INFECTION AND IMMUNITYVOLUME 62 * JANUARY 1994 * NUMBER 1

Vincent A. Fischetti, Editor in Chief(1994)

Rockefeller University

Barry I. Eisenstein, Editor (1994)Lilly Research Laboratories

Stanley Falkow, Minireview Editor (1995)Stanford University School ofMedicine

Dexter H. Howard, Editor (1996)University of CaliforniaJohn M. Mansfield, Editor (1998)University of WisconsinRoderick E. McCallum, Editor (1998)Te-xasA&M University HealthScience Center

Jerry R. McGhee, Editor (1994)University ofAlabama

Carol A. Nacy, Editor (1995)EntreMed, Inc.

Alison O'Brien, Editor (1996)Uniformed Services University of theHealth Sciences

Philippe J. Sansonetti, Editor (1997)Institut Pasteur

EDITORIAL BOARDSoman N. Abraham (1994)Julia W. Albright (1995)Glen Armstrong (1995)Sandra K. Armstrong (1996)Joseph T. Barbieri (1995)Alan G. Barbour (1995)Scott Barnum (1995)Joel B. Baseman (1994)Robert E. Baughn (1996)Patrik Bavoil (1996)Kenneth W. Beagley (1996)Blaine L. Beaman (1994)Jorge L. Benach (1995)D. Kay Blanchard (1995)Martin J. Blaser (1995)Arnold S. Bleiweis (1996)Ian Blomfield (1996)W. Chaunce Bogard (1995)Gregory A. Bohach (1996)Patrice Boquet (1996)Patrick Brennan (1994)David E. Briles (1994)Robert R. Brubaker (1996)Drusilla L. Burns (1994)Gerald Byrne (1994)Stephen Calderwood (1994)Harlan Caldwell (1996)Priscilla A. Campbell (1996)Janne G. Cannon (1996)John Chan (1994)Ambrose Cheung (1996)Nicholas P. Cianciotto (1996)Witold Cieplak (1994)John 0. Cisar (1994)Josephine Clark-Curtiss (1996)P. Patrick Cleary (1996)Steven Clegg (1996)Daniel Clemens (1996)John D. Clements (1995)Don B. Clewell (1996)Paul S. Cohen (1996)Stewart Cole (1996)R. John Collier (1994)Frank M. Collins (1995)Guy Cornelis (1996)Rebecca Cox (1996)Jorge H. Crosa (1994)Melanie T. Cushion (1996)Jim E. Cutler (1996)

Barbara H. Iglewski, Chairman,

Charles J. Czuprynski (1995)George S. Deepe, Jr. (1995)Victor DiRita (1996)Judith E. Domer (1995)Michael S. Donnenberg (1996)Gordon Dougan (1994)Lawrence A. Dreyfus (1996)Roman Dziarski (1996)Toby K. Eisenstein (1996)John H. Eldridge (1995)Karen Elkins (1996)Charles 0. Elson (1995)N. Cary Engleberg (1995)Peter B. Ernst (1996)Joseph C. Fantone Im (1996)Joseph J. Ferretti (1995)Brett B. Finlay (1996)Anne H. Fortier (1996)Dara W. Frank (1996)Rolf G. Freter (1996)Jorge Galen (1996)Ronald J. Gibbons (1994)Janet R. Gilsdorf (1996)Mae F. Go (1996)William E. Goldman (1995)Valery Gordon (1996)Emil Gotschlich (1994)Shawn J. Green (1996)Patricia Guerry-Kopecko (1996)Paul A. Gulig (1996)Thomas L. Hale (1996)Jane L. Halpern (1996)Shigeyuki Hamada (1996)Eric J. Hansen (1995)David L. Hasty (1994)Richard Hector (1995)Fred Heffron (1996)Erik Hewlett (1996)James B. Hicks (1994)Harry R. Hill (1996)Susan Hollingshead (1995)Jan Holmgren (1994)Anne Morris Hooke (1995)Ralph R. Isberg (1996)Graham Jackson (1995)Matt Jackson (1995)Thomas R. Jerrells (1996)James B. Kaper (1994)Stefan H. E. Kaufmann (1995)

Publications Board

Paul M. Kaye (1994)Mogens Kilian (1996)Theo N. Kirkland (1995)Hiroshi Kiyono (1995)Dennis J. Kopecko (1995)Malak Kotb (1994)Thomas R. Kozel (1994)J. P. Kraehenbuhl (1996)Arnold Kreger (1995)Howard K. Kuramitsu (1994)David Leiby (1995)Myron Levine (1994)Stephen Lory (1996)David M. Lyerly (1996)Carl F. Marrs (1996)Anthony Maurelli (1996)Bruce McClane (1995)Dennis W. McGee (1996)John Mekalanos (1995)Eleanor S. Metcalf (1995)Suzanne M. Michalek (1995)Virginia L. Miller (1996)Michael L. Misfeldt (1994)Harry Mobley (1995)Robert L. Modlin (1995)Robert N. Moore (1995)Glen J. Morris, Jr. (1996)Steven L. Moseley (1996)Stephen A. Moser (1996)Martha H. Mulks (1995)Robert S. Munford (1996)Robert S. Munson (1995)Juneann W. Murphy (1996)Thalia I. Nicas (1995)Michael V. Norgard (1995)Robert North (1995)Dennis E. Ohman (1995)Ian M. Orme (1996)Paul Orndorff (1996)Michael J. Parmely (1995)Jeffrey Parsonnet (1995)David Pascual (1996)James C. Paton (1996)Shelley M. Payne (1994)Kenneth M. Peterson (1996)Carol Pickett (1996)Gerald B. Pier (1995)Matthew Pollack (1996)Daniel A. Portnoy (1995)

Linda M. Illig, Director, Journals

Richard A. Proctor (1996)Justin D. Radolf (1996)Reuben Ramphal (1994)Jonathan I. Ravdin (1995)Richard F. Rest (1996)Judith C. Rhodes (1995)Donald Robertson (1996)Sara W. Rothman (1996)Craig E. Rubens (1994)Michael W. Russell (1994)Roy R. B. Russell (1995)Isabelle Saint-Girons (1996)Abigail A. Salyers (1996)James Samuel (1995)Stewart Scherer (1994)June R. Scott (1996)Penelope G. Shackelford (1995)Alan Sher (1995)Thomas M. Shinnick (1994)Richard P. Silver (1995)Richard Silverstein (1995)Jerry Simecka (1994)Emil Skamene (1994)Peter G. Sohnle (1996)George Stewart (1996)Susan C. Straley (1995)Barnet M. Sultzer (1994)Catharina Svanborg (1996)Yoshifumi Takeda (1994)Diane W. Taylor (1996)Vernon Tesh (1996)Lucy Tompkins (1996)Trevor J. Trust (1994)Elaine Tuomanen (1996)Rodney K. Tweten (1996)Ivo van de Rjn (1996)Thomas E. Van Dyke (1995)Jan D. A. van Embden (1994)Michael L. Vasil (1996)Peter A. Ward (1994)Alison Weiss (1995)Rodney A. Welch (1996)Dwight M. Williams (1996)Mark E. Wilson (1994)Herbert H. Winkler (1995)Douglas B. Young (1994)Lowell Young (1994)H. Kirk Zeigler (1995)

Jack Kenney, Production Editor

Infection and Immunity, 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 fundamental knowledge concerning: (i) infections caused by pathogenic bacteria, fungi, and parasites;(ii) ecology, epidemiology, and evolution of pathogenic microbes; (iii) mechanisms of pathogenicity and virulence factors such as toxins and microbialsurface structures; (iv) nonspecific factors in host resistance and susceptibility to infection; (v) immunology of microbial infection; and (vi) developmentand evaluation of vaccines against pathogens. Instructions to authors are published in the January issue each year; reprints are available from the editorsand the Journals Division. Infection and Immunity is published monthly, one volume per year. The nonmember print subscription prices are $368 (U.S.)(Canadians add 7% GST) and $431 (other countries) per year; single copies are $43 (Canadians add 7% GST). The member print subscription prices are$51 (U.S.) (Canadians add 7% GST) and $89 (other countries); single copies are $11 (Canadians add 7% GST). For prices of CD-ROM versions, contactthe Subscriptions Unit, ASM. Correspondence relating to subscriptions, defective copies, missing issues, and availability ofback issues should be directedto the Subscriptions Unit, ASM; correspondence relating to reprint orders should be directed to the Reprint Order Unit, ASM; and correspondencerelating to disposition of submitted manuscripts, proofs, and general editorial matters should be directed to the Journals Division, American Society forMicrobiology, 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 the issues;

residents of all other countries must submit claims within 6 months of publication of the issues. Claims for issues missing because of failure to reportan address change or for issues "missing from files" will not be allowed.

Second class postage paid at Washington, DC 20005, and at additional mailing offices.POSTMASTER: Send address changes to Infection and Immunity, ASM, 1325 Massachusetts Ave., N.W., Washington, DC 20005-4171.Made in the United States of America. Printed on acid-free paper.Copyright © 1994, American Society for Microbiology. All Rights Reserved. ISSN 0019-9567 CODEN: INFIBRThe code at the top of the first page of an article in this journal indicates the copyright owner's consent that copies of the article may be made for

personal use or for personal use of specific clients. This consent is given on the condition, however, that the copier pay the stated per-copy fee throughthe Copyright Clearance Center, Inc., 27 Congress St., Salem, MA 01970, for copying beyond that permitted by Sections 107 and 108 of the U.S.Copyright Law. This consent does not extend to other kinds of copying, such as copying for general distribution, for advertising or promotionalpurposes, for creating new collective works, or for resale.

AMERICAN SOCIETY FOR MICROBIOLOGYAND

NATIONAL CENTER FOR INFECTIOUS DISEASES

1994 POSTDOCTORAL RESEARCHASSOCIATES PROGRAM

Up to ten associate positions will be awarded by the American Society for Microbiologyfor full-time research on infectious diseases which cause significant public health problems.Associates will perform research in residence at the National Center for Infectious Diseases(NCID) which is headquartered at the Centers for Disease Control and Prevention (CDC)in Atlanta, GA. In addition to Atlanta, NCID operates laboratories in Ft. Collins, CO,Anchorage, AK, and San Juan, Puerto Rico.

Eligible fields of study include: Bacterial and Mycotic Diseases, Viral and RickettsialInfections, Nosocomial Infections, HIV/AIDS, Vector-borne Infectious Diseases, SexuallyTransmitted Diseases, and Parasitic Diseases.

The program is intended for individuals who have held a doctorate degree (Ph.D., Sc.D.,or M.D.) since, but not earlier than, May 1, 1991. Exceptions may be made for thosewith more experience. The programn is open to both U.S. and foreign citizens. Qualifiedapplicants will receive consideration without regard to race, creed, color, age, sex, ornational origin. Diversity among associates is encouraged. The program provides anannual stipend ranging fromn $28,000 to $33,000 and up to $2,000 for professionaldevelopment.

The application deadline is February 1, 1994. The Postdoctoral Research Program isadministered by the American Society for Microbiology. All inquiries regarding thisprogram should be addressed to: Coordinator, Postdoctoral Research Program, AmericanSociety for Microbiology, 1325 Massachusetts Avenue, N.W., Washington, D.C. 20005;(202) 942-9299.

ASM ODO/NOID|AMERICAN SO1CETY CENTERS FOR DISEASE CONTROL/NATlONAL CENTER FOR INFEC7lOUS DISEASESFOR MICROEIOLOOY AND PREVENTiON

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Author IndexAbdelnour, Arturo, 152Ahrens, Kim P., 91Alley, Evan W., 33Allred, David R., 91Amadio, Sophie, 184Amerongen, Helen M., 15Apter, Felice M., 15Arenberg, Douglas A., 119Arkins, Sean, 1Azad, Abdu F., 316

Bahrami, S., 99Barington, Torben, 9Benach, Jorge L., 303Bernadina, Wilbert, 229Betley, Marsha J., 113Bhardwaj, Nina, 135Blaser, Martin J., 299Boothroyd, John C., 203Borst, Deborah W., 113Bremell, Tomas, 152Bryla, Dolores, 210Bulow, Roland, 203

Cantoni, Lavinia, 29Capodici, Constance, 259Carelli, Maria, 29Cerretti, Douglas P., 325Chen, Anping, 60Chen, Shu, 259Cinque, Rene M., 91Clark-Curtiss, Josephine, 252Cole, Barry C., 135Coleman, James L., 303Collins, William E., 316Colston, M. Joseph, 86Current, William L., 329

Dahlhauser, Paul, 308Danforth, Jean M., 119Dantzer, Robert, 1Darnell, Stephen C., 325Darveau, Richard, 145Deckert-Schluter, M., 221Delgado, Rene, 29del Real, Gustavo, 229Duncan, Margaret, 60Dupont, Michele P., 194

Elsbach, Peter, 259Engel, David, 145Ericsson, M., 178Ernst, Joel D., 127

Fantuzzi, Giamila, 29Fikrig, Erol, 290Flavell, Richard A., 290Friedman, Steven M., 135Fu, Yung-Kang, 1

Gelberg, Howard B., 329

Ghezzi, Pietro, 29Ghiara, Paolo, 29Goldman, Ira F., 316Gower, Candida B., 299Gyhrs, Annette, 9

Haneberg, Bj0rn, 15Harboe, Morten, 252Heilmann, Carsten, 9Hillman, Jeffrey D., 60Hodtsev, Andrew S., 135Hof, H., 221Holiday, Danielle L., 325Holland, Julie, 48Honda, Takeshi, 166Hook, Magnus, 152Horwitz, Marcus A., 280

lida, Tetsuya, 166

Janson, Anneke, 252Jenner, Peter J., 86Jeon, K. W., 65Johnson, Bradley, 145

Kabak, Shara, 135Kampmeier, Jennifer, 203Kantor, Fred S., 290Kaper, James B., 244Katayama, Sei-Ichi, 172Keller, Rhonda G., 215Kelley, Keith W., 1Kendall, Donna, 15Kihlstrom, Erik, 127Killick-Kendrick, Robert, 229Kim, Kami, 203Kim, K. J., 65Klein, Jean-Paul, 184Kolattukudy, Pappachan E.,

79Korth, Marcus J., 41Kozel, Thomas R., 215Kraehenbuhl, Jean-Pierre, 15Krajewska-Pietrasik, Danuta,

152Kristensen, Kim, 9Kuhlenschmidt, Mark S., 329Kunkel, Steven L., 119Kuo, Cho-Chou, 24Kuoppa, K., 178

Lal, Altaf A., 316Lam, Tuan T., 290Lane, Tamara J., 91Lara, J. Cano, 41Lee, Seok-Woo, 60Leichtfried, G., 99Lepoivre, Yves, 184Levitz, Stuart M., 194Li, Yong Ming, 1Louis-Wileman, Valerie, 316

Magnusson, Karl-Eric, 127Majeed, Meytham, 127Marsili, Ilio, 29Matsushita, Osamu, 172Mekalanos, John J., 72Michel, Bryce R., 162Minami, Junzaburo, 172Miwatani, Toshio, 166Mizuguchi, Yasuo, 266Mock, Beverly A., 325Moisset, Anne, 184Montgomery, Ruth R., 290Morrison, David C., 33Moseley, Steve L., 41

Na, Y. E., 65Narayanan, N. P. Shankar, 86Nath, Indira, 86Neutra, Marian R., 15Nguyen, Tuyet-Phuong K.,

290Nisanian, Anahid, 135Noda, Mamoru, 313Norris, Karen A., 236

O'Brien, Alison D., 325O'Connor, Steven P., 319Ogawa, Midori, 266Okabe, Akinobu, 172Ou, Jiongguang, 145

Page, Roy C., 145Parrish, Eloise A., 271Parsons, Tina, 48Patti, Joseph M., 152Perez-Perez, Guillermo I., 299Pfrommer, Gail S. T., 215Pinelli, Elena, 229Polotsky, Vsevolod Y., 210Posnett, David N., 135Potter, Michael, 325Prasad, H. Krishna, 86

Rakita, Robert M., 162Ramesh, Matur V., 79Ramu, Gopal, 86Redl, H., 99Rinke de Wit, Tobias, 252Rizzardini, Milena, 29Robbins, John B., 210Rockey, D. D., 106Rogers, Rene C., 303Rolsma, Mark D., 329Rosa, Patricia A., 303Rosen, Henry, 162Rosquist, J. L., 106Ruitenberg, Joost, 229Russell, Harold, 319Russell, Stephen W., 33Ryden, Cecilia, 152

Sacci, John B., 316

Sakamoto, Haruhiko, 172Sampson, Jacquelyn S., 319Sandstrom, G., 178Sawa, Yoshihiko, 313Schatz, Nada, 184Schlag, G., 99Schlesinger, Larry S., 280Schluter, D., 221Schmidt, D., 221Schneerson, Rachel, 210Scholler, Marie, 184Schreiber, John R., 308Schriefer, Martin E., 316Schrimpf, Jane E., 236Schwendemann, G., 221Scott, Daniel A., 244Shibata, Ken-Ichiro, 313Sidorczyk, Zygmunt, 259Singh, Satish, 86Sirakova, Tatiana, 79Sironi, Marina, 29Sjostedt, A., 178Sjostrom, Karen, 145Smail, Edwin H., 194Smith, Ann, 48Stamm, Lola V., 271Standiford, Theodore J., 119Stendahl, Olle, 127Stinson, Annie R., 319Strieter, Robert M., 119Swanson, Albertina F., 24

Takarada, Yutaka, 166Tarkowski, Andrzej, 152Tarnvik, A., 178Tharpe, Jeane A., 319Thole, Jelle, 252Thulin, Joseph D., 329

van Agterveld, Miranda, 252VanOtteren, Glenn M., 119

Wachsmann, Dominique, 184Wagenaar, Josee, 229Waldor, Matthew K., 72Watanabe, Tsuguo, 313Weiss, Jerrold, 259Whitney, Coralyn, 145Wieles, Brigitte, 252Wiestler, 0. D., 221Williams, Paul, 48Wong, Johann C. Y., 48

Xu, Ming, 166

Yamamoto, Koichiro, 166Yoshida, Shin-Ichi, 266Yu, Y., 99

Zhang, Xiaoke, 33

Copyright ©3 1994. American Society for Microbiology

INFECTION AND IMMUNITY

INSTRUCTIONS TO AUTHORS*

HOW TO SUBMIT MANUSCRIPTS

Submit manuscripts directly to: Journals Division,American Society for Microbiology, 1325 MassachusettsAve., N.W., Washington, DC 20005-4171. Since all sub-missions must be processed through this office, alternaterolutings, such as to an editor, will delay initiation of thereview process. The manuscript must be accompanied bya covering letter stating the following: the journal towhich the manuscript is being submitted, the mostappropriate section of the journal, the complete mailingaddress (including the street), telephone and fax num-bers of the corresponding author, a BITNET or otherelectronic mail address if available, and the former ASMmanuscript number and year if it is a resubmission. It isexpected that the author will include written assurancethat permission to cite personal communications andpreprints has been granted.

Authors may suggest an appropriate editor for newsubmissions. If we are unable to comply with such arequest, the corresponding author will be notified beforethe manuscript is assigned to another editor. To expeditethe review process, authors may recommend at least twoor three reviewers who are not members of their insti-tution(s) and have never been associated with them ortheir laboratory(ies). Please provide the name, address,phone and fax numbers, and area of expertise for each.Note that reviewers so recommended will be used at thediscretion of the editor.

Submit three complete copies of each manuscript,including figures and tables. Type every portion of themanuscript double spaced (a minimum of 6 mm betweenlines), including figure legends, table footnotes, andReferences, and number all pages in sequence, includingthe abstract, figure legends, and tables. Place the last twoitems after the References section. Manuscript pagesmust have margins of at least 1 inch on all four sides andshould have line numbers if possible. It is recommendedthat the following sets of characters be easily distinguish-able in the manuscript: the numeral zero (0) and theletter "oh" (0); the numeral one (1), the letter "el" (1),and the letter "eye" (I); and a multiplication sign ( x )and the letter "ex" (x). If such distinctions cannot bemade, please mark these items at first occurrence for celllines, strain and genetic designations, viruses, etc., on themodified manuscript so that they may be identifiedproperly for the printer by the copy editor. See p. v-vifor detailed instructions about illustrations.

Copies of "in press" and "submitted" manuscriptsthat are important for judgment of the present manu-script should be enclosed to facilitate the review. Threecopies of each such manuscript should be provided.Authors who are unsure of proper English usage

Shading indicates material that has been added or updated.

should have their manuscripts checked by someoneproficient in the English language. Manuscripts may berejected on the basis of poor English or lack of confor-mity to accepted standards of style.

EDITORIAL POLICY

Manuscripts submitted to the journal must representreports of original research. All authors of a manuscriptmust have agreed to its submission and are responsiblefor its content, including appropriate citations and ac-knowledgments, and must also have agreed that thecorresponding author has the authority to act on theirbehalf on all matters pertaining to publication of themanuscript. By submission of a manuscript to the jour-nal, the authors guarantee that the manuscript, or onesubstantially the same, was not published previously, isnot being considered or published elsewhere, and wasnot rejected on scientific grounds by another ASMjournal.

By publishing in the journal, the authors agree thatany plasmids, viruses, and living materials such as mi-crobial strains and cell lines newly described in thearticle are available from a national collection or will bemade available in a timely fashion and at reasonable costto members of the scientific community for noncommer-cial purposes.

Failure to comply with the above-mentioned policiesmay result in a suspension of publishing privileges inASM journals for up to 5 years.

Primary Publication

The American Society for Microbiology accepts thedefinition of primary publication as defined in How toWrite and Publish a Scientific Paper, third edition, byRobert A. Day, to wit: "... (i) the first publication oforiginal research results, (ii) in a form whereby peers ofthe author can repeat the experiments and test theconclusions, and (iii) in a journal or other source docu-ment [emphasis added] readily available within the sci-entific community."A scientific paper published in a conference report,

symposium proceeding, technical bulletin, or any otherretrievable source is unacceptable for submission to anASM journal on grounds of prior publication. A prelim-inary disclosure of research findings published in ab-stract form as an adjunct to a meeting, e.g., part of aprogram, is not considered "prior publication" becauseit does not meet the criteria for a scientific paper.

It is incumbent upon the author to acknowledge anyprior publication of the data contained in a manuscriptsubmitted to an ASM journal even though he or she maynot consider such publication in violation of ASM policy.A copy of the relevant work should accompany thepaper.

INFECTION AND IMMUNITY, Jan. 1994

i

INSTRUCTIONS TO AUTHORS

Permissions

The corresponding author is responsible for obtainingpermissions from both the original publisher and theoriginal author [i.e., the copyright owner(s)] to repro-duce figures, tables, or text (in whole or in part) fromprevious publications. The signed permissions must besubmitted to ASM, and each should be identified as tothe relevant item in the ASM manuscript (e.g., "permis-sions for Fig. 1 in IAI 123-94").

AuthorshipAn author is one who made a substantial contribution

to the "overall design and execution of the experi-ments"; therefore, ASM considers all authors responsi-ble for the entire paper. Individuals who providedassistance, e.g., supplied strains or reagents or critiquedthe paper, need not be listed as authors but may berecognized in the Acknowledgment section.

All authors must agree to the order in which theirnames are listed in the byline. Footnotes regardingattribution of work (e.g., X. Jones and Y. Smith contrib-uted equally to ...) are not permitted. If necessary, suchstatements may be included in the Acknowledgmentsection.

Page ChargesIt is anticipated that page charges, currently $40 per

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If the research was not supported by any of the meansdescribed above, a request to waive the charges may besent to the Journals Division, American Society forMicrobiology, 1325 Massachusetts Ave., N.W., Washing-ton, DC 20005-4171, with the submitted manuscript.This request, which must be separate from the coveringletter, must indicate how the work was supported andshould be accompanied by a copy of the Acknowledg-ment section.

Minireviews and Letters to the Editor (see p. v) arenot subject to page charges.

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sponding author to sign a copyright transfer agreementon behalf of all the authors. This agreement is sent to thecorresponding author when the manuscript is acceptedand scheduled for publication. Unless this agreement isexecuted (without changes and/or addenda), ASM willnot publish the manuscript.

If all authors were employed by the U.S. governmentwhen the work was performed, the corresponding authorshould not sign the copyright transfer agreement butshould, instead, attach to the agreement a statement

attesting that the manuscript was prepared as a part oftheir official duties and, as such, is a work of the U.S.government not subject to copyright.

If some of the authors were employed by the U.S.government when the work was performed but theothers were not, the corresponding author should signthe copyright transfer agreement as it applies to thatportion performed by the non-government employeeauthors.

ScopeIAI is devoted to the advancement and dissemination

of fundamental knowledge concerning: (i) infectionscaused by pathogenic bacteria, fungi, and parasites; (ii)ecology, epidemiology, and evolution of pathogenic mi-crobes; (iii) mechanisms of pathogenicity and virulencefactors such as toxins and microbial surface structures;(iv) nonspecific factors in host resistance and suscepti-bility to infection; (v) immunology of microbial infec-tion; and (vi) development and evaluation of vaccinesagainst pathogens.

IAI will consider papers concerned with the ecology ofpathogenic microbes. Clinical descriptions and papersconcerning the microbiology of hospital environmentsshould be submitted to the Journal of Clinical Microbi-ology. Papers concerned with environmental ecologyshould be submitted to Applied and Environmental Mi-crobiology. Papers dealing with aspects of laboratorydiagnostics or animal models relevant to the diagnosis ofhuman disease should be submitted to Clinical andDiagnostic Laboratory Immunology.

IAI will consider papers concerned with specific andnonspecific immunity to microorganisms, including thefunction of phagocytes, lymphocytes, immunoglobulins,and other factors. Studies of basic immunology andtumor immunology are more appropriate for non- ASMjournals.

IAI will consider papers describing experimental mod-els of infection and the pathological consequences ofinfection. In addition, the journal will consider papersdescribing microbial products that are or may be relatedto pathogenesis. Papers describing microbial products oractivities that are related to diagnosis should be submit-ted to the Journal of Clinical Microbiology. If paperscontain extensive taxonomic material, they should besubmitted to the International Journal of SystematicBacteriology.

IAI will not consider papers concerned with antimi-crobial therapy. These should be submitted to Antimi-crobial Agents and Chemotherapy.

IAI will not consider papers concerned with viralinfections. These should be submitted to the Journal ofVirology.

In most cases, IAI will not consider reports thatemphasize nucleotide sequence data alone (withoutexperimental documentation of the functional and evo-lutionary significance of the sequence).

Papers describing methodology are not encouraged;only under unusual circumstances will they be consid-ered for publication.

INSTRUCTIONS TO AUTHORS

Questions about these guidelines may be directed tothe editor in chief of the journal being considered.

If transfer to another ASM journal is recommendedby an editor, the corresponding author will be contacted.

Note that a manuscript rejected by one ASM journalon scientific grounds or on the basis of its generalsuitability for publication is considered rejected by allother ASM journals.

Nucleotide Sequences

It is expected that GenBank/EMBL accession num-bers for primary nucleotide and/or amino acid sequencedata will be included in the original manuscript or beinserted when the manuscript is modified. (The acces-sion number should be included as a separate paragraphat the end of the Materials and Methods section forfull-length papers or at the end of the text of Notes.)GenBank may be contacted at: GenBank Submis-

sions, National Center for Biotechnology Information,Bldg. 38A, Rm. 8N-803, 8600 Rockville Pike, Bethesda,MD 20894; E-mail (new submissions): gb-sub@ncbi.nlm.nih.gov; E-mail (updates): update@ncbi.nlm.nih.gov. The EMBL Data Library may be contacted at:EMBL Data Library Submissions, Postfach 10.2209,Meyerhofstrasse 1, 69012 Heidelberg, Germany; tele-phone: 011 49 (6221) 387258; fax: 011 49 (6221) 387306;electronic mail (data submissions): datasubs( embl.bit-net.

See p. vii for nucleic acid formatting instructions.

Editorial Style

The editorial style of ASM journals conforms to theCBE Style Manual (5th ed., 1983; Council of BiologyEditors, Inc., 9650 Rockville Pike, Bethesda, Md.),ASMStyle Manual for Journals and Books (American Societyfor Microbiology, 1991), and Robert A. Day's How toWrite and Publish a Scientific Paper (3rd ed., 1988; OryxPress), as interpreted and modified by the editors andthe ASM Journals Division. The editors and the Jour-nals Division reserve the privilege of editing manuscriptsto conform with the stylistic conventions set forth in theaforesaid publications and in these instructions.

Review Process

All manuscripts are reviewed by the editors, membersof the editorial board, or qualified ad hoc reviewers.When a manuscript is submitted to IAI, it is given amanuscript control number and is assigned to one of theeditors. All coauthors are notified of this number andthe editor to whom the manuscript has been assigned. (Itis the responsibility of the corresponding author toinform the coauthors of the manuscript's status through-out the review and publication processes.) The reviewersoperate under strict guidelines set forth in "Guidelinesfor Reviewers" and are expected to complete theirreviews within 3 weeks after receiving the manuscript.The corresponding author is notified, generally within 8weeks after submission, of the editor's decision to ac-cept, reject, or require modification. When a manuscript

is returned to the corresponding author for modification,it should be returned to the editor within 2 months. Ifmore time is required, permission should be obtainedfrom the editor; otherwise it may be considered with-drawn.

Manuscripts that have been rejected, or withdrawnafter being returned for modification, may be resubmit-ted if the major criticisms have been addressed. As withinitial submissions, resubmitted manuscripts should besent to the Journals Division of ASM, not to the editor,and should be accompanied by a cover letter stating thatthe manuscript is a resubmission and describing in somedetail what changes have been made. Resubmittedmanuscripts are normally handled by the original editor.Manuscripts cannot be resubmitted more than onceunless permission has been obtained from the originaleditor or from the editor in chief.

Notification of Acceptance

When an editor has decided that a manuscript isacceptable for publication on the basis of scientificmerit, it is sent to the Journals Division, where it ischecked by the production editor. If the manuscript hasbeen prepared according to the criteria set forth in theseinstructions, it is scheduled for the next available issueand an acceptance letter that indicates the month ofpublication, approximate page proof dates, and sectionis mailed to the corresponding author. The editorial staffof the ASM Journals Division completes the editing ofthe manuscript to bring it into conformity with pre-scribed style and English usage.

Page Proofs

The printer sends page proofs, the copyedited manu-script, and the page charge/reprint order form to thecorresponding author. As soon as the page proofs arecorrected and signed by the person who proofread them(within 48 h), they should be mailed to the ASMJournals Division.The proof stage is not the time to make extensive

corrections, additions, or deletions. Important new in-formation that has become available between accep-tance of the manuscript and receipt of the proofs may beinserted as an Addendum in Proof with the permissionof the editor. If references to unpublished data orpersonal communications are added, it is expected thatwritten assurance granting permission for the citationwill be included. Limit changes to correction of spellingerrors, incorrect data, and grammatical errors and up-dated information for "submitted" and "in press" refer-ences.

Questions about late proofs and problems in theproofs should be directed to the ASM Journals Division,telephone (202) 737-3600.

Reprints

Reprints (in multiples of 100) may be purchased by allcoauthors. An order form that includes a table showing

INSTRUCTIONS TO AUTHORS

the cost of reprints is sent with the proofs to thecorresponding author.

ORGANIZATION AND FORMAT

Regular PapersRegular full-length papers should include the ele-

ments described in this section.

Title, running title, and byline. Each manuscriptshould present the results of an independent, cohesivestudy; thus, numbered series titles are not permitted.Exercise care in composing a title. Avoid the maintitle/subtitle arrangement, complete sentences, and un-

necessary articles. On the title page, include the title,running title (not to exceed 54 characters and spaces),name of each author, address(es) of the institution(s) atwhich the work was performed, each author's affiliation,and a footnote indicating the present address(es) of anyauthor(s) no longer at the institution where the work wasperformed. Place an asterisk after the name of theauthor to whom inquiries regarding the paper should bedirected, and give that author's telephone and faxnumbers.

Correspondent footnote. The complete mailing ad-dress, telephone number, fax number, and electronicmail address of the corresponding author will be pub-lished as a footnote if so desired by the author. Thisinformation should be included in the lower left cornerof the manuscript title page and must be labeled as"Correspondent Footnote." Such footnotes will not beadded at the proof stage.

Abstract. Limit the abstract to 250 words or fewer andconcisely summarize the basic content of the paperwithout presenting extensive experimental details. Avoidabbreviations and do not include diagrams. When it isessential to include a reference, use the Referencescitation but omit the article title. Because the abstractwill be published separately by abstracting services, itmust be complete and understandable without referenceto the text.

Introduction. The introduction should supply suffi-cient background information to allow the reader tounderstand and evaluate the results of the present studywithout referring to previous publications on the topic.The introduction should also provide the rationale forthe present study. Choose references carefully to pro-vide the most salient background rather than an exhaus-tive review of the topic.

Materials and Methods. The Materials and Methodssection should include sufficient technical information toallow the experiments to be repeated. When centrifuga-tion conditions are critical, give enough information toenable another investigator to repeat the procedure:make of centrifuge, model of rotor, temperature, time atmaximum speed, and centrifugal force (x g rather than

revolutions per minute). For commonly used materialsand methods (e.g., media and protein determinations), asimple reference is sufficient. If several alternative meth-ods are commonly used, it is helpful to identify themethod briefly as well as to cite the reference. Forexample, it is preferable to state "cells were broken byultrasonic treatment as previously described (9)" ratherthan "cells were broken as previously described (9)."The reader should be allowed to assess the methodwithout constant reference to previous publications.Describe new methods completely, and give sources ofunusual chemicals, equipment, or microbial strains.When large numbers of microbial strains or mutants areused 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)in a table footnote or figure legend.

Results. In the Results section, include the rationaleor design of the experiments as well as the results;reserve extensive interpretation of the results for theDiscussion section. Present the results as concisely aspossible in one of the following: text, table(s), or fig-ure(s). Avoid extensive use of graphs to present datathat might be more concisely presented in the text ortables. For example, except in unusual cases, double-reciprocal plots used to determine apparent K.,. valuesshould not be presented as graphs; instead, the valuesshould be stated in the text. Similarly, graphs illustratingother graphic methods commonly used to derive kineticor physical constants (e.g., reduced viscosity plots andplots used to determine sedimentation velocity) neednot be shown except in unusual circumstances. Alltabular data must be accompanied by either standarddeviation values or standard errors of the means. Thenumber of replicate determinations (or animals) usedfor making such calculations must also be included. Allstatements concerning the significance of the differencesobserved should be accompanied by probability valuesgiven in parentheses. The statistical procedure usedshould be stated in Materials and Methods. Limit pho-tographs (particularly photomicrographs and electronmicrographs) to those that are absolutely necessary toshow the experimental findings. Number figures andtables in the order in which they are cited in the text, andbe 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.

iv

INSTRUCTIONS TO AUTHORS

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 byfirst author and number consecutively. Abbreviate jour-nal names according to Serial Sources for the BIOSISPreviews Data Base (BioSciences Information Service,1993). Cite each listed reference by number in the text.Follow the styles shown in the examples below.

1. Alderete, J. F., and D. C. Robertson. 1978. Purification andchemical characterization of the heat-stable entero toxinproduced by porcine strains of enterotoxigenic Escherichiacoli. Infect. Immun. 19:1021-1030.

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 Mycobacterilni 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. Miller, J. H. 1972. Experiments in molecular genetics, p.

352-355. Cold Spring Harbor Laboratory, Cold SpringHarbor, N.Y.

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

15. 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.

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

17. Smith, J. C. April 1970. U.S. patent 484,363,770.18. Smyth, D. R. 1972. Ph.D. thesis. University of California,

Los Angeles.19. Yagupsky, P., and M. A. Menegus. 1989. Intraluminal

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

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

Notes

Submit Notes in the same way as full-length papers.They receive the same review, and they are neitherpublished more rapidly than full-length papers nor con-sidered preliminary communications. The Note formatis intended for the presentation of brief observationsthat 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 IAI. 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 the

INSTRUCTIONS TO AUTHORS

Journals 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 correcting-errors 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 Corrections

The Author's Correction section provides a means ofcorrecting 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 thearticle 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 usedthroughout; 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.

Retractions

Retractions are reserved for major errors or breachesof 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 8½ by I1 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: 3/16 inches for a single column and 67/8 inches fora double column (maximum). Include only the significantportion of an illustration. Photos must be of sufficientcontrast to withstand the inevitable loss of contrast anddetail 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 they willappear when published so that no reduction is necessary.If they must be reduced, make sure that all elements,including labeling, can withstand reduction and remainlegible.

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'scopy," 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 ImagesAt 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 produce

Vi

INSTRUCTIONS TO AUTHORS

high-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).

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.

DrawingsSubmit 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 maynot be able to reproduce in the legend.

In figure ordinate and abscissa scales (as well as intable column headings), avoid ambiguous use of num-bers with exponents. Usually, it is preferable to use theInternational System of Units (,u for 10-6, m for 10-3, kfor 103, M for 106, etc.). A complete listing of SI symbolscan be found in the International Union of Pure andApplied Chemistry (IUPAC) "Manual of Symbols andTerminology for Physicochemical Quantities and Units"(Pure Appl. Chem. 21:3-44, 1970). Thus, a representa-

tion of 20,000 cpm on a figure ordinate is to be made bythe number 20, accompanied by the label kcpm.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 labeled as mU (ormilliunits) per ml.

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 conservespace. 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 LegendsLegends should provide enough information so that

the 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.

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 the Abbreviations section ofthese instructions for those that may 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-

.ii

INSTRUCTIONS TO AUTHORS

mat; those with fewer than six pieces of data will beincorporated into the text by the copy editor. A well-constructed table is shown below.

TABLE 1. Trapping of previously perfused piliatedS. typhiniurium by mouse livers

5/S, Recoverv in":Bacteria I Total

Livcr Perfusate recovcry

Control 60.1 ± 11.2 46.2 ± 10.5 106.2 ± 87Previously 39.4 ± 8.4" 66.2 ± 9.5" 105.6 ± 10.3

perfused

Mcan + standard dcviaition of at Icast scven experiments.'P < 0.001 versus control by the White rank order method (21).

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.

NOMENCLATURE

Chemical and Biochemical NomenclatureThe recognized authority for the names of chemical

compounds is Chemical Abstracts (Chemical AbstractService, Ohio State University, Columbus) and its in-dexes. The Merck Index (1lth 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 weight in daltons; molecular

weight is a unitless ratio. Molecular mass is expressed indaltons.

For enzymes, use the recommended (trivial) name

assigned 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.

Amino Acid Sequences

Single-letter designations, rather than three-letterdesignations, should be used for sequences of aminoacids.

DrugsChemical or generic names of drugs should be

used; the use of code numbers or trade names is notpermitted.

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

specific epithet (e.g., Escherichia coli), should be usedfor all 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, and 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 SciencePublishers B.V., Amsterdam, 1984) and Ainsworth andBisby's Dictionary of the Fungi, Including the Lichens, 7thed. (Commonwealth Mycological Institute, Kew, Surrey,England, 1983).

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.

.i.

INSTRUCTIONS TO AUTHORS

A registry of plasmid designations is maintained bythe Plasmid Reference Center, Department of MedicalMicrobiology, Stanford University, Stanford, CA 94304.

Genetic Nomenclature

Bacteria. 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. If your manuscript contains informationincluding genetic nomenclature, please refer to theInstructions to Authors in the January issue of theJournal of Bacteriology.

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 tothe 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.

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). Whenever possible, use the nomenclaturerecommendations of Novick et al. (Bacteriol. Rev. 40:168-189, 1976) for plasmids and plasmid-specified activ-ities, of Low (Bacteriol. Rev. 36:587-607, 1972) forF-prime factors, and of Roberts (Nucleic Acids Res.17:r347-r387, 1989) for restriction enzymes and theirisoschizomers. Recombinant DNA molecules, con-structed in vitro, follow the nomenclature for insertionsin general. DNA inserted into recombinant DNA mole-cules should be described by using the gene symbols andconventions for the organism from which the DNA wasobtained. The Plasmid Reference Center (E. Lederberg,Plasmid Reference Center, Department of Microbiologyand Immunology, 5402, Stanford University School of

Medicine, Stanford, CA 94305-2499) assigns Tn and ISnumbers to avoid conflicting and repetitive use and alsoclears nonconflicting plasmid prefix designations.

ABBREVIATIONS AND CONVENTIONS

Patient IdentificationWhen isolates are derived from patients in clinical

studies, do not identify them by using the patients'initials, even as part of a strain designation. Change theinitials to numerals or use randomly chosen letters. Donot give hospital unit numbers; if a designation isneeded, use only the last two digits of the unit. (Note:Established designations of some viruses and cell lines,although they consist of initials, are acceptable [e.g., JCvirus, BK virus, HeLa cells].)

Verb Tense

ASM strongly recommends that for clarity you use thepast 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.

AbbreviationsGeneral. Abbreviations should be used as an aid to

the reader, rather than as a convenience to the author,and therefore their use should be limited. Abbrevia-tions other than those recommended by the IUPAC-IUB (Biochemical Nomenclature and Related Docui-ments, 1978) should be used only when a case can bemade for necessity, 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 parenthesis thefirst time it is used; e.g., "cultures were grown in Eagle

ix

INSTRUCTIONS TO AUTHORS

minimal essential medium (MEM)." Generally, elimi-nate abbreviations that are not used at least five times inthe 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-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 triphos-phatase, etc.); NAD (nicotinamide adenine dinucleo-tide); NAD+ (nicotinamide adenine dinucleotide, oxi-dized); NADH (nicotinamide adenine dinucleotide, re-duced); NADP (nicotinamide adenine dinucleotidephosphate); NADPH (nicotinamide adenine dinucle-otide phosphate, reduced); NADP+ (nicotinamideadenine dinucleotide phosphate, oxidized); poly(A),poly(dT), etc. (polyadenylic acid, polydeoxythymidylicacid, etc.); oligo(dT), etc. (oligodeoxythymidylic acid,etc.); Pi (orthophosphate); PP1 (pyrophosphate); UV(ultraviolet); PFU (plaque-forming units); CFU (colony-forming units); MIC (minimal inhibitory concentration);MBC (minimal bactericidal concentration); Tris [tris(hy-droxymethyl)aminomethane]; DEAE (diethylamino-ethyl); A260 (absorbance at 260 nm); EDTA (ethyl-enediaminetetraacetic acid); PCR (polymerase chainreaction); and AIDS (acquired immunodeficiency [orimmune deficiency] syndrome). Abbreviations for celllines (e.g., HeLa) also need 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)

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)

no. (number)prepn (preparation)SD (standard deviation)

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 ,prefixes m, p,, n, and p for 10-3, 10-6, 10-9, and10- , respectively. Likewise, use the prefix k for 103.Avoid compound prefixes such as mpL or VL>. Use pLg/mlor ,ug/g in place of the ambiguous ppm. Units oftemperature are presented as follows: 37°C or 324 K.When fractions are used to express units such as

enzymatic activities, it is preferable to use whole units,such as "g" or "min," in the denominator instead offractional or multiple units, such as ,ug or 10 min. Forexample, "pmol/min" would be preferable to "nmol/10min," and "'imol/g" would be preferable to "nmol/4Lg."It is also preferable that an unambiguous form such asthe exponential notation be used; for example, ",umolg- I min-"' 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 SI units for the reporting ofillumination, energy, frequency, pressure, and otherphysical terms. Always report numerical data in theapplicable SI units.

Isotopically Labeled CompoundsFor simple molecules, labeling is indicated in the

chemical formula (e.g., C402, 3H20, H235S04). 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 wordwhich is not a specific chemical name (e.g., 131I-labeledprotein, 14C-amino acids, 3H-ligands, etc.).

For specific chemicals, the symbol for the isotope isplaced in square brackets directly preceding the part ofthe name that describes the labeled entity. Note thatconfiguration symbols and modifiers precede the isoto-pic symbol. The following examples illustrate correctusage:['4C]ureal-[methyl-l4C]methionine[2,3-3H]serine[a-'4C]lysine

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

This journal follows the same conventions for isotopiclabeling as the Journal ofBiological Chemistry, and moredetailed information can be found in the instructions toauthors of that journal (first issue of each year).

x

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