Ecology of Intertidal Microorganisms and Multivariate Analysis of Antibiotic and Heavy Metal Susceptibility of Deep-Sea Bacteria

El-Ghazzewi-Eddeb, Farage H (1988) Ecology of Intertidal Microorganisms and Multivariate Analysis of Antibiotic and Heavy Metal Susceptibility of Deep-Sea Bacteria. PhD thesis, University of Glasgow.

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Abstract

Deep-sea bacterial isolates from 5 sites in the N. E. Atlantic have been classified on the basis of their ability to grow in metal and antibiotic containing media at various concentrations, using a replica plating technique. The minimum inhibitory concentrations of antimicrobial agents for bacteria were determined and data submitted to cluster analysis. Cluster analysis was applied to split up a total of 843 deep-sea isolates into a number of groups depending on their antibiotic and metal salt resistance. Boundary lines were drawn across the dendrogram at different similarity levels and a number of groups were obtained. All groups clustered at or above 72% similarity level were drawn as a shaded triangles in my final diagram of the cluster analysis. The distance measure used in cluster analysis was the Euclidean distance squared. It was also transformed into percentage similarity (%S). The maximum number of isolates (107) occurred in cluster 12, while the minimum number (11) occurred in cluster 11. Only 1/3 of the clusters contained isolates from all the sampling sites. The number of isolates in each of the groups between sites and between depths was compared. Significant correlations were found between sites 2 and 4 and between sites 4 and 5. However, a large number of significant correlations were found between the sampling depths. A total of 561 isolates were obtained from the sediment samples in contrast to 143 and 139 isolates from burrow linings and faecal pellets respectively. The difference between the number of isolates/group in sediment, burrow linings and faecal pellets was analysed. A highly significant variation was found. 11 of the 21 clusters could be presumptively identified as they clustered with the reference cultures used. Cluster analysis was also applied to antibiotics alone (7 variables), to the heavy metals alone (6 variables) and to the antibiotics and heavy metals together (13 variables). The results showed that antibiotics classified into two distinct clusters due to their mode of action on Gram-positive or Gram-negative bacteria. Heavy metals calssified into one distinct cluster based on the mode of action on bacterial cell. Clustering of antibiotics and heavy metals together showed three distinct clusters and metal resistance was associated with the resistance to antibiotics. A bacteriological survey of Ardmore Point (Clyde Estuary) has been carried out over a period of 13 months. Samples have been taken monthly using a coring technique. Heterotrophic bacterial, fungal and yeast counts have been made on different media using the spread-plating method. API ZYM test-kits have been applied to intertidal sediments from Ardmore in an attempt to classify them biochemically by their enzyme reactions. API 20 E and API 20 NE have been applied to marine and non-marine isolates in order to test their accuracy in identifying marine bacteria.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Ecology, Biological oceanography
Date of Award: 1988
Depositing User: Enlighten Team
Unique ID: glathesis:1988-77657
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 14 Jan 2020 11:53
Last Modified: 14 Jan 2020 11:53
URI: http://theses.gla.ac.uk/id/eprint/77657

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