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Summary Since isolation of the Acetobacter strains responsible for ethanol oxidation in high acid, submerged vinegar fermentations is still extremely difficult, characterization of the vinegar microflora was approached by isolation and gel electrophoresis of plasmids extractable from the harvested microorganisms. Distinct plasmid profiles have been detected in all of 19 investigated fermenters from 5 different locations. Plasmid sizes varied between 1.3 and 133 Megadalton. Between 3 and 11 different plasmids were recognized in particular profiles. Comparison of these profiles from different sources proves that the plasmid profile of a vinegar fermenter is a unique property of the inherent microflora which allows definite conclusions regarding its stability, origin, identity and composition. 相似文献
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The relationship between ultrastructure and photosensitivity of pigmented neurons of the abdominal ganglion of Aplysia californica was investigated using electron microscopy and electrophysiological methods. Four identified neurons of similar light microscopic appearance were examined; two are photoresponsive and two are not. Illumination hyperpolarizes both responsive neurons. One of them, R2, requires roughly 100 times greater light intensities than does the other, the ventral photoresponsive neuron (VPN), for similar responses. Two neurons lying adjacent to VPN and similar in appearance to VPN do not have measurable electrophysiological responses to even the highest light intensities. All four neurons contained lipochondria, pigmented organelles associated with the light response. Therefore the presence of these organelles is not the only requirement for light sensitivity in these neurons. Illumination appeared to increase the number of membranous lipochondria in both R2 and the ventral neurons, but only in R2 was this increase significant. Factors such as the concentration of lipochondria near the plasma membrane may affect quantitative aspects of the light response, but in the insensitive cells the lipochondria are apparently uncoupled from other factors required for the light response. 相似文献
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Plant cell wall degrading enzymes (PCWDE) are the major virulence determinants in phytopathogenic Pectobacterium, and their production is controlled by many regulatory factors. In this study, we focus on the role of the AepA protein,
which was previously described to be a global regulator of PCWDE production in Pectobacterium carotovorum (Murata et al. in Mol Plant Microbe Interact 4:239–246, 1991). Our results show that neither inactivation nor overexpression of aepA affects PCWDE production in either Pectobacterium atrosepticum SCRI1043 or Pectobacterium carotovorum subsp. carotovorum SCC3193. The previously published observation based on the overexpression of aepA could be explained by the presence of the adjacent regulatory rsmB gene in the constructs used. Our database searches indicated that AepA belongs to the YtcJ subfamily of amidohydrolases.
YtcJ-like amidohydrolases are present in bacteria, archaea, plants and some fungi. Although AepA has 28% identity with the
formamide deformylase NfdA in Arthrobacter pascens F164, AepA was unable to catalyze the degradation of NdfA-specific N-substituted formamides. We conclude that AepA is a putative
aminohydrolase not involved in regulation of PCWDE production. 相似文献
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