PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “PIMELIC ACID”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1975

[The development and the reversion of spheroplasts of a diaminopimelic acid-auxotrophic mutant of Escherichia coli].

1. The formation and reversion of spheroplasts of the diaminopimelic acid-auxotrophic mutant Escherichia coli K 12, 335, DAP-, R+TEM in a medium lacking diaminopimelic acid have been investigated by microphotography: During their development from rod form cells to spheroplasts cells on slide-surface-agar preparations underwent two successive cell divisions in the course of which the cells retained their rod form. The cells formed by these divisions partitioned into a varying number of spheroplasts of different size. The reversion of spheroplasts to rod form cells, started by the addition of diaminopimelic acid showed two characteristic steps: Each spheroplast partitioned again into several spheroplast-like cell bodies; most of them reverted directly to rod form cells. 2. The release of the R-factor mediated periplasmic TEM-beta-lactamase, E. C. 3.4.2.6., into the growth medium during the development of spheroplasts attained more than 50% of the entire TEM-beta=lactamase activity. The spheroplasts showed a multiple enhancement of TEM-beta-lactamase activity per mg cell protein compared with rod form cells.

Culture Media↗
PubMed1969

The effect of magnesium ion deprivation on the synthesis of mucopeptide and its precursors in Bacillus subtilis.

1. Mg(2+) or Mn(2+) starvation causes suspensions of Bacillus subtilis strain W 23 to accumulate bound amino sugars that are soluble in trichloroacetic acid. 2. The presence of chloramphenicol or puromycin produces higher intracellular concentrations of amino sugars during Mg(2+) starvation, but neither compound can stimulate the accumulation when Mg(2+) is present. 3. The major component of the amino sugar fraction extracted from cells deprived of Mg(2+) is a nucleotide containing uridine, phosphorus, N-acetylmuramic acid, alanine, glutamic acid and alphain-diaminopimelic acid in the molar proportions of 1:2:1:3:1:1. This compound represents at least 80% of the bound N-acetylhexosamine extracted by trichloroacetic acid. 4. Studies of the binding of this nucleotide with vancomycin support the proposal that it is the mucopeptide precursor UDP-N-acetylmuramyl-l-alanyl-d-glutaminyl- alphain-diaminopimelyl-d-alanyl-d-alanine. 5. A method is described for the isolation of this material labelled with [(3)H]alphain-diaminopimelic acid. 6. When Mg(2+) is supplied to cells previously starved of Mg(2+), the accumulated pool of amino sugars rapidly decreases. 7. The biosynthesis of mucopeptide is inhibited by 35-50% under conditions of Mg(2+) starvation. The presence of EDTA increases this inhibition to 70%. The amount of N-acetylhexosamine that accumulates is balanced exactly by the associated fall in mucopeptide synthesis. 8. ;Chase' experiments show that the accumulated N-acetylhexosamine compound is utilized in mucopeptide synthesis.

Amino Sugars↗
PubMed1978

[2,6-Diaminopimelic acid (DPA) content and the DPA:N ratio in rumen bacteria in relation to time after feeding].

The interrelation between the time of the withdrawal of rumen fluid and the DPA: N-relation in the fraction of mixed rumen bacteria was ascertained in a test with two cows with rumen fistulae. At the moment of feeding the DPA-content of 63 mg per g bacteria was very high. In the period of 3 to 9 hours after feeding it remained relatively constant (50 mg). A mean conversion relation of 20.4 of DPA to bacteria N was ascertained. The amino acid model proved to be the same in all fractions, the content values were comparable to those found in technical literature.

Amino Acids↗
PubMed1978

DNA replication pattern and cell wall growth in Escherichia coli PAT 84.

An electron microscopic radioautographic study was made of tritiated thymidine incorporation into the genome of Escherichia coli PAT 84 and of tritiated meso-D,L-2,6-diaminopimelic acid (DAP) into the cell envelope. Pulse-labeled cells growing at 30 degrees C with a doubling time of 170 min were classified according to length by the method of agar filtration. Mathematical analysis of the length distribution led to the assumption of an exponential relation between length and time. A novel DNA replication pattern was found. Within the cell cycle DNA replication terminates at 70 min; then a gap follows of 64 min, after which DNA replication is initiated at 134 min. Thus, the C period is 106 min and the D period is 100 min. Cell constriction starts at 141 min and coincides with initiation of DNA replication. Detailed quantitative analysis of the [3H]thymidine grain frequency distribution allowed the distinction of three groups of cells. The first group incorporated no label, the second group an amount C, and the third group an amount 2 X C. The relative contribution of each group to a particular length class was determined. The data fitted very well into the DNA replication pattern. The same analysis was carried out on DAP pulse-labeled cells. Again, three groups of cells could be distinguished, and their relative contributions to each length class was determined. The group with the double amount of label was especially prominent at the end of the cell cycle. The emergence of this group might represent the acquisition of new lateral growth areas.

Cell Cycle↗