APPLIED AND ENVIRONMENTALMICROBIOLOGYVOLUME 60 JANUARY 1994 * NUMBER 1

Lars G. Ljungdahl, Editor in Chief (1995)University of GeorgiaAthensRobert A. Bender, Editor (1997)University ofMichiganAnn ArborJane Gibson, Editor (1994)Cornell UniversityIthaca, N.Y

Robert J. Maier, Editor (1995)The Johns Hopkins UniversityBaltimore, Md.Kenneth W. Nickerson, Editor (1997)University ofNebraskaLincolnJim C. Spain, Editor (1997)U.S. Air ForceTyndall Air Force Base, Fla.

Barrie F. Taylor, Editor (1994)University ofMiamiMiami, Fla.Richard F. Unz, Editor (1995)Pennsylvania State UniversityUniversity ParkJudy D. Wall, Editor (1997)University ofMissouriColumbia

EDITORIAL BOARDDonald G. Ahearn (1996)Jan R. Andreesen (1994)Daniel Arp (1996)Tamar Barkay (1995)David R. Benson (1995)Claire M. Berg (1994)Deepak Bhatnagar (1996)Linda F. Bisson (1995)Robert Blanchette (1995)Hans Blaschek (1995)David R. Boone (1996)Robert E. Brackett (1995)Gunnar Bratbak (1996)James Brierley (1994)Daniel R. Caldwell (1994)Douglas G. Capone (1996)David A. Caron (1996)Carl E. Cerniglia (1994)Arun Chatterjee (1995)G. Rasul Chaudhry (1995)Tyrrell Conway (1994)Everly Conway de Macano (1994)Donald A. Cooksey (1994)Keith E. Cooksey (1996)Donald L. Crawford (1994)Kurt Dahlberg (1995)Edward F. DeLong (1996)Richard Devereux (1995)Martin Dickman (1996)Harold Drake (1994)David W. Emerich (1995)Stanley L. Erlandsen (1996)Douglas Eveleigh (1994)Samuel R. Farrah (1996)Scott Feighner (1994)Gerald F. Fitzgerald (1994)James C. Fogleman (1996)

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Jane A. Z. Leedle (1994)John F. Leslie (1994)Derek R. Lovley (1995)Peter Luthy (1995)Eugene L. Madsen (1995)Robert E. Marquis (1996)Edward 0. Mason, Jr. (1996)Thomas L. Mason (1996)Ann G. Matthysse (1995)Michael J. McInerney (1995)Richard D. Miller (1994)Charles P. Moran, Jr. (1996)Donald A. Morrison (1996)Mark Morrison (1996)David P. Nagle, Jr. (1994)James P. Nakas (1996)Louise M. Nelson (1995)Walter G. Niehaus, Jr. (1994)J. Martin Odom (1996)Fergal O'Gara (1995)Ronald Olsen (1996)Eric Olson (1994)Tairo Oshima (1996)William J. Page (1995)Samuel A. Palumbo (1994)Leo Parks (1995)Bruce Paster (1994)Christine Paszko-Kolva (1994)Gary Payne (1995)Ian L. Pepper (1994)James J. Pestka (1995)Allen T. Phillips (1995)Wesley 0. Pipes (1995)John I. Pitt (1996)Malcolm Potts (1996)J. T. Pronk (1995)Robert Ramaley (1995)

Donald J. Reasoner (1995)John N. Reeve (1996)Gregor Reid (1996)Donald C. Robertson (1996)Joseph A. Robinson (1996)John P. N. Rosazza (1994)James B. Russell (1995)Michael Jay Sadowsky (1994)Abigail A. Salyers (1995)Peter M. Scott (1996)Barry F. Sherr (1994)C. Jeffrey Smith (1994)James Steele (1995)Michael E. Stiles (1995)Anne 0. Summers (1995)John B. Sutherland (1995)P. G. Thiel (1994)Linda S. Thomashow (1995)John Thompson (1994)Edward Topp (1995)Thomas Tosteson (1996)Peter Van Berkum (1995)Vincent H. Varel (1994)Ross A. Virginia (1994)Edward Voss (1996)Mark Wach (1995)Larry Wackett (1994)Marleen Wekell (1995)Carol L. Wells (1994)Bryan A. White (1996)Michael G. Wolfersberger

(1994)Stephen H. Zinder (1994)David A. Zuberer (1995)Gerben Zylstra (1996)

Barbara H. Iglewski, Chairmnan, Publications BoardJohn N. Bell, Production Editor

Linda M. Illig, Director, JournalsDiane Smith, Assistant Production Editor

Applied and Environmental Microbiology, a publication of the American Society for Microbiology (ASM), 1325 Massachusetts Ave., N.W.,Washington, DC 20005-4171, is devoted to the advancement and dissemination of applied knowledge as well as ecological knowledge, bothapplied and fundamental, concerning microorganisms. Instructions to authors are published in the January issue each year; reprints areavailable from the editors and the Journals Division. Applied and Environmental Microbiology is published monthly, one volume per year.The nonmember print subscription prices are $265 (U.S). (Canadians add 7% GST) and $314 (other countries) per year; single copies are $43(Canadians add 7o GST). The member print subscription prices are $50 (U.S.) (Canadians add 7% GST) and $86 (other countries); singlecopies are $11 (Canadians add 7% GST). For prices of CD-ROM versions, contact the Subscriptions Unit, ASM. Correspondence relating tosubscriptions, defective copies, missing issues, and availability of back issues should be directed to the Subscriptions Unit, ASM;correspondence relating to reprint orders should be directed to the Reprint Order Unit, ASM; and correspondence relating to disposition ofsubmitted manuscripts, proofs, and general editorial matters should be directed to the Journals Division, American Society for Microbiology,1325 Massachusetts Ave., N.W., Washington, DC 20005-4171. Phone: (202) 737-3600.Claims for missing issues from residents of the United States, Canada, and Mexico must be submitted within 3 months after publication of

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Author IndexAkhurst, Raymond J., 120Allard, Marie-Reine, 56Alvarez, Abdiel J., 374Amarger, Noelle, 56Anazawa, Hideharu, 111Aranda, Eduardo, 353Atlas, Ronald M., 368Attwood, Graeme T., 337

Bak, Friedhelm, 291Bak, Rolf P. M., 167Bar-Gilissen, Marie-Jose, 167Barja, J. L., 180Batt, Carl A., 278Becker, J. O., 78Bej, Asim K., 368Bennett, George N., 39Bertheau, Yves, 298Berthier, Yvette, 377Bhat, Manzoor A., 307Bhowmik, Tarun, 333Bittinger, Mark A., 141Blais, Burton W., 348Blanco, Carlos, 341Blaschek, Hans P., 337Boemare, Noel E., 120Bohm, K., 1Bolske, G., 149Bora, Roop Singh, 214Boyce, Martin J., 368Boyer, Joseph N., 174Boynton, Zhuang L., 39Bravo, Alejandra, 353Breen, Alec, 51Brenchley, Jean E., 12Brunke, Maren, 357Buttner, Mark P., 374

Cappenberg, Thomas E., 167Carruthers, F. L., 71Cashore, Alisa, 86Castro, Ieso M., 102Cazemier, Anne E., 271Ceron, Jairo, 353Chen, Huizhong, 64Combe, Marie-Laure, 26Conner, A. J., 71Covarrubias, Luis, 353Cuppers, H. G. A. M., 195,

204

Dalsgaard, Tage, 291Darrasse, Armelle, 298de Bont, Jan A. M., 264, 271Deckwer, W.-D., 357de Jong, Ed, 264, 271de Wit, J. C., 195, 204Diep, Dzung Bao, 160

Dijkhuizen, L., 153Dillard, Helene R., 278Dvorsky, Elizabeth A., 374

Edwards, Aled M., 323Edwards, Elizabeth A., 313,

323Eggeling, Lothar, 126, 133Eikmanns, Bernhard J., 126Engelberg-Kulka, Hanna, 45Ensley, B. D., 285Entian, K.-D., 1

Fernandez, Leonides, 333Field, Jim A., 227, 264, 271Florencio, Lourdinha, 227

Gabel, Christian, 141Gadani, Ferruccio, 19Galama, J. M. D., 149Georgiou, George, 31Gottschalk, Gerhard, 187Grbic-Galic, Dunja, 313, 323Guesdon, Jean-Luc, 377Gutowski-Eckel, Z., 1Gutshall, Kevin, 12

Hammelmann, M., 1Hasumi, Fumihiko, 243Havarstein, Leiv Sigve, 160Heikes, Theresa B., 374Hermes, H. F. M., 153Hill, D. S., 78Hine, Yoshimitsu, 223Holt, Scott M., 337Horiike, Kihachiro, 307Horn, Joanne M., 357Howell, C. R., 78

Ishino, Syuichi, 111Izumi, Yoshikazu, 223

Johansson, K.-E., 149

Kaelin, Pascale, 19Kasmir, Jodie, 12Kelly-Wintenberg, Kimberly,

363Kim, Augustine Y., 337Kissing, J., 149Klein, C., 1Kotoujansky, Alain, 298Kronemeyer, Wolfgang, 126Krumbach, Karin, 133Kubo, Motoki, 243Kurisko, P. R., 285

Lemattre, Monique, 377Lettinga, Gatze, 227Li, Xinliang, 64Ligon, J. M., 78Lin, Sung-Chyr, 31Lina, Laura, 353Ljungdahl, Lars G., 64Loureiro-Dias, Maria C., 102Loveland, Jennifer, 12Lowe, Susan E., 94

Magarifios, B., 180Mahanty, H. K., 71Mahbubani, Meena H., 368Mahoney, Noreen E., 106Maier, Robert J., 141Maki, Kazutoshi, 111Martin, Jean-Pierre, 26Matsuda, Osamu, 248Meijer, E. M., 153Melchers, W. J. G., 149Menn, Fu-Min, 51Mertikas-Pifer, Laura E., 374Michels, Jochen, 187Michotey, Valerie, 341Minton, Mark A., 31Montie, Thomas C., 363Morel, Pascale, 19Morse, A. M., 78Motoyama, Hiroaki, 111Murty, M. G., 214

Nadeau, Lloyd J., 51Nakatsu, Cindy, 86Nakazawa, Teruko, 307Nes, Ingolf F., 160Ng, James, 86Nissen-Meyer, Jon, 160Nozaki, Mitsuhiro, 307

Ogino, Hiroshi, 223Ohshiro, Takashi, 223Okajima, Jyuichi, 243Olsen, Ronald H., 235Ortiz, Anabel, 353Ortiz, Myriam, 353

Pachlatko, J. P., 78Patek, Miroslav, 133Peel, Michelle, 86Podkovyrov, Sergey M., 94Pomeroy, Lawrence R., 328Pons, Jean-Louis, 26Prema, P., 12

Quintero, Rodolfo, 353

Laguerre, Gisele, 56 Rajendran, Narasimmalu, 248

Ramesh, Matur V., 94Reches, Myriam, 45Reinscheid, Dieter J., 126Revoy, Franqoise, 56Rodriguez, Susan B., 106Romalde, J. L., 180Rudolph, Frederick B., 39

Sahm, Hermann, 126, 133Sayler, Gary S., 51Sekar, Vaithilingam, 214Sesboue, Richard, 26Sharma, Mukul M., 31Sheldon, Joan E., 328Sheldon, Wade M., Jr., 328Shenbagarathai, R., 214Shimao, Masayuki, 223Siegers, K., 1Sierka, Raymond A., 344Simidu, Usio, 248Sjogren, Jon C., 344Smigielski, Adam J., 120Sonke, T., 153Spinnler, Henri-Eric, 264Starink, Mathieu, 167Steele, James L., 333Stein, J. I., 78Stetzenbach, Linda D., 374Szilagyi, Ferenc, 86

Tandler, R. F., 153Teshiba, Sadao, 111Thierry, Dominique, 377Tiehm, Andreas, 258Timmis, Kenneth N., 357Toranzo, A. E., 180Toranzos, Gary A., 374Torkewitz, N. R., 78Toro, Arlin, 374Tsuda, Masataka, 307

Urushigawa, Yoshikuni, 248

Vaidyanathan, Chelakara S.,307

van der Logt, J. T. M., 149van Kuppeveld, F. J. M., 149van 't Riet, K., 195, 204

White, Bryan A., 337Wiedmann, Martin, 278Wijnberg, Joannes B. P. A.,

264Wilson, Wendy J., 278Wright, Alice, 235Wyndham, R. Campbell, 86

Zeikus, J. Gregory, 94Zhao, Chengquan, 45Zwietering, M. H., 195, 204

APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Jan. 1994

APPLIED AND ENVIRONMENTAL MICROBIOLOGY

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used in a study, include tables identifying the sourcesand properties of the strains, mutants, bacteriophages,plasmids, etc.A method, strain, etc., used in only one of several

experiments reported in the paper may be described inthe Results section or very briefly (one or two sentences)may be included in a table footnote or figure legend.

Results. In the Results section, include only theresults of the experiments; reserve extensive interpreta-tion of the results for the Discussion section. Present theresults as concisely as possible in one of the following:text, table(s), or figure(s). Avoid extensive use of graphsto present data that might be more concisely presentedin the text or tables. For example, except in unusualcases, double-reciprocal plots used to determine appar-ent Km values should not be presented as graphs;instead, the values should be stated in the text. Similarly,graphs illustrating other methods commonly used toderive kinetic or physical constants (e.g., reduced viscos-ity plots and plots used to determine sedimentationvelocity) need not be shown except in unusual circum-stances. Limit photographs (particularly photomicro-graphs and electron micrographs) to those that areabsolutely necessary to show the experimental findings.Number figures and tables in the order in which they arecited in the text, and be sure to cite all figures and tables.

Discussion. The Discussion should provide an inter-pretation of the results in relation to previously pub-lished work and to the experimental system at hand andshould not contain extensive repetition of the Resultssection or reiteration of the introduction. In short pa-pers, the Results and Discussion sections may be com-bined.

Acknowledgments. Acknowledgments of financial as-sistance and of personal assistance are given in separateparagraphs. The usual format for acknowledgment ofgrant support is as follows: "This work was supported byPublic Health Service grant CA-01234 from the NationalCancer Institute."

Appendixes. Appendixes, which contain supplemen-tary material to aid the reader, are permitted. Titles,authors, and References sections that are distinct fromthose of the primary article are not allowed. If it is notfeasible to list the author(s) of the appendix in the bylineor the Acknowledgment section of the primary article,rewrite the appendix so that it can be considered forpublication as an independent article, either full lengthor Note style. Equations, tables, and figures should belabeled with the letter "A" preceding the numeral todistinguish them from those cited in the main body ofthe text.

References. The References section must include allrelevant sources, and all listed references must be citedin the text. Arrange the citations in alphabetical order,by first author, and number consecutively. Abbreviatejournal names according to Serial Sources for the BIOSIS

iv

INSTRUCTIONS TO AUTHORS

Previews Data Base (BioSciences Information Service,1993). Cite each listed reference by number in the text.

Follow the styles shown in the examples below.

1. Armstrong, J. E., and J. A. Calder. 1978. Inhibitionof light-induced pH increase and 02 evolution of ma-rine microalgae by water-soluble components of crude andrefined oils. Appl. Environ. Microbiol. 35:858-862.

2. Berry, L. J., R. N. Moore, K. J. Goodrum, and R. E. Couch,Jr. 1977. Cellular requirements for enzyme inhibition byendotoxin in mice, p. 321-325. In D. Schlessinger (ed.),Microbiology-1977. American Society for Microbiology,Washington, D.C.

3. Cox, C. S., B. R. Brown, and J. C. Smith. J. Gen. Genet.,in press.*

4. Dhople, A., I. Ortega, and C. Berauer. 1989. Effect ofoxygen on in vitro growth of Mycobacterium leprae, abstr.U-82, p. 168. Abstr. 89th Annu. Meet. Am. Soc. Microbiol.1989.

5. Finegold, S. M., W. E. Shepherd, and E. H. Spaulding.1977. Cumitech 5, Practical anaerobic bacteriology. Coor-dinating ed., W. E. Shepherd. American Society for Mi-crobiology, Washington, D.C.

6. Fitzgerald, G., and D. Shaw. In A. E. Waters (ed.), Clinicalmicrobiology, in press. EFH Publishing Co., Boston.

7. Gill, T. J., III. 1976. Principles of radioimmunoassay, p.169-171. In N. R. Rose and H. Friedman (ed.), Manual ofclinical immunology. American Society for Microbiology,Washington, D.C.

8. Gustlethwaite, F. P. 1985. Letter. Lancet ii:327.9. Jacoby, J., R. Grimm, J. Bostic, V. Dean, and G. Starke.

Submitted for publication.10. Jensen, C., and D. S. Schumacher. Unpublished data.11. Jones, A. (Yale University). 1990. Personal communica-

tion.12. Leadbetter, E. R. 1974. Order II. Cytophagales nomen

novum, p. 99. In R. E. Buchanan and N. E. Gibbons (ed.),Bergey's manual of determinative bacteriology, 8th ed.The Williams & Wilkins Co., Baltimore.

13. Powers, R. D., W. M. Dotson, Jr., and F. G. Hayden. 1982.Program Abstr. 22nd Intersci. Conf. Antimicrob. AgentsChemother., abstr. 448.

14. Sacks, L. E. 1972. Influence of intra- and extracellularcations on the germination of bacterial spores, p. 437-442.In H. 0. Halvorson, R. Hanson, and L. L. Campbell (ed.),Spores V. American Society for Microbiology, Washing-ton, D.C.

15. Sigma Chemical Co. 1989. Sigma manual. Sigma ChemicalCo., St. Louis, Mo.

16. Smith, J. C. April 1970. U.S. patent 484,363,770.17. Smyth, D. R. 1972. Ph.D. thesis. University of California,

Los Angeles.18. Yagupsky, P., and M. A. Menegus. 1989. Intraluminal

colonization as a source of catheter-related infection.Antimicrob. Agents Chemother. 33:2025. (Letter.)

* Note that an "in press" reference to an ASM publica-tion should state the control number (e.g., AEM 576-94)if it is a journal article or the name of the publication ifit is a book.

Notes

Submit Notes in the same way as full-length papers.They receive the same review, they are not publishedmore rapidly than full-length papers, and they are not

considered preliminary communications. The Note for-mat is intended for the presentation of brief observa-tions that do not warrant full-length papers.Each Note must have an abstract of no more than 50

words. Do not use section headings in the body of theNote; report methods, results, and discussion in a singlesection. Paragraph lead-ins are permissible. The textshould be kept to a minimum and if possible should notexceed 1,000 words; the number of figures and tablesshould also be kept to a minimum. Materials andmethods should be described in the text, not in figurelegends or table footnotes. Present acknowledgments asin full-length papers, but do not use a heading. TheReferences section is identical to that of full-lengthpapers.

Minireviews

Minireviews are brief summaries (limit of 4 printedpages) of developments in fast-moving areas. They mustbe based on published articles; they may address anysubject within the scope of AEM. Minireviews may beeither solicited or proffered by authors responding to arecognized need. Irrespective of origin, minireviews aresubject to editorial review. Three double-spaced copiesmust be provided.

Letters to the Editor

Letters to the Editor must include data to support thewriter's argument and are intended only for commentson articles published previously in the journal. They maybe no more than 500 words long. Send letters to theJournals Division. They will be processed and sent to theeditor who handled the article in question. If the editorbelieves that publication is warranted, he will solicit areply from the corresponding author of the article andmake a recommendation to the editor in chief. Finalapproval for publication rests with the editor in chief. Allletters intended for publication must be typed doublespaced.

Errata

The Erratum section provides a means of correctingerrors that occurred during the writing, typing, editing,or printing (e.g., a misspelling, a dropped word or line,mislabeling in a figure, etc.) of a published article. Senderrata directly to the Journals Division.

Author's CorrectionsThe Author's Correction section provides a means of

correcting errors of omission (e.g., author names orcitations) and errors of a scientific nature that do notalter the overall basic results or conclusions of a pub-lished article.For omission of an author's name, the authors of the

article and the author whose name was inadvertentlyomitted must agree to publication of the correction.Letters from both parties must accompany the correc-tion and be sent directly to the Journals Division.

Corrections of a scientific nature (e.g., an incorrectunit of measurement or order of magnitude used

v

INSTRUCTIONS TO AUTHORS

throughout; contamination of one of numerous cultures;misidentification of a mutant or strain, causing errone-ous data for only a portion [noncritical] of the study;etc.) must be sent directly to the editor who handled thearticle. If the editor believes that publication is war-ranted, he will send the correction to the JournalsDivision for publication. Note that the addition of newdata is not permitted.

RetractionsRetractions are reserved for major errors or breaches

of ethics that, for example, may call into question thesource of the data or the validity of the results andconclusions of an article. Send a retraction and anaccompanying explanatory letter signed by all of theauthors directly to the editor in chief of the journal. Theeditor who handled the paper and the chairman of theASM Publications Board will be consulted. If all partiesagree to the publication and content of the retraction, itwill be sent to the Journals Division for publication.

Disclaimers

Statements disclaiming governmental or any othertype of endorsement or approval will be deleted by theJournals Division.

ILLUSTRATIONS AND TABLES

The figure number and authors' names should bewritten on all figures, either in the margin or on the back(marked lightly with a soft pencil). For micrographsespecially, the top should be indicated as well.Do not clasp figures to each other or to the manu-

script with paper clips. Insert small figures in an enve-lope. To avoid damage in transit, do not submit illustra-tions larger than 8/2 by 11 inches.

Illustrations in published articles will not be returnedto authors.

Continuous-Tone and Composite PhotographsWhen submitting continuous-tone photographs (e.g.,

polyacrylamide gels), keep in mind the journal pagewidth: 35/16 inches for a single column and 67/8 inches fora double column (maximum). Include only the signifi-cant portion of an illustration. Photos must be of suffi-cient contrast to withstand the inevitable loss of contrastand detail inherent in the printing process. Submit onephotograph of each continuous-tone figure for each copyof the manuscript; photocopies are not acceptable. Ifpossible, the figures submitted should be the size theywill appear when published so that no reduction isnecessary. If they must be reduced, make sure that allelements, including labeling, can withstand reductionand remain legible.

If a figure is a composite of a continuous-tone photo-graph and a drawing or labeling, the original compositemust be provided for the printer (i.e., not a photographof the composite). This original, labeled "printer's

copy," may be sent with the modified manuscript to theeditor.

Electron and light micrographs must be direct copiesof the original negative. Indicate the magnification witha scale marker on each micrograph.Computer-Generated Images

At this time, the highest-quality and simplest repro-duction of gels (and similar illustrations) continues to bescanning of author-supplied continuous-tone photo-graphs by the printer. However, ASM recognizes theincreasing use of new technology by authors. The fol-lowing information and guidelines will help to ensuregood reproduction of computer-generated images.

Computer-generated images should be produced withAdobe Photoshop or Aldus Freehand software. (Imagesproduced with other types of software may not beacceptable, causing a delay in publication until a substi-tute can be obtained or requiring "editing" by theprinter. Such editing costs will be charged to the author.)

For Aldus, one- and two-column art cannot exceed 20picas (35/16 inches) and 41.5 picas (67/8 inches), respec-tively. The text font should be either Helvetica (mediumor bold) or Times Roman.Adobe users should check the densities of images

on-line. If the image's shadow density reads below 1.25,enter the density as 1.40. If the shadow density readsbetween 1.25 and 1.60, enter the density as 1.65. Anydensity reading above 1.65 should be entered as theactual density reading.

Since the digitized hard copies produced by thesesystems cannot be used by the printer to producehigh-quality images in the printed journal, the computerfiles must be provided by the author. Files (along withprints, which the copy editor will use only for sizing)should be supplied on a floppy disk (Macintosh) with theaccepted manuscript. For large images, 40- or 80-mega-byte Syquest cartridges or magneto-optical cartridgesmay be used. For transfer from UNIX systems, either9-track or 8-mm "tar" archives may be submitted. (Notethat floppies, cartridges, and tapes will not be returnedto the author.) Remember that for this method, all finallettering, labeling, tooling, etc., must be incorporated inthe final supplied material. It cannot be added at a laterdate. Do not include figure numbers on the images incase figure order must be changed during the editingprocess.An "electronic image" telephone hotline has been

established by the ASM printer (The William ByrdPress, Richmond, Va.) to assist authors in producinggels digitally for publication. The numbers for thisservice are (U.S.) 800 888-2973, extension 3361, and(non-U.S.) 804 264-2828, extension 3361. Messages lefton the hotline recorder will be answered within 24 h,during normal business hours.

Since the contents of computer-generated images canbe manipulated for better clarity, the Publications Boardat its May 1992 meeting indicated that a description ofthe software/hardware used should be included in thefigure legend(s).

Vi

INSTRUCTIONS TO AUTHORS

Color Photographs

Color photographs are discouraged. However, if theyare necessary, include an extra copy at the time ofmanuscript submission so that a cost estimate for print-ing may be obtained. The cost of printing color photo-graphs must be borne by the author.

Drawings

Submit graphs, charts, complicated chemical or math-ematical formulas, diagrams, and other drawings asglossy photographs made from finished drawings notrequiring additional artwork or typesetting. Computer-generated graphics produced on high-quality laser print-ers are also usually acceptable. No part of the graph ordrawing should be handwritten. Both axes of graphsmust be labeled. Most graphs will be reduced to one-

column width (35/16 inches), and all elements in thedrawing should be large enough to withstand this reduc-tion. Avoid heavy letters, which tend to close up whenreduced, and unusual symbols, which the printer may

not be able to reproduce in the legend.In figure ordinate and abscissa scales (as well as table

column headings), avoid ambiguous use of numbers withexponents. Usually, it is preferable to use the Interna-tional System of Units (,u for 10-6, m for 10-3, k for 103,M for 106, etc.). A complete listing of SI symbols can befound in the International Union of Pure and AppliedChemistry (IUPAC) "Manual of Symbols and Terminol-ogy for Physicochemical Quantities and Units" (PureAppl. Chem. 21:3-44, 1970). Thus, a representation of20,000 dpm on a figure ordinate is to be made by thenumber 20 accompanied by the label kdpm.When powers of 10 must be used, the journal requires

that the exponent power be associated with the numbershown. In representing 20,000 cells per ml, the numeralon the ordinate would be "2" and the label would be"104 cells per ml" (not "cells per ml x 10-4"). Likewise,an enzyme activity of 0.06 U/ml would be shown as 6,accompanied by the label 10 -2 U/ml. The preferreddesignation would be 60 mU/ml (milliunits per millili-ter).

Presentation of Nucleic Acid SequencesNucleic acid sequences of limited length which are the

primary subject of a study may be presented freestyle inthe most effective format. Longer nucleic acid sequencesmust be presented in the following format to conserve

space. Submit the sequence as camera-ready copy ofdimensions 8/2 by 11 inches (or slightly less) in standard(portrait) orientation. Print the sequence in lines of 100bases, each in a nonproportional (monospace) fontwhich is easily legible when published at 100 bases/6inches. Uppercase and lowercase letters may be used todesignate the exon/intron structure, transcribed regions,etc., if the lowercase letters remain legible at 100 bases/6inches. Number the sequence line by line; place numer-

als, representing the first base of each line, to the left ofthe lines. Minimize spacing between lines of sequence,

leaving room only for annotation of the sequence. An-notation may include boldface, underlining, brackets,boxes, etc. Encoded amino acid sequences may bepresented, if necessary, immediately above the firstnucleotide of each codon, by using the single-letteramino acid symbols. Comparisons of multiple nucleicacid sequences should conform as nearly as possible tothe same format.

Figure Legends

Legends should provide enough information so thatthe figure is understandable without frequent referenceto the text. However, detailed experimental methodsmust be described in the Materials and Methods section,not in a figure legend. A method that is unique to one ofseveral experiments may be reported in a legend only ifthe discussion is very brief (one or two sentences).Define all symbols and abbreviations used in the figurethat have not been defined elsewhere.

TABLE 1. Distribution of protein and ATPase in fractions ofdialyzed membranes'

ATPaseMembranes Fraction U/mg of

protein

Control Depleted membrane 0.036 2.3Concentrated supernatant 0.134 4.82

El treated Depleted membrane 0.034 1.98Concentrated supernatant 0.11 4.6

aSpecific activities of ATPase of nondepleted membranes from control andtreated bacteria were 0.21 and 0.20, respectively.

Tables

Type each table on a separate page. Arrange the dataso that columns of like material read down, not across.The headings should be sufficiently clear so that themeaning of the data will be understandable withoutreference to the text. See "Abbreviations" in theseinstructions for those that should be used in tables.Explanatory footnotes are acceptable, but more exten-sive table "legends" are not. Footnotes should notinclude detailed descriptions of the experiment. Tablesmust include enough information to warrant table for-mat; those with fewer than six pieces of data will beincorporated into the text by the copy editor. A well-constructed table is shown above.

Tables that can be photographically reproduced forpublication without further typesetting or artwork arereferred to as "camera ready." They should not be handlettered and must be carefully prepared to conform withthe style of the journal. The advantage of submittingcamera-ready copy is that the material will appearexactly as envisioned by the author, and no secondproofreading is necessary. This is particularly advanta-geous when there are long, complicated tables and whenthe division of material and spacing are important.

.ii

INSTRUCTIONS TO AUTHORS

NOMENCLATURE

Chemical and Biochemical NomenclatureThe recognized authority for the names of chemical

compounds is Chemical Abstracts (Chemical AbstractsService, Ohio State University, Columbus) and its in-dexes. The Merck Index (llth ed., 1989; Merck & Co.,Inc., Rahway, N.J.) is also an excellent source. Forbiochemical terminology, including abbreviations andsymbols, consult Biochemical Nomenclature and RelatedDocuments (1978; reprinted for The Biochemical Soci-ety, London) and the instructions to authors of theJournal of Biological Chemistry and the Archives ofBiochemistry and Biophysics (first issues of each year).Do not express molecular weights in daltons; molec-

ular weight is a unitless ratio. Molecular mass is ex-pressed in daltons.

For enzymes, use the recommended (trivial) nameassigned by the Nomenclature Committee of the Inter-national Union of Biochemistry as described in EnzymeNomenclature (Academic Press, Inc., 1992). If a nonrec-ommended name is used, place the proper (trivial) namein parentheses at first use in the abstract and text. Usethe EC number when one has been assigned, and expressenzyme activity either in katals (preferred) or in theolder system of micromoles per minute.

Nomenclature of MicroorganismsBinary names, consisting of a generic name and a

specific epithet (e.g., Escherichia coli), must be used forall microorganisms. Names of categories above thegenus level may be used alone, but specific and subspe-cific epithets may not. A specific epithet must be pre-ceded by a generic name the first time it is used in apaper. Thereafter, the generic name should be abbrevi-ated to the initial capital letter (e.g., E. coli), providedthere can be no confusion with other genera used in thepaper. Names of all taxa (phyla, classes, orders, families,genera, species, subspecies) are printed in italics andshould be underlined (or italicized) in the manuscript;strain designations and numbers are not.The spelling of names should follow the Approved

Lists of Bacterial Names (amended edition) (V. B. D.Skerman, V. McGowan, and P. H. A. Sneath, ed.) andthe Index of the Bacterial and Yeast NomenclaturalChanges Published in the International Journal of System-atic Bacteriology since the 1980 Approved Lists of Bacte-rial Names (1 January 1980 to 1 January 1989) (W. E. C.Moore and L. V. H. Moore, ed.), both published by theAmerican Society for Microbiology in 1989, and thevalidation lists and articles published in the InternationalJournal of Systematic Bacteriology since 1 January 1989.If there is reason to use a name that does not havestanding in nomenclature, the name should be enclosedin quotation marks and an appropriate statement con-cerning the nomenclatural status of the name should bemade in the text (for an example, see Int. J. Syst.Bacteriol. 30:547-556, 1980).

It is recommended that a strain be deposited in arecognized culture collection when that strain is neces-

sary for the description of a new taxon (see Bacteriolog-ical Code, 1990 Revision, American Society for Micro-biology, 1992).

Since the classification of fungi is not complete, it isthe responsibility of the author to determine the ac-cepted binomial for a given organism. Some sources forthese names include The Yeasts: a Taxonomic Study, 3rded. (N. J. W. Kreger-van Rij, ed., Elsevier Science Pub-lishers B.V., Amsterdam, 1984) and Ainsworth and Bis-by's Dictionary ofthe Fungi, Including the Lichens, 7th ed.(Commonwealth Mycological Institute, Kew, Surrey,England, 1983).Names used for viruses should be those approved by

the International Committee on Taxonomy of Viruses(ICTV) and published in the 4th Report of the ICTV,Classification and Nomenclature of Viruses (Intervirol-ogy 17:23-199, 1982), with the modifications containedin the 5th Report of the ICTV (Arch. Virol., Suppl. 2,1991). If desired, synonyms may be added parentheti-cally when the name is first mentioned. Approved ge-neric (or group) and family names may also be used.

Microorganisms, viruses, and plasmids should begiven designations consisting of letters and serial num-bers. It is generally advisable to include a worker'sinitials or a descriptive symbol of locale, laboratory, etc.,in the designation. Each new strain, mutant, isolate, orderivative should be given a new (serial) designation.This designation should be distinct from those of thegenotype and phenotype, and genotypic and phenotypicsymbols should not be included.

Genetic NomenclatureBacteria. The genetic properties of bacteria are de-

scribed in terms of phenotypes and genotypes. Thephenotype describes the observable properties of anorganism. The genotype refers to the genetic constitu-tion of an organism, usually in reference to somestandard wild type. Use the recommendations of Deme-rec et al. (Genetics 54:61-76, 1966) as a guide to the useof these terms.

(i) Phenotypic designations must be used when mu-tant loci have not been identified or mapped. They canalso be used to identify the protein product of a gene,e.g., the OmpA protein. Phenotypic designations gener-ally consist of three-letter symbols; these are not itali-cized, and the first letter of the symbol is capitalized. Itis preferable to use roman or arabic numerals (instead ofletters) to identify a series of related phenotypes. Thus,a series of nucleic acid polymerase mutants might bedesignated Poll, Pol2, Pol3, etc. Wild-type characteris-tics can be designated with a superscript plus (Pol+) and,when necessary for clarity, negative superscripts (Pol-)can be used to designate mutant characteristics. Lower-case superscript letters may be used to further delineatephenotypes (e.g., Strs for streptomycin sensitivity). Phe-notypic designations should be defined.

(ii) Genotypic designations are similarly indicated bythree-letter locus symbols. In contrast to phenotypicdesignations, these are lowercase italic (e.g., ara his rps).If several loci govern related functions, these are distin-

. .i.

INSTRUCTIONS TO AUTHORS

guished by italicized capital letters following the locussymbol (e.g., araA araB araC). Promoter, terminator,and operator sites should be indicated as described byBachmann and Low (Microbiol. Rev. 44:1-56, 1980),e.g., lacZp, lacAt, and lacZo.

(iii) Wild-type alleles are indicated with a superscriptplus (ara+ his'). A superscript minus is not used toindicate a mutant locus; thus, one refers to an aramutant rather than an ara- strain.

(iv) Mutation sites are designated by placing serialisolation numbers (allele numbers) after the locus sym-bol (e.g., araAl araA2). If it is not known in which ofseveral related loci the mutation has occurred, a hyphenis used instead of the capital letter (e.g., ara-23). It isessential in papers reporting the isolation of new mu-tants that allele numbers be given to the mutations. ForEscherichia coli, there is a registry of such numbers: E.coli Genetic Stock Center, Department of Biology, YaleUniversity, New Haven, CT 06511-5188. For Salmonella,the registry is: Salmonella Genetic Stock Center, Depart-ment of Biology, University of Calgary, Calgary, Alberta,T2N 1N4 Canada. For Bacillus, the registry is: BacillusGenetic Stock Center, Ohio State University, Columbus.A registry of allele numbers and insertion elements(omega [fQ] numbers) for chromosomal mutations andchromosomal insertions of transposons and other inser-tion elements has been established in conjunction withthe ISP collection of Staphylococcus aureus at Iowa StateUniversity. Blocks of allele numbers and fl numbers areassigned to laboratories on request. Requests for blocksof numbers and additional information can be obtainedfrom Peter A. Pattee, Department of Microbiology,Iowa State University, Ames, IA 50011. A registry ofplasmid designations is maintained by the Plasmid Ref-erence Center, Department of Medical Microbiology,Stanford University, Stanford, CA 94305.

(v) The use of superscripts with genotypes (other than+ to indicate wild-type alleles) should be avoided.Designations indicating amber mutations (Am), temper-ature-sensitive mutations (Ts), constitutive mutations(Con), cold-sensitive mutations (Cs), production of ahybrid protein (Hyb), and other important phenotypicproperties should follow the allele number [e.g.,araA230(Am) hisD2J(Ts)]. All other such designationsof phenotype must be defined at the first occurrence. Ifsuperscripts must be used, they must be approved by theeditor and they must be defined at the first occurrence.

Subscripts may be used in two situations. Subscriptsmay be used to distinguish between genes (having thesame name) from different organisms or strains, e.g.,hisE coli or hisKl12 for the his genes of E. coli or strainK-12 in another species or strain, respectively. Anabbreviation may also be used if it is explained. Simi-larly, a subscript is also used to distinguish betweengenetic elements that have the same name. For example,the promoters of the gln operon can be designatedglnAp, and glnAp2. This form departs slightly from thatrecommended by Bachmann and Low (e.g., desClp).

(vi) Deletions are indicated by the symbol A placedbefore the deleted gene or region, e.g., AtrpA432,

A(aroP-aceE)419, or Ahis(dhuA hisJ hisQ)1256. Simi-larly, other symbols can be used (with appropriatedefinition). Thus, a fusion of the ara and lac op-erons can be shown as 'I(ara-lac)95. Similarly, 'I(araB'-lacZ+)96 indicates that the fusion results in a truncatedaraB gene fused to an intact lacZ, and ID(malE-lacZ)97(Hyb) shows that a hybrid protein is synthesized.An inversion is shown as IN(rrnD- rrnE)J. An insertionof an E. coli his gene into plasmid pSC101 at zerokilobases (0 kb) is shown as pSC101 fQ(Okb::K-12hisB)4.An alternative designation of an insertion can be used insimple cases, e.g., galT236::TnS. The number 236 refersto the locus of the insertion, and if the strain carries anadditional gal mutation, it is listed separately. Additionalexamples, which utilize a slightly different format, can befound in the papers by Campbell et al. and Novick et al.cited below. It is important in reporting the constructionof strains in which a mobile element was inserted andsubsequently deleted that this latter fact be noted in thestrain table. This can be done by listing the genotype ofthe strain used as an intermediate, in a table footnote, orby a direct or parenthetical remark in the genotype, e.g.,(F-), AMu cts, mal::AMu cts::lac. In setting parenthet-ical remarks within the genotype or dividing the geno-type into constituent elements, parentheses and squarebrackets are used without special meaning; squarebrackets are used outside parentheses. To indicate thepresence of an episome, parentheses (or brackets) areused (X, F+). Reference to an integrated episome isindicated as described above for inserted elements, andan exogenote is shown as, for example, W3110/F'8(gal+).Any deviations from standard genetic nomenclature

should be explained in Materials and Methods or in atable of strains. For information about the symbols incurrent use, consult Bachmann (B. J. Bachmann, p.807-876, in J. L. Ingraham, K. B. Low, B. Magasanik, M.Schaechter, and H. E. Umbarger, ed., Escherichia coliand Salmonella typhimurium: Cellular and MolecularBiology, 1987, American Society for Microbiology,Washington, D.C.) for E. coli K-12, Sanderson and Roth(Microbiol. Rev. 52:485-532, 1988) for Salmonella typhi-murium, Holloway et al. (Microbiol. Rev. 43:73-102,1979) for Pseudomonas, Piggot and Hoch (Microbiol.Rev. 49:158-179, 1985) for Bacillus subtilis, Perkins et al.(Microbiol. Rev. 46:426-570, 1982) for Neurosporacrassa, and Mortimer and Schild (Microbiol. Rev. 49:181-213, 1985) for Saccharomyces cerevisiae. For yeasts,Chlamydomonas, and several fungal species, symbolssuch as those given in the Handbook ofMicrobiology (A.I. Laskin and H. A. Lechevalier, ed., CRC Press, Inc.,1974) should be used.

Conventions for naming genes. It is recommendedthat new genes whose function is yet to be established benamed by one of the following methods. (i) Whenapplicable, the new gene may be given the same name asa homologous gene already identified in another organ-ism. (ii) The gene may be given a provisional namebased on its map location in the style yaaA, analogous to

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INSTRUCTIONS TO AUTHORS

the style used for recording transposon insertions (zef) asdiscussed below. (iii) A provisional name may be givenin the style described by Demerec et al. (e.g., usg, forgene upstream of folC).

"Mutant" vs. "mutation." Keep in mind the distinc-tion between a mutation (an alteration of the primarysequence of the genetic material) and a mutant (a straincarrying one or more mutations). One may speak aboutthe mapping of a mutation, but one cannot map amutant. Likewise, a mutant has no genetic locus, only aphenotype.

Strain designations. Do not use a genotype as a name(e.g., "subsequent use of leuC6 for transduction"). If astrain designation has not been chosen, select an appro-priate word combination (e.g., "another strain contain-ing the leuC6 mutation").

Viruses. The genetic nomenclature for viruses differsfrom that for bacteria. In most instances, viruses have nophenotype, since they have no metabolism outside hostcells. Therefore, distinctions between phenotype andgenotype cannot be made. Superscripts are used toindicate hybrid genomes. Genetic symbols may be one,two, or three letters. For example, a mutant strain of Amight be designated as AAamll int2 redll4 c1857; thisstrain carries mutations in genes cI, int, and red and anamber-suppressible (am) mutation in gene A. A straindesignated X att434 imm21 would represent a hybrid ofphage X which carries the immunity region (imm) ofphage 21 and the attachment (att) region of phage 434.Host DNA insertions into viruses should be delineatedby square brackets, and the genetic symbols and desig-nations for such inserted DNA should conform to thoseused for the host genome. Genetic symbols for phage Xcan be found in Szybalski and Szybalski (Gene 7:217-270, 1979) and in Echols and Murialdo (Microbiol. Rev.42:577-591, 1978).

Transposable elements, plasmids, and restriction en-zymes. Nomenclature of transposable elements (inser-tion sequences, transposons, phage Mu, etc.) shouldfollow the recommendations of Campbell et al. (Gene5:197-206, 1979), with the modifications given in sectionvi. The system of designating transposon insertions atsites where there are no known loci, e.g., zef-123::Tn5,has been described by Chumley et al. (Genetics 91:639-655, 1979). The nomenclature recommendations of Nov-ick et al. (Bacteriol. Rev. 40:168-189, 1976) for plasmidsand plasmid-specified activities, of Low (Bacteriol. Rev.36:587-607, 1972) for F-prime factors, and of Roberts(Nucleic Acids Res. 17:r347-r387, 1989) for restrictionenzymes and their isoschizomers should be used whenpossible. Recombinant DNA molecules constructed invitro follow the nomenclature for insertions in general.DNA inserted into recombinant DNA molecules shouldbe described by using the gene symbols and conventionsfor the organism from which the DNA was obtained.The Plasmid Reference Center (E. Lederberg, Plasmid

Reference Center, Department of Microbiology andImmunology, 5402, Stanford University School of Med-icine, Stanford, CA 94305-2499) assigns Tn and ISnumbers to avoid conflicting and repetitive use and alsoclears nonconflicting plasmid prefix designations.

ABBREVIATIONS AND CONVENTIONS

Verb TenseASM strongly recommends that for clarity you use the

past tense to narrate particular events in the past,including the procedures, observations, and data of thestudy that you are reporting. Use the present tense foryour own general conclusions, the conclusions of previ-ous researchers, and generally accepted facts. Thus,most of the abstract, Materials and Methods, and Re-sults sections will be in the past tense, and most of theintroduction and some of the Discussion will be in thepresent tense.Be aware that it may be necessary to vary the tense in

a single sentence. For example, it is correct to say"White (30) demonstrated that XYZ cells grow at pH6.8," "Figure 2 shows that ABC cells failed to grow atroom temperature," and "Air was removed from thechamber and the mice died, which proves that micerequire air." In reporting statistics and calculations, it iscorrect to say "The values for the ABC cells are statis-tically significant, indicating that the drug inhibited...."For an in-depth discussion of tense in scientific writ-

ing, see p. 158-160 in How to Write and Publish aScientific Paper, 3rd ed.

Abbreviations

General. Abbreviations should be used as an aid to thereader rather than as a convenience to the author, andtherefore their use should be limited. Abbreviationsother than those recommended by the IUPAC- IUB(Biochemical Nomenclature and Related Documents,1978) should be used only when a case can be made fornecessity, such as in tables and figures.

It is often possible to use pronouns or to paraphrase along word after its first use (e.g., "the drug," "thesubstrate"). Standard chemical symbols and trivialnames or their symbols (folate, Ala, Leu, etc.) may beused for terms that appear in full in the neighboring text.

It is strongly recommended that all abbreviationsexcept those listed below be introduced in the firstparagraph in Materials and Methods. Alternatively, de-fine each abbreviation and introduce it in parenthesesthe first time it is used; e.g., "cultures were grown inEagle minimal essential medium (MEM)." Generally,eliminate abbreviations that are not used at least fivetimes in the text (including tables and figure legends).

Not requiring introduction. In addition to abbrevia-tions for Systeme International d'Unites (SI) units ofmeasurement, other common units (e.g., bp, kb, andDa), and chemical symbols for the elements, the follow-ing should be used without definition in the title, ab-

x

INSTRUCTIONS TO AUTHORS

stract, text, figure legends, and tables: DNA (deoxyribo-nucleic acid); cDNA (complementary DNA); RNA(ribonucleic acid); cRNA (complementary RNA);RNase (ribonuclease); DNase (deoxyribonuclease);rRNA (ribosomal RNA); mRNA (messenger RNA);tRNA (transfer RNA); AMP, ADP, ATP, dAMP,ddATP, GTP, etc. (for the respective 5' phosphates ofadenosine and other nucleosides) (add 2'-, 3'-, or 5'-when needed for contrast); ATPase, dGTPase, etc.(adenosine triphosphatase, deoxyguanosine triphospha-tase, etc.); NAD (nicotinamide adenine dinucleotide);NAD+ (nicotinamide adenine dinucleotide, oxidized);NADH (nicotinamide adenine dinucleotide, reduced);NADP (nicotinamide adenine dinucleotide phosphate);NADPH (nicotinamide adenine dinucleotide phosphate,reduced); NADP+ (nicotinamide adenine dinucleotidephosphate, oxidized); poly(A), poly(dT), etc. (polyade-nylic acid, polydeoxythymidylic acid, etc.); oligo(dT),etc. (oligodeoxythymidylic acid, etc.); Pi (orthophos-phate); PP1 (pyrophosphate); UV (ultraviolet); PFU(plaque-forming units); CFU (colony-forming units);MIC (minimal inhibitory concentration); MBC (minimalbactericidal concentration); Tris [tris(hydroxymethyl)aminomethane];DEAE (diethylaminoethyl);A260 (absor-bance at 260 nm); EDTA (ethylenediaminetetraaceticacid); PCR (polymerase chain reaction); and AIDS(acquired immunodeficiency [or immune deficiency]syndrome). Abbreviations for cell lines (e.g., HeLa) alsoneed not be defined.The following abbreviations should be used without

definition in tables:

amt (amount)approx (approximately)avg (average)concn (concentration)diam (diameter)expt (experiment)exptl (experimental)ht (height)mo (month)mol wt (molecular weight)no. (number)prepn (preparation)SD (standard deviation)

SE (standard error)SEM (standard error of themean)

sp act (specific activity)sp gr (specific gravity)temp (temperature)tr (trace)vol (volume)vs (versus)wk (week)wt (weight)yr (year)

Reporting Numerical Data

Standard metric units are used for reporting length,weight, and volume. For these units and for molarity, usethe ?refixes m, ,u, n, and p for 10-3, 10-6, 10-, and10- , respectively. Likewise, use the prefix k for 103.Avoid compound prefixes such as m,.i or jLL. Parts permillion (ppm) may be used when that is the commonmeasure for the science in that field. Units of tempera-ture are presented as follows: 37°C or 324 K.When fractions are used to express such units as

enzymatic activities, it is preferable to use whole units,such as g or min, in the denominator instead of frac-tional or multiple units, such as ,ug or 10 min. Forexample, "pmol/min" would be preferable to "nmol/10

min," and "jimol/g" would be preferable to "nmol/pg."It is also preferable that an unambiguous form, such asexponential notation, be used; for example, ",umol g-1min-m" is preferable to ",umol/g/min."

See the CBE Style Manual, 5th ed., for more detailedinformation about reporting numbers. Also contained inthis source is information on the appropriate SI units forreporting illumination, energy, frequency, pressure, andother physical terms. Always report numerical data inthe applicable SI units.

Statistics

If biological variation within a treatment (coefficientof variation, the standard deviation divided by the mean)is small (less than 10%) and the difference amongtreatment means is large (greater than 3 standard devi-ations), it is not necessary to report statistics. If the datado not meet these criteria, however, the authors mustinclude an appropriate statistical analysis (e.g., Student'st test, analysis of variance, Tukey's test, etc.). Statisticsshould represent the variation among biological units(e.g., replicate incubations) and not just the variationdue to method of analysis.

EquationsIn mathematical equations, indicate the order of

operations clearly by enclosing operations in parenthe-ses, brackets, and braces, in that order: (a + b) x c or a+ (b x c), 100 x {[(a/b) x c] + d} or 100 x {a/[(b x c)+ d]}. Italicize (by underlining) variables and constants(but not numerals), and use roman type for designations:Eo, Eh, Mr Kin Ks, a + 2b = 1.2 mM, Ca2+Vmax -exp(l.5x + y), BOD = 2.7x2.

Isotopically Labeled CompoundsFor simple molecules, isotopic labeling is indicated in

the chemical formula (e.g., 14C02, 3H2, H35SO4). Brack-ets are not used when the isotopic symbol is attached tothe name of a compound that in its natural state doesnot contain the element (e.g., 32S-ATP) or to a word thatis not a specific chemical name (e.g., 1311-labeled protein,4C-amino acids, 3H-ligands, etc.).For specific chemicals, the symbol for the isotope

introduced is placed in brackets directly preceding thepart of the name that describes the labeled entity. Notethat configuration symbols and modifiers precede theisotopic symbol. The following examples illustrate cor-rect usage.

['4C]ureal-[methyl-14C]methionine[2,3-3H]serine[x-'4C]lysine[y-32P]ATP

UDP-[U-'4C]glucoseE. coli [32P]DNAfructose 1,6-[1-32P]bisphos-

phate

AEM follows the same conventions for isotopic labelingas the Journal ofBiological Chemistry, and more detailedinformation can be found in the instructions to authorsof that journal (first issue of each year).

Xi