ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Angiosperms
  • Evolution
  • Springer  (25)
  • National Academy of Sciences
  • Periodicals Archive Online (PAO)
  • 1995-1999
  • 1985-1989
  • 1980-1984  (25)
  • 1982  (25)
Collection
Publisher
  • Springer  (25)
  • National Academy of Sciences
  • Periodicals Archive Online (PAO)
Years
  • 1995-1999
  • 1985-1989
  • 1980-1984  (25)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 19 (1982), S. 20-27 
    ISSN: 1432-1432
    Keywords: GU base pairing ; RNA replication ; Globular proteins ; Genetic code ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary It has previously been shown that the formation of GU base pairs in RNA copying processes leads to an accumulation of G and U in both strands of the replicating RNA, which results in a non-random distribution of base triplets. In the present paper, this distribution is calculated, and, using the χ2-test, a correlation between the distribution of triplets and the amino acid composition of the evolutionarily conservative interior regions of selected globular proteins is established. It is suggested that GU wobbling in early replication of RNA could have led to the observed amino acid composition of present-day protein interiors. If this hypothesis is correct, the GU wobbling must have been very extensive in the imprecisely replicating RNA, even reaching values close to the critical for stability of its double-helical structure. Implications of the hypothesis both for the evolution of the genetic code and of proteins are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-1432
    Keywords: Archaebacteria ; Taxonomy ; Evolution ; DNA ; 16S rRNA ; Hybridization ; Phylogeny ; Thermoproteales
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary DNAs from 16 species of archaebacteria including 6 novel isolates were hybridized with 16S rRNAs from 7 species representing different orders or groups of the urkingdom of archaebacteria. The yields, normalized for the number of genes perµg of DNA, and the temperature stabilities of all hybrids were determined and related to each other. A taxonomic tree constructed from such fractional stability data reveals the same major divisions as that derived from comparative cataloging of 16S rRNA sequences. The extreme halophiles appear however as a distinct order besides the three known divisions of methanogens. The methanogens, the halophiles andThermoplasma form one of two clearly recognizable branches of the archaebacterial urkingdom. The order represented bySulfolobus and the related novel orderThermoproteales form the other branch. Three novel genera,Thermoproteus, Desulfurococcus and the “stiff filaments” represent three families of this order. The extremely thermophilic methanogenMethanothermus fervidus belongs to theMethanobacteriales. SN1, a methanogen from Italy, appears as another species of the genusMethanococcus. Another novel methanogen, M3, represents a genus or family of the orderMethanomicrobiales.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 19 (1982), S. 80-86 
    ISSN: 1432-1432
    Keywords: Microtubules ; Tubulin ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Tubulin subunits have been isolated from a variety of protists and marine invertebrates. The sources were: sperm tails of a tunicate (Ciona intestinalis), an abalone (Haliotis rufescens) and a sea anemone (Tealia crassicornis), the gill cilia of a clam (Mercenaria mercenaria), the cilia of a ciliate (Tetrahymena pyriformis) and the cytoplasm of a slime mold (Physarum polycephalum). All the β-tubulins, as characterised by their electropherograms after limited proteolytic cleavage withStaphylococcus aureus protease, were fairly similar. In contrast, two markedly different peptide patterns were found for the α-tubulins of (a) metazoan axonemes and (b) protistan axonemes, plant axonemes and slime mold cytoplasm. Metazoan axonemal α-tubulin peptide patterns could be further divided into two similar but distinct subtypes which did not correlate with the taxonomic divisions of deuterostomia and protostomia, or to different tubulins within an axoneme, or to different tubulins of flagella and cilia. We have postulated that these small differences may be accounted for by a simple glutamicaspartic acid exchange at a particular position in the α-tubulin sequence. Identical peptide patterns were observed for sea urchin and sea anemone sperm tail tubulins, proving that the metazoan type of axonemal tubulin arose before the divergence of bilateral and radial symmetric organisms. The close similarity of the slime mold cytoplasmic α-tubulin peptide pattern to protistan and plant axonemal α-tubulin patterns suggests that the same type of tubulin might be used to form both axonemal and cytoplasmic types of microtubules in protists and plants. The large structural constraints imposed upon this tubulin molecule probably allowed very little change in its primary structure, thus explaining the similarity of tubulins from organisms which diverged at such an early time in eukaryote history. Duplication and modification of the tubulin gene may then have led to the development of specific axonemal and cytoplasmic microtubules during the evolution of the metazoa.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 18 (1982), S. 287-292 
    ISSN: 1432-1432
    Keywords: Evolution ; Endosymbiosis ; Gene transfer ; Transmembrane movement of proteins ; Receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the origin of the mitochondrion and plastid, gene transfer from the ancestral endosymbiont to the host was proposed to be a crucial event. For this genic integration to proceed, products of transferred genes had to return to and enter the endosymbionts. The limiting event was the crossing of the barrier presented by the two semipermeable membranes bounding the proto-organelle. In this paper it is suggested that spontaneous transport allowed transferred gene encoded proteins to enter the endosymbionts before receptors evolved. The effects of these events, including the degeneration of the endosymbiont genome, are discussed. Although the presumed gene transfer had profound effects on the metabolic relationships between host and endosymbionts it probably cannot account for all examples of organelle/cytoplasmic isozyme pairs or the absence of amino acid synthetic enzymes in animal cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-072X
    Keywords: Glycogen ; Archaebacteria ; Thermoacidophiles ; Sulfolobus ; Thermoproteales ; Glucosyl transferase ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Glycogen has been found in thermoacidophilic archaebacteria of the genera Sulfolobus, Thermoproteus, Desulfurococcus and Thermococcus. Thermoplasma acidophilum yielded a related, though less defined compound. Glycogen was identified by elementary analysis, infrared spectroscopy, the nature of the hydrolysis products, the iodine reaction, and the nature of the products of periodate oxydation and reduction. The average chain length was 7. From crude extracts of Sulfolobus and Thermoproteus complexes of glycogen with 4 respectively 2 proteins have been isolated by CsCl density gradient centrifugation. In either case, one of the proteins was identified as glucosyl transferase. The glucosyl transferase of Sulfolobus acidocaldarius strain B 12 utilizes UDP-glucose as well as ADP-glucose as substrates, with K m values of 0.42 and 0.2 mM respectively and turnover numbers of 4.6 and 5.2 per second respectively. In electron micrographs the isolated glycogen protein complex appears as scale like aggregates, whereas in cell sections amorphous bodies fill large portions of the cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of mathematical biology 14 (1982), S. 327-353 
    ISSN: 1432-1416
    Keywords: Evolution ; Molecular evolution ; Dynamical system ; Neo-Darwinian evolution ; Non-Darwinian evolution ; Neutral theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract In order to understand generally how the biological evolution rate depends on relevant parameters such as mutation rate, intensity of selection pressure and its persistence time, the following mathematical model is proposed: dN n (t)/dt=(m n (t-μ)N n (t)+μN n-1(t) (n=0,1,2,3...), where N n (t) and m n (t) are respectively the number and Malthusian parameter of replicons with step number n in a population at time t and μ is the mutation rate, assumed to be a positive constant. The step number of each replicon is defined as either equal to or larger by one than that of its parent, the latter case occurring when and only when mutation has taken place. The average evolution rate defined by $$\upsilon _\infty \equiv {\text{ lim}}_{t \to \infty } \sum _{n = 0}^\infty nN_n (t)/t\sum _{n = 0}^\infty N_n (t)$$ is rigorously obtained for the case (i) m n (t)=m n is independent of t (constant fitness model), where m n is essentially periodic with respect to n, and for the case (ii) $$m_n (t) = {\text{ }}s( - 1)^{n + [1/\tau ]} $$ (periodic fitness model), together with the long time average m ∞ of the average Malthusian parameter $$\bar m \equiv \sum _{n = 0}^\infty m_n (t)N_n (t)/\sum _{n = 0}^\infty N_n (t)$$ . The biological meaning of the results is discussed, comparing them with the features of actual molecular evolution and with some results of computer simulation of the model for finite populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 61 (1982), S. 73-79 
    ISSN: 1432-2242
    Keywords: Nicotiana ; Chloroplast DNA ; Restriction fragments ; Deletion ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nicotiana chloroplast genomes exhibit a high degree of diversity and a general similarity as revealed by restriction enzyme analysis. This property can be measured accurately by restriction enzymes which generate over 20 fragments. However, the restriction enzymes which generate a small number (about 10) of fragments are extremely useful not only in constructing the restriction maps but also in establishing the sequence of ct-DNA evolution. By using a single enzyme, Sma I, a elimination and sequential gain of its recognition sites during the course of ct-DNA evolution is clearly demonstrated. Thus, a sequence of ct-DNA evolution for many Nicotiana species is formulated. The observed changes are all clustered in one region to form a “hot spot” in the circular molecule of ct-DNA. The mechanisms involved for such alterations are mostly point mutations but inversion and deficiency are also indicated. Since there is a close correlation between the ct-DNA evolution and speciation in Nicotiana a high degree of cooperation and coordination betwen organellar and nuclear genomes is evident.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 61 (1982), S. 161-169 
    ISSN: 1432-2242
    Keywords: Cultivated potato ; Evolution ; Parallel spindles ; 2n gametes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A high gene frequency for ps (parallel spindles) is expected in cultivated tetraploid potatoes, S. tuberosum Group Tuberosum, if 2n pollen produced by ancestral diploid plants which were psps was involved in the origin and evolution of the potato. Fifty-six North American cultivars (varieties and advanced selections) were pollinated by diploid clones, either W 5295.7 or W 5337.3 which are homozygous recessive for ps. The segregation ratios in regard to 2n pollen production in derived tetraploid progenies, from 4x×2x crosses, reveal the genotype of ps in the cultivars. Microsporogenesis of 2n pollen producing 4x progeny was observed to avoid an overestimation of the frequency of 2n pollen producing plants due to mechanisms other than parallel spindles. More than 50% of the 56 cultivars are simplex (Pspspsps), since in each of these cultivars about 50% of their progeny produced 2n pollen. The ps gene frequency in the 56 cultivars was estimated as high as 0.69. The high frequency of ps in the tetraploid cultivars clearly supports the hypothesis that 2n pollen produced by plants homozygous recessive for ps have been involved in the origin of cultivated tetraploid potatoes, since a higher frequency of ps in the tetraploid than in the ancestral diploid population can be expected from sexual polyploidization but not from somatic doubling. The importance of meiotic mutants such as ps for the successful evolution of polysomic polyploids is emphasized.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 61 (1982), S. 305-314 
    ISSN: 1432-2242
    Keywords: Arachis ; Karyomorphology ; D2 analysis and genetic distance ; Evolution ; Crop improvement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The chromosome complements of 12 taxa in section Arachis were karyotypically and meiotically analysed. In taxa with 2n=20 the arm ratio of the respective pair of chromosomes was taken as an independent quantitative character and statistically analysed by Mahalanobis D2. Two clusters were formed, one represented solely by A. batizocoi and the other consisting of the remaining 11 taxa. This grouping was confirmed by canonical analysis. In the larger group of species, A villosa and A. correntina were closely related karyotypically and on D2 distance, while A. cardenasii forms a distinct subgroup. A. cardenasii lacks the short “A” chromosome recorded in other species of this group, and A. batizocoi is no longer the only species to have a pair of chromosomes with a secondary constriction. The taxa with 2n=40, A. monticola and A. hypogaea, are karyotypically very similar, though there is a difference in the number of chromosome pairs with a secondary constriction. On the basis of karyomorphological affinity, especially in relation to marker chromosomes, A. cardenasii is probably one of the ancestors of the tetraploid species studied.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 61 (1982), S. 91-95 
    ISSN: 1432-2242
    Keywords: Complement fractionation ; Excess sporads ; Diploid orchid species ; Phaius tribe ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Four out of 10 diploid orchid species showed “complement fractionation” a complex cytological phenomenon, hitherto reported only in polyploid plants. The manifestation of this phenomenon during meiosis is the formation of chromosome subgroups resulting eventually in cells with more than the usual four sporads; five or six being the optimum number in the investigated orchid species. No implications whatsoever can be deduced as to the genetic or genomic constitution of the end products. The presence of the phenomenon in these orchid species could perhaps indicate a polyploid ancestry or concealed hybridity. The operation of “complement fractionation”, however, could be interpreted as an alternative evolutionary pathway opposed to polyploidy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 63 (1982), S. 349-360 
    ISSN: 1432-2242
    Keywords: Chromosomes ; Nucleotides ; Evolution ; Polyploids ; Triticum ; Heterochromatin ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nature of genome change during polyploid evolution was studied by analysing selected species within the tribe Triticeae. The levels of genome changes examined included structural alterations (translocations, inversions), heterochromatinization, and nucleotide sequence change in the rDNA regions. These analyses provided data for evaluating models of genome evolution in polyploids in the genus Triticum, postulated on the basis of chromosome pairing at metaphase I in interspecies hybrids. The significance of structural chromosome alterations with respect to reduced MI chromosome pairing in interspecific hybrids was assayed by determining the incidence of heterozygosity for translocations and paracentric inversions in the A and B genomes of T. timopheevii ssp. araraticum (referred to as T. araraticum) represented by two lines, 1760 and 2541, and T. aestivum cv. Chinese Spring. Line 1760 differed from Chinese Spring by translocations in chromosomes 1A, 3A, 4A, 6A, 7A, 3B, 4B, 7B and possibly 2B. Line 2541 differed from Chinese Spring by translocations in chromosomes 3A, 6A, 6B and possibly 2B. Line 1760 also differed from Chinese Spring by paracentric inversions in arms 1AL and 4AL whereas line 2541 differed by inversions in 1BL and 4AL (not all chromosomes arms were assayed). The incidence of structural changes in the A and B genomes did not coincide with the more extensive differentiation of the B genomes relative to the A genomes as reflected by chromosome pairing studies. To assay changing degrees of heterochromatinization among species of the genus Triticum, all the diploid and polyploid species were C-banded. No general agreement was observed between the amount of heterochromatin and the ability of the respective chromosomes to pair with chromosomes of the ancestral species. Marked changes in the amount of heterochromatin were found to have occurred during the evolution of some of the polyploids. The analysis of the rDNA region provided evidence for rapid “fixation” of new repeated sequences at two levels, namely, among the 130 bp repeated sequences of the spacer and at the level of the repeated arrays of the 9 kb rDNA units. These occurred both within a given rDNA region and between rDNA regions on nonhomologous chromosomes. The levels of change in the rDNA regions provided good precedent for expecting extensive nucleotide sequence changes associated with differentiation of Triticum genomes and these processes are argued to be the principal cause of genome differentiation as revealed by chromosome pairing studies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 139 (1982), S. 209-227 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Dicotyledons ; Monocotyledons ; DNA reassociation kinetics ; fast repeats ; repetitive DNA ; single copy DNA ; short period interspersion pattern ; slow repeats ; genome evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Angiosperms investigated by DNA/DNA reassociation studies were classified and tested for a taxonomic class- and subclass-specifity in a biometrical fashion. Monocotyledons and Dicotyledons differ significantly from each other with respect to a genomic parameter (U/R-ratio;U single copy DNA fraction;R = 1-U fraction of repetitive DNA). This difference is discussed from an evolutionary and molecular point of view.—Intercorrelations between the fraction of fast repeats, slow repeats, and single copy DNA can be detected. The amount of DNA organized in a short period pattern of interspersion is found to depend on the fraction of repetitive and single copy DNA. The number of DNA segments tandemly arranged in a short period pattern is linearly correlated withR/U-values. This correlation allows for a formula suitable for the estimation of the number of active genes in angiosperms. The analytical complexities of repetitive and single copy DNA are linearly correlated with the genome size of higher plants. The ratioU/R depends on the genome size of angiosperms in a hyperbolic fashion.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 139 (1982), S. 163-178 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliaceae ; Tulipa subg.Leiostemones ; Giemsa banding ; heterochromatin ; karyosystematics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The chromosomes of several cultivatedTulipa species of subg.Leiostemones were examined in conventionally stained and C-banded preparations. The heterochromatin content varied from almost none to 45%. Several chromosome types were recognized with respect to chromosome morphology and heterochromatin distribution, and groups of species with common chromosome characteristics could be identified. These karyological relationships are discussed with respect to the groups formed on the basis of floral and bulb charateristics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 140 (1982), S. 39-55 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Brassicaceae (Cruciferae) ; Alysseae ; Arabideae ; Brassiceae ; Heliophileae ; Hesperideae ; Lepidieae ; Pringleeae ; Sisymbrieae.—Serological systematics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The serological investigations support the opinion ofJanchen (1942) to combine the generaBunias, Isatis, andSisymbrium in the tribeSisymbrieae; Cheiranthus, Erysimum, andMatthiola in the tribeHesperideae; andBrassica, Crambe, Sinapis, andSuccowia in the tribeBrassiceae. They further underline the central position of theSisymbrieae and the isolated position of theHeliophileae. In accordance withEigner (1973) theBrassiceae are placed closer to theSisymbrieae than inJanchen; the same holds for thePringleeae. No serological justification could be found to uniteArabis andBarbarea in the tribeArabideae, andAlyssum andLunaria in theAlysseae. From the antigen-systems used among the representatives ofJanchen's Lepidieae the generaLepidium andNeslia show remarkable correspondence both toCamelina andThlaspi, but not toCochlearia which appears distant fromCamelina andThlaspi also.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 140 (1982), S. 109-117 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Gramineae (Poaceae) ; Agrostis tenuis.—Evolution ; Copper tolerance ; genotype-environment interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of increased copper concentration in solution on the rooting of seven copper tolerant populations ofAgrostis tenuis has been examined using the regression technique ofFinlay &Wilkinson (1963). Three types of response to increased copper concentration have been detected, and it is suggested that these reflect a different genetic control of copper tolerance in different populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    ISSN: 1615-6110
    Keywords: Angiosperms ; Boraginaceae ; Symphytum.—Pyrrolizidine alkaloids ; chemotaxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By means of thin layer chromatography in conjunction with mass spectrometry the pyrrolizidine alkaloid patterns derived fromSymphytum asperum, several cytotypes ofS. officinale agg. and the artificial hybrids of the former taxa, were compared. The obtained patterns were not essentially affected by variation in cytotype, harvesting times and -location of plants. Lycopsamine, acetyl-lycopsamine and symphytine or their isomers were generally found in theS. officinale cytotypes, echimidine and symphytine inS. asperum. The interspecific hybrids contained all alkaloids mentioned. The definite lack of echimidine in the 2 n=40 cytotype proves that it is conspecific withS. officinale and does not belong to a hybrid-swarmS. asperum × S. officinale with 2 n=48.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 141 (1982), S. 143-152 
    ISSN: 1615-6110
    Keywords: Bacillariophyta ; Bacillariaceae ; Nitzschia ; Raphe Structure ; Systematics ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The use of the central raphe endings as a key character in the classification ofNitzschia is argued to be of doubtful validity. Some aspects of the evolution of the raphe are discussed in relation to variation in raphe structure within fibulate genera.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 112 (1982), S. 26-36 
    ISSN: 1615-6102
    Keywords: Aneilema ; Commelina ; Cytochemistry ; Evolution ; Papillae ; Pollination ; Secretion ; Stigmas ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The stigmas of species inAneilema andCommelina are trifid and comprise elongate papillae. Progressive degeneration of papular cells is observed in stigmas from open flowers and at anthesis papillae may be moribund and collapsed. Fluid emanating from the hollow style flows onto the surface through ruptures in the cuticle at the interpapillar junctions into the interstices at maturity. This secretion stains positively for protein. Stigmas are of the “wet” type. The cuticle overlying the papillar cells is ridged and at the final stages prior to flowering this cuticle becomes detached from the underlying cellulosic wall. The sub-cuticular space so formed is filled with secretion. InAneilema species detachment of cuticle is at the papillar tip and along the lateral walls. InCommelina species the anticlinal walls of adjacent papillae are strongly attached for much of their length and thus detachment of cuticle is restricted to the papillar tip. The cell wall at the tip in both genera may proliferate forming a rudimentary transfer-cell type wall. The secretion is considered to be produced by the papillar cells. It is PAS positive but fails to stain for protein and in both the light and electron microscopes appears heterogenous. Pollen attachment, hydration, germination and early tube growth are very rapid following self-pollination, the pollen tubes entering the neck of the style within ten minutes of attachment. A unique character combination involving pollen and stigmas in these genera indicates a monophyletic origin.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 139 (1982), S. 319-322 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Scrophulariaceae ; Euphrasia ; E. alpina ; E. ×dilata ; E. hirtella ; E. kerneri ; E. picta ; E. rostkoviana ; E. tricuspidata ; E. ×trikoviana ; E. ×vestinensis ; hybrids ; chromosome numbers ; Flora of Italy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The following new hybrids are described:Euphrasia ×dilata = E. hirtella Jordan exReuter ×alpina Lam.;Euphrasia ×trikoviana = E. tricuspidata L. ×rostkoviana Hayne. The chromosome number ofEuphrasia tricuspidata L. has been established for the first time: 2n = 22.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 140 (1982), S. 75-86 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Brassicaceae ; Matthiola incana.—DNA interspersion pattern ; Messenger RNA ; RNA complexity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The DNA of the cruciferMatthiola incana (Brassicaceae, Capparales) has been investigated for the pattern of sequence interspersion and RNA transcription. A short period pattern of interspersion (Xenopus-like interspersion pattern) is predominant (60%). Similar to a series of other Angiosperms (tobacco, soybean, parsley and some cereals) repetitive clusters orinter-se interspersion patterns of repetitive DNA occur inMatthiola genome and amount to 12%. From the hybridization of single copy DNA with poly(A)−-RNA and from cDNA/poly(A)+-RNA and cDNA/poly(A)−-RNA hybridizations a number of about 9,400 active genes can be estimated forM. incana seedlings. Both RNA constituents (poly(A)+-RNA and poly(A)−-RNA) contain mainly the same protein-coding mRNA sequences. Total mRNA is amounting to about 4% of theM. incana RNA population. A total of 1.2% (or about 30% of mRNA) of theM. incana RNA is represented by polyadenylated mRNA sequences. About 3.6% of single copy DNA hybridizes with poly(A)−-RNA. Approximately 7% of theM. incana genome, organized in a short period pattern of DNA sequence interspersion, is transcribed into RNA sequences (mRNA). About 6% of clustered repetitive DNA is expressed into RNA sequences such as rRNA and tRNA. Approximately 1.6 × 106 rRNA, 1.75 × 107 tRNA and 3.7 × 105 mRNA molecules are present perMatthiola seedling cell. The transcription rate of single rRNA and tRNA genes can be estimated to be about 1,400 or 1,100 copies per gene, respectively.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 140 (1982), S. 141-149 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Malvaceae ; Gossypium hirsutum ; G. ramondii ; G. herbaceum ; G. arboreum.—Allopolyploidy ; alcohol dehydrogenase ; developmental homeostasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Electrophoretic variation in alcohol dehydrogenase (ADH) was examined in tetraploidGossypium hirsutum and its putative diploid progenitorsG. ramondii, G. herbaceum, and a close relative,G. arboreum. All the diploids had three isozymes, while strains of the tetraploidG. hirsutum had either 4 or 6. Each isozyme was eluted from starch gels and significant differences in activity were noted between several of the isozymes relative to pH, substrate, temperature and salinity. This suggests that an increase in enzyme heterozygosity can result in higher levels of developmental homeostasis, but it depends on the isozyme alleles involved.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 140 (1982), S. 179-189 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliaceae s. 1. ; Alliaceae ; Allium ampeloprasum agg. ; A. commutatum ; A. bourgeaui, A. porrum.—Karyosystematics ; Karyotype differentiation ; chromosome polymorphism ; B-chromosomes ; polyploidy —Flora of the Mediterranean. Aegaean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chromosome numbers (2×, 3×, 4×), B-chromosomes, and variation among marker chromosomes inAllium commutatum Guss. was studied. These different chromosomal types exhibit distinct distribution patterns and a centre of variation has been located in the central Aegean area. A common origin ofA. commutatum, the Aegean endemicA. bourgeaui Rech. fil.,A. ampeloprasum L. and the cultivatedA. porrum L. is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 140 (1982), S. 225-234 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Linaceae ; Linum sect.Linopsis—Evolution ; classification ; chromosome numbers ; heterostyly ; pollen morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract SectionLinopsis of the genusLinum is the largest and probably the most widespread of the five commonly recognized sections. Using a number of traits, but especially heterostyly, style union, development of false septa in the fruit, pollen morphology, and chromosome number, together with petal pigmentation, number of floral parts, and stigma shape, the section is divided into five subsections:Dichrolinum, with one series;Halolinum with one;Linopsis, with four;Keniense, with one; andRigida, with two. Of these, subsect.Keniense and two series are new, the remaining four subsections and four series are published in a new rank. The inferred relationships of all of the groups and the general distribution of each are discussed. The section ranges from southern Europe and the Mediterranean region to India, eastern and southern Africa and throughout much of North and South America. The primitive species of the section are believed to be in the Mediterranean region.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 141 (1982), S. 7-21 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Acanthaceae ; Asteraceae ; Cistaceae ; Brassicaceae ; Cucurbitaceae ; Euphorbiaceae ; Juncaceae ; Lamiaceae ; Linaceae ; Lythraceae ; Nyctaginaceae ; Plantaginaceae ; Poaceae ; Podostemaceae ; Polemoniaceae ; Scrophulariaceae ; Solanaceae ; Urticaceae ; Zygophyllaceae ; Mucilage content of myxospermatic diaspores ; extraction procedures ; swelling factors ; substructures of mucilages
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mucilage content of structurally differing myxospermatic diaspores from 49 species belonging to 19 families ofAngiospermae has been determined by applying various extraction procedures. The results demonstrate no obvious relationship between the size, mucilage quantity, and the swelling factor of the diaspores studied. Furthermore, mucilage producing structures and structural peculiarities of the mucilages themselves are elaborated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 224 (1982), S. 117-128 
    ISSN: 1432-0878
    Keywords: Endocrine pancreas (alligator) ; Endocrine cells ; Peptidergic nerves ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemical methods for light and electron microscopy were used to demonstrate the regulatory peptides present in the endocrine pancreas of thealligator, Alligator mississippiensis.The peptides studied included insulin, glucagon (pancreatic and enteric), somatostatin, pancreatic polypeptide (avian, bovine and human), vasoactive intestinal polypeptide, substance P, metenkephalin, β-endorphin, C-terminal gastrin/CCK and gastric inhibitory polypeptide. Endocrine cells were detected using antisera to insulin, pancreatic glucagon, somatostatin and avian pancreatic polypeptide, whereas peptidergic nerves were stained with antisera to vasoactive intestinal polypeptide. All other antisera were unreactive in the alligator pancreas. The peptide-containing structures were identified ultrastructurally by both the semithin/thin and immuno-gold methods. The results showed that five of the regulatory peptides commonly detected in the mammalian pancreas were immunologically recognisable in the alligator. In addition, the ultrastructural appearance of the peptide-containing cells was clearly distinct from that reported in mammals.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...