bluuebunny/crossref_metadata_2025_split huggingface dataset:
A genetic system for alternative stable characteristics in genomically identical homozygous clones
Authors: Sonneborn T. M. , Schneller Myrtle V. 
Published: May 2005

AbstractParamecium tetraurelia, stock d113, although completely homozygous, produces two kinds of genomically identical clones: N (nondischarge) clones incapable of trichocyst exocytosis (discharge) from intact cells in response to picric acid; and D (discharge) clones that do respond. These alternatives are irreversibly determined (at 27°C) during a determination sensitive period the first day after fertilization (autogamy, conjugation, or cytogamy): D parents are always determined to produce D progeny; N parents produce mostly N progeny if kept in exhausted medium, but mostly D progeny if kept in bacterized nutrient medium, throughout the sensitive period. If connecting bridges between mates persist long after the time for pair separation, the N member of N×D conjugant and cytogamous pairs produces D progeny even if exposed to exhausted medium throughout the sensitive period, thus indicating the presence in D mates of a D‐determining cytoplasmic factor, δ, which overrides effects of external conditions. N and D determinations are brought about on newly developing somatic nuclei (macronuclear anlagen). After macronuclear development has been completed, determination is irreversible in it and its descendant macronuclei. M (mixed) clones produce N, D, and partial D cells; within these clones, diverse subclones can be selected. Crosses of d113 (N)×standard wild stock 51 (D) yield no segregation in F2, indicating no genomic difference between d113 (N) and wild type (D), δ may be a genic product regulating its own production. This results in “cytoplasmic inheritance” of D vs N in crosses of D×N followed by exhausted medium during the sensitive period. As with the only other well‐analyzed comparable example, mating types, neither a genetic nor an epigenetic interpretation has yet been excluded for this system of developmental differentiation.
Mutations affecting the initiation of plasmodial development in Physarum polycephalum
Authors: Gorman Jessica A. , Dove William F. , Shaibe Eva 
Published: May 2005

AbstractIn the heterothallic myxomycete Physarum polycephalum, uninucleate amoebae normally differentiate into syncytial plasmodia following heterotypic mating. In order to study the genetic control of this developmental process, mutations affecting the amoebal‐plasmodial transition have been sought. Numerous mutants characterized by self‐fertility have been isolated. The use of alkylating mutagens increases the mutant frequency over the spontaneous level but does not alter the mutant spectrum. Three spontaneous and 14 induced mutants have been analyzed genetically. In each, the mutation appears to be linked to the mating type locus. In three randomly selected mutants, the nuclear DNA content is the same in amoebae and plasmodia, indicating that amoebal syngamy does not precede plasmodium development in these strains. These results indicate that a highly specific type of mutational event, occurring close to or within the mating type locus, can abolish the requirement for syngamy normally associated with plasmodial differentiation. These mutations help define a genomic region regulating the switch from amoebal to plasmodial growth.
Differential expression of alloantigens of the major histocompatibility complex on unfertilized and fertilized mouse eggs
Authors: Heyner Susan , Hunziker R. D. 
Published: May 2005

AbstractMouse oocytes at the dictyate and metaphase II stages as well as fertilized eggs have been studied by indirect immunofluorescence for the expression of H‐2 histocompatibility antigens on surface membranes. Serologically specific reactivity to H‐2 antibody was observed as patchy fluorescence distributed over the surface of the oocyte membrane. In contrast, one‐cell zygotes exhibited variable reactivity, and early two‐cell stages were negative. Absorption studies confirmed the serologic specificity of the reactivity on oocytes, which could be shown to be due to H‐2 antibody. The results suggest that fertilization results in altered expression of major histocompatibility complex surface antigens, and confirms earlier studies that cleavage stage mouse embryos are not reactive with H‐2 antibody.
Patterns of protein synthesis following heat shock in pupae of Drosophila melanogaster
Authors: Chomyn Anne , Moller Galina , Mitchell Herschel K. 
Published: May 2005

AbstractPupae of Drosophila melanogaster were heat‐shocked under conditions required to induce phenocopies in more than 90% of the flies that subsequently emerge. The effects of these treatments on protein synthesis in two tissues (thoracic epithelium and brain) were followed for several hours after the heat treatments. Results from pulse‐labeling and protein separations on sodium dodecylsulfate (SDS) acrylamide gels showed a virtually complete cessation of protein synthesis immediately after the shock, followed by a noncoordinate resumption of the starting pattern. Similar experiments following double heat shocks demonstrated a more rapid resumption of synthesis of heat shock proteins after two successive heat treatments than after a single one.
Maternal X chromosome expression in mouse chorionic ectoderm
Authors: Frels William I. , Rossant Janet , Chapman Verne M. 
Published: May 2005

AbstractAn electrophoretic variant of the X‐linked enzyme phosphoglycerate kinase (PGK‐1) has been used to study regulation of X chromosome expression in the diploid derivatives of the trophectoderm at 8–8.5 days post coitum in the mouse. These derivatives included the chorionic ectoderm and the polar trophoblast. The biochemical analysis suggests that only the maternally derived X chromosome (Xm) is expressed in the diploid trophectoderm derivatives. Cell selection and maternal tissue contamination were ruled out as possible causes of the observed Xm expression. From these and other results, we conclude that all derivatives of the trophectoderm, along with the primitive endoderm, express only Xm, whereas derivatives of the primitive ectoderm show random X chromosome expression.
Tissue microenvironment and the genetic control of hair pigment patterns in mice
Authors: Galbraith Donald B. , Wolff George L. , Brewer Nancy L. 
Published: May 2005

AbstractThis study was conducted to assess microenvironmental variability within integumental tissue of genetically identical mice with respect to a specific cellular response: cyclic synthesis of yellow and black pigment by hair bulb melanocytes. Crosses were performed within and between inbred strains of mice that were isogenic with the exception of a single gene substitution at the agouti locus. Agouti locus genes included the Avy, Aw, A, atd, at, ax, am, and a alleles. The pigment patterns of dorsal, flank, and ventral hairs of the first and third hair generations and of hairs growing in special integumentary areas such as the pinna, tail, and hind foot were studied. It was found that the amount of yellow pigment synthesized by hair bulb melanocytes within genetically identical mice is both agedependent and conditioned by the integumentary environment. Furthermore, the special integumentary regions produce hairs with a variety of pigment patterns in which the distribution and relative amounts of black and yellow pigments do not necessarily conform to dominance relationships expected among agouti locus alleles as judged by their effects on the pigmentation of the dorsal pelage. We conclude that within genetically uniform integumental tissues, microenvironmental differences occur and are reflected as alterations in the metabolic pattern of differentiated cells.
Genomic exclusion in Tetrahymena thermophila: A cytogenetic and cytofluorimetric study
Authors: Doerder F. P. , Shabatura S. K. 
Published: May 2005

AbstractGenomic exclusion is an aberrant form of conjugation of Tetrahymena thermophila in which the genome of a defective conjugant is excluded from the genotype of the exconjugant progeny. This paper is concerned with the cytogenetic and nucleocytoplasmic events of genomic exclusion in senescent clones A*III and C*. In crosses between A*III or C* and strain B, functional, haploid gametic nuclei are formed only in the strain B cell. In some instances one of the gametic nuclei divides prior to transfer of the migratory gametic nucleus, and both products then undergo DNA synthesis. Two alternative cytogenetic pathways are followed after transfer of the migratory nucleus. In the first, the conjugants separate without further micronuclear divisions. This pathway was most common in A*III genomic exclusion. In exconjugants the former gametic nuclei undergo both DNA synthesis and (presumably) intranuclear separation of centromeres to restore micronuclear diploidy. The old macronucleus of each exconjugant is retained without autolysis. This class of exconjugant survives and contributes genes to future sexual progeny. In the second cytogenetic pathway the gametic nuclei divide and macronuclear anlagen are formed, as in normal conjugation. This pathway was more common in C* genomic exclusion. The initial DNA content of the anlagen ranges from haploid to diploid. Following two to three rounds of DNA synthesis, further macronuclear development ceases and the anlagen appear to undergo autolysis. The old macronucleus condenses and also undergoes autolysis, as in normal conjugation. Except for rare C* exconjugants, in which macronuclear development is completed, anlagen‐bearing genomic exclusion exconjugants die. Death may be caused by aneuploidy, errors in the timing or receptivity to signals for autolysis, or the inability of anlagen‐bearing exconjugants to feed. Anlagenbearing conjugants are frequently abnormal with respect to the number of anlagen and micronuclei. Most of the anomalies can be explained by postulating errors in the timing of both developmental signals and nuclear divisions. Rare conjugants in which gametic nuclei divide but do not give rise to macronuclear anlagen are also observed. In these instances, the old macronuclei condense and undergo autolysis. Destruction of the old macronucleus therefore is independent of the presence of macronuclear anlagen and requires cell pairing in order to be initiated.
Complex cis‐acting regulatory genes demonstrated in Drosophila hybrids
Authors: Dickinson W. J. 
Published: May 2005

AbstractDrosophila heteroneura and D differens are closely related, interfertile species of the Hawaiian picture‐winged group. They display marked qualitative and quantitative differences in the pattern of expression of alcohol dehydrogenase (ADH) and an aldehyde oxidase (AO‐1). These presumptive regulatory differences are revealed by comparisons of the relative levels of these enzymes in various tissues in larvae and adults. In hybrids produced between parents carrying different electrophoretic alleles at the structural loci for these two enzymes, each allele is expressed according to the developmental program characteristic of the parent from which it was derived. This result indicates control of the differences in pattern of expression by one or more cis‐acting sites associated with each structural locus. The distribution of activity among all the three forms of these dimeric enzymes produced in hybrids indicates that the pattern differences reflect differential accumulation of enzyme molecules, not altered catalytic properties. As expected, the regulatory differences segregate with the electrophoretic markers in backcrosses.
Genetic determination of the developmental program for maize scutellar alcohol dehydrogenase: Involvement of a recessive, trans‐acting, temporal‐regulatory gene
Authors: Lai Yiu‐Kay , Scandalios John G. 
Published: May 2005

AbstractThe developmental program of alcohol dehydrogenase (ADH) activity in the scutellum of maize strain R6‐67 is different from that of W64A. The level of scutellar ADH activity in R6‐67 remains relatively high during the course of early sporophytic development as compared to the commonly observed pattern. In the typical inbred strain W64A, the activity of ADH declines substantially during that period. The variance values from the crosses between R6‐67 and W64A reveal that the trait is under genetic control. Detailed genetic analysis suggests that a single gene is responsible for the altered developmental program of ADH activity in R6‐67. This gene meets the criteria for temporal regulatory genes and is different from Adh2, the structural gene which codes the ADH‐2 isozyme. We have designated this gene as Adr1 (alcohol dehydrogenase regulator, #1). Adr1 is unlinked to Adh2. There is no de novo synthesis of ADH in the scutellum during germination, and the difference in the activity level reflects the difference in the amount of enzyme protein as demonstrated by density labeling and rocket immunoelectrophoresis. Thus, it appears that Adr1 may regulate the degradation of ADH.
Mutations specific to spore maturation in the asexual fruiting body of dicytostelium discoideum
Authors: Williams Keith L. , Welker Dennis L. 
Published: May 2005

AbstractThree mutations affecting spore maturation in the asexual fruiting body of Dictyostelium discoideum are assigned to a new locus, sprJ, on linkage group IV. Strains carrying mutations at the sprJ locus do not form mature spores, yet the cell patterning (spore, stalk and disc cell ratios) is apparently normal. These mutations will be useful to delineate branch points between the cell patterning and spore maturation pathways. There are some unusual features of the sprJ‐containing mutants. In particular each of the parent strains of the three mutants has incomplete spore maturation as determined by colony‐forming ability after heat shocking at 45°C. A mutation allowing growth in the presence of benlate (600 μg/ml), benA351, is mapped to linkage group I.
Inhibition by CIPC of mitosis and development in Dictyostelium discoideum and the isolation of CIPC‐resistant mutants
Authors: White Eileen , Scandella Dorothea , Katz Eugene R. 
Published: May 2005

AbstractThe anti‐mitotic herbicide isopropyl N‐(3‐chlorophenyl) carbamate (CIPC) prevents the growth of amoebae of Dictyostelium discoideum without killing the cells for a period of time equivalent to one generation. During in‐hibition, amoebae accumulate in prophase and metaphase of mitosis. After removal of CIPC, they continue through mitosis and then divide.The addition of CIPC to amoebae under starvation conditions prevents aggregation and concomitant cell elongation. The cells, however, do not lose their ability to adhere to a surface, and they remain viable. When CIPC is added to amoebae which have formed streams, it leads to the disintegration of streams into small clusters of cells and to a loss of cell elongation.Post‐aggregation stages of development can be inhibited by CIPC at the mound, slug, or Mexican hat stages. Slugs break apart into distinct aggregates.Mutants resistant to CIPC can be obtained easily. Among these mutants, many become temperature sensititive for growth (27°C) or development (27°C or 15.5°C). Others show various abnormalities at the normal temperature (22°C). Most mutants are cross resistant to the microtubule inhibitors nocodazole and thiabendazole, and some are also resistant to CIPC during development.
Genetic control of the developmental program of L‐glycerol‐3‐phosphate dehydrogenase isozymes in Drosophila melanogaster: Identification of a cis‐acting temporal element affecting GPDH‐3 expression
Authors: Bewley Glenn C. 
Published: May 2005

AbstractThe complete developmental program of glycerol‐3‐phosphate dehydrogenase in wild type Drosophila is described with respect to activity, isozyme expression, and GPDH‐specific CRM. Variants of this developmental program have been isolated from natural populations which affect the rate of accumulation of only the GPDH‐3 isozyme in both the larval and adult stages of development. This activity variation segregates as a single gene which is tightly linked to the structural element on Chromosome II, exhibits cis‐control, and is tissue specific in expression. This gene meets all the criteria for temporal regulatory genes.
The immaturity interval in Tetrahymena: Genetic and environmental sources of variation
Authors: Nyberg Dennis , Bishop Patricia 
Published: May 2005

AbstractThe development of sexual maturity has been studied in Tetrahymena hegewischi. Progeny lines do not typically change from immaturity to mating with all different mating types during a single test interval, but about 30% do mature abruptly. Some testers are more likely than others to participate in the earliest mating reactions of progeny lines which do not mature abruptly. Subcaryonidal vegetative pedigrees of 10 pairs from 4 crosses revealed considerable intrapair variation in the time, measured in fissions, of maturity. The average intrapair coefficient of variation was 20%. A nested ANOVA revealed significant genomic effects on the immaturity interval, but no significant cytoplasmic or caryonidal effects; 56% of the total variation was non‐genomic. Growth in different environments had highly significant effects on the immaturity interval. Subclones grown at 27°C with alternate day transfers took on the average 2 to 3 times as many fissions to mature as sister subclones grown at 27°C with daily transfers. Subclones grown at 18°C or 34°C and transferred on alternate days had intermediate maturation times. The greatest range in the immaturity interval among lines of the same genotype was from 34 to 143 fissions. The development of maturity in this species involves genetic control of timing, but the genetic differences are obscured by a large amount of intraclonal variation and sensitivity to the environment.
The developmental appearance of androgen receptor protein and androgen inducibility of the gus gene complex in mouse kidney
Authors: Paigen Kenneth , Peterson Janice 
Published: May 2005

AbstractDuring postnatal development of mouse kidney the androgen responsiveness of epithelial cells for β‐glucuronidase induction, cellular hypertrophy, and other enzyme inductions appears coincidentally with a rise in androgen receptor protein. Initially, a low level of receptor is present but no response is seen. Beginning at about 12 days of age responsiveness begins to increase, reaches a half‐maximal level at 18–20 days, and full responsiveness by 28–30 days. The limiting factor appears to be levels of androgen receptor protein.Our experiments shed no light on the question of why each androgen responsive cell type in the organism differentiates the capacity to induce a different array of proteins. However, they do suggest that responsiveness of the β‐glucuronidase gene does not appear until a minimum threshold level of receptor is exceeded, and that the response of the gene may not be saturated even at the highest levels of receptor reached.
Developmental controls of morphological mutants of Phaseolus vulgaris L.: Differential expression of mutant loci in plant organs
Authors: Shii C. T. , Mok M. C. , Mok David W. S. 
Published: May 2005

AbstractDevelopmental controls of morphological mutants of Phaseolus vulgaris L. conditioned by two independent loci, DL1 and DL2, were examined through grafting experiments and hydroponic studies. Phenotypes of mutant classes were duplicated by unions of scions and stocks derived from different genotypes. Results indicate that DL1 and DL2 regulate a root and shoot factor respectively, contributing to the mutant types. The allelic dosages of DL1 in the root and DL2 in the shoot rather than the genotype of the whole plant per se determine the severity of the mutant expression. Plants heterozygous for both loci with a temperature‐sensitive expression of the mutant phenotype were used to determine physiological components involved. The primary abnormal developmental event associated with the appearance of mutant phenotypes, the restricted root growth at high temperature, could be overcome by the addition of cytokinin in hydroponic solution. These observations suggest that DL1 and DL2 may be related to the regulation of hormonal function or metabolism.
Enzyme patterns in trisomy 19 of the mouse
Authors: Fundele Reinald , Bücher Theodor , Gropp Alfred , Winking Heinz 
Published: May 2005

AbstractActivity patterns of cytosolic and mitochondrial enzymes of carbohydrate and amino acid metabolism have been measured in murine trisomy 19. In spite of marked hypoplasia, no significant alterations of the patterns (per gram of organ weight) were observed, with the exception of glutamate oxaloacetate transaminase (GOT‐1), and phosphoglycerate mutase (PGAM). Clear‐cut gene dosage effects in liver, brain, heart, skeletal muscle, and erythrocytes of fetal and newborn mice, confirm the assignment of GOT‐1 to chromosome 19. Data obtained for PGAM demonstrate that one of the two different subunits leading to organ‐specific isozyme patterns of the dimer enzyme protein is coded on chromosome 19 (gene Pgam‐1). Dosage effects are fully expressed in liver, brain, and erythrocytes (AA‐type isozyme), but not in skeletal muscle (BB‐type isozyme). Dosage effects on the hybrid AA‐AB‐BB‐isozyme pattern in the course of development of the heart muscle, were demonstrated by means of quantitative activity measurement after electrophoretic separation. The comparison of enzyme patterns of eusomic and trisomic erythrocytes, produced after injection of fetal stem cells into irradiated adult carriers (transplantation chimaeras), revealed enzyme activity ratios that were similar to those produced by erythrocytes of adult euploid and trisomic mice. This is in agreement with the chromosome assignments and dosage effects mentioned above.
Endogenous formation of prostanoids and the levels of long‐chain fatty acyl CoA derivatives in suspensive and adhesive cells from in vitro embryoid bodies of teratoma OTT 6050
Authors: Ohtsu Eiji , Hong Seong Su , Matsuzawa Taiju 
Published: May 2005

AbstractAttachment of the cell surface to a substratum may play a critical role in initiating some cellular developmental commitments and in sustaining differentiation of cells that have already been specialized. Embryoid bodies of teratoma OTT6050 were divided, on day 10 of initial culture, into myogenic adhesive cells which were already (at day 6) characterized by endogenous prostaglandin (PG)I2 formation and little‐specialized suspensive cells which formed only thromboxane (TX)B2 in the same culture system. Since at day 10 both cell types reached a stationary phase in which the nature of each cell was mature enough for the analyses with mass fragmentographic technique and gas chromatography‐ mass spectrometry (GCMS), the total levels of predominant long‐chain fatty acyl CoA (acyl CoA) derivatives could be measured comparatively as methyl esters after methanolysis. It was found as a result of major differentiation that adhesive cells had a rather low ratio of arachidonyl CoA to stearyl CoA, although adhesive cells accumulated a larger total amount of acyl CoA derivatives than that accumulated in suspensive cells.
The analysis of mammalian development using allelic isozyme variants
Authors: Kidder Gerald M. 
Published: May 2005

AbstractThe past decade has seen an explosion of interest in mammalian embryos. Techniques of molecular and genetic analysis coupled with advances in in vitro culture and experimental manipulation of mammalian embryos have provided important insights into mechanisms of embryogenesis. Many of these recent advances have been facilitated by the use of allelic isozyme variants as autonomous cell markers or representative gene products. Investigations aimed at exploring cell lineages and cell commitment, the timing and regulation of gene expression, X chromosome inactivation, and cell interactions have depended on the availability of appropriate isozyme variants. Results from such experiments are summarized here in order to demonstrate the usefulness of this approach and to stimulate its wider application in developmental biology.