Chemistry of non-enzymic browning. II. Reactions between Amino Acids, Organic Acids, and sugars in freeze-dried Apricots and Peaches

Anet, E. F. L. J.; Reynolds, T. M.

doi:10.1071/ch9570182

Cited by 75 publications

(28 citation statements)

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“…However, it is likely that strong selective pressures exist for the evolution and maintenance of the DFG catabolism systems. Amadori compounds, including DFG, form spontaneously in rhizospheres and in rotting plant materials (2). These compounds constitute an excellent source of carbon, nitrogen, and energy, and their utilization could play a role in competition for niche occupancy.…”

Section: Discussionmentioning

confidence: 99%

Convergent Evolution of Amadori Opine Catabolic Systems in Plasmids ofAgrobacterium tumefaciens

et al. 2003

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Deoxyfructosyl glutamine (DFG, referred to elsewhere as dfg) is a naturally occurring Amadori compound found in rotting fruits and vegetables. DFG also is an opine and is found in tumors induced by chrysopine-type strains of Agrobacterium tumefaciens. Such strains catabolize this opine via a pathway coded for by their plasmids. NT1, a derivative of the nopaline-type A. tumefaciens strain C58 lacking pTiC58, can utilize DFG as the sole carbon source. Genes for utilization of DFG were mapped to the 543-kb accessory plasmid pAtC58. Two cosmid clones of pAtC58 allowed UIA5, a plasmid-free derivative of C58, harboring pSa-C that expresses MocC (mannopine [MOP] oxidoreductase that oxidizes MOP to DFG), to grow by using MOP as the sole carbon source. Genetic analysis of subclones indicated that the genes for utilization of DFG are located in a 6.2-kb BglII Opines are produced by crown gall tumor cells, which are induced by pathogenic Agrobacterium spp. (8,56). Genes for the biosynthesis of these compounds are encoded by the T region of Ti (tumor-inducing) or Ri (root-inducing) plasmids, which are present in the plant pathogens. During infection, the T region is transferred to plant cells and stably integrated into the nuclear genome. The genes for production of opines and plant hormones encoded in the integrated DNA are expressed, and opines are released from the transformed plant cells into soil, where they can be utilized by the pathogenic bacterium as carbon and energy sources (8,42,51). The genes for the utilization of the opines by the bacterium also are located on the virulence plasmids, but in segments outside of the T-DNA region. Opines play key roles in the interkingdom interactions between Agrobacterium spp. and infected plants, promoting selective growth of the pathogenic bacterium (15,39,45,54), inducing Ti plasmid conjugal transfer (11, 42), acting as attractants for agrobacterial strains (27), and inhibiting growth of certain agrobacterial strains (16,29).Among the more than 20 known opines, the chrysopine family (5, 7) is produced by tumors induced by A. tumefaciens Chry strains, Ficus strains, and IIBV7 (5, 52). This family of Amadori-type compounds includes N-1-deoxy-D-fructosyl-Lglutamine (DFG, referred to elsewhere as dfg), commonly called santhopine; N-1-deoxy-D-fructosyl-L-glutamate (DFGA, referred to elsewhere as dfga); N-1-deoxy-D-fructosyl-5-oxo-Lproline (DFOP, referred to elsewhere as dfop); and chrysopine, the spiropyranosyl lactone of DFG (5). Chemically, these compounds are closely related to the mannityl opines (Fig. 1). DFG and DFGA are the deoxyfructosyl analogs of mannopine (MOP) and mannopinic acid (MOA), respectively, and chrysopine and DFOP are deoxyfructosyl analogs of agropine (AGR) and agropinic acid, respectively. These similarities suggest a close relatedness in catabolic pathways and also in the genes coding for the enzymes for their catabolism between the two families of opines. In this regard, DFG is an intermediate in the pathway for the catabolism of AGR and MOP coded for b...

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Section: Discussionmentioning

confidence: 99%

Convergent Evolution of Amadori Opine Catabolic Systems in Plasmids ofAgrobacterium tumefaciens

et al. 2003

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“…SOP, the probable substrate of the enzyme encoded by this gene, is a member of the Amadori family of compounds, in which an aldose sugar is coupled with the amino group present in an amino acid or a protein. These compounds can form nonenzymatically by the Maillard reaction and often are present in decaying fruits and vegetables (3,27). SOP, which is one of these primary Amadori compounds, is believed to be the direct precursor of MOP biosynthesis by MOP-and AGRtype tumors (21).…”

Section: Discussionmentioning

confidence: 99%

Ti plasmid-encoded genes responsible for catabolism of the crown gall opine mannopine by Agrobacterium tumefaciens are homologs of the T-region genes responsible for synthesis of this opine by the plant tumor

Kim

Farrand

1996

J Bacteriol

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Agrobacterium tumefaciens NT1 harboring pSaB4, which contains the 14-kb BamHI fragment 4 from the octopine/mannityl opine-type Ti plasmid pTi15955, grew well with agropine (AGR) but slowly with mannopine (MOP) as the sole carbon source. When a second plasmid encoding a dedicated transport system for MOP was introduced, these cells grew well with both AGR and MOP. Transposon insertion mutagenesis and subcloning identified a 5.7-kb region of BamHI fragment 4 that encodes functions required for the degradation of MOP. DNA sequence analysis revealed seven putative genes in this region: mocD (moc for mannityl opine catabolism) and mocE, oriented from right to left, and mocRCBAS, oriented from left to right. Significant identities exist at the nucleotide and derived amino acid sequence levels between these moc genes and the mas genes that are responsible for opine biosynthesis in crown gall tumors. MocD is a homolog of Mas2, the anabolic conjugase encoded by mas2. MocE and MocC are related to the amino half and the carboxyl half, respectively, of Mas1 (MOP reductase), the second enzyme for MOP biosynthesis. These results indicate that the moc and mas genes evolved from a common origin. MocR and MocS are related to each other and to a putative repressor for the AGR degradation system encoded by the rhizogenic plasmid pRiA4. MocB and MocA are homologs of 6-phosphogluconate dehydratase and glucose-6-phosphate dehydrogenase, respectively. Mutations in mocD and mocE, but not mocC, are suppressed by functions encoded by the chromosome or the 450-kb megaplasmid present in many Agrobacterium isolates. We propose that moc genes derived from genes located elsewhere in the bacterial genome and that the tumor-expressed mas genes evolved from the bacterial moc genes.Ti and Ri plasmids of Agrobacterium tumefaciens and Agrobacterium rhizogenes, respectively, carry the genes for the production of unique compounds, called opines, by infected plant cells. These genes, located on the T regions of the Ti and Ri plasmids, are transferred to the plant during infection and are expressed only in the transformed cells of crown gall tumors and hairy roots. Opines produced by the transformed plant are central to the interaction between Agrobacterium spp. and the host plants. These metabolites are utilizable as carbon and energy sources by the pathogenic Agrobacterium sp. that induced the neoplasis.Recent results from two groups demonstrate that the capacity to utilize opines confers on opine-utilizing bacteria a competitive advantage in colonizing plant tissues that produce these substrates (50, 58). Opines also act as signals; certain of these compounds are the specific inducers of the conjugal transfer system of the Ti plasmids. The genes encoding functions required for the utilization of the opine generally also are present on the Ti and Ri plasmids but are outside the T regions (for reviews, see references 18 and 54).Nine families of opines have been identified to date (18). However, any given T region codes for the biosynthesis of only cer...

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“…The most important early reviews related to food were those of Hodge (1953;1967), Anet and Reynolds (1957) and Reynolds (1963;1965). Many other reviews have been written on the chemistry of the Maillard reaction since 1970 (Hodge et aI., 1972;Williams, 1976;Hurrell and Carpenter, 1977;Mabrouk, 1979;Paulsen and Pfiughaupt, 1980;Feather, 1981;Mauron, 1981;Nursten, 1981;Feeney and Whitaker, 1982;Hurrell, 1982;Vernin and Parkanyi, 1982;Namiki and Hayashi, 1983;Feather, 1985;Danehy, 1986;Heath and Reineccius, 1986;Nursten, 1986;Yaylayan and Sporns, 1987;Namiki, 1988;Baltes et ai., 1989;Ledl et aZ., 1989;O'Brien and Morrissey, 1989;Eskin, 1990;Ledl, 1990), and there have been four symposia (Eriksson, 1981;Waller and Feather, 1983;Fujimaki et al, 1986;Finot et al, 1990).…”

Section: The Maillard Reactionmentioning

confidence: 99%

Maillard reactions and meat flavour development

Bailey¹

1994

Flavor of Meat and Meat Products

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Chemistry of non-enzymic browning. II. Reactions between Amino Acids, Organic Acids, and sugars in freeze-dried Apricots and Peaches

Cited by 75 publications

References 0 publications

Convergent Evolution of Amadori Opine Catabolic Systems in Plasmids ofAgrobacterium tumefaciens

Convergent Evolution of Amadori Opine Catabolic Systems in Plasmids ofAgrobacterium tumefaciens

Ti plasmid-encoded genes responsible for catabolism of the crown gall opine mannopine by Agrobacterium tumefaciens are homologs of the T-region genes responsible for synthesis of this opine by the plant tumor

Maillard reactions and meat flavour development

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