胃幽門螺旋桿菌 (Helicobacter pylori) 為螺旋狀、微耗氧、革蘭氏陰性細菌。全世界超過50%的人口受此菌感染，是一種人類重要的病原菌。受感染者可能會衍生多種胃部相關之疾病，例如：胃及十二指腸潰瘍、胃癌、黏膜相關淋巴組織淋巴瘤等疾病。脂多醣 (Lipopolysaccharide, LPS) 是革蘭氏陰性菌外膜的主要成分，可以維持細菌外膜的完整性，並且保護細菌不受毒性和疏水性物質攻擊，例如：清潔劑以及脂溶性抗生素等物質。脂多醣由三部分組成，分別是：脂質A (lipid A) 、核心多醣 (core oligosaccharide) 以及O-抗原 (O-antigen polysaccharide) 。在胃幽門螺旋桿菌脂多醣中的O-antigen具有Lewis antigen，其可以模仿人類胃部細胞的多聚醣結構，幫助細菌逃脫人類的免疫系統並且造成慢性感染。
在本篇研究中，我們研究三種被認為與胃幽門螺旋桿菌脂多醣中O抗原之生合成有關的基因，分別是wecA、wzk以及waaL。在近期被提出的模型中，胃幽門螺旋桿菌脂多醣的生合成可能是透過一種需要Wzk參與的路徑；其中WecA (HP1581) 是一個可以將UDP-GlcNAc轉移到UndP脂質載體上的起始酵素，而整個O抗原的合成發生在細胞質。隨後Wzk (HP1206) 翻轉酶會將O抗原轉位到周質，其後WaaL (HP1039) 連接酶會將O抗原與核心多醣-脂質A結合起來產生完整的脂多醣。生物資訊分析的結果指出HP1581是屬於內膜蛋白質，能使 UDP-GlcNAc殘基轉移到UndP脂質載體上；HP1206和位在內膜的Wzk翻轉酶具有高度同源性，而且與其他革蘭氏陰性菌中脂多醣生合成的Wzk-dependent路徑有所關聯性；此外胃幽門螺旋桿菌26695中的HP1039可能是一個具有特殊功能的內膜蛋白質。為了探討HP1581、HP1206及HP1039對於脂多醣之生合成和感染的功能特性，我們建構了相對應的突變菌株並且研究其表型特性。利用銀染分析以及免疫墨點法去偵測Lewis X抗原的結果顯示這些突變菌株皆有O抗原的缺失。利用免疫墨點法去偵測Lewis Y抗原的結果則暗示在胃幽門螺旋桿菌26695中某些酵素活性會去彌補缺失的酵素功能。研究也發現這三株功能缺失突變菌株在生長曲線的死亡期時會降低生存能力。此外，與正常菌株相比，HP1206及HP1039突變菌株對SDS和抗生素novobiocin較敏感，而HP1581突變菌株則沒有顯著差異。總而言之，本篇研究報告中所獲得的知識將有助於發現新標的以利於往後開發對抗胃幽門螺旋桿菌感染的藥物。

Helicobacter pylori is a spiral-shaped microaerophilic gram-negative bacterium and is recognized as a notorious human pathogen that infects a half of the world’s human population. Several human stomach diseases such as gastric ulcer, gastroduodenal ulcer, gastric adenocarcinoma and mucosa-associated lymphatic tissue (MALT) lymphoma are related with H. pylori infection. Lipopolysaccharide (LPS) is a major component on the surface of gram-negative bacteria including H. pylori and plays an important role in maintaining the integrity of bacterial outer membrane as well as providing a protective barrier against the entry of toxic hydrophobic compounds such as detergents and lipophilic antibiotics. LPS is composed of lipid A, core oligosaccharide and O-antigen polysaccharide. O-antigen of H. pylori LPS contains Lewis antigens which mimic glycan structures produced by human gastric cells leading to escape from host immune response and chronic infection. In this study, we investigated three genes including wecA, wzk and waaL which are putatively related to H. pylori LPS O-antigen biosynthesis. In a recently proposed model, H. pylori LPS biosynthesis follows a novel Wzy-dependent pathway and WecA (HP1581) is an initiating enzyme to transfer UDP-GlcNAc onto the UndP lipid carrier. The synthesis of entire O-antigen occurs in the cytoplasm which later is translocated to the periplasm by flippase WzK (HP1206) and ligated with core-lipid A by ligase WaaL (HP1039) to form the complete LPS. These bioinformatic results indicated that HP1581 is an inner membrane protein and responsible for transferring a UDP-GlcNAc residue onto the UndP lipid carrier; HP1206 has high homology with wzk flippase located in the inner membrane which is related to the Wzy-dependent pathway of LPS biosynthesis in other gram-negative bacteria; and HP1039 is likely an inner membrane protein with an unique function in H. pylori 26695. To further characterize the functional role of HP1581, HP1206 and HP1039 in the LPS biosynthesis and infection, the corresponding H. pylori knockout mutants, ΔHP1581, ΔHP1206 and ΔHP1039 are constructed and their phenotypic properties were characterized. These H. pylori 26695 knockout mutants all showed the deficiency of O-antigens when analyzed by silver staining and immunoblotting for the anti-Lewis X determinant. The immunoblotting result with anti-Lewis Y determinant suggested that the lost enzymes may be compensated by certain enzymatic activities in H. pylori 26695. The three knockout mutants have reduced the survival ability in the death phase of growth. In addition, ΔHP1206 and ΔHP1039 have increased the sensitivity to SDS and novobiocin while ΔHP1581 shows no significant difference compared to that of the wild-type H. pylori 26695. In conclusion, we hope that the obtained knowledge from this study would be useful to discover attractive targets for the development of inhibitors or antimicrobial agents to manage H. pylori infection.

1. Hofman, P., Waidner, B., Hofman, V., Bereswill, S., Brest, P., Kist, M. (2004). Pathogenesis of Helicobacter pylori infection. Helicobacter. 9(1): 15-22.
2. Buckley, M.J., O’Morain, C.A. (1998). Helicobacter biology – discovery. British Medical Bulletin. 54(1): 7-16.
3. Suerbaum, S. (1995). The complex flagella of gastric Helicobacter species. Trends in Microbiology. 3(5): 168-70.
4. Johannes, G.K., Arnoud, H.M., Ernst, J.K. (2006). Pathogenesis of Helicobacter pylori infection. Clinical Microbiology Reviews. 19(3): 449-490.
5. Spohn, G., Scarlato, V. (2001). Motility, Chemotaxis, and Flagella. Helicobacter pylori: Physiology and Genetics. Washington (DC): American Society for Microbiology Press, Chapter 21.
6. Yan, J., Liang, S.H., Mao, Y.F., Li, L.W., Li, S.P. (2003). Construction of expression systems for flaA and flaB genes of Helicobacter pylori and determination of immunoreactivity and antigenicity of recombinant proteins. World Journal Gastroenterol. 9(10): 2240-50.
7. Kim, J.S., Chang, J.H., Chung, S.I., Yum, J.S. (1999). Molecular cloning and characterization of the Helicobacter pylori fliD gene, an essential factor in flagellar structure and motility. Journal of Bacteriology. 181(2): 6969-76.
8. Flint, A., Stintzi, A., Saraiva, L.M. (2016). Oxidative and nitrosative stress defences of Helicobacter and Campylobacter species that counteract mammalian immunity. FEMS Microbiology Reviews. 40(6): 938-960.
9. Whary, M.T., Fox, J.G. (2004). Natural and experimental Helicobacter infections. Comparative Medicine. 54(2): 128-58.
10. Stenstrom, B., Windsor, H.M., Fulurija, A., Benghezal, M., Kumarasinghe, M.P., Kimura, K., Tay, C.Y., Viiala, C.H., Ee, H.C., Lu, W., Schoep, T.D., Webberley, K.M., Marshall, B.J. (2016). Helicobacter pylori overcomes natural immunity in repeated infections. Clinical Case Reports. 4(11): 1026-1033.
11. Barry, M. (2016). A brief history of the discovery of Helicobacter pylori. Springer Japan 2016. Chapter 1.
12. Blanchard, T.G., Czinn, S.J., Correa, P., Nakazawa, T., Keelan, M., Morningstar, L., Santana, C.I., Maroo, A., McCracken, C., Shefchek, K., Daugherty, S., Song, Y., Fraser, C.M., Fricke, W. F. (2013). Genome sequences of 65 Helicobacter pylori strains isolated from asymptomatic individuals and patients with gastric cancer, peptic ulcer disease, or gastritis. Pathogens and Disease. 68(2): 39-43.
13. Fitzgerald, J.R., Musser, J.M. (2001). Evolutionary genomics of pathogenic bacteria. Trends in Microbiology. 9(11): 547-53.
14. Ahmed, N., Loke, M.F., Kumar, N., Vadivelu, J. (2013). Helicobacter pylori in 2013: Multiplying genomes, emerging insights. Helicobacter. 18(1): 1-4.
15. O’Morain, N.R., Dore, M.P., O’Connor, A.J.P., Gisbert, J.P., O’Morain, C.A. (2018). Treatment of Helicobacter pylori infection in 2018. Helicobacter. 23(1): e12519.
16. Silva, G.M., Silva, H.M., Nascimento, J., Goncalves, J.P., Pereira, F., Lima, R. (2018). Helicobacter pylori antimicrobial resistance in a pediatric population. Helicobacter. 23(5): e12528.
17. Nakamura, H., Yoshiyama, H., Takeuchi, H., Mizote, T., Okita, K., Nakazawa, T. (1998). Urease plays an important role in the chemotactic motility of Helicobacter pylori in a viscous environment. Infection and Immunity. 66(10): 4832-7.
18. Scott, D.R., Weeks, D., Hong, C., Postius, S., Melchers, K., Sachs, G. (1998). The role of internal urease in acid resistance of Helicobacter pylori. Gastroenterology. 114(1): 58-70.
19. JeanMarie Houghton. (2013). Helicobacter species: Methods and Protocols. Springer Protocols 2013. Chapter 3.
20. Schoep, T.D., Fulurija, A., Good, F., Lu, W., Himbeck, R.P., Schwan, C., Choi, S.S., Berg, D.E., Mittl, P.R., Benghezal, M., Marshall, B.J. (2010). Surface properties of Helicobacter pylori urease complex are essential for persistence. Plos One. 5(11): e15042.
21. Kao, C.Y., Sheu, B.S., Wu, J.J. (2016). Helicobacter pylori infection: An overview of bacterial virulence factors and pathogenesis. Biomedical Journal. 39(1): 14-23.
22. Lertsethtakarn, P., Ottemann, K. M., Hendrixson, D. R. (2011). Motility and chemotaxis in Campylobacter and Helicobacter. Annu Rev Microbiol. 65: 389-410.
23. Schoenhofen, I. C., Lunin, V. V., Julien, J. P., Li, Y., Ajamian, E., Matte, A. (2006). Structural and functional characterization of PseC, an aminotransferase involved in the biosynthesis of pseudaminic acid, an essential flagellar modification in Helicobacter pylori. Biol Chem. 281(13): 8970-16.
24. Abadi, A.T.B. (2017). Strategies used by Helicobacter pylori to establish persistent infection. World Journal of Gastroenterology. 23(16): 2870-2882.
25. Li, N., Feng, Y., Hu, Y., He, C., Xie, C., Ouyang, Y., Artim, S.C., Huang, D., Zhu, Y., Luo, Z., Ge, Z., Lu, N. (2018). Helicobacter pylori CagA promotes epithelial mesenchymal transition in gastric carcinogenesis via triggering oncogenic YAP pathway. Journal of Experimental and Clinical Cancer Research. 37(1): 280.
26. Segal, E. D., Cha, J., Lo, J., Falkow, S., and Tompkins, L. S. (1999). Altered states: Involvement of phosphorylated CagA in the induction of host cellular growth changes by Helicobacter pylori. Proceedings of the National Academy of Sciences of the United States of America. 96(25): 14559-14564.
27. Cover, T. L. and Blaser, M. J. (1992). Purification and characterization of the vacuolating toxin from Helicobacter pylori. The Journal of Biological Chemistry. 267(15): 10570-10575.
28. Cadamuro, A.C., Rossi, A.F., Maniezzo, N.M., Silva, A.E. (2014). Helicobacter pylori infection: Host immune response, implications on gene expression and microRNAs. World Journal of Gastroenterology. 20(6): 1424-37.
29. Nemati, M., Larussa, T., Khorramdelazad, H., Mahmoodi, M., Jafarzadeh, A. (2017). Toll-like receptor 2: An important immunomodulatory molecule during Helicobacter pylori infection. Life Science. 178: 17-29.
30. Ansari, S., Yamaoka, Y. (2017). Helicobacter pylori BabA in adaptation for gastric colonization. World Journal of Gastroenterology. 23(23): 4158-4169.
31. Van A.K., Van A.H., Kusters, J.G., Van, E.A. (2006). Of microbe and man: determinants of Helicobacter pylori-related diseases. FEMS Microbiology Reviews. 30(1): 131-56.
32. Hatakeyama, M. (2017). A sour relationship between BabA and Lewis b. Cell Host and Microbe. 21(3): 318-320.
33. Hage, N., Howard, T., Phillips, C., Brassington, C., Overman, R., Debreczeni, J., Gellert, P., Stolnik, S., Winkler, G.S., Falcone, F.H. (2015). Structural basis of Lewisb antigen binding by the Helicobacter pylori adhesion BabA. Science Advances. 1(7): e1500315.
34. Yamaoka, Y. (2008). Increasing evidence of the role of Helicobacter pylori SabA in the pathogenesis of gastroduodenal disease. Journal of Infection in Developing Countries. 2(3): 174-81.
35. Vivian, C.H., Catherine, R.A., Amy, K.B., Laurence, Z.D., Vanessa, Q.R., Samuel E.h., Mark, H.F. (2014). Repetitive sequence variations in the promoter region of the adhesion-encoding gene sabA of Helicobacter pylori affect transcription. Journal of Bacteriology. 196(19): 3421-3429.
36. Odenbreit, S., Swoboda, K., Barwig, I., Ruhl, S., Boren, T., Koletzko, S., Haas, R. (2009). Outer membrane protein expression profile in Helicobacter pylori clinical isolates. Infection and Immunity. 77(9): 3782-90.
37. Mahboubi, M., Falsafi, T., Sadeghizadeh, M., Mahjoub, F. (2017). The role of outer inflammatory protein A (OipA) in vaccination of the C57BL/6 mouse model infected by Helicobacter pylori. Turish Journal of Medical Sciences. 47(1): 326-333
38. Teymournejad, O., Mobarez, A.M., Hassan, Z.M., Moazzeni, S.M., Ahmadabad, H.N. (2014). In vitro suppression of dendritic cells by Helicobacter pylori OipA. Helicobacter. 19(2): 136-43.
39. Tabassam, F.H., Graham, D.Y., Yamaoka, Y. (2008). OipA plays a role in Helicobacter pylori-induced focal adhesion kinase activation and cytoskeletal re-organization. Cellular Microbiology. 10(4): 1008-20.
40. Magalhaes, A., Reis, C.A. (2010). Helicobacter pylori adhesion to gastric epithelial cells in mediated by glycan receptors. Brazilian Journal of Medical and Biological Research. 43(7): 611-8.
41. Huesca, M., Borgia, S., Hoffman, P., Lingwood, C.A. (1996). Acidic PH changes receptor binding specificity of Helicobacter pylori: a binary adhesion model in which surface heat shock (stress) proteins mediate sulfatide recognition in gastric colonization. Infection and immunity. 64(7): 2643-8.
42. Namavar, F., Sparrius, M., Veerman, E.C., Appelmelk, B.J., Vanderbroucke, C.M. (1998). Neutrophil-activating protein mediates adhesion of Helicobacter pylori to sulfated carbohydrates on high-molecular-weight salivary mucin. Infection and immunity. 66(2): 444-7.
43. Fernandez, G.E., Backert, S. (2014). DNA transfer in the gastric pathogen Helicobacter pylori. Journal of Gastroenterology. 49(4): 594-604.
44. Grohmann, E., Christie, P.J., Waksman, G., Backert, S. (2018). Type IV secretion in Gram-negative and Gram-positive bacteria. Molecular Microbiology. 107(4): 455-471.
45. Ogunyemi, S.O., Fang, Y., Qiu, W., Li, B., Chen, J., Yang, M., Hong, X., Luo, J., Wang, Y., Sun, G. (2018). Role of type IV secretion system genes in virulence of rice bacterial brown stripe pathogen Acidovorax oryzae strain RS-2. Microbial Pathogenesis. 126: 343-350.
46. Yuan, X.Y., Wang, Y., Wang, M.Y. (2018). The type IV secretion system in Helicobacter pylori. Future Microbiology. 13: 1041-1054.
47. Yao, Y., Shen, Y., Zhu, L., Ni, Y., Wang, H., Shao, S. (2018). Preliminary study and bioinformatics analysis on the potential role of CagQ in type IV secretion system of H. pylori. Microbial pathogenesis. 116: 1-7.
48. Yamaoka Y., Kodama, T., Gutierrez, O., Kim, J.G., Kashima, K., Graham, D.Y. (1999). Relationship between Helicobacter pylori iceA, cagA and vacA status and clinical outcome: studies in four different countries. Journal of Clinical Microbiology. 37(7): 2274-9.
49. Wang, H., Yao, Y., Ni, B., Shen, Y., Wang, X., Shen, H., Shao, S. (2016). Helicobacter pylori CagI is associated with the stability of CagA. Microbial Pathogenesis. 99: 130-134.
50. Jean, M. H. (2012). Helicobacter species: Methods and protocols. Human Press. Chapter 7: Page 41,42,43,44,45.
51. Wang, X., Ling, F., Wang, H., Yu, M., Zhu, H., Chen, C., Qian, J., Liu, C., Zhang, Y., Shao, S. (2016). The Helicobacter pylori Cag pathogenicity island protein Cag1 is associated with the function of T4SS. Current Microbiology. 73(1): 22-30.
52. Moretti, E., Collodel, G., Mazzi, L., Campagna, M.S., Figuta, N. (2013). CagA-positive Helicobacter pylori infection and reduced sperm motility, vitality, and normal morphology. Disease Markers. 35(4): 229-34.
53. Yuan, X.Y., Yan, J.J., Yang, Y.C., Wu, C.M., Hu, Y., Geng, J.L. (2017). Helicobacter pylori with East Asian-type cagPAI genes is more virulent than strains with Western-type in some cagPAI genes. Brazilian Journal of Microbiology. 48(2): 218-224.
54. Merino, E., Flores, E.M., Aguilar, G.R. (2017). Functional interaction and structural characteristics of unique components of Helicobacter pylori T4SS. The FEBS Journal. 284(21): 3540-3549.
55. Backert, S., Tegtmeyer, N. (2017). Type IV secretion and signal transduction of Helicobacter pylori CagA through interactions with host cell receptors. Toxins. 9(4): E115.
56. Selbach, M., Moese, S., Hauck, C.R., Meyer, T.F., Backert, S. (2002). Src is the kinase of the Helicobacter pylori CagA protein in vitro and in vivo. The Journal of Biological Chemistry. 277(9): 6775-8.
57. Saadat, I., Higashi, H., Obuse, C., Umeda, M., Murata, K.N., Saito, Y., Lu, H., Ohnishi, N, Azuma, T., Suzuki, A., Ohno, S., Hatakeyama, M. (2007). Helicobacter pylori CagA targets PAR1/MARK kinase to disrupt epithelial cell polarity. Nature. 447(7142): 330-3.
58. Li, N., Tang, B., Jia, Y.P., Zhu. P., Zhuang, Y., Fang, Y., Li, Q., Wang, K., Zhang, W.J., Guo, G., Wang, T.J., Feang, Y.J., Qiao, B., Mao, X.H., Zou, Q.M. (2017). Helicobacter pylori CagA protein negatively regulates autophagy and promotes inflammatory response via c-Met-PI3K/Akt-mTOR signaling pathway. Frontiers in Cellular and Infection Microbiology. 7: 417.
59. Yang, J.J., Yang, J.H., Kim, J., Ma, S.H., Cho, L.Y., Ko, K.P., Shin, A., Choi, B.Y., Kim, H.J., Han, D.S., Eun, C.S., Song, K.S., Kim, Y.S., Chang, S.H., Shin, H.R., Kang, D., Yoo, K.Y., Park, S.K. (2013). Soluble c-Met protein as a susceptible biomarker for gastric cancer risk: A nested case-control study within the Korean multicenter cancer cohort. International Journal of Cancer. 132(9): 2148-56.
60. Suzuki, M., Mimuro, H., Suzuki, T., Park, M., Yamamoto, T., Sasakawa, C. (2005). Interaction of CagA with Crk plays an important role in Helicobacter pylori-induced loss of gastric epithelial cell adhesion. The Journal of experimental Medicine. 202(9): 1235-47.
61. Oliveira, M.J., Costa, A.C., Costa, A.M., Henriques, L., Suriano, G., Atherton, J.C., Machado, J.C., Carneiro, F., Seruca, R., Mareel, M., Leroy, A., Figueiredo, C. (2006). Helicobacter pylori induces gastric epithelial cell invasion in a c-Met and type IV secretion system-dependent manner. The Journal of Biological Chemistry. 281(46): 34888-96.
62. Churin, Y., Al, G.L., Kepp, O., Meyer, T.F., Birchmeier, W., Naumann, M. (2003). Helicobacter pylori CagA protein targets the c-Met receptor and enhances the motogenic response. The Journal of Cell Biology. 161(2): 249-55.
63. Brandt, S., Kwok, T., Hartig, R., Konig, W., Backert, S. (2005). NF-kB activation and potentiation of pro-inflammatory responses by the Helicobacter pylori CagA protein. Proceedings of the National Academy of Sciences of the United States of America. 102(26): 9300-5.
64. Raimo, F., Melanie, M., Nicole, W., Ernst, D.G., Steffen, K., Thilo, K., Michael N. (2008). Host-pathogen systems biology: logical modelling of hepatocyte growth factor and Helicobacter pylori induced c-Met signal transduction. BMC Systems Biology. 2: 4.
65. Suzuki, M., Mimuro, H., Kiga, K., Fukumatsu, M., Ishijima, N., Morikawa, H., Nagai, S., Koyasu, S., Gilman, R.H., Kersulyte, D., Berg, D.E., Sasakawa, C. (2009). Helicobacter pylori CagA phosphorylation-independent function in epithelial proliferation and inflammation. Cell Host and Microbe. 5(1): 23-34.
66. El-Etr, S.H., Mueller, A., Tompkins, L.S., Falkow, S., Merrell, D.S. (2004). Phosphorylation-independent effects of CagA during interaction between Helicobacter pylori and T84 polarized monolayers. The Journal of Infectious Diseases. 190(8): 1516-23.
67. Franco, A.T., Israel, D.A., Washington, M.K., Krishna, U., Fox, J.G., Rogers, A.B., Neish, A.S., Collier, H.J., Perez, P.G., Hatakeyama, M., Whitehead, R., Gaus, K., O’Brien, D.P., Romero, G.J., Peek, R.M. (2005). Activation of β-catenin by carcinogenic Helicobacter pylori. Proceedings of the National Academy of Sciences of the United States of America. 102(30): 10646-51.
68. Clevers, H. (2006). Wnt/β-catenin signaling in development and disease. Cell. 127(3): 469-80.
69. Conacci, S.M., Zhurinsky, J., Ben, Z.A. (2002). The cadherin-catenin adhesion system in signaling and cancer. The Journal of Clinical Investigation. 109(8): 987-91.
70. Segal, E. D., Cha, J., Lo, J., Falkow, S., and Tompkins, L. S. (1999). Altered states: Involvement of phosphorylated CagA in the induction of host cellular growth changes by Helicobacter pylori. Proceedings of the National Academy of Sciences of the United States of America. 96(25): 14559-14564.
71. Palframan, S.L., Kwok, T., Gabriel, K. (2012). Vacuolating cytotoxin A (VacA), a key toxin for Helicobacter pylori pathogenesis. Frontiers in Cellular and Infection microbiology. 2: 92.
72. Torres, V.J., Ivie, S.E., McClain, M.S., Cover, T.L. (2005). Functional properties of the p33 and p55 domains of the Helicobacter pylori vacuolating cytotoxin. The Journal of Biological Chemistry. 280(22): 21107-14.
73. McClain, M.S., Cao, P., Cover, T.L. (2001). Amino-terminal hydrophobic region of Helicobacter pylori vacuolating cytotoxin (VacA) mediates transmembrane protein dimerization. Infection and Immunity. 69(2): 1181-4.
74. Dan, Y., Steven, R. B. (2000). Mutational analysis of the Helicobacter pylori vacuolating toxin amino terminus: identification of amino acids essential for cellular vacuolation. Infection and Immunity. 68(7): 4354-4357.
75. Wang, H.J., Wang, W.C. (2000). Expression and binding analysis of GST-VacA fusions reveals that the C-terminal 100-residue segment of exotoxin is crucial for binding in Hela cells. Biochemical and Biophysical Research Communications. 278(2): 449-54.
76. Wang, W.C., Wang, H.J., Kuo, C.H. (2001). Two distinctive cell binding patterns by vacuolating toxin fused with Glutathione S-transferase: One high-affinity m1-specific binding and the other lower-affinity for variant m forms. Biochemistry. 40(39): 11887-11896.
77. Ildiko, S., Sandra, B., Francesco, T., Monica, M., Barbara, S., John, L.T., Rino, R., Cesare, M., Emanuele, P., Mario, Z. (1999). Formation of anion-selective channels in the cell plasma membrane by the toxin VacA of Helicobacter pylori is required for its biological activity. EMBO press. 18: 5517-5527.
78. Yuko, A., Hajime, I., Kayoko, M., Tsutomu, K., Hitomi, M., Naoyuki, Y., Naota, T., Ken, S., Ken, O., Fuminao, T., Masayuki, N., Joel, M., Toshiya, H., Kazuhiko, N. (2013). Endoplasmic reticulum stress contributes to Helicobacter pylori VacA-induced apoptosis. PloS One. 8(12): e82322.
79. Jain, P., Luo, Z.Q., Blanke, S.R. (2011). Helicobacter pylori vacuolating cytotoxin A (VacA) engages the mitochondrial fission machinery to induce host cell death. Proceedings of the National Academy of Sciences of the United States of America. 108(38): 16032-7.
80. Yamasaki, E., Wada, A., Kumatori, A., Nakagawa, I., Funao, J., Nakayama, M., Hisatsune, J., Kimura, M., Moss, J., Hirayama, T. (2006). Helicobacter pylori vacuolating cytotoxin induces activation of the proapoptotic proteins Bax and Bak, leading to cytochrome C release and cell death, independent of vacuolation. The Journal of Biological Chemistry. 281(16): 11250-9.
81. Marianna, B., Silvia, R.P., Silvia, B., Cristina, U., Laura, P., Dag, I., Amedeo, A., Mario, M.D., John, L.T., Cosima, T.B. (2003). The Helicobacter pylori vacuolating toxin inhibits T cell activation by two independent mechanisms. Journal of Experimental Medicine. 198(12): 1887-1897.
82. Gebert, B., Fischer, W., Weiss, E., Hoffmann, R., Haas, R. (2003). Helicobacter pylori vacuolating cytotoxin inhibits T lymphocyte activation. Science. 301(5636): 1099-102.
83. Torres, V.J., Vancompernolle, S.E., Sundrud, M.S., Unutmaz, D., Cover, T.L. (2007). Helicobacter pylori vacuolating cytotoxin inhibits activation-induced proliferation of human T and B lymphocyte subsets. Journal of Immunology. 179(8): 5433-40.
84. Altherton, J.C., Sharp, P.M., Cover, T.L., Gonzalez, V.G., Peek, R.J., Thompson, S.A., Hawkey, C.J., Blaser, M.J. (1999). Vacuolating cytotoxin (vacA) alleles of Helicobacter pylori comprise two geographically widespread types, m1 and m2, and have evolved through limited recombination. Current Microbiology. 39(4): 211-8.
85. Gonzalez, C.A., Figueiredo, C., Lic, C.B., Ferreira, R.M., Pardo, M.L., Ruiz, L.M., Alonso, P., Sala, N., Capella, G., Sanz-Anquela, J.M. (2011). Helicobacter pylori cagA and vacA genotypes as predictors of progression of gastric preneoplastic lesions: a long-term follow-up in a high-risk area in Spain. The American Journal of Gastroenterology. 106(5): 867-74.
86. Chatterjee, S. N., Chaudhuri, K. (2012). Gram-negative bacteria: The cell membranes. Springer Briefs in Microbiology. 15-34.
87. Moran, A.P. (1996). The role of lipopolysaccharide in Helicobacter pylori pathogenesis. Alimentary Pharmacology and Therapeutics. 10(1): 39-50
88. Nikaido, H. (2003). Molecular basis of bacterial outer membrane permeability revisited. Microbiology and Molecular Biology Reviews. 67(4): 593-656.
89. Li, H., Liao, T., Debowski, A.W., Tang, H., Nilsson, H.O., Stubbs, K.A., Marshall, B.J., Benghezal, M. (2016). Lipopolysaccharide structure and biosynthesis in Helicobacter pylori. Helicobacter. 21(6): 445-461.
90. Leker, K., Loazano, P., Bandyopadhyay, K., Choudhury, B.P., Obonyo, M. (2017). Comparison of lipopolysaccharides composition of two different strains of Helicobacter pylori. BMC Microbiology. 17(1): 226.
91. Fujimoto, Y., Shimoyama, A., Suda, Y., Fukase, K. (2012). Synthesis and immunomodulatory activities of Helicobacter pylori lipophilic terminus of lipopolysaccharide including lipid A. Carbohydrate Research. 356: 37-43.
92. Moran, A. P., Helander, I. M. and Kosunen, T. U. (1992). Compositional analysis of Helicobacter pylori rough-form lipopolysaccharides. Journal of Bacteriology. 174(4): 1370-1377.
93. Walsh, E. J. and Moran, A. P. (1997). Influence of medium composition on the growth and antigen expression of Helicobacter pylori. Journal of Applied Microbiology. 83(1): 67-75.
94. Anthony, P.M. (2001). Helicobacter pylori: Physiology and Genetics. ASM Press. Chapter 8.
95. Matsuura, M. (2013). Structural modifications of bacterial lipopolysaccharide that facilitate Gram-negative bacteria evasion of host innate immunity. Frontiers in Immunology. 4: 109.
96. Altman, E., Chandan, V., Li, J., Vinogradow, E. (2011). Lipopolysaccharide structures of Helicobacter pylori wild-type strain 26695 and 26695 HP0826: Kan mutant devoid of the O-antigen polysaccharide component. Carbohydrate Research. 346(15): 2437-44.
97. Aspinall, G. O., Monteiro, M. A., Pang, H., Walsh, E. J., and Moran, A. P. (1996). Lipopolysaccharide of the Helicobacter pylori type strain NCTC 11637 (ATCC 43504): structure of the O-antigen chain and core oligosaccharide regions. Biochemistry. 35: 2489-2497.
98. Helander, I. M., Lindner, B., Brade, H., Altmann, K., Lindberg, A. A., Rietschel, E. T., and Zahringer, U. (1988). Chemical structure of the lipopolysaccharide of Haemophilus influenza strain I-69 Rd-/b+. Description of a novel deep-rough chemotype. Eur J Biochem. 177: 483-492.
99. Christina, N., Anna, S., Anthony, P.M., Heidi, A., Lars, E., Staffan, N. (2006). An enzymatic ruler modulates Lewis antigen glycosylation of Helicobacter pylori LPS during persistent infection. Proceedings of the National Academy of Sciences of the United States of America. 103(8): 2863-2868.
100. Moran, A.P. (2007). Lipopolysaccharide in bacterial chronic infection: insights from Helicobacter pylori lipopolysaccharide and lipid A. International Journal of Medical Microbiology. 297: 307-319.
101. Edwards, N. J., Monteiro, M. A., Faller, G., Walsh, E. J., Moran, A. P., Roberts, I. S., et al. (2000). Lewis X structures in the O-antigen side-chain promote adhesion of Helicobacter pylori to the gastric epithelium. Molecular Microbiology. 35(6): 1530-1539
102. Isabelle, H., Marc, R. C., Michelle, M. R., Diane, E.T., Markus, S., Mario, F.F. (2010). Helicobacter pylori lipopolysaccharide is synthesized via a novel pathway with an evolutionary connection to protein N-Glycosylation. Plos Pathogens. 6(3): e1000819.
103. Li, H., Yang, T., Liao, T., Debowski, A.W., Nilsson, H.O., Fulurija, A., Haslam, S.M., Mulloy, B., Dell, A., Stubbs, K.A., Marshall, B.J., Benghezal, M. (2017). The redefinition of Helicobacter pylori lipopolysaccharide O-antigen and core-oligosaccharide domains. Plos Pathogens. 13(3): e1006280.
104. Lehrer, J., Vigeant, K.A., Tatar, L.D., Valvano, M.A. (2007). Functional characterization and membrane topology of Escherichia coli WecA, a sugar- phosphate transferase initiating the biosynthesis of enterobacterial common antigen and O-antigen lipopolysaccharide. Journal of Bacteriology. 189(7): 2618-28.
105. Zhao, G., Wu, B., Li, L., Wang, P.G. (2014). O-antigen polymerase adopts a distributive mechanism for lipopolysaccharide biosynthesis. Applied Microbiology and Biotechnology. 98(9): 4075-81.
106. Ruan, X., Loyola, D.E., Marolda, C.L., Perez-Donoso, J.M., Valvano, M.A. (2012). The WaaL O-antigen lipopolysaccharide ligase has features in common with metal ion-independent inverting glycosyltransferases. Glycobiology. 22(2): 288-99.
107. Chandan, V., et el. (2004). Characterization of a waaF mutant of Helicobacter pylori strain 26695 provides evidence that an extended lipopolysaccharide structure has a limited role in the invasions of gastric cancer cells. Biochem Cell Biol. 85(5): 582-90
108. Altman, E., et al. (2008). Effect of the HP0159 ORF mutation on the lipopolysaccharide structure and colonizing ability of Helicobacter pylori. FEMS Immunol Med Microbiol. 53(2): 204-13.
109. Chang, P. C., Wang, C. J., You, C. K., Kao, M. C. (2011). Effects of a HP0859 (rfaD) knockout mutation on lipopolysaccharide structure of Helicobacter pylori 26695 and the bacterial adhesion on AGS cells. Biochemical and Biophysical Research Communications. 405: 497-502.
110. Han, Y., Han, X., Wang, S., Meng, Q., Zhang, Y., Ding, C., Yu, S. (2014). The WaaL gene is involved in lipopolysaccharide synthesis and plays a role on the bacterial pathogenesis of avian pathogenic Escherichia coli. Veterinary Microbiology. 172(3-4): 486-91.
111. Marolda, C. L., Lahiry, P., Vines, E., Saldias, S., and Valvano, M. A. (2006). Micromethods for the characterization of lipid A-core and O-antigen lipopolysaccharide. Methods in Molecular Biology (Clifton, N.J.). 347:237-252.