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  • Hyphomicrobium  (2)
  • Antarctic cryptoendoliths  (1)
  • Cell wall composition  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 132 (1982), S. 96-99 
    ISSN: 1432-072X
    Keywords: Hyphomicrobium ; Continuous culture ; Synchronization technique ; Synchronous swarmer cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A technique was developed for synchronization ofHyphomicrobium sp. strain B-522. Bacteria were grown in continuous culture with methanol (0.1%; v/v) growth limiting. Vitamin B12 (2.5 μg/l) was necessary to obtain steady state growth. The critical dilution rate wasD c =0.112; maximum cell output occurred atD=0.105 (Dx=30 mg l-1 h-1). Continuous cultures ofHyphomicrobium B-522 atD=0.110 were used to obtain cells for synchronization experiments. Synchronization was achieved by trapping young hyphal and budding cells in a glass wool column, while the initial swarmer cells were allowed to pass through. By semicontinuously rinsing the system, newly produced swarmers could be sampled in the effluent. The mean length of these synchronous swarmer cells was 1.25 μm (s=±0.13 μm; range 0,6 μm) as compared to 1.40 μm (s=±0.21 μm; range 1.2 μm) for swarmer cells of the continuous culture. Division of synchronous swarmer populations was completed after 7 h; the synchronization index was 0.76.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 131 (1982), S. 32-35 
    ISSN: 1432-072X
    Keywords: Hyphomicrobium ; Growth requirements ; Growth improvement ; Vitamin B12 ; C-1 utilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth yields and rates of 3 hyphomicrobia were improved by varying components of or adding compounds to medium 337. Methanol (0.5% v/v), and similarly methylamine·HCl (3.38g/l), were optimal among 22 C-sources tested; increasing the methylamine·HCl concentration to 5.07g/l gave higher Hyphomicrobium B-522 yields but also prolonged lag periods. Ten C-sources (organic acids, alcohols) stimulated growth slightly but significantly, even in subcultures. Sugar compounds were not utilized. Strains B-522 and ZV-580 were stimulated by l-lysine and gluconate, while NQ-521 gr was stimulated by aspartate. N-Sources tested were inorganic (3), organic (3), or complex (3). (NH4)2SO4 (0.5g/l) was optimal for strains ZV-580 and NQ-521 gr, but Hyphomicrobium B-522 grew best with urea-N. With NH 4 + , strain B-522 grew as homogeneous suspension, all other N-sources caused clumping and pellicle formation. Inorganic requirements (PO 4 3- , Mg, Ca, Fe, Mn, Mo) of strains B-522 and ZV-580 were optimized. Addition of Ni, Co, or Zn had no effect; metals “44” or Cu, resulted in growth inhibition. Vitamin B12 stimulated Hyphomicrobium B-522; 2.5μg/l B12 decreased the doubling time from 9.3–10.8h to 5.4–5.8h. All combined single improvements resulted in a protein increase of 557% (B-522), 141% (NQ-521 gr), or 109% (ZV-580), respectively.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 138 (1984), S. 200-205 
    ISSN: 1432-072X
    Keywords: Budding bacteria ; Cell wall composition ; Antibiotic resistance ; Murein ; Taxonomy of eubacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Seven strains of budding, non-prosthecate bacteria belonging to the Planctomyces/Pasteuria group and a Prosthecomicrobium sp. were examined for muramic and diaminopimelic acids. These typical components of Gram-negative murein were found only in Prosthecomicrobium strain IFAM 1314, but they could not be detected in seven budding bacteria. Electron micrographs of ultrathin cell wall sections of strains IFAM 1313 and 1317 showed a membrane with bilayer structure outside the cytoplasmic membrane. 10% sodium dodecylsulfate treatment (30 min, 100°C) allowed the isolation of highly stable cell sacculi which, upon chemical analysis, proved to be mainly proteinaceous. The budding bacteria also showed considerable resistance against penicillin G, ampicillin, cephalotin and D-cycloserin. Our data indicate that these bacteria lack an ordinary Gram-negative type of murein and, instead, carry a stable protein envelope.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-9710
    Keywords: Antarctic cryptoendoliths ; biodiversity ; interactions ; plasmid transfer ; heavy metal resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Cryptoendolithic microorganisms from stratified communities in Antarctic sandstone were studied for physiological diversity and possible interactions. Cultures of 25 bacteria, five fungi, and two green algae from one boulder grew with a wide variety of organic carbon or nitrogen sources, they exhibited varied exoenzymatic activities and were psychrophilic or psychrotrophic. Many isolates excreted vitamins into the medium and were stimulated by other vitamins. Organic acid excretion and siderophore formation were common, but antibiotic activity was rare. Plasmids were found in 24% of the bacteria, and many of these strains showed resistance to antibiotics and heavy metals. A small plasmid (2.9 kb) from strain AA-341 was electrotransferred into sensitive isolates, thereby rendering these resistant to amplicillin and Cr3+ Bacterial cultures in spent algal medium and coculture with algae demonstrated beneficial (rarely inhibitory) interactions. A search for free organic compounds in zones of the sandstone community revealed sugars, sugar alcohols, organic acids and amino acids-in many cases the same compounds that were excreted into the laboratory medium. Data presented here indicate low taxonomic but high physiological diversity among these heterotrophic cryptoendoliths. This physiological diversity, as well as the spatial separation in layers with distinct activities, allows coexistence within the community and contributes to the stability of this ecosystem.
    Type of Medium: Electronic Resource
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