title: Structure and function of an acetyl xylan esterase (est2a) from the rumen bacterium Butyrivibrio proteoclasticus

authors: Till, Marisa

abstract: Butyrivibrio proteoclasticus is a significant component of the microbial population of the rumen of dairy cattle. It is a xylan-degrading organism whose genome encodes a large number of open reading frames annotated as fibre-degrading enzymes. We have determined the three-dimensional structure of Est2A, an acetyl xylan esterase from B. proteoclasticus, at 2.1 Å resolution, along with the structure of an inactive mutant (H351A) at 2.0 Å resolution. The structure reveals two domains - a C-terminal SGNH domain and an N-terminal jelly-roll domain typical of CE2 family structures. The structures are accompanied by experimentally determined enzymatic parameters against two model substrates, para-nitrophenyl acetate and para-nitrophenyl butyrate. The suite of fibre-degrading enzymes produced by B. proteoclasticus provides a rich source of new enzymes of potential use in industrial settings.

text: Structure and function of an acetyl xylan esterase (est2a) from the rumen bacterium Butyrivibrio proteoclasticus Butyrivibrio proteoclasticus is a significant component of the microbial population of the rumen of dairy cattle. It is a xylan-degrading organism whose genome encodes a large number of open reading frames annotated as fibre-degrading enzymes. We have determined the three-dimensional structure of Est2A, an acetyl xylan esterase from B. proteoclasticus, at 2.1 Å resolution, along with the structure of an inactive mutant (H351A) at 2.0 Å resolution. The structure reveals two domains - a C-terminal SGNH domain and an N-terminal jelly-roll domain typical of CE2 family structures. The structures are accompanied by experimentally determined enzymatic parameters against two model substrates, para-nitrophenyl acetate and para-nitrophenyl butyrate. The suite of fibre-degrading enzymes produced by B. proteoclasticus provides a rich source of new enzymes of potential use in industrial settings.

year: 2013

title: Ultraconserved words point to deep language ancestry across Eurasia

authors: Pagel, Mark

subjects: cultural evolution

abstract: The search for ever deeper relationships among the World’s languages is bedeviled by the fact that most words evolve too rapidly to preserve evidence of their ancestry beyond 5,000 to 9,000 y. On the other hand, quantitative modeling indicates that some “ultraconserved” words exist that might be used to find evidence for deep linguistic relationships beyond that time barrier. Here we use a statistical model, which takes into account the frequency with which words are used in common everyday speech, to predict the existence of a set of such highly conserved words among seven language families of Eurasia postulated to form a linguistic superfamily that evolved from a common ancestor around 15,000 y ago. We derive a dated phylogenetic tree of this proposed superfamily with a time-depth of ∼14,450 y, implying that some frequently used words have been retained in related forms since the end of the last ice age. Words used more than once per 1,000 in everyday speech were 7- to 10-times more likely to show deep ancestry on this tree. Our results suggest a remarkable fidelity in the transmission of some words and give theoretical justification to the search for features of language that might be preserved across wide spans of time and geography.

text: Ultraconserved words point to deep language ancestry across Eurasia The search for ever deeper relationships among the World’s languages is bedeviled by the fact that most words evolve too rapidly to preserve evidence of their ancestry beyond 5,000 to 9,000 y. On the other hand, quantitative modeling indicates that some “ultraconserved” words exist that might be used to find evidence for deep linguistic relationships beyond that time barrier. Here we use a statistical model, which takes into account the frequency with which words are used in common everyday speech, to predict the existence of a set of such highly conserved words among seven language families of Eurasia postulated to form a linguistic superfamily that evolved from a common ancestor around 15,000 y ago. We derive a dated phylogenetic tree of this proposed superfamily with a time-depth of ∼14,450 y, implying that some frequently used words have been retained in related forms since the end of the last ice age. Words used more than once per 1,000 in everyday speech were 7- to 10-times more likely to show deep ancestry on this tree. Our results suggest a remarkable fidelity in the transmission of some words and give theoretical justification to the search for features of language that might be preserved across wide spans of time and geography.

year: 2013

title: Different Coloured Tears: Bicultural Bereavement Perspectives

authors: Edge, Kiri

subjects: Maori

abstract: The research explored the pathways that Māori and Pākehā  bicultural whānau follow in  mourning, grieving and moving on through life, in response to the death of a signficant loved one. Of specific interest were sites of conflict, processes of negotiation and pathways to resolution occuring across cultural worlds whilst deciding on, organising and enacting tangi/funeral rituals for the deceased. These explorations were founded on the Pou Toko Manawa of the framework offered by Te Tiriti o Waitangi/The Treaty of Waitangi and related principles. The research was conducted across two distinct yet inter-related studies. The first study explored the bereavement experiences of individuals belonging to Māori and Pākehā bicultural families, offering insights related to the emergence of conflict, negotiation and pathways to resolution. The insights gathered gave rise to further explorations concerned with the perspectives of experts who facilitate, mediate and enact bereavement processes. As the second study, the expert perspectives revealed supports, constraints and legalitites that emerge in bicultural bereavement processes. The culmination of the two studies engender a multi-faceted understanding of key concepts, issues and processes in bicultural bereavement, and the cultural and socio-political landscapes within which these events are located. In considering the research findings within the theorectical framework of Te Tiriti o Waitangi/The Treaty of Waitangi, the research offers a unique bicultural and New Zealand specific understanding of conflict and resolution.

text: Different Coloured Tears: Bicultural Bereavement Perspectives The research explored the pathways that Māori and Pākehā  bicultural whānau follow in  mourning, grieving and moving on through life, in response to the death of a signficant loved one. Of specific interest were sites of conflict, processes of negotiation and pathways to resolution occuring across cultural worlds whilst deciding on, organising and enacting tangi/funeral rituals for the deceased. These explorations were founded on the Pou Toko Manawa of the framework offered by Te Tiriti o Waitangi/The Treaty of Waitangi and related principles. The research was conducted across two distinct yet inter-related studies. The first study explored the bereavement experiences of individuals belonging to Māori and Pākehā bicultural families, offering insights related to the emergence of conflict, negotiation and pathways to resolution. The insights gathered gave rise to further explorations concerned with the perspectives of experts who facilitate, mediate and enact bereavement processes. As the second study, the expert perspectives revealed supports, constraints and legalitites that emerge in bicultural bereavement processes. The culmination of the two studies engender a multi-faceted understanding of key concepts, issues and processes in bicultural bereavement, and the cultural and socio-political landscapes within which these events are located. In considering the research findings within the theorectical framework of Te Tiriti o Waitangi/The Treaty of Waitangi, the research offers a unique bicultural and New Zealand specific understanding of conflict and resolution.

year: 2017