Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Electronic Resource  (7)
  • aggregation  (4)
  • Protoplasts  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Involvement of human mucous saliva and salivary mucins in the aggregation of the oral bacteria Streptococcus sanguis, Streptococcus oralis, and Streptococcus rattus (1990)
    Springer
    Antonie van Leeuwenhoek 57 (1990), S. 245-252 
    Details
    ISSN: 1572-9699
    Keywords: aggregation ; mucins ; parotid saliva ; Streptococcus oralis ; Streptococcus rattus ; Streptococcus sanguis ; submandibular-/sublingual saliva
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The contribution of human parotid (Par) and submandibular/sublingual (SM/SL) saliva and of the human whole salivary mucin fraction (HWSM) to saliva-induced bacterial aggregation was studied for S. sanguis C476, S. oralis I581, and S. rattus HG 59. The mucous SM/SL saliva showed a much higher aggregation potency towards the S. sanguis and S. oralis strain than did the serous Par saliva. The SM/SL saliva-induced aggregation was observed after 30 min, at 60 min followed by the Par saliva-induced aggregation, and showed a 4-fold higher aggregation titer of 128 for S. sanguis, and an 8-fold higher titer of 516 for S. oralis. In contrast, the Par saliva showed a slightly higher aggregation activity than the SM/SL saliva towards S. rattus as judged by a twofold higher titer of 64. Morphologically, however, the SM/SL saliva-induced aggregation of S. rattus was far more pronounced as was also found for S. sanguis. Finally, the HWSM-induced aggregation showed a 4 to 8-fold higher titer than the originating salivary source, measuring 2048 for S. oralis and 128 for S. rattus. Moreover, no difference was observed in aggregation activity between the HWSM from whole saliva of a blood group O donor and the HWSM from SM/SL saliva of a blood group A donor. All the data point to an important, though not exclusive role of the human salivary mucin fraction in the saliva-induced aggregation of these strains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400156
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Protoplast preparation without centrifugation: plant regeneration of barley (Hordeum vulgare L.) (1994)
    Springer
    Plant cell reports 13 (1994), S. 188-192 
    Details
    ISSN: 1432-203X
    Keywords: Alginate films ; Barley ; Cell suspensions ; Plant regeneration ; Protoplasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using a modification of the alginate film culture technique we show that it is possible to prepare and culture tobacco mesophyll and barley cell suspension protoplasts without centrifugation. Comparable division frequencies and colony development were observed from protoplasts embedded with enzyme and protoplasts purified by centrifugation. A 3 × 30 min washing regime was found to be the minimum time necessary to remove the enzyme from the gelled alginate matrix. The procedure provides a more gentle method for isolating protoplasts. It has the additional benefit of recovering all of the cells released from the starting tissue. In particular, the smaller protoplasts that are frequently lost during conventional isolation, are maintained. In barley, we illustrate the use of the system for recovering plants from embryogenic protoplast-derived calli from the cultivars Dissa and Igri. Finally, using small volumes of enzyme (50 μl) single cell aggregates were used to isolate and culture protoplasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239890
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Individual selection, culture and manipulation of higher plant cells (1987)
    Springer
    Theoretical and applied genetics 73 (1987), S. 769-783 
    Details
    ISSN: 1432-2242
    Keywords: Microculture ; Electrofusion ; Microinjection ; Karyoplasts ; Cytoplasts ; Protoplasts ; Plant regeneration ; Conditioning ; Brassica napus ; Nicotiana tabacum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Due to the heterogeneity in morphology, physiological and morphogenetical capabilities of higher plant cells in mass culture, the development of methods for individually culturing defined cells seemed to be useful and necessary. Individual cell culture represents a powerful tool for studies on the physiology of different cell types, the analysis of differentiation programs, the genetic manipulation of plant cells and cell-cell interactions. An improved microculture system based on a computer-controlled set-up for the efficient selection, transfer and individual culture of defined higher plant cells until regeneration of whole plants is described. Related experimental approaches for individually manipulating higher plant cells under controlled conditions, such as electrofusion of defined pairs of protoplasts and subprotoplasts, cell reconstruction and intranuclear microinjection of protoplasts and karyoplasts — mainly performed with cells of the crop plant Brassica napus L. — are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00289379
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    A cytokinin-sensitive mutant of the moss,Physcomitrella patens, defective in chloroplast division (1989)
    Springer
    Protoplasma 152 (1989), S. 1-13 
    Details
    ISSN: 1615-6102
    Keywords: Physcomitrella protonemata ; Chloroplast division ; Cytoskeleton ; Cell division abnormalities ; Microinjection ; Moss mutant ; Protoplasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An X-ray induced mutant (PC22) of the moss,Physcomitrella patens was analysed with respect to its morphology, physiology and suitability for microculture techniques. The mutant protonemata are defective in bud formation and in chloroplast division. As a consequence of the latter, giant chloroplasts are formed which disturb the development of the phragmoplast, the formation of regular cross walls, and cell division. Abnormal cross walls are rich in callose. The actin cytoskeleton was found to be less regularly developed in the mutant than in the wild type. Three-dimensional analysis of the microtubular arrangement with confocal laser scan microscopy demonstrates a close association between spindle- or phragmoplast- and “interphase”-microtubules. The deficiencies in chloroplast division and in bud formation can partly be compensated for by exogeneously applied cytokinin. The suitability of this particular developmental mutant for further studies was shown by regeneration of protoplasts in microculture and microinjection of the fluorochrome Lucifer yellow into the chloroplast.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01354234
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Aggregation of oral bacteria by human salivary mucins in comparison to salivary and gastric mucins of animal origin (1990)
    Springer
    Antonie van Leeuwenhoek 58 (1990), S. 255-263 
    Details
    ISSN: 1572-9699
    Keywords: aggregation ; animal mucins ; human salivary mucin ; oral bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Seventeen strains of oral bacteria of the genera Actinomyces (5), Bacteroides (3), and Streptococcus (9) were tested for aggregation by the human whole salivary mucin fraction (HWSM) in comparison to three types of animal mucin preparations from submandibular glands of cow (BSM) and sheep (OSM), and from the stomach of pig (PGM). Considerable variation was seen with respect to the rate and titer of aggregation induced by these mucins. The aggregating activity of HWSM varied widely among the different bacterial strains. The Bacteroides group showed hardly any induced aggregation, whereas the final aggregation titers varied for S. sanguis (3 strains) between 12 and 48, for S. oralis (3 strains) between 6 and 48, for the S. mutans group (3 strains) between 6 and 96, and for the five Actinomyces strains even between 6 and 192. For a particular strain, similar differences in titer were seen between the four mucins. For a human salivary mucin (MG-2) it has been described that sialic acid in the sequence NeuAc (α2,3)Gal(β1,3)GalNac- was specifically involved in the interaction with S. sanguis strains, in contrast to S. rattus BHT. Our results, however, indicate that this sugar sequence is not a prerequisite for the aggregation of S. sanguis, as animal mucins, devoid of this structure, were equally well or even better capable of inducing aggregation. On the other hand, desialization of BSM and OSM largely abolished their aggregating capability towards S. rattus BHT. Moreover, it was found that BSM and OSM, which are comparable with respect to their major oligosaccharide structure, show considerable differences in aggregating activity towards the same bacterial strain. The results indicate that the interaction and aggregation of oral bacteria with mucins is not necessarily dictated by specific oligosaccharide structures of the mucins, but may be caused instead by common physico-chemical features of the mucins as well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00399337
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Comparison of different assays for the aggregation of oral bacteria by human whole saliva (1989)
    Springer
    Antonie van Leeuwenhoek 55 (1989), S. 109-122 
    Details
    ISSN: 1572-9699
    Keywords: aggregation ; microtiterplate assay ; oral bacteria ; phase-contrast microscopy ; saliva ; spectrophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract For comparison, human whole saliva-induced aggregation was studied by phase-contrast microscopy, spectrophotometry combined with macroscopic observations, and in microtiterplate assay under identical experimental conditions for Actinomyces viscosus HG 85 (T14-V) and HG 380 (T14-AV), Bacteroides gingivalis HG 66 (W 83), Streptococcus rattus HG 59 (BHT), and Streptococcus sanguis I HG 169. The entire process of formation, extension, and sedimentation of aggregates could merely be observed by the combination of these assays. The very first stages of aggregation could only be detected and quantitated by phase-contrast microscopy. Within 2 1/2 min. 50% of the A. viscosus, S. rattus, and S. sanguis cells were aggregated, denoted as T50. In microtiterplates, however, aggregates were observed in general only after sedimentation at 30–45 min of incubation, expressed as TA. For interpretation of the spectrophotometric curves, additional microscopic and macroscopic data were a prerequisite. The small decline in absorbance during the first 30–45 min (phase 1) corresponded to the formation and extension of non-sedimenting aggregates, whereas the subsequent pronounced fall in absorbance (phase 2) was caused by the massive sedimentation of aggregates. The moment of inflexion between both phases, TI, marked the onset of sedimentation of aggregates and corresponded very well with TA, at which time already 92–98% of the cells were aggregated as quantitated by microscopy. In conclusion, only by microscopy the formation and extension of aggregates could be observed within a few minutes and quantitated in terms of aggregation rate. From 30–45 min, merely the sedimentation of aggregates was visualized in microtiterplates, whereas the time course of the overall process was recorded indirectly by spectrophotometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00404751
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Aggregation of 27 oral bacteria by human whole saliva (1989)
    Springer
    Antonie van Leeuwenhoek 55 (1989), S. 277-290 
    Details
    ISSN: 1572-9699
    Keywords: Actinomyces ; aggregation ; Bacteroides ; oral bacteria ; saliva ; Streptococcus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twenty-seven oral strains of the genera Actinomyces (5), Bacteroides (3), and Streptococcus (19) were tested for aggregation by human whole saliva, as well as the effect of culture medium, Ca-ions, and bacteria concentration thereupon. Of the media tested, GF-broth gave rise to less interference by autoaggregation or higher aggregation titers than BHI and TSB, and was used throughout this study. In most cases, Ca-ions (1 mM) only enhanced the rate of induced aggregation, whereas raising the bacteria concentration increased the rate of both induce- and autoaggregation. The final titers, ranging from 1–64, were hardly affected by these parameters, except those of S. rattus HG 59 and S. mutans HG 199, which were respectively increased and decreased by Ca-ions. Saliva-induced aggregation was observed for 21 strains of A. viscosus, A. naeslundii, A. israelii, B. gingivalis, B. intermedius, S. cricetus, S. mutans, S. rattus, S. sanguis, and S. sobrinus, mostly within 15 min to 3 h. Seventeen of these strains also showed autoaggregation, usually well after the onset of induced aggregation. Any potential induced aggregation of B. gingivalis HG 91 was always masked by autoaggregation, as well as that of the S. mutans strains under a particular set of conditions. The aggregation rate and titer varied considerably in a mutually unrelated and strain-dependent way. These microtiterplate data were matched by the 5 spectrophotometric patterns observed for saliva-bacterial interaction, which moreover, gave the better differentiation between induced and autoaggregation. In conclusion, most strains tested can show rapid saliva-induced aggregation in a strain-dependent way, yet strongly affected by the experimental conditions and interference from autoaggregation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393856
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...