bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat shock induced proteins in plant cells
Authors: Barnett Thomas , Altschuler Mitchell , McDaniel Carl N. , Mascarenhas Joseph P. 
Published: May 2005

AbstractTobacco (Nicotiana tabacum) and soybean (Glycine max) tissue culture cells were exposed to a heat shock and protein synthesis studied by SDS‐polyacrylamide gel electrophoresis after labeling with radioactive amino acids. A new pattern of protein synthesis is observed in heat‐shocked cells compared to that in control cells. About 12 protein bands, some newly appearing, others synthesized in greatly increased quantities in heat‐shock cells, are seen. Several of the heat‐shock proteins (HSPs) in both tobacco and soybean are similar in size. One of the HSPs in soybean (76K) shares peptide homology with its presumptive 25°C counterpart, indicating that the synthesis of at least some HSPs may not be due to activation of new genes. The optimum temperature for maximal induction of most HSPs is 39–40°C. Total protein synthesis decreases as heat‐shock temperature is increased and is barely detectable at 45°C. The heat‐shock response is maintained for a relatively short time in tobacco cells. After 3 hr at 39°C, a decrease is seen in the synthesis of the HSPs, and after 4 hr practically no HSPs are synthesized. After exposure to 39°C for 1 hr, followed by a return of tobacco cells to 26°C, recovery to the control pattern of synthesis requires greater than 6 hours. These results indicate that cells of flowering plants exhibit a heat‐shock response similar to that observed in animal cells.
Restriction of PGK‐B to spermatogenic cells: Evidence from experimentally cryptorchid mice
Authors: Rudolph Natalie S. , VandeBerg John L. 
Published: May 2005

AbstractThe hypothesis that PGK‐B, like LDH‐C4, is restricted to spermatogenic cells was explored by examining isozyme patterns in testes from mice depleted of germinal cells by surgical cryptorchism. In experimentally cryptorchized C57BL/10Sn males, decline in PGK‐B activity paralleled decline in LDH‐C4 activity and was correlated with degeneration of spermatocytes, spermatids, and spermatozoa. Trace amounts of these sperm isozymes found in cryptorchid testes after the depletion of maturing germ cells probably came from degenerated spermatids and spermatocytes and not from somatic testicular cells.
Recombinant DNA analysis indicates that the multiple chromosomes of maize mitochondria contain different sequences
Authors: Spruill W. M. , Levings C. S. , Sederoff R. R. 
Published: May 2005

AbstractTwenty‐eight Bam H 1 restriction fragments were isolated from normal mitochondrial DNA of maize by recombinant DNA techniques to investigate the organization of the mitochondrial genome. Each cloned fragment was tested by molecular hybridization against a Bam digest of total mitochondrial DNA. Using Southern transfers, we identified the normal fragment of origin for d each clone. Twenty‐three of the tested clones hybridized only to the fragment from which the clone was derived. In five cases, labeling of an additional band indicated some sequence repetition in the mitochondrial genome. Four clones from normal mitochondrial DNA were found which share sequences with the plasmid‐like DNAs, S‐1 and S‐2, found in S male sterile cytoplasm. The total sequence complexity of the clones tested is 121×106 d (daltons), which approximates two thirds of the total mitochondrial genome (estimated at 183×106 d).Most fragments do not share homology with other fragments, and the total length of unique fragments exceeds that of the largest circular molecules observed. Therefore, the different size classes of circular molecules most likely represent genetically discrete chromosomes in a complex organelle genome. The variable abundance of different mitochondrial chromosomes is of special interest because it represents an unusual mechanism for the control of gene expression by regulation of gene copy number. This mechanism may play an important role in metabolism or biogenesis of mitochondria in the development of higher plants.
The expression of β‐galactosidase during preimplantation mouse embryogenesis
Authors: Esworthy Steve , Chapman Verne M. 
Published: May 2005

AbstractLysosomal acid hydrolase expression during preimplantation mouse embryogenesis has proved useful in estimating when mRNA transcription commences during this period. Previous work from this laboratory has shown that α‐galactosidase and β‐glucuronidase undergo 50‐ to 100‐fold increases in activity between the two‐cell stage and the blastocyst stage [1, 2]. Here we show that β‐galactosidase activity levels undergo a similar change. We also demonstrate that mouse strains with the Bgl‐sh allele produce cleavage stage embryos with 2–4‐fold higher activity levels than strains with the Bgl‐sd allele. Bgl has been shown to control β‐galactosidase levels in adult mouse tissues [3]. Unfertilized egg β‐galactosidase levels are also regulated by Bgl, but loci distant from Bgl modify egg expression. The distant sites are not observed to act during cleavage. Hybrid embryos (Bgl‐sd/h) show intermediate activity levels to the parental types. The timing of the deviation of hybrid embryo β‐galactosidase activity levels from maternal‐type activity levels is used to estimate when transcription of genes governing β‐galactosidase expression occurs.
Genetic analysis of mating type differentiation in Paramecium tetraurelia. III. A mutation restricted to mating type E and affecting the determination of mating type
Authors: Brygoo Yves , Keller A. M. 
Published: May 2005

AbstractIn P. tetraurelia each cell is determined to express only one of the two complementary mating types, O and E. This determination is under cytoplasmic control and seems to be achieved only by the commitment or noncommitment to the expression of mating type E. All the previously known mutations affecting the differentiation of mating type prevent the expression of the E mating type (O‐restricted mutations) without affecting the determination process. An E‐restricted mutation was obtained: mtFE. Its phenotypic properties indicate that the mutation affects the determination process itself. When an O cell becomes mtFE/mtFE it acquires the E mating type and an E‐determining cytoplasm. We propose that this constitutive determination for the E mating type is due to the inefficiency of a factor which is normally active in an O cell. This factor would act like a repressor and stabilize the E functions under an inactive state.
A mutation with pleiotropic effects on macronuclearly differentiated functions in Paramecium tetraurelia
Authors: Brygoo Yves , Keller A. M. 
Published: May 2005

AbstractThe mtFE mutation isolated in Paramecium tetraurelia affects mating type differentiation, trichocyst excretion, and viability. Its effect on mating type has already been shown to correspond to a restriction to the E mating type interpreted by an inefficiency of nuclear O‐determining factors. In this paper we study the other two phenotypic characteristics whose hereditary transmission displays two unusual features. (1) In crosses between a wild‐type strain and the mutant strain, the mutant characteristics do not reappear in F2 in the wild‐type cytoplasmic lineage but only in F3 after the homozygous clones have undergone an additional nuclear reorganization. (2) Some F2 wild‐type clones, in the mutant cytoplasmic lineage, retain some of the phenotypic characteristics of the mutant. We propose that the mtF gene product plays a role in the control of several macronuclearly differentiated functions.
A biochemical analysis of cartilage proteoglycan in the avian mutant micromelia‐abbott
Authors: Quintner Mitchell I. , Goetinck Paul F. 
Published: May 2005

AbstractEmbryos homozygous for the recessive lethal gene, micromelia‐Abbott, develop a severe form of micromelia, a parrot‐like beak, and hemorrhagic skin. Feather development is also retarded. The reduction in length of the long bones of the leg can be traced to their cartilaginous stage Quantitative analysis of sulfated proteoglycan (PGS), a major macromolecular component of cartilage matrix, reveals that mutant tibiae, femora, and sterna contain significantly less uronic acid per μg of DNA than normal rudiments, indicating reduced accumulation of PGS in the mutant. Incorporation of radioactive precursors into cartilage PGS is severely reduced in relatively early developmental stages of a particular organ, but this reduction becomes less severe in cartilage taken from the same rudiment at a later developmental stage. Analysis of the sedimentation rate of PGS in sucrose gradients reveals no difference between normal and mutant in all cartilaginous types at all ages. These results suggest that the quantity and not the quality of PGS is affected in this mutant. The observation that the addition of para‐nitrophenyl‐β‐D‐xyloside to the culture medium can stimulate glycosaminoglycan synthesis to normal levels is interpreted to mean that the reduced levels of PGS may be the result of a reduced availability of the xylosylated protein backbone for PGS.
Haltere determination and mutations at the bithorax locus
Authors: Adler Paul N. 
Published: May 2005

AbstractMutations at the bithorax locus transform anterior haltere tissue into anterior wing. These transformations could in principle be due to the mutations altering either the expression or cell heredity functions of determination. I have studied two alleles of the bithorax locus bx3 and bx34e using disc culture techniques and found that both produce their transformations by altering the expression of the determined state. I have also found that the expression of the temperature‐sensitive allele, bx34e, can be altered by temperature shifts during the culture period. Evidence has been obtained that suggests that such changes in expression do not require growth or cell division.
Influence of homoeotic genes on the aldehyde oxidase pattern in imaginal discs of Drosophila melanogaster
Authors: Sprey Th. E. , Segal D. , Sprey‐Pieters H. E. , Kuhn D. T. 
Published: May 2005

AbstractIn a study of the regulation of enzyme patterns in imaginal discs the aldehyde oxidase pattern was determined for some homoeotic mutations of D. melanogaster. Earlier indications that suggested that this pattern follows the determinitive state of compartments within imaginal discs were confirmed by the aldehyde oxidase (AO) pattern of both the wing and haltere discs from en1; bx3, en1; pbx, and en1; bx3 pbx larvae and the antennal discs from Antp73b and ssa larvae.We additionally analyzed whether AO activity depended on the determinative state of an entire compartment or was expressed autonomously in clones. Homozygous engrailed clones were induced by mitotic recombination. From the AO clones found in normally negative areas of the posterior compartment it was concluded that enzyme activity depended upon the determinative state of the cells and was not a function of the compartment as a whole.The results are described with reference to a scheme in which compartmental and subcompartmental selector genes are thought to determine a binary code on which AO patterns depend.
Genetic regulation of alcohol dehydrogenase C2 in the mouse. Developmental consequences of the temporal locus (Adh‐3t) and positioning of Adh‐3 on chromosome 3
Authors: Holmes Roger S. , Andrews Sandra J. , Beechey Colin V. 
Published: May 2005

AbstractThe tissue specificity of a proposed cis‐acting temporal locus (Adh‐3t), which regulates alcohol dehydrogenase C2 (ADH‐C2) activity in mouse reproductive tissue extracts, has been examined in C5 7BL/6J, SM/J, F1 (SM/J × C5 7BL/6J) mice as well as in progeny of an (F1 [SM/J × C5 7BL/6J] × C5 7BL/6J) back‐cross. Electrophoretic variants for ADH‐C2, previously used to localize the gene (Adh‐3) encoding this enzyme on chromosome 3, enabled the relative parental contributions to ADH‐C2 phenotype in F1 and backcross mouse tissues to be determined. These analyses demonstrated that (1) stomach, kidney, lung, adrenals, seminal vesicles, epididymis, uterus, and ovary ADH‐C2 is encoded by a single locus (Adh‐3); Adh‐3t is differentially active in various tissues, eg, lung exhibits no apparent activity whereas the temporal locus is fully active in seminal vesicles; (3) Adh‐3t is probably differentically active in different cells of some tissues, eg, adrenals. Specific activity profiles of stomach and epididymal ADH‐C2 during the neonatal development of C5 7BL/6J, SM/J, and F1 (SM/J × C5 7BL/6J) male mice supported the proposal for a cis‐acting temporal locus for this enzyme. Genetic analyses examining segregation of Adh‐3 and Adh‐3t among backcross progeny suggested that these are distinct but closely linked loci, since one recombinant among 256 progeny was observed. Linkage data of Adh‐3 with Va (varitint‐waddler) and de (droopy ear) was also obtained, which suggested that Adh‐3 is localized on chromosome 3 between Va and de.
An X chromosome locus in Drosophila melanogaster that enhances survival of the triplo‐lethal genotype, Dp‐(Tpl)
Authors: Roehrdanz Richard L. , Lucchesi John C. 
Published: May 2005

AbstractOnly a single locus (Tpl) is known in the Drosophila melanogaster genome that leads to early lethality when present as a heterozygous duplication (three doses) or deficiency (one dose). We report the recovery of third instar larvae (and of occasional adults) carrying a duplication for the triplo‐lethal locus, Dp(Tpl). Karyotype analysis of the larvae showed that the individuals surviving were almost entirely 3X;2A metafemales. We examined the question of whether the entire X or a single X locus was a major factor permitting survival. X‐Y translocations were used to produce females hyperploid for different portions of the X and carrying Dp(Tpl). Analysis of metaphase chromosomes by quinacrine fluorescence pattern indicates that the X chromosome region between 6D and 7DE must be present in an extra copy to enhance the survival of Tpl duplication‐bearing females. Another type of experiment suggests that it is the region between 7C and 7DE which is essential.
Visualization of the F9 antigen on sperm from normal and T/t‐complex mutants by immunoscanning electron microscopy
Authors: Ben‐Shaul Yehuda , Babiarz Bruce , Bennett Dorothea 
Published: May 2005

AbstractThe antigens defined by conventional syngeneic antiserum against F9 embryonal carcinoma cells were localized on mature sperm using immunolabeling and scanning electron microscopy. Labeling patterns were compared for normal (+ / +) mice and mice bearing recessive t‐haplotypes. The results showed that antigens detected by intact anti‐F9 antiserum are expressed similarly in all genotypes, except for sperm from mice bearing the t12‐haplotype where the frequency of labeled cells was reduced. Labeling with the IgM fraction of anti‐F9 antiserum was lower on sperm from all t‐genotypes examined, with sperm from + /t12 males showing the most marked reduction. In all cases, the labeling patterns were similar, and included a labeling of the whole sperm head with complete anti‐F9 antiserum and a restriction of the label to the postacrosomal region when the IgM fraction was used.
Probable somatic DNA rearrangements in mating type determination in Tetrahymena thermophila: A review and a model
Authors: Orias Eduardo 
Published: May 2005

AbstractExperimental data on mating type determination in T. thermophila, collected by Nanney, Allen, and their collaborators over a period of 25 years, are reinterpreted in the light of our current understanding of macronuclear genetics. A strong case is developed supporting the idea that mating type determination involves the developmental alteration of somatic DNA that occurs regularly in developing macronuclei in conjugating pairs. A. testable DNA deletion/splicing model is developed that although based on a few simple, plausible assumptions, explains the observations remarkably well. The model is in (at least) superficial analogy to the mechanism that must be involved to explain the somatic differentiation and alteration of DNA sequences that ultimately constitute an expressed vertebrate immunoglobulin gene. Because of the genetic, biochemical, and micromanipulative versatility of Tetrahymena, it may well turn out to be a uniquely suitable microbial eukaryotic experimental system for the study of developmental alterations of somatic DNA.
The genetics of dopa decarboxylase in Drosophila melanogaster. III. Effects of a temperature sensitive dopa decarboxylase deficient mutation on female fertility
Authors: Wright Theodore R. F. , Steward Ruth , Bentley Karen W. , Adler Paul N. 
Published: May 2005

AbstractThe mutation Ddcts1 effects female sterility when homozygous, hemizygous, or heterozygous over a series of Ddc null alleles (Ddcx) indicating that some aspect of Ddc gene function is necessary for female fertility. Ovary transplant experiments demonstrate that the female sterility phenotype is ovary autonomous. Two to 3% of the total DDC activity measurable in newly hatched females is localized in their previtellogenic ovaries. The degree to which females heterozygous for Ddcts1 over different Ddc null alleles are fertile at 22°C reflects a continuous spectrum of allelic complementation similar to that observed for the effects of these genotypes on viability at 30°C. Fertility of all the Ddcts1/Ddcx females tested is significantly depressed at 30 vis‐a‐vis 22°C providing evidence that it is the DDC enzyme activity itself which is required for female fertility. Ddcts1/Ddcts1 homozygous and Ddcts1/Df hemizygous females are nonconditionally, completely sterile at 18, 20, 22, 25, and 30°C. Although all homo‐ and hemizygous females do lay some eggs, no evidence of embryogenesis or fertilization has ever been detected. The absolute, nonconditional sterility of Ddcts1 homo‐ and hemizygous females stands in stark contrast to the conventional temperature dependent effects of these same genotypes on viability and to the temperature sensitive effects of Ddcts1/Ddcx heterozygous females on both fertility and viability. Reasons for these tissue‐specific and genotypic differences are discussed.
Developmental modulation of protein synthesis in Drosophila primary embryonic cell cultures
Authors: Buzin Carolyn H. , Seecof Robert L. 
Published: May 2005

AbstractThe patterns of proteins synthesized during embryonic development in Drosophila melanogaster have been examined by two‐dimensional gel electrophoresis. Primary cell cultures prepared from donor embryos synchronized to ± 1 hr were labeled with [35S]methionine at 5, 11.5, 14.5, and 26 hr after oviposition. Of approximately 400 to 500 proteins detected, the synthesis of about 50 is developmentally modulated. The greatest number of changes in the synthesis of stage‐specific proteins occurs at 11.5 and 14.5 hr after oviposition, periods just prior to and during the times of the greatest overt morphological and biochemical changes. At 11.5 hr, 35 stage‐specific proteins are synthesized, including 19 that are not present at the previous stage examined. At 14.5 hr, 34 stage‐specific proteins can be detected, including 11 newly synthesized proteins. However, 12 proteins from the previous stage are no longer synthesized. At the completion of embryonic differentiation, at 26 hr, no new proteins are synthesized and the synthesis of many present in earlier stages has decreased or stopped. Comparison of patterns of embryonic proteins to those synthesized by two Drosophila continuous cell lines reveals that the majority of proteins are common to all. However, only about 40% of the embryonic stage‐specific proteins are present in either cell line. In addition, there are several proteins unique to each cell line that are not observed in any of the embryonic stages.
Revertants of selfing (gad) mutants in Physarum polycephalum
Authors: Anderson Roger W. , Holt Charles E. 
Published: May 2005

AbstractThe conversion of the uninucleate amoebal form of Physarum polycephalum to the multi‐nucleate plasmodial form is under the control of a genetic region which contains matA (or mt), a determinant of mating specificity. The region is the site of most gad mutations, which give amoebae the ability to produce plasmodia in clones without mating (ie, to self). In the present study, nonselfing revertants were isolated from two matA2‐derived gad mutants and two matA3‐derived gad mutants. Some revertants were found to have regained exactly, or nearly, the same phenotype as the original matA2 or matA3 strain. Others expressed new mating types, having gained the ability to mate with strains of the parental matA type. The results are compatible with a model in which new mating types arise from forward mutations (gad) and back mutations (npf or no plasmodium formation) occurring successively in a single gene, matA.
Non‐random X‐chromosome expression early in mouse development
Authors: Papaioannou Virginia E. , West John D. , Bücher Theodor , Linke Ingrid M. 
Published: May 2005

AbstractWe have used a sensitive electrophoretic technique for estimating the activity, or ratio, of two allozymes of the X‐chromosome‐linked enzyme phosphoglycerate kinase (PGK‐1), in order to investigate the randomness of X‐chromosome expression in the derivatives of the three primary cell lineages of the early mouse conceptus. The maternally derived Pgk‐1 allele is preferentially expressed in the derivatives of the primitive endoderm and trophectoderm lineages at 6 1/2 days post coitum in Pgk‐1a/Pgk‐1b heterozygous conceptuses, and in the one informative 5 1/2‐day heterozygous conceptus analysed. This evidence for preferential expression of the maternally derived X chromosome (Xm), so soon after the time of X‐chromosome inactivation, favors the possibility that the preferential expression of Xm is a consequence of primary non‐random X‐chromosome inactivation, rather than a secondary selection phenomenon. The majority of embryos analysed at 4 1/2 and 5 1/2 days pc produced only a single PGK‐1 band, corresponding to the allozyme produced by the Pgk‐1 allele on Xm, although 50% of these embryos should have been heterozygous females. Possible explanations are discussed.
Organization of mitochondrial DNA in normal and texas male sterile cytoplasms of maize
Authors: Spruill W. M. , Levings C. S. , Sederoff R. R. 
Published: May 2005

AbstractRecombinant DNA and hybridization techniques have been used to compare the organization of mitochondrial DNA (mtDNA) from normal (N) and Texas male sterile (T) cytoplasms of maize. Bam H1 restriction fragments of normal mtDNA were cloned and used in molecular hybridizations against Southern blots of Bam H1 digested N and T mtDNA. Fifteen of the 35 fragments were conserved in both N and T as indicated by hybridization to comigrating bands in their restriction patterns. Only three fragments produced autoradiographs whose differences could reasonably be attributed to single changes in the cleavage site of the enzyme while approximately half (17/35) of the clones resulted in more complicated differences between N and T. The autoradiographs produced by these 17 clones indicated multiple cleavage site changes and/or sequence rearrangements of the mtDNA. Patterns of six of these 17 clones indicated partial duplication of the sequence and two showed variation in the intensity of hybridization between N and T, which may be related to the molecular heterogeneity phenomenon found in maize mitochondrial genomes. The large proportion of changes observed between N and T mtDNA indicates that rearrangements may have played an important role in the evolution of the maize mitochondrial genome.