title: Evidence for a novel cryoprotective protein from freeze-tolerant larvae of the goldenrod gall fly Eurosta solidaginis.
abstract: Third-instar larvae of the goldenrod gall fly Eurosta solidaginis (Diptera: Tephritidae) from populations in northern North America transition from freeze-susceptible to freeze-tolerant just prior to the onset of winter. While studies have documented the accumulation of carbohydrate cryoprotectants during this transition, protein cryoprotectants common to other freeze-tolerant species have not been reported in the gall fly. Using larvae collected from a population in Madison County, NY, which changes from freeze-susceptible to freeze-tolerant in early October, we assayed for the presence of factors that could preserve the catalytic activity of the cold-labile enzyme, rabbit muscle lactate dehydrogenase. Freezing this enzyme with a heat-stable, hydrophilic fraction derived from homogenates of both freeze-tolerant larvae and those in the process of becoming freeze-tolerant preserved between 70% and 80% of this enzyme's activity. Neither a comparable solution of bovine serum albumin nor the naturally-occurring carbohydrates (glycerol, sorbitol, or trehalose) conferred this level of cryoprotection. The putative cryoprotective protein from gall fly larvae did not bind to a weak anion exchanger, implying that its character may be cationic.
authors.affiliation: Department of Biology, Colgate University, Hamilton, NY 13346, USA. npruitt@mail.colgate.edu
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Pruitt
authors.forename: Nasheed
authors.initials: N
authors.lastname: Moqueet
authors.forename: Craig A
authors.initials: CA
authors.lastname: Shapiro
mesh_terms: D000818:Animals; D003451:Cryoprotective Agents / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005615:Freezing; D019476:Insect Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D007814:Larva / Q000378:metabolism; D033621:Tephritidae / Q000254:growth & development*
chemical_list: D003451:Cryoprotective Agents; D019476:Insect Proteins