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Selective isolation and taxonomic analysis of the genus Micromonospora

Mexson, Joanne (2000) Selective isolation and taxonomic analysis of the genus Micromonospora. Doctor of Philosophy (PhD) thesis, University of Kent. (doi:10.22024/UniKent/01.02.86198) (KAR id:86198)


Micromonosporae were isolated from a diverse range of environmental habitats and geographic locations. The dispersion and differential centrifugation

technique, coupled with a phenol pre-treatment and the use of colloidal chitin and M3 agars as selective media proved to be highly efficient for the recovery of micromonosporae from environmental samples. The dispersion and centrifugation technique yielded recoveries of up to 10,000 fold more micromonosporae than the traditional vortex technique. Counts varied between 0 and 9 * 104 colony forming units/g for the terrestrial samples and from 6 to 5 * 102 colony forming units/g for the marine samples. The highest counts of micromonosporae (9 * 104 colony forming units/g) were recovered from a Namibian sample. A number of alkali tolerant micromonosporae were isolated from the Indonesian samples using the same procedure but with the medium adjusted to pH 10. Counts of alkalitolerant micromonosporae ranged from 0 to 5 * 103 colony forming units/g of sample, with the highest counts being recovered from a rice paddy field. Representative alkalitolerant micromonosporae grew well on media at pH 7 to 8. Pyrolysis mass spectrometry (PyMS) was used to rapidly screen representatives

of Micromonospora isolates from all environmental habitats and geographical locations sampled. PyMS revealed a number of pyro-groups containing isolates distinct from the Type strains suggesting that these isolates may represent novel

taxa. There was some evidence of isolates forming pyro-groups based on their sample location. One hundred and eighty representatives of the genus

micromonospora and 15 duplicated strains were examined for 134 unit characters and the resultant data analysed using the Jaccard (SJ) and simple matching SSM coefficients. Clustering was achieved using the unweighted pair group method with arithmetic averages algorithm (UPGMA). Good congruence was found between the classifications based on the SJ and SSM, UPGMA analyses. The numerical phenetic data were difficult to interpret but a measure of confidence can be placed in the numerical classification based on the SJ, UPGMA analysis given the acceptable cophenetic correlation and test error values and the congruence observed with the results from the SSM, UPGMA analysis. The test strains were assigned to major (4 or more strains), minor (2-3 strains) and single membered clusters defined at the 69% similarity level in the S], UPGMA classification. There was good agreement between the pyrogroups formed in the PyMS analyses and the clusters generated from the numerical taxonomy analysis. The PyMS and numerical taxonomic analyses revealed that there is some evidence for Micromonospora isolates existing as geovars as both techniques revealed some evidence for isolates grouping according to their sample location. Attempts to sequence the 16S gene of Micromonospora isolates were unsuccessful due to difficulties in obtaining high quantities of pure DNA and because questions have been raised over whether this genus contains more than one rRNA operon. The single strand conformation polymorphism (SSCP) technique demonstrated that differences in 16S rONA sequences between isolates could be detected and individual profiles for the isolates could be generated. The SSCP technique also highlighted the discrepancies that may exist between supposedly identical type strains in culture collections.

Item Type: Thesis (Doctor of Philosophy (PhD))
DOI/Identification number: 10.22024/UniKent/01.02.86198
Additional information: This thesis has been digitised by EThOS, the British Library digitisation service, for purposes of preservation and dissemination. It was uploaded to KAR on 09 February 2021 in order to hold its content and record within University of Kent systems. It is available Open Access using a Creative Commons Attribution, Non-commercial, No Derivatives ( licence so that the thesis and its author, can benefit from opportunities for increased readership and citation. This was done in line with University of Kent policies ( If you feel that your rights are compromised by open access to this thesis, or if you would like more information about its availability, please contact us at and we will seriously consider your claim under the terms of our Take-Down Policy (
Uncontrolled keywords: Micromonosporae; Centrifugation; Habitats
Subjects: Q Science > QR Microbiology
Divisions: Divisions > Division of Natural Sciences > Biosciences
SWORD Depositor: SWORD Copy
Depositing User: SWORD Copy
Date Deposited: 29 Oct 2019 16:34 UTC
Last Modified: 14 Feb 2022 12:49 UTC
Resource URI: (The current URI for this page, for reference purposes)

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