The role of enteric bacteria in the Abalone, Haliotis Midae

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dc.contributor.advisorCook, Peteren_ZA
dc.contributor.advisorCoyne, Vernonen_ZA
dc.contributor.authorErasmus, Jean Helenen_ZA
dc.date.accessioned2016-03-21T19:14:06Z
dc.date.available2016-03-21T19:14:06Z
dc.date.issued1996en_ZA
dc.descriptionSummary in English.en_ZA
dc.description.abstractThe role of bacteria in the digestive tract of the abalone Haliotis midae was examined to determine whether bacteria aid hydrolysis of polysaccharides present in seaweeds which farmed abalone consume. The enteric bacteria were enumerated using culturable and total (DAPI) counts. The numbers of culturable bacteria fell between 3.5x10⁵ and 2.3x10⁸ cfu/g wet weight tissue. The DAPI counts were between 1.6x10⁹ and 5.1x10⁹ cells per gram of tissue. The numbers of bacteria differed between the crop, stomach and intestine. Electron microscopy showed that bacteria were present on the food and gut wall. No specialised structures, to aid adhesion of bacteria, were apparent on the gut wall. The isolated bacteria were identified to genus level using standard biochemical and morphological tests. The common genera identified were Vibrio, Alcaligenes, Flavobacteria, Pseudomonas and Aeromonas. The bacterial communities in each gut region varied, suggesting that both resident and transient bacterial populations are present in H. midae. Alcaligenes occurred mainly in the crop, while Vibrio species were predominant in the stomach and intestine. The bacterial isolates were tested for their ability to hydrolyse the polysaccharides alginate, laminarin, CMC, carrageenan and agarose. Bacteria able to utilise these polysaccharides belonged to the genera Flavobacteria, Pseudomonas, Vibrio, Alcaligenes, Bacillus and Enterobacteria. Many of the isolated bacteria were capable of utilising two or three of the substrates tested. Quantitative poly saccharase assays using the reducing sugar assays of Nelson (1944) and Somogyi (1952) and Gardner et al. (1988) were employed. These assays showed that bacteria from the crop exhibited the greatest degree of CMC and alginate hydrolysis. Bacteria from the intestine exhibited the greatest carrageenan and agarose hydrolysis. The endogenous enzymes produced by H. midae were examined using extracts of the hepatopancreas as it was found to be bacteria free. It was found that abalone synthesize a CMCase, laminarinase, alginase, carrageenanase and agarase. However, the synthesis of these enzymes was related to the diet of the abalone. Abalone fed Ecklonia (which contains relatively high concentrations of alginate and laminarin) exhibited significantly higher alginase and laminarinase activity than abalone fed Gracilaria. Similarly, abalone fed Gracilaria (which contains relatively high proportions of carrageenan and agar) produced significantly higher carrageenanase and agarase activity. Furthermore, these enzyme activities were found to be similar to those extracted from gnotobiotic abalone (obtained using the antibiotics chloramphenicol (250μg/ml), ampicillin (600μg/ml) and cefotaxime (250μg/ml)), indicating that polysaccharide synthesis occurs in the hepatopancreas of H. midae. Polysaccharase assays on gnotobiotic abalone were compared to assays on untreated abalone. Bacteria were found to significantly enhance the polysaccharase activity of alginase, laminarinase and agarase hydrolysis.en_ZA
dc.identifier.apacitationErasmus, J. H. (1996). <i>The role of enteric bacteria in the Abalone, Haliotis Midae</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. Retrieved from http://hdl.handle.net/11427/18062en_ZA
dc.identifier.chicagocitationErasmus, Jean Helen. <i>"The role of enteric bacteria in the Abalone, Haliotis Midae."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1996. http://hdl.handle.net/11427/18062en_ZA
dc.identifier.citationErasmus, J. 1996. The role of enteric bacteria in the Abalone, Haliotis Midae. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Erasmus, Jean Helen AB - The role of bacteria in the digestive tract of the abalone Haliotis midae was examined to determine whether bacteria aid hydrolysis of polysaccharides present in seaweeds which farmed abalone consume. The enteric bacteria were enumerated using culturable and total (DAPI) counts. The numbers of culturable bacteria fell between 3.5x10⁵ and 2.3x10⁸ cfu/g wet weight tissue. The DAPI counts were between 1.6x10⁹ and 5.1x10⁹ cells per gram of tissue. The numbers of bacteria differed between the crop, stomach and intestine. Electron microscopy showed that bacteria were present on the food and gut wall. No specialised structures, to aid adhesion of bacteria, were apparent on the gut wall. The isolated bacteria were identified to genus level using standard biochemical and morphological tests. The common genera identified were Vibrio, Alcaligenes, Flavobacteria, Pseudomonas and Aeromonas. The bacterial communities in each gut region varied, suggesting that both resident and transient bacterial populations are present in H. midae. Alcaligenes occurred mainly in the crop, while Vibrio species were predominant in the stomach and intestine. The bacterial isolates were tested for their ability to hydrolyse the polysaccharides alginate, laminarin, CMC, carrageenan and agarose. Bacteria able to utilise these polysaccharides belonged to the genera Flavobacteria, Pseudomonas, Vibrio, Alcaligenes, Bacillus and Enterobacteria. Many of the isolated bacteria were capable of utilising two or three of the substrates tested. Quantitative poly saccharase assays using the reducing sugar assays of Nelson (1944) and Somogyi (1952) and Gardner et al. (1988) were employed. These assays showed that bacteria from the crop exhibited the greatest degree of CMC and alginate hydrolysis. Bacteria from the intestine exhibited the greatest carrageenan and agarose hydrolysis. The endogenous enzymes produced by H. midae were examined using extracts of the hepatopancreas as it was found to be bacteria free. It was found that abalone synthesize a CMCase, laminarinase, alginase, carrageenanase and agarase. However, the synthesis of these enzymes was related to the diet of the abalone. Abalone fed Ecklonia (which contains relatively high concentrations of alginate and laminarin) exhibited significantly higher alginase and laminarinase activity than abalone fed Gracilaria. Similarly, abalone fed Gracilaria (which contains relatively high proportions of carrageenan and agar) produced significantly higher carrageenanase and agarase activity. Furthermore, these enzyme activities were found to be similar to those extracted from gnotobiotic abalone (obtained using the antibiotics chloramphenicol (250μg/ml), ampicillin (600μg/ml) and cefotaxime (250μg/ml)), indicating that polysaccharide synthesis occurs in the hepatopancreas of H. midae. Polysaccharase assays on gnotobiotic abalone were compared to assays on untreated abalone. Bacteria were found to significantly enhance the polysaccharase activity of alginase, laminarinase and agarase hydrolysis. DA - 1996 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1996 T1 - The role of enteric bacteria in the Abalone, Haliotis Midae TI - The role of enteric bacteria in the Abalone, Haliotis Midae UR - http://hdl.handle.net/11427/18062 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/18062
dc.identifier.vancouvercitationErasmus JH. The role of enteric bacteria in the Abalone, Haliotis Midae. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1996 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/18062en_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.otherMicrobiologyen_ZA
dc.subject.otherZoologyen_ZA
dc.titleThe role of enteric bacteria in the Abalone, Haliotis Midaeen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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