Escherichia coli possesses two major systems for inorganic phosphate (P(i)) uptake. The Pst system (pstSCAB) is inducible by low phosphate concentrations whereas the low-affinity transporter (pitA) has been described as constitutively expressed. PitA catalyses transport of metal [Mg(II), Ca(II)]-phosphate complexes, and mutations in pitA confer Zn(II) resistance. Here we report that pitA transcription is not constitutive; activity of a single-copy pitA-lacZ transcriptional fusion (monolysogen) was maximal at high extracellular Zn(II) (150 microM), in the absence of added P(i), and in a well-defined pitA mutant strain. Intracellular zinc levels were unaffected by adding Zn(II) to the medium for both the wild-type and mutant strains. However, in the wild-type strain, Mg levels (per gram of dry biomass) fell by eightfold in cells grown with added Zn(II) and by 20-fold when Zn(II) and P(i) were added to cultures. Mutation of pitA reduced the effects of external Zn(II) and phosphate levels on Mg pools, consistent with competition or inhibition by Zn(II) of PitA. The mechanism of pitA regulation by extracellular Zn(II) and P(i) is unknown but appears not to involve Fur or other well-characterized regulators.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1111/j.1574-6968.2008.01386.x | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Isolation and characterization of ɸEcM-vB1 bacteriophage targeting multidrug-resistant Escherichia coli.
BMC Res Notes
January 2025
Department of Microbiology and Immunology, Faculty of Pharmacy, Damanhour University, Damanhour, Egypt.
Objectives: The aim of this study is to screen for, isolate and characterize a bacteriophage designated ɸEcM-vB1 with confirmed lytic activity against multidrug-resistant (MDR) E. coli. Methods done in this research are bacteriophage isolation, purification, titer determination, bacteriophage morphology, host range determination, bacteriophage latent period and burst size determination, genomic analysis by restriction enzymes, and bacteriophage total protein content determination.
View Article and Find Full Text PDFCarboxymethyl hemicellulose hydrogel as a fluorescent biosensor for bacterial and fungal detection with DFT and molecular docking studies.
Sci Rep
January 2025
Cellulose and Paper Department, National Research Centre, 33 El Bohouth Str, P.O. 12622, Dokki Giza, Egypt.
A new method was developed to quickly produce carboxymethyl hemicellulose (CM-Hemi) and fluorescent nitrogen-doped carbon dots (N-CDs) from sugarcane bagasse (SB). These materials were then combined with calcium chloride (CaCl₂) to create hydrogel sensors with antibacterial and antifungal properties. The CM-Hemi@Ca-N-CDs hydrogel was effective against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria compared to CM-Hemi@Ca which give no antibacterial activity.
View Article and Find Full Text PDFBioBERT based text mining for incorporating prior knowledge in the inference of genetic network models.
Comput Biol Med
January 2025
Health Innovation and Transformation Centre, Federation University, Victoria, 3842, Australia; BioThink, Queensland, 4020, Australia.
Reconstruction of Gene Regulatory Networks (GRNs) is essential for understanding gene interactions, their impact on cellular processes, and manifestation of diseases, including drug discovery. Among various mathematical and dynamic models used for GRN reconstruction, S-system model, comprising non-linear differential equations, is widely utilised to capture the behaviour of complex biological systems with non-linear and time-dependent interactions. However, as the network size increases, computational demand for network inference grows due to a greater number of estimation parameters, significantly impacting the performance of optimisation algorithms.
View Article and Find Full Text PDFIsatidis root polysaccharides ameliorates post-weaning diarrhea by promoting intestinal health and modulating the gut microbiota in piglets.
Vet Q
December 2025
Animal Nutritional Genome and Germplasm Innovation Research Center, College of Animal Science and Technology, Hunan Agricultural University, Changsha, China.
This study aimed to investigate the effects of dietary isatidis root polysaccharide (IRP) on diarrhea, immunity, and intestinal health in weanling piglets. Forty healthy piglets were randomly assigned to five groups receiving varying dosages of IRP. The findings indicated that different concentrations of IRP significantly reduced diarrhea scores ( < 0.
View Article and Find Full Text PDFThe proteome is a terminal electron acceptor.
Proc Natl Acad Sci U S A
January 2025
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125.
Microbial metabolism is impressively flexible, enabling growth even when available nutrients differ greatly from biomass in redox state. , for example, rearranges its physiology to grow on reduced and oxidized carbon sources through several forms of fermentation and respiration. To understand the limits on and evolutionary consequences of this metabolic flexibility, we developed a coarse-grained mathematical framework coupling redox chemistry with principles of cellular resource allocation.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!