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PubMed1986

[Theory of the continuity of germ plasma according to the findings of modern biology].

The main principles on the theory of germ plasma by A. Weismann are briefly presented; a number of his genetic-embryological hypotheses proved to be prophetic. Modern notions on the germ plasma are critically discussed, as well as the resulting from them the conception on continuity of totipotent cells (the source of germ cells) in the line of generations, that is historically connected with M. Nussbaum--A. Weismann's notions on continuity of the embryonic pathway. The term totipotency is sometimes used inaccurately; it means ability to formation of a whole organism. In Metazoa zygota and isolated blastomeres, at a regulative type of development, and groups of somatic cells or fragments of the organism, at an asexual reproduction and somatic embryogenesis, possess this ability. In ontogenesis totipotency is lost both by the somatic and by the germ cells because of their specialization and is recreated with the beginning of every ontogenesis when zygota is formed. The germ cells are always a product of the organism--unicellular or multicellular, and their specialization in all its manifestations is the result of integrative influences of the organism as a whole of them. Certain reasons are presented for supporting ideas on germ cells as one of the lines of cell differentiation. The main, if not the only contradiction in the problem concerning relation of the germ and somatic cells is, at the present time, the thesis on continuity of totipotent cells in the line of generations.

Biological Evolution↗
PubMed1995

Clonal evolution of an immunoblastic type non-Hodgkin's lymphoma with der(6)t(1;6)(q11;p11) as its primary cytogenetic abnormality.

Recurrent pleural effusions from a 45-year-old man who was diagnosed as having non-Hodgkin's lymphoma of immunoblastic type were studied cytogenetically. The majority of the metaphases were tetraploid, but there were also lymphoma cells observed with pseudodiploid chromosome constitutions. Cytogenetic analysis by G-banding revealed the existence of at least two cell populations. The karyotype of the minor pseudodiploid clone, which exhibited partial trisomy of 1q11qter and monosomy of 6p11pter as sole abnormalities, was 46,XY,der(6)t(1;6)(q11;p11). The karyotype of the major clone was 92,XXYY,-1,der(6)t(1;6)(q11;p11)x2, +9. The ancestral diploid clone, carrier of the balanced translocation involving chromosomes 1 and 6, was not observed even in the first pleural effusion harvest. The high proportion of tetraploid cells in the recurrent effusions was an indication that these cells were favorably selected in the environment of the somatic cavity. Our cytogenetic findings suggest that partial trisomy of 1q may be a crucial secondary chromosomal abnormality in highly malignant non-Hodgkin's lymphoma. This genetic imbalance was predetermined from the primary abnormality and may be responsible for further tumor progression, as suggested from the clonal evolution in this particular case and, therefore, may be associated with the aggressive biologic behavior of malignant cells.

Chromosome Aberrations↗
PubMed1987

Isozymes as bioprobes for genetic analysis of nonhuman primates.

The identification and the utilization of genetically determined electrophoretic differences of enzymes between the individuals of species as well as between cell lines have played an important role in the advancement of mammalian genetics during the past quarter of a century. In an explicit search we found a number of red cell enzyme polymorphisms in each of the following four species: chimpanzees, orang utans, rhesus monkeys and brown capuchins. Allelic distribution patterns among populations have indicated trends of subspeciation among chimpanzees and orang utans due to geographic barriers leading to reproductive isolation. Investigations of quantitative levels of red cell glucose-6-phosphate dehydrogenase have suggested that relative activity profiles of certain enzymes among species may be helpful in studies of the evolution of physiological traits and their biological significance during speciation. A large number of biochemical genetic markers in primate-rodent (i.e., chimpanzee-, gorilla-, orang utan-, rhesus monkey- and African green monkey-Chinese hamster) somatic cell hybrids have been identified and are useful for primate genetic analysis. Some of the biologically relevant observations on the enzyme markers in the above mentioned primate species are discussed.

Animals↗
PubMed1986

Cytogenetic "rogue" cells: what is their frequency, origin, and evolutionary significance?

Among 102,170 cultured lymphocytes obtained from 9818 individuals from Hiroshima, Japan, aged 9 to 37 years and scored for chromosomal abnormalities, 24 cells that exhibited an extreme degree of damage were encountered. The damage consists of multiple dicentric and even tricentric chromosomes, as well as numerous fragments, many with the appearance of "double minutes." The occurrence of these cells was not correlated with parental exposure to the atomic bomb, age, sex, year, or season. They were nonrandomly distributed by individual. Such cells were originally described in South American Indians and have also been recorded in inhabitants of the United States and the United Kingdom; this appears to be a world-wide phenomenon. Their cause remains unknown, and it is not known whether they occur in other somatic and germ-line cells. Should the latter be the case and should the least damaged of these cells occasionally successfully complete mitosis and meiosis, the possible role of such cells in oncogenesis and evolution must be considered.

Adolescent↗
PubMed2006

Novel analysis of clonal diversification in blood B cell and bone marrow plasma cell clones in immunoglobulin light chain amyloidosis.

Immunoglobulin light chain amyloidosis (AL) is characterized by a limited clonal expansion of plasma cells and amyloid formation. Here, we report restriction in the diversity of VL gene usage with a dominance of clonally related B cells in the peripheral blood (PB) isotype-specific repertoire of AL patients. A rigorous quantification of lineage trees reveals presence of intraclonal variations in the PB clones compared to the bone marrow (BM) clones, which suggests a common precursor that is still subject to somatic mutation. When compared to normal BM and PB B cells, AL clones showed significant but incomplete impairment of antigenic selection, which could not be detected by conventional R and S mutation analysis. Therefore, graphical analysis of B cell lineage trees and mathematical quantification of tree properties provide novel insights into the process of B cell clonal evolution in AL.

Algorithms↗
PubMed1980

Amino acid diversity of immunoglobulins as a product of molecular evolution.

Based on population genetics theory of the evolution of multigene families, the sequence variability of the variable regions of immunoglobulins compiled by Kabat et al. (1976) has been analysed. An amino acid identity coefficient either within or between species is calculated separately for both the hypervariable and the framework regions. Under the somatic mutation hypothesis, the somatic component of amino acid diversity is in addition to the germ line component and should contribute an amount of change between the hypervariable and framework regions that is independent of the time since the divergence of any two immunoglobulin gene families. The relationship between the identity coefficient of the hypervariable region and that of the framework region is shown to be not in accord with such prediction. The result indicates that the rate of evolutionary accumulation of amino acid replacements in the hypervariable region is roughly three times more rapid than in the framework region and the hypervariability within a species is a necessary consequence of the high evolutionary rate.

Amino Acid Sequence↗
PubMed2006

Reproduction and longevity: secrets revealed by C. elegans.

What is the relationship between reproduction and longevity? Evolutionary biology suggests that reproduction exacts a cost in somatic maintenance, a cost that reduces longevity. The frequent occurrence of this tradeoff between life span and fecundity, both due to experimental manipulations as well as natural variation, suggest that the mechanism might be conserved during evolution. Until recently, little was known about the mechanistic details of how reproduction might regulate life span. Here we discuss recent advances in our understanding of the regulation of life span by reproductive signaling, focusing on studies using Caenorhabditis elegans.

Aging↗
PubMed1998

Heterogeneity of microsatellite mutations within and between loci, and implications for human demographic histories.

Microsatellites have been widely used to reconstruct human evolution. However, the efficient use of these markers relies on information regarding the process producing the observed variation. Here, we present a novel approach to the locus-by-locus characterization of this process. By analyzing somatic mutations in cancer patients, we estimated the distributions of mutation size for each of 20 loci. The same loci were then typed in three ethnically diverse population samples. The generalized stepwise mutation model was used to test the predicted relationship between population and mutation parameters under two demographic scenarios: constant population size and rapid expansion. The agreement between the observed and expected relationship between population and mutation parameters, even when the latter are estimated in cancer patients, confirms that somatic mutations may be useful for investigating the process underlying population variation. Estimated distributions of mutation size differ substantially amongst loci, and mutations of more than one repeat unit are common. A new statistic, the normalized population variance, is introduced for multilocus estimation of demographic parameters, and for testing demographic scenarios. The observed population variation is not consistent with a constant population size. Time estimates of the putative population expansion are in agreement with those obtained by other methods.

Adenocarcinoma↗
PubMed2003

[Clinical case of the month. Chronic eosinophilic pneumonia].

We report the case of a 32-year old man who had a feverish pneumopathy with coughing. An idiopathic eosinophilic pneumonia was soon disclosed; the evolution was rapidly favourable under systemic corticotherapy, but marked by a cortico-dependence in the long term. The follow-up of the relapses, when corticotherapy was stopped, showed a perfect correlation between reappearance of somatic plaints and eosinophilic blood levels.

Adult↗
PubMed1998

V(H) repertoire of a marsupial (Monodelphis domestica).

When contrasted with information available for placental mammals, very little is known about the development of immunocompetence in marsupials. Marsupials, however, provide interesting immunology problems, since most appear to be born at a stage of development much less mature than that of placental mammals. To further understand the marsupial immune system, the Ig repertoire of the short-tailed opossum, Monodelphis domestica, was characterized. The majority of the V(H) clones were isolated in an unbiased manner by screening a spleen cDNA phage library, using C region probes, or anchored PCR, using C region-specific primers paired with vector specific primers. Analysis of 54 unique V(H) sequences from this marsupial revealed the presence of two V(H) families in the expressed Ig repertoire. The larger family, which contributed the majority of the clones identified, appears to be derived from 10 to 12 germline V(H) segments. The second family of clones is derived from a single germline V(H). Both V(H) families are related to the group III sequences described in other vertebrates. Unusual codon bias differences between the two families may result in very different patterns of somatic mutation within the opossum Ig repertoire.

Amino Acid Sequence↗
PubMed2006

Clonal origin and evolution of a transmissible cancer.

The transmissible agent causing canine transmissible venereal tumor (CTVT) is thought to be the tumor cell itself. To test this hypothesis, we analyzed genetic markers including major histocompatibility (MHC) genes, microsatellites, and mitochondrial DNA (mtDNA) in naturally occurring tumors and matched blood samples. In each case, the tumor is genetically distinct from its host. Moreover, tumors collected from 40 dogs in 5 continents are derived from a single neoplastic clone that has diverged into two subclades. Phylogenetic analyses indicate that CTVT most likely originated from a wolf or an East Asian breed of dog between 200 and 2500 years ago. Although CTVT is highly aneuploid, it has a remarkably stable genotype. During progressive growth, CTVT downmodulates MHC antigen expression. Our findings have implications for understanding genome instability in cancer, natural transplantation of allografts, and the capacity of a somatic cell to evolve into a transmissible parasite.

Aneuploidy↗
PubMed1995

The 'cancell' theory of carcinogenesis: re-evolution of an ancient, holistic neoplastic unicellular concept of cancer.

The 'cancell' theory of carcinogenesis is based on four assumptions: 1. that there is early evolvement of neoplastic potentials in certain unicellular eukaryotes (so-called cancell lines) by adaptive response to the various carcinogens of the primitive Earth. The process that led to the neoplastic potential is called 'early carcinogenesis'; 2. that there is transition of cancell lines to multicellular forms; 3. that there is uptake of the basic genetics and epigenetics of the cancell concept into the genomic program of multicellular entities and their conservation even in human cells, and 4. the re-emergence of the ancient cancell concept in human somatic cells in a process called 'late carcinogenesis'. According to this theory, both processes of carcinogenesis, the early one and the late one, are thought to be the result of a physiological adaptive response to the various genotoxic and nongenotoxic carcinogens.

Animals↗
PubMedDate not supplied

Depression and social change. From transcultural psychiatry to a constructivist model.

Based on the findings of previous studies carried out by our group, which will be briefly summarised, the present paper puts forward several hypotheses to account for the evolution of depressive symptoms and the possible increase observed in risk of depression subsequent to social changes. The particular mood disorders presented by Senegalese emigrants and several protective factors which appear to determine a low risk in these populations, such as a strong social support, will be examined. Based on a previous investigation carried out by our group, which seems to indicate the presence of depressive pictures among poorly westernised populations such as the Peul nomads or Dogon farmers from the Sub-Saharian regions, the hypothesis that "westernalisation" (considered as the loss at an individual level of traditional ways of life, working habits, cultural patterns and languages in favour of different attitudes influenced by western culture) may represent a risk factor for depressive illness, in its clinical expressions commonly observed in western contexts, has been considered. In these populations, with the exception of educated individuals, the albeit rare depressive symptoms appear to be secondary to serious somatic disorders. Research performed identified two well-defined means of clinical expression, which has been termed, respectively, "western style" or "guilty" and "traditional" or "dislocation from the group". Further studies carried out in rapidly changing areas seem to indicate how environmental factors are able to influence the evolution of depressive symptoms from the first form to the latter and to modify the threshold of onset of emotive, behavioural and depressive patterns. It has been hypothesised that rapid changes in the social organisation tend to exacerbate attitudes of "compulsive hyper-responsibilisation", a cognitive set of basic assumptions which may be considered at the same time both as a product of "westernalization" at an individual level and a risk factor for depression. Individuals who possess these basic characteristics, subsequent to the opportunities afforded by the social changes, tend to develop new complex systems of interpreting reality, causality, controlling of events and ways of expressing emotions. Accordingly, we herewith propose a reviewal of the entire threshold concept and provide a means of interpreting the transformation in depressive phenomena in view of the fact that, although the new levels of knowledge and learning better equip subjects to face the new situations, they also render them more vulnerable to depression.

Adult↗
PubMed1993

Evolution of protamine P1 genes in primates.

Protamine P1 genes have been sequenced by PCR amplification and direct DNA sequencing from 9 primates representing 5 major families, Cebidae (new world monkeys), Cercopithecidae (old world monkeys), Hylobatidae (gibbons), Pongidae (gorilla, orangutan, and chimpanzee), and Hominidae (human). In this recently diverged group of primates these genes are clearly orthologous but very variable, both at the DNA level and in their expressed amino acid sequences. The rate of variation amongst the protamine P1s indicates that they are amongst the most rapidly diverging polypeptides studied. However, some regions are conserved both in primates and generally in other placental mammals. These are the 13 N-terminal residues (including a region of alternating serine and arginine residues (the motif SRSR, res. 10-13) susceptible to Ser phosphorylation), a tract of six Arg residues (res. 24-29) in the center of the molecule, and a six-residue region (RCCRRR, res. 39-44), consisting of a pair of cysteines flanked by arginines. Detailed consideration of nearest-neighbor matrices and trees based on maximum parsimony indicates that P1 genes from humans, gorillas, and chimpanzees are very similar. The amino acid and nucleotide differences between humans and gorillas are fewer than those between humans and chimpanzees. This finding is at variance with data from DNA-DNA hybridization and extensive globin and mitochondrial DNA sequences which place human and chimpanzee as closest relatives in the super family, Hominoidea. This may be related to the fact that protamine P1s are expressed in germ line rather than somatic cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1998

Clonal overexpression of metallothionein is induced by somatic mutation in morphologically normal colonic mucosa.

Metallothionein (MT) overexpression occurs frequently in human tumours but the underlying mechanism is unknown. Morphologically normal-appearing mucosa from human colorectal carcinoma resection specimens and of the colons of ageing laboratory mice contains scattered single crypts whose cells show uniformly increased MT immunostaining, suggesting that MT overexpression arises directly from random crypt stem cell somatic mutation, followed by colonization of the clonal unit by the mutated progeny. This hypothesis has now been tested by quantifying the frequency of immunocytochemically detectable monocryptal colorectal MT overexpression, 5 and 30 days after injection of 8-week-old mice with a single dose of the mutagen dimethylhydrazine (DMH, 30 mg/kg subcutaneous). Otherwise normal-appearing MT-positive crypts were recorded as either wholly or partially involved by the overexpressing phenotype. Five days after DMH injection, the median frequency of partially involved MT-positive crypts was 11.7 x 10(-4), declining significantly to 1.8 x 10(-4) at 30 days (Mann-Whitney U, P < 0.01). In contrast, the median frequency of wholly involved crypts was 0.2 x 10(-4) at 5 days, increasing significantly (P < 0.005) to 12.9 x 10(-4) at 30 days. The frequency of MT-positive crypts and the time course of evolution of partially involved to wholly involved forms were similar to those described for mutation-induced crypt-restricted loss of glucose-6-phosphate dehydrogenase activity in mice treated with an identical DMH regimen. The findings indicate that cellular MT overexpression can occur as a direct consequence of somatic mutation, either cis-activating mutation(s) of the MT gene itself, or trans-activating mutation(s) of other genes involved in controlling MT expression. This is likely to be an important mechanism underlying MT overexpression in neoplasia. Such mutation-induced aberrant MT expression may be involved in the acquisition of selective cellular growth of survival advantage during tumour progression.

1,2-Dimethylhydrazine↗
PubMed1983

Utilization of Chinese hamster cells in vitro and in vivo in genetic toxicology: a multiphasic approach.

An approach often used to study genetic risk is comparative mutagenesis in different organisms. We have begun the development and validation of a multiphasic genetic toxicity system using the Chinese hamster and its somatic cells to measure mutational events in the same (or similar) gene, the same chromosome derived from the same animal (Fig. 1). This system will eliminate much of the uncertainty generated when different mutational events in such evolutionally divergent organisms as bacteria, insects, and mammals are compared. Using CHO cells we have defined an assay, CHO/HGPRT, to determine mutation at the hgprt locus. Coupled with S9 metabolic activation system, the CHO/HGPRT assay can quantify gene mutation and cytotoxicity induced by various classes of chemicals, physical agents, and the combination thereof. The quantitative nature of this assay permits elucidation of the structure-activity relationship for a given class of direct-acting agents. By incorporating the cytogenetics of CHO cells into this assay we can simultaneously measure induced chromosome aberrations and SCE. Using the stable CHO/human hybrid cell line AL-J1 measurement of chromosome deletion and/loss can be also performed. In order to further expand the usefulness of this genetic toxicity system to the molecular and whole animal levels we have begun development and validation of two additional systems. To study the molecular events which may result in mutation we are developing a CHOpSVgpt system. A Chinese hamster system with treatment in vivo is being developed to study mutation at the hgprt locus, chromosome aberration, and SCE in spleen cells in vitro. The use of this multiphasic genetic toxicity system at the cellular, molecular, and animal levels may soon provide reliable and rapid identification of suspected environmental mutagens.

Alkylating Agents↗
PubMed1989

Expression of DNA binding proteins in carrot somatic embryos that specifically interact with a cis regulatory element of the French bean phaseolin gene.

Nuclear proteins from bean (Phaseolus vulgarus) embryos bind specifically to a 55 bp DNA sequence located upstream of the seed storage protein gene phaseolin. This sequence is capable of elevating gene expression in transgenic tobacco plants by as much as 150-fold when fused to a chimeric beta-glucuronidase reporter gene. Results presented in this paper demonstrate that nuclear extracts from carrot embryos bind to a phaseolin DNA sequence that includes a phaseolin activator sequence. This specific DNA binding activity is modulated during somatic embryogenesis. Two separable protein species react specifically with the labeled phaseolin DNA fragment (58.0 and 51.7 kDa). These results suggest that the cis- and trans-acting elements controlling gene expression have been highly conserved during evolution.

DNA↗
PubMed2006

Strategy for affinity maturation of an antibody with high evolvability to (4-hydroxy-3-nitrophenyl) acetyl hapten.

In order to quantitate the contribution of amino acid replacements to an increase in affinity during affinity maturation, we measured thermodynamic parameters of the antigen-antibody interaction for a group of anti-(4-hydroxy-3-nitrophenyl) acetyl monoclonal antibodies whose differences in amino acid sequences had arisen only from somatic hypermutation. We prepared a common ancestor and hypothetical intermediate clones that might occur on the affinity maturation pathway, by employing site-directed mutagenesis. Isothermal calorimetric titration of the antigen-antibody reaction revealed that antibody evolution proceeds in two steps. The first step is driven by a decrease in enthalpy, in which two amino acid replacements in the VL region play an essential role. Further accumulation of amino acid replacements in VH and VL regions during the second step induce a progressive increase in affinity, which is driven by an increase in entropy, which has a cooperative mutational effect.

Amino Acid Sequence↗