bluuebunny/crossref_metadata_2025 huggingface dataset:
A biochemical analysis of cartilage proteoglycan in the avian mutant micromelia‐abbott
Authors: Quintner Mitchell I. , Goetinck Paul F.
Published: May 2005

Embryos 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

Mutations 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

In 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

The 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

Only 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

The 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

Experimental 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

The 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

The 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

The 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

We 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

Recombinant 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.
Induction of the shift in melanin synthesis in lethal yellow (Ay/a) mice in vitro
Authors: Tamate Hidetoshi B. , Takeuchi Takuji
Published: May 2005

Alleles at the agouti locus determines the type of pigment produced in hair‐bulb melanocytes. In order to analyze the mechanism of agouti gene function, an attempt was made to induce the shift in melanin synthesis in vitro. Skin explants from newborn yellow mice with genotype Ay/a were cultured with the method using membrane‐filter and roller tube. Production of black pigment in the hair bulbs was observed when the explants were cultured in the presence of α‐melanocyte stimulating hormone (α‐MSH). Electron‐microscopic observation indicates that the induced black pigments are eumelanin that is normally found in hair‐bulb melanocytes of genotypically black mice. The eumelanin synthesis was also induced by cAMP, DbcAMP, or theophylline. This α‐MSH‐induced eumelanin synthesis was suppressed by actinomycin D or cycloheximide, suggesting that the α‐MSH‐induced eumelanogenesis requires de novo transcription and/or translation.
Triploidy permits survival of an inviable amphibian hybrid
Authors: Elinson Richard P. , Briedis Andris
Published: May 2005

Hybrids between species frequently arrest early in development. In the frog hybrid Rana catesbeiana female × Rana clamitans male, the embryo shows a characteristic development to an exogastrula which dies. This hybrid can be rescued by pressure suppression of the second polar body, which results in the addition of another haploid set of R catesbeiana chromosomes to the embryo. The triploid hybrid expresses genes from both species and can develop normally through metamorphosis. The results show that an R catesbeiana egg containing a full haploid set of R clamitans chromosomes is capable of development and that the usual developmental arrest caused by the R clamitans genome responds to chromosomal dosage.
Intracellular cAMP in Dictyostelium discoideum: Characterization of an aggregation‐deficient mutant with elevated cAMP pools
Authors: Chan Fred K. , Coukell M. Barrie
Published: May 2005

Forty aggregation‐deficient mutants of Dictyostelium discoideum were screened for changes in intracellular cAMP during the first 10 hr of starvation. The pools in 39 of the mutants remained low and relatively static during this period. However, amoebae of one mutant, strain HC151, exhibited significantly elevated levels of intracellular cAMP during vegetative growth and for several hours after starvation. A more detailed analysis of this mutant indicated that the elevated cAMP pools in these cells are a consequence of the premature appearance and partial activation of an adenylate cyclase. The mutation(s) altering adenylate cyclase regulation in this strain appears to map in linkage group IV. Complementation tests between strain HC151 and another mutant, HH201, which has recently been shown to produce an adenylate cyclase activity precociously [1], indicated that the mutations affecting adenylate cyclase activity in these strains map at different loci. Although both of these mutations behave recessively in heterozygous diploids with respect to gross development, an examination of early cAMP metabolism and terminal spore differentiation in these diploids suggest that these mutations are at least partially expressed during some stage(s) of the developmental cycle.
Unlinked structural genes for the developmentally regulated isozymes of sn‐glycerol‐3‐phosphate dehydrogenase in mice
Authors: Kozak Leslie P. , Burkart Donna L. , Hjorth J. Peter
Published: May 2005

Genetic variants that affect the heat stability and ionic charge of the adult isozyme of glycerol‐3‐phosphate dehydrogenase (EC 1.1.1.8) map to a gene, Gdc‐1, located on chromosome 15. A second isozyme of glycerol‐3‐phosphate dehydrogenase, structurally homologous to the product of the Gdc‐1 locus and expressed predominantly in undifferentiated tissues, has previously been identified. We have now discovered an electrophoretic variant of this embryonic isozyme. This expression is determined by a codominant allele of the gene, Gdc‐2, that maps to the distal end of chromosome 9 as inferred from the observed gene order Mpi‐1–d‐Mod‐1–Gdc‐2.
Expression of genetically distinct superoxide dismutases in the maize seedling during development
Authors: Baum James A. , Scandalios John G.
Published: May 2005

Immunoassays for the cytosolic and mitochondrial superoxide dismutases (SOD) of maize were developed and used to study the expression of these proteins in the maize seedling. The genetically distinct proteins, SOD‐3 and SOD‐4, are preferentially expressed in the scutellum, comprising approximately 1% of the total water‐soluble protein of that tissue. SOD‐2, SOD‐3, and SOD‐4 are synthesized in the scutellum during early sporophytic development, probably on cytosolic ribosomes. Two‐dimensional gel electrophoresis of crude scutellar extracts indicates that significant changes occur in the protein composition of the maize scutellum following seed imbibition. Using the immunoassays, a maize line exhibiting a significant reduction in cyanide‐sensitive SOD protein was identified.
Developmental abnormalities in Drosophila induced by heat shock
Authors: Mitchell Herschel K. , Petersen Nancy S.
Published: May 2005

We have for some years been making use of phenocopies in Drosophila, as induced by heat shock, as tools for studies of the molecular events in morphogenesis [18, 21, 22]. In this paper, we have brought together some accumulated information on the conditions for phenocopy production, on a temporal sequence of sensitivity to induction, and on the nature of many of the morphogenetic abnormalities that can be induced. In general, the induction of phenocopies by heat shock requires conditions drastic enough to turn off transcriptional activities but not extreme enough to prevent recovery. This situation is most easily achieved in pupal stages where heat resistance is high, but even in this range, resistance varies with the stage of development.

The phenocopies described resemble, for the most part, mutants that affect structures derived from epithelial differentiation or muscle development.
Polygenic analysis of pattern formation in Drosophila: Specification of campaniform sensilla positions on the wing
Authors: Thompson James N. , Hellack Jenna J. , Kennedy John S.
Published: May 2005

This study was designed to measure the degree of correlation between vein formation and the specification of campaniform sensillae positions in the wing of Drosophila melanogaster. The campaniform sensillae are sensory organs placed at various locations on the wing. Those on the third longitudinal vein (L3) were the focus of this analysis. The system of polygenic modifiers of vein length is comparatively simple, as shown in whole chromosome assays of selected lines. This variability provides a sensitive method of altering vein‐forming ability and of assessing correlated changes in other parts of the vein pattern. In selection lines of veinlet, sensillae were displaced toward the base of the wing as vein length decreased by distal loss of vein material. Changes in the amount of vein were, however, not directly proportional to changes in sensillae positions. The more distal sensillae were shifted the largest amount. In the mutant tilt, in which reduced L3 vein‐forming competence results in subterminal gaps, distal campaniform sensillae were almost completely eliminated. The remaining sensillae were shifted toward the base of the wing where vein formation is normal. The placement of sensillae therefore appears to be sensitive to the same underlying determinants involved in vein‐forming competence.
Neural development in an imaginal disc mutant of Drosophila melanogaster
Authors: White Kalpana
Published: May 2005

The neural phenotype of an imaginal disc degenerate mutant l(1)d deg‐3 was studied in histological sections. The mutant larvae showed severe abnormalities in the imaginal neural development. Gynandromorphs, which are composed of genetically mutant and nonmutant cells, were generated and analyzed as late larvae. The results of mosaic analysis were consistent with l(1)d deg‐3 gene acting autonomously in the imaginal disc and imaginal neural cells. The optic lobe development patterns observed in the larval mosaics provided evidence for an eye disc‐optic lobe interaction during the late third instar larval stage.
Partial deficiencies in the myelin proteins of developing mice heterozygous for the shiverer mutation
Authors: Cammer Wendy
Published: May 2005

The central nervous system of the shiverer mouse is known to be severely deficient in myelin. Animals heterozygous for this autosomal‐recessive mutation were crossed, and the myelin proteins were examined in the brains and spinal cords of shiverers and unaffected littermates among the offspring. In the brains and spinal cords of nine of the 14 unaffected littermates examined, the quantities of the myelin basic and proteolipid proteins were lower than normal. Furthermore, in the brains of heterozygotes 33 to ∼ 150 days old, the myelin basic and proteolipid proteins were reduced in amount, compared to wild‐type controls; the myelin basic protein was also present in subnormal amounts in the spinal cords from heterozygous animals at the ages of 17 to 150 days. More severe reductions in the quantities of the myelin proteins were observed in central nervous system tissue from homozygous shiverer mice, and the quantity of the myelin proteolipid protein in the central nervous system of the shiverer mouse, expressed as a ratio to the control value at each age, underwent a developmental decline. In heterozygotes, as well as shiverers, the peripheral nerves were also deficient in the P1 and Pr proteins, which are the same as the basic proteins in rodent central nervous system myelin. The findings regarding heterozygotes suggest that the defective primary gene product in the shiverer mouse could be the myelin basic protein itself or a protein required for a rate‐limiting step in the processing of the myelin basic protein.
The late‐replicating X chromosome in digynous mouse triploid embryos
Authors: Endo Sumiyo , Takagi Nobuo , Sasaki Motomichi
Published: May 2005

Using BrdU‐labeling and acridine orange staining, the behavior of X‐chromosome replication was studied in 28 XXX and 19 XXY digynous mouse triploids. In some of these the paternal and maternal X chromosome could by cytologically distinguished. Such embryos were obtained by mating chromosomally normal females with males carrying Cattanach's X chromosome which contains an autosomal insertion that substantially increases the length of this chromosome. In the XXX triploids there were two distinct cell lines, one with two late‐replicating X chromosomes, and the other with only one late‐replicating X. The XXY triploids were also composed of two cell populations, one with a single late‐replicating X and the other with no late replicating X chromosome. Assuming that the late‐replicating X is genetically inactive, in both XXX and XXY triploids, cells from the embryonic region tended to have only one active X chromosome, whereas those from the extra‐embryonic membranes tended to have two active X chromosomes. The single active X chromosome was either paternal or maternal in origin, but two active X chromosomes were overwhelmingly maternal in origin, suggesting paternal X‐inactivation in extra‐embryonic tissues.
Mutant alleles that are altered in quantitative, organ‐specific behavior
Authors: Freeling Michael , Cheng David S.‐K. , Alleman Mary
Published: May 2005

Three new mutant alleles of maize alcohol dehydrogenase‐1 (Adh 1) were recovered following allyl alcohol selection of pollen. Each is altered in quantitative, organ‐specific, regulatory properties. All mutant sites act in cis to the structural gene component. One mutant arose spontaneously, one followed indirectly from irradiation with high Z accelerated particles, and one was induced by an autonomous mutator system. Each mutant is assessed in three organs by utilizing ADH allozyme ratios that were quantified at the level of ADH enzyme activity and either [3H]‐Leu incorporation into newly synthesized ADH 1 subunits or direct protein determinations. One mutation simultaneously raises Adh 1 expression in one organ and lowers it in another, another affects expression in one organ only, and another is extremely underexpressed in all organs but is unstable. This unstable allele has generated derivative mutant alleles that have less or zero ADH expression. We do not yet know whether or not coding sequences are involved in these mutants. We conclude that information for organ specificity and quantitative behavior resides near or within Adh 1 coding sequences.
Murine adult hematopoietic cells produce adult erythrocytes in fetal recipients
Authors: Blanchet Jean Paul , Fleischman Roger A. , Mintz Beatrice
Published: May 2005

Bone marrow cells from normal adult mice were introduced by microinjection via the placenta into W/Wv genetically anemic fetuses of 11 days' gestation. After birth, erythrocytes were fractionated by fluorescence‐activated cell sorting on the basis of antibody binding to a fetal‐specific antigen (Ft). Lysates of Ft‐positive, i.e., fetal, erythrocytes did not detectably contain hemoglobin of the donor type, as judged from electrophoresis of strain‐specific hemoglobin variants. Thus, adult hematopoietic bone marrow cells did not resume fetal differentiation despite their post‐transplant maturation in a fetal environment.
Temporal control of urate oxidase activity during development of the third‐instar larva of Drosophila: The role of 20‐hydroxyecdysone
Authors: Kral Leos G. , Johnson Daniel H. , Wing Mark , Friedman Thomas B.
Published: May 2005

The tissue‐specific enzyme urate oxidase is confined exclusively to the Malpighian tubules of Drosophila melanogaster and expressed only in the third‐instar larva and the adult. Shortly before pupariation urate oxidase activity declines precipitously and is not detectable 24 hours later. That 20‐hydroxyecdysone is the factor that triggers the disappearance of urate oxidase activity in late third‐instar larvae is demonstrated using the temperature sensitive mutant ecd1 which at the nonpermissive temperature of 29°C fails to accumulate a sufficient concentration of 20‐hydroxyecdysone necessary for puparium formation and thus remains a third‐instar larva for 1 to 2 weeks before death. Both the life cycle and the temporal profile of urate oxidase activity in ecd1 larvae at 19°C is identical to that of the wild type. However, at 29°C ecd1 third‐instar larvae retain high urate oxidase activity. A precipitous decline in urate oxidase activity is observed when ecd1 larvae at 29°C are fed 20‐hydroxyecdysone. These data implicate 20‐hydroxyecdysone in the process that controls the rapid decline of urate oxidase activity at the time of puparium formation. In whole homogenates of Malpighian tubules, the urate oxidase polypeptide was identified in SDS‐polyacrylamide gels by its Rf with respect to homogeneously pure Drosophila urate oxidase and also by immunoprecipitation with rabbit anti‐Drosophila urate oxidase IgG. Throughout development the amount of the urate oxidase polypeptide is correlated with the magnitude of urate oxidase activity.
XY female mice express H‐Y antigen
Authors: Johnson Lawrence L. , Sargent Evelyn L. , Washburn Linda L. , Eicher Eva M.
Published: May 2005

Karyotypically XY individuals of the C57BL/6J‐YPOS mouse stock develop as females or hermaphrodites, but never as normal males. The aberrant sexual development results from the interaction of the C57BL/6J genetic background with the M. poschiavinus‐derived Y chromosome. XY females from this stock were assayed for H‐Y antigen. By the criteria of skin‐grafting, the cell‐mediated lympholysis test, and the popliteal lymph node assay, these XY females are antigenically indistinguishable from normal C57BL/6 males. Implications for the hypothesis that H‐Y antigen induces formation of the mammalian testis are discussed.
Drosophila salivary gland proteins and pupation
Authors: Sarmiento Loveriza A. , Mitchell Herschel K.
Published: May 2005

Pulse‐labeling experiments of salivary glands from the prepupal stages of development showed selectively high rates of synthesis of a set of low molecular weight proteins (6K–12K). These proteins are stably maintained in the salivary glands during prepupal development and are subsequently transported to the pupation fluid (found between the pupal case and the prepupal cuticle) when pupation occurs. These small polypeptides are very basic with the major components having isoelectric points of 8.6–8.7 and the minor components having isoelectric points of 9.1–9.5. This study shows the continuing function of the salivary glands—specifically, the synthesis and secretion of a set of proteins with a putative role in pupation.
The relationship between gene dosage, gene expression, and sex in Drosophila
Authors: Lucchesi John C.
Published: May 2005

In Drosophila, the ratio of the number of X chromosomes to sets of other chromosomes initiates a series of events which result in sexual differentiation. In addition, this ratio establishes dosage compensation, a mechanism which equalizes the products of X‐linked genes in males and females. The present review discusses possible genetic entities responsible for the interpretation of chromosomal sex and subsequent sex‐mediated regulation during development.
Adaptation of Drosophila to temperature: Heat‐shock proteins and survival in Drosophila melanogaster
Authors: Stephanou G. , Alahiotis S. N. , Christodoulou C. , Marmaras V. J.
Published: May 2005

Two stocks of Drosophila melanogaster, one sensitive (6.5% survival) and one resistant (76.24%) to heat shock (40°C/25 min) were derived through indirect selection [1]. Genetic analysis of heat‐sensitive and heat‐resistant lines we had selected revealed that the survival rate is chiefly determined by cytoplasmic inheritance but also depends to some extent on the nucleus [1]. The ability of the fly to survive thermal stress was found to have an excellent correlation with the kinetics of protein synthesis in ovaries or glands subjected to heat treatment. The incorporation rate of 35S‐methionine into proteins was found to be higher for strains exhibiting higher survival (R1, R1S1) than for strains with a lesser ability (S1, S1 R1) to survive heat shock. Moreover, the intensity of labeling of the proteins synthesized and especially of the hsps (heat‐shock proteins) after the heat shock is higher in the R1 and R1S1 stocks than in the S1 and S1R1 stocks. This convergence between survival and the cellular level of hsps (both manipulated by selection) bears on the physiological significance of these proteins which seems to participate in the control of the survival as an additive component.
Developmental genetic analysis of lethal alleles at the ewg locus and their effects on muscle development in Drosophila melanogaster
Authors: Fleming Robert J. , Zusman Susan B. , White Kalpana
Published: May 2005

The recessive X‐linked mutation erect wing (ewg), in Drosophila melanogaster, was characterized as a flightless behavioral mutant which specifically lacked the dorsal longitudinal flight muscles [1]. This mutation was mapped distal to the X chromosomal locus yellow, and further to the cytological segment 1 A 1 to 1 B2‐3 [2]. Several lethal complementation groups have been mapped to this interval [3]. Our complementation tests show that ewg is allelic to one lethal complementation group in the region 1 A 1 to 1 B2‐3. A further analysis of ewg and several lethal alleles isolated at this locus was undertaken in the present investigation. Most of the lethal alleles at this locus lead to a late embryonic or early larval lethal phase, indicating that the ewg+ gene product is necessary for the development of more than just the dorsal longitudinal flight muscles. Intragenic complementation was observed for some of the ewg lethal alleles. Genetic mosaics with ewg lethal alleles showed that mutant cell clones in cuticular structures are viable. Mosaic analysis is consistent with a mesodermal defect associated with the locus.
Lethal nonagouti (ax): Description of a second embryonic lethal at the agouti locus
Authors: Papaioannou Virginia E. , Mardon Helen
Published: May 2005

The time and mode of action of the homozygous ax gene, lethal nonagouti, has been investigated on the inbred AX/Pa background. Heterozygotes were mated inter se to produce 25% homozygous embryos and heterozygotes were mated with homozygous, nonagouti mice to provide control litters. Comparisons of the frequency of mating success, the ratio of implantation sites to ovarian ovulation sites, and the average litter sizes between experimental and control matings all indicated that ax/ax embryos are not lost prior to implantation. Histological examination of pregnant uteri indicated that ax/ax embryos are first evident as abnormal blastocysts at 4.5 days post coitum (pc). These implant and develop to varying degrees, some differentiating trophoblast giant cells and a primitive endoderm layer. Growth is retarded and only small, disorganized clumps of tissue remain by 7.5 and 8.5 days pc. The time and mode of gene action of lethal nonagouti is thus different from its allele, lethal Yellow.
The control of IgM expression in a murine B cell lymphoma
Authors: Irick Holly A. , Sibley Carol H.
Published: May 2005

The regulation of IgM expression was studied in clones derived from a murine B lymphocyte cell line, WEHI279.1. During normal B cell development IgM heavy chain synthesis increases concomitantly with heightened IgM secretion and reduced cell‐surface IgM. However, in these subclones, the levels of membrane‐bound and secreted IgM were regulated independently of one another. The amount of IgM secreted by the cells was tightly coupled to the amount of heavy chain synthesis, suggesting that the major control of secretion is pretranslational. Surface IgM exhibited a more complex regulation, with both pre‐ and posttranslational components. Variation in the expression of both forms of IgM occurred at high frequency. Although IgM expression follows a unidirectional pathway in nontransformed cells, the variability in these tumor cells was reversible and cellautonomous. High levels of phenotypic variability may be important in the ability of transformed cells to escape the immune response.
Genetic analysis of cell adhesion
Authors: Loomis William F.
Published: May 2005

Cellular adhesion is what keeps cells together in multicellular organisms. Cells adhere to each other, to extracellular matrices, and to the substratum. Biochemical analyses of these processes have suggested some of the types of surface molecules which may be involved, but definitive evidence must rely on effective reconstruction of functional membranes or genetic alteration of the pertinent genes. Together these approaches may give us a better understanding of how cells sort out and form tissues during development.
Genetics of microcystless mutants of polysphondylium pallidum
Authors: Francis David , Rupar Mark
Published: May 2005

Mutants were selected that are incapable of differentiating microcysts, a resting stage formed in response to high osmotic conditions. In the selection procedure amebae that failed to encyst were removed by flotation in 46% Percoll. Genetic crosses among 15 mutant strains were made by means of the macrocyst sexual cycle. Eleven of the strains mapped to three loci. Mutations at two of these loci (cysA and cysB) produced no observable alteration in the aggregation‐fruiting pathway, although one set of strains altered at the cysA locus carried defects at a second unlinked site which blocked aggregation. The single strain that defined the third locus (cysC) is aggregateless. These results confirm the conclusion that there are several genes whose function is essential to microcyst development and is exclusive to this pathway. It remains uncertain whether there are other genes whose action is crucial to both encystment and to aggregation/fruiting.
Behavioral mutants of Drosophila melanogaster. IV. Analysis of developmentally temperature‐sensitive mutations affecting flight
Authors: Homyk Theodore , Grigliatti Thomas A.
Published: May 2005

Mutations in 13 genes with temperature‐sensitive (ts), flightless phenotypes have been examined. All hop and fly well when raised at the permissive temperature, but fly poorly, or not at all, when raised at the restrictive temperature. The mutations were divided into three groups on the basis of their temperature‐sensitive periods (TSPs) for flightlessness. The TSPs for mutations at five loci, fli‐C1, D1, E1, I1, and shak A1, in the first group are confined to 24 to 48 hr interval during early pupal development. Mutations in the second group, including eag101, fli B1, and futs1 have continuous TSPs 3 to 4 days in length, extending from late larval through the early pupal stages. The flight TSPs for mutations in the third class, including fli J1, fli K2, flrd H3, and flrd N1, are almost continuous, and span most of the larval and pupal periods. Many of the mutations have pleiotropic phenotypes, including semilethality and lethality, and wing posture and cuticle abnormalities, with discernible TSPs. One of the more intriguing pleiotropic phenotypes is the ts optomotor response exhibited by fli J2, the TSP for which extends from late larval through late pupal stages.
Gene expression during early kernel development in Zea mays
Authors: Chandlee Joel M. , Scandalios John G.
Published: May 2005

The timing of gene expression in the endosperm of developing F1 maize kernels was investigated. Zymogram analysis revealed the presence of maternally derived allelic gene products on all days investigated, but activity of paternally derived allelic gene products is not detectable until days 6–8 postpollination, depending on the particular cross used and the enzyme investigated. This pattern holds true for eight different isozymes of five different enzyme systems, including catalase, alcohol dehydrogenase, glutamate‐oxaloacetate transaminase, endopeptid́ase, and aminopeptidase. An increase in specific activity for catalase, alcohol dehydrogenase, and endopeptidase correlates precisely with the day of visualization of the paternally derived allelic gene product on the zymograms. Rocket immunoelectrophoresis confirms a dramatic increase in catalase and alcohol dehydrogenase protein levels on the day the paternally derived allelic gene product is first detected on zymograms. Appropriate crosses utilizing three different allelic variants revealed the presence of enzyme of maternal plant origin within the endosperm prior to day 6 postpollination.

Maize kernels were cultured in vitro on an agar‐based medium as early as 3 days postpollination. Using medium supplemented with actinomycin D or cycloheximide, it was possible to localize the critical time periods for transcription and translation of the paternally derived allele in the F1 hybrids. For aminopeptidase (AMP‐1, AMP‐3) and endopeptidase (ENP‐1), transcription occurs as early as 3–4 days postpollination, and translation of the transcripts starts at about 4–5 days postpollination. Although the evidence is indirect, it is likely that the maternally derived allele of the F1 kernels is activated (ie, begins transcribing) synchronously with the paternally derived allele during this early developmental time period.
Food deprivation is not a prerequisite for the amoebal to plasmodial transition in Physarum polycephalum
Authors: Pallotta Dominick , Blanchard Serge , Larue Hélène
Published: May 2005

The effect of food supply on the onset of asexual and sexual plasmodium formation in Physarum polycephalum was studied. Asexual differentiation occurs readily in amoebae carrying the matAh mating type allele. The density at which these amoebae begin to differentiate is influenced by the ind locus, which controls the production of a diffusible inducer. The alleles ind‐1 and ind‐2 are known. Strains carring the ind‐1 allele begin plasmodium formation at a low amoebal density (rapid differentiation), while strains carring the ind‐2 allele differentiate at a higher amoebal density (slow differentiation). The onset of differentiation is characteristic of the strain and did not change with a 20‐fold variation in the number of food bacteria available. Sexual differentiation occurs between compatible amoebal strains. For a given pair of amoebal strains the onset of plasmodium formation occurs at a characteristic cell density that is determined by the genetic backgrounds of the strains. The ind locus is one of the genes that influences this cell density. Plasmodia are formed at a lower cell density in crosses involving compatible amoebae carrying the ind‐1 allele than they are in crosses with strains carrying the ind‐2 allele. As was found for asexual differentiation, an approximate 20‐fold variation in the food supply did not affect the initiation of sexual plasmodium formation. These results suggest that in most cases starvation does not trigger the differentiation of amoebae into plasmodia. The time of onset of plasmodium formation is determined largely by genetic factors.
Evidence for a Mendelian factor controlling the cytokinin requirement of cultured tobacco cells
Authors: Meins Frederick , Foster Rachel , Lutz Joseph D.
Published: May 2005

Cultured leaf tissues of Nicotiana tabacum L. cv. “Havana 425” normally require an exogenous source of cytokinin for rapid growth; stem‐cortex tissues do not—ie, they exhibit the cytokinin‐habituated phenotype. We found that plants regenerated from cloned cortex and leaf tissues from one particular plant differed in leaf‐tissue phenotype: Leaf tissues derived from leaf cells exhibited the normal, nonhabituated phenotype, whereas leaf tissues derived from cortex cells were cytokinin‐habituated. This difference in leaf phenotype was not found using leaf and cortex cells from six other donor plants. The inheritance of the habituated leaf trait was studied in tissues from cortex‐derived plants and hybrids between these plants and normal plants. F1 hybrids were intermediate between the parental types in degree of habituation. No differences were found between reciprocal hybrids. These results suggest that the habituated leaf trait is an incompletely dominant, nuclear trait. Both parental and intermediate phenotypes were recovered in the F2 progeny. The frequency of habituated leaf progeny in the F2 and backcross populations provide evidence that the trait is regulated at a single genetic locus.
Production and properties of mouse trisomy 15 ⟷ diploid chimeras
Authors: Epstein Charles J. , Smith Sandra , Cox David R.
Published: May 2005

Mouse trisomy 15 ⟷ 2n aggregation chimeras have been produced and analyzed at 19 days of gestation. We have found that these chimeras are viable and in most instances normal in external appearance, unlike trisomy (Ts)‐15 embryos which are severely growthretarded and die midway through gestation. Trisomic cells were found in all tissues of fetal chimeras, with proportions not significantly different from those of the controls in kidney, heart, liver, and brain, but significantly reduced in thymus and spleen. Ts‐15 cells do not, therefore, exhibit a proliferative advantage during fetal development of tissues susceptible to Ts‐15‐related lymphoid malignancies. However, the presence of Ts‐15 cells in the placenta may be associated with placental overgrowth. One fetus containing a monosomy 3 cell population was also observed, the first term fetal chimera with monosomic cells that has been detected.