title: Photobiont selectivity for lichens and evidence for a possible glacial refugium in the Ross Sea Region, Antarctica

authors: Jones, Tracey C.

subjects: algae

abstract: Lichens are a symbiosis consisting of heterotrophic, fungal (mycobiont) and photosynthetic algal or cyanobacterial (photobiont) components. We examined photobiont sequences from lichens in the Ross Sea Region of Antarctica using the internal transcribed spacer region of ribosomal DNA and tested the hypothesis that lichens from this extreme environment would demonstrate low selectivity in their choice of photobionts. Sequence data from three targeted lichen species (Buellia frigida, Umbilicaria aprina and Umbilicaria decussata) showed that all three were associated with a common algal haplotype (an unnamed Trebouxia species) which was present in all taxa and at all sites, suggesting lower selectivity. However, there was also association with unique, local photobionts as well as evidence for species-specific selection. For example, the cosmopolitan U. decussata was associated with two photobiont species, Trebouxia jamesii and an unnamed species. The most commonly collected lichen (B. frigida) had its highest photobiont haplotype diversity in the Dry Valley region, which may have served as a refugium during glacial periods. We conclude that even in these extreme environments, photobiont selectivity still has an influence on the successful colonisation of lichens. However, the level of selectivity is variable among species and may be related to the ability of some (e.g. B. frigida) to colonise a wider range of habitats.

text: Photobiont selectivity for lichens and evidence for a possible glacial refugium in the Ross Sea Region, Antarctica Lichens are a symbiosis consisting of heterotrophic, fungal (mycobiont) and photosynthetic algal or cyanobacterial (photobiont) components. We examined photobiont sequences from lichens in the Ross Sea Region of Antarctica using the internal transcribed spacer region of ribosomal DNA and tested the hypothesis that lichens from this extreme environment would demonstrate low selectivity in their choice of photobionts. Sequence data from three targeted lichen species (Buellia frigida, Umbilicaria aprina and Umbilicaria decussata) showed that all three were associated with a common algal haplotype (an unnamed Trebouxia species) which was present in all taxa and at all sites, suggesting lower selectivity. However, there was also association with unique, local photobionts as well as evidence for species-specific selection. For example, the cosmopolitan U. decussata was associated with two photobiont species, Trebouxia jamesii and an unnamed species. The most commonly collected lichen (B. frigida) had its highest photobiont haplotype diversity in the Dry Valley region, which may have served as a refugium during glacial periods. We conclude that even in these extreme environments, photobiont selectivity still has an influence on the successful colonisation of lichens. However, the level of selectivity is variable among species and may be related to the ability of some (e.g. B. frigida) to colonise a wider range of habitats.

year: 2013

title: An investigation of a Mollicute-like organism inhabiting the human gastrointestinal tract

authors: Care, Andrew Shane

subjects: Mollicute

abstract: The microflora inhabiting the human gastrointestinal tract can be considered an essential 'metabolic organ', in a symbiotic relationship with its host. Due to the low cultivability and inappropriate sampling methodology the microflora is poorly explored and ill-defined. 

Preliminary, molecular-based research at the University of Waikato revealed the presence of 16S rRNA gene sequences originating from novel Mollicute-like species inhabiting the human GI tract. A ~830bp 'consensus' sequence representing these novel Mollicute-like sequences was classified within the Mollicute Genus Anaeroplasma the type species of which is Anaeroplasma abactoclasticum. It also displayed near exact matches with 16S rRNA sequences obtained from the human GI tract and matches of high similarity to those from the mouse GI tract in the NCBI database.

This thesis describes an attempt to design and create primers that would amplify and characterize full-length versions of these Mollicute-like sequences from samples obtained from the mucosal surface of the human gastrointestinal tract. Primers sets targeted extended 5' and 3' versions of these novel 'known' sequences and were designed from sequence matches found in the preliminary work and other related sequences from the NCBI database.

The attempt to amplify a full-length version of these novel Mollicute-like sequences was proven to be unsuccessful. No sequences were classified within the Genus Anaeroplasma, although 81% of amplicons from the 5' extending primer sets were classified within the same division as the Mollicutes, the Firmicutes, only 6% of the sequenced amplicons from the 3' extending primer set belonged to this division. Phylograms containing these 'relevant' sequences and the 'consensus' sequence grouped the 'consensus' sequence separately, indicating a lower relatedness than would have been seen if any of the amplicons contained the 'consensus' sequence.

text: An investigation of a Mollicute-like organism inhabiting the human gastrointestinal tract The microflora inhabiting the human gastrointestinal tract can be considered an essential 'metabolic organ', in a symbiotic relationship with its host. Due to the low cultivability and inappropriate sampling methodology the microflora is poorly explored and ill-defined. 

Preliminary, molecular-based research at the University of Waikato revealed the presence of 16S rRNA gene sequences originating from novel Mollicute-like species inhabiting the human GI tract. A ~830bp 'consensus' sequence representing these novel Mollicute-like sequences was classified within the Mollicute Genus Anaeroplasma the type species of which is Anaeroplasma abactoclasticum. It also displayed near exact matches with 16S rRNA sequences obtained from the human GI tract and matches of high similarity to those from the mouse GI tract in the NCBI database.

This thesis describes an attempt to design and create primers that would amplify and characterize full-length versions of these Mollicute-like sequences from samples obtained from the mucosal surface of the human gastrointestinal tract. Primers sets targeted extended 5' and 3' versions of these novel 'known' sequences and were designed from sequence matches found in the preliminary work and other related sequences from the NCBI database.

The attempt to amplify a full-length version of these novel Mollicute-like sequences was proven to be unsuccessful. No sequences were classified within the Genus Anaeroplasma, although 81% of amplicons from the 5' extending primer sets were classified within the same division as the Mollicutes, the Firmicutes, only 6% of the sequenced amplicons from the 3' extending primer set belonged to this division. Phylograms containing these 'relevant' sequences and the 'consensus' sequence grouped the 'consensus' sequence separately, indicating a lower relatedness than would have been seen if any of the amplicons contained the 'consensus' sequence.

year: 2009

title: Overcoming ‘Being’ in Favour of Knowledge: The fixing effect of ‘mātauranga’

authors: Mika, Carl Te Hira

subjects: knowledge

abstract: It is common to hear Māori discuss primordial states of Being, yet in colonisation those very central beliefs are forced into weaker utterances. In this process those utterances merely conform to a colonised agenda. ‘Mātauranga’, a tidy term that overwhelmingly refers to an epistemological knowing of the world, colludes nicely with its English equivalent, ‘knowledge’, to further colonise those core contemplations of Being. Its plausibility relies on an orderly regard of things in the world. In education, historical and current practices of schooling pave the way for things in the world so that they amount to mātauranga for Māori, and even the term ‘ako’ will conspire in its own way. Both Novalis and Heidegger have the ability to identify subtly colonising philosophies, and may even propose some theoretical solutions for Māori.

text: Overcoming ‘Being’ in Favour of Knowledge: The fixing effect of ‘mātauranga’ It is common to hear Māori discuss primordial states of Being, yet in colonisation those very central beliefs are forced into weaker utterances. In this process those utterances merely conform to a colonised agenda. ‘Mātauranga’, a tidy term that overwhelmingly refers to an epistemological knowing of the world, colludes nicely with its English equivalent, ‘knowledge’, to further colonise those core contemplations of Being. Its plausibility relies on an orderly regard of things in the world. In education, historical and current practices of schooling pave the way for things in the world so that they amount to mātauranga for Māori, and even the term ‘ako’ will conspire in its own way. Both Novalis and Heidegger have the ability to identify subtly colonising philosophies, and may even propose some theoretical solutions for Māori.

year: 2012