Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous work has shown that the side wall of a Gram-positive rod is initially laid down as a compact layer inside the older wall. It is then stretched as it comes to bear tension due to the osmotic pressure inside the cell. If the polar wall is likewise capable of a degree of expansion, then no new murein need be added while the planar cross-wall splits and converts into two poles. In Bacillus subtilis mutant strain FJ6, which is deficient in autolytic enzymes, pole formation can be caused by addition of exogenous muramidase (10 micrograms hen egg white lysozyme ml-1 for 10 min at 35 degrees C). This strain grows as long filaments with many completed cross-walls, but enzymic treatment caused the formation of many new poles of normal morphology as judged by thin section electron microscopy. Fully separated poles of normal appearance were also found when more than 100 times the MIC (1 microgram ml-1) of vancomycin was added to block wall growth totally and rapidly 10 min before the addition of lysozyme. We conclude, therefore, that no new murein is needed in the conversion of the flat septum into poles and that the unstressed cross-wall is capable of the necessary expansion.
J Gen Microbiol 1986 Dec
PMID:Normal pole formation during total inhibition of wall synthesis of Bacillus subtilis. 311 56

Lipopolysaccharide-rich vesicles were released from Acinetobacter calcoaceticus 69V during growth on hexadecane. Vesicle formation occurred over the whole surface of the cell as demonstrated by scanning electron microscopy. In contrast, the surface of acetate-grown cells, for which little lipopolysaccharide was found in the growth medium, appeared smooth. The overall chemical composition as well as the protein and phospholipid composition of the outer membranes of both cell types was very similar. In the vesicles all outer membrane proteins were found with the exception of an Mr 10,000 polypeptide corresponding to Braun's lipoprotein. Compared with the outer membrane, the vesicles contained more phosphatidylethanolamine. Hexadecane-grown cells were susceptible to exogenously added phospholipase. Nevertheless the barrier function towards lysozyme was retained.
J Gen Microbiol 1988 Jul
PMID:Effect of hexadecane-induced vesiculation on the outer membrane of Acinetobacter calcoaceticus. 324 92

Fusion of the alkaline phosphatase gene (phoA) which lacks its own signal peptide sequence to the N-terminal region of hlyA, the structural gene for Escherichia coli haemolysin, leads to active alkaline phosphatase (AP). AP activity depends on the length of the N-terminal region of hlyA. An optimum is reached when 100-200 amino acids of HlyA are fused to PhoA but fusion of as little as 13 amino acids of HlyA to PhoA is sufficient to yield appreciable AP activity. When cells are treated with lysozyme most of the AP activity is found associated with the membrane fraction but a substantial amount is also found in the soluble fraction, most of which may represent a periplasmic pool of AP. The soluble portion of AP activity is significantly increased when the cells are disrupted by ultrasonication, which indicates that the fusion proteins are only loosely associated with the membrane and that large parts are already located on the outside of the cytoplasmic membrane. The expected fusion proteins were identified in the soluble and the membrane fractions and their amounts in these fractions correlated well with AP activity.
Mol Gen Genet 1987 Jun
PMID:Alkaline phosphatase which lacks its own signal sequence becomes enzymatically active when fused to N-terminal sequences of Escherichia coli haemolysin (HlyA). 330 15

An L-form isolated from Escherichia coli K12 by sequential treatment with N-methyl-N'-nitro-N-nitrosoguanidine and lysozyme was adapted to grow in hyperosmolar liquid cultures. It was stable in the absence of antibiotic when cultured in brain heart infusion (BHI) broth containing NaCl and CaCl2, the optimal concentrations being 0.34 M and 1 mM, respectively. No growth of the L-form was observed when CaCl2 was not added to BHI medium containing 0.34 M-NaCl. On the other hand, when KCl replaced NaCl as the osmotic stabilizer, growth of the L-form was repressed in the presence of CaCl2. Electron microscopy of the L-form confirmed the absence of a cell wall. A revertant strain derived from the L-form grew as a stable bacillary form in BHI medium without osmotic stabilizer. The growth characteristics of the revertant strain resembled those of the parent strain. The revertant strain produced L-forms in the presence of NaCl.
J Gen Microbiol 1987 Mar
PMID:Morphology, growth and reversion in a stable L-form of Escherichia coli K12. 330 59

The proteins synthesized in Escherichia coli B cells after infection with various T4 bacteriophage tail baseplate mutants were analysed by the immunoblotting method for the presence of the 15 Kilodalton lysozyme found in phage T4 particles. Using three different antisera: anti-phage, anti-baseplate and anti-15K lysozyme, it has been found that the 15K lysozyme is not present in lysates of bacteria infected with T4 gene 25 amber mutants. The 15K lysozyme was also found to be expressed in E. coli B cells transformed with a plasmid containing only a small portion of the T4 genome but which included T4 gene 25. These observations indicate that the 15K lysozyme is the gene 25 product.
Mol Gen Genet 1986 Mar
PMID:Identification of T4 gene 25 product, a component of the tail baseplate, as a 15K lysozyme. 352 Feb 36

The acrA mutation in Escherichia coli led to a substantial increase of the acriflavine-binding capacity of the cell, whereas the related mutations acrB (gyrB) and arcC did not. Metal ions such as Na+, K+, Mg2+, Ca2+ and Al3+ effectively released the bound acriflavine, in proportion to their ionic strengths. The presence of cations, in fact, increased the survival fraction of the cells in the acriflavine-containing medium. Polymyxin B, an antibiotic which binds to membrane phospholipid, competed with acriflavine for binding sites. Cell wall digestion by treatment with lysozyme and EDTA slightly decreased the acriflavine-binding capacity. Almost no difference was observed in acriflavine-binding capacity between intact cells and cells from which lipopolysaccharide has been extracted (46.9% removed from the acrA cells and 47.4% from the acrA+ cells). Acriflavine bound to the cells was most effectively extracted by ethanol containing 1% HCl or by 2% (w/v) SDS. The difference in the acriflavine-binding capacity between the acrA and acrA+ cells was also observed in the spheroplasts. These facts indicate a relationship between the acrA gene product and the acriflavine-binding capacity of the cells.
J Gen Microbiol 1985 Jul
PMID:Acriflavine-binding capacity controlled by the acrA gene of Escherichia coli. 390 Feb 82

The peptidoglycan of a number of strains of Neisseria gonorrhoeae and Escherichia coli turned over during exponential growth as monitored by the loss of radioactivity (supplied as [14C]glucosamine) from SDS-insoluble material. However, no turnover of the peptide side chains of E. coli peptidoglycan was observed (monitored by diamino[3H]pimelic acid) even though turnover of glycan material was occurring. Turnover rates of 9 to 15% per generation were recorded for all the N. gonorrhoeae strains studied except for the autolytic variant RD5 which showed a higher rate of turnover (20 to 26% per generation). In contrast to previous interpretations, these rates of turnover were not affected by benzylpenicillin, unless sufficient antibiotic was present to affect culture turbidity, when lysis occurred. Examination of the fragments (monomer, dimer and their O-acetylated counterparts, and oligomers) produced by Chalaropsis B muramidase treatment of prelabelled peptidoglycan revealed that no fraction of the peptidoglycan was immune from turnover. However, peptidoglycan pulse-labelled for only 10 min did not show immediate turnover. The lapse of time before turnover commenced was strain dependent, with a maximum value of 1.5 generations. This work confirms that the peptidoglycan of N. gonorrhoeae undergoes a period of maturation and suggests that only mature peptidoglycan turns over.
J Gen Microbiol 1985 Feb
PMID:Turnover of the cell wall peptidoglycan during growth of Neisseria gonorrhoeae and Escherichia coli. Relative stability of newly synthesized material. 392 Mar 47

Small heat-stable, acid-soluble proteins (HASP) have been isolated from Bacillus subtilis nucleoids obtained from cell lysates of low ionic strength and lysozyme concentration. They were identified by their ability to bind homologous and heterologous native and denatured DNA. Four major species, of 8.5, 12, 23 and 26 kDal, were found. Their affinity for DNA was moderate as measured by the sensitivity to ionic strength of the DNA-protein complex (0.1-0.4 M-NaCl). Partial digestion by micrococcal nuclease of the 'low ionic strength nucleoids' released a DNA fragment of 80-120 bp. The data reported here indicate that small basic proteins, together with other components such as RNA, cations and polyamines, may be involved in the compaction of the prokaryotic genome.
J Gen Microbiol 1985 Mar
PMID:Isolation and characterization of small heat-stable acid-soluble DNA-binding proteins from Bacillus subtilis nucleoids. 392 47

A mutation near cysB on the Bacillus subtilis chromosome marks a new sporulation locus, spoVIC. It causes spores to germinate more slowly than those of the wild-type under all conditions and, from indirect evidence, it does not appear to alter the affinity for the germinant L-alanine. The mutant spores have some deficiency of coat proteins (particularly the alkalisoluble coat protein, Mr = 12 000) and the spore coat layers are disorganized. The mutant strain grows normally and sporulates normally until stage II, after which its sporulation is delayed by about 2 h compared to that of the wild-type. This delay results in the prolonged synthesis of some coat proteins and the late synthesis of others. The abnormal coat may be the cause of the germination deficiency. A double mutant strain carrying the spoVIC610 mutation together with gerE36 sporulates slowly. Its spores have very little coat protein, are sensitive to heat, lysozyme and organic solvents, but germinate as well as the strain carrying the spoVIC mutation alone. The role of the spore coat in germination is discussed in the light of these findings.
J Gen Microbiol 1985 Sep
PMID:spoVIC, a new sporulation locus in Bacillus subtilis affecting spore coats, germination and the rate of sporulation. 393 35

Small bacteriocin is a low-molecular-weight bacteriocin which is common in fast-growing rhizobia. As its activity could not be detected in chloroform-sterilized culture supernatants (P.R. Hirsch, J. Gen. Microbiol. 113:219-228, 1979), the bacteriocin could not be purified in order to study its mechanism of action. We report here that small is soluble in chloroform, an observation which led to effective and simple (partial) purification. Other properties of small are its low molecular weight, which is estimated to be between 700 and 1,500, its resistance to proteolytic enzymes, pectinase, and lysozyme, and its heat stability at pH 5.5 but not at pH 7.0. Its bactericidal action on exponentially growing sensitive cells was not detected until 11 h after its addition. The bactericidal action was preceded by inhibition of cell division. To determine whether small activity is required for nodulation or nitrogen fixation, a transposon Tn5-induced small-negative mutant was isolated. The observation that this strain formed normal, acetylene-reducing root nodules showed that small production is not a prerequisite for the formation of effective nodules.
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PMID:Bacteriocin small of fast-growing rhizobia is chloroform soluble and is not required for effective nodulation. 399 74


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