title: The characterisation of three hyperthermophilic archaea from New Zealand hot springs

authors: Götz, Dorothee Klara

abstract: Archaea are a unique group of microorganisms that have been isolated from extreme environments such as geothermally active areas, highly saline habitats and extremely acidic sediments. Their capacity to withstand extreme conditions, and even thrive under them, makes them interesting objects of research.

The aim of this research was to isolate and characterise a variety of hyperthermophilic archaea from New Zealand hot springs. Three organisms were chosen for investigation. The coccoid isolate Wai21.S1 is a novel strain of the genus Thermococcus that was isolated from a hot spring at Waimangu Volcanic Valley. It is only the second described fresh-water isolate of this genus. Wai21.S1 is strictly anaerobic and strictly heterotrophic. The preferred carbon sources are starch, amylose and amylopectin. Elemental sulfur is not required and its presence does not enhance growth. There is no dependence on sodium chloride. Wai21.S1 grows optimally at 89°C and at pH 5.9. The 16S rRNA gene sequence shows a close relationship to T. zilligii. Wai21.S1 is proposed to be the type strain of a new species Thermococcus waimanguensis.

The isolate Tok2 was found in a sample from a hangi pool at Tokaanu, Turangi and was obtained from an enrichment culture containing konjac glucomannan as carbon source. Tok2 belongs to the genus Pyrobaculum. It is a strictly anaerobic organism which growths mainly heterotrophically on yeast extract and tryptone. Autotrophic growth was observed on CO₂/H₂ with thiosulfate or elemental sulfur as electron acceptor. Tok2 is rod-shaped with spherical bodies frequently observed at one or both ends, and the centre of the cells. Branched cells were occasionally observed. Tok2 grows optimally at 93°C and can grow up to 101°C. The optimum pH is 6.7. Tok2 is capable of reducing nitrate. The 16S rRNA gene sequence shows the close relationship of Tok2 to two other Pyrobaculum-like isolates from Tikitere, New Zealand the preliminarily named “Pyrobaculum neutrophilus” and strain IsoX. Phylogenetic data suggests that the three New Zealand isolates are strains of Pyrobaculum organotrophum despite strong physiological evidence against it. Further studies will be carried out to clarify the taxonomy of the New Zealand Pyrobaculum strains.

Tok1, a second organism found in the same enrichments culture as Tok2, could not be isolated and was therefore maintained in a consortium together with Tok2. Tok1 is a regular coccus which grows heterotrophically on glucomannan as sole carbon source. It is microaerotolerant and grows optimally at 98°C. The optimum pH is 7.3. Strain Tok1 is highly sensitive to yeast extract and sensitive to elemental sulfur. The 16S rRNA gene sequence which was obtained by cloning, shows that Tok1 is a member of the kingdom Crenarchaeota and is a representative of a novel genus. Phylogenetically strain Tok1 is positioned at the base of the order “Igneococcales”. Since strain Tok1 could not be purified, the novel species had to be described as a candidatus. The name Candidatus “Igneosphaera vetusta” was proposed.

The enzyme responsible for the degradation of konjac glucomannan was characterised and partially purified. The β-endomannanase was produced by strain Tok1 and is extremely thermostable. It shows highest activity around 110°C and is still enzymatically active at 120°C. The optimum pH for activity was at 6. Besides the mannanolytic activity, it exhibits a low xylanase activity. The enzyme is cell wall bound and no activity was found in the culture supernatant.

text: The characterisation of three hyperthermophilic archaea from New Zealand hot springs Archaea are a unique group of microorganisms that have been isolated from extreme environments such as geothermally active areas, highly saline habitats and extremely acidic sediments. Their capacity to withstand extreme conditions, and even thrive under them, makes them interesting objects of research.

The aim of this research was to isolate and characterise a variety of hyperthermophilic archaea from New Zealand hot springs. Three organisms were chosen for investigation. The coccoid isolate Wai21.S1 is a novel strain of the genus Thermococcus that was isolated from a hot spring at Waimangu Volcanic Valley. It is only the second described fresh-water isolate of this genus. Wai21.S1 is strictly anaerobic and strictly heterotrophic. The preferred carbon sources are starch, amylose and amylopectin. Elemental sulfur is not required and its presence does not enhance growth. There is no dependence on sodium chloride. Wai21.S1 grows optimally at 89°C and at pH 5.9. The 16S rRNA gene sequence shows a close relationship to T. zilligii. Wai21.S1 is proposed to be the type strain of a new species Thermococcus waimanguensis.

The isolate Tok2 was found in a sample from a hangi pool at Tokaanu, Turangi and was obtained from an enrichment culture containing konjac glucomannan as carbon source. Tok2 belongs to the genus Pyrobaculum. It is a strictly anaerobic organism which growths mainly heterotrophically on yeast extract and tryptone. Autotrophic growth was observed on CO₂/H₂ with thiosulfate or elemental sulfur as electron acceptor. Tok2 is rod-shaped with spherical bodies frequently observed at one or both ends, and the centre of the cells. Branched cells were occasionally observed. Tok2 grows optimally at 93°C and can grow up to 101°C. The optimum pH is 6.7. Tok2 is capable of reducing nitrate. The 16S rRNA gene sequence shows the close relationship of Tok2 to two other Pyrobaculum-like isolates from Tikitere, New Zealand the preliminarily named “Pyrobaculum neutrophilus” and strain IsoX. Phylogenetic data suggests that the three New Zealand isolates are strains of Pyrobaculum organotrophum despite strong physiological evidence against it. Further studies will be carried out to clarify the taxonomy of the New Zealand Pyrobaculum strains.

Tok1, a second organism found in the same enrichments culture as Tok2, could not be isolated and was therefore maintained in a consortium together with Tok2. Tok1 is a regular coccus which grows heterotrophically on glucomannan as sole carbon source. It is microaerotolerant and grows optimally at 98°C. The optimum pH is 7.3. Strain Tok1 is highly sensitive to yeast extract and sensitive to elemental sulfur. The 16S rRNA gene sequence which was obtained by cloning, shows that Tok1 is a member of the kingdom Crenarchaeota and is a representative of a novel genus. Phylogenetically strain Tok1 is positioned at the base of the order “Igneococcales”. Since strain Tok1 could not be purified, the novel species had to be described as a candidatus. The name Candidatus “Igneosphaera vetusta” was proposed.

The enzyme responsible for the degradation of konjac glucomannan was characterised and partially purified. The β-endomannanase was produced by strain Tok1 and is extremely thermostable. It shows highest activity around 110°C and is still enzymatically active at 120°C. The optimum pH for activity was at 6. Besides the mannanolytic activity, it exhibits a low xylanase activity. The enzyme is cell wall bound and no activity was found in the culture supernatant.

year: 1998

title: Using panel data to exactly estimate under-reporting by the self-employed

authors: Kim, Bonggeun

subjects: Engle curve

abstract: The income of the self-employed is often assumed to be understated in economic statistics. Debate exists about the extent of under-reporting and the resulting measures of the size of the underground economy. This paper refines a method developed by Pissarides and Weber (1989) and uses discrepancies between food shares and reported incomes to estimate under-reporting by the self-employed. In contrast to previous studies our panel data methodology distinguishes income under-reporting from transitory income fluctuations of the self-employed, and provides an exact estimate of the degree of under-reporting rather than just an interval estimate. Using panel data from Korea and Russia we estimate that 38 percent of the income of self-employed households in Korea and 47 percent of the income of Russian self-employed households is not reported.

text: Using panel data to exactly estimate under-reporting by the self-employed The income of the self-employed is often assumed to be understated in economic statistics. Debate exists about the extent of under-reporting and the resulting measures of the size of the underground economy. This paper refines a method developed by Pissarides and Weber (1989) and uses discrepancies between food shares and reported incomes to estimate under-reporting by the self-employed. In contrast to previous studies our panel data methodology distinguishes income under-reporting from transitory income fluctuations of the self-employed, and provides an exact estimate of the degree of under-reporting rather than just an interval estimate. Using panel data from Korea and Russia we estimate that 38 percent of the income of self-employed households in Korea and 47 percent of the income of Russian self-employed households is not reported.

year: 2008-10

title: Te Reo Tātai: The Development of a Mathematics Register for Māori-Medium Schooling

authors: Trinick, Anthony

subjects: Indigenous Mathematics education

abstract: This thesis investigates the development of a lexicon and register to facilitate the teaching of mathematics in the medium of te reo Māori. This sociolinguistic development is situated within the wider Māori language revitalisation movement in Aotearoa/New Zealand, of which Māori-medium education is a central component. 
Lexication of a language is a subdomain of corpus planning. Corpus, status and language-in-education planning are considered the three major interconnected domains of language planning and policy (LPP). For decades, the primary focus of LPP research has been on the activities of states and their agencies at the macro (national) level. The significance of this study is that it addresses this gap in the research, by investigating the development of LPP at the meso/micro-level—in this case, with respect to the development of a mathematics register for an endangered indigenous language, te reo Māori.
The thesis draws on two major participant data sources. The first is the narratives of key individuals at the forefront of lexical development for Māori-medium mathematics who recounted their experiences. The second is interviews with principals and teachers from two Māori-medium case study schools to examine their own learning and usage of the standardised pāngarau lexicon.
Two complementary theoretical frameworks were used to investigate the topic. First, an LPP theoretical framework was applied to investigate the complex relationships between the various levels of LPP that have impacted on the evolution of te reo Māori and Māori-medium schooling. Second, a linguistic framework, systemic functional linguistics (SFL), was used to investigate the linguistic and pedagogical issues.
Thesis findings show that the status of te reo Māori was variously affected by linguistic ideologies such as assimilation, which in turn led to such policies as English only in schooling. As a consequence, at the micro-level of LPP, Māori-medium mathematics development went into a hiatus for over 100 years, and at the macro-level, considerable language shift occurred to English, causing te reo Maori to become endangered.
In response to language revitalisation efforts, the (re) vernacularisation of te reo Māori over the past 30 years has exhibited a complex combination of both bottom-up and top-down LPP. Within this, early pāngarau lexical developments were largely driven by local schools and their communities, which sometimes centred on the maintenance of their tribal dialects, often in conflict with later LPP agency language goals. 
Subsequently, lexication for pāngarau was influenced by macro-level sociolinguistic beliefs such as linguistic purism, which in turn have influenced the technical approach to creating terms and may have created particular pedagogical issues, such as a lack of intertranslatability between te reo Māori and English at the higher levels of mathematics study. 
While Māori-medium schooling has contributed significantly to language revitalisation in the past 30 years, its development has been very ad hoc. In the absence of a “formal” language plan for Māori-medium education, policy has been significantly driven by national education (English-medium) imperatives since the late 1970s to the present day. On the other hand, these policies have favoured mathematics education and directly supported the development of the Māori-medium specialised lexicon and register.

text: Te Reo Tātai: The Development of a Mathematics Register for Māori-Medium Schooling This thesis investigates the development of a lexicon and register to facilitate the teaching of mathematics in the medium of te reo Māori. This sociolinguistic development is situated within the wider Māori language revitalisation movement in Aotearoa/New Zealand, of which Māori-medium education is a central component. 
Lexication of a language is a subdomain of corpus planning. Corpus, status and language-in-education planning are considered the three major interconnected domains of language planning and policy (LPP). For decades, the primary focus of LPP research has been on the activities of states and their agencies at the macro (national) level. The significance of this study is that it addresses this gap in the research, by investigating the development of LPP at the meso/micro-level—in this case, with respect to the development of a mathematics register for an endangered indigenous language, te reo Māori.
The thesis draws on two major participant data sources. The first is the narratives of key individuals at the forefront of lexical development for Māori-medium mathematics who recounted their experiences. The second is interviews with principals and teachers from two Māori-medium case study schools to examine their own learning and usage of the standardised pāngarau lexicon.
Two complementary theoretical frameworks were used to investigate the topic. First, an LPP theoretical framework was applied to investigate the complex relationships between the various levels of LPP that have impacted on the evolution of te reo Māori and Māori-medium schooling. Second, a linguistic framework, systemic functional linguistics (SFL), was used to investigate the linguistic and pedagogical issues.
Thesis findings show that the status of te reo Māori was variously affected by linguistic ideologies such as assimilation, which in turn led to such policies as English only in schooling. As a consequence, at the micro-level of LPP, Māori-medium mathematics development went into a hiatus for over 100 years, and at the macro-level, considerable language shift occurred to English, causing te reo Maori to become endangered.
In response to language revitalisation efforts, the (re) vernacularisation of te reo Māori over the past 30 years has exhibited a complex combination of both bottom-up and top-down LPP. Within this, early pāngarau lexical developments were largely driven by local schools and their communities, which sometimes centred on the maintenance of their tribal dialects, often in conflict with later LPP agency language goals. 
Subsequently, lexication for pāngarau was influenced by macro-level sociolinguistic beliefs such as linguistic purism, which in turn have influenced the technical approach to creating terms and may have created particular pedagogical issues, such as a lack of intertranslatability between te reo Māori and English at the higher levels of mathematics study. 
While Māori-medium schooling has contributed significantly to language revitalisation in the past 30 years, its development has been very ad hoc. In the absence of a “formal” language plan for Māori-medium education, policy has been significantly driven by national education (English-medium) imperatives since the late 1970s to the present day. On the other hand, these policies have favoured mathematics education and directly supported the development of the Māori-medium specialised lexicon and register.

year: 2015