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  • 1
    Electronic Resource
    Electronic Resource
    Stable and metastable phases in Agl-containing silver borate glasses (1983)
    Springer
    Journal of thermal analysis and calorimetry 28 (1983), S. 273-278 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Im System Agl-Ag2O-B2O3 werden die thermischen Bedingungen und die Komponentenverhältnisse, unter denen eine Glasphase existent ist, untersucht. Der Bereich der Mischbarkeit der Komponenten wurde durch direkte visuelle Beobachtung bei einer Temperatur von 1000°C untersucht, bei der das System über den ganzen Bereich der Zusammensetzung hinweg flüssig ist. Der ausgedehnte Bereich der Glasbildung im untersuchten System wurde durch kombinierte röntgendiffraktometrische und differentialthermoanalytische Messungen bestimmt. Der Zusammenhang zwischen Transformationstemperatur und Zusammensetzung des Glases wird diskutiert. Eine Serie von Gläsern wurde über längere Zeit oberhalb der Glastransformationstemperatur getempert, um ein “Gleichgewichts”-Phasendiagramm für das System zu bestimmen. Bei thermischer Behandlung werden in den getemperten Materialien verschiedene kristalline Verbindungen gebildet.
    Abstract: Резюме Изучена термоустойч ивость и область стеклообразования с истемы Agl-Ag2O-B2O3. Область смешивае мости компонент была исследована прямым в изуальным наблюдением при 1000°С, г де система является жидкой во всей област и состава. Комбинированием рен тгенографических и Д ТА измерений, определена область с теклообразования в этой системе. Обсужд ена зависимость температуры расстек ловывания от состава стекла. Для определения формы “равновесной” фазов ой диаграммы системы, серия стекол была под вергнута отжигу выше температуры расстек ловывания при различ ных интервалах времени. А нализ оттоженных обр азцов показал, что в процесс е термической обработки образуетс я несколько кристаллических сое динений.
    Notes: Abstract This paper studies the thermal stability and the glass formation region the Agl-Ag2O-B2O3 system. The miscibility range of the components has been investigated by direct visual observation at 1000°C, i.e. where the system is liquid over the entire compositional range. By combining X-ray and differential thermal analysis (DTA) measurements, the large region of glass formation of the system has been determined. The dependence of the glass transition temperature upon the glass composition is discussed. Series of glasses have been annealed over extended time intervals above the glass transition temperature in order to characterize the “equilibrium” phase diagram for the system. Analysis of the annealed materials shows that several crystalline compounds form upon annealing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01983260
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  • 2
    Electronic Resource
    Electronic Resource
    Intracellular proteases from the extremely thermophilic archaebacteriumSulfolobus solfataricus (1991)
    Springer
    Cellular and molecular life sciences 47 (1991), S. 1057-1060 
    Details
    ISSN: 1420-9071
    Keywords: Proteases ; thermostability ; archaebacterium ; S. solfataricus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Proteolytic activities from the extremely thermoacidophilic archaebacteriumSulfolobus solfataricus were detected with the aid of synthetic substrates in a cell extract fractionated by gel filtration. Two aminopeptidases (aminopeptidase I and II), three endopeptidases (proteinase I, II and III) and one carboxypeptidase could be identified. Experiments carried out with protease inhibitors led to the identification of the exopeptidases as metalloproteases. Proteinases I and II behaved as chymotrypsin-like serine proteases, and proteinase III as a cysteine protease with a trypsin-like specificity. Molecular weight values assessed with the aid of marker proteins were as follows: aminopeptidase I, 〉450 kDa; aminopeptidase II, 170 kDa; carboxypeptidase, 160 kDa; proteinase I, 115 kDa; proteinase II, 32 kDa; proteinase III, 27 kDa. On incubation for 15 min they retained most of their activity up to a temperature of 90°C, with the sole exception of proteinase II, which was rapidly inactivated at 60°C. Protease content was also determined in crude extracts from cells grown in a mineral medium both to the stationary and to the exponential phase, with glucose or with yeast extract as carbon sources. No dramatic change was detected depending on the growth phase; however, carboxypeptidase level was three- to four-fold higher when yeast extract was present in the medium instead of glucose; this might suggest an involvement of this enzyme in the digestion of extracellularly available peptides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923341
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  • 3
    Electronic Resource
    Electronic Resource
    Metabolism of lignin-related compounds by Rhodococcus rhodochrous: bioconversion of anisoin (1991)
    Springer
    Applied microbiology and biotechnology 36 (1991), S. 410-415 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The ability of the nocardioform actinomycete Rhodococcus rhodochrous to metabolize selected lignin model compounds was studied. The compounds studied included cinnamic and ferulic acids and dimers possessing intermonomeric linkages that are characteristic of the lignin molecule. R. rhodochrous reduced the carbonyl group of anisoin, a 1,2-diarylethane (β-1) structure to (1R,2R)-1,2-bis(4-methoxyphenyl)ethane-1,2-diol with an enantiomeric excess of .98%. Cleavage of 1,2-diarylethane and β-O-4 structures by this strain could not be detected under our metabolic conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00208166
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  • 4
    Electronic Resource
    Electronic Resource
    Anaerobic biodegradation of m-, o-, p-hydroxycinnamic acid by an adapted microbial consortium (1986)
    Springer
    Cellular and molecular life sciences 42 (1986), S. 1254-1256 
    Details
    ISSN: 1420-9071
    Keywords: Anaerobic metabolism ; acclimated consortium ; hydroxycinnamic acid isomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The degradation of ortho-, meta- and para-hydroxycinnamic acid by an acclimated consortium (or ‘mixed bacterial culture’) was investigated. The biodegradation was evaluated by monitoring substrate disappearance. The relative rates of consumption were in the order: para〉meta〉 〉ortho. Only in the catabolism of meta-and para-hydroxycinnamic acid, the demolition of the side chain by the loss of a C1 unit is involved. The utilization of para-hydroxycinnamic acid by the consortium occurred rapidly and completely within a 38-day incubation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01946411
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  • 5
    Electronic Resource
    Electronic Resource
    NMR of water in biological systems (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 1019-1032 
    Details
    ISSN: 0392-6737
    Keywords: Nuclear magnetic resonance and relaxations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è spesso assunto che la relazione tra mobilità e risposta NMR dell'acqua nei sistemi biologici (ossia eterogenei dinamicamente in quanto composti da fasi liquide e fasi solide) sia esprimibile mediante le equazioni di rilassamento di Bloembergen-Purcell-Pound (BPP). Però l'uso della teoria BPP richiede la presenza di un sistema tridimensionale, infinito ed isotropo. In questo lavoro si mostra che la mera presenza di superfici solide può far comparire andamenti «alla solido» nella risposta NMR di un liquido la cui dinamica microscopica non è mutata dall'interazione con le superfici. Alcuni di questi effetti «topologici» delle superfici si possono ricondurre alle anomalie della bassa dimensionalità che, da alcuni anni, sono investigate attivamente. L'ordine di grandezza degli effetti «topologici» è stimato per geometrie semplici ed un lavoro, a questo collegato, effettua un confronto tra teoria ed esperimento.
    Abstract: Резюме Предполагается, что существует простое соотношение мечду динамикой воды в гетерогенных системах и ЯМР откликом. Это соотношение обычно выражается с помощью уравнений Бломбергена-Пурселя-Паунда для релаксации и фазовой модели. Однако, использование теории Бломбергена-Пурселя-Паунда предполагает, что движения происходят в изотропном, бесконечном и трехмерном пространстве. Показывается, что наличие твердых поверхностей является причиной появления твердоподобных особенностей в ЯМР отклике жидкости, даже в том случае, если поверхности непосредственно не влияют на динамику. Некоторые из этих «топологических» или «непрямых» поверхностных эффектов являются аналогичными эффектам низкой размерности. Оценивается порядок величин этих эффектов для простых геометрий. В следующей статье проводится сравнение полученных результатов с экспериментом.
    Notes: Summary A simple relationship has been thought to exist between the dynamics of water in heterogeneous (liquid-solid) systems and the NMR response. This relationship is usually expressed by the Bloembergen-Purcell-Pound (BPP) equations for relaxation and the phase model. However, a requirement for the use of the BPP theory is that motions take place in an isotropic, infinite and three-dimensional space. It is shown that the mere presence of solid surfaces causes the appearance of solidlike features in the NMR response of the liquid even if its dynamics is directly affected by the surfaces. Some of these «topological» or «indirect» surface effects are of the same kind as the low-dimensionality effects. Their order of magnitude is estimated for simple geometries and by treating the liquid motion in a hydrodynamic approximation. Comparison with the experiment is carried on in a companion paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02457137
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  • 6
    Electronic Resource
    Electronic Resource
    NMR of water in biological systems (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 1033-1049 
    Details
    ISSN: 0392-6737
    Keywords: Nuclear magnetic resonance and relaxation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Qui si presenta una ricerca sperimentale sulla risposta NMR dell'acqua nel gastrocnemio di rana. I dati sono discussi sulla base dei modelli di «spazio ristretto», sv-. luppati in un lavoro precedente, i quali suppongono l'esistenza di una sola fase d'acquai Alcune caratteristiche della risposta NMR si possono facilmente spiegare con questi modelli, mentre altre mostrano l'esistenza di piú di una «fase» di acqua. Un lavoro di reinterpretazione di dati NMR è stato fatto esaminando lavori condotti su sistemi biologici e modello. Se ne trae il suggerimento che è spesso piú conveniente interpretali dati in termini di una sola specie acquosa, con mobilità media minore di quella della H2O libera, piuttosto che in termini di molte fasi, la caratterizzazione delle quali è piú che mai incerta.
    Abstract: Резюме Предлагаются экстенсивные исследования ЯМР отклика воды в мускульной ткани. Наши данные сравниваются с результатами, полученными в предыдущей работе, в которой развита «клеточная модель», предполагающая существование одной фазы воды. С помощью этих «клеточных моделей» легко объясняются некоторые особенности ЯМР отклика. Однако, другие особенности указывают на существование других фаз воды. Проводится анализ ЯМР данных для биологических и модельных систем, изученных в литературе. Мы предполагаем, что в большинстве случаев наиболее подходящей является интерпретация ЯМР данных в терминах одной фазы воды со средней подвижностью, соответствующей подвижности свободной воды, а не в термиаах несклльких фаз.
    Notes: Summary An extensive investigation of water NMR response in the muscular tissue (frog gastrocnemius) is presented. Our data are compared with the predictions of the «cage models» (discussed in a companion paper), which envisions a single water phase subjected to topological constraints. Several features of the NMR response are easily accounted for by the cage models. Instead, other features give clear evidence for the existence of different phases of water. We performed also an analysis of NMR data for biological and model systems studied in the literature. We suggest that, in most cases, it is more appropriate to interpret NMR data in terms of a single water phase with an average mobility somewhat reduced with respect to that of free water, rather than in terms of several ill-characterized phases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02457138
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  • 7
    Electronic Resource
    Electronic Resource
    Screening for FMR1 and FMR2 mutations in 222 individuals from Spanish special schools: identification of a case of FRAXE-associated mental retardation (1997)
    Springer
    Human genetics 〈Berlin〉 100 (1997), S. 503-507 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Fragile X syndrome is the most common inherited form of familial mental retardation. It results from a (CGG) n trinucleotide expansion in the FMR1 gene leading to the typical Martin-Bell phenotype. Clinical features vary depending on age and sex. Expansion of a (CCG) n repeat in the FMR2 gene corresponds to the FRAXE fragile site which lies distal to FRAXA and is also associated with mental retardation, but it is less frequent and lacks a consistent phenotype. Analysis of repeat expansions in these two genes allows the molecular diagnosis of these different entities. We report here the screening of the FRAXA and FRAXE mutations in 222 unrelated mentally retarded individuals attending Spanish special schools. PCR and/or Southern blotting methods were used. We detected full mutations in the FMR1 gene in 11 boys (4.9%) and 1 boy (0.5%) with a CCG repeat expansion in the FMR2 gene. The latter shows mild mental retardation with psychotic behaviour and no remarkable physical traits. Molecular studies revealed a mosaicism for methylation in the FMR2 gene. This case supports the observation that expansions greater than 100 repeats can be partially methylated and cause the phenotype.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004390050542
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  • 8
    Electronic Resource
    Electronic Resource
    Molecular analysis of the (CGG)n expansion in the FMR-1 gene in 59 Spanish fragile X syndrome families (1994)
    Springer
    Human genetics 〈Berlin〉 94 (1994), S. 395-400 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The fragile X mental retardation syndrome is caused by an expansion of a trinucleotide repeat (CGG)n in the FMR-1 gene. Molecular genetic study of fragile X provides accurate diagnosis and facilitates genetic counseling in families with affected members. We present here the molecular study of 59 Spanish fragile X syndrome families using probe StB 12.3 and the polymerase chain reaction (PCR) of the (CGG)n repeat sequence of the FMR-1 gene. The results obtained have allowed us to characterize 455 individuals, including eight prenatal diagnoses. The clinical diagnosis of fragile X in 89 affected males was confirmed, 137 female carriers were identified (48 of whom were mentally retarded), 176 individuals “at risk” were found not to have the expansion, and 12 cases of normal transmitting males (NTM) were detected. In the sample studied, no de novo mutations were detected, nor any mutation different from that described for the (CGG)n expansion. One nonmentally retarded male was detected as having an unmethylated CpG island for the FMR-1 gene, but with more than 200 CGG repeats (high functioning male). The analysis of the (CGG)n repeat in 208 normal chromosomes gave an allele distribution similar to that in other Caucasoid population groups, with alleles of 29 and 30 CGG repeats accounting for 46% of the chromosomes. The combination of Southern analysis and PCR of the (CGG)n repeat is highly efficient for diagnosis, compared with cytogenetic techniques, especially in the detection of female carriers, NTMs, and prenatal diagnosis, enabling accurate genetic counseling to be provided in all cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00201600
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  • 9
    Electronic Resource
    Electronic Resource
    gaMS-1: a gametophytic male sterile mutant in maize (1996)
    Springer
    Sexual plant reproduction 9 (1996), S. 216-220 
    Details
    ISSN: 1432-2145
    Keywords: Key words Maize pollen ; Male sterility ; Microsporogenesis ; Gametophytic gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Several pollen-specific genes from different species have been isolated and characterized at the molecular level, but the precise role of most of them is unknown. Mutant analysis represents a direct approach to uncovering gene function, but the paucity of available mutants affecting pollen development and/or function and the poor characterization of the known mutants have so far limited the exploitation of this approach. Here we present the cytological characterization of gametophytic male sterile-1 (gaMS-1), a maize mutant that we identified in a program of transposon insertion mutagenesis for the production of mutations in gametophytically acting genes involved in microsporogenesis. gaMS-1 is expressed during or immediately after the first microspore division and leads to the production of immature, non-functional pollen grains. The mutation appears to affect the events leading to the developmental switch that follows the first microspore mitosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004970050034
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  • 10
    Electronic Resource
    Electronic Resource
    gaMS-1: A gametophytic male sterile mutant in maize (1996)
    Springer
    Sexual plant reproduction 9 (1996), S. 216-220 
    Details
    ISSN: 1432-2145
    Keywords: Maize pollen ; Male sterility ; Microsporogenesis ; Gametophytic gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several pollen-specific genes from different species have been isolated and characterized at the molecular level, but the precise role of most of them is unknown. Mutant analysis represents a direct approach to uncovering gene function, but the paucity of available mutants affecting pollen development and/or function and the poor characterization of the known mutants have so far limited the exploitation of this approach. Here we present the cytological characterization ofgametophytic male sterile-1 (gaMS-1), a maize mutant that we identified in a program of transposon insertion mutagenesis for the production of mutations in gametophytically acting genes involved in microsporogenesis.gaMS-1 is expressed during or immediately after the first microspore division and leads to the production of immature, nonfunctional pollen grains. The mutation appears to affect the events leading to the developmental switch that follows the first microspore mitosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02173101
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