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PubMed1999

Tumour responding accessory cells in testicular seminoma: an immunohistochemical study.

AIM: To investigate the role of accessory cells (and other chronic inflammatory cells) in the host immune response to testicular seminoma by defining their immunophenotypic characteristics and topographical arrangement. METHODS AND RESULTS: A panel of antibodies applicable to paraffin-embedded tissues was employed to characterize the host chronic inflammatory response in eight cases of classical testicular seminoma. The antibodies were directed against CD45RO, CD20, CD68, acid cysteine proteinase inhibitor (ACPI), MAC387, muramidase (MUR), S100 protein, Factor XIIIa, CD21 and HLA Class II. In all cases the majority of the inflammatory cells were T-lymphocytes situated mainly in areas of apparent tumour destruction. Large numbers of macrophages/dendritic cells which had not been evident by conventional light microscopy were also demonstrated. In particular, an immunophenotypically distinct population of accessory cells showing a specific pattern of distribution was revealed. It clearly rimmed islands of tumour and showed strong positive staining for CD68, MAC387 and HLA Class II. CONCLUSION: The study has identified an immunophenotypically distinct population of accessory cells showing a characteristic topographical arrangement. It is proposed that it represents a subpopulation of macrophages which are responding directly to the tumour and are likely to play a part in influencing tumour dynamics.

Adult↗
PubMed2004

The autolytic phenotype of Bacillus thuringiensis.

AIMS: To evaluate the autolytic phenotype of Bacillus thuringiensis. METHODS AND RESULTS: The autolytic rate of 87 strains belonging to different subsp. of B. thuringiensis was examined at pH 6, 6.5 and 8.5 in different buffers under starvation conditions. At pH 6 the extent of autolysis (average in the strain collection 38.3 +/- 21.1) was strain-dependent with wide variability, while at pH 6.5 and 8.5 (averages 72.0 +/- 9.0 and 63.1 +/- 8.2, respectively) it was much more uniform with only a few strains showing low autolytic rates. Forty-one per cent of the strains showed high resistance (>/=80%) to mutanolysin, a commercial muramidase from Streptomyces. The peptidoglycan hydrolase pattern was evaluated by renaturing SDS-PAGE using cells of B. thuringiensis subsp. tolworthi HD125 as indicator. The strain collection showed seven major lytic bands of about 90, 63, 46, 38, 32, 28 and 25 kDa, and in the stationary growth phase (72 h) there was a more intense 25 kDa band in the autolytic pattern. Using Micrococcus lysodeicticus and Listeria monocytogenes as the indicators lytic activity was retained, as seen by the bands of 63, 46, 38, 32 and 25 kDa. Growth in the different media did not affect the autolytic pattern. NaCl abolished the activity of all the peptidoglycan hydrolases in the gel, but in the presence of KCl, MgCl(2), MnCl(2) and EDTA some activity was retained. At basic pH the lytic activity increased. CONCLUSIONS: The autolytic phenotype of B. thuringiensis was found to be strain-dependent, and different proteins exibited peptidoglycan hydrolase activity, particularly at alkaline pH. Several of these proteins retained lytic activity against other bacterial species. SIGNIFICANCE AND IMPACT OF THE STUDY: The characterisation of the autolytic phenotype of B. thuringiensis should expand the prospects of using this species in bacterial bio-control and field applications.

Bacillus thuringiensis↗
PubMed1979

Bovine serum chitinase.

1. A glycol-chitin-splitting enzyme without lysozyme (muramidase) activity has been found in calf serum. The enzyme also degrades colloidal chitin and is thus a true chitinase, 1,4-beta-poly-N-acetylglucosaminidase, without exo-beta-N-acetylglucosaminidase effect. 2. The enzyme is purified 1000-fold by ion-exchange chromatography and gel filtration. Its optimal activity is between pH 1.5-2.0 with glycol chitin and between pH 3-6 in a rather broad optimum with colloidal chitin as substrate. The optimal stability of the enzyme is in the pH interval 3.0-6.5 when tested by incubation with glycol chitin at 50 degrees C for 60 min. The optimal temperature for the degradation of glycol chitin is 40 degrees C when assayed at pH 1.5 and 51 degrees C when assayed at pH 3.5. 3. The enzyme is activated by moderate heating at pH 6.5. The highest relative activity, 135% is reached after 45 min incubation at 30 degrees C, pH 5 or after 30 min at 40, pH 2.4. By incubation with small amounts of trypsin at pH 6.5 at 3m degrees C the enzyme was temporarily activated. 4. The isoelectric point, pH 5.3, and the molecular weight, 47,000 +/- 3,000 were determined by respectively isoelectric focusing and gel filtration. 5. The Michaelis-Menten constant, Km = 0.76 +/- 0.05 (S.E.) mg/ml, was measured with glycol chitin as substrate.

Animals↗
PubMed1995

Purification and characterization of M3 protein expressed on the surface of group A streptococcal type 3 strain C203.

Monoclonal antibodies (mAbs) have been produced by immunizing BALB/C mice with whole M+ bacteria in incomplete Freund adjuvant and the resulting mAbs for M3 protein have been selected by an indirect immuno-fluorescent technique using formaldehyde-fixed M+ and M- bacteria. Four mAbs reacted with a 65 kDa protein in an extract obtained from the cell wall of M+ bacteria after treatment with N-acetyl muramidase and lysozyme. The purified 65 kDa protein neutralized the phagocytic activity of rabbit anti-M3 antibody. The N-terminal amino acid sequence of the 65 kDa protein was identical with that of protein generated by the M3 gene which has been previously cloned and sequenced. The evidence indicates that the 65 kDa protein is M3 protein. The M3 protein bound not only human fibrinogen but also human serum albumin (HSA). When the M3 protein was purified by gel-filtration and ion-exchange chromatography in the absence of phenylmethyl sulfonyl fluoride (PMSF), four fragments (35 kDa, 32 kDa, 30 kDa, and 25 kDa) in addition to the intact molecule appeared. N-terminal amino acid sequence analysis showed that 35 kDa and 25 kDa fragments were ANAAD and DARSV, respectively, being identical at positions 1-5 and 198-202 to the M3 gene derived protein. Therefore, the 35 kDa and 25 kDa fragments, which were presumed to be cleavage products, may be derived from the C-terminal part and N-terminal part of the intact molecule, respectively. When the effect of purified M3 protein in the bactericidal activity of normal human blood in the presence of M- bacteria was investigated, the M3 protein was responsible for the organism's resistance to attack by phagocytic cells.

Animals↗
PubMed1993

Characterization of three different lytic transglycosylases in Escherichia coli.

Two lytic transglycosylases, releasing 1,6-anhydromuropeptides from murein sacculi are present in a mutant deleted for the soluble lytic transglycosylase 70 (Slt70). Thus, there are three different lytic transglycosylases in Escherichia coli. One of the remaining enzymes is soluble and one is a membrane protein that can be solubilized by 2% Triton X-100 in 0.5 M NaCl. Both enzymes are exo-muramidases. Only the membrane enzyme, but not the soluble ones, hydrolyses isolated murein glycan strands (poly-GlcNAc-MurNAc). While the soluble enzymes are inhibited by the muropeptide TetraTriLysArg(dianhydro), the membrane enzyme is not. The antibiotic bulgecin that inhibits Slt70 does not inhibit the lytic transglycosylases present in the slt70 deletion mutant.

Carbohydrate Sequence↗
PubMed1982

Malignant centroblastic-histiocytic lymphoma of the skin.

A mixed B-cell type centroblastic lymphoma with extraordinarily many histiocytes in a 68-year-old man is reported. Multiple skin tumours were the only clinical manifestation during the first 5 months. The disease then progressed to the lymph nodes, spleen, and parenchymal organs, but the bone marrow remained unaffected until death, 11 months after the onset of signs. C3d receptors were the only surface markers of the centroblasts. The histiocytes were normal with respect to morphology, muramidase staining, and Fc and C3b receptors. This highly unusual spread from skin to lymphoid and parenchymal organs is discussed in the light of lymphoid cell kinetics.

Aged↗
PubMed1987

Immunoprofile of benign and malignant fibrohistiocytic tumors.

Formalin-fixed, paraffin-embedded tissue sections from 26 malignant fibrous histiocytomas (MFH) and 61 benign fibrohistiocytic proliferations (BFHP) were evaluated immunohistochemically. An avidinbiotin-peroxidase technique was used to determine immunoreactivity for alpha-1 antichymotrypsin, muramidase, HLA-DR, leucocyte common antigen, S-100 protein, vimentin, desmin, and keratin. MFHs were consistently positive for ACT and vimentin and inconsistently reactive for the other antigens. MFHs were negative for LCA suggesting a mesenchymal origin for these lesions. In the MFH histologic subtypes, antigen expression was not significantly different to be useful in their classification. Also no distinctive pattern emerged relative to immunoreactivity and tumor location. The benign lesions, giant cell tumor of tendon sheath, dermatofibroma, and oral benign fibrous histiocytoma differed from the MFHs in that they were often LCA positive, suggesting origin from hematopoetic mononuclear-macrophages. The immunoprofiles of peripheral fibromas and "giant cell" fibromas were felt to be consistent with origin from mesenchymal cells. Several of the antigens studied could be used to differentiate the benign lesions studied from other benign neoplasms. The antigens were, however, of little value in separation of benign and malignant lesions.

Adolescent↗
PubMed1989

Effect of repeated administration of berenil on urinary enzyme excretion with corresponding tissue pattern in rats.

The effect of repeated administration of berenil, a trypanocide, on urinary excretion of some enzyme activities in rat and their corresponding levels in the kidney and serum was investigated. Daily administration of this drug to rats resulted in increased urinary volume, excretion of protein, alkaline phosphatase and lactate dehydrogenase activities. However, the level of acid phosphatase activity was not significantly increased while muramidase activity disappeared completely during the period of drug administration. In the kidney tissue, there was a significant loss of lactate dehydrogenase activity immediately after the first dose and this trend continued until the end of drug administration. In the same tissue, there was an increase in alkaline phosphatase activity while the lysosomal enzymes were not significantly affected. In the serum, except for the increase in alkaline phosphatase activity, all other enzymes were not significantly affected. All these results indicate that there is cellular damage to rat kidney as a result of repeated berenil administration, and that the plasma membrane and the soluble portion of the cytoplasm are the primary site of injury to the cells. They also suggest that urinary enzyme excretion could be useful in determining the site of cellular damage by chemical agents in kidneys.

Amidines↗
PubMed2006

Endopeptidase and glycosidase activities of the bacteriophage B30 lysin.

Synthetic peptides corresponding to portions of group B streptococcal peptidoglycan were used to show that the endopeptidase activity of bacteriophage B30 lysin cleaves between D-Ala in the stem peptide and L-Ala in the cross bridge and that the minimal peptide sequence cleaved is DL-gamma-Glu-Lys-D-Ala-Ala-Ala. The only glycosidase activity present is that of N-acetyl-beta-D-muramidase.

Bacteriophages↗
PubMed1992

Production of bacteriocin inhibitory to Listeria species by Enterococcus hirae.

A bovine intestinal bacterial isolate, identified as Enterococcus hirae, was found to produce a bacteriocin (designated hiraecin S) inhibitory to Listeria monocytogenes and other Listeria spp. Identification to species level was determined by comprehensive biochemical and morphological tests which were verified by DNA-DNA homology assays. The antimicrobial agent was inactivated by pronase and papain and was insensitive to catalase. The antimicrobial activity was not due to hydrogen peroxide or acid formation, nor was lysozyme or muramidase activity observed in cell-free bacteriocin preparations. Inhibition of selected gram-negative bacteria was not observed. Other enterococci were sensitive to the bacteriocin, and except for Listeria spp., no other gram-positive bacteria tested were inhibited.

Animals↗
PubMed1993

Brochocin-C, a new bacteriocin produced by Brochothrix campestris.

Brochotrix campestris ATCC 43754 produces a bacteriocin inhibitory towards Brochothrix thermosphacta, lactobacilli, Listeria spp., and other gram-positive bacteria. This antimicrobial agent is heat stable, sensitive to proteases, catalase insensitive, and free of organic acids. No phage particles were detected by transmission electron microscopy. Muramidase activity was not detected in the preparations. On the basis of established criteria, the antimicrobial agent was classified as a bacteriocin and named brochocin-C.

Antibiosis↗
PubMed2004

Analysis of the peptidoglycan hydrolase complement of Lactococcus lactis: identification of a third N-acetylglucosaminidase, AcmC.

The peptidoglycan hydrolase (PGH) complement of Lactococcus lactis was identified by amino acid sequence similarity searching of the L. lactis IL-1403 complete genome sequence. Five PGHs that are not encoded by prophages were detected, including the previously characterized AcmA and AcmB proteins. Four of these PGHs, AcmA to AcmD, contain a catalytic domain homologous to that of enterococcal muramidase, but they have different domain structures. The fifth one (YjgB) has sequence similarity with the active-site domain of peptidoglycan-specific endopeptidases. The three new PGH-encoding genes identified in this study are all actively transcribed in L. lactis subsp. cremoris MG1363. The relative abundance of their transcripts varied during growth and was maximal during the early exponential growth phase. The three encoded proteins have peptidoglycan-hydrolyzing activities which are detected only at acidic pHs by zymography. Like AcmA and AcmB, AcmC has N-acetylglucosaminidase activity rather than the N-acetylmuramidase activity predicted by sequence similarity.

Acetylglucosaminidase↗
PubMed1970

Isolation and Characterization of a Protective Antigen-Containing Particle from Culture Supernatant Fluids of Erysipelothrix rhusiopathiae.

The mouse-protective activity of Erysipelothrix rhusiopathiae culture supernatant fluids exists in a polydisperse form, ranging in density from aggregates which sediment at 10,000 x g for 3 hr to soluble units which will not sediment at 198,000 x g for 12 hr. A partially purified protective antigen has been isolated from the aggregates sedimented from a concentrate of the culture supernatant fluid at 20,000 x g for 3 hr. These aggregates contained the major protective antigen or antigens of E. rhusiopathiae, since, in addition to inducing active immunity, they adsorbed essentially all of the passively protecting antibody from rabbit antiserum produced by immunization with whole culture. The protective activity in these aggregates was destroyed by trypsin and greatly diminished by muramidase and heating at 64 C, but was not affected by lipase or ribonuclease.

Journal Article↗
PubMed1979

Phenotypic stability of the cell wall of Streptococcus mutans Ingbritt grown under various conditions.

Quantitative analyses of cell walls from Streptococcus mutans Ingbritt grown under carbohydrate limitation in the chemostat showed that growth conditions had no statistically significant effect on the composition of polysaccharide, peptidoglycan, or the proportion of polysaccharide in the cell wall. Lysis of cell wall preparations with a muramidase supported this conclusion and further indicated that there was little difference in their overall structure. In contrast, there was a consistent difference between the rates of lysis by this enzyme of organisms grown in 0.2% glucose and 0.5% glucose. Extremes of pH or dilution rate essentially did not influence the immunogenicity of type c antigen in whole organisms irrespective of whether the carbohydrate source was glucose or sucrose. However, differences were found in the immunogenicity of lipoteichoic acid under similar circumstances. The results indicated there was an inherent phenotypic stability in the cell walls of S. mutans Ingbritt despite changes in pH, generation time, and carbohydrate source, and that any changes that did occur were probably due to associated cell-surface components.

Alanine↗
PubMed1980

Lysis and protoplast formation of group B streptococci by mutanolysin.

Group B streptococci, refractory to previously tested muralysins under physiological conditions, were successfully converted to protoplasts by use of a recently describede N-acetyl muramidase, mutanolysin, derived from a streptomycete. Purified enzyme was effective, but crude preparations, although degrading cell walls, simultaneously produced peculiar effects of cytoplasmic coagulation, retention of cell shape, loss of some intracellular enzymes, and a rise in optical density. Addition of purified mutanolysin to the array of muralysins (group C streptococcal phage-associated lysin, lysozyme), previously successful in preparing protoplasts of different streptococci, now makes possible enzymatic preparation of protoplasts of streptococci of groups A, B, C. D. G, and H.

Bacteriolysis↗
PubMed1984

Glucose phosphoenolpyruvate-dependent phosphotransferase system of Streptococcus mutans GS5 studied by using cell-free extracts.

The glucose phosphotransferase system (PTS) of Streptococcus mutans GS5 has been partially characterized, using fractions derived from cells treated with the muramidase mutanolysin. Membranes retained functional PTS enzymes for the phosphoenolpyruvate-dependent phosphorylation of glucose, fructose, and mannose. This was confirmed by assaying membranes directly for enzyme I (EI) and enzyme IIglc (EIIglc) by employing specific phosphoryl-exchange reactions for each factor. Membranes prepared from glucose PTS- mutants, however, were either deficient in glucose phosphorylation or reflected the "leakiness" displayed by whole cells. Mutant membranes were unable to catalyze the glucose:glucose 6-phosphate transphosphorylation reaction, indicating a defective EIIglc in these fractions. Although total cellular EI activities in the mutant clones were about the same as that measured for the wild-type strain by employing the pyruvate:phosphoenolpyruvate phosphoryl-exchange reaction, mutant membranes were found to possess less than 10% of the specific EI activity of wild-type membranes. The cytoplasmic fractions of mutants, however, displayed markedly increased specific activities for this enzyme when compared with wild-type extracts. These results strongly suggest a molecular association of EI with a normal membrane protein, perhaps EIIglc, that is absent in mutants. This would explain the absence of fructose PTS activity in glucose PTS- mutant membranes despite the fact that whole cells of these clones are normal for this transport function.

Carbon Radioisotopes↗
PubMed1991

Identification of two proteins associated with virulence of Streptococcus suis type 2.

The protein profiles of various cell fractions of 180 strains of Streptococcus suis type 2, which were isolated from diseased pigs, from healthy pigs when they were slaughtered, and from human patients, were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The isolates from diseased pigs contained two proteins that were absent in most of the isolates from healthy pigs. One of these proteins was a 136-kDa protein that was previously identified as the muramidase-released protein (MRP). This protein was predominantly detected in protoplast supernatants and culture supernatants. The second protein was a 110-kDa protein that was detected only in culture supernatants and therefore was provisionally called extracellular factor (EF). Three phenotypes of S. suis type 2 strains were recognized. Isolates from organs of diseased pigs mainly belonged to the MRP+ EF+ phenotype (77%), while isolates from tonsils of healthy pigs mainly had the MRP- EF- phenotype (86%). Most of the isolates from human patients contained MRP (89%); 74% had the MRP+ EF- phenotype. These findings confirm the results of previous investigations which demonstrated that S. suis type 2 strains differ in virulence. Monoclonal antibodies raised against the 110-kDa EF recognized proteins with higher molecular weights in culture supernatants of all of the strains with the MRP+ EF- phenotype. However, none of the strains with the MRP+ EF+ phenotype produced these high-molecular-weight proteins. Our results demonstrate that MRP and EF are associated with virulence. This suggests that one or both of these proteins are virulence factors that play a role in the pathogenesis of S. suis type 2 infections in pigs and human patients.

Animals↗
PubMed1994

Peptidoglycan fragments decrease food intake and body weight gain in rats.

We hypothesized that peptidoglycan (PG) fragments decrease appetite in rats. Male Lewis rats (150 g; n > or = 7) received intraperitoneal (i.p.) injections of purified soluble PG fragments that had been treated with polymyxin B-agarose to remove residual endotoxin. Food consumption and body weight gain were determined at intervals after injection. Single i.p. injections of macromolecular extensively O-acetylated PG (S-O-PG) and non-O-acetylated PG fragments (24 to 240 micrograms/kg) reduced food intake and body weight gain in a dose-dependent fashion during the first 12 h after injection. Low-molecular-weight disaccharide peptide monomers with nonreducing 1,6-anhydro-N-acetylmuramic acid ends and muramyl dipeptide (MDP; 1.6 mg/kg) were also appetite and weight gain suppressants, albeit at least 10-fold less potent than S-O-PG; however, muramidase-derived monomers and peptide cross-linked dimers with reducing muramic acid ends were inactive. Appetite suppression was not limited to the Lewis rat strain since another strain, F344, exhibited similar decreases in food intake after injection of S-O-PG or MDP. Oral administration of MDP or S-O-PG, at concentrations 3 and 20 times higher, respectively, than those that were active i.p., failed to elicit a hypophagic response. We conclude that soluble PG fragments are potent suppressants of food consumption and body weight gain in rats and that, although macromolecular PG is more potent than low-molecular-weight fragments, neither O-acetylation nor glycosidic linkage of PG fragments is required for activity. We speculate that PG fragments may contribute to loss of appetite during bacterial illness.

Acetylation↗