Terpenoid-based defenses in conifers: cDNA cloning, characterization, and functional expression of wound-inducible (E)-α-bisabolene synthase from grand fir (Abies grandis)

(E)-α-Bisabolene synthase is one of two wound-inducible sesquiterpene synthases of grand fir (Abies grandis), and the olefin product of this cyclization reaction is considered to be the precursor in Abies species of todomatuic acid, juvabione, and related insect juvenile hormone mimics. A cDNA encoding (E)-α-bisabolene synthase was isolated from a wound-induced grand fir stem library by a PCR-based strategy and was functionally expressed in Escherichia coli and shown to produce (E)-α-bisabolene as the sole product from farnesyl diphosphate. The expressed synthase has a deduced size of 93.8 kDa and a pI of 5.03, exhibits other properties typical of sesquiterpene synthases, and resembles in sequence other terpenoid synthases with the exception of a large amino-terminal insertion corresponding to Pro81–Val296. Biosynthetically prepared (E)-α-[3H]bisabolene was converted to todomatuic acid in induced grand fir cells, and the time course of appearance of bisabolene synthase mRNA was shown by Northern hybridization to lag behind that of mRNAs responsible for production of induced oleoresin monoterpenes. These results suggest that induced (E)-α-bisabolene biosynthesis constitutes part of a defense response targeted to insect herbivores, and possibly fungal pathogens, that is distinct from induced oleoresin monoterpene production.

Regulation of Oleoresinosis in Grand Fir (Abies grandis)1 : Differential Transcriptional Control of Monoterpene, Sesquiterpene, and Diterpene Synthase Genes in Response to Wounding

Grand fir (Abies grandis Lindl.) has been developed as a model system for the study of wound-induced oleoresinosis in conifers as a response to insect attack. Oleoresin is a roughly equal mixture of turpentine (85% monoterpenes [C10] and 15% sesquiterpenes [C15]) and rosin (diterpene [C20] resin acids) that acts to seal wounds and is toxic to both invading insects and their pathogenic fungal symbionts. The dynamic regulation of wound-induced oleoresin formation was studied over 29 d at the enzyme level by in vitro assay of the three classes of synthases directly responsible for the formation of monoterpenes, sesquiterpenes, and diterpenes from the corresponding C10, C15, and C20 prenyl diphosphate precursors, and at the gene level by RNA-blot hybridization using terpene synthase class-directed DNA probes. In overall appearance, the shapes of the time-course curves for all classes of synthase activities are similar, suggesting coordinate formation of all of the terpenoid types. However, closer inspection indicates that the monoterpene synthases arise earlier, as shown by an abbreviated time course over 6 to 48 h. RNA-blot analyses indicated that the genes for all three classes of enzymes are transcriptionally activated in response to wounding, with the monoterpene synthases up-regulated first (transcripts detectable 2 h after wounding), in agreement with the results of cell-free assays of monoterpene synthase activity, followed by the coordinately regulated sesquiterpene synthases and diterpene synthases (transcription beginning on d 3–4). The differential timing in the production of oleoresin components of this defense response is consistent with the immediate formation of monoterpenes to act as insect toxins and their later generation at solvent levels for the mobilization of resin acids responsible for wound sealing.

Anna Popovitch,In the Shadow of Althusser: Culture and Politics in Late Twentieth-Century Argentina, Ann Arbor, umi Dissertation Publishing, 2011, 238 páginas

Fil: Starcenbaum, Marcelo. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Instituto de Investigaciones en Humanidades y Ciencias Sociales (UNLP-CONICET); Argentina.

Note from William Croswell to President Kirkland and the Corporation of Harvard College, 1817-1821

This folder contains six documents: three drafts of a brief March 10, 1817, note to Harvard President John Kirkland, with two of the drafts followed by an October 25, 1819, note to the Harvard College Corporation concerning Croswell's work on Harvard's Library Catalogue.

Printed proposal for the works of Horace, 1821

This folder contains two copies of a proposal for publishing the works of Horace.

Payment order for Nathan Stone on behalf of his son, 1761 August 26

Handwritten order to John Sale to pay scholarship funds to Nathan Stone on behalf of his son Nathan Stone (Harvard AB 1762), signed by Thomas Foxcroft, Charles Chauncey, Thomas Waite, and Daniel Marsh.

Analysis of Luke 14, 1761 October

Two notebook sheets with handwritten summaries in English of Luke 14 beginning, "The contents of this chapter may be reduced to 5 General Division..." The document is a draft with edits and struck-through words, and is dated and signed "Boston, 1[9] October 1761. J. Belknap" with the note, "Read in the Chapel of Harvard College at Even'g Prayers Octob. 1761."

The Death of John the Baptist, [ca. 1761]

Four-page handwritten English composition containing a sketch of the death of John the Baptist beginning "John was imprisoned in the Castle of Machaerus..."

[College Declamation of Andrew Fuller, 1761]

One-page handwritten Latin composition by Andrew Fuller with an epitaph of two lines from Perseus beginning, "Respice quod non es..." The document is a draft with edits and struck-through words.

Notebook of Tristram Gilman, 1757-1761

The small volume holds the notebook of Tristram Gilman interleaved on unlined pages in a printed engagement calendar. The original leather cover accompanies the notebook, but is no longer attached. The inside covers of the original leather binding are filled with scribbled words and notes. The volume holds a variety of handwritten notes including account information, transcriptions of biblical passages and related observations, travel information, community news, weather, and astronomy. The volumes does not follow a chronological order, and instead seems to have been repurposed at various times.

Motion for change of venue in the case of the Inhabitants of Massachusetts Bay Colony v. Charles Paxton, October 1761

A motion that the case not be tried in Suffolk County, on the grounds that the judges and jurors were residents of the colony. Pratt was attorney to Paxton, an attorney and commissioner of customs, who had incurred a debt to the Colony.

Valedictory address of Stephen Hooper, 1761

Unattributed and undated handwritten Latin valedictory oration likely composed by graduate Stephen Hooper for the 1761 Harvard College Commencement. In the oration, Hooper praises Massachusetts Governor Francis Bernard, Thomas Hutchinson, Professor Edward Wigglesworth, and Tutor Belcher Hancock. The oration mentions classmate John Chipman (1745-1761) who died of illness on April 15, 1761.