Neng-Jen Shih

Lambda Instruments (United States)

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Karen A. McDonald

University of California, Davis

Ronald G. Labbé

University of Massachusetts Amherst

R.G. Labbé

University of Massachusetts Amherst

Alan P. Jackman

United States Geological Survey

Tomás Girbés

Universidad de Valladolid

Rui Pei

Thermo Fisher Scientific (United States)

Daniel Coutts

Suez (Canada)

Paul I. Terasaki

Terasaki Foundation

Jar-How Lee

Terasaki Foundation

Mike Y. Chen

Tulane University

Cooperative Institutions

University of California, Davis

Lambda Instruments (United States)

University of Massachusetts Amherst

University of Washington

Universidad de Valladolid

Thermo Fisher Scientific (United States)

Terasaki Foundation

University of California, Los Angeles

University of Southern California

Southwestern University

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Characterization and distribution of amylases during vegetative cell growth and sporulation ofClostridium perfringens

Canadian Journal of Microbiology (1996)

Neng-Jen Shih Ronald G. Labbé

Clostridium perfringens produced eight extracellular and two intracellular amylolytic activities when examined by zymograms following polyacrylamide gel electrophoresis under native conditions. The major intracellular amylase was isolated from vegetative cells of C. perfringens. It possessed an estimated molecular mass of 112 kDa. Sulfhydryl and phenol functional groups were essential to its activity. The amylase was endo-acting on starch and also hydrolyzed pullulan. Polyclonal antisera against a purified extracellular amylase did not cross-react with intracellular amylase and the two amylases were biochemically different. The distribution of extracellular amylolytic activities of sporulating cells was different from that of vegetative cells, whereas the distribution of intracellular amylolytic activities remained identical. A significant increase of a particular amylase (A8) occurred in the extracellular fluid during sporulation compared with that during vegetative growth. Regulation of the excretion of amylase(s) may be sporulation and enterotoxingenicity related.Key words: Clostridium perfringens, amylase, sporulation.

Clostridium perfringens

10.1139/m96-086

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Citations (8)

Sporulation-Promoting Ability ofClostridium perfringens Culture Fluids

Neng-Jen Shih

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Purification and characterization of chitinases from transformed callus suspension cultures of Trichosanthes kirilowii Maxim.

Journal of Fermentation and Bioengineering (1997)

Neng-Jen Shih Karen A. McDonald

10.1016/s0922-338x(97)82782-1

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Kinetics of Growth and Ribosome-Inactivating Protein Production from Trichosanthes kirilowii Plant Cell Cultures in a 5-L Bioreactor

Biotechnology Progress (1997)

Michael R. Stoner Craig Humphrey Daniel Coutts Neng-Jen Shih Karen A. McDonald

Ribosome-inactivating proteins, named for their ability to inhibit protein translation in cell-free systems, are an important class of natural plant defense proteins with potential human therapeutic and agricultural applications. The kinetics of growth, nutrient consumption, and extracellular protein translation inhibitory activity are presented for Trichosanthes kirilowii plant cell suspensions in 5-L bioreactors at two agitation rates (50 and 100 rpm) . The cultures had a 7–9.5 day lag phase followed by exponential growth with a doubling time of less than 2 days. Biomass concentrations reached levels of approximately 19 g (dry weight) /L. Protein translation inhibitory activity was observed in the culture broths during the exponential growth phase and reached levels of approximately 50–60 units. No detrimental effects of agitation were observed at 100 rpm. These studies demonstrate the potential for plant cell culture production of ribosome-inactivating proteins in bioreactor systems.

10.1021/bp970090k

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Isolation, characterization and regulation of amylases from {\it Clostridium perfringens/}

Neng-Jen Shih

Isolation

Clostridium perfringens

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Citations (3)

Effect of glucose on sporulation and extracellular amylase production byClostridium perfringens type A in a defined medium

Current Microbiology (1994)

Neng-Jen Shih Ronald G. Labbé

10.1007/bf01570758

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Citations (15)

Purification and characterization of an extracellular alpha-amylase from Clostridium perfringens type A

Applied and Environmental Microbiology (1995)

Neng-Jen Shih R.G. Labbé

An alpha-amylase (EC 3.2.1.1) secreted by Clostridium perfringens NCTC 8679 type A was purified to homogeneity and characterized. It was isolated from concentrated cell-free culture medium by ion-exchange and gel permeation chromatography. The enzyme exhibited maximal activity at pH 6.5 and 30 degrees C without the presence of calcium. The pI of the enzyme was 4.75. The estimated molecular weight of the purified enzyme was 76 kDa. The purified enzyme was inactivated between 35 and 40 degrees C, which increased to between 45 and 50 degrees C in the presence of calcium (5 mM). The purified enzyme produced a mixture of oligosaccharides as major end products of starch hydrolysis, indicating alpha-amylase activity.

Clostridium perfringens

Alpha-amylase

Gel permeation chromatography

10.1128/aem.61.5.1776-1779.1995

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Citations (31)

Short Communication

Biological Chemistry (1998)

Neng-Jen Shih Karen A. McDonald Tomás Girbés Rosario Iglesias A J Kohlhoff

Two type 1 RIPs, designated as MOR-I and MOR-II, have been isolated from Marah oreganus (manroot) seed extract.They are similar but not identical to trichosanthin, a type 1 RIP in the same family.MOR-I and MOR-II are monomeric proteins with molecular weights of 27989.0 and 27632.8respectively and have pi values greater than 8.8.MOR-I and MOR-II inhibit cell-free protein synthesis with ICsoS of 0.063 and 0.071 nM, respectively, and are relatively stable with respect to temperature and pH variations.They share a conserved N-terminal amino acid sequence (D-SF-LS) and cross-react with goat anti-trichosanthin polyclonal serum.

Trichosanthin

Polyclonal antibodies

Sequence (biology)

10.1515/bchm.1998.379.6.721

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Single human leukocyte antigen flow cytometry beads for accurate identification of human leukocyte antigen antibody specificities

Transplantation (2003)

Rui Pei Jar-How Lee Neng-Jen Shih Mike Y. Chen Paul I. Terasaki

It is difficult to assign antibody specificity for highly sensitized patients using a cell panel with multiple antigens per reaction. We describe here a single antigen bead panel for accurate identification of human leukocyte antigen (HLA) antibody specificities by flow cytometry.A total of 110 single recombinant HLAs, including 34 A locus alleles, 57 B locus alleles, and 19 C locus alleles, were produced by a mammalian expression system. These single antigens were coated onto eight different colored microbeads, which were mixed together in one tube for simultaneous detection of HLA antibodies against eight different antigens per flow cytometry test.Single HLA reacted specifically with the serologically defined monoclonal antibodies. The single antigen panel provided higher resolution than the regular cell panel for antibody detection by uncovering the masked specificities. Single antigens also provided higher sensitivity than the multiple antigens coated onto beads for HLA antibody detection as demonstrated by serum dilution studies. In 10 sera from patients who had rejected a kidney transplant, single antigen beads identified antibodies to 31 of 35 antigens that were mismatched in the donor. Most important, none of the reactions were against antigens present in the recipient.An accurate and sensitive HLA antibody detection method is described using flow cytometry beads coated with single HLAs produced by recombinant technology. The single antigen beads should be useful in predicting negative crossmatch in highly sensitized organ recipients and highly sensitized patients requiring platelets.

Panel reactive antibody

10.1097/00007890-200301150-00008

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Citations (396)

Sporulation-promoting ability of Clostridium perfringens culture fluids

Applied and Environmental Microbiology (1996)

Neng-Jen Shih R.G. Labbé

The culture supernatant fluids (CSFs) of 12 strains of Clostridium perfringens types A, B, C, and D stimulated sporulation of test strains NCTC 8238 and NCTC 8449 of this organism. The sporulation-promoting ability was present in vegetative and sporulating CSFs of both enterotoxin-positive (Ent+) and Ent- strains. The sporulation factor possessed a molecular weight between 1,000 and 5,000 and was heat and acid stable. This study suggests a potential role for Ent- strains in food-borne disease outbreaks caused by Ent+ strains of C. perfringens type A.

Clostridium perfringens

10.1128/aem.62.4.1441-1443.1996

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Citations (14)