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  • 1
    ISSN: 1432-072X
    Keywords: Bdellovibrio ; Spirillum ; Cell wall ; Bdelloplast ; Lipoprotein ; Peptidoglycan ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In both freeze-etched and critical-point dried preparations examined by transmission and scanning electron microscopy, respectively, the outer surfaces of the cells of Spirillum serpens VHL assume a wrinkled appearance 10–15 min after challenge by Bdellovibrion bacteriovorus 109D. This wrinkling effect is believed (on circumstantial evidence) to be caused by the bdellovibrio's disruption of the cell wall lipoprotein of the Spirillum. With the exception of those topological changes caused by wrinkling, the outer membrane of the Spirillum cell wall retains a normal appearance as viewed in freeze-etched preparations, even after the Spirillum cell has been converted into a bdelloplast. Although the peptidoglycan layer of the Spirillum cell presumably is weakened somewhat by the invading Bdellovibrio, evidence obtained from freeze-fractured preparations of Spirillum bdelloplasts suggests that the peptidoglycan remains as a discrete cell wall layer, even though the Spirillum cell wall apparently has lost much of its rigidity. That the peptidoglycan backbone remains essentially intact, even after the Spirillum cell has been entered by the Bdellovibrio, is supported by the observation that the soluble amino sugar content of the culture medium, as determined by chemical analysis, does not rise even 5.0 h after the association of the Bdellovibrio with the Spirillum has begun.
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  • 2
    ISSN: 1432-072X
    Keywords: Bdellovibrio bacteriovorus ; Spirillum serpens ; Freeze Fracture ; Electron Microscopy ; Ultrastructure ; Membrane Damage ; Organismic Associations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The freeze-fracture technique and electron microscopy have been used to demonstrate that localized damage is inflicted upon the cytoplasmic membrane of Spirillum serpens VHL within 20 to 30 min after the start of its association with Bdellovibrio bacteriovorus 109D. This damage is not observed in uninfected Spirillum cells, nor in infected cells within the first 10 min. This damage takes the form of a “blister” which, when viewed stereoscopically in electron micrographs, is seen to project toward the interior of the Spirillum cell. Shortly after its formation, the blister becomes elaborated into a series of ridges which may assume forms ranging from an elaborate spiral to a series of loops or knots. The formation of a blister is shown to involve both the inner and outer leaves of the membrane bilayer, and evidence is presented to indicate that the blister site corresponds to the site of attachment of the Bdellovibrio cell. The hypothesis is proposed that this ultrastructural damage is the cytological basis for the controlled and localized leakage through the cytoplasmic membrane into the periplasmic space of the Spirillum cell at locations adjacent to the Bdellovibrio cell. It is suggested that this localized membrane damage may be the ultrastructural basis for the high efficiency with which bdellowvibrios are known to incorporate cytoplasmic materials from the other bacteria in whose periplasmic spaces they develop.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 30 (1958), S. 325-334 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The alfalfa wilt bacterium, Corynebacterium insidiosum, produces a water-insoluble blue substance which accumulates extracellularly. A number of factors (among them strain variation, temperature, pH, nutrition, crowding) have a considerable influence upon pigment production. Proper control of these factors led to a method for large-scale cultivation of C. insidiosum under conditions of good pigmentation. On the bases of absorption spectrum, solubility characteristics, and the properties of crystalline acetyl and benzoyl derivatives, the C. insidiosum pigment is believed to be identical with indigoidine—a pigment of unknown composition previously reported in Pseudomonas indigofera.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 36 (1960), S. 175-181 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 42 (1962), S. 289-298 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary From these observations, it can be concluded that V-forms and other angular cell arrangements in Arthrobacter atrocyaneus can arise in several different ways. As summarized diagrammatically in Fig. 5, the irregular cell conjunctions so characteristic of these corynebacteria might be the result of snapping post-fission movement, the germination of adjacent coccoid elements, or the angular growth (germination) of rod-shaped organisms. As yet, the mechanisms underlying each of these processes remain to be clarified.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 74 (1970), S. 292-300 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Beleuchtung im Mikroskop kann bei Bakterien, welche auf Nährbouillonagar in ihrer Entwicklung beobachtet werden, Wachstumshemmung, morphologische Veränderungen und Abtötung verursachen, auch wenn der Spektralbereich auf das Sichtbare begrenzt ist. Verschiedene Bakterien unterscheiden sich in ihrer Empfindlichkeit. Nicht nur Photoinaktivierung, sondern auch Erwärmung infolge absorbierter Strahlungsenergie kann zu den Folgen beitragen; Benzalaceton in Wasser schmilzt unter Beleuchtung im Mikroskop bei einer Umgebungstemperatur, welche 15°C unter derjenigen des Schmelzpunktes liegt. Maßnahmen zur Verringerung der Beleuchtungseinflüsse werden besprochen.
    Notes: Summary Microscope illumination can cause retardation of growth, morphological alterations, and death of bacteria on nutrient agar in microscope growth chambers, even if the radiation is limited to the visible range of the spectrum. Various bacteria differ from one another in their sensitivity to microscope illumination. Not only photoinactivation but also a rise in temperature may contribute to these effects, as shown by the melting of benzalacetone in the illuminated field of an aqueous mount at an ambient temperature at least 15 degrees below its M. P. Recommendations are presented for reducing the effects of microscope illumination in developmental studies.
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  • 7
    ISSN: 1365-2230
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We report a case of vulval squamous cell carcinoma (SCC) arising in chronic hidradenitis suppurativa (HS). The patient had a complex medical history including a 25-year-history of Crohn's disease. In addition she had recently received immunosuppressive therapy for nephrotic syndrome secondary to membranous glomerulonephritis. A painful nodule was noted on the vulva that was clinically very suspicious of SCC. An excision biopsy confirmed the diagnosis. There are few publications in the English literature citing association between HS and the development of SCC. The first report in the English literature of vulval SCC arising in chronic HS was published in 1999. We wish to draw attention to the possibility that patients with HS may develop SCC in lesional skin. A painful lump or ulcer could easily be mistaken for an inflammatory lesion and a low threshold for biopsy is warranted. We suggest constant vigilance with regard to malignant change in ano-genital HS as the diagnosis can be difficult.
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    ISSN: 1365-2230
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Scleroderma has been associated with exposure to many substances in the past ranging from vinyl chloride to silicon dioxide. In recent years there have been a number of case reports linking modern chemotherapy agents, such as the taxanes to the development of scleroderma like changes. We present a further case of scleroderma in association with chemotherapy but question the role of some of the agents previously implicated. A brief review of the current literature is included.
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  • 9
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
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  • 10
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Patients with chronic lymphoedema are prone to develop chronic infections and various tumours in the lymphoedematous limb, suggesting that regional immune surveillance is impaired. To test the hypothesis that cutaneous cell-mediated immunity is impaired. 35 women with postmastectomy lymphoedema were investigated using dinitrochlorobenzene to test the afferent and efferent loops of the allergic contact immune response. The results suppot the role of lymphatics as an important component of the immune response to allergens by the demonstration of impairment of both the afferent and efferent loops of the allergic contact dermatitis reaction, and confirm that there is suppression of immune competence in a lymphoedematous limb.
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