Heather Wood | Trent University (original) (raw)

Papers by Heather Wood

Research paper thumbnail of Demographic and socio-economic characteristics of men choosing vasectomy

Journal of Biosocial Science, 1978

Page 1. /. biosoc. Sci. (1978) 10,133-139 DEMOGRAPHIC AND SOCIO-ECONOMIC CHARACTERISTICS OF MEN C... more Page 1. /. biosoc. Sci. (1978) 10,133-139 DEMOGRAPHIC AND SOCIO-ECONOMIC CHARACTERISTICS OF MEN CHOOSING VASECTOMY MARY A. PARSONS AND HEATHER A. WOOD Department of Human Biology and Health, University of Surrey, Guildford ...

Research paper thumbnail of Colonization of the Cecal Mucosa by Helicobacter hepaticus Impacts the Diversity of the Indigenous Microbiota

Infection and Immunity, 2005

Establishment of mucosal and/or luminal colonization is the first step in the pathogenesis of man... more Establishment of mucosal and/or luminal colonization is the first step in the pathogenesis of many gastrointestinal bacterial pathogens. The pathogen must be able to establish itself in the face of competition from the complex microbial community that is already in place. We used culture-independent methods to monitor the colonization of the cecal mucosa of Helicobacter-free mice following experimental infection with the pathogen Helicobacter hepaticus. Two days after infection, H. hepaticus comprised a minor component of the mucosaassociated microbiota, but within 14 days, it became the dominant member of the community. Colonization of the mucosa by H. hepaticus was associated with a decrease in the overall diversity of the microbial community, in large part due to changes in evenness resulting from the relative dominance of H. hepaticus as a member of the community. Our results demonstrate that invasion of the complex gastrointestinal microbial community by a pathogenic microorganism causes reproducible and significant disturbances in the community structure. The use of non-culture-based methods to monitor these changes should lead to a greater understanding of the ecological principles that govern pathogen invasion and may lead to novel methods for the prevention and control of gastrointestinal pathogens.

Research paper thumbnail of Modulation of Host Immune Responses by the Cytolethal Distending Toxin of Helicobacter hepaticus

Infection and Immunity, 2006

Helicobacter hepaticus leads to chronic gastrointestinal inflammation and neoplasia in susceptibl... more Helicobacter hepaticus leads to chronic gastrointestinal inflammation and neoplasia in susceptible strains. To determine the role of the virulence factor cytolethal distending toxin (CDT) in the pathogenesis of this organism, interleukin-10-deficient (IL-10 ؊/؊ ) mice were experimentally infected with wild-type H. hepaticus and a CDT-deficient isogenic mutant. Both wild-type H. hepaticus and the CDTdeficient mutant successfully colonized IL-10 ؊/؊ mice, and they reached similar tissue levels by 6 weeks after infection. Only animals infected with wild-type type H. hepaticus developed significant typhlocolitis. However, by 4 months after infection, the CDT-deficient mutant was no longer detectable in IL-10 ؊/؊ mice, whereas wild-type H. hepaticus persisted for the 8-month duration of the experiment.

Research paper thumbnail of Signal-sequence recognition by an Escherichia coli ribonucleoprotein complex

Research paper thumbnail of Evolutionary conserved nucleotides within the E.coli 4.5S RNA are required for association with P48 in vitro and for optimal function in vivo

Nucleic Acids Research, 1992

E.coli 4.5S RNA is homologous to domain IV of eukaryotic SRP7S RNA, the RNA component of the sign... more E.coli 4.5S RNA is homologous to domain IV of eukaryotic SRP7S RNA, the RNA component of the signal recognition particle. The 4.5S RNA is associated in vivo with a 48kD protein (P48), which is homologous to a protein component of the signal recognition particle, SRP54. In addition to secondary structural features, a number of nucleotides are conserved between the 4.5S RNA and domain IV of all other characterised SRP-like RNAs from eubacteria, archaebacteria and eukaryotes. This domain consists of an extended stem-loop structure; conserved nucleotides lie within the terminal loop and within single-stranded regions bulged from the stem immediately preceding the loop. This conserved region is a candidate for the SRP54/P48 binding site. To determine the functional importance of this region within the 4.5S RNA, mutations were introduced into the 4.5S RNA coding sequence. Mutated alleles were tested for their function in vivo and for the ability of the corresponding RNAs to bind P48 in vitro. Single point mutations in conserved nucleotides within the terminal tetranucleotide loop do not affect P48 binding in vitro and produce only slight growth defects. This suggests that the sequence of the loop may be important for the structure of the molecule rather than for specific interactions with P48. On the other hand, nucleotides within the single-stranded regions bulged from the stem were found to be important both for the binding of P48 to the RNA and for optimal function of the RNA in vivo.

Research paper thumbnail of Signed English in the classroom, II. Structural and pragmatic aspects of teachers' speech and sign

First Language, 1991

ABSTRACT In the first paper in this series (SEC I) we investigated the effects of teaching style ... more ABSTRACT In the first paper in this series (SEC I) we investigated the effects of teaching style on pupil participation in discourse in classrooms where Signed English (SE) was employed for communication. In the present paper, we analyse the same classroom conversations from ...

Research paper thumbnail of Signed English in the classroom, I. Teaching style and child participation

First Language, 1991

ABSTRACT Signed English is a system of communication involving the simul-taneous use of spoken an... more ABSTRACT Signed English is a system of communication involving the simul-taneous use of spoken and signed morphemes expressed in English grammar. It has been invented for use with pre-lingually deaf children, the aspiration behind its creation being both to facilitate ...

Research paper thumbnail of An Experimental Evaluation of Four Face-to-Face Teaching Strategies

International Journal of Behavioral Development, 1978

This study tests a number of predictions about the effectiveness of four different strategies for... more This study tests a number of predictions about the effectiveness of four different strategies for teaching three to four year old children how to master a difficult construction task. These strategies were derived from previous studies of mother-child and experimenter-child interactions in ...

Research paper thumbnail of Vygotsky, Tutoring and Learning

Oxford Review of Education, 1996

ABSTRACT This paper starts with a selectiveexamination of research into individualised tutoring. ... more ABSTRACT This paper starts with a selectiveexamination of research into individualised tutoring. We articulate theoreticaland empirical evidence to support the conclusion that a set of common principlesgoverns such tutoring. Theseprinciples apply to the provision of ...

Research paper thumbnail of On Becoming a Tutor: Toward an Ontogenetic Model

Cognition and Instruction, 1995

Research paper thumbnail of Questioning the Pre‐School Child

Educational Review, 1983

EJ280501 - Questioning the Pre-School Child.

Research paper thumbnail of Contingency in tutoring and learning

Learning and Instruction, 1996

Research paper thumbnail of Demographic and socio-economic characteristics of men choosing vasectomy

Journal of Biosocial Science, 1978

Page 1. /. biosoc. Sci. (1978) 10,133-139 DEMOGRAPHIC AND SOCIO-ECONOMIC CHARACTERISTICS OF MEN C... more Page 1. /. biosoc. Sci. (1978) 10,133-139 DEMOGRAPHIC AND SOCIO-ECONOMIC CHARACTERISTICS OF MEN CHOOSING VASECTOMY MARY A. PARSONS AND HEATHER A. WOOD Department of Human Biology and Health, University of Surrey, Guildford ...

Research paper thumbnail of Colonization of the Cecal Mucosa by Helicobacter hepaticus Impacts the Diversity of the Indigenous Microbiota

Infection and Immunity, 2005

Establishment of mucosal and/or luminal colonization is the first step in the pathogenesis of man... more Establishment of mucosal and/or luminal colonization is the first step in the pathogenesis of many gastrointestinal bacterial pathogens. The pathogen must be able to establish itself in the face of competition from the complex microbial community that is already in place. We used culture-independent methods to monitor the colonization of the cecal mucosa of Helicobacter-free mice following experimental infection with the pathogen Helicobacter hepaticus. Two days after infection, H. hepaticus comprised a minor component of the mucosaassociated microbiota, but within 14 days, it became the dominant member of the community. Colonization of the mucosa by H. hepaticus was associated with a decrease in the overall diversity of the microbial community, in large part due to changes in evenness resulting from the relative dominance of H. hepaticus as a member of the community. Our results demonstrate that invasion of the complex gastrointestinal microbial community by a pathogenic microorganism causes reproducible and significant disturbances in the community structure. The use of non-culture-based methods to monitor these changes should lead to a greater understanding of the ecological principles that govern pathogen invasion and may lead to novel methods for the prevention and control of gastrointestinal pathogens.

Research paper thumbnail of Modulation of Host Immune Responses by the Cytolethal Distending Toxin of Helicobacter hepaticus

Infection and Immunity, 2006

Helicobacter hepaticus leads to chronic gastrointestinal inflammation and neoplasia in susceptibl... more Helicobacter hepaticus leads to chronic gastrointestinal inflammation and neoplasia in susceptible strains. To determine the role of the virulence factor cytolethal distending toxin (CDT) in the pathogenesis of this organism, interleukin-10-deficient (IL-10 ؊/؊ ) mice were experimentally infected with wild-type H. hepaticus and a CDT-deficient isogenic mutant. Both wild-type H. hepaticus and the CDTdeficient mutant successfully colonized IL-10 ؊/؊ mice, and they reached similar tissue levels by 6 weeks after infection. Only animals infected with wild-type type H. hepaticus developed significant typhlocolitis. However, by 4 months after infection, the CDT-deficient mutant was no longer detectable in IL-10 ؊/؊ mice, whereas wild-type H. hepaticus persisted for the 8-month duration of the experiment.

Research paper thumbnail of Signal-sequence recognition by an Escherichia coli ribonucleoprotein complex

Research paper thumbnail of Evolutionary conserved nucleotides within the E.coli 4.5S RNA are required for association with P48 in vitro and for optimal function in vivo

Nucleic Acids Research, 1992

E.coli 4.5S RNA is homologous to domain IV of eukaryotic SRP7S RNA, the RNA component of the sign... more E.coli 4.5S RNA is homologous to domain IV of eukaryotic SRP7S RNA, the RNA component of the signal recognition particle. The 4.5S RNA is associated in vivo with a 48kD protein (P48), which is homologous to a protein component of the signal recognition particle, SRP54. In addition to secondary structural features, a number of nucleotides are conserved between the 4.5S RNA and domain IV of all other characterised SRP-like RNAs from eubacteria, archaebacteria and eukaryotes. This domain consists of an extended stem-loop structure; conserved nucleotides lie within the terminal loop and within single-stranded regions bulged from the stem immediately preceding the loop. This conserved region is a candidate for the SRP54/P48 binding site. To determine the functional importance of this region within the 4.5S RNA, mutations were introduced into the 4.5S RNA coding sequence. Mutated alleles were tested for their function in vivo and for the ability of the corresponding RNAs to bind P48 in vitro. Single point mutations in conserved nucleotides within the terminal tetranucleotide loop do not affect P48 binding in vitro and produce only slight growth defects. This suggests that the sequence of the loop may be important for the structure of the molecule rather than for specific interactions with P48. On the other hand, nucleotides within the single-stranded regions bulged from the stem were found to be important both for the binding of P48 to the RNA and for optimal function of the RNA in vivo.

Research paper thumbnail of Signed English in the classroom, II. Structural and pragmatic aspects of teachers' speech and sign

First Language, 1991

ABSTRACT In the first paper in this series (SEC I) we investigated the effects of teaching style ... more ABSTRACT In the first paper in this series (SEC I) we investigated the effects of teaching style on pupil participation in discourse in classrooms where Signed English (SE) was employed for communication. In the present paper, we analyse the same classroom conversations from ...

Research paper thumbnail of Signed English in the classroom, I. Teaching style and child participation

First Language, 1991

ABSTRACT Signed English is a system of communication involving the simul-taneous use of spoken an... more ABSTRACT Signed English is a system of communication involving the simul-taneous use of spoken and signed morphemes expressed in English grammar. It has been invented for use with pre-lingually deaf children, the aspiration behind its creation being both to facilitate ...

Research paper thumbnail of An Experimental Evaluation of Four Face-to-Face Teaching Strategies

International Journal of Behavioral Development, 1978

This study tests a number of predictions about the effectiveness of four different strategies for... more This study tests a number of predictions about the effectiveness of four different strategies for teaching three to four year old children how to master a difficult construction task. These strategies were derived from previous studies of mother-child and experimenter-child interactions in ...

Research paper thumbnail of Vygotsky, Tutoring and Learning

Oxford Review of Education, 1996

ABSTRACT This paper starts with a selectiveexamination of research into individualised tutoring. ... more ABSTRACT This paper starts with a selectiveexamination of research into individualised tutoring. We articulate theoreticaland empirical evidence to support the conclusion that a set of common principlesgoverns such tutoring. Theseprinciples apply to the provision of ...

Research paper thumbnail of On Becoming a Tutor: Toward an Ontogenetic Model

Cognition and Instruction, 1995

Research paper thumbnail of Questioning the Pre‐School Child

Educational Review, 1983

EJ280501 - Questioning the Pre-School Child.

Research paper thumbnail of Contingency in tutoring and learning

Learning and Instruction, 1996