bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytogenetics of Werner’s syndrome cultured skin fibroblasts: variegated translocation mosaicism
Authors: Salk D. , Au K. , Hoehn H. , Martin G.M.
Published: May 2008

Skin fibroblast-like (FL) cells from patients with Werner’s syndrome (adult progeria) regularly demonstrate frequent pseudodiploidy involving variable structural rearrangements that are clonal: variegated translocation mosaicism (VTM). Ninety-two percent of 1,538 metaphases from 29 independent strains derived from five patients with Werner’s syndrome demonstrated this cytogenetic abnormality. In contrast, only eight (8.4%) of 95 non-Werner’s syndrome FL cell cultures demonstrated VTM: seven with low-grade VTM (approximately 5% of 300 metaphases), and one with VTM affecting 90–100% of metaphases. Unlike the cytogenetic abnormalities observed in the terminal stages of normal FL cell cultures, VTM occurs throughout the entire lifespan of Werner’s syndrome cultures. Ten of the identifiable break points in 1,005 banded metaphases accounted for 27% of all definable rearrangements. Baseline sister chromatid exchanges were not increased. Co-cultivation of Werner’s syndrome and normal strains did not induce VTM in the normal strain. The relationship between VTM and the reduced growth potential of Werner’s syndrome FL cells is not yet understood, nor is the relationship between these in vitro abnormalities and the presumptive single gene defect that causes the progeroid clinical manifestations of Werner’s syndrome.
Evidence of clonal attenuation, clonal succession, and clonal expansion in mass cultures of aging Werner’s syndrome skin fibroblasts
Authors: Salk D. , Au K. , Hoehn H. , Stenchever M.R. , Martin G.M.
Published: May 2008

Skin fibroblast-like (FL) cells from patients with Werner’s syndrome (adult progeria) demonstrate multiple, stable, structural chromosome rearrangements (variegated translocation mosaicism) which can be used to identify cytogenetically marked clones of cells within a mass culture. We have cytogenetically followed eight FL cell strains (from two patients) throughout their entire in vitro replicative lifespans, and we show a correlation between the expansion and attenuation of individual clones and the growth of the mass cultures. One strain, which was aged several times, demonstrated a generally reproducible pattern of clonal succession but, surprisingly, also demonstrated, in two parallel derivative cultures, the late emergence of two relatively rapidly growing clones that had not been observed in the parental culture. These observations suggest that clonal succession and clonal attenuation occur in mass cultures, as had been predicted on the basis of dilute-plating cloning experiments. Our results may have implications for models of in vitro cellular senescence. In addition, there are interesting parallels with the tissue hyperplasia associated with in vivo aging, and this observation is compatible with the suggestion that skin FL cells in vitro provide a model for hyperplasia in vivo.
Silver-staining patterns of mammalian epididymal spermatozoa
Authors: Elder F.F.B. , Hsu T.C.
Published: May 2008

Epididymal spermatozoa from 12 species of mammals were stained using silver nitrate and examined with the light microscope. Silver nitrate differentiates many of the gross morphological features of spermatozoa, including the acrosome, subacrosomal region, perforatorium, postacrosomal sheath, neck, dense outer fibers of the core of the midpiece, annulus, principal piece, and end piece. Silver-staining patterns of spermatozoa reveal both species-specific and strain-specific differences, particularly of the sperm head. The biochemical basis of silver staining may be due in part to the presence of sulfhydryl- and disulfide-rich proteins; however, it cannot be explained entirely by the presence of these moieties. The detail obtained using silver nitrate staining, coupled with the ease and rapidity of the procedure, should be useful to workers in many areas of biological and medical research.
The effects of distamycin A on gorilla-, chimpanzee- and orangutan lymphocyte cultures
Authors: Schmid M. , Poppen A. , Engel W.
Published: May 2008

Lymphocyte cultures from the gorilla, chimpanzee, and orangutan were treated with the oligopeptide antibiotic distamycin A. This AT-specific DNA-ligand induces a distinct undercondensation in the quinacrine-bright heterochromatin of the gorilla and chimpanzee. This is also the case in human lymphocyte cultures. Distamycin A further causes an undercondensation in the nonheterochromatic bands 17q21 of the gorilla and 16q22 of man. No visible distamycin A-sensitive chromosome regions were determined in the orangutan. The in vitro treatment with distamycin A preserves the somatic pairings between the quinacrine-bright heterochromatic regions existing in the interphase nucleus until the succeeding metaphase stage. The phylogenetic origin of the quinacrine-bright and distamycin A-sensitive heterochromatin in the ancestor of man, the gorilla, and the chimpanzee is discussed.
The ancestral karyotype of platyrrhine monkeys
Authors: Dutrillaux B. , Couturier J.
Published: May 2008

The karyotypes of three platyrrhine monkeys (Callithrix jacchus, Saimiri sciureus, Aotus trivirgatus) were studied using a high resolution banding technique. Their chromosomes were compared with those of man and of Lagothrix lagotricha and Cebus capucinus, previously analysed. Based on the numerous banding homoeologies, a reconstruction of the karyotype of their common ancestor is proposed.
Skin fibroblast cultures derived from members of the Baltimore Longitudinal Study: a new resource for studies of cellular aging
Authors: Schneider E.L. , Monticone R. , Smith J. , Braunschweiger K. , Roberts T.
Published: May 2008

Approximately 100 human fibroblast-like cell lines derived from the upper arms of members of the Baltimore Longitudinal Study have been deposited in the Aging Cell Bank at the Institute for Medical Research, Camden, N.J. These cell lines were derived from individuals ranging from 29 to 96 years in age. The in vitro lifespan of each culture has been estimated by the distribution of colony sizes. The availability of cell lines of known proliferative potential from donors of various ages should provide an important new resource for cellular aging studies.
Delineation of 13q—deletion by replication banding in retinoblastoma
Authors: Camargo M. , Johnson M.P. , Cervenka J.
Published: May 2008

High-resolution replication banding was performed to (1) delineate at the prometaphase level small interstitial deletions of chromosome 13 in two unrelated patients with retinoblastoma (Rb) and (2) study the influence of these deletions in the replication autonomy of the regions involved. The present study indicates that, in spite of the fact that break points separate (split) bands ql4 and q21 in different segments, these deletions do not produce a position effect or alteration in the replication behavior of the abnormal chromosome 13’s. Each segment in the deleted chromosomes replicates with a chronology and pattern identical to the normal homolog’s. The present data also indicate that metaphase bands are not only autonomous foci of replication but that they can be further divided into subunits of replication which correspond to sub-bands observed in more elongated prometaphase chromosomes. Our results strongly suggest that prometaphase sub-bands represent units of chromatid organization and replication.
Chromosomal variation and constitutive heterochromatin in three porpoise species (genus Stenella)
Authors: Stock A.D.
Published: May 2008

Chromosomes from cultured fibroblasts of two Pacific porpoise species, Stenella attenuata and S. longirostris and one Atlantic species, S. dubia, were compared to test the feasibility of using variation in constitutive heterochromatin and other chromosomal characteristics for analyses of population relationships and defining stocks of endangered porpoises. The G-band karyotypes of the three species were identical except for minor band differences resulting from heterochromatin variation. The nucleolar organizer regions (NORs) were located on the same two pairs of acrocentric chromosomes in all three species, although individual variation occurred in the number of active NORs present. Differences in the distribution and amount of C-band heterochromatin were observed between the three species. Stenella attenuata and S. dubia were very similar in C-band pattern, while S. longirostris was distinctly different. Conspicuous heteromorphism between the C-heterochromatin of the homologs of several pairs of chromosomes was noted in all individuals examined. In addition, variation in the amount of heterochromatin was observed between the four S. attenuata individuals studied. Of the chromosomal characteristics studied, only C-heterochromatin variation holds promise for distinguishing interspecific populations of porpoises. The final decision regarding the feasibility of using C-band heterochromatin to distinguish interspecific populations of porpoises must await comparison of morphologically differing populations within what is currently regarded as a single species.
High-resolution bands in human fibroblast chromosomes induced by actinomycin D
Authors: Yu R.L. , Aronson M.M. , Nichols W.W.
Published: May 2008

High-resolution Giemsa-trypsin bands can be induced in the chromosomes of human skin fíbroblast cultures exposed to actinomycin D (final concentration, 2 µg/ml) before harvest.
Sex chromosomes of the Asian black pond turtle, Siebenrockiella crassicollis (Testudines: Emydidae)
Authors: Carr J.L. , Bickham J.W.
Published: May 2008

A heteromorphism in a pair of macrochromosomes in male Siebenrockiella crassicollis is interpreted as an XX/XY sex determining system. The heteromorphism involves a difference in centromere position and amount and distribution of heterochromatin. The only other sex chromosome system known in turtles is found in the kinosternid genus Staurotypus and is also an XX/XY system, but it involves a different chromosome pair and different chromosomal rearrangements. These two systems have independently arisen within the suborder Cryptodira and share no common ancestry. The sex chromosome system in Siebenrockiella represents a relatively early stage of differentiation. It differs from the hypothesized steps of differentiation in having a heterochromatically derived X.
Chromosomal radiation sensitivity in ataxia telangiectasia long-term lymphoblastoid cell lines
Authors: Littlefield L.G. , Colyer S.P. , Joiner E.E. , DuFrain R.J. , Frome E. , Cohen M.M.
Published: May 2008

Elevated frequencies of spontaneous chromosome breakage and hypersensitivity to radiation induced chromosome damage are characteristic findings in cultured lymphocytes and skin fibroblasts of patients with ataxia telangiectasia (AT). To determine whether long-term AT lymphoblastoid cells (B-lymphocytes) which do not express spontaneous chromosomal instability, exhibit increased chromosomal radiation sensitivity, four AT lymphoblastoid cell lines were exposed to various doses of 250 kVp X-rays during G2. At doses of 25 and 50 rad, the AT cells exhibited a 2–3 fold increase in radiation damage relative to that observed in B-cell lines or PHA stimulated lymphocytes from normal donors, while at 100 rad, the AT cells demonstrated approximately 1.5 times more lesions. These findings suggest that the genetic (or other) factors responsible for increased chromosomal radiation sensitivity in AT lymphocytes and fibroblasts also operate in long-term lymphoblastoid AT cells.
Mapping of polypeptide genes by two-dimensional gel electrophoresis of hybrid cell extracts
Authors: Taggart R.T. , Francke U.
Published: May 2008

A series of 18 Chinese hamster × human somatic cell hybrid subclones segregating human chromosomes were analyzed by two-dimensional gel electrophoresis to determine the chromosomal location of the human genes responsible for the expression of specific proteins. Two independent methods, side by side comparison and double label autoradiography-fluorography, were used to identify the human proteins that were unambiguously resolved from those of the Chinese hamster (CH). Of the 83 human spots resolved, 22 were determined to be associated with nine specific chromosomes or chromosome regions by correlation with quantitative cytogenetic analysis of the hybrid clones. An additional five spots were associated with three different chromosomes that had identical patterns of segregation. A total of 12 resolvable polypeptides of apparently human origin were present in all 18 hybrid subclones and may be coded for by one of the nine human autosomes that were also consistently present. Future investigations using a variety of available methods to determine the identity of the polypeptide spots will permit the mapping of genes for specific enzymes and for other classes of proteins that are not detectable by the commonly used zymogram methods.
Relationship of Metabolic Alkalosis, Azotemia and Morbidity in Patients with Chronic Obstructive Pulmonary Disease and Hypercapnia
Authors: Ucgun Irfan , Oztuna Funda , Dagli Canan Eren , Yildirim Huseyin , Bal Cengiz
Published: May 2008

Background: Exacerbation of chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality, but the effect of metabolic compensation of respiratory acidosis (RA) on mortality is not fully understood. Objective: To investigate the relationship between metabolic compensation and mortality in COPD patients with RA. Methods: We prospectively investigated all COPD patients with RA admitted to the respiratory intensive care unit between February 2001 and March 2007. Two hundred and thirteen patients (159 male, 54 female; mean age 65 ± 10.8 years) were divided into three groups (71 patients each) according to base excess (BE) levels: (1) low BE, (2) medium BE, and (3) high BE. H+ concentration was calculated according to their standard formula and BE was calculated according to the Van Slyke equation. Results: The overall mortality rate was 24.9%. The group mortality rates were 32, 17 and 25% in the low, medium and high BE groups, respectively (p = 0.001). When patients were divided into three groups according to the HCO3– levels, the group mortality rate was 59.1% in the low HCO3– group and 19.8% in the high HCO3– group. Based on univariate analysis, six factors affecting mortality were identified. However, multivariate analysis showed that the levels of serum HCO3– (p = 0.013; OR: 0.552; CI: 0.345–0.882) and creatinine (p = 0.019; OR: 2.114; CI: 1.132–3.949) had an independent effect. Conclusion: In patients with COPD exacerbation and hypercapnia, the development of sufficient metabolic compensation and adequate renal function significantly decreases mortality.
A quantitative comparison of cytogenetic effects of anti-tumor agents
Authors: Parkes D.J.G. , Scott D.
Published: May 2008

The relative potency of different anti-tumor agents in inducing structural and numerical chromosome abnormalities and SCEs was assessed by making comparisons at equitoxic doses, measured in terms of colony forming ability, in cultured diploid human fibroblasts. At approximately 20% survival the relative potency of X-rays, daunorubicin, nitrogen mustard, adriamycin, and actinomycin D in inducing structural aberrations was 1.0, 0.85, 0.26, 0.22, and zero, respectively. SCE induction was quantitatively unrelated to the induction of chromosome aberrations. No numerical changes were observed. Accurate assessment of the yields of chromosome aberrations requires the use of multiple sampling times in asynchronous populations.
Sister chromatid exchange in human populations: the effect of smoking, drug treatment, and occupational exposure
Authors: Lambert B. , Bredberg A. , McKenzie W. , Sten M.
Published: May 2008

Increased rate of sister chromatid exchange (SCE) in peripheral lymphocytes has been observed in smokers as compared to nonsmokers and in patients receiving certain cytostatic drugs. The increased SCE frequency in smokers was shown to depend on the number of cigarettes smoked per day, as well as on the duration of smoking. DNA crosslinks caused by photochemotherapy against psoriasis, 8-methoxypsoralen plus UVA irradiation (PUVA), as well as by the anti-cancer chemotherapeutic agent CCNU, were shown to be more effective at inducing SCE’s than other types of DNA damage caused by these treatments. These observations suggest that SCE analysis may be used as an indicator of genotoxic exposure in vivo, provided that the various types of DNA damage caused by genotoxic agents and the dose, as well as the time of exposure in relation to the time of sampling, are considered.
Identification of mutagen exposures in the rubber industry by the sister chromatid exchange method
Authors: Sorsa M. , Mäki-Paakkanen J. , Vainio H.
Published: May 2008

The rubber industry is known to use a large and expanding array of chemicals, some of which are experimentally proven mutagens or carcinogens. An association with cancer risk has been shown in several epidemiological studies carried out in the rubber industry. Sister chromatid exchanges were studied in blood lymphocytes of 54 workers from various job categories in two rubber plants and 34 control subjects mainly from office jobs. The highest numbers of SCEs were observed among rubber workers who smoked, but smokers in the control group also differed significantly from non-smokers by their incidence of SCEs. In both rubber plants the highest incidence of SCEs was observed among workers employed in the mixing operations of the rubber chemicals.
A possible mechanism for chemical induction of chromosome aberrations in male meiotic and postmeiotic germ cells of mice
Authors: Generoso W.M.
Published: May 2008

The mechanisms by which chemically induced lesions in the chromosomes of mammalian germ cells are actually converted to aberrations and transmitted to progeny are very complex and little understood. An attempt is made to explain how dominant-lethal mutations and heritable translocations are produced from chemical treatment of meiotic and postmeiotic germ cells of male mice.
The use of Robertsonian translocations in the mouse for studies on non-disjunction
Authors: Searle A.G. , Beechey C.V.
Published: May 2008

In the mouse, gametes with gross chromosome duplications and deficiencies can complement each other to give viable zygotes (with some notable exceptions involving particular chromosomes). These complementation-type offspring can be recognised in intercrosses between translocation heterozygotes in which one parent is homozygous for a recessive genetic marker not carried by the other. This system has been used by Lyon and colleagues (1976) to study non-disjunction in heterozygotes for tobacco mouse and laboratory-derived Robertsonian translocations. Although non-disjunction is frequent in the former group, still higher frequencies are needed for a workable test system in which wild type mice are treated and mated to a tester stock generating many aneuploid gametes. Possible approaches include (1) use of semidominant markers, (2) marking both arms, (3) combining two or three independent Robertsonians in the tester stock, (4) use of compounds of Robertsonians with monobrachial homology, since these give very high frequencies of non-disjunction, (5) generation of a compound of three Robertsonians with tribrachial homology, which should produce aneuploid gametes only. This last seems the most promising approach, if the compound proves fertile, and would be analogous to the isochromosome system of Drosophila.
Contribution of chromosome abnormalities to human morbidity and mortality
Authors: Hook E.B.
Published: May 2008

Estimates of the association of chromosome aberrations with various adverse health outcomes are as follows: embryonic and fetal death (5–28 weeks), 33%; stillbirths, 5–10%; infant and early childhood death, 5–7%; retardation (IQ < 50), 20–35%; (IQ 50–69), 5–15%; criminality and retardation or psychiatric disturbance in males, 3%; other criminality, 0.3–0.8%; birth defects, 2.5–8%; heart defects, 10%; subfertility or infertility, 2–8%; multiple miscarriages, < 1 to 13%; male pseudohermaphroditism, < 25%; and primary amenorrhea, 25%. Variations in rates reflect statistical fluctuations and variations in the selection of populations for study. The estimates are based on currently used techniques; cryptic structural rearrangements may also contribute significantly to these outcomes.
Chromosome aberrations as a cause of subtle teratogenesis and use of the grasshopper neuroblast to test potential mutagens and teratogens
Authors: Gaulden M.E.
Published: May 2008

The possible effects of low doses of environmental mutagens on the human embryo are discussed in terms of chromosome aberrations that could result in subtle teratogenesis, i.e., functional defects not detectable at birth. The action of a mutagen on the cells of an early stage human embryo has the potential of producing teratogenesis by inducing a viable chromosome aberration, e.g., a terminal deletion. Such an event would give rise to a mosaic individual. It is proposed that a functional defect of the central nervous system is the most likely result. The advantages of the neuroblast of the grasshopper embryo for detecting potential mutagens-teratogens are presented. In addition, the mitotic effects of mutagens which may also cause teratogenesis can be easily ascertained in great detail in the neuroblast, which has a short cell cycle (4 h at 38° C) and which can be observed in the living condition.
Chromosomal variability of sex chromosomes and NOR’s in Trichomys apereoides (Rodentia, Echimyidae)
Authors: Souza M.J. , Yonenaga-Yassuda Y.
Published: May 2008

G-banding, C-banding, and silver staining techniques were used to analyze the chromosomes of Trichomys apereoides. In a sample of 22 specimens the diploid number was 2n = 30, with several pairs of biarmed chromosomes and a large metacentric (pair 1) with a secondary constriction, or nucleolar organizing region (NOR), in the short arm. One male had a heteromorphic pair 1, with only one NOR-bearing homolog. C-bands showed constitutive heterochromatin in the centromeric region of almost all autosomes. The X has a large block in the proximal region and an interstitial small band in the long arm. The Y is totally heterochromatic. One heteromorphic female with an increased C-band block in one of the X chromosomes was observed. The Y is a small submetacentric; one male showed a metacentric Y, resulting probably from a pericentric inversion. The sexual bivalent and the synaptonemal complexes of all autosomal bivalents were revealed by silver staining in pachytene cells.
Gene mapping of Microcebus murinus (Lemuridae): a comparison with man and Cebus capucinus (Cebidae)
Authors: Cochet C. , Créau-Goldberg N. , Turleau C. , de Grouchy J.
Published: May 2008

The karyotype of Microcebus murinus (MIM) (Lemuridae) is considered by Dutrillaux (1979) as the closest to the karyotype ancestral to all primates. A large number of homoeologies exists between the banding patterns of MIM chromosomes and those of man (HSA). We report a comparison of the gene maps of these two species which confirms most of these homoeologies. Fifteen cell hybrids were obtained by fusing MIM fibroblasts and an HPRT- Chinese hamster cell line. Twenty-seven enzyme markers were investigated. The following assignments were demonstrated: NP to chromosome MIM 2, homoeologous to HSA 14; the syntenic group PGD—ENOl—PGMl to MIM 3, homoeologous to HSA lp; LDHA to MIM 5, homoeologous to HSA 11; ME1 to MIM 6, homoeologous to HSA 6; the syntenic group LDHB—CS—PEPB—EN02—TPI to MIM 7, homoeologous to HSA 12; the syntenic group AK1—AK3 to MIM 10, which we considered to be homoeologous to HSA 9 (we do not consider MIM 9 to be homoeologous to HSA 9, as does Dutrillaux, 1979); GOT1 to MIM 15, homoeologous to HSA 10; the syntenic group HPRT—G6PD—PGK—GLA to MIM X. Synteny dissociation in three hybrids suggests closer linkage between G6PD and HPRT than between PGK—GLA and HPRT. Three syntenic groups, known in man, were confirmed in MIM but could not be assigned with full confidence: ACPI—MDH1 , MPI—PKM2, andPEPD—GPL GUK1 and PEPC, known to be syntenic in man, were found to be asyntenic in MIM and could not be assigned. PGM2 and SOD1 could not be assigned. A comparison of these gene assignments with those known in Cebus capucinus showed a remarkable homoeology for six chromosomes of the two species.
Human chromosome 2 rod/ring mosaicism: probable origin by prezygotic breakage and intrachromosomal exchange
Authors: Wyandt H.E. , Kasprzak R. , Lamb A. , Willson K. , Wilson W.G. , Kelly T.E.
Published: May 2008

A 5-year-old male with mild mental retardation showed a chromosomal rearrangement involving duplication of part of 2q (2q33.3→2qter) in 70% of metaphases from peripheral blood; the remaining 30% of cells had a rearrangement of chromosome 2 in the form of a ring, viz., r(2)(2p25.2→2q33.2). Both configurations appeared to be missing a tiny portion of 2p (p25.3→pter). All metaphases examined from cultured skin fibroblasts from the child had the abnormal rod configuration of chromosome 2; none had the ring. The pattern of the 2q duplication/2p deletion in the rod is that expected if there were an inversion in a No. 2 in one of the parents. Q-, G-, and R-banding studies, however, revealed both parents to be chromosomally normal. Furthermore, the finding of an inversion would not explain the origin of the ring. The most probable explanation is that neither parent is mosaic for an inversion, but that the rod and ring configurations arose simultaneously from a de novo, prezygotic or early zygotic exchange in a No. 2, either between complementary DNA strands in Gl or by intrachromosomal exchange in S or G2. Differential selection against cells with the ring chromosome in blood and skin probably occurred during subsequent embryological development. Cytoplasmic malate dehydrogenase (MDH1) was excluded from the terminal band of 2p (i.e., 2p25.3) by deletion mapping.
Cytogenetic surveillance of spontaneous abortions
Authors: Morton N.E. , Hassold T.J. , Funkhouser J. , McKenna P.W. , Lew R.
Published: May 2008

During the five years of a cytogenetic study on spontaneous abortions in Hawaii there have been significant increases in the frequencies of triploidy of maternal origin and trisomy 16, a significant decrease in sex chromosome monosomy, and variation without trend in the frequency of tetraploidy. Attempts to explain these results in terms of technical factors or changes in maternal and gestational age have been unsuccessful, as have preliminary attempts to identify viral, pharmacological, or other causes. Apparently the etiology of chromosomal abnormality is variable over a few years even in a stable population. Research to identify these causes is continuing on the supposition that variable risks can be reduced.
The longitudinal differentiation produced by photo-oxidation and acridine-orange staining in eukaryote chromosomes: role and involvement of DNA base composition
Authors: Mezzanotte R. , Ferrucci L. , Marchi A. , Bianchi U.
Published: May 2008

Photo-oxidation and staining with acridine-orange result in a longitudinal green/orange-red/brown-red color differentiation in fixed chromosomes of Drosophila melanogaster, D. virilis, Culiseta longiareolata, and Mus musculus. Such a result has been correlated with specific DNA base sequences situated in specific chromosomal areas. In fact, given the known base composition of satellite DNA’s in three of the species we studied, a correspondence seems to exist between molecular hybridization in situ of AT-rich satellite DNA’s and the location of specific stain reactions in specific chromosome regions. Moreover, our results support previous findings suggesting preferential guanine destruction as a consequence of photo-oxidation.
In vivo sister chromatid exchanges in the euchromatin and constitutive heterochromatin of the Indian mole rat, Nesokia indica
Authors: Thelma B.K. , Rao S.R.V.
Published: May 2008

Distribution of in vivo SCEs in euchromatin and constitutive heterochromatin of Nesokia indica has been studied. The distinct partitioning of the euchromatin and constitutive heterochromatin into different arms of the large X chromosome greatly facilitates such a comparison. The constitutive heterochromatin showed a higher SCE rate per unit length than the total euchromatin. However, between the two types of chromatin in the X itself there was no significant difference. These values were also comparable to that observed for the largest autosome. This study suggests that factor(s) other than chromatin condensation, DNA base composition, and DNA replication kinetics is (are) responsible for the formation of SCEs.
Factors affecting the displacement of human chromosomes from the metaphase plate
Authors: Ford J.H. , Lester P.
Published: May 2008

In order to elucidate some of the factors influencing the attachment of chromosomes to spindles, an analysis was made of the displacement of chromosomes from the metaphase plate in preparations that received no colchicine or hypotonic treatment. Displaced chromosomes were identified by Giemsa banding. Three hypotheses were tested and led to the following conclusions: (1) Chromosomal displacement is a function of size—smaller chromosomes are displaced more often than larger ones. (2) The position of the centromere does not influence chromosome displacement. (3) The amount of centromeric heterochromatin in the chromosome has a highly significant effect on displacement—chromosomes with more heterochromatin are displaced more often than those with less.
Establishment of Chinese hamster stocks homozygous for a reciprocal translocation originally induced by testicular X-irradiation
Authors: Tateno H. , Mikamo K.
Published: May 2008

Following testicular X-irradiation of Chinese hamster (Cricetulus griseus) males eight progeny (five males and three females) with reciprocal translocations (heterozygotes) were obtained. They were all phenotypically normal but semi-sterile. Homozygotes were produced successfully with CHAT3 (2p –;9q + ) and CHAT5 (2–;8q+). They were proven to be fertile. Thus, two homozygous stocks with distinct marker chromosomes were established. CHAT3 homozygotes have shown a high incidence of diabetes, while CHAT5 homozygotes had no genetic burden. Progeny tests of outcrosses and intercrosses with the heterozygotes and homozygotes were performed in both stocks. Karyological analysis of the first cleavage division showed the marker chromosomes of both stocks to be useful in distinguishing the paternal chromosome complements from the maternal ones.
Regional assignment of the structural gene for human acid β-glucosidase to q42→qter on chromosome 1
Authors: Devine E.A. , Smith M. , Arredondo-Vega F.X. , Shafit-Zagardo B. , Desnick R.J.
Published: May 2008

The structural gene for human acid β-glucosidase (GBA) has been regionally assigned to a narrow region on chromosome 1 using somatic cell hybridization, specific immunoprecipitation, and assay with the natural substrate. A human fibroblast line, 46, XX, del(1)(pter→q42:), was fused with mouse RAG fibroblasts and the heterokaryons were subcloned. All hybrid subclones containing a normal chromosome 1 were positive for GBA. In contrast, subclones with a single del(1) were negative for GBA by both immunoprecipitation and natural substrate assays. These results were consistent with the previous assignment of GBA to the region 1p11→qter and further localized the gene to the narrow region 1q42→qter.
Is DNA methylation responsible for mammalian X chromosome inactivation?
Authors: Miller D.A. , Okamoto E. , Erlanger B.F. , Miller O.J.
Published: May 2008

Mohandas et al. (1981) have proposed that mammalian X chromosome inactivation involves segmental methylation of cytosine residues in the DNA at multiple sites along the X chromosome. Using antibodies specific for 5-methylcytosine, we have found no detectable difference in the extent of methylation of the DNA in the two X chromosomes of owl monkey or human females. Thus inactivation (facultative heterochromatization) of the X chromosome is not due to, or associated with, intense DNA methylation comparable to that seen in most constitutive heterochromatin.
Contribution a la cytotaxonomie des Soricidés (Mammalia, Insectivora) de l'Afrique occidentale
Authors: Meylan A. , Vogel P.
Published: May 2008

Chromosomes analysis of 28 shrews belonging to the genus Crocidura from West Africa allowed the detection of five new karyotypes: C. wimmeri (2n = 50, NF = 84), C. cf. gracilipes (56/86), C. cf. nimbae (46/68), and C. cf. planiceps (44/72). Among the individuals identified morphologically as C. poensis (52/70) a distinct species was recognized on the basis of its chromosome complement, C. nigeriae (50/76). The karyotype of C. occidentalis was confirmed with the study of another subspecies, C. occidentalis manni (50/66). An identical chromosome set characterizes C. odorata giffardi and provides evidence for its relationship with C. occidentalis.
Cytogenetics of preimplantation embryos produced by pigs heterozygous for the reciprocal translocation (4q+;14q–)
Authors: Popescu C.P. , Boscher J.
Published: May 2008

The karyotype of embryos and newborns produced by pigs heterozygous for the reciprocal translocation rcp(4q+;14q–) were studied. Forty-seven 9- to 10-day-old embryos were recovered. Only 27 (57.3%) could be karyotyped. Of these, 16 (59.3%) had normal or balanced heterozygous karyotypes, and 11 (40.7%) had unbalanced ones. Six different types of unbalanced karyotypes were identified. No unbalanced karyotypes was found in 38 newborn piglets produced by five heterozygous animals. It was concluded that unbalanced karyotypes are lethal at the embryonic stage.
Complex evolution of sex chromosomes in Gerbillidae (Rodentia)
Authors: Viegas-Péquignot E. , Benazzou T. , Dutrillaux B. , Petter F.
Published: May 2008

The sex chromosomes of 11 species of Gerbillidae (Meriones tristrami, M. crassus, M. libycus, M. persicus, M. unguiculatus, Gerbillus hesperinus, G. nigeriae, G. gerbillus, G. campestris, Gerbillurus tytonis, and Taterillus gracilis) are reported. A very complex evolution of the X chromosome and, to a lesser degree, of the Y chromosome was observed, including several inversions, translocations with autosomes, and an increase in heterochromatin. The role of constitutive heterochromatin, isolating autosome and gonosome segments in translocations (thus preventing any position effect), is discussed. The sequence of rearrangements affecting the sex chromosomes is considered with a view toward establishing the phylogenetic relationship of the species studied. The tendency to accumulate the same rare type of rearrangement, namely, gonosome-autosome translocations, is another demonstration that chromosomal evolution is not random in a given group of species.
The cytogenetic response of Fanconi’s anemia lymphoblastoid cell lines to various clastogens
Authors: Cohen M.M. , Fruchtman C.E. , Simpson S.J. , Martin A.O.
Published: May 2008

Cytogenetic damage was investigated in long term lymphoid cell lines derived from normal individuals, patients with Fanconi’s anemia (FA), ataxia telangiectasia (AT), xeroderma pigmentosum (XP), and FA heterozygotes. The cell lines were exposed to various concentrations of four chemical clastogens, including the alkylating agents diepoxybutane, mitomycin C, and nitrogen mustard, as well as the antitumor glycopeptide bleomycin. The FA cells exhibited chromosomal hypersensitivity to all four clastogens and could be distinguished from the other genotypes. AT cells were identified by bleomycin, while FA heterozygotes could not be reliably detected. Discriminant function analysis was used to describe the cytogenetic response to the various clastogens. This method might prove useful for evaluation and classification of multivariate chromosome breakage studies.
The origin of mitotic sex-chromosome association in the brush-tailed possum, Trichosurus vulpecula (Marsupalia:Phalangeridae)
Authors: Stock A.D. , Mengden G.A.
Published: May 2008

Nonrandom associations between the sex chromosomes of the brush-tailed possum, Trichosurus vulpecula, were found to be due to association of nucleolar organizer regions (NOR’s) on the X and Y chromosomes. NOR association was also observed between an autosome and the X chromosome. These findings, based on silver staining, are in contrast to the report of Murray (1977), who observed sex-chromosome association in this animal and indicated that these nonrandom associations may reflect an association between heterochromatic regions during interphase. We observed only two pairs of NOR’s per cell in this animal, one autosomal and one on the sex chromosomes, rather than the several such regions observed by Murray, who used an N-banding technique. We discuss the problem of nonhomologous chromosome association in mammalian cells as influenced by heterochromatin and NOR’s and find little support for nonhomologous chromosome associations at mitotic metaphase due to heterochromatin association.
Scanning electron microscopy of variations in human metaphase chromosome structure revealed by Giemsa banding
Authors: Harrison C.J. , Allen T.D. , Harris R.
Published: May 2008

Trypsinization, used as a pretreatment for Giemsa banding human chromosomes, produced a progressive degradation of metaphase chromosome structure. Over the visible range of G-banding in the light microscope various levels of chromosome structure were revealed in the scanning electron microscope.
Cytogenetic analysis of Q-banded pronuclear chromosomes in fertilized Syrian hamster eggs
Authors: Martin R.H. , Balkan W. , Burns K.
Published: May 2008

The frequency and type of chromosome abnormalities were analyzed in 917 female pronuclei in Syrian hamster eggs fertilized by human sperm. Analysis at this stage allows detection of errors which have occurred during meiosis I and II. The chromosomes were Q-banded to identify individual chromosomes and detect subtle alterations. Thirty-three (3.6%) of the hamster egg complements were abnormal: 19 (2.1%) were hypohaploid, seven (0.76%) were hyperhaploid, two (0.2%) had double aneuploidy, and five (0.5%) had a structural chromosome abnormality. Since there were significantly more hypohaploid than hyperhaploid complements, a conservative estimate of aneuploidy can be derived by doubling the frequency of hyperhaploid complements. Thus a minimal estimate of aneuploidy (single, 1.5%, and double, 0.2%) is 1.7% and a minimal estimate of the total frequency of abnormalities is 2.2%. All chromosome groups were represented among the aneuploid complements suggesting that all chromosomes are susceptible to non-disjunction.
Complex chromosome homologies between the rhesus monkey (Macaca mulatta) and man
Authors: Estop A.M. , Garver J.J. , Egozcue J. , Meera Khan P. , Pearson P.L.
Published: May 2008

The chromosome localization and gene synteny of soluble malate dehydrogenase (MDH1), soluble isocitrate dehydrogenase (IDH1), mitochondrial superoxide dismutase (SOD2), phosphoglucomutase-3 (PGM3), mitochondrial malate dehydrogenase (MDH2), (3-glucuronidase (GUSB ), nucleoside phosphorylase (NP), pyruvate kinase M2 (PKM2), hexosaminidase A (HEXA), inosine triphosphatase (ITPA), and N-acetyl-α-D-galactosaminidase (NAGA) were determined in the rhesus monkey using somatic cell hybrids. Comparison with the human and Pongidae syntenic groups shows that chromosome banding homologies do not always correlate with gene mapping data.
C-band patterns of chromosomes in 17 strains of mice
Authors: Yoshida M.C. , Kodama Y.
Published: May 2008

Differences in the size and distribution of chromosomal C-bands were investigated in 17 strains of Mus musculus. Each strain was found to have a characteristic C-band pattern. Closely related strains, substrains, and congenic strains, e.g., DDD and DRC, BALB/c and BALB/cAn, and CBA/J and CBA/H-T6, showed a similar C-band pattern, whereas striking dissimilarities in the C-band pattern was observed between the related strains, DDD and DHS, and SJL and SWJ, which were established independently from noninbred stocks of dd and Swiss mice, respectively. Virtually every autosome except for 1 and 2 showed C-band variation among the strains. The size of the C-band on 1,2, and the X appeared to be fairly constant among the strains. All chromosome pairs were homomorphic in each inbred animal; the between-strain difference in the C-band size was most easily observed in F1hybrids which showed the heteromorphic C-band patterns, expected from the parents. Measurements of the chromosome lengths of the heteromorphic pairs in a (C57BL/6J x DDD) F1 hybrid disclosed that homologues which had different size C-band had significantly different lengths, and homologues, one of which lacked C-band material, were the same length. Heteromorphism in the length of Y chromosome was also found; BALB/cAn had a Y smaller than the 19. These chromosome markers appear to be useful for characterizing each strain as well as for monitoring inbred stocks.
Spontaneous heteroploidy in one-cell mouse embryos
Authors: Martin-DeLeon P.A. , Boice M.L.
Published: May 2008

First cleavage divisions were analyzed, after chromosome banding, in 321 zygotes recovered from superovulated, outbred ICR mice 33–35 h after injection of human chorionic gonadotropin. With 72.1% of all zygotes at metaphase and late prophase analyzed, there was 87% diploidy, 3.6% trisomy, 2.5% monosomy, 0.4% structural rearrangement, and 0.93% triploidy. Aneuploid zygotes in which there were 37 or 38 chromosomes accounted for 6.5% of the population with both haploid complements analyzable. In 45 diploid zygotes in which only one complement was analyzable, there was 93.4% haploidy, 2.2% disomy, and 4.4% hypoploidy. The chromosome most often involved in aneuploidy was the 19. The parental origin of the chromosome anomalies was determined on the basis of differential condensation of the chromosomes. The source of trisomy was shown to be the male in three and the female in five of the eight cases determined. This indicates a paternal contribution to trisomy and a female nondisjunction frequency of 1.5% (five of 321). For monosomy where the origin was identified in five of the cases, the male complement was implicated in three zygotes. The single break was seen in a sperm-derived chromosome. Two of the three triploids were dispermic and one was digynic. The outbred Swiss mouse might be a useful model for studying factors responsible for the induction of cytogenetic anomalies in early development of mammals.
The human phosphoserine phosphatase gene (PSP) is mapped to chromosome 7 by somatic cell genetic analysis
Authors: Sparkes R.S. , Mohandas T. , Sparkes M.C.
Published: May 2008

Human phosphoserine phosphatase (E.C. 3.1.3.3) (PSP), a phosphohydrolase, participates in the biosynthesis of serine from carbohydrates (Moro-Furlani et al., 1980). Starch gel electrophoresis has identified isoenzymes and rare allelic variants. More common electrophoretic variation is thought to be due to secondary nongenetic modification. Using starch gel electrophoresis of interspecific somatic cell hybrids, we have been able to assign the gene for this enzyme to human chromosome 7.
On the types of chromosomal aberrations induced by 8-methoxypsoralen
Authors: Hook G.J. , Heddle J.A. , Marshall R.R.
Published: May 2008

When activated by near-ultraviolet light, 8-methoxypsoralen can react with pyrimidine bases to produce mono-adducts in DNA. Upon further irradiation these mono-adducts can be converted to interstrand crosslinks, but if the re-irradiation is carried out in the absence of unbound 8-methoxypsoralen, no new mono-adducts can be formed. The effects of re-irradiation are, therefore, a consequence of the conversion of mono-adducts into crosslinks. Here we report the types of chromosomal aberrations produced by re-irradiation and, hence, by DNA crosslinks. Our results demonstrate that crosslinks induce a wide variety of chromosomal aberrations in the first division after treatment. In addition, crosslinks are shown to induce new aberrations in second-division cells, a result which shows that the crosslink or some lesion derived from it survives at least one round of DNA replication.
Numerous chromosomal polymorphisms in a natural population of rice rats (Oryzomys, Cricetidae)
Authors: Koop B.F. , Baker R.J. , Genoways H.H.
Published: May 2008

Based on G- and C-banded karyotypes of 10 specimens of rice rats, genus Oryzomys (a member of the macconnelli-capito complex but species identification is not possible at this time) from a single isolated population, we found at least nine different centric fusion/fission polymorphisms. No two individuals examined had the same karyotype. Polymorphic variation appears to be stable in the population and not the result of hybridization, human disturbance, or non-specific mutagenic agents. Among the 14 largest chromosomes, polymorphism is restricted to fusion/fission rearrangements. Among the smaller ones, there is polymorphism in the total number of euchromatic arms, which indicates that rearrangements other than fusion/fission exist within our sample. Data from these rice rats document the presence of a greater number of chromosomal polymorphisms within a single, natural population than have previously been reported in a higher vertebrate.
The chromosomes of Muntiacus feae
Authors: Soma H. , Kada H. , Mtayoshi K. , Suzuki Y. , Meckvichal C. , Mahannop A. , Vatanaromya B.
Published: May 2008

The karyotype of a female Muntiacus feae is described. It comprises 13 chromosomes, three submetacentrics, and ten acrocentrics. Chromosome 1 is the sex chromosome. This individual was heterozygous for a Robertsonian translocation between chromosomes 2 and 7.
Heterochromatin heterogeneity in Chinese hamster sex bivalents
Authors: Murer-Orlando M. , Richer C.-L.
Published: May 2008

The heterochromatin of the Chinese hamster sex chromosomes was analyzed by different banding techniques. Combined results obtained after differential Ba(OH)2 treatment, BrdU incorporation, Giemsa 11, and staining with quinacrine permitted the characterization of different regions in the heterochromatic portions of the X and Y chromosomes. In the light of these observations, the chiasma observed in the sex bivalent of Chinese hamster spermatocytes was localized within specific heterochromatic regions. The homologous segments consist of the entire short arm of the Y and the distal end of the long arm of the X up to band q21. These regions are probably not rich in highly repetitive DNA sequences, which are more resistant to alkali denaturation, or in satellite DNA, which is stained by Giemsa 11. Thus the heterochromatin in the homologous regions of the sex chromosomes allows the formation of a chiasma. The heterogeneity found in these heterochromatic regions may help to establish a more precise relationship between heterochromatin and recombination.
Heterochromatin variation and sex chromosome polymorphism in Nesokia indica: a population study
Authors: Rao S.R.V. , Vasantha K. , Thelma B.K. , Juyal R.C. , Jhanwar S.C.
Published: May 2008

Nesokia indica, the Indian mole rat, exhibits extensive variability (polymorphism) for the constitutive heterochromatin of the X and Y chromosomes. These polymorphic X and Y types range from a large metacentric chromosome to a small acrocentric one and occur in different frequencies in the population. On the assumption that there is random mating among individuals carrying these various X and Y chromosomes, the population shows Hardy-Weinberg proportions for the genotypes. However, notwithstanding the partial or total loss of constitutive heterochromatin of the X and Y chromosomes in a few individuals, its retention in most of the animals seems obligatory to the population at large. Hence, we suggest that the C-heterochromatin plays a “regulatory” role in the population dynamics of this species.
A detailed method for obtaining preparations of human sperm chromosomes
Authors: Martin R.H.
Published: May 2008

A detailed technique is described for obtaining preparations of the chromosome complements of human sperm by fertilization of hamster eggs and analysis of the male pronucleus. Some of the more difficult aspects and important steps are emphasized. Technical data from 17 consecutive experiments are presented to provide an estimate of the number of karyotypes which can be obtained in an experiment.