Specificity and control of uptake of purines and other compounds in Bacillus subtilis

Abstract

Certain nucleotides control adaptation to changing nutrition or differentiation (sporulation) resulting from a general nutritional deficiency. To maintain the adaptation or differentiation process, once it has started, it may have been important for cells to evolve several independent and metabolically controllable systems enabling the uptake and metabolism of various nucleic acid bases or nucleosides. We have analyzed the cellular reactions with these compounds by measuring both their effect on growth and their uptake in appropriately chosen auxotrophic and uptake mutants. We have found one uptake system for guanine and hypoxanthine, another one for guanosine and inosine, and three other systems for adenine, adenosine, and uracil. The uptake systems of guaninehypoxanthine and guanosine-inosine are inhibited by the stringent response to amino acid deprivation (increase of guanosine 5'-diphosphate-3'-diphosphate), but they do not depend on the concentration of GTP, which decreases during sporulation. In contrast, the uptake of Ura depends on the presence of GTP, regardless of whether a GTP decrease was produced by the stringent response or otherwise. This was the only uptake system whose decrease was always correlated with the onset of sporulation. The uptake of other compounds, e.g., a

[3H]Adenine is a suitable radioligand for the labeling of G protein-coupled adenine receptors but shows high affinity to bacterial contaminations in buffer solutions

“…For E. coli as well as for B. subtilis , two adenine transport systems have been described: a low- and a high-affinity transport system [ 42 , 46 , 47 ]. The latter system is important when the concentration of adenine is low [ 46 , 47 ]. Differences in adenine-binding affinity observed in our studies when intact cells were compared with membrane preparations (Fig.…”

“…Bacteria have developed different transport systems for related compounds, which allow them to independently absorb those compounds. This is an advantage when growing under nutritional deprivation [ 46 , 53 ]. For C. luciliae , a nucleobase transporter that recognizes adenine and hypoxanthine equally well has been described [ 45 ].…”

“…In E. coli , adenine and uracil have different, specific transport systems, as do xanthine and guanine, whereas hypoxanthine might utilize the guanine transporter [ 53 ]. For B. subtilis , specific transport systems for guanine and hypoxanthine, for guanosine and inosine, as well as three independent uptake systems for adenine, adenosine and uracil, have been identified [ 46 ].…”

Regulation of purine biosynthesis by a eukaryotic‐type kinase in Streptococcus agalactiae

“…It is intriguing that while the GBS genome indicates the absence of multiple amino acid biosynthetic pathways, these bacteria have retained the genes essential for de novo purine and pyrimidine biosynthesis. Recently, a number of reports describe purine acquisition in Gram‐positive organisms such as B. subtilis (Beaman et al ., 1983; Saxild and Nygaard, 1987; 1991; Mandal et al ., 2003), Lactococcus lactis (Martinussen et al ., 2003) . However, unlike GBS, the genome of the oral streptococcal pathogen Streptococcus mutans (Ajdic et al ., 2002) shows the existence of genes/enzymes essential for histidine biosynthesis from nucleotide precursors.…”

Letter to the Editor: CORR Insights®: Does Extracellular DNA Production Vary in Staphylococcal Biofilms Isolated From Infected Implants Versus Controls?

“…Vorkapic and colleagues [10] presented the multifaceted roles of extracellular DNA, as mentioned in your CORR Insights 1 , in bacterial physiology. For example, eDNA is a nutrition source, which means the degradation of eDNA destabilizes the biofilm and also serves as deprivation of nutrients in important life cycles of bacteria [2,10]. Therefore, eDNA could be used to combat biofilm-associated infections.…”