Electronic Theses and Dissertations

Date of Award

1-1-2023

Document Type

Dissertation

Degree Name

Ph.D. in Biological Science

First Advisor

Erik F.Y. Hom

Second Advisor

Jason Hoeksema

Third Advisor

Patrick Curtis

Relational Format

dissertation/thesis

Abstract

In chapter 1, we describe a biosynthetic gene cluster responsible for making Dolastatin-10 (Dol-10), a historically important broad-spectrum anticancer agent discovered over 35 years ago. Encoded by the marine cyanobacterium Roseofilum reptotaenium, laboratory cultures of R. reptotaenium were found to produce a suite of Dol-10-related compounds that include monomethyl auristatin D (MMAD), a compound closely related to cytotoxic payload molecules commonly used as components of antibody drug-conjugates for targeted cancer therapy. Given R. reptotaenium’s association with black band disease (BBD), a serious threat to corals worldwide, the role of Dol-10 and its secreted analogues may need to be evaluated with respect to the chemical ecology of coral systems and the etiology of BBD.

In chapter 2, We present a dataset of 6 whole community shotgun metagenomic sequencing efforts for light cyanobacterial/algal crusts (LAC) and cyano lichen (CLC) biological soil crust types that have been sampled at the ecotone of the Mojave and Colorado Deserts in California. The eukaryotic kingdom is more predominant in CLC than LAC, though we don't have enough contigs to reconstruct any eukaryotic genome. LAC has higher bacterial diversity than CLC, with 73 distinct species compared to 33 species. There are 23 shared species found in both biocrust types. Additionally, LAC contains 12 cyanobacterial species rather than 5 species in CLC. Microcoleus sp. PCC 7113 is the most widespread taxa in both LAC and CLC. Lastly, Micromonosporaceae sp., a filamentous bacterial strain, is the most abundant organism in CLC, but absent from LAC.

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