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Featured researches published by Tim A. Smitka.


Tetrahedron | 1996

A90720A, a serine protease inhibitor isolated from a terrestrial blue-green alga Microchaete loktakensis

Rosanne Bonjouklian; Tim A. Smitka; Ann H. Hunt; John L. Occolowitz; Thomas J. Perun; Lawrence E. Doolin; Stephanie Stevenson; Lisa Knauss; Ranmali Wijayaratne; Stanley Szewczyk; Gregory M. L. Patterson

Abstract The isolation and structure elucidation of A90720A, 1 , a cyclic depsipeptide from the terrestrial blue-green alga Microchaete loktakensis is described. 1 was isolated on the basis of its thrombin inhibitory activity and its structure was determined using spectral methods and amino acid analysis. The absolute configurations of the constituent amino acids were found to be as follows: the nucleus contains L -threonine, L -arginine, L -3-amino-6-hydroxy-2-piperidone (Ahp, i.e., glutamic acid-γ-car☐aldehyde), L -leucine, L -N-methyl-tyrosine and L -valine. The side chain off the L -threonine amino group contains D -leucine, followed by a 3-O-sulfated R -glycerate moiety.


Biotechnology Progress | 2013

Fermentanomics informed amino acid supplementation of an antibody producing mammalian cell culture

Erik K. Read; Scott A. Bradley; Tim A. Smitka; Cyrus Agarabi; Scott Lute; Kurt Brorson

Fermentanomics, or a global understanding of a culture state on the molecular level empowered by advanced techniques like NMR, was employed to show that a model hybridoma culture supplied with glutamine and glucose depletes aspartate, cysteine, methionine, tryptophan, and tyrosine during antibody production. Supplementation with these amino acids prevents depletion and improves culture performance. Furthermore, no significant changes were observed in the distribution of glycans attached to the IgG3 in cultures supplemented with specific amino acids, arguing that this strategy can be implemented without fear of impact on important product quality attributes. In summary, a targeted strategy of quantifying media components and designing a supplementation strategy can improve bioprocess cell cultures when enpowered by fermentanomics tools. Published 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:745–753, 2013


Phytochemistry | 1989

Hapalonamides and other oxidized hapalindoles from Hapalosiphon fontinalis

Richard E. Moore; Xu-qiang G. Yang; Gregory M. L. Patterson; Rosanne Bonjouklian; Tim A. Smitka

Abstract Dechlorofontonamide, anhydrohapaloxindoles B and M, and hapalonamides G, H, and V have been isolated as minor indole alkaloids from a cultured strain of the terrestrial blue-green alga Hapalosiphon fontinalis .


Journal of the American Chemical Society | 1994

Welwitindolinones, Unusual Alkaloids from the Blue-Green Algae Hapalosiphon welwitschii and Westiella intricata. Relationship to Fischerindoles and Hapalinodoles

Klemens Stratmann; Richard E. Moore; Rosanne Bonjouklian; Jack B. Deeter; Gregory M. L. Patterson; Stacey Shaffer; Charles D. Smith; Tim A. Smitka


Journal of Organic Chemistry | 1987

Hapalindoles, antibacterial and antimycotic alkaloids from the cyanophyte Hapalosiphon fontinalis

Richard E. Moore; Chad Cheuk; Xu Qiang G. Yang; Gregory M. L. Patterson; Rosanne Bonjouklian; Tim A. Smitka; Jon S. Mynderse; Ron S. Foster; Noel D. Jones


Journal of Organic Chemistry | 1992

Ambiguine isonitriles, fungicidal hapalindole-type alkaloids from three genera of blue-green algae belonging to the Stigonemataceae

Tim A. Smitka; Rosanne Bonjouklian; Larry E. Doolin; Noel D. Jones; Jack B. Deeter; Wesley Y. Yoshida; Michèle R. Prinsep; Richard E. Moore; Gregory M. L. Patterson


Journal of the American Chemical Society | 2010

Fermentanomics: Monitoring Mammalian Cell Cultures with NMR Spectroscopy

Scott A. Bradley; Anli Ouyang; Jennifer Purdie; Tim A. Smitka; Tongtong Wang; Andreas Kaerner


The Journal of Antibiotics | 1988

A83586C, A NEW DEPSIPEPTIDE ANTIBIOTIC

Tim A. Smitka; Jack B. Deeter; Ann H. Hunt; Frederick P. Mertz; Robert M. Ellis; Laverne Dwaine Boeck; Raymond C. Yao


Chemistry & Biology | 1994

Atomic structure of the trypsin-A90720A complex: a unified approach to structure and function

Angela Y. Lee; Tim A. Smitka; Rosanne Bonjouklian; Jon Clardy


The Journal of Antibiotics | 1992

A83016A, a new kinamycin type antibiotic.

Tim A. Smitka; Rosanne Bonjouklian; Thomas J. Perun; Ann H. Hunt; Ronald S. Foster; Jon S. Mynderse; Raymond C. Yao

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Jon S. Mynderse

Scripps Institution of Oceanography

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