title: Evolution of Bacillus subtilis: A Novel Phenotype and its Challenges

authors: Murray, Mitchell John

subjects: Evolution

abstract: The enzyme LeuB from the last common ancestor of the firmicutes has been statistically recreated using several different methods. This project deals with two versions, Rec/LG and Rec/EX. To better understand these resurrected enzymes, the proteins were crystallised. Despite extensive efforts to produce crystals of diffraction quality, none of the crystals developed during this project were large enough to be of any use in X-Ray crystallography. Strains of Bacillus subtilis were genetically modified to each have one of either Rec/LG or Rec/Rec/EX in place of the native leuB gene, and then were allowed to evolve alongside an unmodified strain for 500 generations. Attempts were made to extract DNA from the evolved strains at different points throughout the evolution experiment for whole genome sequencing, and to amplify the leuB gene via PCR for direct comparisons of changes that may have occurred to the leuB gene over the course of the evolution experiment. These attempts were ultimately unsuccessful. In lieu of this genetic data, phenotypic changes to the evolved strains were characterised. A new phenotype appeared extremely early on in the experiment (by generation 54), and in less than 300 generations had swept to fixation in 9 independent strains. In all cases, this phenotype included poor growth on LB agar plates, small colonies, and small cells. Similar changes have been observed before in laboratory experiments of B. subtilis, but none occurred so quickly or so uniformly across independent samples.

text: Evolution of Bacillus subtilis: A Novel Phenotype and its Challenges The enzyme LeuB from the last common ancestor of the firmicutes has been statistically recreated using several different methods. This project deals with two versions, Rec/LG and Rec/EX. To better understand these resurrected enzymes, the proteins were crystallised. Despite extensive efforts to produce crystals of diffraction quality, none of the crystals developed during this project were large enough to be of any use in X-Ray crystallography. Strains of Bacillus subtilis were genetically modified to each have one of either Rec/LG or Rec/Rec/EX in place of the native leuB gene, and then were allowed to evolve alongside an unmodified strain for 500 generations. Attempts were made to extract DNA from the evolved strains at different points throughout the evolution experiment for whole genome sequencing, and to amplify the leuB gene via PCR for direct comparisons of changes that may have occurred to the leuB gene over the course of the evolution experiment. These attempts were ultimately unsuccessful. In lieu of this genetic data, phenotypic changes to the evolved strains were characterised. A new phenotype appeared extremely early on in the experiment (by generation 54), and in less than 300 generations had swept to fixation in 9 independent strains. In all cases, this phenotype included poor growth on LB agar plates, small colonies, and small cells. Similar changes have been observed before in laboratory experiments of B. subtilis, but none occurred so quickly or so uniformly across independent samples.

year: 2018

title: Review of W.V.O. Quine, “From Stimulus to Science”

authors: Legg, Catherine

abstract: This article reviews the book “From Stimulus to Science” by W.V.O. Quine.

text: Review of W.V.O. Quine, “From Stimulus to Science” This article reviews the book “From Stimulus to Science” by W.V.O. Quine.

year: 1996

title: Exploring the nature of intimate relationships: A Māori perspective

authors: King, Pita

subjects: Maori

abstract: The 2002 World Report on Violence states that violence occurs in about 70 percent of intimate relationships (Krug, Dahlberg, Mercy, Zwi, & Lozano, 2002). New Zealand research indicates that more than a quarter of relationships have experienced intimate partner violence (IPV), with Māori (Indigenous people of New Zealand) women three times more likely to experience IPV in their lifetime. Utilising Kaupapa Māori (Māori-centred approach) and narrative methodologies, this paper explores the nature of intimate relationships from a Māori perspective, investigating how Māori initiate intimate relationships, attempt to maintain positive intimate relationships and when applicable, exit intimate relationships. The findings from two case studies reveal that intimate relationships involve identity negotiation and an incorporation of cultural values. Communication processes are highlighted as a facilitating factor of intimate relationships.

text: Exploring the nature of intimate relationships: A Māori perspective The 2002 World Report on Violence states that violence occurs in about 70 percent of intimate relationships (Krug, Dahlberg, Mercy, Zwi, & Lozano, 2002). New Zealand research indicates that more than a quarter of relationships have experienced intimate partner violence (IPV), with Māori (Indigenous people of New Zealand) women three times more likely to experience IPV in their lifetime. Utilising Kaupapa Māori (Māori-centred approach) and narrative methodologies, this paper explores the nature of intimate relationships from a Māori perspective, investigating how Māori initiate intimate relationships, attempt to maintain positive intimate relationships and when applicable, exit intimate relationships. The findings from two case studies reveal that intimate relationships involve identity negotiation and an incorporation of cultural values. Communication processes are highlighted as a facilitating factor of intimate relationships.

year: 2012