Yang CK

References (5)

Title : Nonclassical protein secretion by Bacillus subtilis in the stationary phase is not due to cell lysis - Yang_2011_J.Bacteriol_193_5607
Author(s) : Yang CK , Ewis HE , Zhang X , Lu CD , Hu HJ , Pan Y , Abdelal AT , Tai PC
Ref : Journal of Bacteriology , 193 :5607 , 2011
Abstract : The carboxylesterase Est55 has been cloned and expressed in Bacillus subtilis strains. Est55, which lacks a classical, cleavable N-terminal signal sequence, was found to be secreted during the stationary phase of growth such that there is more Est55 in the medium than inside the cells. Several cytoplasmic proteins were also secreted in large amounts during late stationary phase, indicating that secretion in B. subtilis is not unique to Est55. These proteins, which all have defined cytoplasmic functions, include GroEL, DnaK, enolase, pyruvate dehydrogenase subunits PdhB and PdhD, and SodA. The release of Est55 and those proteins into the growth medium is not due to gross cell lysis, a conclusion that is supported by several lines of evidence: constant cell density and secretion in the presence of chloramphenicol, constant viability count, the absence of EF-Tu and SecA in the culture medium, and the lack of effect of autolysin-deficient mutants. The shedding of these proteins by membrane vesicles into the medium is minimal. More importantly, we have identified a hydrophobic alpha-helical domain within enolase that contributes to its secretion. Thus, upon the genetic deletion or replacement of a potential membrane-embedding domain, the secretion of plasmid gene-encoded mutant enolase is totally blocked, while the wild-type chromosomal enolase is secreted normally in the same cultures during the stationary phase, indicating differential specificity. We conclude that the secretion of Est55 and several cytoplasmic proteins without signal peptides in B. subtilis is a general phenomenon and is not a consequence of cell lysis or membrane shedding; instead, their secretion is through a process(es) in which protein domain structure plays a contributing factor.
ESTHER : Yang_2011_J.Bacteriol_193_5607
PubMedSearch : Yang_2011_J.Bacteriol_193_5607
PubMedID: 21856851

Title : Isolation, chemical structure, acute toxicity, and some physicochemical properties of territrem C from Aspergillus terreus - Ling_1984_Appl.Environ.Microbiol_47_98
Author(s) : Ling KH , Liou HH , Yang CM , Yang CK
Ref : Applied Environmental Microbiology , 47 :98 , 1984
Abstract : Territrem C, a new tremorgenic mycotoxin (C28H32O9; molecular weight, 512.20) was isolated from the chloroform extract of rice cultures of Aspergillus terreus 23-1, which also produces territrems A and B. Isolation, acute toxicity, and some physicochemical properties of territrem C are discussed in this paper. The spectral and chemical evidence indicated that the structural difference between territrem C and territrem B (C29H34O9) was in their phenyl moieties: a 4-hydroxy-3,5-dimethoxy phenyl group in territrem C and a 3,4,5-trimethoxy phenyl group in territrem B. It was also demonstrated that territrem B was obtained by methylation of territrem C with dimethyl sulfate.
ESTHER : Ling_1984_Appl.Environ.Microbiol_47_98
PubMedSearch : Ling_1984_Appl.Environ.Microbiol_47_98
PubMedID: 6546485

Title : Solvent systems for improved isolation and separation of territrems A and B - Ling_1982_Appl.Environ.Microbiol_44_860
Author(s) : Ling KH , Yang CK , Kuo CA , Kuo MD
Ref : Applied Environmental Microbiology , 44 :860 , 1982
Abstract : Territrems A and B, tremorgenic mycotoxins in the rice culture of Aspergillus terreus, were extracted with hot chloroform. The toxins were cleaned on a silica gel column by direct adsorption-concentration of the extracts followed by desorption with chloroform-acetone (9:1, vol/vol). Crude toxin mixtures were separated by silica gel column chromatography and eluted with benzene-ethyl acetate (65:35, vol/vol). The method gave 112 mg of territrem A, 379 mg of territrem B, and 80 mg of their mixture from 4 kg of rice per batch. The criteria of extraction, cleanup, and separation are provided.
ESTHER : Ling_1982_Appl.Environ.Microbiol_44_860
PubMedSearch : Ling_1982_Appl.Environ.Microbiol_44_860
PubMedID: 7149718

Title : Territrems, tremorgenic mycotoxins of Aspergillus terreus - Ling_1979_Appl.Environ.Microbiol_37_355
Author(s) : Ling KH , Yang CK , Peng FT
Ref : Applied Environmental Microbiology , 37 :355 , 1979
Abstract : The tremorgenic mycotoxins isolated from Aspergillus terreus were given the trivial names territrem A and B instead of their previous designations of C1 and C2 respectively. High-resolution mass spectral data suggested the molecular formula of territrem A to be C28H30O9 and that of territrem B,C29H34O9. They were partially characterized by ultraviolet, infrared, proton magnetic resonance, and mass spectroscopy. The spectroscopic evidence indicated that their chemical structures were very similar. The procedures of purification were also revised for the complete separation of these two chemically related compounds.
ESTHER : Ling_1979_Appl.Environ.Microbiol_37_355
PubMedSearch : Ling_1979_Appl.Environ.Microbiol_37_355
PubMedID: 453815

Title : Differentiation of aflatoxins from territrems - Ling_1979_Appl.Environ.Microbiol_37_358
Author(s) : Ling KH , Yang CK , Huang HC
Ref : Applied Environmental Microbiology , 37 :358 , 1979
Abstract : Three methods were adopted for differentiation of aflatoxins B1 and B2 from territrems A and B. They were as follows. (i) Then-layer chromatography coupled with chemical confirmation. A significant decrease in the Rf value of trifluoroacetic acid-treated aflatoxin B1 developed in chloroform-acetone (85:15, vol/vol) was satisfactory in differentiating this toxin from the other three. (ii) High-pressure liquid chromatography monitored synchronously at two wavelengths, 365 and 335 nm. The ratio derived from this double-wavelengh detection could serve as an indicator of the presence of each toxin. (iii) Velasco's flurotoxin meter method, which is used for the determination of aflatoxins within the range of 0 to 50 ng/ml, was not significantly affected by territrems even when they were present in quantities at the microgram-per-milliliter level.
ESTHER : Ling_1979_Appl.Environ.Microbiol_37_358
PubMedSearch : Ling_1979_Appl.Environ.Microbiol_37_358
PubMedID: 453816