Fish use of ecohydraulic‐based mesohabitat units in a low‐gradient Illinois stream: implications for stream restoration

• 1. A classification scheme for ecohydraulic‐based mesohabitat units was developed for a summer low‐flow period. Mesohabitat unit designations were based on the integration of three‐dimensional channel hydraulics, geomorphic maintenance processes of bed morphology, and biological resource needs of fish. Ecological relevance of the units was evaluated by a study of fish mesohabitat use patterns, and species relationships to feeding guild. By portraying the stream as a mosaic of hydraulic habitat patches that provide specific biotic resource needs, this study's aim was to advance how ecological information may be incorporated into the stream restoration design process.
• 2. Nine mesohabitat units were designated, including pool‐front, ‐mid, and ‐rear units, scour pool, simple and complex riffles, glide, submerged point bar, and channel expansion marginal deadwater. Physical habitat structure differed among the nine mesohabitat units by length, water depth, and bed slope and complexity. Fish were collected in specific unit volumes by use of prepositioned areal electrofishing devices, in which distinct patterns of fish mesohabitat use were observed.
• 3. A key finding was the differences in fish assemblages among the pool units, in which fish densities were greatest in the pool‐front and scour pool units. Also, fish density in the pool‐front unit was positively correlated with pool entrance slope. Biomass was greatest in the pool‐front and ‐mid units, and it was correlated with maximum mid‐pool depth. Density and biomass were generally lowest in the pool‐rear unit. Other unique relationships were also observed among the mesohabitat units.
• 4. Based on feeding guild, patterns of fish mesohabitat use were observed for this summer low‐flow period; insectivores dominantly used pool‐front and scour pool units, herbivores dominantly used complex riffle units, and piscivores used pool‐front and ‐mid units.
• 5. Useful ecological information was derived from fish species‐habitat relationships observed in this study, linking mesohabitat units with species requirements for food resources. Such findings support advancements to ecological design strategies for stream restoration that promote hydraulic habitat diversity.

Copyright © 2008 John Wiley & Sons, Ltd.     

Changes in Distribution of Isoflavones and β‐Glucosidase Activity During Soy Bread Proofing and Baking

Bread made partially with soy may represent a viable alternative for increasing soy consumption in populations consuming Western diets. The potential health‐promoting activity of soy isoflavones may depend on their abundance and chemical form. The objective of this study was to characterize the changes in isoflavone distribution and β‐glucosidase activity during the soy breadmaking process. Soy bread ingredients were combined and mixed to form a dough that was subsequently proofed at 48°C for 1–4 hr and baked at 165°C for 50 min to produce breads. The isoflavone composition and β‐glucosidase activity in bread ingredients, doughs, and breads were monitored. Soy ingredients and wheat flour (not bread yeast) were the major contributors of the β‐glucosidase activity in bread. No degradation of isoflavones was observed during breadmaking but the isoflavone distribution was largely altered. Proofing and baking have important but different roles in changing the isoflavone distribution. Proofing converted isoflavone β‐glucosides to aglycones by highly specific β‐glucosidase activity. Thermal treatment during baking significantly decreased the isoflavone malonylglucosides and increased isoflavone β‐glucosides. Enzyme activity during proofing and the balance between formation and deconjugation of isoflavones during baking determine the isoflavone content and composition in the final product.