| distribution of split 5.8s ribosomal rna in diptera. | although the 5.8s ribosomal rna (rrna) of most eucaryotes consists of 155-170 nucleotides, in two dipterous species the 5.8s rrna consists of two pieces, 123 and 30 nucleotides in length. the distribution of split 5.8s rrna was studied in other diptera and the most closely related order siphonaptera to learn the origin of split 5.8s rrna. four species of mosquitoes, culex tritaeniorhynchus, culex pipiens molestus, aedes albopictus, anopheles sp. (culicidae) had a single 5.8s rrna consisting of a ... | 1992 | 1343775 |
| the promoter of dna puff gene ii/9-1 of sciara coprophila is inducible by ecdysone in late prepupal salivary glands of drosophila melanogaster. | dna puffs occur in sciarid salivary gland chromosomes; they are sites of dna amplification and intense transcription and they appear to encode secreted structural proteins needed for pupation. in this report we have used p-element transformation of drosophila to study regulation of a sciara dna puff gene. we found that a 718-bp promoter fragment of dna puff gene ii/9-1 from sciara coprophila directs expression of the bacterial reporter gene cat in late prepupal salivary glands of transgenic dros ... | 1991 | 1809395 |
| sequence relationship of retrotransposable elements r1 and r2 within and between divergent insect species. | r1 and r2 are retrotransposable elements that integrate at specific sites in the 28s ribosomal rna (rrna) genes of bombyx mori and drosophila melanogaster. we have previously shown that most insect species contain insertions in their 28s genes at the r1 and/or r2 site. we have sequenced the 3' half of r1 and r2 elements from three additional insect species: the fungus gnat, sciara coprophila (diptera); the japanese beetle, popillia japonica (colleoptera); and the parasitic wasp, nasonia vitripen ... | 1993 | 8383793 |
| origin recognition complex binding to a metazoan replication origin. | the initiation of dna replication in eukaryotic cells at the onset of s phase requires the origin recognition complex (orc) [1]. this six-subunit complex, first isolated in saccharomyces cerevisiae [2], is evolutionarily conserved [1]. orc participates in the formation of the prereplicative complex [3], which is necessary to establish replication competence. the orc-dna interaction is well established for autonomously replicating sequence (ars) elements in yeast in which the ars consensus sequen ... | 2001 | 11566101 |
| heterologous rrna gene expression: internal fragmentation of sciara coprophila 28s rrna within microinjected xenopus laevis oocytes. | species-specific pre-rrna processing variations may result in fragmented 18s, 5.8s and 28s rrnas. some insect 5.8s and 28s rrnas are further cleaved, creating within a 'hidden break' or 'gap'. we investigated the specificity of the processing mechanism by microinjecting sciara coprophila (fungus fly) rdna into xenopus laevis oocytes to examine insect rrna maturation within a cell where endogenous rrnas are not cleaved at homologous sites. results confirm insect rdna transcription and pre-28s rrn ... | 2005 | 16164608 |
| ribosomal dna of fly sciara coprophila has a very small and homogeneous repeat unit. | in this report we show by hybridization of restriction fragments and by miller spreads that the unit repeat of the fly sciara coprophila is only 8.4 kb which is the smallest known for a multicellular eukaryote. the 8.4 kb ecor1 fragment containing a complete unit of sciara rdna was cloned in pbr322, and mapped by the method of parker (1977) and also by double digestions. the coding regions for 28s, 18s, and 5.8s rna were localized by the method of berk and sharp (1977). from these data we conclu ... | 1986 | 288964 |
| further studies of the nucleolar material in salivary gland nuclei of sciara coprophila. | | 2014 | 4116206 |
| isolation and characterization of the ecdysone receptor and its heterodimeric partner ultraspiracle through development in sciara coprophila. | regulation of dna replication is critical, and loss of control can lead to dna amplification. naturally occurring, developmentally regulated dna amplification occurs in the dna puffs of the late larval salivary gland giant polytene chromosomes in the fungus fly, sciara coprophila. the steroid hormone ecdysone induces dna amplification in sciara, and the amplification origin of dna puff ii/9a contains a putative binding site for the ecdysone receptor (ecr). we report here the isolation, cloning, ... | 2013 | 23321980 |
| rrna processing: removal of only nineteen bases at the gap between 28s alpha and 28s beta rrnas in sciara coprophila. | we have determined the sequence of the rdna region between the 28s alpha and 28s beta rrna coding segments (termed a "gap") in the insect sciara coprophila, and have used s1 nuclease mapping and cdna primer extension to define the 5' and 3' boundaries of the gap. only 19 bases found in rdna at the gap region are absent from mature 28s rrna. eukaryotic rrnas contain stretches of nucleotides ("expansion segments") which are absent in e. coli rrna. the gap region in sciara is located within expansi ... | 1985 | 2989775 |
| the potential for using entomopathogenic nematodes to control darkwinged fungus gnats bradysia coprophila (lintner) on succulents in glass houses. | darkwinged fungus gnat bradysia coprophila lintner (diptera: sciaridae) is known as a pest of ornamental plants in commercial green and glass houses in nurseries worldwide. there have been reports about significant bradysia coprophila damage of succulent plants in five botanical gardens in ukraine, including academician fomin's botanical garden (kiev) for the last three years. in pot experiments the commercial strain of s.feltiae to control b. coprophila was tested on mammilaria, opuntia, echino ... | 2015 | 27145569 |
| the gene transformer-2 of sciara (diptera, nematocera) and its effect on drosophila sexual development. | the gene transformer-2, which is involved in sex determination, has been studied in drosophila, musca, ceratitis, anastrepha and lucilia. all these members of diptera belong to the suborder brachycera. in this work, it is reported the isolation and characterisation of genes transformer-2 of the dipterans sciara ocellaris and bradysia coprophila (formerly sciara coprophila), which belong to the much less extensively analysed sciaridae family of the suborder nematocera, which is paraphyletic with ... | 2011 | 21406087 |
| evaluation of medium treatments for management of frankliniella occidentalis (thripidae: thysanoptera) and bradysia coprophila (diptera: sciaridae). | two greenhouse experiments, each comprising two trials, were conducted to evaluate medium drenches of insect growth regulators and conventional insecticides to reduce emergence of adult western flower thrips, frankliniella occidentalis (pergande), and fungus gnats, bradysia coprophila (lintner) from the medium. in the insect growth regulator trials, diflubenzuron and pyriproxyfen provided the greatest reduction in thrips emergence, and fenoxycarb, pyriproxyfen and azadirachtin resulted in the mo ... | 2001 | 11802598 |
| developmental gene amplification: insights into dna replication and gene expression. | in the formation of a complex organism and the differentiation of specific cell types, there are often demands for high levels of particular gene products. these demands can be met by increasing transcription or translation, or by decreasing the rate of mrna or protein turnover. although these are the most common means to increase expression levels, there is another mechanism: gene amplification. developmental gene amplification is a dna replication-based process whereby specific genes are repli ... | 2005 | 15734574 |
| the gene sex-lethal of the sciaridae family (order diptera, suborder nematocera) and its phylogeny in dipteran insects. | this article reports the cloning and characterization of the gene homologous to sex-lethal (sxl) of drosophila melanogaster from sciara coprophila, rhynchosciara americana, and trichosia pubescens. this gene plays the key role in controlling sex determination and dosage compensation in d. melanogaster. the sxl gene of the three species studied produces a single transcript encoding a single protein in both males and females. comparison of the sxl proteins of these nematocera insects with those of ... | 2004 | 15514063 |
| molecular characterization of dna puff ii/9a genes in sciara coprophila. | a cdna clone, psdii/9, that hybridizes in situ to ecdysone-regulated dna puff ii/9a in sciara coprophila was used as a probe to isolate a sciara genomic clone. lambda psdii/9, which contains a 14.7 x 10(3) base-pair dna insert. the full-length cdna insert was sequenced and mapped to gene ii/9-1 on the genomic clone. a second gene (ii/9-2), transcribed in the same direction as ii/9-1, was also mapped to lambda psdii/9, and its nucleic acid sequence was found to be 85% similar to that of gene ii/9 ... | 1989 | 2614832 |
| 5-methylcytosine in the dna of the polytene chromosomes of the diptera sciara coprophila, drosophila melanogaster and d. persimilis. | 5-methylcytosine has been detected in the dna of the polytene chromosomes of sciara coprophila, drosophila melanogaster and d. persimilis, using specifically purified antibodies to 5-methylcytidine. the 5-methylcytosine is present in gc-rich sequences in the bands. virtually no 5-methylcytosine is detectable in mitotic metaphase chromosomes of s. coprophila. thus, methylation is associated with polytenization in these diptera. restriction enzyme studies using hpaii, mspi, hhai and alui indicate ... | 1980 | 6772415 |
| treasure your exceptions: an interview with 2017 george beadle award recipient susan a. gerbi. | the genetics society of america's (gsa) george w. beadle award honors individuals who have made outstanding contributions to the community of genetics researchers and who exemplify the qualities of its namesake. the 2017 recipient is susan a. gerbi, who has been a prominent leader and advocate for the scientific community. in the course of her research on dna replication, gerbi helped develop the method of replication initiation point (rip) mapping to map replication origins at the nucleotide le ... | 2017 | 29203696 |
| whole organism genome editing: targeted large dna insertion via obligare nonhomologous end-joining in vivo capture. | targeted gene insertion is a goal of genome editing and has been performed in cultured cells but only in a handful of whole organisms. the existing method to integrate foreign dna using the homologous recombination pathway is inherently low efficiency, and many systems are refractory to this method. several additional manipulations have been developed to gain greater efficiency by suppressing the competing dominant repair pathway of nonhomologous end-joining. however, this can be laborious and i ... | 2015 | 26139843 |
| the ecdysone receptor (scecr-a) binds dna puffs at the start of dna amplification in sciara coprophila. | the steroid hormone ecdysone induces dna amplification and subsequent dna puff formation in late fourth larval instar salivary gland polytene chromosomes of the fungus fly, sciara coprophila. previous in vitro studies on dna puff ii/9a in sciara demonstrated that the ecdysone receptor (scecr-a) efficiently binds an ecdysone response element adjacent to the origin recognition complex binding site within the ii/9a amplification origin, implying a role for scecr-a in amplification. here, we extrapo ... | 2013 | 23737076 |
| histone h3 phosphorylation and elimination of paternal x chromosomes at early cleavages in sciarid flies. | in sciarid flies (diptera, sciaridae), one or two paternally derived x chromosomes are discarded from the soma at early cleavages to determine the sex of the embryo (xx, females; x0, males). x chromosome(s) elimination is achieved by an abnormal anaphase segregation so that x sister chromatids do not reach the poles and are not included in the daughter nuclei. a cis-acting locus (ce) within the heterochromatin proximal to the centromere is known to regulate x chromosome elimination. by immunoflu ... | 2013 | 23660000 |
| molecular and cytological characterization of repetitive dna sequences from the centromeric heterochromatin of sciara coprophila. | sciara coprophila (diptera, nematocera) constitutes a classic model to analyze unusual chromosome behavior such as the somatic elimination of paternal x chromosomes, the elimination of the whole paternal, plus non-disjunction of the maternal x chromosome at male meiosis. the molecular organization of the heterochromatin in s. coprophila is mostly unknown except for the ribosomal dna located in the x chromosome pericentromeric heterochromatin. the characterization of the centromeric regions, thus ... | 2011 | 21533987 |
| histone h3 phosphorylation and non-disjunction of the maternal x chromosome during male meiosis in sciarid flies. | an extremely unorthodox method of chromosome segregation is found in sciarid flies (diptera, sciaridae), where at male meiosis, the whole paternal complement is eliminated and the maternal x chromosome undergoes non-disjunction. at meiosis i, a monopolar spindle directs the segregation of maternal chromosomes to the single pole, whereas paternal chromosomes are discarded. at meiosis ii, although maternal autosomes segregate normally, the x chromosome remains undivided. a cis-acting locus within ... | 2011 | 21511731 |
| two new chromodomain-containing proteins that associate with heterochromatin in sciara coprophila chromosomes. | we report here the molecular and cytological characterization of two proteins, scohet1 and scohet2 (for sciara coprophila heterochromatin), which associate to constitutive heterochromatin in the dipteran s. coprophila. both proteins, scohet1 of 37 kda and scohet2 of 44 kda, display two chromodomain motifs that contain the conserved residues essential for the recognition of methylated histone h3 at lysine 9. we raised antibodies to analyze the chromosomal location of scohet1 and scohet2 in somati ... | 2009 | 19205716 |
| genome size and determination of dna content of the x chromosomes, autosomes, and germ line-limited chromosomes of sciara coprophila. | the unique chromosome biology of the fungus fly sciara coprophila has fascinated investigators for over 80 years. male meiosis exhibits a monopolar spindle, nonrandom segregation of imprinted chromosomes and nondisjunction of the x chromosome. the unusual mechanism of sex determination requires selective elimination of x chromosomes in embryogenesis. supernumerary (l) chromosomes are also eliminated from the soma during early cleavage divisions. distinctive dna puffs on the larval salivary gland ... | 2006 | 17051543 |
| ecdysone induces transcription and amplification in sciara coprophila dna puff ii/9a. | dna replication is normally tightly regulated to ensure the production of only one copy of the genome per cell cycle. however, dna puffs of the salivary gland giant polytene chromosomes of sciara coprophila undergo dna amplification during the normal course of development, overriding this control. this developmental strategy provides more template for the production of large amounts of protein needed for pupation. we have focused on dna puff ii/9a, which amplifies approximately 17-fold over the ... | 2006 | 16938289 |
| [use of the modified method of chromatin immunoprecipitation for the isolation of actively transcribed loci]. | a modified version of the chromosomal immunoprecipitation (chip) assay was implemented for discrete isolation and characterization of actively transcribed genes. specifically, it was demonstrated with the gene ii/9-1 of sciara coprophila as a model locus that significant enhancement in the isolation of actively transcribed versus repressed and inactive genes can be achieved through the chip methodology. a combination of solid-phase magnetic bead technology with chromosomal immunoprecipitation us ... | 2013 | 12624958 |
| a dnase i hypersensitive site flanks an origin of dna replication and amplification in sciara. | in chromosomes of metazoa, the assembly of the genome into chromatin makes an important but poorly understood contribution to determining where dna replication will initiate. we addressed this issue by studying the developmental progression of the location of the dna replication origin (ori) and alterations in chromatin structure in one of the best-mapped oris in metazoa, that found in dna puff ii/9a of the fly sciara coprophila. we found that dna synthesis for both normal chromosomal endoduplic ... | 2002 | 12474058 |
| maintenance of the dna puff expanded state is independent of active replication and transcription. | the maintenance of the expanded state of dna puffs ii/2b and ii/9a in polytene chromosomes from stage 14 x 7 sciara coprophila salivary glands was assayed after inhibition of rna synthesis, dna synthesis, or both processes together. heat shock conditions were established in order to inhibit transcription. polypeptides of mr 72,000 and 36,000 were produced in sciara after heat shock. the gene encoding the mr 72,000 polypeptide, the homolog of drosophila hsp70, was cloned. in situ hybridization de ... | 2001 | 11513293 |
| incomplete sister chromatid separation is the mechanism of programmed chromosome elimination during early sciara coprophila embryogenesis. | sex in sciara coprophila is determined by maternally supplied factors that control the number of paternal x chromosomes eliminated during the syncytial embryonic divisions. confocal microscopy and fish demonstrate that the centromeres of the x chromosomes separate at anaphase and remain functional during the cycle in which the x chromosomes are eliminated. however, a region of the sister chromatids fails to separate and the x chromosomes remain at the metaphase plate. this indicates that failure ... | 1996 | 9012499 |
| analysis of an origin of dna amplification in sciara coprophila by a novel three-dimensional gel method. | the replication origin region for dna amplification in sciara coprophila dna puff ii/9a was analyzed with a novel three-dimensional (3d) gel method. our 3d gel method involves running a neutral/neutral 2d gel and then cutting out vertical gel slices from the area containing replication intermediates, rotating these slices 90 degrees to form the third dimension, and running an alkaline gel for each of the slices. therefore, replication intermediates are separated into forks and bubbles and then a ... | 1994 | 8289825 |
| unorthodox male meiosis in trichosia pubescens (sciaridae). chromosome elimination involves polar organelle degeneration and monocentric spindles in first and second division. | male meiosis in trichosia pubescens (sciaridae) was investigated by means of serial section electron microscopy and immunofluorescence light microscopy. from earlier studies of another sciarid fly, sciara coprophila (phillips (1967) j. cell. biol. 33, 73-92), it is known that the spindle poles in sciarid spermatogonia are characterized by pairs of 'giant centrioles', ring-shaped organelles composed of large numbers of singlet microtubules. in the present study spermatocytes in early prophase of ... | 1994 | 8175917 |
| developmental progression of dna puffs in sciara coprophila: amplification and transcription. | dna amplification for two major dna puffs (ii/2b and ii/9a) of the fungus fly sciara coprophila increases steeply from 17 to 19 days after hatching (18 degrees c), resulting in almost 20-fold more dna at these loci in mature larval salivary glands than in adult tissues. at 19 days after hatching when gene amplification reaches a plateau, there is a burst in the amount of mrna encoded by these two dna puffs. expansion of the two puffs coincides with the increase in transcription rather than reini ... | 1993 | 8224550 |
| replication initiates at a confined region during dna amplification in sciara dna puff ii/9a. | two independent two-dimensional (2d) gel methods were used to map an origin of replication that is developmentally regulated by the steroid hormone ecdysone, namely an origin for dna puff amplification in the fungus fly sciara coprophila. initiation of replication was found to occur within a small region of no larger than 6 kb by use of the neutral/neutral 2d gel method. neutral/alkaline 2d gel analyses support the results of the neutral/neutral 2d gels and further define within the origin regio ... | 1993 | 8504930 |
| dna amplification in dna puff ii/9a of sciara coprophila. | | 1993 | 7956063 |
| a sequence-specific protease cleaves a maternal, cortical protein during early embryogenesis in sciara coprophila (diptera). | one of the first events of egg activation in sciara coprophila (diptera) is the disappearance of an abundant maternal 38-kda protein (p38) and the simultaneous emergence of an abundant 35-kda protein (p35). western blotting experiments using monoclonal antibodies directed against p38 reveal that p38 and p35 are serologically related and indicate that maternal p38 is transformed into p35 during early development. this transition is possibly accompanied by a conformational change in the part of th ... | 1990 | 2197136 |
| isolation and characterization of ribosomal dna variants from sciara coprophila. | the ribosomal rna multigene family in the fungus fly sciara coprophila contains a total of only 65 to 70 repeat units. we explored the types and frequencies of variant repeats in this small multigene family by characterizing different cloned rdna variants from sciara. although we did not observe any intergenic spacer length variants in sciara, we found a variant due to the insertion of a putative mobile element (lambda bc11), and variants containing ribosomal insertion elements. by dna sequence ... | 1989 | 2555520 |
| exposure of salivary gland cells to low-frequency electromagnetic fields alters polypeptide synthesis. | this study demonstrates that exposure of cells to extremely low-frequency electromagnetic fields can cause measurable changes in protein synthesis. sciara coprophila salivary gland cells were exposed to five low-frequency (1.5-72 hz) electromagnetic signals: three signals (1.5, 15, and 72 hz) produced pulsed asymmetric electromagnetic fields and two signals (60 and 72 hz) were sinusoidal. subsequent analyses of two-dimensional gels showed that cell exposure to either type of low-frequency electr ... | 1988 | 3375247 |
| nonrandom chromosome arrangements in germ line nuclei of sciara coprophila males: the basis for nonrandom chromosome segregation on the meiosis i spindle. | meiosis i in males of the dipteran sciara coprophila results in the nonrandom distribution of maternally and paternally derived chromosome sets to the two division products. based on an earlier study (kubai, d.f. 1982. j. cell biol. 93:655-669), i suggested that the meiosis i spindle does not play a direct role in the nonrandom sorting of chromosomes but that, instead, haploid sets are already separated in prophase nuclei well before the onset of spindle formation. here i report more direct evid ... | 1987 | 3693389 |
| appearance of two maternally directed histone h2a variants precedes zygotic ubiquitination of h2a in early embryogenesis of sciara coprophila (diptera). | a monoclonal antibody raised against drosophila histone h2a.l (15 kda) recognizes two h2a isoforms, h2as (16kda) and h2af (15 kda), and a modified ubiquitinated form, uh2a (25 kda), in the fungus gnat sciara coprophila. both variants derive from different mrnas as shown by in vitro translation, immunoprecipitation, and fluorography. whereas h2af is present throughout embryogenesis, the sciara-specific variant h2as is preferentially expressed during cleavage. these developmental profiles reflect ... | 1987 | 22272423 |
| transcriptional patterns in the x chromosome of sciara coprophila following exposure to magnetic fields. | we previously demonstrated that exposure of salivary gland cells of the dipteran, sciara coprophila, to either asymmetrical or symmetrical changing magnetic fields results in an increase in the incorporation of radioactive uridine into rna. the present report is an analysis of the grain count distribution over the x chromosome of sciara in transcription autoradiograms following exposure of the salivary gland cells to two pulsed magnetic signals and a 72-hz sine wave signal. the results show augm ... | 1987 | 3579993 |
| meiosis in sciara coprophila: structure of the spindle and chromosome behavior during the first meiotic division. | light microscope descriptions of meiosis i in males of the fungus gnat sciara coprophila suggested the presence of a monopolar spindle in which maternal and limited chromosomes move poleward while paternal chromosomes "back away" from the pole. the ultrastructural analysis reported here, based upon serial sections of cells in different stages of meiosis i, shows that the spindle is indeed monopolar with a distinctive differentiation, the polar complex, at one pole. this complex is the focus of a ... | 1982 | 7118997 |
| inverse relationship between transcriptional activity and 5-methylcytosine content of dna in polytene chromosomes of sciara coprophila. | | 1981 | 6171439 |
| two distinct intervening sequences in different ribosomal dna repeat units of sciara coprophila. | we have prepared a partial gene library of sheared dna from the fungus fly, sciara coprophila, by da-t tailing and insertion into pbr322. two ribosomal dna clones which differ from the usual ribosomal dna organization in this organism were studied in detail. clone pbc 1l-1 has an intervening sequence of 1.4 kb, and clone pbc 6d-6 has an intervening sequence of 0.9 kb. these intervening sequences occur in about the same position in 28s rdna, but do not appear to share sequence homology with one a ... | 1981 | 7279671 |
| spermatogenesis in sciara coprophila. i. chromosome orientation on the monopolar spindle of meiosis i. | meiosis i of spermatogenesis in the fungus fly, sciara coprophila, has a monopolar spindle which collects the maternal and supernumerary l chromosome sets, while the paternal chromosomes migrate away from the single pole to be excluded in a bud. by inspection, the metacentric paternal chromosome iv moves with its centromere lagging rather than leading the direction of motion. therefore, we wondered if all paternal homologues move in such a reverse orientation. to determine the orientation of the ... | 1981 | 7261717 |
| spermatogenesis in sciara coprophila. ii. precocious chromosome orientation in meiosis ii. | in the second meiotic division of spermatogenesis in sciara coprophila the x dyad undergoes a directed nondisjunction appearing precociously at one pole. all other chromosomes behave in a normal fashion aligning on the metaphase plate and dividing. crouse has determined that this directed nondisjunction is governed by a region of the x centromere heterochromatin known to contain the rdna (crouse et al., 1977; crouse, 1979). in order to further characterize this system we have utilized dapi c-ban ... | 1981 | 7196316 |
| coding and spacer sequences in the 5.8s-2s region of sciara coprophila ribosomal dna. | the sequence of 436 nucleotides around the region coding for 5.8s rna in the sciara coprophila rdna transcription unit (1) has been determined. regions coding for 5.8s and 2s rnas have been identified; they are 80 - 90% homologous to the corresponding drosophila sequences and are separated by a 22 nucleotide long spacer. this sequence as well as the two before the 5.8 and after the 2s coding region are very different from the corresponding drosophila sequences. the main features reported in the ... | 1980 | 7433100 |
| the organization of dna in the mitotic and polytene chromosomes of sciara corprophila. | the organization of dna in the mitotic metaphase and polytene chromosomes of the fungus gnat, sciara coprophila, has been studied using base-specific dna ligands, including anti-nucleoside antibodies. the dna of metaphase and polytene chromosomes reacts with at-specific probes (quinacrine, dapi, hoechst 33258 and anti-adenosine) and to a somewhat lesser extent with gc-specific probes (mithramycin, chromomycin a3 and anti-cytidine). in virtually every band of the polytene chromosomes chromomycin ... | 1980 | 6156810 |
| localization of ribosomal dna within the proximal x heterochromatin of sciara coprophila (diptera, sciaridae). | | 1977 | 563785 |
| posttranscriptional modifications of nonhistone proteins of salivary gland cells of sciara coprophila. | | 1977 | 886988 |
| the effect of ecdysterone on nonhistone proteins in salivary gland chromosomes of sciara coprophila. | synthesis and transport of proteins to the cell nucleus during puff induction was studied in s. coprophila. changes in grain distribution along chromosomes (l-methionine [35s] incorporation into protein) were correlated with puffs induced by ecdysterone in vitro; a pattern of specific labelling at the sites of incipient puffs was noted within 2 h after the addition of the hormone, i.e. grains on the chromosomes were in clusters, characteristic for this time point and not seen in the controls (wh ... | 1976 | 1017016 |
| hormone-induced alterations in nonhistone protein. methylation and phosphorylation in sciara coprophila. | methylation and phosphorylation of chromosomal nonhistone protein (nhp) has been demonstrated in the salivary gland cells of diptera [5, 7] and implicated in the control of gene expression [35, 36]. furthermore, hormones can stimulate methyl and phosphoryl side chain metabolism and thus enhance template activity. salivary glands from late fourth instar female larvae of sciara coprophila (cortisone-supplemented and normal diet) were incubated in 3h-uridine (10 muci/ml), 3h-thymidine (10 muci/ml), ... | 1976 | 992241 |
| further studies on the ribosomal rna cistrons of sciara coprophila (diptera). | additional experiments with homologous as well as heterologous hybridization confirmed our previous finding in sciara coprophila that xx females have nearly twice the number of ribosomal rna cistrons as xo males. a comparison between two different x' chromosomes revealed that only the one carrying the irradiation-induced wavy mutation has a deletion of 70% of its ribosomal rna cistrons as compared to the standard x. the deletion is relatively stable, and the remaining ribosomal rna cistrons dono ... | 1976 | 1269920 |
| studies on the fine structure of puffs in sciara coprophila. | | 1974 | 4426215 |
| nucleoprotein methylation in salivary gland chromosomes of sciara coprophila: correlation with dna synthesis. | | 1973 | 4690174 |
| cellular and secretory proteins of the salivary glands of sciara coprophila during the larval-pupal transformation. | the cellular and secretory proteins of the salivary gland of sciara coprophila during the stages of the larval-pupal transformation were examined by electrophoresis in 0.6 mm sheets of polyacrylamide gel with both sds-continuous and discontinuous buffer systems. after sds-electrophoresis, all electrophoretograms of both reduced and nonreduced proteins from single glands stained with coomassie brilliant blue revealed a pattern containing the same 25 bands during the stages of the larval-pupal tra ... | 1972 | 4116523 |
| localization and characterization of the ribosomal rna cistrons in sciara coprophila. | | 1971 | 5091980 |
| extra replications in the "dna-puffs" of sciara coprophila. | | 1968 | 5711091 |
| the role of ecdysone in dna-puff formation and dna synthesis in the polytene chromosomes of sciara coprophila. | | 1968 | 5246561 |
| larval development in sciara coprophila without the formation of chromosomal puffs. | | 1967 | 5233458 |
| observations on spermiogenesis in the fungus gnat sciara coprophila. | although 9-membered centrioles are found in somatic tissues of sciara, the centriole which lies at the spindle pole of the second meiotic division in male sciara is composed of a row of approximately 70 short tubules in an oval array. shortly after telophase of this unequal division, in the daughter cell destined to undergo spermiogenesis, microtubules become confluent with the tubules of the centriole. these tubules have the same density as other cytoplasmic microtubules after glutaraldehyde-os ... | 1966 | 5971003 |
| fine structure of sciara coprophila sperm. | though the fagellum of sciara sperm arises from a blepharoplast and is characterized by doublet tubules with arms, it differs markedly from the familiar type of flagella in the number and arrangement of its tubules. the axial filament complex in sperm from the testis of sciara consists of approximately 70 doublet tubules, each with an associated singlet tubule. near the nucleus these tubules are displaced in an oval array. posteriorly the oval breaks and coils from one free end so that the axial ... | 1966 | 5339379 |
| a study of the nucleolar material in sciara coprophila. | in the polytene chromosomes of sciara coprophila, in addition to a nucleolus, large numbers of nucleolarlike structures or micronucleoli are formed. a detailed mapping localized the nucleolar organizer at one end of the x chromosome and revealed that approximately 18% of the bands of each chromosome are potentially capable of producing micronucleoli. most of these sites are in regions known from a previous study to show asynchronous dna replication: dna puffs and certain heterochromatic regions. ... | 1966 | 5961345 |
| the structure and maturation of the spermatozoa of sciara coprophila. | | 1966 | 5948431 |
| cytoplasmic fine structure of sciara salivary glands. i. secretion. | cells from the anterior segment of the salivary glands of sciara coprophila were found to synthesize and secrete into the gland lumen three morphologically distinct types of granule: 1) a large, electron-lucid granule, up to 1 micro in diameter, staining only faintly with ph 2 fast green and the pas reaction; 2) an ellipsoid granule of moderate density, strongly fast green and pas positive; and 3) a small spherical granule of high electron density. the cells contained numerous golgi areas, up to ... | 1965 | 5328056 |
| glucose-6-phosphatase in the salivary glands of sciara coprophila: a histochemical and biochemical study. | | 1965 | 14330758 |
| culture of insect salivary glands in a chemically defined medium. | a method for culturing the salivary glands of sciara coprophila in a chemically defined medium has been developed. during a 24-hour period, the polytene chromosomes from six larval stages undergo normal developmental mental changes, including puff formation, puff condensation, and dna synthesis. | 1964 | 14202460 |
| cytological and autoradiographic studies in sciara coprophila salivary gland chromosomes. | | 1964 | 14198770 |
| the nature of the influence of x-translocations on sex of progeny in sciara coprophila. | | 1960 | 13813036 |
| further study of the influence of translocations on the sex-determining mechanism in sciara coprophila. | | 1946 | 21020523 |
| sex determination in a "bisexual" strain of sciara coprophila. | | 1938 | 17246881 |
| genetic studies on selective segregation of chromosomes in sciara coprophila lintner. | | 1936 | 17246803 |
| the maturation divisions and fertilization in eggs of sciara coprophila: lint. | | 1932 | 16587692 |