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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 74 (1995), S. 115-119 
    ISSN: 1570-7458
    Schlagwort(e): wheat ; aphids ; hydroxamic acids ; DIMBOA ; DIMBOA-glucoside ; EPG ; electrical penetration graph ; feeding deterrents ; antixenosis ; plant resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Feeding behaviour of five species of cereal aphids in wheat seedlings differing in hydroxamic acid (Hx) levels, was monitored via electrical penetration graphs (EPG). Aphid species could be grouped as sensitive to the feeding deterrent effect of Hx in the seedlings (Rhopalosiphum padi, Schizaphis graminum, Sitobion avenae, andMetopolophium dirhodum) or insensitive to them (Rhopalosiphum maidis). However, when feeding behaviour was studied in artificial diets containing Hx, all species were equally sensitive to Hx. The behavour ofR. maidis was further compared with that ofR. padi through detailed EPG analysis. It was found that the insensitivity ofR. maidis to Hx in seedlings may be due to a feeding strategy avoiding contact with the compounds by decreasing the number of cellular punctures in live tissues other than sieve elements during its way to the phloem.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 74 (1995), S. 283-294 
    ISSN: 1570-7458
    Schlagwort(e): hypersensitivity ; Hessian fly ; plant resistance ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Hessian flyMayetiola destructor (Say) larvae are able to obtain food from their host plant without inflicting mechanical damage to the plant surface, apparently by secreting substances which elicit release of nutrients from plant cells surrounding the feeding site. Cells of fully susceptible plants retain their normal appearances, while in resistant plants extensive areas of cellular collapse occur. These responses indicate that hypersensitivity is the basis of wheat's resistance to the Hessian fly. The fly's feeding mechanism more closely resembles that of a pathogen than of a phytophagous insect; correspondingly, both the genetic relationship and resistance mechanism of the host plant to the parasite are of the sorts commonly associated with bacterial and fungal pathogens.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 227-230 
    ISSN: 1570-7458
    Schlagwort(e): Rhopalosiphum padi ; cereal aphids ; wheat ; induced responses ; feeding site
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 157-164 
    ISSN: 1570-7458
    Schlagwort(e): plant resistance ; antibiosis ; tolerance ; antixenosis ; Russian wheat aphid ; wheat ; Homoptera ; Aphididae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Russian wheat aphid, Diuraphis noxia (Mordvilko), is one of the most important aphid pests of wheat, Triticum aestivum L., worldwide. Among the various pest management options, plant resistance is an economical management tactic to control D. noxia in cereal crops such as wheat. Researchers have identified D. noxia resistant germplasm and it has been incorporated into wheat. This study compared D. noxia resistance between the ‘Betta’ wheat isolines Betta-Dn1, Betta-Dn2, and Betta-Dn5 and their corresponding donor gene plant introduction (PI) lines PI 137739 (Dn1), PI 262660 (Dn2), and PI 294994 (Dn5). Although the Betta isolines and PI lines showed D. noxia resistance when compared with Betta wheat, the degree of resistance in the isolines to D. noxia was different from their corresponding PI donors. Aphid number, aphid fecundity, and biomass per aphid were not different between Betta-Dn1 and PI 137739 or Betta-Dn2 and PI 262660; however, the same parameters were significantly lower on PI 294994 compared with Betta-Dn5. This indicated that aphid resistance in PI 137739 and PI 262660 was probably governed by a single dominant gene, while the resistance in PI 294994 was controlled by more than one gene. Additionally, plant biomass reduction was aphid density dependent, which suggested that use of appropriate aphid infestation level is important when using plant biomass reduction as an indicator of resistance. Plant resistance categorization showed that there was no detectable difference in antixenosis among the seven lines evaluated. However, the higher aphid fecundity observed on PI 262660 compared with PI 137739 and PI 294994, in addition to no significant differences among the three PIs in plant biomass reduction, suggested PI 262660 was a tolerant line, while PI 137739 and PI 294994 were antibiotic lines. Plant tolerance could not be elucidated among the three Betta isolines using aphid fecundity and plant biomass reduction as indicators.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 111-118 
    ISSN: 1570-7458
    Schlagwort(e): leaf surface wax ; probing behavior ; nymphoposition ; Russian wheat aphid ; wheat ; barley ; oat ; Homoptera ; Aphididae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of cereal leaf surface wax on Diuraphis noxia (Mordvilko), the Russian wheat aphid, probing behavior and nymphoposition was evaluated. Ultrastructure of leaf epicuticular wax from wheat (Triticum aestivum L.) c.v. ‘Arapahoe’ and ‘Halt’ was different from barley (Hordeum vulgare L.) c.v. ‘Morex’, and oat (Avena sativa L.) c.v. ‘Border’. Both wheat cultivars had similar rod-shaped epicuticular wax, while barley and oat plants had flakes. The chemical composition comparison of gas chromatograms also indicated that the extract of the two wheat cultivars had similar pattern of peaks, while the barley and oat leaves had similar peaks. Cereal variety significantly affected aphid probing behavior (P 〈 0.05), but wax removal using ethyl ether swab did not (P 〈 0.05). Aphids initiated significantly more probes on Border oat leaves than on Morex barley irrespective of wax removal, although total probing duration per aphid was not significantly different among the four cereals examined. Accumulative salivation duration per aphid on oat leaves with wax was significantly longer than other cereal leaves with wax, while accumulative ingestion duration per aphid on Arapahoe wheat and Morex barley was significantly longer than on oat. Nymphoposition of D. noxia on cereal leaves maintained on the benzimidazole-agar medium showed that aphids produced a greater number of nymphs on Morex barley and less on Border oat leaves, although wax removal did not affect aphid nymphoposition. Removal of leaf epicuticular waxes from the 4 cereal genotypes using ethyl ether swab indicated that the influence of wax on plant resistance to D. noxia probing and reproduction was limited. Morex barley was the most favorable, while Border oat was the least favorable cereal host of D. noxia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 111-114 
    ISSN: 1570-7458
    Schlagwort(e): sieve element ; salivation ; aphid ; plant resistance ; wheat ; Sitobion fragariae ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Extended sieve element salivation (E1 waveform in the electrical penetration graph) is a characteristic activity during early sieve element punctures, particularly in resistant plants. In order to explore a chemically-mediated mechanism of resistance associated with sieve element salivation, we compared the pattern of feeding behaviour of the aphid, Sitobion fragariae (Walker), on two cultivars of the wheat Triticum aestivum L., with different concentrations of hydroxamic acids (Hx). During 24 h of electronic monitoring, aphids dedicated over 50% of the total time to phloem ingestion from the sieve elements. Total time allocated to E1 in the experiment, time to first E1 within the experiment, time allocated to E1 before a sustained phloem ingestion (E2) and the contribution of sieve element salivation to the phloem phase (E1/[E1+E2]) were significantly higher in the high-Hx cultivar. The increased salivation in plants with higher contents of Hx suggests the existence, at least in this system, of a chemically-mediated sieve element constraint.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 2 (1968), S. 296-298 
    ISSN: 1432-0827
    Schlagwort(e): Calcium ; Lipid ; Bacteria ; Calcification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé On a fait ce travail pour determiner si le facteur responsable pour la liaison de calcium par un calcifableBacterionema matruchotii est dans la fraction lipide de la cellule. Des cellules congelees et sechees ont ete extraites par le chloroform-methanol. La fraction de chloroform-methanol, les cellules extraites et les cellules non traitees ont ete examinees pour la liaison de calcium. La fraction du chloroform-methanol et les cellules non traitees avaient la liaison de calcium. Les cellules extraites n'en avaient pas.
    Kurzfassung: Zusammenfassung Diese Arbeit wurde durchgeführt um festzustellen, ob sich der Faktor für die Calcium-bindung, durch das calcifizierendeBacterionema matruchotii, in der Lipoidfraktion befindet. Die lyophiilisierten Zellen wurden mit Chloroform-Methanol extrahiert. Die Chloroform-Methanol-Fraktion, die extrahierten Zellen, sowie die nicht behandelten Zellen wurden auf eine Calciumbindung hin untersucht. Die Chloroform-Methanol-Fraktion und die nicht behandelten Zellen demonstrierten eine Calciumbindung. Die extrahierten Zellen hingegen nicht.
    Notizen: Abstract This work was done to determine whether the factor responsible for calcium binding by a calcifiableBacterionema matruchotii is in the lipid fraction of the cell. Freeze-dried cells were extracted with chloroform-methanol. The chloroform-methanol fraction, the extracted cells and untreated cells were examined for calcium binding. The chloroform-methanol fraction and the untreated cells bound calcium. The extracted cells did not.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 4 (1969), S. 260-268 
    ISSN: 1432-0827
    Schlagwort(e): Cartilage ; Histochemistry ; Staining ; Protein ; Polysaccharide ; Calcification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Des coupes de cartilage épiphysaire frais de jeunes rats, effectuées à la main, sont colorées à pH=4,5 dans des solutions à 0,01% de divers colorants cationiques, appartenant aux groupes de la thiazine, oxazine, azine, triphénylméthane, acridine, et phthallocyanine. Les granules intracellulaires métachromatiques, mises en évidence antérieurement par le bleu de toluidine, sont également identifiées à l'aide de l'azur A, le bleu de méthylène et le bleu de crésyl. Les granules se colorent moins bien à la thionine, le rouge neutre, la safranine O, le bleu de toluylène et l'acridine orange. Dans les conditions utilisées, la matrice de la zone de réserve et la matrice de la zone hypertrophique inférieure (en voie de calcification) se colorent, alors que les matrices des zones prolifératives et hypertrophiques supérieures ne prennent pas les colorants. La gallocyanine, le violet cristal, la fuchsine basique, l'azocarmin B, le bleu de gallamine et la bleu alcian ne se colorent pas ou donnent des réactions colorées différentes de celles décrites ci-dessus. Il semble que le pK et le poids moléculaire des colorants jouent un rôle important, mais ils ne paraissent pas être les seuls facteurs intervenant dans la coloration des granules. Un changement, lié à la calcification, semble intervenir au niveau du matériel métachromatique (probablement des polysaccharides protéiques), aussi bien dans la matrice que les cellules cartilagineuses épiphysaires.
    Kurzfassung: Zusammenfassung Handpräparierte Schnitte von frischem Epiphysenknorpel junger Ratten wurden bei einem pH von 4,5 in 0,01% igen Lösungen verschiedener kationischer Farbstoffe folgender Klassen gefärbt: Thiazin, Oxazin, Azin, Triphenylmethan, Acridin und Phthalocyanin. Die intracellulären β-und γ-metachromatischen Granula, erstmals mit Toluidinblau im frischen Gewebe nachgewiesen, konnten auch gut mit Azur A, Methylenblau und Brillantkresylblau dargestellt werden. Die Granula konnten ebenfalls, aber weniger gut, mit Thionin, Neutralrot, Safranin D, Toluylenblau und Acridinorange gefärbt werden. Unter diesen Färbungsbedingungen werden die inaktive Matrixzone und die untere hypertrophische (verkalkende) Matrixzone angefärbt, während die proliferative und die obere hypertrophische Matrixzone sich nicht färben. Gallocyanin, Kristallviolett, basisches Fuchsin, Azokarmin B, Gallaminblau und Alzianblau färbten entweder gar nicht, oder gaben ein anderes als das obenbeschriebene Färbemuster. Es wird vorgeschlagen, daß das pK und das Molekulargewicht der Farbstoffe wichtig aber nicht unbedingt die einzigen Faktoren sind, die die Färbung der Granula bestimmen. Die Resultate zeigen, daß eine Veränderung im metachromatischen Material (vermutlich Proteinpolysaccharide) vorliegt, und zwar sowohl in der Matrix als in den Zellen des Epiphysenknorpels; diese Veränderung scheint im Zusammenhang mit der Verkalkung zu stehen.
    Notizen: Abstract Hand-cut sections of fresh epiphyseal cartilage from young rats were stained at pH 4.5 in 0.01% solutions of various cationic dyes of the thiazine, oxazine, azine, triphenylmethane, acridine, and phthallocyanin classes. The intracellular β-and γ-metachromatic granules, previously demonstrated in fresh tissues with toluidine blue, were also demonstrated well with azure A, methylene blue, and brilliant cresyl blue. The granules were also demonstrated, but not as well, by thionin, neutral red, safranin O, toluylene blue, and acridine orange. Under the conditions of staining, the reserve zone matrix and the lower hypertrophic (calcifying) zone matrix stained, whereas the proliferative and upper hypertrophic zone matrix did not stain. Gallocyanin, crystal violet, basic fuchsin, azocarmine B, gallamine blue, and alcian blue either did not stain, or gave a different pattern of staining from that described above. It is suggested that the pK and molecular weight of the dyes are important, but not necessarily the only factors in determining the staining of the granules. The results indicate that there is a change in the metachromatic material (presumably proteinpolysaccharide) in both the matrix and cells of epiphyseal cartilage, which appears to be related to calcification.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 4 (1969), S. 20-38 
    ISSN: 1432-0827
    Schlagwort(e): Calcification ; Epiphyseal Cartilage ; Bone ; Electrolytes ; Organic matrices
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Un procédé de dissection a été mis au point pour permettre l'analyse zonale du cartilage de l'épiphyse des os de la jambe d'un foetus bovin. Des échantillons de tissu complet et lavé venant des différentes zones ont été analysés pour déterminer leur contenu en électrolyte et en constituants organiques, ainsi que pour leur densité, cendres et humidité. Les résultats ont montré que lorsque la quantité de cendres et la densité augmentaient, l'eau contenu dans le tissu diminuait. Les quantités de cendres dans les zones de cartilage en voie de calcification étaient plus grandes qu'il avait été. Quand elles étaient exprimées comme un pourcentage du poids sec, elles étaient les plus importantes dans le cartilage lavé calcifié que dans le autre zones. Au début de la minéralisation du cartilage, la quantité de Na (m moles/l de tissu frais) diminuait tandis que celles du Ca et du P inorganique augmentaient. Les niveaux de Mg augmentaient pendant que la calcification se poursuivait, mais seulement à une faction du taux du Ca et du P. Les rapports Ca/P inorganique étaient les plus grands dans le cartilage au repos (Cartilage non-différentié hyalin), suggérant un lien initiale entre Ca et les chrondromucoprotéines. Cependant, au début de la calcification, pendant la prolifération du cartilage les rapports Ca/P étaient beaucoup plus petits (ca. 1.50) mais augmentaient graduellement avec l'advancement de la minéralisation. Des changements importants survenaient dans la composition de la phase organique, pendant la calcification endochondrale. Comme il a été déterminé par l'analyse de l'hydroxyproline la quantité de collagéne diminuait progressivement pendant la calcification du cartilage, mais augmentait rapidement pendant la formation d'os. Comme il a été déterminé par l'analyse de l'héxosamine et du sulfute les chrondromucoprotéines étaient aux niveaux les plus éléves pendant la prolifération du cartilage et diminuaient constamment au cours de la calcification. Cependant, bien que la calcification était déja très avancée dans le cartilage hypertrophique, de grandes quantites de mucopolysaccharides étaient encore présentes. Les rapports sulfure/hhéxosamine montraient un léger déclin pendant les premiéres étapes de la calcification, mais augmentaient beaucoup pendant le cours de la minéralisation. Les quantités d'acide sialique étaient plus grandes dans le cartilage de l'épiphyse que dans le cartilage au repos ou dans l'os. Les lipides augmentaient rapidement pendant la calcification du cartilage, mais étaient très réduites dans l'os complètement formé. La signification de ces résultats est discutée.
    Kurzfassung: Zusammenfassung Eine Seziermethode, die eine Schichten-Analyse der Beinepiphysenplatte von Rinderfeten erlaubt, wurde entwickelt. Proben vor und nach Waschen des Gewebes der verschiedenen Schichten werden untersucht in bezug auf Elektrolyte und organische Bestandteile, als auch in bezug auf Dichte, Aschengehalt und Feuchtigkeit. Die Resultate zeigten eine Zunahme des Aschengehaltes und der Dichte, während der Wassergehalt abnahm. Unerwartet hoch waren die Aschenwerte im in Verkalkung begriffenen Knorpel. Ausgedrückt in Prozent Trockengewicht, ergab gewaschener, verkalkter Knorpel den höchsten Wert aller Zonen. In den Frühstadien der Knorpelmineralisation nahm der Natriumgehalt (m Mol/l Frischgewebe) ab, während Ca und anorganischer P zunahmen. Mit fortschreitender Verkalkung erhöhte sich auch der Magnesium-Spiegel, allerdings nur zu einem Bruchteil des Ausmaßes, in welchem Ca und P zunahmen. Die höchsten Ca/P anorg. Verhältnisse wurden im Ruheknorpel (undifferenzierter hyaliner Knorpel) gefunden, was auf eine initiale Bindung von Ca durch Chondromucoproteine hinweist. Die Ca/P-Verhältnisse proliferierenden Knorpels waren jedoch bei Verkalkungsbeginn viel tiefer (ca. 1.50). Diese nahmen allerdings mit fortschreitender Mineralisierung stetig zu. In der endochondralen Verkalkungsphase fanden markante Veränderungen in der Zusammensetzung des organischen Anteils statt. Basierend auf der Hydroxyprolinanalyse nahm der Collagengehalt in der knorpeligen Verkalkungsperiode fortschreitend ab, während er jedoch bei der Knochenbildung rasch zunahm. Die an Hand von Hexosamin- und Schwefelanalysen bestimmten Chondromucoproteingehalte ergaben Höchstwerte im proliferierenden Knorpel und fielen stetig ab mit zunehmender Verkalkung. Trotz der im hypertrophischen Knorpel schon weit fortgeschrittenen Verkalkung waren immer noch große Mengen an Mucopolysacchariden vorhanden. Die Schwefel/Hexosamin-Verhältnisse zeigten eine minimale Abnahme in den frühen Verkalkungsphasen, nahmen jedoch markant zu bei fortschreitender Mineralisation. Der Sialinsäurespiegel war im Epiphysenknorpel, verglichen mit demjenigen des Ruheknorpels oder Knochens, erhöht. In der knorpeligen Verkalkungsphase nahmen die Lipide rasch zu, während jedoch die Werte des vollständig ausgebildeten Knochens stark vermindert waren. Die Bedeutung dieser Ergebnisse wird besprochen.
    Notizen: Abstract A dissection procedure has been devised to permit zonal analysis of the epiphyseal plate of fetal calf leg bones. Samples of whole and washed tissue from the various zones were analyzed for their content of electrolyte and organic constituents, as well as for density, ash and moisture. Results showed that as ash content and density increased, water content decreased. Ash levels in calcifying cartilage zones were unexpectedly high. When expressed as a percentage of dry weight, washed calcified cartilage had the highest content of any zone. In the early stages of the mineralization of cartilage, Na content (mmoles/l of fresh tissue) decreased as Ca and inorganic P increased. Magnesium levels increased as calcification proceeded, but only at a fraction of the rate of Ca and P. Ratios of Ca/inorganic P were highest in resting cartilage (non-differentiated hyaline cartilage), suggesting an initial binding of Ca to chondromucoproteins. However, at the onset of calcification in proliferating cartilage, Ca/P ratios were much lower (ca. 1.50), but gradually increased with advancing mineralization. Marked changes occurred in the composition of the organic phase during endochondral calcification. As determined by hydroxyproline analysis, collagen content progressively decreased during cartilaginous calcification, but increased rapidly during bone formation. As determined by hexosamine and sulfur analysis, chondromucoproteins were at highest levels in proliferating cartilage and decreased steadily as calcification increased. However, although calcification was already well advanced in hypertrophic cartilage, large amounts of mucopolysaccharide still were present. Sulfur/hexosamine ratios showed a slight decline during the early stages of calcification, but increased markedly with further mineralization. Sialic acid levels were elevated in epiphyseal cartilage over those in resting cartilage or bone. Lipids increased rapidly during cartilaginous calcification, but were greatly reduced in fully-formed bone. The significance of these findings is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Coral reefs 17 (1998), S. 37-47 
    ISSN: 1432-0975
    Schlagwort(e): Key words Coral ; Calcification ; Biomineralisation ; Autoradiography ; Freeze-substitution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie
    Notizen: Abstract  The uptake of 45Ca and/or 14C by the skeleton of coral colonies has been commonly used to investigate the processes of calcification. This study reports the differential uptake of these tracers within different regions of the skeleton and tissues of individual corallites and polyps of the hermatypic coral Galaxea fascicularis. Incubation in 45Ca in the light resulted in 80 percent of the 45Ca taken up being deposited in the skeleton. Autoradiography of transverse and longitudinal slices of freeze-substituted polyps and corallites showed that in the light 45Ca was incorporated into the exsert septa, the outside of the thecal walls of the corallite and the inner edges of the septa. Incorporation did not occur in the costae. The radioactivity in the skeleton was considerably greater than in the tissues. In the dark, or in the presence of the photosynthetic inhibitor Diuron, 45Ca was taken up by the exsert septa and was patchily distributed in the corallite walls which suggests that it was not a result of isotopic exchange. The differential incorporation of 45Ca onto the exsert septa was confirmed by scintillation counting. Negligible radioactivity remained in the extrathecal coelenteron after a brief 5 min rinse in non-radioactive seawater. Only 0.1% of 14C taken up in the light was incorporated into the skeleton and this was confirmed by autoradiography. In the presence of Diuron or in the dark, very little 14C was incorporated into tissues or skeleton and in autoradiographs was either not evident in the skeleton or the distribution was similar to that seen in autoradiographs of 45Ca uptake. These results show that the deposition of 45Ca, and therefore calcium carbonate, occurs at specific loci on the skeleton of a corallite. In the dark, deposition occurs specifically at the growing points of the corallite. Differential deposition of calcium carbonate within individual corallites has not been previously reported.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology reporter 17 (1999), S. 323-331 
    ISSN: 1572-9818
    Schlagwort(e): Agrobacterium ; modular vector ; transformation ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Wheat (cv Chinese Spring) tissues were transformed using Agrobacterium tumefasciens and a new plasmid modular vector, pMVTBP. We constructed pMVTBP with unique restriction sites connecting (1) the CaMV 35S promoter, (2) a Kozak sequence, (3) the FLAG epitope, (4) the (His)6 epitope, (5) a coding region (for wheat TATA Binding Protein, wTBP) and (6) the CaMV 35S 3′UTR. This vector thus allows easy exchange of different regulatory or coding sequences. Explants of either germinating mature seeds, or immature embryos, were induced to callus for up to two weeks, treated with virulence-induced bacteria for one hour, then regenerated into plantlets. Transient expression of a GUS reporter gene, assayed at about one week, occurred in 10–12% of calluses. Expression of the FLAG-tagged wTBP was also detected, by immunostaining. Stable expression, by selective growth on geneticin, and by GUS expression at about six weeks, occurred in 1–2% of calluses, quite comparable to that achieved by other methods.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    ISSN: 1573-0832
    Schlagwort(e): deoxynivalenol ; enzyme immunoassay ; feed ; maize ; mycotoxins ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Samples of wheat (n = 25) and maize (n = 30) for animal consumption, collected in 1997 after harvest from western Romania, were analyzed by enzyme immunoassays for mycotoxin contamination. Toxins analyses included deoxynivalenol (DON), 3-acetylDON, 15- acetylDON, fusarenone X (FX), T-2 Toxin (T-2), diacetoxyscirpenol (DAS), zearalenone (ZEA), fumonisin B1 (FB1), aflatoxin B1 (AFB1), ochratoxin A (OA), and citrinin (CT). DON and acetylDONs were the major contaminants in wheat (100%) and maize (46%). Median values for DON, 3-acetylDON, and 15-acetylDON were 880 μg kg-1, 66 μg kg- 1, and 150 μg kg-1 in wheat, and 890 μg kg-1, 180 μg kg-1, and 620 μg kg- 1 in maize, respectively. Additionally, 3,15-diacetylDON was detected in some samples by HPLC-EIA analysis. All samples were negative for FX (〈150 μg kg-1). T-2 was found in wheat (n = 6) and maize (n = 1) at levels between 13 and 63 μg kg- 1. DAS (2.6 μg kg-1) was found in one maize sample. ZEA occurred in all wheat and in four maize samples, median values were 10 μg kg-1 and 250 μg kg-1, respectively. One maize sample contained FB1 (140 μg kg-1). All samples were AFB1-negative (〈4 μg kg-1). OA was found in one wheat sample (37 μg kg- 1), CT was found in one maize sample (580 μg kg- 1). This first reported natural occurrence of a range of mycotoxins in Romanian feeding stuff shows that DON and acetyl DONs may be present at levels which may affect animal production.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    ISSN: 1573-0832
    Schlagwort(e): Fusarium ; mycotoxins ; occurrence ; trichothecenes ; wheat ; zearalenone ; deoxynivalenol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Wheat for human consumption (140 samples) was collected after harvest from all regions of Bulgaria. The 1995 crop year was characterized by heavy rainfall in the spring and summer months. The internal mycoflora of wheat samples was dominated by Fusarium spp. and Alternaria spp., and storage fungi were rarely present. The samples were analysed for contamination with Fusarium mycotoxins deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), T-2 Toxin (T-2), diacetoxyscirpenol (DAS), and zearalenone (ZEA), using enzyme immunoassay methods. DON and ZEA were the predominant toxins, with a contamination frequency of 67% and 69%, respectively. The average levels of these toxins in positive samples were 180 μg/kg (DON) and 17 μg/kg (ZEA), maximum concentrations were 1800 μg kg−1 and 120 μg kg−1, respectively. Acetyl derivatives of DON, namely 3-AcDON and 15-AcDON, were found in 2.1 % and 0.7% of the samples, at at maximum level of about 100 μg kg−1. Only one sample was positive for T-2 (55 μg/kg), DAS was not detected. This is the first report about the natural occurrence of a range of Fusarium mycotoxins in wheat for human consumption in Bulgaria.
    Materialart: Digitale Medien
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  • 14
    ISSN: 1573-0867
    Schlagwort(e): 15N ; non-nod beans ; quantification of N2 fixation ; reference crops ; simulation technique ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A technique for the application of the15N isotope dilution technique for the quantification of plant associated biological nitrogen fixation (BNF) was tested and applied to quantify the BNF contribution to two genotypes ofPhaseolus vulgaris. The technique makes use of sequential measurements of the15N enrichment of soil mineral N, and the uptake of labelled N by the “N2-fixing” plant, to simulate its uptake of soil N (the “soil to plant simulation” technique). The test was made with two non-N2-fixing crops (non-nodulating beans and wheat) and two bean genotypes (PR 923450 and Puebla 152), at two levels of N fertilizer addition (10 and 40 kg N ha−1), to compare the actual N uptake with that simulated from the soil and crop15N data. The simulation of the soil N uptake by the non-nod bean crop using this “soil to plant simulation” technique underestimated by 20 to 30% the true N uptake, suggesting that the mineral N extracted from soil samples taken from the 0–15cm layer had a higher15N enrichment than that N sampled by the roots of this crop. In the case of the wheat crop the simulation resulted in a much greater underestimation of actual N uptake. In general the results using this technique suggested that BNF inputs to the bean cultivars was higher than would be expected from the nodulation and acetylene reduction data, except for the early PR beans in the 40 kg N ha−1 treatment. In this case the total N and simulated soil N accumulation were well matched suggesting no BNF inputs. An allied technique (the “plant to plant simulation technique”) was proposed where the15N enrichrnent of soil mineral N was simulated from the data for total N and labelled N accumulation taken from sequential harvests of either of the non-N2 -fixing control crops. This was then utilized in combination with the labelled N uptake data of the other crop to simulate its soil N uptake. However, the results using either technique indicated that the wheat and non-nod or nodulating beans exploited pools of N in the soil with completely different15N enrichments probably due to differences in exploitation of the soil N with depth.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 45 (1995), S. 209-215 
    ISSN: 1573-0867
    Schlagwort(e): climate ; fertilizer recovery ; 15N fertilizer ; precipitation-evaporation quotient ; soil ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Data was assembled from experiments on the fate of15N-labelled fertilizer applied to wheat (Triticum spp.) grown in different parts of the world. These data were then ranked according to the annual precipitation-evaporation quotient for each experimental location calculated from the average long-term values of precipitation and potential evaporation. Percentage recovery of15N fertilizer in crop and soil varied with location in accordance with the precipitation-evaporation quotient. In humid environments more15N fertilizer was recovered in the crop than in the soil, while in dry environments more15N fertilizer was recovered in the soil than in the crop. Irrespective of climatic differences between locations 20% (on average) of the15N fertilizer applied to wheat crops was unaccounted for at harvest. Most of the15N fertilizer remaining in the soil was found in the 0–30 cm layer. The most likely explanation of these differences is that wheat grown in dry environments has a greater root:shoot ratio than wheat grown in humid environments and, further, that the residue of dryland crops have higher C/N ratios. Both factors could contribute to the greater recovery of15N fertilizer in the soil in dry environments than in humid ones.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 46 (1996), S. 225-234 
    ISSN: 1573-0867
    Schlagwort(e): long-term experiment ; maize ; wheat ; fertilizers ; farm yard manure ; weedicide application ; yield sustainability ; zinc deficiency ; nutrient uptake ; cropping sequence ; organic carbon build-up
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Long-term field experiments play an important role in understanding the complex interactions of plants, soils, climate and management and their effects on sustainable crop production. A long-term fertilizer experiment with maize-wheat-cowpea (fodder) is in progress since 1971 at Punjab Agricultural University farm Ludhiana, India. The experimental result for the first 21 years showed that application of N alone or in combination with P did not produce as much maize and wheat grains as the application of N, P and K together. Eight years after the start of the experiment, the optimal levels of N, P and K application (100% NPK) were unable to sustain the similar (maize) yield level as before because of Zn deficiency. Whereas in FYM amended plots the Zn deficiency did not appear and the higher crop yields could be sustained. The chemical control of weeds could not sustain the maize productivity at the same level as the manual removal of weeds. It was concluded that the high level of crop production can be sustained with the application of N, P and K under intensive cropping system provided deficiency of any of the micronutrient does not crop up. The deficiency of Zn is most likely to occur in semi-arid light textured alluvial soils under intensive cropping without the addition of farm yard manure/organic manures. In maize based cropping systems, manual control of weeds may be preferred to the chemical one. Addition of FYM in conjunction with 100% NPK is most beneficial both from bio-physical and economic point of view.
    Materialart: Digitale Medien
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  • 17
    ISSN: 1573-0867
    Schlagwort(e): millet ; sorghum ; rice ; maize ; wheat ; nutrient harvest index ; post-anthesis nutrient uptake ; recovery fraction ; simulation modelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In land use plans, fertilizer recommendations are indispensable to avoid soil nutrient depletion or soil water pollution. Nutrient relations of five cereals have been evaluated on the basis of a literature review with the aim of arriving at such fertilizer recommendations at regional level. Nutrients considered were nitrogen, phosphorus and potassium for millet, sorghum, maize, rice and wheat. The relevant nutrient relations are fertilizer nutrient application to nutrient uptake, and nutrient uptake to crop yield. In addition, post-anthesis nutrient uptake is considered. Subsequently, obtained results are used in simulation modelling exercises to calculate the time required to attain an equilibrium nutrient balance and to investigate the effect of erosion control and straw recycling. Although fertilizer requirements could be assessed for each of the five cereals, monitoring of nutrient supply from natural sources remains necessary. Moreover, research on fertilizer use should focus on improvement of fertilizer recoveries and multiperiod models for both N and P uptakes by crops to allow quantitative land use planning where the time scale is included.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 44 (1995), S. 217-223 
    ISSN: 1573-0867
    Schlagwort(e): foliar fertilizer ; nitrate ; potassium ; urea ; wheat ; yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Winter wheat crops were grown with ostensibly adequate supplies of all soil nutrients in 1990 and 1991 with the aim of testing if late foliar supplements of K and N, applied at key development stages, could improve grain yield and grain N content. Foliar sprays of KNO3 solution, supplying up to 40 kg K ha−1 in total, at flag leaf unfolded, inflorescence completed and the watery-ripe stage of grain filling, had no effect on yield, yield components or grain N. Urea, supplying 40 kg N ha−1 at flag leaf unfolded, had no effects on grain yield and grain N in 1990, but in 1991 grain N was increased by 0.14% whilst yield was reduced by up to 0.6 t ha−1. Urea scorched flag leaf tips in both years. In 1990, the spring was very dry and foliar supplements might have been expected to have had an effect, but on this highly fertile soil all crop K and N requirements were met from the soil.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 53 (1999), S. 139-146 
    ISSN: 1573-0867
    Schlagwort(e): critical levels of Mn ; soil extractants ; Mn-deficiency ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Seven chemical extractants were tested for their relative performance to predict the response of wheat to Mn application in coarse textured alkaline soils of semi-arid region. Five out of the seven extractants were found to be promising for the estimation of critical level of available Mn in these soils, as the amount of Mn extracted by these extractants was positively and significantly correlated with relative grain yield as well as Mn uptake. The critical deficiency level of soil available Mn with 0.005 M DTPA, 0.02% hydroquinone, 0.02 N sodium pyrophosphate, 0.1N H3PO4 and 0.05N HCl+0.025N H2SO4 was 3.1, 13.8, 23.5, 5.3 and 17.8 mg kg-1 soil, respectively. The 1N ammonium acetate and 0.01M CaCl2 were found to be unsuitable extractants for these soils. Further field trials at eight locations with varying levels of Mn deficiency showed successive increase in the grain yield of wheat with foliar Mn application, emphasizing the need for Mn fertilization when wheat is grown on Mn deficient soils.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 45 (1995), S. 163-167 
    ISSN: 1573-0867
    Schlagwort(e): Basal dressing ; Se-enriched fertilizers ; Se-uptake ; soil texture ; top-dressing ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A multisite field experiment was conducted to study the effect of topdressed Se-enriched Ca(NO3)2 (CN) and basal applied NPK on the selenium (Se) concentration in spring wheat (Triticum aestivum L.). Selenium was applied either through CN (at the rates of 0, 6.45, and 12.91 g Se ha−1) or NPK (5.83 g Se ha−1). Selenium concentration in wheat grains increased consistently with increasing rate of Se-enriched CN or NPK. However, the superiority of Se-enriched CN over NPK in raising the Se concentration in wheat grain depended on location and growth conditions. At the same rate both methods of Se-application were found to be equally effective in raising the Se concentration of wheat grains. The Se concentration of grain was generally higher in the light textured soils than in the medium to heavy textured soils. Without Se application, the Se-concentration in wheat grain was about 16µg kg−1 which is regarded insufficient to meet the Se requirement for Se in animal and human. Calcium nitrate enriched with 25 mg Se kg−1 (6.45 g Se ha−1) increased the Se concentration in wheat grain to a desired level.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    ISSN: 1572-9699
    Schlagwort(e): bioluminescence ; Pseudomonas ; root colonization ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The bioluminescently marked Pseudomonas fluorescens strain 5RL, has been used previously to follow colonisation of soy bean roots (De Weger et al. [1991] Appl. Environ. Microbiol. 57:36-41). In the present paper the method has been further developed and optimized for wheat roots and it is used to get a quick overview of the colonisation patterns of many different root systems at the same time. Colonisation was followed on wheat plants grown in our gnotobiotic sand system (Simons et al., 1996. Mol Plant Microbe Interact 9: 600–607) and the following results were obtained. (i) A spatio-temporal analysis of the colonisation of wheat roots showed that 4 days after planting the highest bacterial activity was observed at the upper part of the root. After 6 days the high bacterial activity at the upper part was further increased, whereas spot-like activities were observed on the lower root parts, possibly due to micro-colonies. (ii) Bacterial mutations causing lack of motility or auxotrophy for amino acids resulted in impaired colonisation of the lower root parts, indicating that motility and prototrophy for the involved amino acid(s) are important factors for wheat root colonisation by strain 5RL. (iii) Coinoculation of strain 5RL with other wild type Pseudomonas strains on the root influenced the colonisation pattern observed for strain 5RL. Colonisation was not visually affected when the competing strain was a poor root coloniser, but was severely reduced when the competing strain was a good root coloniser. The results show that the spatio-temporal colonisation of wheat root by P. fluorescens strain 5RL and derivatives is similar to that of strain WCS365 on tomato. The advantage of the use of lux-marked strains is that the results are obtained much quicker than when conventional methods are used and that the result is supplied as an image of the colonisation pattern of many different roots.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    ISSN: 1572-9761
    Schlagwort(e): Coccinellidae ; Aphididae ; wheat ; spatial scale ; species diversity ; numerical response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influence of prey density, within-field vegetation, and the composition and patchiness of the surrounding landscape on the abundance of insect predators of cereal aphids was studied in wheat fields in eastern South Dakota, USA. Cereal aphids, aphid predators, and within-field vegetation were sampled in 104 fields over a three year period (1988–1990). The composition and patchiness of the landscape surrounding each field were determined from high altitude aerial photographs. Five landscape variables, aggregated at three spatial scales ranging from 2.6 km2 to 581 km2, were measured from aerial photographs. Regression models incorporating within-field and landscape variables accounted for 27–49% of the variance in aphid predator abundance in wheat fields. Aphid predator species richness and species diversity were also related to within-field and landscape variables. Some predators were strongly influenced by variability in the composition and patchiness of the landscape surrounding a field at a particular spatial scale while others responded to variability at all scales. Overall, predator abundance, species richness, and species diversity increased with increasing vegetational diversity in wheat fields and with increasing amounts of non-cultivated lands and increasing patchiness in the surrounding landscape.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 127-143 
    ISSN: 1572-9745
    Schlagwort(e): wheat ; stored-grain ; integrated pest management ; aeration ; biological control ; grain sampling ; insect monitoring ; modeling ; area-wide IPM
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Management of stored-grain insect pests by farmers or elevator managers should be based upon a knowledge of the grain storage environment and the ecology of insect pests. Grain storage facilities and practices, geographical location, government policies, and marketing demands for grain quality are discussed as factors influencing stored-grain insect pest management decisions in the United States. Typical practices include a small number of grain samples designed to provide grain quality information for segregation, blending and marketing. This low sampling rate results in subjective evaluation and inconsistent penalties for insect-related quality factors. Information on the efficacy of insect pest management practices in the United States, mainly for farm-stored wheat, is discussed, and stored-grain integrated pest management (IPM) is compared to field-crop IPM. The transition from traditional stored-grain insect pest control to IPM will require greater emphasis on sampling to estimate insect densities, the development of sound economic thresholds and decision-making strategies, more selective use of pesticides, and greater use of nonchemical methods such as aeration. New developments in insect monitoring, predictive computer models, grain cooling by aeration, biological control, and fumigation are reviewed, their potential for improving insect pest management is discussed, and future research needs are examined.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 3 (1969), S. 151-162 
    ISSN: 1432-0827
    Schlagwort(e): Calcification ; Physiologic ; Phosphonic Acids ; Phosphates ; Crystallization ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé On a étudié la formation de l'hydroxyapatite de calcium cristallin à partir de solutions d'ions de calcium et de phosphate et l'inhibition de la croissance de cristaux de l'hydroxyapatite de calcium au moyen de polyphosphonates et de polyphosphates. Les polyphosphonates, éthane hydroxy-1-diphosphonate-1,1 de disodium et dichlorométhanediphosphonate de disodium, sont inhibiteurs efficaces contre la croissance de cristaux de l'hydroxyapatite de calcium. Les polyphosphates sont aussi inhibiteurs efficaces contre la croissance de cristaux de l'hydroxyapatite de calcium tant que le niveau exigé de polyphosphate intact est présent dans le système. Cependant, à cause de leur instabilité hydrolytique, qui est soulignée par une température élevée, valeur de pH basse, et certaines enzymes, la concentration du polyphosphate diminue avec le tempsin vitro, et son activité comme inhibiteur est perdue. Au contraire aux polyphosphates, les polyphosphonates sont hydrolytiquement stables. Les polyphosphonates sont chimiosorbés sur la surface des microcristallites de l'hydroxyapatite de calcium, ainsi empêchant l'occurrence d'autre croissance de cristaux semblable à l'action d'autres poisons connus de croissance de cristaux. On propose l'extension de cette action sur la formation de l'apatite et cette stabilité des polyphosphonates aux applications médicales et dentaires concernant le metabolisme pathologique de calcium et de phosphate.
    Kurzfassung: Zusammenfassung Die Bildung des kristallinen Calciumhydroxyapatit aus Lösungen, welche Calcium- und Phosphationen enthalten, und die Hemmung der Bildung von kristallinen Calciumhydroxyapatit durch Polyphosphonate und Polyphosphate wurden untersucht. Polyphosphonate, Dinatriumäthan-1-hydroxyl-1,1-diphosphonat und Dinatriumdichloromethandiphosphonate verhindern das Kristallwachstum des Calciumhydroxyapatits. Die Polyphosphate verhindern ebenfalls das Kristallwachstum des Calciumhydroxyapatits, solange die notwendige Konzentration des nicht hydrolysierten Polyphosphats vorhanden ist. Wegen ihrer hydrolytischen Unbeständigkeit, die durch hohe Temperatur, niedrige pH und bestimmte Enzyme erhöht wird, vermindert sich jedoch die Konzentration des Polyphosphats allmählichin vitro, und ihre Hemmungsaktivität geht verloren. Im Gegensatz zu den Polyphosphaten sind die Polyphosphonate hydrolytisch beständig. Die Polyphosphonate werden an der Oberfläche der Mikrokristallite des Calciumhydroxyapatits chemisorbiert und verhindern, wie andere bekannte Kristallwachstumsgifte, auf diese Weise weiteres Kristallwachstum. Die Beständigkeit der Polyphosphonate und ihre Chemisorption an dem Apatit empfehlen ihren Gebrauch in der ärztlichen und zahnärztlichen Praxis, soweit sie den pathologischen Calcium- und Phosphatstoffwechsel betreffen.
    Notizen: Abstract The formation of crystalline calcium hydroxyapatite from solutions of calcium and phosphate ions and the inhibition of calcium hydroxyapatite crystal growth by polyphosphonates and polyphosphates have been studied. The polyphosphonates, disodium ethane-1-hydroxy-1,1-diphosphonate and disodium dichloromethane diphosphonate, are effective inhibitors of calcium hydroxyapatite crystal growth. The polyphosphates are also effective inhibitors of calcium hydroxyapatite crystal growth as long as the required level of intact polyphosphate is present in the system. However, because of their hydrolytic instability, which is enhanced by high temperature, low pH, and certain enzymes, the concentration of the polyphosphate decreases with timein vitro, and its activity as an inhibitor is lost. In contrast to the polyphosphates, the polyphosphonates are hydrolytically stable. The polyphosphonates are chemisorbed on the surface of the microcrystallites of calcium hydroxyapatite and, in the manner of other known crystal growth poisons, thus prevent further crystal growth. The stability of the polyphosphonates and their chemisorption on apatite suggest their use in medical and dental applications involving pathological calcium and phosphate metabolism.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 3 (1969), S. 184-193 
    ISSN: 1432-0827
    Schlagwort(e): Mitochondria ; Calcification ; Calcium ; Chondrocytes ; Growth plate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Des cultures d'épiphyse prélevées sur des rats et des souris ont été étudiées sous le microscope électronique. Un profile de granules mitochondriques de densité électronique a été trouvé. Les chondrocytes dans la zone proliférative avaint peu de granules, alors que ceux des zones successives ont montré une augmentation progressive de leur nombre et densité jusqu'à ce que la zone de calcification provisoire ait été atteinte. Cette zone a montré une distribution périphérique de mitochondries et une réduction du nombre et de la densité des granules mitochondriques. Du calcium isotopique 47 a été utilisé autoradiographiquement pour déterminer la location de calcium dans ces cellules. Des grains ont été trouvés sur les membranes R.E. et sur la plupart des mitochondries. La preuve d'un profile de ces granules et de leur rapport spatial avec la face de minéralisation indique une action éventuelle de mitochondries dès le début de la calcification de la matrice.
    Kurzfassung: Zusammenfassung Epiphysekulturen von Ratten und Mäusen wurden unter dem Elektronenmikroskop untersucht. Ein Profil von mitochondrischen Körnchen mit elektronischer Dichte wurde gefunden. Chondrozyten in der Proliferationszone wiesen wenig Körnchen auf, während die der nachfolgenden Zonen allmählich an Zahl und Dichte zunahmen, bis die Zone der provisorischen Verkalkung erreicht wurde. Diese Zone zeigte eine periphere Verteilung der Mitochondrien und eine Abnahme in Zahl und Dichte der mitochondrischen Körnchen. Isotopes Kalzium 47 wurde autoradiographisch verwendet, um die Lage des Kalziums in diesen Zellen zu bestimmen. Körnchen wurden auf den E.R.-Membranen und auf einem Großteil der Mitochondrien gefunden. Der Nachweis eines Profils dieser Körnchen und ihres räumlichen Verhältnisses zur Mineralisierungsfläche weist auf einen möglich Einfluß der Mitochondrien mit Beginn der Matrixverkalkung hin.
    Notizen: Abstract Rat and mice epiphyseal growth plates were studied with the electron microscope. A gradient of mitochondrial electron-dense granules was found. Chondrocytes in the proliferative zone had few granules, while those of the succeeding zones showed a gradual increase in number and density until the zone of provisional calcification was reached. This zone showed a peripheral distribution of mitochondria and a decrease in the number and density of mitochondrial granules. Isotopic47calcium was used autoradiographically to determine the location of calcium in these cells. Grains were found over the endoplasmic reticulum membranes and over most mitochondria. The demonstration of a gradient of these granules and their spatial relation to the mineralization front suggests a possible involvement of mitochondria in the onset of matrix calcification.
    Materialart: Digitale Medien
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 4 (1969), S. 78-83 
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Calcification ; Osteomalacia ; Phosphorus ; Vitamin D
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Les effects d'une dose de 1 mg de vitamine D3 (40 000 Unités,) administrée par voie intra-veineuse, ont été étudiés sur l'histologie osseuse et le métabolisme du phosphore chez 19 sujets contrôles dont l'histologie était normale et 28 malades présentant les caractères histologiques de l'ostéomalacie par carence vitaminique D. L'administration de la vitamine D n'a entraîné aucune modification histologique ou biologique significative chez les sujets contrôles. Mais chez les ostéomalaciques, il est apparu en moins de sept jours une augmentation très significative du front de calcification à l'interface tissue-ostéoïde-tissue-calcifié. Cette modification s'accompagnait d'une ascension progressive de la phosphatémie et de la réabsorption tubulaire du phosphore atteignant dans le même délai des valeurs normales.
    Kurzfassung: Zusammenfassung Bei 19 Patienten mit normaler Knochenhistologie und bei 28 Patienten mit histologisch gesicherter Osteomalacie wurde die Wirkung von 1 mg Vitamin D3 (40000 Iv) i.v. auf die Knochenhistologie und den Phosphatmetabolismus untersucht. Bei den Kontrollpatienten konnten keine signifikanten Änderungen nach Vitamin D festgestellt werden, wogegen die Osteomalacie-patienten innerhalb von 7 Tagen eine deutliche Zunahme der Verkalkungszone an der Grenze zwischen Osteoid- und Knochengewebe zeigten. Diese Änderung war von einer fortschreitenden Zunahme des Serum-Phosphates, verbunden mit einer gesteigerten renalen tubulären Rückabsorption des Phosphates begleitet; beide kehrten anschließend gleichzeitig wieder zur Norm zurück.
    Notizen: Abstract The effect of a 1 mg dose of intravenous Vitamin D3 (40,000 i.u.) on bone histology and phosphate metabolism was investigated in 19 patients with normal bone histology and 28 patients with histological evidence of osteomalacia. No significant changes occurred in the control patients after Vitamin D but the patients with osteomalacia showed a marked increase, within seven days, in the proportion of osteoid having a calcification front. This was accompanied by a progressive rise in the serum phosphate, which was associated with an increase in the renal tubular reabsorption of phosphate to normal.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 4 (1969), S. 231-244 
    ISSN: 1432-0827
    Schlagwort(e): Calcification ; Pyrophosphate ; Inhibitors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Les propriétés d'induction de calcification des liquides biologiques peuvent être mesurées, in vitro et in vivo, par leur possibilité de redurcir des blocs d'émail décalcifié. Cette propriété est exprimée par les concentrations de calcium (et de phosphate) de solutions synthétiques inductrices de calcification, de concentrations et d'activité connues. Un plasma humain typique a une activité inductrice correspondant à celle d'une solution contenant du calcium, 0,70 mM, Ca/P, 1,67 et fluorure, 0,05 mM. L'activité relativement peu élevée des sérums et des plasmas s'explique par la présence d'inhibiteurs ioniques. L'ion phosphate est l'un d'eux, mais ne peut rendre compte de l'inhibition totale. Des anions et des cations sont responsables de l'inhibition, avec un rôle majeur pour les cations. Les ions suivants, en concentration physiologique, jouent un rôle inhibiteur: P7O 7 4− , HCO 3 − , SiO 4 2− , CrO 4 2− , Mg2+, Zn2+. Un mélange de ces ions provoque une inhibition totale identique à celle du plasma.
    Kurzfassung: Zusammenfassung Der Einfluß biologischer Flüssigkeiten auf den Verkalkungsvorgang kann in vitro und in vivo anhand ihrer Fähigkeit, enthärtete Blöcke von Zahnschmelz wieder zu härten, gemessen werden. Diese Aktivität wird ausgedrückt als Konzentration des Calciums (und Phosphates) synthetischer calcifizierender Lösungen mit bekannter Konzentration und Aktivität. Die Aktivität eines charakteristischen menschlichen Plasmas entsprach derjenigen einer Lösung folgender Zusammensetzung: Calcium 0,70 mM; Ca/P=1,67 und Fluorid 0,05 mM. Die relativ niedrige Aktivität von Serum und Plasma ist bedingt durch das Vorhandensein einer Anzahl ionischer Inhibitoren. Das Pyrophosphation ist ein solcher; er kann aber nicht für die gesamte Inhibition verantwortlich gemacht werden. Sowohl anionische als auch kationische Inhibitoren sind vorhanden, wobei die Kationen den Hauptanteil ausmachen. Folgende Ionen erwiesen sich in einer physiologischen Konzentration als Inhibitoren synthetischer Systeme: P7O 7 3− , HCO 3 − , SiO 4 1− , CrO 4 2− , Mg2+, Zn2+. Zusammengenommen verursachten diese Ionen eine Gesamtinhibition ähnlich derjenigen des Plasmas.
    Notizen: Abstract The calcifying activities of biological fluids can be measured,in vitro andin vivo, by their ability to reharden softened blocks of tooth enamel. The activity is expressed in terms of the calcium (and phosphate) concentrations of synthetic calcifying solutions of known concentration and activity. A typical human plasma had an activity corresponding to that of a solution of the following concentration: calcium, 0.70 mM; Ca/P, 1.67 and fluoride, 0.05 mM. The relatively low activity of serums and plasmas was shown to arise from the presence of a number of ionic inhibitors. Pyrophosphate ion is one such inhibitor but cannot account for the major inhibition. Both anionic and cationic inhibitors were shown to be present, with the cations respresenting the major portion. The following ions at their reported physiological concentration were shown to be inhibitors in synthetic systems: P7O 7 4− , HCO 3 − , SiO 4 2− , CrO 4 2− , Mg2+, Zn2+. In combination, these ions caused a total inhibition similar to those for plasmas.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 3 (1969), S. 266-273 
    ISSN: 1432-0827
    Schlagwort(e): Calcification ; Arteries ; Membranes ; Elastic tissue
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Avec la modification d'une méthode de von Kossa nous avons macroscopiquement representé les dessins de calcification de la membrane élastique intérieure, ainsi que les grosses artères du bassin, des artères des extrémités inferieures, des artères du bras, de la rate et des reins. Dans les artères du type élastique, dans les A.a. ilicae communes et internae, se présentaient les dégénérations calcaires de la membrane élastique intérieure sous forme d'incrustations noires arrondies ou polygonales qui ont été formes en groupes. Elles étaient toujours présentes chez des enfants agés de plus de trois mois et chez des aux adultes. Dans les artères musculaires, se montraient les parties calcifiées de la membrane élastique intérieure en forme de «bandes de calcaire» noires et groupes en paires le long des bordures des fissures de la membrane. Dans le cas où existait une calcinose forcée, on pouvait montrer avec cette méthode tout le système de fissures de la mambrane élastique intérieure. Chez tous les morts âgés de 10 à 20 ans, nous avons trouvé des bandes de calcaire dans les artères musculaires des extrémités inferieures. Ces bandes de calcaire ont été constatées aussi dans des personnes plus âgées. Au point de la fusion des bandes de calcaire et des incrustations calcaire polygonales des dépôts calcaires en forme de feuille («feuilles de calcaire») se forment dans la membrane elastique. Les bandes de calcaire et les feuilles de calcaire représentent des points de cristallisation pour des dépôts calcaire granuleux. Ils se forment dans la plupart des cas sur le la côté externe tourné vers la media.
    Kurzfassung: Zusammenfassung Mit einer modifizierten von Kossa-Methode wurden die Verkalkungsmuster der inneren elastischen Membran der großen Beckenarterien, der Arterien der unteren Extremität, der Oberarm-, Milz-und Nierenarterien makroskopisch dargestellt. In den Arterien vom elastischen Typ, i.e. in den Aa. ilicae communes et internae, erschienen die Verkalkungen der inneren elastischen Membran als schwarze rundliche oder polygonale Inkrustationen, die zu Gruppen angeordnet waren. Sie wurden häufig bereits bei Neugeborenen festgestellt. Bei Kindern, die älter waren als 3 Monate und bei Erwachsenen lagen sie stets vor. — In den muskulären Arterien traten die verkalkten Anteile der inneren elastischen Membran makroskopisch als schwarze paarweise angeordnete „Kalkbänder” entlang den Rändern vorgebildeter Membranspalten auf. Bei ausgeprägter Calcinose konnte mit der angewandten Methode das gesamte Spaltensystem der inneren elastischen Membran dargestellt werden. Kalkbänder wurden in den muskulären Arterien der unteren Extremität bei allen 10–20 Jahre alten Verstorbenen vorgefunden und waren auch in den nachfolgenden Altersstufen stets vorhanden. Beim Zusammenfluß von Kalkbändern und polygonalen Kalkinkrustationen entstehen in der inneren elastischen Membran folienartige Kalkablagerungen („Kalkfolien”). Die Kalkbänder und Kalkfolien stellen Kristallisationspunkte für körnige Kalkablagerungen dar, die zumeist an ihrer äußeren, der Media zugekehrten Seite entstehen.
    Notizen: Abstract Calcification patterns of the internal elastic membrane of the main pelvic arteries, lower limb arteries, brachial, splenic and renal arteries were demonstrated grossly by a modified von Kossa technique. In the elastic segment in the common and internal iliac arteries, the membrane calcification appeared as groups of roundish or polygonal incrustations. They were found frequently in newborns, and were always present in infants of more than three months, as well as in adults. In the muscular arteries, the calcified parts of the internal elastic membrane appeared grossly as pairs of bands (“calcific bands”) along the edges of the pre-existing gaps in this membrane. When calcification was pronounced, the whole pattern of the membrane gaps could be demonstrated by the method used in this study. Calcific bands were found in the muscular arteries of the lower limbs in all 10–20 year-old subjects, and were always present in the older age groups. The confluence of calcific bands or polygonal membrane incrustations found in the iliac arteries lead to sheet-like membrane calcification. The calcific bands and sheets represent crystallizing points for grain-like calcific deposits, which appear later on the medial surface.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 3 (1969), S. 363-365 
    ISSN: 1432-0827
    Schlagwort(e): Calcification ; Mitochondria ; Protozoa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 3 (1969), S. 38-54 
    ISSN: 1432-0827
    Schlagwort(e): Epiphyseal cartilage ; Calcification ; Apatite crystals ; Organic/Inorganic relationships
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Les rapports entre composants organiques et inorganiques du cartilage ont été étudiés au niveau des épiphyses tibiales chez des rats de 5 jours et au niveau des jonctions costo-chondrales chez des cobayes d'un mois. Voici les principaux résultats auxquels on est parvenu: (a) Dans les zones où la calcification s'amorce les cristallites d'apatite sont susceptibles d'être facilement éliminés des coupes en araldite et en glycol methacrylate (GMA) après traitement pendant une heure par une solution d'acide formique au 2%. (b) Les zones décalcifiées sont douées d'une faible densité aux électrons et vont exemptes d'une structure quelconque. Seulement la fixation à l'osmium peut révéler du matériel amorphe. (c) Indépendemment du fixateur et du moyen d'inclusion, les coupes décalcifiées, traitées par l'acétate d'uranyl et/ou par le citrate de plomb, montrent de fines structures allongées dont l'aspect est semblable à celui des cristallites. (d) Ces structures ainsi qu'un fond dense interposé prennent l'acide phosphotungstique (PTA) dans les coupes en GMA, une méthode celle-ci qui met en évidence les polysaccharides. (e) Le fond dense ne prend plus le PTA après traitement par la hyaluronidase et en même temps les structures semblables au cristallites apparaissent plus faibles. Après traitement par l'acétate d'uranyl et le citrate de plomb, l'attaque par la hyaluronidase ne produit aucune modification appréciable. Au contraire l'aspect des structures semblables aux cristallites apparait modifié par la digestion à la papaïne. (f) Quand la décalcification à l'EDTA précéde l'enrobage, des amas de matériel fibrillaire se mettent en évidence dans les zones où la calcification s'était amorcée. L'ensemble de ces résultats permet d'établir la nature organique des structures semblables au cristallites et porte aussi à admettre que celles-ci soient formées par de fins filaments cylindriques (digérés par la papaïne) entourés, et probablement engainés par del polysaccharides (digérés par la hyaluronidase et prennant le PTA dans les coupes en GMA).
    Kurzfassung: Zusammenfassung Die Wechselbeziehungen zwischen den organischen und inorganischen Substanzen des verkalkenden Knorpels wurden in der tibialen und femuralen Epiphyse 5 Tage alter Ratten und in den Rippen 1 Monat alter Meerschweinchen untersucht. Die Hauptergebnisse waren: a) Die Hydroxyapatitkristalle der Frühverkalkungszonen können in Araldit- wie auch in Glycolmethylacrilatschnitten (GMA) mit einer lstündigen Behandlung durch 1% ige Ameisensäure leicht entfernt werden. b) Die entkalkten Zonen haben eine sehr niedrige Elektronendichte und enthalten keine sichtbaren Festkörper. Nach Fixierung mit Osmiumsäure kann man darin ein formloses Material erkennen. c) Eine Färbung der Schnitte mit Uranacetat und Bleicitrat, welche von den Fixier- und Einbettungsmitteln nicht beeinträchtigt wird, zeigt feine, längliche Körper (“Kristallgeister”) an, welche morphologisch den Kristallen von Hydroxyapatit gleichen. d) Die Färbung der GMA-Schnitte mit Phosphowolframsäure (PWS), eine Methode welche Polysaccharide anzeigt, hob diese “Kristallgeister” besonders hervor und demonstrierte auch eine dichte dazwischenliegende Grundsubstanz. e) Diese Substanz ist nach Behandlung mit Hyaluronidase nicht mehr färbbar mit PWS; die Färbbarkeit der “Kristallgeister” wird dabei jedoch nur verringert. Die Hyaluronidasebehandlung verändert die Uranacetat- und Bleicitratfärbung nicht. Die Feinstruktur der “Kristallgeister” wird durch Papainbehandlung sehr angegriffen. f) Falls die Schnitte vor dem Einbetten mit EDTA entkalkt werden, können Faserbündel in den Frühzonen der Verkalkung nachgewiesen werden. Diese Ergebnisse bestätigen die organische Natur der “Kristallgeister”. Sie beweisen auch, daß dieselben aus feinen Proteinstäbchen bestehen (verdaulich in Papain) und von Polysacchariden umgeben und vielleicht auch überzogen sind (verdaulich in Hyaluronidase und anfärbbar mit PWS).
    Notizen: Abstract The organic/inorganic relationships in calcifying cartilage have been studied in tibialfemoral epiphyses of 5-day-old rats and in costochondral junctions of 1-month-old guinea pigs. The main results are: (a) Apatite crystallites in areas of early cartilage calcification are easily removed from araldite and glycol methacrylate (GMA) sections by 1-hour treatment with 2% formic acid. (b) The decalcified areas have a very low electron density and do not contain recognizable structures. Only after osmium fixation can an amorphous material be found in them. (c) Independently from the fixative and the embedding medium, staining decalcified areas with uranyl acetate and/or lead citrate reveals thin, elongated structures (crystallite ghosts) similar in shape to apatite crystallites. (d) These crystallite ghosts and a dense background are stained by phosphotungstic acid (PTA) in GMA sections, a method which reveals polysaccharides. (e) The dense background is no longer stained by PTA after hyaluronidase digestion and the stainability of the crystallite ghosts is reduced. After uranyl acetate/lead citrate staining there are no recognizable changes due to hyaluronidase. But, on the other hand, the fine structure of the crystallite ghosts is modified by papain digestion. (f) Clusters of fibrillar material are present in the areas of early calcification when EDTA decalcification is carried out before embedding the specimens. These results confirm the organic nature of the crystallite ghosts and suggest that they are formed by thin, rod-like protein/like structures (digested by papain) surrounded, and probably sheathed, by acid polysaccharides (digested by hyaluronidase and stained by PTA in GMA sections).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 4 (1969), S. 136-146 
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Calcification ; Osteoblasts ; Osteoclasts ; Poultry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé L'activité des cellules osseuses et la composition du fémur de pondeuses furent examinées pendant sept jours de déficience calcique (diète contenant 0,13% de calcium) et sept jours de réplétion (diète contenant 3,2% de calcium). Du point de vue histologique, seul l'os cortical donnait des signes nets de résorption et d'activité ostéoclastique. Le nombre d'ostéoclastes dans l'os médullaire différait peu des valuers témoin pendant les périodes de déficience et de réplétion subséquente, sauf pour une augmentation significative au premier jour de déplétion. L'effect histologique le plus important dans l'os médullaire était une augmentation marquée en nombre d'ostéoblastes aux troisième, cinquième, et un peu moins au septième jours de déplétion. Le nombre d'ostéoblastes était en corrélation positive avec la teneur de l'os médullaire en ostéoide et négative avec son degré de calcification. L'activité de l'os médullaire en phosphatase alcaline augmentait avec la longueur de la déficience calcique. Un jour après le retour des pondeuses à une diète contenant 3,2% de calcium, la calcification de l'os médullaire avait augmenté de façon significative, le nombre d'ostéoblastes avait diminué au niveau ou au-dessous du niveau de contrôle et l'activité de la phosphatase alcaline avait baissé considérablement. L'importance de ces résultats est discutée par rapport au controle des populations des cellules dan l'os et au rôle de l'os médullaire.
    Kurzfassung: Zusammenfassung Die Zahl der Knochenzellen und die Zusammensetzung des Femurs von Legehennen wurden während einer siebentägigen Calciumentzugsperiode (Calciumgehalt des Futters 0,13%) und einer siebentägigen Ersatzperiode (Calciumgehalt des Futters 3,2%) untersucht. Histologisch zeigte nur die Cortex eindeutige Knochenresorption und osteoklastische Aktivität. Abgesehen von einer signifikanten Zunahme am 1. Tag des Calciumentzuges, variierte die Zahl der Osteoklasten im Markknochen sowohl während der Entzugs- als auch während der nachfolgenden Ersatzperiode wenig. Die wichtigste histologische Änderung im Markknochen bestand in einer starken Zunahme in der Zahl der Osteoblasten am 3., 5. und etwas weniger am 7. Tag der Entzugsperiode. Die Zahl der Osteoblasten zeigte eine positive Korrelation mit dem Osteoidgehalt des Markknochens und eine negative mit dem Grade seiner Verkalkung. Die Aktivität der alkalischen Phosphatase im Markknochen war desto größer je länger den Hennen die calciumarme Ration verfüttert worden war. Die Wiederverabreichung der Ration, welche 3,2% Calcium enthielt, verursachte innerhalb eines Tages eine signifikante Zunahme in der Verkalkung des Markknochens, ein Absinken der Osteoblastzahl auf die Kontrollwerte oder unter sie und eine drastische Verringerung der alkalischen Phosphataseaktivität. Die Bedeutung dieser Ergebnisse in bezug auf die Kontrolle des Knochenzellenbestandes und auf die Funktion des Markknochens wird diskutiert.
    Notizen: Abstract Bone cell activity and the composition of the femur of laying hens were studied during 7 days of calcium depletion on a 0.13% calcium diet and 7 days of calcium repletion on a 3.2% calcium diet. Histologically, only cortical bone showed clear signs of bone resorption and osteoclastic activity during the depletion period. The number of osteoclasts in medullary bone varied little from control values throughout both calcium depletion and repletion, except for a significant increase on the first day of depletion. The major histologicalchange in medullary bone was a marked increase in the number of osteoblasts on the third, fifth and, to a lesser extent, seventh, day of depletion. The number of osteoblasts in medullary bone was positively correlated with its osteoid content and negatively correlated with its degree of calcification. Alkaline phosphatase activity of medullary bone increased with the time the hens had been on the calcium-deficient diet. Returning the hens to the 3.2% calcium ration caused, within one day, a significant increase in medullary bone calcification, a decrease of osteoblast numbers to, or below, control levels, and a drastic reduction in alkaline phosphatase activity of medullary bone. The significance of these findings in relation to the control of bone cell populations and the functions of medullary bone is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 4 (1969), S. 101-112 
    ISSN: 1432-0827
    Schlagwort(e): Calcification ; Ligament ; Mollusc ; Aragonite
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Une étude de microscopie électronique est réalisée sur la formation et la structure du ligament interne deMytilus edulis etPinctada radiata. Cette partie du ligament est dérivée des cellules isthmiques qui sont de forme cylindrique irrégulière. Elles présentent un ergastoplasme bien développé et un appareil de Golgi, engagé dans l'élaboration de vésicules et granules qui s'incorporent au niveau de la conchioline. Les cristaux se forment au niveau du front de calcification, à la surface interne du ligament. Ils sont entourés par une enveloppe. Ils se présentent comme des monocristaux d'aragonite, allongés et en forme d'aiguilles, dispersés dans le ligament. Bien que les constituants de la carapace et du ligament soient identiques, il existe des différences concernant l'augmentation quantitative de conchioline et une diminution en nombre, forme diverse, groupement et croissance des cristaux. Ces différences sont probablement liées à la fonction spécialisée du ligament.
    Kurzfassung: Zusammenfassung Die Bildung und Struktur des inneren Ligamentes vonMytilus edulis undPinctada radiata wurden am Elektronenmikroskop untersucht. Dieser Teil des Ligamentes stammt von den Isthmuszellen ab, deren Form unregelmäßig säulenartig ist. Sie zeigen ein vorspringendes, rauhes endoplasmatisches Reticulum und einen Golgiapparat, welche sich mit der Bildung von Bläschen und Granula befassen, die schließlich in einem integralen Teil des Conchiolins eingebaut werden. Die Kristalle entstehen an der Calcifikationsgrenze an der inneren Oberfläche des Ligamentes und sind in Hüllen eingeschlossen. Sie bestehen aus langen, nadelförmigen, einzelnen Aragonit-Kristallen, die über das ganze Ligament verteilt sind. Obschon die Bestandteile der Muschel und des Ligamentes gleichartig sind, unterscheiden sich die beiden durch eine erhöhte conchiolinmenge, wie auch durch eine Abnahme der Anzahl der Kristalle, welche verschieden in der Form, in der Anordnung und im Wachstum sind. Dies alles ist vermutlich auf die spezielle Funktion des Ligamentes zurückzuführen.
    Notizen: Abstract An electron microscope study was made of the formation and structure of the inner ligament ofMytilus edulis andPinctada radiata. This part of the ligament is derived from the isthmus cells which are irregular columnar in shape. They exhibit a prominent rough endoplasmic reticulum and a Golgi apparatus, which are concerned with the elaboration of vesicles and granules eventually incorporated into an integral part of the conchiolin. The crystals arise at the calcification front at the inner surface of the ligament and are enclosed in envelopes. They consist of long, needle-shaped, single aragonite crystals widely dispersed in the ligament. Although the components of the shell and ligament are similar, differences between them consist of an increased amount of conchiolin, as well as a decrease in the amount, diversity of form, arrangement and growth of the crystals; all probably related to the specialized function of the ligament.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 4 (1969), S. 359-365 
    ISSN: 1432-0827
    Schlagwort(e): Metals ; Ions ; Buffers ; Calcification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé L'action de divers ions métalliques polyvalents sur les propriétés métastables d'un tampon calcifiable a été étudiée. A des concentrations de 1 μM ou moins, les ions Pb2+, F2+, Fe3+, Cr3+, Bi3+ et Al3+ déstabilisent le tampon. Il semble que les phosphates insolubles formés par ces ions déclanchent la précipitation de l'apatite. L'importance de ces résultats dans l'étiologie des calcifications pathologiques et la calciphylaxie est décrite.
    Kurzfassung: Zusammenfassung Die Wirkung von verschiedenen polyvalenten Metallionen auf die Metastabilität eines Calcifikationspuffers wurde untersucht. Bei Konzentrationen von 1 μM oder weniger wird der Puffer durch Pb2+, Fe2+, Fe2+, Cr3+, Bi3+ und Al3+ entstabilisiert. Die Resultate lassen vermuten, daß unlösliche Phosphate, die mit diesen Ionen entstehen, eine Fällung von Apatit veranlassen. Die Bedeutung dieser Befunde bei pathologischen Verkalkungen und Calciphylaxis werden besprochen.
    Notizen: Abstract The effect was studied of various polyvalent metal ions on the metastability of a calcification buffer. At concentration of 1 μM or less, Pb2+, Fe2+, Fe3+, Cr3+, Bi3+ and Al3+ ions were found to destabilize the buffer. The results suggest that insoluble phosphates formed by these ions initiate the precipitation of calcium apatite. The implications of these findings to pathological calcification and calciphylaxis are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 4 (1969), S. 39-47 
    ISSN: 1432-0827
    Schlagwort(e): Dehydroepiandrosterone ; Calcification ; Embryo ; Tissue Culture ; Bone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Les modes d'utilisation de glucose, le contenu de calcium et d'hydroxyproline et la densité cellulaire du perioste de les os frontaux d'embryons de poulet de 12 et 13 jours de developpement, cultivés sur coagulum de plasma, se presentant différenment à chaque âge. Cultivés avec sulfate de déhydroèpiandrostérone en concentration 1 mM, les frontaux de 12 jours montrent un synthese augmentée du matrice osseuse, celle de 13 jours se calcifient à une vélocité significativement plus grande que celle des os contôles. Le degré de calcification au quatrième jour de culture measuré par la relation calcium/hydroxyproline, suit un fonction lineáire avec le logarithme des doses de sulfate de dehydroepiandrostérone employées (0.5, 1,0 et 2,0 mM). Les renseignements obtenus indiquent que les frontaux de 13 jours, cultivés “in vitro” constituent modeles experimentaux appropriés pour étudier l'effet des androgénes sur le tissue osseux.
    Kurzfassung: Zusammenfassung Stirnbeine von Hühnerembryonen an ihrem 12. und 13. Entwicklungstag entnommen und in vitro kultiviert zeigen verschiedene Arten der Glucoseverwertung der Periostzellendichte, des Calcium- und Hydroxyprolingehaltes. Wird Dehydroepiandrosteronsulfat dem Medium in einer 1 mM-Konzentration zugegeben, so beteiligen sich die 12tägigen Stirnbeine vorwiegend an der Knochengewebesynthese, während die 13tägigen signifikant stärker verkalken als die Kontrollen. Gemessen an der Calcium/hydroxyprolin Ratio bildet die Verkalkung der 13tägigen Stirnbeine eine lineare Funktion mit den Logarithmen der verwendeten Dosen von Dehydroepiandrosteronsulfat (0,5, 1,0 und 2,0 mM). Das in vitro kultivierte 13tägige Stirnbein schein ein geeignetes Experimentiermodell zur Studie der Dehydroepiandrosteronsulfatwirkung auf das Knochengewebe zu sein, weil es das grundlegende Phänomen (erhöhte Verkalkung) wiedergibt, welches man auch bei mit Androgenen behandelten Menschen und Tieren beobachtet.
    Notizen: Abstract Chick embryo frontal bones at 12 and 13 days of development cultivatedin vitro exhibit different patterns of glucose utilization, periosteal cellular density and calcium and hydroxyproline content. When dehydroepiandrosterone sulfate is added to the medium at a concentration 1 mM, 12-day frontals engage primarily in osteoid tissue synthesis while 13-day frontals calcify at a significantly greater rate than controls. Measured with the ratio calcium/hydroxyproline, the calcification of 13-day frontals follows a linear function with the logarithm of the doses of dehydroepiandrosterone sulfate employed (0.5, 1.0 and 2.0 mM). The 13-day frontal bone cultivatedin vitro seems to be an adequate experimental model for the study of the effects of dehydroepiandrosterone sulfate on bone tissue because it reproduces the basic phenomenon (increased calcification) observed in man and animals treated with androgens.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 56 (1995), S. 140-144 
    ISSN: 1432-0827
    Schlagwort(e): Bone sialoprotein ; Collagen ; Hole zone ; Calcification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract Bone sialoprotein (BSP) has an affinity to collagen fibrils [25]. A role of carbohydrate chains in the affinity was examined by removing sialic acids of BSP. Neuraminidase treatment of the BSP increased the binding to collagen. Binding sites of BSP on collagen were examined by biochemical and electron-microscopic methods. Purified bovine BSP was labeled with biotin. Collagen α chains or CNBr peptides were separated by electrophoresis and transfered to nitrocellulose membranes. The membranes were incubated with the biotin-labeled BSP, and the bound BSP was visualized with avidin conjugated with alkaline phosphatase. The labeled BSP was preferentially bound to the α 2 chain, and peptides derived from α 2 chain. In another experiment, the labeled BSP was incubated with reconstituted native collagen fibrils. The mixture was put on a copper grid, reacted with avidin conjugated with gold particles, and observed with an electron microscope. The gold particles were seen mainly within hole zones of the fibrils. BSP bound to the α 2 chain within the hole zones may regulate the onset of calcification at hole zones and the cell binding to collagen fibrils.
    Materialart: Digitale Medien
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 2 (1968), S. 1-19 
    ISSN: 1432-0827
    Schlagwort(e): Collagen ; Hydroxyapatite ; Keratin ; Enamel ; Calcification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 2 (1968), S. 60-66 
    ISSN: 1432-0827
    Schlagwort(e): Fluorides ; Topical/Pharmacodynamics ; Penicillin/Pharmacodynamics ; Calcification ; Physiologic/Drug Effects ; Rats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé L'objet de ce travail était de comparer le phénomène de la maturation postéruptive dans les molaires des rats ordinaires et sans germes à qui on a donné à manger un régime «non-cariogène». On a étudié les effets de l'application topique du fluorure et de la nourriture de la penicilline sur la maturation. Les molaires des rats ordinaires (nourris d'un régime «chow» — aliment mixte pour les animaux préparé d'habitude sous la forme d'une farine ou en boulettes) traités topiquement avec une solution à 1% de NaF et les molaires des rats ordinaires nourris d'un régime «chow» complété avec la penicilline à 1% ont montré un degré de maturation significativement plus grand que les molaires des rats de la même portée nourris de «chow» et traités avec de l'eau. De l'autre côté, les molaires des rats sans germes traités topiquement avec une solution à 1% de NaF n'ont montré aucune différence significative dans le degré de maturation des molaires de rats de contrôle semblables traités topiqument avec l'eau. Ces résultats sont en accord avec l'hypothèse que dans un milieu normal le procédé de minéralisation (maturation) est opposé par un procédé de déminéralisation. Le procédé de déminéralisation est un résultat de la production d'acide par des bactéries qui métabolisent les aliments encastrés dans les «sulci» des molaires. On propose que dans les animaux ordinaires le fluorure et la penicilline peuvent influencer la maturation en empêchant le procédé de déminéralisation. Dans les animaux sans germes le procédé de déminéralisation est absent parce que la microflore orale est absente.
    Kurzfassung: Zusammenfassung Der Zweck dieser Arbeit war ein Vergleich des nach dem Durchbruch auftretenden Reifungsphänomens der Backenzähne von gewöhnlich und von keimfrei gehaltenen Ratten, die mit einer nicht-cariogenen Diät ernährt wurden. Es wurden die Auswirkungen von topisch angewendetem Fluorid, verbunden mit Penicillin-Fütterung auf die Reifung untersucht. Die Backenzähne der gewöhnlich gehaltenen Ratten (mit “Chow”-Diät ernährt), die mit einer 1%igen Na-Fluoridlösung topisch behandelt wurden, und solchen deren “Chow”-Diät zu 1% mit Penicillin versetzt wurde, zeigten einen erheblich größeren Reifungsgrad als die Backenzähne von Tieren des gleichen Wurfes, die nur mit der “Chow”-Diät und Wasser ernährt wurden. Diese Resultate stimmen mit der Hypothese überein, daß in einer normalen Umgebung dem Mineralisationsprozeß (Reifung) ein Demineralisationsprozeß entgegenwirkt. Der Demineralisationsprozeß ist durch eine Säureproduktion von Bakterien bedingt, welche die in die Zahnfurchen eingepreßten Nahrungsbestandteile metabolisieren. Es wird die Annahme vorgeschlagen, daß Fluoride und Penicillin bei den gewöhnlich gehaltenen Tieren die Reifung durch eine Inhibition des Demineralisationsprozesses beeinflussen. Bei keimfrei gehaltenen Tieren findet dagegen kein Demineralisationsprozeß statt, da die orale Mikroflora fehlt.
    Notizen: Abstract The purpose of this work was to compare the phenomenon of post-eruptive maturation in molars of conventional and germfree rats fed non-cariogenic diets. The effects of topical application of fluoride and feeding penicillin on maturation were studied. The molars of conventional rats (fed a chow diet) treated topically with a 1% NaF solution and the molars of conventional rats fed a chow diet supplemented with 1% penicillin showed a significantly greater degree of maturation than did the molars of littermate rats fed chow and treated with water. On the other hand, the molars of germfree rats treated topically with a 1% NaF solution showed no significant difference in degree of maturation from the molars of similar control rats topically treated with water. These data are consistent with an hypothesis that in a normal environment the mineralization (maturation) process is opposed by a demineralization process. The demineralization process is a result of production of acid by bacteria metabolizing the diet impacted in the sulci of molars. It is proposed that in conventional animals fluoride and penicillin may influence maturation by inhibiting the demineralization process. In the germfree animals the demineralization process is absent because the oral microflora is absent.
    Materialart: Digitale Medien
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 2 (1968), S. 361-369 
    ISSN: 1432-0827
    Schlagwort(e): Calcification ; Hydroxyapatite ; Keratin ; Hair ; Electron diffraction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Certaines régions du cortex des fibres de kératine contiennent une proportion relativement élevée de matériel non kératinisé. L'orientation microfibrillaire dans ces régions est biaxiale et on y trouve, en outre, des zones de matériel amorphe. Les sels calciques, et en particulier l'hydroxyleapatite, sont étudiés par diffraction électronique qui permet de les localiser et de les identifier. En outre, cette technique permet de déterminer la fréquence de cellules nonkératinisées dans la partie interne du cortex et de les comparer avec les propriétés histochimiques de cette région. Une comparison est effectuée entre la calcification de la kératine et celle intéressant le collagène et l'élastine.
    Kurzfassung: Zusammenfassung Es wird gezeigt, daß Bereiche im Cortex von gewissen Keratinfasern einen relativ hohen Anteil an nichtkeratinösem Material enthalten. Ferner konnte nachgewiesen werden, daß die Orientierung der Mikrofibrillen in diesen Bereichen biaxialer Art ist, und daß Bezirke von amorphem Material vorhanden sind. Die Calciumsalze und insbesondere das Hydroxyapatit konnten mit Hilfe der Elektronendiffraktion lokalisiert und identifiziert werden. Diese Methode hat sich auch als wertvoll erwiesen, um die Wechselbeziehung zwischen dem Vorkommen von einigen nichtkeratinisierten Zellen im Cortexinnern und den histochemischen Eigenschaften dieser Regionen zu zeigen. Ein Vergleich wird gemacht zwischen der Umgebung der Verkalkungsstellen im Keratin mit derjenigen im Kollagen und im Elastin.
    Notizen: Abstract Regions in the cortex of some keratin fibres are shown to contain a relatively high proportion of non-keratinous material. The microfibrillar orientation in these regions is shown to be biaxial in nature and, in addition, areas of amorphous material are reported. Calcium salts, in particular hydroxyapatite, have been located and identified using electron diffraction, which has also proved valuable in correlating the incidence of some non-keratinised cells in the inner part of the cortex with the histochemical properties of this region. A comparison is made between the environment of the sites of calcification in keratin with those in collagen and elastin.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 2 (1968), S. 214-228 
    ISSN: 1432-0827
    Schlagwort(e): Calcinosis ; Calcification ; Cartilage ; Collagen ; Mineral metabolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Les facteurs, influençant la vitesse et l'intensité du phénomène d'association des ions calcium et phosphates avec des fibres contenant du collagène, et préparés à partir du tendon de boeuf par deux méthodes d'extraction différentes, ont été étudiés. Les fibres, obtenues par ces deux méthodes, nécessitent spécifiquement du phosphate pour absorber du calcium et vice versa. L'absorption ionique des deux préparations est inhibée par du Mg++, du pyrophosphate et un peptide acidique, isolé du sérum humain. Alors que les fibres contenant du collagène, préparées selon les deux méthodes, présentent une absorption ionique à des vitesses sensiblement identiques, seule une des méthodes donne une matrice réagissant positivement à la technique de coloration au nitrate d'argent de von Kossa. Etant donné que les deux critères de calcification sont intéressés de façon identique par des conditions de réaction et par des inhibiteurs, il apparait que les deux facteurs sont des manifestations de différents stades de calcification et que des études d'absorption ionique fournissent une base quantitative d'appréciation de la calcification, pouvant être d'importance pour l'étude du mécanisme et de contrôle de la minéralisation tissulaire.
    Kurzfassung: Zusammenfassung Überprüft wurden die Faktoren, welche Geschwindigkeit und Ausmaß der Erscheinung beeinflussen, wobei Calcium- und Phosphationen sich mit den kollagenhaltigen, durch zwei verschiedene Extraktionsmethoden aus Rindersehnen gewonnenen Fasern eng zusammenbinden. Die mit beiden Methoden zubereiteten Fasern benötigen spezifisch Phosphat für die Calciumaufnahme und Calcium für die Phosphataufnahme. Die Ionenaufnahme beider Arten wird durch Mg++, Pyrophosphat und saure, aus dem menschlichen Serum isolierte Peptide gehemmt. Während die nach beiden Methoden präparierten kollagenhaltigen Fasern eine Ionenaufnahme von beinahe gleicher Geschwindigkeit verursachen, ergibt nur eine dieser Methoden eine Matrix, die mit der Silbernitratfärbung nach vonKossa positiv reagiert. Da beide Calcifikationskriterien gleicherweise durch Reaktionsbedingungen und Inhibitoren beeinflußt werden, wird daraus geschlossen, daß beide Erscheinungen verschiedener Stadien des Gesamtcalcifikationsprozesses sind. Untersuchungen über die Ionenaufnahme ergeben eine quantitative Angabe der Verkalkung, welche für die Erforschung des Mechanismus und der Kontrolle der Mineralisation der Gewebe wichtig sein könnte.
    Notizen: Abstract Factors that influence the rate and extent of the phenomenon in which calcium and phosphate ions become firmly associated with collagen-containing fibers prepared from beef tendon by two different extraction methods have been investigated. The fibers produced by both methods specifically require phosphate for calcium uptake and calcium is required for phosphate uptake. Ion uptake by both types is inhibited by Mg++, pyrophosphate, and an acidic peptide isolated from human serum. Whereas the collagen-containing fibers prepared by both methods induce ion uptake at nearly identical rates, only one of the methods produced a matrix that gives a positive response to the silver nitrate staining technique of von Kossa. Since both criteria of calcification are similarly influenced by reaction conditions and inhibitors, it is concluded that both are manifestations of different stages of the overall calcification process and that studies of ion uptake provide a quantitative assessment of calcification which could be of importance for investigating the mechanism and control of tissue mineralization.
    Materialart: Digitale Medien
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 56 (1995), S. 403-407 
    ISSN: 1432-0827
    Schlagwort(e): Bone sialoprotein ; Fibronectin ; Type I colfagen ; MC3T3-E1 cells ; Calcification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract Bone sialoprotein (BSP) containing an Arg-Gly-Asp cell-binding sequence was purified from bovine bone 4 M guanidine-HCl extract after HCl demineralization by a series of chromatographic procedures. When this protein was coated on culture dishes in the presence of type I collagen, it increased both DNA content and alkaline phosphatase (ALP) activity in osteoblast-like MC3T3-E1 cells, and stimulated calcification in the cells, whereas fibronectin, another cell-binding protein, showed a marked increase in the DNA content but had little effect on the ALP activity. These findings suggest that BSP is mitogenic for preosteoblasts and differentiating the cells into osteoblasts, thereby stimulating bone calcification
    Materialart: Digitale Medien
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  • 41
    ISSN: 1573-1561
    Schlagwort(e): Kairomone ; biological control ; cabbage ; wheat ; Diuraphis noxia ; Brevicoryne brassicae ; olfactometer ; infochemical ; preference ; host plants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae) is a parasitoid of several aphid species, including the Russian wheat aphid (RWA),Diuraphis noxia (Mordvilko), and the cabbage aphid (CA).Brevicoryne brassicae (L.). The response of matedD. rapae females to odors from wheat, cabbage, and plant-host complexes was investigated using a four-choice olfactometer. Experienced parasitoids, but not inexperienced females, responded positively to odors of the wheat-RWA complex in a no-choice test. In choice tests, experienced parasitoids did not respond to odors of uninfested cabbage and wheat leaves, but did respond positively to aphid-infested plants and to aphids alone. The response ofD. rapae to the cabbage-CA complex and to CA alone was significantly greater than to the wheat-RWA complex and RWA alone, suggesting an innate odor preference for crucifer-feeding aphids.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 23 (1997), S. 2695-2705 
    ISSN: 1573-1561
    Schlagwort(e): Defense ; herbivory ; aphids ; wheat ; Gramineae ; hydroxamic acids ; Defense theory ; Carbon/Nutrient theory
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Hydroxamic acids (Hx) are natural products of Gramineae that are associated with cereal resistance to pests. We aimed at characterizing the induction of Hx accumulation in seedlings of wheat,Triticum aestivum, by short-term infestation of the cereal aphid,Rhopalosiphum padi. A load of 25 aphids increased significantly the Hx levels in the infested primary leaf in comparison with control levels. Lower loads did not increase Hx concentration. Aphid infestation lasting 16 hr did not elicit induction of Hx, even after a time-lag of 32 hr to allow the expression of any induced response. Forty-eight hours was the minimum duration of aphid infestation required to trigger Hx induction. The age of the infested tissue (the primary leaf) did not affect induction. Similar increases of Hx were found in unfolding, expanding, and totally expanded primary leaves. It was determined that the regime of nutrient supply (N-intensive nutritive solutions at low and high concentration) to wheat seedlings had no effect on the magnitude of the aphid-induced Hx (N-based secondary metabolites). Results obtained are discussed in the framework of general theories of plant defense allocation.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 1311-1316 
    ISSN: 1573-2932
    Schlagwort(e): Pakistan ; air pollution ; ozone ; nitrogen dioxide ; rice ; wheat ; filtration ; yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Open-top chambers ventilated with ambient or chiarcoal-filtered air were used to assess the impact of air pollution on the yield of local cultivars of wheat and rice, at a site on the outskirts of Lahore. At this location, 6-h mean O3 concentrations reach 60 ppb in certain months, and annual mean NO2 concentrations are 20–25 ppb. The experiments showed significant yield reduction in two successive seasons which ranged from 33% to 46% in wheat and from 37% to 51% in rice. The major yield parameter affected was the number of ears or panicles per plant, although there was also evidence of small effects on 1000 grain weight and on the number of grains per ear/panicle. These results have significance in terms of the maintenance of agricultural yields as pollution emissions rise in south and south-east Asia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 1461-1466 
    ISSN: 1573-2932
    Schlagwort(e): ozone ; wheat ; Triticum aestivum ; growth ; senescence ; biomass partitioning ; photosynthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract In closed-chamber fumigation experiments dry matter partitioning and chlorophyll fluorescence of wheat were studied, analysing the effects of ozone during different stages of plant development. Ozone causes enhanced leaf senescence, leading to a loss of green leaf area and, consequently to a decreased supply of assimilates, affecting (in increasing order of severeness) stem, ear and grain productivity because of reduced storage pools for translocation. Leaves of plants before shooting stage were most sensitive but the lack of green leaf area after ear emergence had the most pronounced effects on grain yield. Measurements of photochemical capacity showed that evidence for negative ozone effects could be found in changes of chlorophyll fluorescence parameters in leaf sections not yet showing visible ozone injury. Negative effects on photosynthesis were more distinct with increasing accumulated ozone dose, with increasing age of leaf tissue and with increasing ozone sensitivity of the cultivar. The changes in chlorophyll fluorescence are most likely to be explained by a decreased pool size of plastoquinones caused by ozone.
    Materialart: Digitale Medien
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  • 45
    ISSN: 1573-2932
    Schlagwort(e): Ozone ; wheat ; areal interpolation ; economics ; yield losses ; critical levels
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract In Britain wheat is an important crop accounting for 41% of the total cereal production. In this study ozone concentrations for 1989 estimated as described in Part 1 of the paper are integrated with the estimated wheat distribution to derive a detailed estimate of the impact of ozone on wheat yields at a fine spatial scale (1km × 1km). These data provide estimates for calculating regional and national yield losses. The methodology can be applied to other crop species. Recent research on a range of crops has established relationships between the economic yield loss for certain crops, including wheat, and ozone exposure. Exposure is described as the accumulated exposure above a threshold experienced during the daylight hours (AOT). Critical AOT values are derived from yield exposure relationships which show linear reductions of yield loss with increasing ozone concentrations. This study has made use of land cover data from remotely sensed imagery at 25m resolution and nationally collected agricultural statistics for counties. These data were combined using an areal interpolation technique to provide more spatially articulate estimates of the location and intensity of wheat production. The results demonstrate the economic importance of ozone as a pollutant. Wheat yield losses attributed to ozone vary between different parts of the country but, for years when ozone levels are high, yield losses are likely to be significant in some areas.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 30 (1996), S. 1301-1306 
    ISSN: 1573-5028
    Schlagwort(e): abscisic acid ; glycine-rich ; ribonucleoprotein ; RNA-binding protein ; RNP motif ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A wheat cDNA encoding a glycine-rich RNA-binding protein, whGRP-1, was isolated. WhGRP-1 contains two conserved domains, the RNA-binding motif (RNP motif) combined with a series of glycine-rich imperfect repeats, characteristic of a conserved family of plant RNA-binding proteins. Northern analysis revealed that whGRP-1 mRNA accumulates to high levels in roots and to lower levels in leaves of wheat seedlings. whGRP-1 mRNA accumulation is not enhanced by exogenous abscisic acid in seedlings and accumulates to very high levels during wheat embryo development, showing a pattern different from that of the ABA-inducible wheat Em gene.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 31 (1996), S. 575-584 
    ISSN: 1573-5028
    Schlagwort(e): differential display ; heat shock proteins ; non-coding regions ; PCR ; reverse transcription ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Isolation of cDNAs encoding individual members of a gene family is essential for assessing their role in a biological phenomenon. However, this process is often laborious and slow due to highly conserved protein-coding region that interferes with the isolation of the individual members. Identification of gene-specific probes from 3′ non-coding regions of different members can assist in the fast retrieval and characterization of individual members of a multigene family. We used the recent technique of differential display for the same purpose. As an example of a multigene family in plants, we selected a heat shock protein gene family, HSP16.9 from wheat, with estimated 12 members. We modified the original differential display technique for selective amplification of the 3′ non-coding regions of different wheat HSP16.9 genes by replacing the random 10-mer in the original method with a conserved HSP16.9 gene family-specific primer. Sixteen cDNA fragments from these experiments were sequenced and they represent 8 different members of a 12 member gene family. Our succes can be attributed to shorter 3′ non-coding regions that are typical of higher-plant genes and use of highly conserved gene family-specific primer in these experiments. This modified differential display technique can be of general application to other plant systems where cloning of the different members of a gene family is desired.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 32 (1996), S. 435-445 
    ISSN: 1573-5028
    Schlagwort(e): male sterility ; ovary ; parthenogenetic lines ; pollen allergen ; subtractive hybridization ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To isolate genes specifically expressed at the initiation of plant embryo development we have applied a sensitive subtractive hybridization technique for three isogenic wheat lines of the so-called ‘Salmon system’ with either zygotic or autonomous embryo development. Here we present a gene sequence showing a high homology to grass pollen allergens of type II/III thought to be expressed in pollen tissue only. Surprisingly, the pollen allergen-like sequence, designated Tri a III, is also expressed in gynoecia of the sexual, male fertile wheat line ‘(aestivum)-Salmon’, whereas the two parthenogenetic and male sterile wheat lines ‘(caudata)-Salmon’ and ‘(kotschyi)-Salmon’ completely lack any Tri a III transcript. Our data suggest a positive correlation between the expression of this clone and the manifestation of male fertility. Northern and in situ hybridization analysis revealed that, in addition to its presence in pollen, Tri a III is expressed in the parenchymatous tissue of ‘(aestivum)-Salmon’ ovaries exclusively at the day of anthesis. This precise temporal and spatial expression pattern suggests a more general function of the pollen allergen-like sequence Tri a III not limited to the exhibition of allergens in pollen grains.
    Materialart: Digitale Medien
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  • 49
    ISSN: 1573-5028
    Schlagwort(e): ADP-glucose pyrophosphorylase ; anther ; pollen ; male sterility ; water stress ; wheat ; starch
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In wheat (Triticum aestivum L.), water deficit during meiosis in the microspore mother cells (MMCs) induces pollen abortion, resulting in the failure of fertilization and a reduction in grain set. In stressed plants, meiosis in MMCs proceeds normally but subsequent pollen development is arrested. Unlike normal pollen grains, which accumulate starch during the late maturation phase, stress-affected anthers contain pollen grains with little or no starch. Stress also alters the normal distribution of starch in the anther wall and connective tissue. To determine how starch biosynthesis is regulated within the developing anthers of stressed plants, we studied the expression of ADP-glucose pyrophosphorylase (AGP), which catalyzes the rate limiting step of starch biosynthesis. Two partial-length cDNAs corresponding to the large subunit of AGP were amplified by RT-PCR from anther RNA, and used as probes to monitor AGP expression in developing anthers of normal and water-stressed plants. These clones, WAL1 and WAL2, had identical deduced amino acid sequences and shared 96% sequence identity at the nucleic acid level. In normal anthers, AGP expression was biphasic, indicating that AGP expression is required for starch biosynthesis both during meiosis and later during pollen maturation. AGP expression in stressed anthers was not affected during the first phase of starch accumulation, but was strongly inhibited during the second phase. We conclude from these results that the reduced starch deposition later in the development of stressed pollen could be the result of a lower expression of AGP. However, this inhibition of AGP expression is unlikely to be the primary cause of male sterility because anatomical symptoms of pollen abortion are observed prior to the time when AGP expression is inhibited.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 27 (1995), S. 293-306 
    ISSN: 1573-5028
    Schlagwort(e): ferredoxin ; PetF gene ; circadian rhythm ; light regulation ; wheat ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A genomic clone encoding the precursor of wheat leaf ferredoxin has been isolated and characterised. The uninterrupted PetF gene encodes a polypeptide of 143 amino acid residues, consisting of an N-terminal presequence of 46 amino acid residues and a mature polypeptide of 97 amino acid residues. Southern blot analysis suggests that six copies of the PetF gene are present in the wheat haploid genome. Northern blot analysis has shown that the genes are both developmentally and light regulated in wheat seedlings and provides evidence that a circadian rhythm regulates the steady-state levels of ferredoxin transcripts. The intact wheat gene and several chimeric constructs, containing portions of the 5′-upstream region fused to the β-glucuronidase reporter gene, have been introduced into tobacco plants, but levels of β-glucuronidase activity above background were not detected, suggesting that the 5′-upstream region is unable to function as a promoter in tobacco plants.
    Materialart: Digitale Medien
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  • 51
    ISSN: 1573-5028
    Schlagwort(e): cDNAs ; expression ; mapping porin ; VDAC ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mitochondrial outer membrane of eukaryotic cells contains voltage-dependent anion channels (VDAC) also termed porins. Three cDNAs from wheat (Triticum aestivum) were isolated and sequenced (Tavdac 1–3). They share 65% similarity of their amino acid sequences, and therefore they probably represent isoforms. The deduced amino acid sequence of one of the cDNAs was found to be identical to the purified VDAC protein from wheat mitochondria [8]. Secondary structure analysis of the deduced amino acid sequences of the three vdac cDNAs revealed a characteristic α helix at their N-terminal and β-barrel cylinders characteristic of VDAC channels. The Tavdac cDNAs are differentially expressed in meristematic tissues. The transcript levels of Tavdac 1 in all wheat tissues is at least 2.5-fold higher than Tavdac 2 and Tavdac 3. Tavdac 2 has a low level of expression in all floral tissues whereas Tavdac 3 is highly expressed in anthers. This is the first report on differential expression of vdac genes in plants. The Tavdac genes have been mapped on the wheat genome. Tavdac 1 is located on the long arm of chromosome 5, Tavdac 2 on the long arm of chromosome 1 and Tavdac 3 on the long arm of chromosome 3. A phylogenetic reconstruction indicates that vdac genes underwent numerous duplication events throughout their evolution. All duplications occurred after the separation of plants from animals and fungi, and no orthologous genes are shared among phyla. Within plants, some of the vdac gene duplications probably occurred before the monocotydelon-dicotydelon split.
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  • 52
    ISSN: 1573-5028
    Schlagwort(e): cDNA ; expression ; FKBP ; PPIase ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A novel cDNA encoding for a peptidyl-prolyl-cis-trans-isomerase (PPIase) belonging to the FK506-binding protein (FKBP) family was isolated from wheat. It contains an open reading frame of 559 amino acids and it represents the first plant FKBP-PPIase to be cloned. It possesses a unique sequence which is composed of three FKPB-like domains, in addition to a putative tetratricopeptide repeat (TPR) motif and a calmodulin-binding site. The recombinant FKBP-PPIase expressed in and purified from Escherichia coli exhibits PPIase activity that is efficiently inhibited by the immunosuppressive drugs FK506 and rapamycin. Northern blot analysis showed that wheat FKBP was found mainly in young tissues. Polyclonal antibodies revealed the presence of cross-reacting proteins in embryos, roots and shoots. The unique structural features, the enzymatic activity and the presence of putative isoforms in wheat tissues indicate the possibility of the involvement of wheat PPIase in essential biological functions, similar to other members of the FKBP gene family.
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  • 53
    ISSN: 1573-5028
    Schlagwort(e): chloroplast ; in vitro transcription ; light ; psbA ; psbD/C operon ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Dynamical aspects of three chloroplast promoters responding to change in light condition were examined in mature chloroplasts of wheat (Triticum aestivum) by in vitro transcription. The wheat psbD/C operon has four distinct promoters, two of which named as D/C-3 and D/C-4 promoters dominantly function in mature chloroplasts to produce the mRNAs encoding D2/CP43 and CP43 alone, respectively. Activity of the D/C-3 promoter in mature chloroplasts was reduced to less than 30% by 24 h dark adaptation and recovered by re-illumination to the original level within 30 to 60 min. The activation of the D/C-3 promoter which requires de novo cytoplasmic protein synthesis was induced by low fluence of light (e.g. 16 µE m-2 s-1), but the extent of activation increased with increasing light fluence. The accumulation of mRNAs from the D/C-3 promoter saturated at 2- to 3-fold higher level within 2 h when the dark-adapted seedlings were transferred to the lig at 72 µE m-2 s-1, concomitant with the increase in rate of D2 synthesis, suggesting that synthesis of D2 in mature chloroplasts is controlled via the D/C-3 promoter activity in a light-dependent way. Activity of the D/C-4 promoter slightly increased in the dark and decreased in the light. Effect of light on the psbA promoter activity was not observed at all in mature chloroplasts. In vitro transcriptional analysis of the D/C-3 promoter with 5′ deletion mutations revealed that at least two cis elements which are located within the sequences of -78 to -47 and -46 to -29 of the transcription initiation site, respectively, act as enhancing elements in the D/C-3 promoter. The light-switching element of the transcription, however, was suggested to be located in the core promoter sequence downstream of the -35 element.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 33 (1997), S. 935-941 
    ISSN: 1573-5028
    Schlagwort(e): cold temperature ; dehydration ; greening ; protein kinase ; Triticum aestivum/ ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have identified a new wheat PKABA1/-like protein kinase gene, TaPK3/, that is expressed in greening wheat seedlings. TaPK3 has high sequence homology (97% similarity with some sequence diversity at the 3' end) to the wheat PKABA1 protein kinase mRNA, which is upregulated by cold-temperature treatment, dehydration and abscisic acid (ABA). Use of a TaPK3 gene-specific probe has revealed that TaPK3 is differentially expressed with respect to PKABA1. TaPK3 mRNA accumulates in greening shoot tissue of wheat, but is not affected by dehydration, cold-temperature treatment or ABA. Based on sequence and expression differences, we conclude that expression of the PKABA1/-like protein kinases is not limited to stress responses.
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 34 (1997), S. 643-650 
    ISSN: 1573-5028
    Schlagwort(e): callus ; crown tissue ; gene expression ; low temperature ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The low-temperature (2 °C)-specific wheat cDNA, pTACR7, represents a gene designated tacr7 from hard red winter wheat (HRWW; Triticum aestivum L. cv. Winoka). The term low-temperature-specific (LTS) is used because tacr7 is not induced by ABA or stresses such as salt, dehydration, and heat. pTACR7 was isolated by RT-PCR with mRNA from wheat crown tissue, the oligonucleotide primers derived from the barley cognate pHVCR8 (GenBank accession number L28091). Based on the deduced amino acid sequence, TACR7 is highly hydrophobic, with a single transmembrane domain and an amino acid bias for leucine (19%). Thus, the encoded protein TACR7 is unique among low-temperature-regulated wheat proteins described in the literature. Analysis of steady-state levels of tacr7 transcripts (630 nt) showed accumulation in wheat seedlings, crown tissue, and callus cultures after transfer from control (25 °C) to low temperature (2 °C). No detectable transcripts were observed by northern blot hybridization with pTACR7 probe from seedling or callus treated with ABA, salt, dehydration, or heat stress. tacr7 transcripts accumulated during 2 °C exposure to a greater amount in a freeze-resistant HRWW (FR; SDmut 16029) than in a freeze-susceptible HRWW (FS; SDmut 16169) crown tissue, with the largest difference between genotypes being 30% ± 3% at 3 weeks.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell reports 16 (1996), S. 12-17 
    ISSN: 1432-203X
    Schlagwort(e): Triticum aestivum L. ; wheat ; transformation ; biolistics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have developed a method for the accelerated production of fertile transgenic wheat (Triticum aestivum L.) that yields rooted plants ready for transfer to soil in 8–9 weeks (56–66 days) after the initiation of cultures. This was made possible by improvements in the procedures used for culture, bombardment, and selection. Cultured immature embryos were given a 4–6 h pre-and 16 h post-bombardment osmotic treatment. The most consistent and satisfactory results were obtained with 30 μg of gold particles/bombardment. No clear correlation was found between the frequencies of transient expression and stable transformation. The highest rates of regeneration and transformation were obtained when callus formation after bombardment was limited to two weeks in the dark, with or without selection, followed by selection during regeneration under light. Selection with bialaphos, and not phosphinothricin, yielded more vigorously growing transformed plantlets. The elongation of dark green plantlets in the presence of 4–5 mg/l bialaphos was found to be reliable for identifying transformed plants. Eighty independent transgenic wheat lines were produced in this study. Under optimum conditions, 32 transformed wheat plants were obtained from 2100 immature embryos in 56–66 days, making it possible to obtain R3 homozygous plants in less than a year.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 99-101 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; High temperature open-tubular columns ; Solvent make-up ; Acetophenone oxidation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Acetophnone, a substance stable at room temperature, is readily oxidizes in a high temperature open tubular liquid chromatographic system by the residual oxygen in the mobile phase. The oxidation product is less UV absorptive and detection sensitivity decreases greatly. To prevent the oxidation, through degassing of the mobile phase is necessary.
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  • 58
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Endotoxins ; Lipopolysaccharide ; Aminated poly(γ-methyl L-glutamate) ; Bovine serum albumin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A method is described for the selective removal of endotoxins from various protein solutions using columns packed with aminated poly (γ-methyl L-glutamate) (PMLG-NH2) spheres. The PMLG-NH2 adsorbents showed a high adsorbing activity for endotoxins which had an ionic strength of μ=0.05–1.0 and pH 5.0–9.0. The endotoxin-adsorbing capacity per millitre of the wet adsorbent increased from 0.40 to 1.35 mg (E. coli O111: B4 LPS) at μ=0.2 and pH 7.0 while the aminogroup content of the adsorbent increased from 0.8 to 3.5 meq g−1. The PMLG-NH2-3.5 has an amino-group content of 3.5 meq g−1. This column packing selectively adsorbed endotoxins, without loss of the protein, from a γ-globulin or cytochromec solution which contained endotoxins at μ=0.05 and pH 7.0. On the other hand, when bovine serum albumin (BSA) was present in solution with endotoxins, both the endotoxins and the BSA were adsorbed by the column. The BSA-adsorbing activity increased with increasing amino-group content of the adsorbent. However, this undesirable adsorption was suppressed with increasing ionic strength of the buffer. As a result, when the packing which had an amino-group content of 1.5 meg g−1 was used in conditions of μ=0.2 and pH 7.0, the endotoxins were removed from a BSA-containing solution without affecting the recovery of the BSA.
    Materialart: Digitale Medien
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 51-57 
    ISSN: 1612-1112
    Schlagwort(e): Column electrophoresis ; Column liquid chromatography ; Phenolic lignin degradation compounds ; Sugar degradation products ; Quantitative analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A method for the quantitative analysis of phenolic lignin degradation products by capillary electrophoresis (CE) with on-column UV detection has been developed. The liquid biomass solutions contain low molecular hemicellulosic sugars and phenolic lignin degradation products with various degrees of polymerization. Special attention has been paid to the monomeric phenolic components of lignin degradation fragments, e.g. derivatives of phenolic acids, aldehydes, and alcohols. Uncoated fused silica capillaries and borate-phosphate buffer systems at moderate pH conditions were used in order to separate the compounds of interest. To provide validation of the method, the same samples were analyzed independently by HPLC using gradient elution on a RP-C18 column. As sugar degradation fragment, furan-2-carboxylic acid was detected.
    Materialart: Digitale Medien
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 85-90 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Phenolic compounds ; Ion-pair solid phase extraction ; On-line trace enrichment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Two packing materials, C18 and PLRP-S, are studied for on-line trace enrichment of phenolic compounds in water. Various precolumns of different internal diameter are also tested and the addition of an ion-pair reagent to increase retention and thus, breakthrough volumes of phenolic compounds, is studied. Best results are obtained when a PLRP-S precolumn is coupled on-line with a C18 analytical column and DAD detector. Addition of TBA considerably increases breakthrough volumes. In contrast, when a C18 precolumn is used, breakthrough volumes are lower and it is impossible to determine TCP and PCP, under the experimental conditions used, because of interference of other nonpolar compounds in the samples. The performance of the system is evaluated with river and tap water and the preconcentration of 10 ml of sample in a PLRP-S precolumn involves a linear range between 1 μg 1−1 and 20 μl−1 and limits of determination between 0.5 μg l−1 and 1 μg l−1 are obtained.
    Materialart: Digitale Medien
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 631-637 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Trace analysis ; Pesticides in tap water ; Aromatic sulphonates
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Methodology and instrumentation are described which allow chromatographic screening of water samples under substantially simplified conditions and at reduced cost. A single column is used to accomplish sample extraction, trace enrichment, and separation. The performance of such a system is demonstrated, and the results compared with conventionally used concepts.
    Materialart: Digitale Medien
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 669-673 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Transchelation ; Zinc pyrithione and related compounds ; Antidandruff formulations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary An analytical procedure has been developed for the determination of zinc pyrithione in antidandruff formulations. Zinc pyrithione was converted into a stable copper complex and then analysed by reversed-phase HPLC. The proposed method allows the separation of the analyte from related pyrithiones and therefore is able to verify the compliance of cosmetic preparations with current legislation.
    Materialart: Digitale Medien
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  • 63
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Benzodiazepines ; Solvent effects ; ACN clusters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Two different methods were used to determine the separation factor α at different temperatures and the Gibbs-Helmholtz parameters (Δ(ΔH), Δ(ΔS)) of two adjacent benzodiazepines on a chromatogram were obtained from plots of lnα versus 1/T. We first studied each factor (fraction of water ϕ in the ACN/water mixture and column temperatureT), which controls the retention mechanism, and then we examined the simultaneous variation of all these factors. The changes in Δ(ΔH) and Δ(ΔS) in relation to a volume fraction of water ϕ in an ACN/water mixture were examined. In the ACN/water system, Δ(ΔH) was fairly constant in the acetonitrile region of ϕ≤0.52 and appears to be a roughly linear function of ϕ for ϕ≥0.52. In this system Δ(ΔS) is approximately a parabolic function of ϕ with an optimum at ϕ≅0.52. The retention mechanism of ten benzodiazepines was found to be significantly different in the methanol/water and ACN/water mixtures. The separation optimization of these ten benzodiazepines was then considered. A fraction of water of 0.43 in the ACN/water mixture and a column temperature of 44°C gave the most efficient separation conditions in the ACN/water mixture.
    Materialart: Digitale Medien
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  • 64
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Polyurethane degradation products ; 2,4- and 2,6-toluendiamine ; Urine analysis ; Breast implants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A reversed-phase HPLC method has been developed for the urinary determination of mutagenic 2,4- and 2,6-toluendiamines. These amines are degradation products of polyurethane, a material used to cover textured silicone breast implants. FMOC-Cl was used as fluorescent derivatising agent in order to obtain a limit of detection of 15 ng/ml in urine. Pre-treatment of urine samples was by liquid/liquid extraction and urine specimens of patients after surgury were analysed.
    Materialart: Digitale Medien
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 41 (1995), S. 657-660 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Polyphenols ; Flavonoids ; Phenolic acids and aldehydes ; Eucalyptus spp.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Standards of the polyphenols occurring in wood, bark and leaf extracts ofEucalyptus spp. (i.e. flavonoids and phenolic acids and aldehydes) have been analyzed by HPLC using reversed phase columns, gradient elution and diode-array detection. The conditions used are reported.
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 657-661 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Reversed phases ; Polyencapsulated silica ; Polyacrylates
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary By copolymerization of silica modified with vinyl groups and acrylic acid esters in suspension highly efficient, polymeric-encapsulated stationary-phases can be prepared. The suspending liquid has to be selected such that the monomers are at least partially adsorbed on the surface and the polymer formed does not precipitate. Under these conditions stationary phases capable of speedy mass transfer can be prepared, where the reduced plate heights are between 2 and 3. The silica surface shielding is optimized so that basic and acidic solutes elute with symmetrical peak.
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  • 67
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Chiral resolution of amino acids ; Pre-column derivatization ; Fluorescent chiral tagging reagents ; Stereochemical purity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Derivatization of amino acid enantiomers with fluorescent chiral Edman-type reagents, 4-(3-isothiocyanatopyrrolidin-1-yl)-7-nitro-2,1,3-benzoxadiazole [R(−)- and S(+)-NBD-PyNCS] and 4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole [R(−)-and S(+)-DBD-PyNCS], yields corresponding diastereomers separable by reversed-phase HPLC on normal achiral columns. The resolved diastereomers were detected fluorometrically at 530 nm with excitation at 490 nm for the NBD-PyNCS derivatives and at 560 nm with excitation at 450 nm for those derived from DBD-PyNCS reagents. This HPLC-derivatization method was used for evaluation of stereochemical purity for some synthetic commercial peptides. The enantioanalysis was reliable down to 0.05% racemization of the amino acid residues and a quantity of 100 μg peptide sample was usually enough for the analysis. Two acid hydrolysis methods, i.e. the standard procedure with constant-boiling hydrochloric acid (HCl) and a rapid vapor-phase procedure with HCl-trifluoroacetic acid (TFA) mixture, were compared. The later was found to be unsuitable owing to increased racemization of the amino acid residues during the hydrolysis. Judging from the results obtained for proline and leucine residues, most of the tested peptides including biologically active peptides, such as neurotensin, [d-Ala2,d-Leu5]-enkepharin and morphine tolerance peptide, possessed stereochemical purities higher than 98%. Influence of structural features of the peptides on the racemization of the amino acid residues was found to be significant.
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  • 68
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Mass spectrometric detection ; Fast atom bombardment ionization ; Serum bile acid ; Rat bile
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary In order to analyse bile acids in biological matrices, e.g. rat bile and human serum, high performance liquid chromatography (HPLC) was coupled to continuous-flow fast atom bombardment mass spectrometry (CFFAB-MS). A gradient elution system which had already proved to be well suited for the quantitative determination of conjugated bile acids in bile was modified to allow HPLC-CFFAB-MS-coupling. Due to the sensitivity of this coupling method it is possible to obtain more information about the biliary bile acid pattern and species-specific secondary bile acids. Furthermore, we were able to identify obviously unknown bile acid species in rat bile which most likely classify as mono-oxo and di-oxo-taurocholates (MW 513 Da, 511 Da) and mono-oxo-glycocholates (MW 463 Da). In the present study we show that using this system it is possible to determine both conjugated and unconjugated as well as sulfated bile acids, without time consuming group separation and derivatization, from rat bile and human serum. In addition, it is suggested that the method presented here should be considered for use in routine analysis.
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  • 69
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Fluorescence enhancement ; Bovine serum albumin ; Dansylamino acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The effects of acetonitrile and bovine serum albumin (BSA) concentrations on the signal intensity and retention behavior of dansylamino acids have been examined by using γ-cyclodextrin-bonded silica gel as the stationary phase in microcolumn liquid chromatography. Fluorescence intensities of dansylamino acids were enhanced by BSA as a mobile phase additive, e.g., detection limits of dansyl derivatives of L-Ala and L-Phe were improved by a factor of 12–18.
    Materialart: Digitale Medien
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  • 70
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Micellar liquid phases ; Octanol-water partition coefficient ; Benzene and naphthalene derivatives
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary It is shown that the logarithm of the capacity factor (log k′) for fifteen benzene and naphthalene derivatives in micellar liquid chromatography with forty nine different mobile phases generally correlates better with the logarithm of the octanol-water partition coefficient (log Pow) than the capacity factor (k′). Optimum conditions are established to obtain the best linear correlations of log k′-log Pow.
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 247-252 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Photolysis ; Electrochemical detection ; Drugs with chlorinated aromatic rings
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Pharmaceuticals containing a thiazide ring or chlorinated aromatic ring were investigated with respect to enhanced selectivity in determination. Oxidative electrochemical detection coupled with HPLC was used to study the influence of the pH of the mobile phase under conditions of photolysis. To cover a pH range 3.9–12, the employment of a polymer column stable in alkaline media was necessary. The method offers the great advantage of derivatization without chemicals at low operating potentials, thereby providing high selectivity.
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 296-302 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Structural isomer separation ; Cyclodextrin ; Polymers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Several β-cyclodextrin (CD)-bonded stationary phases for high performance liquid chromatography (HPLC) were prepared, based on silica beads coated with a poly(alkylamine), [poly(ethyleneimine)(PEI)]. In order to obtain stationary phases with a high content of CD and maximum accessibility of the CD cavity, the functionalization was carried out after the coating, using the mono-tosyl derivative of CD as the intermediate. The ability of these supports to separate ortho, meta and para isomers of some disubstituted benzene derivatives was examined. The contribution of the amino groups of the polymer and of the CD cavity to the separation process is discussed. The resolution is mainly based on the difference in the stability of the complexes of the various isomers with CD. The influence of the amount of CD on the height of the theoretical plate is also studied.
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  • 73
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Reversed phase ; Polystyrene ; Pellicular ; Ultra high molecular mass
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Ultra high molecular mass (〉 7 million dalton) polystyrenes are prone to degradation in size exclusion chromatography. In gradient elution reversed phase HPLC they do not elute visibly on small particle size porous supports. However, large diameter C18 pellicular particles were successfully employed for reversed phase study of ultra high molecular mass (15 million dalton) polystyrenes without polymer degradation during elution. Although retention for the lower molecular mass polystyrenes was lower than on small diameter porous particles, the medium high molecular mass polystyrenes (0.5–1 million dalton) showed similar retention. The addition of small diameter porous particles in small quantities, to the large diameter pellicular particles, increased the amount of retention of the low molecular mass polystyrenes without affecting the higher molecular mass polystyrenes.
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  • 74
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Methyl ethyl ketone in urine ; Derivatization ; 3-Methyl-2-benzothiazolinone hydrazone ; Comparison with GC-MS
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A HPLC method for the determination of methyl ethyl ketone (MEK) in urine after derivatization with 3-methyl-2-benzothiazolinone hydrazone is proposed. The calibration curve for the ketone was linear, ranging between 0.23–10 mg/L, with a detection limit of 0.025 mg/L. The results were compared to those obtained by GC-MS, coupled to the headspace technique. MEK derivatization and the derivative purification processes were verified with respect to the main variables such as reaction temperature, reagent concentration, probable interferences and enrichment phase. The method is simple and reliable and shows a good sensitivity.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 382-386 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Sulfonamides in foodstuffs ; Honey ; Milk ; Eggs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A procedure for the simultaneous determination of several sulfonamides in different foods, such as honey, milk and eggs is proposed. The analysis is carried out using reversed phase liquid chromatography with spectrophotometric detection. Optimization of the mobile phase led to good separation and a short analysis time when an initial isocratic step with a 3∶97 acetonitrile: water mixture was used for 5 minutes, followed by a linear gradient up to a 40∶60 mixture over 15 min. The proposed method is suitable for routine quality control analysis to ensure the absence of sulfonamides in foods. Recovery studies yielded good results for all food samples because there were no interferences from the matrices.
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 40 (1995), S. 411-416 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Particle beam LC/MS interface ; Capillary columns for LC ; Mycotoxins ; Peanut meal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new method for the analysis of aflatoxins in food extracts, based on liquid chromatography/mass spectrometry interfacing, is presented. The chromatographic separation was performed with a reversed phase packed capillary column coupled with a modified particle beam interface capable of handling microliter per minute flow rates. This system allows higher overall sensitivity and easier operation procedures. The method has proved to be particularly suitable for the analysis of the toxins in very complex matrices. The specificity of electron impact ionization allowed positive identification of the aflatoxins with an excellent response linearity for accurate quantitation.
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  • 77
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Thin-layer chromatography ; Reversed phase ; 2-benzoylbenzoic acids ; Anionic and cationic counter ions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The 2-benzoylbenzoic acid series was investigated by reversed-phase, high-performance, thin-layer and column chromatography using various alkylammonium salts and di(2-ethylhexyl)orthophosphoric acid as polar associating reagents. The effects of the individual substituents on retention were quantified by Δlog k′ and ΔRM values. The compounds investigated differing in molecular structure (hydrophilic and hydrophobic substituents) commonly occurring groups in drugs and biologically active substances provide information on molecular interaction in these ion-pair systems. The combined effects on retention of organic modifier and ion-pair reagent concentration were investigated.
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  • 78
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Two-dimensional separation ; D- and L-amino acids ; Enantioseperation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A two-dimensional, column liquid chromatographic system is used for the determination of the D- and L-enantiomers of amino acids in biological samples. Separation of the amino acids is first on ion-exchange column by gradient elution with a sodium citratesodium chloride buffer. Enantioseparation is by subsequent injection of 3 μl heart-cuts of the individual amino acids onto a second column with a chiral crown ether stationary phase. Finally, fluorescence detection is after post-column labelling of the amino acids using ano-phthalaldehyde-2-mercaptoethanol reagent solution. The high separation power and selectivity of the system allow processing of complex samples with hardly any additional treatment and the determination of small quantities of D-amino acids in the presence of excess L-form. Applicability of the system is illustrated by the determination of D- and L-aspartate, serine, glutamate and alanine in various complex biological samples, such as protein hydrolysates, urine and biotechnological and food samples. Data are given on detectability, repeatability and linearity.
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 41 (1995), S. 43-50 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Ion pair LC ; Sweeteners, preservatives and antioxidants ; Food additive analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A paired-ion, reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of sweeteners (dulcin, saccharin-Na and acesulfame-K), preservatives (sodium dehydroacetate, sorbic acid, salicyclic acid, benzoic acid, succinic acid, methyl-para-hydroxybenzoic acid, ethylpara-hydroxybenzoic acid, n-propyl-para-hydroxybenzoic acid, isopropyl-para-hydroxybenzoic acid, n-butyl-para-hydroxybenzoic acid, and isobutyl-para-hydroxybenzoic acid), and antioxidants (3-tertiary-butyl-4-hydroxyanisole and tertiary-butyl-hydroquinone). A mobile phase of acetonitrile-50 mM aqueous α-hydroxy-isobutyric acid solution (pH 4.5) (2.2 ∶ 3.4 or 2.4 ∶ 3.6, v/v) containing 2.5 mM hexadecyltrimethylammonium bromide and a C18 column with a flow rate at 1.0 mL/min and detection at 233 nm were used. This method was found to be very reproducible with detection limits ranged from 0.15 to 3.00 μg. The retention factor (k) of each additive could be affected by concentrations of hexadecyltrimethylammonium bromide and α-hydroxyisobutyric acid, and pH and ratio of mobile phase. The presence of additives in some food samples was determined.
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  • 80
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Limit of detection ; Precision ; Uncertainty prediction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The precision of integration over noisy instrumental output for quantitative analysis is studied. A probability theory is developed to predict the relative standard deviation (RSD) of integration results over an integration domain from one-point integation (peak height measurement) to entire area integration in HPLC. Common integration modes of horizontal zero line and oblique zero line are taken into account, but no peak overlap is assumed. The question of the analytical superiority of peak height measurement or integration for quantitation is answered. In the HPLC apparatus used, the minimum RSD of measurements is found in the integration domain of ca. ±0.5 σ for analytes [peaks are approximated by the Gaussian signal of width, σ (standard deviation)]. The RSD of integration measurements is also shown to depend on the stochastic properties of back-ground noise (uncorrelated noise and correlated 1/f type noise). The theoretical conclusion is verified by Monte Carlo simulation and HPLC experiments for some aromatic compounds.
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  • 81
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Ion-pair and GPC separations ; Amoxicillin oligomers ; β-Lactam ring polymers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Polymeric substances formed from concentrated sodium amoxicillin in an aqueous solution have been separated using two high-performance liquid chromatographic methods. We used a C18 reversed-phase column with tetrabutylammonium chloride as an ion-pairing agent with an acetonitrile gradient and a TSKgel G2500PWxl column with water as the solvent for gel permeation chromatography. The separated materials, ranging in size from the monomer to the tetramer, have been characterized by functional-group chemical analysis, while the identification of the piperazine-2,5-dione was done using a pure standard. A greater number of peaks which were also better defined were obtained using the ion-pair reversed-phase method, and open and closed beta-lactam ring polymer forms could be distinguished. Using the gel permeation method, only a few monomer, piperazine-2,5-dione, dimer, trimer and combined amoxicillin trimer and tetramer peaks were obtained with water, although those obtained were quite well defined. The data on the time-course of formation of the oligomers and the amoxicillin degradation product were virtually identical by both methods.
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 41 (1995), S. 148-152 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; On-column fluorimetric detection ; Gradient elution ; Dansyl amino acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Fluorimetric detection in the presence of a stationary phase has been applied to gradient elution of dansyl amino acids in liquid chromatography. A 1.5 mm ID quartz tube packed with the same materials as the separation column was employed for the flow cell. Conventional-size columns were employed. The peak height of analytes increased with increasing retention owing to focusing and environmental effects of the stationary phase, leading to improvements in sensitivity, which was pronounced for analytes eluting late. The lower the gradient, the larger the improvement in sensitivity achieved. Detection limits were improved by a factor of up to 5.1 by fluorimetric detection using the packed flow cell, compared with those achieved using a common empty flow cell.
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  • 83
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; LC-MS ; Cinchona alkaloids ; New column packing materials
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A major problem in the HPLC analysis of alkaloids is the poor peak shape and consequently low resolution, due to the interactions of the basic alkaloids with the residual acidic silanol groups of most reversed phase materials. The performance of new packing materials specially designed for the separation of basic compounds has been studied using mobile phases without the special additives commonly applied in the analysis of alkaloids. Strongly basic Cinchona alkaloids were used as test compounds. Retention characteristics and selectivities of each material were studied, after mobile phase optimisation for the column. The influence of the major factors (nature and content of the organic modifier, pH value, salt concentration) affecting resolution was studied. The mobile phases were chosen so that they could be used in thermospray LC-MS. The addition of salts to the mobile phase improves separation but in general the modification of the mobile phase gave little change in selectivity. The performance of silicabased C18 material proved superior to the polymer materials tested.
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  • 84
    ISSN: 1618-2545
    Schlagwort(e): consecutive planting ; Phoma sp. ; plant growth-promotion ; potting medium ; soybean ; wheat ; zoysiagrass rhizosphere fungi
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Several isolates ofPhoma sp., certain nonsporulating fungi, as well asPenicillium andTrichoderma, all isolated from zoysiagrass rhizosphere, promoted growth of wheat and soybean under greenhouse conditions. However, the ability of these rhizosphere fungi to enhance plant growth varied with the crop tested. For example, most of the fungi effectively promoted the growth of wheat, whereas only a few fungi were effective on soybean. In consecutive plantings of wheat and soybean grown in soil previously infested with these zoysiagrass rhizosphere fungi, the growth promotion ability of the fungi was lowered. However, addition of fresh potting medium appeared to restore their growth-promotive effects. It appears that the activation of plant growth-promoting fungi in soil might depend on the availability of organic substrates to colonize, as evidenced by the promotion of plant growth.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Molecular breeding 5 (1999), S. 561-568 
    ISSN: 1572-9788
    Schlagwort(e): wheat ; milling yield ; QTL mapping ; RFLP ; microsatellite
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A partial genetic linkage map constructed using 150 single seed descent (SSD) lines generated from a cross between the hexaploid wheat varieties ‘Schomburgk’ and ‘Yarralinka’ was used to identify loci controlling milling yield. Milling yield data were obtained using seed collected from field trials conducted at different sites over two seasons. The estimated broad-sense heritability of milling yield in this population was calculated as 0.48. In the preliminary analysis, two regions were identified on chromosomes 3A and 7D, which were significantly associated with milling yield and accounted for 22% and 19% of the genetic variation, respectively. Bulked segregant analysis in combination with AFLP identified other markers linked to these loci, as well as an additional region on chromosome 5A, which accounted for 19% of the genetic variation. The applicability of these markers as selection tools for breeding purposes is discussed.
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  • 86
    ISSN: 1572-9788
    Schlagwort(e): insect resistance ; aphids ; GNA ; lectins ; transgenic plants ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Transgenic wheat plants containing the gene encoding snowdrop lectin (Galanthus nivalis agglutinin; GNA) under the control of constitutive and phloem-specific promoters were generated through the particle bombardment method. Thirty-two independently derived plants were subjected to molecular and biochemical analyses. Transgene integration varied from one to twelve estimated copies per haploid genome, and levels of GNA expression from 0 to ca. 0.2% of total soluble protein were observed in different transgenic plants. Seven transgenic plants were selected for further study. Progeny plants from these parental transformants were selected for transgene expression, and tested for enhanced resistance to the grain aphid (Sitobion avenae) by exposing the plants to nymphal insects under glasshouse conditions. Bioassay results show that transgenic wheat plants from lines expressing GNA at levels greater than ca. 0.04% of total soluble protein decrease the fecundity, but not the survival, of grain aphids. We propose that transgenic approaches using insecticidal genes such as gna in combination with integrated pest management present promising opportunities for the control of damaging wheat pests.
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  • 87
    ISSN: 1572-9788
    Schlagwort(e): wheat ; DNA markers ; yellow rust resistance ; Yr17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The Yr17 gene, which is present in many European wheat cultivars, displays yellow rust resistance at the seedling stage. The gene introduced into chromosome 2A from Aegilops ventricosa was previously found to be closely linked (0.5 cM) to leaf and stem rust resistance genes Lr37 and Sr38, respectively. The objective of this study was to identify molecular markers linked to the Yr17 gene. We screened with RAPD primers, for polymorphism, the DNAs of cv. Thatcher and the leaf rust-resistant near-isogenic line (NIL) RL 6081 of cv. Thatcher carrying the Lr37 gene. Using a F2 progeny of the cross between VPM1 (resistant) and Thésée (susceptible), the RAPD marker OP-Y15580 was found to be closely linked to the Yr17 gene. We converted the OP- Y15580 RAPD marker into a sequence characterized amplified region (SCAR). This SCAR marker (SC-Y15) was linked at 0.8 ± 0.7 cM to the Yr17 resistance gene. We tested the SC-Y15 marker over a survey of 37 wheat cultivars in order to verify its consistency in different genetic backgrounds and to explain the resistance of some cultivars against yellow rust. Moreover, we showed that the Xpsr150-2Mv locus marker of Lr gene described by Bonhomme et al. [6] which possesses A. ventricosa introgression on the 2A chromosome was also closely linked to the Yr17 gene. Both the SCAR SC-Y15 and Xpsr150-2Mv markers should be used in breeding programmes in order to detect the cluster of the three genes Yr17, Lr37 and Sr38 in cross progenies.
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  • 88
    ISSN: 1572-9788
    Schlagwort(e): leaf rust ; molecular marker ; receptor-like kinase ; resistance breeding ; resistance gene ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract We recently showed that the Lr10 wheat leaf rust resistance gene cosegregated with the candidate resistance gene Lrk10 which encodes a putative receptor-like kinase. The aim of this study was to develop Lrk10-derived molecular markers for the detection of the Lr10 gene in breeding material. Different subfragments of Lrk10 were tested as RFLP markers for the Lr10 resistance gene. The most specific fragment (Lrk10-6) was converted into the PCR-based STS marker STSLrk10-6. Both the RFLP and the STS marker did not give a signal with near isogenic lines containing a different Lr gene. The applicability of these markers for the detection of Lr10 in genetically diverse material was tested with 62 wheat and spelt breeding lines, mostly from European breeding programmes. Twelve varieties known to have Lr10 showed the same alleles as the originally characterized line ThatcherLr10. Most of the lines with unknown composition at the Lr10 locus had a null allele with both the RFLP marker Lrk10-6 and the marker STSLrk10-6 whereas 20% of the lines had a different allele. For six lines, including a traditional spelt variety derived from a landrace, both markers showed the same allele as Thatcher Lr10. Artificial infections of these lines with an isolate avirulent on Lr10 resulted in a hypersensitive reaction of all these lines, indicating also the presence of the Lr10 resistance gene. These data demonstrate that the markers derived from sequences of Lrk10 are highly specific for the Lr10 gene in breeding material of very diverse genetic origin. The markers will allow the defined deployment of Lr10 in wheat breeding programmes and will contribute to the elucidation of the role of Lr10 in polygenic resistances against leaf rust.
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Molecular breeding 3 (1997), S. 177-181 
    ISSN: 1572-9788
    Schlagwort(e): bulked segregant analysis ; H21 ; near-isogenic lines (NILs) ; RAPD ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Near-isogenic lines in conjunction with bulked segregant analysis were used to identify a DNA marker in wheat (Triticum aestivum L.) associated with the H21 gene conferring resistance to biotype L of Hessian fly [Mayetiola destructor (Say)] larvae. Near-isogenic lines were developed by backcross introgression BC3F3:4 (‘Coker 797’ * 4 / ‘Hamlet’) and differed by the presence or absence of H21 (on 2RL) derived from ‘Chaupon’ rye (Secale cereale L.). Bulked DNA samples were prepared from near-isogenic lines and BC3F2 population individuals segregating for reaction to Hessian fly biotype L and screened for random amplified polymorphic DNA markers using 46 10mer primers. Random-amplified polymorphic DNA markers from resistant and susceptible individuals and parental lines were scored and these data were used to identify a 3 kb DNA fragment that was related to the occurrence of H21. This fragment was amplified from DNA isolated from Hamlet, a near-isogenic line carrying 2RL, and bulked DNA from resistant BC3F2 individuals, but not from the recurrent parent Coker 797 or DNA bulks from susceptible BC3F2 plants. Analysis of 111 BC3F2 segregating individuals and BC3F2:3 segregants confirmed the co-segregation of the 3 kb DNA marker with the H21 resistance gene to Hessian fly. Use of this marker could facilitate more rapid screening of plant populations for Hessian fly resistance and monitoring the introgression of H21.
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  • 90
    ISSN: 1573-8469
    Schlagwort(e): Central Europe ; powdery mildew ; wheat ; complexity of pathotypes ; Erysiphe graminis f.sp. tritici ; stabilizing selection ; survey ; virulence analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In 1993–1996, the virulence of regional populations of the wheat powdery mildew pathogen (Erysiphe graminis DC f. sp. tritici Marchal) from the Czech Republic, Austria, Hungary and Slovakia against 13 resistance genes was investigated. The populations differed mainly at the regional level. Populations from the Czech Republic, mainly from the western regions, showed higher values of virulence against the Pm4b gene. Lower frequency of virulence against Pm4b was found in Austria, and the lowest value was observed in Hungary. The differences in frequencies of virulence against Pm4a and Pm4b showed a similar geographic pattern across the four countries: a continuous decline from west to east and from north to south. Virulence against Pm2 decreased in all countries considered; virulence to pm5, Pm6, Pm8 and Mli was high throughout. Genes and gene combinations that can ensure a relatively effective biological protection against this pathogen across Central Europe at present are Pm3b, Pm2+Mld and Pm1+2+9. Czech and Slovak populations were the most complex: virulence complexity reached a maximum in Slovakia in 1994. A similar evolution, though less significant, was observed in the Czech Republic. Data on complexity of isolates suggest that Central European populations of wheat powdery mildew tend to reach an intermediate level representing the optimal number of virulence genes. This process is probably a consequence of stabilizing selection.
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plant pathology 105 (1999), S. 629-641 
    ISSN: 1573-8469
    Schlagwort(e): wheat ; Triticum spp. ; Septoria tritici ; septoria tritici blotch of wheat Stagonospora nodorum ; stagonospora nodorum blotch of wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plant pathology 101 (1995), S. 701-704 
    ISSN: 1573-8469
    Schlagwort(e): Cephalosporium gramineum ; Cephalosporium stripe ; rye ; susceptibility ; triticale ; wheat ; winter cereals
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Field experiments with winter cereals grown on soil inoculated withC. gramineum showed that wheat and rye cultivars possess some resistance to the pathogen, while the triticale cultivars were the most susceptible. Higher tolerance of the tested wheat cultivars was connected mainly with slow development of disease symptoms; rye cultivars had, on average, lower percentages of plants infected byC. gramineum. The greatest variation in susceptibility toC. gramineum occurred among the selected cultivars of triticale.
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plant pathology 101 (1995), S. 695-699 
    ISSN: 1573-8469
    Schlagwort(e): Pseudocercosporella herpotrichoides ; eyespot ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Apothecia of the eyespot fungus,Tapesia yallundae, were found on 0–18% of straws in plots of wheat stubble in February–March 1994. The fungicides carbendazim, prochloraz or carbendazim plus prochloraz had been applied repeatedly to the same plots in each of the previous 9 years in which successive wheat crops had been grown. The factors most strongly correlated with the incidence of apothecia were the incidence and severity of eyespot in the preceding wheat crop and the frequency of carbendazim-resistant W-type fungus in populations recovered from that wheat crop. Plots treated with carbendazim, which had previously had more disease and more resistance to carbendazim in the pathogen population relative to untreated plots, therefore yielded most apothecia. Plots treated with prochloraz, which had selected for predominantly R-type fungus and decreased eyespot, yielded few apothecia. Single-ascospore isolates were all of the W-type and were more frequently carbendazim-sensitive than expected, except those from plots treated only with carbendazim. None showed decreased sensitivity to prochloraz. The implications of applying fungicides regularly for controlling eyespot on the capability of the eyespot fungus for genetic variation through sexual reproduction are discussed.
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Aquaculture international 4 (1996), S. 237-252 
    ISSN: 1573-143X
    Schlagwort(e): Calcification ; Environmental disturbances ; Eumelanin ; Great scallop (Pecten maximus) ; Shell colour ; microstructure and melanization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Modifications of great scallop (Pecten moximus) shells have been noticed in many sites of scallop fisheries in Brittany, especially in shallow waters. These calcification abnormalities are linked to the appearance of a brown colouration of the internal calcified shell layer, due to the presence of a eumelanin associated with the insoluble organic matrix of the biocrystals. The appearance of this pigment generates many disturbances of the calcified foliated microstructure of the scallop internal shell layer. The mantle structure is not modified in brown shells as compared with white ones. No pathogenic signs such as hyperplasia or haemocytic infiltration have been observed. According to this observation, we hypothesize that the brown colour phenomenon is more a result of environmental disturbance rather than a symptom of a pathogenic disease. The colour abnormalities of the internal shell layer can be detected by a spectral analysis of its reflectance before it can be detected with the naked eye. This method, correlated to microstructural observations, gives a rapid and precise analysis of the appearance of the pigmentation on adult or juvenile scallops. It may be a useful method for the evaluation of the influence of environmental parameters, for example, on calcification and its abnormalities.
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Chromosome research 6 (1998), S. 339-344 
    ISSN: 1573-6849
    Schlagwort(e): Leymus ; meiosis ; molecular cytogenetics ; wheat ; wide-hybrids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Meiosis was examined in pollen mother cells of F1 hybrids made from crosses between wheat (Triticum aestivum) and lymegrass (Leymus arenarius and L. mollis). Fluorescence genomic in situ hybridization detected pairing between wheat and lymegrass chromosomes during prophase I and metaphase I. Such pairing, when resulting in bivalent formation, was likely to yield correct disjunction, and hence intergenomic recombination could be incorporated into the gametes. Bivalents in these hybrids, however, were more frequently formed between chromosomes of the same parental origin. Univalents were common, whereas multivalents were not clearly detected. Meiotic behaviour in some cells was not totally aberrant, and this may have accounted for the presence of normal pollen. The results are discussed in relation to intergenomic pairing, meiotic behaviour in wide-hybrids and genome relationships, including the Leymus genome origin.
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  • 96
    ISSN: 1573-6849
    Schlagwort(e): in situ hybridization ; intermediate wheatgrass ; translocation ; virus resistance ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Fluorescencein situ hybridization (FISH) was used to determine the breakpoint of the translocation chromosome in two bread wheat (Triticum aestivum) germplasm lines withThinopyrum intermedium chromatin carrying resistance to either wheat streak mosaic virus (WSMV) or barley yellow dwarf virus (BYDV). In addition, genome-specific random amplified polymorphic DNA (RAPD) markers were used to ascertain the genomic sources of theTh. intermedium chromosomes carrying the WSMV or BYDV resistance. CI17766, a WSMV-resistant wheat germplasm line derived from induced homoeologous pairing by using theph1b mutant, had a translocation chromosome composed of the complete 4AL and about 45% of proximal 4AS from wheat, and the entire 4ES ofTh. intermedium. The BYDV-resistant translocation line, TC14, derived from tissue culture, had a very short distal segment of 7StL fromTh. intermedium terminally attached to 56% of the proximal 7DL. These observations indicate that translocations in these wheat germplasm lines did not involve centromeric breaks and fusion but were a result of homoeologous chromosome recombination.
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 35 (1997), S. 167-177 
    ISSN: 1573-5028
    Schlagwort(e): comparative genetics ; rice ; barley ; wheat ; Arabidopsis ; flowering time (heading date) ; photoperiod ; vernalization ; earliness
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Analysis of genes controlling flowering time (heading date) contributes to our understanding of fundamental principles of plant development and is of practical importance because of the effects of flowering time on plant adaptation and crop yield. This review discusses the extent to which plants may share common genetic mechanisms for the control of flowering time and the implications of such conservation for gene isolation from the major cereal crops. Gene isolation may exploit the small genome of rice in map-based approaches, utilizing the conservation of gene order that is revealed when common DNA markers are mapped in different species. Alternatively, mechanisms may be conserved within plants as a whole, in which case genes cloned from the model dicot Arabidopsis thaliana provide an alternative route.
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  • 98
    ISSN: 1573-5028
    Schlagwort(e): barley ; kinase ; leaf rust ; receptor-like kinase ; resistance ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In plants, several types of receptor-like kinases (RLK) have been isolated and characterized based on the sequence of their extracellular domains. Some of these RLKs have been demonstrated to be involved in plant development or in the reaction to environmental signals. Here, we describe a RLK gene family in wheat (wlrk, wheat leaf rust kinase) with a new type of extracellular domain. A member of this new gene family has previously been shown to cosegregate with the leaf rust resistance gene Lr10. The diversity of the wlrk gene family was studied by cloning the extracellular domain of different members of the family. Sequence comparisons demonstrated that the extracellular domain consists of three very conserved regions interrupted by three variable regions. Linkage analysis indicated that the wlrk genes are specifically located on chromosome group 1 in wheat and on the corresponding chromosomes of other members of the Triticeae family. The wlrk genes are constitutively expressed in the aerial parts of the plant whereas no expression was detected in roots. Protein immunoblots demonstrated that the WLRK protein coded by the Lrk10 gene is an intrinsic plasma membrane protein. This is consistent with the hypothesis that WLRK proteins are receptor protein kinases localized to the cell surface. In addition, we present preliminary evidence that other disease resistance loci in wheat contain genes which are related to wlrk.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    ISSN: 1573-8469
    Schlagwort(e): Bacillus thuringiensis ; biological control ; Helicotylenchus multicinctus ; nematicide ; numerical response ; Paecilomyces marquandii ; Radopholus similis ; Streptomyces costaricanus ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effect of 24 treatment combinations of cultures of Streptomyces costaricanus sp. nov. (ATCC55274), Bacillus thuringiensis (ATCC55273) and a strain of Paecilomyces marquandii, nematicide (cadusaphos), and/or wheat mash on growth and response of potted banana plants (Musa AAA) and populations of Radopholus similis, Helicotylenchus multicinctus and free living nematodes were studied in Río Frío, Costa Rica. The best plant responses (height, leaf numbers, healthy root weight), lowest numbers of plant parasitic nematodes and highest numbers of free living nematodes were observed for treatments containing wheat as a component. Two treatments, viz. wheat + Streptomyces costaricanus (200-ml culture) and wheat + P. marquandii (200-ml culture), gave the overall best results. Numbers of free living nematodes increased up to 1500-fold only for treatments containing wheat. Significant positive correlations existed between numbers of free living nematodes and shoot weight, healthy root biomass, plant height, and leaf numbers. Non-wheat treatments, including nematicide only, gave the poorest responses in general. Observations of nematodes sampled 50 days following planting in wheat-containing treatments showed most of the free-living nematodes (≈ 90%) to be infected by nematophagous fungi (species not recorded). The results show that an organic amendment to soil, with or without a microbial component, can be an effective inducer of processes that regulate plant-parasitic nematode populations in soil.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 39 (1999), S. 915-926 
    ISSN: 1573-5028
    Schlagwort(e): programmed cell death ; wheat ; endosperm ; ethylene ; nucleases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Although maize endosperm undergoes programmed cell death during its development, it is not known whether this developmental feature is common to cereals or whether it arose inadvertently from the selection process that resulted in the enlarged endosperm of modern maize. Examination of wheat endosperm during its development revealed that this tissue undergoes a programmed cell death that shares features with the maize program but differs in some aspects of its execution. Cell death initiated and progressed stochastically in wheat endosperm in contrast to maize where cell death initiates within the upper central endosperm and expands outward. After a peak of ethylene production during early development, wheat endosperm DNA underwent internucleosomal fragmentation that was detectable from mid to late development. The developmental onset and progression of DNA degradation was regulated by the level of ethylene production and perception. These observations suggest that programmed cell death of the endosperm and regulation of this program by ethylene is not unique to maize but that differences in the execution of the program appear to exist among cereals.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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