Transgenic wheats with elevated levels of Dx5 and/or Dy10 high-molecular-weight glutenin subunits yield doughs with increased mixing strength and tolerance

To test the effects of independently increasing the in vivo levels of high-molecular-weight glutenin subunits (HMW-GS) Dx5 and Dy10 on wheat flour properties, we increased the copy numbers of their corresponding genes by genetic transformation. Thirteen transformants with increases in one or both subunits were chosen for biochemical and functional characterization by solvent fractionation, RP-HPLC, SDS-sedimentation, and micro-mixing. Increases in Dx5 and Dy10 contents ranged from 1.4- to 3.5-fold and 1.2- to 5.4-fold, respectively, and generally resulted in increased polymeric protein, increased mixing times and tolerances, and lower peak resistances. Increases in Dx5 content had larger effects on most parameters than comparable increases in Dy10. Flours with more than 2.6-times the native levels of Dx5 could not be mixed under standard 2-g mixograph conditions, while flours with 5.4 times the native levels of Dy10 could be mixed if sufficient time was allowed. Increases in Dx5 and Dy10 had additive effects on mixing behavior. These experiments demonstrate that dough mixing strength and tolerance can be increased by raising the levels of native HMW-GS Dx5 or Dy10, but that the effects of the two subunits are quantitatively and qualitatively different.     

Photoperiod manipulation for the reproductive management of captive wolffish populations: <Emphasis Type="Italic">Anarhichas minor</Emphasis> and <Emphasis Type="Italic">A. lupus</Emphasis>

This study provides new and practical information to implement the use of photoperiodic manipulation for the control of the sexual maturation of Canadian 6⁺ Atlantic wolffish (Anarhichas lupus) and 3⁺ first-time spawners spotted wolffish (Anarhichas minor) from Canadian and Norwegian populations. Wolffish reproductive cycle (gametogenesis and oocyte maturation and spermiation) was monitored for 23 consecutive months. Control groups were held under a 12-month simulated natural photoperiod and treatment groups under an 8-month compressed photoperiod. Plasma sex steroid concentrations (estradiol-17β and 11-ketotestosterone), oocyte diameter growth, and milt production were assessed monthly. For all groups under study, fish subjected to the compressed photoperiod spawned 2–6 months earlier than the controls. Complete out-of-shift cycle was not achieved based on the completion of two reproduction cycles, and this is briefly discussed. Photoperiod treatment induced temporal shifts in sex steroid profiles, which are the likely mediators of altered timing of ovulation/final maturation. Photoperiod has a strong influence on the timing of wolffish maturation and could be used as an efficient and inexpensive tool to secure wolffish reproduction operations (year-round supply of egg and milt and/or timing with optimal temperature regimes).