title: Quantification of Nitro-toxins in Karaka (Corynocarpus laevigatus) Drupes

authors: MacAskill, Jessica Jane

abstract: The karaka (Corynocarpus laevigatus) is a tree native to New Zealand (NZ), found throughout the North and South Islands. Traditionally, many parts of the karaka were used by Māori, however the parts of the karaka of most interest are the berry and nut as they were valuable food sources, in particular the nut. Karaka was known to be a toxin-bearing food, however implementation of a traditional baking and soaking process meant that the nuts were left in states fit for consumption, more often than not. The nuts also had the benefit of being able to be stored for future use when other food sources were short in supply. Karaka was readily consumed up until the 1950s, after this consumption rates decreased rapidly, after the toxic effects were associated with the incorrect preparation of the nuts.

Studies on karaka have revealed that the toxicity of the nuts primarily arises from various nitropropanoyl glucopyranoses (NPGs), twelve of which have been detected in karaka. The quantity of these NPGs has been infrequently studied and it is often only one of the NPGs-karakin which is quantified, although it is believed the toxicity in nuts arises collectively from all of the NPGs. As a result, there is the need to be able to quantify the NPGs in karaka and look at potential toxin removal techniques. If toxin removal can be accomplished, there is the potential for karaka to be a marketable ‘traditional’ or ‘Kiwi’ food item. Additionally, the toxins removed as a by-product may prove to have their own potential commercial applications, for example as insecticides or repellents. 

Since all the NPGs are assumed to be toxic, a method was developed to quantify the total toxicity in the nuts. The method involves the release of NPA via acid hydrolysis of the nitropropanoyl ester groups of the NPGs. The NPA is then able to be measured and subsequently quantified using HPLC. The method incorporates a correction factor (CF) that was determined to give the original NPA content at a time of zero (NPA0), accounting for the unavoidable loss of NPA that arises from the hydrolysis method.

The average quantity of NPA in karaka nuts was found to range from 50.25 to 138.62 g kg-1 (dry weight) which is equivalent to 5.0 to 13.9%. These are much higher percentages than any previously reported because the method used in this study measured total NPA. Earlier methods measured a limited range of NPGs (often a single NPG) unhydrolysed and could have missed NPA arising from other compounds that contribute to total toxicity. Additionally, the concentrations of NPA in karaka nuts were influenced by a number of factors including intra and inter tree variation, storage conditions and ripeness. Although quantification was focused on determining NPA content in nuts, a test conducted also showed NPA to be present in increasingly lower levels in the berry flesh, shell and pellicle respectively. 

Nuts were subjected to various potential industrial processing techniques, treatment times and conditions, in order to determine their efficacy for toxin removal. Treatments included boiling, microwave cooking, soxhlet extraction, oven roasting, autoclaving and cold-water treatments. The efficiency of each treatment varied considerably, with both heat and water proving to be beneficial in toxin removal. However, treatments involving water were found to be more effective than heat treatments alone. Out of all treatment types, times and conditions tested, none were found to leave nuts with a NPA concentration lower than the estimated safe level of daily consumption for a 70 kg adult (< 1.75 mg). Additionally, only some of the treatments resulted in nuts being left in visually appealing states. At present, toxin removal by a single process in order to render karaka nuts safe to consume appears to be an impractical activity. However, if treatment protocols were combined and modified, there is the potential for the development of an effective detoxification process. Furthermore, tests on the treatment solutions revealed that NPA can be obtained in solution as a by-product of nut treatment; with cold-water proving to be more effective than treatments that also used heat. Obtaining NPA as a by-product of toxin removal in nuts appears to be a feasible option for a natural source of NPA.

text: Quantification of Nitro-toxins in Karaka (Corynocarpus laevigatus) Drupes The karaka (Corynocarpus laevigatus) is a tree native to New Zealand (NZ), found throughout the North and South Islands. Traditionally, many parts of the karaka were used by Māori, however the parts of the karaka of most interest are the berry and nut as they were valuable food sources, in particular the nut. Karaka was known to be a toxin-bearing food, however implementation of a traditional baking and soaking process meant that the nuts were left in states fit for consumption, more often than not. The nuts also had the benefit of being able to be stored for future use when other food sources were short in supply. Karaka was readily consumed up until the 1950s, after this consumption rates decreased rapidly, after the toxic effects were associated with the incorrect preparation of the nuts.

Studies on karaka have revealed that the toxicity of the nuts primarily arises from various nitropropanoyl glucopyranoses (NPGs), twelve of which have been detected in karaka. The quantity of these NPGs has been infrequently studied and it is often only one of the NPGs-karakin which is quantified, although it is believed the toxicity in nuts arises collectively from all of the NPGs. As a result, there is the need to be able to quantify the NPGs in karaka and look at potential toxin removal techniques. If toxin removal can be accomplished, there is the potential for karaka to be a marketable ‘traditional’ or ‘Kiwi’ food item. Additionally, the toxins removed as a by-product may prove to have their own potential commercial applications, for example as insecticides or repellents. 

Since all the NPGs are assumed to be toxic, a method was developed to quantify the total toxicity in the nuts. The method involves the release of NPA via acid hydrolysis of the nitropropanoyl ester groups of the NPGs. The NPA is then able to be measured and subsequently quantified using HPLC. The method incorporates a correction factor (CF) that was determined to give the original NPA content at a time of zero (NPA0), accounting for the unavoidable loss of NPA that arises from the hydrolysis method.

The average quantity of NPA in karaka nuts was found to range from 50.25 to 138.62 g kg-1 (dry weight) which is equivalent to 5.0 to 13.9%. These are much higher percentages than any previously reported because the method used in this study measured total NPA. Earlier methods measured a limited range of NPGs (often a single NPG) unhydrolysed and could have missed NPA arising from other compounds that contribute to total toxicity. Additionally, the concentrations of NPA in karaka nuts were influenced by a number of factors including intra and inter tree variation, storage conditions and ripeness. Although quantification was focused on determining NPA content in nuts, a test conducted also showed NPA to be present in increasingly lower levels in the berry flesh, shell and pellicle respectively. 

Nuts were subjected to various potential industrial processing techniques, treatment times and conditions, in order to determine their efficacy for toxin removal. Treatments included boiling, microwave cooking, soxhlet extraction, oven roasting, autoclaving and cold-water treatments. The efficiency of each treatment varied considerably, with both heat and water proving to be beneficial in toxin removal. However, treatments involving water were found to be more effective than heat treatments alone. Out of all treatment types, times and conditions tested, none were found to leave nuts with a NPA concentration lower than the estimated safe level of daily consumption for a 70 kg adult (< 1.75 mg). Additionally, only some of the treatments resulted in nuts being left in visually appealing states. At present, toxin removal by a single process in order to render karaka nuts safe to consume appears to be an impractical activity. However, if treatment protocols were combined and modified, there is the potential for the development of an effective detoxification process. Furthermore, tests on the treatment solutions revealed that NPA can be obtained in solution as a by-product of nut treatment; with cold-water proving to be more effective than treatments that also used heat. Obtaining NPA as a by-product of toxin removal in nuts appears to be a feasible option for a natural source of NPA.

year: 2013

title: Ecological, genetic and cultural status of Solanum aviculare, poroporo (Solanaceae)

authors: Weavers, Graeme Morris

subjects: Solanum aviculare

abstract: Solanum aviculare, endemic to Australasia, is an opportunist pioneer secondary successional plant occupying disturbed and open lowland habitats, and was an important medicinal and cultural species to Māori known as poroporo. It is currently in 'decline', the ecological decline appearing to correspond to a decline in knowledge and cultural use of the species. To gain understanding of the reasons for the decline, enhance ecological knowledge, assist conservation and cultural restoration of Solanum aviculare this research documented the successional role and cycle of regeneration dynamics and tactics, established morphological characteristics, investigated the genetic diversity and recorded cultural and conservation information.
The successional status and role was identified. Growth data identified cohort development and inter-site differences, metadata found height and crown spread growth to be significantly correlated and likely part of an early reproduction and dispersal strategy. Germination of soil cores from differing depths confirmed a viable seed bank exists sufficient for species maintenance. Viable seed spread via animal gut passage was determined by germination and chemical tests, results showed rats passed higher rates of viable seed than birds. Seed germination trials with stratified and fresh seed confirmed temporal and depth behaviour, flowering observation documented temporal differences with the closely allied species Solanum laciniatum, indicating a relationship to stasis induction. Leaf morphology studies documented differences between the two allied species and proposed further nomenclature.
Genetic diversity was investigated through the use of PCR/ISSR techniques. Chloroplast DNA was extracted by CTAB and DNA kit protocols. CTAB extraction was unable to effectively remove RNA, although use of DNA samples with high quantities of RNA confirmed that RNA was not an inhibiting factor in PCR production. The production of consistent reliable ISSR bands proved difficult, with no technical explanation found. ISSR findings indicate that Solanum aviculare is highly monomorphic, consisting of predominant invariant monomorphic loci. Twenty primers were tested with no polymorphic loci
identified and no intra species variation documented. Indications were also that Solanum aviculare and Solanum laciniatum are inter species invariant on monomorphic loci. Monomorphic loci may possibly be the evolutionary markers of generic differentiation within Solanum.
Surveys identified Solanum aviculare as uncommon and rare, existing mainly as single plants or small groups in the majority of areas surveyed. The Threatened and Uncommon Plant listing of Solanum aviculare as an 'at risk declining' species is confirmed and a further Recommendation category proposed. Ecological decline and corresponding decline in cultural use and knowledge of Solanum aviculare was identified through specialist interviews; appearing to be related to removal from Māori of control over their land. The name poroporo being now associated mainly with non indigenous Solanum species. Māori cultural concepts in practice were highlighted as fundamentally important to reversing the decline, with an example of a successful traditional practice based (tikanga) integrative collaborative restoration program being documented.
This research forwards that optimal collaborative solutions, programs integrating scientific and tikanga knowledge and practices, provide the best opportunity of reversing the declining trend and for increasing and maintaining knowledge associated with the traditional role of poroporo.

text: Ecological, genetic and cultural status of Solanum aviculare, poroporo (Solanaceae) Solanum aviculare, endemic to Australasia, is an opportunist pioneer secondary successional plant occupying disturbed and open lowland habitats, and was an important medicinal and cultural species to Māori known as poroporo. It is currently in 'decline', the ecological decline appearing to correspond to a decline in knowledge and cultural use of the species. To gain understanding of the reasons for the decline, enhance ecological knowledge, assist conservation and cultural restoration of Solanum aviculare this research documented the successional role and cycle of regeneration dynamics and tactics, established morphological characteristics, investigated the genetic diversity and recorded cultural and conservation information.
The successional status and role was identified. Growth data identified cohort development and inter-site differences, metadata found height and crown spread growth to be significantly correlated and likely part of an early reproduction and dispersal strategy. Germination of soil cores from differing depths confirmed a viable seed bank exists sufficient for species maintenance. Viable seed spread via animal gut passage was determined by germination and chemical tests, results showed rats passed higher rates of viable seed than birds. Seed germination trials with stratified and fresh seed confirmed temporal and depth behaviour, flowering observation documented temporal differences with the closely allied species Solanum laciniatum, indicating a relationship to stasis induction. Leaf morphology studies documented differences between the two allied species and proposed further nomenclature.
Genetic diversity was investigated through the use of PCR/ISSR techniques. Chloroplast DNA was extracted by CTAB and DNA kit protocols. CTAB extraction was unable to effectively remove RNA, although use of DNA samples with high quantities of RNA confirmed that RNA was not an inhibiting factor in PCR production. The production of consistent reliable ISSR bands proved difficult, with no technical explanation found. ISSR findings indicate that Solanum aviculare is highly monomorphic, consisting of predominant invariant monomorphic loci. Twenty primers were tested with no polymorphic loci
identified and no intra species variation documented. Indications were also that Solanum aviculare and Solanum laciniatum are inter species invariant on monomorphic loci. Monomorphic loci may possibly be the evolutionary markers of generic differentiation within Solanum.
Surveys identified Solanum aviculare as uncommon and rare, existing mainly as single plants or small groups in the majority of areas surveyed. The Threatened and Uncommon Plant listing of Solanum aviculare as an 'at risk declining' species is confirmed and a further Recommendation category proposed. Ecological decline and corresponding decline in cultural use and knowledge of Solanum aviculare was identified through specialist interviews; appearing to be related to removal from Māori of control over their land. The name poroporo being now associated mainly with non indigenous Solanum species. Māori cultural concepts in practice were highlighted as fundamentally important to reversing the decline, with an example of a successful traditional practice based (tikanga) integrative collaborative restoration program being documented.
This research forwards that optimal collaborative solutions, programs integrating scientific and tikanga knowledge and practices, provide the best opportunity of reversing the declining trend and for increasing and maintaining knowledge associated with the traditional role of poroporo.

year: 2010

title: Investigating the use of coreboards by children with developmental disabilities and teachers in a school environment.

authors: Oldfield, Ainsley

subjects: Autism

abstract: Coreboards have become popular as an aid for individuals with disorders, such as Autism Spectrum Disorder (ASD), who may have issues with speech-language production, but who also often lack more fundamental functional communication skills. The aims of this study were to explore the extent coreboards as an Augmentative and Alternative Communication (AAC) were a useful tool for children with developmental disabilities and their teachers to communicate independently and functionally, if they were used effectively in the school environment, if they were used for their intended purpose, and if they were used to facilitate functional communication skills for children with developmental disabilities. The research in this project involved data collection on student and teacher communicative behaviour. The participants in this study were three children aged 9 to 10 with developmental disabilities and their teacher and learning support assistants. The study is a mixed-methods descriptive design and data was collected by direct observations being recorded on a data sheet. The main findings are the student participants did use the coreboard for independent communication as they each individually initiated with the coreboard less than 3% of the time and two of the student participants purpose of initiating use of the coreboard was unknown over half the time. Furthermore, if the adult participants are unable to determine what the purpose of the coreboard use is from the student participants, then the communication act will not be successful as the adult participant will not be able to respond appropriately to the student participant and the lack of success will discourage the student participants from initiating in the future.

text: Investigating the use of coreboards by children with developmental disabilities and teachers in a school environment. Coreboards have become popular as an aid for individuals with disorders, such as Autism Spectrum Disorder (ASD), who may have issues with speech-language production, but who also often lack more fundamental functional communication skills. The aims of this study were to explore the extent coreboards as an Augmentative and Alternative Communication (AAC) were a useful tool for children with developmental disabilities and their teachers to communicate independently and functionally, if they were used effectively in the school environment, if they were used for their intended purpose, and if they were used to facilitate functional communication skills for children with developmental disabilities. The research in this project involved data collection on student and teacher communicative behaviour. The participants in this study were three children aged 9 to 10 with developmental disabilities and their teacher and learning support assistants. The study is a mixed-methods descriptive design and data was collected by direct observations being recorded on a data sheet. The main findings are the student participants did use the coreboard for independent communication as they each individually initiated with the coreboard less than 3% of the time and two of the student participants purpose of initiating use of the coreboard was unknown over half the time. Furthermore, if the adult participants are unable to determine what the purpose of the coreboard use is from the student participants, then the communication act will not be successful as the adult participant will not be able to respond appropriately to the student participant and the lack of success will discourage the student participants from initiating in the future.

year: 2021