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  • Column liquid chromatography  (86)
  • Saccharomyces cerevisiae  (58)
  • Immunocytochemistry  (52)
  • phosphorus  (43)
  • Springer  (239)
  • 1990-1994  (239)
  • 1992  (239)
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  • 1990-1994  (239)
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  • 1
    ISSN: 1420-9055
    Keywords: Sediment ; interstitial water ; phosphorus ; iron ; persulfate digestion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It is shown that sorption of orthophosphate to iron compounds, formed during persulfate digestion, can cause a significant underestimation of total dissolved phosphorus in interstitial waters rich in iron and poor in phosphorus. Labelling the samples with carrier free32PO4 before digestion allows to correct for these losses.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 48 (1992), S. 1162-1164 
    ISSN: 1420-9071
    Keywords: Polygodial ; warburganal ; antifungal activity ; Candida albicans ; Saccharomyces cerevisiae ; Pityrosporum ovale ; enhancing effect ; antioxidants ; vitamin C ; BHA ; anethole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The antifungal activity of two drimane sesquiterpene dialdehydes, polygodial (1) and warburganal (2), alone and in combination with several other substances, was examined against three fungi,Candida albicans, Saccharomyces cerevisiae andPityrosporum ovale employing a broth dilution method. Anethole significantly synergized the activity of the two sesquiterpenoids againstC. albicans andS. cerevisiae however, it had only an, additive effect againstP. ovale. By contrast, two antioxidants, ascorbic acid (vitamin C) and BHA (butylated hydroxyanisole), noticeably enhanced the activity of the sesquiterpenoids againstP. ovale, but had no, effect againstC. albicans andS. cerevisiae.
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  • 3
    ISSN: 1432-1432
    Keywords: Thiolase ; Peroxisome evolution ; Bootstrap analysis ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The thiolase family is a widespread group of proteins present in prokaryotes and three cellular compartments of eukaryotes. This fact makes this family interesting in order to study the evolutionary process of eukaryotes. Using the sequence of peroxisomal thiolase from Saccharomyces cerevisiae recently obtained by us and the other known thiolase sequences, a phylogenetic analysis has been carried out. It shows that all these proteins derived from a primitive enzyme, present in the common ancestor of eubacteria and eukaryotes, which evolved into different specialized thiolases confined to various cell compartments. The evolutionary tree obtained is compatible with the endosymbiotic theory for the origin of peroxisomes.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Microchimica acta 109 (1992), S. 201-209 
    ISSN: 1436-5073
    Keywords: phosphonate base scale inhibitor ; brine ; direct current plasma ; inductively coupled plasma atomic emission spectrometry ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The determination of phosphonate base scale inhibitors in brines by direct current plasma (DCP) and inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The first method is based on a direct nebulization of the brine samples and plasma using the phosphorus line at 213.618 nm. The second method involves extraction of phosphorus as phospho-antimonyl molybdate complex into methylisobutyl ketone (MIBK) phase and analysis of the extract for molybdenum using the Mo 313.260 nm line. Comparison between the proposed methods and an established recommended method [1] shows excellent agreement between the results in addition to the sensitivity and ease of automation provided by AES.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 32 (1992), S. 223-227 
    ISSN: 1573-0867
    Keywords: Soil testing ; phosphorus ; relative yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A greenhouse experiment, with Okra (Abelmoschus esculentus L.) as the test crop, was conducted on twenty-one soils ranging in Olsen's extractable phosphorus from 1.8 to 15.5µg Pg−1 soil. The experiment was conducted at Punjab Agricultural University, Ludhiana, India. The soils were nonsaline with pH ranging from 7.7 to 8.6. A critical level of 2.55µg Pg−1 soil was predicted by Cate and Nelson's (1971) statistical procedure. Because of a wide range in relative yields, this value did not accurately predict response to applied P. An approach to compute minimum response to applied fertilizer, which is likely to be obtained at a particular Olsen P level, has been presented. It involves calculation of lower 60 percent confidence limits for relative yield and fitting loge-linear regression to the transformed data. The regression was tested on a published data set and was found to hold well.
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  • 6
    Electronic Resource
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    Springer
    Nutrient cycling in agroecosystems 32 (1992), S. 259-267 
    ISSN: 1573-0867
    Keywords: Nitrogen ; phosphorus ; timber increment ; fertilization ; Pinus radiata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two trials inPinus radiata growing on different sites in N.S.W. allowed consideration of fertilizer applications after 2nd or 3rd thinning. The trials included factorial applications of N and P at a single thinning intensity plus a further treatment which allowed assessment of different thinning intensities. The most significant growth responses were obtained by application of N and P in combination. The largest response (additional productivity compared with the unfertilized control) occurred 4 years after application and after 7 years there was no additional absolute response for either of the two sites. The largest fertilizer response was 70 m3 ha−1 over 7 years on one site and 36 m3 ha−1 on the other, indicating differences in absolute responses between sites. It was concluded that in planning treatments the most responsive sites near the end of the rotation should be selected to maximise economic returns. Foliage analyses indicated differences between sites at the commencement of the study. It was concluded that either a single year of foliage analyses at study commencement is of value, or sampling every year of the study should be used to analyse responses, but a single year of analysis during or at the end of the study would not be of value.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Antonie van Leeuwenhoek 62 (1992), S. 35-46 
    ISSN: 1572-9699
    Keywords: introns ; pre-mRNA splicing ; RNA processing ; Saccharomyces cerevisiae ; yeast genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The occurrence of introns in nuclear precursor RNAs (pre-mRNAs) is widespread in eukaryotes, and the splicing process that removes them is basically the same in yeasts as it is in higher eukaryotes. Splicing takes place in a very large, multi-component complex, the spliceosome, and biochemical studies have been complicated by the large number of splicing factors involved. This review describes how genetic approaches used to study RNA splicing inSaccharomyces cerevisiae have complemented the biochemical studies and led to rapid advances in the field.
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  • 8
    Electronic Resource
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    Springer
    Aquatic sciences 54 (1992), S. 58-76 
    ISSN: 1420-9055
    Keywords: Eutrophication ; lake management ; phosphorus ; nitrogen ; chlorophyll-a ; slope estimator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We estimate the response of chl-a (mg · m−3) to changes in concentrations of total phosphorus (TP) by calculating the slopeS = Δchl-a/ΔTP in chl-a =f(TP) graphs. Results show that in years where algae are P-limited oligotrophic lakes respond less (median slope 0.21) to changes in nutrient concentrations than eutrophic lakes, (median slope 0.31) and these again less than hypereutrophic lakes, (median slope 1.02). We find no saturation value for the slope within the TP range considered (6–480 mg · m−3). Chl-a in eutrophic lakes responds more frequently to non-nutrient factors than oligotrophic and hypereutrophic lakes. Results obtained by replacing TP with a new nutrient parameter, TP′ = 0.056 · TP · IN0.226, in which inorganic nitrogen, IN, is factored in, suggest that nitrogen has an influence on chl-a in oligotrophic lakes. Blue-green algae respond less to changes in TP than other algal species, e.g., diatoms.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Aquatic sciences 54 (1992), S. 381-390 
    ISSN: 1420-9055
    Keywords: Eutrophication ; phosphorus ; lake restoration ; internal restoration measures for lakes ; Swiss lakes ; Lake Lugano (Lago di Lugano)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In most lakes eutrophication is linked to an excessive input of phosphorus. Lake restoration by reduction of P-input (external measure) has led to a considerable drop of the P-concentration in all major Swiss lakes as well as in many other lakes. Internal restoration measures such as artificial mixing, drainage of hypolimnetic water, flushing, aeration, biomanipulation and others serve to improve and accelerate the response of a lake to external measures. For the case of Lago di Lugano, a simple two-box model is employed to demonstrate that a reduction of the P-input to about 25% of the present values is necessary to reach the “P-criterion” (P-concentration below 30 µg/l). Internal measures could possibly accelerate the extremely slow response of the northern basin.
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  • 10
    ISSN: 1432-041X
    Keywords: Sea urchin ; Jelly coat ; Accessory cell ; Oogenesis ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The immunocytochemical localization of the egg-jelly macromolecule, a fucose sulphate glycoconjugate (FSG) that induces the acrosome reaction in spermatozoa, was investigated in ovaries of the sea urchin Hemicentrotus pulcherrimus by use of a polyclonal antibody. The polyclonal antibody reacted with the accessory cells and oocytes in the ovarian lumen. In the accessory cells, evidence of an intense immunohistochemical reaction was observed in many globules of variable density. Products of the specific immunohistochemical reaction were frequently observed in the surface region of oocytes, at a distance from the ovarian wall. At the ultrastructural level, the polyclonal antibody was found to react with the material present in the vacuole-like structures of the globules in the accessory cells. Many gold particles, demonstrating specific immunolabelling, were associated with well-developed microvilli on the vitellogenic oocytes. In the mature oocytes, intense labelling was observed in the jelly coat but not in the vitelline coat. By contrast, oogonia and early oocytes were barely labelled. Quantitative data indicated that the extent of immunolabellings in the surface region of oocytes was very high in the vitellogenic and mature oocytes. In all cases, neither the oocyte cytoplasm nor the subcellular organelles were labelled. These results suggest that FSG is produced by the accessory cells and is deposited initially on the surface of vitellogenic oocytes for the formation of jelly. These findings may provide a new insight into the role of the accessory cells in the reproductive process of the sea urchin.
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  • 11
    ISSN: 1432-0827
    Keywords: Growth hormone ; Growth hormone receptor ; Odontogenesis ; Bone remodeling ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Growth hormone (GH) may regulate tooth formation and bone remodeling associated with tooth eruption. This study reports the distribution of growth hormone receptor/binding protein in developing rat molars and adjacent alveolar bone by immunocytochemistry using well-characterized anti-growth hormone receptor monoclonal antibodies. These tissues represent an excellent model for studying the ontogenic changes that occur in odontogenic and osteogenic cells, as these cells are found in linear arrays displaying the various stages of morphological and functional differention, and differentiated function. Immunoreactivity was first seen in precementoblasts in contact with the epithelial root sheath, and preodontoblasts. However, growth hormone receptor immunoreactivity was associated primarily with the cytoplasm of odontogenic and osteogenic cells forming their respective matrices. Thus, cementoblasts and odontoblasts at sites of new matrix formation showed intense immunoreactivity whereas cementocytes and mature odontoblasts at later stages of tooth development were nonreactive. Osteoblasts engaged in intramembranous ossification in the alveolar bone were positive, although osteocytes and endosteal cells were immunonegative. Osteoclasts at sites of alveolar bone remodeling resorption were also immunopositive. These patterns of receptor expression parallel the ontogenic sequences of odontogenic and osteogenic cells and suggest that GH promotes the functional state of these cells. Our results also imply that GH may influence differentiation or differentiated functions associated with odontogenesis, osteogenesis, and bone remodeling independent of systemic insulin-like GF-I.
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  • 12
    Electronic Resource
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    Sexual plant reproduction 5 (1992), S. 89-100 
    ISSN: 1432-2145
    Keywords: Actin ; Cytoskeleton ; Generative cell ; Immunocytochemistry ; Microtubule ; Mitosis ; Phragmoplast ; Pollen ; Rhodamine phalloidin ; Sperm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Disagreement has arisen over the presence of actin-containing microfilaments (Mfs) in angiosperm generative cells and sperm (GSP). In order to address this issue, we subjected GSP of Tradescantia virginiana, Nicotiana tabacum and Rhododendron laetum to a series of localizations using different antiactins, rhodamine phalloidin and antimyosin. Coordinate staining with antitubulin and Hoechst 33258 defined the status of the microtubule (Mt) cytoskeleton and stages of generative cell division. Additional experiments utilized cytochalasin D (CD). In no instance could Mfs be detected in GSP of the three species. Instead, Mfs seen at the periphery of GSP appear to be continuous with vegetative Mfs and thus are in the vegetative cytoplasm. Mfs are not seen in the constriction zone of dividing T. virginiana generative cells, nor are they indicated in the phragmoplast of N. tabacum and R. laetum. Myosin localizations reveal punctate staining in the vegetative cytoplasm and a thin line of fluorescence around the the outside of the generative cell. While CD seems to delay generative cell division, cytokinesis still takes place. CD-induced Mf fragments are evident in the vegetative cytoplasm but not in GSP. The weight of evidence therefore indicates that GSP do not contain Mfs. The implications of this conclusion for the behavior of GSP and the mechanism of cytokinesis in dividing generative cells are considerable.
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  • 13
    ISSN: 1432-0983
    Keywords: Trans-kingdom conjugation ; DNA integration ; Saccharomyces cerevisiae ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary IncQ-derived conjugative shuttle vectors, which carried the yeast gene URA3 and/or the yeast autonomously replicating sequence (ARS1), were constructed. Both the ars-plus plasmid pAY205 and the ars-less plasmid pAY201 were successfully transmitted from E. coli to S. cerevisiae by the action of mob and tra. In this trans-kingdom conjugation, plasmid pAY205 could replicate and be retained in transconjugants. Plasmid pAY201 caused the formation of “micro-colonies” of abortive transconjugants due to its transient expression and rapid disappearance. Nevertheless, one per about 103 colonies caused by transmitted pAY201 plasmids were uncurable by integration into the homologous region of a yeast chromosome. Analyses by restriction enzyme mapping and Southern hybridization indicate that this integration is primarily caused by a double crossover during conjugation and not by a single reciprocal recombination.
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  • 14
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Transcriptional activator ; Oxidative stress ; Glutathione
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The PAR1/SNQ3 gene of S. cerevisiae, which increases resistance to iron chelators in multi-copy transformants, is identical to the YAP1 gene, a yeast activator protein isolated as a functional homologue of the human c-jun oncogene by binding specifically to the AP-1 consensus box. The observed H2O2-sensitivity of par1 mutants has been attributed to an increased sensitivity to reduced oxygen intermediates. Accordingly, par1 mutants did not survive an elevated oxygen pressure and were very sensitive to menadione and methylviologene, two chemicals enhancing the deleterious effects of oxygen. The specific activities of enzymes involved in oxygen detoxification, such as superoxide dismutase, glucose 6-phosphate dehydrogenase and glutathione reductase, were decreased in par1 mutants and increased after PAR1 over-expression. As in the case of oxygen detoxification enzymes, the cellular levels of glutathione were similarly affected. These observations indicate that PAR1/YAP1/SNQ3 is involved in the gene regulation of certain oxygen detoxification enzymes. The finding that H2O2 promotes DNA-binding of human c-jun is consistent with a similar function for PAR1/YAP1/SNQ3 and c-jun in cellular metabolism.
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  • 15
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mitochondrial trp-tRNA synthetase ; Nuclear mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The conditional respiratory-deficient Saccharomyces cerevisiae mutant pet-ts2281 was complemented by an yeast genomic DNA library. The gene thus isolated was sequenced and proved to be identical to the known MSW1 sequence encoding mitochondrial tryptophanyl-tRNA synthetase (Myers and Tzagoloff 1985). Compared to the wild-type, the ts2281 mutant allele of MSW1 contained a single T→C transition leading to a Leu→Ser replacement at position 294 of the protein sequence. In addition to this mutational alteration, our sequence data for the wild-type gene differ from the originally published MSW1 sequence at five other DNA positions which affect two locally restricted regions of the polypeptide chain. As expected, at the non-permissive temperature ts2281 cells are specifically defective in mitochondrial trp-tRNA formation and, thus, in overall mitochondrial protein synthesis. In addition, the patterns of cytochrome b mRNA maturation intermediates were distinctly different in ts2281 and wild-type yeast cells. The mutational effect of the observed amino-acid substitution in ts2281 is discussed in terms of weakened hydrogen bonding in the C-terminal half of the MSW1-encoded protein.
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  • 16
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Aminoacyl-tRNA synthetase mutant ; PGK overexpression ; In vivo misreading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hts1.1 temperature-sensitive histidinyl-tRNA synthetase mutation enables Saccharomyces cerevisiae to be starved for His-tRNAHis by upshift to the non-permissive temperature of 38°C. If yeast behaves similarly to bacterial and mammalian cells, this lack of His-tRNAHis should greatly enhance misreading at histidine codons (CAU/CAC) by Gln-tRNAGln, resulting in substitution of the neutral amino acid glutamine in place of histidine, a basic amino acid. Such misreading causes the isoelectric point (pI) of proteins to shift to lower values, and is readily detectable as “stuttering” on two-dimensional (2D) protein gels. By gel analysis of pulse-labelled proteins of hts1.1 yeast cells that were overexpressing phosphoglycerate kinase (PGK), our study sought to detect this specific translational error in PGK protein. It was not detected by this relatively sensitive technique, indicating that missense errors due to glutamine insertion at histidine codons do not occur in yeast at the readily-detectable level found in bacterial and mammalian cells.
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  • 17
    ISSN: 1432-0983
    Keywords: 1,3-β-glucanase genes ; Saccharomyces cerevisiae ; Chromosomal mapping ; Genetic mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The map position of three 1,3-β-glucanase-encoding genes in S. cerevisiae has been determined following conventional meiotic and mitotic mapping combined with recombinant DNA techniques. EXG1, EXG2 and SSG1 were localized to chromosomes XII, IV and XV, respectively, by hybridizing the cloned genes to Southern blots of chromosomes sepaated by pulsed-field gel electrophoresis, in conjunction with the rad52-1-dependent chromosome-loss mapping technique. Meiotic tetrad analyses further localized the EXG1 gene 6.1 centimorgans centromere-proximal to CDC25 on the right arm of chromosome XII. EXG2 was positioned between LYS4 and GCN2 on the right arm of chromosome IV, at distances of 6.2 centimorgans from LYS4 and 4.9 centimorgans from GCN2. Finally, the SSG1 locus mapped on the right arm of chromosome XV, about 8.2 centimorgans to the centromere-proximal side of HIS3.
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  • 18
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Hydrostatic pressure ; Tetraploidy ; Homozygous diploid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hydrostatic pressure and a dye plate method were used to investigate the direct induction of tetraploids or homozygous diploids from the industrial diploid or haploid yeast Saccharomyces cerevisiae. Above 200 MPa, hydrostatic pressure greatly inactivated the strains HF399s1 (α haploid), P-540 (a/α diploid), and P-544 (a/α diploid). At the same time, when pressure-treated cells of these strains were spread on a dye plate, some of the visible colonies were stained red/blue or dark blue (variant colonies); the rest stained violet, similar to colonies originating from diploid cells or haploid cells that were not pressure-treated. In addition, above 100 MPa, the formation of variant colonies increased with increasing pressure, and maximized (1x10-1) at 200 and 250 MPa, respectively. The size of almost all variant cells from P-544, P-540, and HF399s1 was visibly increased compared with that of untreated cells and the measured cellular DNA content of P-540 and HF399s1 was double that of untreated cells. Furthermore, based on random spore analysis and mass-matings, induced variants in the diploid strains were found to be tetraploid with an a/a/α/α genotype at the mating-type locus or, in the haploid strains, homozygous diploid with an α/α genotype. From these results we conclude that pressure treatment in combination with a dye plate is a useful method for strain improvement by direct induction of tetraploids or homozygous diploids from industrial strains whether diploid or haploids.
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  • 19
    ISSN: 1432-0983
    Keywords: Sulphite-resistant mutants ; Sulphite uptake ; Acetaldehyde accumulation ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth inhibition and cell killing caused by sulphite were reduced in seven Saccharomyces cerevisiae sulphite-resistant independent mutants, compared to their parental strains. Genetic analysis showed that in the seven mutants resistance was inherited as a single-gene dominant mutation and that all the analyzed mutations were allelic, thus identifying a major gene responsible for sulphite resistance in S. cerevisiae. Two of the mutants, MBS20-9 and MBS30, were further characterized. 35S-sulphite uptake experiments showed that the ability to accumulate sulphite was markedly reduced in the two resistant strains. No difference between resistant and sensitive strains with respect to glyceraldehyde-3-phosphate dehydrogenase sensitivity to sulphite, or to intracellular glutathione content, were revealed. In contrast, the extracellular acetaldehyde concentration was higher in the resistant mutants, both in the presence and in the absence of sulphite.
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  • 20
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Stationary phase ; mtDNA ; Storage carbohydrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Double-mutant cells of the budding yeast Saccharomyces cerevisiae harboring the gcs1-1 and sed1-1 mutations are conditionally defective (cold-sensitive) only for reentry into the mitotic cycle from stationary phase. If already proliferating at the permissive temperature (29°C), these reentry-mutant cells continue to proliferate when transferred to the restrictive temperature of 14°C, but under these conditions reentry-mutant cells lose mitochondrial DNA (mtDNA). In addition, upon exhaustion of the nutrient supply at 14°C, these reentry-mutant cells entered stationary phase at a decreased cell concentration and did not accumulate the reserve carbohydrates trehalose and glycogen. Both of these deficiencies were due to the loss of mtDNA, as shown by the responses of wild-type cells also lacking mtDNA. Mitochondrial status did not affect other aspects of the reentry-mutant phenotype. Although mitochondrial activity and the accumulation of carbohydrate reserves are typical features of cells in stationary phase, the reentry-mutant phenotype reveals that neither entry into nor exit from stationary phase need involve mitochondrial function.
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  • 21
    ISSN: 1432-0983
    Keywords: Mismatch correction ; Saccharomyces cerevisiae ; Excision repair ; DNA methylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The efficiency and direction of mismatch correction in the Saccharomyces cerevisiae SUP4-o gene were not altered by an excision-repair defect (rad1). Although excision-repair functions remove methylated adenine from yeast, adenine methylation at a GATC sequence in SUP4-o did not direct the correction of mismatches via excision repair.
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  • 22
    ISSN: 1432-0983
    Keywords: DNA repair ; Incoming DNA ; Saccharomyces cerevisiae ; Ultraviolet light
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Purified double- and single-stranded DNAs of the autonomously replicating vector M13RK9-T were irradiated with ultraviolet light (UV) in vitro and introduced into competent whole cells of Saccharomyces cerevisiae. Incoming double-stranded DNA was more sensitive to UV in excision repair-deficient rad2-1 cells than in proficient repair RAD + cells, while single-stranded DNA exhibited high sensitivity in both host cells. The results indicate that in yeast there is no effective rescue of UV-incoming single-stranded DNA by excision repair or other constitutive dark repair processes.
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  • 23
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mitochondria ; Cytochrome c oxidase subunit 1 ; RNA processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eighteen nuclear mutants of the yeast Saccharomyces cerevisiae, each disturbed in the biosynthesis of the mitochondrially encoded cytochrome c oxidase subunit 1 (cox 1) and each representing a distinct complementation group, have been examined to identify the level at which COX1 expression is affected. RNA blotting revealed that most have a defect in the processing of COX1 precursor-mRNA; only a few are defective in COX1 transcription and/or pre-mRNA stability. In most RNA-processing mutants, the absence of the COX1 messenger results from a defect in the splicing of one or more COX1 introns. In turn, this defect can be ascribed to a mutation in a nuclear gene which is either directly involved in splicing or else acts indirectly by impairing COX1 translation.
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  • 24
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Cysteine biosynthetic ; CYS4 ; Mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A DNA fragment containing the CYS4 gene of Saccharomyces cerevisiae was isolated from a genomic library. The cloned fragment hybridized to the transverse-alternating-field-electrophoresis band corresponding to chromosomes VII and XV. According to the 2 μm DNA chromosome-loss procedure, the cys2 and cys4 mutations, which are linked together and co-operatively confer cysteine dependence, were assigned to chromosome VII. By further mapping involving tetrad analysis, the cys2-cys4 pair was localized between SUP77 (SUP166) and ade3 on the right arm of chromosome VII.
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  • 25
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    Current genetics 21 (1992), S. 295-300 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Serine biosynthesis ; Mutant isolation ; Glucose repression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Serine and glycine biosynthesis in yeast proceed by two pathways; a “glycolytic” pathway, using 3-phosphoglycerate, and a “gluconeogenic” pathway, using glyoxylate. We used a mutation in the cat1 gene to abolish the glucose-repressible “gluconeogenic” pathway and re-isolated two mutants, ser1 and ser2, in the “glycolytic” pathway. The ser1 mutation corresponded to phosphoserine transaminase and ser2 to that of phosphoserine phosphatase. Mutagenesis of a ser1 ser2 cat1 triple mutant facilitated the isolation of a mutation in a new gene, SER10. SER10 appears to be part of a pathway which, under normal growth conditions, is less important in serine biosynthesis. The ser1 ser2 ser10 triple mutants were totally serine auxotrophic on glucose media but serine prototrophic during growth on non-fermentable carbon sources. This phenotype was used to select for possible regulatory mutants that synthesize serine by the gluconeogenic pathway even in the presence of glucose, e.g., with a non-glucose repressible glyoxylate cycle. In an alternative approach to isolate such mutants URA3 and TRP1 expression were placed under the control of the glucose-repressible FBP1 (fructose-1,6-bisphosphatase) promoter. Although both systems resulted in strong selection pressure we could not isolate constitutively derepressed mutants. These results indicate that transcription of glucose-repressible gluconeogenic enzymes is mainly dependent on positive regulatory elements.
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  • 26
    ISSN: 1432-0983
    Keywords: Yeast ; Saccharomyces cerevisiae ; Lysis mutants ; Plasmid stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The autonomously replicating plasmid YEpSS1, containing the S. cerevisiae SOD1 and SRB1 genes, was highly unstable in a wild-type strain. When transformed into a fragile srb1-1 mutant host, the same plasmid displayed different characteristics depending on the growth medium used. Both batch and continuous culture experiments demonstrated that the plasmid was very unstable when the transformed strain SLU15 was grown in the presence of an osmotic stabiliser (10% w/v sorbitol). However, in the absence of the osmoticum, nearly 100% of the cells retained the plasmid and produced the Sod1 protein after 80 generations of growth.
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  • 27
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Wine yeasts ; Chromosome length polymorphism ; TAFE ; Probe hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Wine yeast strains are characterized by a high chromosomal DNA polymorphism. This can be explained partly by a size difference of different variants of specific chromosomes. This difference can reach up to 45% of the size of the chromosome in question. Two strains, SB1 and Eg8, have a very complex chromosomal pattern and show one band hybridizing with probes from two different chromosomes derived from a reference strain. This is an indication of the presence of “hybrid” chromosomes in these wine strains. The most astonishing result concerns chromosome VIII, frequently present in wine strains in two variant forms. The first normal form has a size of about 580 kb while the second is around 1000 kb. These two forms segregate at meiosis and recombine with a normal chromosome VIII from a laboratory strain. Wine yeasts are thus very different from haploid laboratory strains.
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  • 28
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    Current genetics 22 (1992), S. 9-11 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; IMP dehydrogenase ; 6-azauracil ; GTP level
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The addition of 6-azauracil to the growth medium causes a strong reduction of the GTP level in the nucleotide pool of Saccharomyces cerevisiae. In-vitro experiments show a strong inhibition of IMP dehydrogenase activity by 6-azaUMP explaining the preceeding effect. PPR2 mutants, previously characterized by an increased sensitivity to 6-azauracil compared to the wildtype, are specifically susceptible to the lowering of the GTP pool, and are able to grow in presence of 6-azauracil when guanine is added to the medium.
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  • 29
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    Current genetics 22 (1992), S. 267-272 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Sterol 14-reductase ; Ergosterol ; Fenpropidin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have transformed Saccharomyces cerevisiae with a genomic library contained in the replicative vector pFL44. The resulting transformants were screened for resistance to fenpropidin, a specific inhibitor of sterol 14-reductase. A plasmid was isolated that transformed yeast both to resistance to fenpropidin and to an increased specific activity of sterol 14-reductase. Sterol analysis of transformed cells grown in the presence of increasing concentrations of the inhibitor confirmed that resistance was a consequence of over-production of sterol 14-reductase. By chromosomal gene disruption, we have, for the first time, constructed yeast strains defective in sterol 14-reductase. As expected, since yeast in unable to take up sterols in aerobiosis, the disrupted strains do not grow in the presence of oxygen, even if exogenous sterols are supplied. However, disrupted cells grow in anaerobiosis with exogenous oleic acid and ergosterol supplemens. They also grow in aerobiosis if they bear an additional mutation allowing sterol uptake. In this last growth condition the cells require a “sparking” ergosterol supplementation (25nM) and accumulate ignosterol (ergosta-8, 14-dienol) as the end-product of the sterol pathway. These results reveal that ignosterol is not obviously toxic to yeast membranes and strongly suggest that the molecular basis of the antifungal-activity morpholine and piperidine is directly related to the specific inhibition of ergosterol formation.
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  • 30
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Fructose-1,6-bisphosphatase ; Glucose repression ; Gene activation ; Gluconeogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fructose-1,6-bisphosphatase is a key enzyme in gluconeogenesis and the FBP1 gene is not transcribed during growth with glucose. Genetic analysis indicated a positive regulation of FBP1 expression after exhaustion of glucose. By linker-deletion analysis, two upstream activation sites (UAS1 and UAS2) were localized and the respective UAS-binding factors (DAP I and DAP II for derepression activating protein) were identified by gel retardation. UAS1 and UAS2 span about 30 bp each, and are separated by approximately 30 bp. Both UAS sites act synergistically. Although UAS1 showed some similarities to the DNA-binding consensus for the general yeast activator Rap1, competition experiments and DEAE-chromatography proved that DAP I and Rap1 correspond to different proteins. Gel retardation by DAP I depended on carbon sources and did not occur in cells growing logarithmically with glucose, whereas a strong retardation signal was obtained with ethanol-grown cells. The present results suggest that DAP I and DAP II are the final regulatory elements for glucose derepression.
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  • 31
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    Archives of microbiology 158 (1992), S. 115-126 
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Yeast cells ; Yeast protoplasts ; Cell wall ; Congo red ; (1 » 3)-β-d-glucan microfibrils ; Cytokinesis ; Reversion of walled protoplasts to cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Congo red was applied to growing yeast cells and regenerating protoplasts in order to study its effects on wall biogenesis and cell morphogenesis. In the presence of the dye, the whole yeast cells grew and divided to form chains of connected cells showing aberrant wall structures on both sides of the septum. The wall-less protoplasts in solid medium with the dye exhibited an abnormal increase in volume, regeneration of aberrant cell walls and inability to carry out cytokinesis or protoplast reversion to cells. In liquid medium, the protoplasts synthesized glucan nets composed mainly of thin fibrils orientated at random, whereas normally, in the absence of dye, the nets consist of rather thick fibrils, 10 to 20 nm in width, assembled into broad ribbons. These fibrils are known to consist of triple 6/1 helical strands of (1 » 3)-β-d-glucan aggregated laterally in crystalline packing. The thin fibrils (c. 4 to 8 nm wide) can contain only a few triple helical strands (c. 1.6 nm wide) and are supposed to be prevented from further aggregation and crystallization by complexing with Congo red on their surfaces. Some loose triple 6/1 helical strands (native elementary fibrils) are also discernible. They represent the first native (1 » 3)-β-d-glucan elementary fibrils depicted by electron microscopy. The effects of Congo red on growth and the wall structure in normal cells and regenerating protoplasts in solid medium can be explained by the presence of a complex which the dye forms with (helical) chain parts of the glucan network and which results in a loss of rigidity by a blocked lateral interaction between the helices.
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  • 32
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    Archives of microbiology 157 (1992), S. 218-222 
    ISSN: 1432-072X
    Keywords: Denitrification ; N2O reductase ; Nitrite reductase ; Immunocytochemistry ; Localization ; Two-dimensional electrophoresis ; Cell fractionation ; Pseudomonas stutzeri
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Immunogold labelling techniques on ultrathin sections of low temperature embedded cells yielded evidence for the periplasmic location of the respiratory enzymes N2O reductase and nitrite reductase (cytochrome cd 1) in Pseudomonas stutzeri strain ZoBell. Cell fractionation by spheroplast preparation and two-dimensional electrophoresis showed the absence of a membrane association of these enzymes. Immunocytochemical localization of N2O reductase in a mutant strain deficient in the chromophore of N2O reductase showed the gold label at the cell periphery, indicating that the copper chromophore processing takes place after export of this protein's apoform.
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  • 33
    ISSN: 1432-072X
    Keywords: Phytochelatin ; Metallothionein ; Heavy metal detoxification ; Saccharomyces cerevisiae ; Neurospora crassa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In fungi, cellular resistance to heavy metal cytotoxicity is mediated either by binding of metal ions to proteins of the metallothionein type or by chelation to phytochelatin-peptides of the general formula (γ-Glu-Cys)n-Gly. Hitherto, only one fungus, Candida glabrata has been shown to contain both metal inactivating systems. Here we show by unambiguous FAB-MS analysis that both a metallothionein-free mutant of Saccharomyces cerevisiae as well as a wildtype strain synthesize phytochelatin (PC2) upon exposure to 250 μM Cd2+ ions. The presence of Zn and/or Cu ions in the nutrient broth also induces PC2 synthesis in this organism. By 109Cd exchange and subsequent monobromobimane fluorescence HPLC, it could be shown that the presence of Cd2+ in the growth medium also induces phytochelatin synthesis in Neurospora crassa, which contains metallothioneins.
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  • 34
    ISSN: 1573-5028
    Keywords: Brassica napus ; chloroplast ; 3-isopropylmalate dehydrogenase ; molecular evolution ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Both insect and mammalian genes have previously been cloned by genetic complementation in yeast. In the present report, we show that the method can be applied also to plants. Thus, we have cloned a rape cDNA for 3-isopropylmalate dehydrogenase (IMDH) by complementation of a yeast leu2 mutation. The cDNA encodes a 52 kDA protein which has a putative chloroplast transit peptide. The in vitro made protein is imported into chloroplasts, concomitantly with a proteolytic cleavage. We conclude that the rape cDNA encodes a chloroplast IMDH. However, Southern analysis revealed that the corresponding gene is nuclear. In a comparison of IMDH sequences from various species, we found that the rape IMDH is more similar to bacterial than to eukaryotic proteins. This suggests that the rape gene could be of chloroplast origin, but has moved to the nucleus during evolution.
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  • 35
    ISSN: 1432-1890
    Keywords: Ericaceae ; Mycorrhizal fungi ; Acid phosphatase ; Protein expression ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The activity of acid phosphatase produced in pure culture by the endomycorrhizal fungus Hymenoscyphus ericae (Read) Korf & Kernan (H. ericae LPA 2) was inhibited by high phosphorus levels, alkaline pH, fluoride, molybdate and mannosidase, and activated by concanavalin A. Over 80% of the enzyme activity was due to two wall-bound acid phosphatase isozymes with the characteristics of mannose-rich glycoproteins. Antiserum was raised against the major, low-molecular-weight wall isozyme and its activity tested by immunoblotting and ELISA. The antiserum cross reacted 100% with exocellular (excreted) and 28% with cytoplasmic cellular fractions of H. ericae (LPA 2) cultures, and showed high reactivity with other strains of H. ericae but not with fungal isolates from Erica hispidula L. or E. mauritanica L. Ultrastructural localization of acid phosphatase by cytoenzymology and indirect immunogold labelling confirmed its association with the fungal wall in pure culture and showed that the influence of a high phosphorus level, fluoride and molybdate is through inactivation of the enzyme. Intense acid phosphatase activity, sensitive to the latter inhibitors, was also present on external hyphae growing over a host or non-host root but it was weak or absent from intracellular hyphae where these developed within a host root. Indirect immunolabelling confirmed that this acid phosphatase was of fungal origin and that the specific inhibitory effect of host cells is due to inactivation of the enzyme rather than repression of its synthesis. Possible implications of fungal acid phosphatase in ericoid endomycorrhizal infection processes are discussed together with mechanisms that may be regulating the enzyme activity.
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  • 36
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    Cell & tissue research 270 (1992), S. 395-404 
    ISSN: 1432-0878
    Keywords: Nucleus sacci vasculosi ; Ultrastructure ; Immunocytochemistry ; Hypothalamus ; Tuberculum posterius ; Scyliorhinus caniculus, Raja undulata (Elasmobranchii)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The elasmobranch nucleus sacci vasculosi was studied by means of electron microscopy (in the dogfish) and immunocytochemistry (in the dogfish and the skate) by using antibodies against tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P. Ultrastructural study of the dogfish nucleus sacci vasculosi shows the presence of medium-sized cells that possess numerous mitochondria but that have no dense-core vesicles in the cytoplasm or in cell processes. Fibres of the conspicuous tractus sacci vasculosi have a beaded appearance and form conventional synapses with dendrites and cell perikarya of the nucleus sacci vasculosi. The perikarya of this hypothalamic nucleus were not immunoreactive to any of the antibodies tested, and fibres immunopositive to tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P were scarce within this nucleus, in both the dogfish and the skate. Dorsal to the nucleus sacci vasculosi, there are numerous positive neuronal processes in addition to many small neurons that show immunoreactivity to alpha-melanocyte-stimulating hormone, somatostatin and tyrosine hydroxylase. Two types of neuron occur in this dorsal region, displaying dense-core vesicles of either 100–160 nm or 60–100 nm diameter in their cytoplasm; they were identified as peptide-containing and monoamine-containing neurons, respectively. The neuropil of this region has a significantly different ultrastructure from that of the nucleus sacci vasculosi, with many processes containing dense-core vesicles. This group of neurons, located dorsal to the nucleus sacci vasculosi and showing (a) immunoreactivity to neuropeptides or to monoamine-synthesizing enzyme, and (b) cytoplasm with dense-core vesicles, was considered not to be a part of the nucleus sacci vasculosi but rather part of the nucleus tuberculi posterioris. These results support the non-peptidergic and non-aminergic character of the nucleus sacci vasculosi.
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  • 37
    ISSN: 1432-0878
    Keywords: Serotonin ; Whole-mount ; Immunocytochemistry ; Insect ventral nervous system ; Interneurons ; Efferent neurons ; Leptinotarsa decemlineata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an immunohistochemical study of the ventral nerve cord of L. decemlineata, five distinct neuron categories were distinguished: 1) Two paired segmental twin interneurons occur in each ganglion or neuromere; their axons distribute processes over almost the entire nerve cord and run to the cerebral ganglion complex. In contrast, other axons are distributed locally. 2) Four large frontal neurosecretory neurons occur in the suboesophageal ganglion (SOG), two of which have axons that run into the mandibular nerves to form a neurohemal plexus on the surface of cerebral nerves. 3) A pair of large caudal neurons occur in the terminal ganglion and innervate the hindgut. 4) Local miniature interneurons occur in the SOG. 5) Terminal neurons are present in the last abdominal ganglion. Segmental twin interneurons appear to be grouped into 3 ‘functional units’ spanning several ganglia. Their axons run to specific projection areas, which separate the functional units, and which mark the externally visible separation of condensed ganglion complexes. A possible role of the most caudal functional unit might be the synaptic control of caudal neurons innervating the hindgut.
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  • 38
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    Cell & tissue research 270 (1992), S. 469-474 
    ISSN: 1432-0878
    Keywords: Pericytes ; Angiogenesis ; Capillaries ; Capillary sprouting ; Desmin ; Immunocytochemistry ; Rat Adenocarcinoma cells, rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To investigate the participation of microvascular pericytes in the process of capillary sprouting, we examined whole-mount preparations of the rat mesentery by use of a double immunofluorescence approach. Angiogenesis was induced by intraperitoneal injections of either the mast cell-degranulating substance compound 48/80 or tumor cell-conditioned medium. Capillary sprouts were visualized by staining with rhodaminconjugated phalloidin and pericytes were simultaneosly stained by an antibody to the intermediate filament protein desmin. Developing pericytes were negative for the smooth-muscle isoform of α-actin, bbut were clearly reactive for desmin. Pericytes appear to be involved in the carliest stages of capillary sprouting. Pericytes were regularly found lying at and in front of the advancing tips of endothelial sprouts. At many sites pericytes were seen to bridge the gap between the leading edges of opposing endothelial sprouts, which were apparently preparing to merge, suggesting that pericytic processes may serve as guiding structures aiding outgrowth of endothelial cells.
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  • 39
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    Cell & tissue research 267 (1992), S. 125-130 
    ISSN: 1432-0878
    Keywords: Sensory ganglia ; Sympathetic ganglia ; Parasympathetic ganglia ; Basic fibroblast growth factor ; Substance P ; Somatostatin ; Bombesin ; Immunocytochemistry ; Rat (Wistar: Han)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of basic fibroblast growth factor (bFGF)-immunoreactivity (IR) was studied in rat sensory and autonomic ganglia. In postnatal and adult sympathetic superior cervical ganglia and in adult parasympathetic otic ganglia no bFGF-staining was found. Postnatal and adult neural crest-and placode-derived sensory ganglia displayed intensive bFGF-IR in a neuronal subpopulation. This subpopulation was characterized by use of consecutive sections of adult dorsal root ganglia stained with antibodies against substance P, somatostatin, bombesin, and bFGF. Basic FGF was colocalized with the somatostatin/bombesin subpopulation but not with substance P.
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  • 40
    ISSN: 1432-0878
    Keywords: Dopamine ; Tyrosine hydroxylase ; Histamine ; Immunocytochemistry ; Insect nervous system ; Drosophila melanogaster, Phormia terraenovae, Calliphora erythrocephala (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution and morphology of neurons reacting with antisera against dopamine (DA), tyrosine hydroxylase (TH) and histamine (HA) were analyzed in the blowflies Calliphora erythrocephala and Phormia terraenovae. TH-immunoreactive (THIR) and HA-immunoreactive (HAIR) neurons were also mapped in the fruitfly Drosophila melanogaster. The antisera against DA and TH specifically labeled the same neurons in the blowflies. About 300 neurons displayed DA immunoreactivity (DAIR) and THIR in the brain and subesophageal ganglion of the blowflies. Most of these neurons were located in bilateral clusters; some were distributed as bilateral pairs, and two ventral unpaired median (VUM) neurons were seen in the subesophageal ganglion. Immunoreactive processes were found in all compartments of the mushroom bodies except the calyces, in all divisions of the central body complex, in the medulla, lobula and lobula plate of the optic lobe, and in non-glomerular neuropil of protocerebrum, tritocerebrum and the subesophageal ganglion. No DA or TH immunoreactivity was seen in the antennal lobes. In Drosophila, neurons homologous to the blowfly neurons were detected with the TH antiserum. In Phormia and Drosophila, 18 HA-immunoreactive neurons were located in the protocerebrum and 2 in the subesophageal ganglion. The HAIR neurons arborized extensively, but except for processes in the lobula, all HAIR processes were seen in non-glomerular neuropil. The deuto- and tritocerebrum was devoid of HAIR processes. Double labeling experiments demonstrated that TH and HA immunoreactivity was not colocalized in any neuron. In some regions there wasm however, substantial superposition between the two systems. The morphology of the extensively arborizing aminergic neurons described suggests that they have modulatory functions in the brain and subesophageal ganglion.
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  • 41
    ISSN: 1432-0878
    Keywords: Fetal intermediate lobe ; Tissue culture ; Immunocytochemistry ; In situ hybridization ; Dopamine ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Organotypic cultures, in defined medium, of pituitary primordia obtained from 15-day-old rat fetuses were performed in order to study the in vitro differentiation of melanotrophic cells. The morphological and ultrastructural features of the transplants resembled those of the gland developing in vivo. In situ hybridization on semi-thin sections, using a 35S-labelled oligonucleotide probe, revealed pro-opiomelanocortin-mRNA-containing cells on the first day of culture in the anterior lobe and after 2–3 days in the intermediate lobe. Immunoperoxidase labelling of adjacent sections showed that the same cells reacted with antibodies against α-melanocyte-stimulating hormone (αMSH), γ3 and adrenocorticotropic hormone in both lobes. The pro-opiomelanocortin-mRNA-containing cells formed progressively conspicuous areas in the intermediate lobe, which was almost uniformly labelled after 6 days. In the anterior lobe, these cells remained scattered in small cell groups, and colloidal gold immunolabelling showed the progressive disappearance of αMSH labelling from the secretory vesicles in cells exhibiting morphological features of adult corticotrophic cells. Both the αMSH content of the explants and αMSH release into the culture medium increased with time. Treatment with the dopamine agonist bromocriptine induced a strong dose-dependent decrease in αMSH secretion, which was significant after 3 days in culture, indicating that dopamine D2 receptors are able to regulate hormonal release of melanotrophic cells at early stages. This system constitutes a suitable model for further studies of factors controlling cell differentiation and cellular interactions involved in histogenesis.
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  • 42
    ISSN: 1432-0878
    Keywords: Cerebral ganglia ; Neurohormones ; Molluscan insulin-related peptide ; Immunocytochemistry ; Tannic acid ; Planorbarius corneus (Mollusca)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two groups of cerebral dorsal cells of the pulmonate snail Planorbarius corneus stain positively with antisera raised against synthetic fragments of the B- and C-chain of the molluscan pro-insulin-related prohormone, proMIP-I, of another pulmonate snail, Lymnaea stagnalis. At the light-microscopic level the somata of the dorsal cells and their axons and neurohemal axon terminals in the periphery of the paired median lip nerves are immunoreactive with both antisera. Furthermore, the canopy cells in the lateral lobes of the cerebral ganglia are positive. In addition, MIPB-immunoreactive neurons are found in most other ganglia of the central nervous system. At the ultrastructural level, pale and dark secretory granules are found in somata and axon terminals of the dorsal cells. Dark granules are about 4 times as immunoreactive to both antisera as pale granules. Release of anti-MIPB- and anti-MIPC-immunopositive contents of the secretory granules by exocytosis is apparent in material treated according to the tannic acid method. It is concluded that the dorsal and canopy cells synthesize a molluscan insulin-related peptide that is packed in the cell body into secretory granules and that is subsequently transported to the neurohemal axon terminals and released into the hemolymph by exocytosis. Thus, MIP seems to act as a neurohormone on peripheral targets. On the basis of the analogy between the dorsal cells and the MIP-producing cells in L. stagnalis, it is proposed that the dorsal cells of P. corneus are involved in the control of body growth and associated processes.
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  • 43
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    Cell & tissue research 267 (1992), S. 483-492 
    ISSN: 1432-0878
    Keywords: Dental follicle ; Cell culture ; Fibroblasts ; Immunocytochemistry ; Ultrastructure ; Collagen ; Gel-electrophoresis ; Western blotting ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Because the dental follicle is necessary for the eruption of teeth of limited eruption, it was the objective of this study to determine if the cells of the follicle could be cultured in vitro. To achieve this, dental follicles and associated enamel organs were dissected from the first and second mandibular molars of 6–7-day-old rats (secretory stage of amelogenesis), and then cultured in a medium that promotes fibroblast growth — the predominant cell type of the dental follicle. The cultured cells grew to confluency and were kept through 3 passages before experimentation. The cultured cells were fibroblastic in shape, elongate with processes, and transmission electron microscopy revealed that they contained an abundant rough endoplasmic reticulum, but did not form desmosomes. Immunofluorescent staining for anti-vimentin showed that all the cells stained and electron-microscopic immunogold labeling indicated that the antibody was associated with intermediate filaments. As revealed by SDS-polyacrylamide gel electrophoresis and Western blotting, the cultured cells synthesized and secreted the extracellular matrix molecules fibronectin and procollagens. Subsequent immunofluorescence staining of permeabilized and non-permeabilized cells confirmed the presence of fibronectin and type I collagen both intra- and extracellularly. Thus, based on all the above characteristics, the cultured cells appeared to be fibroblasts derived from the dental follicle, although a few of the fibroblasts may be derived from undifferentiated mesenchymal cells interposed between the alveolar bone and follicle. Experiments now can be conducted to determine how these cultured cells respond directly to growth factors that alter the rates of tooth eruption.
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  • 44
    ISSN: 1432-0878
    Keywords: Actin-like protein ; Fibronectin-like protein ; Regeneration ; Cell migration ; Immunocytochemistry ; Dugesia lugubris (Tricladida)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Actin- and fibronectin-like proteins were characterized in the planarian, Dugesia lugubris s.l., by sodium dodecyl sulphate polyacrylamide gel electrophoresis and immunoblotting analysis using antisera to vertebrate actin and fibronectin. These antisera recognized protein bands of 42 kDa and 220 kDa, respectively. In addition, the immunohistochemical distribution of both actin- and fibronectin-like material was examined by using immuno-electron microscopy. Actin-like protein was localized in myofibrils in various differentiation stages, and in the peripheral cytoplasm and lamellipodia of cells that were migrating. The fibronectin-like component was associated with the extracellular matrix in the fibrillar structures and with the surface of the migrating cells. Our data suggest that similar cellular and molecular mechanisms are involved in cell-matrix interactions and in the morphogenesis of living organisms at different evolutionary levels.
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  • 45
    ISSN: 1432-0878
    Keywords: Retina ; Dopaminergic neurons ; Synapses ; Inner plexiform layer ; Immunocytochemistry ; Electron microscopy ; Bufo marinus (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tyrosine hydroxylase (TH) immunocytochemistry was utilized to quantify dopaminergic synapses in the inner plexiform layer of the retina of Bufo marinus. Since dopaminergic cells have bistratified dendritic arborisation in the inner plexiform layer, attention was given to the segregation of synapses between the scleral and the vitreal sublaminae. Light-microscopically, a more elaborate dendritic branching was observed in the scleral than in the vitreal sublamina. In contrast, about 55% of synapses occurred in the vitreal one fifth of the inner plexiform layer, 30% in the scleral fifth, and 15% in the intermediate laminae. Input sources and output targets showed only minor quantitative differences between sublaminae 1 and 5. TH-immunoreactive processes were found in presynaptic (62.8%) and postsynaptic (37.2%) positions. Synapses to the stained dendrites derived from bipolar (40.4%) and amacrine (59.6%) cells, whereas outputs from the TH-positive processes were directed to amacrine cells (56.8%) and to small and medium-sized dendrites (35.4%); at least some of these can be considered as ganglion cell dendrites. TH-positive profiles neither formed synapses with each other nor were presynaptic to bipolar cell terminals. Junctional appositions of the immunoreactive profiles were occasionally seen on non-stained amacrine and ganglion cell dendrites in the scleral sublamina of the inner plexiform layer and on optic axons in the optic fibre layer. Although dopaminergic cells are mainly involved in amacrine-amacrine interactions, inputs from bipolar terminals and outputs to ganglion cell dendrites were also substantial, suggestive of a role also in vertical information processing.
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  • 46
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    Cell & tissue research 268 (1992), S. 65-70 
    ISSN: 1432-0878
    Keywords: Stanniocalcin ; Corpuscles of Stannius ; Embryology ; Immunocytochemistry ; Pronephros ; Oncorhynchus keta (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An immunocytochemical technique was used to follow the embryological origin and development of the corpuscles of Stannius (CS) in the chum salmon, Oncorhynchus keta. Stanniocalcin immunoreactive (ir-) cells can be observed as early as 13 days before hatching. The ir-CS cells appear in clusters of variable size in close association with nephric ducts. In addition, individual ir-cells also occur at this stage amoung epithelial cells of the nephric ducts. these individual cells may give rise to clusters which subsequently increase in size, the largest reaching 100 μm in diameter by the time of hatching. During this period, dispersed CS cells become evident and develop into secondary clusters in the vicinity of the primary clusters. These clusters appear to fuse to form larger clusters with a lobular structure. Transfer of the larvae (20 days after hatching) from fresh water to 50% seawater, accelerates the development of the CS tissue, suggesting an important role of the CS in seawater adaptation.
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  • 47
    ISSN: 1432-0878
    Keywords: Neuropeptide Y ; Brain, vertebrate ; Hypothalamus ; Pituitary gland, pars intermedia ; Nervus terminalis ; Immunocytochemistry ; Scyliorhinus torazame (Elasmobranchii)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using a specific antiserum raised against synthetic neuropeptide Y, we examined the localization of immunoreactivity in the brain and hypophysis of the cloudy dogfish, Scyliorhinus torazame, by the peroxidase-antiperoxidase method. Immunoreactive perikarya were demonstrated in the ganglion of the nervus terminalis, the dorsocaudal portions of the pallium dorsale, the basal telencephalon, and the nucleus lateralis tuberis and the nucleus lobi lateralis in the hypothalamus. Labeled perikarya were also found in the tegmentum mesencephali, the corpus cerebelli, and the medulla oblongata. Some of the immunoreactive neurons in the hypothalamus were of the CSF-contacting type. The bulk of the labeled fibers in the nervus terminalis ran toward the basal telencephalon, showing radial projections and ramifications. Large numbers of these fibers coursed into the nucleus septi caudoventralis and the nucleus interstitialis commissurae anterioris, where they became varicose and occasionally formed fine networks or invested immunonegative perikarya. In the diencephalon, immunoreactive fibers were observed throughout the hypothalamus, e.g., in the pars neurointermedia of the hypophysis, the subependymal layer of the lobus inferior hypothalami, and in the neuropil of the posterior (mammillary) recess organ. Labeled fibers were scattered throughout the rest of the brain stem and were also seen in the granular layer of the cerebellum. These results suggest that, in the dogfish brain, neuropeptide Y or a related substance is involved in a variety of physiological processes in the brain, including the neuroendocrine control of the hypophysis.
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  • 48
    ISSN: 1432-0878
    Keywords: Olfactory epithelium ; Comparative study ; Histochemistry ; Immunocytochemistry ; Non-specific label ; Microsmatic fish ; Three-spined stickleback, Gasterosteus aculeatus (Teleostei) ; Nine-spined stickleback, Pungitius pungitius (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The olfactory epithelium of the three-spined stickleback (Gasterosteus aculeatus) and the nine-spined stickleback (Pungitius pungitius) has been studied with a conventional histochemical and a novel immunological staining technique. In both species, the sensory epithelium is arranged in folds separated by non-sensory epithelial tissue. In the nine-spined stickleback, intrinsic folds consisting of non-sensory cells are found in the apical part of the sensory epithelium where they divide the surface of the sensory epithelium into small islets. These non-sensory cells are non-ciliated, flattened and piled on top of each other; they contain numerous electron-translucent vesicles. The intrinsic folds are absent from the sensory epithelium of the three-spined stickleback. In both species, axons of receptor cells form a layer of fibers in the sensory epithelium immediately above the basal cells. In the three-spined stickleback, thick branches of the olfactory nerve are frequently found in this layer. These branches are only occasionally observed in the sensory epithelium of the nine-spined stickleback. Thus, the three-spined stickleback and the nine-spined stickleback show considerable differences in the organization of the sensory regions of the olfactory epithelium.
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  • 49
    ISSN: 1432-0878
    Keywords: Pituitary adenylate cyclase-activating peptide (PACAP) ; Immunocytochemistry ; Pancreas, endocrine, exocrine ; Insulin secretion ; Glucagon secretion ; Mouse (NMRI) ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide that occurs in several tissues, e.g., in the gut. We have studied PACAP-like immunoreactivity in the pancreas of rat and mouse, and the effects of PACAP-38 on basal and stimulated insulin and glucagon secretion in the mouse. Immunofluorescence staining demonstrated the presence of PACAP-like immunoreactivity in nerve fibers in both the rat and mouse pancreas. The nerve fibers were seen in the exocrine pancreas and surrounding the islets. Occasionally, the nerve fibers occurred within the islets. Most PACAP-positive nerve fibers innervated the intrapancreatic ganglia, although no nerve cell bodies contained PACAP-like immunoreactivity. In-vivo experiments in mice revealed that basal plasma glucagon levels were increased by PACAP-39 injected intravenously at dose levels exceeding 1.8 nmol/kg. Furthermore, PACAP-38 (7 nmol/kg) potentiated the plasma glucagon response to the cholinergic agonist carbachol (0.16 μmol/kg). This potentiation was reduced to simple addition by pretreatment with a combined α- and β-adrenergic blockade by phentolamine (35 μmol/kg) and propranolol (8.5 μmol/kg). Moreover, PACAP-38 inhibited a carbachol-induced increase in the level of plasma insulin in the absence but not in the presence of adrenergic blockade. PACAP-38 increased basal plasma insulin levels and increased basal plasma glucose levels 6 min and 10 min, respectively, after injection of the peptide. We conclude that PACAP-like immunoreactivity exists in nerve fibers innervating the mouse and rat pancreas, particularly the intrapancreatic ganglia, and that PACAP-38 augments both basal and carbachol-stimulated glucagon secretion in the mouse.
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  • 50
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    Cell & tissue research 269 (1992), S. 315-322 
    ISSN: 1432-0878
    Keywords: Calcitonin gene-related peptide ; Islet amyloid polypeptide ; Immunocytochemistry ; Pancreas endocrine, exocrine ; Rat (Sprague-Dawley) ; Mouse (NMRI)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It was previously demonstrated that the two chemically related peptides calcitonin gene-related peptide (CGRP) and islet amyloid polypeptide (IAPP) both occur in the pancreas. We have now examined the cellular localization of CGRP and IAPP in the rat and the mouse pancreas. We found, in both the rat and the mouse pancreas, CGRP-immunoreactive nerve fibers throughout the parenchyma, including the islets, with particular association with blood vessels. CGRP-immunoreactive nerve fibers were regularly seen within the islets. In contrast, no IAPP-immunoreactive nerve fibers were demonstrated in this location. Furthermore, in rat islets, CGRP immunoreactivity was demonstrated in peripherally located cells, constituting a major subpopulation of the somatostatin cells. Such cells were lacking in the mouse islets. IAPP-like immunoreactivity was demonstrated in rat and mouse islet insulin cells, and, in the rat, also in a few non-insulin cells in the islet periphery. These cells seemed to be identical with somatostatin/CGRP-immunoreactive elements. In summary, the study shows (1) that CGRP, but not IAPP, is a pancreati neuropeptide both in the mouse and the rat; (2) that a subpopulation of rat somatostatin cells contain CGRP; (3) that mouse islet endocrine cells do not contain CGRP; (4) that insulin cells in both the rat and the mouse contain IAPP; and (5) that in the rat, a non-insulin cell population apparently composed of somatostatin cells stores immunoreactive IAPP. We conclude that CGRP is a pancreatic neuropeptide and IAPP is an islet endocrine peptide in both the rat and the mouse, whereas CGRP is an islet endocrine peptide in the rat.
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  • 51
    ISSN: 1432-0878
    Keywords: Growth hormone ; Prolactin ; Gonadotropin ; Adrenocorticotropin ; Immunocytochemistry ; Pituitary gland ; Sparus auratus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The chronological appearance of endocrine cells in the pituitary of sea-bream (Sparus auratus) larvae was studied using antisera against salmon prolactin, trout growth hormone, salmon gonadotropin and N-terminal human adrenocorticotropin. The larval pituitary (1–12 days after hatching) was oval in shape and was composed of a dense mass of cells with few neurohypophysial fibres. By 60 days after hatching it began to resemble the adult and was divisible into a distinct rostral pars distalis containing prolactin and adrenocorticotropin cells; a proximal pars distalis containing somatotrophs and gonadotrophs and a pars intermedia. Cells immunoreactive with antisera against growth hormone were observed immediately after hatching (2 days post-fertilization). Weakly staining prolactin cells were observed 2 days later in the region corresponding to the rostral pars distalis. Cells immunoreactive with anti-gonadotropin and anti-adrenocorticotropin sera were observed in the pituitary 6 and 8 days after hatching, respectively. All the cell-types studied were immunoreactive from the time they were first identified until the final samples 90 days after hatching.
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  • 52
    ISSN: 1432-0878
    Keywords: Dental pulp ; Laminin ; Collagen IV ; Odontoblast ; Nerve regeneration ; Immunocytochemistry ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of laminin-like immunoreactivity in adult normal and denervated cat mandibular tooth pulps was studied by the use of fluorescence microscopy and pre-embedding immunogold electron microscopy. Immunoreactivity to collagen IV was also assessed in order to distinguish basement membranes. In normal pulps, light-microscope laminin-like immunoreactivity was strong along blood vessels and Schwann cell sheaths, and a faint immunoreactivity was seen also in the odontoblast layer. Electron microscopy confirmed the laminin-like immunoreactivity of endothelial and Schwann cell basement membranes at all pulpal levels. In the odontoblast layer and the predentine, nerve-like structures lacking basement membranes but possessing strong membrane laminin-like immunoreactivity were encountered. In addition, a clear-cut laminin-like immunoreactivity of plasma membranes of the somata and processes of odontoblasts was seen. Observations on denervated pulps as well as pulps in which nerve regeneration had taken place did not reveal any changes in the pattern of laminin-immunoreactivity in basement membranes or odontoblasts. Distribution of collagen IV-like immunoreactivity was very similar to laminin-like immunoreactivity in basement membranes of blood vessels and Schwann cells, and appeared unaffected by denervation. The odontoblasts and nerve-like profiles in the odontoblast layer were devoid of collagen IV-like immunoreactivity. We propose that odontoblast-associated laminin could be of significance as guidance for regenerating terminal pulpal nerve fibers to appropriate targets.
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  • 53
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    Cell & tissue research 270 (1992), S. 47-56 
    ISSN: 1432-0878
    Keywords: Cilia ; Microvilli ; Secretory granules ; Mucus ; Freeze-substitution ; Immunocytochemistry ; Rana pipiens (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study showed that the olfactory mucus is a highly structured extracellular matrix. Several olfactory epithelial glycoconjugates in the frog Rana pipiens were localized ultrastructurally using rapid-freeze, freeze-substitution and post-embedding (Lowicryl K11M) immunocytochemistry. Two of these conjugates were obtained from membrane preparations of olfactory cilia, the glycoproteins gp95 and olfactomedin. The other conjugates have a carbohydrate group which in the olfactory bulb appears to be mostly on neural cell-adhesion molecules (N-CAMs); in the olfactory epithelium this carbohydrate is present on more molecules. Localization of the latter conjugates was determined with monoclonal antibodies 9-OE and 5-OE. Ultrastructurally all antigens localized in secretory granules of apical regions of frog olfactory supporting cells and in the mucus overlying the epithelial surface, where they all had different, but partly overlapping, distributions. Monoclonal antibody 18.1, to gp95, labeled the mucus throughout, whereas poly- and monoclonal anti-olfactomedin labeled a deep mucous layer surrounding dendritic endings, proximal parts of cilia, and supporting cell microvilli. Labeling was absent in the superficial mucous layer, which contained the distal parts of the olfactory cilia. Monoclonal antibody 9-OE labeled rather distinct areas of mucus. These areas sometimes surrounded dendritic endings and olfactory cilia. Monoclonal antibody 5-OE labeled membranes of dendritic endings and cilia, and their glycocalyces, and also dendritic membranes.
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  • 54
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    Cell & tissue research 270 (1992), S. 601-607 
    ISSN: 1432-0878
    Keywords: Dopamine ; HPLC ; Immunocytochemistry ; Hydra attenuata (Cnidaria)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary High performance liquid chromatography (HPLC), with electrochemical detection, is an analytical method sensitive enough to permit quantification of dopamine, dihydroxyphenylalanine (DOPA) and 5-S-cysteinyl DOPA in single or hemisected specimens ofHydra attenuata. Dopamine and 5-S-cysteinylDOPA appear to be the quantitatively predominant catechol compounds inH. attenuata, whereas DOPA is present in minor amounts. The presence of DOPA and 5-S-cysteinylDOPA, and the quantitative correlation between dopamine and these compounds in many specimens, suggests that dopamine inH. attenuata, as in higher animals, is formed through decarboxylation of DOPA. Contrary to the dopaminergic nerves in higher animals, DOPA inHydra seems to be oxidized and 5-S-cysteinyl DOPA is formed as a by-product. The oxidation of DOPA indicates that the hydroxylation of tyrosine into DOPA in the tissues ofH. attenuata is mediated by a tyrosinase rather than a tyrosine hydroxylase. Immunocytochemical methods demonstrate a highly variable distribution of dopamine in the tissues of different specimens ofH. attenuata. Dopamine immunoreactivity is confined to ectodermal tissue and can be found in several different cell types including nerve cells, battery cells, nematocytes, epithelial cells and interstitial undifferentiated cells. The large amounts of dopamine found in some specimens ofH. attenuata indicate some biological function, although its sporadic occurrence in neurites makes it less plausible as a generally utilized neurotransmitter in this animal.
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  • 55
    ISSN: 1432-0878
    Keywords: Gastrin ; Gastrin-releasing peptide ; Neurotensin ; Vasoactive intestinal peptide ; Immunocytochemistry ; Harderian gland ; Rana esculenta (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The presence and distribution of gastrin-, gastrin-releasing peptide-, neurotensin-and vasoactive intestinal polypeptide-like immunoreactivity in the Harderian gland ofRana esculenta were studied at different times of the annual cycle. Gastrin-releasing peptide, neurotensin and vasoactive intestinal polypeptide-like substances were found either in the glandular cells, or in the nerve fibers surrounding the glandular acini. Gastrin-like immunoreactivity was confined to the glandular cells. The immunoreactivity varied during the annual cycle, with the greatest concentration being noted during the recovery phase of glandular secretory activity.
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  • 56
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Serotonin ; RFamide ; Development ; Paraspadella gotoi (Chaetognatha)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution and development of serotonin-and RFamide-like immunoreactivities in the nervous system of Chaetognatha, Paraspadella gotoi, were examined in whole-mount preparations. In adults, a single serotonin-like immunoreactive (5HTLI) neuron and numerous RFamide-like immunoreactive (RFaLI) neurons were found in the central nervous system. Based on the structure of the fins, hooks, and eyes, seven postembryonic developmental stages were recognized. The most obvious features of the stages are: stage 1, newly hatched young; stage 2, elongation of a continuous lateral tail fin; stage 3, separation of the lateral and tail fins; stage 4, appearance of hooks; stage 5, pigmentation of eyes, stage 6, attachment by tail adhesive fins; stage 7, prey capture. Stage 1 did not show any immunoreactivity. The 5HTLI neuron first appeared at stage 4 and its axonal pathway became similar to the adult at stage 6. On the other hand, the RFaLI neurons appeared at stage 3 in the ventral ganglion. Some of their somata disappeared at stage 5 and the neuronal architecture resembled the adult at stage 7 although the RFaLI neurons in the cerebral ganglion were complete at the juvenile stage.
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  • 57
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    Cell & tissue research 267 (1992), S. 209-214 
    ISSN: 1432-0878
    Keywords: Testis ; Sulfhydryl oxidase ; Hypospermatogenesis ; Sertoli cell integrity ; Immunocytochemistry ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sulfhydryl oxidase (SOx) immunoreactivity was investigated in the seminiferous epithelium of human biopsy material from the testes of 33 adult men with disturbed fertility. SOx immunoreactivity was expressed in normal seminiferous epithelium in type-A spermatogonia (27±4% of all spermatogonia) (n=4), in spermatocytes and round spermatids. Mature spermatozoa as well as Sertoli cells were unlabelled. within the interstitium, Leydig cells were immunopositive. In biopsies of oligozoospermic men showing hypospermatogenesis (n=24), an increase in labelled spermatogonia up to more than 90% was observed in biopsies, where seminiferous epithelia revealed only spermatogonia and Sertoli cells. Within the group of oligozoospermic patients there was a significant increase of labelled spermatogonia from 43±13% (〉20 mill/ejaculate) (n=7) to 55±16% ( 20 and 〉20 mill/ejaculate) (n=6) to 68±8% (〈5 mill/ejaculate) (n=11) and a significant (P=0.01) decrease of score count from 7.0±2.7 to 2.0±1.8. In this group the increase of labelled spermatogonia was correlated with sperm concentrations in the ajaculate (correlation coefficient: r=-0.6). In biopsies of azoospermic patients showing maturation arrest at the level of spermatocytes or spermatids (n=5) the percentage of labelled spermatogonia was within the range of 24% to 59%. Immunoreactivity in Sertoli cells was only found in single degenerating cells and in tubules showing Sertoli Cell Only Syndrome (SCO) without lumen formation. Sertoli cells within immature seminiferous cords were immunonegative, indicating that Sertoli cell SOx immunoreactivity is rather a sign of physiological alterations in degenerating cells than dependent on the stage of differentiation. Leydig cells did not show changes of immunoreactivity in any biopsy. It is concluded that SOx expression in spermatogonia may serve as a marker for spermatogenic efficiency.
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  • 58
    ISSN: 1432-0878
    Keywords: α-Subunit ; Pituitary glycoprotein hormone ; PRL cell ; Pars distalis ; Colocalization ; Immunocytochemistry ; Bullfrog, Rana catesbeiana (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Our recent finding that the number of immunoreactive α-subunit cells was invariably greater than the total number of immunoreactive gonadotropin (GTH) and thyrotropin (TSH) cells in the bullfrog (Rana catesbeiana) pituitary gland raises the possibility that the α-subunit also exists in pituitary cells other than GTH and TSH cells. The present study demonstrates that there are a considerable number of immunoreactive prolactin (PRL) cells that are also stained with antibody against the α-subunit when adjacent sections are immunocytochemically examined. Neither immunoreactive growth hormone nor adrenocorticotropin cells are stained with the antibody against the α-subunit. The specificity of the antibody against the α-subunit and of that against PRL was demonstrated by preabsorption test, non-competitive binding test, and immunoblot analysis. Double-immunolabeling with gold particles of different sizes for the α-subunit and PRL revealed that most of the immunolabeled PRL-secretory granules are also labeled with the α-subunit antibody. The gold particles indicating the presence of the α-subunit were mostly found in the peripheral zone of the secretory granules.
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  • 59
    ISSN: 1432-0878
    Keywords: Nervous system, central ; VD1/RPD2 system ; Neuropeptide immunocytochemistry ; Hybridization, in situ ; Immunocytochemistry ; Lymnaea stagnalis (Mollusca)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary VD1 and RPD2 are two giant neuropeptidergic neurons in the central nervous system (CNS) of the pond snail Lymnaea stagnalis. We wished to determine whether other central neurons in the CNS of L. stagnalis express the VD1/RPD2 gene. To this end, in situ hybridization with the cDNA probe of the VD1/RPD2 gene and immunocytochemistry with antisera specific to VD1 and RPD2 (the α1-antiserum, Mab4H5 and ALMA 6) and to R15 (the α1 and 16-mer antisera) were performed on alternate tissue sections. A VD1/RPD2 neuronal system comprising three classes of neurons (A1–A3) was found. All neurons of the system express the gene. Division into classes is based on immunocytochemical characteristics. Class A1 neurons (VD1 and RPD2) immunoreact with the α1-antiserum, Mab4H5 and ALMA 6. Class A2 neurons (1–5 small and 1–5 medium sized neurons in the visceral and right parietal ganglion, and two clusters of small neurons and 5 medium-sized neurons in the cerebral ganglia) immunoreact with the α1-antiserum and Mab4H5, but not with ALMA 6. Class A3 neurons (3–4 medium-sized neurons and a cluster of 4–5 small neurons located in the pedal ganglion) immunoreact with the α1-antiserum only. All neurons of the system are immunonegative to the R15 antisera. The observations suggest that the neurons of the VD1/RPD2 system produce different sets of neuropeptides. A group of approximately 15 neurons (class B), scattered in the ganglia, immunostained with one or more of the antisera, but did not react with the cDNA probe in in situ hybridization.
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  • 60
    ISSN: 1432-0878
    Keywords: Nervous system, central ; Ganglia, invertebrate ; Octopamine ; Immunocytochemistry ; DUM neurone ; Neurosecretion ; Gryllus bimaculatus (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of octopamine-immunoreactive neurons is described using whole-mount preparations of all central ganglia of the cricket, Gryllus bimaculatus. Up to 160 octopamine-immunoreactive somata were mapped per animal. Medial unpaired octopamine-immunoreactive neurons occur in all but the cerebral ganglia and show segment-specific differences in number. The position and form of these cells are in accordance with well-known, segmentally-organized clusters of large dorsal and ventral unpaired medial neurons demonstrated by other techniques. In addition, bilaterally arranged groups of immunoreactive somata have been labelled in the cerebral, suboesophageal and terminal ganglia. A detailed histological description of octopamine-immunoreactive elements in the prothoracic ganglion is given. Octopamine-immunoreactive somata and axons correspond to the different dorsal unpaired medial cell types identified by intracellular single-cell staining. In the prothoracic ganglion, all efferent neurons whose primary neurites are found in the fibre bundle of dorsal unpaired cells are immunoreactive. Intersegmental octopamine-immunoreactive neurons are also present. Collaterals originating from dorsal intersegmental fibres terminate in different neuropils and fibre tracts. Fine varicose fibres have been located in several fibre tracts, motor and sensory neuropils. Peripheral varicose octopamine-immunoreactive fibres found on several nerves are discussed in terms of possible neurohemal releasing sites for octopamine.
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  • 61
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Enkephalin ; Skin ; Touch dome ; Merkel cells ; Dense-core granules ; Mammalian species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunogold staining failed to show met-enkephalin immunoreactivity in the Merkel cell dense-core granules of rats when examined by electron microscopy, but showed gold particle staining in the Merkel cell dense-core granules of mice and nude mice. Merkel cells of hamster, guinea pig, rabbit, cat and dog were also examined using a similar method, and different antisera dilutions. Immunogold particles were consistently found in the dense-core granules of mice and nude mice at all antisera dilutions, but not in the other species, except in the dog, where a very low labelling response was encountered. Merkel cells from skin touch domes or sinus hair follicles, did not exhibit any difference in peptide expression as far as met-enkephalin immunoreactivity was concerned. In addition, all species studied, including mice and nude mice, did not show leu-enkephalin immunoreactivity in their Merkel cell dense-core granules. It is concluded that species variability in peptide expression occurs in the Merkel cell dense-core granules, and may be closely related to the different methodologies used.
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  • 62
    ISSN: 1432-0878
    Keywords: Pheromone-biosynthesis-activating neuropeptide ; Immunocytochemistry ; Helicoverpa zea (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Production of sex pheromone in several species of moths has been shown to be under the control of a neuropeptide termed pheromone-biosynthesis-activating neuropeptide (PBAN). We have produced an antiserum to PBAN from Helicoverpa zea (Lepidoptera: Noctuidae) and used it to investigate the distribution of immunoreactive peptide in the brain-suboesophageal ganglion complex and its associated neurohemal structures, and the segmental ganglia of the ventral nerve cord. Immunocytochemical methods reveal three clusters of cells along the ventral midline in the suboesophageal ganglion (SOG), one cluster each in the presumptive mandibular (4 cells), maxillary (12–14 cells), and labial neuromeres (4 cells). The proximal neurites of these cells are similar in their dorsal and lateral patterns of projection, indicating a serial homology among the three clusters. Members of the mandibular and maxillary clusters have axons projecting into the maxillary nerve, while two additional pairs of axons from the maxillary cluster project into the ventral nerve cord. Members of the labial cluster project to the retrocerebral complex (corpora cardiaca and cephalic aorta) via the nervus corpus cardiaci III (NCC III). The axons projecting into the ventral nerve cord appear to arborize principally in the dorsolateral region of each segmental ganglion; the terminal abdominal ganglion is distinct in containing an additional ventromedial arborization in the posterior third of the ganglion. Quantification of the extractable immunoreactive peptide in the retrocerebral complex by ELISA indicates that PBAN is gradually depleted during the scotophase, then restored to maximal levels in the photophase. Taken together, our findings provide anatomical evidence for both neurohormonal release of PBAN as well as axonal transport via the ventral nerve cord to release sites within the segmental ganglia.
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  • 63
    ISSN: 1432-0878
    Keywords: Dermis ; Collagen fibers ; Extracellular matrix ; Fibronectin ; Immunocytochemistry ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of collagen types I, III, IV, and of fibronectin has been studied in the human dermis by light and electron-microscopic immunocytochemistry, using affinity purified primary antibodies and tetramethylrhodamine isothiocyanate-conjugated secondary antibodies. Type I collagen was present in all collagen fibers of both papillary and reticular dermis, but collagen fibrils, which could be resolved as discrete entities, were labeled with different intensity. Type III collagen codistributed with type I in the collagen fibers, besides being concentrated around blood vessels and skin appendages. Coexistence of type I and type III collagens in the collagen fibrils of the whole dermis was confirmed by ultrastructural double-labelling experiments using colloidal immunogold as a probe. Type IV collagen was detected in all basement membranes. Fibronectin was distributed in patches among collagen fibers and was associated with all basement membranes, while a weaker positive reaction was observed in collagen fibers. Ageing caused the thinning of collagen fibers, chiefly in the recticular dermis. The labeling pattern of both type I and III collagens did not change in skin samples from patients of up to 79 years of age, but immunoreactivity for type III collagen increased in comparison to younger skins. A loss of fibronectin, likely related to the decreased morphogenetic activity of tissues, was observed with age.
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  • 64
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    Cell & tissue research 270 (1992), S. 113-124 
    ISSN: 1432-0878
    Keywords: Dopamine ; Nervous sytem, insect ; Ganglia, invertebrate ; Immunocytochemistry ; Schistocerca gregaria (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of dopamine-like immunoreactivity in somata and neurites within the thoracic and abdominal nervous system of the locust Schistocerca gregaria was mapped using two polyclonal antibodies. The prothoracic ganglion contains three bilateral pairs of immunoreactive somata. Two of these lie close to the root of the anterior connective while the third lies between the somata of anterior and common inhibitory motor neurones. The primary neurites of the third pair have a distinctive branching pattern that can be followed through the neuropile and gives rise to a large descending axon. The mesothoracic ganglion has a single pair of antero-lateral immunoreactive somata but the metathoracic and fourth abdominal ganglia have none. The fifth, sixth, and seventh abdominal ganglia each have one pair of somata which are situated at the root of the sternal nerve while the terminal ganglion has a similar pair in the eighth neuromere only. Seven to ten immunoreactive axons enter each ganglion from each of the connectives. Some of these can be traced along the longitudinal tracts that traverse the neuropile. In each ganglion there is one axon in the median dorsal tract and two in ventral median tract. In the meso- and metathoracic ganglia an additional large axon is seen in lateral dorsal tract and dorsal intermediate tract. The axons in median dorsal, and dorsal intermediate tracts send out long ventro-lateral and ventro-medial branches which extend throughout much of the neuropile. Those in median ventral tract send markedly varicose branches to the ventral and dorsal edges of the medial neuropile.
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  • 65
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    Cell & tissue research 270 (1992), S. 339-352 
    ISSN: 1432-0878
    Keywords: Endocrine pancreas ; Ontogeny ; Regulatory peptides ; Immunocytochemistry ; Dicentrarchus labrax (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the endocrine pancreas of the teleost sea bass (Dicentrarchus labrax, L.) was examined from hatching to 61 days, using the peroxidase-antiperoxidase technique for light microscopy. Mammalian and bonito insulin (mI and bI)-, salmo somatostatin-25 (SST-25)-, somatostatin-14 (SST-14a and b)-, glucagon-, bovine pancreatic polypeptide (PP)-, peptide tyrosine-tyrosine (PYY)- and salmo neuropeptide Y (NPY)-like immunoreactivity was demonstrated. Four ontogenetic stages were established according to the organization and immunostaining of the endocrine cells. One cell strand or primordial cord showing mI/bI- and SST-25/SST-14a-like immunoreactivity was first found at hatching in the dorsal epithelium of the anterior zone of the midgut (stage 1). One primitive islet, comprising outer SST-25/SST-14a- and inner mI/bI- and SST-14a/ SST-14b-immunoreactive cells, was found in 2- to 5-day-old larvae (stage 2). One single islet, in which glucagon-immunoreactive cells appear in the periphery, was found in larvae from 9 to 20 days after hatching (stage 3). One big islet containing, in addition, PP-immunoreactive cells in the outer region and slender cell processes which showed PYY-like immunoreactivity, was found from 25 to 61 days after hatching. During this period, primordial islets, composed of SST-25- and bI-immunoreactive cells, and clustered or isolated pancreatic endocrine cells, close to the pancreatic duct, as well as small and intermediate islets (secondary islets), in which glucagon, PP, PYY and NPY seem to be co-localized, were progressively found (stage 4). The origin of the endocrine pancreas of sea bass, and the ontogenetic and phylogenetic significance, are discussed.
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  • 66
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    Cell & tissue research 270 (1992), S. 383-393 
    ISSN: 1432-0878
    Keywords: Gonadotropin-releasing hormone ; Immunocytochemistry ; Annual cycle-Mink ; Mustela vison
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of gonadotropin-releasing hormone-immunoreactive neurons and processes was mapped in the female mink brain using coronal, horizontal and sagittal sections. Perikarya were found along a ventral continuum including the olfactory tubercle, the diagonal band of Broca, the lateral septum, the preoptic and anterior hypothalamic area and the mediobasal hypothalamus; 80% of the perikarya were counted in the mediobasal hypothalamus. Fibres were mainly observed in the organum vasculosum of the lamina terminalis and the median eminence. A few processes terminated in the ependymal cells lining the third and lateral ventricles. The total number of immunoreactive perikarya was the highest in the brains of females sacrificed in July; it then significantly decreased until December. This variation is discussed in relation to the annual breeding cycle.
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  • 67
    ISSN: 1432-0878
    Keywords: Ameloblasts ; Differentiation ; Proliferation ; Bromodeoxyuridine ; Enamel matrix proteins ; Immunocytochemistry ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A double-staining immunocytochemical technique was used for the simultaneous detection, at the light- and electron-microscopical level, of proliferating bromodeoxyuridine (BrdU)-labelled cells and enamel protein (EP)-producing cells in the inner enamel epithelium (IEE) of rat tooth germ. BrdU-positive cells were found in the region of the IEE close to the cervical loop and never displayed EP-like immunoreactivity. BrdU-immunoreactivity was confined to the nucleus of replicating cells. In contrast, epithelial cells displaying EP-like immunoreactivity were found in the region of the forming dental cusp and were consistently BrdU-negative. EP-like immunoreactivity was detectable in the cytoplasmic compartments involved in the exocrine secretion pathway and in the extra-cellular matrix close to EP-immunoreactive cells. These data support the view that withdrawal from the cell cycle in the IEE is a temporal prerequisite for acquiring the functional competence of secreting EP. Moreover, cycling cells and secretory cells in the IEE constitute two separate compartments that are spatially defined, and that exhibit clear-cut staining patterns with respect to BrdU- and EP-immunoreactivity, respectively. We thus propose that BrdU-incorporation and EP-production may be used as specific markers of the differentiation of the IIE cells in studies of the possible role of growth factors, their receptors and oncoproteins in this tissue.
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  • 68
    ISSN: 1432-0878
    Keywords: Neuropeptides ; Neuropeptide Y ; FMRFamide ; Immunocytochemistry ; Telencephalon ; Thalamus ; Salmo salar (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The colocalization of the peptides neuropeptide Y (NPY) and Phe-Met-Arg-Phe-NH2 (FMRFamide) in the brain of the Atlantic salmon was investigated with double immunofluorescence labeling and peroxidase-antiperoxidase immunocytochemical techniques. Colocalization of NPY-like and FMRE amide-like immunoreactivities was observed in neuronal cell bodies and fibers in four brain regions: in the lateral and commissural nuclei of the area ventralis telencephali, in the nucleus ventromedialis thalami, in the laminar nucleus of the mesencephalic tegmentum, and in a group of small neurons situated among the large catecholaminergic neurons in the isthmal region of the brainstem. All cell bodies in these nuclei were immunoreactive to both NPY and FMRF. We consistently observed larger numbers of FMRF-immunoreactive than NPY-immunoreactive fibers. In the nucleus ventromedialis thalami NPY- and FMRFamide-like immunoreactivities were colocalized in cerebrospinal fluid (CSF)-contacting neurons. NPY-immunoreactive, but not FMRF-immunoreactive, neurons were found in the stratum periventriculare of the optic tectum, and at the ventral border of the nucleus habenularis (adjacent to the nucleus dorsolateralis thalami). Neurons belonging to the nucleus of the nervus terminalis were FMRF-immunoreactive but not NPY-immunoreactive. The differential labeling indicates, as do our cross-absorption experiments, that the NPY and FMRFamide antisera recognize different epitopes. Thus, it is probable that NPY-like and FMRFamide-like substances occur in the same neurons in some brain regions.
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  • 69
    ISSN: 1432-0878
    Keywords: Ganglia, invertebrate ; Neurosecretory cells ; DUM neurone ; Neurohemal organs ; Heart ; Immunocytochemistry ; Locusta migratoria (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Three antisera were used to study the distribution and anatomy of bovine pancreatic polypeptide (BPP)-like/FMRFamide-like immunoreactive neurones within the unfused abdominal ganglia of the migratory locust, Locusta migratoria. All the antisera used stained two or more clusters of perikarya, localized anteriorly and posteriorly near the midline within each unfused abdominal ganglion. Double labelling experiments with intracellular dye injection, or differential backfilling, combined with subsequent immunostaining were carried out to identify these neurones. Two of the antisera (antisera 1 and 2, both raised against FMRFamide) stained three groups of midline neurones, located anterior dorsal, anterior ventral and posterior dorsal within the ganglion. Neurones of the former of these two clusters projected via the anterior median nerve to a neurohaemal organ. The posterior cluster of midline cells comprised immunopositive perikarya all but one of which also projected via the anterior median nerve to innervate the neurohaemal organ. Double labelling with Lucifer yellow and antisera 1 and 2 showed that the remaining neurone was the previously identified doral unpaired median (DUM)heart1 neurone. The third antiserum (AK141), also raised against FMRFamide, stained neurones within an anterior dorsal cluster, and in a posterior cluster. Double labelling with differential Co2+/Ni2+-backfilling and the antiserum 3 (AK141) demonstrated that the large neurones of both clusters belonged to the population of bilaterally projecting neurones (BPNs), including the DUMheart1 neurone. Since the antisera cross-react with BPP and fail to label neurones when preadsorped with BPP or FMRFamide, we conclude that the labelled neurones contain polypeptides of the FMRFamide/BPP-family.
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  • 70
    ISSN: 1432-0878
    Keywords: Corpuscles of Stannius ; Stanniocalcin ; Immunocytochemistry ; Western blot ; Amia calva (Holostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We used an antiserum against salmon stanniocalcin in an immunohistochemical, immunocytochemical, and Western blot analysis of bowfin (Amia calva) corpuscles of stannius. The bowfin is one of two extant holostean species with ancient ancestral links to modern-day bony fishes. The corpuscles of Stannius (white corpuscles) of the bowfin were scattered throughout much of the kidney among the adrenocortical homolog (yellow corpuscles) but could be distinguished from the adrenocortical homolog by their positive staining with both the periodic acid-Schiff reaction and a salmon stanniocalcin antiserum. Immunoreactivity was confined to cytoplamic granules and was absent when the antiserum was blocked with salmon stanniocalcin or with a crude extract of bowfin corpuscles of Stannius. When bowfin corpuscle-of-Stannius extracts were subjected to sodium dodecyl sulphate electrophoresis and Western blot analysis, two closely spaced bands were evident (43–45 kDa). Staining of both bands was abolished by pre-absorption of the antiserum with salmon stanniocalcin. In comparison to salmon stanniocalcin, the reputed bowfin hormone migrated faster in gels, suggesting a smaller apparent size. The purification of bowfin stanniocalcin should yield important new information regarding the evolution of this unique calcium-regulating hormone.
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  • 71
    ISSN: 1432-0878
    Keywords: Histamine ; Biochemistry ; Immunocytochemistry ; Retina ; Photoreceptors ; Paraboloid ; Turtle, Pseudemys scripta (Chelonia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A combination of immunocytochemical and biochemical methods was used to study histamine in the turtle retina. Histamine-like immunoreactivity was localized within paraboloids of certain cone photoreceptors by use of two different antisera directed against histamine. Preincubation of eyecups in Ringer's containing 10 μM histamine selectively increased the immunoreactivity of these photoreceptor paraboloids. The present localization of histamine in paraboloids indicated that, although histamine is in photoreceptors of the turtle retina, it may play some metabolic or neuromodulatory role, and not function as a neurotransmitter.
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  • 72
    ISSN: 1432-0878
    Keywords: Alcohol dehydrogenase (ADH) ; Oogenesis ; Vitellogenesis ; Yolk ; Immunocytochemistry ; Drosophila melanogaster (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The use of monoclonal antibodies against Drosophila alcohol dehydrogenase (ADH) provides a powerful tool in the analysis of the tissue and temporal patterns of Adh gene expression. Immunocytochemical techniques at the light- and electron-microscopic levels have been used to determine the distribution of ADH in the ovarian follicles of D. melanogaster during oogenesis. In the early stages of oogenesis, small amounts of ADH are detectable in the cystocytes. At the beginning of vitellogenesis (S7), ADH appears to be located mainly in the nurse cells. From stage S9 onwards, the ADH protein is evenly distributed in the ooplasm until the later stages of oogenesis (S13–14), when multiple ADH-positive bodies of varying size appear in the ooplasm. This change in distribution is a result of the compartmentalization of the ADH protein within the glycogen yolk or β-spheres. Yolk becomes enclosed within the lumen of the primitive gut during embryonic development, and thus our results suggest a mechanism for the transfer of maternally-inherited enzymes to the gut lumen via yolk spheres.
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  • 73
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    Cell & tissue research 268 (1992), S. 277-281 
    ISSN: 1432-0878
    Keywords: Lung ; Elastin-binding protein ; Lectins ; Galactose ; Monocytes ; Immunocytochemistry ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 67 kDa elastin-binding protein (RL-67EBP) has been isolated from neonatal rat lungs by the use of an elastin-coupled affinity column, followed by elution with either lactose or synthetic elastin hexapeptide (VGVAPG), and immunohistochemistry has been used on perinatal rat lungs to determine the tissue localization of this protein. No immunoreactive structures occur in fetal lungs, or in the lungs of day-1 and-4 neonates. On day-7 after birth, immunoreactive cells appear in the subepithelial connective tissue of the intrapulmonary airways, from day-10 on, these cells become evenly distributed in the alveolar parenchyma. Occasionally, some cells occur in the alveolar air space, being free from the surface of the alveolar septum. Unpermeabilized cells obtained by bronchoalveolar lavage, show cell surface immunoreactivity, indicating that RL-67EBP is expressed on the surface membrane of the cells. From these findings, it is suggested that the immunoreactive cells are blood-borne monocytes, and that RL-67EBP may function as an elastin peptide receptor by which monocytes mobilize through interstitial connective tissue during their migration from blood to alveolar air space, where they eventually differentiate into alveolar macrophages.
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  • 74
    ISSN: 1432-0878
    Keywords: Neurosecretory cells ; Brain ; Immunocytochemistry ; Prothoracicotropic hormone ; Insulin-related peptide ; Neuroparsins ; Locusta migratoria (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using a monoclonal antibody directed against a synthetic pentadecapeptide corresponding to the N-terminus of the prothoracicotropic hormone (PTTH) of Bombyx mori, we report the presence of immunoreactive molecules in a large number of median neurosecretory cells of the pars intercerebralis of the migratory locust, Locusta migratoria. These cells correspond to the A1 cell type which we show to contain also neuroparsins, a family of predominant neurohormones of the migratory locust. In contrast, PTTH-like molecules are absent from A2 cells of the pars intercerebralis which contain Locusta insulin-related peptide (LIRP). Developmental studies show the presence of PTTH-related substances in neurosecretory cells of Locusta migratoria from late embryogenesis to adult development, including ageing vitellogenic female adults.
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  • 75
    ISSN: 1432-0878
    Keywords: Sodium influx-stimulating (SIS) peptide ; Na+ transport ; In situ hybridization ; Immunocytochemistry ; Lymnaea stagnalis (Mollusca)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The functional morphology of the neuroendocrine system producing sodium influx-stimulating (SIS) peptide in the pond snail, Lymnaea stagnalis, was studied by in situ hybridization and immunocytochemistry. The SIS-peptide, which is 76 amino acids long, stimulates sodium uptake from the ambient medium. Two synthetic DNA probes were used for in situ hybridization. The nucleotide sequences were chosen from the cDNA structure; they encode amino acids 8–17 and 64–73, respectively. SIS-peptide sequences 10–20 and 67–76 were synthesized and antibodies were raised to them and affinity-purified. In addition to these antibodies, a monoclonal antibody raised to a bioactive, high-pressure liquid chromatography (HPLC)-purified brain extract was used for immunocytochemistry. Paraffin sections of central nervous systems and of whole snails were studied. The SIS-peptide system could be identified as the previously described yellow cell (YC) system by comparing alternate sections treated with the DNA probes, stained with the antibodies, or stained with alcian blue-alcian yellow. SIS-peptide neurons (∼45) occur in the ganglia of the visceral ring and in the proximal parts of visceral nerves. Axons run in the nerves of these and in several nerves of other ganglia. Numerous axon branches penetrate the perineurium forming a vast central neurohemal area. The SIS-peptide system innervates the pericardium, the nephridial gland, the reno-pericardial canal, the ureter, the spermoviduct and gonadal acini, the anterior aorta, the ventral buccal artery, and the penis protractor muscle. The morphology of the system is discussed in relation to the process of sodium ion uptake from the ambient medium and from pro-urine, and to that of regulating blood pressure. In the central nervous system and other organs, neurons and axons not labeled with the DNA probes, but immunoreactive to one or two of the antibodies, were observed. It seems unlikely that these elements are functionally related to the SIS-peptide system.
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  • 76
    ISSN: 1432-0878
    Keywords: Pancreas, endocrine ; Immunocytochemistry ; Muscarinic acetylcholine receptor ; Acetylcholine ; Somatostatin ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemical application of the antimuscarinic acetylcholine receptor antibody M35 to pancreas tissue revealed the target areas for the parasympathetic nervous system. Immunoreactivity in the endocrine pancreas was much higher than that in the exocrine part. Moreover, the endocrine cells at the periphery of the islets of Langerhans displayed the highest level of immunoreactivity. Based on these findings in the mantle of the islets, two types of islets have been distinguished: type-I islets with intensely stained mantle cells, and type-II islets with a much lower concentration of these cells. On average, type-I islets were larger (244.8 μm±6.1 SEM) than type-II islets (121.5 μm±3.8 SEM). M35-immunoreactivity was present on the majority of D cells, which were characterized by their immunoreactivity to somatostatin [of 446 D cells 356 (79.8%) were M35-immunopositive]. However, only a small proportion of the intensely stained mantle cells belonged to the D cell population. Therefore, it is concluded that the majority of the intensely stained mantle cells represent glucagon-secreting A and/or pancreatic polypeptide-secreting F cells. The intensity of M35-immunoreactivity at the periphery and central core of the islets paralleled the density of cholinergic innervation, suggesting a positive correlation between the intensity of cholinergic transmission and the number of muscarinic acetylcholine receptors at the target structures. The present study further revealed some striking parallels for the muscarinic acetylcholine receptor characteristics between the (endocrine) pancreas and the central nervous system.
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  • 77
    ISSN: 1432-0878
    Keywords: Molluscan insulin-related peptide ; Neuropeptide ; Light green cells ; Differential gene expression ; Immunocytochemistry ; In situ hybridization ; Lymnaea stagnalis (Mollusca)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pond snail Lymnaea stagnalis, the growth regulating system consists of (1) about 200 neuroendocrine light green cells, located in four clusters in the cerebral ganglia, and (2) the paired canopy cells, located in the lateral lobes. These cells express genes encoding the molluscan insulin-related peptides (MIPs). Six MIP genes have previously been identified. Four of these (I, II, III and V) are expressed in the light green cells and the canopy cells. The MIP-VI gene is a pseudogene. In the present in situ hybridization study, using oligonucleotide probes specific to the transcripts of MIP-I,-II,-III,-IV, and-V, no signal was obtained with the MIP-IV probe, indicating that gene IV is also a pseudogene. With the other four probes, two types of light green cells were distinguished. Type-A cells express all four MIP genes, whereas type-B cells do not (or only faintly) express the MIP-I gene. Gene III is relatively strongly expressed in type-B cells. Genes II and V are moderately expressed in both cell types. Type-A cells are mainly located in the periphery of the clusters, whereas type-B cells are present in the center. The canopy cell resembles type-A light green cells. The expression levels of the MIP-II and MIP-V genes are low in the canopy cell. The expression pattern of the MIP genes correlates with the staining pattern of the anti-MIP-C antibody, which has been raised to a synthetic C-fragment shared by MIP-I,-II and-V. Type-A cells stain more intensely with the antibody than type-B cells.
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  • 78
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    Cell & tissue research 270 (1992), S. 15-23 
    ISSN: 1432-0878
    Keywords: Allatostatin ; Corpus allatum inhibitors ; Immunocytochemistry ; Brain ; Neuroendocrine complex ; Diploptera punctata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A monoclonal antibody against allatostatin I was used to demonstrate the allatostatin-immunoreactive pathways between the brain and the corpus cardiacum-corpus allatum complex in the adult cockroach Diploptera punctata. The antibody was two to three orders of magnitude more sensitive to allatostatin I than to the other four known members of the allatostatin family. Whole and sectioned brains in which immunoreactivity was localized with horseradish peroxidase-H2O2-diaminobenzidine reaction showed strongly immunoreactive cells in the pars lateralis of the brain with axons leading to and arborizing in the corpus cardiacum and the corpus allatum. Although many neurosecretory cells of the pars intercerebralis project to the corpora allata only, four strongly immunoreactive cells were evident here (two pairs on either side), and these did not project to the corpus cardiacum and corpus allatum but rather terminated within the protocerebrum in areas in which lateral cells also formed arborizations. Immunoreactivity was found in many other cells in the brain, especially in the tritocerebrum.
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  • 79
    ISSN: 1573-9171
    Keywords: EPR ; radical ; fluorine ; conformation ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract EPR spectra of radical adducts of phosphonyl radicals with 2-hydroperfluoro-4-methyl- and 4,4-dimethyl-2-pentene have been studied. The molecular mechanics method has been used to determine the preferred conformation of the (CF3)2CF-CF-HCF3P(O)(OMe)2 radical. The eclipsed conformation of the C–P bond and 2p z -orbital of an unpaired electron is stabilized due to steric factor and hyperconjugation.
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  • 80
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fatty acids and bile acids ; Fluorogenic precolumn derivatization ; 2-Bromoacetyl-6-methoxynaphthalene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of 2-bromoacetyl-6-methoxynaphthalene as a fluorogenic labelling reagent in pre-column derivatization for the HPLC separation of biologically active carboxylic acids (fatty acids and bile acids) has been investigated. The compound reacts (30 min. at 70°C) with carboxylic acids to give fluorescent esters that can be separated by reversedphase HPLC and detected at λ ex. 300 nm, λ em. 460 nm. The experimental conditions for the derivatization and chromatographic separation are discussed. Applications to the determination of valproic acid and chenodeoxycholic acid in pharmaceutical formulations are described.
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  • 81
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Valproic acid ; Simultaneous determination of anticonvulsants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The derivatizing procedure of Moody et al. [20] for valproic acid has been simplified and applied to the simultaneous HPLC determination of valproic acid (VPA), barbital (B), primidone (PRM), phenobarbital (PB) and carbamazepine (CBZ) in serum or plasma of epileptic patients. The sample is deproteinized with acetonitrile containing esterification agents and an aliquot of the supernatant is heated to 70°C for 15 min with 4-bromophenacyl bromide. The reaction mixture is analysed on a C18 column at ambient temperature, with gradient elution and with detection at 205 nm. The time required for the chromatographic analysis is 13 min; identification is based on retention time and quantification is by peak area determination with an internal standard. The calibration curves show good linearity in the range 6.25 to 100 mg/L. The detection limits at a signal: noise ratio ≥3, ranged from 1 mg/L for B and CBZ to 2–3 mg/L for PRM, PB and VPA. The method described for the simultaneous determination of the five drugs in the same plasma pool, correlated well with isocratic HPLC methods specific for each drug. The simultaneous procedure described allows a reproducible (CVs≤6.5% within run) and rapid (25 min for sample preparation: 13 min for chromatographic run) therapeutic monitoring of patients treated with VPA and two or more antiepileptic drugs.
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  • 82
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Porous polymer spherical packings ; Vinyl ether ; Alkali resistance ; No abnormal adsorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Spherical, porous-polymer particles for column packing in high-performance liquid chromatography were prepared by suspension copolymerization of alkylvinyl ether with triethyleneglycol divinyl ether. The hydrophobicity of the packings was easily adjusted by changing the monomer ratio. The packings showed the usual reversed-phase liquid chromatographic properties, but did not sho abnormal retention, tailing and broadening of peaks and irreversible adsorption of ionic and aromatic substances, owing to the lack of ionic or aromatic groups. In addition, the packings were stable in alkaline solutions because of the relative alkali stability of C−O−C bonds as compared with CO−O and Si−O−C bonds in conventional packings.
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  • 83
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Anion exchange ; Indirect photometric and direct conductivity detection ; Naphthalenesulfonate ; Inorganic anions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Indirect photometric and unsuppressed direct conductivity detection modes are examined using naphthalene mono-, di-, and tri-sulfonate as mobile phases for the separation of several anions such as F−, Cl−, NO2 −, Br−, NO3 −, SO4=,I−, and SCN− using a commercial anion exchange column. With all three mobile phases, conductivity detection shows better sensitivities and detection limits than indirect photometry. Conductivity detection is 5 to 16 times more sensitive than indirect photometry for all analytes. Detection limits achieved using these mobile phases are, for example, 0.04 ng and 0.1 ng for chloride ion with conductivity and indirect photometry, respectively. Both detection modes give wide linear ranges extending from at least 100 ppm to the detection limit of each anion which is generally about 0.02 ppm. Sulfur oxide anions such as dithionate and tetrathionate are separated using flow programming with naphthalenetrisulfonate as the mobile phase in less than 20 minutes. With both detection modes, desired chromatographic performance of these three eluents is achieved without pH adjustment of the mobile phase.
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  • 84
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Heat-treated milk ; Milk quality indicators ; 5-Hydroxymethyl-2-furfuraldehyde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An enhanced method of HPLC for the determination of 5-Hydroxymethyl-2-furfuraldehyde (HMF) in fluid milk was perfected. Its resolving capacity permitted the specific separation of this compound. The real concentration (μmol/l) of HMF was determined and not the HMF value, as in the colorimetric analysis, where an intermediary coloured compound (HMF-TBA) is utilised. The optimum pH condition (pH=4.0–4.2) for the mobile phase to prevent overlapping between the HMF peak and the peaks of the other compound (α and β) that coeluted with the HMF and also the optimum organic solvent content (3% or 7%) were established. This is a sensitive, quick and safe method for the determination of HMF in fluid milk.
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  • 85
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Arsenic compounds ; Polymeric styrene divinylbenzene phase ; Ion-pairing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The resolving power of an ion-pair reversed-phase liquid chromatography method, on a polymeric stationary phase (PRP-1) with an alkaline aqueous mobile phase (pH=9) containing tetrabutylammonium cation as ion-pairing agent, is compared with a traditional ion-pairing system using an octadecyl-modified silica column and a neutral aqueous mobile phase (pH=7.3). This chromatographic system (PRP-1 column) provides a rapid means for the determination of two of the most important arsenic species, arsenobetaine and arsenite. Addition of methanol (5%) to the aqueous mobile phase allows the differentation of arsenobetaine from the system peak when using UV detection.
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  • 86
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gravity-flow column chromatography ; Provitamin A determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The provitamin A content of some food samples was determined by methods involving MgO: Hyflosupercel gravityflow column chromatography (GFCC) and reversed phase high performance liquid chromatography (HPLC), the quantitation being done by external standardization (HPLC-ES) or internal standardization (HPLC-IS) with Sudan. The results obtained with α- and β-carotene in carrots, β-carotene and β-cryptoxanthin in papaya and β-carotene in tomato and kale agreed well, showing that any of the these techniques can be used, provided the analysis is done under optimum conditions. Good separation of the different provitamins using GFCC depends on the analyst's skill and visual acuity. HPLC-ES required a constant supply of provitamin standards, thus the varying purity of commercially available standards and the high instability of these compounds could pose grave problems. Due to the stability of Sudan, HPLC-IS appeared to be the method of choice although passage of the extract through a MgO: Hyflosupercel minicolumn was required prior to injection to separate chlorophylls, dihydroxy- and polyoxycarotenoids which would otherwise elute with Sudan. Nonconformity of the Sudan structure to those of the provitamins did not effect the quantitative results. The chromatographic separation, identity and quantification of the provitamins could be more easily established by using HPLC-IS, complemented with GFCC.
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  • 87
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    Chromatographia 33 (1992), S. 103-112 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Chiral separations ; Allethrin ; Cypermethrin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Liquid and gas chromatographic separations of the pyrethroid insecticides allethrin and cypermethrin have been investigated with various achiral and chiral stationary phases. Diastercomeric and enantiomeric selectivity was observed for cypermethrin on a Pirkle-type chiral LC stationary phase, but very strong interactions and therefore long retention times prevented the separation of allethrin on this phase. Trans-allethrin isomers were separated on a chiral β-cyclodextrin RP-HPLC column while cypermethrin showed some difficulties on this phase due to isomerization. Diastereomeric but no enantiomeric selectivity by GC was achieved for cypermethrin with an apolar DB 5 capillary. GC separation of the diastereomers was used to study the selective photodegradation of cypermethrin isomers after forestry applications. Chiral β-cyclodextrin-based GC phases showed some enantioselectivity for cis- and trans-allethrin isomers. A separation of the eight isomers into six partially resolved peaks was achieved by GC with a coupled column consisting of chiral permethylated β-cyclodextrin and DB 1701 as stationary phases. This combination was used to characterize allethrin formulations intended for indoor use and to investigate allethrin products formed by ozonolysis of thin films of the insecticide.
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  • 88
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    Chromatographia 33 (1992), S. 177-185 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Diuretics ; Screening and determination of diuretics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This critical review of different methods proposed for the determination and screening of diuretics is directed mainly, because of its potential application, towards highperformance liquid chromatography.
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  • 89
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    Chromatographia 33 (1992), S. 218-224 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Peak ; Pattern recognition ; Prediction interval
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary It is still difficult to determine peaks and peak boundaries properly, though peak recognition is very important for the precision of quantitative data. A new computer program overcomes these problems using a method which is adapted from human judgements. The algorithm was developed for HPLC but can also be used in other fields of analytical chemistry.
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  • 90
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Diol silica gels ; Carbohydrates ; Evaporative light scattering detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Bonded silica columns have been evaluated for their ability to separate carbohydrates and polyols. Mobile phases consisting of dichloromethane/methanol produced the best separations in comparison with the acetonitrile/water mixtures commonly used with amino columns. Of all the bonded phases tested, LiChrospher Diol silica provided the best separations, and selectivities were not very different from those obtained on the most popular system using an amino bonded phase and acetonitrile/water as eluent. In addition, diol columns with a dichloromethane/methanol eluent offer excellent stability with no Schiff’s base formation of reducing sugars. Using an evaporative light scattering detector, low limit detection is obtainable (20 ng of glucose from a column) and gradient elution is quite feasible.
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  • 91
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Porous graphitized carbon ; Ring-substituted aniline derivatives ; Electronic interactions ; Principal component analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention characteristics of 22 aniline derivatives were determined on a porous, graphitized-carbon column in unbuffered acetonitrile-water and methanol-water mixtures. Each aniline derivative gave symmetrical peaks in each eluent without buffers. Good linear correlations were found between the log k′ and the concentration of the organic component in the eluent. The slope and intercept values differed according to the type of organic modifier and the charcter, number and position of substituents, indicating the different selectivities of methanol and acetonitrile and the good separating power of the column. Multivariate mathematical-statistical calculations proved that the retention of ring-substituted aniline derivatives is mainly governed by electronic parameters and the hydrogen acceptor capacity of substituents.
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  • 92
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ion-pairing ; Furosine ; Pyridosine ; Milk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An ion-pair, reversed-phase, liquid chromatographic procedure using UV detection for quantitation of furosine is described. The standard plot was linear (r〉0.999) over a 5 ng range. An authentic synthesised sample of furosine was used for calibration. Commerical milk samples were analyzed by the described procedure.
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  • 93
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Automated peak detection ; Discrete Fourier transform ; Frequency acquisition and filtering ; Peak detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The principle of automated chromatographic peak detection and analysis software is summarized, and critical steps are systematically studied. As the only parameter to be entered is the acquisition frequency, evaluation of its effect on software performance is discussed. In the case of relatively noisy chromatograms, it is shown experimentally that numerous points per peak have to be taken, leading to quite fast computer acquisition procedures. The use of discrete Fourier transform filtration techniques can modify peak shapes and a comparative study evaluates the relative errors induced in the shapes and characteristics of the chromatographic profiles. Optimisation of filtering conditions is achieved and it is shown that for a filter position only 2% of the Nyquist frequency no deformation occurs in the chromatographic profile. Detection of the start and finish of chromatographic peaks is optimized according to a simple four step iterative procedure. In the case of simulations, the difference between the values used to simulate peaks and those calculated by the software are less than 1%.
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  • 94
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fluoropyrimidine drugs ; Pharmacokinetics of doxifluridine ; Chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A reversed phase high performance liquid chromatographic method has been developed for the simultaneous determination of the pro-drug 5′-deoxy-5-fluorouridine (5′-dFUR), its metabolite 5-fluorouracil (5-FU) and some fluorinated pyrimidines involved in the metabolic activation process of 5-FU. The method has been used to monitor the bioavailability of 5′-dFUR and 5-FU in patients undergoing anticancer chemotherapy. Serum sample treatment involves addition of internal standard (5-bromouracil), protein precipitation with saturated ammonium sulphate solution and liquid-liquid extraction with ethyl acetate-isopropanol (90 ∶ 10 v/v). Urine is simply diluted with mobile phase and injected. The average recovery from serum (at 0.5 μg/mL level) was 95.0%±1.4 for 5′-dFUR and 86.3%±3.5 for 5-FU. A linear response extending over four decades of concentration was observed. Detection limits in the low ng/ mL range were obtained using a 250 μL sample size and a 20 μL injection volume. Within-day and between-day coefficients of variation were below 4 and 10%, respectively.
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  • 95
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Flow injection analysis ; Combined flow injection/HPLC ; Carbamate pesticides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An integrated flow injection (FI)/HPLC system for the total and individual determination of carbamate pesticides (propoxur, carbofuran and carbaryl) is proposed. The determination is based on the alkaline hydrolysis of the analytes and subsequent coupling with diazotized sulphanilic acid to yield the monitored dyes with or without a prior separation step by HPLC in a C18 column. The calibration curves obtained are linear in the μg/ml range and r.s.d. values are between 0.5 and 3.7% in all instances. Injection of the sample into the FI manifold allows the total pesticide content in the sample to be screened. The manifold thus acts as a post-column reactor/detector of the chromatograph for samples with high overall carbamate content, which are also injected into the HPLC instrument. The performance was checked with contaminated water samples.
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  • 96
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; α1 glycoprotein ; Enantioseparation ; β-blocking agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The enantioselectivity of the α1 glycoprotein chiral stationary phase, Chiral AGP® has been evaluated for a number of β-blocking agents. A correlation has been found between the retention behaviour on this stationary phase and the hydrophobicity of the compounds. The separation factor α is higher for compounds that are well retained. Retention, and thus α, are also controlled by pH and the percentage of organic modifier in the mobile phase.
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  • 97
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Perfluoroalkylated polymer-gel packings ; Aromatic and fluorine-containing compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Porous, perfluoroalkylated polymer-gels for column packings in high-performance liquid chromatography (HPLC) were prepared by suspension polymerization of heptadecafluorodecyl arcylate and ethylene glycol dimethacrylate. The packings showed no abnormal retention for ionic or aromatic compounds, due to the lack of ionic or aromatic groups. In addition, the packings showed no excessive retention for strongly hydrophobic compounds which is often the case with long-chain, alkylated silica gels and polymer gels. This is due to the extremely low surface energy of perfluoroalkyl groups. Therefore, perfluoroalkylated polymer gels enable isocratic HPLC separation of solutes with significantly different hydrophobicity.
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  • 98
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Porous glass ; Surface free energy ; Film pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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  • 99
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    Chromatographia 33 (1992), S. 478-484 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Porous glass adsorbents ; Surface free energy ; Oriented adsorption of hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The relationship between the specific capacity factor (k/S, where k is the capacity and S is the surface area of the sorbent, in m2) in the liquid chromatography of aromatic hydrocarbons and the adsorption energy (-°GA) has been investigated. The previously published results, based on the calculation of the work of adhesion (WSA) from contact angles, were re-examined and a new hypothesis on interactions at interfaces was employed. Direct proportionality has been found between k/S and-°GA, which allows prediction of the chromatographic behavior of adsorbates on sorbents. The surface free energy components were calculated in order to determine-°GA in terms of the work of adhesion. The dispersion component of the surface free energy of glass was obtained from the adsorption isotherm of n-octane and it was found that the hydrocarbon molecules are adsorbed in an oriented position. The contact angles of liquids on the outer surface of porous solids do not yield reliable values of WSA and of the surface free energy components. A higher intermolecular attraction increases WSA and decreases the contact angle in pores.
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  • 100
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Adenosine and some metabolites ; Extraction from brain tissue ; Quantitative determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An analytical procedure has been developed for the assay of adenosine and some metabolites in brain tissue extracts of rats. This paper reports the extraction method, the technique adopted to avoid enzymatic transformations and the chromatographic conditions for the identification and quantitation of these nucleosides and bases. Peaks in the chromatograms of brain tissue extracts were identified by retention times, absorbance ratios of reference compounds and by enzymatic peak-shift.
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