Publications by authors named "Morgan R Smith"

3 Publications

  • Page 1 of 1

Polyphosphate is an extracellular signal that can facilitate bacterial survival in eukaryotic cells.

Proc Natl Acad Sci U S A 2020 12 2;117(50):31923-31934. Epub 2020 Dec 2.

Department of Biology, Texas A&M University, College Station, TX 77843-3474

Polyphosphate is a linear chain of phosphate residues and is present in organisms ranging from bacteria to humans. Pathogens such as accumulate polyphosphate, and reduced expression of the polyphosphate kinase that synthesizes polyphosphate decreases their survival. How polyphosphate potentiates pathogenicity is poorly understood. K-12 do not accumulate detectable levels of extracellular polyphosphate and have poor survival after phagocytosis by or human macrophages. In contrast, and accumulate detectable levels of extracellular polyphosphate, and have relatively better survival after phagocytosis by or macrophages. Adding extracellular polyphosphate increased survival after phagocytosis by and macrophages. Reducing expression of polyphosphate kinase 1 in reduced extracellular polyphosphate and reduced survival in and macrophages, and this was reversed by the addition of extracellular polyphosphate. Conversely, treatment of and macrophages with recombinant yeast exopolyphosphatase reduced the survival of phagocytosed or cells lacking the putative polyphosphate receptor GrlD had reduced sensitivity to polyphosphate and, compared to wild-type cells, showed increased killing of phagocytosed and Polyphosphate inhibited phagosome acidification and lysosome activity in and macrophages and reduced early endosomal markers in macrophages. Together, these results suggest that bacterial polyphosphate potentiates pathogenicity by acting as an extracellular signal that inhibits phagosome maturation.
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December 2020

Extracellular signaling in Dictyostelium.

Int J Dev Biol 2019 ;63(8-9-10):395-405

Department of Biology, Texas A∧M University, College Station, Texas, USA.

In the last few decades, we have learned a considerable amount about how eukaryotic cells communicate with each other, and what it is the cells are telling each other. The simplicity of Dictyostelium discoideum, and the wide variety of available tools to study this organism, makes it the equivalent of a hydrogen atom for cell and developmental biology. Studies using Dictyostelium have pioneered a good deal of our understanding of eukaryotic cell communication. In this review, we will present a brief overview of how Dictyostelium cells use extracellular signals to attract each other, repel each other, sense their local cell density, sense whether the nearby cells are starving or stressed, count themselves to organize the formation of structures containing a regulated number of cells, sense the volume they are in, and organize their multicellular development. Although we are probably just beginning to learn what the cells are telling each other, the elucidation of Dictyostelium extracellular signals has already led to the development of possible therapeutics for human diseases.
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July 2020

Shaping a valued learning journey: Student satisfaction with learning in undergraduate nursing programs, a grounded theory study.

Nurse Educ Today 2018 May 22;64:175-179. Epub 2018 Feb 22.

The Hopkins Centre Research for Rehabilitation and Resilience, Women's Wellness Research Group, Menzies Health Institute Queensland, School of Nursing and Midwifery, Griffith University, Gold Coast campus, Quensland 4222, Australia. Electronic address:

Background: Student satisfaction is a quality measure of increasing importance in undergraduate programs, including nursing programs. To date theories of student satisfaction have focused primarily on students' perceptions of the educational environment rather than their perceptions of learning. Understanding how students determine satisfaction with learning is necessary to facilitate student learning across a range of educational contexts and meet the expectations of diverse stakeholders.

Objectives: To understand undergraduate nursing students' satisfaction with learning.

Design: Constructivist grounded theory methodology was used to identify how nursing students determined satisfaction with learning.

Settings: Two large, multi-campus, nursing schools in Australia.

Participants: Seventeen demographically diverse undergraduate nursing students studying different stages of a three year program participated in the study.

Methods: Twenty nine semi-structured interviews were conducted. Students were invited to describe situations where they had been satisfied or dissatisfied with their learning. A constructivist grounded theory approach was used to analyse the data.

Results: Students are satisfied with learning when they shape a valued learning journey that accommodates social contexts of self, university and nursing workplace. The theory has three phases. Phase 1 - orienting self to valued learning in the pedagogical landscape; phase 2 - engaging with valued learning experiences across diverse pedagogical terrain; and phase 3 - recognising valued achievement along the way.

Conclusion: When students experience a valued learning journey they are satisfied with their learning. Student satisfaction with learning is unique to the individual, changes over time and maybe transient or sustained, mild or intense. Finding from the research indicate areas where nurse academics may facilitate satisfaction with learning in undergraduate nursing programs while mindful of the expectations of other stakeholders such as the university, nurse registering authorities, employers and the receivers of nursing care.
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May 2018