U.S. Department of Health and Human Services

Carbohydrates Section

Paul Kovac, Ph.D., Dr. h.c., Chief

Section Staff

Photo of Xiaowei Lu

Xiaowei (Vivian) Lu, Visiting Fellow
Ph.D., Michigan State University, 2012
Thesis: Design and Synthesis of Hyaluronan Pentasaccharide Analogues as Inhibitors of CD44-Hyaluronan Binding
Advisor: Professor Xuefei Huang

B.Sc., Peking University Health Science Center, 2003

Current Project: Synthesis of a library of fragments of  the O-PS of Vibrio Cholera O139 in the form amenable to conjugation. The conformation of the oligosaccharides will be studied by NMR. The binding of the oligosaccharides and of the synthetic hexasaccharide O-PS with homologous antibodies will be explored using microarray technology. We expect the results of such study to provide clues about the minimum structural requirements in the Vibrio cholerae O139 immunogen to elicit protective antibodies.


  • Xiaowei Lu, Xuefei Huang. Design and syntheses of hyaluronan oligosaccharide conjugates as inhibitors of CD44-Hyaluronan binding, Glycoconj J. 2015 May 22. [Epub ahead of print]
  • Xiaowei Lu, Deepak Sail, Pavol Kováč. 4',6'-O-Benzylidene- and 4',6'-O-p-Methoxybenzylidene-α,β cellobiose and Their Hexa-O-β-benzoyl Derivatives, Synthesis 2013; 45(14): 1946-1949
  • Kamat, M.; El-Boubbou, K.; Zhu, D.; Lansdell, T.; Lu, X.; Li, W.; Huang, X. Hyaluronic  Acid Immobilized Magnetic Nanoparticles for Active Targeting and Imaging of Macrophages, Bioconjugate Chem., 2010, 21, 2128–2135
  • Lu, X.; Kamat, M. N.; Huang, L.; Huang, X. Chemical Synthesis of a Hyaluronic Acid Decasaccharide, J. Org. Chem., 2009, 74, 7608-7617 (JOC Featured Article)
  • Miermont, A.; Barnhill, H.; Strable, E.; Lu, X.; Wall, K. A.; Wang, Q.; Finn, M. G.; Huang, X. Cowpea Mosaic Virus Capsid, a Promising Carrier towards the Development of Carbohydrate Based Anti-tumor Vaccines, Chem. Eur. J., 2008, 14, 4939-4947.
  • Huang, L.; Lu, X.; Huang, X. Chemical Syntheses of Hyaluronic Acid Oligosaccharides, in Chemical Glycobiology II: Glycopharmaceuticals and Glycovaccines, ACS symposium series, 2008.
Personal Interests: dancing, cooking, and sewing

Photo of Sameh Soliman

Sameh E. Soliman, Visiting Fellow since 2011
Ph.D., Faculty of Science, Alexandria University and Memorial University of Newfoundland, Canada, 2010
Thesis: Synthesis of glycouronic acid and oligosaccharide derivatives of biological applications.
Advisors: Professor Mina Nashed and Professor Joseph Banoub

M.Sc. and B.Sc. Organic Chemistry, Faculty of Science, Alexandria University, Egypt, 2005 and 1998;
Advisor: Professor Mina Nashed

Current Project: Dr. Soliman’s research is focused on designing the synthesis of the O-specific polysaccharide (O-PS) of Vibrio cholerae O139, which is a phosphorylated hexasaccharide consisting of five different monosaccharides, in a form amenable to conjugation to suitable protein carriers by squaric acid chemistry. At the same time, he is collecting a wide range of synthetic O-PS fragments, which will be used to determine the minimum structural requirements in the Vibrio cholerae O139 antigen which, when transformed into immunogenic conjugates and used as vaccines, elicit protective antibodies

  • “Synthesis of a Conjugation-Ready, Phosphorylated, Tetrasaccharide Fragment of the O-PS of Vibrio cholerae O139”. Sameh E. Soliman and Pavol Kováč;  J. Org. Chem.; 80 (2015), 11227-11232.
  • “Stereoselective syntheses of the conjugation-ready, downstream disaccharide and phosphorylated upstream branched trisaccharide fragments of the O-PS of Vibrio Cholerae O139”. Soliman, E. S., Kováč, P., J. Org. Chem., 80 (2015) 4851-4860.
  • “A convenient synthesis of partially benzylated derivative of β-D-GlcpNAc-(1→3)-β-D-Galp-(1→4)-β-D-Glcp-1-OBn as a versatile building block for sialyl Lewis X antigens”. Sameh E. Soliman, Rafik W. Bassily, Ramadan I. El-Sokkary, and Mina A. Nashed. Lett. Org. Chem., 12 (2015) 413-417.
  • “Synthesis of Methyl 4-azido-2,3-di-O-benzoyl-4-deoxy-α-L-arabino-pyranoside”. Bernhard Muller, Sameh E. Soliman, Markus Blaukopf, Ralph Hollaus, and Paul Kosma; Carbohydrate Chemistry: Proven Synthetic Methods; Kováč, P., Ed.; CRC Press, Taylor & Francis Group: Boca Raton, 2015, pp 193-201.
  • “Practical synthesis of building blocks for oligosaccharides containing the β-D-Galp-(1​→3)-β-D-GlcpNAc motif”. Soliman, E. S., Kováč, P., Synthesis, 46 (2014) 748-751 (PSP#268).
  • “High-energy collision-induced dissociation tandem mass spectrometry of regioisomeric lactose palmitic acid monoesters using matrix-assisted laser desorption/ionization”. Mina R. Narouz, Sameh E. Soliman, Travis D. Fridgen, Mina A. Nashed, and Joseph H. Banoub; Rapid Commun. Mass Spectrom. 28 (2014), 169-177.
  • “Improved synthesis of ethyl (2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-(1→3)-(4,6-O-benzylidene-2-deoxy-1-thio-2-trichloroacetamido-β-D-glucopyranoside)”. Soliman, S., Kováč, P., Carbohydrate Chemistry: Proven Synthetic Methods, Vol. 2, Chapter 25, CRC/Taylor & Francis, Boca Raton, FL, 2014.
  • “Improved synthesis of 6-Azido-6-deoxy- and 6,6'-Diazido-dideoxy-α,α-trehaloses”. Mina R. Narouz, Sameh E. Soliman, Rafik W. Bassily, Ramadan I. El-Sokkary, Adel Z. Nasr, and Mina A. Nashed. SYNLETT, 24 (2013) 2271-2273.
  • “Regioselective synthesis of novel mono-substituted D-lactose fatty acid ester derivatives”. Mina R. Narouz, Sameh E. Soliman, Rafik W. Bassily, Ramadan I. El-Sokkary, Adel Z. Nasr, and Mina A. Nashed. Lett. Org. Chem., 10 (2013) 502-509.
  • “Gas-phase fragmentation study of a novel series of synthetic 2-oxo-2H-benzopyrano[2,3-d]pyrimidine derivatives using electrospray ionization tandem mass spectroscopy measured with a quadrupole orthogonal time-of-flight hybrid instrument”. Hamida Turki, Benoit Genestie, Rachid El Gharbi, Sameh El Boussiry, and Joseph H. Banoub; Rapid Commun. Mass Spectrom. 23 (2009), 267-281.
  • “Facile and Regioselective Synthesis of Parially Benzoylated Sucralose Suitable for Chain Extension at Position O-6”. Sameh E. Soliman and Mina A. Nashed. Bull. Faculty of Science, Alexandria University, 2009.
  • “Regioselective synthesis of a glycomimetic trisaccharide of Sialyl Lewis (sLex)”. Sameh E. Soliman, Rafik W. Bassily, Ramadan I. El-Sokkary, Joseph H. Banoub and Mina A. Nashed. Carbohydr. Res., 344 (2009) 395-399.
  • “Acetylated methyl glucopyranuronate trichloroacetimidate as a glycosyl donor for efficient synthesis of disaccharides”. Sameh E. Soliman, Rafik W. Bassily, Ramadan I. El-Sokkary, and Mina A. Nashed. Carbohydr. Res., 338 (2003) 2337.
Personal Interests: playing table tennis, listening to music, and spending time with his family

Photo of Divya Kushwaha

Divya Kushwaha, Special Volunteer since 2015
Ph.D., Banaras Hindu University, India, 2014
Thesis: Applications of Cu(I) catalyzed Click Reaction in Carbohydrate Chemistry
Advisor: Dr. Vinod K. Tiwari

M.Sc. and B.Sc., Banaras Hindu University, India, 2010 and 2008

Current Project: Synthesis of multivalent glycan antigens in form of clusters and their conjugation to BSA by squaric acid chemistry


  • D. Kushwaha and V. K. Tiwari, Click chemistry inspired synthesis of glycoporphyrin dendrimers, J. Org. Chem., 78, (2013) 8184.
  • D. Kushwaha, P. Dwivedi, S. K. Kuanar, V. K. Tiwari, Click reaction in carbohydrate chemistry: Recent developments and future perspective, Curr. Org. Synth., 10 (2013) 90.
  • D. Kushwaha, R. S. Singh, V. K. Tiwari,  Fluorogenic dual click derived bis-glycoconjugated triazolocoumarins for selective recognition of Cu (II) ion, Tetrahedron Lett., 55 (2014) 532..
  • A. Biswas, R. Pandey, D. Kushwaha, M. Shahid, V. K. Tiwari, A. Misra, D. S. Pandey, Glycosyl based meso-substituted dipyrromethanes as fluorescent probes for Cd2+ /Cu2+ ions, Tetrahedron Lett., 54 (2013) 4193.
  • R. R. Kale, V. Prasad, D. Kushwaha, V. K. Tiwari, Benzotriazole-mediated facile synthesis of novel glycosyl tetrazoles, J. Carbohydr. Chem., 31 (2012) 130.
  • A. Singh, B. B. Mishra, R. R. Kale, D. Kushwaha, V. K. Tiwari A convenient synthesis of novel glycosyl azitidines under mitsunobu reaction conditions, Synth. Commun., 42 (2012) 3598.
  • R. P. Tripathi, P. Dwivedi A. Sharma, D. Kushwaha, V. K Tiwari, Click Chemistry in Glycoscience: New Developments and Strategies,  2013, Wiley & Sons, 293-324.
  • V. Prasad, D. Kushwaha, K. B. Mishra, L. Mishra, V. K. Tiwari, Bentham Publishers, Advances in Organic Synthesis, Volume 4, 2013.
  • D. Kumar, B. B. Mishra, D. Kushwaha, V. K. Tiwari, Chemistry and Pharmacology of Naturally Occurring Bioactive Compounds, CRC press, Taylor and Francis group, USA, 2013
Personal Interests: socializing with friends and family, singing, and cooking

Photo of Peng Xu

Peng Xu, Research Fellow since 2010
Ph.D., Peking Union Medical College, Beijing, China, 2010
Thesis: Synthesis and structure-activity relationship study of macrolide derivatives with novel saccharide substituents
Advisor: Ping-Sheng Lei, Ph.D.

B.Sc., West China University of Medical Sciences, Sichuan, China, 2002

Current Project: Conjugation of amine-containing substances by squaric acid chemistry, and identification of variables that affect the conjugation efficiency. Use of the optimized protocol to make glycoconjugate vaccines for infectious diseases from bacterial antigens.


  • Peng Xu, Edwin D. Stevens, Alfred D. French, Pavol Kovac. Synthesis and molecular structure of the 5-methoxycarbonylpentyl α-glycoside of the upstream, terminal moiety of the O-specific polysaccharide of Vibrio cholerae O1, serotype Inaba. Molecules, 2015, 20, 2892-2902.
  • Louise C. Ivers, Richelle C. Charles, Isabelle J. Hilaire, Leslie M. Mayo-Smith, Jessica E. Teng, J Gregory Jerome, Jenna Rychert, Regina C. LaRocque, Peng Xu, Pavol Kovac, Edward T. Ryan, Firdausi Qadri, Charles P. Almazor, Molly F. Franke, Jason B. Harris. Immunogenicity of the bivalent oral cholera vaccine Shanchol in Haitian adults with HIV infection. J. Infect. Dis., 2015, first published online Feb.26th, 2015.
  • Peng Xu, Sayantan Bhaduri, Pavol Kovac. Isopropyl 2,3,4,6-tetra-O-benzoyl-1-thio-β-D-galactopyranoside, a convenient galactosyl donor, in Carbohydrate chemistry: Proven synthetic methods, Ed. Rene Roy, Sebastien Vidal, Vol. 3. Chapter 29, 227-234, 2015.
  • Peng Xu, Zbigniew Dauter, Pavol Kovac. Synthesis, characterization, and crystal structure of sodium (methyl α-D-mannopyranosid)uronate monohydrate. Synthesis, 2014, 46, 1073-1078.
  • Mohammad Murshid Alam, Megan Kelly Bufano, Peng Xu (co-first authors), Anuj Kalsy, Y. Yu, Y. Wu Freeman, Tania Sultana, Rasheduzzaman Rashu, Ishaan Desai, Grace Eckhoff, Daniel T. Leung, Richelle C. Charles, Regina C. LaRocque, Jason B. Harris, John D. Clements, Stephen B. Calderwood, Firdausi Qadri, W. F. Vann, Pavol Kovac, Edward T. Ryan. Evaluation in mice of a conjugate vaccine for cholera made from Vibrio cholerae O1 (Ogawa) O-specific polysaccharide. PLoS Negl. Trop. Dis, 2014, 8(2), 1-8.
  • Peng Xu, Riccardo Castelli, Pavol Kováč. Synthesis and characterization of tetra-O-propargyl Pentaerythritol. Carbohydrate chemistry: Proven synthetic methods, Vol. 2, 213-216, 2014.
  • Farid Jahouh, Peng Xu, Willie F. Vann, Pavol Kovac, Joseph H. Banoub. Mapping the glycation sites in the neoglycoconjugate from hexasaccharide antigen of Vibrio cholerae, serotype Ogawa and the recombinant tetanus toxin C-fragment carrier. J. Mass. Spectrom., 2013, 48(10), 1083-1090.
  • Daniel T. Leung, Taher Uddin, Peng Xu (co-first authors), Amena Aktar, Russell A. Johnson, Mohammad Arif Rahman, Mohammad Murshid Alam, Meagan Kelly Bufano, Grace Eckhoff, Ying Wu-Freeman, Yanan Yu, Tania Sultana, Farhana Khanam, Amit Saha, Fahima Chowdhury, Ashraf I. Khan, Richelle C. Charles, Regina C. LaRocque, Jason B. Harris, Stephen B. Calderwood, Pavol Kovac, Firdausi Qadri, Edward T. Ryan. Immune responses to the O-specific polysaccharide antigen in children who received a killed oral cholera vaccine compared to responses following natural cholera infection in Bangladesh. Clin. Vaccine Immunol., 2013, 20 (6), 780-788
  • Peng Xu, Pavol Kováč. Observations on the preparation of β-lactose octaacetate. Journal of Carbohydrate Chemistry, 2012, 31, 711-720.
  • Edward T. Ryan, Pavol Kováč, Firdausi Qadri, Peng Xu, Stephen B. Calderwood, Willie F. Vann, Dwight C. Peterson. Conjugating amines. 2012, WO2013009826.
  • Xiaozhuo Chen, Peng Xu, Yanpeng Xu, Lu Liu, Yi Liu, Di Zhu and Pingsheng Lei. Synthesis and antibacterial activity of novel modified 5-O-desosamine ketolides. Bioorg. Med. Chem. Lett. 2012 (22) 7402-7405
  • Russell Johnson, Taher Uddin, Amena Aktar, Md. Mohasin, Mohammad Murshid Alam, Fahima Chowdhury, Jason Harris, Regina LaRocque, Meagan Bufano, Yanan Yu, Ying Wu, Daniel Leung, David Sarracino, Bryan Krastins, Richelle Charles, Peng Xu, Paul Kováč, Stephen Calderwood, Firdausi Qadri, and Edward Ryan. Comparison of immune responses to the O-specific polysaccharide and lipopolysaccharide of Vibrio cholera O1 in Bangladeshi adult patients with cholera. Clin. Vaccine Immunol., 2012, 19 (11), 1712-1721.
  • Xiaozhuo Chen, Peng Xu, Lu Liu and Pingsheng Lei. Synthesis and antibacterial activities of novel ketolides with 11,12-sulfur contained aryl alkyl side chains. Euro. J. Med. Chem. 2011, 46(1), 208-217
  • Peng Xu, Mohammad Murshid Alam, Anuj Kalsy, Richelle C. Charles, Stephen B. Calderwood, Firdausi Qadri, Edward T. Ryan and Pavol Kováč. Simple, direct conjugation of bacterial O-SP–core antigens to proteins: Development of cholera conjugate vaccines. Bioconjugate Chemistry, 2011 20(10), 2179-2185
  • Peng Xu, Lu Liu, Wei He, Yun Li, Jian Liu and Ping-Sheng Lei. Synthesis and antibacterial activity of 11,12-carbamate-3-O-acyl erythromycin derivatives. J. Asian Nat. Prod. Res. 2009, 11(10), 880-897
  • Peng Xu, Lu Liu, Xiao-Zhuo Chen, Yun Li, Jian Liu, Zhi-Ping Jin, Guang-Qiang Wang and Ping-Sheng Lei. Synthesis of novel macrolide derivatives with imidazo[4,5-b]pyridinyl sulfur contained alkyl side chains and their antibacterial activity. Bioorg. Med. Chem. Lett. 2009 (19) 4079-4083
  • Peng Xu, Lu Liu, Zhi-Ping Jin, Guang-Qiang Wang, Jian Liu, Yun Li and Ping-Sheng Lei. Synthesis and antibacterial activity of 4”-O-heteroarylcarbamoyl derivatives of macrolide. Bioorg. Med. Chem. Lett. 2008 (18) 5507-5511
  • Lu Liu, Peng Xu, Liang Zhou and Ping-Sheng Lei. Synthisis of derivatives of imidazo[4,5-b]pyridine: Novel sulfur contained side chains for macrolide antibiotics. Chin. Chem. Lett. 2008 (19) 1-4
  • Peng Xu, Lu Liu, Zhi-Ping Jin and Ping-Sheng Lei. Synthesis and antibacterial activity of derivatives of 6-O-allylic acylides. Bioorg. Med. Chem. Lett. 2007 (17) 3330-3334
  • Peng Xu, Yao Yang, Yang Shi, Lu Liu and Ping-Sheng Lei. Synthesis of derivatives of (9S)-9-hydroxyl-12-methylene erythromycin A and their antibacterial activity in vitro. Acta Pharmaceutica Sinica, 2007, 42(5): 497-501
  • Shu-Jie Hou, Peng Xu, Liang Zhou, De-Quan Yu and Ping-Sheng Lei. Synthesis and antitumor activity of icogenin and its analogue. Bioorg. Med. Chem. Lett. 2006 (16) 2454-2458
  • Ping-Sheng Lei, Peng Xu and Lu Liu. Advance in synthesis of ketolides, a new class of erythromycin derivatives. Acta Academiae Medicinae Sinicae, 2004, 26(4), 467-473
Personal Interests: photography, reading, hiking

View photos of previous associates.