Superoxide Dismutase in Arabidopsis: An Eclectic Enzyme Family with Disparate Regulation and Protein Localization1

A number of environmental stresses can lead to enhanced production of superoxide within plant tissues, and plants are believed to rely on the enzyme superoxide dismutase (SOD) to detoxify this reactive oxygen species. We have identified seven cDNAs and genes for SOD in Arabidopsis. These consist of three CuZnSODs (CSD1, CSD2, and CSD3), three FeSODs (FSD1, FSD2, and FSD3), and one MnSOD (MSD1). The chromosomal location of these seven SOD genes has been established. To study this enzyme family, antibodies were generated against five proteins: CSD1, CSD2, CSD3, FSD1, and MSD1. Using these antisera and nondenaturing-polyacrylamide gel electrophoresis enzyme assays, we identified protein and activity for two CuZnSODs and for FeSOD and MnSOD in Arabidopsis rosette tissue. Additionally, subcellular fractionation studies revealed the presence of CSD2 and FeSOD protein within Arabidopsis chloroplasts. The seven SOD mRNAs and the four proteins identified were differentially regulated in response to various light regimes, ozone fumigation, and ultraviolet-B irradiation. To our knowledge, this is the first report of a large-scale analysis of the regulation of multiple SOD proteins in a plant species.

Diary, 1747

The 1747 diary contains brief records (usually one or two a month) written in a small booklet of blank pages. The scattered entries focus on community news including local deaths and murder. The March 23 entry reads, "Will a Mulatto of Benj & Jno Walkers shot a negro of Jno Denny [Jun] he died on the spot." Entries in November recount the Boston Knowles Riot.

Letter from Stephen Longfellow to Daniel Appleton White, 1799 May 29

Stephen Longfellow wrote this letter in Portland, Maine on May 29, 1799; it was sent to his friend, Daniel Appleton White, in Medford, Massachusetts. In the letter, Longfellow describes the Election Day festivities among the "plebeans" in Portland, which he apparently found both amusing and upsetting. He compares the horses pulling their sleds to Don Quixote's horse, Rocinante. He also writes about mutual friends, including John Henry Tudor and Jabez Kimball, and bemoans the behavior of the current members of Phi Beta Kappa among the Harvard College undergraduates, whom he insists have sunk the society below its former "exalted station."

Letter from Daniel Upton to James Savage, 1799 September 29

Daniel Upton wrote this letter from Machias, Maine on September 29, 1799; it is addressed to James Savage, who was then a freshman at Harvard College. In the letter, Upton advises Savage to study ardently, avoiding the temptation to procrastinate. He thanks Savage for having sent him a copy of "Mr. Lowell's oration" and sends greetings to a Mr. Holbrook and Mr. Jones. He also passes along the fond wishes of those in Machias who know Savage, including John Cooper and his wife, Phineas Bruce and his wife, and Hannah Bruce (Upton's future wife). Upton explains that he is writing the letter in a hurry because he is sending it on board with Captain Merryman, who is about to set sail, presumably for Boston.