Dissolution of Xylose Metabolism in
            <i>Lactococcus lactis</i>

Erlandson, Karn; Park, Joo-Heon; Wissam,; Khal, El; Kao, Hsin-Hsin; Basaran, Pervin; Brydges, Susannah; Batt, Carl A.

doi:10.1128/aem.66.9.3974-3980.2000

Cited by 45 publications

(34 citation statements)

References 48 publications

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“…Another explanation for this finding is that L. lactis KF147 XylR is different from XylR transcriptional regulators found in other Firmicutes (62). L. lactis KF147 XylR is a member of the AraC family of transcriptional regulators, whereas XylR proteins from related bacteria are classified as ROK (repressor, open reading frame, kinase) family regulators (62,63). In E. coli, expression of the araBAD operon is highly induced upon exposure to arabinose through a "light switch"-type mechanism of AraC (64).…”

Section: Discussionmentioning

confidence: 87%

Lactococcus lactis Metabolism and Gene Expression during Growth on Plant Tissues

Golomb

Marco

2014

J. Bacteriol.

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Lactic acid bacteria have been isolated from living, harvested, and fermented plant materials; however, the adaptations these bacteria possess for growth on plant tissues are largely unknown. In this study, we investigated plant habitat-specific traits of Lactococcus lactis during growth in an Arabidopsis thaliana leaf tissue lysate (ATL). L. lactis KF147, a strain originally isolated from plants, exhibited a higher growth rate and reached 7.9-fold-greater cell densities during growth in ATL than the dairy-associated strain L. lactis IL1403. Transcriptome profiling (RNA-seq) of KF147 identified 853 induced and 264 repressed genes during growth in ATL compared to that in GM17 laboratory culture medium. Genes induced in ATL included those involved in the arginine deiminase pathway and a total of 140 carbohydrate transport and metabolism genes, many of which are involved in xylose, arabinose, cellobiose, and hemicellulose metabolism. The induction of those genes corresponded with L. lactis KF147 nutrient consumption and production of metabolic end products in ATL as measured by gas chromatography-time of flight mass spectrometry (GC-TOF/MS) untargeted metabolomic profiling. To assess the importance of specific plant-inducible genes for L. lactis growth in ATL, xylose metabolism was targeted for gene knockout mutagenesis. Wild-type L. lactis strain KF147 but not an xylA deletion mutant was able to grow using xylose as the sole carbon source. However, both strains grew to similarly high levels in ATL, indicating redundancy in L. lactis carbohydrate metabolism on plant tissues. These findings show that certain strains of L. lactis are well adapted for growth on plants and possess specific traits relevant for plant-based food, fuel, and feed fermentations. L actic acid bacteria (LAB) found on plants are essential for the production of a wide variety of plant-derived fermented foods with desirable organoleptic properties, improved nutritional attributes, and extended shelf life (1). LAB are a diverse group of bacterial species in the Firmicutes phylum that are characterized by the production of lactic acid as the main end product of carbohydrate metabolism. Some of the most commonly recognized genera among the LAB include Lactococcus, Lactobacillus, Leuconostoc, Pediococcus, and Oenococcus. LAB-fermented plantbased food products include sauerkraut, sourdough, and olives, as well as diverse foods unique to different ethnic groups (e.g., pulque, nukadoko, or gundruk [2,3]). LAB are responsible for the conversion of plant tissues such as alfalfa into silage for animal feed with enhanced nutritional content and stability (4). LAB are also used to ferment plant-based substrates into industrial-grade lactic acid for the manufacture of polylactide bioplastics (5). Conversely, LAB are frequent contaminants of bioethanol fermentations (6).In contrast to commercial dairy fermentations that utilize starter cultures, initiation of plant-based fermentations typically relies on the LAB that are located on or associated with plant tis...

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Section: Discussionmentioning

confidence: 87%

Lactococcus lactis Metabolism and Gene Expression during Growth on Plant Tissues

Golomb

Marco

2014

J. Bacteriol.

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“…1). An open reading frame with homology to the gene for xylose kinase (XylB) was located downstream of xylA in the same orientation, indicating that the genes for xylose utilization by L. reuteri 100-23 were organized in an operon, as described for several other gram-positive bacteria (9). Sequence analysis of the promoter region of met revealed that gene expression is likely to be transcriptionally regulated by the T box mechanism (12).…”

Section: Resultsmentioning

confidence: 94%

A High-Molecular-Mass Surface Protein (Lsp) and Methionine Sulfoxide Reductase B (MsrB) Contribute to the Ecological Performance of Lactobacillus reuteri in the Murine Gut

Walter

Chagnaud

Tannock

et al. 2005

Appl Environ Microbiol

115

125

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Members of the genus Lactobacillus are common inhabitants of the gut, yet little is known about the traits that contribute to their ecological performance in gastrointestinal ecosystems. Lactobacillus reuteri 100-23 persists in the gut of the reconstituted Lactobacillus-free mouse after a single oral inoculation. Recently, three genes of this strain that were specifically induced (in vivo induced) in the murine gut were identified (38). We report here the detection of a gene of L. reuteri 100-23 that encodes a high-molecular-mass surface protein (Lsp) that shows homology to proteins involved in the adherence of other bacteria to epithelial cells and in biofilm formation. The three in vivo-induced genes and lsp of L. reuteri 100-23 were inactivated by insertional mutagenesis in order to study their biological importance in the murine gastrointestinal tract. Competition experiments showed that mutation of lsp and a gene encoding methionine sulfoxide reductase (MsrB) reduced ecological performance. Mutation of lsp impaired the adherence of the bacteria to the epithelium of the mouse forestomach and altered colonization dynamics. Homologues of lsp and msrB are present in the genomes of several strains of Lactobacillus and may play an important role in the maintenance of these bacteria in gut ecosystems.The guts of mammals are colonized by a complex collection of microorganisms (the gut microbiota) that influence biochemical, physiological, immunological, and nonspecific disease resistance characteristics of the host (10). The bacterial composition of this ecosystem has been shown to be remarkably stable over time (43). Members of the gut microbiota have presumably coevolved with their host species and must possess traits that enable them to establish and maintain themselves in a lotic (flowing) and competitive environment. On the other hand, there are microbes present in the gastrointestinal tract that have a transient existence (allochthonous components), and this situation raises questions about what factors distinguish resident members of the microbiota from allochthonous members (27).Lactobacillus reuteri strain 100-23 is a true (autochthonous) resident of the murine gut because it adheres to the nonsecretory epithelium of the forestomach and persists at constant population levels in particular regions of the gut throughout the life of the murine host (13, 39).We maintain a colony of mice whose gut microbiota is devoid of lactobacilli but is otherwise equivalent to that of conventional mice (32). These reconstituted Lactobacillus-free (RLF) mice permit the study of Lactobacillus traits against a standardized bacteriological background. L. reuteri 100-23 and the RLF mouse gut therefore provide an appropriate model system with which to study the molecular basis of Lactobacillus autochthony.While L. reuteri 100-23 inhabits the murine gut, genes encoding methionine sulfoxide reductase (msrB), xylose isomerase (xylA), and a protein with low similarity to methionine synthase II (met) are specifically induced (38). Add...

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“…(4)-via a combination of both pentose phosphate and the EM pathway. Thus, the most common initial reactions of bacterial xylose catabolism involve xylose isomerase and xylulose kinase (4,13,23,29,36).…”

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confidence: 99%

Novel Xylose Dehydrogenase in the Halophilic Archaeon Haloarcula marismortui

Johnsen

Schönheit

2004

J Bacteriol

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During growth of the halophilic archaeon Haloarcula marismortui on D-xylose, a specific D-xylose dehydrogenase was induced. The enzyme was purified to homogeneity. It constitutes a homotetramer of about 175 kDa and catalyzed the oxidation of xylose with both NADP ؉ and NAD ؉ as cosubstrates with 10-fold higher affinity for NADP ؉ . In addition to D-xylose, D-ribose was oxidized at similar kinetic constants, whereas D-glucose was used with about 70-fold lower catalytic efficiency (k cat /K m ). With the N-terminal amino acid sequence of the subunit, an open reading frame (ORF)-coding for a 39.9-kDA protein-was identified in the partially sequenced genome of H. marismortui. The function of the ORF as the gene designated xdh and coding for xylose dehydrogenase was proven by its functional overexpression in Escherichia coli. The recombinant enzyme was reactivated from inclusion bodies following solubilization in urea and refolding in the presence of salts, reduced and oxidized glutathione, and substrates. Xylose dehydrogenase showed the highest sequence similarity to glucose-fructose oxidoreductase from Zymomonas mobilis and other putative bacterial and archaeal oxidoreductases. Activities of xylose isomerase and xylulose kinase, the initial reactions of xylose catabolism of most bacteria, could not be detected in xylose-grown cells of H. marismortui, and the genes that encode them, xylA and xylB, were not found in the genome of H. marismortui. Thus, we propose that this first characterized archaeal xylose dehydrogenase catalyzes the initial step in xylose degradation by H. marismortui.The utilization of sugars, in particular of hexoses and hexose polymers and-to a lesser extent-of pentoses, has been reported for various species in the domain Archaea. So far, only the catabolic pathways of hexoses and glucose polymers (e.g., maltose and starch) have been studied in detail in particular in hyperthermophilic, thermoacidophilic, and extremely halophilic archaea. Comparative analyses of glucose degradation pathways in these organisms revealed that the classical Embden-Meyerhof-(EM) or Entner-Doudoroff-(ED) pathway found in bacteria is not operative in archaea; they use instead modified versions of these pathways as follows (for reviews, see references 31 and 41). In hyperthermophilic eury-and crenarchaeota, glucose degradation proceeds predominantly via modified EM pathways, which differ from the classical EM pathway by the presence of several unusual glucokinases (ADP or ATP dependent) and 6-phosphofructokinases (ADP, ATP, or PP i dependent), novel enzymes of glucose-6-phosphate isomerization and of glyceraldehyde-3-phosphate oxidation, and pyruvate kinases with reduced regulatory potential (15,18,41).In thermoacidophilic archaea, Sulfolobus and Thermoplasma spp., glucose is degraded via a nonphosphorylated version of the ED pathway (22,31,41) by which glucose is oxidized to glycerate via the nonphosphorylated intermediates gluconate and 2-keto-3-deoxygluconate (KDG) involving glucose dehydrogenase, gluconate dehydrata...

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Dissolution of Xylose Metabolism in Lactococcus lactis

Cited by 45 publications

References 48 publications

Lactococcus lactis Metabolism and Gene Expression during Growth on Plant Tissues

Lactococcus lactis Metabolism and Gene Expression during Growth on Plant Tissues

A High-Molecular-Mass Surface Protein (Lsp) and Methionine Sulfoxide Reductase B (MsrB) Contribute to the Ecological Performance of Lactobacillus reuteri in the Murine Gut

Novel Xylose Dehydrogenase in the Halophilic Archaeon Haloarcula marismortui

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