- Assistant Professor
- Bolin Hall
- Bolin 218 D
Assistant Professor in the Department of Biology. Specializes in botany, confocal light microscopy, electron microscopy, sample preparation, and plant morphology.
Past and present work involves studying chemical and structural alterations to plant root cell wall ultra-structure in response to flooding stress. Focus area in cell wall pectin and hemicellulose biochemistry as revealed with through ultrastructural changes and fluorescence immunolabeling pattern variation.
Current class instruction includes:
BIOL 1114, General Life I
BIOL 3213, Botany: Plant Life
|Miami University (Oxford, Ohio)||Doctor of Philosophy - Botany||2021|
|University of Oklahoma||Master of Science - Botany||2016|
|Frostburg State University||Bachelor of Science - Biology (1st degree), Chemistry (2nd degree)||2009|
|Employer||Position||Start Date||End Date|
|Midwestern State University||Assistant Professor||06/01/2022|
|Marietta College||Visiting Assistant Professor||08/23/2021||05/31/2022|
|Miami University||Graduate Teaching Assistant, Ph.D. Candidate||08/16/2016||08/20/2021|
|University of Oklahoma||Graduate Teaching Assistant, M.S.||07/22/2013||07/29/2016|
|Allegany College of Maryland||Adjunct Professor (Biology)||01/23/2012||07/26/2013|
Immunoprofiling of Cell Wall Carbohydrate Modifications during Flooding-Induced Aerenchyma Formation in Fabaceae Roots
Pegg, T. J., Edelmann, R. R., Gladish, D. K. 2020. âImmunoprofiling of Cell Wall Carbohydrate Modifications during Flooding-Induced Aerenchyma Formation in Fabaceae Rootsâ Frontiers in Plant Science DOI: https://doi.org/10.3389/fpls.2019.01805
ï»¿Understanding plant adaptation mechanisms to prolonged water immersion provides options for genetic modification of existing crops to create cultivars more tolerant of periodic flooding. An important advancement in understanding flooding adaptation would be to elucidate mechanisms, such as aerenchyma air-space formation induced by hypoxic conditions, consistent with prolonged immersion. Lysigenous aerenchyma formation occurs through programmed cell death (PCD), which may entail the chemical modification of polysaccharides in root tissue cell walls. We investigated if a relationship exists between modification of pectic polysaccharides through de-methyl esterification (DME) and the formation of root aerenchyma in select Fabaceae species. To test this hypothesis, we first characterized the progression of aerenchyma formation within the vascular stele of three different legumesâPisum sativum, Cicer arietinum, and Phaseolus coccineusâthrough traditional light microscopy histological staining and scanning electron microscopy. We assessed alterations in stele morphology, cavity dimensions, and cell wall chemistry. Then we conducted an immunolabeling protocol to detect specific degrees of DME among species during a 48-hour flooding time series. Additionally, we performed an enzymatic pretreatment to remove select cell wall polymers prior to immunolabeling for DME pectins. We were able to determine that all species possessed similar aerenchyma formation mechanisms that begin with degradation of root vascular stele metaxylem cells. Immunolabeling results demonstrated DME occurs prior to aerenchyma formation and prepares vascular tissues for the beginning of cavity formation in flooded roots. Furthermore, enzymatic pretreatment demonstrated that removal of cellulose and select hemicellulosic carbohydrates unmasks additional antigen binding sites for DME pectin antibodies. These results suggest that additional carbohydrate modification may be required to permit DME and subsequent enzyme activity to form aerenchyma. By providing a greater understanding of cell wall pectin remodeling among legume species, we encourage further investigation into the mechanism of carbohydrate modifications during aerenchyma formation and possible avenues for flood-tolerance improvement of legume crops.
Progression of Cell Wall Matrix Alterations during Aerenchyma Formation in Pisum sativum Root Cortical Cells
Pegg, T. J., Edelmann, R. R., Gladish, D. K. 2018. âProgression of Cell Wall Matrix Alterations during Aerenchyma Formation in Pisum sativum Root Cortical Cellsâ Proceedings of Microscopy & Microanalysis DOI: https://doi.org/10.1017/S1431927618007377
Algae to angiosperms: Autoﬂuorescence for rapid visualization of plant anatomy among diverse taxa
Pegg TJ, Gladish DK, Baker RL. Algae to angiosperms: Autofluorescence for rapid visualization of plant anatomy among diverse taxa. Appl Plant Sci. 2021 Jul 2;9(6):e11437. doi: 10.1002/aps3.11437.
Premise: Fluorescence microscopy is an effective tool for viewing plant internal anatomy. However, using fluorescent antibodies or labels hinders throughput. We present a minimal protocol that takes advantage of inherent autofluorescence and aldehyde-induced fluorescence in plant cellular and subcellular structures to markedly increase throughput in cellular and ultrastructural visualization.
Methods and Results: Twelve species distributed across the plant phylogeny were each subjected to five fixative treatments: 1% paraformaldehyde and 2% glutaraldehyde, 2% paraformaldehyde, 2% glutaraldehyde, formalin-acid-alcohol (FAA), and 70% ethanol. Samples were prepared by embedding and mechanically sectioning or via whole mount. A confocal laser scanning system was used to collect micrographs. We evaluated and compared fixative influence on sample structural preservation and tissue autofluorescence.
Conclusions: Formaldehyde fixation of Viridiplantae taxa samples generates useful structural data while requiring no additional histological staining or clearing. In addition, a fluorescence-capable microscope is the only specialized equipment required for image acquisition. The minimal protocol developed in this experiment enables high-throughput sample processing by eliminating the need for multi-day preparations.
Keywords: Viridiplantae; aldehyde; anatomy; autofluorescence; cellular; fixation; methods; microscopy; subcellular; throughput.