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1.
F. Quondamatteo Thomas Gerhard Schulz Nathalie Bunzel Ernst Hallier Rainer Herken 《Histochemistry and cell biology》1998,110(4):417-423
Glutathione S-transferase-mediated metabolism of exogenous compounds usually leads to detoxification, but there are some
exceptions. For example, glutathione S-transferase-T1 (GSTT1) can also generate genotoxic metabolites. Studies on the biology
of GSTT1 are limited by the lack of specific antibodies recognizing GSTT1 in animal tissues. We localized GSTT1 immunohistochemically
in mouse kidney, liver, and lung using a novel antibody targeted against the C-terminus of rat GSTT1 (rGSTT1). The antibody
was characterized using immunoblot and shown to specifically recognize rGSTT1 and mouse GSTT1, but not human GSTT1. In kidney,
GSTT1 staining was detected only in collecting duct epithelium. In liver, pericentral hepatocytes showed cytoplasmic and nuclear
staining. Nuclear staining was also observed in several other hepatocytes without relation to liver zonation. Nuclei and supranuclear
cytoplasm of bile duct epithelium and endothelium of interlobular arterioles also reacted strongly. In lung, staining was
observed in bronchiolar epithelium and in surrounding muscle cells. Type II pneumocytes and endothelial cells of intrapulmonary
capillaries also showed strong positive staining. This report describes the first immunohistochemical localization of GSTT1
in mammalian tissues. The reported location of GSTT1 is consistent with its known metabolic activity toward compounds such
as dichloromethane and their metabolism into genotoxic products.
Accepted: 11 May 1998 相似文献
2.
Sebastian T. Soukup Britta Spanier Gregor Grünz Diana Bunzel Hannelore Daniel Sabine E. Kulling 《PloS one》2012,7(10)
Background
Caenorhabditis elegans (C. elegans) has become a widely used model to explore the effect of food constituents on health as well as on life-span extension. The results imply that besides essential nutrients several flavonoids are able to impact the aging process. What is less investigated is the bioavailability and biotransformation of these compounds in C. elegans. In the present study, we focused on the soy isoflavone genistein and its metabolism in the nematode as a basis for assessing whether this model system mimics the mammalian condition.Principal Findings
C. elegans was exposed to 100 µM genistein for 48 hours. The worm homogenate was extracted and analyzed by liquid chromatography (LC). 11 metabolites of genistein were detected and characterized using LC electrospray ionization mass spectrometry. All genistein metabolites formed by C. elegans were found to be sugar conjugates, primarily genistein-O-glucosides. The dominant metabolite was identified as genistein-7-O-phosphoglucoside. Further interesting metabolites include two genistein-di-O-glycosides, a genistein-O-disaccharide as well as a genistein-O-phosphodisaccharide.Conclusions/Significance
Our study provides evidence for a novel biotransformation pathway in C. elegans leading to conjugative metabolites which are not known for mammals. The metabolism of genistein in mammals and in C. elegans differs widely which may greatly impact the bioactivity. These differences need to be appropriately taken into consideration when C. elegans is used as a model to assess possible health or aging effects. 相似文献3.
In vitro evidence that transcription-induced stress causes nucleosome dissolution and regeneration 总被引:3,自引:0,他引:3
P Pfaffle V Gerlach L Bunzel V Jackson 《The Journal of biological chemistry》1990,265(28):16830-16840
4.
Margret Bunzel und Joachim Drüke 《Journal of Ornithology》1986,127(3):337-338
Summary On 24. and 26.7. 1986 a ringed first-year male kingfisher was observed carrying fish into a burrow containing nestlings 22–24 days old. The first-year bird had hatched at a breeding site 5.5 km away from the place where it helped feed the nestlings and left its own natal nest on 11.6. 1984. The first-year kingfisher's parents were not the adult birds whose nestlings the young male was feeding. 相似文献
5.
Raorane Manish L. Manz Christina Hildebrandt Sarah Mielke Marion Thieme Marc Keller Judith Bunzel Mirko Nick Peter 《Protoplasma》2023,260(2):349-369
Protoplasma - Since the discovery of the anticancer drugs vinblastine and vincristine, Catharanthus roseus has been intensively studied for biosynthesis of several terpene indole alkaloids (TIAs).... 相似文献
6.
Isolation and structural identification of complex feruloylated heteroxylan side-chains from maize bran 总被引:1,自引:0,他引:1
Three complex heteroxylan side-chains acylated with ferulate and one arabinosyl ester of p-coumaric acid have been isolated from maize bran insoluble fibre after acidic hydrolysis and fractionation by gel permeation chromatography and semi-preparative RP-HPLC. The complete structural elucidation of all isolated compounds was achieved by 1D/2D NMR spectroscopy and HPLC-MS in combination with methylation analysis. The absolute configuration of the carbohydrate constituents was determined by chiral GC after acidic hydrolysis and trifluoroacetylation. The identified feruloylated tetrasaccharides alpha-d-xylopyranosyl-(1-->3)-alpha-l-galactopyranosyl-(1-->2)-beta-d-xylopyranosyl-(1-->2)-5-O-trans-feruloyl-l-arabinofuranose (FAXGX) and alpha-d-galactopyranosyl-(1-->3)-alpha-l-galactopyranosyl-(1-->2)-beta-d-xylopyranosyl-(1-->2)-5-O-trans-feruloyl-l-arabinofuranose (FAXGG) are the most complex heteroxylan side-chains from maize bran that have been isolated to date. The isolated trisaccharide alpha-l-galactopyranosyl-(1-->2)-beta-d-xylopyranosyl-(1-->2)-5-O-trans-feruloyl-l-arabinofuranose (FAXG) contributes to the complexity of heteroxylan side-chains from maize bran and 5-O-trans-p-coumaroyl-l-arabinofuranose represents the first p-coumaroylated heteroxylan side-chain isolated from cereal grains. Complex feruloylated heteroxylan side-chains are possibly, like ferulate cross-linking of the heteroxylans and binding of heteroxylans to lignin, a factor contributing to limited enzymatic degradation of fibre. 相似文献
7.
Wang BC Adams MW Dailey H DeLucas L Luo M Rose J Bunzel R Dailey T Habel J Horanyi P Jenney FE Kataeva I Lee HS Li S Li T Lin D Liu ZJ Luan CH Mayer M Nagy L Newton MG Ng J Poole FL Shah A Shah C Sugar FJ Xu H 《Journal of structural and functional genomics》2005,6(2-3):233-243
Using a high degree of automation, the Southeast Collaboratory for Structural Genomics (SECSG) has developed high throughput
pipelines for protein production, and crystallization using a two-tiered approach. Primary, or tier-1, protein production
focuses on producing proteins for members of large Pfam families that lack a representative structure in the Protein Data
Bank. Target genomes are Pyrococcus furiosus and Caenorhabditis elegans. Selected human proteins are also under study. Tier-2 protein production, or target rescue, focuses on those tier-1 proteins,
which either fail to crystallize or give poorly diffracting crystals. This two tier approach is more efficient since it allows
the primary protein production groups to focus on the production of new targets while the tier-2 efforts focus on providing
additional sample for further studies and modified protein for structure determination. Both efforts feed the SECSG high throughput
crystallization pipeline, which is capable of screening over 40 proteins per week. Details of the various pipelines in use
by the SECSG for protein production and crystallization, as well as some examples of target rescue are described. 相似文献
8.
Mirko Bunzel 《Phytochemistry Reviews》2010,9(1):47-64
Hydroxycinnamates such as ferulic acid, sinapic acid and p-coumaric acid ester-linked to plant cell wall polymers may act as cross-links between polysaccharides to each other, but
also to proteins and lignin. Although sinapates and p-coumarates also form cell wall cross-links by the formation of radically or photochemically formed dimers, ferulate derivatives
are the quantitatively most important cross-links in the plant cell wall. While the first radically generated ferulate dimer
was already identified almost 40 years ago, the spectrum of known ferulate dimers was considerably broadened within the last
15 years. Higher ferulate oligomers were generated in model systems, but also isolated from plant materials. Different model
systems using either free hydroxycinnamic acids or their esters are reviewed, highlighting a discussion of the relevance of
these models for the plant cell wall. The first ferulate trimer from plant material was discovered in 2003 and seven dehydrotrimers
of ferulic acid were isolated from maize bran since. Some of these trimers were also identified in other plant materials such
as wheat and rye grains, corn stover, sugar beet and asparagus. Formation mechanisms of ferulate trimers and implications
for the plant cell wall are discussed. Ferulate tetramers are the highest oligomers isolated from plant materials so far.
These compounds can theoretically cross-link up to four polysaccharide chains, assuming all cross-links are formed intermolecularly.
Formation of intramolecular versus intermolecular polysaccharide cross-links is a key question to be answered in the future
if we want to judge properly the importance of hydroxycinnamate cross-links in the plant cell wall. 相似文献
9.
Diana Linke Rene Matthes Manfred Nimtz Holger Zorn Mirko Bunzel Ralf G. Berger 《Applied microbiology and biotechnology》2013,97(16):7241-7251
Investigating the secretion of esterases by the basidiomycetous fungus Pleurotus sapidus in a Tween 80-rich nutrient medium, an enzyme was discovered that hydrolyzed the ester bond of feruloylated saccharides. The enzyme was purified by ion exchange and size exclusion chromatography. Polyacrylamide gel electrophoresis analysis showed a monomeric protein of about 55 kDa. The complete coding sequence with an open reading frame of 1,665 bp encoded a protein (Est1) consisting of 554 amino acids. The enzyme showed no significant homology to any published feruloyl esterase sequences, but possessed putative conserved domains of the lipase/esterase superfamily. Substrate specificity studies classified the new enzyme as type-A feruloyl esterase, hydrolyzing methyl ferulate, methyl sinapate, and methyl p-coumarate but no methyl caffeate. The enzyme had a pH optimum of 6 and a temperature optimum at 50 °C. Ferulic acid was efficiently released from ferulated saccharides, and the feruloyl esterase exhibited moderate stability in biphasic systems (50 % toluene or tert-butylmethyl ether). 相似文献
10.
Peroxidase-dependent cross-linking reactions of p-hydroxycinnamates in plant cell walls 总被引:1,自引:0,他引:1
Ralph John Bunzel Mirko Marita Jane M. Hatfield Ronald D. Lu Fachuang Kim Hoon Schatz Paul F. Grabber John H. Steinhart Hans 《Phytochemistry Reviews》2004,3(1-2):79-96
Peroxidases are heavily implicated in plant cell wall cross-linking reactions, altering the properties of the wall and impacting its utilization. Polysaccharide-polysaccharide cross-linking in grasses is achieved by dehydrodimerization of hydroxycinnamate-polysaccharide esters; a complex array of hydroxycinnamic acid dehydrodimers are released by saponification. Ferulates are the major cross-linking agents, but sinapate-ferulate cross-products have been discovered implicating sinapates in a similar role. New dehydrodimers have been authenticated, expanding our knowledge of the chemistry, role, and extent of cross-linking reactions. Ferulate dehydrotrimers have been discovered; whether these trimers truly cross-link three independent polysaccharide chains or only two remains to be determined. Hydroxycinnamates and their dehydrodimers also undergo radical coupling reactions with lignin monomers and possibly oligomers, resulting in lignin-polysaccharide cross-linking in the wall. Both polysaccharide-polysaccharide and lignin-polysaccharide cross-links inhibit the enzymatic hydrolysis of cell walls. The cross-linking process has particular relevance to plant physiology, human and animal nutrition and health, and food technology. Abbreviations: CW – cell wall; DFA – dehydrodiferulic acid (or dehydrodiferulate in context); DSA – dehydrodisinapic acid; TFA – dehydrotriferulic acid; SA – sinapic acid (1 S); TA – thomasidioic acid (5C3 SS); IDF – insoluble dietary fiber; SDF – soluble dietary fiber; GC-MS – gas chromatography-mass spectrometry; NMR – nuclear magnetic resonance (spectroscopy). 相似文献