- Email: [email protected]
‘Molecular’ and ‘molecules’
84
TIBS 1 3 - March 1988
Letters Ugnin degradation The recent article on lignin degradation by Prince and StiefeP in the September issue of TIBS gives an overview of the present understanding of white-rot lignin degradation. However, several points could be enlarged in order to clarify understanding of the function of the ligninolytic enzymes (lignin peroxidases) and the nature of the ligninolytic system of these organisms. Although lignin is an 'abundant resource for organisms able to metabolize it', no organism, so far, has been found to be able to gain net energy from fignin degradation or to use lignin as a sole carbon source. Moreover, lignin degradation by white-rot fungi is probably not associated with 'asexual spores' although these do adsorb lignin peroxidases. Cytochemical staining methods have shown that lignin peroxidase production is associated with the fungal hyphae2. 3. The mechanism of lignin degradation by actinomycetes is presently not known but would appear not to be analogous to white-rot degradation 4. The main effect by these bacteria is lignin solubilization and not its rapid degradation to carbon dioxide. Generally, molecular oxygen reacts with cation radicals very slowly, if at all. Radical cations are more readily convened to radicals (proton loss, CQ--Cpcleavage, addition of water) which subsequently react rapidly with oxygen. Umezawa and Higuchi 5 did not use a 'diphenolic' but a dimeric model compound and veratryl alcohol is not monophenolic. Indeed lignin peroxidase is unique in its ability to oxidize nonphenolic aromatic compounds. The aromatic ,;ng opening has already been demonstrated in a lignin peroxidasecatalysed reaction 6. This occurs only in the presence of molecular oxygen 7 and is connected to oxygen activation 8. Ring opening by laccases has, to our knowledge, not been shown. Finally one should emphasize that in vitro in an aqueous environment lignin is polymerized by the lignin peroxidase 9. To degrade lignin the white-rot fungi have a way to prevent polymerization by a mechanism that is presently not very well understood. It may be that low molecular weight degradation products are rapidly metabolized by the ~angus
which is one possible way to shift the equilibrium from spontaneous polymerization to degradation. Refereuces 1 Prince, R. C. and Stiefel, E. I. (1987) Trends Biochem. Sci. 12,334-335 2 Messner, K., Srebotnik, E., Ertler, G,, Foisner, R., Pettersson, B. and Stachelberger, H. (1987) Proc. Int. Symp on Lignin Enzymic and Microbial Degradation, Paris 23-24 April, pp. 243-248 3 Garcia, S., Latge, J. P., Prevost, M. C. and Leisola, M. (1987) Proc. Int. Symp. on Lignin Enzymic and Microbial Degradation, Paris 2324April, pp. 271-274 4 McCarthy, A. U. (1987) FEMS Microbiol. Rev. 46,145-163 5 Umezawa, T. and Higuchi, T. (1985) FEBS Lett. 182,257-259
6 Leisola, M. S. A., Schmidt, B., Thanei-Wyss, U. and Fiechter, A. (1985) FEBS Lett. 189, 267-270 7 Miki, K., Renganathan, V., Mayfield, M. B. and Gold M. H. (1987) FEBS Lett. 210, 199203 8 Haemmerli, S. D., Sehoemaker, H. E., Sehmidt, H. W. H. and Leisola, M. S. A. (1987) FEBS Lett. 220,149-154 9 Haemmerli, S. D., Leisola, M. S. A. and Fiechter, A. (1986) FEMS Microbiol. Lett. 53, 33--36
MATFI S.A. LEISOLA
Swiss Federal Institute of Technology, CH-8093 Zfidch, Switzerland. HANSE. SCHOEMAKER DSM Research, 6160 MD Geleen, The Netherlands.
'Molecular' and 'molecules' I read in the recent book review written by Victor D. Vacquier (TIBS 12, p. 381): • . . "There is very little ;molecular' (i.e. cloned genes) work described"... Vacquier has used quotation marks; I would still be interested to know how he defines 'molecules'. How is it that 'molecular', applied to biology, is still
being used (and has so often been used in the past) by authors to describe only their own approach to biology?
CLAUDELII~BECO Universitd de Liege, Quai Marcellis, 14/011, B-4020 Liege, Belgium.
TIBS Editorial Policy The Editors of TIBS wish to make it known that articles for t h i s journal are generally commissioned. Prospective authors who have not been asked to write should first approach a member of the board, or the Staff Editor in Cambridge, with a brief outline of the proposed article including a few key references. The Editor will decide whether to commission the proposed article. Authors should note that al/manuscripts are subject to peer review, and commissioning does not automatically guarantee publication.
TIBS 13- March 1988
"rIBS
85
puzzle compiledby Naomi G. Lipsky
Guess the word from the definition provided and write i t over the numbered dashes. Transfer each letter to the corresponding numbered square in the pattern. A black square indicates a word ending, and two indicate the end of a sentence. Any word may be continued on the next line of the pattern. The finished pattern will contain a quotation from the work of a scientist. The first letters of the guessed words will form an acrostic giving the author's name and the title of the work. All entries will be opened on 1 June 1988. The sender of the first correct entry opened will receive a one-year free subscription to TIBS. Send your answers to: TIBS, Elsevier Publications Cambridge, 68 Hills Road, Cambndge CB2 1LA, UK.
16
C 17
H 18
A 19
D
38
L }9
C r'0
P /41
H
~9 AA
~2
L 53
A 6/4
Z 65
K
G
3~ W
37 AA
B8
3 89
K
103 E 10~ F1105 W
106 R
l
130 N
1~3 D 13/4 O 135 P 136 0
153 H
157 A 158 N 159 I
D
13
}0 R 31 J) ~2 B
55
8
J9
F 10
B256
78
~- 79
101 I
G
P 30
HI81
125 ..1 126 C 127 F
149 J 150 W 151 01152 E
173 H 17~ BI175 V i
1
l
II
110 0 ~
-
112 L
180 U 181 O 182 P 18} J
I
A. Achieves funding continuance
B. Rockwaste C. e,g.y-- rex+ b D. Sourceofpudnes and pyrimidines
E. Excskeleton matedal
18 63 47 94 157 187
148695
115 85 32 174 131
16 39 52 68 142 126 163 171
N. 2sidesofa right triangle O. Disconnected from computer (2) P. Uke factodzation into primes Q. Orthorhombic, lead sulpharsanite mineral
29 10 181 108 77 133 155 . . . . . . 78 33 11 103 91 152
R. Smallest mammals S.
F. Lossof speech G. Saltof Dowexor Duolite
Intersection of radius, ulna, and humerus
37 9 104 86 127 165 179 T.
i = V/R (2)
4 14 49 110 43 136 151
40 19 19 135 79 117 182
25 134 74 154 45 50 144 67 106 51 120 30 177
7 15 118 162 99
13 93 178 42 119 124 70
12 98 137 81 56 16834 186 U. Metallic element
H. Vitamin B1
92 130 53 73 158 114 20
3 28 61 169 100 180
96 146 71 17 173 41 122 160
V. An opiate I. Grounds
111 101 1597235 60 W. Fourscore
J. Subject for Pasteur (2) K. Bend waves mound edge L. Unesofequalwind speed
~ ~ ~50 s7 165
s 31 102 125 149 69 183 167
6 121 23 89 154 147 65 44
6-"2 11'~ 2 13"--'2"140 38 17F~ 82
X.
Sitesforfemurs
Y.
Perennial, beloved of Apollo
Z.
Individual's life history
138 97 26 128 58 1!~
24 54 84 48 172 109 141 156
M. Switches to alternate route
95 54 80 21 153 69
AA. Afresh (2)
~ 5"9 8-'7 116 129 184
TIBS 1 3 - March 1988
Letters Ugnin degradation The recent article on lignin degradation by Prince and StiefeP in the September issue of TIBS gives an overview of the present understanding of white-rot lignin degradation. However, several points could be enlarged in order to clarify understanding of the function of the ligninolytic enzymes (lignin peroxidases) and the nature of the ligninolytic system of these organisms. Although lignin is an 'abundant resource for organisms able to metabolize it', no organism, so far, has been found to be able to gain net energy from fignin degradation or to use lignin as a sole carbon source. Moreover, lignin degradation by white-rot fungi is probably not associated with 'asexual spores' although these do adsorb lignin peroxidases. Cytochemical staining methods have shown that lignin peroxidase production is associated with the fungal hyphae2. 3. The mechanism of lignin degradation by actinomycetes is presently not known but would appear not to be analogous to white-rot degradation 4. The main effect by these bacteria is lignin solubilization and not its rapid degradation to carbon dioxide. Generally, molecular oxygen reacts with cation radicals very slowly, if at all. Radical cations are more readily convened to radicals (proton loss, CQ--Cpcleavage, addition of water) which subsequently react rapidly with oxygen. Umezawa and Higuchi 5 did not use a 'diphenolic' but a dimeric model compound and veratryl alcohol is not monophenolic. Indeed lignin peroxidase is unique in its ability to oxidize nonphenolic aromatic compounds. The aromatic ,;ng opening has already been demonstrated in a lignin peroxidasecatalysed reaction 6. This occurs only in the presence of molecular oxygen 7 and is connected to oxygen activation 8. Ring opening by laccases has, to our knowledge, not been shown. Finally one should emphasize that in vitro in an aqueous environment lignin is polymerized by the lignin peroxidase 9. To degrade lignin the white-rot fungi have a way to prevent polymerization by a mechanism that is presently not very well understood. It may be that low molecular weight degradation products are rapidly metabolized by the ~angus
which is one possible way to shift the equilibrium from spontaneous polymerization to degradation. Refereuces 1 Prince, R. C. and Stiefel, E. I. (1987) Trends Biochem. Sci. 12,334-335 2 Messner, K., Srebotnik, E., Ertler, G,, Foisner, R., Pettersson, B. and Stachelberger, H. (1987) Proc. Int. Symp on Lignin Enzymic and Microbial Degradation, Paris 23-24 April, pp. 243-248 3 Garcia, S., Latge, J. P., Prevost, M. C. and Leisola, M. (1987) Proc. Int. Symp. on Lignin Enzymic and Microbial Degradation, Paris 2324April, pp. 271-274 4 McCarthy, A. U. (1987) FEMS Microbiol. Rev. 46,145-163 5 Umezawa, T. and Higuchi, T. (1985) FEBS Lett. 182,257-259
6 Leisola, M. S. A., Schmidt, B., Thanei-Wyss, U. and Fiechter, A. (1985) FEBS Lett. 189, 267-270 7 Miki, K., Renganathan, V., Mayfield, M. B. and Gold M. H. (1987) FEBS Lett. 210, 199203 8 Haemmerli, S. D., Sehoemaker, H. E., Sehmidt, H. W. H. and Leisola, M. S. A. (1987) FEBS Lett. 220,149-154 9 Haemmerli, S. D., Leisola, M. S. A. and Fiechter, A. (1986) FEMS Microbiol. Lett. 53, 33--36
MATFI S.A. LEISOLA
Swiss Federal Institute of Technology, CH-8093 Zfidch, Switzerland. HANSE. SCHOEMAKER DSM Research, 6160 MD Geleen, The Netherlands.
'Molecular' and 'molecules' I read in the recent book review written by Victor D. Vacquier (TIBS 12, p. 381): • . . "There is very little ;molecular' (i.e. cloned genes) work described"... Vacquier has used quotation marks; I would still be interested to know how he defines 'molecules'. How is it that 'molecular', applied to biology, is still
being used (and has so often been used in the past) by authors to describe only their own approach to biology?
CLAUDELII~BECO Universitd de Liege, Quai Marcellis, 14/011, B-4020 Liege, Belgium.
TIBS Editorial Policy The Editors of TIBS wish to make it known that articles for t h i s journal are generally commissioned. Prospective authors who have not been asked to write should first approach a member of the board, or the Staff Editor in Cambridge, with a brief outline of the proposed article including a few key references. The Editor will decide whether to commission the proposed article. Authors should note that al/manuscripts are subject to peer review, and commissioning does not automatically guarantee publication.
TIBS 13- March 1988
"rIBS
85
puzzle compiledby Naomi G. Lipsky
Guess the word from the definition provided and write i t over the numbered dashes. Transfer each letter to the corresponding numbered square in the pattern. A black square indicates a word ending, and two indicate the end of a sentence. Any word may be continued on the next line of the pattern. The finished pattern will contain a quotation from the work of a scientist. The first letters of the guessed words will form an acrostic giving the author's name and the title of the work. All entries will be opened on 1 June 1988. The sender of the first correct entry opened will receive a one-year free subscription to TIBS. Send your answers to: TIBS, Elsevier Publications Cambridge, 68 Hills Road, Cambndge CB2 1LA, UK.
16
C 17
H 18
A 19
D
38
L }9
C r'0
P /41
H
~9 AA
~2
L 53
A 6/4
Z 65
K
G
3~ W
37 AA
B8
3 89
K
103 E 10~ F1105 W
106 R
l
130 N
1~3 D 13/4 O 135 P 136 0
153 H
157 A 158 N 159 I
D
13
}0 R 31 J) ~2 B
55
8
J9
F 10
B256
78
~- 79
101 I
G
P 30
HI81
125 ..1 126 C 127 F
149 J 150 W 151 01152 E
173 H 17~ BI175 V i
1
l
II
110 0 ~
-
112 L
180 U 181 O 182 P 18} J
I
A. Achieves funding continuance
B. Rockwaste C. e,g.y-- rex+ b D. Sourceofpudnes and pyrimidines
E. Excskeleton matedal
18 63 47 94 157 187
148695
115 85 32 174 131
16 39 52 68 142 126 163 171
N. 2sidesofa right triangle O. Disconnected from computer (2) P. Uke factodzation into primes Q. Orthorhombic, lead sulpharsanite mineral
29 10 181 108 77 133 155 . . . . . . 78 33 11 103 91 152
R. Smallest mammals S.
F. Lossof speech G. Saltof Dowexor Duolite
Intersection of radius, ulna, and humerus
37 9 104 86 127 165 179 T.
i = V/R (2)
4 14 49 110 43 136 151
40 19 19 135 79 117 182
25 134 74 154 45 50 144 67 106 51 120 30 177
7 15 118 162 99
13 93 178 42 119 124 70
12 98 137 81 56 16834 186 U. Metallic element
H. Vitamin B1
92 130 53 73 158 114 20
3 28 61 169 100 180
96 146 71 17 173 41 122 160
V. An opiate I. Grounds
111 101 1597235 60 W. Fourscore
J. Subject for Pasteur (2) K. Bend waves mound edge L. Unesofequalwind speed
~ ~ ~50 s7 165
s 31 102 125 149 69 183 167
6 121 23 89 154 147 65 44
6-"2 11'~ 2 13"--'2"140 38 17F~ 82
X.
Sitesforfemurs
Y.
Perennial, beloved of Apollo
Z.
Individual's life history
138 97 26 128 58 1!~
24 54 84 48 172 109 141 156
M. Switches to alternate route
95 54 80 21 153 69
AA. Afresh (2)
~ 5"9 8-'7 116 129 184