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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 54 (1967), S. 251-251 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 10 (1985), S. 103-110 
    ISSN: 1432-0983
    Keywords: Yeast taxonomy ; DNA homologies ; Southern analysis ; Glycolytic gene probes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genePDC1 ofSaccharomyces cerevisiae coding for pyruvate decarboxylase (E.C. 4.1.1.1.) was used as a hybridization probe to detect gene sequence homologies in different strains ofSaccharomyces cerevisiae and in other yeast species. Additionally six other genes coding for glycolytic enzymes as well as the genesURA3 of the pyrimidine synthetic andTRP1 of the tryptophan synthetic pathways were used. A restriction polymorphism for the BamH1 fragments carrying thePDC1 gene was evident within the speciesSaccharomyces cerevisiae. All strains definitely declared asSaccharomyces cerevisiae showed the same restriction patterns. Hybridizations of different intensities were observed only with species in the familySaccharomycetaceae. Hybridizations with different genes showed different degrees of conservation for certain DNA sequences.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 40 (1993), S. 325-335 
    ISSN: 1420-9098
    Keywords: Formicidae ; social parasitism ; PCR ; 18 S ribosomal RNA ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The evolutionary relationship between socially parasitic ants and their hosts is still an unsolved problem. We have compared a 1.2 kb sequence of the 18 S ribosomal RNA genes of the parasitic antsDoronomyrmex kutteri, Harpagoxenus sublaevis andChalepoxenus muellerianus to the sequence of the host speciesLeptothorax acervorum andL. recedens (all subfamily Myrmicinae, tribe Leptothoracini) and to an out-group antCamponotus ligniperda (Formicinae). We found that parasitic species and the host species and alsoCamponotus ligniperda differ at less than 1% of the base positions of the 1.2 kb segment of the 18S rRNA gene. The sequences showed 80.3% identity to the 18 S ribosomal RNA genes of the beetleTenebrio molitor and only 66.5% to that of the dipteranDrosophila melanogaster.
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  • 4
    ISSN: 1420-9098
    Keywords: Formicidae ; Leptothoracini ; Tetramoriini ; internal transcribed spacer ; social parasitism ; evolution ; phylogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A fragment of the internal transcribed spacer (ITS-1) adjacent to the 5.8S rRNA gene of 20 myrmicine ant species was sequenced. Sequence comparisons were carried out between 11 species of the tribe Leptothoracini, five species of the tribe Tetramoriini, three species of the tribe Solenopsidini and one species of the tribe Myrmicini. Additionally, the formicine antCamponotus ligniperda (tribe Camponotini) was analyzed as an outgroup species. Among all investigated species, the fragment had a variable length of ≈ 230–380 bp with only a few conserved sequence elements. The sequences of this fragment were perfectly identical within four palearctic populations ofLeptothorax acervorum indicating that intraspecific variation is rather low. Within the species of Tetramoriini (includingAnergates atratulus) 94.1% of sequence positions were identical, 95.6% within the species of theLeptothorax s.str.-group and 64.6% within the species of theMyrafant-group. Phylogenetic analysis reveals that the social parasitesHarpagoxenus sublaevis, Doronomyrmex goesswaldi, D. kutteri andD. pacis, Chalepoxenus muellerianus as well asStrongylognathus alpinus andTeleutomyrmex schneideri are most closely related to the groups of their respective host species, which generally confirms the taxonomical classifications of the subfamily Myrmicinae based on morphological criteria. The taxonomical positions of the speciesA. atratulus has as yet been uncertain, however, sequence comparison of the ITS-1 fragment leads to the conclusion thatA. atratulus rather belongs to the tribe Tetramoriini than to the Solenopsidini.
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  • 5
    ISSN: 1432-0983
    Keywords: Mammoth ; Cytochrome b ; PCR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 6
    ISSN: 1432-0983
    Keywords: Key words D-ribulose-5-phosphate 3-epimerase ; D-ribose-5-phosphate ketol-isomerase ; Pentose-phosphate pathway ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have cloned and characterized the two remaining unknown genes of the non-oxidative part of the pentose-phosphate pathway of Saccharomyces cerevisiae encoding the enzymes D-ribulose-5-phosphate 3-epimerase (Rpe1p) and D-ribose-5-phosphate ketol-isomerase (Rki1p). Rpe1p has an unexpected high specific activity of 2148 mU × (mg protein)–1 in crude extracts. Deletion mutants of RPE1 show no enzyme activity and are unable to grow on D-xylulose. Unexpectedly, haploid rki1 deletion mutants are not viable. Functional expression of RKI1 was demonstrated following an increase of gene dosage in the haploid rki1 deletion mutant, which restored viability and specific D-ribose-5-phosphate ketol-isomerase activity. Both enzymes show high similarity to the deduced protein sequences of various open reading frames, expressed sequence tags or cDNAs from different organisms.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 547-551 
    ISSN: 1432-0983
    Keywords: MAL regulatory loci ; Segregation analysis ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary By hybridization with a putative MAL2p regulatory sequence we have identified a 19 kb long BamH1 DNA fragment to contain the MALp sequence in a MAL4 strain. A mixture of recombinant plasmids was prepared by ligation of purified 19 kb BamH1 fragments partially digested with Sau3A into the multicopy vector YEp1357. The source of DNA was a strain carrying the MAL4 locus. Yeast maltose non-fermenting strains were transformed with the plasmid mixture. A recombinant plasmid, pRM-4, containing the MAL4p regulatory gene was isolated that complements the maltose-negative phenotype. The plasmid was shown to confer the ability to synthesize maltase to recipient strains grown under inducing as well as under repressing conditions. The MAL4p regulatory sequence cloned was used as a probe in hybridization experiments to study the degrees of homology between the different MAL regulatory genes. The results showed that the sequence from MAL4 strains is strongly homologous to that of MAL3 strains whereas it shows significant differences to the ones of MAL1 and MAL2 strains. Southern analysis of the segregants of crosses between maltose-positive strains and ma10 strains allowed us to localize the maltase regulatory sequence of each MAL locus within a characteristic BamH1 fragment of genomic DNA hybridizing to the isolated sequence.
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  • 8
    ISSN: 1432-0983
    Keywords: Leptothoracini ; Social parasitism ; Cytochrome b ; mtDNA ; PCR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the tribe Leptothoracini, the phylogenetic relationship of socially parasitic ants (Doronomyrmex kutteri, D. goesswaldi and Harpagoxenus sublaevis) and their host species Leptothorax acervorum has been controversial. Even more controversial is the relationship between the socially parasitic ant Chalepoxenus muellerianus and its host species Leptothorax unifasciatus, L. nigriceps, L. interruptus and L. recedens. On the basis of morphological, ecological and ethological criteria it has been argued that socially parasitic ants and their respective hosts always evolved from common ancestors, and hence it has been postulated that these species should be included in common taxonomical groups. This would require the division of the tribe Leptothoracini into two subgroups, one comprising the subgenus Leptothorax (s. str.) and the other the subgenus Myrafant, together with their respective parasitic genera. We have used the polymerase chain reaction (PCR) to compare a 360-bp sequence of the mitochondrial cytochrome b gene of 14 species belonging to the tribe Leptothoracini and an outgroup species Tetranorium impurum (Tetramoriini). The results generally agree with the morphological studies which suggest that a common ancestral species differentiated into host and parasite species. This relationship is very obvious within the Leptothorax (s. str.) group but less pronounced in the species belonging to the Myrafant group. Leptothorax (Temnothorax) recedens shows a greater sequence divergence than the outgroup species T. impurum.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 539-545 
    ISSN: 1432-0983
    Keywords: Maltose fermentation ; Regulatory sequence ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Yeast genomic libraries containing the MAL1, MAL2-8 c and MAL3 loci were used to transform Ma10 strains to a maltose-positive phenotype. A plasmid called pRM-2 was isolated. mal0 strains synthesized alpha-glucosidase when transformed with this plasmid. Specific activities in the range of 500–1,000 mU/mg protein were detected. An increase of 2–3fold could be observed when the isolated sequence was subcloned in the yeast multicopy vector YEp 1357. Plasmid pRM-2 contains a maltase regulatory sequence as demonstrated by its ability to transform a maltose-negative regulatory mutant to a maltose-positive phenotype. That result also indicated that the mal0 recipient strains are defective in the regulatory gene. Hybridization experiments of genomic EcoRl digests to the isolated plasmid pRM-2 showed characteristic EcoRl fragments in all maltose fermenting strains. Some of the fragments are lacking in the ma10 strains suggesting that the regulatory sequence is located in these fragments. BamHl genomic fragments hybridizing to pRM-2 had different sizes for strains containing different MAL loci. Stable transformants which had integrated pRM-2 either in the TRP1 locus or in the MAL2 locus were obtained. The isolation of the latter type indicates that the cloned sequence is homologous to that present at the MAL2 locus.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 50 (1963), S. 625-625 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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