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Localization of IRP-1 mRNA and an Analysis of Hydrogen Peroxide in Gravistimulated Maize Pulvini

Permanent Link: http://ncf.sobek.ufl.edu/NCFE003581/00001

Material Information

Title: Localization of IRP-1 mRNA and an Analysis of Hydrogen Peroxide in Gravistimulated Maize Pulvini
Physical Description: Book
Language: English
Creator: Tinnirello, Stella M. N.
Publisher: New College of Florida
Place of Publication: Sarasota, Fla.
Creation Date: 2005
Publication Date: 2005

Subjects

Subjects / Keywords: Iron Regulatory Protein-1
Hydrogen Peroxide
Maize
Gravistimulation
Genre: bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Plants integrate many stimuli in order to respond to their environment. In the case of a tipped (gravistimulated) maize (Zea mays L.) stem, the pulvinus is the tissue responsible for the reorientation of the plant in the gravitropic response via increased elongation of the cells on its lower side. The maize pulvinus is a useful model system in gravitropic studies, because it is a discrete region of tissue responsible for both the detection of gravity and the growth response. Previously, an iron regulatory protein-1 (IRP-1) homologue was found to be upregulated in gravistimulated maize pulvini. In the present study, localization of the IRP-1 mRNA was visualized using in situ hybridization in pulvini of plants that had been reoriented for various intervals of time. We noted an increased presence of the IRP-1 mRNA in the lower half of the pulvinus after 30 min of gravistimulation, which is 3-4 hr before the growth response becomes visible. The IRP-1 mRNA was prominently localized in the bundle sheath cells, which are the amyloplast containing cells thought to play a role in the initial detection of gravity. By 48 h, the asymmetry switched such that the bundle sheath cells of the upper half were distinctly labeled. The timing and location of IRP-1 mRNA expression all suggest that IRP-1 may play a role in the signaling and/or early response pathways following gravistimulation. Because IRP-1 can also function as a cytoplasmic aconitase and hydrogen peroxide regulates its interconversion, in mammalian systems, we also investigated the presence of hydrogen peroxide in gravistimulated pulvini. Using the peroxide stain 3,3'- diaminobenzidine (DAB), we found that pulvini tipped for 1 min showed positive staining for peroxide in association with the xylem walls and with what appeared to be the amyloplasts of the bundle sheath cells surrounding the peripheral vascular bundles. At 30 min of gravistimulation, the DAB stain was more diffuse, for it was seen throughout the cytoplasm of the bundle sheath cells. In contrast, the peroxide was located in numerous cell types in vertical control pulvini presumably due to wounding during harvesting, but not specifically in association with amyloplasts. These findings suggests that hydrogen peroxide could play a role in the gravity response and that its distribution may be regulated in this process, since both the gravistimulated and vertical pulvini were harvested in the same manner.
Statement of Responsibility: by Stella M. N. Tinnirello
Thesis: Thesis (B.A.) -- New College of Florida, 2005
Electronic Access: RESTRICTED TO NCF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE
Bibliography: Includes bibliographical references.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Local: Faculty Sponsor: Clore, Amy

Record Information

Source Institution: New College of Florida
Holding Location: New College of Florida
Rights Management: Applicable rights reserved.
Classification: local - S.T. 2005 T5
System ID: NCFE003581:00001

Permanent Link: http://ncf.sobek.ufl.edu/NCFE003581/00001

Material Information

Title: Localization of IRP-1 mRNA and an Analysis of Hydrogen Peroxide in Gravistimulated Maize Pulvini
Physical Description: Book
Language: English
Creator: Tinnirello, Stella M. N.
Publisher: New College of Florida
Place of Publication: Sarasota, Fla.
Creation Date: 2005
Publication Date: 2005

Subjects

Subjects / Keywords: Iron Regulatory Protein-1
Hydrogen Peroxide
Maize
Gravistimulation
Genre: bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Plants integrate many stimuli in order to respond to their environment. In the case of a tipped (gravistimulated) maize (Zea mays L.) stem, the pulvinus is the tissue responsible for the reorientation of the plant in the gravitropic response via increased elongation of the cells on its lower side. The maize pulvinus is a useful model system in gravitropic studies, because it is a discrete region of tissue responsible for both the detection of gravity and the growth response. Previously, an iron regulatory protein-1 (IRP-1) homologue was found to be upregulated in gravistimulated maize pulvini. In the present study, localization of the IRP-1 mRNA was visualized using in situ hybridization in pulvini of plants that had been reoriented for various intervals of time. We noted an increased presence of the IRP-1 mRNA in the lower half of the pulvinus after 30 min of gravistimulation, which is 3-4 hr before the growth response becomes visible. The IRP-1 mRNA was prominently localized in the bundle sheath cells, which are the amyloplast containing cells thought to play a role in the initial detection of gravity. By 48 h, the asymmetry switched such that the bundle sheath cells of the upper half were distinctly labeled. The timing and location of IRP-1 mRNA expression all suggest that IRP-1 may play a role in the signaling and/or early response pathways following gravistimulation. Because IRP-1 can also function as a cytoplasmic aconitase and hydrogen peroxide regulates its interconversion, in mammalian systems, we also investigated the presence of hydrogen peroxide in gravistimulated pulvini. Using the peroxide stain 3,3'- diaminobenzidine (DAB), we found that pulvini tipped for 1 min showed positive staining for peroxide in association with the xylem walls and with what appeared to be the amyloplasts of the bundle sheath cells surrounding the peripheral vascular bundles. At 30 min of gravistimulation, the DAB stain was more diffuse, for it was seen throughout the cytoplasm of the bundle sheath cells. In contrast, the peroxide was located in numerous cell types in vertical control pulvini presumably due to wounding during harvesting, but not specifically in association with amyloplasts. These findings suggests that hydrogen peroxide could play a role in the gravity response and that its distribution may be regulated in this process, since both the gravistimulated and vertical pulvini were harvested in the same manner.
Statement of Responsibility: by Stella M. N. Tinnirello
Thesis: Thesis (B.A.) -- New College of Florida, 2005
Electronic Access: RESTRICTED TO NCF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE
Bibliography: Includes bibliographical references.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Local: Faculty Sponsor: Clore, Amy

Record Information

Source Institution: New College of Florida
Holding Location: New College of Florida
Rights Management: Applicable rights reserved.
Classification: local - S.T. 2005 T5
System ID: NCFE003581:00001

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