442
N. BALAKRISHNAN NALR AND M. SARASWATHY
bacteria. The bacteria themselves, the author suggests, may serve as
food. Bacteria play a role in the softening of submerged wood surfaces
which may make the wood more susceptible to attack by marine borers.
That cellulose is broken down by bacteria and not by enzymes has also
been suggested by Johnson (1949), while Deschamps (1953) questioned
the presence of an enzyme produced by the animal since he could not
distinguish the cellulase of bacterial origin from that produced by the
animal.
Nair (1955b, 1955c, 1956c, 1957b) investigated the nature and
properties of the enzymes in the style and the digestive diverticula of
Bankia indica. Wood particles are found in the caecum in a highly
disintegrated state along with reducing sugars. It was, therefore, inferred that the style may contain a cellulase. A suspension of regenerated cellulose was incubated with the enzyme extract and the
change in turbidity was measured colorimetrically (Nair, 1955~). A
marked decline in turbidity was observed in experimental tubes. This
test was confirmed by determining the cellulose left undigested. The
extent of digestion of cellulose was also verified by determining the
sugars formed in the reaction mixture according to the method of
Somogyi (1930). The amount of sugars formed at the end of the different incubation periods were also estimated. The path of cellulose
degradation was studied by chromatographing the hydrolysates and
determining qualitatively the end products of cellulase activity. Enzyme preparations from the digestive diverticula and from the style
were used. The substrate was either sawdust or regenerated filter paper.
The digestive mixtures were incubated at 30°C for 5 days and the
hydrolysates analysed at intervals. Rf values indicated the presence of
cellobiose and glucose in the active preparations, The hydrolysates
from the style showed the presence of both cellobiose and glucose at all
stages of hydrolysis (Nair, 1956e). From this it was presumed that the
style enzymes by themselves are incapable of hydrolysing cellulose completely into glucose and that part of the cellobiose is apparently hydrolysed later at some other site in the digestive tract. The extract of
the style of Bankia was found to be capable of hydrolysing glycogen and
also showed some activity on lactose and maltose (Nair, 1957b). The
stomach contents of Bankia have an average pH of 5.8 due to the
dissolution of the style which has a pH of 5.5. The optimum pH for the
activity of the enzymes of the style (pH 5.9) is about the same as that
of the stomach where these are active. The optimum duration of
hydrolysis is 5 h and the optimum temperature 31OC. The enzyme
system gets inactivated by heating for 15 min at 60°C. The enzymes of
the digestive diverticula comprise an effective carbohydrase enzyme
N. BALAKRISHNAN NALR AND M. SARASWATHY
bacteria. The bacteria themselves, the author suggests, may serve as
food. Bacteria play a role in the softening of submerged wood surfaces
which may make the wood more susceptible to attack by marine borers.
That cellulose is broken down by bacteria and not by enzymes has also
been suggested by Johnson (1949), while Deschamps (1953) questioned
the presence of an enzyme produced by the animal since he could not
distinguish the cellulase of bacterial origin from that produced by the
animal.
Nair (1955b, 1955c, 1956c, 1957b) investigated the nature and
properties of the enzymes in the style and the digestive diverticula of
Bankia indica. Wood particles are found in the caecum in a highly
disintegrated state along with reducing sugars. It was, therefore, inferred that the style may contain a cellulase. A suspension of regenerated cellulose was incubated with the enzyme extract and the
change in turbidity was measured colorimetrically (Nair, 1955~). A
marked decline in turbidity was observed in experimental tubes. This
test was confirmed by determining the cellulose left undigested. The
extent of digestion of cellulose was also verified by determining the
sugars formed in the reaction mixture according to the method of
Somogyi (1930). The amount of sugars formed at the end of the different incubation periods were also estimated. The path of cellulose
degradation was studied by chromatographing the hydrolysates and
determining qualitatively the end products of cellulase activity. Enzyme preparations from the digestive diverticula and from the style
were used. The substrate was either sawdust or regenerated filter paper.
The digestive mixtures were incubated at 30°C for 5 days and the
hydrolysates analysed at intervals. Rf values indicated the presence of
cellobiose and glucose in the active preparations, The hydrolysates
from the style showed the presence of both cellobiose and glucose at all
stages of hydrolysis (Nair, 1956e). From this it was presumed that the
style enzymes by themselves are incapable of hydrolysing cellulose completely into glucose and that part of the cellobiose is apparently hydrolysed later at some other site in the digestive tract. The extract of
the style of Bankia was found to be capable of hydrolysing glycogen and
also showed some activity on lactose and maltose (Nair, 1957b). The
stomach contents of Bankia have an average pH of 5.8 due to the
dissolution of the style which has a pH of 5.5. The optimum pH for the
activity of the enzymes of the style (pH 5.9) is about the same as that
of the stomach where these are active. The optimum duration of
hydrolysis is 5 h and the optimum temperature 31OC. The enzyme
system gets inactivated by heating for 15 min at 60°C. The enzymes of
the digestive diverticula comprise an effective carbohydrase enzyme