Studies on stationary phase Vibrio sp. 2

Simple item page
dc.contributor.advisorWoods, David Ren_ZA
dc.contributor.authorCar, Nicholas Georgeen_ZA
dc.date.accessioned2016-09-25T16:46:51Z
dc.date.available2016-09-25T16:46:51Z
dc.date.issued1987en_ZA
dc.description.abstractVibrio sp. 2 stationary phase cells are novel and interesting in that they are able to support phage growth in standing cultures, but not in shaken (aerated) cultures. Many physiological and morphological characteristics change when Vibrio sp. 2 stationary phase cells are removed from aeration: the relatively high levels of protein synthesis (Robb et al., 1977; 1978) decrease, with a concomitant increase in the levels of RNA synthesis; protein degradation rises from 1 %h⁻¹ to 2,9 %h⁻¹, and whilst the average cell length decreases, the range of cell lengths markedly increases. The magic spot nucleotides, ppGpp and pppGpp, which are present in stressed exponential phase Vibrio sp. 2 cells, are not detectable in stationary phase Vibrio cells. The specific proteolytic activity of shaking stationary phase cell-free extracts against the foreign protein [¹⁴C-me]globin was slightly higher than that of extracts from standing or exponential phase cells, while the specific proteolytic activity against [¹²⁵I]-insulin was slightly lower. On the basis of inhibitor studies and subcellular distribution, the proteolytic activities of the three types of extract differed. The addition of exogenous ATP to cell-free extracts either stimulated (Car & Woods, 1984) or depressed proteolytic activity depending on the procedure used to prepare the extracts. The proteolytic activity of fractions containing substantial amounts of membrane material, from all three types of extract, were markedly depressed by ATP. On preincubation of cell-free extracts from exponentially growing cells prior to assay of proteolytic activity, the activity was markedly stimulated (two- to four-fold). The stimulation,. however, varied, greatly between independently produced extracts. ATP had a much smaller stimulatory effect on preparations free of cell wall material from both types of stationary phase cells (the stimulation was less than two-fold), and the stimulation was not affected by preincubation of the extracts. Extracts prepared from starving cells, previously in exponential growth, were affected by the addition of ATP in a similar manner to that observed with stationary phase extracts (Car & Woods, 1984). Exponential and both types of stationary phase Vibrio sp. 2 cells have ATP-stimulated and ATP-depressed activities separable by ion-exchange chromatography, in addition to several other proteolytic activities. All types of Vibrio sp. 2 cells have a similar complement of proteolytic activities.en_ZA
dc.identifier.apacitationCar, N. G. (1987). <i>Studies on stationary phase Vibrio sp. 2</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. Retrieved from http://hdl.handle.net/11427/21894en_ZA
dc.identifier.chicagocitationCar, Nicholas George. <i>"Studies on stationary phase Vibrio sp. 2."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1987. http://hdl.handle.net/11427/21894en_ZA
dc.identifier.citationCar, N. 1987. Studies on stationary phase Vibrio sp. 2. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Car, Nicholas George AB - Vibrio sp. 2 stationary phase cells are novel and interesting in that they are able to support phage growth in standing cultures, but not in shaken (aerated) cultures. Many physiological and morphological characteristics change when Vibrio sp. 2 stationary phase cells are removed from aeration: the relatively high levels of protein synthesis (Robb et al., 1977; 1978) decrease, with a concomitant increase in the levels of RNA synthesis; protein degradation rises from 1 %h⁻¹ to 2,9 %h⁻¹, and whilst the average cell length decreases, the range of cell lengths markedly increases. The magic spot nucleotides, ppGpp and pppGpp, which are present in stressed exponential phase Vibrio sp. 2 cells, are not detectable in stationary phase Vibrio cells. The specific proteolytic activity of shaking stationary phase cell-free extracts against the foreign protein [¹⁴C-me]globin was slightly higher than that of extracts from standing or exponential phase cells, while the specific proteolytic activity against [¹²⁵I]-insulin was slightly lower. On the basis of inhibitor studies and subcellular distribution, the proteolytic activities of the three types of extract differed. The addition of exogenous ATP to cell-free extracts either stimulated (Car & Woods, 1984) or depressed proteolytic activity depending on the procedure used to prepare the extracts. The proteolytic activity of fractions containing substantial amounts of membrane material, from all three types of extract, were markedly depressed by ATP. On preincubation of cell-free extracts from exponentially growing cells prior to assay of proteolytic activity, the activity was markedly stimulated (two- to four-fold). The stimulation,. however, varied, greatly between independently produced extracts. ATP had a much smaller stimulatory effect on preparations free of cell wall material from both types of stationary phase cells (the stimulation was less than two-fold), and the stimulation was not affected by preincubation of the extracts. Extracts prepared from starving cells, previously in exponential growth, were affected by the addition of ATP in a similar manner to that observed with stationary phase extracts (Car & Woods, 1984). Exponential and both types of stationary phase Vibrio sp. 2 cells have ATP-stimulated and ATP-depressed activities separable by ion-exchange chromatography, in addition to several other proteolytic activities. All types of Vibrio sp. 2 cells have a similar complement of proteolytic activities. DA - 1987 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1987 T1 - Studies on stationary phase Vibrio sp. 2 TI - Studies on stationary phase Vibrio sp. 2 UR - http://hdl.handle.net/11427/21894 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/21894
dc.identifier.vancouvercitationCar NG. Studies on stationary phase Vibrio sp. 2. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1987 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/21894en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Molecular and Cell Biologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherBacteriophages.en_ZA
dc.subject.otherBacteriaen_ZA
dc.subject.otherMicrobiologyen_ZA
dc.titleStudies on stationary phase Vibrio sp. 2en_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_sci_1987_car_nicholas_george.pdf
Size:
2.76 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
PhD / Doctoral