. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. WOOD DIGESTION IN THE SHIPWORM 305 0-20 TJ O c 0) <U O tn -O tn tn O w e S I 3 o. 12 Time 24 36 (hours) FIGURE 4. Production of soluble sugars by B. goiildi dialyzed homogenate from milled wood (squares) and a-Cellulose (circles). The substrate (ordinate) refers to mg carbohydrate in the substrate particles. Both glucose (closed symbols) and total reducing sugar (open symbols) production are shown. in these studies is about 70% carbohydrate (Dean, 1976) of which about 60% is native cellulose (Meier, 1964).
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. WOOD DIGESTION IN THE SHIPWORM 305 0-20 TJ O c 0) <U O tn -O tn tn O w e S I 3 o. 12 Time 24 36 (hours) FIGURE 4. Production of soluble sugars by B. goiildi dialyzed homogenate from milled wood (squares) and a-Cellulose (circles). The substrate (ordinate) refers to mg carbohydrate in the substrate particles. Both glucose (closed symbols) and total reducing sugar (open symbols) production are shown. in these studies is about 70% carbohydrate (Dean, 1976) of which about 60% is native cellulose (Meier, 1964). The observed rate of glucose production from this material by Bankia enzymes is consistent with the crystallinity of wood cellulose (Fig. 3A). The higher rate of total reducing sugar production from MW con- trasts with results for purified celluloses, where rates of reducing sugar and glucose production are identical, indicating glucose to be the major product. Removing the lignin fraction from wood greatly enhances the lability of MW to Bankia enzymes (Fig. 3B). If the hemicellulose fraction is extracted from the delignified wood, the a-cellulose residue shows greatly decreased lability, here ex- pressed as sugar production per mg carbohydrate in the substrate (Fig. 4). The Trichoderma preparation, on the other hand, showed activity on a-cellulose sub- stantially higher than that seen on MW. This a-cellulose residue consists of native crystalline cellulose and glucomannan hemicellulose (Browning, 1967). DISCUSSION Available evidence strongly suggests that wood makes an important contribution to the energy requirements of Bankia gonldi and other species of wood boring ship- worms. The ingestion of wood particles and the uniquely specialized digestive tract argue for an important role. The maintenance of large glycogen reserves (30% of dry tissue weight) in Lyrodns pediccUatns is dependent on a supply of wood. Please note that these images are extracted from scanned page images
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
