Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 2020-2024  (7)
  • 1995-1999  (1,124)
  • 1985-1989  (882)
  • 1935-1939  (218)
  • 1890-1899  (35)
Source
Material
Years
Year
Person/Organisation
Keywords
Language
  • 1
    Electronic Resource
    Electronic Resource
    Homozygous deletion of the p16INK4a and the p15INK4b tumour suppressor genes in a subset of human sporadic cutaneous malignant melanoma (1998)
    Oxford BSL : Blackwell Science Ltd
    British journal of dermatology 138 (1998), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Chromosome 9p21 is frequently deleted in malignant melanoma, and one familial malignant melanoma gene has been linked to 9p21–22. Recently, the cyclin D-dependent kinase inhibitors (CDKIs) p16INK4a and p15INK4b have been localized within chromosome 9p21, and the presence of p16INK4a point mutations has been demonstrated in familial melanoma and melanoma cell lines in vitro. To analyse the role of these CDKIs in sporadic human cutaneous non-metastatic malignant melanoma, we examined 36 primary tumour specimens representing different stages of melanoma progression and their corresponding normal skin samples for the three mechanisms of CDKI inactivation described so far. Homozygous codeletion of the p16INK4a and the p15INK4b gene was detected by Southern blot analysis in two tumour samples. By direct sequencing of polymerase chain reaction (PCR)-amplified microdissected genomic DNA, no somatic or germline p16INK4a point mutations or small deletions were detected in the remaining 34 tumour samples; one individual exhibited the previously described germline codon 148 (Ala→Thr) polymorphism. In these tumour specimens, comparative semiquantitative reverse PCR analysis of p16INK4a transcript levels revealed no evidence for repression of p16INK4a gene transcription and thus for p16INK4a promoter inactivation by DNA methylation. These results indicate homozygous p16INK4a and p15INK4b loss to occur in a subset of cutaneous melanomas and suggest, in view of the frequent loss of heterozygosity on chromosome 9p21, the presence of another tumour suppressor gene within this chromosomal region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.1998.02020.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The regulation of enzyme activities of the nicotine pathway in tobacco (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 68 (1986), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The activities of the three enzymes of the route ornithine to the N-methyl-Δ1-pyrrolinium salt and of the eight enzymes of the route quinolinic acid to nicotinic acid (pyridine nucleotide cycle) were determined in the roots of different Nicotiana tabacum L. cultivars and for comparison in tomato (Lysopersicon esculentum L. cv. Vollendung) roots. Enzyme activities were further followed in different plant organs, dedifferentiated tissues, root organ cultures and in the roots after decapitation of tobacco plants. The data are in accord with the concept that the two routes are predominantly regulated by the enzymes putrescine methyltransferase (EC 2.1.1.53) and quinolinic acid phosphoribosyltransferase (EC 2.4.2.19), respectively. Further regulation involves the enzymes NAD+-pyrophosphatase (EC 3.6.1.22) and nicotinic acid mononucleotide glycohydrolase; these findings confirm the suggestion that the transformation to nicotinic acid is performed along two routes: either via the synthesis and degradation of NAD+ or by a direct step through the action of a specific glycohydrolase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1986.tb03415.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Immunoelectron microscopy of Bacillus subtilis cells secreting human interferon α1 or staphylokinase (1989)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 65 (1989), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Post-embedding labelling techniques with colloidal gold-IgG or -protein A complexes were used to determine the subcellular location of IFNα1 and staphylokinase secreted from Bacillus subtilis GB500 cells. Both proteins were present in the cytoplasma and the cell enveloped pointing to a posttranslational mode of translocation across the cytoplasmic membrane. 5- to 10-fold higher concentrations of gold particles per 0.1 μm2 were found on the cell enveloped and clustering was observed suggesting preferential regions for secretion sites. Several control experiments ensured the specificity of the labelling data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1989.tb03683.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Vergiftungen. Giftnachweis (einschl. Blutalkoholbestimmung) (1938)
    Springer
    International journal of legal medicine 29 (1938), S. 171-185 
    Details
    ISSN: 1437-1596
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01767199
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Optimizing area for three-layer knock-knee channel routing (1996)
    Springer
    Algorithmica 15 (1996), S. 495-519 
    Details
    ISSN: 1432-0541
    Keywords: VLSI-design ; Efficient algorithms ; Channel-routing ; Knock-knee mode ; Layer assignment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In this paper we consider the channel-routing problem in the knock-knee mode. An algorithm is presented to construct a layout that is wirable in only three conducting layers. When the channel consists of top-to-bottom nets only, the layout is optimal with respect to the area. In case there are one-sided nets, the algorithm introduces at most one additional column. The algorithm improves all previously known layout algorithms which either use up toN/2 (N number of nets) additional columns to produce a three-layer wirable layout [6], [11], [12] or construct a layout which might not be three-layer wirable [4], [5], [10], [18]. Using a special kind of segment tree as the basic data structure, the algorithm can be implemented to run inO(N logN) time. Previous algorithms with linear running time use either additional columns [6], [12] or solve only special cases [18], [19]. For any layout constructed by the algorithm (or a slightly modified layout) a three-layer assignment can be constructed in timeO(N) with onlyO(N) vias.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01955047
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Heterochronic differences of Hoxa-11 expression in Xenopus fore- and hind limb development: Evidence for lower limb identity of the anuran ankle bones (1998)
    Springer
    Development genes and evolution 208 (1998), S. 175-187 
    Details
    ISSN: 1432-041X
    Keywords: Key words Limb development ; Heterochrony ; Evolutionary innovation ; Hoxa-11 ; Xenopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The wrist (carpus) and ankle (tarsus) of most tetrapods, as well as the wrist of anurans, contains relatively small nodular skeletal elements. The anuran tarsus, however, comprises a pair of long bones, the proximal tarsals tibiale and fibulare, which resemble the lower leg bones, tibia and fibula (zeugopodium). In this paper we investigate whether the proximal tarsals of Xenopus are of zeugopodial character identity, i.e. whether they develop under the influence of the same genes that pattern the lower limb. We compare Hoxa-11 expression in the forelimb bud with that in the hind limb bud by whole-mount in situ hybridization. Hoxa-11 has been implicated in the development of the lower limb. In Xenopus we note three differences between Hoxa-11 expression in fore- and hind limb buds: (1) Hoxa-11 expression is maintained until the hind limb bud reaches a larger size (2 mm) than that of the forelimb bud (1.5 mm); (2) Hoxa-11 expression is maintained over larger spatial domains than in the forelimb; and (3) Hoxa-11 expression has a pronounced posterior polarity in the hind limb, but not in the forelimb. Hind limb expression of Hoxa-11 can be understood as a heterochronic prolonging of the expression dynamic in the forelimb. Finally we found that the proximal tarsals start to develop within the expression domain of Hoxa-11, while in the forelimb the lower arm elements reach the distal expression limit of Hoxa-11. The gene expression data presented here support the notion of a zeugopodial identity of the proximal tarsal elements in Xenopus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050172
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Sites of urokinase-type plasminogen activator expression and distribution of its receptor in the normal human kidney (1996)
    Springer
    Histochemistry and cell biology 105 (1996), S. 53-60 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The urokinase-type plasminogen activator (uPA) is secreted into the urine at high concentrations and both the uPA protein and mRNA are present in human renal tissue. Normal kidney tissue also expresses the receptor for uPA. Neither the precise sites of uPA mRNA expression, nor the distribution of the uPA-receptor antigen, have been elucidated in the human kidney. In the present study, the sites of uPA mRNA expression were identified by in situ hybridization, and the cellular localization of both uPA and uPA-receptor was determined by immunohistochemical analysis. High-level uPA mRNA expression was restricted to epithelial cells of the convoluted proximal tubules and the thick ascending limb of Henle's loop (the straight part of the distal tubule). However, uPA immunoreactivity was not confined to sites of uPA mRNA expression, but was present in all segments of the tubular epithelium. Tubular epithelial cells also exhibited a consistent immunoreactivity with uPA-receptor antibody, indicative of a co-localization of the uPA antigen and its receptor in the uriniferous epithelium. We propose that the uPA antigen expression in nephron segments lacking demonstrable endogenous uPA synthesis may be the result of a uPA-receptor-mediated uptake of uPA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01450878
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Regulation in tobacco callus of enzyme activities of the nicotine pathway (1986)
    Springer
    Planta 168 (1986), S. 402-407 
    Details
    ISSN: 1432-2048
    Keywords: Methylputrescine oxidase ; Nicotiana ; Nicotine biosynthesis ; Ornithine decarboxylase ; Putrescine methyltransferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nicotine synthesis was stimulated by reduction of the medium auxin concentration (induction medium) in callus tissue originating from Nicotiana tabacum cv. Samsun. The enzyme activities of the route ornithine to methylpyrroline, which are those of ornithine decarboxylase, putrescine methyltransferase and methylputrescine oxidase, were determined during callus growth in the induction medium and as a control under non-nicotine-stimulating conditions (growth medium). The enzymes were assayed by high-performance liquid chromatography. Whereas the activities of ornithine decarboxylase were very similar under nicotine-stimulating and non-stimulating conditions, those of putrescine methyltransferase and methyl-putrescine oxidase increased strongly in the induction medium. In addition, the pools of putrescine and methylputrescine were determined throughout the callus growth cycle. Both sets of data strongly confirm the supposition that putrescine methyl-transferase is the enzyme under stringent control for nicotine biosynthesis, whereas the subsequent methylputrescine oxidase is co-regulated, although less stringently.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392368
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The pyridine-nucleotide cycle in tobacco Enzyme activities for the de-novo synthesis of NAD (1985)
    Springer
    Planta 165 (1985), S. 532-537 
    Details
    ISSN: 1432-2048
    Keywords: NAD-synthetase ; Nicotiana (pyridine nucleotides) ; Nicotinic acid mononucleotide adenyltransferase ; Pyridine nucleotide cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The enzyme activities of the pyridine-nucleotide cycle, which transform nicotinic acid mononucleotide (NaMN) into NAD, have been characterized. The investigations were based on the extraction of protein, its purification on disposable gel-filtration columns, and determination of the enzymatic activities by high-performance liquid chromatography techniques. The latter technique avoided the synthesis and use of radioactive precursors. The NaMN-adenylyltransferase which converts NaMN into NaAD (nicotinic acid adenine dinucleotide) and NAD-synthetase which converts NaAD into NAD were characterized by their kinetic parameters and their specific activities in different tobacco tissues. This is the first report on NAD-synthetase from tissue of a higher plant. It was found that NAD-synthetase accepted both glutamine and asparagine for the amide transfer. Adenylyltransfer also occured with nicotinamide mononucleotide (NMN) which was transformed to NAD, whereas the glutamine-dependent amidation was only observed with NaAD. Thus, an additional route for the synthesis of NAD (NaMN→NMN→NAD) obviously does not exist. A comparison of the enzyme activities in tobacco tissues with different capacities for the synthesis of nicotine showed that, in contrast to quinolinic acid phosphoribosyltransferase whose activity was strictly correlated with the nicotine content, only NaMN-adenylyltransferase showed a smooth correlation, whereas NAD-synthetase was not affected at all.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00398100
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The pyridine-nucleotide cycle in tobacco (1986)
    Springer
    Planta 167 (1986), S. 226-232 
    Details
    ISSN: 1432-2048
    Keywords: NAD pyrophosphatase ; Nicotinamidase ; Nicotiana (pyridine-nucleotide cycle) ; Nicotine biosynthesis ; Pyridine nucleotide cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to elucidate the NAD-recycling pathway the following enzyme activities have been characterized in different tobacco tissues and in tomato root: NAD pyrophosphatase, nicotinamide mononucleotide (NMN)/nicotinic acid mononucleotide (NaMN) glycohydrolases, nicotinamidase and nicotinic acid phosphoribosyltransferase. The investigations were performed with protein extracts purified by gel filtration and enzymatic activities were determined by high-performance liquid chromatography methods. The kinetic parameters of the different enzymes from tobacco root and their specificity are reported. The data are in favor of the so-called pyridine-nucleotide cycle VI (NAD→NMN→nicotinamide→nicotinic acid→NaMN→nicotinic acid adenine dinucleotide→NAD). In the nicotine-producing tobacco root a further direct route leading from NaMN to nicotinic acid is proposed. These data are reconciled with the assumption that it is nicotinic acid which is provided by the pyridine-nucleotide cycle for the synthesis of nicotine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391419
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...