Applied Microbiology and Biotechnology

, Volume 75, Issue 1, pp 133–140 | Cite as

Cellulose biosynthesis pathway is a potential target in the improved treatment of Acanthamoeba keratitis

  • Ricky Dudley
  • Selwa Alsam
  • Naveed Ahmed KhanEmail author
Applied Microbial and Cell Physiology


Acanthamoeba is an opportunistic protozoan pathogen that can cause blinding keratitis as well as fatal granulomatous encephalitis. One of the distressing aspects in combating Acanthamoeba infections is the prolonged and problematic treatment. For example, current treatment against Acanthamoeba keratitis requires early diagnosis followed by hourly topical application of a mixture of drugs that can last up to a year. The aggressive and prolonged management is due to the ability of Acanthamoeba to rapidly adapt to harsh conditions and switch phenotypes into a resistant cyst form. One possibility of improving the treatment of Acanthamoeba infections is to inhibit the ability of these parasites to switch into the cyst form. The cyst wall is partially made of cellulose. Here, we tested whether a cellulose synthesis inhibitor, 2,6-dichlorobenzonitrile (DCB), can enhance the effects of the antiamoebic drug pentamidine isethionate (PMD). Our findings revealed that DCB can block Acanthamoeba encystment and may improve the antiamoebic effects of PMD. Using in vitro assays, the findings revealed that DCB enhanced the inhibitory effects of PMD on Acanthamoeba binding to and cytotoxicity of the host cells, suggesting the cellulose biosynthesis pathway as a novel target for the improved treatment of Acanthamoeba infections.


Acanthamoeba Cysts Therapy Encystment Pentamidine 2,6-Dichlorobenzonitrile 


  1. Afeltra J, Meis JF, Vitale RG, Mouton JW, Verweij PE, Eurofung Network (2002) In vitro activities of pentamidine, pyrimethamine, trimethoprim, and sulfonamides against Aspergillus species. Antimicrob Agents Chemother 46:2029–2031CrossRefGoogle Scholar
  2. Alsam S, Kim KS, Stins M, Rivas AO, Sissons J, Khan NA (2003) Acanthamoeba interactions with human brain microvascular endothelial cells. Microb Pathog 35:235–241CrossRefGoogle Scholar
  3. Byers TJ (1979) Growth, reproduction, and differentiation in Acanthamoeba. Int Rev Cytol Suppl 61:283–338CrossRefGoogle Scholar
  4. Chourey PS, Taliercio EW, Kane EJ (1991) Tissue-specific expression and anaerobically induced posttranscriptional modulation of sucrose synthase genes in Sorghum bicolor M. Plant Physiol 96:485–490Google Scholar
  5. Cordingley JS, Wills RA, Villemez CL (1996) Osmolarity is an independent trigger of Acanthamoeba castellanii differentiation. J Cell Biochem 61:167–171CrossRefGoogle Scholar
  6. Del Gallo M, Negi M, Neyra CA (1989) Calcofluor- and lectin-binding exocellular polysaccharides of Azospirillum brasilense and Azospirillum lipoferum. J Bacteriol 171:3504–3510Google Scholar
  7. Delmer DP, Amor Y (1995) Cellulose biosynthesis. Plant Cell 7:987–1000CrossRefGoogle Scholar
  8. Delmer DP, Read SM, Cooper G (1987) Identification of a receptor protein in cotton fibers for the herbicide 2,6-dichlorobenzonitrile. Plant Physiol 84:415–420CrossRefGoogle Scholar
  9. Dudley R, Matin A, Alsam S, Sissons J, Mahsood AH, Khan NA (2005) Acanthamoeba isolates belonging to T1, T2, T3, T4 but not T7 encyst in response to increased osmolarity and cysts do not bind to human corneal epithelial cells. Acta Trop 95:100–108CrossRefGoogle Scholar
  10. Elorza MV, Rico H, Sentandreu R (1983) Calcofluor White alters the assembly of chitin fibrils in Saccharomyces cerevisiae and Candida albicans cells. J Gen Microbiol 129:1577–1582Google Scholar
  11. Haigler CH, Brown RM, Benziman M (1980) Calcofluor White ST alters the in vivo assembly of microfibrils. Science 210:903–906CrossRefGoogle Scholar
  12. Haigler CH, White AR, Brown M, Cooper KM (1982) Alteration of in vivo cellulose ribbon assembly by carboxymethlycellulose and other cellulose derivatives. J Cell Biol 94:64–69CrossRefGoogle Scholar
  13. Heim DR, Skomp JR, Tschabold EE, Larrinua IM (1990) Isoxaben inhibits the synthesis of acid insoluble cell wall materials in Arabidopsis thaliana. Plant Physiol 93:695–700Google Scholar
  14. Herth W (1980) Calcoflour White and Congo Red inhibit chitin microfibril assembly of Poterioochromonas: Evidence for a gap between polymerization and microfibril formation. J Cell Biol 87:442–450CrossRefGoogle Scholar
  15. Khan NA (2006) Acanthamoeba: biology and increasing importance in human health. FEMS Microbiol Rev 30:564–595CrossRefGoogle Scholar
  16. Khunkitti W, Lloyd D, Furr JR, Russell AD (1998) Acanthamoeba castellanii: growth, encystment, excystment and biocide susceptibility. J Infect 36:43–48CrossRefGoogle Scholar
  17. Leher H, Silvany R, Alizadeh H, Huang J, Niederkorn JY (1998) Mannose induces release of cytopathic factors from Acanthamoeba castellanii. Infect Immun 66:5–10Google Scholar
  18. Maas C, Schaal S, Werr W (1990) A feedback control element near the transcription start site of the maize Shrunken gene determines promoter activity. EMBO J 9:3447–3452Google Scholar
  19. Marciano-Cabral F, Cabral G (2003) Acanthamoeba spp. as agents of disease in humans. Clin Microbiol Rev 16:273–307CrossRefGoogle Scholar
  20. Mazur T, Hadas E, Iwanicka I (1995) The duration of the cyst stage and the viability and virulence of Acanthamoeba isolates. Trop Med Parasitol 46:106–108Google Scholar
  21. Miletti KE, Leibowitz MJ (2000) Pentamidine inhibition of group 1 intron splicing in Candida albicans correlates with growth inhibition. Antimicrob Agents Chemother 44:958–966CrossRefGoogle Scholar
  22. Mizuta S, Brown RM (1992) Effects of 2,6-dichlorobenzonitrile and Tinopal LPW on the structure of the cellulose synthesizing complex of Vaucheria hamata. Protoplasma 166:200–207CrossRefGoogle Scholar
  23. Neff RJ, Neff RH (1969) The biochemistry of amoebic encystment. Symp Soc Exp Biol 23:51–81Google Scholar
  24. Niederkorn JY, Alizadeh H, Leher H, McCulley JP (1999) The pathogenesis of Acanthamoeba keratitis. Microbes Infect 1:437–443CrossRefGoogle Scholar
  25. Perez-Santonja JJ, Kilvington S, Hughes R, Tufail A, Metheson M, Dart JKG (2003) Persistently culture positive Acanthamoeba keratitis; in vivo resistance and in vitro sensitivity. Ophthalmology 110:1593–1600CrossRefGoogle Scholar
  26. Potter JL, Weisman RA (1971) Differentiation in Acanthamoeba: β-glucan synthesis during encystment. Biochim Biophys Acta 237:65–74Google Scholar
  27. Potter JL, Weisman RA (1972) Correlation of cellulose synthesis in vivo and in vitro during the encystment of Acanthamoeba. Develop Biol 28:472–479CrossRefGoogle Scholar
  28. Roncero C, Durán A (1985) Effect of Calcofluor White and Congo red on fungal cell wall morphogenesis: In vivo activation of chitin polymerization. J Bacteriol 163:1180–1185Google Scholar
  29. Ross P, Mayer R, Weinhouse H, Amikan D, Huggirat Y, Benziman M (1990) The cyclic diguanylic acid regulatory system of cellulose synthesis in Acetobacter xylinum. J Biol Chem 265:18933–18943Google Scholar
  30. Ross P, Mayer R, Benziman M (1991) Cellulose biosynthesis and function in bacteria. Microbiol Rev 55:35–58Google Scholar
  31. Saxena IM, Brown MR, Dandekar T (2001) Structure–function characterisation of cellulose synthase: relationship to other glycosyltransferases. Phytochemistry 57:1135–1148CrossRefGoogle Scholar
  32. Sharma S, Garg P, Rao GN (2000) Patient characteristics, diagnosis and treatment of non-contact lens related Acanthamoeba keratitis. Br J Ophthalmol 84:1103–1108CrossRefGoogle Scholar
  33. Sissons J, Alsam S, Jayasekera S, Kim KS, Stins M, Khan NA (2004) Acanthamoeba induces cell-cycle arrest in the host cells. J Med Microbiol 53:711–717CrossRefGoogle Scholar
  34. Sissons J, Kim KS, Stins M, Jayasekera S, Alsam S, Khan NA (2005) Acanthamoeba castellanii induces host cell death via a phosphatidylinositol 3-kinase-dependent mechanism. Infect Immun 73:2704–2708CrossRefGoogle Scholar
  35. Stins MF, Gilles F, Kim KS (1997) Selective expression of adhesion molecules on human brain microvascular endothelial cells. J Neuroimmunol 76:81–90CrossRefGoogle Scholar
  36. Tomlinson G, Jones EA (1962) Isolation of cellulose from the cyst wall of a soil amoeba. Biochim Biophys Acta 63:194–200CrossRefGoogle Scholar
  37. Turner NA, Russell AD, Furr JR, Lloyd D (2000) Emergence of resistance to biocides during differentiation of Acanthamoeba castellanii. J Antimicrob Chemother 46:27–34CrossRefGoogle Scholar
  38. Weisman RA (1976) Differentiation in Acanthamoeba castellanii. Ann Rev Microbiol 30:189–219CrossRefGoogle Scholar
  39. Wang Y, Lu J, Mollet JC, Gretz MR, Hoagland KD (1997) Extracellular matrix assembly in diatoms (Bacillariophyceae). II. 2,6-Dichlorobenzonitrile inhibition of motility and stalk production in the marine diatom Achnanthes longipes. Plant Physiol 113:1071–1080CrossRefGoogle Scholar
  40. Yu X, Atalla RH (1996) Production of cellulose Π by Acetobacter xylinum in the presence of 2,6-dichlorobenzonitrile. Int J Biol Macromol 19:145–146CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.School of Biological and Chemical Sciences, Birkbeck CollegeUniversity of LondonLondonUK

Personalised recommendations