bluuebunny/crossref_metadata_2025_split huggingface dataset:
DNA heterogeneity and genetic control of tumorigenesis in nicotiana tumorous and nontumorous genotypes
Authors: Durante Mauro , Geri Chiara , Buiatti Marcello , Baroncelli Sergio , Parenti Roberto , Ronchi Vittoria Nuti , Martini Guido , Grenci Fulvio Collina , Grisvard Janine , Guillé Etienne 
Published: May 2005

AbstractThe possible relevance of changes in amounts of highly repetitive DNA sequences for plant differentiation and dedifferentiation processes has been suggested in several cases. Data are lacking however on (1) the genetic control of these phenomena and (2) cause‐effect relationships between DNA amplification and specific ontogenetic patterns.The present study was carried out on a Nicotiana genetic system consisting of the tumorous amphidiploid N glauca X N langsdorffii, a nontumorous mutant of it, their F1, and a backcross to the tumorous parent. Backcross segregation ratios were shown to be compatible with a “single gene” hypothesis, the F1 plant being nontumorous but showing a low percentage of tumors induced by wounds, 6‐azauracil or X‐rays.In vitro studies of excised pith tissue grown on Linsmaier and Skoog medium for different periods of time showed the presence, confirmed by cytological analyses, of amplification of highly repetitive sequences only in the nontumorous stock, as judged by reassociation experiments in the first 24–96 hours of culture. CsCl analytical ultracentrifugation of those sequences showed the appearance in the same stock of a heavy DNA satellite (density = 1.721 gm/ml), whose presence was also confirmed by derivative melting curves.Amplification seemed to be essential for the initiation of cell division, which was completely inhibited in the nontumorous genotype and partially influenced in the F1 by incorporation during the critical period (24–96 hours of the primary explant) of 5‐bromo‐2′‐deoxy‐uridine.The results are discussed in terms of an hypothesis of an integrated gene‐controlled, hormone‐mediated regulatory system of cell proliferation involving changes in target repetitive DNA sequences.
Developmentally regulated gene expression in Artemia: Histone gene expression in newly hatched larvae
Authors: Bagshaw Joseph C. 
Published: May 2005

AbstractThe synthesis of histones and presence of histone mRNA sequences in embryos and larvae of the brine shrimp, Artemia, were investigated. Radiolabeling of proteins synthesized in vivo followed by electrophoretic and fluorographic analysis confirmed the prediction that histone synthesis is coordinated with the wave of DNA replication in newly hatched larvae. No histone synthesis occurs during development of encysted embryos. Hybridization of cloned Artemia histone gene DNA to total cell RNA indicated that dormant encysted embryos do not contain “masked” messenger RNA.
The intracellular ratio of the membrane to the secreted form of immunoglobulin M heavy chain is a measure of the developmental stage of B cell lymphomas
Authors: Sibley Carol H. , Mar Holly A. , Mains Paul E. 
Published: May 2005

AbstractTumors of B lymphocyte origin have been used as models for normal B cells “frozen” at particular stages of their development. Surface properties, amount, and intracellular location of immunoglobulin and the synthesis of J chain have all been used as indicators of developmental stages. Each requires special techniques or yields data that are difficult to compare from one experiment to the next. For these reasons, we have developed a metric for B cell development that is simple to perform and allows quick quantitative comparisons of cell lines.It has recently been established that the membrane (μm) and secreted (μs) forms of the IgM heavy chain differ at their extreme carboxy termini. The two proteins differ slightly in size and are easily distinguished when they are compared without their carbohydrate on sodium dodecyl sulfate (SDS) polyacrylamide gels. We have examined four mouse tumors derived from the B lymphocyte lineage whose phenotypes resemble late pre‐B cells (internal μ only; uninduced 70Z/3), small B lymphocytes (high levels of surface IgM; LPS‐induced 70Z/3, WEHI 231), lymphoblasts (both membrane and secreted IgM; WEHI 279.1), and plasma cells (copious IgM secretion; MOPC 104E). Despite the fact the 70Z/3 and WEHI 231 secrete no detectable IgM, all of the tumors synthesize at least intracellular forms of both μm and μs. The proportion of μm is stable and is characteristic of each tumor. The 70Z/3 cells and WEHI 231 cells synthesize about 75% of their total μ as μm; WEHI 279.1 cells synthesize about 30% and MOPC 104E cells about 5% of their total μ as μm. The population of LPS‐stimulated B lymphocytes shows a similar progression during its differentiation. The proportion of μm correlates with other developmentally regulated parameters (Fc receptor, Ia and plasma cell antigen levels, and J chain) and can be used as a simple metric for comparison with developing B lymphocytes and determination of the developmental stage of a B cell tumor.
Ovarian pathologies generated by various alleles of the otu locus in Drosophila melanogaster
Authors: King Robert C. , Riley Shawn F. 
Published: May 2005

AbstractA comparative cytological study was made of oogenesis in flies carrying various mutant alleles of the female sterile gene otu. It resides at 22.7 on the genetic map and within subdivision 7F of the cytological map of the X‐chromosome. Each of the five ethyl methane sulfonate‐induced mutations observed falls into one of three classes. In class 1, most mutant ovarioles lack germ cells; in class 2, most mutant ovarioles contain tumorous chambers; and in class 3 mutants, chambers occur that possess defective oocytes. The otu2 allele belongs to class 1; otu1 to class 2; and otu3, otu4, and otu5 to class 3. The mutations have no effects upon female viability or upon the viability and fertility of hemizygous males. Heterozygous females are fertile and have cytologically normal ovaries. In otu5 homozygotes, all ovarioles contain egg chambers, but oogenesis is prematurely terminated to produce a pseudo‐stage 12 oocyte. Ovarioles from otu3 and from otu4 homozygotes contain both ovarian tumors and oocytes. Pseudonurse cells (PNC), which are cystocytes that have stopped dividing and have entered the nurse cell mode of development, are also abundant. PNCs contain polytene chromosomes. Since the homologs are paired, each nucleus has the haploid number of chromosomes. In chambers lacking an oocyte, the number of PNCs is less than the normal number of nurse cells. In chambers containing an oocyte, the number of accompanying nurse cells may be 15, or above or below normal. In vitellogenic chambers, the chromosomes in the nurse cells connected directly to the oocyte are more expanded than those in more distant nurse cells. The KA14 deficiency lacks the plus allele of otu. KA14 heterozygotes are fertile and have cytologically normal ovaries. When females carry KA14 and otu1, otu3, otu4, or otu5, 80% of their ovarioles are agametic. When females carry otu2 and one of the other mutant alleles, the ovarioles proceed further in development. So otu2 produces a product that has a beneficial effect on the test allele. When two different otu alleles are combined in a single fly, the phenotype of the hybrid ovary usually most resembles that of the ovary homozygous for the “stronger” allele (the otu mutant that allows oogenesis to proceed farthest). The results indicate that the product of the otu+ locus functions at least three different times during oogenesis; first to permit oogonia to proliferate, second to control the division and differentiation of germarial cystocytes, and third to facilitate the normal growth of the ooplasm. The gene product appears to be required in higher concentrations at each developmental period. The lesions produced by the mutations are thought to interfere with the stability or functioning of the gene product, and the ovarian phenotype produced by a given genotype depends upon the concentration of functional gene product available to the germ cells.
Homoeosis in Drosophila: Evidence for a maternal effect of the polycomb locus
Authors: Denell R. E. 
Published: May 2005

AbstractWhen heterozygous, dominant mutant alleles of the Polycomb locus are associated with a variety of adult homoeotic effects. Zygotes homozygous for these alleles die as late embryos showing homoeotic transformation of head, thoracic, and abdominal segments. This study shows that embryos homozygous forPc3are more extreme than those homozygous forPc1orPc2. Moreover,Pc1/Pc3heterozygotes are more extensively transformed if their mothers werePc3/ + than if they werePc1/ +; this effect does not depend on zygotic genetic background and must be maternal in nature. Embryos homozygous forPc3are less extreme if they arise fromPc3/ + / + than fromPc3/ + mothers. These results strongly suggest that the Polycomb locus acts maternally as well as zygotically to affect early determinative decisions.
In vivo radiolabeling and turnover of sn‐glycerol‐3‐phosphate dehydrogenase in Drosophila melanogaster: Gene dosage effects
Authors: Wilkins Joseph R. , Shaffer Jacquelin B. , Bewley Glenn C. 
Published: May 2005

AbstractIn vivo radiolabeling of Drosophila melanogaster sn‐glycerol‐3‐phosphate dehydrogenase (E.C. 1.1.1.8; GPDH) has been accomplished by microinjection of 3H‐leucine into anesthetized flies. Comigration of immunoprecipitated radiolabeled GPDH with purified 14C‐labeled GPDH‐1 in SDS polyacrylamide disc gels has established the monospecificity of our immunoprecipitation technique. Short‐term uptake experiments have demonstrated that maximum radiolabel incorporation of total TCA precipitable protein and immunoprecipitable GPDH‐1 occurs within 4 hours postinjection, with GPDH‐1 accounting for approximately 1% of the total radiolabeled TCA precipitable protein. In order to develop the parameters for turnover studies of GPDH in Drosophila, a comparative analysis of the rates of synthesis and degradation of GPDH‐1 in flies bearing two and three doses of the structural gene have been conducted by the construction of adult flies aneuploid and euploid for the cytogenetic region 25F‐26B on the left arm of chromosome II. Short‐term uptake studies have demonstrated that the rate of GPDH‐1 synthesis in the three‐dose flies is approximately 1.58 times that found in the two‐dose euploid flies. This value is in close agreement with data obtained for steady‐state levels of CRM by rocket immunoelectrophoresis. In contrast, longterm pulse‐chase experiments have revealed that rates of GPDH‐1 degradation in these aneumploid and euploid flies appear to be identical. These data suggest that the rate of GPDH‐1 synthesis in Drosophila is primarily regulated by a tightly linked cis‐acting element which appears to act autonomously with respect to gene copy number as well as steady‐state GPDH protein levels.
Lethal bithorax complex mutations of Drosophila melanogaster show no germ line maternal effects
Authors: Kerridge Stephen , Dura Jean‐Maurice 
Published: May 2005

AbstractThree Ultrabithorax (Ubx) alleles and three different deficiencies of the bithorax complex (BX‐C) of Drosophila melanogaster have been tested for maternal effects in the germ line. The dominant female sterile technique was used. The Ubx alleles and a deletion of the abdominal region of the BX‐C are homozygous viable in germ line clones and show no maternal effects. Two deletions which lack the proximal portion of the BX‐C are lethal in the female germ line indicating either that these deficiencies lack genes apart from the BX‐C that are necessary for fertility or that there are BX‐C genes that are essential for normal maternal germ line function. The significance of the bias in the isolation of only zygotic mutations at the BX‐C are discussed with respect to these results.
Chitin biosynthesis during pupal development of Drosophila melanogaster and the effect of the lethalcryptocephal mutation
Authors: Sparrow John C. , Chadfield Colin G. 
Published: May 2005

AbstractEstimation of chitin deposition in the pupal and adult cuticles of adult Drosophila melanogaster during the pupal period is described. The timing of the periods of chitin deposition is compared with that deduced by previous workers using electron microscopy. The hypothesis that lethalcryptocephal mutant homozygotes are unable to evert their cephalic complexes at pupation because of excess chitin deposition is examined. The data obtained show no evidence that the mutation has any effect on chitin deposition.
Isolation and characterization of cAMP unresponsive (frigid) aggregation‐deficient mutants of Dictyostelium discoideum
Authors: Coukell M. Barrie , Lappano Sergio , Cameron Anne M. 
Published: May 2005

AbstractTo find mutants of Dictyostelium discoideum that are unable to respond to exogenous cAMP signals (frigid mutants), amoebae of 218 independent aggregation‐deficient mutants were treated in suspension with artificial pulses of cAMP and screened for the capacity to form EDTA‐resistant cohesion sites. Eleven frigid mutants were identified and further characterized. Using parasexual genetic techniques, these strains were assigned to five complementation groups (fgdA‐E) and the fgd loci were mapped in three linkage groups: fgdA and D in group II, fgdC in group III, and fgdB and E in group VII. Biochemical and physiological experiments with these strains indicated that fgd mutants are of two general types. When starved, strains in groups fgdB, D, and E failed to produce detectable levels of membrane‐associated cAMP phosphodiesterase, surface cAMP receptors, or extracellular phosphodiesterase inhibitor, and the cells continued to respond chemotactically to folate. Thus, these strains are probably arrested in the vegetative phase or very early in development. In contrast, strains in groups fgdA and C produced low levels of cAMP receptors and secreted phosphodiesterase inhibitor. Moreover, after starvation, some of these mutants elicited a weak chemotactic response to cAMP. Therefore, unlike the former group of mutants, these strains appear to initiate development when starved, but the process is blocked at an early stage.
DNA polymerase activity in developmental stages of Drosophila melanogaster
Authors: Dusenbery Ruth L. , Smith P. Dennis 
Published: May 2005

AbstractAn assay procedure was developed that allowed the first reproducible measurement of DNA polymerase activity in all developmental stages of Drosophila melanogaster. Evidence is presented that the same enzymatic species is present in extracts of embryos, pupae, and adults of both sexes and that this activity has many properties similar to vertebrate α‐polymerases. Polymerase activity per individual is low in embryos and rises steadily through larval instars, reaches a peak in early pupae, declines through the late pupal period, and remains low in newly eclosed adults of both sexes. A dramatic increase is observed in adult females as mature oocytes are formed. This pattern of enzyme activity is completely coincident with changes in DNA levels during development, and suggests that the Drosophila enzyme, like vertebrate α‐polymerases, functions in cellular DNA replication. Two mutagen‐sensitive mutants, deficient in both replication on undamaged templates and postreplication repair, were found to have normal levels of this α‐polymerase activity. Our results suggest that a single enzymatic species of α‐polymerase holoenzyme exists in Drosophila and is common to all developmental stages of this organism.
Lethal(1)fibrillardysgenesis (I(1)fdg), a mutation affecting muscle development in the embryo of Drosophila melanogaster
Authors: Newman Samuel M. , Wright Theodore R. F. 
Published: May 2005

AbstractThe I(1)fdg mutation demonstrates two separate phases of lethality, depending on developmental conditions. At 32–33°C, an embryonic lethality is expressed whereas at lower temperatures a larval‐pupal lethality is observed. This larval‐pupal lethality characteristically produces noncondensed, curved puparia, and since the contraction of the pupa depends on strong muscular contraction, this phase of lethality implicates some involvement of abnormal musculature. The embryonic expression of I(1)fdg at 32–33°C is the subject of this study. In these embryos, which are alive but immobile (incapable of hatching), the fibrillar organization and fiber morphology of the somatic musculature varies from being apparently normal to being grossly abnormal. While the abnormalities appear as unusual distributions of fiber organelles, abnormal convolutions of the muscle fibers, and disorganizations of fibrillar components, it seems most probable that the underlying defect ultimately responsible resides in some system essential for Z body alignment and sarcomere formation. Accompanying the embryonic lethality, certain abnormalities in midgut development are observed which at present do not appear to be related to the defects observed in the somatic muscle.
Developmental and tissue‐specific control of catalase expression in Drosophila melanogaster: Correlations with rates of enzyme synthesis and degradation
Authors: Bewley Glenn C. , Nahmias Joseph A. , Cook Julia L. 
Published: May 2005

AbstractThe ontogenetic and tissue‐specific expression of catalase (E.C. 1.11.1.6) has been determined in a wild type strain of Drosophila melanogaster derived from a natural population. Two distinct peaks of activity are observed during development with the first peak occurring in late third instar larvae just prior to puparium formation, and the second and larger of the two peaks occurring during metamorphosis. These peaks of catalase activity are coincident with the two major peaks of ecdysone titer. Of the tissues assayed, larval malpighian tubules, gut, and fat body demonstrated the highest specific activities. Adult abdomen exhibited a two‐ to three‐fold higher specific activity than either head or thorax. Of the abdominal tissues assayed, malpighian tubules and abdominal wall had the highest specific activities. Malpighian tubules were the only sexually dimorphic tissue with respect to catalase activity and are apparently largely responsible for an overall increase observed in female abdominal activity. Catalase‐specific CRM levels parallel the enzyme activity levels indicating that these tissue‐specific activity differences reflect differences in the rate of accumulation of catalase molecules.Turnover studies employing the catalase inhibitor 3‐amino‐1,2,4‐triazole were conducted on head, thorax, and abdomen of male adult flies. Rates of catalase degradation were similar in the three body segments with a slightly higher rate in abdominal tissue. Therefore the different steady state levels observed largely reflect different rates of catalase synthesis.
Homoeosis in Drosophila: Maternal effect of the enhancer of Polycomb locus and its interaction with Polycomb and related loci
Authors: Sato Takashi , Hayes Pliny H. , Denell Robin E. 
Published: May 2005

AbstractA mutation or deficiency of the Enhancer of Polycomb (E(Pc)) locus acts as a dominant enhancer of the adult mutant phenotypes of a group of similar homoeotic loci (Polycomb, Polycomblike, extra sex comb, and lethal(4)29). The E(Pc) mutation has a recessive lethal effect, and homo‐ and hemizygotes die as late embryos or larvae which appear cuticularly normal. E(Pc) also acts as a dominant enhancer of the embryonic homoeotic syndromes associated with Polycomb. Polycomblike, and lethal(4)29 mutations: its effect on the extra sex comb syndrome has not been effectively evaluated. At least for the interaction with Polycomb mutations, evidence is presented that the Enhancer of Polycomb locus has a maternal as well as a zygotic effect, and that its effect on Polycomb expression is not at the level of transcription. We suggest that the Enhancer of Polycomb locus acts specifically to regulate the activities of this set of homoeotic loci, and that E(Pc) recessive lethality results from noncuticular homoeotic defects which arise as a consequence of their reduced activity. In the context of this hypothesis, no present data allow us to distinguish whether Enhancer of Polycomb is a nonhomoeotic locus regulating the function(s) of Polycomb and related genes or is itself a homoeotic locus.
A mutation in Drosophila that appears to accelerate aging
Authors: Leffelaar David , Grigliatti Thomas A. 
Published: May 2005

AbstractThe question as to the role that genes play in determining life‐span is essentially unresolved. Although it is well documented that genotype influences longevity, this is no way demonstrates that life‐span is genetically determined. In the present study we examine five temperature‐sensitive mutations for their effect on the aging process. At the permissive temperature (22°C ), the longevity of each mutant strain is comparable to that of wild type. However, at the restrictive temperature (29°C ) the life‐span of these mutants is severely curtailed. Using behavior loss as a landmark of adult physiological age, we examined each of these strains for its pattern of behavior loss relative to longevity, and compared each to a wild‐type strain. In four of the mutations the pattern of behavior loss relative to longevity was severely altered at one or both temperatures. However, one strain, adl‐16tsl displayed a pattern of behavior loss that was indistinguishable from wild type at both 22°C and 29°C. At 29°C not only was the longevity decreased, the pattern of behavior loss was also compressed into a shorter time period. The compression of the pattern of behavior loss was proportional to the reduction in life‐span. Thus it appears that this mutation, adl‐16tsl, may accelerate the normal aging process when placed at 29°C. The potential utility of these types of mutants for studying the aging process is discussed.
On the evolutionary relationships of Drosophila melanogaster
Authors: Ashburner Michael , Bodmer Mark , Lemeunier Francoise 
Published: May 2005

AbstractThe gene coding for alcohol dehydrogenase (Adh) in Drosophila melanogaster maps to 2:50.1 on chromosome arm 2L. It is expressed in both larvae and adults, coding for an abundant enzyme that plays a role in the detoxification of primary and secondary alcohols. In larvae the gene is most abundantly expressed in the fat body and gut. We have recently shown [49] that the major Adh transcripts differ in larvae and adults, the major adult transcript being initiated from a promotor several hundred pairs 5′ to the promotor from which the major larval transcript is initiated. However the coding region of the “larval and adult” mRNA are identical. We discuss recent studies of the transcriptional organization Adh and compare the structure of this gene in D. melanogaster with that in other species of Drosophila. The entire Adh gene and its surrounds has been sequenced from four species of Drosophila [45,48]. This data has been used not only for the study of phylogenetic relationships, but also of the types of sequence variation seen between species. The constraints on mutational change, especially with respect to codons, will be discussed.
The role of mRNA structure in the regulation of protein synthesis: Implications for studies of development
Authors: Vournakis John N. , Vary Calvin P. H. 
Published: May 2005

AbstractA method is described for the experimental determination of the secondary structure of RNA using enzymatic cleavage data coupled with computer analysis. The structure‐specific enzymes S1 nuclease and cobra venom ribonuclease are used to locate nonpaired and basepaired nucleotides, respectively. Computer techniques that utilize the enzymatic susceptibility information to generate a minimum free‐energy structure are used to obtain secondary structure models. A second method, using acrylamide‐agarose gel electrophoresis, is described for the determination of the relative protein synthesis initiation rates of endlabeled eukaryotic mRNAs. These methods are applied to the rabbit globin mRNAs as an example of a general approach for relating mRNA structure and function. A discussion of the role of messenger RNA structure in the regulation of translation is included with an emphasis on studies of development.