title: Isolation and Characterisation of Bacterial Metabolites as Potential Wood Preservatives

authors: O'Callahan, Diahanna Rachelle

subjects: lactic acid bacteria

abstract: The durability of wood has traditionally relied on the use of heavy metals and toxic compounds to deter wood degrading fungi. Conventional wood preservatives such as Chromated Copper Arsenate (CCA) have been widely used to control wood degrade for many decades, however public pressure over perceived environmental and health risks have led to recent restrictions for use in some countries. This issue has focused the need for research towards environmentally friendly (benign) wood preservatives including compounds such as plant extractives and microbial metabolites.

Previously chilli waste has been shown to have moderate antifungal activity against common wood sapstain fungi. Furthermore, Lactobacillus sp. isolated from chilli showed synergistic activity with chilli against these fungi. The intention of this study was to further develop this work, by isolating and identifying the range of bacteria from chilli waste, screening for antifungal activity against wood decay fungi then investigating any possible synergy between the isolates and chilli waste. 

Initially a quick screening 96-well optical density assay was optimised which allowed the screening of lactic acid bacterial metabolites against wood decay fungi. This technique proved to be comparable to a commonly used growth rate method and has potential as a standard initial screening method in the laboratory. 

Seven isolates from chilli juice had an antifungal effect on the wood decay fungus Oligoporus placenta and were identified using 16S rRNA phylogenetic techniques as Lactobacillus brevis, Leuconostoc mesenteroides subsp. mesenteroides (three isolates), L. mesenteroides subsp. cremoris, L. pseudomesenteroides and Gluconobacter oxydans. Cell-free supernatants of these isolates were used to treat wood blocks which were then exposed to wood decay fungi. L. brevis metabolites showed the greatest inhibition of wood decay and were identified as lactic and acetic acids by high performance liquid chromatography (HPLC) amongst other techniques. The media in which the bacteria were grown also had an antifungal effect on wood decay fungi most likely due to its hygroscopicity increasing wood moisture content to a point inhibitory to decay fungi.

Synergy between the bacterial metabolites and chilli juice was examined using the optical density assay and it was discovered that two bacteria showed complete inhibition of decay fungi when grown in chilli juice. However, when subjected to a wood assay, both L. brevis and L. mesenteroides subsp. cremoris did not give satisfactory control of decay fungi suggesting the main mechanism of fungal inhibition was due to increased moisture content of wood induced by the specific media initially used in this study. 

Further research should determine whether the isolated bacteria can be induced to increase metabolite production and if this would improve antifungal activity. Ultimately these bacterial metabolites and chilli combined or alone, may not be suitable for long term protection against wood decay, but may provide a solution to other fungal degradation issues.

text: Isolation and Characterisation of Bacterial Metabolites as Potential Wood Preservatives The durability of wood has traditionally relied on the use of heavy metals and toxic compounds to deter wood degrading fungi. Conventional wood preservatives such as Chromated Copper Arsenate (CCA) have been widely used to control wood degrade for many decades, however public pressure over perceived environmental and health risks have led to recent restrictions for use in some countries. This issue has focused the need for research towards environmentally friendly (benign) wood preservatives including compounds such as plant extractives and microbial metabolites.

Previously chilli waste has been shown to have moderate antifungal activity against common wood sapstain fungi. Furthermore, Lactobacillus sp. isolated from chilli showed synergistic activity with chilli against these fungi. The intention of this study was to further develop this work, by isolating and identifying the range of bacteria from chilli waste, screening for antifungal activity against wood decay fungi then investigating any possible synergy between the isolates and chilli waste. 

Initially a quick screening 96-well optical density assay was optimised which allowed the screening of lactic acid bacterial metabolites against wood decay fungi. This technique proved to be comparable to a commonly used growth rate method and has potential as a standard initial screening method in the laboratory. 

Seven isolates from chilli juice had an antifungal effect on the wood decay fungus Oligoporus placenta and were identified using 16S rRNA phylogenetic techniques as Lactobacillus brevis, Leuconostoc mesenteroides subsp. mesenteroides (three isolates), L. mesenteroides subsp. cremoris, L. pseudomesenteroides and Gluconobacter oxydans. Cell-free supernatants of these isolates were used to treat wood blocks which were then exposed to wood decay fungi. L. brevis metabolites showed the greatest inhibition of wood decay and were identified as lactic and acetic acids by high performance liquid chromatography (HPLC) amongst other techniques. The media in which the bacteria were grown also had an antifungal effect on wood decay fungi most likely due to its hygroscopicity increasing wood moisture content to a point inhibitory to decay fungi.

Synergy between the bacterial metabolites and chilli juice was examined using the optical density assay and it was discovered that two bacteria showed complete inhibition of decay fungi when grown in chilli juice. However, when subjected to a wood assay, both L. brevis and L. mesenteroides subsp. cremoris did not give satisfactory control of decay fungi suggesting the main mechanism of fungal inhibition was due to increased moisture content of wood induced by the specific media initially used in this study. 

Further research should determine whether the isolated bacteria can be induced to increase metabolite production and if this would improve antifungal activity. Ultimately these bacterial metabolites and chilli combined or alone, may not be suitable for long term protection against wood decay, but may provide a solution to other fungal degradation issues.

year: 2012

title: Analysing pedagogical change: Physics teachers' responses to a new curriculum.

authors: Fernandez, Teresa Sushama

subjects: teaching

abstract: This paper describes teachers' attempts to implement the 1994 New Zealand physics curriculum in the first year of its introduction to secondary schools in 1998. Analysis of interviews with 10 physics teachers and the three curriculum writers led to the identification of a number of barriers to changes in pedagogical practices. The barriers identified aligned with factors that had been identified by other researchers as important influences on teachers undergoing change. It is argued that a sociocultural perspective suggests that there were three main reasons why significant pedagogical change was not occasioned by the curriculum document. Firstly, there was very limited knowledge about why changes were being implemented. Secondly, there was little social and system support for the curriculum change. Finally, teachers had no time to focus on and reflect on the change.

text: Analysing pedagogical change: Physics teachers' responses to a new curriculum. This paper describes teachers' attempts to implement the 1994 New Zealand physics curriculum in the first year of its introduction to secondary schools in 1998. Analysis of interviews with 10 physics teachers and the three curriculum writers led to the identification of a number of barriers to changes in pedagogical practices. The barriers identified aligned with factors that had been identified by other researchers as important influences on teachers undergoing change. It is argued that a sociocultural perspective suggests that there were three main reasons why significant pedagogical change was not occasioned by the curriculum document. Firstly, there was very limited knowledge about why changes were being implemented. Secondly, there was little social and system support for the curriculum change. Finally, teachers had no time to focus on and reflect on the change.

year: 2003

title: Homai raa. Kia purutia, kia hereherea, taawhiwhi taamau. Ka pai. Taawhiwhi  taumau, he tauira waiora a Waikato : The creation of a Waikato-specific Maaori health model

authors: Haggie, Marrin Brian Pikitawhaki

subjects: Taawhiwhi Taamau

abstract: This Doctoral rangahau (research) sought to create a Maaori (Indigenous people of New Zealand) health model specific to the health needs and desires of the people of Waikato (The collective name of the tribes of the Waikato basin). Globally, minority populations (including Maaori) are consistently and disproportionately over represented in many health, education and incarceration statistics. Colonisation, oppression and racial prejudices have been identified as the root causes for the statistical imbalances prevalent in society. Indigenous populations have endured suffering caused by disconnection from heritage, traditional practices, ancestral beliefs and the natural environment. All are consequences of legislative enforcement and an oppressive, colonialist attitude that patronises indigenous populations (i.e., that assumes the coloniser knows what is best for the colonised). 

For the majority of colonisation, the health models and frameworks intended to benefit indigenous peoples, yet designed and implemented by colonial based, oppressive governments and by institutions rooted in colonialist ideals, have consistently failed to provide and deliver health and wellness for indigenous peoples. The fact that indigenous peoples’ health continues to be poorer than their non-indigenous counterparts, in the majority of health measures, suggests models and frameworks designed by non-indigenous people do not work for indigenous populations. This has led to an emergence of indigenous and minority populations’ movements seeking to emancipate themselves from the shackles of colonial oppression. 

Pioneering health models and frameworks designed to counter the failures of those designed by the oppressor have provided salvation for indigenous peoples and have allowed the voices of minority populations to be heard in the health and wellbeing context; however the majority of these models have been overly generic. Yet, they have provided foundations that now must be built upon to enable a focus on what specific populations require to ensure their health and lifestyle ideals are supported and strengthened.

As whaanau (family), marae (place of gathering and belonging for interrelated families), hapuu (subtribe), and as an iwi (tribe), Waikato have a responsibility to our taiao (natural environment), ourselves and to future generations to ensure the health of Waikato and that Waikatotanga (Waikato culture and practice) continues to grow, prosper, and flourish. Therefore, as a polity we must assert the control and direction of our iwi by determining and creating our own models and frameworks to ensure the survival, the growth, and the success of our people.

This Rangahau Kaupapa Waikato (Waikato focused research) is centered on the question ‘What elements must be considered in the creation and the application of a Waikato-specific, Maaori health model?’ Contemporary literature and research regarding health and the impacts on Indigenous and Maaori health specifically, was used to review the successes and failures of contemporary health models. 

Supported and framed by a Rangahau Kaupapa Maaori (Maaori focused research) approach, this Rangahau Kaupapa Waikato utilised Waikato koorero (stories), beliefs, practices and methodologies, interspersed with Qualitative Methodology and Thematic Analysis. Fourteen semi-structured interviews with tribal leaders and holders of tribal knowledge, referred to as taniwha, were conducted. Each taniwha shared their knowledge, understandings, and experiences to inform and contribute to the creation of a holistic health model specific to the iwi of Waikato.

The findings illustrate continued connection to the Waikato awa (river), the taiao (natural environment), wairuatanga (spirituality), ancestral knowledge and practices, the Kiingitanga (Maaori King Movement) and to the iwi itself are critical to the perpetuation of the waiora (health) of the Waikato iwi and of Waikatotanga in its multiple forms.

The model created as the primary outcome of this research, The Taawhiwhi Taamau Model of Waiora (Taawhiwhi Taamau), was designed to act as a vehicle which seeks to enable individual iwi members, and the polities that they belong, to achieve Mana-motuhake (autonomy) and self-determination of their own health. Taawhiwhi Taamau seeks to inform its adopters that Mana-motuhake can be achieved without having to compromise any of the tikanga (protocol) and kawa (custom) of our iwi and of our ancestors in favour of colonial government introduced, western ideals. Thereby removing the oppressor from the implementation and application of health. 

Taawhiwhi Taamau is a health model entrenched in Waikatotanga that utilises the beliefs and practices of our ancestors, and subsequently, our iwi to facilitate Tupuna (ancestor) Guided Living. The model encourages the individual iwi member to build solid foundations of waiora, seek knowledge and understanding of our tupuna, and use the experiences in life to act as taniwha for others seeking guidance, knowledge, connection, understanding and waiora. 

The adoption and practice of Taawhiwhi Taamau suggests individuals will find a new, refreshed connection to tupuna, maatauranga (wisdom, knowledge), wairuatanga and Waikatotanga, therefore, increasing waiora. Increased waiora of the individual increases the waiora and the capacity of one’s whaanau, marae and hapuu thereby increasing the waiora and the capacity of the iwi. Increased waiora and capacity of the iwi increases the likelihood of Waikatotanga, maatauranga, wairuatanga and, thus, the perpetuation of Tupuna Guided Living. Consequently, encapsulating the essence of Taawhiwhi Taamau as a model and as the lesson learned in the Pai Maarire Te Kura o te Ahiahi, ‘Homai ra, kia purutia, kia hereherea, taawhiwhi taamau. Ka Pai’.

text: Homai raa. Kia purutia, kia hereherea, taawhiwhi taamau. Ka pai. Taawhiwhi  taumau, he tauira waiora a Waikato : The creation of a Waikato-specific Maaori health model This Doctoral rangahau (research) sought to create a Maaori (Indigenous people of New Zealand) health model specific to the health needs and desires of the people of Waikato (The collective name of the tribes of the Waikato basin). Globally, minority populations (including Maaori) are consistently and disproportionately over represented in many health, education and incarceration statistics. Colonisation, oppression and racial prejudices have been identified as the root causes for the statistical imbalances prevalent in society. Indigenous populations have endured suffering caused by disconnection from heritage, traditional practices, ancestral beliefs and the natural environment. All are consequences of legislative enforcement and an oppressive, colonialist attitude that patronises indigenous populations (i.e., that assumes the coloniser knows what is best for the colonised). 

For the majority of colonisation, the health models and frameworks intended to benefit indigenous peoples, yet designed and implemented by colonial based, oppressive governments and by institutions rooted in colonialist ideals, have consistently failed to provide and deliver health and wellness for indigenous peoples. The fact that indigenous peoples’ health continues to be poorer than their non-indigenous counterparts, in the majority of health measures, suggests models and frameworks designed by non-indigenous people do not work for indigenous populations. This has led to an emergence of indigenous and minority populations’ movements seeking to emancipate themselves from the shackles of colonial oppression. 

Pioneering health models and frameworks designed to counter the failures of those designed by the oppressor have provided salvation for indigenous peoples and have allowed the voices of minority populations to be heard in the health and wellbeing context; however the majority of these models have been overly generic. Yet, they have provided foundations that now must be built upon to enable a focus on what specific populations require to ensure their health and lifestyle ideals are supported and strengthened.

As whaanau (family), marae (place of gathering and belonging for interrelated families), hapuu (subtribe), and as an iwi (tribe), Waikato have a responsibility to our taiao (natural environment), ourselves and to future generations to ensure the health of Waikato and that Waikatotanga (Waikato culture and practice) continues to grow, prosper, and flourish. Therefore, as a polity we must assert the control and direction of our iwi by determining and creating our own models and frameworks to ensure the survival, the growth, and the success of our people.

This Rangahau Kaupapa Waikato (Waikato focused research) is centered on the question ‘What elements must be considered in the creation and the application of a Waikato-specific, Maaori health model?’ Contemporary literature and research regarding health and the impacts on Indigenous and Maaori health specifically, was used to review the successes and failures of contemporary health models. 

Supported and framed by a Rangahau Kaupapa Maaori (Maaori focused research) approach, this Rangahau Kaupapa Waikato utilised Waikato koorero (stories), beliefs, practices and methodologies, interspersed with Qualitative Methodology and Thematic Analysis. Fourteen semi-structured interviews with tribal leaders and holders of tribal knowledge, referred to as taniwha, were conducted. Each taniwha shared their knowledge, understandings, and experiences to inform and contribute to the creation of a holistic health model specific to the iwi of Waikato.

The findings illustrate continued connection to the Waikato awa (river), the taiao (natural environment), wairuatanga (spirituality), ancestral knowledge and practices, the Kiingitanga (Maaori King Movement) and to the iwi itself are critical to the perpetuation of the waiora (health) of the Waikato iwi and of Waikatotanga in its multiple forms.

The model created as the primary outcome of this research, The Taawhiwhi Taamau Model of Waiora (Taawhiwhi Taamau), was designed to act as a vehicle which seeks to enable individual iwi members, and the polities that they belong, to achieve Mana-motuhake (autonomy) and self-determination of their own health. Taawhiwhi Taamau seeks to inform its adopters that Mana-motuhake can be achieved without having to compromise any of the tikanga (protocol) and kawa (custom) of our iwi and of our ancestors in favour of colonial government introduced, western ideals. Thereby removing the oppressor from the implementation and application of health. 

Taawhiwhi Taamau is a health model entrenched in Waikatotanga that utilises the beliefs and practices of our ancestors, and subsequently, our iwi to facilitate Tupuna (ancestor) Guided Living. The model encourages the individual iwi member to build solid foundations of waiora, seek knowledge and understanding of our tupuna, and use the experiences in life to act as taniwha for others seeking guidance, knowledge, connection, understanding and waiora. 

The adoption and practice of Taawhiwhi Taamau suggests individuals will find a new, refreshed connection to tupuna, maatauranga (wisdom, knowledge), wairuatanga and Waikatotanga, therefore, increasing waiora. Increased waiora of the individual increases the waiora and the capacity of one’s whaanau, marae and hapuu thereby increasing the waiora and the capacity of the iwi. Increased waiora and capacity of the iwi increases the likelihood of Waikatotanga, maatauranga, wairuatanga and, thus, the perpetuation of Tupuna Guided Living. Consequently, encapsulating the essence of Taawhiwhi Taamau as a model and as the lesson learned in the Pai Maarire Te Kura o te Ahiahi, ‘Homai ra, kia purutia, kia hereherea, taawhiwhi taamau. Ka Pai’.

year: 2021