Exploring B vitamin biosynthesis and exchange in understudied marine stramenopiles and their communities
type: CreativeWork
description: Microbes are the dominant form of life on Earth. Environmental sequencing has revealed the extent of the diversity of microbial life in all environments, not least the ocean. In this vast aquatic environment microbes, both prokaryotic and eukaryotic, play essential roles in the cycling of nutrients, primary productivity and form the basis of all food webs. These single-celled organisms do not live in isolation, rather they form complex communities, a dominant feature of which is the exchange of nutrients. In many areas of the ocean the concentration of some macro and micronutrients are limiting to the growth of some organisms. In addition, many organisms appear to have dispensed with the ability to biosynthesise various micronutrients, for example, B vitamins. Instead, they rely on an external source to satisfy their requirement. Here I explore the role of B vitamin exchange in microbial communities, with a particular focus on the marine protists of the stramenopile group of eukaryotes. An initial investigation took environmental sea water samples and applied different B vitamin and macronutrient amendments to assess if any of these compounds were limiting for the growth of the microbial community as a whole in this area of the ocean (English Channel), or if growth was co-limited by both B vitamin and macronutrient concentration. The results suggested that none of the B vitamins tested were a limiting factor for growth of the majority of species, either prokaryotic or eukaryotic. However, some changes to the microbial assemblage were observed when assessing the relative transcriptional activities of the organisms in the samples. For example, the bacterial genus Litorivivens was more transcriptionally active (high ratio of ribosomal RNA reads to ribosomal DNA reads) under the addition of vitamins B2, B3, B5, B6 and B9. The eukaryotic genera Ostreococcus and Picochlorum were also more active in the same condition. The stramenopiles display considerable variety in morp…
abstract: Microbes are the dominant form of life on Earth. Environmental sequencing has revealed the extent of the diversity of microbial life in all environments, not least the ocean. In this vast aquatic environment microbes, both prokaryotic and eukaryotic, play essential roles in the cycling of nutrients, primary productivity and form the basis of all food webs. These single-celled organisms do not live in isolation, rather they form complex communities, a dominant feature of which is the exchange of nutrients. In many areas of the ocean the concentration of some macro and micronutrients are limiting to the growth of some organisms. In addition, many organisms appear to have dispensed with the ability to biosynthesise various micronutrients, for example, B vitamins. Instead, they rely on an external source to satisfy their requirement. Here I explore the role of B vitamin exchange in microbial communities, with a particular focus on the marine protists of the stramenopile group of eukaryotes. An initial investigation took environmental sea water samples and applied different B vitamin and macronutrient amendments to assess if any of these compounds were limiting for the growth of the microbial community as a whole in this area of the ocean (English Channel), or if growth was co-limited by both B vitamin and macronutrient concentration. The results suggested that none of the B vitamins tested were a limiting factor for growth of the majority of species, either prokaryotic or eukaryotic. However, some changes to the microbial assemblage were observed when assessing the relative transcriptional activities of the organisms in the samples. For example, the bacterial genus Litorivivens was more transcriptionally active (high ratio of ribosomal RNA reads to ribosomal DNA reads) under the addition of vitamins B2, B3, B5, B6 and B9. The eukaryotic genera Ostreococcus and Picochlorum were also more active in the same condition. The stramenopiles display considerable variety in morp…
author: Absolon, Dominic
language: eng
keywords: B vitamins, Metabolic pathways, Metagenomics, Microbial communities, Protists, Stramenopiles
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/367a141d-6123-4f17-ad9b-ad9df383d389/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2023-09-01
date modified: 2026-07-22T22:24:07Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.104222