摘要:

Ultrastructural, biochemical and genetic evidence has shown that the flagella and flagellin proteins from members of the archaea are distinct from their bacterial counterparts. The most important evidence is the sequence dissimilarity between archaeal and bacterial flagellins. We report here similarity between archaeal flagellins and members of the bacterial type IV pilin – transport superfamily. In addition to sequence similarity, the archaeal flagellins and the type IV pilin – transport superfamily share an unusual signal sequence cleavage site and may have functional parallels. This relationship has important implications for the assembly and biogenesis of archaeal flagella.Key words: flagellin, type IV pilin, homology, general secretion proteins, archaea.

ISSN:0008-4166    

DOI:10.1139/m94-011

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

The quantitative variation in the microflora in bottled mineral waters stored in polyvinyl chloride bottles was studied immediately after bottling and after 7 days storage, over 9 months. The microflora was determined by combining total counts using ethidium bromide, and the number of iodonitrophenyltetrazolium (INT)-positive cells determined with heterotrophic plate counts on R2A for prolonged incubation periods at 22 and 37 °C. Immediately after bottling of mineral water A, the total counts with ethidium bromide varied between 70.0 and 495.0 bacteria/mL. The number of INT-positive bacteria varied between 14.0 and 40.0% counts. The heterotrophic plate counts were higher at 22 °C than at 37 °C and varied between 1.1 and 13.2% and between 0.7 and 9.3% of the total counts, respectively. After 7 days storage, total bacterial counts increased by 1000 times, indicating multiplication of bacteria that were present in low numbers immediately after bottling. The percentage of INT-positive bacteria remained between 2.6 and 39.0% of the total counts but the number of culturable bacteria was higher than the number of INT-positive cells. Similar counts were found in other mineral waters (B, C, and D), but the numbers of INT-positive cells in two of them (B and D) were higher than the heterotrophic plate counts at 22 °C. These results show the presence in the aquifer and (or) bottling system of a flora that is neither INT-positive nor culturable and reinforce previous results that still mineral waters have a large bacterial population after storage.Key words: mineral water, bacterial populations, ethidium bromide, INT, HPC.

ISSN:0008-4166    

DOI:10.1139/m94-012

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

Adhesion ofCandida albicansgerm tubes to murine tissues was examined. An ex vivo assay previously employed to examine adhesion of yeast cells ofC.albicanswas adapted for use with germ tubes. Binding of germ tubes to kidney, liver, spleen, and lymph node tissues was found to occur throughout the tissue section, with little tissue morphologic specificity. In general, more organisms adhered to spleen and lymph node tissues than to kidney and liver tissues. Observation of adhesion with scanning electron microscopy showed three germ tube – tissue interactions described as loose, tight, or embedded.Key words:Candida, germ tubes, adhesion, ex vivo.

ISSN:0008-4166    

DOI:10.1139/m94-013

出版商:NRC Research Press    

年代:1994

数据来源: NRC