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Stephen ArnoffPatrick J. Piggot, PhD


Professor, Microbiology and Immunology

Telephone:  215-707-7927

Fax:  215-707-7788

Email: patrick.piggot@temple.edu


Department of Microbiology and Immunology


Educational Background:


University of London, United Kingdom, PhD


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Research Interests:


Two fundamental problems of biology are how cell type-specific gene expression is established and maintained, and how gene expression is coordinated with morphological change. They are central to an understanding of cell differentiation. They are approached through a study of the formation of spores by Bacillus subtilis. Spore formation by B. subtilis is a primitive system of cell differentiation that has become a paradigm for the study of cell differentiation in prokaryotes. Differential gene expression between the different cell types involved is directed by the activation of distinct RNA polymerase sigma factors. Three different lines of research are being pursued:

  1. Studying how modulating cell-cell signaling changes the subsequent developmental pathway. This is being pursued through the analysis of strains that form two spores within on mother cell;
  2. Analyzing how completion of engulfment of the prespore by the mother cell results in activation of sigma G in the prespore;
  3. Analyzing the controls that ordinarily keep sigma E activity confined to the mother cell..

The second major research interest is an analysis of the stationary phase behavior of Streptococcus mutans in batch culture and in biofilms. This project is in collaboration with Dr. Buttaro. Critical questions include how do bacteria survive in stationary phase? How does mucin extend survival? How well do bacteria respond to restoration of nutrients and to acid shock? How able are they to seed biofilm formation elsewhere? Fluorescent protein probes have been developed in order to distinguish different cell populations within biofilms and to study how they respond to environmental change.


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Recent Medically Related Publications, Obtained from PubMed (Click on PubMed ID to view abstract)

24261873. Mothey D, Buttaro BA, Piggot PJ, Mucin can enhance growth, biofilm formation, and survival of Streptococcus mutans. FEMS Microbiol Lett 350:2(161-7)2014 Jan

22984259. Regan G, Itaya M, Piggot PJ, Coupling of sG activation to completion of engulfment during sporulation of Bacillus subtilis survives large perturbations to DNA translocation and replication. J Bacteriol 194:22(6264-71)2012 Nov

21478340. Xenopoulos P, Piggot PJ, Regulation of growth of the mother cell and chromosome replication during sporulation of Bacillus subtilis. J Bacteriol 193:12(3117-26)2011 Jun

20802044. Chary VK, Xenopoulos P, Eldar A, Piggot PJ, Loss of compartmentalization of s(E) activity need not prevent formation of spores by Bacillus subtilis. J Bacteriol 192:21(5616-24)2010 Nov

20581205. Busuioc M, Buttaro BA, Piggot PJ, The pdh operon is expressed in a subpopulation of stationary-phase bacteria and is important for survival of sugar-starved Streptococcus mutans. J Bacteriol 192:17(4395-402)2010 Sep

19801415. Busuioc M, Mackiewicz K, Buttaro BA, Piggot PJ, Role of intracellular polysaccharide in persistence of Streptococcus mutans. J Bacteriol 191:23(7315-22)2009 Dec

19578359. Eldar A, Chary VK, Xenopoulos P, Fontes ME, Losón OC, Dworkin J, Piggot PJ, Elowitz MB, Partial penetrance facilitates developmental evolution in bacteria. Nature 460:7254(510-4)2009 Jul 23

17921305. Chary VK, Xenopoulos P, Piggot PJ, Expression of the sigmaF-directed csfB locus prevents premature appearance of sigmaG activity during sporulation of Bacillus subtilis. J Bacteriol 189:23(8754-7)2007 Dec

17322320. Bogush M, Xenopoulos P, Piggot PJ, Separation of chromosome termini during sporulation of Bacillus subtilis depends on SpoIIIE. J Bacteriol 189:9(3564-72)2007 May

17015665. Chary VK, Xenopoulos P, Piggot PJ, Blocking chromosome translocation during sporulation of Bacillus subtilis can result in prespore-specific activation of sigmaG that is independent of sigmaE and of engulfment. J Bacteriol 188:20(7267-73)2006 Oct

16166546. Chary VK, Meloni M, Hilbert DW, Piggot PJ, Control of the expression and compartmentalization of (sigma)G activity during sporulation of Bacillus subtilis by regulators of (sigma)F and (sigma)E. J Bacteriol 187:19(6832-40)2005 Oct

15925458. Chary VK, Busuioc M, Renye JA Jr, Piggot PJ, Vectors that facilitate the replacement of transcriptional lacZ fusions in Streptococcus mutans and Bacillus subtilis with fusions to gfp or gusA. FEMS Microbiol Lett 247:2(171-6)2005 Jun 15

15556029. Piggot PJ, Hilbert DW, Sporulation of Bacillus subtilis. Curr Opin Microbiol 7:6(579-86)2004 Dec

15466565. Renye JA Jr, Piggot PJ, Daneo-Moore L, Buttaro BA, Persistence of Streptococcus mutans in stationary-phase batch cultures and biofilms. Appl Environ Microbiol 70:10(6181-7)2004 Oct

15187183. Hilbert DW, Piggot PJ, Compartmentalization of gene expression during Bacillus subtilis spore formation. Microbiol Mol Biol Rev 68:2(234-62)2004 Jun

15028710. Li Z, Di Donato F, Piggot PJ, Compartmentalization of gene expression during sporulation of Bacillus subtilis is compromised in mutants blocked at stage III of sporulation. J Bacteriol 186:7(2221-3)2004 Apr

15028681. Hilbert DW, Chary VK, Piggot PJ, Contrasting effects of sigmaE on compartmentalization of sigmaF activity during sporulation of Bacillus subtilis. J Bacteriol 186:7(1983-90)2004 Apr

12591876. Hilbert DW, Piggot PJ, Novel spoIIE mutation that causes uncompartmentalized sigmaF activation in Bacillus subtilis. J Bacteriol 185:5(1590-8)2003 Mar

12533463. Chary VK, Piggot PJ, Postdivisional synthesis of the Sporosarcina ureae DNA translocase SpoIIIE either in the mother cell or in the prespore enables Bacillus subtilis to translocate DNA from the mother cell to the prespore. J Bacteriol 185:3(879-86)2003 Feb

12399511. Minkovsky N, Zarimani A, Chary VK, Johnstone BH, Powell BS, Torrance PD, Court DL, Simons RW, Piggot PJ, Bex, the Bacillus subtilis homolog of the essential Escherichia coli GTPase Era, is required for normal cell division and spore formation. J Bacteriol 184:22(6389-94)2002 Nov

11606741. Li Z, Piggot PJ, Development of a two-part transcription probe to determine the completeness of temporal and spatial compartmentalization of gene expression during bacterial development. Proc Natl Acad Sci U S A 98:22(12538-43)2001 Oct 23

11371526. Amaya E, Khvorova A, Piggot PJ, Analysis of promoter recognition in vivo directed by sigma(F) of Bacillus subtilis by using random-sequence oligonucleotides. J Bacteriol 183:12(3623-30)2001 Jun

11292820. Sciochetti SA, Blakely GW, Piggot PJ, Growth phase variation in cell and nucleoid morphology in a Bacillus subtilis recA mutant. J Bacteriol 183:9(2963-8)2001 May

11208805. Sciochetti SA, Piggot PJ, Blakely GW, Identification and characterization of the dif Site from Bacillus subtilis. J Bacteriol 183:3(1058-68)2001 Feb

11037128. Sciochetti SA, Piggot PJ, A tale of two genomes: resolution of dimeric chromosomes in Escherichia coli and Bacillus subtilis. Res Microbiol 151:7(503-11)2000 Sep

10913074. Khvorova A, Chary VK, Hilbert DW, Piggot PJ, The chromosomal location of the Bacillus subtilis sporulation gene spoIIR is important for its function. J Bacteriol 182:16(4425-9)2000 Aug

10672183. Chary VK, Hilbert DW, Higgins ML, Piggot PJ, The putative DNA translocase SpoIIIE is required for sporulation of the symmetrically dividing coccal species Sporosarcina ureae. Mol Microbiol 35:3(612-22)2000 Feb

10551166. Cappiello MG, Hantman MJ, Zuccon FM, Peruzzi F, Amjad M, Piggot PJ, Daneo-Moore L, Physical and genetic map of Streptococcus mutans GS-5 and localization of five rRNA operons. Oral Microbiol Immunol 14:4(225-32)1999 Aug

10537218. Schuch R, Garibian A, Saxild HH, Piggot PJ, Nygaard P, Nucleosides as a carbon source in Bacillus subtilis: characterization of the drm-pupG operon. Microbiology 145 ( Pt 10):(2957-66)1999 Oct

10498718. Sciochetti SA, Piggot PJ, Sherratt DJ, Blakely G, The ripX locus of Bacillus subtilis encodes a site-specific recombinase involved in proper chromosome partitioning. J Bacteriol 181:19(6053-62)1999 Oct

9696765. Karow ML, Rogers EJ, Lovett PS, Piggot PJ, Suppression of TGA mutations in the Bacillus subtilis spoIIR gene by prfB mutations. J Bacteriol 180:16(4166-70)1998 Aug

9622350. Henriques AO, Glaser P, Piggot PJ, Moran CP Jr, Control of cell shape and elongation by the rodA gene in Bacillus subtilis. Mol Microbiol 28:2(235-47)1998 Apr

9495766. Khvorova A, Zhang L, Higgins ML, Piggot PJ, The spoIIE locus is involved in the Spo0A-dependent switch in the location of FtsZ rings in Bacillus subtilis. J Bacteriol 180:5(1256-60)1998 Mar

9350865. Zhang L, Higgins ML, Piggot PJ, The division during bacterial sporulation is symmetrically located in Sporosarcina ureae. Mol Microbiol 25:6(1091-8)1997 Sep

9252583. Chary VK, Amaya EI, Piggot PJ, Neomycin- and spectinomycin-resistance replacement vectors for Bacillus subtilis. FEMS Microbiol Lett 153:1(135-9)1997 Aug 1

9043134. Whalen MB, Piggot PJ, Gain-of-function mutation of sapB that affects formation of alkaline phosphatase by Bacillus subtilis in sporulation conditions. Microbiology 143 ( Pt 2):(577-83)1997 Feb

8939730. Piggot PJ, Spore development in Bacillus subtilis. Curr Opin Genet Dev 6:5(531-7)1996 Oct

8631668. Zhang L, Higgins ML, Piggot PJ, Karow ML, Analysis of the role of prespore gene expression in the compartmentalization of mother cell-specific gene expression during sporulation of Bacillus subtilis. J Bacteriol 178:10(2813-7)1996 May

7592464. Yu J, Hederstedt L, Piggot PJ, The cytochrome bc complex (menaquinone:cytochrome c reductase) in Bacillus subtilis has a nontraditional subunit organization. J Bacteriol 177:23(6751-60)1995 Dec

7557481. Karow ML, Piggot PJ, Construction of gusA transcriptional fusion vectors for Bacillus subtilis and their utilization for studies of spore formation. Gene 163:1(69-74)1995 Sep 22

7892217. Karow ML, Glaser P, Piggot PJ, Identification of a gene, spoIIR, that links the activation of sigma E to the transcriptional activity of sigma F during sporulation in Bacillus subtilis. Proc Natl Acad Sci U S A 92:6(2012-6)1995 Mar 14

8586211. Zuccon FM, Hantman MJ, Sechi LA, Sun S, Piggot PJ, Daneo-Moore L, Physical map of Streptococcus mutans GS-5 chromosome. Dev Biol Stand 85:(403-7)1995

8088554. Birkey SM, Sun G, Piggot PJ, Hulett FM, A pho regulon promoter induced under sporulation conditions. Gene 147:1(95-100)1994 Sep 15

7952182. Moldover B, Cao L, Piggot PJ, Identification of a control region for expression of the forespore-specific Bacillus subtilis locus spoVA. Microbiology 140 ( Pt 9):(2299-304)1994 Sep

8021191. Schuch R, Piggot PJ, The dacF-spoIIA operon of Bacillus subtilis, encoding sigma F, is autoregulated. J Bacteriol 176:13(4104-10)1994 Jul

8188591. Bylund JE, Zhang L, Haines MA, Higgins ML, Piggot PJ, Analysis by fluorescence microscopy of the development of compartment-specific gene expression during sporulation of Bacillus subtilis. J Bacteriol 176:10(2898-905)1994 May

7681431. Bylund JE, Haines MA, Piggot PJ, Higgins ML, Axial filament formation in Bacillus subtilis: induction of nucleoids of increasing length after addition of chloramphenicol to exponential-phase cultures approaching stationary phase. J Bacteriol 175:7(1886-90)1993 Apr

8450309. Hantman MJ, Sun S, Piggot PJ, Daneo-Moore L, Chromosome organization of Streptococcus mutans GS-5. J Gen Microbiol 139:1(67-77)1993 Jan

1447970. Higgins ML, Piggot PJ, Septal membrane fusion--a pivotal event in bacterial spore formation? Mol Microbiol 6:18(2565-71)1992 Sep

1629150. Wu JJ, Schuch R, Piggot PJ, Characterization of a Bacillus subtilis sporulation operon that includes genes for an RNA polymerase sigma factor and for a putative DD-carboxypeptidase. J Bacteriol 174:15(4885-92)1992 Aug

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laboratory personnel :


Associate Scientist

Vasant Kumar Chary, PhD


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graduate students :


Monica Busuioc

Deepa Mothey

Genevieve Regan

April Suriano (Co-advisor, Bettina A. Buttaro, PhD)

Panagiotis Xenopoulos


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