Solution Properties of Polysaccharides - American Chemical Society

8 Dilute Solution Properties of Streptococcus salivarius Levan and Its Hydrolysates 1

S. S. STIVALA and J. E. ZWEIG

Department of Chemistry and Chemical Engineering, Stevens Institute of Technology, Hoboken, N J 07030

Downloaded by CORNELL UNIV on June 3, 2017 | http://pubs.acs.org Publication Date: April 21, 1981 | doi: 10.1021/bk-1981-0150.ch008

J. EHRLICH Department of Oral Biology, College of Medicine and Dentistry of New Jersey, Newark, N J 07103

Levan is a polymer composed of D-fructofuranose units joined by β-2, 6 bonds (1) . Though it is found in plants (2), the levans of interest here are those obtained from the extracellular substance of cariogenic bacteria. The levans of bacterial o r i gin are branched through β - 2 , 1 bonds, Figure 1. Levan, includ ing dextrans (4) and mutans (5) , have been implicated in dental caries and periodontal diseases by virtue of their acidogenic ( 6 , 7 ) , adhesive (8), and antigenic (9) properties in the oral cavity. The β-2, 6 and β-2, 1 linkages in Streptococcus saliva rius levan was recently confirmed from chemical ionization mass spectroscopy (10). The molecular weights of the levans produced from various bacterial cultures vary from about 12-100 x 10 daltons, e.g., S. salivarius, 30-32 x 10 ; Bacillus subtilis, 25 x 10 ; Aerobacter levanicum from cell cultures, 17 x 10 ; Aerobacter levanicum from isolated enzymes, 40-67 x 10 ; Bacillus vugatus 50-100 χ 10 ( see reference 11 for key references). Though the molecu lar weights of these levans can be as high as 100 x 10 , Long, Stivala and Ehrlich (12) reported that the molecular weight of levan produced by S. salivarius depends on the pH of the growth media, with value as low as 10 obtained at pH = 5.7. The breakdown of levan occurs through levan hydrolase, which is present in the mixed salivary sediment or plaque suspension and results f i r s t in the release of fructose which may be ulti mately metabolized to organic acid (13). DaCosta and Gibbons (14) found that the hydrolase is an inducible enzyme since it is formed in broth containing levan, insulin or sucrose, but not in broth containing glucose or fructose. The streptocccus of plaque are believed to be responsible for the hydrolysis of levan (15) and since the bacteria can rapidly hydrolyze levan, it acts as storage polymer of carbohydrate which can be continually metabolized to organic acid (16). 6

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© 1981 American Chemical Society Brant; Solution Properties of Polysaccharides ACS Symposium Series; American Chemical Society: Washington, DC, 1981.


102

SOLUTION PROPERTIES

OF

POLYSACCHARIDES

I t has been s u g g e s t e d by Leach and c o - w o r k e r s ( 1 7 ) t h a t l e v a n m i g h t be as i m p o r t a n t as t h e more i n e r t d e x t r a n i n t h e c a r i e s p r o c e s s s i n c e l e v a n i s q u i t e l i a b l e t o be a t t a c k e d by t h e o r a l b a c t e r i a and on h y d r o l y s i s and s u b s e q u e n t c a t a b o l i s m p r o v i d e s a p r o l o n g e d a c i d h a b i t a t f o r t h e t o o t h . T h u s , l e v a n may s e r v e as s u b s t r a t e f o r p r o l o n g e d a c i d p r o d u c t i o n even i n t h e a b s e n c e o f exogenous s u c r o s e o r o t h e r s i m p l e d i e t a r y s u g a r s , as f o r e x a m p l e , when t h e h o s t i s a s l e e p o r n o t e a t i n g . Therefore, one may assume t h a t t h i s p o l y m e r p l a y s an i m p o r t a n t r o l e i n l o n g t e r m d e m i n e r a l i z a t i o n o f t h e t e e t h and i n l o n g t e r m e c o l o g i c a l r e g u l a t i o n v i a p l a q u e pH d e p r e s s i o n . S t i v a l a and c o - w o r k e r s ( 1 8 , 1 9 ) examined t h e k i n e t i c s o f t h e a c i d h y d r o l y s e s o f S. s a l i varius l e v a n under v a r i o u s c o n d i t i o n s o f pH and t e m p e r a t u r e . B a h a r y and S t i v a l a ( 2 0 ) s t u d i e d s t r u c t u r a l changes d u r i n g t h e a c i d h y d r o l y s i s o f t h i s l e v a n by o b s e r v i n g changes i n m o l e c u l a r w e i g h t and v i s c o s i t y c o n t i n u o u s l y i n t h e l i g h t s c a t t e r i n g c e l l and v i s c o m e t e r , r e s p e c t i v e l y . The s o l u t i o n p r o p e r t i e s o f n a t i v e S. s a l i v a r i u s l e v a n , i n c l u d i n g f r a c t i o n a t e d m o i e t i e s , were r e p o r t e d i n e a r l i e r p a p e r s by S t i v a l a and c o - w o r k e r s (JJ_, 20_, 2J_, 2 2 , 2 3 ) . A number o f p h y s i c o c h e m i c a l p a r a m e t e r s o f n a t i v e B. s u b t i l i s l e v a n , i n c l u d i n g t h e products from m i l d a c i d h y d r o l y s e s of molecular weights ranging f r o m 1 0 0 χ 106 t o a low o f s e v e r a l t h o u s a n d s , were r e p o r t e d by Dedonder and S i l c e w i c z (2k). T h i s p a p e r w i l l r e v i e w o u r e a r l i e r work on t h e s o l u t i o n p r o p e r t i e s o f S. s a l i v a r i u s l e v a n and e x t e n d o u r r e c e n t work ( 2 5 ) on t h e s o l u t i o n p r o p e r t i e s o f f r a c t i o n a t e d moieties of the a c i d hydrolyzed levan. M a t e r i a l s and Methods Materials. ( a ) . Levan P r e p a r a t i o n : Levan was p r e p a r e d and p u r i f i e d f r o m c u l t u r e s o f S. s a l i v a r i u s s t r a i n ATCC 1 3 4 1 9 a c c o r d ing t o p r o c e d u r e s d e s c r i b e d e l s e w h e r e ( 1 2 , 2 6 ) . ( b ) . A c i d Hydrolyses: N a t i v e l e v a n was h y d r o l y z e d a t pH % 2 a t 35°C a c c o r d ing t o p r o c e d u r e s d e s c r i b e d i n e a r l i e r p a p e r s ( 1 8 , 2 5 ) . (c). F r a c t i o n a t i o n : , The w a t e r s o l u b l e n a t i v e l e v a n was f r a c t i o n a t e d by f r a c t i o n a l e l u t i o n u s i n g v a r y i n g r a t i o s o f w a t e r / t e t r a h y d r o f u r a n ( 1 1 ) . The h y d r o l y z e d sample was f r a c t i o n a t e d by f r a c t i o n a l p r e c i p i t a t i o n a t a b o u t 4°C u s i n g e t h a n o l as n o n - s o l vent ( 2 5 , 2 7 ) . Methods. ( a ) . Molecular Weights: Weight-average molecular w e i g h t s , R , ( g r e a t e r t h a n a b o u t 5 x 1 0 4 ) were o b t a i n e d i n w a t e r and i n v a r i o u s s o l v e n t s , e . g . s a l i n e s o l u t i o n s , u r e a s o l u t i o n s , d i m e t h y l s u l f o x i d e , f r o m Zimm p l o t s u s i n g l i g h t s c a t t e r i n g d a t a ( 2 1 , 2 2 ) . S e d i m e n t a t i o n e q u i l i b r i u m was used t o o b t a i n M f o r samples o f R < 5 x (25, 27). Number-average m o l e c u l a r w e i g h t s , M , were o b t a i n e d f r o m c o l o r i m e t r i c data from end-group a n a l y s i s ( r e d u c i n g sugar) a c cording to procedure described e a r l i e r (19). w

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Brant; Solution Properties of Polysaccharides ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

8.

STIVALA E T A L .

S.

salivarius

103

Levan

(b). D i m e n s i o n a l P a r a m e t e r s : The z - a v e r a g e root-mean s q u a r e radii of gyration, (R2) , were c a l c u l a t e d from t h e Zimm p l o t s o f l i g h t s c a t t e r i n g , and s e d i m e n t i o n c o e f f i c i e n t s , S ° , were o b t a i n e d from s e d i m e n t a t i o n v e l o c i t y d a t a as d e s c r i b e d i n e a r l i e r p a p e r s ( 2 1 , 2 2 ) . ( c ) . I n t r i n s i c v i s c o s i t y , [η],and p a r t i a l s p e c i f i c volume, v: The [η] and ν were d e t e r m i n e d f r o m v i s c o s i t y and d e n s i t y measurements a c c o r d i n g t o p r o c e d u r e s d e s c r i b e d e a r l i e r

(11, 21).


Di s c u s s i o n I. S o l u t i o n P a r a m e t e r s o f U n h y d r o l y z e d L e v a n . The f r a c t i o n a l e l u t i o n o f t h e n a t i v e l e v a n r e p o r t e d by E h r l i c h and c o - w o r k e r s (11) p r o d u c e d a t o t a l o f 20 f r a c t i o n s w i t h t h e 2 0 t h f r a c t i o n r e c o v e r e d a t 54/46 hLQ/THF. T u r b i d i m e t r i c t i t r a t i o n showed t h a t more t h a n o n e - h a l f o r t h e l e v a n i s e x t r a c t e d i n t h e n a r r o w range o f 50/50 t o 53/47 H 0/THF. The [η], M , S ° , ν and (R2) r e p o r t e d by S t i v a l a and c o - w o r k e r s (JJ_, 2J_) f o r some o f t h e f r a c t i o n s a r e summarized i n T a b l e I below. These i n v e s t i g a t o r s o b t a i n e d v a l u e s o f 0.17 and 0.62 f o r t h e e x p o n e n t s o f t h e l i n e a r d o u b l e l o g a r i t h m i c p l o t s o f [η] vs. M and S° vs. M , r e s p e c t i v e l y . Exponent v a l u e s o f 0.5 t o 0 . 9 i n t h e f o r m e r p l o t a r e e x h i b i t e d by random c o i l s whereas v a l u e s below 0.5 and 2.0 i n d i c a t e b r a n c h ed s t r u c t u r e s and r o d s , r e s p e c t i v e l y . Exponent v a l u e s o f 0.57, 0.62, 0.71 f o r b r a n c h e d s t r u c t u r e s , 0.20, 0.29, 0.33 f o r r o d s , and 0.41, 0.43 and 0.47 f o r l i n e a r shapes have been r e p o r t e d from s l o p e s o f t h e l a t t e r p l o t ( 2 1 ) , whereas 0.67 i s e x p e c t e d t o r s p h e r e s . A v a l u e o f 0.43 was o b t a i n e d (21) f r o m t h e s l o p e o f t h e l o g - l o g p l o t o f (R2) vs. M . For l i n e a r polymers v a l u e s o f 0.5-0.6 have been r e p o r t e d and f o r s p h e r e s t h e (R2) v a r i e s w i t h M1/3. 2

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9

Table

I . S o l u t i o n P a r a m e t e r s o f S. s a l i v a r i u s Levan 25°C ( 2 2 ) .

Fraction F12 F14 F15 F17

[η] ( d l / g ) 0.144 0.148 0.149

M X w 10~

SO 6

18.5 20.0

Χ 10

(sec)

1 3

v(ml/g)

z

i n H«0 a t (R?) 9 ζ (A)

200 194

0.66

333

0.63

195

0.62 0.64

340 349 403 493 410 803

0.151

17.4 19.0

F18 F19

0.153 0.156

29.7

182 232

32.5

299

F20

0.183

57.1

387

0.63 0.61 0.63

ΒI0P0LYMERS, T a b l e I I


104

SOLUTION PROPERTIES OF

POLYSACCHARIDES

The v a l u e s o f [η] shown i n T a b l e 1 a r e e x t r e m e l y low f o r such e x t r e m e l y h i g h m o l e c u l a r weight macromolecules. Further, i t i s n o t e d t h a t t h e s e h i g h m o l e c u l a r w e i g h t f r a c t i o n s have c o r r e s p o n d i n g low r a d i i o f g y r a t i o n . Based on t h e s e o b s e r v a t i o n s and on t h e v a l u e s o f t h e e x p o n e n t s o f t h e l o g - l o g p l o t s o f [η]-, SO-,and ( R 2 ) % - M. n a t i v e S. s a l i v a r i u s l e v a n i s b e s t d e s c r i b e d as a h i g h l y b r a n c h e d , compact s t r u c t u r e o f n e a r - s p h e r i c a l sym m e t r y ( 1 1 , 2 1 ) . T h i s i s i n agreement w i t h t h e e l e c t r o n m i c r o g r a p h s t u d i e s o f Newbj-un and c o - w o r k e r s ( 2 8 ) . The [η] and ( R ^ ) ^ f t n a t i v e l e v a n and i t s f r a c t i o n s were f o u n d ( 2 2 ) t o 8 e s i g n i f i c a n t l y h i g h e r i n d i m e t h y l s u l f o x i d e t h a n i n w a t e r , r e f l e c t i n g t h e h i g h e r h y d r o d y n a m i c volume o f l e v a n in the former. The [η], ( R ^ ) ^ and M were a l s o o b t a i n e d i n o t h e r s o l v e n t s ( 2 3 ) , e.g., oA - 0 . 4 Ν NaCl , 4 - 8 M u r e a , e t h a n o l H2O 1 1 / 9 by v o l u m e . The M were c o n s t a n t , w i t h i n experimental e r r o r , i n d i c a t i n g t h a t t h e l e v a n i n w a t e r i s n o t a g g r e g a t e d by h y d r o g e n bonds. V a l u e s o f t h e r a d i i o f g y r a t i o n were l o w e r i n w a t e r t h a n i n aqueous s o l u t i o n s o f u r e a and l o w e s t i n t h e ethanol/water mixture. In t h e f o r m e r , u r e a may b r e a k i n t r a m o l e c u l a r h y d r o g e n b o n d s , e.g., between b r a n c h e s , a l l o w i n g t h e m o l e c u l e t o expand w h e r e a s i n t h e l a t t e r , t h e e t h a n o l , b e i n g a p r e c i p i t a n t , r e n d e r s t h e e t h a n o l / w a t e r m i x t u r e a poor s o l v e n t c a u s i n g the m o l e c u l e t o c o n t r a c t . Q

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I I . S o l u t i o n Parameters of Hydrolyzed Levan. The h y d r o l y s i s of n a t i v e levan e f f e c t e d a reduction in M f r o m 4 3 x 10& t o 5 . 5 x 1 0 ^ d a l t o n s . The f r a c t i o n a t i o n o f t h e p a r t i a l l y h y d r o l y z e d l e v a n y i e l d e d 32 f r a c t i o n s v a r y i n g i n R f r o m 8 _ x 106 down t o _ 1 0 (25, 27). D o u b l e l o g a r i t h m i c p l o t s o f [η] vs. M and S° vs. M e a c h y i e l d e d two l i n e a r segments i n t e r s e c t i n g a t M % 1 0 ^ . The e x p o n e n t s o f t h e f o r m e r w e r e 0.05 and 0 . 6 7 f o r M i n the range o f 8 χ ΙΟ** t o 2 χ 1 θ 5 and 9 χ 1 0 ^ t o 1 0 * , r e s p e c t i v e l y , w h e r e a s t h o s e o f t h e l a t t e r were 0 . 6 7 and 0 . 4 3 , r e s p e c t i v e l y . Examina t i o n o f the v a l u e s of these exponents suggested t h a t the levan hydrolysates of R > 10^ a r e b e s t c h a r a c t e r i z e d by s p h e r e s and those of M < 1 θ 5 e x h i b i t random c o i l b e h a v i o r ( 2 5 , 2 7 ) . Cal c u l a t i o n s , b a s e d on e q u i v a l e n t s p h e r e s and random c o i l s , o f v a r i o u s d i m e n s i o n a l p a r a m e t e r s f r o m [η], S°, and f r i c t i o n a l c o e f f i c i e n t data confirmed t h i s observation ( 2 5 ) . w

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T a b l e II c o n t a i n s v a l u e s o f M f o r the levan h y d r o l y s a t e s o b t a i n e d f r o m e n d - g r o u p s a n a l y s e s , and s e d i m e n d a t i o n e q u i l i b r i u m . V a l u e s by t h e two methods a r e , w i t h i n e x p e r i m e n t a l e r r o r , i n good a g r e e m e n t . F i g u r e 2 shows t h e p l o t o f l o g [η] vs. l o g M (values of [η] f r o m r e f e r e n c e _25) o f t h e l e v a n h y d r o l y s a t e s f o r [η] measured in w a t e r a t 25°C. I t i s noted from t h i s f i g u r e , t h a t t h e r e a r e two l i n e a r s e g m e n t s . The 1 i n e a r segments can be e x p r e s s e d by t h e M a r k - H o u w i n k e q u a t i o n , [η] = Κ where t h e e x p o n e n t α i s o b t a i n ed f r o m t h e s l o p e . The e x p o n e n t s c a l c u l a t e d f r o m F i g u r e 2 a r e 0 . 5 0 f o r levan hydrolysates of M < 4 χ 10^ and 0 . 1 1 f o r v a l u e s n

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STIVALA ET AL.

S. salivarius Levan


8.


105

106

SOLUTION

Table

II.

PROPERTIES OF

POLYSACCHARIDES

Number-Average M o l e c u l a r W e i g h t s o f Levan Ν

Sample

Hydrolysates

3

Sample

η

M

3

M

B

η 2.06x10

F17

3.36x1ο *

F19 F21

3.33

E7

2.06

6.21

E6

1.Ί6

1.56

F13

3.51

E5

9.47x10^

9.98x10

F15

it.62

Ek

3.68

1.93

Native F1

2.27

F5 F7

1.45 6.63x10

F10

5

k

1

2.80 1.86x10** , 3


Determined from end-group a n a l y s i s ^Determined from s e d i m e n t a t i o n e q u i l i b r i u m 4

of M > 4 χ 10 . The n a t u r e o f F i g u r e 2 r e f l e c t t h e o b s e r v a t i o n s made f r o m s i m i l a r p l o t s u s i n g M v a l u e s ( 2 5 ) . However, as ment i o n e d e a r l i e r _ t h e v a l u e s o f α i n t h i s c a s e was 0 . 0 5 f o r M > 10^ and 0 ^ 6 7 f o r ^ M ^ < 1 0 ^ . The d i f f e r e n c e i n v a l u e s o f α o b t a i n e d from M and M o f t h e l e v a n h y d r o l y s a t e s r e f l e c t t h e p o l y d i s p e r s i t y o f t h e s a m p l e s i n t h e w e i g h t r a n g e e x a m i n e d . The two d i f e r ent s l o p e s observed i n . F i g u r e 2 i n d i c a t e s t h a t the s t r u c t u r e of levan hydrolysates of M < 4 χ 1 0 ^ and M > 4 X 10^ are d i f f e r e n t . The d i s p e r s i t i e s , M /M , o f n a t i v e l e v a n and h y d r o l y s a t e s a r e s u m m a r i z e d i n T a b l e I I I |R v a l u e s are from r e f e r e n c e 2 5 ) . The h y d r o l y s i s o f t h e n a t i v e l e v a n e f f e c t e d an a p p r e c i a b l e d r o p i n d i s p e r s i t y f r o m 2 0 7 t o v a l u e s b e l o w 3 6 d e p e n d i n g on t h e m o l e c u l a r weight o f the h y d r o l y s a t e . As a g r o u p , h y d r o l y s a t e f r a c t i o n s o f M > 4 χ 10^ e x h i b i t d i s p e r s i t i e s i n t h e range o f 3 6 - 5 . 4 w h e r e a s tnose of M < k χ 10** have l o w e r d i s p e r s i t i e s i n t h e n a r r o w e r range o f 2 . 7 - 1 . 3 . F i g u r e 3 shows w

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W

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Table

III.

D i s p e r s i t y , M /M

Sample

w

η

o f N a t i v e Levan and Sample

Its M

w

207

F17

6.5

F1

36

F19

2.7

F5

2k

E7

1.3

F7

31

E6

1.5

F10

13

E5

1.9

F13

10

Ek

2.7

F15

5.k

Native

Levan

/M

Hydrolysates

η

the l o g - l o g p l o t o f M vs. M . I t i s n o t e d t h a t t h e two l i n e a r c u r v e s o f d i f f e r e n t s ? o p e s r e f l e c t t h e two s t r u c t u r a l l y d i f f e r e n t levan h y d r o l y s a t e s .


AL.

S. salivarius

Levan


STIVALA E T


SOLUTION

108

PROPERTIES

O F POLYSACCHARIDES

Exponent values of 0 . 0 5 and 0 . 6 7 of the Mark-Houwink rela tion for hydrolysates of M > 1 0 and M < 1 θ 5 . respectively, suggest that the former behave as spheres and the latter as ran dom coils. The diameter, d, of hard sphere suspended in a liquid medium, may be calculated from [η] using the Einstein equation, [η] = 2.5/p where ρ is the density of the sphere; i.e., ρ = m/v = m/(l/6) π d3 where m is mass and ν is the volume. Since m = M/N where M is molecular weight and Ν is Avogadro's number, the exp ression for d in terms of the measured M and [η] is p

w

d = [M[n]/(2.5)(l/6)irN]

(1)

1/3


_2 The mean square end-to-end distance, r , for random coil may be calculated from [η] and M using the Flory-Fox equation [η]

= Φ (r ) /M 2

(2)

3/2

2

οι

where Φ = 2 . 5 x 10 . Using equations ( 1 ) and (2) the R for sphere and random coil may be calculated from the relationships R2= ( 3 / 2 0 ) d and R = r / 6 , respectively. Thus, Stivala and cow8rkers ( 2 5 ) , calculated the values of R^ for the hydrolysates and from their corresponding values of M^, obtained the following relationships from log-log plots, 2

2

2

(R )* = 0 . 8 2 Μ ° ·

5

(3)

"Τ J- °· 7 ς (R ) = 0.13 M for Μ < 10 g w w

(4)

2

3 6

for M > 1 0

5

2

ρ

The exponent value of 0.36 is in good agreement with 0.33 for spheres, and the exponent value of 0.57 is in good agreement with 0.5-0.6 for random coils. Regarding native S. s a l i v a r i u s levan, Stivala and co-workers C M , 2J_) reported that in water it behaves as a highly branched compact structure of spherical symmetry. The hydrolytic degradation of levan is catalyzed by the enzyme levan hydrolase which is found in the mixed salivary sedi ment or plaque suspension. DaCosta and Gibbons (14) reported that the enzyme preferentially cleaves the terminal fructose units suggesting that the hydrolysis is non-random. Stivala, Lauren and co-workers (18, 20) examined the_acid hydrolysis of S. saliv arius levan by observing changes in M and [η] continuously as a function of time, temperature, pH, and levan concentration. Two simultaneous first-order reactions were observed, an initial rapid reaction attributed to 3-2,1 branch point cleavage and a slower reaction attributed to the 3-2,6 non-branch points in the mainchain and branches. Specific rate constants for the two processes were obtained from Guggenheim plots. These studies suggested that the hydrolysis of levan proceeds by a non-random process. w


8.

STIVALA E T A L .

S. salivarius

109

Levan

T h i s o b s e r v a t i o n was s u p p o r t e d f r o m changes i n M o b s e r v e d d u r i n g h y d r o l y s e s (19) w i t h s u b s e q u e n t a n a l y s i s o f t h e 9 a t a on a s t a t i s t i c a l model o f a t r i f u n c t i o n a l l y b r a n c h e d p o l y m e r . I t was o b s e r v e d t h a t t h e d i s p e r s i t y as a f u n c t i o n o f h y d r o l y s i s t i m e , f o r g i v e n t e m p e r a t u r e and pH, e x h i b i t s a maximum. No maximum was observed f o r dextran h y d r o l y s e s , which i s reported t o f o l l o w a random p a t h . I t i s c l e a r t h a t h y d r o l y t i c a t t a c k o f S. s a l i v a r i u s l e v a n p r o d u c e s two s t r u c t u r a l l y d i f f e r e n t d e g r a d a t i o n p r o d u c t s , one t h a t conforms t o b e h a v i o r i n s o l u t i o n c h a r a c t e r i s t i c o f spheres and t h e o t h e r c h a r a c t e r i s t i c o f random c o i l s . I t s h o u l d be m e n t i o n e d t h a t s o l u t i o n p r o p e r t i e s a r e g r e a t l y a f f e c t e d by t h e p r e s e n c e o f even a few l o n g b r a n c h e s b u t i n s e n s i t i v e t o many short branches. In t h i s c o n n e c t i o n i t was shown f r o m 3 ς NMR s p e c t r o s c o p y t h a t t h e s p e c t r a o f t h e h i g h v s . low m o l e c u l a r w e i g h t l e v a n h y d r o l y s a t e s do n o t d i f f e r (27) s u g g e s t i n g p e r h a p s t h e p r e s e n c e o f s h o r t b r a n c h e s i n t h e samples o f M < 10^ o r M < k χ


1

w

n

It i s noteworthy t o mention, i n support o f the o b s e r v a t i o n i n F i g u r e 2 on S. s a l i v a r i u s l e v a n , t h e work o f Dedonder and S l i z e w i c z (2k). These i n v e s t i g a t o r s examined t h e f r a c t i o n s o f t h e p a r t i a l l y a c i d h y d r o l y z e d 5. s u b t i l i s l e v a n . They r e p o r t e d t h a t a s i g n i f i c a n t change i n t h e s t r u c t u r e o f t h i s l e v a n o c c u r s following hydrolysis. Literature

Cited

1.

Whistler, R.L.; and Smart, C.L.; "Polysaccharide Chemistry"; Academic Press, New York, 1953; pp. 268-270. 2. Greenwood, C.T.; "Advanced Carbohydrate Chemistry"; 1952; 7, pp. 289-292. 3. Avigad, G.; "Encyclopedia of Polymer Science and Technology"; 1968; 8, pp. 711-718. 4. Sidebotham, R.L.;"Advan. Carbohydr. Chem."; 1974; pp. 371-444. 5. Guggenheim, B.; Helv. Odontol. Acta; 1970; 14, Suppl. V, 89108. 6. Manly, R.S.; and Richardson, D.T.; J. Den. Res.; 1968; 47, 1080-1086. 7. Bahn, A.N.; Cummings, S.G.; and Hayashi, J.S.; Dent. Res.; 1976; 55, Special Issue C, C134-C138. 8. de Stoppelaar, J.; Konig, K.G.; Plasschaert, A.J.M.; and van der Hoeven, J.S.; Arch, Oral. Biol.; 1971; 16, 971-975. 9. Shilo, M.; and Wolman, B.; Br. J. Exp. Pathol.; 1958; 39, 652-661. 10. Hancock, R.A.; Marshall, K.; and Weigel, H.; Carbohydrate Res.; 1976; 49, 351-360. 11. Ehrlich, J.; Stivala, S.S.; Bahary, W.S.; Garg, S.K.; Long, L.W.; and Newbrun, E.; J. Dental Res.; 1975; 54, 290-297. 12. Long, L.W.; Stivala, S.S.; and Ehrlich, J.; Arch. Oral Biol.; 1975; 20, 503-507.


SOLUTION PROPERTIES O F POLYSACCHARIDES

110

13. 14.

Manly, R.S.; and Dain, J.Α.; 1963; Proc. Int. Assoc. Dent. Res. Abstr: No. 359. DaCosta, T.; and Gibbons, R.; Arch. Oral Biol.: 1968; 13,

15.

van Houte, J.; and Jansen, H.M.; Arch. Oral Biol.:

609-617.

1968; 13,

827.

16. 17. 18.

Gibbons, R.J.; Caries Res.: 1968; 2, 164. Leach, S.A.; Kolendo, A.B.; and Saxton, C.A.; Caries Res.: 1967; 1, 104. Lauren, M.D.; Stivala, S.S.; Bahary, W.S.; and Long, L.W.;

19.

Stivala,

Biopolymers; 1975; 14, 2373-2385. 20,

20.

Bahary, W.S.; and Stivala,


1978;

21. 22.

S.S.; Lauren, M.D.; and Garg, S.K.; Polymer; 1979,

18-22. 63,

S.S.; Colloid and Interface Sci.;

212-217.

Stivala, S.S.; Bahary, W.B.; Long, L.W.; Ehrlich, J.; and Newbrun, E.; Biopolymers; 1975; 14, 1283-1292. Bahary, W.S.; Stivala, S.S.; Newbrun, E.; and Ehrlich, J., Biopolymers; 1975; 14, 2467-2478.

23.

Stivala,

S.S.; Bahary, W.B.; Carbohydrate Res.; 1978; 67,

17-21.

24.

Dedonder, R.; Slicewicz, 40,

25. 26. 27.

28.

P.; Bull. Soc. Chim. Biol.; 1958;

873-886.

Stivala, S.S.; Zweig, J.Ε.; Biopolymers; in press. Newbrun, E.; Baker, S.; Carbohydrate Res.; 1968; 6, 165-170. Zweig, J.Ε.; "The Physico-Chemical Characterization of Acid Hydrolyzed S. salivarius Levan"; 1977; Ph.D. Dissertation: Stevens Institute of Technology, Hoboken, N.J. Newbrun, E.; Lacy, R.; and Christie, T.M.; Arch. Oral. Biol.; 1971 ;

102,

549-558.

RECEIVED August 26,1980.


Solution Properties of Polysaccharides - American Chemical Society

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