limbic system keep the central mechanism in a state of balance, while neocortical centers of cognition translate the minute changes in the chemical mix into subjective emotional experience which contribute to the phenomenon of consciousness. The R-complex is seen as the physiological component of the unconscious brain regulating the internal vital functions. The task of the higher centers is not merely to inhibit impulsive (primitive) responses, but also has the following functions: (i) determine the more sophisticated, effective manner of dealing with perceived threats, and (ii) initiate and facilitate the pursuit of goals promoting survival and well-being for self and group. The human thrust to self-expression or self-actualization is seen as an outgrowth of this process. The theory suggests that intellectual and creative activity within a group is an extension in evolution of primal, survival functions. This thrust has resulted in the growth of culture and development of civilization. While the related neurophysiological activities enhance security and environmental adaptation for self and group, they simultaneously resolve heightened microelectrical tension within the underlying mechanism within the individual's neuroendocrinal complex. The brain, and autonomic and endocrine systems are seen as parts of the same physiological system which pertains to security, survival, and well-being. The concept is presented that the thrust to maintain microelectrical balance within the Security Circuit (a substrate of the CNS) has been the ever-present, ongoing driving force behind the evolution of the "higher," neocortical centers of consciousness during the psych

Adaptation, Physiological↗

The fine structure of the paralabial organelle in the rumen ciliate Ophryoscolex purkinjei Stein, 1858.

The paralabial organelle of the rumen ciliate Ophryoscolex purkinjei, located on the ventral side of the ciliophor, is a highly specialized part of the somatic cortex. It consists of alternating rows of short modified cilia and thin pellicular folds which form a ridge-like structure. The central "top kinety" is composed of monokinetids which bear cilia with 9 + 2 axonemes and 2 microns in length. The top kinety is accompanied by a comb-shaped fold on its distal side and by a broad wedge-shaped fold on its proximal side. To both sides there follow two or three lateral kineties made of dikinetids. The anterior kinetosome of each pair bears a clavate cilium, only 0.5-0.7 micron in length and with a 9 + 0 axoneme while the cilium of the posterior kinetosome is even shorter. Lateral folds with numerous microtubules cover these lateral kineties and rows of barren basal bodies. The fine structure of this supposed sensory organelle show a basic pattern in four other ophryoscolecids, and its increasing complexity parallels the suggested phylogenetic line of evolution of these ciliates.

Animals↗

[Postoperative disease: evolution of the concept].

Leriche's La Maladie post-opératoire was described in 1934 as a specific and general reaction to surgery whose systemic symptoms could'nt be understood by the clinical appraisal alone. A laboratory analysis would be necessary. According to Leriche the syndrome could be observed also on other non-surgical trauma. Leriche's concept was ignored by the anglo-saxonic literature but a new scientific approach to the same problem came from Harvard. Walter Cannon with his concept of homeostasis and Henderson, Gamble, Peters and Van Slyke with their definition of the chemical anatomy of the organic fluids and their quantitative analysis, opened the way to Francis Moore's concept of surgery and trauma as metabolic problems. This new biological basis, and the broad enlargement of its spectrum to the whole body, gave a new scope to the surgical practice. Surgery must now be considered as an integrated process, a succession of phenomena defined as pre-operative, per-operative and post-operative representing, nevertheless, a true continuity. To its understanding the post-operative phase cannot be separated from the other phases. La maladie post-opératoire cannot be defined as an unity: there are several post-operative diseases. But the surgical patient must be considered always in the totality of his elements: the somatic or anatomical, the metabolic or physiological and the psychic, forming a complete unity. A global vision versus the old local vision of surgery. This enlarged concept of surgery enables the surgeon to have an intellectual approach similar to that of the physiologist.

General Surgery↗

The autonomic nervous system, molder and integrator of function. Review of a concept.

This paper treats a number of topics relative to functions of the autonomic nervous system: its role in the sympathies and emotional inter-reactions essential to society and common endeavor; the history and evolution of our knowledge of the structure, composition and function of this system; the recent concurrent genesis of concepts of the roles this system plays. Among the most recently developed ideas of autonomic system function is that of its integrating role and that of its molding role in determining the color and intensities of behavioral responses. These latter concepts are supported by recent discoveries of the role played in sensory reception, in several disease states, in control of the neuroendocrine and endocrine systems, in modulation of cardiovascular function, in regulation of energy release and use, and, finally, in conditioned behavior. It appears that there is considerable plasticity and possibility of drastically modifying cell of this system which normally would have functioned in a quite different way. Modern methods of anatomical analysis have shown that the central representation of the autonomic outflow is not as simplistically and independently organized as often visualized. Furthermore the same centers which control somatic responses also affect autonomic system activity. There is only one nervous system and the autonomic complex is an integral part thereof, participating in all behavior. It is, however, specially concerned with the emotional component, reactions to real or anticipated emergencies, control of the viscera and maintenance of homeostasis. In addition to integrating the activity of body parts it has a modulatory effect on all functions.

Autonomic Nervous System↗

Genetic structure and chromosomal mapping of MyD88.

The myeloid differentiation (MyD) marker MyD88 was initially characterized as a primary response gene, upregulated in mouse M1 myeloleukemic cells in response to differentiation induced by interleukin-6. Subsequent analysis revealed that MyD88 possesses a unique modular structure, which consists of an N-terminal "death domain," similar to the intracellular segments of TNF receptor 1 and Fas, and a C-terminal region related to the cytoplasmic domains of the Drosophila morphogen Toll and vertebrate interleukin-1 receptors. In this report we describe the cloning and gene structure of mouse MyD88. The complete coding sequence of mouse MyD88 spans five exons, with the first exon encoding the complete death domain. Zooblot analysis revealed that MyD88 is an evolutionarily conserved gene. MyD88 was localized to the distal region of mouse chromosome 9 by interspecific backcross mapping. The human homolog (hMyD88) was mapped to chromosome 3p22-p21.3 by PCR analysis of a human chromosome 3 somatic cell hybrid mapping panel. Northern blot analysis revealed widespread expression of MyD88 in many adult mouse tissues, and RT-PCR studies detected MyD88 mRNA in T and B cell lines and differentiating embryonic stem cells. The broad expression pattern demonstrates that mouse MyD88 expression is not restricted to cells of myeloid lineage as was originally believed.

Adaptor Proteins, Signal Transducing↗