scholarly journals Uptake of N,N′-Diacetylchitobiose [(GlcNAc)2] via the Phosphotransferase System Is Essential for Chitinase Production by Serratia marcescens 2170

2003 ◽  
Vol 185 (6) ◽  
pp. 1776-1782 ◽  
Author(s):  
Taku Uchiyama ◽  
Ryousuke Kaneko ◽  
Junko Yamaguchi ◽  
Akane Inoue ◽  
Takahiro Yanagida ◽  
...  
Keyword(s):  
Serratia Marcescens ◽  
Carbon Sources ◽  
Major Product ◽  
Essential Factor ◽  
Specific Enzyme ◽  
Phosphotransferase System ◽  
Major Pathway ◽  
Chitin Hydrolysis ◽  
Chitinase Production ◽  
Chitin Binding Protein

ABSTRACT The chiR gene of Serratia marcescens 2170, encoding a LysR-type transcriptional activator, was identified previously as an essential factor for expression of chitinases and a chitin-binding protein, CBP21. To identify other genes that are essential for chitinase production, transposon mutagenesis with mini-Tn5Km1 was carried out, and 25 mutants that were unable to produce chitinases and CBP21 were obtained. Analysis of the mutated gene of one of the mutants, N22, revealed the presence of a pts operon in this bacterium, and a mutation was found in ptsI in the operon. In addition to its inability to produce chitinase, N22 did not grow well on N-acetyl-d-glucosamine (GlcNAc), (GlcNAc)2, and some other carbon sources, most of which were phosphotransferase system (PTS) sugars. Thus, the inability to produce chitinase was assumed to be caused by the defect in uptake of (GlcNAc)2 via the PTS, considering that (GlcNAc)2 is the minimal substrate for chitinase induction and the major product of chitin hydrolysis by chitinases of this bacterium. To confirm this assumption, the chb operon, encoding the (GlcNAc)2-specific enzyme II permease, was cloned by reference to its Escherichia coli counterpart, and the Serratia chb operon was shown to comprise chbB, chbC, bglA, chbR, and chbG. Disruption of chbC drastically reduced production of chitinases and CBP21 and impaired growth on colloidal chitin. These results indicate that uptake of (GlcNAc)2 is mediated by the PTS and that the (GlcNAc)2-specific enzyme II permease constitutes its major pathway. Since (GlcNAc)2 uptake is essential for induction of chitinases and CBP21 production, (GlcNAc)2 appears to be the key molecule in recognition and utilization of chitin by S. marcescens.

scholarly journals Identification of Listeria monocytogenes Genes Contributing to Intracellular Replication by Expression Profiling and Mutant Screening

2006 ◽  
Vol 188 (2) ◽  
pp. 556-568 ◽  
Author(s):  
Biju Joseph ◽  
Karin Przybilla ◽  
Claudia Stühler ◽  
Kristina Schauer ◽  
Jörg Slaghuis ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Stress Proteins ◽  
Carbon Sources ◽  
Brain Heart Infusion ◽  
Nitrogen Sources ◽  
Pentose Phosphate ◽  
Intracellular Growth ◽  
Cell Infection ◽  
Phosphotransferase System ◽  
Isoleucine Leucine

ABSTRACT A successful transition of Listeria monocytogenes from the extracellular to the intracellular environment requires a precise adaptation response to conditions encountered in the host milieu. Although many key steps in the intracellular lifestyle of this gram-positive pathogen are well characterized, our knowledge about the factors required for cytosolic proliferation is still rather limited. We used DNA microarray and real-time reverse transcriptase PCR analyses to investigate the transcriptional profile of intracellular L. monocytogenes following epithelial cell infection. Approximately 19% of the genes were differentially expressed by at least 1.6-fold relative to their level of transcription when grown in brain heart infusion medium, including genes encoding transporter proteins essential for the uptake of carbon and nitrogen sources, factors involved in anabolic pathways, stress proteins, transcriptional regulators, and proteins of unknown function. To validate the biological relevance of the intracellular gene expression profile, a random mutant library of L. monocytogenes was constructed by insertion-duplication mutagenesis and screened for intracellular-growth-deficient strains. By interfacing the results of both approaches, we provide evidence that L. monocytogenes can use alternative carbon sources like phosphorylated glucose and glycerol and nitrogen sources like ethanolamine during replication in epithelial cells and that the pentose phosphate cycle, but not glycolysis, is the predominant pathway of sugar metabolism in the host environment. Additionally, we show that the synthesis of arginine, isoleucine, leucine, and valine, as well as a species-specific phosphoenolpyruvate-dependent phosphotransferase system, play a major role in the intracellular growth of L. monocytogenes.

scholarly journals Sinorhizobium meliloti Mutants Lacking Phosphotransferase System Enzyme HPr or EIIA Are Altered in Diverse Processes, Including Carbon Metabolism, Cobalt Requirements, and Succinoglycan Production

2008 ◽  
Vol 190 (8) ◽  
pp. 2947-2956 ◽  
Author(s):  
Catalina Arango Pinedo ◽  
Ryan M. Bringhurst ◽  
Daniel J. Gage
Keyword(s):  
Carbon Metabolism ◽  
Sinorhizobium Meliloti ◽  
Carbon Sources ◽  
Deletion Mutants ◽  
Symbiotic Relationship ◽  
Wild Type ◽  
Phosphotransferase System ◽  
Carbon Utilization ◽  
Carbon Regulation ◽  
Extreme Sensitivity

ABSTRACT Sinorhizobium meliloti is a member of the Alphaproteobacteria that fixes nitrogen when it is in a symbiotic relationship. Genes for an incomplete phosphotransferase system (PTS) have been found in the genome of S. meliloti. The genes present code for Hpr and ManX (an EIIAMan-type enzyme). HPr and EIIA regulate carbon utilization in other bacteria. hpr and manX in-frame deletion mutants exhibited altered carbon metabolism and other phenotypes. Loss of HPr resulted in partial relief of succinate-mediated catabolite repression, extreme sensitivity to cobalt limitation, rapid die-off during stationary phase, and altered succinoglycan production. Loss of ManX decreased expression of melA-agp and lac, the operons needed for utilization of α- and β-galactosides, slowed growth on diverse carbon sources, and enhanced accumulation of high-molecular-weight succinoglycan. A strain with both hpr and manX deletions exhibited phenotypes similar to those of the strain with a single hpr deletion. Despite these strong phenotypes, deletion mutants exhibited wild-type nodulation and nitrogen fixation when they were inoculated onto Medicago sativa. The results show that HPr and ManX (EIIAMan) are involved in more than carbon regulation in S. meliloti and suggest that the phenotypes observed occur due to activity of HPr or one of its phosphorylated forms.

Fate of Fluorodifen in Resistant Peanut Seedlings

Weed Science ◽  
1971 ◽  
Vol 19 (3) ◽  
pp. 261-265 ◽  
Author(s):  
E. F. Eastin
Keyword(s):  
Arachis Hypogaea ◽  
Major Product ◽  
Amino Derivative ◽  
Water Soluble ◽  
Ether Linkage ◽  
Major Pathway ◽  
Natural Plant ◽  
Rapid Absorption ◽  
Root Treatment ◽  
Plant Substances

Rapid absorption and limited acropetal movement of 14C from p-nitrophenyl-α,α,α-trifluoro-2-nitro-p-tolyl ether (hereafter referred to as fluorodifen) labeled with 14C at either the 1 position of the p-nitrophenyl ring (fluorodifen-1′-14C) or the trifluoromethyl carbon (fluorodifen-14CF3) were observed in peanut (Arachis hypogaea L., var. Starr) seedlings after root treatment for 48 hr followed by 96 hr in nutrient solution. Major products of degradation of fluorodifen-1′-14C were p-nitrophenol and Unknown I (possibly a conjugate of p-nitrophenol). Some p-nitrophenyl-α,α,α-trifluoro-2-amino-p-tolyl ether and several minor unknowns were detected. The major product of degradation of fluorodifen-14CF3 was Unknown II (possibly a conjugate of 2-amino-4-trifluoromethylphenol). Some 2-amino-4-trifluoromethylphenol and traces of p-nitrophenyl-α,α,α-trifluoro-2-amino-p-tolyl ether, p-aminophenyl-α,α,α-trifluoro-2-nitro-p-tolyl ether, p-aminophenyl-α,α,α-trifluoro-2-amino-p-tolyl ether, and several minor unknowns also were detected. A major pathway of fluorodifen degradation in peanut seedlings is postulated whereby fluorodifen is reduced to the 2-amino derivative which is cleaved at the ether linkage to yield p-nitrophenol and 2-amino-4-trifluoromethylphenol. The respective phenols are then conjugated with natural plant substances to form water soluble conjugates.

scholarly journals Sugar-mediated regulation of a c-di-GMP phosphodiesterase in Vibrio cholerae

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Kyoo Heo ◽  
Young-Ha Park ◽  
Kyung-Ah Lee ◽  
Joonwon Kim ◽  
Hyeong-In Ham ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Carbon Sources ◽  
Phosphotransferase System ◽  
Host Colonization ◽  
Host Immune Responses ◽  
Gut Colonization ◽  
Host Diet ◽  
Underlying Mechanisms ◽  
Cyclic Dinucleotide

AbstractBiofilm formation protects bacteria from stresses including antibiotics and host immune responses. Carbon sources can modulate biofilm formation and host colonization in Vibrio cholerae, but the underlying mechanisms remain unclear. Here, we show that EIIAGlc, a component of the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS), regulates the intracellular concentration of the cyclic dinucleotide c-di-GMP, and thus biofilm formation. The availability of preferred sugars such as glucose affects EIIAGlc phosphorylation state, which in turn modulates the interaction of EIIAGlc with a c-di-GMP phosphodiesterase (hereafter referred to as PdeS). In a Drosophila model of V. cholerae infection, sugars in the host diet regulate gut colonization in a manner dependent on the PdeS-EIIAGlc interaction. Our results shed light into the mechanisms by which some nutrients regulate biofilm formation and host colonization.

scholarly journals Convergent Pathways for Utilization of the Amino Sugars N-Acetylglucosamine,N-Acetylmannosamine, and N-Acetylneuraminic Acid by Escherichia coli

1999 ◽  
Vol 181 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Jacqueline Plumbridge ◽  
Eric Vimr
Keyword(s):  
Escherichia Coli ◽  
Carbon Sources ◽  
Amino Sugars ◽  
Good Growth ◽  
Gene Products ◽  
Phosphotransferase System ◽  
Regulatory Mutation ◽  
Putative Gene ◽  
Acetylneuraminic Acid ◽  
K 12

ABSTRACT N-Acetylglucosamine (GlcNAc) andN-acetylneuraminic acid (NANA) are good carbon sources forEscherichia coli K-12, whereasN-acetylmannosamine (ManNAc) is metabolized very slowly. The isolation of regulatory mutations which enhanced utilization of ManNAc allowed us to elucidate the pathway of its degradation. ManNAc is transported by the manXYZ-encoded phosphoenolpyruvate-dependent phosphotransferase system (PTS) transporter producing intracellular ManNAc-6-P. This phosphorylated hexosamine is subsequently converted to GlcNAc-6-P, which is further metabolized by the nagBA-encoded deacetylase and deaminase of the GlcNAc-6-P degradation pathway. Two independent mutations are necessary for good growth on ManNAc. One mutation maps tomlc, and mutations in this gene are known to enhance the expression of manXYZ. The second regulatory mutation was mapped to the nanAT operon, which encodes the NANA transporter and NANA lyase. The combined action of thenanAT gene products converts extracellular NANA to intracellular ManNAc. The second regulatory mutation defines an open reading frame (ORF), called yhcK, as the gene for the repressor of the nan operon (nanR). Mutations in the repressor enhance expression of the nanAT genes and, presumably, three distal, previously unidentified genes,yhcJIH. Expression of just one of these downstream ORFs,yhcJ, is necessary for growth on ManNAc in the presence of an mlc mutation. The yhcJ gene appears to encode a ManNAc-6-P-to-GlcNAc-6-P epimerase (nanE). Another putative gene in the nan operon, yhcI, likely encodes ManNAc kinase (nanK), which should phosphorylate the ManNAc liberated from NANA by the NanA protein. Use of NANA as carbon source by E. coli also requires thenagBA gene products. The existence of a ManNAc kinase and epimerase within the nan operon allows us to propose that the pathways for dissimilation of the three amino sugars GlcNAc, ManNAc, and NANA, all converge at the step of GlcNAc-6-P.

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