title: Dual effects of single-walled carbon nanotubes coupled with near-infrared radiation on Bacillus anthracis spores: inactivates spores and stimulates the germination of surviving spores.
abstract: BACKGROUND
  Bacillus anthracis is a pathogen that causes life-threatening disease--anthrax. B. anthracis spores are highly resistant to extreme temperatures and harsh chemicals. Inactivation of B. anthracis spores is important to ensure the environmental safety and public health. The 2001 bioterrorism attack involving anthrax spores has brought acute public attention and triggered extensive research on inactivation of B. anthracis spores. Single-walled carbon nanotubes (SWCNTs) as a class of emerging nanomaterial have been reported as a strong antimicrobial agent. In addition, continuous near infrared (NIR) radiation on SWCNTs induces excessive local heating which can enhance SWCNTs' antimicrobial effect. In this study, we investigated the effects of SWCNTs coupled with NIR treatment on Bacillus anthracis spores.
  
  
  CONCLUSIONS
  The results showed that the treatment of 10 μg/mL SWCNTs coupled with 20 min NIR significantly improved the antimicrobial effect by doubling the percentage of viable spore number reduction compared with SWCNTs alone treatment (88% vs. 42%). At the same time, SWCNTs-NIR treatment activated the germination of surviving spores and their dipicolinic acid (DPA) release during germination. The results suggested the dual effect of SWCNTs-NIR treatment on B. anthracis spores: enhanced the sporicidal effect and stimulated the germination of surviving spores. Molecular level examination showed that SWCNTs-NIR increased the expression levels (>2-fold) in 3 out of 6 germination related genes tested in this study, which was correlated to the activated germination and DPA release. SWCNTs-NIR treatment either induced or inhibited the expression of 3 regulatory genes detected in this study. When the NIR treatment time was 5 or 25 min, there were 3 out of 7 virulence related genes that showed significant decrease on expression levels (>2 fold decrease).
  
  
  CONCLUSIONS
  The results of this study demonstrated the dual effect of SWCNTs-NIR treatment on B. anthracis spores, which enhanced the sporicidal effect and stimulated the germination of surviving spores. SWCNTs-NIR treatment also altered the expression of germination, regulatory, and virulence-related genes in B. anthracis.
authors: Biomanufacturing Research Institute and Technology Enterprise (BRITE) and Department of Pharmaceutical Sciences, North Carolina Central University, Durham, NC 27707, USA.
authors: Xiuli
authors: X
authors: Dong
authors: Department of Mathematics and Physics, North Carolina Central University, Durham, NC 27707, USA.
authors: Yongan
authors: Y
authors: Tang
authors: Department of Mathematics and Physics, North Carolina Central University, Durham, NC 27707, USA.
authors: Marvin
authors: M
authors: Wu
authors: Department of Mathematics and Physics, North Carolina Central University, Durham, NC 27707, USA.
authors: Branislav
authors: B
authors: Vlahovic
authors: Biomanufacturing Research Institute and Technology Enterprise (BRITE) and Department of Pharmaceutical Sciences, North Carolina Central University, Durham, NC 27707, USA.
authors: Liju
authors: L
authors: Yang
keywords: Bacillus anthracis spores; Dipicolinic acid; Gene expression; Germination; Near infrared radiation; Single walled carbon nanotubes
references: J Bacteriol. 2005 Dec;187(23):8055-62
references: 16291679
references: J Bacteriol. 1964 Dec;88:1774-89
references: 14240968
references: Water Res. 2009 Jan;43(1):148-56
references: 18929383
references: Infect Immun. 2005 Aug;73(8):5222-8
references: 16041044
references: Langmuir. 2009 Mar 3;25(5):3003-12
references: 19437709
references: Proc Natl Acad Sci U S A. 2005 Aug 16;102(33):11600-5
references: 16087878
references: J Appl Microbiol. 2005;99(6):1484-94
references: 16313421
references: Science. 2002 Dec 20;298(5602):2361-6
references: 12459549
references: Methods. 2001 Dec;25(4):402-8
references: 11846609
references: Science. 2002 Apr 26;296(5568):705
references: 11976446
references: J Bacteriol. 2007 Apr;189(8):3296-301
references: 17277068
references: Environ Sci Technol. 2009 Apr 1;43(7):2648-53
references: 19452930
references: Environ Toxicol Chem. 2005 Nov;24(11):2757-62
references: 16398110
references: Langmuir. 2010 Oct 19;26(20):16013-9
references: 20849142
references: Environ Sci Technol. 2008 Oct 1;42(19):7528-34
references: 18939597
references: Appl Environ Microbiol. 2006 Oct;72(10):6808-14
references: 17021233
references: Langmuir. 2008 Jun 1;24(13):6409-13
references: 18512881
references: Microbiology (Reading). 2010 Feb;156(Pt 2):385-391
references: 19926656
references: Water Res. 2008 Nov;42(18):4591-602
references: 18804836
references: J Bacteriol. 2010 Jul;192(13):3424-33
references: 20435722
references: Emerg Infect Dis. 2003 Jun;9(6):623-7
references: 12780999
references: Am J Physiol Lung Cell Mol Physiol. 2005 Nov;289(5):L698-708
references: 15951334
references: Langmuir. 2007 Aug 14;23(17):8670-3
references: 17658863
references: Curr Issues Mol Biol. 2010;12(3):147-58
references: 20472940
references: Science. 2002 Jul 26;297(5581):593-6
references: 12142535
references: Curr Opin Microbiol. 2003 Dec;6(6):550-6
references: 14662349
references: Curr Issues Mol Biol. 2006 Jan;8(1):51-62
references: 16450885
references: Environ Sci Technol. 2012 Dec 18;46(24):13417-24
references: 23167544
references: Environ Sci Technol. 2010 Apr 1;44(7):2412-8
references: 20184360
references: J Bacteriol. 2000 May;182(9):2513-9
references: 10762253
references: Nature. 2003 May 1;423(6935):81-6
references: 12721629
references: J Am Chem Soc. 2006 Oct 18;128(41):13364-5
references: 17031942
references: Environ Toxicol Chem. 2008 Sep;27(9):1825-51
references: 19086204
references: J Nanosci Nanotechnol. 2012 May;12(5):3821-30
references: 22852312
references: Appl Environ Microbiol. 2008 Dec;74(24):7669-74
references: 18836020
references: Nanoscale. 2010 Dec;2(12):2744-50
references: 20877897
references: ACS Nano. 2009 Dec 22;3(12):3891-902
references: 19894705
references: Res Microbiol. 2010 Nov;161(9):735-42
references: 20863885
references: Lett Appl Microbiol. 1996 Nov;23(5):290-4
references: 8987707
references: Environ Sci Technol. 2005 Jun 1;39(11):4307-16
references: 15984814
references: J Bacteriol. 2002 Feb;184(4):1219-24
references: 11807087
references: J Microsc. 2000 Nov;200(Pt 2):83-104
references: 11106949
references: Int J Food Microbiol. 2009 Aug 15;133(3):213-6
references: 19540610
references: J Nanosci Nanotechnol. 2011 Jun;11(6):4708-16
references: 21770096
references: Infect Immun. 2007 Jul;75(7):3434-44
references: 17470545
references: J Food Sci. 2009 Apr;74(3):M120-4
references: 19397727