| the 10 kb drosophila virilis 28s rdna intervening sequence is flanked by a direct repeat of 14 base pairs of coding sequence. | most repeat units of rdna in drosophila virilis are interrupted in the 28s rrna coding region by an intervening sequence about 10 kb in length; uninterrupted repeats have a length of about 11 kb. we have sequenced the coding/intervening sequence junctions and flanking regions in two independent clones of interrupted rdna, and the corresponding 28s rrna coding region in a clone of uninterrupted rdna. the intervening sequence is terminated at both ends by a direct repeat of a fourteen nucleotide s ... | 1980 | 6253902 |
| purification and primary structure of metallothioneins induced by cadmium in the protists tetrahymena pigmentosa and tetrahymena pyriformis. | tetrahymena pyriformis and tetrahymena pigmentosa grown in the presence of a non-toxic dose of cadmium, accumulate the metal in the cytosol. purification by gel-permeation, ion-exchange and reverse-phase high-performance liquid chromatography showed that the metal is bound principally to newly formed proteins with ultraviolet spectra and cysteine contents similar to those of cd(2+)-metallothioneins from multicellular organisms. the isolated proteins revealed that the two species of ciliates each ... | 1994 | 7813475 |
| two-dimensional agarose gel electrophoresis as a tool to isolate genus- and species-specific repetitive dna sequences. | two-dimensional electrophoresis in agarose gels separates dna-restriction fragments not only by molecular weight but also according to their at-cluster content. the method produced genus-specific spot patterns of multicopy dna fragments of grains as well as spot patterns of highly repetitive dna fragments of ciliates, demonstrated for barley, spelt, and tetrahymena. further investigations in regard to their specificity by hybridization with three other grain species (wheat, oat, and rye) and thr ... | 2000 | 10933849 |
| species of tetrahymena identical by small subunit rrna gene sequences are discriminated by mitochondrial cytochrome c oxidase i gene sequences. | the mitochondrial cytochrome c oxidase 1 (co1) genes of two isolates of each of the seven mating types of tetrahymena thermophila were sequenced and found to differ by < 1% in nucleotide sequence and to be identical by putative protein sequence. as this gene was highly conserved in this species, the co1 gene sequence was determined for four pairs of tetrahymena species identical in their small subunit rrna gene sequences. the following pairs of species showed from 1% to 12% divergence at the nuc ... | 2006 | 16968457 |
| cloning, characterization, and gene expression analysis of a novel cadmium metallothionein gene in tetrahymena pigmentosa. | a novel cadmium-inducible metallothionein (mt) gene (tpig-mt1) was cloned and sequenced from the ciliate tetrahymena pigmentosa. the number of deduced amino acids is 118. the polypeptide possesses ccc and cc clusters characteristic of typical tetrahymena cd-inducible mts. the structure of tpig-mt1 is different from the reported cd-mt in t. pyriformis, t. thermophila and t. pigmentosa. tpig-mt1 contains two intragenic tandem repeats with 72.9% identity described as tpig-mt1 (repeat a1) and tpig-m ... | 2008 | 18675523 |
| identification, cloning and sequencing of a novel stress inducible metallothionein gene from locally isolated tetrahymena tropicalis lahorensis. | a novel cadmium inducible metallothionein (tmcd1) gene has been identified and sequenced from the locally isolated ciliate, tetrahymena tropicalis lahorensis from industrial effluents. the tmcd1 gene encodes 471 nucleotides, with tga as the stop codon and taa coding for glutamine. this new gene is quite different from the previously reported mt genes in tetrahymena pyriformis and tetrahymena pigmentosa. however, it shows 78% homology with four different cd-mt genes reported from tetrahymena ther ... | 2007 | 17949926 |
| cloning and characterization of a new multi-stress inducible metallothionein gene in tetrahymena pyriformis. | a new multi-stress-inducible metallothionein (mt) gene isoform has been cloned and characterized from the ciliate tetrahymena pyriformis. both the 5'- and 3'-ut regions of the tp-mt2 gene are very different from the previously reported tp-mt1 isoform in this organism and from other described mt genes in tetrahymena pigmentosa and tetrahymena thermophila. the putative protein sequence of tp-mt2 contains cysteine clusters with characteristics of the typical tetrahymena cd-inducible mt genes. howev ... | 2006 | 16621695 |
| [mating types in the ciliate dileptus anser. genetical instability in the mating type system]. | in f1 and f2 from a cross between two clones of dileptus anser isolated from natural sources (mt 1 x x mt iii; mt = mating type), along with "normal" clones, many clones were observed demonstrating abnormal phenotype with respect to the mt-character. irregular features of the latter were as follows: a) a delay in maturation; b) temporary reversion to immature or adolescent state, which means instability of maturity state; c) expression of mt i and mt iii, rather than mt ii as in properly matured ... | 2003 | 14521059 |
| metal interaction and regulation of tetrahymena pigmentosa metallothionein genes. | the patterns of expression of two metallothionein (mt) genes, mt-1 and mt-2, previously identified as cd-mt and cu-mt, were analysed in tetrahymena pigmentosa in response to metal inducers cadmium, copper and zinc and to a mixture of copper and cadmium at appropriate concentrations. co-treatment induces synergistic accumulation of both metals and higher expression of mt-mrnas in the first few hours. mrna levels were observed not to completely correlate with mt-protein levels, suggesting that pos ... | 2002 | 12389817 |
| identification, cloning and characterisation of a novel copper-metallothionein in tetrahymena pigmentosa. sequencing of cdna and expression. | the protist tetrahymena pigmentosa accumulates large amounts of metal ions, particularly cadmium and copper. this capability is linked to the induction of metallothioneins (mts), cysteine-rich metal-binding proteins found in protists, plants and animals. the present study focuses on a novel inducible mt-isoform isolated from tetrahymena after exposure to a non-toxic dose of copper. the cdna sequence was determined utilising the partial peptide sequence of purified protein. the cu-mt cdna encodes ... | 2001 | 11693660 |
| inheritance of the group i rdna intron in tetrahymena pigmentosa. | we have previously argued from phylogenetic sequence data that the group i intron in the rrna genes of tetrahymena was acquired by different tetrahymena species at different times during evolution. we have now approached the question of intron mobility experimentally by crossing intron+ and intron- strains looking for a strong polarity in the inheritance of the intron (intron homing). based on the genetic analysis we find that the intron in t. pigmentosa is inherited as a neutral character and t ... | 1992 | 1499155 |
| cellular uptake and toxicity study of cis-bis(6-aminoquinoline) dichloroplatinum (ii). | a fluorescent analog of cis-diamminedichloroplatinum(ii), cis-bis(6-aminoquinoline)dichloroplatinum(ii), was prepared from k2[ptcl4] and 6-aminoquinoline (aql). hplc of the thiourea derivative of the new complex showed that it has the cis-configuration. the pt-aql complex and the parent ligand aql were evaluated for biological activity and cellular uptake, using the ciliate tetrahymena pigmentosa. the complex was relatively nontoxic at the tested levels below 5 x 10(-4) m, but did exhibit inhibi ... | 1991 | 1880504 |
| genetic instability in the mating type system of tetrahymena pigmentosa. | selfing clones of tetrahymena pigmentosa show several interesting genetic features, and provide some insight into the mechanisms of mating type (mt) determination. they differ significantly from those of tetrahymena thermophila. they are distributed nonrandomly in crosses. their rates of stabilization are highly variable, but most are much lower than those reported for t. thermophila. a number of subclones derived from nearly all the selfers have maintained stable mts in culture for several year ... | 1987 | 3692137 |
| functional intron+ and intron- rdna in the same macronucleus of the ciliate tetrahymena pigmentosa. | diallelic clones of tetrahymena pigmentosa containing equal amounts of intron+ and intron- rdna in the macronucleus were constructed. the macronucleus of the resulting strains divides amitotically during vegetative growth and the diallelic genotype is therefore unstable. the coexistence of the two alleles was followed in the total culture and in single cells during their vegetative segregation and it was observed that replication was non-preferential with respect to the two alleles. the dialleli ... | 1985 | 2986696 |
| mating-type inheritance and maturity times in crosses between subspecies of tetrahymena pigmentosa. | subspecies 6 and 8 of t. pigmentosa (formerly syngens 6 and 8 of t. pyriformis) share a mating-type system controlled by three alleles with "peck-order" dominance at a single locus. the system is apparently closed and limited to three mating types that are homologous, but not identical, in the subspecies. these relationships are reflected in new mating-type designations.-the viability in some intersyngenic crosses is excellent, and the inheritance of major mating types in first-generation hybrid ... | 1980 | 17248998 |
| localization of transcribed regions on extrachromosomal ribosomal rna genes of tetrahymena thermophila by r-loop mapping. | r-loop hybridization and electron microscopy were used to map the rna transcription products of the extrachromosomal rrna genes of tetrahymena thermophila. the mature 17s and 26s rrnas and the nuclear 35s pre-rrna and pre-26s rrna were located with a precision of approximately 100 base pairs. a 370-base pair intervening sequence was found in the 26s coding region. it has the same size and relative location as that found in tetrahymena pigmentosa [wild, m.a. & gall, j.g. (1979) cell 16, 565-573]. ... | 1979 | 291921 |
| an intervening sequence in the gene coding for 25s ribosomal rna of tetrahymena pigmentosa. | an intervening sequence of approximately 400 bp has been discovered in the 25s ribosomal rna gene (rdna) from macronuclei of tetrahymena pigmentosa strain 6um. another strain, 8alp, lacks the intervening sequence in its macronuclear rdna. the presence of the intervening sequence was first suggested by a comparison of the restriction endonuclease maps of the rdna from each strain. a region which differed in size between the two strains was shown to lie within the region coding for 25s ribosomal r ... | 1979 | 455443 |